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0 W.P. COASTAL ZONE 10673 INFORMATION CENTER Coastal Zone Iformation JUN 14 1977 Center SHORE EROSION STUDY TECHNICAL REPORT APPENDIX 3 SHORELINE EROSION AND BLUFF STABILITY ALONG LAKE MICHIGAN AND LAKE-SUPERIOR SHORELINES OF WISCONSIN MILWAUKEE COUNTY D. M. Mickelson R. Klauk L. Acomb T. Edil B. Haas FEBRUARY 1977 GB 459.5 .M5 appendix 3 WISCONSIN COASTAL MANAGEMENT Wisconsin Coastal Zone Managment Program. This report fias been prepared through the cooperative efforts of the Wisconsin Geological and Natural History Survey, the University of Wisconsin (Madison, Milwaukee, Parkside and Extension), the Wisconsin Department of Natural Resources and the Office of State Planning and Energy. Assistance was further provided by Owen-Aytes and Associates. This report is being reproduced quickly and in a limited quantity for dissemination to local governments and interested parties. The report will be broadly available when reproduced in the fall of 1977 as an information circular from the Wisconsin Geological and Natural History Survey. Financial assistance for this study has been provided by the Coastal Zone Management Act of 1972 administered by the federal Office of Coastal Zone Management, National -Oceanic and Atmospheric Administration. COASTAL ZONE INFORINSATION CENTM SHORE EROSION STUDY TECHNICAL REPORT Appendix 3 Milwaukee County Wisconsin LA D. M. Mickelson, R. Klauk, L. Acomb (Geology) T. Edil, B. Haas (Geotechnical Study) Lq t US Department Of Commerce NOAA Coastal Services Center Library 2234 South Hobson Avenue Charleston, SC 29405-2413 2- INTRODUCTION This Appendix provides detailed information on shoreline conditions within much of the county. The order of materials in the Appendix is from south to north. Parts of the shoreline are. broken down by reach (see County Map) and geographic section within each reach. There is a text which describes the characteristics of shorel ine conditions at the beginning of each reach section. This.is accompanied by a map of the whole reach which shows the sections, public perception of erosion ha- zards, shore damage in 1952, short- and long-term recession rates, bluff height, shore protection structures, houses per mile, and boat ramps. Location of geotechnical borings is indicated on the county map at the beginning of the Appendix. Logs for'geotechnical holes and detailed location maps are given at the end of all of the maps in the reach con- taining that geotechnical site. For each geographic section (one mile long) a map showing the location of shore protection structures which are numbered and described in reports on file with the Department of Natural Resources. Also on the map, locations of measured profiles are shown along.the shoreline. A running description of bluff characteris- tics, materials making up the toe of the slope, and beach characteristics is also given. Engineering data such as safety factor the confidence level on this safety factor, and the distance the slope must retreat to attain a stable slope angle is also given. It should be noted that this distance assumes no wave cutting at the base of the bluff. This dis- tance is referred to in the text as a stable slope distance. Also in- cluded with each section is a set of profiles from the water's edge to the bluff top...-These profiles show stratigri@hy,-'slope angles, circles of failure, and calculated safety factors along the shoreline. The dis- 3 tance to a 5 foot depth of water is also given. The date.when the profile was measured is also given. Remember that the bluff profile could have changed since the-profiles were measured. The.meaning of abbreviations used in the Appendix is given on this page. For more detailed description.of the methods used in compiling the data, regional interpretations, and conclusions about the engineering characteristics and types of slope failure taking place refer to the main report (Shoreline Erosion and.Bluff Stability Along Lake Michigan and Lake Superior Shorelines of.Wisconsin) available from the State Planning Office and the Wisconsin Geological Natural History Survey. Symbols Used (itsed as nouns and adjectives) b boulders. C clay or clayey co coarse f fine 9 gravel m medium p pebbles s sand si. silt t till y cobbles tUA) till name SF Factor of Safety A - unsatisfactory 1.00) B - questionable (1.00-1.25) C - satisfactory ( 1.25) CL Confidence Level A - high confidence - at borehole B - medium confidence - neat borehole, stratigraphy visible C - low confidence - away from borehole, stratigraphy questionable SL Stability line - the distance slope must retreat to attain a stable slope angle. This assumes no erosion at toe and unchanged conditions of nature of material and water table. 4 Requon Is 57 141 'River REACH 11 Hill MO EER Bayside 74 1.8 N WWI 0 Deer ''Fax Point -An T-" qIen d.ale Whitefish Bay REACH 10 -T 41 NO co U mr CARTOL Ut Shorewood .1 .1 &T- 145 - - - - - - - - - - - - - - - - - - - - - - - 45 57 AVE T-741 6* A 13 3 3LUF LUI 94 "Milwaukee REACH 9 MEN L 13 Mo.-A., 0.7 r W 411 L@4 ilw Alli' 24 - - - - - - - - - - - - St. Framcis 36 4 V LAV M AVE Gr en a 45 :.Cudahy REACH 8 ield Hales e een dale ors. VE 24 6T- K outh. 1W Mi aukee - ---------- ranklin ti T REACH 7 Rim too R06 36 ... Oak Czeek 0 ---- - ------------- V REACH 6 38 32 Tc" d Ray TVA" d COW*" R-22-E NI[LIVAUK Co. DEPARMThe"4T CIO TR ATIC" VIV"mmo-op NNW..- SCA&E L_Q@Iftm 5 Reach 7 Location Reach 7 is located in southern Milwaukee County. It consists of approximately 4 miles of shoreline in sections 25, 24, 13, and 12, T5N., R.22E. and section 31, T.5N., R.23E. The southern boundary of the reach is at the Oak Creek Power Plant and the northern boundary is at the large groin in Grant Park. Land use in the southern of the reach consists of farming and parkland, whereas in the northern the land is used for resi- dential and industrial.purposes. Reason for Criticality This reach ranks 3rd on the Erosion Problem Area priority list with a value per mile of 26. This high ranking is based on 1) the Army Corps of Engineers 1952 Shore Damage Surveying, 2) the very high short term recession rate of 6 ft. per year, and 3) the Army Corps of Engineers critical area list. Reach 7A Reach 7 is divided into two parts based on the type and severity of bluff erosion. Reach 7A is an area.of relatively stable bluff directly north of the Oak Creek Power Plant. It is 2 mile long and located entirely in section 36, T5N. Section 31, T.5N. The part of section 31 that is included in reach 7 is directly north of the Oak Creek Power Plant. In this area the groin like action of the power plants protective structures have built a very wide sand beach. The sand beach dissipates the wave energy and protects the toe of the bluff so that stable slopes are maintained. The bluff height in this stretch is about 80 ft. and the topographic profile of the bluff shows one long straight slope inclined at approximately 0 0 20 to 25 The bluff is entirely vegetated with large trees. 6 The stratigraphy of the section consists of a gray clayey till near the foot of bluff overlain by a series of lacustrine silts and sands. Reach 7B. The northern division of reach 7 is an area of highly unstable bluffs with.rapid recession rates. The failure type is rotational sl umping in most places with little or no vegetation on the bluff and narrow beaches not protecting the-toe.. Section 25, T.5N. Beginning at Oakwood Road and moving northward (Bluff Cond. map, sec. 25) about 1/3 of a mile consists of a scalloped bluff top with fairly large slump blocks and steep scars. These are discrete slumps, concave in plain view. The failures are seated in or at the base of the silt and interbedded fine sand just above the lower till unit. Profile 1 (sec. 25) shows a typical bluff profile acros s one of the slumps and profile 2 (sec. 25) shows a profile typical of areas between the slumps. Profile 3 is across an older slump block adjacent to a stream gully. The toe material is primarily slumped clayey, silty till. Exposures are reasonably good in areas between slumps although there is a skin layer of debris on the slope. Major seeps occur at the top of the lower till. The middle 1/3 of section 25 (Bluff condition map) has few large discrete slumps but shows nearly continuous rotational failure in small blocks (oblique R22-9). This may be bec ause more stratified material, including the silt-clay units are acting as indiv.idual failure surfaces. Exposures in this section are poor. Major seeps in this section occur at the.top of the upper till and minor seeps are present at several levels within the clay and interbedded sand units above. Water can be seen in most of the depressions between slump blocks. The beach in this area is less than 5 feet wide causing the slumped material at the toe to be eroded. No structures are present in section 25. 7 In the northern part of section 25 and southern part of section 24 the bluff has mainly straight slopes and failure is by slide and fall. The stratigraphy of section 25 consists of a lower gray clayey till (with a few shale pebbles) which ranges in thickness from 6,ft. to 18 ft. A few inclusions of lacustrine material are present in the till. This till is overlain by a sequence of lacustrine deposits consisting primarily of silt interbedded with fine sand. The silts are overlain by till in all loca- tions except profile 3 in section 25. Here a wedge of medium sand and silt interbedded with fine sand and is 60' thick. This wedge is local and was probably deposited in front of the advancing ice front which deposited the upper till. The upper till, identical (in the field) to the lower till in the sequence ranges from 10 feet thick in the northern part of section 25 to 68 feet thick at the southern edge of section 25. The thick till is located in the inter- section of the bluff with a moraine and coincides with the highest part of the bluff in this section. Section 24, T.5N. Section 24 is in the cent.er of reach 7. Land use of the bluff top is primarily for industrial purposes. The conditions present in the section are as follows. In the southern part of section 24 the bluff has straight slopes and failure is by sliding and falls. The beach isnarrow or absent and exposure is reasonably good. There.are relatively few seeps in this section, possibly because of lower infiltration because of fine-grained soils at top. Some minor seeps occur on top of the clay and interbedded sand unit (See. 24, profile 1. Some small slumps are also seated on this clay unit. Approximately.25 miles north into section 24 the slope is covered with concrete debris and there is no exposure. This is a straight slope and is relatively stable except for the concrete blocks that are sliding downhill in .,places. Manufacturing plants are present on the bluff top. North of this (.4 miles N. of section line, the bluff has been graded and grassed. A road comes nearly to the wateri What-is assumed to be a pumping station (oblique R21-33) is protected by sheet pilings. Just north of the sheet piling, a small expssure exists on a straight slope (Oblique R-21-32). ,Material exposed in the vegetation-bare area is primarily debris from grading although about 8 feet of till occurs at the toe and is probably in place. Erosion is taking place here because it is just south of a breakwater. At mile 24.5 (oblique R-21, 31) a breakwater protects the shoreline and a beach 720' wide exists. Most of the bluff is.covered with industrial waste (ashes, unidentifiable material). The Slope is relatively stable and is represented by profile 2. A small pumping station is located at the north end of the breakwater. North to the section line the slope is vegetated with grass and brush. Rubble has been dumped on the slope in many areas. Beach width is 5-20' wide except where the profile was done and here is is poor. At