ML18059B019

Detailed Site Study,Berrien County,Mi, Final Rept

ML18059B019
Person / Time
Site:	Palisades
Issue date:	07/31/1993
From:	INTERNATIONAL JOINT COMMISSION - US & CANADA
To:	NRC
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ML18059B018	List: ML18059B019 ML18059B020
References
NUDOCS 9406070282
Download: ML18059B019 (64)

Text

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DETAILED SITE STUDY BERRIEN COUNTY, MICHIGAN U.S. NUCLEAR REGULATORY COMMISSION LiBRARY

..

FINAL REPORT .

July 1993.

'International Joint Commission Great* Lakes Levels Reference* Study Board

• Working Committee 2 Potential Damages Task Group

• ss~-os

• Page Number

-*-..-r

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TABLE OF CONTENTS EXEC'UTI'VE

SUMMARY

. . . . . . . . . . . .. . . . . . . . . . . . . . . . . * . . . . . . . . . . .. . . . iii 1.0 INm.ODUCfl:ON .*.................... *............ **....* . *. . . . . . 1 2.0 BERRIEN COUNTY DESCRIPTION ......... _.................... *. . . 3 2.1 l..a.nd Use ................ ~ ... ! * * * * * * * * * * * * * * * * * ** * * * * * * * * "* 3 2.2 Shoreline Classifications .................. -...... ~ . . . . . . . . . . . . 4 2.2.1 Shore Types ........* . . . . . . . . . . . *.. *. . . *. . . . . . *.. . . . . . . . . . . 8 2.2.2 Level of Protection . . . . ~ . . . . . . . . . . . . . . . . . . ~ . . . . . . . . . . . . 8 2.23 Subaqueous Nearshore Composition ................... *. . . . . 9 2.2.4 -. Erosion Sensitivity ..................* ......*.........* ...

• 9 2.3 Detailed Township Descriptions ............. : ...............-. . . 11

• 3.0 EROSION AND BLUFF RECESSION ................. *................ 31

. 3.1 MDNR Bluff Recession Rat~ Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

• 3.2

• Addition~ Previous Studies .. *.......... *. . . . . . . . . . . . . . . . . . . . . . . 32 3.3 ,Recession Rate Variability ....~ ......................... *....... _34 4.0 _HISTORIC DAMAGES ..... .- ............... : ... , *.. ._ . _. ...... : _. . 35 4.1 Historic Stage'.'Damage Relationships .......... ~ ............ ~ .... 35 *

• 4.2 Stage-Damage Curve Updates .......... ~ ......... -. ..... -....... : 35 4.3 Reach StUdy Investigations ...... ; ...... -. .. , ... ~ ............ -~ ~ . . . 36 .

5.0 DAMAGE POTENTIAL ESTIMATION .........-. . . . . . . . . . . . . . . . . . . . 37

• 5.1 Long-Term (50-Year) Recession Line Projections*** ... -...... _......... 37 5.2 Modified Long-Term Recession Line Projections . ~ ...... ; ........ *.:* 38 5.3 Flood Damage Potential ........:........................... *. . . 41 5.4 Long-Term Recession Potential Damages .............. ~ .......... 41

.5.5 Modified Long-Term Recession Potential Damages . -. *.............. 43 6.0 ANALYSIS OF POTENTIAL RIPARIAN DAMAGES . '. ....*..........". 45 6.1 Comparison of Potential Damages for 50% Range R~duction ...... -~ . . . 45 6.2 Comparison of Potential Benefits for 50% Range Reduction .......... 46.

• 7.0 LAND USE MANAGEMENT ALTERNATIVES ...... ~ ............... 49 7.1 l..a.nd Use Management Practices ... ~ ......................: ..... 49 7.2 Structural Shore Protection .................... ; .......... '. . . . 53 7.3 Non-Structural Shore Protection . ~ ............................. 59 8.0 BNDINGS ...................... ,*................... -..... ~ ....

• 61 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

• • i

Page Number.

LIST OF FIGURES Figure 1 - Berrien County, Michigan Shoreline Townships and Cities . . . . . . . . . . . . 5 Figure 2 - Hagar Township ....... ~ ...... ~ .... ~ .... *.. ,* . . . * . . . . . . . . . . . . 17

• 'i Figure 3 - Benton Township ...................*. ~ ....... *. . . . . . . . . . . . . . . 19 Figure 4 - St. Joseph Township ............................... *. . . . . . . . . 21 Figure S - Lincoln Township -. ................................... ~ . . . . . 23*

Figure 6. - Uke Township ...*.... *............. _....... -.... *..**. . . . . . . . . . . 25 Figure 7 -*Chikaming Township . . . .. ~ ._ ~ . . . . . . . . . . . . . . *. . . . . . . . . .. . . *. . . .' . . 27 Figure 8 - New Buffalo Township ...... ~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Figure 9 .; Typical Long-Term Recession Mapping ; .... : . .- . . . . . . . . . . . . . . . . . . . 39 Figure 10 - Aerial Photograph of St Joseph, Michigan (South) Shoreline ......... 57

• LIST OF. TABLES Table 1 - wd Use ................:............. _.....* ........ '* ~-- ~ ......... -. 4

• Table 2 - Land Use Categories* . ~ ............. *...........*...*. '. . . . . . . . . 7 Table 3 - Shore Types ............. **. *.... ,; . -. '. *~* ~ . ~ .... ~ ......... ; ... ~ .. 8 .

Table 4 - Level of Protection ;*.... ** ... * . * .- ....... *. *......* *. . . . . . . . . . . . . . . . 9 *

• • Table 5 *- Subaqueous* Nearshore Composition . ; .. *... '....... :.*............ : . 9 Table 6 - .Erosion Sensitivity .......... *.. : *. *........... .' .............. : _;. 11 Table 7 - Shoreline Classification Legend . . . . . . . . . . * . . . . . . . . . . . . . . ~ . * : . . . 15

'f.able S* - La~q Use /Long-Term (50-Year) Recession Line Mapping .' .......... 37

• Table 9 - Land Use/ Modified Long-Term Recession Line Mapping ........... 38 Table 10 - Long-Term (50-Year) Recession Potential Damages* ............. * .... 43 Table 11 - Modified Long-Term Recession Potential Damages ... *......... *. . . . . 44 Table 12 - Potential Benefits Due to Modified Recession Rates . -.. -.. : ........ *. ; . .44 **

Table 13 - Berrien County Statistics Compared with Reach 7006 . . . . . . . . . . . . . . -~ . 45

• Table 14 - Unit Costs for Shore Protection ~aterials - Uke-Michigan Shoreline ... *. 55 LIST OF APPENDICES

. APPENDIX A- HISTORIC RECESSION DATA ........................ ~. 65 APPENDIX B - PROJECTED 50-YEAR RECESSION DAMAGES . . . . . . . . . . . . 69 APPENDIX C - MODIFIED 50-YEAR RECESSION DAMAGES .. ** . . . . . . . . . . 73 ii

• .

DETAILED SITE STUDY BERRIEN COUNTY, MICHIGAN EXECUTIVE

SUMMARY

. .

The U.S. Army Corps of Engineers (USACE} has been assigned ~esponsibilities for*

. conducting detailed site studies at seven locations on the U.S. shoreline of the Oreat Lakes.

The site studies have been conducted in detail to determine the potential for damages caused by fluctuating Great Lakes water levels. One of the seven sites is Berrien County, Michigan, selected to focus on residential riparian. <;lamages caused by erosion.

Berrien County, Michigan is comprised of seven townships, located along the eastern shore of Lake Michigan and is the southern-most county in the state. It is bordered on the north by Van Buren County, Michigan, and on the south by LaPorte County, Indiana. The principal problem along the Berrien County shoreline is bluff recession which transfates into economic loss of property valµe in the coastal zone. Erosion of beaches and bluffs generally occurs throughout the county's shoreline, particularly during periods of high water.

Land use in Berrien Coµnt}r is primarlly residential riparian (71.2%),-with small percentages.

of commercial.(2.1%), public (2.7%), and agricultural (0.4%). The remaining 23.6% falls *

.into an .other/undeveloped category, being predominately sand dunes, woodlands, and

• outdoor recreatiOn facilities. Continued *land use development is eXpected ~ long as any undeveloped property remains available. *

• Berrien County's shore type is predominantly high till bltrlt with beach (55.9%}, foliowed by high till bluff ( > 15 meters) (31.0%). The majority of the shoreline has minor protection (69.3%) and the subaqueo_us nearshore. composition is 7R8% sand/gravel lag over clay.

Long-term ( > 30-year) mean recession rates in *Berrien County vary from recession:of 1.1 meters per year to a~cretion of 2.2 meters per year. Mean rec~ssion rates are greater than 0.3 meters per year for 70% of the shoreline, while very few kilometers eXperience accretion at all. *An erosion sensitivity model *was applied to. evaluate the impact of water level changes on shore types. Results of the erosion sensitivity analysis showed that as an effect.

of a 50% reduction in the range of water levels through control of Lakes Michigan-Huron

. outflows, approximately 60% of the shoreline would have a moderate (5-20%) reduction in bluff recession, 22% would have no reduction in current recession rates, .and 18% would be unaffected, since no recession currently exists in these areas.

. .

An inundation and erosion damage evaluation model was develpped during the International

.. Lake Erie Regulation Study in the late 1970's. It is based on shoreline reaches around the Great Lakes. Berrien County is part of Reach 7006 used for historic damage estimates.

The erosion and inundation stage-damage curves were updated for all reaches aiong the U.S. shoreline in 1991 to include damage information from the high water period 1985-1987.

• In 1992, t.Qe stage-damage curves for Reac;h 7006 were reevaluated in greater detail .

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To determine the adequacy of the results of the erosion-stage-damage curves, an alternate *..

methodology of determining potential damages was completed as part of this detailed site study. Historic recession data for Berrien County were used to determine a projected 50-year recession line. The recession data were then adjusted based upon erosion processes

• modeling of expected impacts from a 50% reduction in water level range to determine a "modified" long-term recession line projection.

The two recession lines were pfotted relative to the current bluff line to determine the number of structures that would be expected to be lost over the next 50 years* under the current water level r~ge, and consequently the number of structures that potentially could be saved under a 50% water level range reduction scenario. The number of structures were then multiplied by average township market values, and summed with estimates of the losses .

to developed and undeveloped lands, and losses incu:tred to roads. This was used to deteimine the potential damage and resultant benefits expected as a consequence of

• implementing this alternative water level regulation measure.

• A comparative analysis of this alternative approach and the stage-damage*model revealed that the erosion stage-damage model may. underestimate actual losses by a factor of 1.6 for this location. This inconsistency may be attributed to the inadequate reporting of losses to urtdeveloped properties in the past. This comparison also is based upon assumptions that may be contested. Another evaluation was conducted based on the potential benefits that would be eXJ>ected from a 50% reduction in water level range. The results of this analysis

. indicated that the historic stage-damage model may underestimate benefits derived by*the

• alternative methodology by a factor.of 2.7 for this location. Technical considerations cast doubt on the validity of this analysis, particularly if these results were appli~d in system-wide

• cost/benefit- analyses of alternative water level control measures. *

• A variety of land use management practices could be, or* in some cases have :been,

• undertaken in Berrien County to either reduce th~ potential for damage to existing shoreline

• property or limit the* damage potential due* to impt:()per future developm~nt. *Practices that

. should be considered include *remedial measures. for existing development (relocation, acquisition, irisrirance, *and/or structural anci non"'.structriral shore *protection} and

• . *preventative measures (such as setbacks, development controls, habitat preservation projects, and shoreline alteration regulations) to insure iha:t the damage potential is not exacerbated

.. in the future due to a* lack of foresight. * . * . - * . . .

..

• Private property owners in Berrien County have attempted shore protection using steel sheet

• piling, revetments, groins, sand traps, seawalls, and riprap. However, the protective structures are* often too scattered to present a corilmon barrier or are damaged and no longer serve their purpose. Further study is warranted to determine if large-scale structural shore protection measures could be cost-effective for Berrien County's shorelines~ and to determine the social,* enVironmental, and engineering oonsequences of this option.

Non:..structural shore protection, such as beach nouriShment and shoreline stabilization, are also used in Berrien County on approximately 5.5% of the shoreline. Beach nourishment

• programs appear to have mitigated erosion impacts immediately downdrift of the federal harbors at St. Joseph and New Buffalo.

IV

1.0 INTRODUCTION

DETAILED SITE STUDY BERRIEN COUNTY, MICHIGAN The Berrien County detailed site study was undertaken as part of* Phase lI of the International Joint Commission's (UC) Great Lakes -St. Lawrence River Levels Reference Study. Phase II continues the work.begun in Phase I to examine and report upon methods of alleviating the adverse consequences of fluctuating water levels. To guide this Phase, the UC established the Levels Reference Study Board, who in turn, established four Working Committees to carry out the specific tasks called for in the directive.

• Working Committee 2, land Use and Management, was primarily resporuiible for addressing environmental, physical, and social settings, economic impacts, and their interrelationships within the Great lakes - St. Lawrence River basin. Working Committee 2, in turn, established .five Task Groups to ac~omplish its missions.

• The Potential Damages Task Group was established to e~timate the incidence, frequency,

• and magnitude of historic and potential future damages~ The Task Group was also directed

• to evaluate potential damages that might . occur if certain alternative water level

• . management .measures were put in place .

The U.S. Army Corps of Engineers (USACE) was assigned responsibilities for conducting evaluations of potential inundation and erosion damages at seven locations on the U.S.

shoreline of the Great lakes. The Berrien County detailed site study, reported herein, was selected to focus on residential riparian erosion/recession damages, caused by fluctuating Great lakes water levels.

• The Berrien County detailed site study has been conducted to evaluate the relevance and accuracy of using* historic reported damages in estimating future potential damages over a

. 50-year project period, under both existing water level control conditions and alternative

• scenarios. The site studies were intended to address impacts in high spatial.detail and,. thus, to compare and contrast these results with those from system-wide economic impact.

evaluations. In addition, this site study includes information on land use management alternatives, including structural and non-structural shore protection options which could be considered to address the reoccurring beach erosion. and bluff recession problems characteristics of this Great Lakes shoreline .

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I.

• 2.0 BERRIEN COUN'IY DESCRIPTION Berrien County, Michigan is located along the eastern shore of Lake Michigan and is the southern-most county in the state. It is bordered on the north by Van Buren County, Michigar*. ruid on the south by LaPorte County, Indiana, with most Jocations being within an

• ~our and one-h~f to two-hour drive from Chicago, Illinois. It contains the shoreline communities of St. Joseph, Benton Harbor and New Buffalo; the Warren Dunes and Grand

• Mere State Parks; a Federal deep-draft harbor at St. Joseph; recreational boat facilities at New Buffalo and St. Joseph; and the Donald C. Cook Nuclear Plant. Figilre 1 is a map of the Berrien County shoreline, its townships, and cities.

The Berrien County shoreline is comprised of seven township. A listing of these townships, from north to south and their associated length of shoreline in kilometers (km) is as follows:

• Hagar, 11.5 km; Benton, 4.8 km;. St. Joseph, 9.0 km; Lincoln, 8.0 km; Lake, 10.6 km; Chikaming, 11.0 km; and New Buffalo, 12.5 km.

• The principal problem along the Berrien County shoreline is bluff recession which translates into economic loss of property value in the coastal zone. Erosion and recession generally occur throughout the county's shoreline particularly during periods of high water levels and storm events. The composition and orientation of the shoreline, the:bathymetry of the Lake Michigan nearshore zone, high water levels, and seasonal storms have all contributed in the past. to considerable beach erosion, attendant bluff recession and, as a consequence,

• significant economic losses to riparian property own~rs. * *,

2.1 Land Use For the Lev.els Reference Study, land use features along the.U.S. Great Lakes shorelines

• have been mapped from 1:24,000-scale aerial photos and encoded into a Geographic

• Information System (GIS) for storage, manipulation, and analysis. The photos for the state of Michigan. were collected in 1979. The land use classification scheme consists of 68 categories, including seven broad categories, these being: urban; agricultural; nonfores.ted; forested; water; wetlands;- and barren. The land use classes were then aggregated into five interest categories, these being: residential; commercial; public; agricultural; and undeveloped. Table 1 shows the land use, by length within the erosion zone, for Berrien County, Michigan, derived from manipulation and analysis of the data in the GIS databases.

Table 2 shows the 68 land use classes and their associated aggregate interest categories..

The most prevalent land use along the shoreline is residential riparian. The second most prevalent land use along the shoreline falls into the broad "other" or undeveloped category.

