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Characterization Report
Louisiana State Reservoir Priority and Development Program
Basin Characterization Report for the Mississippi River Delta Basin
The Louisiana Department of Transportation and Development (DOTD) is responsible for reviewing and prioritizing proposed reservoir projects for which State of Louisiana (State) funding is being sought, and then recommending projects to the State Legislature. To support reservoir project review, prioritization, and recommendation efforts, DOTD has prepared characterization reports of water resources conditions in each of the nine principal surface water Report Topics Page basins in the State. These characterization reports provide an overview of water uses, Basin Overview...... 2 needs, and concerns, and can be used by applicants for State funding, and by State Land Use and Legal Entities...... 4 agencies as they evaluate the applications. The basin characterization reports also Physiographic and Climatic contain extensive references that interested parties can use to find more information Information...... 5 from Federal, State, and local agencies or other sources. The reports represent a Water Use...... 6 “snapshot” of conditions in early 2009 (or when the references cited in the reports Surface Water...... 9 were published). Groundwater...... 13 Flooding...... 16 Based on available data, this basin characterization report provides an overview of the Environmental and Cultural Issues...... 16 water uses, needs, and key water resources concerns for the Mississippi River Delta Recreation, Navigation, and Basin (MDB) (Map 1). Additional technical information on important issues may be Hydropower...... 19 provided in separate technical reports. Interbasin and Interstate Issues...... 20 Summary of Water Resources Needs...... 20 Abbreviations and References...... 22
Red Bayou River ARKANSAS Macon Ouachita River Legend *# Major Cities
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o Major Streams
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t ATCHAFALAYA- TECHE-VERMILION Shreveport *# ¨¦§20 CALCASIEU-MERMENTAU Lake r LAKE PONTCHARTRAIN- LAKE MAUREPAS Bistineau ve Ri f n eu o S o c MISSISSIPPI RIVER DELTA a Wallace B a bi n Lake M R e iv O e u u OUACHITA RIVER r a o y c r R h a e i e d ta B v i PEARL RIVER R R R i i v v s e e r r a s Saline n RED RIVER D e Lake ug T Clear de SABINE RIVER R mo Lake iv n r e a e r v i R TENSAS RIVER
i p p i s s i s s i Toledo ¨¦§49 M 010 20 40 60 80 Bend Reservoir Miles Catahoula Lake MISSISSIPPI Red River
TEXAS Cocodrie Lake Tangipahoa
C B o a Whiskey River c y Chitto o ou d r Creek i r e e v i R
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White Lake Lake Salvador Mississippi Gulf of Mexico River Delta
Map 1. Major Surface Water Basins of Louisiana1
1 Basin Overview The MDB is located in southeastern Atchafalaya-Teche-Vermilion Basin levees along the Mississippi River and Louisiana and has an area of 8,365 to the west, and the Gulf of Mexico its distributaries. The southern MDB is square miles (Map 2).2 The MDB is to the south and east. The MDB is in the Coastal Zone, as delineated by bounded by the Lake Pontchartrain- characterized by low-lying land, with the the Louisiana Department of Natural Lake Maurepas Basin to the north, the only elevation relief provided by natural Resources (LDNR). ± Ascension Iberville 0 20 40 St. John New Orleans the Metropolitan Area Scale in Miles B St. a Assumption y Baptist o James Luling u St. Orleans L afou Charles r B ch ay St. Martin e A o l u Thibodaux Raceland le D m es Morgan an Lake B d Salvador City ay s ou Bayou B M la Cane iss St. Mary ck Lafourche is Gul sip f Int G pi racoas Jefferson ra R Wat tal Houma n iv erway d Ba er B y a ou y o Terrebonne u L a f o u Plaquemines r c h e
Legend Scenic Rivers Main Waterways Lakes, Reservoirs, Canals and Other Water Features Cities Coastal Zone Boundary Mississippi River Delta Basin Parishes Map 2. Parishes, Main Waterways, and City Boundaries3
