~~\SSIPPI 11ft? ~~ AND -€4 TRIBUT ARIES
DEPARTMENT OF THE ARMY CORPS OF ENG INEERS LOWER MISS ISSIPPI VA LLEY DIVISION Vicksburg, Mississippi S\5SIPPI ~\-r:o AND
TRIBUT ARIES
POST-FLOOD REPORT 1l~13)
Published by LOWER MISSISSIPPI VALLEY DIVISION AND MRC in cooperation with NORTH CENTRAL DIVISION, MISSOURI RIVER DIVISION, SOUTHWESTERN DIVISION, AND OHIO RIVER DIVISION
SYLLABUS
Throughout the autumn of 1972, above average rainfall began to fill fl ood control reservoirs along the tribu tary streams of the Miss issippi River. By December 1972, the basin had become saturated and very linle additional rainfall could be absorbed. Corps hydrologists noted an ominous pattern in hydrograph readings at Cairo, Illinois, the lOpOr the Lower Val ley, where the Mississippi and Ohio Rivers join. In ea rly i'vlarch 1973, morc storms developed over the Missouri River Basin, then moved into the nonheast over the Upper Mississippi and Illinois River Basins. Others blew lOW Arkansas, Louisiana, Mississippi, Tennessee, and Kentucky. On 9 March all indications we(e that a major flood had begun. Later storms in March and April added more fl oodwaters. It took until mid-June 1973 [or the flood to run its coursefrom the State of Iowa to the Gulf of Mexico. The magnitude of the nood varied greatly in the tributary basins,'buton an overall basis and particularly o n the lower Mis sissippi River the flood ranked as one of the great fl oods of Mississippi River history. Federal flood con trol works throughout the basin, although many projens were still under construction, were highly effenive for the purposes for which they were designed and constructed. Reservoirs and other works in the tributary basins reduced local flooding, and the reservoirs combined to lower the fl ood crest on the upper Mississippi River at St. Louis, Missouri, by 2 feet, and the crest at Cairo, Illinois, on the lower Mississippi River by more than 1.5 feet. Private and local non-Federal levees throughout the basin were generally designed for lesser floods and many failed despite efforts to hold them. Although still incomplete, thecompJex Mississippi Riverand Tributaries Project for flood con trolon the lower Mississippi River, overall , performed splendidly. No Federal levees on the lower MiSSissippi were breached, and other features of the project also performed satisfactorily. As the flood developed and stage-discharge relation data were collected and studied, it became apparent that the channel capacity of both the lower Mississippi River and tlie lower portion of the Atchafalaya Basin Floodway had seriously deteriorated. A new Project Design Flood Flow Line was established and it demonstrated the need to raise many miles of levees to provide protection against the project flood. This superimposed a vast emergency levee-raising program in addition to the flood activities already in progress. A permanent levee-raising program based on the new flow line is an absolute necessity. This work is now under way. Corps of Engineers emergency activities during the flood encompassed every phase of flood fighting, ranging from cooperation with small local levee or drainage districts to direct operation of major flood control slruCLUres. On the lower .Mississip pi River, the Birds Point-New Madrid Floadway in Missouri was readied for use, but operation did not become necessary. Bonnet Carn?was again operated successfully. Old River Overbank Structure was used for the first time, as was the Morganza Floodway. . Total damages with existing projects were $1,151,770,000; damages without projects would have been $15,610,193,000; total damages prevented by projects amounted to $11.185,723,000. Without Federal projects 33,768,000 acres would have been inundated. With Federal projects 16,712,000 acres were inundated. The projects saved 17,056,000 acres from inundation. Approximately 15,300 persons were displaced and 28 deaths were attributed to the flood. Over 300 deaths were reported for the 1927 flood. The 1973 flood again justified the Federal flood control projects in the Mississippi River Basin. However, the expanse of areas flooded, the monetary losses sustained, and the extent of human suffering experienced in 1973 clearly indicate the need for the completion of the authorized flood control works, expansion or modification of some existing projects, and the initiation of new projects in some areas.
CONTENTS
SYLLABUS ...... '" LIST OF TABLES ...... VIII LIST OF PLATES .. VIII
Section I AUTHORITY, PURPOSE, AND SCOPE
AU']"HORITY ...... PURPOSE AND SCOPE ......
Section II DESCRIPTION OF THE MISSISSIPPI RIVER BASIN, THE FLOOD PROTECTION WORKS, AND THE IMPACT OF THE 1973 FLOOD
BASIN DESCRIPTION ...... 3 BASIN FLOOD· CONTROL WORKS ...... 3 Tributary Basins ...... 3 Lower Mississippi River ...... 3 IMPACt OF THE FLOOD ...... G
Section II] METEOROLOGICAL AND HYDROLOGICAL HISTORY OF STORMS AND FLOODS
GENERAL II PRECIPITATION ...... II STOR .vIS ...... II DlSCI IARGE RECORDS ...... 12 MAXIi\-IUM D1SCI·V\RGES .. 12 COMPARISON OF 1927 AND 1973 FLOODS .. 17 MONTHLY AND ANNUAL RUNOFF 17 CONTRIBUTION OF FLOW...... 2.1 RESER VO IRS ...... 26 CONTENTS
Section IV EMERGENCY ACTIVITIES
CORPS OF ENCI :-"EERS ACT IV iTI ES...... 29 Gm=l ...... B Acti"jties by Bas in ...... Z9 Bank Fa il ure Emergencies...... :) 1 Fl ood·Fighting T echniques ...... ;")2 ACTI V IT I ES OF STA"fE AGENCIES. LOCAL I NTERESTS, AN D I NDIVIDUALS :)~l Acnvrn ES O F i\IILlTARY UNITS ...... U. S. Coa!>! Guard ...... National Guard ...... Fifth Lt. S. Army 62d Engineer Ba Cl a lio ll ...... P' U BI .lC AI' FAIRS S Ui\Ii\IAR Y ......
Scction V AREAS FLOODED, FLOOD DAMAGES, AND FLOOD DAMAGES PREVENTED
SCCli on VI COORDINATION WITH OTHER FEDERAL AGENCIES
GENERAl ...... 61 FEDERA L DISASTER ASS ISTANCE ADI\ IIN ISTRATJOi\' ...... 61 U . S. WEATI!ER SERVICE...... til U. S. COAST GUARD ... Ii::!
Section VII ANALYSIS, CONCLUSIONS, AND RECOMMENDATIONS OF THE MISSISSII'I'I RIVER FLOOD PROTECT IO N SYSTEM
TRIBUTARY BA SINS ...... 63 i\ II SSI5SIPPI RI VE R AND TRI BUTARIES PRO J ECr ...... 63 General ...... ti3 Channcl DctcrioratiOlI. P roJCCl Design Flood FloI\' Linc ,me! I.ncc-Raising ...... 63 N('('d fOl" i\ [orc Extensivc Flood Prott·ctioll ...... OIl Fuseplug I .c \"lx·~ ...... 69 Old River LO\"-S ill Control Structure...... 69 Early Completion of the \IR&:T Project ...... 69
" CONTENTS
Seepage ...... 69 Pumping ...... 69 Pipes Through and Under Levees ...... 70 Levee Erosion from Wave Wash...... 70 Channel Deterioration on Tributary Streams ...... 70 Liaison with Army Commanders ..... 70 All-Weather Access Roads ...... 70 Stone Stockpiles for Emergency Use ...... 70 Maimenance Support for Army Vehicles ...... 71 Belter Maimenance of All Flood Protection Works 71 After-Action Conference ...... 71
\11 LIST OF TABLES
Table Title
Drainage Areas of the Mississippi River ...... 4 2 Average Versus Observed Precipitation...... 12 3 Comparison of i\!Jaximull1 Discharges of Record and 1973 Flood Discharges 16 4 Maximum Confined Di sc harges ...... 16 5 Maximum Discharges on Mississippi R iver for 1927 and 1973 Floods ...... 17 6 Minimum, Average, and i\!laximum Monthly Runoff in Inches ...... 25 7 Percent Contributions 10 Average Monthly Mississippi River Flow ...... 26 8 Maximum Discharges for 1973 Flood ...... 27 9 Summary of Areas Inundated by Basins, 1973 Flood ...... 55 10 Summary of Areas InUlH..Iat l..>ci by States, 1973 Flood ..... 56 Summary of 1973 Flood Damage and Damages Prevented by Basins. 58 "12 Summary of 1973 Flood Damages and Damages Prevented by Stales 59 13 Original and Adjusted Flow Lines ...... 66
LIST OF PLATES
Plate Title Page
I PreCIpitation, March 1973 13 2 Precipitation, April 1973 11 3 PrujeLi Design Flood ...... l:i SI. Louis, Mo., Stage Hydrographs ...... 18 C,iro, Ill., Stage H ydrographs. 19 6 Memphis, Tenn., Stage I-Iydrographs 20 7 Arkansas City, Ark., Stage Ilydrographs 21 8 Vicksburg, MISS., Stage H ydrographs 22 9 Red River Landing, La .. Stage H ydrographs ...... 23 10 Rainfall by Basi n , Percent Above Normal. Sep 72-May 73...... Lower Mississippi RIver Main Stem. Flood of 1973 ...... "12 Lower MissiSSippi Valley, Flood of 1973
VIII Section I AUTHORITY, PURPOSE, AND SCOPE
AUTH O R ITY
This rt' porl. covering major p has(''i of and under the authorization of the Ch ief of rlooding conditions ex perienced within the Engineers rom a ined in !ctter, DAE N-CWO·[, ;\ Iissi:.:.ippi Rin:r Basin. has 1:x.'t~ 1l prqxll(xl in 5 JUlie 1973, subject: Post-Flood Report, ;!C(:oHb nct' IV it h ER 500-1- 1, cia led 'I January 1974. r-.l is:.i:.si ppi River a nd Tributaries Flooding. I ~i 3 .
PURPOSE AND SCO PIC
I'he purpose of the report is to provide a H a~i n . St'parate appendixes have ueel! plt'pa red rdLT{' nCl' for infQl111;lIiOll n:ialivc 10 the storms, COV(' I i l1 14 thc major triblllary river basins, T hese subsequellt floodi ng. a n d flood-fi)..; llIing append ixes, which includc detailed flood data. proccdun:s prior to alld during the 1m3 Oood. hal'c I)ccll prepared by the Corps of ElIl-;illeer~ Thb report wi ll he of particular valtll' in District or Divisio n having jurisdiction over the {'valuating fi()(Xi-co ll lrol IlL,txls and in pbllnill~ arca involvt.'!1 as Jiswd below. Copies of theappen proj<''Cls ,-('spollsi\"{' 10 these n{"("(is. It will also dixe~ arc on file in the Office, Olier of Engi providv informa tion that will be helpful UI neers. Washington D, c.; Office. Division Engi improvi ng flood-fi ghting proced ures, nee r. Lo wer Mississippi Va lley Di VIsion (LMVD), Thi~ leport prt's\'n!s a summ,uy of fl ood Vicksburg. Mississ ippi: and in the orig inati ng inlorlll;ltion fOl the ('!Hire l\lississippi Ri w r offices for the areas undcr thei r jurisdiction.
ApJX' ndix River Ba sins Included OriRinating Offict'
A Illinois
r ''(, ! i i ,----'j, l
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---,- '._-. -"-. r-"' -~ ,-- ...... __ .__ ~
I ; ./' ( t ,/ ; - . --.- . ---.-~ .-~' ,, Section II DESCRIPTION OF THE MISSISSIPPI RIVER BASIN, THE fLOOD PROTECTION WORKS, AND THE IMPACT OF THE 1973 FLOOD
BASIN DESCRIPTION
Th!.: i\Il~~i ss ippi R iver and its tributaries The l\Ji ssissippi River rises in northelll drall! a tol:d of 1.2'IG.OOO squan: lIliks. which is'l] \ Jill l1l:sota ;md flow s in a southerly direction fo r pnct'1l1 of tile l:lIld ;Hea of till: colltitlt:ntaJ United 2·1:-)0 miles illlo the Gulf of \lexim. The ivltssouri SCIIC'S. :\bOl11 13,000 ~ quar (' miles of til is dra lnage Ri Vl.T etHers the Mississippi River at mile 11.')9 ar('a lIe 11\ two Canadian prOV Ill ces: Ih e remainder :lbo\'(: 1 lead o f Passes, Louisiana, the Ohio;lt mile i~ wi 1h i n the ,!!;cograph Ie boundaries of the U 11 i ted 96·\: and lIlt: WhIle-Arkan sas al mtle 583. Al mtle Slal c.:s and covers all or pan of j 1 Stal('s. Th(' :H 'l.:). so me of the flow le;Jves tilt' Mississippi dr;lltl:lge baslll IS bounded on the \\,('$1 by the RIver through the Old River Control Structures Ro, ky i\]ourHaills. which exceed an elev;IIIOtl of and passes to the Gulf through th e Atchafalaya 10,000 kt:t at many points. Betwe(,1l dlle SC River Ba sin. The alluvial valley of the Missis mounta ins ;Ind Ihe ,\ilssisslppi Ri vnan: lhe Great SIppi River extends from Cape Girardeau, Pbllls. whidl v;u'y in elevation up [0 1000 fee l. Missouri, 50 miles above Cairo. to Ihe Gulf of From the Grea t Ptlins the land slopes eastward La Mexico. This valley varies in width from the Miss iss ippi River. The Appalachian Moun 20 miles at Natchel, Mississippi, 10 80 mties at
tain chain forms the eastern divide o f the walt~ r Greenville, Miss issippi, alld has 311 average width shed. From these mOUlHains the Appal(lchian of 45 miles. Pla te(lu extends \\'estward a t elevations varying T he d ralllage areas and river miles above from 2000 10 4000 fee\. In conuast 10 theeas! and the I-lead of P(lsses are li sted in Table 1 on the fol west divides. the northern ul\'ide is comparatively lowing page for some of the more imponant
ill-defined and vanes III e1evallon from less than local1ons on the MISS issippI River and the 1000 fe et 10 more than 2000 feet. Inajor lnuularies.
