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August 2003 Number 23 W ATER MARKS W ATER MARKS Louisiana Coastal Wetlands Planning, Protection and Restoration News Louisiana Coastal Wetlands Planning, Protection and Restoration News www.lacoast.gov www.lacoast.gov FRESHWATER DIVERSIONS: Revitalizing Louisiana’s Coastal Wetlands FRESHWATER DIVERSIONS: Revitalizing Louisiana’s Coastal Wetlands

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August 2003 Number 23

WATERMARKSWATERMARKSLouisiana Coastal Wetlands Planning, Protection and Restoration NewsLouisiana Coastal Wetlands Planning, Protection and Restoration News

www.lacoast.govwww.lacoast.gov

FRESHWATER DIVERSIONS:Revitalizing Louisiana’sCoastal Wetlands

FRESHWATER DIVERSIONS:Revitalizing Louisiana’sCoastal Wetlands

August 2003 Number 23

Please address all questions, comments,suggestions and changes of address to:

James D. AddisonWaterMarks EditorNew Orleans DistrictU.S. Army Corps of EngineersP.O. Box 60267New Orleans, LA 70160-0267(504) 862-2201E-mail: [email protected]

WaterMarks is published quarterlyby the Louisiana Coastal WetlandsConservation and Restoration TaskForce to communicate news andissues of interest related to theCoastal Wetlands Planning,Protection and Restoration Actof 1990. This legislation fundswetlands enhancement projectsnationwide, designatingapproximately $50 millionannually for work in Louisiana.The state contributes 15 percentof the cost of project construction.

For more information about Louisiana’s coastal wetlands and theefforts planned and under way to ensure their survival, checkout these sites on the World Wide Web:

www.lacoast.gov www.americaswetland.comwww.btnep.org www.crcl.org

Correction: In the graph on page 9 of WaterMarks Number 22, the projec-tions for precipitation by the Hadley and Canadian climate models werereversed. We apologize for this error.

ABOUT THIS ISSUE’S COVER . . .Traditionally used to enhance oyster yields,freshwater diversions today are an essential toolfor sustaining and restoring Louisiana’s coastalwetlands.

Photograph, “Tonging Oysters, 1938” used by permission ofMeriget W. Turner, curator, Fonville Winans Collection

Photograph of oyster shells by Rex Caffey,Louisiana State University Agricultural Center

SubscribeTo receive WaterMarks, e-mail [email protected]

For current meetings, events, and other newsconcerning Louisiana’s coastal wetlands, subscribe to

the Breaux Act Newsflash, our e-mail newsletter, at:

www.lacoast.gov/newsletter.htm

August 2003 Number 23

3 Restoring the Natural Flow:Diversions Rebuild Wetlands

5 Diversions:Routing Water into Wetlands

7 Diversion Critics Question Impacton Economy, Environment

10 Diversions Build Hope for Wetlands

12 WaterMarks Interview:Mark Schexnayder

WATERMARKSLouisiana Coastal Wetlands Planning, Protection and Restoration News

WATERMARKS August 2003 Number 23

3

WATERMARKS August 2003 Number 23

SWOLLEN WITH watersdrained from nearly half of thecontinental United States, theMississippi River in flood stageembodies the terrifying anddestructive force of nature. Inits wake it can leave a trail ofdevastated fields, uprootedtrees and ruined buildings.

To protect human life andproperty from the ravages offlood, a 1,600-mile system oflevees and control structuresnow constrains the river andfunnels its muddy waters intothe Gulf of Mexico. But, whileshielding cities and industryfrom disaster, these barriers ofearth and concrete are starvingthe wetlands to death. Deprivedof the floodwaters’ rejuvenating

Restoring the Natural Flow:Diversions Rebuild Wetlands

nutrients and sediment, thecoastal wetlands cannot combatthe degrading effects of subsid-ence and saltwater intrusionand are vanishing. To restorethe benefits of flooding withoutthe risks of flood, wetlandproponents advocate the strate-gic breaching of the levees,allowing river water to flow intoselected marshes and bays. Thehopes and challenges associatedwith this powerful techniqueare the subject of this issue ofWatermarks: RevitalizingLouisiana’s Coastal Wetlands.

