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CENTER coastal Zone, information Center U.S. ARMY CORPS OF NORTH CENTRAL DIVISION GENERAL INFORMATION GREAT LAKES SHORELINE DAMAGE CAUSES AND PROTECTIVE MEASURES TC 330 .U5 G7 1972 May 1972 ACKNOWLEDGMENTS The Division Engineer of the North Central Division, Corps of Engineers wishes to acknowledge the assistance of the Chicago District offices in the preparation of this pamphlet. Further, the comments provided by Detroit and St. Paul District offices, the Coastal Engineering Research Center and Lake-.Survey Center, NOAA, Department.of Commerce are. greatly appreciated. First Printing - September 1969 Revised - December 1969 Revised - October 1971 Revised - May 1972 FOREWORD The problem of adequate control of erosion on the shores of the Great Lakes has seriously concerned engineers and.riparian owners since the early 1800's. The existence of the present above-average levels on the Great Lakes emphasizes the effects of the fluctuating lake levels upon shore properties and other uses of these waters. This pamphlet has been prepared to provide interested parties infor- mation which will be useful in the consideration 0- of remedial measures for problems resulting -Proi- r@roslon 3r(3/e)- 4.n,.jrd8.t-*C- of tlie Primarily, it is a. compilation of data and vn Q@ facts related to Great Lakes water levels and to shore erosion and inundation problems along the Great Tlakes shores. 7, T-1_'n-771-@@n- Property of CSC Library This report is organized in three parts. Part I is a his- tory and Ibackground discussion of lake levels, causes of fluctuations ------ --- and, most important, effects of lake level changes on shorelines. Part II discusses the role of Federal and State Governments in various activities and responsibilities on the Great Lakes related to -water and shore areas. It includes information on available data and the sources of such data. Part III is a. brief discussion of several emergency- type remedial measures, estimates of their cost and genera.1 statements on their appli- S DEPARTMENT OF COMMERCE NOA.A cability to various typical situations. This COA',,') AL SERVICES CENTER section is not.intended to be used for design of permanent protective works -without Ithe '@@34 SOUTH HOBSON AVENUE advice and guidance of qualified engineering ChARLESTON SC 29405-.2413 coi-isultants. PART I all interests concerned. All regulation plans LAKE LEVELS are approvedby the Governments of the United States and Canada. Changes in Great Lakeslevels have long Several years ago the Great Lakes were in been of concern in the affairs of those a period of low levels. In fact, Lakes living along the lakes or dependent upon lake Michigan and Huron levels were at an all-time transportation. Records of lake levels have record low level, starting in February 1964 been kept by the U.S. Lake Survey, Corps of Engineers since 1860. This agency is now an and ending in January 1965. This was the office of the Department of Commerce, NOAA. result of unusually low precipitation during the period 1962-1964, which amounted to about Levels of the Great Lakes fluctuate from 11.5 inches less than normal for the Lake year to year and also from month to month Michigan basin and 7.2 inches less than normal during each year depending upon the volume of' for the Lake Huron 'basin. During this period, water in the lakes. In addition, there are property owners on Lakes Michigan and Huron daily and even hourly fluctuations of levels and to a lesser extent on the other lakes, resulting from unbalance or tilting of the became accustomed to these lower levels. Since lake surfaces caused by -winds and barometric this period of low levels,above-average amounts pressure differences. The source of Great Of precipitation have occurred in the Great Lakes water is the rain and snow which fall Lakes basin. Lakes Michigan and Huron have on the lakes themselves and on the land areas risen again, returning to their average which drain to them. level in early 1969. The other lakes are above Seasonal fluctuations, caused 'by the annual their long-term average levels. The bulletin weather pattern, are superimposed upon the of lake levels attached as inclosure 1 provides long-term variations resulting from extended the recorded levels for the previous year and periods of 'below or above normal precipitation. current year to date for each of the lakes, Unusual variations in the amount of.water including Lake St. Clair. General information evaporated from the lakes can also significantly on Great Lakes levels is shown in the following alter the net amount remaining in the lakes and table 1. thus the lake levels. Because of the size of the Great Lakes and the limited discharge capacities of their outflow rivers, extreme high or low levels and flows persist for considerable time after the factors. which caused them have changed. Where the outflows from the lakes are artificially controlled by regulatory works, as is the case with Lakes Superior and Ontario, the releases of -water are made in accordance with the plan for the regulation of the lake's levels and outflows which maintains the lake within a range of water levels acceptable to TABLE 1 GENERAL GREAT LAKES INFORMATION LAKE LAKE 'LAKE LAKE LAKE LAKE DESCRIPTION SUPERIOR MICHIGAN HURON- ST. CLAIR ERIE ONTARIO Outlet river or channel St. Marys Str. of St. Clair ..Detroit Niagara St. Lawrence. River Mackinac River River River River Length in iniles 70 - 27 32 37 502. Average flow in CFS (1860-1971) 75,100 .52,000 188,000 189,000 202,000 239,000 3 Monthly Elevations in feet IGLD(1955) 2 Average (1860-1971) 600.39 578.69 578.69 573.06 570.39 244.77 Max imum 602.o6 581-94 581.54 575-70 572-76- 248.