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WATERSHED PLAN and ENVIRONMENTAL IMPACT STATEMENT am am 141, WAIMANALO WATERSHED CITY AND COUNTY OF TC 424 HONOLULU, HAWAII M U56 1981 JULY 1981 U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE WAIMANALO WATERSHED City and County of Honolulu, Hawaii DRAFT WATERSHED PLAN AND ENVIRONMENTAL IMPACT STATEMENT July 1981 ABSTRACT This document describes the formulation, implementation, and effects of a local- federal cost-shared project to solve problems with inefficient use of water and related resources and severe limitations on the production of crop6-in Waimanalo. The project also takes advantage of an opportunity to enhance the agricultural use of prime and important farmlands. Land treatment, improved irrigation water management, irrigation use of treated sewage effluent and rehabilitation and expansion of the existing irrigation system were investigated in formulating alternative plans including a no-action plan. Economic benefits exceed costs for the proposed plan. Sponsors will pay 52 percent of the $12.798 million installation costs. Environmental impacts include increased agricultural use of prime and important fa rmlands, reduced solid waste disposal problems, and protecting or preserving portions of the existing ditch determined to have historic value. This document is intended to fulfill requirements of the National Environmental Policy Act, and the Water Resources Council Principles and Standards for Water and Related Land Resources Planning. This document is to be considered for authorization of Public Law 83-566 funding. Prepared under the authority of the Watershed Protection and Flood Prevention Act, Public Law 83-566, as amended (16 USC 1001-1008) and in accordance with Section 102(2)(C) of the National Environmental Policy Act of 1969, Public Law 91-190, as amended (42 USC 4321 et seq). Prepared By: STATE OF HAWAII, DEPARTMENT OF LAND AND NATURAL RESOURCES DIVISION OF WATER AND LAND DEVELOPMENT P. 0. Box 621 Honolulu, Hawaii 96809 WINDWARD OAHU SOIL AND WATER CONSERVATION DISTRICT P. 0. Box 402 Kaneohe, Hawaii 96786 UNITED STATES DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE (Lead Agency) For additional information and to comment on this draft, contact: Jack P. Kanalz, State Conservationist Soil Conservation Service P. 0. Box 50004 Honolulu, Hawaii 96850 Telephone (808)546-3165 COMMENTS MUST BE RECEIVED BY OCTOBER 17, 1981 polcYrIerty M NOAA Coastal Sei-Aces Center Library WATERSHED AGREEMENT between the STATE OF HAWAII, DEPARTMENT OF LAND AND NATURAL RESOURCES (Referred to herein as DLNR) WINDWARD OAHU SOIL AND WATER CONSERVATION DISTRICT (Referred to herein jointly with, DLNR as Sponsors) STATE OF HAWAII and the SOIL CONSERVATION SERVICE UNITED STATES DEPARTMENT OF AGRICULTURE (Referred to herein as SCS) Whereas, applitation has heretofore been made to the Secretary of Agriculture by local. organizations for assistance in preparing a plan for works of improve- ment for the Waimanalo Watershed, State of Hawaii, under the authority of the Watershed Protection and Flood Prevention Act (16 U.S.C. 1001-1008); and Whereas, the.responsibility for administration of the Watershed Protection and Flood Prevention Act, as amended, has been assigned by the Secretary of Agricul- ture to the Soil Conservation Service (SCS); and Whereas, there has been developed through the cooperative efforts of the local organizations and the SCS a plan for works of improvement for the Waimanalo Watershed, State of Hawaii, hereinafter referred to as the watershed plan, which plan is annexed to and made a part of this agreement; Now, therefore, in view of the foregoing considerations, the' Secretary of Agriculture, through the SCS, and the Sponsors hereby agree on this plan and that the works of improvement for this project will be installed, operated, and maintained in accordance with the terms, conditions, and stipulations provided for in this watershed plan and including the following: 1. The Sponsors will provide or acquire, with other than P.L. 566 funds, such landrights as will be needed in connection with the works of improvement. (Estimated cost $740,000.) 2.- The DLNR assures that comparable replacement dwellings will be available for individuals and persons displaced from dwellings, and will provide relocation assistance advisory services and relocation assistance, make the relocation payments to displaced persons, and otherwise comply with the real property acquisition policies contained in the Uniform Relocation Assistance and Real Property Acquisition Policies Act of 1970 (Public Law 91-646, 84 Stat. 1894) effective as,of January 2, 1971, and the Regulations issued by the Secretary of Agriculture pursuant thereto. The costs of relocation payments will be shared by the Sponsors and SCS as follows: Estimated Relocation DLNR SCS PUment Costs Tp-ercent) Tp-ercent) (dollars)- Relocation Payments 52 48 $ 0 3. The DLNR will acquire such water rights pursuant to State'law as may be'@ needed in the installation and.operation of the works of improvement. 4. The percentage of construction costs to be paid by DLNR and by SCS are as' follows: Estimated Works of Construction Improvement DLNR SCS Costs Tp-ercent) Tp-ercent) (dollars@_ Irrigation Systems 50 50 $ 8,280,000 Solid Waste Collection Sites 50 50 $ 60,000 (Maunawili Collection 21 System Improvements) (100) (0) ($1,500,000) - 5. The percentages of the engineering costs to be borne by DLNR and by SCS are as follows: Estimated Works of Engineering Improvement DLNR SCS Costs Tp-ercent) Tp-ercent) (dollarsT- Irrigation Systems 0 100 $ 825,000 Solid Waste Collection Sites 0 100 $ 6,000 (Maunawili Collection 2/ System Improvements) (100) (0) ($100,000) - 1/ Investigation has disclosed that under present conditions the project measures will not result in the displacement-of any person, business, or ,farm operation. However, if relocations become necessary, relocation payments will be cost-shared in accordance with the percentages shown. 2/ This is a project construction cost of $500,000 'and engineering costs of $33,000 ineligible for assistance and required for water collection system improvements outside Waimanalo Watershed. An additional construction cost of $1`000,000 and $67,000 engineering costs are assumed in the future wit;out-project for improvements by DLNR outside the watershed. 6. DLNR and SCS will each bear the costs of Project Administration which they incur, estimated to be $651,000 and $1,087,000, respectively. 7. The Sponsors will obtain agreements from owners of not less than 50 percent of the land above each reservoir and floodwater retarding structure that they will carry out conservation farm or ranch plans on their land, and insure that 50 percent of the land is adequately protected prior to construc- tion of any dam. 8. The Sponsors will provide assistance to landowners and operators to assure the installation of the land treatment measures shown in the watershed plan. 9. The Sponsors will encourage landowners and operators to operate and maintain the land treatment measures for the protection and improvement of the watershed. 10. DLNR will be responsible for the operation, maintenance, and replacement of the works of improvement by actually performing the work or arranging for such work in accordance with agreements to be entered into prior to issuing invitations to bid for construction work. 11. The costs shown in this plan represent preliminary estimates. In finally determining the costs to be borne by the parties hereto, the actual costs incurred in the installation of works of improvement will be used. 12. This agreement is not a fund obligating document. Financial and other assistance to be furnished by SCS in carrying out the plan is contingent upon the fulfillment of applicable laws and regulations and the availability of appropriations for this purpose. 13. A separate agreement will be entered into.between SCS and DLNR before either party initiates work involving funds of the other party. Such agreements will set forth in detail the financial and working arrangements and other conditions that are applicable to the specific works of improvement. 14. This plan may be amended or revised only by mutual agreement of the parties hereto except that SCS may deauthorize funding at any time it determines that the Sponsors have failed to comply with the conditions of this agreement. In this case, SCS shall promptly notify the Sponsors in writing of the deter- mination and the reasons for the deauthorization of project funding, together with the effective date. Payments made to the Sponsors or recoveries by SCS shall be in accord with the legal rights and liabilities of the parties when project funding has been deauthorized. An amendment to incorporate changes affecting a specific measure may be made by mutual agreement between SCS and the Sponsors having specific responsibility for the measure involved. 15. No member of or delegate to Congress, or resident commissioner, shall be admitted to any share or part of this plan, or to any benefit that may arise therefrom; but this provision shall not be construed to extend to this agreement if made with A corporation for its general benefit. 16. The program conducted will be in compliance with all requirements respecting nondiscrimination as contained in the Civil Rights Act of 1964, as amended, and the regulations of the Secretary of Agriculture (7 CFR 15.1-15.12), which iv provide that no person in the United States shall, on the ground of race, color, or national origin, be excluded from participation in, be denied the benefits of, or be otherwise subject to discrimination under any activity receiving Federal financial assistance. DEPARTMENT OF LAND AND By NATURAL RESOURCES P.O. Box 621 Title Honolulu, HI 96809 Date The signing of this plan was authorized by a resolution of the Board of Land and Natural Resources adopted at a meeting held on P.O. Box 621, Hon"olulu, HI 96809 Clerk Date WINDWARD OAHU SOIL AND By WATER CONSERVATION DISTRICT P.O. Box'402 Title Kaneohe, HI 96786 Date The signi ng of'this plan was authorized by a resolution of the board of directors of the Windward Oahu Soil and Water Con.servation Di-strict held on P.O. Box 402, Ka.neohe,,HI 96786 Secretary Date SOIL CONSERVATION SERVICE UNITED STATES DEPARTMENT OF AGRICULTURE Approved by: Jack P. Kanalz, State Conservationist Date: CONTENTS Section Page WATERSHED AGREEMENT ------------------------------------------- ii CONTENTS ------------------------------------------------------ vi SUMMARY ------------------------------------------------------- 1 INTRODUCTION -------------------------------------------------- 5 GENERAL -------------------------------------------------- 5 R-E-A-D-E-R-rS GUIDE ------------------------------------------- 5 PROJECT SETTING ----------------------------------------------- 7 TOPOGRAPHY ----------------------------------------------- 7 LAND USE AND SOILS --------------------------------------- 7 'C-LIMATE -------------------------------------------------- 7 70-CIAL AND ECONOMIC CHARACTERISTICS ---------------------- 8 HISTORY AND LAND OWNERSHIP ------------------------------- 8 WATER ---------------------------------------------------- 9 Irrigation ------------------------------------------ 9 Streams --------------------------------------------- 9 @T-ound water ---------------------------------------- 9 Treated Sewage Effluent ----------------------------- 10 FISH AND WILDLIFE ---------------------------------------- 10 VISUAL RESOURCES ----------------------------------------- 10 PROBLEM AND OPPORTUNITY IDENTIFICATION ------------------------- 11 EARLY IDENTIFICATION ------------------------------------- 11 CURRENT PLANNING ----------------------------------------- 11 OTHER PROBLEMS ------------------------------------------- 11 TABLE A - PROBLEMS AND OPPORTUNITIES ---------------------- 12 INVENTORY AND FORECASTING ------------------------------------- 16 GENERAL -------------------------------------------------- 16 SCOPING OF CONCERNS -------------------------------------- 16 FORECASTING CONDITIONS ----------------------------------- 16 THE RESULTS ---------------------------------------------- 17 TABLE B - INVENTORY AND ANALYSIS OF RESOURCES AND FORECASTING ------------------------------------- 18 FORMULATION OF ALTERNATIVES ----------------------------------- 20 GENERAL -------------------------------------------------- 26 T-O-RMULATION PROCESS -------------------------------------- 20 TA-BLEC - EFFECTIVENESS OF MEASURES AND ACTIONS ---------- 21 Irrigation Considerations --------------------------- 22 Flood Prevention ConTiM-erations --------------------- 22 NED F-@T-mulation ------------------------------------- 23 EQ FoTm-u-1a'tion -------------------------------------- 23 vi Section Page FORMULATION OF ALTERNATIVES (continued) EVALUATION OF ALTERNATIVES ------------------------------- 24 ALTERNATIVE 1 NED ------------------------------- 26 ALTERNATIVE 2 EQ ------------------------------- ;-- . 28 ALTERNATIVE 3 NONSTRUCTURAL --------------------- 30 ALTERNATIVE 4 RECOMMENDED ----------------------- 32 ALTERNATIVE 5 WITHOUT PROJECT ------------------- 34 ALTERNATIVE 6 LINED DITCH ----------------------- 36 ALTERNATIVE 7 CO-MBINED WITH BWS ----------------- 38 ALTERNATIVE 8 PIPE SERVICE TO EXISTING USERS ---- 40 CANDIDATE PLANS - ----------------------------------------- 41 TABLE D - SUMMARY COMPARISON OF CANDIDATE PLANS ------ 42 PROJECT INTERACTION -------------------------- ----------- 44 TABLE E - INTERACTION WITH OTHER PROJECTS ---------------- 44 RISK AND UNCERTAINTY ---------------------- ---------------- 45 COMPARISON OF CANDIDATE PLANS ---------------------------- 46 RECOMMENDED PLAN ---------------------------------------------- 47 GENERAL -------------------------------------------------- 47 PURPOSE -------------------------------------------------- 47 PLAN EUEMENTS -------------------------------------------- 47 Va'imanalo Irrigation Syste ----------------------- 47 Treated Sewage Effluent Irrigation System ----------- 47 Solid Waste Collection Sites ----------------------- 48 Land Treatment -------------------------------------- 48 Technical Assistance -------------------------------- 48 Landrights ----------------------------------------- 48 RESERVOIR SAFETY ----------------------------------------- 48 TABLE F - RESIDENCES AND AREAS SUBJECT TO FLOODING IN THE EVENT OF A STRUCTURAL FAILURE ------------------- so MITIGATION ------------------------- --------------------- 50 PERMITS AND COMPLIANCE -------------------------------- 51 TABLE G - COMPLIANCE OF THE RECOMMENDED PLAN WITH WRC-DESIGNATED ENVIRONMENTAL STATUTES --------------- 52 COSTS ------------;--------------------------------------- 7-- 53 INSTALLATION AND FINANCING ----------------------------- 54 TABLE H - SCHEME OF-OBLIGATIONS ------------------------ 54 Responsibi ities ------------------------------------ 54 Landrights and Utilit es ---------------------------- 55 Contracting ------------------------------------------ 55 Financing ------------------------------------------ 55 Nn'ditions for Providing Assistance ----------------- 56 Cultural Resources'--';-7 ------------------------------ 56 OPERATION MAINTENANCE AND REPLACEMENT -------------------- 57 General --------------------------------------------- 57 Operation ---- --------------------------------------- 57 Maintenance ----------------------------------------- 57 Inspection ------------------------------------------ 58 Repl.aceme,nt ----------------------------------------- 58 vii Section Page RECOMMENDED PLAN (continued) TABLES (NUMBERED) TABLE 1 - ESTIMATED INSTALLATION COST --------------- 59 TABLE 2 - ESTIMATED COST DISTRIBUTION --------------- 60 TABLE 2A - COST ALLOCATION AND COST SHARING SUMMARY - 61 TABLE 3A - STRUCTURAL DATA - RESERVOIRS ------------- 62 TABLE 3B - STRUCTURAL DATA - PIPELINES -------------- 64 TABLE 4 - PROJECT EFFECTS --------------------------- 67 EFFECTS OF RECOMMENDED PLAN ----------------------------------- 72 GENERAL -------------------------------------------------- 72 SIGNIFICANT EFFECTS -------------------------------------- 72 FR-OJECT EFFECTS SHOWN IN TABLE 4 ------------------------- 73 EFFECTIVENESS OF THE RECOMMEN PLAN -------------------- 75 EFFECTS ON NATIONALLY RECOGNIZED RESOURCES ---------------- 77 TABLE I - EFFECTS OF THE RECOMMENDED PLAN ON RESOURCES OF PRINCIPAL NATIONAL RECOGNITION ------------------- 78 RELATIONSHIP TO OTHER PLANS AND POLICIES ----------------- 79 Water Resources Regional Study ---------------------- 79 Coastal Zone Management Plan ------------------------ 79 State Functional Plans - Hawaii State Plan ---------- 79 County General Plan --------------------------------- 80 CONSULTATION AND PUBLIC PARTICIPATION ------------------------- 81 GENERAL -------------------------------------------------- 81 AGENCY-CONSULTATION -------------------------------------- 81 PUBLIC PARTICIPATION ------------------------------------- 83 LIST OF PREPARERS --------------------------------------------- 84 REFERENCES ---------------------------------------------------- 86 INDEX --------------------------------------------------------- 88 APPENDICES ---------------------------------------------------- 90 APPENDIX A (RESERVED FOR EIS COMMENTS AND RESPONSES) APPENDIX B PROJECT PHOTOS APPENDIX C MAP - AREA SUBJECT TO FLOODING IN THE EVENT OF STRUCTURAL FAILURE APPENDIX D ENGINEERING DRAWINGS Plate I - Plan and Profile - Regulating and Storage Reservoir Plate 2 - Details - Regulating and Storage Reservoir Plate 3 - Structure Details Plate 4 - Details-Treated Sewage Effluent Use Plate 5 - Solid Waste Collection Sites APPENDIX E PROJECT MAP AND OTHER MAPS Figure 1 - Project Map (Can be unfolded for reference while reading the Plan-EIS) Figure 2 - Agricultural Lands Importantto the State of Hawaii Figur@-3 --Land Use and Flood Plain viii SUMMARY Project Name: Waimanalo Watershed, City and Cou nty of Honolulu, Hawaii Sponsors: Hawaii Department of Land and Natural Resources (DLNR) and Windward Oahu Soil and Water Conservation District Description of The recommended plan will irrigate a total of Recommended Plan: 1,252 acres. Waimanalo Irrigation System (WIS) will be replaced with a gravity-pressure, piped distribution system providing continuous service at full supply to 890 acres. A deep, off-channel reservoir will be used for storage, regulation and nematode control. A separate system will be used for irrigating 68 acres with treated sewage effluent. BWS'service will continue to 294 acres. Accelerated technical assistance and solid waste collec- tion sites will be provided. Alternatives 34 alternative plans were considered covering@ Considered: the following: without project, nonstructural (improvements in the facilities and operation of the existing system), lined ditches, com- bining with the Board of Water Supply (BWS) domestic system, and various combinations of reservoir sizes, area served and water quality. Alternative structural and non- structural flood prevention measures were also considered. Resource Information: Size-Of Watershed 6,132 acres (105 farm units) Land Use - 3,029 acres agriculture 334 acres urban or residential 994 acres military 257 acres parks and recreation 1,518 acres in preservation Land Ownership - 16 percent Federal 18 percent Private (fee simple) 66 percent State owned (31 percent of state land is leased to farmers) Water Available for Irrigation - MG/rY-R- 548 - Maunawili, 128 - effluent, 71 - BWS Wetlands 56 acres secondary wetlands (Ref. 11 & 12) Flood Plain (100 year) 456 acres agri culture. "'idb6tial' 26 acres urban - res, 77 acres parks@'(an&'goffi@cburse) 251 acres military 68 acres beach Endangered Species - Hawaiian Duck, Hawaiian Coot, Hawaiian Gallinule, and Hawaiian Stilt (Ref. -12) Cultural Resources - There are 12 known archeologicAl sites and one historical site under consideration for nomi- nation to the National Register (Ref 17 & 18). Problem Identifications: Because of the antiquated irrigation system and insufficient storage there is inefficient use of "water and related resources and severe limitations on production of crops. Flooding and solid waste disposal are also problems. Op o rtunit, Improve the use of prime and important farm- p Identifications: lands for agriculture, and allow effective implementation of the Agricultural Park Plan. There is also an opportunity to preserve the historic features of the irrigation ditch. Cand-idate Plans Four candidate plans and the without-project Cons_idered@, plan were chosen from the 34 alternatives considered. From these five'the Sponsors could select the recommended plan: (1) NED, the national economic development plan, similar to the recommended plan, but applying less than a full supply of water and thereby maximizing i.rrigated acres; (2) EQ, the environmental qual.ity plan, similar to the recommended plan but irrigating only'prime farmland and pro- viding solid waste collection ' sites; .0) Nonstructural usingrepairs, some modifi- cation, and management techniques to improve the existing system;. and _(4) the recommended plan. The without-project plan was also considered and was the basis for comparison of the candidate plans. Project Purpose: NED Agricultural water management-irrigation, .EQ Environmental enhancement by increasing agri- cultural use of prime and important farmlands and by alleviating solid waste problems. (Flood prevention proved not viable.) 2 Project Cost: SUMMARY DATA FROM TABLE 1 Principal Project PL-566 Funds Other Funds Total Measures ($1000) Percent ($1000) Percent ($1000) Land Treatment 0 589 100 589 Technical Assistance 20 74 7 26 27 Construction Costs Water CF111-e-cf-T-on System 0 500 100 500 Irrigation 4,140 50 4,140 50 8,280 Solid Waste@Sites 30 50 30 50 60 Engineering Services 831 96 33 4 864 Landrights 0 740 100 740 Project Administration 1,087 63 651 37 1,738 TOTAL PROJECT 6,108 48 6,690 52 12,798 1/ Data are from Table I and do not include costs that would be incurred without a project. Project Benefits: Agricultural Irrigation - $916,000 annual net remaining benefits Acres Benefited - 958 gross acres land treatment 0 gross acres nonstructural 958 gross acres structural Impacts: To Land Irrigated by WIS Including Sewage Land Use Changes - From with Full Supply NonirrigateU -cropland 308.acres Irrigated - Board of Water Supply 79 acres Undeveloped Agricultural land 122 acres TOTAL 509 acres Natur al Resources With no loss of significant natural resources, Changed or Lost 377 acres of prime and important farmland will be added to irrigated agricultural production. The new reservoirs will occupy 13.6 acres and the solid waste collection sites 0.2 acres. Other Impacts Major Conclusions - Implementation of the Waimanalo Watershed project will facilitate development of the State's proposed Waimanalo Agricultural Park and ensure the viability of diversified agriculture in Waimanalo. In agreement with county and state planning goals, this future generates a higher quality environment than the future without-project. 3 Areas of Potential- Controversy may surface over future use 'of the, agricultural lands in Waimanalo Watershed. Some interests ma favor urban development, and therefore not support a modern, efficient irrigation system. Transfer of water from Maunawili Watershed, where Kawainui Marsh is, to Waim.analo Water- shed may be controversial,--even thoughthis transfer has long been a source of irrigation water for Waimanalo. Some objection may arise to the use of treated* sewage effluent for crop irrigation. Minor disagreements@may surface between individual operators concerning pipeline alignment, etc. Issues to be Resolved The State's decision to implement the Waimanalo Agricultural Park Plan is yet to be'resolved. Realization of the Agricultural Park Plan is partly dependent on the installation of the irrigation measures included in the Waimanalo Watershed Plan. Prior to expenditure of P.L. 566 contruction funds, the-State must acquire long-term water rights and make collection system improvements. 