BASI N FLOOD-CONTROL WORKS
TRmL' TA/n' B, /SI NS LO II'ER M I5;SISSII'PI IU l l ER
Flood-COlltrul worb ill Ille several tributary Description of the Flood-Control Plan basins consist of va riOll S combinations of 'flte i\ llssisslPPI Rivcr and Tributartes Flood (otllpktnl. partially completed. allli autltoriletl Contlo l Project emhodie~ a plan to protl"lI lite hut no( started ~trullu n' S and 1Il11)l"()H'lllcn (s . Lower ~li~,i~sippi "dlley against the projcn . "llcse works arc lurn prisetl pri In;1 ri Iy or llpslrcalll design flood. Tht' plan includes Ihe lise of levees. res(>l\oil ~ \,'itlt f"Jood-storagl ' ca paciti es, levee~, rt oodwa\ ·~. (hallllc1 IllljHon'mellls, and Ill;ljor floodwa),s, and. JIl SOlllt; cases, pumping- st;ll ions trihutary Ill)otl-u)]l t.rol lmpro\'emenls. '1"11(' ror tlw control or lllllXIlJ1ldcd amI seepage wat!'r project de~lgll flood was dC\"cloped by cO lllbining within protected areas. st" \ el"t" ~tollns of lecord lhat have OCCU lTed III the
3 TABLE I
DRAI NAGE AREAS 0 1-- T HE l\ II SS ISSI PI'I RI VER
Gaging Station l .<)(;; u io n Rivcl' and D,."i nag\: Arca Applic«bl c Gaging Jl.li]es Ahov\: ~k a d AI'\:.I (squarc miJc~ ) Station of Passes. Louisi ana
Upper Mississippi. 17 1. 470 Alton. i1l inois 116i Aoo,'c Alton. Ill inois i\ lissouri. S28,200 Hennann. Missouri 1256 Abo,'c Ilcnnann, Missouri Uppcr Mississippi. 701.010 St. Louis. Missouri IIH Aoo\'c SI. Louis. Missouri Ohio. 203.620 Mctropolis. Illinois 1001 Ahov/! Metropolis. Illinois Mississippi. 921.900 ariro. Illinois 966 Aoo\'c Cairo, Illinois Arkansas. IS8,200 Little Rock. Arkansas H I Alx)\'c LiIl1c ROod.:. Arkansas White. 25.500 Clar'cndon . Ark;m sas 683 ,\oo"c ClarendOfl, Arkansa5
Mi ssissippi. 1,1~1.590 Arkansas Cit~·. Ark:IIIS:'S Aocl\'c I\ rk:rns.as City, Arkansas '" Red, 67.5()() Alexandria. Louisian:. "IXJI'c /\ lcx:rndria, Louisiana ." "'Ii ssissippi. Red River l..;mding 301 1\001'C Rcd Ril'~r L;mding (la titude). Louisi:ma (latitude). Louisiana
basin. and p lacing them in a pattern 10 produce thence th rough the lower Atchafa laya Ri ver a nd the g realesl fl ood Ihat miglll rC'dso nably be Wax Lake Outle!. expeClcd 10 occur. This fl ood will produce 3,030,000 cubic fcct per second (cfs) al the lalitude Levees of Old River. Fl oodwaters from the upper end o f The levee line o n lhe west bank o f the the Va ll ey would pass downstream, confined by Mississippi River begins just soulh of Cape levees or high grollnd except for backwater a reas. Girardeau, iVlissouri, and, except for gaps a t Ncar Old River the fl ow would divide, with a points when:: there arc tribu tary streams o r hig h m a XllnUIll of \ ,500,000 cfs cont inuin g grounds, extends a lmost 10 the Gulf of Mexico downstream to the Gulf through the levCt,'(1 (to mile 10 above the Head o f Passes). channel of the Mississippi River and the Bonnet The area cast o f the river is protected by levees Carre Spillway. The balance of the fl ood fl ow alternati ng wi th high bluffs. Between Hickman. would be diven ed Ihrough the Old River Con tro l Ken tucky, and th e Obion River, the (lrea is Structures and the Morga nza Floodway to the protected by twO short reaches o f levee; one is 22 Atchafalaya Basin, where it would be jo ined by miles long and the other is 24 miles lo ng. water from Red Ri ver and liS tributaries. This Begmning just below i\'lemphis, Tennessee, at the portion o f the flood would pass to the Gulf head of the Ya zoo Basin, there is a contin uous through the lower Atchafalaya Basin Floodway. levee to a point JUSt above Vicksburg, Miss iss ippi.
4 TIle east bank is largely hilly from Vicksburg to strip of land between this setback levee and the Baton Rouge, Louisiana, where the levee begins levee adjacent to the river forms the Birds Point again and runs continuously to the vicinity of New Madrid Floodway. Plans call for the Point-a-La Hache, Louisiana, approximately flood way to be placed in operation al stages of 58 44 .5 miles above the H ead of Passes. feet or hig her on the Cairo gage if a stage in excess The White River backwater area, consist ing of 60 feet at Cairo is forecast. Water enters the of 119,000 acres between Helena, Arkansas, and floodway through a fu seplug section in the front the mouth of the White River, is protected from levee by naLU ral oven opplllg or artificial frequent flooding uy a ring levee which connects breaching. It reenters the main river throug h a with the main-line Mississippi River levee and gap in the front levee justabove New Madrid. The which contalils fuseplug sect ions to permit f100dway has been operated only once, in 1937, Mississippi River floodwater to enter the and it was helpful in reducing flood heights at pro tected area at extremely high stages. Cairo and nearby areas. The Tensas-Cocodrie part of the Red Ri ver Old R iver Conlrol Slruclures- The Old backwater area, containing 372,500 acres, is west River Control Structures are located on the west of Natchez, rvlississippi, between the Black and bank o f {he Mississippi River a t approximately Mississippi Rivers, and just a few miles aUove the mile :1 14 above the Head of Passes. The structures Red and Old Rivers. It is protected from floods by were buil t to prevent the capture of the a loop levee with north and south extremities MISSissippi Ri ver by the Atchafalaya River and at joining the west-bank Mississippi River levee. In the same time to control fl ows into the order to reduce the flood crest at extremely high Atchafa la ya Ri ver and Basin. They consist of a stages, a fu seplug sec tion in the levee will permit Low-Sill Control Structure and a ll Overbank floodwaters from the Red-Ouachita and Control Structure, and were designed to have a Mississippi Ri vers to overtop the levee. combined capacity of about 700,OOOcfs during the The main-line levee terminates just above occurrence of a project flood. Vicksburg, Mississi ppi, where the Yazoo Ri ver T he Low-Si ll Control Structure IS a enters the Mississippi River. The Yazoo reinforced concrete structure consisting of I I backwater levee system has been authorized to ga ted bays, each having a +'1-foot clear width protect the lower Yazoo Delta from backwater between piers. The three center bays have a weir flooding of the Mississippi. The backwater levees crest el eva tion of 5.0 feet below mean sea level are under construction. but the system is not (llls I) for passmg low flows, and the other bays complete and did not provide backwater have;} weir crest elevation of 10.0 fee t a bove illS!. protection during the 1973 flood. The hig hest gage reading recorded for 1973 at Ihe structure was 61.6 feet ms!. river side, on 15 May; Floodways channel side that day the reading was59.3 feet msl. Birds Po int-New Madrid Floodway-From Genera ll y, Ihe gales of the Low-Sill Control Cairo. Illino is, to New Madrid, Missouri, the east Structure remain fully open at all times to bank bluffs and the levee, as originally built on distribute low and moderate flows except when the west bank, left only a narrow channel through specia l conditions require partial closure. The which the river could flow at flood stage. The proj structure was full y open throughout Ihe 1973 ect provides for a setback levee five miles west of flood. the riverfront levee th rough this reach to reduce The Overbank Control Structure IS a the flood heights to which the controlling levees reinforced concrete structure consis ting of 73 above and below Cairo would otherwise be sub gated ba ys, each having a 44·£001 clear widlh jected and to help protect the city of Cairo. The between piers. The weir crest elevation for all bays
5 is 52.0 fcci above illS\. The gates of this Siructure Alchafalaya Dasil! Floodway-Tbe arc normally fully open 10 distribute flood flows Atchafa la ya Basin Floodway extends from the between the Mississippi and Alchafalaya Rivers. confluence of the Red and Old Rivers, which form Morganza Floodway-The Morganza the Atchafalaya Ri ver. to the Gulf of Mex ico. Floodway, located JUSt above the lownof Morgan Gui de levees constructed on the east and west za, Louisiana, and between the Mississippi River sides of the basi n form the noodway, which is and the Atchafalaya Basin Floodway, is des igned approximately 15 miles wide. In the fl ood-cont rol to carry approximately 600,000 d s of Mississippi plan this fl ood way is designed to carry half of the Ri ver fl oodwaters to the Gulf of Mexico via the project flood ( 1.500.000 ds) to the Gulf. These Atchafalaya Basin Floodway, thence through the fhxxhva ters enter the floodway through the Red lower Atchafalaya Ri ver and Wax LIke Outlet. and Old Rivers and the i\lorgailla Floodway. The The control structure is a reinforced concrete West Atchafalaya Basin Floodway, which. in structure approximately 3900 fcel in length sup rea lit y. is a part of the Atchafalaya Basin ported on concrete piles, and consists of 125 gated Floodway. lies parall el to and on the west side of concrete weirs, each 28.25 fee t in width, with a the Atchafalaya River channel. Entry illlo IIlIs weir crest elevation of 37.5 feet ms!. The control floodway is through a fu seplug levee at the north structure is tied into the guide levee by an eanh end at extremel y high stages. embankment. At th e control struct ure the fl oodway is about 1.4 miles wide. Channel Improvements BOllllet Carre Sllillway-The Bonnet c.·urc Improvement and stabilization of the Spillway is locat~'(l l lCa r the site of the old Bonnet channel of the lower Mississippi Riverconstitule C.a rre crevasse and in a straight reach of the all essential part of the flood-control plan. The Mississippi Rivcr approximately 25 miles above dredging and iJ.'1nk l>ta bilization progr.un is \\'ell New Orleans. Louisiana. The spi llway and along but much still remains lO be done. In the structure were designed to convey approximately early 1930's a program of channel cutoffs was 250,000 cfs of fl oodwaters from the Mississippi ina llgurated. These cutoffs would have lowered River LO Lake Po ntchartrain. The structure con ri\'er stages by 16 fee t at Arkansas City ;illd 10 fect ta ins 3&0 bays, each 20 feet wide; 176 of the bays, at Vicksburg at project design fl ood stages. T here in four groups. have a weir crest elevation of arc 16 such cutoffs and IWO major chutcs that 18.0 feet msl, and 174 of the bays, in three groups, den·loped. which o riginall y reduced the river have a weir crest elevation of 16.0 fee t illS!. The dist;\llce bellveen Memphis and Baton Rouge by
structure is approximately 7700 fect lung. 170 III i les.
IMPACT OF T H E FLOOD
In the autulllll of 1972, the residents of the control projects conStructed by the Army Corps of Lower Mississippi Valley had not experienced a Eng in eers had "tamed the river" and made it major flood for more than 20 y~'aJ's. A new impossible for fl oods to occur. generation of Ix'Ople had reached maturity The preliminary ('\,cnls that lecllo Ihe flood without seeing the great river rampaging through of 1973 were subtle, and in the beginn ing thcy the huge basin that it drains. Many of them created more annoyance than alarm. Heavy rains believed that the long absence of major floods was plagued the basin from October 1972 through duc \0 the faci that the main-l ine levees and flood- January 1973. Ri ver stages were abnonnally Iligh,
6 and the river missed its low-water stage almost flood that was already causing problems in these entirely. Navigation and riverfront industries u nprotected areas. Many communities along the began to experience difficulties from swift cur length of the Mississippi and on its tributaries, rent, drift accumulation, wave wash, and other although many were prot('Cted from outside rdated problems. Farmers had trouble harvesting floodwaters, were beginning to have trouble with their 1972 crops. The ground became saturated, interior drainage. Volunteers, local interests, and and runoff was rapid. Tributary streams rose, and State and Federal agencies were kept busy their headwater reservoirs crept up to unusually evacuating people from threatened areas, high lcV(~ l s . strengtheni ng levees with sandbags, and mann ing By the first of February, the Corps was pumps or maki ng repairs. Sand boils had to be preparing for the worst and levee boards and nnged with sandbags and levees had to be other local interests were being urged 10 consider patrolled 21 hours a day. the possibili ty that the spring rains could bring On the upper Mississippi, private levees, about a major flood crisis in 1973. built to protect against lesser floods, began giving Ordinarily it is the Ohio River Basin that way as the river rose toward record heights. makes the heaviest contribution to a major flood Dramatic flood figh ts and heroic effom fai led to on the lower Mississip pi. Corps personnel kept a save many of the homes and communities and wary eye on the g"dge at Cairo, Illinois, but it was devastation was widespread. At West Alton, Mis the upper Mississippi that provided the first flood souri, and at Choteau and Kaskaskia Island the emergencies. Intense storm systems swept over the situation grew more and more critical. M idwest. Major tributaries of the upper At the other end of the Mississippi, a serious Mississippi rose rapidly, and early in March the situation developed very suddenly at Montl, people who lived along the river were already Louisiana, when a caving riverbank threatened a balliing to save private levees that protected their main-line levee. A setback levee had to be homes, fields, and towns from overflow. constructed, and the 44 families who lived in the While the people along the upper village of Montl had to be relocated to new homes Mississippi were beginning a flood fight that was elsewhere. It was the first of several bank failures soon to become a series of critical emergencies, that had to be dealt with, but the later failures preparations were being made on the lower occurred in areas where fewer people were affected reaches of the Mississippi for the flood that was by construction of the setback levees. forming in the tributaries. As the lower Mis In April, the river was well above flood stage sissippi River continued to rise in March, everywhere, and in New Orleans it was rapidly levees were patrolled, floodgates were closed, approaching stages that are crucial to the safety of and flood-control structures everywhere were the city. On 8 April current and forecast made ready for operation. conditions were such that it was necessary to When the Cairo gage reading increased more opperate Bonnet CarrJ Spillway. About 4000 than 21 fee t during the first 15 days of March, it residents of the area, together with public officials became obvious lhat a flood of major proportions and Corps personnel, gathered to see Senator was on the way. As the water rose higher and Russell Long open the first gate. higher against the main-line levees, seepage and In the Atchafalaya River Basin, many sand boils became a problem. As the Mississippi questions were raised about Morganza Floodway, spilled out of its banks, backwater entered its which had never been used. Residents of the tributaries, flooding low-lying unprotected areas Morgan City area, at the foot of the floodway, and in some cases meeting a tributary headwater [eared that the opening of Morganza would
7 Slope protection pavement Orl east-bank Mississippi River levee in jefferson Parish, upstream of New Orlearls, Louisiana overwhelm their city. An emergency fJoodwall threatened Low-Sill StruCture. and levee-raising project already under way in B)' the end of April, the upper Mississippi the At.chafalaya Basin, where levees arc necessarily had produced its third cres t. establishing record built on weak soils and tend to scnle over a period stages at SI. Louis and other gaging stations. The of years. did little to reassure the pcoplcat Morgan flood fights at OlOteau and at West Alton had Cit)'. lx.'Cn lost, as the private levees that had withstood In the midst of the widespread flood fighl, the earlier crests were overtopped by the record swge-discharge data mat could ani), be obtained slages. At Kaskaskia island, the Federal levee under extremel), high-water conditions indicated which had not yet been ra ised to full grade and serious channel deterioration causing man)' mi les section was also overtopped and breached after an of controlling levees in the Lower Mississippi ex tended effort to save it. Basin to be inadequate to contain a project flood. The lower Ohio was flooding; the St. Francis, This necessitated a massive emergency construc White, Arkansas, Yazoo, Red, Ouachita, and tion program to raise levee grades. (See Section Atchafala),a Rivers wereall outof their banks, and VII for more details.) new record stages were being establ ished on some On 12 April another crisis occurred on the of the tributaries. In the flooded areas some of the lower reaches of the river when a wing wall at the homes and buildings were completel), demolished Old River Low-Sill Control Structure was or severely damaged as wind whipped up large undermined b)' the river'scurrents and collapsed. waves on the vast inland bodies of water. This necessitated the almost immediate opening In Missouri, Illinois, Kenlucky. and of Ixlth the Old River Overbank Structure and Tennessee private levees were losl and river towns . Morganza Floodwa), to relieve the pressure o n the bauled seepage and sewer problems and interior
8 Overtopping oj Kaskaskia Isla7ld levee water that sometimes stood several feet deep in nearly a momh. Cleanup operations had begun low areas. In Louisiana, local interests abandoned on the upper reaches, and backwater was an effort to save a private levee south of Jonesville beginning to recede very slowly o n some of the when 20,000 acres of land and 75 ho mes were lower tributaries. By the last week in May, the river inundated as the levee was breached. In the was standing at New Orleans. T he Atchafalaya unprotected Yazoo and Red River backwater Ri ve r rose 10 a record crest of 10.7 feet msl a t areas, water was rooftop-high in some p laces and Morg-d n City, Louisiana, during the same period. residents were evacuated as the water continued to The flood. had lasted 77 days at 51. Louis and 89 inch upward . Near New Orleans main-line levees days at Vicksburg. were threatened by new bank fa ilures and On the lower reaches, with conditions emergen cy repairs had to be made and setback remaining stable, the Corps began the closure of levees constructed. Bonnet Carre a nd Morganza on the last day of Rains colllinued in the Lower Mississippi May. Seepage and sandboils subsided, and the River Basin early in May. The river crested at task of repairing and restoring damaged homes Memphis on 8 May with a stage of 40.4 feCI, and as was beginning on the lower river. Where damage th e crest moved southward, weary fl ood fi ghters was particularly heavy, mobile homes werc on the lower reaches of the river increased efforts brought in for residents to usc until they could to proten areas that had withstood the earlier rebuild. crests. The crest reached Vicksburg on 12 May TIll? falling stages brought on bank failures with a stage of 53 .1 feet recorded. It was the third in the Louisiana reaches of the river and sill highest stage of record. defXlsited by the flood al the mouth of the river By 18 May, the river was falling slowly from created difficulties for ships entering or departing Cairo to Vicksburg, and the upper Mississippi the Port of New Orleans by way of Southwest was reopened to barge traffic for the first time in Pass.