this location a possible light reddish-brown till is present at the top of the bluff. No obvious seeps are present in this area. Section 24 ends at the water treatment plant which is protected by sheet piling. The bluff above this is graded and grassed and appears to be stable. The stratigraphy of section 24 is similar to that in section 25. At the base of the bluff is a gray clayey pebbly till which is overlain by lacustrine sequence. In the southern 3/4 of the section the upper lacustrines are ex- posed at the bluff top but in the northern 1/4 a red brown till caps the bluff. The texture of the lacustrine sediments varies throughout the section. In profile 1 the lower lacustrine deposits are coarse grained sands and gravelswith frequent boulders. To the north the lower lacustrines are massive silts. The upper lacustrine units grade from clay at the southern section line to silt at the northern section line. 9 T.5N., Section 13 The section begins at the waste water treatment Plant which occupies the southern .25 miles of section 13. The plant is surrounded by sheet piling and the slope above is graded and grassed. It appears stable. North of the treatment plant the beach is wide (;@'20') and the upper part of the slope is graded. The slope is straight, partly covered with vegeta- tion and appears stable to 13.5. Just north of this the beach becomes narrower and there is less vegetation on the bluff. At the bluff top, land use is residential. Bluff height is about 100 feet. Profile 1 is typical of.this zone. No large slumps occur and most failure is by flow or sliding. The lower part of the slope is made up of two tills similar in composition (clayey, sandy or silty) with sandy silt between. The upper till (about 40' thick) is overlain by lacustrine silts and clays with sand at'the top. North to 13.8 the stratigraphy and bluff conditions remain the same although the top of the lower till decreases in elevation. Throughout this area (to 13.9) seeps occur at the top of the lower and upper tills and more seeps occur in the clays about 25 feet below the bluff top. A major aspect of slope retreat here is spring sapping which takes place on top of this clay layer and on top of the upper till. Several ravines (13.7) have grown due to this process and also to some extent, surface run-off concentrated at the bluff top. At 13.8 a fill and small docking facility is present. Just north of this the beach is wide (::-20') and the bluff is vegetated (70%) and reasonably stable. No large slumps or failures are present. North to the section line the bluff height drops to 80 feet and the beach narrows to ':-5 feet at the section line. 10 Profile 2 is a slope typical of the unvegetated, narrow beach zone in 13.9 12.0. The same stratigraphy is present as at profile 1 except the silt and fine sand unit between the tills thickens to 38 feet. T.5N., Section 12 Much of this section has fairly low bluff. Bluff height is about 60 feet at the south end and it is fairly flat to about 12.4. This surface is a terrace of Oak Creek and is graded to 640'. Oak Creek enters the lake at 12.5 and more terrace occurs north of this point in southern Grant Park. The bluff then rises to about 90 feet at the north end of the section. The bluff north to 12.25 is covered with flow and slide debris and has a beach 5 to 20 feet wide north to a 900 foot long revetment at 12.1. Above the revetment the slope is partially vegetation covered and is straight. Sliding is taking place with no large slumps. Minor seeps are present on top of the upper till at the south end. North of the revetment some slump blocks (partially vegetated) are present and seated on top of the lower till. Seeps occur on top,of this till in local areas. Much of the toe is covered by slump and flow debris and looks like Profile 1. The.beach is wide 20 ft.) and little toe erosion is taking place north to 12.4. GA c 2 9 .2 Rp- ox c 3 Public sa" PUBLIC PERCEPTION; EROSION HAZARDS 2 Proverzy I I Envifonment 1952 SHORE DAMAGE SURVEY -i.Slo=o (1952) RECESSION RATES f 11 Lalq-Wm-ap;)rox,too)vrs. )(in feet/yr.) 0 ShorT-:@-'n-a;)Prox.I( y". SHORE HEIGHT fintensof feet) SHORE PROTECTION STRUCTURES - - - - - - - - - - - - - HOUSES/MILE- Namurban - - - - - - - - - - BOAT RAMPS ILL tine Co.' Milwaukoe Co. T5N. 60, .4 13 c, 20, _,Z t2A 25 24 .1 13 .SAND S I LIT C 0 V E: P rE DOR Generalized longitudi- INACCESSIBLE nal section showing bluff stratigraphy in Reach 7. Numbers along GRAVEL CLAY TILL base of diagram are geographic (1 mile) sections. SAND ANb CLAYEY' SILTt M I X E: D GRN4EL SILTY. CLAY SEDIMENTS 13 C' A-L T1 ri C@-, C. CIA, 7- S 7. S'\J- Pe. HE k; K 1,7 vA All .9 QAKWOO AK-O -85 Scanlon gc@i '.111:4 C1j k,\ ROAD E 'o Q ughts jj)j@@ -C -,0o,1 Z1, Powerplant C> 11JA 1,;L" cCu--' v @LIL@ r, J ?1. "LID I Ic', . L- @2 Lf 0 jj@-C 0 @J,k. C)Aj- I Ii- ek "LAI" tl-t WOOLD y L Borehole, GT"l Location: Bender Parko @Iilwaukee County, sec. 25, Blo w Counts (Split spoon) Pocket % clay ID Depth Standard Penei Penetrometer wn Yd WL P Clay Silt c c USCS ration vane c lass. (feet) Go vyj .10 1% (psf) % % (psf) ('P0 -5 10 15 14.4 119 23.2 8.6 20 25 14.9 119 23.4 8.1 29.6 87.9 31.4 0.0 CL 30 CL-ML 35 14.1 121 21.8. 7.2 85.2 40 45 27.1 12.4 50 55 1 17.2 112 29.0 12.8 60 65 26.1 10.7 70 29.0 112 24.6 10.6 31.2 91.1 IIA 75 80 20.1 111.5 29.4 10.0 4548 100.0 25.6 1187 85 90 18.8 111.5 26.6 10.9 99.9 CL 95 '100 19.8 107 30.6 15.1 105 110 16.4 114 23.8 9.4 < 20. 82.7 31.0 0.0 CL I@r9 115 120 Ct ML e-k`1 18.0 113 27.7 12.4 93.3 15 T.5N.,R.22/23E.,Sec.31/36 20- SF=.959 50 b ft. B SF=.81 I@SF= 1.38 C B 31- 0- a a 20 .51 ...ft C3 SAFETY FACTOR A-less than 1.00 B- 1. 00 . to 1. 25 C-greater than 1.25 CONFIDENCE LEVEL A-boreholes (high confidence) B-near boreholes stratigraphy visible C-no stratigraphy visible (low confidence) J; i T.5N.,R.22/23E.,Sec.31/36 1. BLUFF a-steeper slopes; @-primarily earth c-compound slope middle portion of_@, flaWage in two failure,slump debris bluff less modi- , . major recognizable fully modified-by fied by flow units, episodes; tops of flowage smaller flow units older flows form more or less contin- uous terrace, younger units cover lower 2/3 of bluff face 2. TOE a-mostly consisting of slumped lacustrine sediments 3. BEACH a-less than 20 ft. sand and b-10 to 20 ft. sand and gravel, gravel widens southward 17 T.5N.,R23E.,Sec.31/36 120- Peof ile 3 "-A 100- B 30 ft.to5ft.depth. gravel s i f s -flow lobe 80- A-B 0% vegetation Lfs important seep zone in B-C 80% vegetation-grass very fine sand 60- C-D 75% vegetation-willows f s D- E 80% vegetation-trees probably lacustrine; willows, scrub 40- concealed by slump concealed. 115 ft.horizontal interruption seeps 20- sand dune 20 40 60 80 100 120 140 160 180 200 220 240 260 280 120- Sr-Z LS-4 Profile 2 100- A seeps 35 ft. to5ft-depth s gravel t 2b) 80@ Si,fs B seeps A-B 0% vegetation B-C 25% vegetation 60- si,fs C-D 80% vegetation flow lobe D-E 80% vegetation 40- seeps 20- D E beach' 20 40 66 8'0 100 120 140 160 180 200 220 240 260 280 120- Profile 1 100- A 41 ft.to 5 ft.depth t major seep zone sand and gravel S,g flow lobe 80- A-B 0% vegetation B-C 60% vegetation j 60- contact transitional C-D 95% vegetation-grass between till and lacustrine sediments s i f S. 40- seeps in lacustrine sediments B @A 20- C D beach 20 40 60 .80 100 120 140 160 180 200 220 240 260 280 T. 5 N.. R. 2 3 E.,Sec. 3113 6 130[ 120 3 2 1 110- 100- s 90- Oak Creek Power Plant 80- v 4 4% 70- LU si,fs LU s i , f s 60- & - wt 00 seeps 50- 40- si,fs 30 Si,fs (n En ? ? Q) seeps Q) I Q) 20- ul 10 0 1000 2000 3000 4000 5000 F E E T 19 T.5E.,R.22E.,Sec.25 C c b b b 20 sF=.68 50 A ft B C S =1.03 a a A 0 20 ft 3 SAFETY FACTOR A-less than 1.00 B-1.00 to 1.25 C-greater than 1.25 CONFIDENCE LEVEL A-borehol@_S__ (high confidence) B-near boreholes stratigraphy visible C-no stratigraphy visible (low confidence) 20 T.5N.,R.22E.,Sec.25 1. BLUFF a-discrete slumps b-small slumps, bluff, no leaving concave lateral spreading large recent slump cuts and scalloped without discrete blocks although older bluff top large slump blocks blocks.probably being truncated shallow slides 2. TOE a-50% till in place b-slumped mixed c-till, most in place 50% lacustrine lacustrine silts silt and till and till slumped 3..BEACH a-5 to 20 ft. beach b-less than 5 ft. pebbles with beach, cobbles, cobbles otherwise no .beach 4. STRUCTURES-none in this section 120- 21 T. 5N. R.22E.,Sec-.25 Profile 3 t 100- 65 ft.to5ft-depth S@g'si cobbles,sand c 0 80- si/fs N.62 E. S19 W Slope 5% vegetation LIJ 60- -Entire sequence maybe si,fs sample I displaced downward slightly [email protected] due to slumping 40- ms kin of debris over slope si/fs 20- beach- t P's 20 40 60 so 100 120 140 160 180 260 2'20 240- 260 120- Prof i le 2 oxidize 100- t 67 ft. to5ft.depth SF=1.00 pebble, cobbles, sand 80- N.640E. 00 F- -100 ft. north of profile LLJ in area between slumps LLJ 60- -typical of bluff between LL slumps -slope 20% vegetated,grass 40- -skin layer over most of SA/fs section 20- seeps at base of small slumps and B=320 flows 20 40 60 so 100 120 140 160 180 200 220 240 2@O 2810 SF=1.24 120- Profile I 100- 67 ft.to 5 ft.depth N.640E. so- -50 ft. N. of section line in slump _jj 60- -50% vegetation section slumped 40- 20- bea ch-cobble,pebble 20 40 60 so 100 120 140 160 ISO 200 220 240 260 280 120 22 T.5N.,R.22E Sec.,25' Plrof i le -100 ft. to 5 ft. depth 80, LLJ LLJ 60- LL@ .40- 20- 20 40 60 80 100 120 140 160 180 200 220 240 .260 280 120 Prof i le 100- ft. to5ft.depth 80- LLI 60- W LL 40- 20- 210 66 80 100 120 140 160 180 200 2@O 240 260 280 120 Prof i le 4 A 100- f t. to 5 f t. d e pt h SF=. 69 80- numerous small slump blocks Characteristic of north LU vegetated seeps of section-,numerous small W 60- slumps without deep cirque LL like cuts 40- slump block __"'@'@numerous sm@ vc 20- boulders-15 ft. J- 130- 2 3 120- 110- 6 4 ioo@- sq,9 c tt si,fs s 80- S19 70- seeps si)fs w LU seeps LU 60- s i , f s L& s ic 501 ms I 40- si. fs 30- s i , f s si,s,g 20- seeps and small slumps q 4 10- a4. h- r-4 0 1000 2000 3000 4000 5000 f E E T 24, T_5N.,R.2'2E.,Se,.24 A 20- .91 50 d' ft B 9 G) - - SF=.623- .81 e jF=. 575 A C 0- e 20 ft. d .51 24 c .41 b b b .21 20 50 SF=.54 ft. a A C 4, SAFETY __LACTOR A-less than 1.00 B-1.00 to 1.25 C-greater than 1.25 CONFIDENCE LEVEL @oles A-bore- (high confidence) B-near boreholes st"tigraPhY visible C-no Stratigraphy visible (low confidence) 25 T.5N.,R.22E.,Sec.24 BLUFF a- 2. TOE a-till in b-broken c-sheet piling d-till in place place concrete fill.behind e-slump debris 3. BEACH a-no beach b-less than c-no beach d-greater than 5 ft., 20 ft.,sand boulders e-no beach f-5 to 20 ft. g-no beach h-5 to 20 ft. wide, pebble wide, pebbles and sand and sand 2& T. 5N. R. 22E. Sec. 24 120 Prof He 3 6 /b 60 ft..to.5 ft. depth 100- sand so- 2 ft.. of rubble _A-B 40% vegetation W sample I UJ 60- A samp, le 2 LL SL 40 sF=.62 slumps and mud flows, 20- si t B broken concrete revetment-no beach 20 40 60 80 100 120 140 160 180 200 220 260 2W 120- Prof He 2 100- i0o ft. to 5 ft. deptl, SF .58 so- N.900E A 3 ft. of rubble A-B 80% vegetation, sample 1 covered by debris W sample la W 60- L'-c I LL t sample 2 40- SF--1.16 si massive mu flows and slumping 20- 0 beach-ms,p,5 slope,26 ft, wide 20 40 66 8'0 100 120 140 160 180 200 220 240 260 280 120- Profile I 100- 90 ft.to5ft.depth 3 ft. sod overhang N.600 E. .80 1811 soil p rofile on top of sand(med-f) si/fs/C W seeps with small slumps Ljj 60 LL S/c 40- c- s 8 e s ps Ow s/c '-t p h r0 sm f a ile on t 'l slum o p p s t s _c ou SF=.54 s/si/ with sporadic bou@de 'dnde*r.cu-tfi@ng of till beach-none 7 n., r-.,.3 ec. Z 4 130[ 120r- 110- 1001 2 3 90 80- soil rubble W 1.- 70- si/s/c 4 Uj seeps-small slumps % L" si,c t 60- ? S C/S 50- 4 ? 