4 INTRODUCTION GENERAL The watershed plan and environmental impact statement (plan and EIS) for this project have been combined into a single document. The document describes plan formulation, discloses the expected environmental and economic impacts, and provides the basis for authorizing federal assistance for implementation. The plan was prepared under the authority of the Watershed Protection and Flood Prevention Act, Public Law 83-566 as amended (16 USC 1001-1008). The EiS is in accordance with Section 102(2)(c) of the National Environmental Policy Act of 1969, Public Law 91-190, as amended (42 USC 4321 et 5eq.). Responsibility for compliance with the National Environmental PTIicy Act rests with the U.S. Department of Agriculture, Soil Conservation Service (SCS). The sponsoring local organizations (Sponsors) which requested planning assistance are the Hawaii Department of Land and Natural Resources (DLNR) and the Windward Oahu Soil and Water Conservation District. The Sponsors participated in the development of the watershed plan and EIS. The SCS provided technical assistance to the Sponsors in the development of the plan. Other federal, state, and local agencies, groups, and individuals participated in the planning process. This plan was prepared to integrate with the Waimanalo Agricultural Park Plan (Report R61), which was published by DLNR (Ref. 1). The specific purpose of the proposed Agricultural Park Plan is to preserve and expand diversified farming in Waimanalo. READER'S GUIDE The format of the plan and EIS is dictated by various regulations and guidelines. This reader's guide describes the planning process arid guides the reader in finding items of particular interest. Appendix E contains the Project Map, Figure 1, which can be folded out for reference while the plan-EIS is being read. Planning begins with the Sponsor's request for assistance in solving water and related land resource problems. Interagency and interdisciplinary planners then follow a process that involves six basic steps--identify problems and opportunities; inventory resources and forecast future conditions; formulate alternative plans; evaluate effects of the alternatives; compare the alterna- tives; and select a recommended plan. The environmental evaluation and planning process continues through the publica- tion of the Draft to the Final Plan-EIS, cycling back through the six steps and adding refinements in each cycle. This document summarizes the process and presents the results. The recommended plan is the result. The Contents gives a complete listing of the principal topics covered in the document. The Watershed Agreement, although included in the front of the 5 document, is the culmination of the planning effort and-serves as the formal agreement (not the fund obligating document) between the Sponsors and the SCS: The Summary describes the finished plan in brief. It should not be used as the source of information if a complete understanding of the project is needed. The Project Setting actually begins the presentation by describing the area and its resources. Problem and Opportunity Identification covers the reasons for initiating the plan and examines problems and opportunities uncovered during the planning process. Table A, Problems and Opportunities, is a detailed listing. The photos in Appendix B will aid in understanding these two sections. The next section, Inventory and Forecasting, evaluates specific resources and the effect of various project actions on those resources. The future conditions of those resources in year 2000 and year 2020 are forecast for a future without the project. Table B, Inventory and Analysis of Resources and Forecasting, presents this information. The heart of the planning process is in the next section, Formulation of Alternatives. This section covers the process of formulaJing alternaiTve ,pl.ans, how the plans were compared to one another and, finally, how the recom- mended plan was selected. The next two sections, Recommended Plan and Effects of the Recommended Plan, describe in detail.the plan proposed for implementation and its effects on the economy and the environment. These two sections should be read carefully for a tho,rough understanding of what is proposed and what the effect's will be of install.ing the proposed project. In addition to the Project,Map, Figure 1, several other maps and drawings are included in Apendices*D and E. Appendix C is a map showing the area that could.be flooded in the extremely unlikely event that either the existing or proposed reservoir structures should fail. The acreage figures presented in the plan and EIS are gross acres. Gross acres include the farmland occupied by the farmer's buildings, roads, ditches, ponds, etc. The supporting data for the plan and EIS were developed on a net acre basis considering only the acres actually growing a crop'. In Waimanalo net acreage is about 73 percent of the gross acreage. Any questions the reader may have should be referred to the State Conserva- tionist, SCS, whose address and phone number are listed on the flysheet. 6 PROJECT SETTING TOPOGRAPHY Waimanalo Valley contains about 12 square miles, and it is the southernmost valley on the windward or northeast shore of the Island of Oahu. The valley is bounded on the south by the cliffs (pali) of the Koolau Mountains; on the west by Aniani Nui Ridge and Keolu Hills which separate it from Maunawili Valley; and on the east by Waimanalo Bay. Photo No. 1 and the Project Map, Figure 1, Appendix E, show the area. The valley floor occupies about half the valley and has less than 12 percent slope (Photo No. 5). The foothill area has 12-20 percent slope and contains about 5 percent of the land. Slopes vary from 20 percent to vertical in the remaining upper watershed The highest point is Puu 0 Kona peak with an elevation of 2,200 feet. LAND USE AND SOILS The watershed project area contains 6,132 acres of which 3,029 acres are agricultural; 334 acres are urban or residential; 994 acres are military reser- vation; 257 acres are parks and recreation; and 1,518 acres are preservation. See the Land Use Map, Figure 3, Appendix E. There are 105 farming units including nurseries with 822 acres irrigated (often only partially). Soils in the valley include the Haleiwa, Hanalei, Pohakupu and Waialua Series. These soils are high-plastic silts, but they have the characteristics of silty clays, silty clay loam and clay. The soils are usually deep and moderately well drained, except for the Hanalei which is somewhat poorly drained. Erosion hazard is generally slight (Ref. 2). About 2,174 acres, excluding military and residential lands, are classified as prime and important farmlands and are shown in Figure 2, Appendix E. Approximately 56 acres on Bellows Air Force Station are classified as secondary wetlands in accordance with the classifica- tion system used in Hawaii (Ref. 11 and 12). Wetlands are shown in Figure 3, Appendix E. CLIMATE The climate in Waimanalo ranges from hot and dry along the shore to wet and cool at higher elevations. Temperatures in town range from 56'F to 89*F with an average annual of 730F. Prevailing winds are from the northeast, but southwest winds associated with Kona storms can damage crops. Average annual rainfall varies greatly across the valley from below 30 inches at the shore to over 80 inches in the Koolaus. The maximum storm of record occurred on March 5 and 6, 1958, with over 18 inches of rain in 30 hours on the valley floor (Ref. 3). 7 SOCIAL AND ECONOMIC CHARACTERISTICS The population of Waimanalo Valley increased 13 percent from 6,777 in 1970 to 7,674 in 1980, according to the U.S. Census. The valley has one of the highest proportions of native Hawaiians and part Hawaiians of any community on Oahu. Relative proportions are 65 percent in Waimanalo to 15 percent for all Oahu. Residents of the valley generally have larger and younger families and lower per capita income than prevails for the rest of Oahu. Housing.in Waimanalo is primarily single family, privately owned or being purchased--67 percent as compared to 44.3 percent for Oahu. Many residents in Waimanalo Valley have a common goal--they have expressed a strong determination to retain the rural character of this valley, and they have an appreciation for the importance of a viable diversified agriculture in achieving their goal (Ref. 5). On.ly 216 percent of the work force are employed in agriculture--nearly all of these in Waimanalo Valley. Honolulu is the source of most employment. There is very little commercial or service development in the valley, and most of , the shopping is done either in neighboring Kailua or in Honolulu. Income from service and sales to tourists is relatively insignificant in the valley. Current annual gross value of agricultural production in the valley is esti- mated to exceed $12,000,000 (Ref. 4). Hawaii has a goal of greater production of its consumed fruit and vegetables. At present over two thirds of this fresh produce is imported (Ref. 23 and 27), HISTORY AND LAND OWNERSHIP (Ref. 3, 6, and 7.) Some of the earliest habitation sites are located on Bellows Air Force Station. Twelve archeological s 'ites, mostly religious temples (Heiaus), have been identified inthe watershed. The Waimanalo Irrigation System ditches may ,have historic value, and they are under consideration for nomination to the National Register. In the land division (great mahele) of King Kamehameha III during 1846 to' 1848,, the approximately 7,000 acre Waimanalo Valley (Ahupuaa) was reserved as "Crown lands." During 1846 and 1851 native Hawaiians were awarded fee simple, patents for their homesites and cultivated lands (kuleanas). Over the period 1850 to 1920 one family leased the King's land and acquired about 200 acres of fee simple kuleanas. They raised livestock and later devel- oped a sugarcane plantation and the Waimanalo Sugar Company. The sugar company was liquidated in 1947. Leased land was sublet to local farmers, and-fee simple lands were sold. The company leases on state land expired in 1953 and pressures for additional farmland led to the state selling 63 lots of about 9 acres each on the valley floor. In 1921 the Hawaiian Homes-Commission Act listed most of the valley floor'as 11available lands" but excluded military areas, cultivated cane lands, and beach lands. The first Hawaiian Homes Commission lots were made available in 1925. The Hawaiian Homes Commission assigned 30 lots in 1958. 8 Presently the land ownership is in three major categories: by the federal government for Bellows Air Force Station which was established in 1917 (994 acres); in fee simple (1089 acres); and by the state (4049 acres). State land is leased to Hawaiians in the Hawaiian Homes Commission developments, and to other farmers in the valley. Also a small amount of land is owned by public utility companies. WATER Irrigation Irrigation water for Waimanalo sugar plantation came from three sources--Maunawili Valley springs and tunnels, Kawainui Marsh, and Waimanalo Lagoon. As Waimanalo Valley shifted from sugar to diversified agriculture, irrigation water requirements decreased and, eventually, only Maunawili Valley was retained as the source. Transfer of water from Maunawili through Aniani Nui Tunnel was measured by the U.S. Geological Survey from 1954 to 1968 and ranged from approximately 500 to 800 million gallons per year (Ref. 1 and 20). Waimanalo Irrigation System (WIS), a part of DLNR, operates and maintains the Maunawili collection system and the distribution system in Waimanalo. Irrigation water quality tests indicated the presence of plant-parasitic nema- todes, suspended solids, and debris. These could have a significant effect on irrigated agriculture (Ref. 21 and 28). Streams Wa-T-manalo watershed is drained by two major stream systems--Waimanalo is a gaged perennial stream with an average annual discharge of 1.17 billion gallons, and Inoaole Stream is intermittent. The estimated peak flows into Waimanalo Bay for the most severe storm likely to occur once in 100 years are 14,000 and 12,500 cubic feet per second, respectively (Ref. 19). Kailua Reservoir impounds flows on a portion of Waimanalo Stream. A typical foothill channel is shown in Photo No. 7, and Photo No. 13 shows a typical valley-floor channel. The quality of both streams was evaluated as part of a flood control study in 1976 and water quality was generally satisfactory (Ref. 19). These findings were confirmed by testing done for this plan-EIS (Ref. 28). Some physical qualities of these streams are attributable to the "flashy" characteristics. High turbidity and suspended sediment concentrations occur during heavy rainfall, but storms are usually of short duration, and the streams revert to clear, base flow conditions within a few hours (Ref. 24). Waimanalo stream is assigned Ecology Quality Status II (moderateto high quality) as a fish habitat (Ref. 29). Ground Water Ground water in Waimanalo occurs as brackish basal water, dike-impounded water, and perched (or alluvial) water. The dike-impounded ground water is in dike-intruded lava flows in the Koolau Mountains, and is high-quality water suitable for domestic use without treatment. The permeable rock containing the brackish basal water is overlain by caprock materials. Although not presently considered suitable for domestic use, brackish basal water may be important for future needs. 9 The alluvial ground water is generally lower quality than.the dike-impounded water and also important primarily as a resource for future use (Ref. 19 and 24). To protect ground water quality, the Board of Water Supply (BWS) has established a water conservation line that approximately parallels the Waimanalo Forest Reserve Boundary shown on the Project Map, Figure 1, Appendix E. The line is just downslope or towards the sea (makai) of the boundary. No cesspools are allowed uphill or toward the mountains (mauka) of the water conservation line. Treated Sewage Effluent The WaImanalo sewage7-reatment Plant currently discharges about 350,000 gallons per day of secondary treated effluent into three deep injection wells below the basal water. The plant is designed for 1.1 million gallons per day. Water quality tests indicate that this effluent would be suitable for irrigation,(Ref. 22 and 28). FISH AND WILDLIFE (Ref. 12) Four endangered birds are found in the vicinity of the wetlands--Hawaiian .Duck, Hawaiian Coot, Hawaiian Gallinule, and Hawaiian Stilt. Numerous other birds have been observed in the watershed including: Common Mynah, Barred Dove, Spotted Dove, Japanese White-eye, Red Crested Cardinal, Cardinal, Red- rented Bulbul, Spotted Munia, House Sparrow, and Cattle Egret. Kailua Reservoir contains bullfrogs, Tilapia, and Mosquito fish. WIS does not authorize recreational use of the reservoir. @WaimAnalo Stream contains Hawaiian Prawn, Tahitian Prawn, Goby, Guppy, and Green Swordtail (Ref. 29). An interagency survey determined that the fish and wildlife habitat in the area is not unique, and the species observed, other than the endangered birds,. are common introduced species. There is no critical habitat for the endangered species within the watershed. Visual Resources Waimanalo Watershed is a visually pleasing area, framed on the south by spectacular cliffs (Photo No. 3) and on the northwest by high foothills,. Aniani Ridge and Olomana Peak (Photos No. 4 and No. 14). The vertical rock cliffs are softened by channels cut deeply into the face and mosses growing in the.continual dampness. The foothills have a mixture of trees, brush, and open grassy areas (Photo No. 3). The valley floor presents a pattern of fields with diverse plants--highlighted by the often colorful nursery crops. The WIS reservoirs and ditches, mostly tree-lined, break up the straight property lines. The beautiful white sand beach with a backdrop of trees is considered by many to be Oahu's finest (Ref. 3). One serious visual blight, particularly along the foothill edge of the valley floor, is the refuse dumped along the rural roads (Photo No. 14). 10 PROBLEM AND OPPORTUNITY IDENTIFICATION EARLY IDENTIFICATION The identification of problems and opportunities is vital to successful development of a project plan. The process is dynamic and passes through several cycles as data are collected and alternatives are formulated. Early planning by the Territory and, later, the State addressed many of the problems and opportunities covered by the Waimanalo Watershed Plan (Ref. 3 & 8). Problems were stated in the May 1978 application for planning assistance sub- mitted by the Sponsors: Farm production is limited by irrigation water availability and quality, and the irrigation system is inefficient and unreliable. Also, flooding causes damages to residential and agricultural areas. An interdisciplinary, interagency, field examination documented the problems stated in the application. A public meeting was also held to discuss water and related resource problems in Waimanalo (Ref. 9). CURRENT PLANNING After SCS planning assistance was authorized in Janaury 1979, a comprehensive study was undertaken to identify and evaluate problems as well as opportunities. Previous studies, interviews, interagency consultation, and public workshops and meetings were used. Table A separates the broad categories of problems and opportunities into general headings (A through F) and more comprehensively describes specific problems or opportunities under these headings. This same method of presenting problems and opportunities is applied in the Formulation of Alternatives section. OTHER PROBLEMS Kailua Reservoir on Waimanalo Stream would be a hazard in the highly unlikely .event of a sudden structural failure. Several additional problems and opportunities were investigated and found to be comparatively insignificant. They included the problem of declining coral in Waimanalo Bay, reduced wildlife habitat associated with abandoning the irrigation ditches, limited recreation opportunities, erosion from croplands, and critical area erosion. With the exception of one small critically eroding site, these topics were not addressed in the plan formulation stage. TABLE A PROBLEMS AND OPPORTUNITIES Waimanalo Watershed, Hawaii Note. GeneAat priob" and oppoittunitiu, aAe tetWed A thkough G betow. Spec i6ic p4obtent-s and oppattunitie.6 a4e nunb"ed. A. GENERAL PROBLEM WITH INADEQUATE IRRIGATION SYSTEM - WAIMANALO IRRIGATION SYSTEM (WIS) 1. Specific Problem - Undependable supply and operation a. Problems with the collection system in Kaunavili Watershed 1) State purchases irrigation water annually from a private owner. The contract can be terminated on a 30-day notice. 2) Collection system includes 20 wooden flume-trestle structures and 2.8 miles of open ditch which are in very poor condition and highly susceptible to storm damage and vandalism. Much of the system is not readily accessible by equipment for timely repairs and maintenance (Ref. 20). b. Problem with the distribution system in Waimanalo Watershed 1) Distribution system includes two principal reservoirs, Haunswili and Kailua, and two smaller reservoirs with a combined regulation storage of 13 million gallons. As a result, irrigation deliveries can be mode only 3 days out of 7 (Photo No. 4). 2) Distribution system*includes 32 wooden flume-trestle structures and 15 miles of open ditch in generally poor condition. The system is susceptible to storm damage and vandalism (Photo Nos. 2, 6, 7, and 8). 2. Specific Problem- InAdequate amount of water to irrigate 1,873 acres of irrigable Waimanalo farmlands a. Problems with the collection system in Kaunawili Watershed 1) 1.8 million gallons per day are purchased, but 2.4 million gallons per day could be available for collection. 2) Flumes leak and ditches have seepage losses with high water use by ditch bank vegetation (Ref. 20). Losses are estimated to be 11 percent of the total amount collected. b. Problems with the distribution system in Wal"nalo 1) Flumes leak and ditches and reservoirs have seepage losses with high water use by vegetation (Ref. 20). Losses are estimated to be as high as 74 percent of the total amount collected (Photo Nos. 6 and 8). These maximum losses occur during peak-use months. 2) The first hour or two of flow on each irrigation day is used to flush ditches and flumes of debris, and to ensure that there are no residual-herbidides from WIS weed control. 3. Specific Problem Poor water quality limits use and management opportunities a. Plant-parani.tic nematodes are-a serious problem in WaimAnalo (Ref. 21). 1) WIS water is susceptible to infestation by plant-parasitic nematodes, particularly, as a result of storm runoff from infested fields into the open ditches. The shallow reservoirs and ditches play a major role in the distribution of nematodes into and within the area (Ref. 21). 2) Infestation of plant-parao,iticinerhatodes reduces truck crop and banana production (Ref. 21). 3) Nurseries that ship stock to California (a major market) have to be certified as nematode-free to meet the state's quarantine requirements. JULY 1981 TABLE A - PROBLEMS AND OPPORTUNITIES (Continued 2) Waimanalo Watershed, Hawaii 3. Specific Problem Poor water-quality limits use and management opportunities (Continued) b. Other water contamination problems associated with open ditches and reservoirs 1) Farmers are concerned with potential for WIS water transporting herbicides, pesticides, and plant diseases onto their fields. 2) Farmers are concerned with potential for weed seeds being transported throughout the valley by the WIS water. 3) Solids in the water, particularly organic matter, severely limit the use of sprinkler and drip irrigation technologies (Ref. 28). 4. Specific Problem - Nonpressurized system requires energy for pumping for sprinkler or drip application. B. GENERAL PROBLEM WITH LIMITATIONS OF IRRIGATION SYSTEM - BOARD OF WATER SUPPLY (BWS) 1. Specifi@ Problem - Primarily a domestic water supply system a. BWS is operated by the City and County of Honolulu with top-quality ground water to meet the domestic and commercial needs of Oahu. BWS is not managed as an agricultural water supply system, and some farmers question BWS's ability to meet the needs of agriculture in Waimanalo in the future. Demand for potable domestic water is projected to exceed the rati of ground water recharge in the early 1990's (Ref. 14). b. Current rates are $0.76 per 1,000 gallons with periodic increases anticipated as energy and operation costs increase. c. New connections 6r increases in meter size for existing users) are limited by the availability of water and facilities. Development costs are high. C. GENERAL OPPORTUNITY TO UTILIZE TREATED SEWAGE EFFLUENT FOR IRRIGATION 1. Specific Opportunity - Approximately 128 million gallons per year of secondary treated sewage effluent is discharged into three deep injection wells at the Waimanalo Sewage Treatment Plant (Ref. 22 and 24). a. Treated effluent is discharged and serves no useful purpose. b. Three existing wells are nearing their capacity to accept effluent, although, the sewage plant is currently operating at only 1/3 of its design capacity. 2. Specific Opportunity - Irrigable state lands are close to the sewage plant (Ref. 24). a. Aproximately 120 acres 'of state-owned cropland suitable for surface irrigation (as required for sewage effluent) is located within approximately I mile of the sewage plant. b. opportunity exists for experimental use of treated sewage effluent on the Waimanalo Experiment station, University of Hawaii, College of Tropical Agriculture and Human Resources. JULY 1981 TABLE A PROBLEMS AND OPPORTUNITIES (Continued 3) Waimanalo Watershed, Hawaii D. GENERAL OPPORTUNITY TO RETAIN THE PRIHE AND IHPORTANT FARMLAND IN QAIKANALO IN AGRICULTURE 1. Specific Opportunity - Privately owned land zoned for agriculture in Waimanalo includes 841 acres of prime and important farmland. Of that amount, only about 219 acres are currently under irrigation by WIS. a. Considerable pressures exist to allow additional subdivision on these lands (Ref. 23). b. A major factor limiting successful agricultural operations is the availability of good quality, dependable irrigation water (Ref. 23 and 24). 2. Specific Opportunity - State-owned land utilized for agriculture in Waimanalo includes 1,333 acres of prime and important farmland. Of that amount, only about 230 acres are currently under irrigation by WIS. a. The proposed State Agricultural Park Plan will play a major role in retaining prime and important farmlands in agriculture. The irrigation system proposed in the Waimanalo Watershed Plan is a key factor in the realization of the Agricultural Park Plan (Ref. I and 23). E. GENERAL PROBLEM WITH FLOODING 1. Specific Problem 'Flooding associated with frequent storm events a. Flooding is identified by residents as a problem (Ref. 5). 1) significant property damage is infrequent (Ref. 19). 2) Nuisance flooding is widespread on the valley floor causing minor damages. 3) Potential exists for public health problems associated with flooding. 4) Land development opportunities are limited by zoned land use patterns. Zoning recognizes the 100-year floodplain of the existing channel systems. b. Farmers also identify flood problems (Ref. 9). 1) Use of some fields is seasonally restricted by flooding. 2) Nuisance flooding complicates or delays some cultural practices. c. Lack of,maintenance is identifLed by residents anf farmers an a major contributor to flood problems (Photo No. 13). 1) citizens have difficulty in identifying the agency responsible for a particular ditch, stream, culvert, bridge, etc. 2) Agencies are reportedly not clear on who is responsible. 3) obvious maintenance problems are not resolved in a timely or systematic manner. JULY 1961 A TABLE A - PROBLEMS AND OPPORTUNITIES (Continued 4) Waimanalo Watershed, Hawaii F. GENERAL PROBLEM WITH WASTE DISPOSAL- 1. Specific Problem - Citizens have identified solid waste disposal as a problem in Waimanalo (Ref. 5 and Photo No. 14). a. Garbage in being dumped along rural roads in the area, particularly at certain intersections. 1) Dumped garbage and abandoned cars are a visual blight on the community (Ref. 3 and 5). 