. The majority of this category along the Berrien County shoreline is sand dunes, woodlands, and outdoor recreation facilities. Shorelines originally classified as "beaches" have been included in Table 1 under either the residential or commercial categories depending on the

. land use immt:diately adjacent inland to the beach areas .

• 3

• Table 1 Land Use - Berrien County, MI Land Use Description Kilometers Miles Percent Residential 48.0 29.82 - 71.2 Commercial '1.4 0.87 2.1 Public 1.8 1.13 2.7

- Agricultural 0.3 0.18 0.4 Other 15.9' 9.93 23.6 In response to a questionnaire in May 1992 about land -use, the Southwestern Michigan Commission, a regional planning authority covering both Berrien and V~n Buren Counties, offered the* following thoughts pn futiire land use trends for their area of concern.

"Shoreland areas -continue to b~ developed, parti~larly for residential uses and to a lesser extent, marina and other _water-related commercial uses. Shoreland development is expected to continue at a moderate rate as long as undeveloped Qr underdeveloped areas

• are available. The restraint on dev_elopment induced by past periods of high lake levels and shoreline erosion has significantly abated."

• 2.2 - Shoreline Classifications

• Berrien County's shoreline. is orient~d along a northeast-southwest djrection and is exposed

• to direct wave attack from prevailing westerly winds. Intense storm5 associated with low

_barometric_pressure,.especially during periods of hlgh water levels, accelerate beach erosion _

- and ..CJ.ttendant bluff recession. The prevailing wind direction at St. Joseph if from the southwest and the net direction of longshore drift is from north to south (USACE, 1983).

. . . ~ . . ' . . .

-. The Lake .Michigan shoreline in Berrien County is- considerably diverse in geologic makeup.

-The Raphael and Kureth report (1988), entitled "Bluff Line Recession and Economic Loss.

in Coastal Berrien County, Michigan," describes the geology of the shoreline in good detail and should be consulted for further information. The geomorphic character of the Bemen

-_County shoreline is paraphrased from this report in the following sentences. From the Van Bu_ren Coun.ty line, southward through the Benton Harbor/St. Joseph area, to the vicinity of the Grand Mere Lakes; the geomorphology progresses from end moraine glacial deposits,

&1acial outwash deposits, and eolian or sand dune deposits. These deposits are exposed and in most cases form steep bluffs. Bluff recession is primarily due to slumping, creating a bluff line that is irregular rather than straight. The bluffs, and local dunal communities, are reasonably well vegetated with trees and scrub undergrowth.

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• BERRIEN COUNTY, MICHIGAN SHORELINE TOWNSHIPS

.AND CITIES N

t APPROX IHATE SCALE* I *Z50.800

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LOCATION MAP

• • Figure 1

• INTEREST CATEGORIES 1..ll!W!

Table 2

• LANQ USE CAIEGORIES a ' 11 Reaiden!ial a 111 Mulli-Femily: Medium to HiP Jlilo ...

a lll Muhi-Pemily: 1 - Jlilc a 113 Sillalc FlmiJr, Duplcz a 1IS Mcbile Home Patt c 12 Commertja!. Services. lnstiprtional c lll Primary/Ccnlnl BuliDcu Dillrict c lll SboppiD& Cmlcr/Mall c 124 Sccandaly/ Nciahbmliood BmiDcu DUtrid p 126 ln"indim*'

c 13 Industrial c 131 lndumial Patt 14 Tnnrportation eommunications. lJlilitiea p 141 Air TnmparWico c 142 Rail TnmporWiclll c 143 Wata Tl'llllpOrl&lioo p 144 llOld TnmporWiclll c 14.5 C-mjce1im*

"C 146 Ulilitia c 17 l!x!m!jve c l7J OpCD Pi1 c 172 tJDdu&rowid c 113 WcD c 179 Olbcr E1anclivc 19 0peg L!nd* O!her p 19 OUldcor Clillunl, Public .u-bly p 193 O\lldoor llc=aliaa

• c 194 Ccmc:ICrics A l AQBJCUL.TIJRAL A ll Cropland A ll On:lwd, Buab-Fruit, Villcyud, Omamaical Honiculnirc A 23 Ccmf'mcd Fccdiaa A 24 Pammait PUllmO A 29 Olbet A1ricu1ninl !.&di 0 .. 3 NONFORESTED 0 31 Hcrtaceo111 Opca1and 0 32 Shnlb 0 33 Pinc/Oak Opmina (Sav-11)

.0 4 FORESTED 0 41 DecidUOUJ W90dbnd 0 411 Not'lllml Hardwood 0 412 CCDlral Hardwood 0 413 AlpclllWlW BiRh A11oclalioa 0 414 1-llnd Hardwood

... o 42 CmifeT"OUJ w-fland

• o* 421 Piiie 0 422 Otbcr Upland Ccailcr

• 0 423 1-land Caailcr A 429 Maziaacd Olria1maJ Tree Pl&Zllalica

~

.51 Slrelm, Wa!nWay

.52 Late

.53 Reoetvoir

.54 Oru1 Utcs 0 6WEIL.. NDS 0 61 Woodtd WC'lbnds llii 0 611 Wooded 0 612 Shnlb, sCruh 0 61 N09woodnl WC'lbnds 0 621 Aqiwic Bed

• o 622 Emazmt 0 r623 Fllll '

0 624 Orcal 4Ua Couul Wdlands  :,:\ ::~ : :=> .. . . .

• 0 7 BARREN 0 7l Beach, River Bonk 0 73 s...d Dune 0 7.i Espostd Rocle 7

,..

2.2.1 Shore Types *=; ': ...... '! '*~ , .. * ;:: * .. . , *" ~* .. - . ., *

• ~ .

• ~ ' .

The shore classification scheme u~ed for the site studies was condu'cted on one kiiometer"' ' '

segments along the shoreline, referenr.ed to a starting point at the Mackinaw Bridge; running*

clockwise around Lake Michigan. TL~ shore .classification scheme was based on a three-**

tiered approach. The first tier is based strictly' on the geomorphic nature of the shoreline (shore type) which includes the following 17 categories: high till bluff; high till bluff with beach; low till bluff; low till bluff with beach; sandy/silty banks; clay banks;* relict sandy beach/dunes; coarse beaches; baymouth-barrier beach; bedrock/resistant; bedrock/non-resistant; low riverine plain; .open shore wetlands; semi-protected wetlands; composite

• shorelines; artificial; and unclassified. Table 3 shows

• the results of the shore type classification for B~rrien County derived from manipulation and analysis within the GIS.

Table 3

• Shore Types. :. B~nien County, Ml

.Shoreline Description

• Kilometers Miles 'Percent

,,

High ( > 15m) Till Bluff 7.0 . 4.38 ., 10.4 High Till Bluff with Beach Relict Sandy Beach / Dunes Baymouth-Barrier Beach 37.9 21.0.

1.9

"

23.53

'13~05 1.16 55.9 31.0

.2.8.

• 2.2.2 Level of Protection

. . - . .

• The second tier of information addresses the extent of structural shore protection that is in .*

place according *fo the following six .categopes;. highly protected; moderately protected; minor protection; no protection; non-structural; and unclassified. Table 4 shows the level of protection for Berrien County derived from manipub1tion and analysis of information in the GIS. The level of protection refers to extent of prptection only and not the quality of the protection. This is a very important point; no judgement is rendered on the engineering effectiveness of the various types of structural shore protection in place.

The only highly protected areas in Berrien County are at the Cook Nuclear Power facility, and the CSX Railroad/ Michigan Department of Transportation (MDOT) revetment/groin .

system south of St. Joseph:* The non-structural prot~ction areas refer to beach nourishment!

projects authorized under Section 111 at New Buffalo and St. Joseph .. ,; The beach **

nourishment program is in place to mitigate impacts of the navigation structures which

• interrupt alongshore transport of beach material.

8

• . Shoreline Description Table 4

• Level of Protection - Berrien County, *MI Kilometers Miles Percent Highly Protected 2.4 150 3.6 Moderately Protected 9~1 5.66 13.4 Minor Protection 46.9 29.18 69.3 No. Protection 5.6 3.46 8.2

'Non-stnictural Protection 3.7 2.32 .5.5 22.3 Subaqueous Nearshore Composition

• The third tier of the $horeline classification scheme addresses the subaqueous nearshore

• composition in the following six categories: clay; sand; sand/gravel lag over cI~y; bedrock/resistant; bedrock/non-resistant; and unclassified.** Table 5 shows the subaqueous nearshore composition for Berrien County derived from manipulation and *analysis of

• information contained in the GIS. *

• Table 5 * *

• Subaqueous Nearshore Composition - Berrien County, MI Shoreline .Description K.ifometers Miles Percent Sand "

.. 14.4 8.94 21.2 Sand/Gravel Lag Over Clay 53.4 33.17 78.8 2.2.4 Erosion Sensitivity

. '

The numerical evaluation of the impacts of water level changes on shore types was performed with a coastal engineering cross-shore computer model called the Advance Nearshore Profile Model (ANPM).

• In simple terms, this numerical model provides a comprehensive description of the 'coastal processes which influence the evolµtion of coastal morphology. It simulates coastal change under a number of different conditions and readily

• identifies the underlying reasons for a particular. form of beach profile response. An important feature of the model is that it is based on coastal proc~sses ranging from wave transformation (including shoaling, refraction, breaking, decay, and runup }, through 9

hydrodynamics (inciuding cross-shore and alongshore currents) to sediment transport and cohesive profile downcutting. Thus, the predictions and findings of the model can be linked **

directly to the physics of those processes, allowing for a fundamental understanding of the interrelationships between the processes and profile response. The beach profile version of the model is capable of considering the impact of seawalls ~d other impermeable strata such as clay, till, or rock on the response of the shoreline. The model is 2-dimensional, calculating beach profile changes in a horizontal (onshore-offshore) dimension as well as a vertical dimension describing depth. For a more detailed description of this model, refer to the Erosion Processes Evaluation Paper (Nairn, 1992), available from the Erosion Processes Task Group of Working Committee 2. -

The general application of the ANPM to cohesive and sandy shores required at ffrSt a detailed review of the available data and a description of the shoreline in relation to the classification scheme._ The numericitl modeling was then calibrated and verified for the local conditions. Then a series of hypothetical tests were run to investigate alternative water level management scenarios. - These conditions were input into the numerical model along with historic wave spectra to determine the erosion rates :that would _have occurred in the past

. under differing water level conditions. *

-In addition to the_ determinations of location and extent of certain shore types and the

- evaluations from the numerical model described above, it was necessary to identify the location and extent of shore types-that experience a change µi bluff recession as a result of water level change. _It was also necessary* to specify what types of shoreline these are (high bluff, sandy be-ach, etc.) and where they are located resulting in identificatiQn of areas where

• recession will be eliminated or reduced. Further investigations could then be carried out to determine the dollar value of benefit that would occur from an alternative water level management _measure.

a A two step process was then conducted. The first step was to define group of erosion

-_sensitivity categories, based on the results of the Erosion Processes Evaluation; .that described the response of the generic shoreline types to . a reduction in water level range.

The second* step was to develop an expert system for assigning each of the shore types into one of these sensitivity categories. Tµe erosion sensitivity categories are given below.

• Category lA - No Recession Category lB - No Reduction

• eategory 2 - Minimum or insignificant reduction in nonreversible recession Category 3 - Moderate reduction in nonreversible recession -

Category 4 - Significant reduction in nonreversible recessio~

Category 5 - Elimination of recession *

• Category 6 * - Reduction in active beach width Category 7 - Reduced recession, potentially- reversible Category. 8 * ~ Unclassifiable The expert system requires some knowledge-based decisions to assign the classification categories (shore type, level of protection, and subaqueous composition) to the categories *

.10

• defined above for erosion sensitivity. The shore type classifications originally contained 17 categories that were compressed into six loosely defined categories including cohesive,

-- beach, bedrock, low banks/wetlands; artificial, and unclassified. The level of protection classifications originally contained six categories that were split into protected and not protected. The subaqueous composition classjfications originally contained six categories that were grouped into three categories including unhindered downcutting, limited downcutting, and unclassified. A final key data element is the historical recession rate that has been deterinined for each shore type. Three key categories were identified including accretionary or stable, less than 0.3 meters per year and greater than 0.3 meters per year.

Other factors considered include the influence of surge and the nearshore slope. Table 6 shows the results of the erosion sensitivitY analysis applied to Berrien County.

Table 6

.

Erosion Sensitivity - Berrien County, MI Shoreline Description . Kilometers

• Miles Percent

• ,

No Recession 2.4 1.51 3.6 * . '

- -* - 21.7 No Reduction 14.7 9.14

,* ...

.~

Moderate (5-20%) 40.1 24.91 59.2 Elimination of Recession 7.9 4.90 11.6 Reduced Active Beach Width 2.7 1.65 .. 3~9 2.3 Detailed Township Descriptions The follo\ving describes the shoreline in Berrien County by reach, on a township basis, covering the shore tii>es, level of protection, subaqueous nearshore composition and erosion sensitivity classifications, as was describea at the county level in Section 2.2. Table 7 lists

• the legend information for the four classifications and is to be used when referring to the township figures that follow. A reach is defined here as a length of shoreline having the_

same characteristics (i.e. shore type, level of protection, and off-shore sediment type).

• Hagar Township is defined by two reaches (See Figure 2). The northern reach,

• approximately 4.8 km in length has a shore type classification of relict sandy beach/dunes; a shore protection classification_ of minor protection; a subaqueous nearshore composition of sand/gravel lag over clay; and an erosion sensitivity classification of no reduction in recession. .The southern reach, approximately 6.7 km in length has a shore type classification of high till bluff with beach; a shore protection classification of minor

• protection; a subaqueous nearshore composition of sand/gravel lag over clay; and an erosion sensitivity classification of moderate (5-20%) reduction in recessiOn.

11

Benton Township is defined by tWo reaches (See Figure 3). The northern reach, approximately 3.4 km in length has a shore type classification of high till bluff with beach; * *

• a shore protection classification of minor protection; a subaqueous nearshore composition of sand/gravel lag over.clay; and an erosion sensitivity classification of moderate (5-20%)

reduction in recession. The southern reach, approximately 1.4 km in length has a shore t; pe classification of relict sandyfbea~h dunes; a shore protection classification of no protection; a subaqueous nearshore composition of sand/gravel lag over clay; and an erosion sensitivity classification of reduction in active beach width.

St. Joseph Township is defined by four reaches (See Figure 4). The ~t reach, approximately 1.2 km in length has a shore type classification of relict sandy/beach dunes; a shore protection classification of no protection; a subaqueous nearshore composition of -

5and/gi'avel lag over clay; and an erosion sensitivity classification of reduction in active beach width. The second reach, approximately 2.1 km in length has a shore type classification of relict sandy/beach dunes; a shore protection classification of non-structural protection; a subaqueous nea.rShore composition of sand/gravel lag over clay; and an erosion .

sensitivity classification of no recession. This area should not encounter any bluff recession in the future since it is periodically renourished under Section 111 authorization.* The third reach, approximately 3.0 km in length has a *shore type classification* of high ( > 15 m) till

. bluff; a shore protection Classification of highly protected; a subaqueous

• nearshore composition of sand/gravel lag over clay; and an erosion sensitivity classification of moderate (5-20%) reduction in recession. This area contains the CSX RR/ MOOT system

.which is fairly heavily protected, but some losses are still probable due to land side seepage

• which could cause catastrophic bluff failures. The fourth reach, approximately 2. 7 km in length has a shore type classification of high ( > 15 m) till bluff; a shore protection classification of moderately protected; a subaqueous nearshore composition of sand/gravel lag over clay; and an erosion sensitivit)' of moderate ~5-20%) reduction in recession.

Lincoln Township is defined by five reaches (See Figure 5). The *first reach, approximately 1.3 km in length has a shore type classification of high ( > 15 m) till bluff; a shore protection classification of moderately protected; a subaqueous nearshore composition of sand/gravel

.. lag over clay; and an erosion sensitivity classification of moderate (5-20%) reduction in recession. The second r~ach, approximately *2.4 km in length has a shore type classification of high till bluff with beach; a shore protection classification

• of minor protection; a subaqueous nearshore composition of sand/gravel lag over clay; and an erosion sensitivity classification of moderate (5-20%) reduction in recession. The third reach, approximately 3.0 km. in length has a shore type classification of high till bluff with beach; a shore protection classification of minor protection; a subaqueous nearshore composition of sand/gravel lag over clay; and an erosion sensitivity classification of elimination of recession.