2 Thirteen parishes are either completely 550,000 or partly encompassed by the MDB (Map 2). The southern part of the New 500,000 Orleans metropolitan area, Houma, and several smaller cities are within the 450,000 MDB. Estimated total population in the 400,000 MDB in 2005 was 523,583. Table 1 shows the 2005 population distribution 350,000 Total Basin PopulationBasin Total in the MDB by parish. Figure 1 shows PopulationBasin Total historical population in the basin. 300,000 1960 1970 1980 1990 2000 2010 Population in the MDB increased Year significantly in the 1960s and 1970s, but has generally remained constant since Figure 1. Historical MDB Population about 1980. Future population growth within the basin would increase the demand for high quality potable water sources. Principal economic activities in the MDB are related to oil and gas exploration and processing, but also include food processing and fertilizer manufacturing.5 Oil and gas production, petrochemical manufacturing, shipbuilding, tourism, and the arts and entertainment industries are growing in the region.6
Table 1. MDB Population by Parish in 20054 Parish Population Ascension* 11,493 Assumption 22,859 Iberville* 535 Jefferson* 175,530 Lafourche 91,433 Orleans* 41,063 Plaquemines* 22,907 St. Charles* 23,450 St. James* 8,745 St. John the Baptist* 3,655 St. Martin* 1,615 St. Mary* 14,069 Terrebonne 106,230 TOTAL 523,583
*Parish is located in more than one basin; population estimated for the area within the MDB. MDB=Mississippi River Delta Basin
3 8 Land Use and Legal Entities Map 3 shows 2003 land uses in TThe MDB contains a small amount of either to surface water or groundwater. the MDB. The principal land use is land considered Prime Farmland by the Existing oil and gas infrastructure and wetlands, with some agricultural land Federal Natural Resources Conservation mineral rights holdings may present along Bayou Lafourche. Economic Service (NRCS).9 The NRCS must potential impediments to development modeling for 2020 indicates that be contacted regarding proposed of surface water resources. Table 2 forested land uses may decrease irreversible conversion of any Prime lists legal entities in the MDB that may between 10 to 20 percent in the eastern Farmland for reservoir construction affect or be affected by water resource MDB, with less reduction in the western and water storage. Many oil and gas development. MDB. Simultaneously, urban land uses fields are present throughout the basin may increase by 25 to 50 percent in the (Map 3). Oil and gas drilling can require eastern MDB, with smaller increases in large amounts of water for extraction, the western MDB.7 which then needs to be disposed,
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Legend ! Oil/Gas Fields Developed, Low Intensity Forest Land Use Developed, Medium Intensity Natural Vegetation Open Water Developed, High Intensity Pasture or Crops Developed, Open Space Barren Wetlands Map 3. MDB Land Uses in 20038
4 Table 2. MDB Water Resources Legal Entities Legal Entity Responsibilities Regional Planning Commission for Jefferson, Orleans, Plaquemines, St. Bernard, Planning and development in southeast Louisiana and St. Tammany Parishes South Central Planning and Development Commission Planning and development in south central Louisiana
MDB=Mississippi River Delta Basin
Physiographic and Climatic Information Map 4 shows general basin topography. is characterized by flat lands with is 2 feet below mean sea level. The The MDB is dominated by the Alluvial interconnecting streams that allow highest point is 44 feet above mean sea Plains physiographic region, which flow between some river basins. level, on the northern basin boundary. The lowest elevation within the MDB
Basin High [_ ± 0 20 40
Scale in Miles
[_ Basin Low
Legend Elevation Relative to Mean Sea Level (Feet) Basin High : 44
Basin Low : -7 [ Highest/Lowest Elevation Locations Map 4. MDB Topography10
5 Soils in the MDB vary from north Average annual rainfall throughout the increases from west to east from 68 to south. In the north, soils are MDB varies geographically from 60 to to 70 degrees Fahrenheit (°F).12 The characterized by loamy and clayey low 65 inches per year, increasing from east average high temperature at Houma terraces and floodplains, with sandy to west.12 Figure 2 shows historical during the warmest months, July and loamy alluvial natural levees and annual precipitation at Houma, which and August, is 91°F; the average low low terraces. In the central MDB, soils tends to vary between about 40 and temperature during the coldest month, comprise brackish organic and mineral 105 inches per year, with a historical January, is 43°F.13 deltaic deposits. The southernmost average of about 63 inches per year. coastal area of the MDB has saline Average annual temperature generally organic and mineral deltaic deposits.11