2) Dumped materials pose a potential health problem, and material is often washed into stream. 3) Dumped materials restrict the capacity of drainages and plug culverts. G. GENERAL OPPORTUNITY TO PRESERVE HISTORICAL SITES 1. Specific Opportunity - Identify portion of WIS ditch which may have historical value. Preserve or protect features determined to be historically significant. JULY 1981 INVENTORY AND FORECASTING GENERAL As a part of the planning process, an inventory was made to determine the quantityand quality of water resources and related land resources in Waimanalo. The'inventory was also used to identify opportunities.for protection and enhance- ment of these resources as discussed in the previous section, Problems and Oppor- tunity.Identification. The planning process also includes forecasting changes inthe,resource conditions that would occur without the project. SCOPING OF CONCERNS The inventory and analysis of resources included an interactive proce':5 termed "scoping" in which affected federal, state, and local agencies, and other interested groups or persons participated. Scoping was used in developing the Waimanalo Plan-EIS to ensure that all significant decisionmaking factors were addressed and that unneeded and extraneous studies were not undertaken. Through the scoping process such resources as wildlife habitat (other than wetlands and Kailua Reservoir), fish habitat, coral in Waimanalo Bay, minerals, and air quality were eliminated from the items that required discussion in this plan. After early phases of inventory and analysis were accomplished and plan formula- tion proceeded, additional scoping and investigation revealed that some resources, although important, would not be significant to decisionmaking with the problems and alternatives being considered. FORECASTING CONDITIONS In order to forecast the most likely conditions to expect without the Waimanalo Watershed Project (future without plan), two scenarios were formulated. The worst-case scenario forecasts the eventual termination of Waimanalo Irrigation System (WIS) and results in extensive conversions from agricultural land.use to other uses. The second case, determined to be the most likely, forecasts a continuation of present conditions. WIS would continue service to existing users, reliability would be improved by the acquisition of long-term water rights, and vital structural repairs would be made to the irrigation collection system in Maunawili Watershed. One general assumption that influences forecast changes in a resource is the conflict between urbanization of Waimanalo and retaining and enhancing the area as a rural community. Although the future without project assumes WIS continues in operation and farming continues at the present rate, the idle farmland will be under increasing pressure to convert to residential-commercial use. The viability of an expanded, diversified agriculture community will be supported by the Agricultural Park Plan, the dependable high-quality irrigation water, and the related technical assistance provided by implementing the Waimanalo Watershed Plan. 16 Forecasting was done in full considerati.on.of state and.county forecasts, plans, concerns, policies, and regulations that would have an influence.. The directors of the State Department of Agriculture and the State Department of Land and Natural Resources were consulted in developing the without-plan projec- tions. THE RESULTS The results of the inventory of resources and forecasting are presented in Table B, Waimanalo Watershed, Inventory and Analysis of Resources and,Forecast@in. The table.presents three aspects of a particular resource: 1) a list 'of important natural resources and the significance,of the effects of various types of,project actions on these resources; 2) baseline information on important resources; and 3) conditions forecast without installation of the Waimanalo Watershed Plan. @17 TABLE B INVENTORY AND ANALYSIS OF RESOURCES AND FORECASTING Waimanalo Watershed, Hawaii SIGNIFICANCE OF THE EFFECT OF BASELINE DATA FORECAST CHANCES WITHOUT PROJECT ACTIONS ON RESOURCES EXISTING RESOURCE WAIMANALO WATERSHED PROJECT (L LOW N - MEDIUM H - HIGH) PROJECT ACTIONS REPAIR REPLACE IRRI_ IRRI_ LIKED RESOURCES EXIST. DITCH NEW GATE GATE FLOOD DITCH WITH RESER- MORE WITH CHAN- YR.2000 YR.2020 REMARKS & RES. PIPE VOIR LAND SEWAGE NELS UNITS QUANr. QUANT . QuANT. 1. Coral Reefs - Waimanalo Bay L L L L L H - - - Increased peak flood discharges could affect coral reefs (Ref. 10). 2. Wetland I Bellows AFS L L L L L H Acres 56 56 56 Area identified by federal and state-Ss secondary (Ref. 11). 3. Threatened & Endangered L L L L L M No. of 3 Sam Sam No change in Bellows AFS wetland Species (water birds) Species habitat (Ref. 12). 4. Floodpla-ins L L L L L H Acres 878 Less Less Increased urbanization will tend 00 then than to reduce floodplains (Ref., 19). present Yr.2000 5. Prime & important Farmlands L K N H H M Acres 822 Less Leas Increased urbanization will tend Farmed than than to reduce prime and important present Yr.2000 farmlands in agriculture. 6. Waimanalo Stream Flow Volume L L L L L H iG/YR 1168 Same Same 1% Peak L L L L L H efs 7500 increase Increase Increased urbanization will increase runoff peaks (Ref. 19). 7. Waimanalo Stream - Quality L M L L L M Meets state std. Quality may Increased urbanization may for fresh water decrease reduce water quality. 8. Ground Water L M L M M L Increased importance Alluvial water could be contaminated by poor irri- gation water management. 9. Municipal (BWS) Water (See remarks) Demand (1975) 38 61 Oahu has a projected average (Kaneohe HydrolOgiL Area 11) 21 year water deficit of 43 MG/D by 2020 for the total island (Ref. 14). 10. Municipal (BWS) Water Used L M M M M A(;/Yi( 71 Less Less Intensive agriculture will continue for Ag. Crop Production than than to demand BW% water, but domestic and in Waimanalo present present commerical uses will probably prevail over agriculture. JULY 1981 TABLE B INVENTORY AND ANALYSIS OF RESOURCES AND FORECASTING (continued 2) Waimanalo Watershed, Hawaii SIGNIFICANCE OF THE EFFECT OF BASELINE DATA FORECAST CHANCES WITHOUT PROJECT ACTIONS ON RESOURCES EXISTING RESOURCE WAIMANAL0 WATERSHED PROJECT (L LOW N - MEDIUM H - HIGH) PROJECT ACTIONS REPAIR REPLACE IRRI_ IRRI_ LINED RESOURCES ExtsT. DITCH NEW- CATE CATE FLOOD DITCH WITH REBER- MORE WITH CHAN- YR.2000 YA.2020 4 RES. PIPE VOIR LAND SEWAGE HELS UNITS QUANT. QUANT. QUANT. 11. irrigation (WIS) Water - L H H H H L iG/YR 128 252 252 State's improvements to Maunswili Quantity Delivered collection system will. improve reliability and reduce losses 12. Irrigation (WIS) Water - L N H L H L Poor quality Remains poor State's improvements to the collection Quality system will not reduce suspended solids or nematodes. 13. Visual Resources on Valley Floor 4 Foothills Landscape Diversity L M M H H H Acres in 822 Less Less Increased urbanization will reduce farm& the land being farmed and change, the appearance (Ref. 15). Visible Structures L N H L L H No. 0 0 0 No change in irrigation structures. Visible Solid Waste L L L L L L No. Dump 6 6 @6 Continue to dump waste along-road*. areas 14. Character of Human L M M H H M Farm units 105 Less Less Increased urbanization will reduce Environment the number of farms and decreases the rural characteristics of the area. 15. Population - Waimenalo L L L M H M No. (1980) 7674 9450 12,000 Projection is based on state baseline (9-2). adjusted for slower growth in Waimanalo than in Oahu. Regional pion recommends 10,000 maximsm to maintain rural character. 16. Archeological Sites L M L H M M No. 12 May May state policy is to promote preser- (Known) Increase Increase vation, protection, and enhancement of important sitem (Ref. 6. 7. 17 & 26). 17. Historical Site H L,, L L L Hiles is Less Less Reduction of farming operations may Existing WIS Ditch result in sections of the ditch (Submitted for nomination being abandoned (Ref. 18 4 26). to National Register) JULY 1981 FORMULATION OF ALTERNATIVES GENERAL At this step of the planning process alternative plans were formulated to make a net contribution to national economic development (NED) and to environ- mental quality (EQ). These alternative plans consisted of structural and nonstructural measures formulated to alleviate the specific problems or to take advantage of specific opportunities. The scoping process described earlier was used in the initial conceptual phase of formulating alternatives to assure consideration of all measures, strategies and programs that might do the job. These alternatives were not limited to -those directly implementable under Public Law 566. Consideration was also given to the cooperative role of local, county, state, federal, and nongovernment interests in implementation of alternatives. Several alternative plans, including the without project condition, are required by the Water Resource Council Principles and Standards for Water and Related Land Resources Planning (18 CRF Part 711). These are the national economic development plan (NED), the environmental quality plan (EQ), and the primarily nonstructural plan. Also, land treatment and water conservation were fully integrated into plan formulation as a means of achieving NED and EQ objectives. When the various alternative plans were evaluated and compared, certain plans were identified as candidate plans. Candidate plans are ones that could be selected as the recommended plan. The candidate plans were compared and the rationale established for selecting the recommended plan. FORMULATION PROCESS The major objective in formulating alternative plans was to alleviate the specific problems and to take advantage of the specific opportunities described in the Problem and Opportunity Identification section. To begin the formulation process, brainstorming and similar problem solving techniques were used to develop a list of measures and actions that address one or more of the problems or opportunities identified. These initial techniques involved the public, multidisciplinary planners, and various local, county, state, and federal agencies as well as special interest groups. .Next, the list of potential measures and actions was evaluated for the effec- tiveness of each*item in alleviating each identified problem, or realizing identified opportunities. This evaluation is presented in Table C, Effec- tiveness of Measures and Actions. Table C provided a planning tool for preliminary formulation of alternatives. As measures were combined to formulate an alternative for a specific considera- tion, the table provides an indication of the measure's effectiveness in solving a particular problem or realizing a particular opportunity. 20 TABLE C EFFECTIVENESS OF MEASURES AND ACTIONS Waimanalo Watershed, Hawaii MEASURES AND ACTIONS: (4) FAVOKABLE EFFECT (-I AIWIARF EFFECT f") INS 11;N IF I I @ANT F.FFEc r SPECIFIC PROBLEMS AND OPPORTUNITIES As DESCRIBED IN TABLE A W z z W 0 W z X W 8 t@ A ;-@ - -W!@ X . .!; - n z > X: . 0. W V>4 ;@ 6 W I W 0 @ W 00 ' . U W 9 J 99 r! z0 z .4 H. WW W 0 W 0 0 W z W W F@ W. I W .4 3 A. Inadequate irrigation System WIS I.&. Problems with collection system N N N N N N 4 N N N N N b. Problems with distribution system N N N + + + N N N N N 2.a. Inadequate supply - collection system N N N N N N N N N N N b. Inadequate supply - distribution system + + + + + N N N N 3.&. Plant-parasitic nematodes in system + N N N + + + N. N N N N b. Poor water quality + + N + + + + N N N N N 4. Nonpressurized system - energy req uirements N N N N + + N N N N N B. Inadequate Irrigation System - BWS l.a. Domestic system - low farmer confidence N N N N N N N N N N N b. High water costs N N N N N N N N N N N C. Limited availability - high demand N N N N + + N N N C. Opportunity to Utilize Treated Sewage Effluent I.s. Effluent not being used N + N N N N N + N N N N b. Well disposal system nearing capacity N N N N N N N + N N N N 2.a. Land available for irrigation N N N N N N N N N b. Experimental use by Univ. of Hawaii Station N + N N N N + N N D. opportunity to Retain"Prime-Impoitant Farmlands 1.2.a. Prime-important lands could be used for ag. + N N + + + N N N N b. Irrigate more land N N N N + + + N N N N E. Problems With Floodinit I.&. Residential flooding N N N N N + + b., Agricultural flooding + N 4 N + + C. Lack of maintenance - who should do it? N N. N N N N N N + N F. Problem With Waste Disposal N N N N N N N N N N N G. opportunity to Preserve Historical Site 4 N + - N N N N N + 4 N NET SCORE: Number of M minus number of 6 4 2 4 7 8 -1 a 2 4 4 2 JULY 1981 4 Irrigation Considerations Table C shows a combination of measures effective in alleviating many of the problems associated with the existing irrigation systems: a deep storage reservoir, utilization of the sewage effluent, and a piped irrigation system. Consequently, these measures were viewed as a common foundation for several of the alternative plans. While not particularly effective alone, accelerated technical assistance, land treatment, and water conservation measures were considered as vital elements in each irrigation alternati-ve. Water conservation measures such as system management, measuring devices, and control of ditch bank vegetation, were particularly important in the nonstructural alternative. Land treatment meas- ures and accelerated technical assistance were most important in those alterna- tives where previously irrigated cane land and new land were being brought into intensive diversified agriculture. Technical assistance was also important in those alternatives where water quality was improved to minimize its role in transporting nematodes into and within the watershed. This assistance would educate growers and demonstrate cultural practices designed to curtail nematode infestations. Flood Prevention Considerations Flood prevention problems and fhe related measures were, for the most part, not related to irrigation problems, and were treated as separate planning modules. Both a structural and a nonstructural flood prevention modular plan were developed for preliminary formulation. Because topography makes flood prevention dams unfeasible, the only structural alternative was a concrete channel system. However, this modular element was dropped from further consideration when a detailed report prepared for the Sponsors in 1976 (Ref. 19) was updated and projected costs of the channel system far exceeded benefits. The nonstructural systems studied included flood zoning, flood warning, flood proofing, and land treatment. Modification of flood control policies, and management were also investigated. Flood zoning is not covered in an adopted ordinance, but the flood plain identified on the Flood Boundary and Floodway Map (Ref. 13) was used to prepare the proposed regional development plan (Ref. 24). This plan is used to regulate land use and, as such, it results in flood plain management. Flood warning was not considered practical or necessary for the short duration, rapid runoff storms common in Waimanalo. (A flood warning system is currently in use for tsunami hazards.) Elevating structures (or flood proofing) was determined to be practical for only seven residences in the flood damage area, but the measure is not economically feasible. Land treatment and technical assistance could help farmers in solving some of their individual and group onfarm flooding problems with measures such as diversions, waterways, and drains. The most effective nonstructural measure identified was modification of flood control policies and management. This modification would be aimed at obtaining needed improvements to existing ditches, channels, culverts, bridges, etc., and, most importantly, would establish responsibility for accomplishing this work and for performing the operation and maintenance required. In order to determine what improvements and maintenance are needed, and to estimate the costs and environmental effects, a comprehensive study was undertaken by the Sponsors and SCS (under its ongoing program authority). As a result of the decision to make the comprehensive study, this nonstructural measure was dropped from further consideration in the plan. 22 NED Formulation By defi@_1tion, the NED alternative is the one that maximizes net benefits attributable to the project measures. As various alternatives were formulated and evaluated, it became apparent that maximizing the acreages irrigated and minimizing storage cost had the greatest effect on net remaining benefits, As a result, two incremental formulations were set up and evaluated. The first started with the maximum practical storage and the acres that could be i-rri'gated at full supply. The storage was held constant. By lowering the percent of full supply of critical season water that was applied to bananas, more acres of bananas could be grown. This lowering of percents and increasing of acreages was done by 10 percent increments from full supply down to 50 percent--identified as the low limit for banana production in Waimanalo. All changes in returns and costs were calculated to reflect each successive alterna- tive, Acreages of nursery crops and truck crops were held constant throughout because of the extreme high investments and high short-season values that dictate either full water supply production or no production. In this first set of formulations, the 50 percent water supply and maximum acres produced the highest net remaining benefits. The second set of incremental formulations started with the same maximum pracl- tical storage and acreage irrigated as in the first set. In the second set, the initial acreage was held constant and the volume of water storage was varied as percents of full water supply for critical months were varied by 10 percent increments. All changes in costs and returns were calculated to reflect each successive alternative. As costs of storage decreased, net remaining benefits increased for each increment down to 70 percent supply, but then started to decrease as production fell faster than structural cost savings were reduced. In the second set, maximum net remaining benefits were realized at the 70 percent supply, but they were not as high as net remaining benefits from the maximized acres at 50,percent supply for the large reservoir in the first set. Therefore, the first set formulation at the 50 percent water supply iteration is the NED alternative. EQ Formulation The Environmental Quality Plan (EQ) is formulated to reasonably maximize net contributions to the EQ objective--protection and enhance 'ment of environmental quality. Contributions to environmental quality'are favorable changes in the ecological, cultural, and aesthetic attributes of natural and cultural resources that sustain and enrich human life. An EQ plan is formula-, ted to alleviate environmental problems and to take advantage of environmental opportunities that were identified in the early stages of the planning process. The Waimanalo Watershed Plan-EIS identifies one significant EQ problem and two significant EQ opportunities. Problem F (described on Table A) covers--local concerns with solid waste disposal in the rural areas of Waimanalo. Everything from tree trimmings to abandoned cars is dumped along country roads and in ditches degradi,ng the appearance of the area, creating rodent and vector habitat, and the potential for both public health and water quality concerns. Debris dumped in the ditches tends to aggrevate flooding from storm runoff. The alleviation of Problem F was a major objective in formulating the EQ plan.. Opportunity D (described on Table A) covers the national, state, county, regional, and local dedication to retaining prime and important farmlands in agriculture. Hawaii is particularly aware of the finite quantity of this vital resource and ..23 its importance to viable diversified agriculture (Ref. 23). The ecological, cultural, and aesthetic attributes of the resources that sustain and enrich rural life in Waimanalo--an area special to Hawaiians (and therefore to the rest of the country)-- are directly tied to the wise use of prime and important farmlands. The EQ plan was formulated to also take advantage of opportunity D - Opportunity G (described on Table A) covers the potential to preserve and protect those portions of the Waimanalo Irrigation System ditch which may have historical significance. The ditch is under consideration for nomination to the National Register of Historical Places. This opportunity was considered in formulating the EQ plan. EVALUATION OF ALTERNATIVES As a result of the plan formulation process described above, 34 plans were developed to the extent necessary to determine costs, benefits, and effects of each. Different opportunities to contribute to various mixes of the objectives were explored. These tentative plans were discussed with the sponsors and other agencies and at public meetings and workshops. The advantages, dis- advantages, risk and uncertainty of each plan were considered. Generally viability of each alternative plan was determined by considerating four aspects: Completeness - The extent to which an alternative plan accounts for all investments and actions necessary to realize planned results. Effectiveness - The extent to which an alternative plan alleviates the problems and achieves the opportunities identified. Efficiency - The extent to which an alternative plan is most cost effective. Acceptability - The extent to which an alternative plan is accepted by the public and compatible with existing laws, regulations, and policies. The application of this formulation process, including the four aspects described above, effectively identified the seven most successful in solving probl'ems and taking advantage of opportunities. These seven alternatives and the future without are shown and discussed individually as follows: 24 NED WAIMANALO WATERSHED LEGEND frrigated Area Pipeline Potential area for irrigation with treated sewage effluent Open Ditch CA Reservoir o0e BELLOWS A.EB A01rilLANA 60 MG RESERVOIR 0ftft--Wmft dW#%* ANIANI NUI 1 MILE TUNNEL 25 ALTERNATIVE 1 NED Comeonents This alternative consists of accelerating assistance to all WIS irrigators, a storage reservoir, 15.7 miles of pipeline, a separate treated sewage effluent lift pump, reservoir, and pipeline. A change of emphasis would be made in the ongoing land treatment program from "maintenance" to improved irrigation systems. Accelerated technical assistance would be used to assist irrigators in their conversion to sprinkler and drip systems and to design cultural practices to minimize nematode problems. Bananas would be irrigated at 50 percent of the computed water requirement for June to Septem- ber, and acres irrigated would be maximized. Water from Maunawili Watershed would be taken from the tunnel outlet at Aniani Nui Ridge and piped to the reservoir near the mauka end of Mahailua Street. The reservoir would be a deep, off-channel, 60 million gallon excavated structure with an embankment 40 feet high. A gravity pressure pipeline (with some supple- mentary pumping required) would deliver water from the reservoir to the operators. The treated sewage effluent would be pumped from the Waimanalo sewage treatment plant to a storage reservoir at the site of the existing Wing-King Reservoir. The map on the opposite page shows the features discussed above. Costs: 1/ Total project cost = $13,981,000; P.L. 566 share = $6,467,000; H-her = $7,514,000; average annual cost = $1,225,000. Benefits: 1/ Installation of this alternative would provide high quality WIS irrigation water under pressure to 1,134 acres including 79 acres previously irrigated with domestic water. An additional 68 acres would be supplied with treated sewage effluent. Average annual benefits of $2,312,000 would accrue. Effects: The proposed Waimanalo Agricultural Park Plan could be implemented with the irrigation system proposed in this alternative. As a result, the agricultural productivity and the rural character of Waimanalo Valley could be strengthened. The agricultural use of prime and important farmland irrigated by WIS would increase to 1,076 acres with an additional 68 acres irrigated with treated sewage effluent. Problems with solid waste disposal would continue. I/ Values shown do not include costs and benefits associated with the without- project condition. 26 EQ WAIMANALO WATERSHED LEGEND, Irrigated Area i Pipeline area for irrigation Potential with treated Sewage effluGnt Open Ditch Reservoir 'oooool Solid Waste Collection Site BELLOWS A.Es. .......... 