The fourth reach, approximately 1.0 km in length has a shore type classification of high till bluff with beach; a shore protection classification of minor protection; a subaqueous nearshore composition of sand/gravel lag over clay; and an erosion sensitivity classification of moderate (5-20%) reduction in recession. The fifth reach, approximately 0.3 km in length has a shore type classification of high till bluff with beach; a shore protection classification of minor protection; a subaqueous nearshore composition of sand/gravel lag over clay; and

• an erosion sensitivity classification of elimination of recession.

12

. '

• Lake Township is defined by four reaches (See Figure 6). The first reach, approximately 0.6 km in length h~ a shore type classification of high . till bluff with beach; a shore protection classifi~~~~n ~f minor protection; a subaqueous nearshore c_omposition of sand/gravel lag over clay; and an erosion sensitivity classification of elimination of recession.

.-'~e second reach, approximately 0.8 km in length has a shore type classification of relict sa:ndy teach/dunes; a shore protection classification of highly protected; a subaqueous nearshore composition of sand; and an erosion sensitivity classification of no recession. The third reach, approximately 8.7 kni. in length has a shore typ*e classification of relict sandy beach/ dunes; a shore protection classification of minor protection; a subaqueous nearshore composition of sand; and an erosion sensitivity classification of no reduction in recession.

The fourth reach, approximately 0.5 km in length bas a shore type classification of high till bluff with beach; a .shore protection classification of minor protection; a subaqueous nearsbore composition of sand/gravel lag over clay; and an erosion sensitivity classification of moderate (5-20%) reduction in recession.

• Chikaming Township

• is defined by* five reaches * (See Figure 7). The first reach, approximately 2.1 km in length has a shore type classification of high till bluff with beach; a shore protection cla5sification of ffiinor protection; a subaqueous nearshore composition of sand/gravel lag over clay; and an erosion sensitivity classification of moderate (5-20%)

reduction in recession. The second reach, approximately 2.0 km in length has a shore type classification of high till bluff with beach; a shore protection classification of *minor protection; a subaqueous nearshore composition of sand/gravel lag over clayj and an erosion

• sensitivity classification of elimination of recession. The third reach, approximately 2.9 kin in* length has a shore type classification of high till bluff with beach; a shore protection classification of minor protection; a subaqueous nearshore .composition of sand/ gravel lag over clay; and an erosion sensitivity classification of moderate (5-20%) reduction in recession. The fourth reach, approximately 1.2 km in length has a shore type classification of high till bluff with beach; a shore protection classification of moderately protected; a .

subaqueous nearshore composition of sand/gravel lag over clay; and an erosion sensitivity*

classification of moderate (5-20%) reduction in recession. The fifth reach, approximately -'4 2.8 km in length has a shore type of high_ till bluff with beach; a shore protection classification of minor protection; a nearshore composition of sand/gravel lag over clay; and an erosion sensitivity classification of moderate (5~20%) reduction in recession.

• _

• New Buffalo Township is defined by eight reaches (See Figure 8). The first reach, approximately 2.0 kni in length has a shore type classification of high till bluff with beach; a shore protection classification of minor protection; a subaqueous nearshore composition of sand/gravel lag over clay; and an erosion sensitivity classification of elimination of recession. The second reach, approximately 0.5 km in length has a.shore type classification of high till bluff with beacb; a shore protection classification of minor protection; a subaqueous nearshore composition of sand/gravel lag over clay; and an erosion sensitivity classification of moderate (5-20%) reduction in reoession. The third reach, approximately 2.0 km in length has a shore type classification of baymouth-barrier beach; a shore protection classificatioT\ of minor protection; a subaqueous nearshore composition of sand;

• and an erosion sensitivity classification of no reduction in recession. The fourth reach, approximately 0.4 km in length has a shore type classification of relict sandy beach/dunes; 13

a shore protection classification of no protection; a subaqueous nearshore composition of sand; and an erosion sensitivity classification of no reduction in recession. The fifth reach, approximately 1.6 km in length has a.shore type classification of relict sandy beach/dunes; a shore protection classification of non-structural protection; a subaqueous nearshore composition of sand; and an erosion sensitivity classification of no reduction in recession.

• This reach includes the beach nourishment area maintained under Section 111 authority at New Buffalo. The sixth reach, approximately 1.1 km in length has a shore type classification .. <

of high till bluff with beach; a shore protection classification of minor protection; a subaqueous nearshore composition of sand; and an erosion sensitivity. classification of moderate (5-20%) reduction in recession. The seventh reach, approximately 2.4 km in length has a shore type' classification of high till bluff with beach; a shore protection classification of no protection; a subaqueous nearshore Composition of sarid/gravel lag over '

' clay; and an erosion sensitivity classification of moderate (5-20%) reduction in recessi,on.

The eighth reach, approximately 2.5 km in length has* a shore type classification of high till bluff with beach; a shore protection classification of moderately protected; a subaqueous nearshore composition of sand/gravel lag over day'; and an erosion sensitivity classification of moderate (5-20%) reduction in recession. * ' *

"*.. '

'I'

' *.~

14

• COMPOSITE SHORELINE Table 7 Shoreline Classification Legend CLASSIFICATION LEGEND SHORE TYPE CHARACTERISTICS I I HIGH <>15M> TILL BLUFF I 2 HIGH TILL BLUFF WITH BEACH U 3 LOW <<15Mo> TILL BLUFF I 4 LOW TILL BLUFF WITH BEACH I 5 SANDY I SILTY BANKS I 6 CLAY BANKS I 7 RELICT SANDY BEACH. I DUNES

~ 8 COARSE BEACHES

'l BAYMOUTH-BARR.IER BEACH

~: 10 BEDROCK I RESISTANT>

I 11 BEDROCK !NON-RESISTANT>

I 12 LOW RIVERINE PLAIN

~ 13 OPEN SHORELINE WETLANDS

14 SEMI -PROTECTED WETLANDS I

f, 15 16 COMPOSITE SHORELINE UNCLASSIFIED EROSION SENSITIVITY I 17 ARTIFICIAL CHARACTERISITICS NO RECESS ION NO REDUCTION IN RECESSION

@ MINIMUM < 0-5% > REDUCTION IN -RECESS ION

@ MODERATE <5-20%> REDUCTION IN RECESSION SHORE PROTECTION 8 SIGNIFICANT <20%> REDUCTION IN RECESSION I HIGHLY PROTECTED 8 SIGNIFICANT <30%> REDUCTION IN RECESSION

• 2 MODERATELY PROTECTED SIGNIFICANT < 50% > REDUCTION IN RECESSION 3 MINOR PROTECTION 4 NO PROTECTION .@i ELIMINATION OF RECESSION 5 NON-STRUCTURAL PROTECTION © REDUCTION IN ACTIVE BEACH WIDTH 6 UNCLASSIFIED 0 *REDUCED RECESS ION .POTENT!ALL Y REVERSIBLE

.@ UNCLASSIFIABLE SUBAQUEOUS NEARSHORE COMPOSITION I CLAY 2 SANO 3 SANO I GRAVEL LAG OVER CLAY 4 BEDROCK <RESISTANT>

5 BEDROCK <NON-RESISTANT>

6 UNCLASSIFIED SHORE TYPE CHARAOER IS IT I CS

[if SHORE PROTECTION r- SUB-~OUEOUS 16 3 2 NEARSHORE COMPOSITION

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• 3.0 EROSION AND BLUFF RECESSION 3.1 MDNR Bluff Recession Rate Studies The Michigan ~epartment of Natural Resources (MDNR) determined bluff line recession rates in BemenCounty in 1978. ,Bluff recession rate studies were done on a township basis, as well as for specific locations in the county, including the Villages of Shoreham, Mjchiana, and Grand Beach, and the Cities of New Buffalo, St. Joseph, and Benton Harbor. The long-term recession rates were determined by photogrammetric methods using aerial photography' collected in 1938 and 1973. Special erosion hazard areas (SEHA), with average annual rates greater than 0.30 meters per year over the 35-year period were also noted.

The MDNR bluff recession data were the basis for the erosion sensitivity analyses discussed earlier and for the benefit/loss evaluations discussed later in this report. The MDNR data were referenced to the 1-kilometer segment corresponding to the shoreline lengths used elsewhere in the DC Levels Reference Study. The average recession rates used for economic evaluations are listed in tabular fo:rm in*. Appendix A

• Hagar Township in 1978 was mostly residential developm:ent with very few er~sion control

• structures present and a large amount of bluff vegetation. Erosio1;1 here is less, relative to

• most areas of southeastern La~e Michigan. Three SEHAs were noted. MDNR study area

• A, located at the northern tip of the. townsbip (km #s 783-784), has an average recession

. rate of 0.34 meters per year. Study area B, approximately 1 km in length, located just south

. of Lake Michigan Beach (km #s 786-787), has an average recession rate of 0.36 meters per year. Study area C, approximately 4 km in length, located at the southern end of the township (km #s 790-795), has an average recession rate of 0.43 meters *per year.

Bento_n Township in 1978 wa5 most.ly residential development with very few erosion control structures pres~nt and partially vegetated bluffs. Erosion. here has not been as severe as at other area5 of southern Lake Michigan. One SEHA was. noted.' MDNR study area A, approximately 3 km in length, located at the northern end of the township (km #s 795-798),

has an average recession rate of 0.43 meters pe~ year. .

St. Joseph Township data were not aWnable, but a study for the City of St. Joseph was available and is summarized here. The shore zone is dominated by two piers protecting the harbor at the entrance to the St. Joseph River, and extensive erosion control devices south of the community. One SEHA, with five subdivisions was noted. MDNR study areas A, Al, A2, A3 and A4 (km #s 801-802, 803-804, 804, 804-805, and 806, respectively) have average recession rates of 1.01, 0.67, 1.46, 0.73, and 0.98_ meters per year, respectively.

• Lincoln Township in 1978 had groins, seawalls, and.rock revetments built along several areas of the shoreline in an attempt to abate bluff recession. As a result, the recession rates

• cannot be considered as the entire result of natural erosion and accretion processes. The rates do reflect the past loss of upland material due to all erosion forces, man-induced and natural. Two SEHAs were noted. MDNR study area A, approximately 4 km in length, 31

• located at the northern end of the toWnship, was further subdivided into four subareas (km

1. s 808-810, 810, 810-811; and 811-813, respectively). These four areas have average recession rates of 0;88, 070, 1.13, and 0.49 meters per year. Study area B, approximately l km in length, located at the south end of the township (km #s 816-817), has an average

• recession rate of 058 meters per year. * ' .,

' ' '

Lake Township contaim Warren Dunes State Park which was not studied in the MDNR Stupy. Three SEHAs were noted elsewhere in Lake Township. MDNR study area ~ "'

approximately 15 km in length, located at the northern end of the toWllship (km. #s 817-818), has.an average recess~on rate of 0.58 meters per year. *study area Al, approximately 2 km i.n length, located south of and adjacent to area A (km #s 818-820), has an average recession rate o~ 0.79 meters per year. Study area B, approximately 0.5 km in length, located at the southern end of the township below Warren Dunes State Park (km# 827), .*

has an average recession rate of0.82 meters per year. *

. Chikaming Township had four main SEHAs noted; with three being further. subdivided.

• MPNR study areas ~ Al and. A2, approximately 1.5 km in total 1ength, located at the northern end of the township' (km #s 827-828, 828, and 828-829, respectively), have average recession rates of 0~82, 0.74, and 0.49 meters per year, respectively. Study ;µ-ea B,

. approximately 0.9 km* in length, located just south of area A2 (km #s 829-830), has an

• average recession rat~ of 0.70 meters per year. Study areas C, Cl and C2, approximately 4 *km in total length, located between Hazelhurst and Lakeview, MI (krii #s 831-832, 832-834, and 834-835, respectively), have average recession rates of 0.64, *i.10; and 0.58 meters per year.. Study areas D, Dl and 02, approximately 3 km iii total length, located at the

• southern end of the township (km #s 836, 836-837; and 837-838, respectively), have average recession rate.s of 0.43, 0.98, and 0.58 meters per year, respectively; '

' ' '

New Buffalo ToWnship *had four main SEHAs. rioted, With. one being further subdi~ded.

• MDNR study area A consisting of two sections, located on ei~ber side of the Village of Grind Beach (km #s 846-849), bas an average recession' rate of 0.61 meters per year. Study area B, located between the Village of Grand Beach and the city of New Buffalo (km#

844-845), has an average recession rate of 0.61 meters per year. Study areas .E and E2, located north of New Buffalo (km #s 841-842 and 840-841), have average* recession rates of 0.46 and 0.30 meters per year. Study area F, located at the northern end of the township

. * (~ #s 839-840), ~as an average recession rate of 0.31 meters per year.

3.2 Additional Previous Studies Several previous studies of bluff line erosion have been conducted and were summarized in Raphael and Kureth (1988). The reader is referred to that report for more in-depth

. information on these. previous studies.

Birkemeier (1980) detetmined bluff recession rates at five reaches from south of St. Joseph to Warren Dunes State Park. Sites 1 and 2, north of Grand Mere Lakes (km #s 808-810 and 810-812), are composed of glacial till with a sandy texture. Site 3 (near Grand Mere

• 32

• Lakes - km' #s 814-815), site 4 (near Bridgman - km #s 820-823) and Site 5 (at Warren Dunes State Park - km #s 824-826) represent unconsolidated sand foredunes~ Of the five reaches, Site 1 experienced the highest average rate of bluff recession between November, 1970 and November, 1974, a period of rising lake levels. At Site 1 the sandy bluff was unprotected, steep and unvegetated. The lowest bluff recession rates were measured at Sites 3 anc! 5, being undeveloped sand dunes. Recession rates at Site 1 averaged 4.60 meters per

• year, while the other sites averaged 4.20, 2.50, 4.50, and 3.43 meters per year, respectively.

Other work conducted by Buckler (1981) analyzed two sites in Berrien County. Site 1 was located north of Coloma Road in Hager Township (km #790) and Site 2 was located south of St. Joseph (approximately km# 805). Mean annual bluff line retreat at Site 1 and 2 between the 1830's and 1973 was 0.83 and 0.44 meters, respectively. Buckler also determined bluff line recession rates for 2.2 km of the Shoreham area (approximately km

1. s 805-807). He determined that the mean bluff line recession rate for this area was 0.91 meters per year between 1938 and 1977.

. A later study by Buckler and Winters (1983), determined bluff line recession rates for 56 sites on eastern Lake Michigan, with six sites located in Berrien County. Sites 1 and 2,

• between Shoreham and St. Joseph (km *#s 804-806) revealed average bluff line recession rates of 0.55 and 0.66 meters per year, respectively between 1829 and 1977. Sites 3, 4, 5 ~nd 6, north of Rocky Gap to Coloma Road (approximately km #s 798, 795, 793, and 790, respectively) recorded erosion rates of. 0.38, 1.31, 0.89, and 0.73 meters per year,

• respectively, from 1830 to 1977.

• Two eyewitness accourttS are also summarized.in Raphael and Kureth (1988). The first, a pune shoreline iri StevensVille (approximately km #813) experienced a total recession of about 6.4 meters between July; 1980 and November 1984, or approximately 1.5 meters per year. The second, a glacial .till shor~line in Shoreham (approximately km #807) experienced an average recession rate of about 3.20 meters per year between 1967 and 1973.. Another longtime Shoreham resident documented bluff 'line recession over a period of 57 years.

Within that period the bluff line retreated a total of 42.1 meters for an annual average rate of 0.74*meters per year. The greatest period ofloss at this site was between 1967 and 1973, during a period of high water levels, indicated an annual average recession rate of 3.20 meters per year. This demonstrates that bluff erosion can be intense during high water periods for these sites.

The Raphael and, Kure th study ( 1988) identified recession rates for three areas in Berrien County over the period 1980-1987. In the north area (Mizpah Park) (approximately km #s

• 790-798), over the period 1980-1987, the recession was measured for each 500-foot segment and the average total for* this section was 10.85 meters, for an annual average rate of 1.55 meters per year. In the central area (Shoreham) (approximately km #s 807-810), over the peliod 1980-1987, the recession was measured for each 500-foot segment and the average total retreat was 16.35 Dieters, for an annual average rate of 2.34 meters per year. In the south area (Grand Mere Lakes) (approximately km #s 811-815), over the period 1980-1985, the recession was again measured for each 500-foot segment averaging a total retreat of 8.70 meters, for an annual average rate of 1.74 meters per year for this section.

33

v

• In summary, Raphael and Kureth {1988) state that: "All sites reveal that mean annual bluff line recession rates in view of geological as well as historical times are very high." .,

"Recession rates are extremely variable over space and time. All investigations reveal that the area of greatest bluff recession occurs in the Central Area {Shoreham}." "From the view of time, bluff line recession rates follow a distinct pattern. Short }iistorical periods ... yield higher erosion rates whereas longer time frames of several decades reveal lower values."