44 -4: 4 40- 30 si si 20- s i , s , g b 10- 1 9 @ru bb I @e' 0 1000 2000 3000 4000 .5000 F E E T 28 T.5N.,R.22E.,Sec.13 9 2 SF=.34 d f .82 e C .81 C c 50- .71 100 ft. b b I SF=.38 b .61 13 a 00 SAFETY FACTOR A-less than 1.00 B-1.00 to 1.25 C-greater than 1.25 CONFIDENCE LEVEL A-boreholes (high confidence) B-near boreholes stratigraphy visible C-no stratigraphy visible (low confidence) 29 T.5N.,R.22E.,Sec.13 1. BLUFF a-relatively b-shallow c-protected, d-shallow stable, no slides graded, slides recent relatively failures, stable graded 2. TOE a-slumped, b-slumped, c-in place, d-flow, vegetated, lacustrine till lacustrine now graded silts silts 3. BEACH a-sand,pebbles b-sand,pebbles c-boulders, d-sand,pebbles at water line at water line broken greater than +20 ft. 5 to. 20 ft. concrete, 20 ft. no beach e-greater than f-5 to 20 ft., g-less than 20 ft. 5 ft. 120- 30 100- A 100ft. to. 5 ft. depth S,si --Sample 4 0 N.90 E. 80- SIC seeps C Sample 1 si,-C B No vegetation -60- Sample 2 translational movements 40- Sample 3 S'si seeps 20- slumped mate'rial f s 20 40 60 so 100 120 140 160 180 2M 220 240 260 280 120- Profile2 100- 105ft. to5ft.depth SF=.34 N.900E. 80@ A F=.97 >- Si vegetation only on B-(. 60- S,g B about 20% 1 2- j6 translational movement 40- S Si slump material covered pe + contact 20- f.y Z, C S b T------ T 20 40 60 80 100 120 140 160 180 200 220 240 260 280 120- Profile 00- ft.to 5 ft.depth 80- 60- 40- 10 20- 130- 120- 110- 100- 90 S/Si seeps so- S/C 2 c 1-70- si, s si, c LU S e e S, g Lu 60 - LL. s e e P f,sipc, 50- C.@ .4 40- si, fs 30- si 20- 4 1 V, 10- % *Ai 0 1000 2000 3000 4000 5000 F E E T 32 Field Report - Reach 8 Location This reach is located in Townships 5 and 6 N., Range 22 E., in southern Milwaukee County. It is approximately 6.5 miles long and extends from the beach at Grant Part north to the part of Milwaukee County protected by a breakwater. Land use along the reach varies from industrial in the south to park land and some residential to the north. Reason for Criticality_ The reach ranks #8 in priority in the Erosion Problem Areas list with a value per mile of 12. This value is based on (1) the long term recession rate of I foot per year and the short term recession rate of 2 feet per year, (2) the Corp of Engineers 1952 Shore Damage Survey value of 2 to 3.2, and (3) the bluff height. Reach 8A Reach 8 is divided into 4 parts using the type of slope failure present. The southern most part, 8A, is an area of stable bluff with wide beaches formed by several groins. It extends from the central part of section 12 north to the southern part of section 1, T.5N. (Grant Park). Section 12, T.5N The northern half of section 12 is included in reach 12 and in particular in reach 12A. The area discussed here is in Grant Park and begins at the outlet of Oak Creek (no real bluff is present at the mouth of the creek. North of the creek a groin (structure 12.5) marks the southern edge of Grant Park. North of the groin a large beach and parking lot exists in front of the heavily vegetated bluff which rises to 640'. The beach and heavily vegetated bluff continues north to 12.8 (oblique R-21, 11). 33 Here the beach narrows to about 20 feet and small exposures are present at the base of the slope. It seems likely that this is due to the presence of sand approximately 10 feet thick at the foot of the slope (profile 2). In places it is covered with a veneer of slide and flow debris but in outliers it is exposed in nearly vertical cuts. Undercutting is probably responsible for failure at the slope bottom. The upper slope is vegetated with fairly large trees. The sand is dry where exposed. At the north end of the section the slope is reasonably well protected by groins. Stratigraphy is very poorly exposed on the wooded slopes. Section 1, T5N From the south section line north to 1.4 the slopes are tree covered and stable except for minor undercutting in basal sand unit. In most places this is not exposed. The height of the bluff decreases from about 90 feet at the section line to about 80 feet at 1.4. All of section 1 is within Grant Park. The shore north to 1.4 has a beach 20' wide probably due to the groin at the south end of the section. Reach.8B The second division of reach 8 extends from the southern part of section 1, T5N north to the northern part of section 25, T.6N. In this area the major portion of slope failure is by translational slides and groundwater sapping. Throughout this stretch the stratigraphy consists of a lower gray clayey till separated from a yellow buff to pink silty till by a very thick sand sequence. The bluff height is near 100 feet in this area. Section 1, T5N The conditions present in the area of reach 8B are as follows. North of 1.4, slope failure is taking place primarily by sliding. Several small slumps are seated on silty clay and clay at 60 feet above water level (oblique R 21-2). Seeps are excessive along the top of this unit, probably because of permeable materials along the bluff top. Less well-developed seeps 34 occur at the top ofthe till. Some spring sapping is associated with the slump blocks in the upper sand. At thenorth end of section 1 (profile 3) a thin till is present at the top of the section. This tillis clayey, sandy and gray when unoxidized. -It is buff to pink when oxidized. This till continues to be present toward the north. Section 36, T6N This section has a uniform stratigraphy of till, (gray clayey, sandy) at base between 20 and 40 feet thick. The upper part of this till is less sandy than below. Some pink to red inclusions are present near the base. Above the till lies a persistant unit of silt and interbedded fine sand. It is wet throughout and holds a steep face in some places (profile 2). Above the silt is primarily sand with minor interbedded silt. This unit is about 30 feet thick and is overlain by varying thickness of clayey gray till which weathers to buff-pink (0.12 feet thick). Failure in this section is primarily by spring sapping and flow of sand above the unit of silt. Excellent examples can be seen on oblique photos (eg. R-20, 34). Below the silt slope wash, slides and flows are taking place. No large slumps are present. Throughout much of the section the upper slopes are wooded where sapping has not caused gully formation. Some old gullies have also become wooded. Lower parts of the slope are generally bare because of active sliding due to excessive water from top and within silt. Much of the toe is flow debris. The beach throughout the section is;;,20' except at 36.7, just south of two storm sewer drains which act as groins. In the northern part of the section the bluff has numerous wooded ravines or sapping scars. 35 Section 25, T6N The stratigraphy exposed in section 36 continues into this section, except that a sand unit is present at the toe. The occurrence of this unit is evi- dently coincident with the steepening of the bluff and the excellent exposure. Almost no vegetation is present between the south section line and 25.3 where structures cause an increase in beach width and undercutting of the toe is absent (profile 2). Throughout the section seeps occur above both silt layers although they are not as excessive as they are where only sand overlies the silts (to the south). Sapping does occur in the sand and gravel on top of the lower silt unit. At 25.4 a pumping station has been built just above lake level and the slope is graded along a road down to it. North of the station to 25.6 the beach is 20 feet wide and the slope is about 50% vegetated (primarily the upper part of the slope). Sand still underlies the toe and when the beach narrows under- cutting takes place producing falls of the till above (oblique R-20, 24, Profile 3). Except for ravines, the bluff remains 80-85 feet high with fairly straight slopes and little vegetation. Reach 8C Reach 8C is an area of stable bluff and wide beaches located behind the groin field in Sheridan Park. It includes the northern -1 of section 25 and 4 the southern 1/3 of section 24, T6N. Section 25, T6N At 25.75 a groin field is present and slopes are wooded at the base. Some minor slides are present on the upper part of the slopes. The beach is well over 20 feet wide and thus there is no undercutting taking place. Sheridan Park extends north into section 24. 36 Section 24, T.6N..- Section 24 begins in the northern part of Sheridan Park and continues north for 0.5 miles. North of Sheridan Park crops occupy the field above the bluff. In the southern 1/3 of the section is protected by groins and beach width exceeds 20 feet and the bluff is wooded at the top and base. The central part of the slope is 50% vegetated with shrubs, grass, and occasional trees. No stratigraphy is exposed. Profile 1 shows a typical relatively stable slope. Some flow and slide occurs in the central part of the slope. Reach 8D The northernmost part of reach 8 is an area of steep unvegetated bluffs. The slopes are failing by translational sliding and bluff retreat is relatively rapid. The severity of the erosion could, in part, be attributed to the protective structures'surrounding Milwaukee Harbor. The area extends from the southern part of section 24 north to the electric power plant in section 14. Section 24, T.6N. The conditions present in section 24 north of the stable slope area are as follows. North of 24.3 the beach narrows to less than 20 feet and vegetation becomes sparse. The slope steepens and drops from about 100 feet at pro- file 1 to about 70 feet at profile 2. At the base of the section several feet of sand is exposed, overlain by 10 feet of reddish brown sandy till which is very compact and bouldery. This till has not been seen south of here in Milwaukee Co. Large boulders derived from the till are present along the beach and can be seen on the oblique (R-20, 13) and vertical photos. This till is probably equivalent to the Haeger till. Organics were collected from this unit just above water level. An excellent boulder pavement is present to the north where the unit is overlain by another till. 37 This pavement merges southward with a line of beach gravel which terminates this till and the overlying till. The overlying till is gray, clayey, sandy or silty and is typical of Wadsworth till to the south. Organics are present dispersed in the till. Above the till is of fairly continuous thin layer of sand and sand and gravel. This unit is water bearing and a large number of seeps occur at the base. Undercutting in the gravels occurs especially where the unit is thicker between between profiles 2 and 3 (see longitudinal profile). North of the profiles to the section line, the bluff decreases in elevation to 801 feet. At the section line the bluff top has been graded. Section 14, T6N At the south end of the section and north to the end of the reach (southern extent of Milwaukee Harbor breakwater) the bluff is protected by a revetment and north of that a breakwater around a power plant. Slopes are graded and there are no exposures. North of the power plant there are exposures but these were not examined because they are in reach 12 and this was not designated as critical. 38 N L :@7@7 i7i j. F 36 3 2 A 22 Reach S FIC) 3 Pub(;c safety PUBLIC PERCEPTION: EP.@:SION HAZA S 2 Proppeny I Environment 1952 SHORE DAMAGE SUR-EY-1-31G.000 11952) RECESSION RATES 0 yrs. 0 Shon-tem-approx.loyrs.)