9 By mid~ June it was determined that the One of the most notable aspects of the flood emergency situation had cased, but the lives of was the splendid cooperation that existed between thousands of people had been disrupted and the residents, local officials, and all the Slate and preliminary damage estimates amounted to about Federal agencies that beca me involved in the flood one billion dollars. Almost 17 million acres of fight. This, notwithstanding the hard decisions land had been inundated. The devastation caused that had to be made by the Corps Officers in by the flood was widespread and restoration charge. State and local officials on more than one would be costly. occasion initially expressed grave concern about TIle long, disastrous flood of 1973 has shown some of the Corps' decisions that affected a new generation the awesome power of rivers in flood ways and levees. Later their attitude changed flood, especially of the Mississippi River. Corps to agreement with, and praise for, the decision personnel and local officials who had never seen a makers. Both property damage and human major flood quickly became indoctrinated. The suffering were m itigated to the fullest extent hazards of developing floodplain areas were possible by the Corps exercising its maximum dramatically demonstrated during the flood. The emergency authority, and emergency operations necessity for early completion of the Mississippi were carried out rapidly with sympathetic River and Tributaries and other Flood-Control consideration for the people who were affected by Projects was clearly demonstrated. the 11000.
10 Section III METEOROLOGICAL AND HYDROLOGICAL HISTORY OF STORMS AND FLOODS
GENERAL
The Mi ssiss ippi River Basin has a lOlal arca to 1880. The chief sources of rainfall and runoff of 1,246,000 square m iles and is naturally divided data arc:
into seven major basins: Ohio, Upper " (:1 iula lo logil.d D;H a " h) LT. S. Wtather Burea u . I1 HHllhl)' Mi ss issippi, Missouri, Arkansas, White, Red, and pu bl il,uio ll " 11 )'lllO logh lIul k l;" " h) [ r, S. W""rher Bure"u a1l<1 Corp' of Lower l\Iississippi. Average ann ual rai nfall OVCf EII " III ~'t; r s . lI. S. Arlll},. l11o mhl), p ublication the basin is 30.8 in ches and runoff is 7 inches, o f "~ I olln Rai nl. 11I illlht lI llil l~! SWles" by Corps o f Ell gi 11t ~ ' r s. which more than 90 percent comes from 56 P . :-' . '\ 1111) . I!Hfi
percent o f the drainage basin. In general, the " :-'I. I !ol~ ~ S and l) i)( _ h'''J.; t!~- ;\ l j _,si"jppi Ri,-n O Lllk t ~ aml records o f tributary discharges prior to 1928 T llhlll:lrks" bl .\l ississippi Ri' ef Comm ission. .111111 1,11 p"hli' ,' "OII arc fragmentary, whereas rainfall records (or .. ..,,"f.I( O: \ \',lIl'r Suppl) of Ihe United SWI{"li" b} l ·. !). a larger parI of the basin arc available back (;'~ Ih >!; ll .,1 ~" l"\ t·} . ... "",,,1 puhlic,nioll
PRECIPITATION
Normal annual precipitation over the entire through May 1973 was well above normal for all basin is 30.8 inches and varies according to loca mo nths with the exception of February 1973. tio n from 21.8 inches over the Missouri Basin to february was slig htly below normal. Table 2 '18.5 inches o ver the Lower Mi ssissippi Basin. The shows the to tal rainfall for J\'larch and April to be no rmal monthly precipitation for the basin vari es twi ce the normal rainfall. As shown in Table 2. fro m 1.7 inches in February to 3.8 inches in June preci pitatio n was above normal in the lower and fo r the tributary basins from 0.7 inch in Janu portio n o f the basin from September to December ary fo r the Missouri 10 5.0 inches for the Lower 1972. T o ta l basin precipitation for the g-month Mi ssissippi in i\:larch and the White in Ma y. period was about 35 inches. which is 4 inches Average precipitation, in inches, over the g reater tha n the a\'erage annllal basin entire basin for the period September 1972 precipitation.
STORMS
Storms o \'er the tributary basins that proouce p roducti vc o f flood stages on the lower floods o n the lo wer 1'\'lississippi Ri ver occur Mississi pp i. chiefl y during January-April and. to a lesser 'rhe 1973 fl ood resulted from a series of small cxtent, in i\'!a y and June. Summer storms to moderate sto rms concentrdted primarily in the ordinarily affect smaller areas and arc not usually centra l and west-central po rtion of the basin, The
11 T ABLE 2
AVERAGE VERSUS OBSERVED I'RECII'ITATION
Subbasin
Uppocr :\h ssissippi Ri"er 3.2 4.9 2,3 2.6 2.0 2.6 IA 1.8 14 1.8 1.2 IA 2.2 ~.I 3.0 6 ,9 3.8 6." 20.5 33 .6
Mi,souri Ri,'er 2.6 3.3 1,7 2.0 1.2 2.4 0.8 1.2 0,8 1.4 0.8 0.9 1.6 ".2 2."1 ~ . 2 ~.7 4.1 15.6 23 .7 Illinoi, Ri"er 3.2 49 2, ~ 2.7 1.9 2.6 1.9 3.'! 1.8 1.·1 1.7 0.9 2." 5.7 ' .8 SA 4.1 4.5 23.2 31..'> Ohio Rivc. 3.1 ,,4 3.0 4.2 ~ . 5 6.6 3 . ~ ,>.I 4.2 .1.6 j .6 2.6 4.' 7.3 -L2 8,0 4,5 5.9 33.9 48.7 Arkansas Rive!' 3,2 3.6 2.5 3.8 2,2 4.0 1.9 2.1 1.9 2.8 1.9 1.6 2." 8.6 ~ . 5 3.8 4.9 3.8 24.5 34.1 S!. Franci. Ri'TT 3,2 6.0 3.1 5.7 4,0 6,6 3.9 6-' 4.:' 4.7 4.0 2.8 4.8 R." -!A 106 4.5 9.1 36.4 60.5 Whi,e R i "~r 3.' 6.1 .1.1 5.5 '1 ,0 7,7 3.9 5.4 1.4 4.8 4.0 3.2 4. 6 9.3 4,7 10.5 5.0 6.7 37.1 59.2 Red River 3.0 3,4 3.2 7,6 1.1 5.8 1.1 1.1 '1.1 4,1 3.9 3.2 4.1 9.0 5,2 8.1 4.5 3.6 36.2 '19.2 YMOO R;"el 3.1 4.1 2.6 3,5 4.5 8.8 ',6 7.7 1.9 1.0 5,8 15.2 5,0 R.2 4.1 5.9 40.9 M .R Big Black and Soulh. west T,ihuI.1'';cs 2.9 4.1 2,3 3.2 4.2 4.8 5A 91 55 6.2 5.2 1.3 6,0 10.9 ", I 9.1 ·1. 7 6.7 1U 58,4
Low~"T Mi,,;ssippi Rivcr 2.9 5.0 1.3 7.2 1.2 7,3 4,7 4.7 1.2 3.7 1,9 IDA 1 ", 8.9 4.4 5.7 34,1 :'2.9 ,\I ississippi Ri" er 8".ill 2.7 3.8 U .1.2 2.j 1.0 2.1 2,8 2.1 2.7 21 1.7 28 6.7 3.4 5.7 4.2 4.8 24 ,0 35.4
largest individual storm systems occulTed in that of the 1927 fl ood in thal abovenormal rainfall Man:b and April. Isohyetal maps for these two began in lhe falL proceeded throug h the winter, months are shown in Plates I and 2. The and dimaxed in the early spring. development o f Ihe 1973 flood was very similar tl?
DISCHARGE RECORDS
Stream discharge stations within lhe few of the stations have records beginning in the Mississ ippi River Basin number in the thousands 1870's, but in genera l most of them have records and theIr periods of record vary considerably. A Ihat b{:gin In the late 1920·s.
MAXIMUM DISCHARGES
The maximum discharges of record of the The 1973 fi(xxi was one of the larges t o n Mississi ppi Ri ver and its tributaries vary widely. record; however, major dischargc records \vere set from about 7,000 cfs per square mile for a 1- only on the upper lVlissi ss ippi above the Missouri square-mile basin in the mountains in North Ri vcr conflu ence. Plate 3 shows a comparison Carolina to about 2 d s per square mile for the between the 1973 observed peak discharges entire basi n (1,245.600 square miles) above the Ih roughout the lower i'vtississippi River and the latitude of Red Ri ver Landing, Louisiana. Table j\'li ssissi ppi River Project Flood discharges. 3 compares the 1973 observed pea k discharge with Maximum confined discharges at key the maximum computed orobserved discharges ill stations on Ihe Mississippi River for major key gaging stations on the fiv e main tributaries Mississippi River floods below SI. Louis are and a t fiv e key stations on the MiSSIssippi Rive r. shown in Table 'I.
12 z o ~ I I a. U U a:: w ..: a:: ::;; a.
,,
PLATE , \, I \ ( I, ; z Q (") f- f'. q: Ol f- a: -...J a:: Uw a. a:: q: a.
( -/-._ --_._--.., ) , __~_ , .... " '" I
" --' --+--,," ---._------. ,j f- , " '" ...... ; ..., ~i- ' ''' !I -\--..... -. '-1; <-'-;r-· -".-•. -r , ./ I / J '-~..1 ,,
PLATE 2 .-...,..-~""~"'''' .- .~------.
NEW MADRID FLOODWAY
MEMPHIS
ARKANSAS CITY GREENVILLE
LOCAL
VICKSBURG LOCAL
LOG
~~("""~LA KE ' PONTCHARTRAIN MORGAN CITY
OE' PROJECT DESIGN _ 1973 FLOOD FLOOD I I PROJECT DESIGN FLOOD PLATE 3 TARI .E :I
COl\I PARISON OF MAXIl\I Ul\1 D[SCHARGES OF RECORD AND 197 .1 FLOOD DISCHARGES
.\I.,)I;i'I1"1II FI"ou of RN ,ml 197:i FI""d D j,..-h;ug,· D,,, h.lIg.· R "" I' " ",I Lllcuioll D.lIe (ch) Ih't· I. h i
,\ 1;,,;,,;]>]> ; .11 Ahol1. 11l ;lIn;, l\ !.,) I !JI~ 137.000 AI" I,m :",3:",.1)0(,
.\[;"'"'', ~, I k l m.IIII'. M;".omi J"I 1!.61 676.000 d :\IJ' I~n .',(JO.IK)lJ b .\[,~"" i pJli a, S, . 1n, ,,,. .\I,~;;oud JUI1 1!)I):i I.O.IO.000 \pI I~n K'>~.UII(J
0 1"" .11 ~kll"poli,. IlIlIIois h 'h ]!.ti7 I.K:xJ.OOO OX, 1~12 !1I3 .II(lU
.\I'"i»ippi .,1Cw". I llinoi~ !-t. .. I!H7 1.00'1.000 ,\pI 197.1 !"tl!J.OOI)
.\,k",,," .11 I.il' l<- !~". k. Ihk"" ~,,s I\ pr i!):li ti9:",.OIJlI AI" I~Ji3 .'1~~I.IKMJ
\I'hit!";ll CL"t·odol1 .. \,'''''''''' Ap' 1!1I5 299.{)()() • .\ 1a \" I~Jn I!) I.:!(MJ
,\I;";";I'I".1l , \I~,l1h, ' S Cil~. ,\ ,k;" "", ApI lyon :l,(;!;"oood ,\[;" 19i3 1.lli! J .OI~J
1{t"\I.H .\1<-:1..111111',1 , iMUl".IIl,1 ApI 191~ 233.{)()() AI" 19n 112,000
,\Iis~i""ippi ,11 LIIIIUtic vi Red RI\el 1 ~ ." di l1 g :\1,1\ l yon 1,3 1;"OOO(! .\1,.\ 19i3 2.21i1,{)IMJ
" Fvr Ih t' J"llt' 11111 fluod ;11 I I<-,mal111 (l1 u tii" hal g~ recunl,) ,he flow is " 'I;",.lu ~ I, o b.. , 8!JO .OOO .. k I, !'OJ Ih t' Ap'" li8:, II(lot! a, 51. l.u !li ~ (11" di scharge " ',{)J"tis) ,hl' lIow i, '·, lilll:Ht'd ,n Ill' I ,!!-!O,f)l)() , k ( For ,ht: .\p,,1 I!):li flood a( Clan'lldon (no d;schargt' n't{)rd~) III<' flow i, n ,il11:t,, ~1 (0 I.. , llU,OOU d,. ,I l:.s(illla((~1 ,,,,,f,nNI ulldn I!I:I!) con di'lo n ,.
TAIlLE I
,\ IAX!.\I ! 1;\/ CO:-"'FI NEI) llJ ::'Cl I,\RGES
I S(:1Iioll 19i3-
" 1,( '11i" ~l i' .">LJrj 187 S~!) :n·1 tilO lIiI; IE,2 C"""lllJlloi, 19i1 18110 2002 Ilill 11;21 1:.19 ,\J, !tIl'l,,_, 1"""'It''>5<.'l· :-"'.\ 1711 2020 116d 1',i\6 1633 \']..,111-.." ( :1" , . \I~"'h." ~;, 261:' 2188 1911 li91 11179 \ 'i, ~~h",,, , .\ 1 ;5s i ~5;ppi !\: .\ 22i8 2Oti(J l !r.!'! IlIi6 1%2
l .. nl' IHk 'JI Rt .... I{ " ., 'I 1. ~ lIIdill " 1810 23 1.i Il)'J6 212~ 20,; I Z!61
.~ . \ . "'" ;,,·,,;1 .. \) k .
1 I 16 " COMPARISON OF 1927 AND 1973 FLOODS
Stage hydrographs showing the 1973 floods shown in Plates 'I through 9. Table 5 shows a alld athtT significant years on the Mississippi comparison between the peak flows at these same River at Sc Louis, Cairo, Memphis. Arkansas locations for the 1927 and 1973 floods. City. Vil.:ksburg, a nd Red River L1.nding arc
TABLES
~I.\XL\(LTi\1 [)[SCII,\RGES ON ,\11 55155[1'1'1 RIVER FOR 1!)27 AND 19B FLOODS
1927 Hood" I'm Flood In.-;,I;on Di>chargc (d s) Di"ilarg(' (,f,)
8 ~9.000 tF,2.0()(j
eli l O, [liino j, 1,800.000 1.:,1 lJ.{J(){)
~ k mphi" ' r t ml{'''l'(' I 71 UKiO I.G:H.OUO 2.61 5.000 1.879.000 \ . i<. k ,I" "g . .\ ri " j" it ,pi 2.27Il,(J(}{) 1.96Z.000 1.11;lUd" ,,( R('d RinT L;uHlillg 2.:H :,J)(}() 2.26 1.000
a blim,ul'd ,:o nfincd undn 1939 conditio n, .
