EvolutionEvolution ofof thethe LeveeLevee SystemSystem AlongAlong thethe LowerLower MississippiMississippi RiverRiver J.J. DavidDavid Rogers,Rogers, Ph.D.,Ph.D., P.E.,P.E., R.G.R.G. NaturalNatural HazardsHazards MitigationMitigation InstituteInstitute DepartmentDepartment ofof GeologicalGeological EngineeringEngineering UniversityUniversity ofof MissouriMissouri--RollaRolla ...Ten...Ten thousandthousand RiverRiver Commissions...cannotCommissions...cannot tametame thatthat lawlesslawless stream...cannotstream...cannot saysay toto it,it, "Go"Go here,"here," oror "Go"Go there,"there," andand makemake itit obey.obey. -- MarkMark TwainTwain INTRODUCTIONINTRODUCTION TheThe leveelevee systemsystem hashas beenbeen presentpresent alongalong thethe MississippiMississippi RiverRiver sincesince thethe firstfirst EuropeansEuropeans settledsettled thethe region,region, butbut itsits designdesign hashas changedchanged manymany timestimes sincesince thatthat firstfirst levee.levee. TheThe changeschanges werewere broughtbrought aboutabout mainlymainly byby flooding,flooding, whichwhich inin turnturn drovedrove otherother factorsfactors suchsuch asas costscosts andand politics.politics. TechnologyTechnology hashas alsoalso playedplayed aa rolerole inin thisthis development.development. LEVEESLEVEES Earthen embankments built on the natural levees parallel to the river channel and designed to protect the area behind it from high flows in the main channel Levees must be high enough to prevent overtopping and broad enough to resist deterioration from hydraulic piping OVERTOPPINGOVERTOPPING Levees are often overtopped where they have experienced differential settlement; generally where underlain by soft soils, such as old oxbow fills or peaty bulrush marsh deposits. CREVASSECREVASSE isis thethe termterm appliedapplied toto breaksbreaks wherewhere underseepageunderseepage hashas causedcaused thethe leveelevee toto collapsecollapse SCOUR Scour from local eddified flow often occurs at steep drops, around, or over flow obstructions, as shown here. MississippiMississippi RiverRiver DrainageDrainage BasinBasin TheThe MississippiMississippi RiverRiver drainsdrains 4141 percentpercent ofof thethe continentalcontinental UnitedUnited States,States, stretchingstretching fromfrom MontanaMontana andand CanadaCanada toto westernwestern NewNew York.York. TheThe basinbasin coverscovers moremore thanthan 1,245,0001,245,000 squaresquare miles,miles, includesincludes allall oror partsparts ofof 3131 statesstates andand twotwo CanadianCanadian provincesprovinces Areas subject to flooding along the Lower Mississippi shown in pink YouYou hardlyhardly everever seesee thethe river,river, butbut thethe leveelevee isis alwaysalways closeclose by,by, aa greatgreat greengreen serpentserpent runningrunning throughthrough woods,woods, swamps,swamps, andand farms,farms, withwith townstowns nestlingnestling closeclose toto itsits slopes.slopes. TheThe leveelevee isis unobtrusive,unobtrusive, sincesince itsits slopeslope isis greengreen andand gradual,gradual, butbut inin factfact itit isis immenseimmense ---- higherhigher andand longerlonger thanthan thethe GreatGreat WallWall ofof China,China, veryvery likelylikely thethe biggestbiggest thingthing thatthat manman hashas everever made....Itmade....It waswas thethe principalprincipal humanhuman responseresponse toto thethe titanictitanic powerpower ofof thethe greatgreat river.river. ---- AlanAlan Lomax,Lomax, TheThe LandLand WhereWhere thethe BluesBlues BeganBegan FIRSTFIRST MANMAN--MADEMADE LEVEELEVEE LeveeLevee constructionconstruction beganbegan withwith thethe firstfirst settlerssettlers alongalong thethe MississippiMississippi RiverRiver BetweenBetween 17181718--2727 aa leveelevee waswas builtbuilt aroundaround NewNew OrleansOrleans modelingmodeling thosethose inin FranceFrance It was 5400 ft long ,18 ft wide at the crown with a roadway 4 ft high, and had a slope of 1:2 EARLYEARLY LEVEELEVEE CONSTRUCTIONCONSTRUCTION StateState governmentsgovernments mademade itit policypolicy thatthat farmersfarmers builtbuilt theirtheir ownown leveeslevees alongalong thethe areasareas theythey ownedowned alongalong thethe MississippiMississippi RiverRiver HaulHaul methodsmethods wouldwould yieldyield 1010--1212 cubiccubic ydsyds perper dayday withwith aa haulhaul limitlimit ofof 7575 feetfeet EARLYEARLY LEVEELEVEE CONSTRUCTIONCONSTRUCTION Trapezoidal Levee URBANURBAN LEVEESLEVEES Levee construction at New Orleans in 1863, during the Civil War. RAISINGRAISING LEVEESLEVEES The levees along the lower Mississippi had to be heightened continuously between 1850 and 1927 because the bed of the Mississippi River elevated itself, because of increased confinement, caused by levee construction. EarlyEarly FederalFederal LegislationLegislation In 1820 the first Federal Government involvement along the Mississippi River focused on navigation, not flood control Disastrous floods along the lower Mississippi and its tributaries in 1844, 1849, and 1850 resulted in the Swamp Acts of 1849-1850 SwampSwamp ActsActs ofof 18491849--18501850 First federal involvement for flood StateState LandLand GivenGiven control along the (sq.