(in feet/,,) SHORE HEIGHT (mt-.sof .feet) SHORE PROTECTION STRUCTURES - - - - - - - - - - - - - - HOUSES/MILE- No-url3an - - - - - - - - - - - - - - BOAT RAMPS T 5N. T6N. 100, Cityof Milwaukee -LX @-- -80, C GO' Fbwer Pont 40' li- 07 q- .00 2 B,@ Pic) :e. 71,.,,, 20' 1B I A 12 36 25 24 .14 L E(7% E ND SAND SILT COYERED OR Generalized longitudinal I'MACCESSMI-E section showing bluff ...,stratigraphy in Reach 8. Numbers along base of GJR AVEL CLAY TIL diagram are geographic. (1 mile) sections. SAND AND CLAYLEY SILT, Ni I X ED 17.X =:.4 GRAVEL LILJ -sv-Ty CLAY SEDIMENTS 40 C,@ CA,,,+ P', '14 (Ij t Pi SON( s c 4752 P@AR K 3: R 55, aw 0@ r RA 656,7 Olt Co ur 7, 4j, -Sch A t Ad ert Sc 9 UTIi MIt-WAUKEE so @,I@ -Rail, _E71 Ir6it Hol WT i @FA I ;'4 v@i I 4751 rVica iq I_j E_; 0, @A 2 N., rqu c 4' ET!5 --- 4i er PI kwa OMON. k e ew S h L__L or BM Dis' FJIL VD 180 4750 if- 3, 01 L 4 ON@ C@ur". Borehole: GT-2 Location: Grant Park, Milwaukee County, Sec. 12, T5N Blow Counts (split spoon) Pocket % Clay w Y w I % Clay c c USCS, iepth Standard Penetration Penetrometer n (P81) % L %P & Silt vane class. feet) %D Qo W "Ii.) eio tcvr@ Lk % (Dsf@ (Dsf) 10 1.5 20 .4.2 117 8.3 38.6 0 SP 25 30 35 40 7.0 45 16.8 120 19.0 3.6 8.3 99.8 VAL- Ygi 50 O-AAL 55 17.0 115 22.7 7.9 25.8 99.8 60 42 3 C,,jJ+'tj, K.L" I4A Pk, A.Jc'l 23 @j ki yf Is L- 14@ stc Z4 ov, Ik zz p 4 -:,wq Powerpla6t-' Thomp h .;Ap 71 21 W -I&IT-F AN, -C IS EE-NE PARK f7 sch :1 PARK Lu vj@ AVF 7 700 ! j M, Ll In 1157 c, _@ch A 1--BLVDIIF F, 0 ch .................. CD L POI Fer,-ck-c L.YTO IL -17 57'3011@'- \,4 I@-W% Borehole: OT-3 Location: Sheridan Park, Milwaukee County, Bloj,r Counts (SpliL spoons' Pocket % Clay c c USCS Depth Standard Penet'ration Penetrometer wn Ydfj WL IP % Clay & silt vane class. (feet' % (Ps % % (I)Sf) CPsfj 6.4 140 10 ML 15 10.1 13.0 17;1, 4.6 20 12.2 129 d@i@li g haltz-A 20 fe(t du@ to slimp.ng slope !fa e s mp@e -)ae f ID1 If f 4.8 125 non-plastic <10 31.8 34.6 0 5W Canll@ 44 T.5N.,R.22E.,Sec.12 SF=.82 B C .81 (2) 0- 20 ft. e e d 12 d 51 d .42 .41 c c c SF=.98 B C 0- b b b 20 f a a a Q lk@ 4@7 A_@ SAFETY FACTOR 40 A-less than 1.00 co B-1.00 to 1.25 C-greater than 1.25 CONFIDENCE LEVEL A-boreholes (high confidence) B-near boreholes stratigraphy visible C-no stratigraphy visible (low Confidence) 4@ T.5N.,R.22E.,Sec.12 45 1. BLUFF a-shallow b-relatively c-shallow d-relatively stable slides stable - slides protective struc- protected ture and wide by revetment beach graded and wooded slopes responsible 2. TOE a-in place b-broken c-toe material d-toe material not concrete not visible visible nothing slope graded natural visible e-in place sand and boulder layer 3. BEACH a-5-20 ft. b-concrete c-+20 ft. d-concrete sand revetment revetment no beach no beach, e-+20 ft. sand 120- 46 T.5N.,RME.'.,Sec.l2 Prof i le 100- ft. to 5 ft.depth 80- 60- 40- 20- 20 40 60 so 100 120 140 160 180 200 220 24.0 260 280 120- Prof i I e 2 100- 65ft. to5ft.depth sand 80- SF=.82 i6,0 % vegetation trees, bushes, grasb. 60- c 40- Z sample I t sample 2 100% veptation 20 c,-s,g,b- trees, bushes, grass S 40% vegetation r------ T- I --I 2 40 60 80 100 120 140 160 180 200 220 240 260 280 120- Profile I 100- 80 ft.to 5 ft.depth 80@ sample 1 60% vegetation 60- sample 2 ith mud flows C- --ap- eep L 40- 100% vegetation E-T- 0 t ith mud flows SF=.78 20- 100% vegeta.tion S ty 07 vegetation,slump ' o .I a I blk. 130- 120- 2 110- 100- 90- Dense MS/Si 80- vegetation 70- LU Terracing C'Si 60- si,g,y 50- ms seeps P 4 40- 2 f 30- 4 w I I vD 20- eVs-,- Sils C, Igib 10- ms Den e g / s ve etatio racing 0 1000 2000 3000 4000 5000 F E E T T.5N.,R.22E.,Sec.l 48 SF=.40 e 75- 100 ft. A B b .51 SF=. 5 1 a c -SF=.49 b A: C a 20- 50 a ft. GT-2 61 SAFETY FACTOR A-les@ than 1.00 B-1.00 to 1.25 C-greater than 1.25 CONFIDENCE LEVEL A-boreholes (high confidence) B-near boreholes stratigraphy visible C-no stratigrBphy visible (low Confidence) 49 T.5N.,R.22E.,S6c.l 1. BLUFF a-stable b-primarily vegetated, slides, no recent several failures shallow slumps 2. TOE a-sand with a b-slumped silt, c-sand, in d-slumped tree, bush sand with place material and grass pebbles, -cover in pla.cc cobbles and boulders -mudflows throughout 3. BEACH a- +20 ft. cobbles and pebbles grading into sand SF=. 92 SF=. 62 50. T.5N.,R.22E.,sec-I 120- Profile.3 t SI, S 100- c 27 ft.to5ft-depth s,si/s,c cearse gravel 80- s g s4Lepg_ 60- c SF=.40 50% vegetated si grass, trees 40- t 20- beach 20 40 60 80 100 120 140 160 180 200 220 240 260 2aO 120- Prof i le 2 100- A 67 ft. to5ft.depth B sand 80- S/g,sl 60- seeps SF=.51 si,c no vegetation 40- S/si seeps on slope sample I 20- t beach D 20 40 60 80 100 120 140 160 180 200 220 240 260 280 120- Prof i le I 100- 65 ft.to 5 ft.depth sand 80- S/si 20% vegetation trees shes, grass Cos 60- seeps 40- c.si 90% vegetation SF=.49 20- sample I beach 130- 120- 2 3 110- 100- 90- eavy vegetation 80- ms/toi S'si ms 70- ms/g Cfl I.- LU See We Lu60- cs e ess c 50- C'Si si 40- S'si inor Seeps Si,c 4 30- 20- f 10- f %4 ss@-,-je _e 0 1000 2000 3000 4000 5000 F E E T 52 T,,6N.,R.22E.,Sec.36 2o- 50 ft. A c C -SF=.54 .72 .71 b b 36 0- 20 B C ft. CD SF=I. 19 a .21 20- 50 A ft (D- - - SF=. 50 '5" SAFETY FACTOR A-less then 1.00 1,61J, 25 B-1.00 to I. C greater than 1.25 _ CONFIDENCE LEVEL A-boreholes (high confiden-ce) B-near boreholes stratigraphy visible C-no stratigraphy visible (low confidence) 53 T. 6N. , R. 22E. , Se c.36 1. BLUFF a-the entire section has shallow slides with the exception of several major slump blocks,flows and ravines due to spring. 2. TOE a-slumped silt, b-in place c-slumped silt, soil and till sand till 3. BEACH a-greater than b-5 to 20 ft., c-greater than 20 ft.,sand sand and 20 ft.,sand with pebbles pebbles, with'pebbles and cobbles cobbles at and cobbles at high wave high wave at high wave line. line line 180- 54 T..6N. R.22E. sec3( Profile 3 6 150- -110ft.to5 ft.depth sand 120- A SF=1. 19 earthflow failure T W 0% vegetation W 90- B U_ s 5% vegetation 60- M_ 90% vegetation 30- D E 0% vegetation 30 60 90 120 150 180 210 240 270 300 330 360 390 420 120- Prof He 2 100- 80 ft. to5ft.deptl A sand -S,SL,t - sample I 80- t- - sample 2 N. 98 E:_.@ si B s 0% vegetation W 60- C W SF=.54 LL seeps D 40- si segps E 20 -1 5% vegetation sample 3 translational failure t beach- p, y 20 40 60 80 100 120 140 160 180 2@O 2@O 240 260 290 120- Prof He 100- 40 f t. to 5 f t. dept h gravel A t sample I N. 80 Ez._@ 80- t/S T B 0%,ve5zetation translational failur, W seeps T W 60- 20% vegetation S/si/c U_ s seeps 40- sc C SF=.50 see- 90% vegetation 20- t1c's D 10% vegetation E beach- S, y_301ft. wide 5 slope T_ 7 -1 1 -1 1 1 1 1 1 130- 120- (No stratigraphy) 3 2 110- 100- 90- C., 80- s si 70- LU s LU 60 - 50- s and sapping excessive seep Si 40- Silfs 30- Seeos f'C'S'Si 20- 10- S.. V ,e 1004, 101. S @e eps 0 0 1000 2000 3000 4000 5000 F E E T 56 T-6N.,R.,22E.,Sec.25 20- .91 50 d d ft. SF=. 88 A B 50 75 C C. 25 SF--.49 ft. .41 0-, Q- - SF=.68 10 .32 ft. .31 A B 50 a SF=.33 75 ft. SAFETY 'FACTOR A-less-t-han 1.00 B-1.00 to 1.25 C-greater than 1.25 CONF' !eNCEl LEVEL A-b 0 es (high confidence) B-Rear boreholes stratigraphy visible C-no stratigraphy visible (low confidence) 57 T. 6N. . R. 22E Sec. 25 1. BLUFF a-few large b-affected by c-few slumps, J-thick slumps,major structures, clean slope, vegetation, seeps cause slopes more no vegetation more gentle deep ravines vegetated less sapping slope,tiees due to sapping (507. grass), than southern cover nearly excellent less sapping part probably 100 % exposure more flow due to till (some flow cap, many cuts terraces at due to surface base), a few runoff slumps 2. TOE a-25% under- b-sand not c-25% sand I-all flow cutting in exposed,flow exposed, debris, 100% sand, terraces of remainder is vegetated, remainder thin till and unvegetated, 6 to 15 ft., flow, no lacustrine fresh flow medium'sand vegetation, silt,vegetated debris,till, at base slide debris, 6 to 15 ft., silt,6 tol5 ft. mainly till, medium sand medium sand at 6 to 15 ft., at base base medium sand at base 3. BEACH a-greater than b-5 to 20 ft., c-greater than d-5 to 20 ft., 5 ft.,pebble.s pebbles at 20 ft.,pebbles pebbles at at waters water'.s edge at water's water's edge edge, sand sand to base edge, sand to sand to base to base of of bluff bluff of bluff bluff e-20 ft., pebbles at water's edge, sand to base of bluff 58 T.6N.,R22 E.,Sec. 25 120- Profile 3 61161176 100- 50 ft.to5ft.depth 80- c si seeps N.600 E - si/fS -no vegetation -translation -minor sapping near fg's b,y pavement top cog @seeps SF=.49 -boulder layer, 40- ' '_@r probably beach s sample I -gravel looks like 2171S t'c'S '7, beach at base, 20- possibly higher s,med old water level beach-s,p 32 ft. wide, 100slope 20 40 60 80 100 120 140 160 180 200 220 240 260 280 120- Profile 2 100- 60 ft. to5ft-depth N.700 E. so- sample I SF=.68 -50% vegetation si/fS -between groins 60- -no major sluipp, tran S-mco lation, sapping 9's seeps (less intense than profile) 40- C'si t,c,p sample 2 S, sample 3 20- t,c, / some small mud flow terraces, sand.generally S-M, /beach- s,p 20 ft. wide, slope 70 covered I I I 20 40 60 so 100 120 140 160 180 200 220 240 260 280 120- Profile I 100- S-m- 70 ft.to 5 ft.depth t'si '2_ sample 3 80- S-M __ N. 6 00 9's . -no vegetation c si's sample 2 -some small slumps, I/S-f 60- si. m mostly translational t,C,S,y -skin layer 1-2 ft. sample I SF= .33 thick in places eps 40- si/fS _jt -extreme sapping at 91S gravel 30 ft. below surface. 20- t,c)si,s)y S-M no beach(boulders@ T.6N.,R.22E.,Sec.25 120- t 59 Profile4 100- 85 tt. to b f t depth t'c'si Minor N-90'E 80- ___@eeps 8S Si fs.S -1.0% vegetation,grass. s -failure by sliding 60- fg,s -some sapping at minor base of gravel cog seeps -clean surface 40- si/fs t,c,s (2 E) 20- S-mco beach-s,p 18 ft. wide, 60slope 20 40 60 80 100 120 140 160 180 200 220 240 260 280 120- Prof He 100- f tto 5ft. depth 80- 60- 40- 20- 20 40 66 8'0 100 120 140 160 180 200 220 240 260 280 120- Profile 100-4 ft.to 5 ft.depth 80- 60- 40- s ste2s (2 @E' 20- 20 40 60 80 100 120 140 160 ISO 100 220 240 260 280 t 6 N..R.22E.,Sec.25 130- 120- 110- 1 2 3 4 100- ---1 1 1 1 s Wooded f si. P 90- 4 4 ms 80- c 9 1-70- Ssi s,fs LU f,c'* si,fs 60- Slb fg L& si, s f g 4 f g 50- 1. 0 - f S)fg cog 4 seeps cOg seePs 40- si's si, c sis g's 30- fic f f 4 9. 20- f -------- 4 10 s s s s II I I I I s f's C Wooded 44 sils --7 0 1000 2000 3000 4000 5000 F E E T 61 T.6N.,R.22E.,Sec.24 50 75 S F=. 3 9 ft b C b C 24 GT-3 SF=.38 b .31 2 5 SF= f ap roxB C a a a tO SAFETY FACTOR A-less than 1.00 41 B-1.00 to 1.25 C-greater than 1.25 CONFIDENCE LEVEL A-boreholes (high confidence) B-near boreholes . stratigraphy visible C-no stratigraphy., visible (low confidence) 62 T.6N.,R.22E.,Sec.24 1. BLUFF a-relatively b-shallow slides stable no translational recent movement only, failures,well very steep protected by slope 9 Droins . TOE a-slumped till b-in place c-in place sand till 3. BEACH a-greater than b-5 to 20 ft., 20 -ft.,sand sand and gravel with cobbles and boulders. T.6N.,R.22r,-.,Sec.24 120- 63 Profile3 100- 53 ft.to5ft-depth N.700E so- boulders and cobbles 6.0- A -translational S,@i___ -seeps- failure si,c !@F= -0% vegetation 40- s excessiv- seeps S,9,Y ____ 20- t,c IB sample 1-organics boulder layer,---- - sample 2,sample 3- organics t's C beach-s,y, 12 ft. wide 70slope 20 40 60 80 100 1*20 140 160 180 200 220 240 260 2@O 120- Profile2 100- 60 ft. to5ft.depth N-70'E so- A t (;Z, , . . 20 % vegetation -translational 60- B covered slope f ailure s i f S 70% vegetation excessive seeps s 40- sand lens 20- D 07. vegetation s s g S-1 t's I talus slope s - - - - - - beach-s,y, 20 ft. wide 50slope 7 1 1 1 1 1 1 1 20 40 66 80 100 120 140 160 180 200 220 240 260 280 120- Profile I 100 53 ft.to 5 ft.depth N. 60 0 E 80- 80% vegetation -no recent failure slope covered by 60- flow and or vegetation- P 40- A c @ee ps exce SSIV s 'y B sampl t'c X er laye t sa U e,i L 20- beach-s,g,y, 100ft.wide 5 Oslope 20 40 60 so 100 1:20 140 160 180 200 220 240 260 280 120- 64 T.6N.,R.22E.,Sec. 24 Profile 100- tt. to 5 f t. depth 80- A A 60- A- 40- 20- 20 40 60 80 100 120 140 160 180 200 220 240 260 280 120- Prof He 100- ft. to5ft.depth 80- 60- L 40- 20- 20 40 6@ 810 100 120 140 160 180 200 220 240 260 280 120- Profile4 100- ft.to 5 ft.depth 80- -translational failure j 60- -0% vegetation B 40- A B-C slope,lall d ebris 20 c beach-y, 15 ft. wide, 80slope 130- 120- 110- 2 3 100- f4 4 90- 80 j..70- s 60- f W6 50- si,fs si, s 40- s si?C s 4 4 ST9 small 30- SFUMPS seeg 20- f 2 S, si 4 V@.' 