River Water BuildsCoastal LandsFor eons the Mississippi Riverhas shaped the coast of Louisi-

ana through cycles of growthand decline. Jumping its natu-ral banks and engulfing thedelta, the river pushes backsaline water driven toward landby wind and tide while deposit-ing nutrients and sedimentcollected from upstream.Particle by particle, the sedi-ment settles into the alluvialsoil of bayous, swamps andmarshes. Plants, nourished byriver water, take root, trapmore sediment, die and decayto create a biomass that trapsyet more sediment. Incremen-tally, wetlands emerge, support-ing marsh vegetation, providinghabitat for fish and wildlife, andbuffering the coast from stormsurge and sea. As land accretes,the river inevitably seeks ashorter route to the Gulf,eventually carving out a newchannel and abandoning the oldwetlands. Deprived of an influxof nutrients and sediment,wetlands sink, succumb to saltwater and disappear.

Though today’s levees andcontrol structures successfullyrestrain floods, they alsointerrupt the age-old process ofwetlands formation. TheMississippi, constrained withinits banks, is forced to carry its

Courtesy of David

Seawell

Fresh water flooding into the marshes delivers nutrients and sedimentvital to a thriving wetlands ecology.

WATERMARKS August 2003 Number 23WATERMARKS August 2003 Number 23

4

21 3 4

5 6

WATER MARKS

load of land-building sedimentinto the Gulf of Mexico, whereit tumbles to the ocean floorand lies useless for restoringland. Without the rejuvenatingsediment and nutrients of theriver, existing wetlands decline.No new wetlands emerge. Saltwater, advancing rapidlythrough navigation channelsand pipeline canals, invades theestuaries. Vegetation recedes,marshes erode into the ocean,and coastal Louisiana vanishesat the rate of one acre every35 minutes.

Reclaiming Benefits byMimicking NatureThe best antidote for thedecline of Louisiana wetlandsmay lie within the MississippiRiver itself. Purposeful breach-ing of the levees, known asdiversions or river reintroduc-tions, can mimic the naturaloverflow of the river, routingfresh water, nutrients andsediments into marshes tonourish vegetation and todeposit the material needed tobuild emergent land.

Although diversions differ in

construction and scale, theprimary goals of all diversionsare to supply marsh-buildingingredients and to alter thesaline content of the outflowarea, boosting critical plantgrowth and providing a healthyhabitat for fish and wildlife.

Expanded Purpose for anOld PracticeThe first levees along theMississippi River were built inthe early 18th century. In the1830s the first intentionalbreaching to enhance oyster

yields was recorded, and diver-sions to irrigate crops andstimulate fish productionbecame common. The idea ofusing diversions to restorewetlands emerged over half acentury ago, and is now aleading strategy as agenciesaffiliated with the CoastalWetlands Planning, Protectionand Restoration Act recognizethe Mississippi River as theirmost powerful ally in combatingthe current crisis of Louisiana’scoastal land loss.

Courtesy of NO

AA

While historically threatening to human life and property, river floodsplay an essential role in building and sustaining healthy wetlands.

1. Floodwater carries nutrients and sediment. 2. Sediment settles. 3. Plants take root.4. Plants trap more sediment. 5. Biomass increases. 6. Wetlands emerge.

River Water Builds Wetlands

1 3 45 6

2

WATERMARKS August 2003 Number 23WATERMARKS August 2003 Number 23

5

Diversions: Routing Water into WetlandsON AN AVERAGE DAY, theMississippi River propels overhalf a million metric tons ofnutrients and sediment intothe Gulf of Mexico, while thewetlands just beyond its banksstarve for lack of these veryelements. To deliver the river’smarsh-building ingredientswhere needed, four major kindsof diversions penetrate thelevees and direct river waterinto the wetlands.

Crevasses, Old and SimpleThe simplest type of diversionis a crevasse, a fissure in thenatural levee where the riverspills through. The earliest

crevasses occurred at weakpoints in the embankment, butagencies managing the coastalregion today are cutting newones to assist in wetlandsrestoration. For example, theDelta-wide Crevasses Project inlower Plaquemines Parishproposes to make and maintainup to 30 breaches over 20 years’time, producing a net increasein the area and quality of freshand intermediate marsh.