-o6 Minimum 598.23 575.35 575-35 569.86 567.49 241.45 Average - winter low to summer high 1.1 1.1 1.1 .1.6 1.5 1.8 Maxinum - winter lowto surmer high 1.9 .2.2 2..2 3.3 2.7 .3-5 Minimum - winter low to suriuner high o.4 0.1 0.1 0.9, 0.5 0.7 Annual precipitation in inches (1900-1971) Average on basin (land & water) 30 31 31 34 34 Average on lake surface 30 30 31 33 33 1. The Straits of Mackinac between Lakes Michigan and Huron are so wide and deep that the difference in the monthly mean levels of these two lakes is not measureable. 2. Lake St. Clair elevations are available only for the period 1898 to date. 3. Lake elevat@ions are as recorded at Marquette (I. Superior), Harbor Beach. (L. Michigan-Huron), Grosse Pointe Shores (L. St. Clair), Cleveland (L. Erie) and Oswego (L. Ontario). Recorded elevations are affected by man-made changes such as: regulation of. outflows. from Lake Superior (1921) and Lake Ontario (1960);. diver- sions of water from Hudson Bay basin into Lake Superior (1939) and- from Lake Michigan basin into Mississippi basin at Chicago (before 1860); and regimen changes in the' natural outlet channels from the lakes throughput the period -@f record. 3 TEMPORARY RISES IN LAKE LEVELS Winds, particularly of storm velocity., and sharp gradients in barometric pressures over short distances have pronounced effects on lake levels and can cause a wide range of fluctuations. These short period fluctuations are superimposed on the prevailing levels and M may cause unusually high levels during periods of above average levels. &MCM High storm levels at one end of, a. lake are accompanied by lower levels at the opposite end. Pronounced fluctuations.from these causes are experienced also in bays and other shallow portions of each lake such as in Green 38Y oh. Lake Michigan, and in Saginaw Bay on Lake Huron and both ends of Lake Erie. In.terms of monthly average values, water. levels in,the various shore.line,:localities are substantially the same as for all other areas around the shores of each.of the Lakes. Howevel@., 1/7 the water level at a particular locality or ILI' any other shore.'a.rea on a lake may be, and frequently is,.temporarily higher or lower than. the-monthly average value, due to the effects of storms over the lake. The height of the temporary rises above the monthly average level varies for the different shoreareas depending on a.number of factors. For a severe' storm@ the temporary.rise at a particular locality nay be in the order of two or three @feet above the monthly average lake level for the larger, deeper lakes such as Lake Superior. For shallow Lake Erie@ temporary changes of greater extremes of feet or more have been experienced. Table 2 shows short period fluctuations in,lake levels at selected gage .......... sites. Storms over the lake causing.such temporary rises also generate high waves which beat against and erode the materials forming the shoreline, particularly where the shore is com- posed of,sand, clay or other erodable materials. TABLE 2 SHORT-PERIOD FLUCTUATIONS IN LAKE LEVELS AT SELECTED GAGE SITES Rise for Lake and Period MAXIMUM RECORDED One-Year Gage Location of Gage Rise Recurrence Record In Feet Interval In Feet SUPERIOR at Marquette 1903 -iQ70 2.8 1.3 MICHIGAN at Calumet Harbor 1903-1970- 3.5 1.8 (Chicago) HURON at Harbor Beach 1902-1970 2.5 0.9 ERIE at Buffalo 1900-1970, 8.2 4.9 .ERIE at Toledo 1940-10,70 5.3 3.1 ONTARIO at Oswego 1933-1970 2.2 0.9 NOTE: Short period fluctuations are the differences between the monthly mean elevation and the maximum reading of the.ga.ge during.each month. The 11recurrence interval" is the average time interval within which an event of a given or greater magnitude will take place. 5 All CAUSES OF EROSION s which In the continuing natural processe act on Great Lakes shorelines, erosion can and C does occur at @ll stages of lake levels. Dur- dL ingperiods of high lake levels, however, the rate of erosion is accelerated, and the extent greatly expandedl The TnbLjor causes of erosion of the shore- line are as follows: (1) wave action, @2) underground water seepage, (3) frost and de action and (4) surface water runoff. Wave action works directly on the beach or at the toe of the bank eroding away materi- als chiefly of clay, silt, sand and gravel. .During periods when lake levels are above their average leveis@ erosion by wave action is accelerated, because the beaches are narrower or @ubmerged and the waves are able to attack the unprotected toe of the banks or bluffs directly@L The best natural protection that the upland shore could have from wave attack is wide beaches'6 1. Where underground water seeps out of exposed bluffs of unstable material, it causes slumping and further weakening of the material, often resulting in large slides. Seepage often takes place through sandy layers in glbt6lal till bluffs. Problems with under.@ --.Z- ground water may sometimes be caused by man.