10- s ie-p ;7 -b paveme * nf f,c)S la g, s 0 1000 2000 3000 4000 5000 F E E T T.6N.,R.22E.,Sec.14 66 North edge of reach 8 d .31 NA NA a a c NA b SAFETY FACTOR A-less than 1.00 B-1.00 to 1.25 C-greater than 1.25 CONFIDENCE LEVEL A-boreholes (high confidence) B-near boreholes stratigraphy visible C-no stratigraphy visible (low confidence) T.6N.,R.22E.,Sec.14 67 1. BLUFF a-ali gra6ed, grassed and stable 2. TOE a-all protected 3. BEACH a- -5 ft. b-against c-protected- d- -5. ft. to revetment no beach revetment 12 GA 2 T4 13.2 17 3 r-' 7i -7 -7-7- 7 A -77/ IK 4, F-l i 4- L N I?eo,c 3 PUblit 309ty PUBLIC PERCEPrIO.WERSSION HAZARDS[ 2 Pro-,ernj I E@ironment .1952 SHORE DAMAGS SI.;R,.SY -1-SIG= JIM21. RECESSION RATES f8 L=rg.;wm-apprcx-l00 "Jui Short - term-approx.10 yrsn SHORE HEIGHT la"timsef 19*0 K@ SHORE -PROTECTIO*4 STRUCTURES - - - - - - - - - - - - - ftft-wft" 69 @Field Report on Reach 10 Location Reach 10 is located in Townships 7 and 8 North, Range 22 East, in northern Milwaukee County. The reach is about 6.5 miles long and extends northward from the Waterworks at Lake Park to Fox Point. Land use in the reach is limited to residential areas (Shorewood, Whitefish Bay, Fox Point) and Parklands (Shorewood, Buckley, Big Bay, Silver Spring, Klode, and Doctors Parks). Reason for Criticality Reach 10 is ranked #6 on the Erosion Problem Area priority list having a value per mile of 20. This value is based on (1) the long term recession rate that varies from 20 to 30 ft. per 100 years; (2) the Corps of Engineers 1952 Shore Damage Survey value of 1.2 to 16.2; and on (3) the Corps of Engineers list of critical erosion areas. Reach 10A Reach 10 is divided into 5 parts based on the slope conditions of the bluff. Part 10A at the southern end of the reach (includes section 10 and I of section 3) is a stretcli of very stable bluff, heavily woode d bluff. 2 T.7N., Section 10 Section 10, the southernmost section in reach 11 begins at the Water- works in Lake Park. The plant is built entirely on land fill and is pro- tected by a seawall constructed of sheet piling. The slope above the land fill is graded and grassed. Immediately north of the.Waterworks, the bluff is very low, 40 to 60 feet and is well protected by a very wide beach (50 ft.) formed by the groin like action of the landfill seawall. The slope is gentle and tree covered. Northward the bluff height quickly increases to 100 feet (10.,15) and th en to almost 120 feet (10.2). At the same-time the beach width decreases from 50 feet to only about 20 feet. At 10.2 a sea- wall and groin corbination protect the toe. These protective structures 70 function well to 10.4. At this point an older seawall which has been overtopped, collapsed, and undermined fails to protect the toe,, causing an 8' scarp to be formed. The material visible at the scarp is slumped soil. The upper slope is wooded and appears stable. The old seawall continues with several interruptions to the end of the section. The first profile at 10.65 shows what appears to be a stable slope with its toe p�otected by a seawall (R-18-9). The bluff height is 116 feet 0 and the angle of slope is 17 . There is no beach, instead a few cobbles and boulders protect the seawalling from being undermined. The vegetative cover was 10076 before the property owner clearcut the bluff slope; at pre- sent the cover is 50% (low grasses and weeds). Although there is no noticeable erosion in this profile on the adjacent property owners land there is a large deep seated slump block. The slump block is marked by a six to eight foot scarp. Boring logs from Soil Testing Services, Inc. indicate that the upper red till extends to a minimum depth of 60 feet. At 10.7 a small terrace begins, and extends north to 10.9. It reaches a maximum width of over 200 feet at 10.8. The seawall is absent at 10.8 and the resulting eroded toe exposes 6 feet of sandy, clayey blue-gray till. At 10.85 another small exposure shows 4 feet of sandy, clayey, blue-gray till over which lies 3 feet of gravel and 4 ft. of medium yellow buff sand. At both of these exposures a small 5 ft.) beach of cobbles is formed. A collapsed seawall at 10.9 is the site of the worst erosion in section 10. A 50 foot section of the seawall is collapsed and another 100 feet is seriously overtopped (R-18/6). The property owner, in an effort to pro- tect his house, has dumped a large quantity of fill over and on the bluff. This is the first part of the section that is devoid of vegetation. There are several small scarps (2 feet) marking the location of several slump 71 blocks within the fill material. The bluff height at this point has decreased to about 80 feet. From this location to the end of section 10 a functioning seawall protects the toe of the steepest slope in the section (27 0 The vege- tation on the slope is 8076 to 100% and contains several large trees. The last 50 feet of the section has a sand beach that widens to about 25 feet. The presence of seepage was not noticed, although the groundwater may be responsible for movement along the failure planes of the slump blocks. The use of the bluff top is entirely residential in this section. T.7N., Section 3 Section 3 starts at the southernmost groin in Shorewood Park. The bluff height at this point is 76 feet high as indicated in profile 1. The slope is relatively stable (27 0) and completely grassed. Three groins at the park .have built a wide (80 ft.) beach which protects the toe of the bluff. North of the park the slopes are covered with trees (m.aple, basswood, ash, cherry, willow, poplar, oak and locust) with diameters up to 15 inches. The slope is stable and the beach wide (40 ft.) north to 3.35. Profile 2 at 3.35 shows a stable 24 0 slope protected by a wide beach 20 ft.) and a small seawall. The bluff height is 80 feet and the vege- tative covering is 100%. There is no evidence of seepage. Reach 10B Reach 10B is an area of unstable bluff which is characterized by both translational sliding and by rotational slumping. The area extends from the middle of section 3, T.7N., north to 21.8 T.8N. The bluff height in 10B varies from 70' to 80' in sections 3, 33, and 28 (T.8N.) and rises to about 120' in section 21, T.8N. The general stratigraphy of reach IOB has an upper red brown silty till separated from a trio of lower tills by a sequence of silt and interbedded 72 silt and sand. The thicknesses and the position in the bluff of the till and lacustrine sediments is variable and is best viewed on the longitudinal profile. Throughout the reach two types of slope failure were evident.' In one type rapid toe erosion of the bluff causes steep lower slopes and shallow translational slides on the more gentle upper slopes. In this case the toe material was usually in place (lower blue-gray sandy till or silt) or less often there was a small quantity of upper red till or silt debris covering the toe. (The slide material was carried away as rapidly as it fell). This type of failure is limited to the very active slopes. Slumping, the other type of failure, is caused by toe erosion coupled with the presence of seeps and lubricated rotational failure planes. Slopes exhibiting this type of failure usually have large blocks of slumped debris (out of place) covering the toe. This characteristic is due to the fact that the slump blocks pile up at the base of the bluff faster than they are re- moved by wave action. The topographic profile shows a gentle lower slope and a steep upper slope. Rotational slump scarps were observed on even the most stable appearing slopes such as those protected by seawalls, groins, and terraces. Throughout the reach several minor seeps occur in the lower part of the bluff either on top of the lower blue-gray clayey-sandy till or over. a less permeable silt or clay layer. The presence of the seeps with their sapping action does not add greatly to the erosion problem. Their major contribution is in reducing strength along-failure planes. The beach conditions in the reach vary greatly depending on the pro- tective structures, Where groins exist wide (60 ft.) sand beaches pro- tected the slope. Where seawalls exist there is a small sand and cobble beach or none at all. Revetments usually have no beach. 73 Section 3, T.7N. The northern of section 3 is markedly different from the southern.12' The bluff height increases, the beach width decreases and the slope becomes very unstable. North of profile 2 the beach narrows and the bluff height increases. At 3.5 the beach is 5 feet wide and the toe of the slope is being rapidly eroded. The vegetation is limited to the upper J of bluff and the lower 12 is marked by continuous shallow slides. The first in-place stratigraphy of section 3 was located at 3.55. Here a blue-gray sandy till with many- cobbles and pebbles is exposed just above the lake level. Above this till is an intermediate till which is blue-gray, silty and not as pebbley as the lower till. On top of this intermediate till is a brown-gray, clayey till with a high shale pebble content. The thicknesses of the tills is as follows: lower blue-gray, sandy till - 12 feet thick; intermediate blue- gray silty till - 8 feet thick; brown-gray clayey till - 5 feet thick. Above the 3 till units is a thin 4 ft. thick layer of silt and sandy silt. The silt lAyer marks the top of this exposure. The cobble beach widens slightly (5 to 20') and the bluff height in- creases to 108 feet at 3.67 (profile 3). Only the upper 1/3 of the bluff is vegetated (9070 giving a good exposure in the lower 2/3. At the base of the exposure and extending 28 feet above the water level is a sequence of highly oxidized interbedded sands and fine gravels (2' dia.). Above this layer is a 10 foot thick layer of blue-gray, silty till with frequent boulders and a high gravel content. Above this unit is a brown- gray clayey, shaley till about 4 feet thick and a silt layer about 4 feet thick. These lower units form the steeper (40 0) lower slope which is being rapidly eroded by wave action. It is thought that the lower sandy till is below the water level and that it is the intermediate silty till which is exposed over the sand and gravel layers. 74 The more gentle upper slope (29 0) is composed of a red brown silty till which extends up to the bluff top making the layer 70 feet thick. The till in this layer is subject to shallow translational slides, with the base of the slides being at the red till - silt contact or at the brown gray till silt contact. The upper limit of the slide scars is about 80 feet above lake level or about 52 feet above the base of the slide zone. No springs were observed at the profile 3 location. From profile 3 at 3.67 northward to profile 4 at 3.87 the beach retains its 5' to 20' width while its texture changes from cobbles to sand and pebbles. The bluff height decreases to 72 feet and all of the stratigraphic layers dip to the north making them appear lower in the bluff. Profile 4 located at 3.87 has bluff height of 72 feet and is vegetated only on the upper 1/3 (80%). The sequence exposed has the intermediate blue- gray silty and gravelly till at the base and extending 10 feet above the water level. (The thick sand and gravel unit exposed at the base of profile 3 is not visible at this location). On top of this till is 6 feet of brown- gray clayey till with a high shale pebble content.. Over these lower tills and separating them from the upper red brown till is a lacustrine sequence including 4 feet of silty clay and 12 feet of pinkish brown silt. Above the pinkish brown silt is the red till, which extends 40 feet to the bluff top. The shape of profile 4 is similar to profile 3. Wave action eroding the toe of the bluff has caused a steep lower slope (51 0) triggering shallow translational slides which are responsible for the upper more gentle slope (30.50). The break in slope occurs in the silty clay and is coincident with the occurrence of several minor seeps. The fact that the break