"The temporal variation in the bluff line recession data suggests that higher recession rates are related to high water levels. The lower values, 2 to 3 ft./yr. [0.60 to 0.91 meters] for example, take into account longer time periods which included lower water and wider beaches, and little or no bluff line recession. In this way the high erosion rates during high water periods are mitigated."

3.3 Recession Rate Variability

' ' .

Bluff line recession is not a phenomena that is either spatially or temporally evenly distributed. Bluff retreat is highly affected by soil composition, bluff.slope and aspect, offshore wave orientation, offshore profile and sediment composition, presence/absence of beaches, inland drainage patterns, etc; Bluff retreat is generally never uniform from one

• point to the next, with differe~ces varying appreciably within distances. less than 1 kilometer in length .. The long-term rec~ssion rates in~luded in Appendix A to .this report are a composite of a number of bluff recession measurements made* over each 1-kilometer

.

• segment. The variances of these measurements have also been included in Appendix A Bluff recession rates are also highly affected by the time .Petjod chosen for the analysis. It is factual that during periods of high water levels, severe storms can cause Catastrophic bluff collapses, even within a 24-hour period. As such, the shorter the time-period, corresppnding

• • with high water levels and stonris, bluff recession rates would be higher. Over a longer period, however, these natural occurren~es will, be offset by perio.ds of low recession retreat

• • or none at all, .effectively reducing the* average recession rate* over time. This detailed.site study was conducted to evaluate the likely future recessi~n losses under existiiig lake

.regulation conditions

. in contrast_ to alternative scenarios

' . .

for a 50-year project period.

'

This study presupposes that if lake regulation does not charige,. average recession rates and sform occurrences over the next 50 years would be similar to those encountered over the last 35-years. To evaluate alternative lake reguiation scenarios, -the maximum ranges of water levels would be reduced, presumably resulting in a reduction of recession rates in the short- and long-term. * * *

• For Berrien County as a whole, the *me~ .50-year recession rate iS 20.4 meters, in comparison with a maximum of 39.2 meters and a minimum of 4.1 meters. Areas updrift of the maintained navigation harbors at St. *Joseph and New Buffalo have *long-term accretion rates. The range of 50-year bluff recession rates (discounting accretion zones},

from maximum to minimum value, is 35.~, meters. This overall variance is highly significant, in the long-term, since losses are highly site specific.

• 34

• 4.0 HISTORIC DAMAGES

• 4.1 Historic Stage-Damage Rela.tionships In the early 1970's; inundation and erosion relationships were developed by the International Great Lakes Levels Board and were documented in the report"Appendix C, Shore Property" to the main report on "Regulation of Great Lakes Water Levels" dated December 7, 1973.

In 1977, 1he Inte.rnational Lake Erie Regulation Study reviewed and updated this work to reflect damage data for the high water period of the early to mid-1970's. It was presented in the report "Appendix C, Coastal Zone" to the report by the International Lake Erie Regulation Study Board, dated July 1981.

The computer program Coastal Zone Evaluation (CZEVAL) was developed during the International Lake Erie Regulation Study and included routines to estimate erosion, inundation, and water intake pumping losses/costs as* functions of water levels. The CZEVAL model was formulated to be run on a reach basis, with the U.S. Great Lakes shoreline being broken into 37 reaches of similar geomorphology, ~lopes, and wave orientation. Berrien County is included in Reach 7006, running from Gary, IN to South Haven, MI. Berrien County comprises 52% of Reach 7006.

The CZEVAL inundation routine includes one inundation stage-damage crirve and historic

• monthly storm rises. Storm rises are the maximum differences between the highest instantaneous water level at a gage versus its montbly mean elevation. The inundation relationship for Reach 7006 is based upon water levels recorded at Calumet Harbor, IL The CZEVAL erosion routine is based upon ten monthly stage-damage curves, one for each month from March through December. The months of January and-February are not used s.

...

• since the nearshore area of the Great Lakes area is* generally ice covered, minimizing wave

.... ,

attack on the shore. The erosion routine is based upon a premise that damages are a function of waye energies and water level stage. This premise has been contested by most experts in the coastal processes arena.

• Both the inundation and erosion stage-damage curves were based upon a* comprehensive damage survey conducted during the 1973-76 period. A similar comprehensive damage survey was not conducted during the 1985-87 high water period.

4.2 Stage-Damage Cune Updates

• The most recent updates to the CZEVAL inundation and erosion curves were documented in the report *Great Lakes Shoreline, United States; Inundation and Erosion Stage-Damage Relationships" prepared by. Benjamin G. DeCooke, P.E., under contract to the USACE, in

• October, 1991. This update was* based upc;n partial inundation and erosion damages reported for the high water period of 1985-1987. All stage-damage curves were updated to

• 1987 constant dollar values for consistency. ,

35

During the 1985-1987 period, water levels at Calumet Harbor, IL, the closest long-term recording water level gage to Berrien County, were approximately 0.35 foot higher than .,

during the 1972-1975 period. In particular, the maximum monthly peak level of 582.0 feet (IGLD 1955) was exceeded 30% of the time in 1985-1987 and only 1% of the time in 1972;.

1975. This analysis showed that inundation damages for the 1985-1987 period for Reach 7006 would be slightly higher than that of the 1972-1975 period. The property along the shoreline of this reach is -highly priced* and most new construction would include the placement.ofprotective works (DeCooke, 1991). The inundation-stage damage relationship was updated and adjusted to reflect the 1985-1987 damage data and higher levels. This analysis, however, did not explicitly address new development since the mid-1970's.

The erosion stage-damage relationship for Reach 7006, updated. through the mid 1970's, produced erosion damages of approximately one million dollars 'more .than what was recorded for the period 1985-1987. The lesser damage were assumed to be attributed to the protection which had been placed. The relationships were therefore, adjusted downward to agree*with the damages reported for the 1985-87 period (DeCooke, 1991).

4.3 Reach Study Investigations A follow-up study was initiated in 1992 to evaluate the adequacy of the stage-damage

. relationships for four selected U.S. reaches, .including Reach 7006. This follow-up evaluation was conducted by Carl Argiroff, P.E., under contract to the USACE.* Additional

• field data were collected for Reach 7006 <11:1ring February through April 1992 .for use in this

. update. *

• During December 1985, a storm hit Berrien County causing bluff lines to move up to 2S meters inland almost overnight, toppling homes, erasing beaches arid causing the worst case of erosion in a decade. *Fourteen homes were destroyed and approximately 140 more were left within 10 meters of the eroded-bluffs (CA lhc, 1992).

The majority ofihe protective structures utilized along the sho~eline in Reach 7006 .were *

• installed to prevent erosion. Groins and revetments are _most often used.

• Groins are generally timber piles With wood wales on both sides and ,-iprap on the deep water end.

The toe of the bluff is often revetted to minimize undermining of the biuff. 166 permits were issued for Reach 7006 during 1984-1987, with. 137 including protection features. Of these, 114 were residential, 15 commercial/industrial and 8 for public use .. The estimated cost of installing these protective works was $3.2 million, with $1.9 million for residential,

$0.85 million for commercial/industrial and $0.45 million for public/institutional.

The C. A, Inc. Study generated updated inundation and erosion stage-damage curves for Reach 7006, indexed to 1992 dollar values. This -study generally concluded that the methodology developed in the 1981 Lake Erie Study and updated by 1985-1987 recorded damage~ appears to be the best .appro~ch for estimating likely benefits/losses from alternative water level control measures.

36

• 5.0 . DAMAGE POTENTIAL ESTIMATION 5.1 1.-0ng-Term (50-Year) Recession Line Projections The historical bluff line recession rates contained in Appendix A were used to project a "most-likely" recession line location SO years into the future. In order to do this, the current placement of the bluff line was interpreted from 1991 aerial photographs, at a scale of 1:6,000, and encoded into the GIS. The historic recession rate data were then used to plot the projected locatioris of recession SO-years ~nto the future for each mid-point of the 69

• kilometer segments in Berrien County. These points were subsequently fitted with a spline curve routine in the GIS to generate the projected SO-year recession line.

The GIS was then used to evaluate the anticipated .land losses over the next SO years by land use category, using overlays of the land use classes for each of the townships in Berrien County. Table 8 shows *the summary statistics for land. use areas inside the projected erosion hazard zone aggregated into the five interest Classes~ This analysis presupposes that future recession rates will be equal to those measured in the past.

• Table 8

.* Land Use/ Long-Te~(SO-Year) Recession Line Mapping ~*Be~en County: MI Township I Residential I Commerciai I Public I Agricult~e I .Other I Sub-Total I Benton 7.75 0.00 0.00 0.00 1.43 9.18

.Chikaming 27.21 0.00 0.00 0.00 233.93 261.14 Hagar 22.48 0.00 0.00 0.00 0.93 *23.41 Lake. 40.58 41.80 . 53.84 . 0.00 81.40 217.62 Lincoln 19.31 0.00 0.00 0.00 7.50* 26.81

. .>  ;

New Buffalo 28.70 0.00 4.10 0.00 3.89 36.69 St. Joseph 29.52 0.46. 0.40 2.15 3.54 36.07 I Total II 176.05 I 42.26 I 5834 I 2.15 I 332.62 I 610.92 I Note: Area unit of measure is hectares .

• 37

..

5.2 Modified Long-Term Recession Line Projections The projected long-term recession lines were then modified to include the numerical output

.derived from the ANPM erosion sensitivity process discussed in Section 22.4 earlier. These projections are b~!Sed upon the likely coastal responses to a 50% compression to the range of water levels on Lake Michigan. A 50% compression in Lakes Michigan water levels would be 0.98 meters versus the current 1.97 meter range. The following rules were applied for each one kilometer s~gment in the Berrien County coastal zone ..

Category lA:. No Existing Recession . * (Modification Factor = 0.00)

Category lB: No Reduction in Existing Recession (Modification Factor* = 1.00)

Category 3: Moderate Reduction in Recession (Modification Factor = 0.85) *~

Category -5: Total Elimination of Recession (Modification Factor = 0.00)

~tegory 6: Reduction. in Beach Width Only * (Modification Factor = 0.00)

Table 9 sho\Vs the change in coastal zone land use within the modified recession lin~. area.

Table 9.

4nd Use /Modified Long-Term Recession Line Mapping* Berrien County, MI Township Benton Chikaming I Residential

'

. 5.94 Z2;18

'*

I Commercial 0.00 0.00 I Public

..

0.00 0.00.

I Agriculture 0.00 .

0.00 I Other 1.02 2.21

~

I Sub-Total

.. 6.96 24.39 I **

Hagar 20.85 0.00 - 0.00 0.00 0.93 21.78

'Lake 15.53 0.00 0.00 0.98 26.50 43.07

.Lincoln* 9.58 0.00 0.00 0.00 4.37 11.16 New Buffalo 19.98 0.00 4.10. 0~00. 1.68 25.76

• St. Joseph 13.11 0.22 0.35 . 0.00 2.34 16.02

. Total I 107.17 I 0.22 I 4.45 I 0.98 I 40.63 I 153.45 I Note: Area unit of measure is hectares.

Figure 9 shows typical long-term recession mapping for Berrien County including the 1991 shoreline and b1uff line, the 50-year recession line, and the modified 50-year recession line, **

all overprinted on a 1991 aerial photograph for this section of the Berrien County shoreline .

38

~*

l.d IJC Level Reference Study -

Berrien County Detailed Site Study Typical Long-Term Recession Mopping

• -

-

-

-

1991 Shoreline Position 1991 Bluff Line Modified 50-Yeor Recession line 50-Yeor Averoi;ie Recession line Scale 1:6,000

• • Figure 9

• 5.3 Flood Damage Potential Approximately 95% of all potential damages computed from the CZEVAL stage-damage

• cuives for Reach 7006, including Berrien County, are attributed to erosion damages. The remaining 5% of the potential damages are ~ue to high water and storm-surge flooding.

Flood zones were mapped in the GIS for *Berrien County to the next mapped contour beyond the 100-year flood line. Shoreline land use data from 1979 aerial photos shows that only 0.8 km (0.52 miles), or 1.2% of the Berrien County shoreline length is within this flood zone. These areas occur mostly around river mouths in the county and are either adequately protected or are undeveloped at present.

. .

Based upon.this analysis and the,accuracy level for this type of study, it w~ concluded that no further analysis should be co~ducted on potential inundation damages f~r. Berrien .County*

under this detailed site study.

• 5.4 Long-Term Recession Po.tential Damages The value of a piece of property is highly influenced by its location. Lakefront property in

- Berrien Coul\ty has several features making it an attractive area in temis of market demand:

sandy beaches and bluffs offering beautiful vistas on the supply side; and, a.short drive from the city of Chicago*ort the demand side. The irifluence of location on lakefront property is

• so great that property values are appraised. b~ed on lineal feet of lake frontage, not area .

Berrien County is not a typical Great Lak~s *shoreline county in regards t~ property values.

The Berrien* County shoreline was divided into 69 segments, each being one* kilome~er in length. The exception is the end segments which are not one kilometer. in length, as the delineation does not correspond to county boundary lines. Based* on studies on historic recession rates, each segment has a mean 50-year recession rate computed, as listed in Appendix A Based on these data, a recession hazard zone was delineated as dis~ssed in Section 5~1. .. ..

The value of loss tO a property is clear. ~hen the ass.ociated development iS destroyed. The loss is tot~ and the value of the property is lost. The value of loss to currently undeveloped property or to the *undeveloped portion of property which has development outside the erosion hazard is not as clear. The two types of property were* valued differently._ The emphasis was placed on property with development (e.g., home) in the recession hazard zone. Throughout this report, the term "developed property" is applied only to such properties. There are 678 such properties in Berrien County within the 50-year recession

• hazard zone. The complexities of the recession rate analysis made it necessary to obtain property values prior to identification of the developed properties. All assessor's records were requested for Berrien County, with data actually obtained for New Buffalo Township (km #s 838-846) and Chikaming Township (km #s 826-838). These townships account for 143 and 161 of the developed properties, respectively, representing 45% of all developed

1 properties in this site study.

41

The New Buffalo Township data were fairly complete. Most of the developed property was

• valued according to its specific assessed value. The Chikaming Township data were less complete. Those properties were valued according to the average value of lakeshore developed properties on the same or adjacent plat map. For the rest of Berrien County, values for developed properties were assumed to range from $175,000 to $300,000.. These values are based on limited discussions with local experts. The values average to $223,325 for each of the developed properties. Property values in Berrien County tend to decline the further north they are located.

The value of expected damage to developed properties over 50 years was totaled *and

. divided by 50 to estimate the average annual loss. This method does not account for the time value of* money. More of the development on developed property lies at the* outer edge of the recession haZard zone than near the* existing bluff. A dollar lost today is worth a dollar today. A dollar lost 50 years from today is worth only 5 cents. today, when discounted 6%. .This method used to anm:ialize inay well overestimate eXPected annual

.damage.. . .

. ..

. Per Michigan state law, property was not reassessed during Jhe last two years. Beach front land values. may have increased sigruficantly during this. time and is. not. reflected .. in the assessor.records used'for these analyses. As such. this factotlnay.somewhat underestimate

• • ' eXPected damages. . . ** * * *. ,:

• : No attempt was m*ade in this detailed site study to predict future strticttiral or non-structur~

• erosion/recession comrols. Some devefoped property could be prote.cted at a cost less than the .expected loss. If protection is provided in both the Ba.Sis-of-Comparison (BOC - e~sting water level controls) and unde*r an alternative *scenario, benefits should be limited to 'the time value savings of delaying* expenditures .on protection. * * ***. . , . * :'

The value . of IOss to .property is *not *dear. when development . or *ihe

• potential. for

• development remairui.

• Th~re is a range of. possible*' losses to _undeveloped* properfy.

. Ownersr.ip may not change. The loss may be close fo zero ifundeveloped property is still

• devefopable .after 50. years. But this is not always the case. Undeveloped property also

• includes property with** development outside the recession -hazard* zone;

• Assuming an ..

average lot depth of 200 feet, 'this yields a. value of $1000 per foot of frontage, the valu.e of

. undevelbped land was assumed' to* be $5.00 per square ,foot. *This leads to .a total of

• $55,812,000 maximum potential loss of undeveloped property witbin the SO-year.recession hazard zone~ . .

Table 10 surrimarizes the results of the analysis for the 50-year recession hazard zone. The complete listing of potential damages, by kilometer segment, is* included in App~ndix B .