120 Annual Total 100 Historical Average
80
60
40
Precipitation (inches) Precipitation 20
0
Figure 2. Historical Annual Precipitation at Houma12
Water Use Water use in the MDB is summarized in 2005, power generation used the most Plaquemines Parish Water Works – Table 3 by sector, water type, surface surface water, totaling over 515 mgd, 7 mgd water body, and parish, as reported followed by public supply and industry. St. Charles Water Works District 1 – for 2005. Table 3 is based on water Industrial surface water was used in 4 mgd withdrawal data, which may be greater the MDB for producing paper and food St. Charles Water Works District 2 – than total water consumptive use. products, as well as petroleum refining. 4 mgd For example, the power generation The following municipal water suppliers Terrebonne Water Works District 1 – sector withdraws water for both steam reported surface water use exceeding 2 9 mgd 14 generation and cooling, uses which do mgd. Thibodaux Water System – 3 mgd not entirely consume the withdrawn Assumption Water Works District West Jefferson Water Works – water and allow a large percentage of 1 – 3 mgd 24 mgd the water to be returned to a waterway. Gretna Water Works – 3 mgd Westwego Water System – 3 mgd In 2005, water use totaled over 600 Lafourche Parish Water Works District million gallons per day (mgd), over 560 1 – 10 mgd mgd of which were surface water. In
6 Only about 10 percent of the total multiplying total parish groundwater this period. The largest surface water water used in the MDB in 2005 was use by the percentage of total parish uses fluctuated without any apparent groundwater. Industry and aquaculture population within the MDB (Table 3); increasing or decreasing trend, including dominated MDB 2005 groundwater actual groundwater use by parish may power generation, municipal supply, withdrawals. The largest industrial differ from this estimation. and industry. Aquaculture use appears use of groundwater in the MDB was to have shifted from surface water to Figure 3 shows trends in surface water for chemical manufacturing. Because groundwater between 2000 and 2005. and aquifer water use in the MDB at groundwater use is not reported by 5-year intervals from 1990. Both surface surface water basin, individual parish and groundwater use fluctuated during groundwater use was estimated by
Table 3. Water Use in the MDB in 200514 Sector Surface Groundwater Surface Water Use (mgd) Parish Surface Groundwater* Water (mgd) (mgd) Body Water (mgd) (mgd)
Aquaculture 0.0 22.8 Bayou Lafourche 34.2 Ascension 1.5 1.5 General irrigation 0.1 0.1 Humble Canal 2.2 Assumption 4.8 15.0 Gulf Intracoastal Industrial 13.2 20.5 4.4 Jefferson 0.0 1.1 Waterway Inner Harbor Livestock 0.2 0.1 18.6 Lafourche 29.3 13.7 Navigation Canal Power generation 515.9 0.4 Lake Verret 1.3 Orleans 515.9 0.5 Mississippi River Public Supply 31.9 0.7 499.0 Plaquemines 1.7 0.0 Gulf Outlet Rural domestic 0.0 0.8 Other (not listed) 2.5 St. Charles 2.2 2.3 TOTAL 561.3 45.4 TOTAL 562.2 St. James 0.1 9.4 St. John the Baptist 0.9 1.1 St. Mary 0.9 0.9 Terrebonne 4.9 0.0 TOTAL 562.2 45.4 * Groundwater use estimated for parishes with at leave five percent of their population within the MDB. MDB=Mississippi River Delta Basin mgd=million gallons per day
7 Recent Historical Surface Water Use
mgd=million gallons per day
Recent Historical Groundwater Use
mgd=million gallons per day
Figure 3. Trends in Water Use in MDB by Sector15
Per capita water use in 2005 (based in Orleans Parish.14 Typical per capita parishes, but mainly used in others. on reported rural domestic and public water use rates in the U.S. range from More representative per capita water supply uses, by parish and population) 100 to 300 gpcd. The large differences use estimates could likely be calculated for MDB parishes varied from 46 between parishes suggest that water based on municipal water service gallons per capita (person) per day may have been withdrawn in some provider data. (gpcd) in Terrebonne Parish to 293 gpcd