in slope occurs much lower on the bluff in profile 4 than in profile 3 can be attributed to the impermeable silty clay and blue-gray till appearing lower in the bluff. Northward to the end of section 3 similar conditions exist, the only changes are that the stratigraphic layers rise causing the break in slope to rise also. Most of the bluff top is used as a residential zone. 75 T.8N., Sections 33 & 34 Sections 33 and Mare considered together because their combined length is only that of a normal section (the shore line just cuts a.corner of sec- tion 34). The section line marking the southern extent of sections 33 and 34 runs along Hampton Avenue. Best access to the bluff and beach is through Big Bay Park. From 34.0 to 34.2 the bluff height is about 70 feet to 75 feet. There is a 5 to 20 foot beach of sand and.cobbles and almost no vegetation. Toe ero- sion is rapid causing steep lower slopes and shallow translational slides on the upper more gentle slopes. At the base of the bluff is the blue-gray sandy and gravelly till which is separated from an intermediate blue gray silty till by a boulder pavement. Over the silty till is a layer of brown gray shaley clayey till. The lower three tills are separated from the upper red brown till by a lacustrine sequence of silty clay, sandy silt and a widening wedge of sand. The thicknesses of all of these lacustrine layers increases toward the north, to profile 1 at 34.2. A stone filled steel crib at 34.1 is intended to protect the bluff toe from wave action but has failed completely due to flanking and overtopping. Minor seeps occur at the base of the medium sand at the base of the sandy silt. These springs reduce friction along failure surfaces but are not responsible for sapping on any large degree. A seawall partially protects the toe of the bluff at about 34.18 caus- ing the slope to be more highly vegetated. The upper 2/3 is 10070 covered while the lower 1/3 is bare of vegetation. The failing seawall extends in part to 34.2. It is here that profile 1 was drawn. The bluff height at profile 1 is 76 feet and the vegetative cover is 80% on the slope with the slide scars consituting the 2076 that is unvegetated.. The stratigraphy of the profile includes a blue gray sandy gravelly till extending from the water level to a height of almost 20 ft., followed by an 8 76 foot. thick layer of blue gray silty till and a 6 foot thick layer of brown gray clayey shaley till. These layers form the steeper (44!@) lower slope where the more rapid toe erosion is occurring. Above the tills and their corresponding break in slope is a massive gray silt about 16 feet thick, a gray sandy silt 10 feet thick, a medium sand 8 feet thick, and the red till 8 feet thick extending to the bluff top. This sequence of lacustrine deposits and till form the more gentle (27') upper slope. The slope failure scars are present all of the way to the bluff top in this profile. Several springs occur above the lower clayey till in the massive gray silts. These contribute to the translational slides present on the upper slope. Within the upper slope more seeps occur at the base of the medium sand, but are not responsible for any increased rate of slope failure. The beach at profile 1 is of sand 15 feet wide. This continues to 34.22 where a revetment protects the slope. Behind the revetment the slope is covered with fill debris which is subject to slides and slump in the near future due to its very steep slope. Starting at 33.25 and continuing north to 33.45 a seawall protects the bluff below Big Bay Park. In this stretch the slope is 3V@, relatively stable and completely vegetated (1007o weeds and trees up to 15" in diameter). The bluff height is 69 feet and the beach is nonexistant except where a groin has been added to the seawall (33.3). This area of the bluff and shore is depicted in profile 2. North of 33.45 the seawall is collapsed and the stratigraphy is exposed. Profile 3 (33.55) is typical of the bluff to about 33.63. The bluff height has increased to 86 feet and the beach width is 15 feet (pebbles). The vegetative cover is 1007o on the upper 1/3 and 076 on the lower 2/3 of the bluff. The same stratigraphy is found in profile 3 as was described in profile 1, with the exception that the lowest blue gray sandy gravelly till is not present due to an overall lowering of the beds. At the base of the bluff is a 4 foot thick 77 layer of silty blue gray till and a.2 foot thick layer of brown gray clayey till. The tills are overlain by 25 feet of pink silts and 13 feet of interbedded gray clay, gray silt, and fine sand. Above these layers is 19 feet of cross bedded fine and medium sand and 23 feet of red brown till. The lower tills are covered in most places by slide debris which forms the low angle (250) lower slope. The pink silt, gray clays, wilts, and fine sand and the crossbedded fine and medium sand hold a second and steeper slope (47'). It is this slope that represents the cutting action of the waves. The upper red brown till forms a third break in slope with an angle of 220. This layer is being undermined by the rapidly eroding lacustrine deposits and is subject to translational slides. Seeps are located in this profile above the lower gray till and above the gray clay, silts in the medium and fine sand. Both of the seeps are minor. At 33.6 the slope configuration changes in that the shallow slides are no longer the major slope failure form. Here large deep seated slump blocks are present. The rotational failure planes extend from the top of the bluff to the lake level. The photos 17 and 18 (roll 17) show the large slump blocks resting at the bottom of the bluff (note the jumbled lean of the trees) and the rotational failure plane extending from the bluff top to the lake level. This stretch of shoreline should be very active in the near future because of the concentrated erosion focused on the area by the protruding Monestary structure. At the monestary (33.7) an extravagant protection device was constructed by Foundation Engineering, Inc. It consists of a poured concrete seawall supported by wooden pilings with fill material placed behind it to stabilize the slope, (photo 18, roll 17). At this time protection against flanking seems inadequate. 78 North to the end of the section the bluff height decreases to 70 feet while the beach varies from 5 feet to a maximum of about 25 feet. This entire stretch of shoreline is affected by large rotational slumps with rapid toe erosion and shallow translation slides being added to those areas with narrow beaches. Other than Big Bay, and Buckley Parks, the section is residential. Section 28, T8N Section 28 begins at Silver Spring park. Best access is through either Silver Spring Park or Klode Park. The bluff top use is both residential and parkland. The conditions present at the beginning of the section continue north to profile 1 (28.24). The bluff height is about 70 feet (73 feet at profile 1) and the beach is 25 feet wide. In the zone of breakers the beach is of cobbles and beyond the line of waves the beach is sandy. The vegetative cover is about 90%. At 28.14 there is a very large stretch of bluff marked by a success ion of slump blocks. Silt is exposed at the toe but this is slumped material. Numerous springs were observed on either side of slump blocks and standing water was observed on the rotated back edge of the lower slump blocks. Profile 1 located at 28.24 shows a close look at the stratigraphy which has varied considerably from that in section 33. At the base 13 feet of silty clay is overlain by 7 feet of silt and 33 feet of interbedded sand and silt. Over the sand and silt is the familiar red brown till (19 feet thick). The blue gray, and brown gray tills, having dipped to the north, are not exposed. Also the crossbedded medium and fine sands below the red till in section 33 have pinched out and are replaced by the thicker sequence of interbedded sands and silt. Several flowing seeps are located at the contact between the inter- bedded sands and silt and the less permeable silt. 79 The.topography of profile 1 was interesting in that a large mound of slumped till, silt, and sand had rotated to a point 45 feet in front of the toe of the bluff. The slumped material had a sttep toe and a gentle back slope which descended to the true bluff toe. The lower slope of the bluff is in place.silt and silty clay covered by a veneer of slumped till. This part of the slope is inclined at 230. The single break on the bluff slope occurs at the top of the silt layer about 19 feet above lake level. Above this point the interbedded silt and sand and the red till hole a bluff face angle of 400. At the top of .the bluff is a small overhanging escarpment. Failure was due to toe erosion and slumping along ground water lubricated planes. From profile 1 (28.24) north to profile 2 (28.25) the beach remains constant (25 feet wide) and the bluff height increases from 73 feet to 82 feet. With the increase in bluff height the stratigraphic layers are exposed higher in the bluff. At profile 2 (28.25) 21 feet of silty clay is exposed at the base of the bluff with 8 feet of silt over it and 32 feet of interbedded silt and sand on top of the silt. At the top of the bluff is 20 feet of red till. The topographic profile here is similar to the first in this section. The lower part of the slope is a gently sloping (200) debris pile. The upper part of the slope is a more steeply sloping (400) and marked by several (4) small escarpments. The slope is 40% vegetated. Slope failure is due to rapid toe erosion and slumping Along the silt and interbedded sand and silt contact where flowing springs were numerous. These conditions prevailed north to Klode Park (28.4, photo 27, roll 17) where the beach widens and the slope is graded and grassed. The bluff at the park is stable. However north bf the park the s*lope steepens and becomes unstable again. The beach narrows to about 25 feet and the bluff height remains slightly over 80 feet. At profiles 3 and 4 the stratigraphy and slope was measured in an effort to compare a slumping unvegetated slope with a highly vegetated more stable looking slope. 80 Profile 3 the slumping area is about 5076 vegetated. Its stratigraphy is the same as the other profiles in section 28 where there is silty clay (16 feet thick),at the base followed by silt (12 feet thick) and a sand lens (6 feet thick) which did not appear elsewhere in the section. Above the sand lens is 34 feet of interbedded silt and sand and 16 feet of red brown till which formed the bluff top. The slope was again in two sections, the lower part being slump debris at a low angle (200), where as the upper slope holds a steeper slope (40*). A flowing spring was located in the medium sand above the more impermeable silt. The more stable looking slope at profile 4 was 100% vegetated and had a more even slope with no breaks and an inclination angle of 330, Despite the stable appearance of the profile a large opening scarp was forming at the bluff top. The beach at both of these profiles and to the end of the section is about 25 feet wide and consists of sand and pebbles. From profile 4 to profiles 5 and 6 the bluff height increases to 94 feet and the units within the bluff rise in relation to the lake level. The slopes of the bluff are completely vegetated (100%), with grass, bushes, and trees up to 15" in diameter. Between 28.52 and 28.9 a terrace formed by an old beach protects the toe of the bluff, making this stretch stable. At 28.9 the terrace is gone and the toe of the bluff is subject to erosion. Profiles 5 (28.94) and 6 (28.96) show a rapidly eroding area and a more stable wooded slope. The stratigraphy at profile 5 is the same as that which has been described throughout the section, with the exception that the rise in units has exposed more the lower silty clay (28 feet). Above this is the sequence of silt (14 feet), interbedded silt and sand (41 feet) and red brown till (12 feet) at the top. Seeps occur at the bottom of the sand and silt layer and are in part responsible for the slumping which occurs in the silt layer. The toe material of the bluff is slumped till and silts. 