&made ai@ainage works. One of the most severe contributing factors to shore erosion is frost and ice AI it action. In certain of the fine-grained silty types of soils along the lakes., the alternate freezing and thawing can cause soil weakening to the point where soil slides take place. Frost and ice formation in fissures in clays, glacial tills or shale bluffs may also con- tribute to their erosion. Shore ice is another source of damage, when broken up and driven onto the beaches b,,,, on-shore storms. Lake bottom material may 'Lie scoured out and damage to structures often occurs. However, shore ice also provides beneficial protection of the shore from erosion by winter storms. Surface water runoff carries with it,large, amounts @Df erodable material, particularly where barren, steep sloped bluffs are present. Where surface water is carried off by man-made drainage works, inadequate protection of the sewer outfall'may result in increased erosion at that point. 'PART II directives from the U.S. Congress. The directives are in the form of either a re'solu'd EXISTING FEDERAL LAWS ON BEACH EROSION CONTROL tion of the Public Works Committee of the AND LAKE INUNDATION jq Sena.te..or the House or a separate item in a pub 1 i C' worKs authorization bill. The Soil The Federal Goverwnent's role in. shore Conservation Service, Department of Agriculture e,rosion control is defined in the provisions of has broad authority to undertake studies for Public Law 826, 84th Congress, approved July 28, upland watershed protection. These reports 1956, as amended by the River and Harbor Act deal primarily -with means of reducing flood of 1962 (PL 87-874), approved October 23, 1962 flows into the Great Lakes. and is farther anmended by the River and Harbor The provisions of Section 111,of the River Act of 1965 (PL 89-298), approved October 27, and Harbor Act of 1968 authorizes the Corps 1965. Under this statute the Corps of Engineers of Engineers to investigate, study and construct participates in the Isolution of shore erosion projects for the prevention or mitigation of problems by making studies of such problems shore damages attributable to Federal navigation entirely at Federal expense for shores eligible works.. Investigation of the feasibility or under existing law for Federal participation in desirability of work under this authority must the cost of remedial action. The present be formally requested by a State, County or policy for Federal participation in the cost other properly constituted local authority, of works-for shore protection applies, generally, Flooding or inundation damages onthe to publicly owned shores. Privately owned Great Lakes shores are a direct consequence of shores may be eligible for Federal assistance building or placing improvements on the lake4s only if there are significant public benefits flood plain. A possible solution to the arising from public use or from protection of problem on a long-term basis would involve nearby public property, and provided further studies.to determine pertinent flood hazdrdtj that any protective works are economically including the stability of the shoreline.ahd justified. definition of the rate of erosion which:@an be Privately owned shores qualify for Federal expected. This information could 'be fu@nished assistance only if public benefits along such by the Corps of Engineers under its flood , shores will be considered to include those tlain information program. This program was resulting from: (a) Public recreational use, authorized by Section 206 of the 1960 Flood opportunity for which will be assured for the Control Act (Public Law 86-645 approved- economic life of the project (50 years) or 1_4 July 196'j) and was greatly expanded by (b) Prevention of damage to near shore publicly amendment to this act in l@)66 and HD 4654 89th owned facilities such as highways, buildings, Congress, 2nd Session entitled "Unified parks, etc. The protection of privately owned National Program for Managing F_!ood Lossesii, property that does not result in such public The Corps has a Flood Plain Management Services benefit,,-- @jill not qualify for Federal aid. Program operating in North Central Division and The Corps of Engineers also conducts beach each of its District offices. This program erosion control surveys or reviews and updates makes available to Federal, State and local previous reports -in the 'basis of individual- governmental agencies information, guidance 8 and advice on the flood hazard i,7hich will permit A major disaster is defined as any "flood, them to proceed with such planning, engineering drought, fire, hurricane, earthquake, storm-or studies, construction and other action as may other catastrophe which, in the determination be necessary for wise use of flood plains. of the President, is or threatens to be of Requests for studies to determine flood hazards sufficient severity and magnitude to warrant should be initiated by responsible local and disaster assistance by the Federal Government state authorities concerned with the problem. to supplement the efforts and availab-ie resources of state and local governments in alleviating E@@GENCY FLOOD AND COASTAL STORM ACTIVITIES the damage, hardship, or suffering caused thereby". Functions reserved to the President include The authority for Federal assistance in the determination of a "major disaster decla- emergency flood and coastal storm activities is ration, the affected areas are then defined bY the set forth,in Public Law 09/84 (33 United States Director, Office of Emergency Preparedness. Code,701n) as amended by Section 206 of the The Corps of Engineers may be called upon Flood Control Act