MONTHL Y AND ANNUAL RUNOFF
I The average annual runoff for Ihe entire The runoff in inches for the entire basin haSlll is 480 million acre-feet and expressed in above Ihe latilUde of Red River Landing for the terms of depths over the drainage basin is 7.1 period of December 1972 through i'vlay 1973 and mehes. This runoff is equivalent 10 a mean Ihe minimum, average, and maxImum monthly
annual discharge of 657 ,000ds. The mmimum an runoff for the basin are shown III Table 6. The nual runoff is 249 million acre-feet (3.7 lIlehes or runoff for the months shown was rar above the 341,000 ds) and the maximum is 807 million (11.9 average and closely approached Ihe maximum. IIlchl's or 1,106.000 ds). The average monthly Plate 10 shows Ihe rainfall for the enlire runoff for the basin is 40 million acre-feet (0.6 inch MISSISSIppI Basin in percent above normal frolll or 657,000 ds) and varies from a minimum September 1972 through i\ lay 1973. monthly runoff of 6 million acre-feel (0.09 inch or -nle maximum annual flow of record for the 105,000 cfs ) 10 a maximum mont h I Yrunoff of 138 Mi ssi ss ippi River occurred in 1927. and the million acre-feel (2 inches 01 2,223,000 cfs). minimum annual flow o<:cuTred ill 1934.
17 -0 55 , r» I I I I I I I I I I I I .... r------PROJ----'--ECT _IL®JL ------..'" 50
1973 r 40 V BAN~ F U ll V\ .... 30 w rJ. ~ w ~ , V>.... 1972 ~ f\ J: J\ Q 20 1/\ r'\ w " ::r ~ J: \) V w \ (!) .: ~ (!) 'V I ~ \ \; ~ \J 10 1\ '--J \j v \ )~ o -vJ\ ~ J v v.,; rv ST. LOUIS, MO. STAGE HYDROGRAPHS , , , , , , , , , , , , I I ·10 I I I I I I I I I OCT NOV DEC JAN FEB MAR APR MAY JUN JUl
GAGE ZERO FEET MSl . 379.94 65 ------~-PROJECT- r-FLCioi)- t------j ------j-~~-~--~-~--'--~-- ' --~-+- -'--~-l-~-~-- 60
50
-- ..... -BANi >-w w ~ , on >- "rr "" I (!) u.. 30 frW711"r Tht I Y VI ~ OJ I w 1972 V ~ I v 1/ v I (!) IN Yl\J ~ 20 (\/ v \ 10 TV CAIRO, ILL. ." r,. STAGE HYDROGRAPHS .... o I I I I I I I I I I rn ~ OCT NOV DEC JAN fEB MAR APR MAY JUN JUL GAGE ZERO FEET MSL - 270.47 60 -,------r -,------r -,- I I -,------r -,------r -,---, ~" -i m'" ~ ______~_~R9J~~~ ~ _~~9E_ ~ ______+______~ ______4______~ ______~-----~------50 1927 AO 1/~ 1973 ....w w ~ BAN~FUll , ------....on 1926 I 30 W "I w * 20 10 MEMPHIS, TENN. STAGE HYDROGRAPHS o , , , OCT NOV DEC JAN FEB MAR APR MAY JUN JUl GAGE ZERO FEET MSL· 183.91 60 ------PROJECT FLOOD 50 19A5 1973 ------.M~.!5'fW ------AO ....w w ~ V>.... :I: 12 30 w :I: w «'" '" 20 19AA 10 ARKANSAS CITY, AR r;;~ STAGE HYDROGRAPHS --< o '"~ OCT NOV DEC JAN FEB MAR APR MAY JUN JUL G ....GE ZERO FEET MSl - 96.66 ." 60 r - + -~. -~. - ~ . -<--~. -+- ->- -~--'-- -+-<--- -+ - + ->- - -; P-ROJECT- -FtO~D " 1937.____ ~7 '"~ 50 / 1\ / v '0""- 1/ ------.MtJ.!5'fW ------~ ------1926 ~- .- 40 A ~ .\ ---- w w \ / \ ~ rJ\ \ V">.- :I: / (\ (!) 30 / \ KiJ IV ~ \ ~ w :I: w (!)« tv II (!) \1' \ \ 20 1\ \.J (\ 10 l?v r\ I ~ \ VICKSBURG, MISS. r:!:"- J--' , STAGE HYDROGRAPHS o I I ~ , ___J . I I I I I I I I I I I I I OCT NOV DEC JAN FEB MAR APR MAY JUN JUl GAGE ZERO FEET MSl - -46.23 60 ~-~~~---'r-"--'--.---"--'--'-- I u T ------PRO JECT flOOD 1927 50 ______!! 6tJ~f\1l!, t;; ~ \ w ~ 1926 , ~ J: C) 30 W J: w C) « C) 20 10 p v ']V RED RIVER LANDING, LA. ." r 1936 ,.r STAGE HYDROGRAPHS -< 0 I I I I I I I '" '" OCT NO V DEC JAN FEB MAR APR MAY JUN JU l GAGE ZERO FEET MSl - 3.-4 9 ." ~ -< ,i I .---,--.... _- '" , '. l l '\ , o '~_, f < . , ~'"' ----. j' \, ",., '" \..~I'; .... ~. \ ) <-, r . II, i l' '::, _~ __ I r--·--' / __ , ,) _ ";","'1..... --.\L . ---._-.7fII '. , , ' , >.I '- •.• l' , . . '. l 52~ -r - -.,.,, 1J, too._._--- "_. __ , '-r-. ' " ~ ! \, • ", , ,, .•..,< < , <.- ' ----~, .. -•. -.- ~- .--- -.~-.-.--, \\ ,, '-\ , "" ~--- . - ---- , t ...... : ------.,- . \. ' \ .! ., -'\'---1 ~ I ., ,-" --···t······., ;I ... . _~, _~.. .. . ~-----.., \; , I, __ ..... '., ' '\ : - ~ ~ ,, , ',+~ , ~ . ~ ) , , ' ... ; ~ ~I(~., It! l I , -----..... , . I '.- J ' ~ -.' '-._.- •.• _•. J '" 38' J \ \ "i RAINFALL BY BASIN TOTAL BAS IN AV ERAGE 51 ' PERCENT ABOVE NORMAL SEP 72 - MAY 73 L\IlI.E 6 :'>11:\1.\11 '.\1. .\\'~ KACF. ,\:\[) ~l \Xl.\l( ' ~l :'>10:\ lilLY IU ':,\,OH 1:\ !:\Cln .... t l). \ ." 1.21:1.1;00 <;(IU~le milt... .1hO'I' 1.1111",1< R,~1 Ri,, ' ~ '-""II,,),:) Period or R," o,d 1!l i .~ .\[,)11111 ~I"I ;I1HIIII .. h <"I;'I-:'· .\I.'S;'""'" FI<)I ~\ l>n"mlx:, U.12 0.11 09:, 'UI! J",.. " n 0.11 0.60 I.I~ 1.20 h·,,,,,,,,, II.IS O.6~ 1.59 '0; ,\[.11 (h (I. :\~ J {U!S 1.5i 1.12 \ pi it (I. 1~1 U . !.I~ l.K~ I :'>1." H.W U.9i 2.01 lH;" I (lwl I .,~"- 1.:.3 9 .1:, IU~ CONTRIIlUTION OF FLOIV Tlw major portion of Ihe average mean average for the period january through ;\ Iay 1973. momhly flow at S1. Louis, Missouri, is from the The avcrag(' 111(';ln monthly flow from lhe upper i\lississippi Ri ver. cxcept during JUIlC and Arkansas and White RIvers varies from a July when there is a slight excess flow fro m the minimum of approximately II percent of the i\lissouri Ri\"Cr. The contribution of the upper discharge at Arkansas City in July to a maximum ~Iississippi reaches a maximum of approximately o f about 17 percent in June. Forthe 1973 flood. the G5 percent in January. Contributions by the contribut ion from the Arkansas and White Rivers i\·li ssouri and upper 1\llississippi Ri vers at S1. was alxwe average in F('bruary. March, April. and Louis during Ihe 1973 flood period were almost May. For the month of March, the 1973 contri equal. butions werc almost double the avetagc. This The a\eragc mean monthly contribution of above-average inflow added 2 to 3 feet of stage fl ow from the Ohio Rivcr pr<,'ciominatcs from below Arkansas City on the i\lississippi River. D{'celnber through April. reaching a lllaximum of 1"11(' a"crage mean momhly flow from the ;lpproximalcly 76 percent in J 25 I .\I\U 7 I'FRet.:\; I (.O;\;] RIIU ' I IO;\; ... 10 . \\'I:.R . \(,~ \[O;\;TII U ;\II'>'>' .., .... JI'I'I IUn-R H .m\" ]{",I /:: ()U'h)Uld ;\ 11 '''''''; ell , \r~ , III' .• , 1(.. \\').;w .n 1"" ;I\hl,' "I "'l , I.olli, 0 lu0 ,Il (.liw ,tt ' \'~.Ul'." (:il' R,~] R,n', [ • • ,h]II)!; 1" '1io.1 01 1',',.,0.1 01 l'ul<,,1 "I 1'(" i, "I ,,] \Io""h Rt~"I . l 197;\ R . ... vld l!l7 '] R'~"l.l [9i3 ]{",,,.I 1'1,:1 ])('< ,'milt" :It; '0 ~i:; "" 1.1 '0 " J .I 1(" ,II \ ,~', iii ,',!) !:I " Id"((,II' "1,', ,',Ii 12 " " 17 n " ,U ; ,\ 1,"1 It j~) 19 tili ." 12 22 ,\ I" rl :,7 "S ", .\ I." 10'" " " "Hi "19 " " " " " RESERVOIRS At the time of the 1973 flood. numerous The estilllat<:d r('(iunion in slag-e at Vicksburg. flood·contro l alld multipurpose rescrvoirs wcre in O\ lissis!>i ppi. was 2.5± fec i for II le Apri l crcst amI uperation, The majorit y o f thcse H'sclvoirs arc in 1.5 to 2,0 fect for the :\ Iay crest. This is (:quivalent tributary. basin · wick. water·rcsourcc to 17:).000 and 105,000 to 140.000 cfs. res pectively. de\'elopmcllt project s that are desiglled to provide Taulc 8 s h o\\"~ a comparison betwecn the 1973 a large measure of benefit to local p rotection ob~ I\ ('( 1 peak discharges throughout the lower projects in tributary vallqs. but they ,lIso provide ,\ I i~s i ss i ppi Ri ver and what the 1973 peak benefits along the main stem of the i\lississippi d isc harge!> would havc been without tht' existin g" River by reducing the magnitude and frequency of l eM.~r\'Otts III the basin. fl oods. It is cstimatetlthat operation of rest:f\'oirs ,\ la n), reservo Irs l'x perle nced record in the Missouri River and upper i\ lississippi cllTations in flood-control pool. and U) L\ lay 1973 River valleys combined to reduce slages at SI. the majOl it} o f the major rcscnoirs had utililC'd 75 Louis about 2 feet at the crest of lhe 1973 flood. ptTCent or morc of fl ood·control pool capacity. The reservo irs on thc Ohio, T(,llm'ssce, and i\lost of the major rt's('rvo irs in thc basin arc Cumhel land R i \'ers \\"ere o perated to I educe stages located in areas within the jurisdiCiioli of the at Cairo. Illinois. about 3.6 fc-e t for the April crest Ohio Ri v(' r Di\ isio n, i\li ~so uri River Di vision. aTld sli g-h tl y on~ r a foot for the i\ lay cres t. Stage North Cent r;1 I Division, and Southl\"(,s tcrn rcduction !> at Cairo. including: effects of Ih e Di vision, All Divisions COOI1l'ratcd to the fullest :\Iississippi Ri\Tr to St. Louis, \\"Cl"(' cstimated to ('xtCllt possi hlt- 10 opera tc,t hci I respectivc I('sel"\"oi. be ':I.6± fee l for the April crest and 1.5.± feel for the ~y~tl'IIlS 10 (' ffcrl maxinllllTl rc-tlUClion of crest i\lay ClCSt. This is t·qllivalcnt 10 a 265.000·ds ~ t :.tges. I"cdl1c tiol1 in I hc peak discharge at C.1 iro. III i nois. I AUI.E H :\I.\Xli\ll'M DISCllf\RGES FOR 1973 FLoon i\bximllill [)'K h:ngc (ds) Iti,,',. ... ,t! Loc,tion .\ I""",,.i RJ\·cl. I knn;lIIlI. i\li~ .. ",,.i :'00.000 [>60.000 Ohi" R i,,·,.. LHl :,\",:'1 :'70.000 610.000 ()I"., R,n'I, UD :'\0,:'2 9'10.000 1.070.000 Whilt, Ri\u, ( ~I:o,t' .. tI"", fhJ..albas 191.200 ~20,UOO ,\ , J.. ... ",,~ R"l'I , Lmk R( .. J.. . f\' ~.",,,,s ::119.000 190,000 Ltloo Ri'n. Hdow "!I'd,' &')OU 7:',000 1:\0,000 Oll.,ri,i." lti"'I. i\ lo lln .." I ,O lli~i;ltl" H7,')()() H7,!JOO ]{ ",I ]{jHT, Alt'xa"d , L. Lo ui~i,m:1 142,000 l1i7,OOU .\It"". IIlinoi~ .:)3;,.000 ';60,000 ".. I Hili" ;\1,.",,,,, H,'J2.000 910.000 ( .111(1, 1 11.noi~ 1.:'19.000 l.i81.(jOO \k"'plli\, 1-"11"'''''''''' 1.633.000 1.883.000 . \,.J.. _II " .I~ Cj,~ _ .\,1.111'_" 1.1179.000 2.0:-.0.000 \'j, hhur". :\Ii,~i"ippj 1.%2.000 2,102.000 :X.url"". Mi _"",;pp' 2.017.000 2.1:'0.000 1,,"llllti," of R" ,I R" " , Lmtiin" 2.261.000 2,3!11 ,!)I)(1 " I ~ "irnal~d "",siml"" ,1 1"1 •.• r,,,,· wilh ,.0 rt"s<::r,o,r. i .. Ihl, ;\Ii"i~,ippi R,,{'r Ib,in. 27 Section IV EMERGENCY ACTIVITIES CORPS OF ENGINEERS ACTIVITIES GENERAL Corps personnel were engaged in emergency operations in most areas of the 2300-mile-long Under the statutory authority of Public Law Mississippi River Basin, at a cost of (PL) 84-99 the Corps of Engineers has a con approximately $50,000,000. Some relatively new tinuing reslxmsibility tosuppon local interests in methods and materials were used in the flood a ll phases of flood fighting. In order to carry out fight, and they are described later in this section. its responsibilities, the Corps maintains a com The Corps provided 14,000,000 sandbags, 6,800 p lete flood emergency operation plan which in rolls of polyethylene, and 616 portable pumps for cludes every ech elon o f Corps command, from the flood-figh t effort. There were 45,300 persons the Office, Chid of Engineers, to remote field evacuated from flooded or flood-threatened areas. offices. It includes organization charts with Corps of Engineers personnel involved in the assignments of key personnel by name as well as flood effort numbered 2,217, and approximately the availabili ty of Corps construction and support 15,600 man-days of work was performed by the equipment and supplies. Plans include support Corps for the Federal Disaster Assistance by other G.nps Divisions and private contractors. Administration (FDAA). In the LMVD where the An advance preparation program of planning and flood fight was most severe LMVD personnel were training in both technical and administrative supplemented by 289 Corps employees from other fields is standard procedure. Divisions. PL 84-99 also authorizes the repair or Increased emphasis was put on advance restoration of any flood-control work threatened preparation measures in the LMVD in January or destroyed by flood determined to be necessary and February of 1973 occause of the abnormal by the Corps of Engineers for the adequate func high stages of the Mississippi River during the tioning of the work for flood COntrol. During and period of October-December 1972. A Division immediately fo llowing the flood, the Gxps of En wide flood-fight exercise had already been gineers repaired private and Federal flood-control planned for February 1973; however, more works in the LMVD at a cost of approximately emphasis was placed on the exercise becauscof the $92,000,000. The required additional funds high-water situation. Another advance were appropriated by Congress and were handled p reparation measure taken by the Division expeditiously at all levels within the Corps. Engineer, LMVD, was to direct his District Engineers to make a thorough field inspection of ACTIVITIES BY BASIN all major flood-control works and to conduct a trial operation of the major structures that arc A brief account of Corps activities operated and maintained by the Corps. Plate 11 throughout the Mississippi River Basin is given shows the location of the principal flood-control below. More detailed accounts are given in the works in the lower Mississippi River. appendixes, which are available as indicated in From the first of March until mid-June 1973, Section I under Purpose and Scope, page I. 29 " H~~ .~.- <:-;>- " ,I :-~J;_ L VAXOo ~""$Io! __ ~.u ,.-...... ~,II lin .. --"'...... - .- LOWER MISSISSIPPI RIVER MAIN STEM MUteO LOCAT ION OF FLOOD CONTROL STRUCTURES PLATE 11 Upper Mississippi River Basin damage 10 the levee system. The river was closed to Flooding on the Upper Mississippi River commercial traffic during two different periods Basi n (above Cairo. Illinois) was severe and of for a total of 37 days. This closure was to prevent long duration. However. no fl ooding to any great wave wash damage to the levees and riverside extent occurred above the Minnesota-Iowa state structures. The RI..-d. Cross established a flood line. and only $ 12,000 was spent in the state of fight center at Grafton. Illinois, near the Wisconsin on the fl ood eHorl. confluence of the Illinois and the upper iVlississippi River tributaries in the sta tes of i\Ii ssissippi Rivers, and it became a center of Iowa and Illinois began flooding the first of activity for other fl ood-fight o rganizations. This january 19i3, because of ice jams and above center was eventuall y staffed by representatives normal stream flow. Flooding continued through from the Red Cross, Corps of Engineers. jersey I june because o f heavy rainfall, and Corps County Sheriff's Office. Illinois Conservation personnel were dispatcht.:d 11110 the fi eld to assist Department, and the Illino is National Guard. local interests in fl ood-f;ght operations. The T he Corps was the prime contributor of tremendous effort put forth by local interests with equipment and tools used to fight the fl ood. Over Corps assistance was not enough in most cases. 