.--f'.*

42

• PROPERTY Table 10

• *Long*Term (50-Year)Recession Potential Damages . . Berrien County, MI POTENTIAL' AVERAGE ANNUAL TYPE DAMAGE (US $) DAMAGE (US $)

Developed Property "

Land 71,461,000 1,429,220

• .o ~

Structures 116,814,000 2,336,280 Undeveloped Lands 55,812,000 .. 1,116,240 .

Roads . 800,000 ... * .. 16,000

..

Totals Without Undeveloped 189,075,000 3,781,500 Lands  ;

With Undeveloped 244,887,000 4,887,740 Lands ..

5.5 *-Modified.Long-Term.Recession Potential Damages A similar economic impact asses.sment *was conducted on the areas identified in Table 9.*

(Section 5.2). These areas reflect a recession zone defined by a modified 50-year recession

• rate .. This line is generated with recession information from the. AN,:?M using __ a 50%

reduction in the. water levCI range. ThiS is the only altem~tive water control measure

....

capable of being analyzed through the methods outlined in 'this site study. This is due to the :ANPM results being limited to this scenario alone. .The 50% *reduction scenario was one of the most severe water level range compression alternative measure evalu~ted in *

• Phase Il of the uvels Reference Study. .

• Table-11* summarizes the results of the analysis of.the modified 50-year-~ecession hazard zone. The differences between these two analyses are the benefits which could potentially be derived from a 50% reduction in *water level range, which are reported iJi Table 12.

• 43

TYPE

. Table 11

--Modified Long-Term Recession Potential Damages - Berrien County, MI PROPERT'.&" POTENTIAL.

DAMAGE (US $)

• AVERAGE ANNUAL

• DAMAGE (US $)

• Developed Property Land-. 59,488,000 '1,189,760 .

. Structiires 101,662;000 2,033,240

. Undeveloped Lands 51,125,000 1,022,500

"

Roads 800,000 16,000

-. ...

Totals* - . -

'

Without Undeveloped 161,950,000 3,239,000 *..

.*.-. .

Lands I,

'

With Undeveloped * * . 213,075,000 ' 4,261,500

.-

• Lands ... * '

'*

PROPE:RTY, *.'

Table 12

• Potential Benefits Due to Modified Recession Rates: Berrie~ County, MI .**

POTENTIAL AVERAGE. ANNuAi.

• TYPE PAMAGE (US $)

• DAMAGE (US $)

..

, Developed Property . -

• , '[

Land-*:.* 11,973,000 239,460 ., ..

. ' ~. '

Structures 15,152,000 *, . . 303,040 Undeveloped Lands 4,687,000_ 93,740 Roads S1.' 0 0 Totals

• Without Undeveloped 27,125,000 . 542,500 Lands*

With Undeveloped 31,812,000 636,240 Lands 44

• 6.0 ANALYSIS OF POTENTIAL RIPARIAN DAMAGES 6.1 Comparison of Potential Damages for 50% Range Reduction Reach 7006 extends from the. Lake/Porter County line east of Gary, IN to the northern boundary of Van Buren County in Michigan. The entire shoreline length of this reach is*

approximately 129 km as follows: Van Buren County, MI - 21.1 km; Berrien County, MI -

615 km; La Porte County, IN - 10.8 km; and Porter County, IN~ 29.2 km. The counties

.in this reach are different in terms of their shoreline lengths, development, level of protection, and recession rates. *Table 13 shows the percentages for each county in Reach 7006, for these four categories. .

Table 13 Berrien County Statistics Compared with Reach 7006 J

Percent of Reach 7006 County Shoreline .* Developed Minor or No Recession Rates Length .. Shoreline Prote~ion > 1 foot/year

• Van Bureri

• Berrien

• La Porte 16.4

..

52.5 8.4 16.2 64.1 5.7

. 20.8 51.6 8.3

,.

' 12.5 65.3 5.5 Porter 22.7 13.9 .. 19.2. 16.r These summary statistics show that Berrien County, while having 52.5% of the shoreline length in Reach 7006 and 51.6% of the shoreline with minor or no protection; h?-S 64.1 %

• of the developed shoreline and 653% of the shoreline with recession rates greater than 1

• foot per year. These values illustrate that approximately 65% of all erosion damages that occur in Reach 7006, would likely occiir in Berrien County. *

• The BOC water levels, w~en input to the updated CZEVAL program, yielded average annual inundation damages for Reach 7007 of approximately $250,000 and average annual erosion. damages of approximately $4,680,000. Using the 65% proration, approximately

$3,042,000 of the Reach 7006 erosion stage-damage* average annual damages would be

• attributed to Berrien County alone. A one-for-one comparison of the average annual damages computed in Section 5.4 with the prorated value for the erosion stage-damage

• model output, indicates that the latter may underestimate damages by approximately 38%.

• In other \\iurds, the damages from the erosion stage-damage curves would have to be*

• multiplied by a factor of approximately 1.6 to adjust them to the ~alues determined in this site study report.

45

Sources of uncertainty can enter into these damage calculations. The variance in recession

• rates discussed in Section 3.3 could have a significant impact in the number of structures .

which are lost or saved, and therefore the resultant damage amounts. In addition, accurate values for property and structures, along with possible differences between assessed and

• market values, could have a significant positive or negative impact on *the damage calculations.

One significant explanation for this inconsistency may lie

• in the fact that losses of undeveloped properties have not been adequately reported in the past and, hence, were not expressly considered in the updates to the historic stage-damage relationships.

6.2 . Comparison of Potential Benefits for 50% Range Reduction A one-for-one comparison of average annual damages, such as detailed in Section 6.1, is one method of evaluating the adequacy of the CZEVAL erosion stage-damage model in system- .

wide benefit/ cost evaluations. J.t can be argued, With significant* merit, that the better

comparison would be to evaluate. differences in benefits derived by the dissimilar approaches.

In order to do this for this particular detailed site study, comparisons are necessary between the benefit5 derived from the reduction of erosion/bluff recession along the Berrien County shoreline based *upon a 50% compression m the current range of Lake Michigan water levels. The closest scenario evah~ated in *terms of benefit assessments to riparian conceniS

• generated through ihe CZEVAL stage-damage model would* be Plan 1.8 (SMHE0-50, Riparian Interest + /- 1 foot around the current mean). Plan 1.8 compresses the range of water Jevels on La~e Michigan 58%, whfoh is 8% more than the 50% compression in water levels used to generate th~ modifie-d long-term recession damage estimates. This difference

.is considered minor for a one-to-one average annual benefit assessment.

• Plan 1.8's averag~ annual erosion damage for Reach 7006 created from the CZEVAL stage-damage model is $4,320,000 in comparison to the .BOC average annual damage* of

$4,680,000, creating an average annual be11efit of $360,000 under this altemativ~ water level scenario. If the prior 65% proration is used to determine Berrien County's contribution to Reach 7006 damages, approximately . .

$235,000 of these annual benefits could be attributed to Berrien County. The resultant benefit in erosion damages, generated by a 50% reduction in water levels, shown in Table 12, is $636,240. This comparison shows that the benefits derived from the CZEVAL stage-damage model output for Berrien County could .be underestimated by approximately 63%. In other words, the benefits from the erosion stage-damage curves would have. to be multiplied by a factor of approximately 2.7 to adjust them

• to the values determined in this site study report.* * * ,'

The application of the aforementioned benefit comparison to system-wide cost/benefit analyses can _be debated due to technical considerations. These considerations include: 1) an inconsistent bases for the 50% reduction in water level range; aud, 2) the lack of relevance of this analysis to 3-lake regulation scenarios. Further discussion on these points

• follow. -

. 46

• '

• The erosion sensitivity classifications for the Berrien County shoreline were derived from analysis of the Erosion Processes Task Group. This analysis was based upon computer

• **

• simulation modeling employing a 50% reduction in the range of water levels around chart datum (176.0 meters/577.5 feet) for Lake Michigan. The CZEVAL benefit evaluation is based upon a SO% reduction in the range around the Iom:-term mean (176.25 meters/578.26 feet) for Lake Michigan. The 0.25 meters (0.76 feet) drop in reference elevations would enhance the level of benefits under the modified recession line. derivation, since water levels would not reach the toe-of-the bluff with the same frequency as under the BOC scenario.

This inconsistency does not adversely affect any system-wide erosion sensitivity analyses conducted for the overall study, but rather is a minor bias in favor of the efficiency of water level regulation in reducing shoreline erosion/bluff recession.

. .

The relevance of the benefit comparisons for Berrien County in respect to cost-benefit .

assessments for alternative Water level regulation scenarios such as Plan 1.18 (SEO-Extended) is an important consideration. For one thing, even if one assumes that the CZEVAL benefits underestimate actual benefits for this location for a 50% reduction in water level range by a factor of 2.7, it is not a logical extension to assume that any similar underestimation would occur for reduction in water level ranges for other scenarios that are*

much less than the 50% range compression evaluated. In particular, Plan 1.18 (SEO-Extended) provides for an approximate 22% compression in the range of water levels for Lakes Michigan-Huron. Benefits are likely non-linear due to the profile of the shoreline and the frequencies to which water levels reach the toe-of-the-bluff.

• . Another consideration is that the benefit comparisons for Berrien County may be irrelevant with regard to cost-benefit analyses for any other alternative water level regulation scenario in that the combined frequency of stillwater/stormwater occurrences do no~ provide for the anticipated reduction in highs; which are generally assumed to be the "trigger" for episodic bluff collapse. For the eastern shore of Lake Michigan, the Ludington, Michigan gage is a

• good example. Plan 1.18 (SEO-Extended) provides for a 0.33 meters (1.08 foot) drop in the . I maximum water level for monthly mean still water elevations. When one compares the 50-year maximum combined stillwater/stormwater elevation for Ludington, this reduction in*

maximum highs is only 0.26 meters (0.72-feet). It is art accepted fact that reduction in the maximum stillwater elevations does not translate into a "one-for-one" reduction in instantaneous water levels. Since bluff recession is a direct consequence of the frequencies of instantaneous water levels at the "toe-of-the-bluff," benefits derived froin a 50% reduction

• in stillwater elevations would not be expected for less severe water level compression scenarios .

• . 47

• 7.0 LAND USE MANAGEMENT ALTERNATIVES A variety oHand use ~anagement practices have been, or could be, undertaken in Berri~n County to reduce the potential for damage to existing shoreline property and limit potential damages that may occur due to ilLiJroper future. _development. In addition, several implementation mechanisms, or incentives, am be used to ~ncourage or discourage the use of land use management practices along the shoreline. The following paragraphs discuss the current extent; applicability, and effectiveness of several measures.

7.1 Land Use Management Practices Setbacks consist of regulations that require new shoreline developm~nt to take place landward *of a predetermined flood or erosion line. In Michigan, the setback distance has been determined as a minimum 30-year setback for areas with average long-term recession rates greater than 0.3 meters (J foot) per year. The landward receding edge of the bluff top*

is the ,baseline .from which the setback is measured.

• The determination of the 30-year setback limit in Michigan is uniform throughout the state, beiilg derived.under.the MDNR Bluff Recession Rate Studies described in detail in Section 3.1 of this report.

Cost information for ~etback developm~nt in Michigan is not readily available .. The MDNR has three to four staff memb.ers conducting- setback monitoring as part of th~ir *overall

• duties. They calculate recession rates and conduct permit reviews, with workloads varying from year to year. It is difficult to differ~ntiate tl;le amount of time that is directly attributed to setback monitoring (Ecologistics, *1992). * , * **

Since the 30-year setbacks were establ~shed in Michigan beginning in 1978, there have been only abouf 14 years of implementation.

• Due to this short time frame, no estimates of damages* avoided have been generated. During the last high water period, Michigan was

~ot in a position to quantify damage CO$ts.

. .

Under Michigan's _Shorelands Protection Program, the percentage of structures built at the minimum setback distance h~ increased since 1987. Statistics from the MDNR show that in times of lower water levels, a greater percentage of structure$: are. built at the minimum

• setback than during times of higher water. This implies that without the _regulatory prqgram enforcing setback requirements, many homes would be built closer to (or even within) the designated 30-year recessio~ hazard zone (MDNR, 1992).

Setbacks can be readily implemented in shoreline areas that ate currently undeveloped. The implementation of a setback is more problematic in areas of existing development, although they can be applied to redevelopment of lots. Some problems have been documented with consistent and aggressive implementation including variance permi~ting.

A setback is a distance referenced to an arbitrary time-period; in the case of Michigan, a

• 30-year period has been chosen perhaps to reflect the perceived iongevity of cottages along the shoreline. In fact, shoreline development is typically year-round along the southern 49

Lake Michigan shoreline, with new development typically being second- or first-homes. The

• longevity of these structures will likely vastly exceed the 30-year setback limitation placed

'on new construction along the shoreline. Erosion and bluff recession will continue, regardless of lake level controls or structural shore protection measures. Hence, even with 3(}.year setbacks in place for Berrien County, this measure will simply forestall economic losses into the future.

• Relocation of dwellings involves the movement and subsequent relocation 'of dwellings out of the flood and recession hazard zones. Relocations can be permanent or temporary. In 1985, Michigan enacted its Emergency Home Moving Program (EHMP), Public Act 108, which specified that relocating structures away from erosion hazards was the preferred alternative. The program was overseen by the MDNR who was authorized to provide grants or loans to property owners to relocate their. homes inland of a setback line. Homes that were within 10.7 meters (35 feet) of the bluff, in "imminent danger", were eligible, thereby not waiting until the damage had occurred. The program provided a 3% subsidy on 30-year loans of up to $25,000 per project, or a one time grant* of 50% of the project cost, up to

$3,500. During the initial phase; between August: 1986 and February 1987, the state received 273 applicatfons, of which 199 were found potentially eligible. *sixty-five relocation projects were certified as eligible, and sixty-two homeowners actually moved for a cost of approximately $267,000, with an average payment of $3,700. During the second phase in

, 1987, the state received 48 applications, of which 25 were found potentially eligible. Six.

relocation projects were certified ~ eligibl.e, and four homeowners actually' moved for a cost

• of approximately $24,000, with an average payment of $4,000 (Ecologistics, 1992). The U.S.

• Riparian Survey indicated that** out of 85 respondents* on Lake

• Michigan,: .4.4% bad participated in some form of moving of buildings'.. The number ofbomes relocated under the lv{ichiga~ program in Berrien County_, is unknown at the time of this report.

• Costs ofimplemeritation ofa home relocation progr~ such as that used in Michigan, can

• *be variable depending on the value of the structure* and .the extent of the relocation~ New

.*foundations and utility connections may have to be preparedj and* possibly additional land purchased. Some property owners may not find this a viable alternative if their lots are not

• deep enough to 'allow relocation to the minimum setback distance, and they cannot afford or do not want to relocate to another lot. Some homes, such as those with slab foundations,

. concrete block walls,* or extensive brick o~ stone. work are many times not considered movable (Ecologistics, 1992). * **

Home relocations, although costing initially more than the construction of shore protection, only occur once during the life of the home. The long term costs of maintaining a shore protection project would be ~voided, with an ultimate lower cost to the property owner over the long term. A University of Michigan SeaGrant research program deterinined that most property owners in the State of Michigan would spend more money on shore protection, over 20 years, than they spent purchasing their property, adjusted for inflation (Ecologistics,.

1992).

so

-* Flood elevation requirements ensure that new construction, or existing structures, in a flood hazard area would be. raised above a predefined level such as the 100-year flood line.

Michigan initiated a Home Elevation Program in 1985 and* received 196 application5, of which 150 were found eligible. Forty-two homes were rais.ed ~or a cost of $77,000. Result of the U.S. Riparian Survey indicated that out of 113 respondents on Lake Michigan, 5.8%

had participated in some form of building reinforcing while 82 respondents, or 4.2%, had participated in raising buildings (Ecologistics, 1992). Due to the low incidence of flood damages reported in the past for Berrien Cou~ty, it is assumed that no building reinforcement/raising occurred in this area during the high water period of 1985-87.

Land acquisition consists of purchasing property located in a hazard zone as a means of preventing future damages and losses to the property. After purcha.se, the property would be community or agency owned and be.converted to recreational purposes or allowed for different use th~t would significantly reduce or.eliminate future potential damag~s. Result of the U.S. Riparian Survey indkated that on Lake Michigan, 3.4% of the respondents had chosen land acquisition as a most preferred action that governments could take to alleviate the adverse consequences of fluctu~ting lake ievels (Ecologistics, 1992).

• Considering the magnitude of projected recession damages determined in this report

• * (upwards of $245 inillion over 50 years), and the fact that re~ession is a continuing process, it is dubious that government agencies woul~ have sufficient resources to implement this measure fully, even if it was socially or politicitlly feasible; throughout the Berrien County

• shoreline. However, the legitimacy of this management alternative should be ascertained for selected applications, where appropriate ..