8 Surface Water streamflow. Additionally, most available The MDB contains 44.6 miles of streams Primary surface water features in the streamflow records are discontinuous, designated under Louisiana’s Natural MDB include rivers, streams, bayous, which does not allow calculation of and Scenic River System (shown in rivers, reservoirs, and canals such as typical streamflow statistics. Available Map 2), as created by the Louisiana Bayou Lafourche, Lac Des Allemands, streamflow and stage data may be Natural and Scenic River Act. These Lake Salvador, the Gulf of Mexico, obtained directly from the USGS NWIS waterways are protected by a permit 17 and Fourleague Bay (Map 5). Map 5 Web site. process and certain prohibitions against channelization, impoundment also shows the two subwatersheds, or Bayou Lafourche is one of the larger construction, and channel realignment.18 hydrologic unit codes, delineated by the streams in the MDB. The majority U.S. Geological Survey (USGS) in the of flow in Bayou Lafourche is from The limited published information about MDB. pumping out of the Mississippi River at lakes and reservoirs in the MDB is 14 5 An extensive amount of surface and Donaldsville. summarized in Table 4. groundwater data for Louisiana, Table 4. Characteristics of Major MDB Lakes including streamflows and lake levels, Name Surface Area Storage is available through the USGS National (acres) (acre-feet) Water Information System (NWIS) Web Lac Des Allemands >14,000 NA site. However, little streamflow data is Lake Salvador >44,000 NA available for the MDB. Most gages in MDB = Mississippi River Delta Basin the basin record gage height (stage), not NA=not available ± Mis 0 20 40 siss ippi Rive East Central Lac Des r Scale in Miles Allemands Lake Louisiana Coastal Lake Verret Cataouatche B ayou Lafo Lake urch Lake e Boeuf Lake Palourde West Central Salvador Louisiana Coastal
Gulf Intracoastal G ra l n Waterway d
na B B a a y e a o C a n y u u n o o o u um y ion b t L o a e a Fourleague B r H f r o iga Bay e u v T r a c
N h e Gulf of Mexico
Gulf of Mexico
Gulf of Mexico
Legend Rivers Hydrologic Unit Mississippi River Delta Basin Reservoirs, Canals and Other Water Features
Map 5. Surface Water Features16
9 Surface Water Quality water bodies, such as fish and wildlife records request process.20 Design The 303(d) list (named after Section propagation, recreation, or drinking of new reservoirs either impounding 303(d) of the Federal Clean Water Act) water supply, may be impaired. Stream impaired waters or discharging to included in Louisiana’s Integrated Water and lake sub-segments on the 2006 impaired waters would need to consider Quality Report provides an overview of 303(d) list for the MDB are shown in these water quality challenges and surface water locations where water Map 6. Additional information on any ongoing or planned water quality quality standards are not met.19 In all dischargers in Louisiana can be improvement projects. these cases, designated uses of the obtained from LDEQ through their public
LA0007439 ± LA0007374 0 20 40 LA0073521 (! Lac Des (! (! LA0004367 Scale in Miles Lake Allemands (! LA0038059 (! (! LA0038105 Verret LA0032131 B (! (! ay A ou B lle De LA0042048 Lake LA0032948 (! ayo m s L u and Palourde afou s Lake rc Salvador (! he LA0065986 (! G LA0040207 (! LA0006131 ulf In tracoas W ta LA0040274 (! B ater l a way y o (! u L LA0049492 a Fourleague f o Bay ur c h e Gulf of Mexico
Legend Major Discharge Permit Sites (! Industrial (! Wastewater 303(d) Impaired Waters Mississippi River Delta Basin Parish Boundary
Map 6. MDB Impaired Waters from 303(d) List and Major Permitted Discharge Sites21
10 Table 5 summarizes the number of plants, storm runoff, and combined Surface waters in the MDB are also stream and lake sub-segments on the sewer overflows, cause most nutrient affected by saltwater encroachment 2006 303(d) list, and identifies impaired and many low dissolved oxygen and from the Gulf of Mexico. Saltwater uses and the parameters causing fecal coliform impairments. Boat can travel up stream channels and impairment. Most of the major water discharges are also a source of bacterial hinder the functioning of municipal bodies in the MDB are impaired; the contamination in the Intracoastal intakes. Saltwater encroachment in greatest number of stream and lake Waterway and Bayou Terrebonne. the Mississippi River affects municipal sub-segments are considered impaired water supplies for Plaquemines Nonnative plants impair many of the for nutrients and low dissolved oxygen. Parish, particularly when flows in the lakes and some of the rivers in the MDB. Fish and wildlife propagation is the most Mississippi River are low.5 Lac Des Allemands, Lake Salvador, Lake frequently affected use in the MDB. Verret, and Lake Boeuf are the larger Municipal sources, including septic lakes impaired by non-native aquatic tanks, package wastewater treatment plants.