0 IP RESERVOIR 4f let jo ANIANI t 4ul TUNNEL ALTERNATIVE 2 EQ components: This alternative consists of accelerating assistance to all WIS irrigators, a storage reservoir, 14.1 miles of pipeline, a separate treated sewage effluent lift pump, reservoir, and pipeline. A change of emphasis would be made in the ongoing land treatment program from "maintenance" to improved irrigation systems.. Accelerated technical assistance would be used to assist irrigators in their conversion to sprinkler and drip systems and to design cultural practices to minimize nematode problems. All crops would receive full irrigation water supply. Irrigation would be directed to prime and important farmlands. The structural facilities are identical to Alternative 1 except that irrigation is not provided for the steeper lands in Area A and the Ag. Park Subdivision. instead, irrigation is provided for additional prime and important farmlands within and adjacent to the irrigation service area. Three solid waste collec- tion stations would be provided. A plan for preservation or protection would be developed with the State Historical Preservation Officer for those portions of WIS ditch which may be determined to have historic value. Other portions of the ditch would be operated by the Sponsors for storm drainage, or they would be abandoned. The map on the opposite page shows the features discussed above. Costs: 11 Total project cost = $12,896,000; P.L. 566 share = $6,153,000; @_ther = $6,743,000;.average annual cost = $1,141,000. Benefits: 11 Installation of this alternative would provide high quality WIS irrigation water under pressure to 890 acres including 79 acres previously irrigated with domestic water. An additional 68 acres would be supplied with treated sewage effluent. All 958 acres irrigated are prime and important farmlands. Average annual benefits of $2,121,000 would accrue. Effects: The proposed Waimanalo Agricultural Park Plan could be modified and implemented with the irrigation system proposed in this alternative. As a result the rural character of Waimanalo Valley would be strengthened. The agricultural use of prime and important farmland irrigated by WIS would increase to 958 acres. Problems with solid waste disposal would be reduced. Those portions of the WIS ditch which may be determined to have historic value would be preserved or protected. 1/ Values shown do not include costs and benefits associated with the without- project condition. 28 NON - STRUCTURAL WAIMANALO WATERSHED LEGEND', IK Irrigated Area 1--l Pipeline Open Ditch CA Reservoir V BELLOWS A.EB. L. . . . . . . OV 0 A q9 .3 - ... ....VI ANIANI NUI TUNNEL 29 ALTERNATIVE 3 NONSTRUCTURAL Components: This alternative consists of repairing the existing distribution system to reduce leakage. The system would be improved to facilitate measurement, improve irrigation scheduling, and improve management. The current rate of technical assistance and land.treatment would be adequate for the estimated needs. Ditch bank vegetation would be removed along the entire 15 miles of ditch and approximately 0.5 miles would be lined where seepage is greatest. Pipe cross- ings would replace 4 flume-trestle stream crossings, and 5 ditch structures would be replaced. Flowmeters would be installed at 36 locations. The map on the opposite page shows the features discussed above. Costs: 11 Total project cost = $497,000; P.L. 566 share = $279,000; i-ther = $218,000; average annual cost = $166,000. Benefits: 1/ Installation of this alternative would provide essentially the same quality water and service to the area currently irrigated. Reliability would be improved, and the savings in water would be used to supplement inade- quate supplies available for lands currently irrigated. Average annual benefits of $382,000 would accrue. Effects: The proposed Waimanalo Agricultural Park Plan could not be implemented with the irrigation system proposed in this alternative. As a result, the conditions similar to the future without project would prevail. With the exception of the proposed lining and the proposed flume and structure replacement, any historic value of the ditch system would not be changed. Problems with solid waste disposal would continue. I/ Values shown do not include costs and benefits associated with the without- project condition. 30 RECOMMENDED WAIMANALO. WATERSHED- LEGEND.' Irrigated Area Pipeline P tential area for irrigation 0 With treated 'iewage 'off luent Open Ditch CA Reservoir, Solid Waste Collection S it' BELLOWS A. E S. 60 MG RESERVOIR 0 A lot ANIAN) NUI TUNNEL 31 ALTERNATIVE 4 RECOMMENDED Comeonents: This alternative consists of accelerating assistance to all WIS irrigators, a storage reservoir, 12.7 miles of pipeline, and a separate treated sewage effluent lift pump, reservoir, and 1.4 miles of pipeline. A change of emphasis would be made in the ongoing land treatment program from "maintenance" to improved irrigation systems. Accelerated technical assistance would be used to assist irrigators in their conversion to sprinkler and drip systems and to design cultural practices to minimize nematode problems. All crops would receive full irrigation water supply. The structural facilities are identical to Alternative 1 except that less pipe is required to service fewer acres, and three solid waste collection stations are provided. A plan for preservation or protection would be developed with the State Histor- ical Preservation Officer for those portions of WIS ditch which may be determined to have historic value. Other portions of the ditch would be operated by the Sponsors for storm drainage or they would be abandoned. The map on the opposite page and Appendix E, Figure 1, the Project Map, show the features discussed above. Costs: !@ Total project cost = $12,798,000; P.L. 566 share = $6,108,000; Et-her = $6,690,000; average annual cost $1,205,000. Benefits: 11 Installation of this alternative would provide high quality WIS irrigation water under pressure to 890 acres, including 79 acres previously irrigated with domestic water. An additional 68 acres would be supplied with treated sewage effluent. Average annual benefits of $2,121,000 would accrue. Effects: The proposed Waimanalo Agricultural Park Plan could be implemented @i@iththe irrigation system proposed in this alternative. As a result 'the agricultural productivity and the rural character of Waimanalo Valley would be strengthened. The agricultural use of prime and important farmlands irrigated by WIS would increase to 905 acres. Problems with solid waste disposal would be reduced. Those portions of the WIS ditch which may be determined to have historic value will be preserved or protected. 1/ Values shown do not include costs and benefits associated with the without- project condition. 32 WITHOUT, PROJECT WAIMANALO WATERSHED LEGEND Irrigate d Area I---I Pipeline Open Ditch Reservoir BELLOWS A.EB. 0 Cr. /r ANIANI NUI lul i MLI TUNNEL 33 ALTERNATIVE 5 WITHOUT PROJECT Components: This alternative is basically a continuation of present condi- tions. It consists of foregoing implementation of the project. It does include some local costs to the Sponsors for obtaining long-term water rights, for improvements over present conditions to the irrigation water collection system i.n Maunawili Watershed, and for operation and maintenance of WIS. As a result of these improvements, additional water is available to supplement inadequate supplies available for lands currently irrigated. The without-project alternative serves as the basis for comparison of the other alternatives. The map on the opposite page shows the without-project alternative. Cost: Total without-project cost = $2,522,000 which is funded 100 percent by other than P.L. 566; average annual cost = $316,000. Benefits: This alternative would continue essentially the same quality water and service to the area currently irrigated. Reliability would be improved. Effects: The proposed Waimanalo Agricultural Park Plan could not be implemented Wi@ththe no-action alternative. The viability of diversified agriculture would decline while pressures to urbanize prime and important farmlands would increase. Problems with solid waste disposal would continue. The existing WIS ditch would remain in service. 34 LINED DITCH WAIMANALO WATERSHED LEGEND Irrigated Area Pipeline Open Ditch - Lined CA Reservoir .0"000, 1100, lu BELLOWS A.EB. 0 JL 4k .Nt ANIANI Nul I MLE TUNNEL 35 ALTERNATIVE 6 LINED DITCH Components: This alternative consi*sts of concrete lining the existing ditches and reservoirs to reduce leakage and water losses to vegetation. Measurement, optimization of irrigation scheduling, and other management facilities and techniques would be installed. The current rate of technical assistance and land treatment would be adequate for the estimated needs. Maunawili and Kailua Reservoirs would be reconstructed to modern safety and operational standards. The storage capacity would remain at approximately 13 million gallons. About 10.2 miles of ditch lining would be installed generally on the present alignments. Water measuring and control facilities would be provided. Improvements affecting those portions of the ditch which may be determined to have historic value would have to be concurred in by the State Historical Preservation Officer. The map on the opposite page shows the features discussed above. Costs: 11 Total project cost = $4,105,000; P.L. 566 share = $2,550,000; RE-her = $1,555,000; average annual cost = $440,000. Benefits: 1/ Installation of this alternative would provide moderately improved water quality and service to 449 acres of cropland within the area currently irrigated. Full irrigation water supply would be provided. Average annual benefits of $775,000 would accrue. Effects: The proposed Waimanalo Agricultural Park Plan could not be implemented @7T`thout extensive modification to reduce its scope. As a result, the future without-project conditions would tend to prevail. Problems with solid waste disposal wou-Id continue. The appearance of the existing ditch system would be changed. I/ Values shown do not include costs and benefits associated with the without- project condition. 36 COMBINED BWS-WIS WAIMANALO WATERSHED A" LEGEND ...... Irrigated Area -4 Pipeline - BWS Open Ditch (::A Reservoir ,o00,0, . ........... o@ B E LL(YwS A.EB AVK4&AWA VrWEFO CW VL V. 11o ..-'WATEI@ Z T I MILE ANIANI NUI TUNNEL 37 ALTERNATIVE 7 COMBINED WITH BWS Components. This alternative consists of the complete transfer of all water rights and collection and distribution facilities from WIS to the City and County of Honolulu, Board of Water Supply (BWS), the domestic water supply agency for Oahu. The current rate of technical assistance and land treatment would be adequate for the estimated needs. Only ground water would be utilized in this totally enclosed system. About 2 million gallons of regulation storage would be provided by tanks. All facilities would be installed to meet standards and requirements for potable water. The existing ditch system would be abandoned except where the Sponsors preserve or protect those portions which may be determined-to have historic value. The map on the opposite page shows the features discussed above. Costs: 1/ Total project cost = $13,895,000; P.L. 566 cost = $6,395,000; 6-ther = $7,500,000; average annual cost $1,235,000. Benefits: 11 Installation of this alternative would provide top quality water and continuous service to the area currently irrigated. Acreage irrigated would remain the same, limited by the capability of the small storage capacity to handle peak irrigation demands. Average annual benefits of $585,000 would accrue. Effects: The proposed Waimanalo Agricultural Park Plan could not be implemented ;i'lththe combined irrigation-potable water system proposed in this alternative. Urbanization of the prime and important farmlands would be facilitated by the expanded potable water supply and distribution system. Problems with solid waste disposal would continue. Portions of the ditch which may be determined to have historic value would be preserved or protected. 1/ Values shown do not include costs and benefits associated with the without- project condition. 38 PIPE SERVICE. TO EXISTING WIS USERS WAIMANALO WATERSHED, ,LEGEND Irrigated Area Pipeline Open Ditch .... .. CA Reservoir BELLOWS A.EB. FL 14 G F EkE VOIR ANIAM NUI I OLE TUNNEL 39 ALTERNATIVE 8 PIPE-SERVICE TO EXISTING USERS Components: This alternative consists of installing a reservoir and 10.2 miles of gravity pressure pipe system to irrigate the area now served by WIS. A change of emphasis would be made in the ongoing land treatment program from 11maintenance" to improved irrigation systems. Accelerated technical assistance would be used to assist irrigators in their conversion to sprinkler and drip systems. All crops would receive full irrigation water supply. This system would require a 14 million gallon excavated reservoir near the mauka end of Mahailua Street. A gravity pressure pipeline (with some supple- mentary pumping required) would deliver water from the reservoir to the opera- tors. A plan for preservation or protection would be developed with the State Historical Preservation Officer for those portions o *f WIS ditch which may be determined to have historic value. Other portions of the ditch would be operated by the Sponsors for storm drainage or they would be abandoned. The map on the opposite page shows the features discussed above. Cost s: 11 Total project cost = $4,970,000; P.L. 566 share = $2,880,000; iTt-her = $2,090,000; average annual cost $515,000. Benefits: 1/ Installation of this alternative would provide high quality WIS irrigation water under pressure to 528 acres including 79 acres previously irrigated with domestic water. Average annual benefits of $1,635,000 would accrue. Effects: The proposed Waimanalo Agricultural Park Plan could not be implemented ;;@ithout extensive modification to reduce its scope. Viability of current agricultural operations would be enhanced, and the future would be an improvement over the future without-project condition. Problems with solid waste disposal would continue. Those portions of the WIS ditch which may. be determined to have historic value would be preserved or protected. I/ Values shown do not include costs and benefits associated with the without- project condition. 40 CANDIDATE PLANS The next step, after formulating alternative plans, was to identify the alternative plans that could be considered as candidates for a recommended plan. The NED,-EQ, and nonstructural plans as well as the future without- proj,ect are required to be included as candidate plans.'. The alternative plans described'as Lined Ditch, Combined With BWS, and 1. mE@ Service to Existing Users were not designated ca'ndidate plans because they did not adequately alleFl-ate identified problems'or take advantage bf'identified opportunities. Evaluation focused on four aspects of an alternative plan-- completeness, effectiveness, efficiency, and acceptability. The evaluation also considered the risk and uncertainty involved with each plan'. Each of the the three p-lans failed to allow implementation of the State's Waimanalo Agricul- tural Park Plan. The small storage capacities proposed increased the risk of crop damages from droughts. The Lined Ditch alternative failed to solve the Problems With water quality and quantity. @ombined With BWS provided top quality water exceeding the quality requirements for most crops, but a high degree of uncertainty exists for many irrigators concerning agriculture's long range access to a potable water system. The proposal is the'least cost-effective of all plans considered. Piped Service to Existing Users is essentially a scaled-down versi:on of the recommended plan, and it was unacceptable because did not adequately alleviate the problems and take advantage of the opportunities. The candidate plans continued to be refined and are displayed on the following table, Summary Comparison of Candidate Plans, Table D. 41 TABLE D SUMMARY COMPARISON OF CANDIDATE PLANS Waimanalo Watershed, Hawaii ALTERNATIVE I - ALTERNATIVE 2 - ALTERNATIVE 3 - ALTERNATIVE 4 - NAT;ONAL ECONOM IC ENVIRONMENTAL QUALITY NONSTRUCTURAL RECOMMENDE D. OEV LOPMENT (NED) (EQ) Project Investment $13,982,000 $12,896,000 $ 497,000 $12,798,000 NED ACCOUNT Adverse, Annualized $ 1,225,000 $ 1,140,000 $ 166,000 $ 1,205,000 Beneficial, Annualized 2,312,000 $ 2,121,000 $ 382,000 $ 2,121,000 Met beneficial $ 1,087,000 $ 981,000 $ 216,000 $ 916,000 41 RED ACCOUN'r Positive Effect, Annualized Region ' $ 4,150,000 $ 4,089,000 $ 460,000 $ 4,D89,OOO Rest of Nation $ 520,000 $ 509,000 - $ 55,000 $ 509,000 Negative Effect, Annualized Region $ 699,000 $ 647,000 $ 144,000 $ 714,000 Rest of Nation $ 526,000 $ 493,000 $ 22,000 $ 498,000 EQ ACCOUNT Beneficial Ag. Use of Prime and Add 616 acres. Add 430 acres. No change. Add 377 acres. Important Farmlands Visual Attribute - Appear- No change in visible 3 solid waste collec- No change in visible 3 solid waste collection ance of Valley Floor garbage. Addition tion sites will reduce garbage. No change in sites will reduce visible of 674 acres of visible garbage. Addi- irrigated diversified garbage. Addition of 430 irrigated diversified tion of 430 acres of agriculture. acres of irrigated diversi- agriculture will in- irrigated diversified fied agriculture will in- crease variety and agriculture will in- crease variety and visual visual contrast. crease variety and constrast. visual constrast. JULY 1961 TABLE D SUMMARY COMPARISON OF CANDIDATE PLANS (Continued 2)' Waimanalo Watershed, Hawaii ALTERNATIVES ALTERNATIVE I ALTERNATIVE 2 - ALTERNATIVE 3 - ALTERNATIVE 4 - iiO-N.S RECOMMENDED NATIONAL ECONOMIC ENVIRONMENTAL QUALITY TFi5-CTURAL COIPAR SON FA ORS @l EVELO`PMENT CNFD) (EQ) EQ ACCOUNT (conti.) Beneficial Historical Sites WIS Retain historically Retain historically Entire ditch system Retain historically Ditch significant reaches of significant rea,'hes of retained. significant reaches of abandoned ditches. abandoned d itche abandoned ditches. Waimanalo Stream Minor improvement. Minor improvement. No effect. Minor improvement. Water Quality Adverse 12 Known Archeological I may be affected. I may be affected. None affected. I may be affected. Sites Visual Attribute - Reservoir will be Reservoir will be No change. Reservoir will be Appearance of Foothills major contrast in major contrast in major contrast in viewshed. viewshed. viewshed. OSE ACCOUNT Beneficial Preserve the Rural Will add 62 farming Will add 40 farming No change in number Will add 40 farming Character of Waimanalo units. units. of farming units. units. Population Estimates for 9,450 and 12,000 - Ag. 9,450 and 12,000 Ag. 9,450 and 12,000 - No Ag. 9,450 and 12,000 - Ag. Year 2000 and Year 2020 Park Plan may encourage Park Plan may encourage Park Plan. Park Plan may encourage 10,000 for Year 2020. 10,000 for Year 2020. 10,000 for Year 2020. Adverse Low - Probability Hazard New reservoir - 77 New reservoir - 77 Existing reservoirs 21 New reservoir - 77 Resulting from Structural residences could be residences could be residences could be residences could be Failure of Embankment inundated. inundated. inundated. inundated. Energy Required to Operate 150,000 KwHr/YR 135,000 KwHr/YR Minor 150,000 KwHr/YR the System (Pumping) Energy Required to Build 700 billion BTU's- 668 billion BTU's- 29 billion STIT's. 660 billion BTU's. the System NOTES: Interest rates - all plans evaluated at 7 3/8 percent interest. JULY 1981 Period of analysis - all plans evaluated over 50 years. Price levels - current 1980 price levels except for crops where average 1977-1979 prices were used. Dollars values shown* 'do not include @osr, and benefits associated with the without-project condition.' 7. 41 PROJECT INTERACTION The following table displays the relationship of the candidate plans to existing or expected Federal and non-Federal projects where significant economic, environmental, or physical interactions exist. TABLE E - INTERACTION WITH OTHER PROJECTS WAIMANALO WATERSHED, HAWAII OTHER FEDERAL AND NONFEDERAL PROJECTS WAIMANALO WATERSHED Sewage Plant. CE Flood Control CANDIDATE PLANS Waimanalo Sewage Treatment U.S. Army CE Kaneohe Plant - effluent disposal Kailua Flood Control and system uses 3 wells - Allied Purposes - construc- 128 FG-/YR current rate tion displaced 45 acres of wells nearing capacity bananas - State Dept. of Ag. considered this a serious economic and social impact upon growers. Alt. 1 NED 78 R_G/YR effluent used Irrigated bananas in Wai- for irrigation manalo increased by 402 acres. Irrigation at 50% of full water requirements. Alt. 2 EQ 78 FG/YR effluent used Irrigated bananas in Wai- for irrigation manalo increased by 159 acres. Irrigation at 10OYo of full water requirements. Alt. 3 No interaction No interaction NONSTRUCTURAL Alt. 4 - 78 FG/YR effluent used Irrigated bananas in Wai- RECOMMENDED for irrigation manalo increased by 159 acres. Irrigation at IM of full water requirements. Alt. 5 WITHOUT No interaction No interaction PROJECT 44 RISK AND UNCERTAINTY The degree of risk and uncertainty involved in each alternative plan was. considered throughout the planning process and adjustments w'ere'made in,the plans to reduce risk and uncertainty. Risk in alternative plans for'Waimanalo Watershed includes the severity and frequency of droughts, the hazards assoc- iated with a sudden structural failure of.the reservoir embankment, and the likelihood of reinfestations by plant-parasitic nematodes.. Uncertainty includes the unknown future in the choice of crops planted, the economics of producing and selling those crops, and the timing of damaging natural disasters. The drought risk would be lowest for Alternatives 1, 2, and 4 where large storage capacities are included to provide dry season water. Many years of hydrological data were used tolaccurately predict specific frequencies of water supply levels. In the highly unlikely event of a structural failure, hazards would be greatest with Alternatives 1, 2, and 4 because of the 60 mil lion gallon storage reservoir. The risk of failure occurring probably would be greatest with the existing Kailua Reservoir used in Alternatives 3 and 5, but the resulting damage would be.less than for the 60 million gallon@reservoir. The large storage reservoir would be designed as a class (c) hazard structure which is the most conservative design criteria used by SCS. It would be an off-channel structure not signifi- cantly affected by storm runoff. The risk of nematode reinfestation by irrigation water is greatest with Alterna- tive 3. The deep reservoir used in Alternatives 1, 2, and 4 would kill most plant-parasitic nematodes by denying them oxygen. The piped distribution system would reduce the risk for contamination of the irrigation water (Ref. 21). Although, in a free society, some uncertainty will always exist in the choice of crops to be planted, the cropping patterns predicted were based on extensive farmer interviews and consultations with interested agencies. Current normalized prices of.commodities and production impacts are used to minimize uncertainty in agricultural benefits. The State is committed to increased production of the fruit and vegetables consumed in Hawaii. They are presently meeting only one-third.of their requirement and.importing the remainder (Ref. 23 and 27). 45 COMPARISON OF CANDIDATE PLANS The Sponsors selected Alternative No. 4 as the recommended plan. The selection was based on the various evaluations described previously--effects on problems, opportunities and environmental factors; completeness, effective- ness, efficiency, and acceptability; risk and uncertainty; and input from individuals, groups, and agencies as described in the Consultation and Public Participation section. Alternative No. 1 NED would do an excellent job in facilitating implementaTi@onof the propos@_dWaimanalo Agricultural Park Plan. The major fault with this plan is its unacceptability to farmers and the Sponsors and, as such, it may not be implementable. It would require providing the banana growers only 50 percent of the full water supply required during the high-demand period (summer). The water saved would be used to bring additional acreage and operators into production. This would result in reduced income to existing banana growers. The reduced supply distributed over more acres would have a higher risk of drought damage to bananas than the recommended plan. A detailed explanation of the incremental analysis used in formulating the NED plan can be found under the subtitle, "NED Formulation" in the Formulation of Alternatives section. Alternative No. 2 @_Q would do an excellent job in meeting the environ- mental objectives of Waimanalo, but it is not in direct agreement with the proposed Agricultural Park Plan. This alternative irrigates different areas than the Agricultural Park Plan proposed. The emphasis is placed on irrigating prime and important farmlands and does not support irrigating other lands. Alternative No. 3 Nonstructural would fail to adequately alleviate the identified problems with WIS. The ir-rigation system remains basically the same as it would be in the future without project. Management opportunities, water quantity, system reliability, and water quality would be only slightly improved . This alternative also would fail to take advantage of the identified opportunities. No increase would be made in the agricultural use of prime and important farmlands. Alternative No. 4 Recommended would do the best job in alleviating identified problems and in taking advantage of identified opportunities. Irrigation water quantity, quality, and system reliability would not be exceeded by any other candidate plan. There are 244 acres less irrigated cropland than in Alternative No. 1, but every acre would receive a full supply, and the risk of drought damage would be less. There are only 53 acres less prime and important farmlands in agriculture than in Alternative No. 2, and that EQ opportunity is 94 percent realized. The EQ problem with solid waste disposal would be alleviated in this alternative. The EQ opportunity to preserve those sections of the ditch which may be determined to have historic value would be the same as in Alternative No. 2. 