Shoreline alteration require~ents consist of regulatuig public and private* construction of shore protection and navigation structures, including alteration of the nearshore by fill extraction or deposition.

• Proper technical advice and permits are required *before any alterations to the shoreline are' permitted. In Michigan, permits are required from the .,..

USACE and the MDNR. Duri:Qg the high water period of 1985-87, 137 permits were issued **If/>,

by the USACE for construction of erosion protection structures in Berrien County, with 114 of these being for residential use, 15 for commercial/industrial use, and 8 for public projects.

'These permits are consistently reviewed to det~rmine adverse impacts on neighboring*

properties, but do not typically address the engineering merits of the *projects being constructed. * *

• Habitat regulations include regulations to protect s~nsitive coastal and riparian habitat located' on private and public land.. Wetlands and other natural shoreline features such as beaches and dunes are protected from destruction under three state statutes: Goemaere-

Anderson Wetland Protection Act (203, PA 1979), Sand Dunes Protection and Management Act (222, PA 1976) and the Shorelands Protection and Management Act (245, PA 1970, as amended). A recent study by the Natural Features Inventory concluded that most. of the habitats undisturbed by human activity were already protected through acquisition or

• because they had been designated as conservation easements (Ecologistics, 1992) .

51

In Berrien County, 1979 land use stat~stics generated from the GIS indicated that ap_,::oximately 585 hectares of the 2,045_hectares (5~050 acres) within 305 meters or 1,000

• fo, of the current shoreline was in a natural or* undeveloped state. The majority of these nau.-al habitats were hardwood communities (57%), sensitive dune environments (21%),

and some wetlands (5%). Over the last 14 years, it is assumed that a portion of the natural *,

habitats along the Berrien County shoreline have also become developed. . At the time of .

this report, aJrrent estimates are unavailable ..

. Development controls for public Infrastructure would include the requirements for public agencies to locate public infrastrucnire outside. the hazard area and/or ensure facilities located in the hazard zone are done only out of necessity and that they are adequately located and protected. Public infrastructure in and of itself does not necessarily impact on shoreline development, but the subsequent development that it promote~- does (Ecologistic8, 1992)..This measure may not be adequately deployed throughout Berrien*County, since it works in contradiction to econo*mic development. plans*affecting local tax bases~

'

Loans can be used. to ~ncourage shoreJ.i:ne property o~ers to uftdertake certain shore protection or hazard reduction actions. Reduced interest tates or guaranteed repayment to the lender may make the above shoreline management actions more feasible. Michigan has an used loans as implementation mechaniSm, through its Emergency Home Moving Program (EHMP), Public Act 108, in 1985 to relocate structures outside of recession hazards zones The program provided a 3% subsidy on 30:year loans of. up to $25,000 p,er project, or a one *

• time grant of 50% of the project. cost, up to $3,500. .. . . , _*

.

Grants are similar to loans, with the exception that grants are outright transfers of money from one level o( government to another or to private property owners, with no requirement to ~epay the monies. An _overseeing agency *needs to be responsible for the distributioi of

.funding. The most significant barrier to the use of grants is availability constraints on state funding. Results of the U.S. Riparian Survey indicated that appto~ately 60% of riparians were in fay.or of governments .using grants and tax credits *to assist property owners. to construct shore protection~ Qver all, this action was considered the most preferred activity (Ecologistics, 1~92).

• lns~rance can encourage the proper ~e of property in the cm1stal zone and encourage municipalities to adopt floodplain management' programs. ResultS of the U.S. Riparian Survey indicated that approximately 28% of riparians were in favor of governments assisting property owners in paying flood insurance premiums, although only 2% ranked this as the most preferred option (Ecologist~~' 1992). The National Flood Insurance Program (NFIP),

administrated by the Federal Emergency Management Agency (FEMA); includes the Section 1362 Acquisition Program and the Upton-Jones amendment of 1987 pertaining to flood-related erosion damages. * **

• In 1987, Congress amended the Nationai Flood Insurance Act of 1968. Commonly referred to as the Upton~Jones Amendment, the 1987 amendment to the Act autho~ed .a "relocation/demolition program to provide for *the advance payment of insurance benefits *.

for structures subject to imminent danger of collapse or subsidence due to flood-related

• 52

• erosion. Flood insurance claims were paid after threatened structures were condemned, but prior to their collapse or sub~idence .. It was expected that, in return for advance payment of benefits, the property owners would meet . minimum setback . requirements for redevelopment or relocation. Relocated structures had to be moved landward at leas~ 30 times the average annual recession rate in order tcf be insured. Payment for demolition

• prior to collapse would be for 100% of the insured value of the structure plus an additional 10% to cover the cost of demolition. Payment for a relocation claim would be for the actual cost of relocation, up to 40% of the insured value o( the structure (Ecologistics, 1992).

In 1991, Congress passed the National Flood Mitigation.and Erosion Management Act (H.R.

1236) to increase compliance and enforcement of mandatory purchase requirements for flood insurance and to provide for inducements to improve .floodplain management requirements. One goal of C<>ngress in adopting thiS Act was *to encourage conimunities facing erosion problems to* ~irect future development to non-eroding areas, to reserve erosion-prone areas for open space, to coordinate planning with neighboring communities, and to adopt preventative measures for erosion hazard areas, including setbackS, shore protection works, and* relocation of structures. Measures also pronioted included the acquisition of frequently damaged properties for open space. As of 1990, many of these measu_res had not been implemented (Eco~ogistics, 1992);

Since its approval_ in. 1987, the use of the Upton-Jones provision of the National* Flood

• ,

Insurance Act has been minimal in Great Lakes coastal communities. On Lake Michigan,

.*

' from 1988 through 1992, $773,000 has been spent to either deq10lish or relocate structures in designated erosion ~hazards zones (Ecologistics, 1992). Specific information on the applicability of these insurance programs in Berrieri County have not been available at the time of this report. * *

,

• Tax incentives ca:n be applled *in a variety of ways to promote ot discourage *activities and .*.,

1;1ses along the shoreiine.  :

. *~'

• 7:1.. Structural Shore Protection Structural shore protection measures applied in Berrien County are primarily constructed to protect property from erosion damages. Common measures to prevent or lliinimize erosion include revetments, seawalls, breakwaters and groins. Measures such as dikes and levees, both temporary and-permanent, are used for'protection from inundation along the mouth of tributary streams flowing into Lake Michigan.

• Result of the U.S. Riparian Survey, for structural shore protection measures; indicated that

• out of 617 respondents on Lake Michigan, 31.7% had used fill or sand dumping; out of 248 respondents, 13.2% had constructed groins; out of 804 respondents, 4l.3% had reinforced the shore with stone, concrete or wood; and out of 323 respondents, 16.6% had constructed

• breakwaters (Ecologistics, 1992).

53

Private property owners in Berrien County have attempted shore protection using steel sheet piling and concrete revetments, groins, sand trap walls, seawalls, stone riprap, and temporary

• struc*:ures of assorted fill materials. However, the protective structures are often too scattu ed to present a common barrier or are damaged and no longer serve their purpose.

During the high water period of 1985-87, 137 permits were issued by the USACE for construction of erqsiori protection structures in Berrien County, with 114 of these being for

• residential use, 15 for commercial/industrial use, and 8 for public projects (CA Inc., 1992).

Revetments, generally consisting of large rocks, are placed on banks or bluffs to absorb the incoming wave energy. They are more ~ffective and have longer life expectancy when they

. are properly engineered, incorporating layers of rock of differing gradations with excavated foundations and/or filter fabric. Revetments have been one of the most common means of.

shore protection employed along the U.S. Great* Lakes shoreline. Its .popularity is due, .in large part, to adaptability to a variety of local . conditions and available materials.

Re\'etment costs are variable depending on the location of the. site, design and. mat~rials.

Seawalls/Bulkhea~s are commonly constructed to. protect loose fill, *sand or weB.k bedrock

. from wave attack.. They .are generally constructed of steel sheet piling, treated timber and .

concrete.. Seawalls can provide adequate shore protection if sited correctly and properly

.designed and maintained. Erosion problems can occur at the b.ase of the seawall, as

. bre~g waves reflect both upward and downward,. causing sc:oµring and µndercutting. -

Seawall/Bulkhead costs .are variable depe~ding on ~e. location ~)f the site, design and

• materials. *

• Brea~ters,- generally oonstructed qf .rubble. mound, *reinforced concre.te. or sheet.. piling caissons and timber and steel; provide protection to an area or shoreline on the leeward side of the structlire. .Offshore breakwaters are parallel to the shoreline, while shore-connected breakwaters-produce a harbor area with lllit#muin wave and surge action. Breakwaters are commonly used for harbor protection. Shore-connected breakwaters effectively ~ the

. water to the leeward side and interpose a littoral barrier until the impounding capacity is reached. Offshore breakwaters effectively. reduce. wave energy~. and sand tends to be deposited in the lee of the breakwater, accumulating beach material and thus increasing shore protection. Breakwater costs are often prohibitive for implementation by the private

. property owners.

.Groins are built *perpendicuiar to the shoreline t~* trap litt~ral drift or to retain an existing

.beach. Many* times they are constructed in groups, called groin fields; They are usually constructed of sheetpiles of treated timber, steel or aluminum with timber brace piles or

• mounds of rubble reinforcing the offshore end.

• Properly designed groins, effective in preventing erosion and increasing beach areas through accretion, must consider height, length, and spacing.. Groins* can potentially increase erosion rates on the downdrift of the groin or groin field. Groin costs are variable depending on the focation of the site, design and materials. ** * *

. 54

• An analysis of the level of protection for Berrien County shoreline reveals the following information. There are 19.1 km of the .total 67.8 km shoreline which are currently well protected. A further analysis of the remaining 48.7 km showed that 19.0 km would not likely be protected in the future, as these areas have recession rates less than 0.3 meters per year or development will not likely occur in the future. This leaves a total of approximately 29.7 km of the shoreline, with mean annual recession rates greater than 0.3*meters per year and insufficient extent (or quality) of current protection, that may need some type *of structural or non-structural shore protection *in the future.

Based on an assumption of a unit cost of $970.00 per lineal meter for protection derived in the W.F. Baird and Associates (1993) analyses, this 29.7 km length of shoreline would require $28.8 million of investment in shore protection over the next 50 years, for an average annual expenditure of $580,000. Table 14 lists some unit costs for shore protection materials for the Lak~ Michigan shqreline, used to determine the unit costs per lineal meter of j>rot~ction. *

• Table 14

.;

• Unit Costs for* Shore Protection Materials ...

,.

):i. Lake Michigan Shoreline

• I Material Quarried Stone Filter Fabric

.r Doll~s (U.S;). I *.Units 30.00 0.30

• .'

$/T

$/ft2 I

Excavation 4.00 $/yd3 Slope Preparation 1.50 $/yd2 '*.

• Earth Fill 11.00 ..

$/T Coarse *sand Fill 15.00 S/T

• Granular Fill 12.00 $/T Groins 16.00 $/ft2 Seawalls 15.00 $/ft2 Source: Baird & Associates, 1992 This analysis is supported by a differing procedure developed by the W.F. Baird and

• Associates (1993) to estimate system-wide potential avoided costs for shore protection. In the Baird analysis, it was estimated that $28.6 million would likely be expended in Berrien County over the next 50-years for structural shore protection.

55

Comparison of these costs with projected erosion damages for the same 50-year period indicate that implementation of structural shore protection measures at the most critically

• susceptible shorelines in Berrien County would have a benefit/ cost ratio of approximately

• 8.5 to .1. .These results 'ire preliminary and warrant further. investigation.

'

. ~

Implementation of structural shore protection comprehensively along the Berrien County shoreline is not a panacea. Revetments can impede access to beaches, reducing recreational opportunities; construction of groins, revetments, and seawalls can significantly disrupt

.human and natural environments; significant implementation of groins and revetments will starve beaches downdrift by robbing the natural sand sources (effectively moving the problem onto others); and, all of these measures can encourage (instead of discourage) further development in the recession hazard zone.

• The fong-term effectiveness of structural shore protection niea.Sures can also be questioned.

Costs in this study are base.d upon well-engineered and consistently maintained structural shore protection. .Most o( the shore protection clirrently in place can .riot meet these

• standards. *

'

, An example of a large-scale, well-engineered and maintained stru*ctural shore protection project is the CSX RR/ MJ)OT groin/revetment system immediately south of St. Joseph harbor. Figure 10 is an aerial photograph of a sectio~ of this.system. This system was built in the early 1970's to protect. an area with high beach. erosion and bluff recession.. "This .

system has been effective in controlling bluff recession during both *Of the high water periods of 1973-76 and 1985-87. Some bluff failure is evident on recent photographs behind. this

• system which appear to ~e caused by land drainage patterns.

• It is questionable whether *'ilie CSX RR I MDOT system may be able to maintain its effectiveness oyer its entire design life. The U.S. Geological Survey conducted a pilot study in 1991 using *side .scan sonar and ot!Jer sophisticated bathymetric sounding equipment to map coastal changes between St. Jos.eph and Michigan City. Preliminary results from this study indicated that the nearshore area immediately south of St. Joseph *harbor and immediately offshore of the CSX RR / MDOT system bas undergone as much as a 4 meter erosion of lake bed since 1964-65 (USGS, 1992).. This erosion has been speculated to be a transfer of wave energies from onshore erosion to vertical erosion of the lakebed. *In this particular case, the structural stabilit}' of the revetment may be affected, p'otentially causing a need for inore maintenance expenditures than anticipated over time. A detailed study of this particular area may be justified.

56

• Figure 10

• Aerial Photograph.of St. Joseph, Michigan (South) Shoreline *

., .

.:..-~

• 57

• 7.3

• Non-Structural Shore Protection Non-structural shore protection measures consist of a variety of methods to protect or stabilize the shoreline and bluffs, including beach_ nourishment and use of vegetation plantings~

Beach nourishment involves importing a suitable volume of unconsolidated material within the shore zone to maintain or develop beaches, to supply material for shore protection at the site, or by natural transport by wave actions and currents to other locations. Beach nourishment will not prevent a shoreline from eroding, it simply substitutes the eroding material (Ecologistics Limited, 1992).

• Large scale beach nourishment projects have

• . generally been undertaken as mitigative measures for harbor structures and not solely for shoreline management purposes. In Berrien County, beach nourishment projects are carried out by the USACE under .

the Section 111 program at St. Joseph and New Buffalo harbors.

.' - .

Beach nourishment at St. Joseph was initiated in 1976. An average annual quantity of 84,000 cubic meters is plac~d within a designated' feeder beach south of the harbor.

Material for beach nourishment is obtained from periodic maintenance dredging of the

.harbor and channel. Additional material, as needed, is obtained from inland sources. The time of placement is late spring or fall, respectively. The niean* gradation *~of the .

nourishment material ranges from about 0.2 niillimeters (mm) for the dredged material to

• about 1.0 mm for-the material obtained from inland sources. The gradation of the dredged material is relatively narrow, ranging from fine to medium sand. The material obtained from onland sources has a much broader range, from a few percent silt to small rock.

The results of the monitoring program at St. Joseph thus far indicate that, in general, the beach nourishment program has performed as intended. The beach nourishment program

• appears to be mitigating that portion of bluff recession.within the zone of adverse influence south of the harbor due to the presence of the Federal navigation structures. In particular, th~ shoreline along the reach of coastline where the beach nourishment material is* placed (the feeder beach) has been stabilized. There bas been no net recession of the shoreline along this reach from its position before the start of the beach nourishment program.

• It should be noted that this evaluation of the effectiveness of the beach nourishment does not consider any effects caused by the harbor structures that may have occurred during the period of time from their construction until the beginning of the nourishment program in 1976. The effectiveness of the use of coarse beach nourishment material at St. Joseph is currently being studied by the Coastal Engineering Research Center, USACE. This study will be completed in 1994.

Beach nourishment at New Buffalo was initiated in 1979. There is no required average annual quantity of beach nourishment at New Buffalo. However, since 1978, roughly 445,000 cubic meters of nourishment has been placed at New Buffalo for an average annual quantity of about 29, 700 cubic meters. The nourishment material is placed within a

• designated feeder beach south of the harbor. Material for beach nourishment is obtained from periodic maintenance dredging of the harbor and channel. . Additional material, as needed, is obtained from inland sources. The time of placement is late spring or fall, 59

• respectively. The mean grad'!tion of the nourishment material ranges from about 0.2 mm for the dredged material to about 1.0 mm for the material obtained from inland sources.