Siphons’ Scale Adaptableto Location“Siphons are like huge strawsarching over the riverbank,sucking river water in at one

end and spewing it out into thewetlands at the other,” saysChuck Villarrubia, coastalscientist for the LouisianaDepartment of Natural Re-sources. “To establish suctionyou have to prime siphons, andship traffic or low river levelscan break the suction, makingthese diversions difficult tooperate.” They are relativelyinexpensive to construct,however, and numerous smallsiphons can be used up anddown the river to pinpointdelivery of fresh water.

Gated Structures ControlOutflowLarger-capacity gated struc-tures employ box-like culvertsthat tunnel through the levee,diverting water into a receivingarea or canal before it entersthe estuary. Operators can openor shut gates fitted into themouths of the culverts tocontrol the timing, volume andvelocity of the freshwater flowinto the outflow area, and toseasonally moderate the salin-ity level.

Results from the project atCaernarvon in Breton Sounddemonstrate the advantages ofa gated structure. In its 12

Courtesy of USA

CE N

ew O

rleans District

Gated structure at Caernarvon, Breton Sound

Canal ▼▼

Gated culvert

Mississippi River

Outflow Area

WATERMARKS August 2003 Number 23WATERMARKS August 2003 Number 23

6

Crevasse

years of operation, Caernarvonhas increased over seven-foldthe size of freshwater plantcommunities, reduced the areaof saltwater vegetation by over50 percent, rejuvenated fish andwildlife populations, and stabi-lized the marshes. Built withfunds from the Water ResourcesDevelopment Act, Caernarvonis a model for other gatedprojects, guiding their responseto changing weather conditions,growth cycles of shellfish,natural threats such as marsh-grass dieback, or requirementsof commercial and recreationalusers of the wetlands.

Experiments indicate thatpulsing — releasing a largequantity of water over a rela-tively short period of time —may best simulate natural

floods. According to John Day,professor of oceanography andcoastal sciences at LouisianaState University, pulsing pushes

fresh water and nutrients overa wide expanse without over-freshening the outfall area. Asdemonstrated when Caernarvonoperated for brief periods at itsfull capacity, pulsing may alsoprove useful for land-building

purposes.

SedimentDiversionsBuild LandLargerparticles ofsediment arecarried deepin the river’schannel. Toclaim themfor land-

building purposes, sedimentdiversions would make largecuts down into the river bank toallow tens of thousands of cubic

feet of sediment-laden water topass into the marsh everysecond. Slated for constructionin 2003, the first diversion ofthis kind, West Bay, is expectedto create almost 10,000 acres ofmarsh. The U.S. Army Corps ofEngineers suggests that moresuch diversions, placeddownriver from populatedareas, can effectively combatthe problem of coastal land loss.

Coastal restoration requiresa variety of techniques, includ-ing the use of diversions ofvarious scales, to achieve theage-old accomplishments ofnature. Diversions combinescience and engineering tobenefit the natural world andthe human population that sodepends on it.

Courtesy of NO

AA

Man-made crevasses direct waterborne nutrientsand sediment into specific areas of the wetlands.

Crevasses occur naturally as the river breaks through weak points inthe bank and floods the adjacent marshes.

Courtesy of NO

AA

WATER MARKS

Natural Crevasse

Man-made Crevasse

Crevasse ▼

Crevasse

WATERMARKS August 2003 Number 23WATERMARKS August 2003 Number 23

7

TO THE MODERN mindaccustomed to highway speeds,time in the Louisiana wetlandsmay appear as fixed and eternalas the unblinking eye of analligator. But the rate of changeis quickly accelerating aslevees, canals and other man-made structures contribute tothe wetlands’ rapid decline.

To counteract their detri-mental impact, advocates ofcoastal restorationstrongly urge usingdiversions to replicatenatural processes andrejuvenate the wetlands.However, when humansimpose control overnature, disputes inevita-bly erupt over how toexercise that control andwhom to hold responsiblefor the consequences.Debates over usingdiversions concentrate onfour issues: fisheries,water quality, floodingand navigation.