a.pproved,October 23, 1962; and to render assistance when specifically a-,_--thorized in Section 9 of the Flood Control Act approved by OEP as follows: June 15, 1936 (33 U.S.C. T02 g-1). Preceding (1) Damage surveys and investigations. and.during flood and coastal emergencies, the (2) Performing assigaments on pub-@ic and primary missions of the Corps of Engineers are private'lands protections and other work preparation for and conduct of operations under essential for the preservation of life and statutory authorities assigned to the Chief of property. Engineers. Essentially the following respon- (3) Clearing debris and wreckage. sibilities are authorized: (4) Emergency repair or temporary replace- (1) Preserve Federally owned and maintained ment of public facilities. flood control works and other facilities (5) Provision of technical advice and operated by the Corps of Engineers. engineering services. (2) F@arnish appropriate technical assistance Unless a major disaster has been declared, to state and 'Local authorities upon request, the only aid that can be provided to private advising them in their efforts to maintain the land owners or public landowning agencies by integrity of flood control works and Federally the Corps of Engineers is Technical Assistance. authorized shore and hurricane protection The Corps of Engineers can provide technical projects under their jurisdiction. assistance to local interests through consul- (3) if responsible state or local author- tations to acquaint them with erosion and .Ities are unable to cope with the flood or inundation processes and potential on the dbasta.l storms situation, direct Federal Great Lakes, by making existing reports and assistance may be provided either by supply of other.useful data available, and by making needed materials or equipment or by undertaking appropriate recommendations for suitable types Federal flood fighting or emergency protection. of protection. The Federal Disaster Act of 1950 (Public taw 875/81) authorizes Federal assistance to state and local governments in a major disaster. 9 CORPS OF ENGINEERS Lake Michigan from Bridgman, Michigan including NAME AND ADRESS 0F DISTRICT OFFICES Indiana, Illinois and Wisconsin Shoreline to DESCRIPTION OF SHORELINE COVERED Peninsula Point, Michigan BUFFALO DISTRICT ST. PAUL DISTRICT District Engineer District Engineer U.S. Army Engineer District, Buffalo U.S. Army Engineer District, St. Paul 1776 Niagara Street 1210 U.S. Post Office and Customhouse Buffalo, New York 1207 St. Paul, Minnesota 55101 Lake Erie shoreline, Marblehead, Ohio to Lake Superior from the Minnesota-Canadian Border, Buffalo, New York, including Pennsylvania. including the Wisconsin shoreline to Au Train shoreline, Niagara. River shoreline Point, Michigan All of the Lake Ontario shoreline, St. Lawrence NAME AND ADDRESS OF DIVISION OFFICE NORTH CENTRAL DIVISION River shoreline to the Canadian Border Division Engineer U.S. Army Engineer Division, North Centrla 536 South Clark Street DETROIT DISTRICT Chicago, Illinois 60605 District Engineer U.S. Army Engineer District, Detroit OTHER FEDERAL AGENCIES P.O. Box 1027 LAKE SURVEY CENTER Detroit, Michigan 48231 Director Lake Survey Center, NOAA Lake Michigan from near Bridgman to Mackinaw U.S. Department of Commerce City, Michigan, and from St. Ignace to the 630 Federal Building and U.S. Courthouse Peninsula Point, Michigan Detroit, Michigan 48226 Lake Superior shoreline from Au Train Point to Levels of all the Great Lakes are recorded and Sault Ste. Marie, Michigan, and including published by the Lake Survey Center. A hydro- graph showing the levels of the various lakes the St. Marys River shore during the period of record 1860 to date is available from this office. The Water Level All of the lake Huron shoreline, St. Clair Bulletin similar to inclosure 1 is published monthly and copies are available to interested River shoreline, Lake St. Clair shoreline, individuals upon request. Detroit River shoreline. Lake Erie shoreline t Marblehead, Ohio CHICAGO DISTRICT District Engineer U.S. Army Engineer District, Chicago 219,South Dearborn Street Chicago, Illinois 60604 AVAILABLE CORPS OF ENGINEERS DATA AND REPORTS Ashtabula,O@-Penn. State Line 350/82/2 Sheffield Lake Com. Pk.,, Ohio 414/87/2 The Corps of Engineers has completed a Presque Isle Penn., Erie, Pa. number of erosion-control studies and several and 397/86/2 flood control studies for various reaches of the Great Lakes,shores., In general, the DETROIT DISTRICT reports on these studies discuss the erosion CORPS OF ENGINEPP or flooding problems of a given shore segment, recormend desirable plans of protection, and 4aXe,Erie provide the supporting technical information Midhigan-Ohio State Line to 63/87/1 and data,on which the recommended,plans were Marblehead, Ohio developed. Copies of the reports on,these *Reno Beach, Lucas. County, Ohio 554/8o/2 studies along the localities listed below are *WAter Levels of the Great Laket-L 424/83/2 availablefor inspection by the public at the Local Flood Protection Project, Corps of Engineers' District Office under Point Place, Lakewood-Luna Fier -which the report is listed. Copies of the and Detroit,Beach, Michigan reports may also be'available in local public libraries located in the general vicinit of Lq4e, Michigan y the study are,a6 Bbttien County, Michigan 3W85/2 Report Identification House Document CHICAGO DISTRICT No./Coftgress/Session' .CORPS OF ENGINE;ql@p BUFFALO DISTRICT L4p Michigan CORPS OF ENGINEERS,, Illinois Shore 28/,83/1 Lake Ontario City of Evanston, Illinois 1W89/1 Niagara County, N;Y. 271/78/1 City of Kenosha., Wisconsin 273/84/2 Selkirk Shores State Park N.Y. 343/83/2 Racine County,, Wis.consin 88/83/1 Fair Haven State Park, N.Y. 134/84/1 Milwaukee County, Wisconsin 526/79/2 Hamlin Beach State P.ark, N.Y. 138/84/1 Two Rivers to Manitowo-,- Wis. 348/84/2 Fort Niazara State Park,.TT-..Y. 31 a s/ q i Lake Erie Sandusky Bay, Ohio 126/83/1 Denotes Flood-Control (inundation) Report Sandusky 0. - Vermilion, Ohio 32/83/1 Vicinity of Huron, Ohio 220/79/1 Vermilion, Ot-Sheffield Lake Vil. 229/83/1 Sheffield Lake Vil., O.