(sq. mi.)mi.) Mississippi River IllinoisIllinois 2,2772,277 First Act gave Louisiana all swamp MissouriMissouri 5,2305,230 and overflow lands within its boundaries ArkansasArkansas 12,01012,010 that were unfit for cultivation MississippiMississippi 5,1415,141 Second Act did the same for Arkansas, Missouri, Illinois, and LouisianaLouisiana 14,74014,740 Mississippi SwampSwamp ActsActs ofof 18491849--18501850 The lands were to be sold to the public and the money generated to be used to construct levees and drainage for the reclamation of the lands Lack of coordination between states and levee districts resulted in the levee lines being a failure State Levee Design Criteria Louisiana Crown 1/3 of base Side slope 1:2 Arkansas Height = 30” above overflow Crown width = height Base width = 7 x height Mississippi Side slope 1:6 on riverside 1:2.5 on landside LeveesLevees areare anan inherentinherent liabilityliability 18501850 MississippiMississippi RiverRiver SurveysSurveys In 1850 Congress appropriated $50,000 to conduct two hydrographic and topographic surveys of the Mississippi River; one by a civilian and the other by a civilian One survey was conducted by Army Engineers A. A. Humphreys and Henry L. Abbot, but was not completed till 1861 Civilian engineer Charles Ellet Jr. was also authorized to prepare an independent survey, completed in 1852 The Humphreys-Abbot report considered three methods of flood protection: Cutting off bends in the river Diversion of tributaries and creating artificial reservoirs and outlets Confining the river to its channel (the levee system) The conclusion was that the first two options were too costly and provided little advantage, thus the third option was recommended Their levee design called for freeboards 3- 11 feet above the 1858 flood DETERIORATIONDETERIORATION ofof LEVEESLEVEES The Civil War left the levees along the river in disrepair, exacerbated by severe floods in 1862 and 1865 The 1867 flood caused an additional $3.9 million of damage to the levees, estimated that 9.75 million cu. yd. of fill would be needed to repair the levees 1874 flood resulted in the creation of a “Levee Commission” to survey the system and submit a plan for reclamation of the Alluvial Valley The most cited failure modes for levees include underseepage, hydraulic piping, and overtopping. In actuality, excessive uplifting seepage on the landside toe probably triggers mass liquefaction, which triggers extensive bearing capacity failure, which then causes a catastrophic slope failure. In this manner, 100 to 2000 lineal feet of levee can collapse in a few seconds; which is the usual pattern. MISSISSIPPIMISSISSIPPI LEVEELEVEE COMMISSIONCOMMISSION EstimatedEstimated itit wouldwould taketake $3.5$3.5 millionmillion (8(8 millionmillion cu.cu. yd.yd. ofof fill)fill) toto repairrepair thethe leveeslevees ItIt wouldwould taketake $46$46 millionmillion (115(115 millionmillion cu.cu. yd.yd. ofof fill)fill) toto buildbuild thethe entireentire leveelevee systemsystem DeterminedDetermined 55 defectsdefects inin thethe leveelevee system:system: ViciousVicious leveelevee organizationorganization InsufficientInsufficient leveelevee heightheight InjudiciousInjudicious crosscross--sectionsection andand constructionconstruction InadequateInadequate inspectioninspection andand guardingguarding FaultyFaulty locationslocations StSt LouisLouis Levee,Levee, 18671867 MISSISSIPPIMISSISSIPPI RIVERRIVER COMMISSIONCOMMISSION--18791879 The Mississippi River Commission was created by an Act of Congress in 1879 GenerGeneralal Humphreys argued against the MRC covering flood control, because he thought the Corps of Engineers should control the river Others argued that flood control should be a state issue Flood control was looked at as an integral part of river navigation According to the MRC, the greatest detriment to levees was river instability and bank caving CompositionComposition ofof thethe MississippiMississippi RiverRiver CommissionCommission (MRC)(MRC) Legislation pushed by James B. Eads 7 members appointed by the President 3 officers from Corps of Engineers; one of whom serves as chair and another as secretary 3 civilians (at least 2 civil engineers) 1 US Coast and Geodetic Survey (now NOAA) Brevet Major General Quincy A. Gillmore MississippiMississippi RiverRiver CommissionCommission (MRC)(MRC) The