FisheriesHistorically, oystermen havebeen proponents of riverdiversions, citing as benefits thereversal of saltwater intrusion,the increase in areas of optimal

Diversion Critics Question Impacton Economy, Environment

salinity for oyster production,and the decrease of predatorsfound in high-salinity areas.Lately, however, oystermenhave voiced concern thatmodern large-scale diversionsdamage present-day fisheries bychanging the salinity of estua-rine waters, resulting in thedisplacement of aquatic popula-tions and the reduction of catch.“Restoring normal and healthy

salinity levels throughout anestuary is an important goal ofdiversions,” confirms AllenBolotte, district conservationistfor the Natural ResourcesConservation Service. “We’dlike to return marshes to thegraduated levels of an earlier

time, when the interface offresh water and salt was opti-mal. This would promotevegetative growth, marshdevelopment, and a greaterdiversity of plants, animals andfisheries throughout the coastalzone.”

For Bolotte, and many othersstudying the issue, a keyquestion is how to ensure thesustainability of coastal Louisi-

ana while protecting thelivelihoods of people whodepend on the wetlandstoday. “In the long run,diversions enhancehabitat and increaseproductivity,” Bolottesays, “but in the shortterm, in the life of coastalfishermen relying on adaily catch, their effectcan be costly and disrup-tive.”

Because oysters grow instationary beds, unable tomove when salinity levels

change, oystermen are espe-cially vulnerable to the effectsof diversions. Acknowledgingthat people who suffer economicdamage are justified in seekingreasonable compensation, thestate of Louisiana and otherconcerned parties have devised

Courtesy of LA D

ept. of Tourism

Oyster fisheries benefit in the long run asdiversions enhance and sustain Louisiana’scoastal ecosystem.

WATERMARKS August 2003 Number 23WATERMARKS August 2003 Number 23

8

a method for calculating lossesincurred by oyster leaseholdersthat considers the value of boththe oyster beds themselves andthe crops they support.

Water QualityBy mid-20th century, pollutionpouring into the Mississippifrom agricultural run-off,municipal sewage systems andindustrial wastes earned theriver a reputation as a dirtytoxic soup. Although the qualityof river water began to improveafter the passage of the Clean

Water Act in 1972, fears aboutcontaminants such as insecti-cides, herbicides and fertilizerspersist.

Scientific studies over thepast decade document thehealth of the river. Tests for 100toxic chemicals revealed thepresence of only five, and thesein low concentrations. Traceminerals detected in fish arewell within safe limits foredibility, and concentrations ofmodern pesticides fall belowEPA standards for drinkingwater. Throughout the water-

shed, improvements to wastetreatment facilities havedramatically reduced bacteriallevels in the river.

Overabundance of nitrogenand phosphorus could causeexcessive algal growth harmfulto the marsh ecosystem, but, asBolotte points out, “At theirpresent scale, diversions simplydo not convey enough waterinto the wetlands to make algalblooms a threat.” Wetlandshave been able not only toabsorb river-borne nutrientsbut actually to benefit from

Oyster Yields Increase After Caernarvon Diversion OpensOysters Available on the Public Grounds East of the Mississippi River

5,000

4,500

4,000

3,500

3,000

2,500

2,000

1,500

1,000

500

Barr

els

X 1

000

Year

'74 '76 '78 '80 '82 '84 '86 '88 '90 '92 '94 '96 '98 '00'75 '77 '79 '81 '83 '85 '87 '89 '91 '93 '95 '97 '99

Courtesy of LaDN

R CRD

Seed and Sack Oysters(Barrels X 1000)

Pre-diversion

Post-diversion

Freshwater diversionsbegin at Caernarvon

WATERMARKS August 2003 Number 23WATERMARKS August 2003 Number 23

9

One Percent of River Currently Flows Through Diversions

Percentagesbased onaverage flowand rounded

Capacitybased on alldiversionscurrentlyoperational

them. Furthermore, prelimi-nary research at LouisianaState University indicates thatfiltering river water throughthe marshes decreases thenutrient load carried by theMississippi, thereby reducingthe size of the hypoxic area, or“dead zone,” in the Gulf ofMexico.