Table 5. Summary of MDB Surface Water Quality Impairments19
Impaired Use Sub-segments Parameter Causing Impairment (affected use) Sub-segments Fish and wildlife propagation 136 Nutrients (FWP) 43 Oyster propagation 13 Dissolved Oxygen (FWP) 33 Primary contact recreation 6 Nonnative Aquatic Plants (FWP) 25 Outstanding natural resource 5 Fecal Coliform (OYS and PCR) 19 FWP=fish and wildlife propagation Total Dissolved Solids (FWP) 9 MDB=Mississippi River Delta Basin ONR=outstanding natural resource Chloride (FWP) 8 OYS=oyster propagation Sulfates (FWP) 8 PCR=primary contact recreation (swimming) Turbidity (FWP and ONR) 8 Total Suspended Solids (FWP and ONR) 4 High pH (FWP) 2 Mercury (FWP) 1
11 Permitted Surface Water discharges are summarized in Table include power facilities, industrial Discharges 6 and major industrial permitted chemical facilities, and refineries; each The Louisiana Department of discharges in Table 7. Dischargers discharges between 1 and 15 mgd. Environmental Quality (LDEQ) issues that are physically located in the MDB, Discharge permit conditions are based permits for discharges of municipal but discharge to the Mississippi River, on receiving-water low-flow quantity and industrial wastewater. Permitted are not listed. The Terrebonne Parish and quality. Future water development discharges classified as “major” by Houma North facility has the largest projects that change low-flow quantity the U.S. Environmental Protection municipal discharge at 16 mgd, followed or quality at the discharge location could Agency (USEPA) (generally those with by the New Orleans West Bank facility, affect the ability of permit holders to flow greater than 1 mgd) are shown in with a permitted discharge of 10 comply with permit conditions. Map 6. Major municipal wastewater mgd. Permitted industrial dischargers
Table 6. Major Municipal Wastewater Discharge Permits in the MDB22 Discharger Permit Number Permitted Flow Receiving Water Parish (mgd) Marrero LA0042048 9.6 Jefferson Jefferson Morgan City LA0065986 4.5 Bayou Boeuf Saint Mary New Orleans West Bank LA0038105 10.0 Orleans Canal/Mississippi River Orleans Saint Charles Parish (Luling) LA0032131 2.6 George Cousin Canal St. Charles St. Charles Parish Council LA0073521 1.7 Providence Canal St. Charles Terrebonne Parish Houma North LA0040207 16.0 Louis Canal-Bayou Terrebonne Terrebonne Terrebonne Parish Pollution Control (South) LA0040274 8.0 Houma Navigation Canal Terrebonne Thibodaux, City of LA0032948 8.0 Phillips Canal/Terrebonne Lafourche Westwego, City of LA0038059 4.5 WPCA Canal Jefferson
Information presented in this table is directly from USEPA (2009a). For detailed explanation, this reference should be consulted. mgd=million gallons per day MDB=Mississippi River Delta Basin
Table 7. Major Industrial Discharge Permits in the MDB22 Discharger Permit Permitted Receiving Water Type Parish Number Flow (mgd) Industrial organic Cytec Industries LA0004367 6.8 Lake Cataouatche Jefferson chemicals Entergy Louisiana LLC - Waterford 1 and 2 Forty Arpent Canal/ LA0007439 13.1 Electric services St. Charles Generating Plant Mississippi River Arpent Canal to Killona Energy Center LA0007374 14.9 Electric services St. Charles Mississippi Crude petroleum Loop INC LA0049492 1.6 Bayou Lafourche, Moreau Lafourche pipelines Intracoastal Waterway/ Valentine Paper Incorporated LA0006131 2.4 Paper mills Lafourche Barataria
Information presented in this table is directly from USEPA (2009a). For detailed explanation, this reference should be consulted. LLC=limited liability company mgd=million gallons per day MDB=Mississippi River Delta Basin