The gradation of the dredged material is relatively narrow, ranging from fine to medium sand. The material obtained from onland sources hB:S a much broader range, from a few percent silt to sniall- rock. . <

Unlike St. Joseph, the beach nourishment program was begUn soon after the construction of the navigation structures. As a result, the rate of placement of nourishment material has more closely kept pace with the amount of material blocked by the navigation structures. *

• ._The process of nearshore downcutting south of the harbor did not get an opportunity to

• develop before nourishment was begUn. The results of the monitoririg program at New Buffalo thus far indicate that, in general, the beach nourishment program bas performed as intended. It appears* to mitigate that portion of bluff recession within the zone of influence south of the harbor due to the presence* of the Federal navigation structures. As with St.

Joseph, the bluff and shoreline along the reach of coastline where the beach nourishment mat~rial is placed have been stabilized.

• The beach* nourishment placed *at St. Joseph and New Buffalo provides erosion protection

• benefits that extend so~thward, far beyond .the location where* it is placed and beyond the zone of influence. Although the extent of these *benefits have not been calculated, the

. nourishment' material helps maintain ihe beach and nearshore sediment supply as it is trailsp0rted southward under the influence of the' predominate alongshore current.

Shoreline stabilization using vegetation has been* applied extensively by Great Lakes *

• shoreline property owners experiencing slope failure and erosion problems. It is* relatively.

inexpensive and highly compatible with other land and water uses. Large-scale community based efforts for bio-stabilization of the Berrien County shoreline.have heretofore not been attempted. Indirect benefits could include improved visual quality and wildlife .habitat *.

• enhancement. The cost/benefits of biostabilization options for Berrien County have not

_ essentially been researched at the ti~e of this report.

• 60

• 8.0 FINDINGS

1. Results of this investigation revealed that Berrien Courity will experience approximately

$245 million in erosion damages over the next 50 years, or approximately $4.9 million

. annually, without further lake level controls.

2. Results of the erosion s.ensitivity analysis showed that as an effect of a 50% compression in the range of water levels on Lake Michigan, approximately 60% of the shoreline in Berrien County would have a moderate (5-20%) reduction in bluff recession, 22% would have no reduction in current recession rates, and '18% would continue to have no recession.

3. Further results of this study indicated that given a 50% compression of current Lake Michigan water levels, Berrien County will still experience approximately $213 million in erosion damages over the next 50 years, or approximately $4.3 million annually: This result is the* most significant finding of the detailed* site study, that being that controlling water levels on Lake Michigan within a range of Jess than 1 meter (versus the current near 2 meter range), erosion damages would only be reduc~d by 13% in Berrien Co~ty.

4. A comparative analysis with the results of the historic stage~damage' model used for system-wide benefit/ cost analysis revealed that the erosion damages generated by this model may underestimate actual. losses by a factor of 1.6 for this location.* This inconsistency may be due, in part, to a l~ck of adequate reporting of land IOsses for ,undeveloped properties

• in the past.: * *

,,

5. An additional evaluation of the adequacy of the erosion stage-damage model was .

conducted based on the potential benefits that would be expected from a 50% compression in water level range. *.The results of this analysis indicated that* the benefits derived from using the historic stage-damage model may underestimate benefits derived by the alternative methodology by a factor of 2.7 for this location. Technical considerations were noted that cast doubt on the validity of this analysis, however, particularly if these res\llts were applied to system-wide benefit/cost analyses of alternative water level control measures.

6. No conclusions could be drawn in this study on the effects of Plan 1.18 (SEO Extended) to erosion / bluff recession problems in Berrien County. Due to the complexity of the erosion processes, a linear interpolation of the coastal processes model output was not possible.

7. A variety of land use management practices could be, or in some cases have been, undertaken in Berrien County to either reduce the potential for damage to existing shoreline property or limit the damage potential due to improper future development. Practices that should be considered include ~emedial measures for existing development (relocation, acquisition, insurance, and/or structural and non-structural shore protection) and preventative measures (such as setbacks, development controls, habitat preservation projects, and shoreline alteration regulations) to insure* that the damage potential is not exacerbated

• in the future due to a lack of foresight.

61

8.. Private property owners in Berrien County have attempted shore protection using steel temporary structures o assorte 1 sheet piling and concrfete revedtmfile nts, gr~ins, sHand trap whalls, sea":alls, stone riprap, fand 1 matena s. owever, t e protective structures are o ten

• too *scattered to present a common barrier or are damaged and no longer serve their purpose.

9. There are approximately 30 km of shoreline which may likely undergo con5truction of

• structural shore protection, at a total cost of $28.8 million over the next 50 years, for an average annual expenditure of $580,000. Comparison of these costs with projected erosion

.damages indicate that shore pr9tection would have a b~nefit/ cost ratio of approximately 8.5 to 1. These results are preliminary and warrant further investigation. .

10. Implementation of structural shore protection comprehensively along the* Berrien County shoreline is n9t a panacea. Revetments, groinS, and seawalls can impede access to beaches, reducing recreational opportunities and ruin aesthetiCs; construction will disrupt human and natural environments; large-scale implementation will starve beaches downdrift; and, these measures can encourage. (instead of discourage) further development in the recession hazard zone. The long-term effectiveness of structural shore protection measures

. in Berrien County can also be questioned. .

' ' . t

. .

JO. Non-structural shore protection, such as beach nourishment and shoreline stabilization

• are also* us~d in Berrien County on approximately 5.5% of. the shoreljne~ The beach nourishment placed at St. Joseph and New Buffalo provides erosion protectic>n benefits that

• extend southward, far beyond the location where it is placed and beyond the zone of influence. Although .the extent of these benefits have not been calculated, the nourishment

' ;material helps maintain the beach and nearshor~ sediment supply as it fs* transported sout~ward under µie, influence of .the predominate alongshore current.

• .

62

• REFERENCES Baird, W.F., & Associates Coastal Engineers Limited, 1993. "Future Avoided Costs of Shore Protection - Final Report". Prepared for Working Committee 2, Potential Damages

• Task Group, UC Levels Reference Study.

Birkemeier, WA, 1981. "The Effect of Structures and Lake Level on Bluff and Shore

. Erosion in Berri~n County, Michigan 1970-74". Coastal Engineering Center, Miscellaneous Report 80-2, Fort Belvoir, VA

~uclder, W.R., 1981.. "Rates andJmplications of Bluff Recession Along the Lake Michigan

. Shorezone of Michigan and Wisconsin". PhD Dissertation. Department of Geography, Michigan State University, East Lansing, MI.

Buckler, W.R., and Winters, H.A, 1983. "Lake Michigan Bluff Recession". Annuals American Association of Geographers, 73(1):8~-110._

C.A., Inc., 1992. "Analysis and Report on Stage-Damage Relationships for Selected U.S. Shoreline Reaches". Prepared for U.S. Army Corps of Engineers, Detroit District.

DeCooke, Benjamin G., P.E., 1981. "Great Lakes Shoreline, United States Inundation and

• Erosion Stage Damage Relationships", Main Report and* Appendices A and B.

Prepared for U.S. Army Corps of Engineers, North Centr_al Division.

Ecologistics Limited, 1992. "Detailed Evaluation and Assessment of Shoreline Management Practices in the United States", prepared for the Great Lakes Comnµssion and U_.S.

• .

J\rmy Corps of Engineers, Detroit District.

• International Great Lakes Levels Board, 1973. "Regulation of Great Lakes Water Levels, Appendix C - Shore Property". Report to the International Joint Commission.

International Lake Erie Regulation Study Board, 1981. "Lake Erie Regulation Study,

• Appendix C - Coastal Zone". Report to the International Joint Commission.

Levels Reference Study Board, March 1993. "Final Phase Levels Reference Study Great Lakes - St. Lawrence River Basin, Final Report".

• Levels Reference Study Board,* March 1993. "Working Committee 2, Land Use and Management Final Report".

Levels Reference Study Board, March 1993. "Working Committee 2, Potential Damages Task Group Final Report".

• Levels Reference Study Board, March 1993. "Working Task Group Final Report".

. 63 Committe~ 2, Erosion Processes

Levels Reference Study Board, March 1993. "Working Committee 2, Land Use and

• Management Task Group Final Report".

• Michigan Department of Natural Resources, DiVision of Land Resource Programs,' 1978.

• "Bluff Recession Rate Study for Berrien County, Michigan."

Raphael, C.N. and Kureth, EJ.C., 1988. "Bluff Line Recession and Economic Loss in Coastal Berrien County, Michigan". Prepared for the Whirlpool Foundation, Benton Harbor; ~Michigan. In association with the Institute for ~mmunity and Regional

• Development, Eastern Michigan University.

U.S. Geological Survey, 1992: "Preliminruy ResultS of a Pilot Study Conducted Between St.

Joseph,. Michigan and Michigan. City, Indiana". USGS Open File Report 92-348.

Woods Hole, MA * . * *

(.

..

,; .

...

64

• APPENDIX A HISTORIC RECESSION DATA

• BERRIEN COUN1Y, MICHIGAN

• 65

• IJC REFERENCE STU>Y -* COASTAL PROCESSES TASICGROUP

<* ::'.'

lake Michigan alte study - Berrien County, Ml (29 Dec 1992)

Mean Mean 50yr Mean 50 yr Erosion ReceH Median Maxi- MlnlllUll

'ReceH Recess SensltlvyRate Recess Recess ReceH *Years Reach Shore Rate Rate ClaBB w/senslt Rate Rate Rate Varlanc I of of Data (ICllll) Class (ft/yr) <lllf50yr> (lll/50yr) (ft/yr) (ft/yr) (ft/yr) SaqilesRecord Type Confide Remarks

• 783 733 1.05 16.00 (11) 1 16.00 1.1 1.2 0.1 0.030 1.00 35.00 1.00 3.00 1938-73

• 184 733 0.44 6.71 (18) 1 6.71 0.1 1.2 -1.2 0.663 7.00 35.00 1.00 3.00 1938-73

• 785 733 -0.08 -1.22 ( 11) 1 -1.22 -o. 1 0.3 ' -0.2 0.052 5.00 35.00 . 1.00 3.00 1938-73

• 786 733 0.76 11 .58 (11) 1 11.58 0.1 1.1 .0.6 0.038 5.00 36.00 1.00 3.00 1938-74

• 787 733 0.96 14.63 (11) 1 14.63 1.0 1.4 0.4 0.085 10.00 36.00 1.00 3.00 1938-74 788 233 . 0.62 9.45 (3) 0.85 8.03 0.7 1.1 0.2 0.158 6.00 36.00 1.00 3.00. 1938-74 789 233 <1 14.33 (3) 0.85 12.18 no data available 790 233 0.54 8.23 (3) 0.85 1.00 0.1 0.1 0.2 0.053 5.00 36.00 1.00 3.00 1938-74 791 233 0.85 12.95 (3) 0.85 11.01 0.1 1.4 0.6 o. 137 4.00 36.00 1.00 3.00 1938-74 792 233 1.27 19.35 (3) 0.85 16.45 1.3 2.0 0.2 0.439 6.00 35.00 1.00 3.00 1938-73 793 233 2.23 33.99 (3) 0.85 28.89 2. 1 3.3 1.4 0.649 4.00 35.00 1.00 3.00 1938-73 794 233 1.28 19.51 -(3) 0.85 16.58 1.2 2. 1 0.1 0.337 5.00 35.00 1.00 3.00 1938-73 795 233 2.08 31.70 (3) 0.85 26.95 2.0 3.3 1.1 0.843 4.00 35.00 1.00 3.00 1938-73 796 233 1.00 15.24 (3) 0.85 12.95 0.1 1.8 o. 1 0.450 . 5.00 35.00 1.00 3.00- 1938-73 797 233 1.03 15.70 (3) 0.85 13.35 1.1 1.2 0.8 0.043 . 3.00 35.00 1.00 3.00 1938-73 .

798 233 o.n 10.97 (3) 0.85 9.32 0.6 1.3 0.2 o. 167 . 5.00 35.00 1.00 3.00 1938-73 199 743 -3.38 -51.51 (6) 0 . 0.00 -4. 1 1.0 -7.3 5.967 9.00 35.00 1.00 3.00 1938-73 800 743 -7. 17 -109.27 (6) 0 o.oo -6.9 -6.0 -8.9 1.020 7.00 35.00 1.00 . 3.00 1938-73 801 753 -5.43 -82.75 (6) 0 o.oo -5.3" 0.3 ~11.4 42.280 4.00 35.00 1.00 3.00 1938-73 St. Joseph Harbor

• 802 753 2.47 37.64 (11)1 37.64 3.3 4. 1 o. 1 2.840* 7.00 35.00 . 1.00 3.00 1938-73 O'I 803 123 2.50 38.10 (3) 0.85 32.39 2.5 3.0 2.0 0.250 3.00 35.00 1.00 3.00 1938-73

-..J 804 123 3.38 . 51.51 (3) 0.85 43.78 2.9 5.7 1.4 3.238 6.00 35.00 1.00 3.00 1938-73 805 123 2.~5 35.81 (3) 0.85 30.44 2.3 3.0 1.9 0.230 4.00 35.00 1.00 3.00 1938-73 806 123 3.73 56.85 (3) 0.85 48.32 3.5 5.2 2.7 1.276 4.00 35.00 1.00 3.00 1938-73 801 113 2.54 38.71 (1A) 0 0.00 -~-2 4.7 0.9 2.232 5.00 36.00 1.00 3.00 1938-74 808 113 3.75 57. 15 (1A) 0 0.00 4.0 4.7 2.3 1. 150 4.00 36.00 1.00 3.00 1938-74 809 113 1.43 21.79 (1A) 0 0~00 2.2 2.5 1.6 0.929 *3.00 38.00 1.00 'l.00 1938-76 810 113 2.55 38.86 (1A) 0 0.00 - 2.7 4.5 0.3 2.291 8.00 38.00 1.00 3.00 1938-76

• 811 233 3.38 51.51 (3) 0.85 43.78 3. 1 5.2 1.8 1.047 9.00 38.00. 1.00 3.00 1938-76

• 812 233 2.00 30.48 (3) 0.85 25.91 1.9 2.6 0.5 1.580 6.00 38.00 1.00 3.00 1938-76

• 813 0.05 0.76 (5) 0 0.00 0.3 1.1 -0.4 0.297 4.00 38.00 1.00 3.00 1938-76

• 814 23D 233 -0.01 -1.07 (5) 0 0.00 -0.2 0.4 -0.4 o. 115 6.00 38.00 1.00 3.00 1938-76

• 815 23 0~10 1.52 (5) 0 0.00 o.o 3.0 o.o 0.030 3.00 38.00 1.00 3.00 1938-76

• 816 233 1.97 30.02 (3) 0.85 25.52 2.2 3.2 0.5 0.899 6.00 38.00 1.00 3.00 1938-76

• 817 a1 0.68 10.36 (5) 0 -o.oo 1.2 1.9 0.9 0.675 5.00 38.00 1.00 3.00 1938-76 818 712 0.00 00.00 o.oo o.oo 3.5 3.7 2.0 0.643 4.00 38.00 1.00 3.00 1938-76 Cook Nuclear Plant 819 13?. 1.20 18.29 (18) 1 18.29 2. 1 2. 1 1.6 0.740 4.00 38.00 1.00 3.00 1938-76 820 732 3.28 49.99 (11) 1 49.99 2.6 4.7 1.0 1.644 4.00 26;00 1.00 3.00 1950~76 821 732 >1 51.82 (18) 1 51.82 no data available Varren Dl6les State Park 822 732 >1 51.82 (18) 1 51.82 no data aval table Varren Dl6les State Park 823 732 >1 51.82 (18) 1 51.82 no data available Varren 016les State Part 824 732 >1 51.82 (18) 1 51.82 no data available Varren Dl6le8 State Part 825 732 >1 51.82 (18) 1 51.82 no data available Varren Dl6les State Part 826 732 >1 5L82 (18) 1 51.82 no data aval table Varren Dl6les State Part

• 827 233 3.40 51.82 (3) 0.85 44.05 2.3 3.3 0.4 1.636 8.00 26.00 1.00 3.00 1950-76

• 828 233 2.52 38.40 (3) 0.85 32.64 2.6 3.9 1.4 0.644 9.00 26.00 1.00 3.00 1950-76

• 829 233 1.25 19.05 (3) 0.85 16. 19 1.2 - 2.8 o.o 1.041 12.00 26.00 1.00 3.00 1950-76

• 830 233 0.98 14.94 (5) 0 0.00 0.4 2.8 -0.8 2.334 9.00 26.00 1.00 3.00 1950-76

• 831 233 0.51 1.n (5) 0 o.oo 0.4 2.0 -0.6 0.691 9.00 26.00 1.00 3.00 1950-76

• 832 233 2.38 36.27 (3) 0.85 30.83 2.2 3.9 1.6 0.619 8.00 26.00 1.00 3.00 1950-76