30 pumps. 1.1 million sandbags. 350 rolls o f 'fhe private levees of the upper Mississippi. above plastic. 400 life preservers, and other equipment G rafton. Illinois. were for the most part breached were uilimateIy committed to the emergency or topped. and tremendous damages occurred up action. Of the 18 private levees along the lower and down the river. portion of the Illinois River, S were overtopped. fi were breached. and the remaining 7 were saved. Missouri River Basin T he Missouri River Basin contributed heavi Ohio River Basin ly to the flooding on the lower Mississippi River, The first of the moderate flooding on the but floods of record proportions were not reached. Ohio River in the 1972-1973 high-water season TIle maximum discharge at Hermann. Missouri. began in December 1972. Barkley and Kentucky was 500.000 cfs compared with a record d ischarge Reservoirs were operated to lower stages on the of 892.000 cfs recorded in 1844. Corps flood-fight lower Ohio and lower Mississippi Rivers. From activities were limited to the lower 2S0miles of the j anuary through june 1973, heavier flooding Missouri River; they were begun on 6 March and occurred. From IS through 17 March, heavy rains lasted through 9 April. Corps personnel were dis fell over the southern portion of the Ohio River patched to gather stream data, patrol levees and Basin. and during the period 26-31 ]I.·larch more roadways, establish liaison with local interests, moderate rains came. Flood-fight activity was and distribute sandbags as needed. light in the lower portion of the Ohio River Basin. The Ohio RivCf contributed significant ly to the Illinois River Basin flood flows on the lower Mississippi; however, it Early in March 1973. Corps personnel were did not contribute a proportionate share of the deployed into the Illinois River Basin where they water that might be expected during a flood of the provided assistance and advice to local interests. magnitude experienced during the spring of 1973. The Illinois River Basin consists of hilly farmland terrain with a limited (]oodplain, most of which is Arkansas River Basin protected by local interest levees. A concentrated Emergency activities in the headwaters of the effort was required by local interests, Corps of Arkansas River Basin were extremely limited with Engineers, and volunteers to prevent excessive only minor efforts being required. Beginningon !1l MISSISSIPPI RIVER FLOODING Fabius dramage district, north of pumping station 011 FabIUs levee, looking upstream, 23 April 1973 SllY Island drainage districl, burlap used to stop erosion caused by seepage 011 land suie of levee upstream from pump station No. I, looking downstream, 28 April 1973 /lallllibal, Missouri, loohlllg east all /lighway 36 from faa/ of Mark T wain Memorial Bridge toward East Hanllibal, 1lllll0H, 28/1Pn11973 MISSISSIPPI RIVER FLOODING SOlllli end of Cape Girardeau, Missouri I Commerce, A'lissouri '" -, " •. f-lig /l way 94, l.-vest Allon, M issouri Dislocated residence, Chouteau Island Emergency fJonlooll foot bridge assembled by Army personnel from Fori Leonard 1I'00d, M /.5sotm I I , L" ," j I I r , J ~ • r i Cedar City, MIssouri, and jefferson City, Missotm (right ball h), Missouri R IVer mile 144, 5 june 1973 36 Kampsville Ferry Landing closure, Highway J08 and Eldred levee, 26 April 1973 • --'" H ighway 100, South A'Ialll Street, Kampsville, II/inois, 28 Aprili973 3; 23 April, levees were patrolled between Fon Smith required sandbagging and pumping to protect and Pille Bluff. ;Vlinor flood-fight problems residences. The town of jonesville, Louisiana, developed in North Little Rock, Arkansas, where which IS located Ul the Red River backwater area a pumping station failed to operate properly. On was protected from flooding by a Corps levee. 24 April, when flood flows reached 300,000 cfs at Like most COHlillU llities in recelll years, joneS\'ille LillIe Rock, Locks 8 ami 9 were closed. On 25 has grown. and outside the protected areas there April, Locks 3 through 7 were closed to traffic. are several industries, a hospital, and residential Locks 7 through 9 were reopened to traffic on 27 areas that were endangered by flooding. A April, and 3 through 6 were reopened on 28 April. Louisiana Department of Public Works levee was Below Pine Bluff the levees were patrolled from 2 held as long as possible to protect the oUilying ;\ larch to 15 june. No major problems were j onesville area. On 18 April it became apparelll encountered. that lhat levee would be overtopped, and constructlOll was begun on an emergency ring St. Francis River Basin levee around an area JUSt west of jonesville, to Flooding in the St. Francis River Basin was provide protection to the previously memioned not significant until 16 April when torren tial hospital, indusu-ies. and residential areas. Corps down pours pelted the area. In some areas as much of Engineers personnel and equipment assisted in as 8 inches III 8 hours were reported unoff icially. the construction of the ring levee. The levce 'rhe cities of Paragould, Piggott , Ma rmaduke, fUllCiioned well a nd prevented nooding of the Madison, and Wy nne, Arkansas, were a ll under area. tlueat of floodlllg during this period. Corps Some difficulty was experienced with the employees provided technical advice and Bayou Cocodrie floodgate, a five·ga ted structure salldbags. pumps, and o ther materials to local in the Red Riyer backwater levee. At times the Red imerests. No levee failures were observed, and River was as much as 10.4 feet higher than the flood damage was light. impounded water. Leakage developed lhrough lWO of the gates, but was successfully stopped by White River Basin Corps emergency operations. On 3 May 1973, Corps employees began levee patrols a nd Corps offiCIals decided to raise 36 miles of Red o ther em ergency opera tiollS on the White River Ri ver backwater lcvee~ 1.2 feet to protect aga inst above Georgetown, Arkansas, o n 20 April 1973, an ticipated wave wash as Lhe level of the and on the lower \Vhite River below Georgetown b,lLkwaler continued to rise. \V here borrow on 23 April 1973, providing assistance as required material was available a small levee referred to as a by local interests. This consisted mainly of "potato ridge'" was constructed by borrowing providing advice and eq uipment in the form o f material from the backside of the levee and sandbags and pumps. None of the p roject levees p lacing II 011 the crown. In some cases, the levee appeared to be in any danger at any time during section was not sufficient for this method, and the 1973 flood. Some basement flood ing due to approx imately 7000 fee t of levee was raised by the seepage and sewer problems in populated areas use of sandbags. T wellly·threc miles of levee was occurred; however, damages were very light. protected with polyethyielle film to afford added protection from wave wash. One of the larger Ouachita River Basin pumping operations of the flood look place in the Major fl ood activi ties in this basin were Bayou Cocodrie area. With the sump gates dosed, limited to the lower reaches of the river. Some impounded water from interior drainage was subdivisions north of Monroe, Louisiana, steadily rising. A total of twenty 12- and l6-inch 38 Arkansas River flooding, soulh of Wichita, Ka nsas, H olida y Lakes area White R iver flooding in v iewity of Cw,uroads, Arkansas 39 pumps wen: placed in service on 28 May, and three different locations along the Red River near pumplllg continued unnl 21 June 1973. During the towns of AbbingtOn, Monda, and Lake End, this period a relatively constant water level was Lo uisiana. In seven different locations, maintained. emergency revetments were placed on the banks of the Red River in lieu of emergency levee setbacks. Red River Basin Since regular revetment work was scheduled for No significant emergency activities were these locations in the future, regular project funds required in the Red River Basin above the Texas wefe u tilized. Sorneadditional costs were invo lved Arkansas state line. The lower Red River, below due to the emergency nature of the construClion. Texarkana, however, was a major fi .,." • ~~.," ...... - - •• - . '-...... Backwater flooding ill lower R ed H.iver area, Louisialla 40 Yazoo River Basin possibility that these levees could be overtopped The 1973 flood fight in the Yazoo River Basin by April rains. These projects utilized plywood beg T he MR& r Project has sen·t:d ;I(frnirably 10 protcct the Va lley from Cl majordi"mer in 19i3. E,en so. !looding of "·riOIl~ proponions has occurred throughout th,. V;. lky in areas where lhete j, no ;'''lhori/.(,1 flood prolection OJ where the ~Ilthoril.l"{t pro(ection has not ye( bl't'tl conMmncd. lkc;,usc of the heavy rai", ,,"I,id, ;'ccompany the buildup of a flood sitllation. Ihn,. has also lx"Cn considerable flOlKling from impolmded walelS in prmened an:", h,l\"ing gra' i() drainage outlets hut nO I""nping pl;",(s. This is partin,!;,rly Ir"e i" theaTeas prOll"Cll"{1 by lhe lewes in the St. Louis District. Ihe TCl1sas·Cocodrit·levet' in the Vicksh\lrg Dislrict. and (he Poituc COllpt:e Jeve,. in th e New Orleans Distrid. T he scope of our flood fight !""'e'geney work was required not only by th,· ~\lsta in cd high slages throllghol1l the 'y,t" !!l. incl\lding record stages on the IJpp!"" j\.·li .,sissippi. IIlil1ois. and A(r.hablay" Ri"ns. bUl by the potential which exiMcd for even greater. ca(astrophic flooding. For ",·er IWO Illonths II..., 'H"i" stc", was perchcd cxtremcly high. the gro,md ,o;,ked, ;",d all the lribu(at ies. reM:l"voirs. ;" ,d backw3tel stor"ge arl';'S wne full. Under these condi(ions. addition,,1 r"inbll in oncor moreof tht major tributary oasins. normally to he eXJX"Cwd lhis time of (hI' ycar. could have easily brOllght on increased flows approaching the projecl flood. The sole prOlt"Clion upon which the V"lley d~pe"d,"{1 was tht MR&T )'mjtct. which is less (han 50% complete. There w"'. however. no panic among the impcrfl'n I)" proll'Ctm people, oo;allM! they had tveryconfidence (hatthc Fmcral projl'O and tl". Corps would proted them. In a flood figlll. tillle is pn,.-;ious. opportuni(ies are fk"Cling. ;J!lt! IIn,,,uicipatt·d t''''ergtllcies are ,Hlt;lldillg. If ~Ollltl hin g may hal·e (0 be done. il must be done in ,,{h·ance of (he (illle when lhe need is obvious. My d.'Cisioll was to prepare for a major flood fight. t 1ndn lhesecitlUIIl!itan .. es. il wa't·S"'·"li;!!. as the "we,onW lIalure of the flood lx..:ame deal. 10 get Ilndn w;'y a massivc program of "!llergen.-y construct ion to preserve lhe integrity of our flOO{1 cO lI(rol works and 10 gi,·c 'IS" fighti ng chancc to 5;,n· the Valley. \\.• , could halT procceded less aggressively than w.· did. doing no more than was immediately nen'ss;''')". ami (rying piITl'llleal. to h"t"p ahe"d of prcdiclm slages. The prohahi1ity of failure of s'Kh;, ·brinkmanship· poliq wa, too grc;u. We prepared our floodw,"p. We raised ddicil·llI InN·, a"d floodwall,. \\,,, .~sta hli ,hed continuous contact Wilh 11,, ~ llwdia (0 keep a free flow of infor",;,tiOIl to Ihl" p<"Ople of tht V;rllq. Setbacks. wave ,,"ash, ·]>OWlO ri dge,: mud box(".,. she"1 pile. tic. became lhe 41 LUIgu"g~ of Ih~ Some other Corps emergency aClivlties on the at 55.7 fee! at CaHO and operation of the floodway Lower iVlississippi were as follows: was no! nccessary. Birds Pamt-New Madrid Flaadway Bonnel Carre S/)iliway-Bonnet Carre Mobil ization of Corps flood-fight forces was Spillway is located 25 miles above New Orleans, initiated north of Memphis on 16 March 1973. Louisiana, ;md is deSigned to convey 250.000 ds The Birds Point-New jVladrid rIoodwa)' sector from the Mississippi River to the Gulf via Lake was a prime area of concern. On 22 March, the Pontchartrain. Early in February, dredging to decision was maLIc to raise the elevation of the remove routine si ltation was begun in the forebay upper fuseplug reach of the frontline levee to area preparing for the possible future usc of the withstand an elevation equivalent 1060 feet on the spillway. A second dredge began work on 18 G,iro gage. This required raising the levee i\ larch, and on 3 April the third dredge began approximate! y 2 feet for II III i les. W ilhin 46 hours degT 42 BONNET CARRE SPILLWAY OPENING -- .r _ . , f'IIt' ~ .. -, ...... - .. . 11 April. Operation was successful III preventing opening on April 17 had been coordinated with excessive flows past New Orleans. The maximum appropriate Federal, Slate, and loc spillway had been used since it was constructed III activities beg,m in the Atchafalaya Basin on 2 1931, having been previously used in 1937, 1945. April 1973. although preliminary activities had and 1950. been under way for over a month. MorgllllZa CO/ltrol Structure-On 16 i'vIarch Levees and Floodwalls-Since many of the 1973, Corps of Engineers forces, using Corps levees III lhe Atchafalaya Basin were below grade, equipment. began to degrade the "potato ridge" some levee raising commenced e I Morganza Control Structure during operatIOn 44 LEVEE-RAISING PR OJECT S Steel sheet piling used north of /Horgan City, L OUIsiana, East Atchafalayn Basill proteclion levee COllst ruclion of mudboxes atop floodwall at Murgan Cily, L oumann, by U. S. 5th Army, 62d Engineer Battalioll, Fort H ood, T exas M OUG AN CITY. LOUISIAN A Mudboxcs atop floodwall Atchafalaya River at Morg(H1 CIl)" Lou/sialla project flood flow line which was devciopl'<\ in Engineer Construction Battalion of the Fifth U. S. 1963. Wilh lhe new flow-line information, the Army, Fort Hood, Texas, which was mobilized predicted flood flo\.,.s, and the possibility of ,. specificall y for lhis mission. projeu flood imminent, Corps officials ordered Morganza Floodway-On 5 March 1973, addi tional raising of the lower Atchafalaya Basill nolices wt:re mailed 10 people living in or having !c\'Cei> ami flooclwall s tu provide the n:quitcu an interest in the Morgan/.a Floodway, Wesl freeboard elevations. The flow line cstabl ished Atchafalaya Floodway, Atchafalaya Basin from lhe hydraulic model and computer analysis Floodway, and the Bayou des Glaises Loop. The was used as a hasis for determining the rC(lu ired notice is an annual reminder to the interesu... d elevations and to lOCate Lhe deficient levet' panics thai they aTe living oropcraling,' business sections. Floodwalls at Morgan City and Berwick. in the flood way. On 21 March 1973, the Corps sent Louisiana. were detcrmin(.'d to be deficient and tClegr I, _ t I• --- - Wildlife rescue operatiolls 48 OLD RIVER CON TROL S TR UC T UHES ...... -, .