12 Groundwater The State has registered about 500 Aquifer. Each of these major aquifers Table 8. Figure 4 shows groundwater water wells in the MDB,17 most of which underlies a small area in the northern levels in the aquifer units of the Chicot are completed in the Mississippi River MDB (Map 7). Characteristics of the Equivalent Aquifer present in the MDB. Alluvial Aquifer and Chicot Equivalent major MDB aquifers are summarized in
Map 7. Spatial Extents of Major MDB Aquifers23
13 Table 8. Overview of MDB Major Aquifer Characteristics2 Aquifer Range of Thickness Typical Well Yields Hydraulic Specific Capacity Depth to of Freshwater (gpm) Conductivity (gal/min/ft of Groundwater in 2005 Interval (feet/day) drawdown) (feet)17 (feet) 500 – 4,000 Mississippi River Alluvial 50 – 500 10 – 530 5 – 90 0 – 15 7,000 (large capacity) 500 – 1,000 Chicot Equivalent 50 – 1,100 10 – 200 10 – 200 5 – 60 3,500 (large capacity) gpm=gallons per minute gal/min/ft=gallons per minute per foot of drawdown MDB=Mississippi River Delta Basin
0 surface water instead of groundwater, and areas of the aquifer have recharged
20 in Orleans Parish (Well Or-42 in Figure 4). 40 The Mississippi River Alluvial Aquifer is primarily used for irrigation and 60 aquaculture in the MDB.26 This aquifer
80 is hydraulically connected to the Or-42 (Gonzales-New Orleans) Mississippi River and its major streams. 100 ScSc-82-82 (Norco) This aquifer is recharged by direct Sj-203 (Norco) infiltration of rainfall, lateral and upward Sj-86 (Gramercy) Water SurfaceWater (feet below ground surface) Water SurfaceWater (feet below ground surface) 120 movement of water from adjacent 1980 1983 1986 1989 1992 1995 1998 2001 2004 2007 and underlying aquifers, and overbank Year stream flooding. Like the Chicot Figure 4. Historical Trends in Groundwater Levels in Representative Wells in Units of the Chicot Equivalent Aquifer17 Equivalent Aquifer, groundwater levels in the Mississippi River Alluvial Aquifer fluctuate seasonally in response to The Chicot Equivalent Aquifer is part Equivalent Aquifer units exhibit distinct precipitation and river stage. Because of the Southern Hills Aquifer System, fluctuations due to seasonal rainfall of rapid recharge from surface water, and aquifer units in this system are variation, which is characteristic of groundwater levels in the Mississippi given local names based on location surficial aquifers. River Alluvial Aquifer have not shown and depth.24 In the MDB, the Chicot The Gonzales-New Orleans aquifer long-term change. Equivalent Aquifer includes the unit of the Chicot Equivalent Aquifer Gramercy, Norco, and Gonzales-New is the primary source of freshwater in Orleans aquifers, and the 1,200-foot the area surrounding New Orleans. In sand of the New Orleans aquifers 1990, a total of 33 mgd was withdrawn although the last is not heavily used from the Gonzales-New Orleans aquifer in the MDB. As shown in Figure unit. During that time, a large amount 4, groundwater levels in the Chicot of groundwater drawdown occurred, Equivalent Aquifer units have generally centered northeast of downtown New remained constant or have increased Orleans (north of the MDB).25 However, since 1980. Within these overall municipalities now rely more heavily on trends, groundwater levels in the Chicot
14 Groundwater Quality Table 9. Summary of Secondary Drinking Water Standards Exceedences in Major Groundwater quality issues in the MDB Aquifers major MDB aquifers reported in Aquifer pH TDS Color Chloride Iron Mississippi River the 2005 and 2006 LDEQ Baseline n n n n Alluvial Monitoring Program (BMP) reports are Chicot Equivalent n n n n n summarized in Table 9.27 Water in five n – One or more wells exceeded the secondary standard wells in the Mississippi River Alluvial MDB=Mississippi River Delta Basin Aquifer exceeded the Federal primary TDS=total dissolved solids drinking water standard for arsenic in 2006; however, none of these wells are located in the MDB. No water in any of the wells tested as part of the Chicot Equivalent Aquifer BMP exceeded Federal primary drinking water standards. Water in some wells in both aquifers exceeded secondary drinking water standards for pH, chloride, total dissolved solids (TDS), color, and iron (Table 9). Although no Federal or State standard has been established for chloroform, a volatile organic compound, it was detected in very low levels in one Chicot Equivalent Aquifer well; however, this well is not located in the MDB. Additionally, saltwater encroachment is a concern for aquifers in the New Orleans area in the northern MDB.5