-Rocky Riv. 127/53/1 Cleveland and Lakewood,:Ohio 502/81/2 Euclid, O.-Chagrin R., Ohio 324/8@/2 Chagrin R., O.-Fairport, Ohio 596/81/2 Fairport, O-Ashtabu.1a, Ohio .351/82/2 NATIONAL SHORELINE STUDY OTHER REPORTS In 1968, the 90th Congress authorized the SHORE PROTECTION PROGRAM - Department of Corps of Engineers to accomplish a National the Army, Office, Chief of Engineers: Appraisal of shore erosion and shore protection Revised June 1971. This report provides needs. This National Shoreline Study and the information on assistance by the Corps of existing Federal shore protection programs Engineers in shore protection. Copies are recognize beach and shore erosion as problems available from the North Central Division for all levels of government and all citizens. office or the office, Chief of Engineers, To satisfy the purposes of the authorizing Washington, D.C. legislation, a number of related reports were published in August 1971. All are available to concerned individuals. GREAT LAKES REGION, INVENTORY REPORTS. (Report covering one of the 9 major drainage areas of the United States) assess the nature and extent of erosion; develop conceptual plans for needed shore protection; develop general order-of-magnitude estimates of cost for the selected shore protection; and identify shore owners. A report entitled "SHORE PROTECTION GUIDELINES" describes typical erosion control measures and present examples of shore protection facilities, and present criteria for plan- ning shore protection programs. A report entitled "SHORE MANAGEMENT GUIDELINES" provides information to assist decision makers to develop and implement shore management programs. A report entitled "REPORT ON THE NATIONAL SHORELINE STUDY," addressed to the Congress, summarizes the findings of the study and recommends priorities among serious problem areas for action to stop erosion. 12 PERMIT REQUI=E1,JTTS n@@ota Dept. of Co n8ervation Div. of Water, Soils & Minerals Federal and state permits are required Centennial Building prior to the construction of any work in, St. Paul, Minnesota 55101 under, across, or on the banks of navigable waters of the United States. In general, both Nel,l York: Central Permit Agent Federal and state permits are required prior New York State Department to the initiation of construction of shore -,f 7nvironmental "onservation, protection structures along the shores of,the 50 Wolf Road Great Lakes lakeward of the highwater mark. 1.1hanv, Kew.York 12201 Federal permits are issued by the Corps of Engineers, usually only after a. state permit Ohio: Staff Coordinator has been obtained. A pamphlet entitled Ohio Dept. of Natural Resources "Permits for Work in Navigable Waters", Ohio Dept. Building, Room 815 describing the procedures for app@ying for a 65 South Front Street Federal permit, may be obtained free of charge Columbus, Ohio 43215 from any Corps of Engineers district office. Information regarding the procedures for Pennsylvania: Chief Engineer applying for a state permit should be obtained Pennsylvania Department of from the following state-agencies. Environmental Pesources P. 0. Box 1467 Illinois: Chief Engineer Harrisburg;, Pennsylvania 17120 State of Illinois Division of Waterways Wisconsin: Director, Bureau of Water and 201 West Monroe Street Shoreland Management Springfield, Illinois 62706 Division of Environmental Protection Wisconsin Dept. of Natural Resources Indiana: Chief, Division of Water Box 450 Indiana Dept. of Natural Resources Madison,, Wisconsin 53702 605 State Office Building Indianapolis, Indiana 406325 Michigan: Michigan Water Resources Commission Department of Natural- Resources Stevens T. Mason Building Station A Lansing, Michigan 48926 -'Ave,, PART III SHORE PROTECTION METHODS Protective measures are generally built for the purpose of preventing recurrence of damages to shore property, including'measures to prevent damage from erosion and wave action, and measures to prevent damage from inundation. Shore protection methods may be divided into three basic types, (1) those that provide pro- tection by means of a higher beach, (2) those that shield vulnerable portions of the shores from the forces of waves and (3) those that reduce or prevent flooding of lower adjacent lands behind such protective structures. In plan ni ng sho re prote ctive me a. sures, it should be borne in mind that the high levels -which occur at one time on a lake will probably recur in the future. Also, -when lake levels are above their long-term average the possibility exists that such levels may continue during the fall and spring seasons. The greatest shore 14P property damages are more likely to occur in the fall and spring seasons when the most severe storms occur on the Great Lakes. When permanent protection