FLOOD04543

• County: Statewide
• Community: Harrison County, Iowa
• Basin: Statewide
• Title: California Bend Missouri River Fish and Wildlife Mitigation
• Date: 11/1/1994
• Prepared For: US Army Corps of Engineers
• Prepared By: Greenhorne & O'Mara, Inc.
• Floodplain - Doc Type: Data ‎(general)‎

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SEP

e '94 9138

FROM USDA SCS

PAGE.ee2

HISSOUlI RIVlI 'I'H AID VI~OtlFl MITIGATION ,aOJBCT
'ACT sum

CM.IfOUIA IIIID WBTLAIO IAllTA'l' USTOItA'UON
IAUIIOIf coum. IOWA

t.oc.tiOll: TII. California Bane! St.t. WUdUft Ar.a 11 locaceel approxiaaCe1y
fh. iii!.. southwuc of Hod.le in Rarrhon County, Iowa. The ar.a of
Uat.-GWlled land 1.1 approxi..aCely 420 acres iuedhCely .djacent to the riv.r
chenn.l betwe.n riv.r .il.. 64' and 652.

"'oun. Probh., Rbtorically, the area was part of the natural riv.r
cbann.l which consilted of chI Ildn chann.l, tide cbannell and chutel, land
bare, and backltat.rl. Thh habitat was lIDportaot to ..i.ralory watedowl,
Iborebircla, and apaWl\ll11, f..ding, .nd rearl", of native riverine fbh.
Durine conatruccion of the bank .cabilizaCion/navi,acion proj.ct, tb. area wal
cut off frOlD the u1n channel by the cOllltruct10n of clo.ure dik.a and
rev.tmencI. Project Lnduced river bed d.gradation and ..elillentation hat
Ireatly raducad the wetland babitle on tbe ar.a.

Propo'" Projectl Thi. project con.1ata of ChI conlCruction or relloracion of
an inl.t .tructure, a flow-tbroUlh chute, a d..p "ater channel, deep backwac.r
channels, d..p and ahellow water badn., .ha11ow wuer cbann.ls and .hllllow
off-cllannel wetlandl. A concapC deti,n ia attach.d. An inlet acructur.
deaisned to retard tha incroduction of a11t would be eon.truct.d approxiaately
halfway up frolD the lDOuth of Ca11tornh lend (+4.500 ft). An inlet chute
would carry ".ter into a de.p water cllannel which would b. open to ch. river
at the ~outh ot Cal1fornia lend. The deep wacer ehannel would be
approxi~cely 200 tt. wide, up to 4,000 fc. long and have an average depth of
at halt 6 ft. duriO, the winter IIOncha. TIle llow-throu.b chaDnel (1nlet
chute and deep w.ter Channel) would be approxillacely 6,000 ft. 10aa. The area
Dorth and weat of the deep water ehennel would be dred.ed to ruton
approxi.ately 30 Acree of wetl'l'Idl by cr.aCing both deep and aha110w waeer
habitat. rhea. wetl.nd. .hould have an aver... depth of 4 ft. becween April I
and Dece.ber I of each ye.r. The .horeline .1I0uld be 1rre,ular wich levoral
interconnected pockec. of,daaper wat.r. A dlk. (levee) would be con.tructed
basinnln,. at tile 1I1,b bank near the up par end of CaUfornie a,nd aDd extend
alonl C.O.!. dike 700.55 to Cha Missouri River then aouthernl)' along Che
propo.ed inlec atructure. TIlt. dike would cer_inate juat ahort of th. bi.1I
badlt at the .outh .nd of California aend. TIle lower .nd of tba dike would
deflect water flows back loward the rlver. "boatable cllannel would be
maintained between the hi,h bank And the .nd of the dike. Approximately 38
.cr.. of deep backwater channel. and pocketl and 30 acr.. of .hallow water
acre. would ba re.tored. The average depth of the deep water channels would
be 5 fC. during chI winter 1I0nthe. Shallow water areal would &Verage 3 te.
betweea April 1 and becellber 1 each y.ar.

Project JeD.tte.: The pdllarT 10&1 of tbe project would be to reetoft
riverine fi.h spawning, feedina. and rearlft1 habitat. Secondar7 .oal. would
include restorlD. waterfowl nllting, brood r..rill(, ancl ri,rator7 habitat.
Thia would be 'cCOIllP11.hed by increadnS th. extent of the unconeol1dated
ahore, aquatic bed, ancl emergenc wetland cl&8ses. A diversity of aballow and
d.ep water la.bitat. and a connec:tion to che riv.r would prov1d. productive
ofr-cllannel fhll epawnill8 and readng u.... Both Id..ratory. and redelent
wacedowl would benefit fro. tll. increased wetland acre.,. anel throuah the
diver.lcy of vet~anel habitat. cre.ted by chta project.

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