- Overbank and Low-Sill C01llrol Struclures Emergency repans, rock dike al failed wing wall, Low-Sill Conlrol Structure bays o f the Morganza Control Structure were commenced. It was completed on 3 July when all opened. The onrush of water exposed several lhe water in the [OI·cbay had been drained. problems, includingadverseeHeClson the wildlife Pointe COllpee Loop-The Pointe Coupee which did not have time [0 relreat from the rising Loop area contains 80.000 anes of farm l.md. T he waters. The Po inte Coupce Drainage StrucLUre area is completely encircled by levees andcontains was temporarily preVentL>d. from closing by the a si ngle gravity drain structure, which empties malfunctio n of one o f the gates. Because of these directl y in(Q the Morganza Floodway. Wh en problems, Morgama was tempora rily closed Morganza was put into operation, it became durin g the nIght of 17 April and early morning of necessary to close the gates o n the Po int.e Coupee 18 ApriL Then ag'..I in, during the morn ing of 18 Structure. A tcmporary malfunction o f the Apri l and early morning of 19 April, '12 ba ys were st ructure gates allowed a small amount of reopened a fter the closure of Pointe Coupee fl oodway water to back into the protected are-d Drai nage Structure had been accomplished. On 19 until closure could be made. Beginning the day April. 32 bays were again dosed in order to reduce before the structure was closed and for the next adverse eHects on wild life in the Morgall la several days, a lOtal of 13.6 inches of rai n fell in Flood way. Ten bays remained open. On 13 l\'lay this area threatening to raise the water in sump the opening of addit ional bays o f the cOlllrol above the flood easement line. This resul ted in the structures was begun to reduce the effect of rising most spectacular p umpi ng operation of theentire Mi ss issippi River stages on the damaged Old 1973 fl ood. A total o f 'II pO rlaule pumps, ra ng ing Ri ver l.ow·Sill Contro l Structure. T wo bays per in ~i1f' from 10· tn (iO·inch disch,lfgf"s, a nd having day were opened u ntil a total of 20 bays were a tota l rated capacity of approximately 1400 cfs, opened o n 17 May. Operation of the structure \,'ere USL-tl. Pumping was begun on 18 April and continued as required umil 2 June when dosing completed o n 15 June. Pointe COll/)ee Loop pumping operatiolls so BANK fAILURE EMERGENCIES material and construct a setback levee. There \.,.'ere four setback levees constructed during the flood Bank failures, of whatever nature, that emergency in the Lower Mississippi Valley. The jeopardize protective levees are always a threat northernmost one was at Pointe Pleasant. mile during floods. Major bank failures occurred in the 205; the others were located at miles 130,86, and 35 l.ower i'Vlississippl Valley during the 1973 flood at on the Mississippi River a[xwe Head Gf Passes. lour locations. The immediate remedy for a levee Louisiana. Three additional setback levees were threatening bank failure is LO arrest the bank required as a result of bank failures after the flood recession with stone or any other available water receded. Bank failure and COllstructlOlI of levee setback, mile 35 AHP, MIs sissippi R iver levee, vicillity of Nairll, LOUIsiana Naim levee setback completed, right descellding bank of the Alissi.Hippi R,ver 51 "-LOOD-FIGHTING TECH N IQU ES 1973 throughout the entire flood area . The most common method of combatting seepage erosion 'rhe 1973 fl ood fi ght utilized a combi nati on of levee slopes is to excavate ial('ral drains to of old and new methods of flood fighting. The collect the water and lead it away from the affected sandbag was still prevaleru in all fl ood-fi ght area. Sand boils arc normally ringed either by areas. but mall)' IICW methods were imroduCl'(l to sandbags or in some cases by metal drurns orother aid the sandbag operation. Polye thylene (jI m was means to provide a ring around the ooil. and thus used extensi vel y. sometimes as liners for a create a head to reduce the flow o f wa ter so that it sandbag le\'ee to provide watenight protection. carries no material. If the flow of water is no t and som etimcs as wavc-wash protcctioll carrying ma terial , a boi l normally requires no measures. i\ ludboxes and flash boards wcrc uS{'(i to protective measures. If a boi l is ringed to create a raise miles of Icvcc. and they werc sometimcs head. the head should not be excessive. and no prefabricated in panels and assembled all the site. attempt is made to completely SlOp the flow of Portable, wheel-mo unted pumps powered by water because it will break out el se where. Wave farm tractors. were in great demand during the wash on the ri ver side of the levees is a common en tire flood -fight opcratio n.Their usc pro tected problem during fl ooding. TIle wave aCl io n at the man y communiti t's from seepage and interior wa terlin(' tends to scour and ('rode into the le\'cc drainage accumulations. The vast expanse of the sCClio n. One of the mOs t common method s of 1973 flood pro vided an excellent opportunity to combatting wave wash is by placing sandbags a t tes t the usc of modern construnion equ ipment for the wateriill(,. This is not always s.."llisfa ctory, such items as levee raising and degrading because th(' wave T ypical exam p le of a sand boil, ringed wit h sandbags to crea te enough head to slow the flow 52 is to construct a mattress or a fence at the material from the land-side slope of levees to the waterline. Snow fencing can be laid at the crown to prevent overtopping resuiled in sav waterline. anchored down by sandbags or other in g several levees in the Mississippi River Basin. mcans. and will effeClively break up wave a<:lion. Tracks left on the land side by the equipment Nylon-reinforced polyethylene sheeting proved were prone to col lect seepage water which initially vastly superior to the more common 6-mil variety. resulted in a serious problem. This was solved by The procedure o f using bulldozers to push dragging with a heavy rail to smooth the surface. ACTIVITIES OF STATE AGENCIES, LOCAL INTERESTS, AND INDI VID UALS The pnmary local interests with whlch the State and local police agencies. state highway Corps dealt were the local levee and drainage departments. county highway departments, state d iscr ict boards and ci ty administrat ions. Many of Civil Defense officials. and others were active in these officials had been associaTed with flood all flooded arcas. Civil Defense officials. acting at protection activities for years and were very least in part 0 11 lIlformatioll supplied by the proficient in their emergenLY work. Some of the Corps. evacuated flood areas and performed larger and less affected levee boards were a ble to essent ial services as liaison centers for flood -fight conduct the flood-fight activities without efforts. Volunteer labor from high schools and appreciable assistance from Corps personnel. colleges were extremely helpful. Appropriate Others required large-scale Corps support from governors. members of O.mgressional delegations. the beginning of the emergency. The small and other interested stale and national officials dralllage d istricts were. for the most part. pressed were mformed prior to major anions. to the 1I1Tllt s of their resources. ACTIVITIES OF MI LITARY UN ITS U. S. COAST GUAND in many ways dunng the emergency. They provided protection against looting. helped with Coast Guard personnel were active in many levee maintenance. assisted in evacuation. and areas during the floodi ng . They performed rendered many meaningful services. services such as evacuation. rescue, tran sporta t ion of matenal and personnel. and control of FIFTH U. S. ARMY waterborne traffic and were very helpful during 62d ENGINEER BATTALION the emergcllC Y. With a critical flood situation threatening the NATIONAL GUARD Morgan City. S1. I\-lary Parish, Louisiana. area, the Division Engineer. LM VD, through the Office National Guard troops were made available of the Chief of Engineers. Washington. D. C. on by every state involved in significant flood-fight 19 April 1973. requested that the 62d Engineer activities. Na1ional Guard personnel were utilized Battalion. Fon I-lood. T exas. be committed III the 53 t Bulldozers operated by 62d Engineer Batlalioll were rf/ecilVf' /11 It>l'u- rlllsmg opera/IOns, Morgmz City. Louisialla Morgan City a rea under PL 84-99. ;,('(\ion. hauled ami placed 6430 cubic yards of The 62d Engi neer Banalion arrived at shell on le\'ee road:., consnuctcd 2.76 mile:. o f i\lorgan CilY on 22 April 1973 and rcntlen.:u flashlx)artl protection 011 the Morgan City back aUlstanding flood·fighting assistance until 12 l e\'t.'t~. and also cU!l ;, lructed mutlooxc;, amp !\lay 1973. During [his period the battal ioll floouwall ... al \ ;11 IO U!> lOcal ions. surn:ycd approximately 38.5 miles of levcc cross P UBLIC AFFAIRS SUMMARY Early in i\I'll ch 1973, when il appeared \hal a Assistance to the press was well received. and major flo()(l might be imminent. the basic publi c a persona l working rel at io nship was in effect affa irs plan. bas('(1 all ex isting regulations a nd throughout the period. City, county. and state amplifit..'d 10 meet expanded sen 'ices. was p lac(.'tl officia ls wert kept informed of newsworthy ilcms into effcct. Various poillls of contact fot local and as Ihey occurred. na tional news med ia were established. Public mC'Ct ings were held a t various times ;Uld til{' d fects it would have 011 Centers. At lIla n y of these briefings. loca l ;t nd llwir property. This ella bled them to plan for any national news lllt:dia were III att tndanct'. emergency. Oweragc by all the networks. including the The responses of both the public alld the British Broadcast ing Company. and the national news media \\'(,1(' \(''I"y favora ble to the public press was signifiGIIH. increasing in p1'OpOI lion to affairs cffort ;md that of the Corps expcnd("(1 the progress of the nood. during the fl ood of 1913. Section V AREAS FLOODED, FLOOD DAMAGES, AND FLOOD DAMAGES PREVENTED In the drainage basin of the Mississippi amounted to SI,154.770,ooO and $15,585,300,000, Rivcr. 16,71 1,500 acres were flooded. Areas respectively, resu lt ing in fl ood damage pre flooded with and without projects rAIlL£ 9 1>"~L\[J\RY O~ t\I!.fO\S 1t\·l Ti\' D.\TFD IIY 11.\1>[:-':". 197:1 FLOOD Acr~, Flu<~kd \\"ilh P"'l'""l> Acrt·, Flo.",I,,1 II'n),"\I! P'"i''''' Ii,,,;,, t ' ,Iw, C!ea, ~d ---11'""d",1 O Lhe, ",ban Ct,"",,1 It,,,,,,,hl O,hel 111'1"'" ,\I,,,,,. Iii I .92, ')(). !20 "PI" f{'\t., ti.tiOO 8 D.800 II ~.tiOU 25.:'100 1 <).UUO .280.100 ~Ii"'''m KiWI " ,ZOO " !2.',10 ". !20 1l7.170 7.!IIIO fi'lO. 100 (;.'l00 I 1'l.b90 11 1",ni, K,w, 18:", 1 !",'lO I , 'J 'l'l Z. '"0 1.'lOU 'IOi. !37 , I(U1 100 Ohio K i ye ' 2.:l',U 727.UOO ZO 1.900 0 3.50U %1. ' 00 21;9 ';00 0 A,'b",;,,; R"~r 8,710 !99.210 I08.',OU ti2.tiOO 27.·WO 1 .37 II, 2110 Ii II) , 7Z0 171.010 ~l. f , """i , Ki," " ,,0 1,,~ , ~00 253.b05 0 ~.1l50 , ',~1i. ',00 .327 ,', 1:, 0 \\"hi,~ K" c, 0 Zti'l,O()0 !l'l'l. 180 .900 IZO I'l l .'lOU ')'",. ~! .',(~I) ()""chil;o " '"" Rin" 3~() R29.1~0 , 176,970 0 23. ,"0 2 77 Rt~1 R,,,,·, 3.010 2 !II.JIIO 9~3,7"O 22.8()0 12.0()O :18~.OOO ,lUO iil.2',O \ ,,/0)(, K ;H' .130 . I 69.130 ,,!O 1'10 0 27.7:10 2 1115, 120 ,:n'1'" 220 0 B'g Black Ri,erand S\\" 'l"r,bui""n "0 ~9.860 152.j 10 0 IHI b2 1',0 2111i , ~;~O 0 .\I;o i 11 ~l<-m, ~I;"_,,ipp, KiH" 1,600 353.830 ,11I6.2S0 , 2.<)00 .~5:J.H:\U 1 Rli.231! , .-IIC h "Lo L"" R"e, ;00 2 1.000 707,UUO 51.000 11 ,Ot1O 7U.OUO 898.000 'J 1.1100 I '()"l~h"rt,."i" I"k,' 1. '",0 20.000 !ii~.OOO 1(;(; .000 117,000 112,000 ~;()" 0"" 6iH.OOO ~I ''';'''1>1'' ,II' har"Ia", ,ll't"" 2.:HlO ;,H,I)OO 7"1 ,000 1,2 I n.(j(jo 1.000 1<)1.(1(111 1175,1)111) I .~<)J .OUO (:.",,, 1 (It,,1 6.07'J,lii! H, 125,1:' I , 1 i I l~ti,2 II) 1',. !r,9 297 I:;,IH ~,O j~ ,OliO 31,'1% .no "" . :u, I AIILE 10 S l ' ~ nl ,\ RY OF ARE.o\S I",' I' NOA n : o 1:1, !OT,\ 1'1,.5. 1973 ~LOOD An..... Flood~"t! With Proj ...... s . \tT~." flood,,1 Without Pruj("C[s <'t:ll e I lri><1l1 CIe;m :d Wooded Oth", I I, h"" CI,·",.... I \\"ood,-cI Other i \rb ' h;'~ 9,,0 9!H .:165 2.611.,,1 " 28. 1:10 16.2;,0 l.6:'5./2.~ 6 535.:W" :'i .710 litlt1O;'I 3.03" 6 0 8.10~ 67.699 !J.IOO 16.110 1.2:'!J.037 !J i.IOO 20.620 I" diana 200 19-1.700 18.000 0 100 27'2.100 68.000 0 IU,,":I r.oo 6 5.250 10.'100 9 .200 800 177 , I ~O -11."3,, 611.090 K ;!I\sa~ 2.390 181.200 22.670 .U. 11O 9.3~0 146.670 1l3.',OO . 050 K,'nl11< ~) -100 J 77. 301 0 60.500 0 '00 ~ I I .1010 69 ..;00 " 0 1 ~'lI i,i ; ". " 7.320 9.H.770 3 .,,95 . 160 , 929.000 .~ 15,'190 3 . 360 . 130 -I . ;;23.420 2.;;40 .000 ,\ Ii "i.,il,!'i 2,ltiO I ..~3 1l .2 tiO .148.910 0 211.160 ,.016.840 .942.010 0 ~li~>OI1ti 8.0[00 91'12.37;, 241'1.1l00 II.U 10 12.180 1.513.175 733.01'10 12 7 ,11-10 Ohio 1.500 900 200 0 1.700 1.300 300 0 O~I"hom " 7 .190 286.330 86,880 38.600 20.110 799.100 2" 1.420 108.HO Te llll l'>"'-~ 2.'.00 272.100 198.900 0 II. BI.200 2 18.:)(JO 0 I,,,,:,, 50 59.530 325.420 11.:'90 1.050 100.91:10 567.400 3LHO \I'iyons. " 100 1-1.150 200 100 100 H. 150 200 100 lot:ol 31.-1% 6.079.6/-1 8. '125.-154 2. 1/1.970 -126.210 15.1:'9.297 15.1.14 .170 3.0 11'1.000 56 KY TENN , I ,i ,I I SCALE or MILES , " ," LEGEND B LEVEE SYSTEM AREA f"LOODED WITH PROJECT AREA rLOOD£D W ITHOUT THE PROJECT -- ) J MEX I CO FLOOD OF 1973 LOWER M ISSISSIPPI VALLEY PLATE 12 rMH .t; II Sl L\I.\IARY 0 ... 1!.173 FLOOD !Mi\lAGE AND DAMA(;t}) PIU:. VEN n:o RY RAS!:-.J S 1),lInages ]),,,nalo:l'S 1),lIl1age' Willi [xisling \\"I!II<)U! I' le\'c l11~tl Proj,'("ls l'rojf.YIS hy I'rnjl... ls [l"sin '$I (5 , (S) " "1)('1 .\Ii~siss i ppi R neT H2.257.000 1.169.8 18 .000 1.12i .591.000 .\hs.solill Rlvel 30.903 .000 1:'15.:.00.000 101.90.1. 000 IlIm"'l. R"l1 12.463. 