FloodingA unified system of levees alongthe Mississippi River allowsmillions of people from BatonRouge to the Gulf to enjoysafety from floods. To them,purposefully breaching thelevees may appear to be folly.

The major diversions cancontrol the release of water,however, adjusting the timingand volume to local conditionsand to meet specific needs. Forinstance, increasing flow might

counter saline-borne threatssuch as brown marsh and redtide, or restraining it couldaccommodate the needs offisheries or seasonal sportsmen.Channel banks and physicalbarriers in the receiving basinsregulate outflow speed anddirection, further diminishingthe threat of flood and prevent-ing unintentional erosion.

NavigationReducing water levels in anavigation channel that cutsthrough the wetlands couldrestrict ship traffic and requiremore frequent dredging, or forcethe relocation of the channel.Presently, however, diversionsdo not draw enough water fromthe river to threaten navigation.Implementing a huge diversionsuch as the Third Delta atDonaldsonville would certainly

increase federal navigationmaintenance costs. Shippingmight also have to adapt byutilizing new channels if largediversions cause changes in thegeography of the coastal region.

Balancing Needs forSustainabilityDiversions attempt to replicatethe natural processes that buildhealthy wetlands while limitingpotential damage to the peopleand economy of coastal Louisi-ana. Inevitably there areconflicting opinions over settingpriorities and managing change.“For the benefit of the entireregion,” says Bolotte, “we needto develop consensus among thevarious concerned parties andmake wise choices that assurethe vigor and sustainability ofthe wetlands.”

6% of river’s volumecould flow through

diversions operating atfull capacity

Mississippi River

1% of river’s volume flowsthrough diversions operating

at current levels

WATER MARKS

WATERMARKS August 2003 Number 23WATERMARKS August 2003 Number 23

10

Diversions Build Hope for WetlandsThe expense of constructing andoperating diversions is a fractionof the estimated cost should the

nation fail to protect and restorethe Louisiana wetlands. Overthe next 20 years, these diver-

sion projects are expected tostabilize or create over a millionacres of wetlands.