81 The adjacent more stable slope depicted in profile 6 shows only one. constant slope angle (28*), and is heavily wooded. The rapid toe erosion has triggered several small failures at periodic intervals on the bluff face (the largest of these is at the bluff top). The conditions described here, alternating slumped and wooded slopes, con- tinue to the end of the section. Section 21, T8N Section 21 begins with the conditions described at the end of section.28. The first stretch of the shore from 21.0 to 21.23 has a 25 foot beach of sand and pebbles and a bluff height that increases.from 98 feet to about 112 feet. The slope along the stretch has a rapidly eroding toe with a steep lower slope and more gentle upper slope. The failure is mostly of a translational slide type but a scarp due to rotational slumping was visible along most of the bluff top. The lower -1 of the slope is unvegetated while the upper is completely covered. 2 At 21.23 a small groin is responsible for a wide beach (50 feet) which protects the toe of the bluff north to 21.4. Along this region of beach the slope does not have a steep.lower half and the trees extend down to the beach. Profiles 1 (21.31) and 2 (21.33) are located at the northern end of the wider beach area. At this point the slope is less stable as shown in profile 1. Here the bluff height is 118 feet and the stratigraphy has graded to a slightly different composition or texture, than that which was reported in section 28. At the base of the bluff is a massive silty clay (17 feet thick) followed by a 21 foot layer of silt, silty clay, and clayey silt. Over these two units is a 50 foot thick layer of interbedded sand and silt and a 30 foot thick deposit of red brown till extending to the bluff top. The topography of the profile shows a steep toe of slumped material, above.which is an almost even slope of 30'. At the top ofthe bluff in the red till is a small scarp. There is a flowing seep at the base of the interbedded sand and silt which forms a small bog on 82 the slumped toe material. This sat .urated zone supports numerous horsetails. The rest of the slope is 70% vegetated with trees, grasses and shrubs. Profile 2 shows a stable slope that is 100% vegetated. This is a very interesting topographic profile in that it is the only convex slope found. The three breaks in slope form a bulging profile. North of these profiles to the point located at 21.43 the slope is inter- mittently stable and failing. The beach becomes very narrow and the bluff remains almost 120 feet high throughout this stretch. At the point (21.44) just above the water level there is a small exposure that was interpreted as bedrock. The resistant nature of the bedrock is reesponsible for the point. North of the point to about 21.52 a structure protects the toe and allows .a stable slope to be maintained. The vegetation extends to the 5 foot to 20 foot wide beach. Beyond the structure the scars of several slumps and slides are evident on the generally wooded slopes. When present the failures are usually due to rapid toe erosion-and then the sliding of the undercut upper units. Other than a slightly widening beach these conditions prevail to the beginning of the terrace at 21.8. Profile 3 at 21.76 is typical of the stretch. At profile 3 the bluff is 118 feet high and the beach is 10 feet wide. The stratigraphy from the base up is as follows: 5 feet of blue-gray, sandy, gravelly till; 9 feet of intermediate blue-gray silty till; 2 feet of brown- gray, clayey, till; 10 feet of clayey silt and silty clay interbedded; 34 feet of silt and sand interbedding; 19 feet of silt; and finally 39 feet of red brown till at the top. This stratigraphy varies from the more southern exposures in that the thick lacustrine clays found at the base of the last 5 exposures are here pinched to only 10 feet while the interbedded silts and sands have attained a thickness greater than that which is exposed to the south. The slope has a short steep toe (450) above which is a large even slope (35'). A small scarp marks the top of the bluff. Seep Is occur at the base of the upper silt layer 83 and at the. base of the interbedded silt and sand. The lower seep is very active and forms a small scarp from its sapping action. The entire slope is vegetated with shrubs and trees (locust and elm) up to 8" in diameter. Many broken concrete slabs add a minimal amount of toe protection. Profile 3 is at the end of the B part of reach 10. Reach 10C The third part of reach 10 is an area of Nipissing age terrace protecting a very stable wooded bluff. Section 21, T8N In section 21 from 21.8 to the northern end of the section an increasing wide terrace develops. (The maximum width of 320 feet is at the northern section line). The terrace is composed of the blue-gray sandy till just above or just below the water level and about 10 feet of sand, gravel and cobbles over- lying the till. This combination provides excellent erosion protection for the bluff and the terrace itselA for as erosion takes place, a wider beach is built. In addition to this natural protection most of the property owners have in- stalled a variety of seawalls, groins, revetments, and piers along the entire terrace. (Land use in this area is entirely residential.) The bluff above the terrace is considered very stable being removed from the eroding areas and completely vegetated. The slope angle in profile 4 was 26' and there was no evidence of scarps. Section 16- T8N Profile 4 of section 21 can be considered profile 1 of section 16 as it .was recorded along the dividing section line. The conditions described in this profile continue through the entire section with little variations. The land use is residential (Fox Point) so each property owner.has constructed some type of protective structure on his own land. This leads to a continuously protected shoreline consisting of revetments, seawalls, and groins. The - beach width varies with the type of structure used. 1-t reaches a maximum of 84 40 feet at 16.51 where a large groin is used, and is almost nonexistent where revetments and seawalls are present. The terrace width increases from 320 feet at 16.0 to almost 800 feet at 16.5 and then decreases to 480 at the end of the section. The stratigraphy is the same as that described earlier; blue-gray sandy till either just above or just below the water level with 8 or 10 feet of sand, gravel, and cobbles overlying the till. The bluff behind the terrace decreases in height from 111 feet at the southern section line to 90 feet at the northern section line. The slope for the whole section is completely vegetated and can be considered very stable. Section 1 1 T.SN. 0-21-1 The lake terrace described previously continues along first .35 miles of the section 10 shoreline. This first s-tretch of shore is completely residential and is well protected by many privately owned groins, revetments, and seawalls. Profile I along the 16/10 section line is characteristic of the first part of section 10. The terrace is 480 feet wide and, as expected, composed of sand, gravel, and cobbles with a blue-gray sandy till foundation. The bluff behind the terrace is 90 feet high and has a 250 slope for most of its length. (There is a short foot with an 180 slope.) Although this slope is completely vegetated, far removed from wave action, and without recorded seeps there were several minor slump scarps noted. Reach 10D At 10.35 the terrace disappears and the bluff is again subjected to the effects of wave action. The slope steepens slightly and the vegetative covering drops from 1007o to about 70%. There are no major failures in this stretch due to adequate toe protection in the form of a seawall. These conditions extend to 10.5 where a series of 5 groins build a wide beach. The wide sand beach area ends at 10.75 which is beyond the end of reach 11. The slope in the groin 85 area is 100% vegetated and at a lower angle than the area behind the seawall. This slope is considered stable. The land use from 10.35 to the end of reach.11 at 10.62 is.parkland (Doctors' Park). 86 'o 16.2 t -Y 12 2 10 Ir. 10 2 T7% ff:L7m*- 7 cjl 2 -7 3 7- 2A 10 10 A, 3 Public safety PUBLIC PERCEPTION: EROSION HAZARDS 2 Procerty Lt- I I Enwonment Re 0, C 10 1952 SHORE DAMAGE SURVEY -1 -S10.000 (1952) RECESSION RATESfo L-.',,.aopro..100 ym I (in feet/ yr.) 0 short - rern-approx.ioyrs. q SHORE HEIGHT (intensof feaO SHORE PROTECTION STRUCTURES - - - - - - - - - - - - - -HOUSES /MILE- Nort-ur ban - - - - - - -- - - -BOAT RAMPS T7N. 00 T. 8N. ct V e e L 7- 3 A 6(@ --Z 4d 2d I :1A 33/34 10 10 3 28 21 16 S A N D I LT COVLPED 0 R Generalized longitudinal section showing El UNACCESSIBI-r- bluff stratigraphy in Reach 10 . Numbers along base of diagram are geographic G.F? AV EL CLAY TILL (1 mile) sections. SAND AND CLAYEY' SILT, MlIXED C-;R,,"k',' EL 81':..TY CLAY SEDIMENTS University of Wisconsin--Extension 88 -Geological and Natural History Survey. 1-315 University Avenue, Madison, Wisconsin 53703 LOCATION AND MONUMENTATION SKETCHES Boring No. Date Drawn by 14 a@( BI ff, 4 - rh R 0 F-4 IL _'00 WA. snorerood V tv) 0 itw er S 1wif h iu 4 1 0 V A; C F:@ 1. E P1 AK. ,K rd k1 V@, ital C) 0 _7S tj fD %0 00 co* -j -1 (7% k.P., uli -P. rs w w N) " Fj M'0 CD @n (D t-n C) Ln Un C). tl-. Cl Ln C@ Ln C) Ln C) (D rr rnw rT 0 0 q ir in D3 F- C-r 0 ::s 0 0 0 (D pl;' o @c (D V\ (D F@ 00 00 -4 F@ H Fl F@ F. H Ul mCL t-ft U) fla LI) 03 co C) C) 0 @q t-n 00 W Ln 03 ce, ON 41. HF- %.0 I-D co 00 ON D. to 00 rl) Ln C-) H c @o Z4 F@ rt t@ r F- 0 C) 0 C) ch0 t-h 0 F- cn En In, @57 W e- 69 90 -d_ .91 d Sec.10 c c f b b .71 SP:'l .26 d 61 .51 0. 10 .41 C@ c Q .31 .21 b .02 .01 PA@CTo A- _jRj eoss the 0 n 1.00 C-,g;,.at to 1.25 COIVFID er than 1.23 Ilic VIV @ A-b Z" 'Jes (h @e h 0- 1 @L-p con t ence B-near bore Ole" strati rap C-no Strati visible visib, graph@, Conf e (low idence) T.7N.,R.22E.,Sec. 10 91 1. BLUFF a-relati-vely b-toe erosion c-severe toe d-relatively stable no where erosion with stable, no recent seawall translational recent failures failing, and slumping failures several deep above seated slow moving slump blocks on upper slope 2. TOE a-not b-till C-fill of d-not observed observed overlain by till because of sand and dense gravel in vegetation place and thick soil, probably till in place 3. BEACH a- +20 ft. b- -5 ft. c- +2o ft. d- -5 ft. sand seawall sand seawall and fallen trees e-5-20 ft. f- -5 ft. g- +20 ft. sand land seawall sand A cobbles T-7N.','R.22E.,Sec 10 120- 92 Prof He 100- ft. to 5 ft-depth so- l'- LLJ 60- LL 40- 20- 20 40 60 so 100 120 140 160 180 200 220 240 260 280 120- Prof He 100- ft. to5ft.depth so- l'- LLJ 60- LLJ LL 40- 20- 26 4'0 6'0 so 100 120 140 160 180 200 220 240 26Q 280 120- A Profile 1 100- ft,to 5.ft.depth SF=1.26 80- -50% vegetation at 150 ft. present, 100% befor, LLJ LLj 60- segment removed clear-cutting LL_ profile length -relatively stable 430 ft. 40-- y,b,-no real '20- beach B 20 40 60 80 100 120 140 190 1@0 200 220 240 260 280 F E E T w .9h. Ln ol -4 co 10 w 0 0 0 0 0 0 0 0 0 0 0 rn tj rm w 0 0 C6 94 T.7N.,R.22E.,Sec.3 C /SF=.46 0- 20 ft. d A B b SF=.69 b .51 c b 0- .51 10 ft SF=1.26.' C@ C .21 a a .11, a B A .01 0- GT-8 SF=.7 20 ft. CIO SAFETY FACTOR A-less than 1.00 Bm-1.00 to 1.25 C-greater than 1.25 CONFIDENCE LEVEL A-boreholes (high confidence) B-near boreholes stratigraphy visible C-no stratigraphy visible (low confidence) 95 T.7N.,R.22E.,Sec.3 1. BLUFF a-re.latively b-shallow stable, well translational protected slides, rapid toe erosion 2. TOE a-toe material b-slumped sandy c-till in not visible till, in place due to isolated vegetation places sand cover and gravel in place is VISIble 3. BEACH a-.