is being planned for'a locality, consideration must be given to the range of high and low levels which have occurred in that region over the period of record. W 14 ADVANTAGES, DISADVANTAGES AND LIMITATIONS areas as well as a potential recreation area; OF SHORE PROTECTION STRUCTURES (2) their effect may spread over considerable- lengths of shore; and (3) at those locations Each of the different types of shore where groins would be effective, protection protective structures has its own inherent can generally be provided at lower initial advantages, disadvantages and limitations. cost by their use. Disadvantages in the use These attributes generally dictate the method of groins include: (1) they are not as and degree of protection to be employed and positive.as a sea-wall for continuous upland in some instances provide an indicator as to protection; (2) they may be outflanked; what not to do, as well as what should be done. (3) they are ineffective in areas of low Bulkheads, seawalls and revetments differ littoral drift unless granular beach fill is only in their primary function. By definition, artificially added and (4) the area immediately a bulkhead is a structure separating land and downdrift of the groin may be subject to water areas, primarily designed to resist increased scour. earth pressures. Also, by definition, a Offshore break-waters provide protection seawall is a structure separating land and to upland property by reducing the -wave energy water areas, primarily designed to prevent impinging on the shoreline. Submerged break- damage to an upland area while retaining its waters are a type of offshore breakwater and seawall limit in a fixed position. A seawall have the same general effect depending on may also be designed to resist earth pressure. depth of submergence. These may also be used A revetment is a facing, generally of stone, to reduce beach slopes artificially,.and thus built to protect an otherwise stable embank- prevent loss of material. The principal ment against erosion from wave action. The advantages are that: (1) they provide pro- principal advantages attributable to bulkheads, tection without impairing the usefulness of sIeawalls and revetments are: (1) they provide the beach; and (2) they may provide sheltered positive protection and generally permit mor@@-- waters for boating. Disadvantages are that: intensive use of the adjacent upland; (2) they (1) the relatively high cost of construction; maintain the upland area on a fixed alignmont; (2) they protect only the shor@e behind them and (3) they are adaptable to providing pro- and for a short distance updrift; and (3) tection to an area with a minimum of incidental they may_cause downdrift erosion. damage to adjacent areas. Disadvantages of A beach fill protects the upland 'by inter- bulkheads, seawalls and revetments are: posing a width of 'beach 'between the upland and (1) they are not effective in maintaining a the lake to a:bsorb wave energy. The advantages beach; (2) they provide no protection to of protection 'by 'beach fills are its pleasing adjacent areas which will continue to erode appearance.and possible recreational value. and eventually expose the flanks of the The principal disadvantages are that they protected property. require an adequate supply of 'beach material Groins provide upland protection by inter- economically located and continuous maintenance cepting part of the granular material that,is must 'be provided. moved along shore by wave generated currents. There are a number of publications which Their principal advantages are: (1) the have 'heen prepared 'by various Federal and resulting beach provides protection to upland 15 State Agencies providing technical information This pamphlet provides only brief descrip- on shore protection measures.. The most complete tions on the methods of shore protection. and comprehensive publication is Technical Reference to the above mentioned literature as Report No. 4 entitled "Shore Protection Planning well as the retaining of a qualified Engineerincc-, and Design". This is a compilation of avail- able knowledge on coastal engineering which Consultant experienced in coastal engineering has been prepared by the Coastal Engineering work is highly recommended. It should be pointed out, as indicated in another section Research Center, Corps of Engineers. The of this pamphlet, that each State along with latest edition may be purchased at a cost of C the Federal Government requires-issuance of a $3.00 from the Superintendent of Documents, permit prior to construction of shore rrotections U. S. Government Printing Office, Washington, on the banks of navigable waters. The Corrs of D. C. 2o4O2. Engineers issues the Federal pery-it. Other sources of technical assistance are as follows: 1. SHORE EROSION IN OHIO, State of Ohio, Department of Natural Resources, Division of Shore Erosion, February, 1959. 2. LOW COST SHORE PROTECTION FOR THE GREAT LAKES, Research Publication No. 3, University of Michigan Lake Hydraulics Laboratory in cooperation with Michigan Water Resources'Commission, reprinted October, 1959. 3. SHORELAND AND FLOOD PLAIN ZONING ALONG WISCONSIN SHORE OF LAKE MICHIGAN, A. R. Striegl, State of Wisconsin, Department of Natural Resources, Division of Resource Development. 4. GREAT LAKES SHORE EROSION IN MICHIGAN- STATUS REPORT, State of Michigan, Department of Natural Resources, Water Resources Commission, June lQ6Q. 5. SHORELINE EROSIOW STUDY, Lake Erie Lake County, Ohio, State of Ohio, Department of Natural Resources, August 1,069. 