Diversion Projects in Louisiana’s Coastal Wetlands

Diversion Project

Avoca Island Diversion & Land Building

Benney’s Bay Sediment Diversion

Caernarvon Freshwater Diversion*

Caernarvon Diversion Outfall Management

Channel Armor Gap Crevasse

Davis Pond Freshwater Diversion

Delta-Building Diversion at Myrtle Grove

Delta-Building Diversion North of Fort St. Philip

Delta-wide Crevasses

Freshwater Introduction South of Highway 82

Grand Bayou/GIWW Freshwater Diversion

Lake Boudreaux Basin Freshwater Intro &Hydrologic Mgmt

Mississippi River Water Reintroduction intoBayou Lafourche

Central and East Terrebonne Basin FreshwaterDelivery Enhancement*

Myrtle Grove Siphon

Naomi Siphon*

Naomi Outfall Management

Opportunistic Use of the Bonnet Carre Spillway

River Reintroduction into Maurepas Swamp

Small Freshwater Diversion to theNorthwestern Barataria Basin

Small Sediment Diversions

South Lake DeCade Freshwater Introduction

West Bay Sediment Diversion

West Point-a-la-Hache Siphon*

West Point-a-la-Hache Outfall Management

143

5,828

77,000

1,132

936

777,000

8,891

2,473

2,386

296

1,808

619

104,399

To bedetermined

1,119

Notmeasured

633

117

36,121**

5,134**

6,719

201

9,831

Notmeasured

1,087

Description of Project Work Acres

BenefitedProject #

TE-49

MR-13

N/A

BS-03a

MR-06

N/A

BA-33

BS-10

MR-09

ME-16

TE-10

TE-32

BA-256

TE-42

BA-24

BA-03

BA-3c

PO-26

PO-29

BA-34

MR-01b

TE-39

MR-03

BA-04

BA-4c

LeadAgency

COE

COE

COE;State ofLouisiana

NRCS

COE

COE;State ofLouisiana

COE

COE

NMFS

FWS

FWS

FWS

EPA

FWS

NMFS

State ofLouisiana/PlaqueminesParish

NRCS

COE

EPA

EPA

State ofLouisiana

NRCS

COE

State ofLouisiana

NRCS

TerrebonneBasin

Mississippi RiverDelta Basin

Breton SoundBasin

Breton SoundBasin

Mississippi RiverDelta Basin

Barataria Basin

Barataria Basin

Breton SoundBasin

Mississippi RiverDelta Basin

MermentauBasin

TerrebonneBasin

TerrebonneBasin

Barataria Basin

TerrebonneBasin

Barataria Basin

Barataria Basin

Barataria Basin

PontchartrainBasin

PontchartrainBasin

Barataria Basin

Mississippi RiverDelta Basin

TerrebonneBasin

Mississippi RiverDelta Basin

Barataria Basin

Barataria Basin

Location Project Status

Planning phase

Construction scheduledMarch 2004

Construction completed 1991

Construction completed 2002

Construction completed 1997

Construction completed 2002

Engineering and design phase

Construction scheduledMarch 2004

In construction (1st dredgingcycle completed; three moredredging cycles scheduled)

Construction scheduledspring 2004

Construction scheduledApril 2005

Construction scheduledMay 2004

Engineering and design phase

Proposed complex project

Not scheduled

Construction completed 1993

Construction completed 2002

Not scheduled

Construction scheduledJanuary 2005

Construction scheduledMay 2005

Construction completed 1993

Construction scheduledSeptember 2004

Construction scheduledSeptember 2003

Construction completed 1991

Hydrologic modeling phase

WATER MARKS

*Non-CWPPRA project**Acres of swamp

Sediment diversion

Construction of conveyance channel, sedimentretention devices, dikes, weirs; 50,000 cfs

Construction of five culverts and inflow and outflowchannels

Construction of flow-through culverts with watercontrols at eight sites, three plug closures with armor;restoration of 13,000 feet of spoil bank

Enlargement of existing crevasse to allow additionalflow and sediment deposition

Construction of four gated culverts, inflow and outflowchannels, guide levees and rock weir

Installation of five gated box culverts and a conveyancechannel; construction of a pump station

Construction of new conveyance channel with cutsallowing fresh water to divert into adjacent open waters

Construction of five new crevasses; dredging ofexisting crevasses; installation of plug in Raphael Passcrevasse to force more water through splays

Installation of water control structures; plug removal,structure modification; canal enlargement

Deepening existing channel and installation of weir toreduce saltwater intrusion and retain fresh water

Dredging and installation of sluice gates and outfallmanagement structures for fresh water introduction

Installation of receiving intake structure/siphon system;1,000 cfs

Improve distribution of fresh water from the GIWW

Installation of six siphon pipes; construction of leveedoutfall channel to facilitate distribution of fresh waterand sediments; 2,100 cfs

Installation of eight siphons

Installation of two weirs to maximize sedimentretention and nutrient uptake

Raising spillway pins to allow flow and reduce salinities

Installation of two culverts; construction of receivingpond; 1,500 cfs

Installation of siphons; gapping of spoil banks andculverts

Construction of conveyance channels

Installation of water control structures on south shoreand enlargement of canal

Construction of a conveyance channel; 20,000 to50,000 cfs

Installation of eight 27-inch tubes to siphon water

Installation of three earthen plugs and three weirs;restoration of channel banks to enhance distributionand reduce saltwater intrusion

WATERMARKS August 2003 Number 23WATERMARKS August 2003 Number 23

11

WaterMarks Interview ... continued from back cover

really a kind of toxic soup thatwill kill off our wetlands ratherthan restore them, but waterquality testing has shown thatthe river is remarkably free oftoxins.

WaterMarks: So you’re notworried about toxicity at all?

Schexnayder: Not at all. Thereal concern has been aboutexcessive nutrients, and that’snot been a problem to date.Nutrients themselves aren’ttoxic. Coastal wetlands assimi-late nutrients rapidly — in factthey respond by actually in-creasing their capacity to utilizethem. Additional nutrientseventually express themselvesfurther up the food chain asmore shrimp, more fish, morebirds and so forth. Even the so-called “toxic” blue-green algaeare an important food to manyestuarine organisms.

WaterMarks: What aboutdiversions’ effects on fisher-ies? Don’t oyster fishermenoppose diversions?