46 RECOMMENDED PLAN GENERAL The recommended plan, Alternative 4, includes features of both the NED plan and the EQ plan. This plan is closely integrated with the State's proposed Waimanalo Agricultural Park Plan and recognizes certain actions by DLNR to acquire long term water rights and upgrade the water collection system in Maunawili Watershed as absolutely essential to the accomplishment of both plans. The P.L. 566 part of the watershed plan is limited to actions within Waimanalo Watershed and includes the following: Waimanalo Irrigation System (WIS) improvement, sewage effluent irrigation system, solid waste collection sites, land treatment, and technical'assistance. PURPOSE The purposes of this plan are improvement of agricultural water management through modernizing an antiquated irrigation system; use of treated sewage effluent for irrigation; preserving and enhancing environmental quality by retaining prime and important farmland in agricultural use; protecting and preserving portions of the WIS ditch which may be determined to have historic value; and improving health and aesthetics by providing adequate solid waste collection sites. PLAN ELEMENTS Waimanalo Irrigation System improvement starts at the east portal of the Aniani u'--R-'l-dge Tunnel where water from Maunawili Watershed is picked up in a 16-inch pipe and carried 1.8 miles under gravity pressure to a fenced 60 million gallon, reinforced concrete lined reservoir at the mauka end of Mahailua Street (P*Iates I and 2, Appendix D and Photo 15). Visual treatment will be applied to the reservoir site to minimize adverse visual effects. Flow into the reservoir will be screened and discharged to minimize aeration. Releases will be from near the bottom of the reservoir. This arrangement will tend to control plant-parasitic nematodes by reducing the available oxygen. The delivery system below the reservoir will be a closed, pressurized pipe system, 10.9 miles long, ranging from 24 inches to 6 inches in diameter (Table 3B). There will be a metered outlet at each irrigation turnout. At certain critical locations along the upper mainline there will be booster pumps to provide sufficient sprinkler pressure to users with land above the gravity pressure contours. Treated Sewage Effluent Irrigation System will consist of a separate pump-reservoir-pipeline system 1.4 miles long operated by WIS to use treated sewage effluent to irrigate crops allowed by health regulations, such as bananas, orchard crops, and certain nursery crops. A pump station at the Waimanalo Sewage Treatment Plant will pump the effluent through a 12-inch pipeline to a two-cell 3.0 million gallon effluent storage reservoir to be constructed at 47 the Wing-King Reservoir site. A relift pump at the reservoir will deliver effluent to lands above the reservoir. All delivery lines will be 12-inch pipe (Plate 4, Appendix D). All effluent will be applied by furrow irrigation on farmlands shown on Figure 1, Appendix E. Solid Waste Collection Sites will be graded and surfaced to facilitate all weather use and maintenance, and they will be screened from view. The three sites will be equipped with heavy-duty dumpsters (Plate 5, Appendix D). The general location of the sites is shown in Figure 1, Appendix E. Land Treatment includes planning and application of resource management systems by individual farmers to protect the resource base and achieve project benefits. The SCS provides planning and application assistance to farmers through the Windward Oahu Soil and Water Conservation District. Conservation plans are recorded decisions made by the land users combining the technical information available from the SCS with the farmers' desires and knowledge of the land and crops. Such plans are useful when several related practices are to be applied and the sequence and/or timing are related. Plans are also useful to the farmers in budgeting and scheduling the application of practices and to the SCS in scheduling technical assistance. Conservation practices needed to apply the resource management systems are listed on Table 1. Land which has not been farmed in the last few years will be cleared. Surface water removal systems carry rainwater from the land without erosion or damage using such practices as diversions and waterways. Irrigation systems will use the most practical and efficient application methods--sprinklers, drip, and surface sytems. Irrigation water management systems are irrigation methods the farmer uses to apply water needed by the crop without waste or erosion and consider such factors as water holding capacity of the soil, moisture requirements of the crop, and rainfall. Soil management systems will assure that the physical condition of the soil does not deteriorate from cultivation, compaction due to traffic, and applying water to supplement natural rainfall. This combination of practices is know as a conservation cropping system. Technical Assistance is provided through the Windward Oahu Soil and Water Conservation District to farmers in the project area. SCS assistance under the present program is 1.4 person-years per year. It is estimated th 'at 1.7 person-years per year SCS assistance will be needed to assist farmers plan and apply the needed conservation practices during the four-year project instal latio n period. The accelerated technical assistance heeded is 0.3 person-year per year over the ongoing program. P.L. 566 funds for accelerated technical assistance by the.University of Hawaii and the Cooperative Extension Service are directed to the control of nematodes by providing onfarm assistance coupled with an intense information program. Landrights needed for installation of both reservoirs are owned by the State and include 11 acres for the 60 million gallon reservoir and 2.6 acres for the sewage effluent reservoir. Landrights for the pipeline systems are owned by the State or the City and County where pipelines will be in road rights-of-way. Solid waste collection sites will be developed on approximately 0.2 acr6,State or City and County land. 48 RESERVOIR SAFETY The location of the proposed 60 million gallon reservoir near the mauka end of Mahailua Street is upslope from residences and various other facilities. The SCS has taken two courses of action to minimize the risks to public safety associated with the reservoir. Thefirst step' was to assign the earth embankment (or dam) the most severe [email protected] Class (c). Class (c) dams receive rigorous and thorough foundation and soils investigations. They are designed using the safest procedures and in accordance with the most rigid criteria. Construction will be inspected continuously and various quality indicators such as material strengths, densities, and internal pressures in the foundation and embankment will be monitored. The most likely causes of a sudden structural failure were considered. The reservoir embankment will not be constructed across a stream. Consequently, the operation of the reservoir is largely independent of storm activity and related stream flooding, and it is not subject to overtopping. However, a concrete emergency spillway structure is included in the design of the reservoir to safely pass flows that would be generated by the probable maximum precipita- tion (44 inches in 24 hours) if it occurred over the approximately 6 acres occupied by the reservoir. Operational problems with the reservoir structure could involve negligent operation, malfunctioning valves or gates, or vandalism. These problems would not pose a significant hazard to public safety. Pipe flow into the reservoir can be diverted into Waimanalo Stream, and the reservoir can be drained using the gravity pipe system. A catastrophic natural event--an earthquake--was.determined to be the most likely cause of a sudden structural failure although the possibility of such a failure is extremely remote. To evaluate earthquake hazards a seismic assess- ment was conducted for this structure which is in Seismic Zone 1 (moderately low). It was determined that there have been 2 earthquakes with Richter magnitude 4 or greater (4.0 and 4.1) since 1900 within a 60 mile radius of the reservoir. All structural elements will be designed for the earthquake forces required in Seismic-Zone 1. The second step to minimize the risks to public safety was to evaluate the adverse effects of a sudden structural failure. The major hazard would'result from the sudden, rapid and uncontrolled release of water associated with a breach of the structure. A breach analysis identified the courses a flood wave would follow and its depth. Elevations of specific residences and streets were checked. The water depth would be about 7 feet above street level at the stream crossing on Waikupanaha Street near Kakaina Street, the first crossing downslope from the reservoir. As the flood wave moves downslope and widens, the depth decreases to about 2 feet above street level at the intersection of Kakaina and Mekia Streets. The area flooded by the wave is shown in Appendix C, Area Subject to Flooding in the Event of Structural Failure. Table F presents the findings of the evalua- tion. Table F also presents the finding of a similar evaluation for the existing Kailua Reservoir which is retained in the future without-project alternative. Kailua Reservoir will no longer be a part of the irrigation system under the recommended plan, and the Sponsors will modify it to reduce the hazard. 49 TABLE F - RESIDENCES AND AREAS SUBJECT TO FLOODING IN THE EVENT OF A STRUCTURAL FMI-LURE Waimanalo Watershed, Hawaii Item Without Project Recommended Plan (Kailua Reservoir, Existing) (Proposed Reservoir). Residences Flooded 21 77 (Number) I/ Area Flooded Residential Zone 0acres 17.9 acres Commercial Zone 0acres 0.9 acres Agricultural Zone 31.6 acres 212.4 acres Parks 3.5 acres 54.2 acres 1/ The number of residences with water above the first floor is based on a June 1981 field examination of the flooded area. Few, if any, additional residences are anticipated within the area flooded over the 50-year life of the project. Population increases will be in the residential areas planned for growth. MITIGATION No losses of wildlife habitat will occur as a result of-implementing this plan, and therefore no mitigation has been included. The U.S.'Fish and Wildlife Service and the State Division of Forestry and Wildlife participated with SCS in this determination. 50 PERMITS AND COMPLIANCE All activities related to the construction and operation of the facilities described in the Recommended Plan section will be accomplished in full com- pliance with all county, state and federal requirements. County (City and County of Honolulu) requirements are as follows: GRADING AND GRUBBING 1/ City and County of Honolulu Ordinance No. 3968 DPW - (Bill No. 101, Draft 3:1972) State requirements are as follows: 1. HISTORIC PROPERTY 21 Hawaii Sessions Laws, Act 104, 1976. DLNR - 2. SEWAGE EFFLUENT HRS Chapter 342, Environmental Quality, Part III: Water Pollution, and Dept. of Health Regulations, Chapter 38: Sewage Treat- 3/ ment and Disposal Systems. DOH - 3. SOLID WASTE HRS Chapter 343, Environmental Quality, Part V: Solid Waste Pollution, and Dept. of Health Regulations, Chapter 46, Solid 3/ Waste Management Control. DOH - Federal requirements for permits and other entitlements are shown on Table G on the following page. 1/ City and CouFfyof Honolulu, Department of Public Works Yl State of Hawaii, Department of Land and Natural.Resources State of Hawaii, Department of Health 51 TABLE G - COMPLIANCE OF THE RECOMMENDED PLAN WITH WRC-DESIGNATED ENVIRONMENTAL TT-ATUTES' Waimanalo Watershed, Hawaii FEDERAL POLICY COMPLIANCE 1. Archeological and Historic Preservation Full compliance Act, 16 U.S.C. 469, et seq. 2. Clean Air Act, as amended,.42 U.S.C. Not applicable 1857h-7, et seq. 3. Clean Water Act (Federal Water Pollution Full compliance Control Act), 33 U.S.C. 1251, et seq. 4. Coastal Zone Management Act, 16 U.S.C. Full compliance 1451, et seq. 5. Endangered Species Act, 16 U.S.C. Full compliance 1531, et seq. 6. Estuary Protection Act, 16 U.S.C. Not applicable 1221, et seq. 7. Federal Water Project Recreation Act, Not applicable 16 U.S.C. 460-1(12), et seq. 8. Fish and Wildlife Coordination Act, Not applicable 16 U.S.C. 661, et seq. 9. Land and Water Conservation Fund Act, Not applicable 16 U.S.C. 4601-4601-11, et seq. 10. Marine Protection, Research and Sanctuary Not applicable Act, 33 U.S.C. 1401, et seq. 11. National Environmental Policy Act, Full compliance 42 U.S.C. 4321, et seq. 12. National Historic Preservation Act, Full compliance 16 U.S.C. 470a, et seq. 13. Rivers and Harbors Act, 33 U.S.C. Not applicable 403, et seq. 14. Watershed Protection and Flood Prevention Full compl.iance Act,.16 U.S.C. 1001, et seq. 15. Wild and Scenic Rivers Act, 16 U.S.C. Not applicable 1271, et seq. 1/ NOTES: Full Compliance -Having met all requirements. Partial Compliance -Not having met some of the requirements that normally are met. Noncompliance -Violation of a requirement of the statute. Not Applicable -this plan does not involve'elements that require compliance. 52 COSTS Installation costs for the Recommended Plan include: cost of accelerated land treatment needed to achieve the irrigation benefits; cost of construction (base year 1980) including 10 percent contingency costs; engineering services for design; land and water rights needed for installation and operation of project measures; associated land clearing and land building cost; and project administration costs for construction supervision and inspection (Tables 1, 2, and 2A). Annualized costs include amortization of installation costs at 7-3/8 percent for the 50-year life of project period or for shorter periods for certain land treatment items; and operation, maintenance, and replacement (OM&R) costs for structural measures. OM&R costs for land treatment are accounted for in costs and returns for irrigated crops. Annualized costs of $1,205,000 attributable to irrigation improvements and $7,000 attributable to solid waste collection sites are shown as adverse effects under the NED part of Table 4. Land treatment costs include installation and technical assistance costs of conservation cropping systems, storm runoff diversions, grassed waterways, irrigation systems, onfarm irrigation pipelines, irrigation water management, and land clearing necessary to achieve the benefits from improved quantity and quality of irrigation water. Table 1 shows costs to be incurred during the four-year installation period in excess of the ongoing rate of that type of land treatment in the watershed. Land treatment costs include $20,000 P.L. 566 funds for accelerated technical assistance and $596,000 other funds under ongoing programs. Construction costs include engineer's estimates plus contingency costs for the following: water collection system improvement outside the watershed--no P.L. 566 funds and $500,000 other funds; irrigation storage reservoir--$2,485,000 P.L. 566 funds and $2,485,000 other funds; irrigation pipeline system--$1,425,000 P.L. 566 funds and $1,425,000 other funds; modification of the WIS ditch for surface runoff disposal--$25,000 P.L. 566 funds and $25,000 other funds; sewage effluent pumps, storage reservoir, and pipelines--$205,000 P.L. 566 funds and $205,000 other funds; solid waste collection sites--$30,000 P.L. 566 funds and $30,000 other funds; for a total of $4,170,000 P.L. funds and $4,670,000 other funds. Engineering services costs include the direct costs of engineers and others required for design-level investigations, engineering design and construction specifications. Total engineering services are estimated to cost $831,000 in P.L. 566 funds and $33,000 in other funds. Landrights costs include the value of the land resources used for project installations and any costs of public utility protection or relocation. Total landrights costs are estimated at $740,000 other funds (no P.L. 566 funds). Water rights will be secured by the Sponsors and are considered as existing under the future without-project condition. Project administration costs include the costs of preparing invitations to bids, administering contracts, inspection, and overhead costs of project instal- lation including legal opinions where needed. Project administration costs are estimated at $1,087,000 P.L. 566 funds and $651,000 other funds. 53 Total installation of structural measures is estimated to cost $6,088,000 P.L. 566 funds and $6,094,000 other funds for a total of $12,182,000. INSTALLATION AND FINANCING The planned sequence for installing the structural improvements during the first year includes:. design and construction of the pipeline from Aniani Nui Ridge Tunnel to the 60 million gallon storage reservoir, construction of that reservoir, construction of the 1.5 million gallon sewage effluent reservoir, and a start on the delivery systems. Construction during the second year will include the delivery systems and the solid waste disposal sites. The planned sequence for installing land treatment would be phased over four years with the first two years concentrating on preparation of those lands in the Agricultural Park Subdivision and Area "A." The conversion of sprinkler irrigation to drip and development of contour furrow irrigation for the sewage effluent will be delayed until the 'new delivery systems are nearing completion. This sequence should provide the least disruption of the cropping,operations and farm production. Table H presents the planned expenditure of funds during the project installation. TABLE H SCHEDULE OF OBLIGATIONS Waimanalo Watershed, Hawaii Year Measure P.L. 566 Funds Other Funds Total Funds 1 Reservoirs & Pipelines $3,040,000 $ 2,800,000 $ 5,840,000. Water Collection System 500,000 500,000 Land Treatment 160,000 160,000 2 Complete Reservoirs, Pipelines & Solid Waste Sites 3,048,000 2,757,000 Land Treatment 160,000 160,000 3 Contracted Technical - Assistance - 20,000 -- 20,000 Land Treatment - -- 160,000 160,000. 4 Land Treatment - 153,000 153,000 TOTAL $6,108,000 $6,690,000 $12,798,000 Responsibilities DLNR is responsible for the installation of all structural measures, obtaining landrights and water rights, protection of public utilities, and coordination with other state and county agencies. The Windward Oahu Soil and Water Conservation District will assume the leadership in the installation and maintenance of land treatment measures, using agreements with individual farmers. Final decisions on land treatment measures rests with the landowner or operator. Technical assistance will be provided by SCS under the ongoing' program and with P. L. 566 funds. 54 Landrivhts and Utilities Acquisition of all lands, easements, or rights-of-way shall be made in compliance with the Uniform Relocation Assistance and Real Property Acquisition Policies Act of 1970, P.L. 91-646, and appropriate USDA and federal regulations. These provide that in cases where landrights are not obtained by donation or land exchange, every reasonable effort will be made to acquire real property rights by negotiation. Prior to the initiation of negotiations, an appraisal of the fair market value of the real property interest will be made by a qualified land appraiser. Most, if not all, landrights are already state or city and county property. Several public utilities both buried and above ground exist within the planned project. At the 60 million gallon storage reservoir, an overhead, double-pole supported, electric powerline crosses the mauka edge of the construction site. Work near this line will require extreme caution and must be coordinated with the utility company. Throughout the delivery system,' numerous pipeline crossings of buried and above.-ground utilities will be encountered. These include rural electric powerlin4s and telephone cables; BWS delivery lines, existing WIS ditches, pipelines, and water control structures; Waimanalo Sewage Collection System; and roads, streets, culverts, and bridges. Changes of existing utilities or protection inplace which are made necessary by the works of improvement will be the responsibility of DLNR. Costs of these changes or protection shall be considered landrights costs. Costs. of changes or protection to existing irrigation facilities made necessary by the works of improvement shall be considered construction costs and be cost-shared at the same rate as the works of improvement. Contracting 5--stallation of the structural works of improvement will be under a locally awarded contract., Contracts for the construction of structural measures will be let on competitive bids. SCS will prepare all contract documents. DLNR will be responsible for all contracting and for coordinAting with the SCS during installation. DLNR is also responsible for establishing a financial management system, including financial reporting requirements, meeting the requirements listed in the Federal Management Record 74-7. SCS will contract for the P.L. 566 funded technical assistance described in this plan. Financing Federal assistance for installing the structural works of improvement as described in this plan will be provided under the authority of the Watershed Protection and Flood Prevention Act, Public Law 566, 83rd Congress, 68 Stat. 666, as amended (P.L. 566). Under this authority SCS will provide: (1) eng- ineering services, including surveys, site investigations, designs, and prepara- tion of plans and specifications; (2) project administration, including review of engineering plans prepared by others, government representatives, construction surveys, necessary inspection services during construction, and contract adminis- tratioh; and (3) technical assistance to farmers and others. The Department of Land and Natural Resources (DLNR) is a legally constituted department of the Hawaii State government. As such, DLNR has the power to 55 borrow money for financing the installation of this project, the power of eminent domain, and the power to charge fees for repayment of borrowed funds and payment of operating expenses. Structural installation costs other than those allocated to Public Law 566 funds will be the responsibility of DLNR. State appropriated funds will be used to pay the local share of structural installation costs. Donations of land, easements, labor, material, equipment, services, or money by the Sponsors or others may, as eligible, be used to reduce the local share of project installation costs. Conditions for Providing Assistance The following condMons shall be met before issuance of invitations to bid on any portion of construction: 1. The necessary landrights and water rights will be acquired by DLNR which agrees to use its authority to litigate if necessary. 2. DLNR will ensure that all necessary permits required for project construc- tion are obtained. Contractors will be required to follow regulations to prevent sedimentation and pollution of stream waters during construction. Dust control during construction will be required. Contractors will also be required'to provide protection against the effects of excessive noise exposure. All SCS safety requirements for construction will be strictly observed. 3. Mutual agreement shall be reached between DLNR and SCS on the schedule for construction and on plans and specifications. Contracts for works of improvement shall be mutually satisfactory and inaccordance with requirements of the DLNR and in agreement with SCS technical and administrative requirements. 4.- DLNR Will ensure full conformance with city and county, state, and federal laws and regulations. Reasonable evidence of such conformity shall be provided to the mutual satisfaction of all parties. 