000 71.010.000 5IL~77 . 000 Ohio Ri"t' l $0 .i '19.000 95.95g.000 65,201.000 A,).. ... I,:!, R;"er 15.635.000 15:) ,791,000 140 ,156.000 SI . I'bll(is R;\ ',~r S2.980,OOO 7~ 1.589,000 6111.909,000 '[7.'111 7,000 H.870.000 211.311:S,000 OU:I,IIII" R iH'1 90.00:',000 2,586.5/16.000 2.496.:'111,000 Rt ~ 1 Ril ci 25.712,000 35,062.000 9.~19.000 Ya/O() R,,'," 169.":'2.000 2.005.851.000 1.836."02.000 ll .g RI :ld: R" l'T :lnd S\\" rribul;lTies :;.6 16.000 ~i ,32 0 ,00 0 671,000 M,lin Slcrn·:>. lississippi Ril'n 239 ,6 79.000 101.5 19.000 -1 35. 159.000 " Allh.lf.l!a)" RII'CI 60,517,000 10.'I ,752,00U 15.20:',000 P,ml. lia'll',,;n I ~ ,k" 7,129 .000 6. 118,760.000 6. '" 631,000 :>. li .si.s;pp;· Aldt:,falay" ,\rea 111. 300.000 1,81B,698.000 1.800,3911.000 C ocod ri(- · Rond· TechI" VClm11 ion 5.i94.000 120.H2.000 11 '1.. "58 .000 rm. ,1 1.1 5 ". 77 0.000 15 .610.'[93.000 H.185,723.000 rhi~ hasi n includes lilt' unprOICCI('l! ",..:as !x,lween Ihe lel'tts or h"'lw",'" Ihe It-I·t't' and Iht opposite bank hills, where grcalc]' damages wc]'t SIl 58 T ABU:. 12 S l ' MMAR Y OF 1973 fLOOD DAMACES AN]) ])AMAGt:.... PREVE/<\rEU BY STATES Ihm :!K~'S lhrn"ges I),ullage>. Wi ~h t.SiSlIllg \\'ilho1l1 P re"~I11<:"(1 I'l flj.n, 1' lOjt"Cb by Projt"Cb SI,II" Basin IS) IS) IS) :\(kan!>;!. t\{kanr.a. Rivel 6,710,000 98,5HOOO 91.8-11.000 i\lai ... Sle",- :" 1i s.i.sippi Ri"el 21.301.000 18,677.000 _2,62·I.OOO a Ouaehila Ri" el 15.002,000 '128.6[01,000 " 12.7'19,000 Ret.! Rivn 1.883.000 ", 1· I'I.O()() 2.266.000 S,. Francis Ri" el 37.'171.000 5~7jOO.000 ,'>20.0:!'}. 000 While Rivcr ·]6,3 12.000 i~,551.ooo 27.239.000 T owl 129,579.000 1,181,0112.000 .05 J .50.~.000 low" Upper i\liHissippi R iHI' 12,72·1.000 83, 139,000 70:115,000 1>lissouri River 0 2,:,77.000 2,:'i7.000 Towl 12,721.000 30,~23.000 17,/99.000 Ill inoi~ Illil10is Ri'TT 12.463.000 7I,O'lO.!JOO "S,577.000 II PPl'1' M i ssissippi R j, I'r 2-12,177.000 I,007,i'l5.000 765,:.68.000 Ohio Rin'r 3,173.000 11,909,000 11,436.000 ,\J;, i 11 Slt!m 1\lissis.o;ippi Rhu 68.000 S,Of18.ooo 11,000.000 T Olal 258,1111.000 1,098,762.000 8'10 ..58 1.000 Indi ..... , Ohio Rin'r 5,8;:'6.000 7:168.000 1.612.000 T oml ::',856.000 7,·lf18.000 1.612.000 K:"",ls ,\rkansas Ri"cl 1.79.'U.1OO 11.827.000 13.032,000 :" l i~><)" T i Rin'T 2,382.000 2'1, 390.000 Tl,OOIl.OOO T Oial '1,177.000 .'S9,2 17,000 .'S5,O~O,OOO I ~ .. ,isi,"'a t\ lcharalaya Ri" I'r 60'::"17.000 10",7:'2.000 ':•. 20",000 1\1iss issippi-Alchaf" I.I} a Art';' 18,300.000 1,818,698,000 1,1100,398.000 Coeodric· Bocuf· T~,.. he· V,-,mil iOI1 :',79HIOO 120,3:'2.000 111.558,000 O uachila R iver 701,103.000 2, I:' 7 ,9.'1:"dlOO 2,083,1I~2,OOO Main S'ern-:\ I ississippi Rin:l' 1 16,2:>7,000 6,H3,OOO -13'j.82·I,OOO" R ,~I Rin'r 21.5:. 7,000 2~,877.000 2.320,000 Ponlchanrain LIke 6,SO'l.OOO 6, II II,H.~.OOO 6,111,6:1 1,000 Yaloo Ri" "r 3:)2.000 86 1,000 .~ O:l ,OOO TOlal 113S,il2,QOO I 0,3:,2 ..~oJ I.OQO l O.018,629,()O() ,\ Iinne'sm:. ( ' PlJel ,\ l issi,sippi R i I'l'r 2'12 ,O(JO 2,247,O()() 2,005,()()0 T Olal 2'J2. 0l)(J 2,247.000 2.005.000 ,\Ii""",.i Main 51e", :\ Iississippi Rin" i,080.000 7,080,000 0 1\ li,>O\I,.i Ri \'Cr 28,S2 I ,000 108.533,000 80.012,000 S, Francis Rin:' I:, ..~()<),OOO 177 .O8:l,OOO 161,,,110.000 L' ppo:r M ississippi Ri,,,,, 8I,O!),2.000 3f18,702,OOO 287.610.000 Whiu' Ri,u I. I 7:',(lOO 2 ..'H9,OOO 1.11-1.000 T ... "I 133.377.000 66.'S.72I1,OOO ".~O.3 · 16.OOO "I'nl'" k} Ohio River 6,5'19.000 38.6.'SJ,000 112.082.000 :\ I"i" Stt'lli' i\lissis,ippi Rin" 867,000 4'''211,000 3.6:'6.000 Towl 7, 116.000 1.'S, 153,OOO .'S:'.I.'S8.000 ((;011111111<:"(1 ) " rh;, I,,!sin includes thO' unprOlected ;.... ~as bl'lw~~n 1Ill' IC\l'('S or ht'lWl'Cll th~ !t\·Ct' ;md Ihl' Opposile bank hilh. ",here grmu:r dalllagf.'S Wl:U' SlI swi11t'l1 wilh Ill<' projl"C1 lh"" withou, ,h(., pmjcn dUl' to increds~d ri"el "ages resulling Irom confincn"'''1 of flows . .')9 TABLE 12 (Concluded) Damdgcs [),,,n"ge~ O,,",agcs With Ex is ti ng \\,ilhoul PIl'\'t'll led Projects I't OjLx-t' hy Projecl< IS' (S) lSI Rig l\l~c " R i'-~I and SW Triblll"ri,,~ '>.b·!6.000 (d20.000 674.000 a .\(a i" S t tlll - .\ (i s~issipp i Ri'Tr 51 .519.000 43.820.000 _ 7.729.000 I'ontchanrain LIke 327.000 .'S27.0{)O 0 Y,,,oo Ri"CI 169.100.000 2.00!,993.000 .835.893.000 Total 226.622.000 2.0'6.-IhO.OOO . R21l.1l~1l.0()() Ohio Ohi" River 8,317 .000 1:'.i80.000 7. ·j(;:S.O()() TOlal B.'1I7.0()() 1:'.780.000 7.lh3.()()(} O"lahom" Arbnsas Ri,w 7.1.10.0()() '!2.1 10.ooo 35.28().()OO Red R iver 189.000 .1.0()().()OO 2.51 1.000 7.619.000 '15.'110.000 :17 , /91. 0(}() Tl'nl1cs~t i\lain Stclll-1\lississippi Rivc] 12.5S/.()()() 1'>.911l .000 3.3G 1.000 Ohio Rin~l '1.6-12.000 17.:"196.000 12.9:>-1.000 T 01a l 17.19 Total 1.1113,000 - 1 . 0.~~ . O{)() 2,222.000 \\"C~I Virginia Ohio Ri" t'l 1.913,000 -1':lm.OOo 2,6:1/).000 TOlal 1.913 ,O()() -I.,>m,ooo 2.liS6.000 Upl"" .\ Ii s,is~ i ppi RiveT 6.023,O()() 8.015,000 1,992.000 TOlal li.02!I,OOO 8.01'1.000 1. Total .1'>'1.770,000 1:1.6'1O.'l93,O()() 14.4!!:> .723,000 a Thi, I""in i"du 60 Section VI COORDINATION WITH OTHER FEDERAL AGENCIES GENERAL Close coordination was maintained between agen c ies with which coordination was Corps officials alld several Federal agencies maintained and cooperative efforts werc throughout the emergency. The principal conducted are mentioned below. FEDERAL DISASTER ASSISTANCE ADM INISTRATION Disaster areas were established by Corps inspeclOrs were dispatched throughout the presidential declaration in the states of the damage areas to perfofm SUfveys as required. The iVlississippi River Basin that suffered major areas to be surveyed were: disaster damages. Under provisions of PI.. 606, :\ Ckar:tnCt: of delni> awl wreckagc; 91st Congress, Executive Order ]1575, and Tide H Elllcrgtncy protccti\"{" mcasurcs; 32 Code of Federal Regulations, Parts 1709 and C Repair Of rtptan''''''!l1 of "rt'·h. n""h. alUl high· 17 10, the Corps of Engineers is directed to provide w:') fadlilies; assistance to the affected areas when requested by [) Rq);.ir or rtptan''''''!l1 of dikes. h·,·,·{,s. irri!l,"alioll \\"01"'. ,md drain:,gc facilities; FDAA. This assistance consists of performing E Re pair or IcplacemttH of public buildings and I"{' inspections and making survey reports showing !:u{'(l equipmenl: and estimates of costs for clearance of debris from F Rep"ir or re~to";lIioll of publicl)' o\\",,,,d mili,;,'" public and private property, ami for repairs to public owned and maintained dikes. levees. O n rS of Engilleers facilities were required 10 irngation works, drainage facilities. etc.. that are allocate manpower 10 these surveys coincidental not eligible under P L 84-99 or other statutory with effons 10 repair damaged levees and other authorities. flood protection works. T he Onps performed a Upon receipt of a directive from FDAA. IOta I of 15.600 man-days work fOf FDAA. U. S. WEATH ER SERVICE The Corps of Engineers maintained weather predictions. These prediuions and COlltinuous contact with the U. S. Weather Scrvice forcGlsts were essential for planning the flood Bureau to obtam gage readings and stage and fight operations on a daY-lo-day basis. 61 U. S. CO AST GUARD As ~ tal t' d prcvioLisly, the Coast G uard activdy req uest. mon itored river traffic for excessive panicip:ut'(i a nd assisted in the O\uall flood speed s 10 p revent wa ve-wash damage to lev<'C (.'mcrgcncy cffo n th roug hou t the i\ liss iss ippi s}slcms. The Corps of EngintX' rs kep t the OxISI Ri \"{' 1" I ~a s i n . T he Coast Guard pcrforllu:1:. 1 man y Guard app rised of lock closings a nd open ings. valuabk se rvIces . such a s ('vacua t io n , Excel lent cooperatio n was main ta ined at a ll tra nsportation o f men and materia ls. emergency times . rescue opera ti ons. and . at Corps of Engineers 62 Section VII ANALYSIS, CONCLUSIONS, AND RECOMMENDATIONS OF THE MISSISSIPPI RIVER FLOOD PROTECTION SYSTEM TRIBUT AR Y BAS INS 111e Federal protection system in the red uced local fl ooding and the reservoirs tributa ry basin s p roved sound and effective. Local combined to lower the fl ood crest on the u pper and private works were less effective, with Mi ss iss ippi River at St. Louis, Mi ssouri, by 2 feet frequent failures. Man y of these failures resulted and the crest a t C."1iro, Illinois, on the lower fro m the levees or other structures being subjected Mi ss iss ippi River by more than 1.5 feet. The a r C MISSISSIPPI RIVER AN D TRIBUTARIES PROJECT GENERAL T he project flow line a nd hence the p roject levee grade had been es tablished based O il slage An ana lysis of the MR&T Project based on d ischarge rela tionships during the fl oods of 1945 the 1973 fl ood experience reveals many areas of and 1950, and the corresponding channel and concern of varying imponance. By far the most overbank cond itions. As Ihe 1973 flood develo ped importa nt single item of concern, and the one and prepara tio ns for a major flood continued , il demanding the most immediate attention was the becam e a ppa rent that the stage-discharge channel deterioration which was found to have relationship was several feet higher than the slage develo ped. T his problem and others highlighted dis('hnrgc rela tio nship upon which levee grades uy the flood are discussed in the following were based. Channel efficiency has diminished subparagraphs. thro ugho ut the lower Mississippi River due to chan ges arisi ng from the dynamic nature o f the CHANNEL DETERIORATION, a lluvial ri ver, the persistem tendency of the river PROJECT DESIGN FLOOD to meander, the insta bility introduced by the FLO W LINE AND LEVEE-RAISING cutoH p rogram, and a generall y incom p lete river stabili 7.a tio n program. These changes included Design Basis the formation of meanders, divided fl ows, and The MR&T Flood-Control Plan is designed sa n dbars, and havc occurred generally to contro l the Project Design Floodof3,030,OOOcfs th rougho u t the m iddle reach of the lower rive r. In al the latitudeof Old Ri ver. T he projcct !cn'es and developing the original Project Dcsign Flood fl oodwalls are des igned to confine the project Flow Line, the IX>ssibili ty of a dccrease in channel flood discharge based on a computed flow line. efficiency was considered, bu t no special 63 allowance was made for this loss. Facet! with the caused by the channel deterioration within banks. prospect of a flood reaching project flood For this reason, the net effect of the reduced proportions, an examination of flow lines was channel capacity diminishes as stages rise above conducted to determine the steps that would be bank-full. Utilizing these revised channel necessary to protect the Valley. characteristics, the lIlcrease III flow line attributable to channel deteriormion was Stage-Discharge Relationships computed. This computational approach was The Project Design Flood Flow Line had verified on the Mississippi Basin Model at been established using data from the 1945 and Clinton, Mississippi . The increasc of 4.5 feet in 1950 floods. Stage-discharge measurements made stage at Vicksburg obsen'ed at bank-full capacity during the 1973 flood showed that a serious translates by computationa l meLhods to be 2.8 feet reduction in channel capacity had taken place in at project rIood level. The increase in project flood the middle reach of the lower Mississippi River stage resulting from channel deterioration at si nce 1950. At the peak stage of the 1973 flood, other locations amounts to 1. 6 feet at Arkansas with the river approximately 10 feet above bank City, 2.3 feet at Natchez, and 2.3 feet at Red River full stage, o bservations indicated that the capacny Landing. These resuiting stages were then of the river was about 1.5 percent (350,000 ds) less increased by an a llO\vance toaccou nt for the loop than the capacity under 1950 channel conditions. effect as described in the next paragraph. At Vicksburg, this amounts to a shift of 4.7 feet Loop-Effect wilh 1.5 fWI attributable to loop effect (discussed later) and with the remaining 3.2 feel attributable Some increase in stage during the 1973 flood to channel deterioration. A similar pallern of was attributable to the loop-effect observed in sh ifts was observed at other gaging stations a long stagc-discharge relationsh ips. It is a phenomenon the middle reaches o f the lower Mississippi River. of river flow hydrauliCS that a rising river will pass The two main causes of these shifts, channel a given discharge at a lower stage than a falling deterioration and loop effect, are discussed in river. When the recession of the first flood peak IS subsequent paragraphs. fo llowed with a secondary rise before the loop has closed back onto itself, the new rising rating curve Channel Deterioration is stepped upward producing higher stages for a To determine the effect of channel given discharge. Some floods, like those in 1937 deterioration on the stage for the Project Design and 1950, had a fairly smooth rise and fa ll. In Flood d ischarge, it was necessary to develop a contrast, the 1973 flood was a long flood, in which method to extrapolate from observed data to high stages were sustained over a period of higher flows. Because of the unreliable nature of months, with successive crests, parti 64 curve had been lISl.'ti in establishing the Projeci Summary of Mississippi River Des ign Flood Flow Line. It is now evident, in a Adjusted Flow Line valley sLlch as the Mississippi where the Ik'GlllSe of til(' loss of channel capacity to dale consequences o f levee overtoppin g are and the need to prolect against such factors as lInacceptable, Ihal Ihe use o f an average rolli ng loop·effect and a minimum level of future cll rvc is unacceplable. Protection must bc based deterioration, tilt' p roject flood flow line and on the most severe case reasonably expectt.-u to corresponding le\'('(' heights will requIre OCC llr, In corn"cting this situation. o thcr substarllial raising in the middle reach of the i\ liss issippi River floods exhibi ting a multiple lower i\lississ ippi River. A comparison of the loop·dfect were analYLed 10 arrive at a reasonable 1973 Adjustcd and the origmal Project O<:sign va lue 10 add to Ihe Project Design Flood Flow Flood Flow Lines for key stations on the lower Line, as corrected for channel deterioration. As a :\ Iiss iss ippi Ri ver is given in Table 13. resul t. at the projeci flood discharge, the followi llg stage increases for loop·effect were added to the stagc increases for channel deterioration: 2.'1 feel Atchafa laya Rasin Floodway Adjusted Flow Line al Arkansas Cit y, 1. 