6. FLOOD PLAIN INFORMATIOB, Ontonagon River, Ontonagon, Michigan and Lake Su- -Derior Shoreline, Ontonagon County, I'lichigan, Department of the Army, St. Paul District, Corps of Engineers, September 1970. criteria for ADEQUATE HEIGHT OF PROTECTIVE STFJCTUREL prov4d4ng plans of pro-@@ecricn for a pa---ticular location might be obtained In addj_tion to short period fluctuations from one of "he completed Corps of Engineers' in lake levels that might occur in a locality erosion or flood control studies for the (ta:ble 2) the upper elevation limit of wave general lake locality listed on page 11 or action must 'be known in order to properly one of the technical references listed on .design necessary protective structures. page ir. One of the 'Principal natural conditions that-determine how high -wave action will reach on the shorelines (,wave runup) is the beach area condition 'between the upper limit of wave action and the existing still water lake level and the near-shore under-water zone between the water's edge and the lakeward zone where 'he waves *break. The slopes of the 'beach areas and near-shore under-water areas vary -widely through- out the Great Lakes shores. With a wide variation of bottom and beach slopes a change in the lake-level of one or two feet might make a difference of only a dozen feet or perhaps 100 feet or more in distance from the shore at -which waves 'break and also a change in the height of -wave runup may result. The vertical height to which water from a breaking -wave -will runup on a given pro- -tective structure determine the top elevation to which the structure,must be 'built to prevent wave overtopping and resultant flooding on -'-'Ile landward side, and to prevent possible damage b:,;- erosion. The proper elevation for the most economical groin system is re- quired.in order to provide the height and width of protective 'beach necessary for the locality. This runup, also called uprush, depends upon many factors such as the c9mposition of the structure, its shape, its slope, its rou Ighness, the depth of the water, the wind velocity and duration, etc. There is not an exact formula to determine the value of the runup, however, studies based on detailed information can lead to a very close approxima- tion. It is,noted that suggested design 17 PLANS OF EMERGENCY PROTECTION RECENTLY DEVELOPED MATERIALS FOR SHORE PROTECTION There are various methods for providing emergency protection rapidly at low- cost There are several medium cost protective which have been utilized on Great Lakes shores. methods that have merit which are classified as These methods in clude: (1) placement of a. intermediate protective measures both in cost granular fill. As an example the least amount and durability. of fill material that would provide a degree of In recent years severall new commercial protection will vary depending on the slope of products have become available which appear to the beach involved; (2) a temporary seawall have merit in providing medium priced shore at the base of the bluffs constructed of sand protection. It should be noted unless otherwise -bags filled with 'sand and cement; and (3) com- stated that no degree of performance or length bination of brush or timbers with sand bags. of life is known by the Corps of Engineers. However, these plans may result in only partial The providing of information on these or perhaps short-term protection for the commercial products is in no way intended to shoreline. imply that the North Central Division, Corps Generally speaking emergency protection of Engineers or any of its District offices may provide a reasonable degree of protection indorses the use of these specific commercial through the first storm with the degree of products as Great Lakes shoreline protective protection diminishing as additional storms measures. This information is provided to occur. Maintenance usually is necessary after advise property owners of the availability of each storm. It is estimated that the annual these products for use as shore protection. cost of maintenance of emergency protection The North Central Division office intends to could well be twice the initial construction provide similar information on other products costs. -which merit the same type application when It is difficult to make accurate comparisons such other items become known. The known sources of the effectiveness of the different methods of these products may be obtained from the -which have been utilized in various sites on North Central Division office or its District the Great Lakes shores since in no two instal- offices. lations -will there be exact similarity of such factors as shore topography, beach compositions, wave conditions, etc. The emergency protections briefly mentioned above are considered "low-cost" 'measures and are not types that will withstand the severe conditions -which occur on the shorelines of the Great Lakes. GABIONS Gabions are.steel wire mesh boxes or baskets (hexagonal triple twist mesh openings 3 "x4 made of a completend continuous metal fabric. that can be filled with pieces of ballast such as stone, boulders,,, bricks or broken concrete to produce a heavy wave resistant protective unit. Gabions are plable in units about 3' deep with several heights and lengths avail" able. The capacities vary from 