5. Agreements for the operation and maintenance of all reservoirs, pipeline systems, and solid waste collection sites shall be agreed to in writing by DLNR and SCS. 6. Structural improvements on the WIS collection system in Maunawili Watershed are required for the proper functioning of the total WIS system and shall be completed, or they shall be under construction and scheduled for completion prior to completing installation of the structural elements in this plan. Cultural Resources One archeological site is in the vicinity of the Agricultural Park Subdivision. An environmental impact statement (EIS) is being,prepared by the State covering development of the subdivision in the proposed Waimanalo Agricul- tural Park. It will consider the effects and disposition of this site. SCS and the State Historic Preservation Officer have submitted the Waimanalo Ditch System for nomination to the National Register of Historic Places and are awaiting a formal determination of eligibility. SCS will follow the procedure found at 7 CFR 656 regarding the future of the ditch system. If cultural resources are discovered during construction, appropriate notice will be made to the Secretary of Interior and the Hawaii State Historic Preserva- tion Officer and SCS procedures found at 7 CFR 656 will be followed. ..56 OPERATION, MAINTENANCE, AND REPLACEMENT General The operation, maintenance, 'and replacement of structural measures will be the responsibility of DLNR. An operation and maintenance agreement will be executed prior to signing a project agreement in accordance with the SCS publication, "Hawaii Watershed Operation and Maintenance Handbook. The operation and maintenance agreement will include,specific provisions for retention and-disposal of property acquired or improved with Public Law 566--financial assistance. An operation and maintenance plan will be prepared.for all structural measures. The total annual cost for operation,,maintenance and replacement is $148,000. Operation .Reservoir inflow and releases will be monitored and adjusted by WIS to meet project demands for irrigation water. In the 60 million gallon storage reservoir, water depth will be generally maintained greater than 10 feet above the outlet to assist in controlling plant-parasitic nematodes that may have eqtereO the reservoir. Outflow from the reservoir into the irrigation delivery [email protected],ill.belmonitoreid for nematode content periodically throughout the irrigatfon season. The drain valve assembly at the intersection of Waimanalo Stream and Waikupanaha Street is available for disposal of reservoir inflow as well as al.drainage facility for the reservoir itself. The sewage effluent storage reservoir will be operated to meet project demands for irrigation water without overflow into the adjacent stream under routine operating conditions. Close coordination with the Waimanalo Sewage Treatment Plant will be required. Backflow for the sewage effluent storage reservoir is provided at the sewage plant pump sump.with a manually controlled valving system. The gated outlet facility at the reservoi.r will allow storage water to be drained into the existing injection wells at the sewage plant. Special attention will be required for the operation of both reservoirs to ensure that the full supply of planned water storage will be available during the irrigation season (critical water-short months are June through September). DLNR will operate or arrange for the operation of the solid waste collection sites. Maintenance The 60 mil-lion gallon storage reservoir and the sewage effluent reservoir will be maintained by WIS. The principal routine work items are servicing and maintaining slide gates, maintaining reinforced concrete structures, maintaining structural backfill, removing debris, cleaning debris and algae from trashracks, repairing fencing, maintaining the reservoir lining and drainage system. WIS will also maintain the distribution system keeping all pipeline structures, pumps, irrigation turnout structure, meters, valves, screens, and pipe protection devices in serviceable condition by maintenance or repairs as needed during the life of the project. WIS will mai'ntain the capacity of the reservoir diversion channels and spillways by clearing debris and undesirable vegetative growth. Poor stands of vegetation or areas destroyed by erosion, will be reestablished and, if necessary, eroded areas will be restored before reseeding. Particular emphasis will be placed on the condition of landscaping vegetation, the vegetation at the two reservoirs, on the immediate small areas upstream, and within the diversion channels. 57 A reasonable vegetation establishment period (not to exceed one year) will be allowed after initial plantings. The need for maintenance will.be determined by inspections. Inseection An inspection to determine operation, maintenance, and replacement needs will be conducted during or immediately after the initial filling of the reservoirs. There will be an inspection annually and after any major storm or earthquake. An SCS engineer will assist in conducting structural measure inspections. A qualified SCS employee will assist in conducting inspections of land treatment and vegetation. DLNR will maintain a record of all maintenance inspections, any maintenance required together with the schedule for completing it, and when completed, the cost of the maintenance. A copy will be submitted to SCS. Reelacement Major repair as a result of severe storms or other causes, and replace- ment of worn or deteriorated items with a useful life shorter than the 50-year life of the project, will be provided by the DLNR. The following items have an estimated useful life of approximately 25 years: Slide gates on the reservoir and the control structures Pump and motors Trashracks and debris racks Traveling screen at the reservoir inlet Valves, vents, pressure relief valves, etc. Meters, flow control valves 58 TABLE 1 ESTIMATED INSTALLATION COST Waimanalo Watershed, Hawaii Estimated Cost (Dollars) Total P.L. 566 Funds Total Installation Cost Item Unit Number (SCS) Other Funds Total ,LAND TREATMENT' 0 0 Conservation Cropping System Acres 314 Feet 20,000 40,000 40,000 Diversion 6,000 6,000 Grassed Waterway Acres 12 Irrigation System No. 52 127,000 127,000 Irrigation Pipeline (On-farm) Feet 26,000 288,000 288,000 Irrigation Water Management Acres 450 .0 0 Acres 314 128,000 128,000 Land Clearing 3/ Man/Years 0.3 20,000 7,000 27,000 Technical Assistance 20,000 596,000 616,000 Subtotal Land Treatment STRUCTURAL MEASURES: CONSTRUCTION: Water Collection System All All 0 500,000 500,000 Improvements 2,485,000 2,485,000 4,970,000 Irrigation Storage Reservoir No. I Irrigation Pipeline System Miles 14.1 1,425,000 1,425,000 2,850,000 Old Irrigation Ditch Modification All All 25,000 25,000 50,000 Sewage Effluent Pumps, Pipeline system and Storage Reservoir All All 205,000 205,000 410,000 Solid Waste Collection Sites No. 3 30,000 30,000 60,000 Subtotal Construction 4,170,000 4,670,000 8,840,000 ENGINEERING SERVICES: 831,000 33,000 864,000 Subtotal Engineering All All LAND AND WATER RIGHTS: Subtotal Land Rights All All 0 740,000 740,000 PROJECT ADMINISTRATION All All 1,087,000 651,000 1,738,000 TOTAL STRUCTURAL 6,088,000 6,094,000 12,182,000 TOTAL PROJECT 6,108,000 6,690,000 12,798,000 JULY 1981 1/ Price base 1980 il Federal agency responsible for assisting in installation of works of improvement 'S1 Includes contracted technical services in nematode control and trickle irrigation TABLE 2 - ESTIMATED COST DISTRIBUTION IRRIGATION AND ENVIRONMENTAL ENHANCEMENT STRUCTURAL MEASURES Waimanalo Watershed, Hawaii (Dollars) Installation Costs - PL-566 Funds Installation Cost - Other Funds Total Construc- Engi- Project Total Construc- Engi- Land Water Project Total Installed Item tion neering Admin. PL-566 tion neering Rights!/ Rights Admin. Other Cost STRUCTURAL MEASURES Water Collection System Improvements: 3/ 4/ - - - - 500,000 33,000 67,000 600,000 600,000 (1,000,000) (67,000) (400,000) (133,000) (1,600,000) (1,600,000) Irrigation Storage Reservoir: 2,485,000 500,000 650,000 3,735,000 2,485,000 550,000 350,000 3,385,000 7,020,000 0 Irrigation Pipeline System: 1,425,000 280,000 370,000 2,145,000 1,425,000 50,000 200,000 1,675,000 3,750,000 Old Irrigation Ditch Modi- fication For Surface Runoff Disposal: 25,000 5,000 10,000 40,000 25,000 25,000 65,000 S wag:':!fluent Pumps, Pipe line eM and Storage Reservoir; 205,000 40,000 50,000 295,000 205,000 130,000 30,000 365,000 660,000 Solid Waste Collection Sites: 30,000 6,000 7,000 43,000 30,000 10"000 4.000 44,000 87,000 TOTAL STRUCTURAL MEASURES 4,170,000 831,000 1,087,000 6,088,000 4,670,000 33,000 740,000 651,000 6,094,000 12,181,000 GRAND TOTAL 6,088,000 6,oq4,ooo 12,182,000 I/ Price base 1980. JULY 1981 1/ Opportunity cost value of land rights owned by local sponsors or acquired for project plus protection.of utilities. 3/ Associated cost necessary to the project but notcost-shared because they occur outside the watershed boundary. 41 Item in parenthesis will be installed in the future even without the project and are not added to project costs. Water rights costs are annual costs of $30,000 capitalized at 7-3/8% for 50 years. TABLE 2A - COST ALLOCATION AND COST-SHARING SUMMARY IRRIGATION AND ENVIRONMENTAL ENHANCEMENT STRUCTURAL MEASURES Waimanalo Watershed, Hawaii (Dollars) 1 1 Cost Allocation Cost-Sharing Purpose PL-566 Other Environ. Environ. Environ. Item irrigation Enhance. Total Irrigation Enhance. Total Irrigation Enhance. Total Water Collection Syste improvements! 37- Construction 500,000 500,000 500,000 500,000 Engineering 33,000 33,000 33,000 33,000 Project Admin. 67,000 67,000 67,000 67,000 Subtotal 600,000 600,000 600,000 600,000 Irrigation Stor ge Reservoir- con!truction 4,970,000 4,970,000 2,485,000 2,485,000 2,485,000 2,485,000 E gineer. 500,000 500,000 500,000 500,000 n lng 4/ Land Rights - 550,000 550,000 550,000 550,000 Project Admin. 1@000,000 1,000,000 650,000 650,000 350,000 350,000 0% Subtotal 7,020,000 7,020,000 3,635,000 3,635,000 3,385,000 3,385,000 Irrigation Pipeline System: Construction 2,850,000 2,850,000 1,425,000 1,425,000 1,425,000 1,425,000 Engineering 4/ 280,000 280,000 280,000 280,000 50,000 Land Rights - 50,000 50,000 50,000 Project Admin. 570,000 570,000 370 000 370,000 200,00 200@00 _T, -750,000 2-,-0-7 ' Subtotal 3,750,000 5,000 T-6-75-M 1,675,000 1,675,000 Old Irrigation Ditch Modification: Construction 50,000 50,000 25,000 25,000 25,000 25,000 Engineering 5,000 5,000 5,000 5,000 Project Admin. 10,000 10,000 10,000 10,000 Subtotal 65,000 65,000 40,000 40,000 25,000 25,000 Sewage Effluent Pumps, Pipeline System and storage Reservoir: Construction 410,000 410,000 205,000 205,000 205,000 205,GOO En:ineerine 40,000 40,000 40,000 40,000 La d Rights 130,000 130,000 130.000 130,000 Project Admin. 80.00 80,000 50,000 50,000 30,000 Subtotal 660,000 660,000 295,000 295,000 365,000 T6TM Solid Waste Collection Sites: Construction 60,000 60,000 30,000 30,000 30,000 30,000 Engineering 6,000 6,000 6,000 6,000 Land Rights 4/ 10,000 10,000 10,000 10,000 Project Admin. 11,00 11,00 7.000 7,000 4,000 4,000 Subtotal 87,000 87,0001 43,000 43,000 44,000 44,000 TOTAL 12,095,000 87,000 12,182,0001 6,045,000 43,000 6,098,000 16.050,000 44,000 6,094,000 I/ Price base 1980 JULY 1981 Cost-sharing: Construction items 50-50; engineering and administration about 5/6-1/6, PL-566 and other funds respectively 3/ Associated costs necessary to the project but not cost-shared because they occur outside the watershed boundary 4/ opportunity cost value of land rights owned by local sponsors or acquired for project plus protection o f u tilities TABLE 3A - STRUCTURAL DATA EXCAVATED RESERVOIRS WITH PLANNED STORAGE CAPACITY Waimanalo Watershed, Hawaii Storage & Sewage Item Unit Regulating Effluent Ponds Class of Structure C NA Seismic Zone 1 NA Controlled Drainage Area ac. 5.2 0.8 (Reservoir Surface) Elevation Crest Inflow (Submerged) ft.(msl) 242.0 87.0 Assumed Elev. Elevation Top of Dam ft.(msl) 311.7 96.5 11 Elevation - Irrigation Storage ft.(msl) 308.7 94.5 Pool Elevation Crest of Ungated ft.(msl) 308.7 95.5 Spillw@y Maximum Height of Fill (Top of ft. 40 3 Dam to Original Ground) Volume of Fill cu. yd. 197,600 3.,358 Maximum Depth of Excavation ft. 37 17.5 Volume of Excavation cu. yd. 230,400 29,341 Reservoir Capacity - Irrigation Pool RG 60 2 @ 1.5 ea. ac. ft. 184.1 4.6 Surface Area - Irrigation Pool ac. 5.2 2 @ 0.8 ea. Inlet Pipeline System Design iG/D 4.7 2.6 Ungated Spillway Design Freeboard Design Rainfall Volume (FH) in. 44 (PMP) 12 (P25) Runoff Volume (FH) in. 44 12 Storm Duration hr. 24 24 Maximum Reservoir W.S. ft.(msl) 309.9 95.5 Assumed Elev. Elevation Type Drop Spillway Crest Length ft. 12.5 12-in.-diameter Capacity at Top of Dam Elev. cfs 200 3.3 Routed Flow @ Maximum Res. cfs 52 0.4 W.S. Elev. Diversion for outside Reservoir Drainage Area - Drainage Area ac. 6.3 9.8 Frequency - Design % PMP 4 Storm Duration hr. 24 24 Runoff Peak Flow cfs 200 13 JULY 1981 62 TABLE 3A - STRU CTURAL DATA (Continued - 2) EXCAVATED RESERVOIRS WITH PIANNED STORAGE CAPACITY Waimanalo Watershed, Hawaii Storage & Sewage Item Unit Regulating Effluent Ponds Type Rocky Alluvium Material Bottom Width ft. 10 2 Velocity of Flow fps 5.9 3.8 Slope of Channel ft./ft. .005 .01 Irrigation & Drain Outlet Pipe Elevation Crest Outlet ft.(msl) 245 PUMP Conduit Diameter in. 24 12 JULY 1981 63 TABLE 3B - STRUCTURAL DATA PIPELINE SYSTEM Waimanalo Watershed, Hawaii Max. Staticv Minimum irrigation 4/ Design Pressure Outlet Pressure Booster Pumps Required Pipeline Location Type Length Diameter Flow @ Max. W.S. @ Probable Max. Flow For Sprinkler Pressure ft. in. gpm psi psi no. RESERVOIR SUPPLY Tunnel to reservoir AC 9,700 16 3,250 94 NA NA 4.7 RG/D IRRIGATION DISTRIBUTION On Mahailua St. from reservoir AC 2,680 24 3,250 82 39 1 to Waikupanaha St. On Waikupanaha St. from PVC 1,660 14 2,230 82 50 - Mahailua St. to Kakaina St. On Waikupanaha St. from PVC 1,600 14 1,300 94 48 - Kakaina St. to Kumuhau St. on Waikupanaha St. fr- PVC 675 12 1,010 94 NA - 0% Kumuhau to outlets of Area "A!' 4- and Ag. Park Subdivision oa Waikupanaha St. from PVC 1,960 14 1,875 84 50 2 Mahailua St. to Kaulukanu St. On Waikupanaha St. from PVC 1,840 14 1,375 80 47 2 Kaulukanu St. to Mokulama St. On Waikupanaha St. from PVC 1,760 14 1,760 83 48 1 Mokulama St. to Ahiki St. On Waikupanaha St. from PVC 940 10 460 83 48 - Ahiki St. to end of line PVC 4,800 8 220 95 57 - JULY 1981 TABLE 3B - STRUCTURAL DATA (Continued - 2) PIPELINE SYSTEM Waimanalo Watershed, Hawaii V Max. Static.!/ Minimum Irrigationg Design Pressure Outlet Pressure Booster Pumps Required Pipeline Location Type Length Diameter Flow @ Max. W.S. @ Probable Max. Flow For Sprinkler Pressure ft. in. gpin psi psi no. IRRIGATION DISTRIBUTION (conti.) On Kakaina St. makai from PVC 2,420 8 200 104 57 Waikupanaha St. to Mahailua St. On Kakaina St. from Mahailua St. PVC 800 6 130 115 74 to end of line On Kakaina St. mauka from PVC 2,320 12 150 78 0 1 Waikupanaha St. to end of line PVC 1,020 8 150 50 - - On Kumuhau St. makai from PVC 2,940 8 150 112 64 Waikupanaha St. to Mahailua St. On Kumuhau St. from Mahailua St. PVC 860 6 150 117 81 0*1 to end of line ;.n On Mahailua St. from Kumuhau St. PVC 960 6 150 114 78 to end of line Area "A" - mauka of PVC 1,800 12 300 80 0 1 Waikupanaha St. PVC 2,400 8 150 55 - - Ag. Park Subdivision PVC 1,725 10 460 90 44 3 PVC 2,775 6 150 115 44 - On Mooiki St. makai from PVC 1,240 6 150 101 92 Waikupanaha St. to end of line On Kaulukanu St. makai from PVC 2,460 6 150 112 60 Waikupanaha St. to end of line JULY 1981 TABLE 3B - STRUCTURAL DATA (Continued - 3) PIPELINE SYSTEM Waimanalo Watershed, Hawaii 3/ Max. Static Minimum Irrigation 41 Design Pressure Outlet Pressure Booster Pumps Required Pipeline Location Type Length Diameter Flow @ Max. W.S. @ Probable Max. Flow For Sprinkler Pressure ft. in. gpm psi psi no. IRRIGATION DISTRIBUTION (conti.) On Kaulukanu St. mauka from PVC 11650 12 218 75 2 1 Waikupanaha St. to end of PVC 800 8 150 54 3 - all lines PVC 540 6 150 33 5 Lateral makai from Waikupanaha PVC 950 6 150 78 59 St. between Kaulukanu St. and Mokulama St. On Mokulama St. from Waikupanaha PVC 2 320 6 ISO 112 65 St. makai to end of line On Makakalo St. from Mokulama PVC 1,050 6 150 108 72 St. to end of line a% From Makakalo St. makai to PVC 950 6 G% end of line 150 111 75 On Ahiki St. from Waikupanaha PVC 3,440 10 415 122 82 St. to Hihimanu St. On Hihimanu St. PVC 11500 8 150 123 84 PVC 2,500 8 290 129 90 SEWACE USE AREA From pump at sewage plant PVC 3,450 12 1,150 25 NA I to reservoir From reservoir to areas PVC 4,000 12 450 15 irrigated with treated 0 sewage effluent I/ With maximum water surface in reservoir at elevation 317.0 3/ @ 5 gpm/ac or 150 gpm (min.), whichever is greater JULY 1981 To pump from sewage reservoir to "on-farm" outlet for With minimum water surface in reservoir at elevation surface irrigation 260.0 TABLE 4 - PROJECT EFFECTS Waimanalo Watershed, Hawaii NATIONAL ECONOMIC DEVELOPMENT Beneficial Effects Adverse Effects Components Measure of Effects Components Measure of Effects (Average Annual)Y (Average Annual)2/ A. Value to users of increased A. The value of resources outputs of goods and services: required for the project: 1. Irrigation $1,996,000 1. Project outlays 2. OM&R foregone 3/ 125,000 a. Irrigation reser- voirs and pipeline systems - Project instal- S918,000 lation OMLR $148,000 a% b. Accelerated land 47.000 treatment c. EQ construction (S 7,000) components 2. Other project costs a., Interest during 49,000 construction 5/ b. Water collection Total Beneficial Effects $2,121,000 system improvements Net Beneficial Effects $ 916,000 occurring outside of watershed - Installation cost S 38,000 B:C = 1.8:1.0 OMLR $ 5,000 Total Adverse Effects $1,205,000 I/ Price base - 1980 current normalized. JULY 1981 7/ Amortized over 50 years @ 7 3/8 percent interest. T/ OMLR no longer needed because of project action. A/ Solid waste collection sites related to surface drainage. aesthetics. and health. Costs not charged against NED beneficial effects. 5/ Construction period of 2 years with approximately equal investment in each year and quarter year. Compounded interest @ 7 3/8 percent ($648,000) is then amortized over 50 years. TABLE 4 - PROJECT EFFECTS (Continued 2) Waimanalo Watershed, Hawaii REGIONAL ECONOMIC DEVELOPMENT Beneficial Effects Adverse Effects Components Measure of Effects Components Measure of Effects State of Rest of State of Rest of Hawaii Nation Hawaii Nation (Average Annual) (Average Annual) 21 A. Value of increased output A. Value of resources con- of goods and services to tributed from within users residing in the the region to achieve region: the outputs: 1. Irrigation $3,580,000 0 1. Project outlays 2. Additional wages to $ 500,000 -$500,000 a. Irrigation reser- agricultural workers voirs and pipeline 011 systems - 00 3. Additional OM&R wages $ 9,000 -$ 9,000 Project installation $463,000 $462,000 OM&R $148,000 0 B. External economies from nil b. Accelerated land $ 34,000 $ 13,000 supplying agricultural treatment production inputs 2. Other project costs Total Beneficial Effects $4,089,000 4509,000 a. Interest during $ 26,000 $ 23,000 construction b. Water collection systems improvements occurring outside of watershed - Installation costs $ 38,000 0 OM&R $ 5,000 c. External diseconomies Total Adverse Effects $714.000 $498,000 1/ Price base - 1980 current normalized. JULY 1981 7/ Amortized over 50 years @ 7 3/8 percent interest. S1 Estimated by WRC Guideline 5 Regional Multipliers, January 1977, "Direct Effect" components for fruits, vegetables, and nursery products. TABLE 4 - PROJECT EFFECTS (Continued - 3) Waimanalo Watershed, Hawaii ENVIRONMENTAL QUALITY Beneficial Effects Adverse Effects Components Measure of Effects Components Measure of Effects A. Aesthetics 1. Project output will make A. Aesthetics 1. Removal of vegetation causing available regional funds and a temporary unsightly landscape resources that can be used to during construction. enhance the rural appearance of 145 farms on 1,252 acres. 2. Removal of surface irrigation system removes visibility of 2. Provide irrigation water to water on the landscape. an additional 430 acres of diversified agriculture, 3. Irrigation reservoir and creating more color contrast associated works will be a on the landscape. major contrast in the viewshed. 3. Create 2 reservoirs with total surface area of 7 acres which diversify the landscape from viewpoints above the valley. 4. Improve the appearance of the landscape by providing solid waste sites which are screened from view. JULY 1981 TABLE 4 - PROJECT EFFECTS (Continued 4) Waimanalo Watershed, Hawaii ENVIRONMENTAL QUALITY Beneficial Effects Adverse Effects Components Measure of Effects Components Measure of Effects B. Ecological 1. Improves fish and wildlife B. Ecological 1. Forty additional farm units may Attributes habitat and food by freeing Attributes introduce additional dogs and spring water to flow down cats into the area which will Waimanalo Stream. have an adverse effect on the present wild animals. 2. Orderly solid waste collection sites will reduce chance of stream pollution. C) C. Cultural 1. Identifies and protects C. Cultural 1. Unknown buried archeological Attributes archeological and historical Attributes sites may be disturbed during sites. construction before their significance is realized. JULY 1981 TABLE 4 - PROJECT EFFECTS (Continued 5) Waimanalo Watershed, Hawaii OTHER SOCIAL EFFECTS Beneficial Effects Adverse Effects Components Measure of Effects Components Measure of Effects A. Urban and Community 1. Create 100 low to medium A. Urban and Community 1. Annualized local costs Impacts income jobs in agriculture. Impacts of project total $714,000 These costs are borne 2. Create regional income by family income classes benefits of $4,089,000 as follows: distributed by family income costs as follows: Percent of Estimated Percent of Estimated Family Population Percent of Family Population Percent of Income Class in Class Benefits to Class Income Class in Class Benefits to Class Less than $10,000 36.6% 20% Less than $10.000 36.6% 5% $10,000-$20.000 37.3% 25% $10,000-$20,000 37.3% 20% More than $20,000 26.1% 55% More than $20,000 26.1% 75% B. Life, Health, 1. Reduces safety hazards B. Life, Health, 1. Creates flood hazard and Safety to WIS maintenance and Safety to 77 houses and about employees. 350 people from sudden failure of off-stream reservoir. 2. Reduces flood hazard to 21 houses and about 95 people from sudden failure of Kailua Reservoir. 3. Reduces potential health hazards by improved facilities for solid waste. C. Long-Term 1. Encourages maintenance C. Long-Term 1. Commits 13.6 acres to Productivity of 1,199 acres of impor- Productivity the two reservoirs. tant farmland in ag. use. 2. Commits 0.2 acre to solid waste collection sites. D. Energy Requirements 1. Makes use of gravity 0. Energy Requirements 1. Installation: pressures to save 660 billion BTU's. pumping energy. 2. Operation: JULY 1981 150,000 KwHr/YR. -- EFFECTS OF RECOMMENDED PLAN GENERAL This section describes the economic, environmental, and social effects of the planned project and discusses four aspects of these effects. The first aspect covers features determined to have significant effect on specific resources and resource attributes. Table B - Inventory and Analysis of Resources and Forecasting lists the significant items as determined by fhe 'scoping process. The second aspect expands on comments made in Table 4, Project Effects. The third explains the degree or extent to which the recommended plan alleviates theproblems and takes advantage of the opportunities listed in Table A, Problems and Opportunities. The last aspect deals with specific resources that are recognized by federal policies. Table H - Hfects of the Recommended Plan on Resources of Principal National Recognition lists the Fy--pesof resources, the specific policy, and the measurement of effects. SIGNIFICANT EFFECTS The recommended plan involves four of the six project actions covered by Table B: pipelines in place of ditches; new reservoir; irrigation with sewage effluent; and irrigation of more land. These project actions have a medium to high significance to decisionmaking for 11 of the 17 resources listed in the table as follows: Prime and important farmlands under irrigation are increased by 377 acres. Waimanal al o stream qu.2,@t will tend to be improved by no longer using Kailua Reservoir in the irrigation system. Spring water generated on upper Waimanalo Stream will now flow unimpeded. The replacement of open ditches by pipelines will eliminate ditch flushings as a source of temporary stream contami- nation. Ground water quantity in the alluvial zone may tend to be reduced as leaking ditches and reservoirs are replaced and irrigation efficiencies increase. Irrigation with treated sewage effluent introduces the opportunity for effluent to move into the alluvial ground water. Municipal water (BWS) used for agricultural production is estimated to decrease from 71 to 56 million gallons per year. Irrigation water quantity (WIS) delivered to the farm will increase from 128 to 548 million gallons per year. This increase will deliver a full water supply to the 449 acres presently irrigated (often with less than full supply) and to an additional 441 acres (actually 430 acres when BWS and sewage are considered). 