+2o ft. b-5-20 ft. sand c- -5 ft. d-5-20 ft. sand beach sand and sand and gravel gravel 96 T-7N.,R.22E.,Se.c. 3 120 Prof He 1 6 /2 2/71 100- ft.to5ft.depth A 80- F_ LIJ -100% vegetated, LLJ 60- grass LL SF=.76 -relatively stable 40- 20- beach-f+ms, 80ft. wide,5 0 slope 20 40 60 80 100 120 140 160 180 200 220 240 260 280 120- Prof i I e 100- ft. to5ft.depth 80- LLJ 60- w 40- 20- 20 40 60 80 100 120 140 160 180 200 220 240 260 280 120- Prof i ie 100 f t. to 5 f t. dept h LLJ LLI 60- 40- 20- A Ad% xo% ')A n ')An !)Jqn A 120- 97 Profile4 100- -@i, S' f t. to 5 f t. depth @r Q, It e 80- -vegetation only on upper 1/3, 80% trees J 60- t'si up to 4 inches in diameter 40- -shallow slumps -translational SF=.46 movemeit si 20- ----------- m Qr seeps- C'SI __7 ------ - t, c t'si C beach-s,y,20ft. wide 49,slope 20 40 60 so 100 120 140 160 180 200 220 240 260 2W 120- A Prof i I e 3 T -?_ 100- 90% vegetation ft. to5ft-depth ---top of small slump scars 80- sample I C,sit- 0% vegetation -many small slump Li 60- scars at base of Li upper red till L ISF=.69 40- si ase of ma-11 slumps t,c B t s i -I; tL sample 2 20- S/fg beach-y, 10 ft.wide.100slope 20 40 60 80 100 120 140 160 180 200 220 240 260 280 120- Profile 2 100 ft.to 5 ft.depth 80- - 100% vegetation SF=1.2 - relatively stable jj 60- 40- b A 20- B=24.50 seawall 2ft. high z---,/ beach-s,y,p 42ft. wide slp I -_ - T I 20 40 60 80 100 120 140 160 11@0 200 220 240 260 280 F I E T SQ w -b- Ln O@ -4L 0 'U9 14 444b@ Lrl 86 99 T.8N.,R.22E.,Sec.33/34 h .91 h 9 9 .82 f .81 g f e .72 d .71 A C f e 0- e d 20 .51/ ft. d c 61 SF=.78 C --and .94 C .41 b .31 C c b- b SF=I.o 10 b .23 ft. .21 "I SF=.46 (D,- .11 34 A B 0- a a .01 20 a f t . 41 CO SAFETY FACTOR A-less than 1.00 B-1.00 to 1.25 C-greater than 1.25 CONFIDENCE LEVEL A-boreholes (high confidence) B-near boreholes stratigraphy visible C-no stratigraphy visible (low confidence) T.8N.,'R.22E.,Sec.33/34 100 1. BLUFF a-rapid toe b-relatively c-rapid toe d-large erosion, stable erosion, rotational slides protected slide-s on. slumping (shallow) by seawall upper slope on upper slope e-stable due f-slow g-rapid toe h-,slow to grading erosion, erosion erosion and seawall translational translational slides and slides several slump blocks. 2. TOE a-till in b-not visible c-in place d-slumped silt place due to silt and till vegetation covering e-not visible f-in place g-slumped silt and silt-and lacustrine till clays 3. BEACH a-5-20 ft. b- -5 ft. c-5-20 ft. d- +20 ft. send and seawall sand sand cobbles e- -5 ft. f- +20 ft. g- -5 ft. h-5-20 ft. sand sand revetment cobble T.8N.,R.22E.,Sec.33/34 1260 101 Profile3 t,/ SF=.78 ft. to 5 ft. dep!b 1007 SF=.94 so- t A-B 100% vegetation B-D 0% vegetation IJ 60- f-ms L 40- C'si'fs 20- si slump debris t' c t D 'SI I 20 40 60 80 100 120 140 160 180 260 220 240 260 280 -120- Prof i I e2 100- 110 ft. to 5 ft. depth 80- A A-B 100% vegetation SF=1.0 stable 60- 40- 20- B seawall beach-20 ft. wide,slope 10,7 0 at wate, 20 40 66 80 100 120 140 160 180 200 220 240 260 280 120 Profile 3 100- 115' ft.to 5 ft.depth A 80- t f-ms A-B 1.00% vegetation, B-D 0% vegetation Ljj 60- C'si'fs LL 40- si B SF=.46 t' c t'si 20- slump debris c bcach-pebbles,15 ft. wide,8 slop( I) ft -CAR -QAn F E E T w .0b. 0@' -3 co 10 rr, CA H. 1. 00 ca H. I-h fA 30 T T.8N.,R.22E.,Sec.28, 103 SF= 1.0 6 10 5 B C ft SF=.83 a k 20 50 ft. -28 C a SF=.83 h. I a DF=.79 b .41 9 A B .31 a SF=.86 SF=.93 e 0 d 20 .11 c .01 .02 10 SAFETY FACTOR A-less than 1.00 B-1.00 to 1.25 C-greater than 1.25 CONFIDENCE LEVEL A-boreholes (high confidence) B-near boreholes stratigraphy visible C-no stratigraphy visible (low confidence) Ab, 104 sec. 28 T.8N.,R.22E 11. BLUFF a-A series of b-fairly sta'ble c-in stable condition rotational slumps, condition due to although the presen- as waves erode toe, the seawall and ce of slumps, possibly bluff becomes un- sand build-up due to' the sand build- stable.Springs behind it which up at the toe from an pievalent in the protects the toe old beach deposit silt layer,standing of the bluff. which protects the toe. water on the bottom Scarp face Heavily vegetated. most slump -possible evident at the Scarp face evident at impermeable layer top of the bluff the top of the bluff. below which a lubri- cated plane is pro- duced for the faults to slump down. Vegetation is preva- lent throughout most of slope. Slop( angle seems to be approximately 400. Scarp face evident at the top of the bluff. d-same as a- above. 2. TOE a-slumped b-debris c-slumped d-slUmped till sand and till silt e-slumped f-slumped g-sand h-slumped silt till resulting silt from waves overtopping seawall i-sand, j-part of k-slumped 1-slumped possibly soil silt till an 'old profile beach deposit 3. BEACH a-greater than 25 ft.; approximately 10 ft. from the water's edge-pebbles and cobbles; to toe of bluff-medium sand. T 8 N.,R.22E. Sec.28 120 105 Prof ile 3 6/7-q/76. 100- 126ft. to 5 ft- depth. send slip face N.120 E. 80- C, t A-B 50% vegetation-trees. JJ 60- S/si gress,bushes L Toe- sl umped silt 40- -flowing seeps 20- si beach-ms,y, 39 ft. wide, 4' slope si,C B MS y 20 40 60 80 100 120 140 1160 180 200 220 240 260 280 120 Prof ile 2 100- 5 ft. to5ft.depth sand 80- A N.110 0 E. 3CL C, successsive escarpments A-B 40% vegeta t ; :)'n-ash, Ij 60- Eruiseedum,Typha -U si/s escarpments Angustifolia, honey suckle,locust 40- bi,ch,suga- maple flowing seeps sl@: 5(c Toe-slumped till 20- eouiseedum and typha angustifol-ia si,c I B beach-m-fs,y, 27 ft.wide. 70 slope 20 40 60 80 100 120 140 160 180 200 220 240 260 280 120- Profile I 100- 120 ft. to 5 f t.depth 80- A N-11.00E. escarpment Toe- slumped til.l. Ij C-t3o, .U 60- 40- si/s 1--each-ms,y, 25 ft- wi(ie, 20- flowing seep 7' slope si S-1 c 20 40 60 6a 11,60 IiAO 14C 40 1 'A- 200 7920- 20.0 260 280 r, r7 r: _r 120 106 T 8N.,R.22E. Sec..28 Profile 6 6/2Y/76 100- A 150 ft.to5ft.depth 3 ft. scarp at top of bluff sand N,900E 80- W SF=1.0 A-B 100% vegetation-trees, LLJ 60 grass,bushes U_ Small failures down bluff at periodic intervals 40- Toe-slumped till 20- B=28.5 B beach-s,,c, 20 ft.-wide, 40 sl 0pe T I -----I 20 40 60 80 100 120 140 160 180 200 220 240 260 280 120 Profile 5 100- A 150 ft. to5ft.depth sand N.qOOE. so- S/si A-B 20% vegetation- W W 60- Toe- U_ 40- SF=.83 20- si'C B beach-s,y, 0 40 60 80 100 120 140 160 180 200 220 240 260 280 120- Profilelil 100- 126 ft.to5ft.depth N.120 0 E 80- scarp face-partly vegetated A-B 100% vegetation-birch W up to 8", basswood, W 60- ash. LL B-C 100% vegetation-poplars , 40- B horsetails,willows Toe-slumped till SF=. beach-ms,y, 40 ft wide, 20 4 0slope C ms y A- F E E T w -Ph. ol -4 00 10 0 0 0 cn (n rT, ri) 4 In (n H. co 4 4 rt w rn co En rT CD rr Cl) cn LOT 108 T.8N.,R.22E.-,Sec.2l SF=I.l Q 104 7- L--. 103 -7:110 94 9@c, C e f -.92 0- -.91 -.83 10 -.82 f -.81 N, ED SF=.45 d A B 20- .61 50 21 f d r13) SF=.75 C d 'SF=.5 c -.31 b c -.22 B .21 b 0- b 20 ft. a T.SN.,R.22E. SAFETY FACTOR A-less than 1.00 B-1.00 to 1.25 C-greater than 1.25 CONFIDENCE LEVEL A-boreholes (high confidence) B-near boreholes stratigraphy visible. C-no stratigraphy visible (low confidence) T.M,R.@M,Sec.21 109 I.BLUFF a-rapid toe b-relatively c-slumping, id toe erosion with stable,no and Loe erosion.with translational recent erosion, translational slides above failures many seeps, slides above unstable e-relatively stable,no recent failures 2.TOE a-in place b-slide c-in place d-slide debris, silty clay debris,red silty clay, red till, till'silt not exposed silt and and sand sand e-intermittantly f-in place in place and paleo beach covered by a terrace thin veneer of slide and flow debris 3.BEACH a-5 to 20 ft. b-less than @c-less than d-less than sand 5 ft.,sand 20 ft., 5 ft., and cobbles sand cobbles and sand e-5 to 20 ft. f-less than sand 5 ft., sand and cobbles, revetment 110 T.8N.,R.22E.,Sec.21 -120- small scarp due to minor slump t Prof He 3 seeps 100- IE5 ft.to5ft-depth sand so- si _A-B 95% vegetation w -Foilure types: minor UJ 60- slump at top. Relatively LL sils SF=.45 stable in middle,minor slump and translational 40- movement at bottom. seeps -A-B-locust and elm up to si-c 8" in diameter. 20- C-1- concrete slabs beach-s,p, ;0 ft. wide si-t 0 7 slop,e 0, s-c-t,p 20 40 60 86 100 120 140 160 180 200 220 240 260 280 120- Prof He 2 612 -YI76 100- 150 f t. to 5 f t. deptt- sand 80- SF=.8 F- A-B 100% vegetation W 60 W LL 40- 20- B=380 s y 20 40 60 80 100 120 140 160 180 200 220 240 260 280 120- scarp face Profile I A t 150 ft.to 5 ft.depth 100- N.IIOoE so- F- S/si A-B 70% vegetation- W trees W 60- B-C 70% vegetation- LL horsetails 40- B seeps Toe- slump 0 beach-s,y, 7 slope si-c 20- s,si-c,c-si B=280 s y F E E T Ok -3 so 0- -0 0 rn cn 00 En .9lb 0 t .cn cn I . --- -- % rt 't En cn rD m 0 71) 0 cn I-IT T.8N.,R.22E.,Sec.16. 112 0 .101 C d -1.92 .91 -.82 0- -.81 10 f t c C a a b -.51 C 16 -.31 a C -.21 0- 10 .01 f SF=1.4 SAFETY FACTOR A-less than 1.00 B-1.00 to 1.25 C-greater than 1.25 CONFIDENCE LEVEL A-boreholes (high confidence) B-near boreholes stratigraphy visible C-no stratigraphy visible (low confidence) 113 T.8N.,R.22E.,Set.l6 1. BLUFF a-relat-4--ly stable, seve-ral &Iuri-tp s---:po noted. 2. TOE a-in place paleo lake terra ce, till and beach sand, gravel,cobbles 3. BEACH a-less than b-less than c-less than d-less than 5 ft. sand, 20 ft., 5 ft., 20 ft., revetment, sand sand,revet- sand seawall ment,seawall T.8N.,R.22E.,Sec.16 120 114 Prof i le 100- ft.to5ft.depth 80- W W 60- LL 40- .20- 20 40 60 so 100 120 140 160 180 200 220 240 260 280 120 Prof i le 2 100- A ft. to5ft-depW 80- SF=1.4 A-B 100% vegetation W 60- -trees up to 18 inches in W diameter U_ -stable slope 40- 460 ft. horizonte: 20 interruption B 0 terrace B 20 40 60 80 100 120 140 160 180 200 220 240 260 280 120- Profile i A :_--',,ft.to 5 ft.depth 100 80- SF=I.l A-B 100% vegetation W -trees up to 15 inches in LL, 60- diameter LL -stable slope 40- 290 J46 ft. horizontal 0 ft int =2 te rra ce B > interruption 20- R=29.50 s dential terrac sea wall AAA ovin )An Un 9M 115 T.8N.,R.22E.,Sec.l0 0 - SF= 1.39 b -C B C 0- 20 d ft. 10 b -.61 B C c .51 q -.32 - * 31 .21 C B a not present 4@ IQ? today 4z"" SAFETY FACTOR Am:@ less than 1.00 B- 1.00 to 1.25 C- greater than 1.25 CONFIDENCE LEVEL A- boreholes (high confidence), B- near boreholes stratigraphy@visible C- no stratigraphy visible (low confi6ence) 116 T.8N.,R.22E.,Sec.l0 1. BLUFF a-former take terrace b-No lake terrace, 100% c-Former take terrace protects a bluff with vegetation on a stable protects a bluff with approximately a 25 0 bluff, 30 0 slope. , approximately a 25 0, slope with 100% vege- Seawall to protect to e. slope with 100% vegeta- tation. No evidence no evidence of bluff tion. No evidence of of failure on the failure. failure on the bluff. bluff. 2-TOE a-toe material b-sand not visible due to shore structeres and vegeta- tion 3. BEACH a- -30 ft. in the b-no beach c- -15 ft. south grading to no medium grained sand beach in the north, composed of medium grained sand d- +25 ft. medium grained sand 117 T.8N.,R.22E.,Sec.10 120- Prof i le 100- f t. to 5 f tdep1h 80- W W 60- U- 40- 20- 20 40 60 so 100 120 140 160 180 200 220 240 260 280 120- Prof i le 100- ft. to5ft.deptt 80- F- W 60- W LL 40- 20- 20 4 66 80 100 120 140 160 180 200 220 240 260 280 120- Bluff condition: relatively stable lake ter-race protects bluff, in places evidence Prof i le I of former beach deposit which 100- protects the toe of the errace f t. to 5 f t. de pt h 0 Beach condition: orientation 120 1slope 7 1 -7 80- stable bluff, no evidence of failures, no seeps 410@ Lij 100% vegetation;' grass,trees,bushes W 60- terrace-100% vegetation; grass, LL trees,bushes,flowers,plants 40- SF=,! .39 /S 230 ft. interrupted 20- sample I beach-sand end A^ Af% ad% 4f%n Vi A IAA 200 220 240 260 280 r,;-, @ -1@, to %@ Av I i v .], I I 111111111111 3 ofolots 14102 493T