7 feel at Vicksburg. 1,7 fcel al NalchcJ., 1.7 fcct at Red River Lmding. and The situatio n in the Atchafala),a Flood\\'ay 1.0 foot al BalOn Rouge. somewhal parallels that in the "-lississlppi. The flood way is bounded by the E;ISt and WeM Guide Future Channel Deterioration Levees to conlain fl ood fl ows passed down the I")re\'io us flow· line calculat io ns had Atdlafalara Basi n. The reqUIred discharge considef('(l that the cha nnel in the middle reach through the Alchafalaya FI{)()(] way during design would attain equilibrium under conditions flood conditions fo r the !\ IR&T Project is exisling in the 19·15·50 period. This assumptio n 1.500,000 cfs. Guide levees ill conjunction wi th a has proven to be erroneous. The rilte al which the central challnel Ihrough the floodway are chanuel stabili zat ion program was pursued did designed to confine this design fk)()(1. Without not keep pace wi th river developments, with the such floodwilY capacity in the AtLhafalaya, the result thai some o f the gains of the cutoff Ul('an s for handling floods approaching projeci program of the thirties were lost. Some dimensions in llle Lower Mississippi Valley 65 TABLE 13 ORIGl.""!. AND ,\DJ[ ISTEIl FLOW U:'IES Origin,,1 'i l Adjuw:.. 1 Flow Linl' How Li.ll' Ch.Itl)o:l· Locati on IN'1 [cr. It'<.' l "'Ihoon Landin~ . '\lk:lr"", 213.3 Z!B 0 I kim .•. ,\rkan ... r. 201.3 2Q4.8 10.:' . \rL,n ~a ~ Cil ~ . ,'rk.,,, ~ ,, s 1:.1.1 1:"0 8.6 t 1.5 ,'i, l,h"rg. L\ 1 " ~lSs lppi 10:'. ] 110.9 ·5. ~ i'>;tt< h'·I. :\ ] i .", ~ ~ippi "'.0 8 · L~ +1.5 R"d Rln'z LUldj'I~. ] AlI .. i.i""" 61.0 t>5.0 • 1.0 1I.1\"n R ou~ c . I.o"i,i""" 16.01 '17.'1 >1 .0 j)()!LII,holl' i lit-. I .n " 1si" "" 33.6 .B.6 0 Cil),. Studics arc under way todctcrmine measures amounts in the affecII..'d reaches to provide this that will relieve 1hi s si tuation. Substantial data 0 11 protectiOlI. currcn] Alchafalaya Basi n rlow characleristics Alternalive 5olulion5 were obtained during the 1973 flood. pcnnilting a r('C\,.. duation of the projt."Ct flood flow line. This To Ino[('CI the illle~,'T it y of the levee S),S lem , rccvaluation was vcrified in the model using the considering the adjusted flow line, a number of 1973 flood stage-discharge observatio ns. and alternati ve solulions were examined, all of which model nllls were Ill;H..lc for the project flood have been studied in some detail. It was considered condi tions. Bascd on ]hesc model runs, the project essential that the scJect« \ solution be immediately rI(Xx.i flow line was adjustl'd2 to 4 feet. depending pursuable, adequale to provide s(."CuriIY 10 the on location. Valley, and accomplishable within a reasona bl e lime frame and 66 Ai ternalivt.'S Considered carrying capacity of the Mississi p pi River in the Storlllg Excess Floodwater ill AdditiOllaf affec ted reach could be increased by reduci ng the Uesrrvoir,f-Considcra tio n was g ive n 10 loweri ng prcsen l chanllel lcngth. In vestiga tio ns indicdte 1'1 ti l<' fl ow lille by provid ing additiona l reservoirs IOGllio ns h'here successful cutoffs wo u ld sho n en wit h ;l combined storage capacity sufficient to the river a pproximately 78 m iles in the reach reduce st ages as necessa ry to conform to the i>C tw('C n I Jelena. Arkansas. and Baton Ro uge, orig ina l I>roject Design Flood Flow Li ne, Louisiana. Based o n expenences w ith the J.owering the discharge to sta y w ithin the 1973 p re"io us CUlOffs. an allowance of 25 miles has Adjusted Project Des ig n Flood Flo w Line wo u ld been made fo r length regain l..'Ci before alignment require 27 m illion acre-k'C t of fl OCKI- control co ntro l could be ach ieved . The net reduction in Slornge_ For one combination of storms, a total o f ri ver length for the cu toffs co n sidered wo uld 69 reservoirs wo u ld be required to provide the lo wer the adj usted flow line a pproxima tely 3 feet. requi red sto rag"e_ Fifty-six o f these could he T he estimated COS t of the cutoffs including h eadwater reservoirs III the Ohio, Upper relocat io ns a nd channel improvements would ue ;\·Iiss issippi, and Missouri River Basins. One 1.'1 bi ll io n do llars. T his eSTimate is based on the coul d be ;l Illa in stem reservo ir about 7 miles assumptio n that a ll these cutoffs would develop u pstream of e lpc G irardeau. Missouri. T welvc satisfactoril y ill to the main river channel. Sillce could Ix' headwater reservoirs on tributari l..'S to the the 3-foot lowering in the flow line would not be m;lin stem betwccn C "l iro. lliinois_ and Arkansas adeq uate, the cutoffs wou ld have to be combined City_ Arkan 5<'lS. To a llow for other comhinaTio lls wi th o tl1('r m f'a~ 1In '" "1I ch a ~ challlwi rln>fleine . of s torrn~ Ihat co uld produce the p roject design add itio na l fl ood ways, or hig her levees. The fl ood , mall)' mo re resen"o irs wo u ld be requ ired. Alchafa laya Ri ver is a relal i\'ely stra ig h t ri\'cr; 111e I"f.'qu ired acre-fcct of storage in the man)' therefore. sites for cutoffs to lower Th e fl ow li ne in reservoirs that lll ust be provided wou ld han' to be till' At chafa la ya Hasin are not available. The least alloca ted exclusivel y for fl ood·control benefits in costl y comhinatio n under th is a lternative would the Lower i\lississippi Ri ver Valley. The he the 1'1 cu toffs combined with le\·I..'t' raising a t a operation ami maintenance of th is large nmnuer lo tal l'stima ted cost o f 1.8 billion dollars. o f reservo irs 10 achieve the desired m:luClio n in the D ivertillg Flood Flows-An addi tional fl ow lim' would bc extremely complicated and noodway 10 divert Mi ss iss ipp i River fl OCKlwaters expe nsive in terms of man power and funds. ami adl'tpta lcl y lower th e Adj usted Project Des ign I II CrC(lSi ll g the l-I ydraulzc CafJacilY of the Flo(xl Flow I j ne was also considered. The H i vl'r by D redglllg-The practicahil ity of d i\"Crs io n of flow wou ld be required at abou t the lowering the Project Design Flood Flow Line o n la tilllde o f Al"k;I nsas City, Arkansas. to reduce Ihe i\ liss iss ip p i and Atcha fa laya R ivers by stages in the a ffected reach. T he fl oodway wo u ld channel dred g ing beYOI\d that presen llyem lxxlied be located ill the Bocuf Basin , roughly following III the ado pted p lan was <-·o nsidered. T h is thl' Bocllf River, and em ptying illlo the lower Red a lternati\"(' would d isturb the equ ilibrium of the Ri ver. A control structure would be required w ith rivers, adversely affect na \·igation . and create a fl ood way ;:l\"crag ing 7.5 mi les w ide and 150 m iles 11U IllerOItS unpred iclab le problems, making th is long \\'ith g uitie levccs. Extensive relocatio ns a lte rnati\'(' q lH.'S tio nable from an eng ineering wou ld be necessary because o f the man )' feasibilit}' sta ndpoi nt. The estimatl..'Ci cost wou ld h igh wa ys . ra ilroads. dminage canals. utili ties he in excess o f 3.5 bill io n dollars. servici ng the well -populated area, and numerous I lI crrasmg the H ydraulic CaIJa cit), of tlte hOIl1<.'s and businesses in the fl oodway. This H lVer w itlt Add iliOlwl Cutoffs-The fl ood - fl OCKlwa}' was stud ied ill greaT deta il in the 1920's 67 and was subsequently rejected as be ing COrlcfuSIOIIS-The lower Mississippi River is unacn:ptable (ltlt! abandom:d by Committee a dynamic hydraulic system being changed by con Document No. I. 74th Congress. 1st Session. 1935. tinuing phys ical processes. Since 1948 a trend of It would be cvcn less acceptable today. decreasing chanilel capacity has been noted for To .~uppleme nt thc existing floodway smal l 10 moderate floods. but these lesser flows did capacit y of the Atchafalaya Basin, an additional llot provide the data ne<.- 68 proper procedure to secure additional protection Improvement. Until the main-line levees are all where justified. brought up to grade and section and the main river channel is more effectively stabilized, the FUSEPLUG LEVEES lower Valley will continue to be subject to devastation, and periodic emergency measures Backwater areas, partially protected by can be expected to recur. fuseplug levees which wi ll be ovcrtopped before It is recommended that completion of the the project flood crest arrives, are an integral part authorized flood-control projects be expedited by of the MR&T Flood Control Plan. Theoretically, funding the project to the full capability of the the storage capacities of these areas are needed to Corps of Engineers. enable the main-line levees to contain the project flood. When the flood-control project was SEEPAGE conceived, most of these areas were relatively uninhabited and undeveloped. Since then, an Seepage is one of the oldest and most familiar influx of people and improvements has taken flood problems which intensifies with increased place. Allowing these areas to be "sacrificed" in duration and height of the flood. Underseepage is the interest of the remainder of the Valley will the most widespread, but through seepage does meet with strong resistance and isa real problem. exist particularly with sandy levees and for floods Elimination of fuseplug levees is desirable of long duration. There are standard means of but cannot be done withoUl making other treating levee slope seepagt' and boils which are compensating changes in the flood-control plan. intended to maintain the integrity of the levee. It is recommended that ways to achievc these It is concluded that seepage comrol measures compensating changes be studied. should continue to be constructed where required to safeguard the levee system. OLD RIVER LOW-SILL CONTROL STRUCTURE PUMPING The loss of a training wall on this structure during the 1973 flood and the subsequent Throughout the basin there are many areas scouring that occurred jeopardized the integrityof protected from headwater and backwater flooding the struClure through the flood period, and which rely on gravity drainage structures as because of its critical importance also jeopardized interior drainage outlets. During floods these the integrity of the MR&T Projec t. structures are closed and the imJhlundments of Emergency repairs have heen made and seepage and rainwater often cause interior slUdies are presently under way to determine the flooding of serious proportions. In some cases, stability and adequacy of the structure. pumping stations are authorized which will solve the problem. Studies should be made which will EARLY COMPLETION OF include the additional cost of emergency THE MR&T PROJECT pumping during times of flood. The MR&T Flood Control Project has been Care should be exercised to insure that under construction for well over 40 years. Some submarginal lands are not protected by pumping, essential major elements of the project are still I.e. the sump area. Floodplain management incomplete, I.e., L ev~es and Channel should consider restricting the development of 69 submarginal lands (sump areas) requiring encouraged and that consideration be given to protection. conslruCling levee slope protection in the most critical areas. PIPES THROUGH AND UNDER LEVEES Experience during the 1973 flood and CHANNEL DETERIORATION previous floods has shown that pipes and culverts ON TRIBUTARY STREAMS through or under levees are definitely poten Data collected during the flO 70 fight. Stone was in short supply in some areas AFTER-ACTION CONFERENCE because of quarry locations and transportation problems. TIle 1973 Adjusted Project Flood Flow Line It is recommended thaLstone stockpiles, ifnot analysis impacts heavily on Federal and nOIl already committed, be established at critical Federal investrnems for flood proteClion. locations. Therefore, it was decided to approach some of the best qualified hydraulic engineers a nd MAINTENANCE SUPPORT potamologists in engineering practice and the FOR ARMY VEHICLES academic field to acquaint them with the problem of changing flow lines in the unstable Mississippi Several Districts were able to obtain vehicles River and to solicit their views and from Army un its adequate 10 meet their needs. recommendations. On II April1974,aconference However, they all reported that a problem existed was held with Dr. VitO A. Vanoni, California in maintaining these vehicles since parts were not Institute of Technology; Dr. Daryl B. Simons, readi I y a va ilable commercially. Emergency University of Colorado; Dr. Alvin Anderson, St. operations performed subsequent to the 1973 Anthony Falls Laboratory, University of flood have demonstrated thal a request for Minnesota; the Committee on Channel veh icles should include maimenance capability. Stabilization; and representatives from HEC, This procedure has worked very well. DCE, WES, and Missouri River Division in It is recommended that advanct' arrange attendance. The consensus of the conferees was men ts be made for securing necessary parts that the analysis as presented was reasonable and a nd maintenance expertise as needed for Army adequately conducted and that further and more vehicles borrowed during times of emergency. detailed studies should be undertaken to refine certain areas of the analys is of the flow line. These BETTER MA INTENANCE OF ALL FLOOD PROTECTION WORKS studies have been formulated and are being conducted. The conferees were also requested to Every flood clearly demonstrates the make recommendations relative to direction for importance o f proper maintenance, whether it be ongOlllg and future potamolo!,'1', channel by Corps of Engineers or local interests, of all improvemem, and hydraulic studies to arrive at a flood-control structures. The 1973 flood was no solution to prevent or minimize future losses in exception. channel capacity. A polamology program and It is recommended that emp hasis on the plan of study have been formulated and initiated, Importance o f proper maintenance of all f1ood incorporating the recommendations of the control Slfuctures be increased. conferees. 71 Printed aT The U. S. Army Enginee r Waterways Experiment Station Vicksburg. M iss issipp i 39180