72 Irrigation water quality will be improved by the reduction of mineral and organiF-matter transported, reduction of the opportunity for contamination by agricultural chemicals, and the almost complete elimination of@plant-porasitic nematodes. Visual resources will be improved by utilizing the solid waste collection sites, the increased number of farming operations from 105 to 145, and by the additional 430 acres in irrigated farmland. There will be a loss in visual quality when some portions of the ditch are abandoned. Character of human environment is enhanced as desired in state and local plans by the strengthening of agriculture in Waimanalo. The 40 new farms will involve approximately 100 additional people in agriculture. Population is forecast to expand to 12,000 by the year 2020. By strengthening agriculture, the recommended plan will tend to encourage a 2020 population of approximately 10,000 (Ref. 1). One Archeological site in the vicinity of the proposed Ag Park Sub- division may be directly affeE-t-ed by the implementation of the State's proposed Agricultural Park Plan. It will be evaluated and covered by the State's'EIS for the Ag Park Subdivision. Sites that May be uncover.ed by project construc- tion operations will be handled in accordance with SCS procedures as detailed at 7 CFR 656. Historical sites may include portions of the antiquated WIS ditch system. IT has-been proposed for nomination to the National Register of Higtoric Sites and appropriate actions will be taken in accordance with SCS procedures (7 CFR 656). PROJECT EFFECTS SHOWN IN TABLE 4 Table 4 separates the beneficial and adverse effects of the recommended. plan into four separate accounts--National Economic Development, Regional Economic Development, Environmental Quality, and Other Social Effects. National Economic Development (NED) T11 @beneficial effects in the NED account stem from improved irrigated crop production as a result of structural and land treatment measures. These measures provide a more dependable and higher quality irrigation water supply. WIS will have an improved pressurized pipeline delivery system that accommodates highly efficient drip or sprinkler application. WIS will have a separate system for furrow irrigation with treated sewage effluent. The beneficial effects of the project are the increases in net returns above production costs (over and above net returns that would accrue under the future without-project condition) and are estimated at $2,121,000 per year. Adverse effects in the NED account attributable to irrigation include the Tn@nualized costs 'of reservoirs, pipeline systems, and land treatment that would be greater with the project than under the future without-project condi- tion. Annualized costs include amortization of installation costs plus increases in operation and maintenance costs. Adverse effects of solid waste collection sites as shown in parentheses are the amortized costs of those installations. and are not :harged against NED'bene'ficial effects. Total adverse effects are c estimated at $1,205,000 per year. 73 Total beneficial effects of $2,121,000 minus total adverse effects of $1,205,000 provide net beneficial effects of $916,000 per year. Beneficial effects divided by adverse effects provide a B:C ratio of 1.8:1.0. Regional Economic Development (RED) Beneficial effects in the RED account recognize that the annual net benefits to the nafTonal economy will actually accrue to the resident economy of Hawaii and not to the rest of the nation. There will be additional benefits to the region in the form of income to agricultural workers and to WIS opera- tion and maintenance workers who might be working in other states if not employed in Hawaii (transfer or displacement benefits). Adverse RED effects include the annualized local share of structural installation and Tand treatment; operation, maintenance and replacement costs borne by Hawaii; and the annualized costs of structural measures and land treatment borne by the rest of the nation. Emphasis is on the relative subsidy of the project by the rest of the nation and the benefit accrual to Hawaii. Environmental Quality (EQ) N@neficial effects in the EQ account will occur with project instal- lation., The appearance of the area will be enhanced by several features of the recommended plan. There will be improvements to houses, barns, yards, and fields as a result of increased net incomes to the farmers. The additional 430 acres of irrigated land in diversified crops such as bananas, truck crops, and nursery stock will increase color contrast resulting in a more pleasing visual impression. The new reservoirs will create diversity from the surrounding lands when viewed from the mountains or from aircraft. The recommended plan provides for three containerized solid waste disposal sites located off the roads and screened by w"etation. Use of these sites will improve the appearance of the area by reducing the present practice of discarding waste materials along rural roads and in ditches. Spring water flowing into Kailua Reservoir is now stored with ditch water from Aniani Nui Tunnel. Water is released down the Waimanalo Stream for scheduled irrigations or when the reservoir fills from heavy rainfall. These flows tend to reduce stream water quality by flushing debris from the ditches into the stream. The recommended plan would not divert ditch water into Kailua Reservoir and as a result the occasional reductions in quality would not occur. The recommended plan provides for the identification of significant historical and archeological resources. Those that are identified will be preserved or protected according to plans that will be developed with the State Historical Preservation Officer in accordance with SCS procedures (7 CFR 656). Adverse environmental quality effects from the installation of the project include removal of natural vegetation in construction areas, causing a temporary visual scar on the landscape, movement of construction equipment through the rural area--temporarily disrupting tranquility. The present irrigati.on system presents fleeting glimpses of water in the ditches on irrigation days, creating an interesting visual impression. The recommended plan eliminates the use of ditches to transport irrigation water and thus loses this visual asset. Removal of vegetation along abandoned portions of the WIS ditch will cause some reduction in visual diversity on the valley floor. 74 The increase in irrigated land will result in 40 additional farm units with some increase in dogs and cats. These domestic animals will have an adverse effect on wildlife. Construction activities, such as pipe installation, may disturb unidentified buried archeological sites. Other Social Effects Te-ne-f-if-c-Mal effects (to urban and community impacts) include the creation of 100 new jobs in agriculture that probably would be filled from the Waimanalo community. The regional gross income benefits of $4,089,000 would largely be distributed among family income classes in proportion to those involved in agriculture. Though Waimanalo farms are small, family net income level is often quite good because of high-value crops and family labor in highly intensive cropping. Over half of the benefits from irrigation will accrue to families with income over $20,000 per year. Benefits to life, health, and-safety include an important reduction of safety hazards by replacing unsafe antiquated wooden flumes with buried pipe siphons, and replacing open ditches with closed pipe systems eliminating the need for continual herbicide application. Kailua Reservoir will no longer be a part of the irrigation system, and the remote threat of damage to 21 houses by the flood from a structural failur'e would be reduced. Health hazards will be reduced by improved solid waste collection sites that encourage more orderly garbage disposal. Benefits to long-term productivity will accrue from the project encouraging the maintenance of 1,199 acres of prime and important farmland in agricultural use. This occurs because profitable irrigated farming is better able to compete against urbanization for the use of land than is marginal farming or dry pasture. Benefits from energy conservation will be 'realized by replacing onfarm sprinkler pumps with gravity pressures for most lands now irrigated. Booster pump energy to irrigate some of the additional acres at higher elevations and pump energy to use the sewage effluent will be required. Adverse effects to the community include the annualized local costs of the project which will be borne by local residents in proportion to the user fees and income taxes paid. This concentrates the payment of the local costs on families with higher incomes. Adverse effects to life, health and safety include the hazard to 77 houses from the remote threat of a sudden failure of the 60 million gallon reservoir on the mauka. end of Mahailua Street. Massive earthquake damage would be the most likely-event that might create such failure. Adverse effects to long-term productivity would occur from the commitment of approximately 13.6 acres for the reservoirs and approximately 0.2 acre for solid waste collection sites. Adverse energy effects include the consumption of 660 billion BTU's to fabricate and install the project measures and 150,000 kWh/yr for operation. EFFECTIVENESS OF THE RECOMMENDED PLAN Table A describes 7 general and 13 specific problems or opportunities with water and related land resources in Waimanalo Watershed. The following 75 discussion relates directly to the lettered general problems or opportunities and the numbered specific problems or opportunities in Table A: A.L Undependable supply and operation The-sponsors have agreed that as a part of the future without-project condition they will acquire long-term water rights and make structural improvements in the Maunawili Watershed collection system. They also agreed, as a condition to implementing this plan, to make improvements in Maunawili to enhance water quality. The recommended plan will alleviate the physical and operational problems with.the distribution system in Waimanalo Watershed. A.2. Inadequate amount of water to irrigate 1,873 acres of irrigable Waimanalo farmland The-recommended plan will irrigate a total of 1,252 acres at full SuIpply. A.3. Poor.water quality limits use and mana@ement opportunities The replacement of the open ditch distribution system with p sure pipelines and collection system improvements eliminate the major sources of contamination to irrigation water. The deep storage reservoir will serve as a control to any plant-parasitic nematodes in the system by restricting their oxygen supply. The water as delivered to the farm will be sprinkler quality, and the nematode problem will be greatly reduced to easily manageable levels. Drip systems will require standard onfarm filtering. The treated sewage effluent will be satisfactory for surface irrigation of crops allowed by health regulations such as bananas, orchards, and certain nursery crops. B.I. BWS primarily a domestic water supply system The -dependence on BWS for irrigation is reduced from 71 to 56 million gallons per year. The new WIS facilities provided by the recommended plan will meet Waimanalo's agricultural water needs although some users may choose to use domestic water for irrigation if it is avai,lable. C.1. Opportunity to use 128 'RG/YR of treated sewage effluent The recommended plan will use 78 million gallons per year of treated sewage effluent for irrigation. C.2. Irrigable state lands close to the sewage treatment plant Treated sewage effluent will be conveyed to approximately 68 acres of state controlled land including the University of Hawaii, College of Tropical Agriculture, Waimanalo Experiment Station. In addition to partially meeting the station's irrigation water requirements, the treated sewage effluent provides an opportunity for experimentation with its use on various crops. D.1. and 2. WIS service to 449 acres of prime and important farmlands out of 2,174 acres available The recommended plan will irrigate 837 acres of prime and important farmlands with WIS water and an additional 68 acres with sewage effluent. (BWS will irrigate 294 acres for a total of 1,199 acres.) E.1. Flooding problems from frequent storm events The recommended plan does not significantly alleviate the nuisance flooding. The recommended plan will make minor unevaluated improvements by providing facilities for solid waste collection. Solid waste discarded along the roads clogs ditches and culverts. The abandoned WIS ditch system will be modified and 'maintained as necessary to continue to operate as a storm runoff drainage system. 76 During plan formulation, the Sponsors requested that SCS make a study and prepare a report addressing the need for improvements and modifications in the existing drainage system. Costs and potential environmental effects will be included and needs will be ranked. This report will be used by the Sponsors to request changes in policies or laws-as necessary to alleviate specific problem E.1.c. Lack of Maintenance. F.1 Solid waste disposal problems The recommended plan provides facilities, which the Sponsors will operate and maintain, for solid waste collection sites. The Sponsors will work with local groups to encourage use of the sites rather than roadside dumping. G.1 Opportunity to preserve or protect historically significant portion of WIS ditches If portions of the WIS ditches submitted for nomination to the National Register are determined to have historic value, those portions will be preserved or protected in accordance with a plan developed with the State Historical Preservation Office (SCS procedures are at 7 CFR 656). EFFECTS ON NATIONALLY RECOGNIZED RESOURCES .Certain federal policies and laws recognize specific types of resources. These policies and laws impose specific requirements for analysis of the effects of a recommended plan as shown in Table I. In addition to the ten "Types of .Resources" shown in Table I, there may be some localized reduction in quality of alluvial ground water as a result of irrigation with treated sewage effluent. Ground water resources are recognized nationally in the Safe Drinking Water Act, as amended (42 U.S.C. 300f et seq.). 77 TABLE I EFFECTS OF THE RECOMMENDED PLAN ON RESOURCES OF PRINCIPAL NATIONAL RECOGNITION Waimanalo Watershed, Hawaii Principal Sources of- Types of Resources National Recognition Measurement of Effects .1. Air quality Clean Air Act, as amended No effect (42 U.S.C. 1857h-7 et seq.) 2. Areas of particular Coastal Zone Management Act No effect concern within the OF 1972, as amended coastal zone (16 U.S.C. 1451 et seq.) 3- E-ndangered and Endangered Species Act of No effect threatened species 1973, as amended (16-U.S.C. 1451 et seq.) 4. Fish and wildlife Fish and Wildlife Coordination No effects on .1. habitat Act (16 U.S.C. Sec. 661 et seq.) wildlife habitat 5. Flood plains Executive Order 11988, Flood No effect plain Management 6. Historic and National Historic Preservation One historic site cultural- properties Act of 1966, as amended (16 submitted for U.S.C. Sec. 470 et seq.) nomination to National Register. One archeological site covered by State Plan and ElS. 7. Prime!and unique CEQ Memorandum of August 1, Gain 377 acres prime farmland 1/ 1980: Analysis of Impacts and important farm- on Prime or Unique Agri- land cultural Lands in Implementing the National Environmental Policy Act 8. Water Quality, Clean Water Act of 1977 (33 Reduce suspended U.S.C. 1251 et seq.) solids and debris on Waimanalo Stream. 9. Wetlands Executive Order 11990, Pro- No effect tection of Wetlands Clean Water Act of 1977 (42 U.S.C. 1857h-7 et seq.) 10. Wild and scenic Wild and Scenic River Act, Not present in rivers as amended planning area (16 U.S.C. 1271 et seq.) 1/ This plan-EIS addresses Agricultural Lands of Importance to the State of Hawaii which include prime, unique and other important agricultural lands. 78 RELATIONSHIP TO OTHER PLANS AND POLICIES Installation of the recommended plan irrigation system will facilitate the implementation of the State's proposed Waimanalo Agricultural Park Plan (Ref. 1). The State plan aimed at irrigating approximately 1,800 acres, but it was based on preliminary estimates of how much irrigable land and water were available and the peak crop water requirements. Subsequent investigations, during the development of the Waimanalo Watershed Plan, resulted in a firm water supply of 2.4 million gallons per day and 60 million gallons storage which will fully irrigate approximately 1,252 acres. Some modification of the State's plan will be necessary, but it will accomplish the basic purpose of sustaining and enhancing diversified farming in Waimanalo Valley. Water Resources Regional Study The Hawaii Water Resources Regional Study presents 105 recommendations and specific actions for the balanced conservation, development, and use of Hawaii's water and related land resources (Ref. 14). From among these recommenda- tions, 38 were selected in the Regional Plan as deserving priority implementation. The Waimanalo Watershed recommended plan, together with the State's proposed Agricultural Park Plan, are responsive to seven priority recommendations as follows: 10-2 (in part) Recycle wastewater and exchange for high quality irriga- tion water (1975-2000). 11-1 (in part) Encourage agricultural operations to locate near existing sewage treatment plants where feasible (1975-2000). 14-1 Use more efficient irrigation methods--convert to drip or sprinkler irrigation where feasible and reduce storage and transmission losses (1975-2000). 14-2 Provide additional irrigation water--improve diversion, storage, and transmission systems; develop more surface water . . . and study the reuse of treated domestic wastewater for irrigating diversified crops . . . (1975-2000). 15-3 (in part) Apply land treatment practices to cropland and pastures . . . (1975-1990). 20-5 (in part) Maintain sanitary conditions in streams and drains by litter controls . . . and implement improved soil con- servation practices on croplands and.grazing lands (1975-2000). 21-4 (in part) Preserve and enhance wetlands . . . (1975-2000). Coastal Zone Management Plan The -Walmanalo Watershed Plan is consistent with Hawaii's Coastal Zone Management Program, policies, and guidelines. State Functional Plans - Hawaii State Plan Both the watershed plan and the proposed agricultural park plan are in agreement with the State functional plans for agriculture and for water resources development (Ref. 23 and 24). The 12 functional plans--still to be 79 approved by the State Legislature--are key elements of the Hawaii State Plan which is the comprehensive planning document for the entire state (Chapter 226, Hawaii Revised Statutes). The governor has directed State departments to use the functional plans as the basis for all planning (Ref. 30). The State Agriculture Plan has as one of its two fundamental objectives con- tinued growth and development of diversified agriculture throughout the State. In addition the plan emphasizes two specific objectives: achievement of productive agricultural use of lands most suitable and needed for agriculture; and achievement of efficient and equitable provision of adequate water for agricultural use. Key objectives from the State Water Resources Development Plan are: 1. Improve the quality, efficiency, service, and storage capa- bilities of system supplying agricultural water; 2. Increase the use of treated sewage effluent for irrigation purposes; 3. Promote agricultural water conservation; and 4. Provide adequate, reasonably priced water supplies for agricultural production. County General Plan The functional plans are part of a statewide planning system to execute and coordinate State and County planning. Waimanalo Watershed is in the Koolaupoko District of the City and County of Honolulu. The district is covered by the Development Plan Ordinance published in October 1980 which designates ten land use categories. All irrigated agricultural production proposed in the recommended plan is on land designated "agricultural." Both the watershed plan and the State's proposed agricultural park plan are responsive to the Statements of General Principles in the ordinance as follows: Waimanalo will remain a rural area having extensive acreage devoted to diversified agricultural pursuits and a small low-density residential community. To promote pleasing and attractive living environments, panoramic mauka and makai views and views of major landmarks should be pro- tected. 80 CONSULTATION AND PUBLIC PARTICIPATION GENERAL Agency consultation and public participation were an integral part in all phases of planning and environmental evaluation conducted by the Sponsors and SCS. All contacts were noted and the results reported and evaluated in the documentation. AGENCY CONSULTATION Agency consultation began with the March 9, 1978, notification by Windward Oahu Soil and Water Conservation District to the Governor that it was applying for federal assistance under Public Law 83-566. This initiated the Project Notification and Review System required by the Office of Management and Budget (Circular No. A-95). Several agencies then participated with the Sponsors and SCS on August 9, 1978, in a field examination of the area to identify water and related land resource problems and related environmental considerations. Based on the results of the field examination, SCS requested planning authoriza- tion from the SCS Chief in Washington, D.C. This authorization was granted January 19, 1979, and agencies and the public were notified. Intensive planning and environmental evaluation began in the summer of 1980 under the direction of the SCS. Federal, state and county agencies participated in the "scoping process" described in the section, Inventory and Forecastinq. The multidisciplinary planning staff and associated SCS specialists consulted with various federal, state, and county-agencies and group representatives on specific items as necessary, and periodically on an informational basis, and to provide appropriate opportunities for participation. The environmental evaluation required by the National Environmental Policy Act (NEPA) was conducted in conjunction with planning. A Notice of Intent to Prepare an Environmental Impact Statement was made to meet both Federal NEPA and State requirements. Similar consultation continued throughout the environmental evaluation. Often one meeting or contact served both planning and evaluation purposes. The U.S. Fish and Wildlife Service (USFWS) was consulted in accordance with Section 7 of the Endangered Species Act, as amended, concerning' threatened and endangered species that may be present in Waimanalo Watershed. USFWS also participated, together with State Division of Forestry and Wildlife, in an evaluation of the wildlife habitat. The State Historic Preservation Officer and the Heritage Conservation and Recreation Service were consulted concerning sites for possible nomination to the National Register of Historic Places and the likely effects of project actions on historical and archeological sites. The notice of availability of this draft plan-environmental impact statement for Waimanalo Watershed was publish(@d-in the Federal Register, the Hawaii Office of Environmental Quality Control Bulletins, and local newspapers. Notices were mailed to all Waimanalo residents and to interested agencies. The Plan-EIS was distributed for review and comment to the agencies and groups shown on the following list: 81 U.S. Government Advisory Council on Historic Preservation Department of the Air Force Department of Agriculture- Agricultural Stabilization and Conservation Service Animal & Plant Health Inspection Service Forest Service Office of Equal Opportunity Department of the Army - Corps of Engineers Department of Commerce Office of Coastal Zone Management Marine Fishery Service Department of Housing and Urban Development Department of Health and Human Services Department of the Inter*ior Fish and Wildlife Service Heritage-Conservation and Recreation Service Department of Transportation - Coast Guard Environmental Protection Agency Federal Power Commission State of Hawaii Department of Agriculture Department of Land and Natural Resources Coastal Zone Management Division of Forestry and Wildlife Division of Water and Land Development State Historic Preservation Officer Department of Planning and Economic Development Office of Environmental Quality Control University of Hawaii Institute of Marine Biology Water Resources Research Center College of Tropical Agriculture and Human Resources City and County of Honolulu Board of Water Supply_ Department of General Planning Department of Public Works Division of Wastewater Management Groups Ad Hoc Committee for Kawainui Congress of Hawaiian Peoples Environmental Defense Fund Friends of the Earth Lani-Kailua Outdoor Circle League of Women Voters of Hawaii National Audubon Society Hawaii Audubon Society National Wildlife Federation Natural Resources Defense Council, Inc. Sierra Club (National) Hawaii Chapter - Sierra Club Waimanalo Council of Community Organizations Waimanalo Farm Bureau Federation Waimanalo Neighborhood Board Waimanalo Planning Committee 82 PUBLIC PARTICIPATION A major consideration in the deve lopment of the plan and environmental impact statement was to provide interested and affected groups and individuals opportunity to participate. The Sponsors and SCS developed a public participa- tion program to achieve a high level of participation. Many individual contacts were made with farmers and other interested persons to gather data and, most importantly, to solicit participation in planning and environmental evaluation. Forms used to record information included Flood Damage, OMB No. 40-R3805 for flood damages and Irrigation Questionnaire, OMB No. 40-R3807 for irrigation. A mailing list was prepared and maintained to ensure timely notification of meetings and distribution of materials. A newsletter, Waimanalo Watershed Up-Date, was distributed to all Waimanalo postal patrons at important points in the planning process (October 1979, September 1980, January 1981, April 1981, and August 1981). The newsletter was also used to advise local residents of meetings and the availability of information for their review. Upcoming meetings and the availability of information were announced in newspaper notices and articles, media spots, posters, and at meetings of interested groups. Newspaper articles and media coverage also informed people of general progress during planning. Public meetings were held beginning early in the preauthorization phase of planning with the meeting held August 29, 1978, to discuss the Field Examination Report. A public workshop was held on election day, Saturday, September 20, 1980. Participation was enthusiastic and opinions were expressed on various charts listing problems, opportunities, possible measures for alleviating problems or realizing opportunities, and the effects of those measures. Another large public meeting held on Saturday, January 24, 1981, presented the identified problems and opportunities and the preliminary alternative plans that were under consideration. (NED, EQ, Primarily Nonstructural, and Without Project plans were included in the irrigation improvement proposals.) The meeting also covered both structural and nonstructural solutions to some of the flooding problems. An extensive discussion followed the presentation, and several suggestions were made by attendees for areas needing additional study. An edition of Waimanalo Watershed Up-Date and a letter from the Sponsors to each January 24, 1981, meeting attendee informed interested parties on modifica- tion and completion of the planning alternatives. Next a technical review coey of the plan-environmental impact statement was given informal local distribution. This preliminary version is circulated within SCS for technical review and, at the same time, copies are made available for interested groups, individuals, and local agencies (including local offices of federal agencies) for an informal review. After revision, the plan-environmental impact statement has now been published as a draft and officially distributed for formal, interagency review. Public partiZ-1pation in this review is encouraged. All comments from this review will be considered in preparing the final plan-environmental impact statement. Responses to all comments received on the draft, will be included in the final. 