• 833 233 3.38 51.51 (3) 0.85 43.78 3.4 3.9 2.8 o. 162 10.00 26~00 1.00 3.00 1950-76

• 834 233 3.26 49.68 (3) 0.85 42.23 3.8 4.7 1.6- 1.573 9.00 26.00 1.00 3.00 1950-76

• 835 233 1.67 25.45 (3) 0.85 21.63 1 .6 2.5 0.8 0.476 7.00 26.00 1.00 3.00 1950*76

.. 836 233 2.09 31 .85 (3) 0.85 27.07 2.0 3.8 o.4 1.641 9.00 26.00 1.00 3.00 '1950-76

• 837 233 2.62 39.93 (3) 0.85 33.94 3.0. 3.4 - 1.2 0.544 9.00 26.00 1.00 3.00 1950*76

• 1*

~

. *-

.,

"

IJC REFERENCE STUDY *.* COASTAL PROCESSES TASIC GROUP**

Laka Michigan aite atudy

• larrlen County, Ml

• '

Mean Mean 50yr MHn 50 yr Eraalon Recess Medlen M11xl- Mini-Receea ReceH SensftfvyR11t11 *Rece111. ... Rece111 Recess Teer*

Reech Shore Rate Reta ClllH 11/sensf t Rate Rate Rate Verlene I of of Date (ICll'IJ) Cla11 (ft/yr) (lll/50yr) (lll/50yr) (ft/yr) (ft/yr> (ft/yr) Saq>lesRecord TYJ'8 Confide Remarks:*

• 11311 1.79 27.28 cl> *o.85 "23.19 2.0 3.0 0.5 0.651 9.00 26.00 1.00 J;OO 1950*76

• 839 23b 23 0.81 12.34 (5) 0 o.oo . 0.9 1~6 0.2 0.261 8.00 30.00 1.00 3.00 1950*80

• 840 23 0.611 10.36 (5) 0 0.00 0.8 1.2 0.2 0.152 5.00 30.00 1.00 3.00. 1950*80 841 932 1.45 22.10 (18) 1 22.10 1.3 2~4 0.8 0.237 11.00 30.00 1.00 . ].00 1950*80 842 932 1.38 21.03 (18) 1 *21.03 1.J 2.2

• 1.2 0.082 11.00. 30.00 1.00. J.00 1950*80' 843 752 2.49 37.95 (18) 1 37.95 2.6 J.6 1.6 0;541 9.oo 26.00 1.00 ].00 1950*76 *ew Buffalo Harbor 844 75~ 1.* 38 21.03 (18) 1 21.03. 1.3 2.4 0.4 0.496 9*.00 26.00 1.00 3.00 *1950*76

• 845 2U 1.50 22.86 (3) 0.115 19.43 1.4 2.7. o.o 0.828 1Loo 26.QO 1.00 3.00 1950*76

~ 846 243 2.28 34.75 (3) 0.85 29.54 1.8 3.6 1.6. .0.366 10.00 26.00 1.00 ].00 1950*76

• 847 243 1.83 27.89 (3) 0.85 23.71 . 1.7 3.0 0.4 0.864 12.00 26.00 1.00 3.00 1950*76

• 8411 233 1.80 27.43 (3) 0.85 23.32 1.9 3.0 0.8 0.400* 12.00 26.00 1.00 3.00 1950*76

• 849 233 2.73 41.61 (J) 0.85 35.37 2.8 4.7' 0.6 1.988 12.00 26.00 1.00 J.00 1950*76

• 850 233 2.14 32.61 (3) 0.85 27.72 2.2 3.5. 0.8 0.901 11.00 26.00 1.00 3.00 1950*76

• 851 233 1.03 15.70 (3) 0.85 13.35. 1.2 1.6 o.o 0.272 7.00 26.00 1.00 3.00 1950*76 O'I Note: Mean rece111fon rate <1 f~t per year results ln.11 50 yr mean recession rate.of 14.33 meters per year based on a recession rate of 0.94 feet per year which 11 the 00 highest recession rate that will still round to le11 then 1 foot per year* *

• Data Type - 1.00 Cl Point location,' discrete value Confi~ence 3.00 Cl Mod~rately certain~ ~enerally accepted as, accurate .

. ,.

• APPENDIXB PROJECTED 50-YEAR RECESSION DAMAGES

• BERRIEN COUN1Y, MICHIGAN

• 69

' .

• Riech l50 149 148

1. 8'-

40 23 I

18 .

o...lcped S20 1,183 2:085 Al

~lll:ped I

Ut7 1

aeo 1,1115

I o.m.e- tar 8lrTlln ec.ny tar BOC Allmdl 2.500 LrdDlun9ge 1294.400 lt.IOB.tSS It .18'7:I06 1mpo.m.g.

St:l10:0S7 12.722.209 14.408,360 Undw1qft 40:eeD 118.t74 .

100:320 Undw.c.m.git

'203.SOO N"D610 SSOi*

147 Ul30 1.570 12.400.000 11.Ml:IOO 143:155 1711:275 1411 0 0 8,200 to to. 114.S>O lt,124,000 145 18 1,4t2 1,718 12.117.147 IU52.Mt 134,111 W70.588

.144 ao 8:000 IOO 14.5DD.OOO l1UDO.ooo tS.IOO Na.ax>

143 115 1.500 1,700 12.25),000 ll.7S>,OOO 111,llSS lt,O!!B.St7, 142 211 2.1100 eoo IUllO:C17S IU~Jl27 41,4CO '207.000 14t 17 UIOS 1.IV7 IU4t:700 lt,857,700 123.009 lltl5,D47 Mo 1S 2:413 7t7 12.714,4SO It .387:800 24,seB lt2t.MO Im 10 1.111 2.089 12.2154.200 IS.194,llOO 14.570 1422.15t ase 18 1,118 2.084 lt.129,300* 12:054.1117 186,518 1832,590 137 19 1,llOO 1.SOO 11,8(1),000 ts,040,000 170.D 1151,526 136 15 1.500 1,700 lt.5DD.OOO 12.400,000 177.Mt 1888.205 135 18 1,IOO 1,IOO lt.12D.OOO 12.11115,400 1suoo 1888.000 IS4 .1S 1,300 1.1100 1153,$93 ts,120,867 809:700 lt.548.!500 133 20 2.!500 700 12,!IOD,000 ss.m.ooo 111,SX> 1591,!500 132 10 157 U43 1157.t43 12.Ml.180 271.1100 11.sM:ooci 131 4 360 2.1140 . tseo.000 1998.933 72.SSIB 1381.888 l30 15 800 2.700 *l500.000 1832,!500 132,SX> tlllt ,!500 129 10 1.000 2.200 lt.000,000 11 :5411.030 1S7:11DO 11117,!500 128 S2 2.867* ass 12.111115,1187 ss.eoo.ooo 117.200 'ISSll.000 127 18 US3 1,1117 IUSS.333 lt.866.1167 St7:ll58 lt.!116.789 126 t 13 S,tt7 113.SSS 1118.1167 529,874. 12.Ml.S71 125 0 0 S.200 so so 1544.042 12.720.2t0 124 0 0 S.200 so so 1544.042 12.720.2t0 1123 1 100 s.too lt00.000 '200.000 1527.04t 12.1135.203 "*

122 t4 1,400 1.800 lt,400,000 12.I00,000 ll06.CJ24 lt.530.tt8 2.IOO.

• 1121 28 400 12.eoo.000 15.llCO.OOO 111.005 IS40.D26 120 11 1,100 2,too 11.1c:o.ooo 12.200.000 . S44.400 . 11:722.000: .

819 9 llOO uoo lll00.000 11.I00,000 1Sll.OOO SSll0.000 818 0 0 S.200 so so 0 so 817 3 SOD 2.llOO S300.000 Sll00.000 118.llCO 1493.000 8f6 I IOO 2.400 ll00.000 11,llQ0,000 *236.400 11 'tll2.000 115 *o 0 S.200 so so 18,0CO seo.ax>

814 0 0 S.200 so so 0 so 813 8 800 2.800 M00.000 l6001#J 8.500 132.llDO 812 21 . 2.000 1.200 12.1c:o.ooo 12.1(1),000 120,CXIO '600.000 811 16 t.600 1:600 11,ea:>.000 St ,llC0,000 270.400 St:SSZ.000 810 15 l500 2.700' '500.000 l500.000 344.250 St:721.250 809 .9 llOO 2,SOO '800.000 Sll00.000 114,450 . 1822.250 *:*

808 11 1.100 2.100 11.1c:o.ooo lt,1(1),000 893.750 S 1.968 .750 807 15 1.500 . 1,700 St ,!IOD,000 St.500.000 2tl5.SIOO St ,07'9:!500 806 13 uoo 1,100 11.soo.000 It ,SCX>.000 354.350 11.771,750 80l5 4 400 1,SOO 1.500 '400.000 '400.000 1152.750 1713.750 I04 4 400 1.SOO 1.500 '400.000 '400.000 2t9:700 It ,OSl8,l500 803 0 0 1.200 2.000 to so 150.ax> l750.000 I02 17 1,700 1.500 lt.700.000 lt.700.000 . 1815.236 S926.t8t 80t 0 0 S.200 so* so 0 so IOO 0 0 S.200 so so 0 so 799 0 0 a.200 to to 0 so 798 7 700 2.500 S700.000 1525.000 80.000 '450.000 797 15 l500 2.700 '500.000 '375.000 1S9:0715 18915.374 796 2 200 S,000 '200.000 1150.000 150,000 1750.000 795 4 400 uoo '400.000 IS00.000 2111.2D7 lt.4S6.037 794 12 1.200 2.000 lt,200,000 Sll00.000 121.018 164(),092 793 13 1.SOO 1.100 IUCX>:OOO 1975.000 211:880 11:059.400 792 8 IOO 2.IOO M00.000 '450.000 18$,059 18215.295 791 0 0 . S.200 to so 135.9158 16711.780 7llO 0 0 S.200 to so 111.400 * '432.000 789 2 200 4,000 '200.000 lt50.000 14t.04S l705.2t7 718 7 700 2.500 S700.000 1525.000 77,510 13117,549 787 14 1,400 1.800 lt,400,000 lt.050.000 86.S98 - 1431,188

• 786 8 IOO 2.800 Sll00.000 l450.000 18,780 14113,898 785 0 0 S.200 so so 0 so 714 9 llOO 2:SOO 14.!IOD.OOO SS.375,000 50.833 l253:t86 783 15 500 soo 0 l500.000 13715.000 15,748 1711.740 TOTAL 1178 84:943 142.757 1.000 . 173.tlt,SSt It 11.!itUtS 11:347:800 '56:738.00t 71

...

• !,

APPENDIXC MODIFIED SO-YEAR RECESSION DAMAGES

• BERRIEN COUNTY, MICHIGAN

• 73

.,

.: AMctl 850

1. S.

I

~

S20 Ale I I lion o.n.p. tor 8lrTilrl ~With l50'I!. Col11p1 u-.- *lafied aeo Alleda uoo t..ldDanwge 1294.400 mpDMwge I lion 11.910,057 Undevmq ft IM,581

~o.m.

1172.805 149 se 1,1&3 1.317 11,717,757 12.516,098 152,7¥ --* 1713.747 148 23 2,085 1,1115 11.167,806 l4,40U60 115.272 "'26.360 147 115 1,528 1.172 SUS>.000 U,Da7,DOO 130,CX!O "50,150 148 0 0 l.20D so so 110,CllD 11,5!50,400 145 18 1,412 1,7" 12.117,147 IUSU41 114,0DO 11570,DOO 144 30 a.ooo 20D 14,ICID,DOO 113,llDO,DOO 11.eao SU.ODO 143 115 1,!00 1,700 S2,2S),DOO U.niD,000 211,153 11,0!58.317 142 le 2.IQO IOO IUID.073 IU47#Z7 41,4(1) '207.000

• 141 17 1,503 1,897 lt,IMt,700 11,857,700 123,009 U15.1)47 840 0 0 I.ZOO SD so 0 so 139 0 0 l.20D so so 0 SD 1138 14 m 2.224 11.aae.1ae 11.717,396 189,1153 SMS,784 137 11 1,100 2.100 11,100,DOO 11.780.DOO 233,842 11.11u10 836 11 1,100 2.100 11,100,DOO . 11.7S>.OOO 118,!RS .1932.816 135 14 1,400 1,800 11,llD,000 11.1115.800 127,1515 sw.m 134 12 1,200 2,000 UI0.000 IUllD.800 277,100 l1.S815,l500 833 18 2.DOO 1.200 12,oa>,OOO 12.ess.zoo 172,3110 U81.IDO 132 10 1157 2,143 11157,143 '2.540,180 2311,llllO 11.114,800 831 0 0 I.ZOO so so 0 so l3o 0 0 I.ZOO so so 0 so 129 II IDO 2.400 UD0.000 l1.23B.124 127,!IDD 1137.500 128 26 2,117 1,033 12.11e.e6'7 12,1125,000 110,670 11553.SSO 127 13 1,083 2.117 l1.Dll3.133 11.11U67 IOll,162 11.5211.410 126 1 13 1.117 aes.m lttl.867 529,174 12.649.371 125 0 0 I.ZOO so so 544,042 12.720.210 124 0 0 I.ZOO so so 544,042 12.720.210 123 1 100 1.100 1100.000 SZD0.000 527,041 12.8315.203 822 14 1,400 1,800 11,400,000 12.aci>.OOO 806,024 11,!530-.111 121 - 28 UDO 400 12.eao.000 115,IQO,DOO 18.005 134D.D26

• 120 11 1.100 2,1DO 11,100,0oo 12.200.000 144,400 11.722,000 119 9 800 UDO S800.DOO I 1,ICID,000 118,0DO '690.000 818 0 0 UDO so so 0 so 117 0- 0 1.200 so so 0 so 816 5 !500 2.7DO - 115DO.DOO 11,oa>,ooo 226,057 l1,1S>.267 815 0 0 uoo SD SD 0 SD 814 0 0 1.200 SD SD 0 SD 813 0 *o 1.200 SD SD 0 SD 812 19 1,1110 . 1,390 l1,8CID,OOO l1,8CID,OOO . 118,190 11590.952 811 15 1,!500 1.7DO 11 ,500,000 11 ,500,000, 244,205 11.221,025 810 0 0 UDO SD SD 0 SD 809 0 0 1.200 SD SD 0 so 808 0 0 1.200 SD SD 0 _SD 807 0 0 1.200 SD SD 0 SD 806 I eoo 2.400 aeoo.ooo aeoo.ooo - 880.460 11,IQUOO 805 4 400 1.300 1.500 S400.DOO S400.DOO 129.838 S849,1A 804 4 400 1.100 1.500 S400.DOO S400.DOO 186,7415 SISS.725 803 0 0 1.200 2.000 SD so 127,!IDD 1137.500 .

802 17 1,700 1,!00 l1,7a>,OOO lt,7a>,OOO 1115.236 1826,111 801 0 0 I.ZOO SD SD 0 SD eoo 0 0 I.ZOO so* SD 0. SD 719 0 0 I.ZOO SD SD 0 SD 798 7 700 2.500 '700.000 1525.000 78,500 1182.500 797 15 !500 2.700 115DO.DOO 13'75.DOO 111.214 11591,()68 796 2 20D l,000 SZD0.000 1150,DOO 127.!IDD 1137.500 715 4 400 2,800 S400.DOO asoo.oOo 247,526 11.237,131 1M 11 1,100 2.100 It. 100,000 1125.000 114,256 11571.212 793 11 1,SOO 1,100 11.ICID.OOO 1175.000 1IO,Cll8 S800,490 712 15 !500 2.700 115DO.DOO 1175.DOO 1415,1196 1728,482 791 0 0 I.ZOO SD SD 115,564 115771fl2 790 0 0 I.ZOO SD so 73,4<<1 1367.200 719 2 20D 1.000 SZD0.000 1150.000 111.167 11591,434 7U 7 700 uoo '700.000 1525.000 115.1183 $329,417 787 14 1,400 1.100 11,400,000 11,050,000 llS.SSlll 1431,188

• 786 8 IOO 2.eoo MD0.000 8450.000 18.7eo 1483.11118 785 0 0 I.ZOO SD SD 0 so 784 I 800 2.300 14,500,000 13,175,000 50.533 l253.1es 783 15 eoo 300 0 115DO.DOO 1375,DOO 115,748 178,740 TOTAL. 549 151,0CS 1158,891 1,000 1157,f/B7,717 I 199.162.427 1.400.133 147,ooo.ess 75