1-5 cubic yards with the unit costs for the basket ranging $10.00 to 29.00 plus shipping cost., Gabions may be used in various type s of revetmen ts to protect slopes or provide a retaining wall. Figure 1 is a sketch showing 6 5'x61xl-L1 gabion 2 unit asseynbled-and figure 2 shows an example of a typical shore protective of this product,. The permanence of this-protection depends upon the life of the wire baskets as well as the proper One of the main features a design and preparation of its foundation which is the thin gabion apron (12 should include a filter. projects out beyond the super twice the depth of the antici The apron with its flexibilit to the changing contours of t SUPERSTRUCTURE protect the stiticture against For estimating purposes th ment as shown in figure 2 wou APRON BEFORE M00 pet foot of shoreline frontag labor involved would be addit material included in this est costing per ton deliver approximately 1/4 tons re ciu cubic yard capacity of gabion The use of gabions appears factory "do-it"Yourself" cons Gabi often have been used for sh measurest numerous localiti the Great lakes. APRON AFTER SETTLEMENT FIGURE 2 X FILTER MATERIAL It should be noted that one common defi- ciency of most "do-it-yourslef" revetments is that there is a complete lack of a filter matieral between the heavy cover material and the fine, easily erodible bluff or beach material. A commerical product of a woven sheet of polypropylene yarns can be obtained and used beneath blocks, rubble or gabions to prevent the sand from working out through the blocks or rubble this weakening the revetment or wall and causing settling. The woven material permits water from wave action or seepage to pass through it slowly but prevents the fine particles from being washed away. Costs of a suitable filter material in amounts between FIGURE 4 300 square feet and 10,000 square feet, including anchor pins, is something in the order of $0.12 to $0.15 per square foot. Assuming that a standard 18-foot wide strip might be used as a filter under material to protect the toe and slope of a bluff, it would cost from $2.16 to $2.70 per linear foot of frontage for this item. In many cases, existing stone or blocks could be reinstalled on the filter material to provide a much more effective protection requiring less future maintenance. Figure 4 is a sketch showing the use of the filter material in a typical stone rubble revet- ment on a sloped shoreline. The need for a filter layer beneath the rubble is a definite necessity as the voids between the pieces of rubble are large and the constant wave action will draw the sand or backfill foundation out through the rubble and cause it to settle and FIGURE 5 eventually collapse. Figure 5 is a sketch of a rubble mount groin showing similar use of the filter material. PRECAST CONCRETE SHAPES A number of precast concrete shapes intended for use either as shore r6vetment or in lieu of heavy coverstone are available. Generally these are patented products controlled loy a single supplier who collects a royalty for the use of his patent. Some have been tested in a limited number of prototype installations; others have been tested only, in scale models. One of these shapes is illustrated in Figure-6. The installed cost of such a single interlocking line varies t6tween $50 to $60 per linear foot for a basic 2-ton unit. Properly designed structures iising similar products would.provide long lasting protection but the costs are relatively high. Precast concrete shapes %r6uld be competitive in cost where suitable sizes and quality of stone are not readily available. Actual installations have been in eoastal areas but at least one supplier plans to have an installation on the Great Lakes t4 in late 19T1- RETE S TWO TON MULOCIKINO CONCI MISCELLANEOUS INFORMATION Property owners who are in danger of sustaining extensive damages should consult their local of,fice of the Internal Revenue Service for information relative@to "disaster losses" which might be claimed as deductions on Federal Income Tax. filing. It is believed that definite proof of such losses must be documented for each storm occurrence. Con- cerned owners should contact the Internal Revenue Service office for exact information or determination on individual situations. SOME CONCLUSIONS Under present laws and authorities the Corps of Engineers cannot aid shore property owners threatened by losses in construction of protective measures. It is the burden of the property owners to provide adequate protection for their threatened properties.otbe2-- wise danages will result. As has taken rln:!rj at many localities,, it is a very wise procedure for neighboring property owners to -work together in a cooperative effort to provide -well planned and properly placed measui-es of protection at the locality threatened. It is most important that exper-u advice be obtained from competent Engineering Consultants in the proper planning and determination of the specific design of shore protection. Property owners are advised to consult their local or state agencies responsible for shoreline pro- tective programs. It is believed that these agencies will have direct knowledge of qualified Engineer Consulting and Contracting Firms know- ledgable and experienced in providing shore pro- tective measures in their locality. 22 mr a, @ : #11,.. .0 M.- sk (r ..IIII.. 0 lk..., r@ 'i w : ., Z@ --3 2--- N, 0 --l i a I lumill MIND 6668 00002 3426