83 LIST OF PREPARERS PRESENT TITLE POSTGRAD. RECENT PLAN-EIS YEARS IN STUDY EXPERIENCE PPEPARER THIS POSITION DEGREES SUBJECTS YEARS USDA, SOIL CONSERVATION SERVICE Multistate Planning Staff, Portland, OR David E. Johnson Staff Leader 1 B.S. - Ag. Eng. Civil Eng. & Public RB/WS Staff Leader - 5 Prof. Eng. CA Admin. State Design Eng. 8 Lloyd D. Booker Soil Cons. B.S. - Ag. Econ. Environ. State Environ. Spec. - 4 00 State Res. Cons. 4 Hilton E. Griffing Ag. Econ. B.S. - Agronomy Ag. Econ. RBIWS Ag. Econ. 16 M.S. - Ag. Econ. Elwin A. Ross Planning Eng. I B.S. - Ag. Eng. Civil Eng. Area Eng. - 13 Prof. Eng. OR & ID Land Surveyor OR West Technical Service Center, Portland, OR Ttechnical assistance) Earl B. Alderman Civil Eng. Tech. 0 years Civil Eng.) Soila Mech. Tech. 5 David D. Thackeray Civil Eng. - I B.S. - Civil Eng. Civil Eng. (area Prof. Eng. OR office) - 5 Carolyn A. Adams Landscape Arch. - 2 B.S. - Landscape Arch. Landscape Arch. Landscape Arch. - 2 Prof. Landscape M.S. - Park Admin. Consultant - 5 Arch. David C. Moffitt Environ. Eng. - 5 B.S. - Civil Eng. Sanitary Eng, Environ. Eng. - 2 Prof. Eng. - CA JULY 1981 PRESENT TITLE POSTGRAD. RECENT PLAN-EIS YEARS IN STUDY EXPERIENCE PROFESSIONAL PREPARER THIS POSITION DEGREES SUBJECTS YEARS RECISTRAT10N USDA, SOIL CONSERVATION SERVICE SCi State Staff, Honolulu, HI Harry M. Means State Cons. Eng. - 4 B. S. - Ag. Oft. Civil Eng (coast. -3, Prof. Eng. - NI plan. - 9) Kenneth H. Kaneshiro RB/WS Staff Leader - 6 B.A. - Goo. Environ. Geo. (plan.) - 9 Prof. Geo. - ID Glenn G. Ahuna RB/WS Hydra. 4 B.S. - Civil Eng. Public Admin. Pro f. Eng. - KI & CA Gail H. Taukamoto RB/WS Econ. I B.S. - Ag. James C. L. Lum Civil Eng. I B.S. - Civil Eng. Ag. Eng. 2 Prof. Eng. HI CID Civil Eng. - 2 Ln John W. Bedish State,Res. Cons. - B.S. - F&W Mgt. Wetland Ecology Soil Cons. - 5 M.S. - F&W Mgt. Harry R. Sato State Soil Scient. I B.S. - Ag. Soil Scient. 8 Prof. Soil Scient. M.S. - Soil& Otis M. Gryde District Cons. - 11 B.S. - Ag. District Cons. - 10 Land Surveyor ND` Soil Cons. - 10 Has S. Coray Soil Cons. - 7 B.S. - Range Mgt. District Cons. - 26 Soil Cons. 2 Stanley J. Souia Soil Cons. Tech. - 16 A.A. Arts MAJOR CON'TRIBUTORS OUTSIDE SCS James Y. Y00himoto, Chief, Project Development Branch, Department of Lend and Natural Resources, Division of Water and Land Development, Honolulu, Hawaii Dr. W. J. Apt, Professor of Hematology, University of Hawaii, Honolulu, Hawaii Ralph S. Saito, Wildlife Biologist. Department of Land and Natural Resources, Division of Forestry and Wildlife, Honolulu, Hawaii William B. Len?an, Fishery Biologist, U.S. Fish and Wildlife Service, Honolulu. I'lawaii Earl Heller, Archeologist, Department of Land and Natural Resources, State Historic Preservation Officer, Honolulu, Hawaii JULY 1981 REFERENCES 1. State of Hawaii, Department of Land and Natural Resources, Division of Water and Land Development, Report R 61, Waimanalo Agricultural Park, April 1980, prepared by Park Engineering, Inc. 2. USDA, Soil Conservation Service, Soil Survey of Islands of Kauai, Oahu, Maui, Molokai and Lanai, State of Hawaii, August 1972; and the map, Agricultural. Lands of Importance to the State of Hawaii, 1977 3. Harland Bartholomew and Associates, A General Plan for Waimanalo Valley, January 1959 4. ':Environmental Research Consultants, Socioeconomic Structure of Waimanalo, September 28, 1979 (submitted tF @Environmental Communications, -Inc.) 5. Waimanalo Neighborhood Board, Results of April 1980 Waimanalo Neighborhood Board Survey on Resident Opinions and PrioriTir-e-s-Physical and LiTn-dUse Issues, June 1980 6. McAllister, J. Gilbert, Archeology of Oahu, 1933, Bishop Museum Bulletin No. 104 7. Sterling, E. and C. C. Summers, Sites of Oahu, 1978, Bishop Museum 8. "State of Hawaii, Department of Agriculture, Recommendations for a Waimanalo Agricultural Park, November 1977 9,@ USDA, Soil Conservation Service, Waimanalo Watershed Field Examination Report, November 1978 10. @Exchange of correspondence between SCS and Hawaii Institute of Marine Biology, February 1981 11. AhUimanu Productions-, AnOrnithological Survey of Hawaiian Wetlands, December 1977, prepared for U..S. Army Engineer District, HonTlulu 12. Exchange of correspondence between SCS and U.S. Fish and Wildlife Service 13. Federal Insurance Administration, Flood Insurance Study City and County of Honolulu, March 1980 14. Hawaii Water Resources Regional Study, Hawaii Water Resources Plan, January 1979 15. City and County of Honolulu, Department of General Planning, Development Plan Ordinance, Koolaupoko, October 1980 16. State of Hawaii, Department of Planning and Economic Development, Population Projections (and Ref. 14) 86 17. State of Hawaii, The Hawaii Register of Historic Places., May 1980 18. Exchange of correspondence between SCS and the State Historical Preservation Officer and with the Keeper of the National Register 19. State of Hawaii, Department of Land and Natural Resources, Division of Water and Land Development, Flood Management Plans and Preliminary Engineering Studies for the Waimanalo Flood Control Project, October 1976, prepared by Fukunaga and Associates, Inc. 20. Lee, K.H., A Survey of Maunawili Ditch and Other Water Supply Development in Maunawili Valley, December 5, 196U- 21. Exchange of correspondence between SCS and Dr. W. J. Apt, Professor of Nematology, University of Hawaii 22. Exchange of correspondence between SCS and the Director of Public Works,- City and County of Hawaii. 23. State of Hawaii, Department of Agriculture, State Agriculture Plan, October 1980 24. State of Hawaii, Department of Land and Natural Resources, State Water Resources Development Plan, September 1980 25. State of Hawaii, Department of Land and Natural Resources, State Conserva- tion Lands Plan, September 1980 26. State of Hawaii, Depa rtment of Land and Natural Resources, State Historic Preservation Plan, September 1980. 27. State of Hawaii, Department of Agriculture; and USDA, ESCS, Statistics of Hawaiian Agriculture, 1979, June 1980 28. Food Quality Labs, Waimanalo Irrigation System Water Quality Investigation, June 1981, conducted for Soil Conservation Service, Hawaii 29. Stream Channel Modification in Hawaii. Part A: Statewide Inventou of 7 .Streams; Habitat Factors and Associated Biota, Apri 1978, Biological Services Program, U.S. Fish and Wildlife Service 87 INDEX Abstract i Inspection 58 Agreement Installation ii,iii,iv,54 (See Watershed Agreement Introduction 5 and O&M Agreement) Inventory 7,8,9,10,16,18,19 Agricultural Park Plan Irrigation 3,9,11,12,13,21,22,23, (See Waimanalo Agricultural 47,72,76,79,80 Park Plan) Ag Park Subdivision 28,54,56,73 Kailua Reservoir 9,10,11,12,43, Alternatives 1,20,24 74,75 Appendices 90 Kawainui Marsh 4,9 Archeological sites 2,8,19,4@,51, 52,56,70,73,78,81 Land ownership 1,8 Authority i,ii,5,55- Land treatment iv,21,22,48,59,67,68 Land use 1,3,7,18,42,43,71,72,73,74, Bellows AFS 7,9 75,76,79,80 Benefits i, 3 Landrights i,ii,3,48,53,54,55,56,59, 60,61,71 Candidate plans 2,41,42,43,46 Lined Ditch Plan 1,21,36,41 Climate 7 Combine with BWS 21,37,38,41 Maintenance-irrigation system iv,9, Consultation 81 12,13,21,57,67,68,71,74,75 Contents vi Maps 25,27,29,31,33,35,37,39,90 Contracting 55 Maunawili Watershed ii,3,4,7,9,12,16, Costs i,iii,3,42,43,53,59,60,61 21,47,54,56,59,60,61,67,68,76 Cultural Resources 2,8,43,52, Mitigation 10,11,50 56,70,73,78,81 National Economic Development Economic Conditions 8,11,44,45, Plan (NED) 2,21,23,26,42,43,44,46 71,79,80 Nematodes 1,9,12,21,22,45,47,48,57, Effects of recommended plan 3,32, 72,76 42,43,44,46,72 Nonstructural Plan 1,2,21,22,30,42, Endangered species 2,10,18,50, 43,44,46 52,78 Energy requirements 43,71 Objectives 20,23,79,80 Environmental Impact Statement i,5, Operation iv,9,12,21,57,67,68,74,75 16,52,72,81,83 O&M Agreement iv,57 Environmental Quality Plan (EQ) 2, 20,23,28,42,43,44,46 Permits and compliance ii,51,52,54, Evaluation of alternatives 24 55,56,79,80 Photographs 90 Financing ii,iii,iv,54 Plan elements 1,47 Fish 10,16,52,70,74,78 Preparers 84 Flood plains 2,18,22,52,78 Prime and important farmlands 2,3,7, Flooding, storms 1,2,11,14,21, 14,18,21,23,28,32,42,46,71,72,75, 22,76 76,78,80 Forecasting 16,18,19 Problem and opportunity Formulation 20,21 identification 2,11,12,13,14,15, 21,22,23,46,75,76,77 Hazard from structural failure 11, Project interaction 44,79,80 43,45,48,50,75 Project setting 1,2,7 Historic site 2,8,15,19,21,24,28, Public meetings 16,20,46,81,83 43,46,51,52,56,73,74,77,78,81 History 5,8 88 Reader's guide 5 Recommended Plan 1,3,32,42,43,44,46, 47,72 Recreation 1,7,10,11 References 86 Relationship to other plans 5,44,46, 47,79,80 -Replacement iv,58,67,68 Reservoir safety 11,43,45,48,71,75 Risk and uncertainty 45 Scoping 16,20,81 Social conditions 8,71,75 Solid waste collection iii,10,,15, 19,21,23,28532,42,48,51,53,54, 56,57,59,60561,67,69,70,71,73, 74,75,77579 Soils 7 Sponsors ii,1,5,54,55,56 Structural data 1,26,28,30,32, 34536538,40547,48,90 Summary 1 Tables, List of (See Contents) Technical assistance 3,21,22,26,28, 30,32534536,38,40548,53,59 Treated sewage effluent 1,4,10,13, 18,19521,22526,28,32544,475515535 59,60,61562563566,73,76,79,80 Visual Resources 10,15,18,23,42, 69,73574 Waimanalo Agricultural Park Plan 2,3,4,5,16,26,28, 30,32,34,36,38,40541,46547,79 Waimanalo Irrigation System (WIS) 2,9,11,12,13516, 19,21,47572,76,77 Waimanalo Stream 9,11,18,43,70, 72,74578 Waimanalo Valley, description 7 Water quality - ground water 9, 18572,77 - Water quality - irrigation 9,11, 12,13519,21,45,46,47,725735 76,80 Water quality - streams 9,18,43, 52,70572574,78 Water rights iii,4,12,16,21,47, 53554,56560,76 Watershed Agreement ii Wetland 1.7,10,16,18,78 Wildlife 10,70,74,78,81 Without project 16,18,19,34,45 89 APPENDICES APPENDIX A EIS LETTERS AND RESPONSES Wat be inctuded in the 6inat copy APPENDIX B PROJECT PHOTOS APPENDIX C MAP - AREA SUBJECT TO FLOODING IN THE EVENT OF STRUCTURAL FAILURE APPENDIX D ENGINEERING DRAWINGS Plate 1 - Plan and Profile - Regulating and Storage Reservoir Plate 2 - Details - Regulating and Storage Reservoir Plate 3 - Structure Details Plate 4 - Details - Treated Sewage Effluent Use Plate 5 - Solid Waste Collection Sites APPENDIX E PROJECT MAP AND OTHER MAPS Figure 1 -Project Map Figure 2 -Agricultural Lands Important to the State of Hawaii Figure 3 - Land Use and Flood Plain 90 K iLu, xk it kr 'Z@ lee -FORC -4f At 07 Moak- SCALE I"= 4000 Feet PHOTO NO. 1 - Antae photo o(I Waunanato Watnshc)d aud adjace;it ct,@eas- PHOTO NO. 2 The Waimanato LkAigation Sy@stem ditch betow the tunnet outtet on Aniani Nui Ridge. .,jjbjw,&.I A !I NI: PHOTO NO. 3 Waimaywdo Vafeey 4Aom Aniani Nui Ridge. C.U44z (pati) o@) the Kootau, Mountain Range aAe in the backgAound. 'AP PHOTO NO. 4 Kattua RezeAvo,(A wtth Antant Nut Rtdge tn the backg.kound. f -A@ Aw Mob . . ...... %awe Mar PHOTO NO. 5 Smoft @aAms on Wa4manato VaUey Atoo4. "000, Waimanato IAAigation PHOTO NO. 6 sy,5tem @tume and tAeztte in the iAAi- gated aAea. A 2A 4n; _V; PHOTO NO. 7 Waimanato IAAigation System Atume and tAestte at a typicat Aoothitt stteam c@tozsing in the iAAigated aAea. United States soil P.O. Box 50004 Department of Conservation Honolulu, HI Agriculture Service 96850 August 19, 1981 In accordance with Section 5 of the Watershed Protection and Flood Prevention Act (Public Law 83-566), as amended, Section 2 of Executive Order 10913, and our responsibility as assigned by the Secretary of Agriculture, we are transmitting, for your review and comment, the draft watershed plan-environmental impact statement (EIS) for the Waimanalo Watershed, Hawaii. The final plan will require approval by the appropriate committees of the Senate and House of Representatives, before federal assistance is authorized. The EIS was prepared in accordance with Section 102(2)(C) of the National Environmental Policy Act of 1969 (Public Law 91-190). We are requesting that comments on this document be received by this office on or before October 17, 1981. If your comments are not received by the due date, we will assume you do not wish to comment. Sincerely, ZJACK P. KANALZ State Conservationist Enclosure The Soil Conservation Service SCS-AS-1 is an agency of the 10-79 Department of Agriculture 07" 4 PHOTO NO. 8 Waimanato MAigation System di,5tAibution ditch. 4i 4.1 19 PHOTO NO. 9 IAAigated ttuck cAop@s in the @oAegAound and banana,s in the backgAound. W, 0, PHOTO NO. 10 NmseAy cAops in the tAAigated aAea gAming undeA @shade. PHOTO NO. 11 Landscape nm@seAyr cAop being pAe- paAed 6oA tAans- ptanting. p AJOP L A 40,1 PHOTO NO. 12 Typicat banana pad Ishowing di@@eAent geneAatio" 57, ,74@k f PHOTO NO. 13 TYpicat dAainageway on the vattey A@oot. Ip ly PHOTO NO. 14 GaAbage and oAchaAd debAis dumped along Aoad- ,side btocking dAainageway. Romana Peak in the backgAound. 442@ A, PHOTO NO. 15 Site o@j the ptanned Uttigation Ae,5eAvoiA with Otomana Peak in the backgAound. r""W A; M 40 4W &A *J Ad 1 0 -I 4P A, W-4 V iw 44 4 A0. I 4r AL. 6L t .7 NIR 4 1 4 J.4 % X 4A., % of Ilk It; Aw I 2 Pr z, orage ServoIr va, IV A `AIR, 41f r NW W, 4- -7 dIL AN WPRW" Residences and Areas Subject to Flooding The area subject to flooding by a possible struct+ failure was analyzed In the Event of Structural Failure AREA SUBJECT TO FLOODING IN THE through each channel adjacent to and downstream of the proposed storage W th, t Proj ct Recommended Plan r u ilua Reservoir Proposed Reservoir EVENT OF STRUCTURAL FAILURE Item @!@St Ina reservoir Four channel areas (A, 8 C and D) were analyzed assuming I Residences with Water that the possibility exists that a sudden structural failure could occur Above the First Floor - 21 77 and produce a flood flow in either channel but probably not in all channels WAIMANALO WATERSHED Area Flooded NA ISLAND OF OAHU, HAWAII simultaneously The flooded areas below the convergence of two or more Residential Zone 0 ac 17 9 ac 41 tA, LN@' k1K 3AW 'lip 7 - i1i. @@. channels is the larger area of any one initial flow JULY 1981 Commercial Zone 0 ac 0 9 ac Agriculture Zone 31 6 ac 212 4 c Channel K represents the channel area subject to flooding by a possible 0 V4 3/8 _V2 MILE Parks 3 5 ac 54 1 ac Structural failure of the existing Kailua Reservoir CALE 19600 U S DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA MRTtAND OR 1981 0400 Ongated Emergency 20*80 spillway Overhead P,,tub/e, Pole j Electric wer Line Screening 0 margency Structure spoway Exit Channel Ndturl,-@ Stream t con -an-1 , i Hole No. 1 7*72 320- Crest of Emergency a ungateo, Spillway - Ele@. 308Z Test Hole No,2 310- 18 F- LU LL, LL 300- 0 z Spillway Exit 2 Channel _j Lu 12,160 T Hole No.5 9*90 V, 280- 16*57 cente"Ine 14+50 610 120 270 ? Test Hole No.4 Test Hole No F00 2+'00 4 '00 r.+'00 8+60 Scale in Feet PROFILE OF UNGATED EMERGENCY SPILLWAY 41111-Test Hole Sites 290- o'l No, 2 I M N. 5 070 Slarilret Drain Outlet 1280- o, House to Natural Stream Channel Z60 270- 260- 0250- k LEGEND 240- Silt (MH, ML) ith Boulders Memotode Monitoring Structure Boulders PLAN OF RESERVOIR a EMBANKMENT LOG OF TEST HOLES Gravel, Silt (GM) 340- Water Level (9/10/80) ungoled Emergency 320- ill Crest Elev. 308Z CENTERLINE PROFILE OF EMBANKMENT U) Top of Dom Eleie 3//z t uj Z 300- z 0 280- 260 0+00 1+00 2+00 3+'00 4+'00 5@w 64!00 7+'00 8+00 9+00 10+00 11+00 12+00 15+00 16+00 17+'00 18+00 19+00 20@W 21+'00 22+00 APPENDIX D: PLATE I PLAN & PROFILE WAIMANALO RESERVOIR SITE 4 WAIMANALO WATERSHED CITYAND COUNTY OF HONOLULU, HI JULY 1981 USIDA-SICS44=71AND, ON. 1961 SPILLWAY DISCHARGE IN CFS 0 40 80 120 160 200 240 280 320 1 1 1 1 1 1 SURFACE AREAS (ACRES) 1 2 3 4 5 6 7 8 0 340- Tr.,elMg Fine Mesh Sclee. Structure 340- 320- V No4-1 WS. Ele,.308Z 320- Spilloy D,.chaige 300- MAHAILUA ST I one 2 1.75 1/ Existing Ground Surface) 'Copacted I _j Etev. jO6'z z 16"Cqnduit xc. Material) Zon 7/ _j from Anioni Nui 300- Ridge Tunnel Outlet 280- 1.75 LU LU W I storage LL Capacity 11 Z 280- Z 260- 16 Conduit from 0 Screening Structure < to Bottom, of > Surface < LLI > Reservoir Bottom of Reservoir _j Area Ld Elev. 2459 LL _j Li Final Grade Excavoled 8 Rock Fill Surface 260- 240- with Sand - Gravel Mix before placing RIC Lining 240 1 1 1 1 t 220 0 10 20 30 40 50 60 70 0-00 1+100 2+00 3+00 CAPACITY (MILLIONS OF GALLONS) AREA -CAPACITY CURVES SECTION THROUGH INLET WORKS, DISCHARGE CURVE 320@ Normal Pool W S. Ele. 3061 Efev 3/1Z 300- _j L - 75 Zono@ 2 u) E'isfing Ground Su'face__@ /I (Compacted Excavated Material) R. 5 .75 1 Zone Z material brought to this L'i slope beleen sto. 4*00tog@00 LUJ280- and 15*00 to 20teo Zone 3 Zone 3 z RIC (Rock) (Rock) 0 Lining 1.75 Zone 4 (Exsting Mferiall @Ii260- bi _j Uj 24" RIC Encased Condud-@ ad Bottom of Reservoir Elez 2452 240- Final Grade Excavate Gated 1@@rod.. Dainage Outlet C14"Irrigation Delivery Su,fdo ith Send- Gravel Mix before Structure Drainage ksfem Collection of 0 fo Channel "'afn Line d 8 Rock FY-11 Inlet RIC Laining Placement edge of ock rill (Live Stream) 220 1 1 1 1 1 1 1 1 1 t 0@00 1+00 2 00 3+00 4+00 5.00 SECTION THROUGH OUTLET WORKS TYPICAL SECTION APPENDIX D: PLATE Z DETAILS REGULACTING a STORAGE RESERVOIR WAIMANALO WATERSRED CITY a COUNTY OF HONOLULU, HI JULY 19a@ on. panne fmm Sewage /Von - return 7rewment Plant Flow Chfc# Valve ) PmjW Pii0elifte to hold,fig Pands ro Reservoir II/ow, C"a hm 4 "Flow MWVr (150 psi rof&W F/aw central P-P Valve 'Zill ra LISW PLAN VO/V* Valve 8ppo" to allo (WIS Operated; tuser Operated/ return flow PLAN PLAN power unit $prqv Deflector C-1-1k EIW.132 Q Deb"s ro Holding Pfton Siam, C01/8 Nozzles Air 4"FlowMater (150 s! rolool) Flow control Main Line valve 77-M 7roveffing Screen SUMP PUMP STRUCTURE (Woven Mesh Belt) 7b User AT SEWAGE TREATMENT-..i 77- valve conc. r PLANT (W/S oper 8/Oc*$ lluser operated) 0 1 4 SCALE IN FEET runnel Vurlor P, SECTION 'an,, a', ese'voir SECTION IRRIGATION OUTLET DETAIL- TYPICAL STRUCTURE AT INLET TO RESeRVOIR SCALE IN FEET 0 1 2 3 L i 15 SrALEIN FEET L i mimst-9 SECTION Arr"70tion out/st SECTION ro) ,pc.,, PIPE INLET STRUCTURE AT TUNNEL OUTLET 0 1 SCALEINFEET Manhole I Air Support vent RocIr E D--) TZ Main Oster U.0 mp APPENDIX D: PLATE 3 Valve cmk. Tunnel (NIS operated)- I Rad STRUCTURE DETAILS WAIMANALO WATERSHED CITY a COUNTY OF HONOLULU, HI flow JULY 1981 p1peline to PLAN Tmsb Reservoir Roc*t ROO BOOSTER PUMP-TYPICAL @.@-dn 1, Ha@lli , @Ibnls p (W11 pp,,.Idj @Cl_loc.,. @Iolv. t.., operated) @r.pnn,1011,11 A Os"' C-4 SCALE IN FEET J USDA-8MMPTLAND. 00. 1911 ling Mlxlng amber F SECTION VIEW GATED DIVISION BOX AT INLET A prim- C/ r 12"dio. slide gate for erafion 8 GENERAL PLAN EX451117g A Top ofEmbankment Outlet to each Cell WAIMANALO SEWAGE Settling Tank PLANT Existing S, Ele. 961 System X's 0 -'-stilling well for float SCALE IN FEET + Akmal W@ Rev. 941 V 941 controlled contact for $.,ICA at se-age plant + IWO fivir Pond -dio. L10.1 _A_ Elev. 912 Covered Sludge Beds z - - 7. *'F.- + . L.:1 '_ :.' . :r . . . . Pipeline "o'@ Sewage Pia' 0 SCALE IN FEET Conduit to + Control Bldg. 0of" EMERGENCY OVERFLOW DETAIL Elev 962 Ele.95 Normal WS V f62@949 3 Standard Pip. Drop Co 1=@ed 'failic" Ele. .409 Conduit Outlet in Diversion Channel Box @1. Bottom of Ponds Eta 87. SCALE IN FEET E t. Wel xis. 9-A A Area " 11 / + Exist. I BOX19" A GENERAL PLAN Exist. wel TREATEO SEWAGE EFFLUENT PONDS L% P,;@oefi to 7reated Emergency Sewoge Effluent Ponds Diversion Overflow Channel 0 2r, Z9, / -Grade to )'@Wosed Stan or 96 1" Outlet P,pe rop PUMP SUMP PROPOSED SYSTEM EXISTING SY5rFM -16 " C. '9CP flow ron, Mixing Chamber in Elev Sewage Rant ce// 2 Ele. :@-Iniiel 3.00 hwert 300 Capacity - 5ffig cell / DETAIL OF AREA "A" Capacity - Z 5fflg kA, line to 9 It ofH. SCALE IN FEET LF-looling pump @j Gated Division Box APPENDIX D: PLATE 4 D Grade to DETAILS Outlet lnwrf6.00 TREATED SEWAGE EFFLUENT USE '4 0 Lo@' 4 Invert 300 'WA, ZP.A@41HA r ly )S Apeline from xl E851119" /Q 101, 1CP Sewage Plant WAIMANALO WATERSHED .X a Elev A@Pelme to Wong a We// 9_29 bwe,13.00 Foremost dairy areas CITY a COUNTY OF HONOLULU, HI 20 0 20 40 '1110rE;4ssvmwd Elevations - SCALEINFEET JULY 1981 L=A4CS4WTI.AND, OR. 1981 Cyclone r ype Fence Paved Area Dampsters For Vehicle Traffic Cyclone rype Fence ) 0 Dumpsters Paved Area ) it For Vehicle F1 7raffic Plantings Plentl.ngs lz@ 0 0,0 @zz@ Oje PL AN PLAN 1(106 Ahiki Street Site Hihimanu Street Site Wailruponaba St. Paved Area For Vehicle TrO f f ic Appendix D Plate 5 Dumpster5 Solid Waste Collection Sites WAIMANALO WATERSHED City and County of Honolulu Cyclone July 1981 PG V For r ro'f e f d Ve c Ar Ole 'bo aMpster's D 01 r .YPO PLAN Fence W @aikupanaha Street Site Wolmona 4woferslyed 72 ISLAND OF OAHU Z- C) BELLO S AIR F INa,monoto Rage A, LOCATION MAP SADDLE CITY STMIN OAHU-*qJ6 (IN CT ox\ Gog,n HU 5 010 Sto a 10 > '30 LL @30 ----34 AN N Ul U' AA N "EL-- % 44 ESV19 (-4,@ 411 // al TS v MAUNAWILI fr 11% titer To nX Ali* ..00-0 00 *Water @INA W/ Tank 4:1 Owat r T.n.kl-' Water ank 0 FOREST v RESERVE Source Dom mop pnspared by SCS, WTSC Corto Unit from USGS 1 24,000 quads Thematic detail compiled by Portland Multistate Planning Staff U S DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA KS AORT@ND OR 19M 1 .W 0" oimdn Wotershed 72 t ISLAND OF OAHU NA % BELLO S Al R C LOCATION MAP SADDLE CITY TATION OAHU--g& 4,0,.4 (INACT S 1,10 S 8 M X 30 A III AN L- unnel 5, G. 47 TAI LEE NA K-- vrr. R )IR zll/ LQ univ, of W14 13 a r A at Water Tank ank 0 FOREST RESER \___ @Woimd 0010 W .2te"Sh_ Sourci: Base map prepared by SCS,WTSC Carta Unit from USGS 1:24,000 quads. Thematic detail compiled by Portland Multistate Plannin 9 Staff from Agricultural Lands of Importance to the State of Hawaii dated 1/77 adjusted to Development Plan Map for Koolaupoko, City and County of Honolulu dated.10/80. U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA SCS PORTLAND OR. 1981 WeoiMannia S4.0ftlershed 72 ISLAND OF OAHU U S AIR F wamnona: LOCATION MAP R,dge fN CITY STATION OAHU--q26 ONACT BM AfMANALU ou ,@; jjp.AU. runnel Gap TAI-4 W' KP- .., .1j 41 o- Un It- M4 W/L I VOIR Tank if A14WI Tank Water Tank 440 FOREST A RESE Source: Base map prepared by SCS, WTSC Carlo Unit from USGS 1:24,000 quads. Thematic detail compiled by Portland Multistate Planning Staff. Agriculture, Residential, and Park zones from October 1980 City and County of Honolulu Development Plan Mop. 100 Year Flood boundary from FIA Floodway Map, Honolulu, HI, September 3, 1980. U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA SCS PORTLAND. OR 1991 I NOAA COASTAL SERVICES CTR LIBRARY I i( 3- 6668--141-11097 5 1