Schexnayder: The shortanswer is no. Oystermen havelong recognized that freshwater improves oyster produc-tion. If we can return to moretraditional salinity levels it’llbe a big positive for oystermen

in the long term. It’ll eliminatethe cost of improving oysterbeds higher in the estuariesand reduce the dangers frompollution. And most impor-tantly, oyster production willincrease significantly.

WaterMarks: Isn’t there a“Yeah, but …” here?

Schexmayder: The problem isthat we are talking long term.The data we have show that thefirst two years after a diversionbecomes operational can be themost disruptive. After that thebands of fresh and brackishwater expand and oysterproduction begins to increasewell beyond what it was beforethe diversion. We need a bridgefor the fishing industry that willtake us over the short-termproblems and get us to the long-term advantages. It’s criticalthat some form of reasonablecompensation for losses, in

addition to the oyster-leaserelocation program, be includedin our thinking about diver-sions.

We need to reach out andinvolve user groups likeoystermen, commercial andsport fishermen — not blamethem. They could become apowerful force in the effort tosave coastal wetlands.

WaterMarks: You emphasizethe difficulty and complexityof really addressing theproblem of coastal wetlandsloss in Louisiana. Howhopeful are you about thefuture?

Schexnayder: I’m concernedthat coastal wetlands loss willalways be a Louisiana problem— that it won’t ever become apriority for this nation and wewon’t ever have the dollars toseriously address the issues.But I’m also very concernedthat if coastal wetlands lossdoes become a national priority,it will be because Louisiana hassuffered a catastrophe — onecosting significant loss of lifeand billions of dollars indamage. My hope is that wehave the foresight as a nationto act now rather than react toa disaster later.

Every link in the food chaindepends on nutrientsin the ecosystem.

Courtesy of LA D

ept. of Tourism

WATER MARKS

First Class MailPostage and Fees Paid

U.S. Army Corps of EngineersNew Orleans District

Permit No. 80

DEPARTMENT OF THE ARMYNEW ORLEANS DISTRICT, CORPS OF ENGINEERSP.O. BOX 60267NEW ORLEANS, LOUISIANA 70160-0267

OFFICIAL BUSINESS

continued on page 11 …

Schexnayder: We tend to talkabout diversions as if they wereall the same. But diversionsrange from small siphons movingwater at 250 cubic feet per secondto proposed structures with thecapacity of 200,000 cfs. So it’s notso much a case of limitations as amatter of matching the rightdiversion to the project. In somecases, a series of small siphonsmight be a better fit than onelarge structure.

WaterMarks: I’ve heard youuse the term reintroductionsinstead of diversions. Why?

Schexnayder: Diversions imply

WaterMarks: Many plannersargue that diversions are theonly option available to saveLouisiana’s coastal wetlands.Are diversions really theanswer?

Schexnayder: While we wouldall like to find a silver bullet,there just isn’t one out there.And as powerful as they are,diversions are only one tool inthe toolbox. Protecting what’sleft of Louisiana’s coastal wet-lands is going to require mul-tiple, complex and expensivesolutions.

WaterMarks: So diversionshave their limitations.

that we’re changing a naturalprocess, taking something awayfrom the river. The facts are justthe opposite. Breaching a leveerestores a natural process offlooding that has always beenpart of the river. We’re re-introducing water to wetlands ina way that replicates whathappened before the leveesystem was built.

WaterMarks: But isn’t theriver is full of chemicals andfertilizers that will damagethe wetlands?

Schexnayder: Some peopleworry that the Mississippi is

The WATERMARKS Interview

Mark SchexnayderMark Schexnayder serves as a regional coastal advisor forfisheries in the Louisiana Sea Grant College program andthe Louisiana State University Agricultural Center. He hasalso worked as director of the Marine Biological Lab onGrand Terre and as manager of the state crustaceanprogram. He is shown in the photograph with hisdaughter Ava Eugenie, fishing in New Orleans City Park.

WATERMARKSWATERMARKSLouisiana Coastal Wetlands Planning, Protection and Restoration NewsLouisiana Coastal Wetlands Planning, Protection and Restoration News August 2003 Number 23August 2003 Number 23