15 Flooding Low-lying areas of the MDB are subject St. John the Baptist, St. Charles, and information system layers; detailed to periodic flooding due to intense Terrebonne) have become participants maps and reports can be obtained from rainfall, abnormally high tides in the Gulf in the National Flood Insurance Program FEMA. of Mexico, hurricanes or lesser tropical (NFIP), offered through the Federal USGS has estimated flood flow disturbances, and combinations of these Emergency Management Agency magnitudes for different return periods events. Historic flood damage has been (FEMA). As part of the NFIP, FEMA at streamflow gages throughout the substantial in the MDB, particularly in prepares Flood Insurance Studies (FIS) State. The USGS analysis is only valid Jefferson Parish. At elevations below and Flood Insurance Rate Maps (FIRM) for rural, unaltered waterways and, sea level, pumping is the only effective for rivers and bayous prone to damaging therefore, the analysis is generally method for dewatering the land surface floods in a parish; member communities not valid for gaged waterways in the after flooding.5 regulate development in floodplains. MDB, which are controlled by levees, These studies and maps document Ten of the parishes wholly or partially dikes, and other hydraulic structures. flooding problems within parishes and located in the MDB (Ascension, Table 10 lists peak discharges for delineate 100-year flood zones along Assumption, Iberville, Jefferson, major waterways, as reported in the major waterways. Some 100-year flood Lafourche, Plaquemines, St. James, FISs reviewed as part of this basin zones are available as digital geographic characterization. Table 10. Estimated Peak Flow Discharges in the MDB29
Flood Magnitude (cfs) Location 2-year 10-year 100-year 500-year
Bayou Pierre Part at mouth NA 600 1,100 1,300
Mississippi River at river mile 10-82 NA 1,250,000 1,250,000 NA
Mississippi River at St. Charles Parish boundary NA 1,375,000 1,500,000 NA cfs=cubic feet per second MDB=Mississippi River Delta Basin NA=not available
Environmental and Cultural Issues Environmental and cultural resources Habitat and Wildlife black bear, red-cockaded woodpecker, 32 are important elements of the quality The MDB includes parts of the brown pelican, and piping plover. of life in Louisiana and can affect Mississippi Alluvial Plain and the South The Federal Endangered Species Act siting and operation of water resource Eastern Plains ecoregions.31 Each gives the U.S. Fish and Wildlife Service facilities, as regulated by Federal and ecoregion contains a range of habitats, (USFWS) the authority to protect listed State permitting requirements. As some of which are associated with species and their habitat. USFWS has shown in Map 2, the southern MDB species of conservation concern. The mapped critical habitat areas for the 33 is designated by LDNR as being in the Louisiana Wildlife Action Plan prioritizes piping plover in the MDB. Coastal Zone. Existing environmental particular terrestrial habitat types within Aquatic habitats in the MDB support issues in the Coastal Zone, such as loss 18 each ecoregion for conservation. about 57 species of freshwater fishes, of wetlands and land subsidence, can 12 species of mussels, and 10 species affect water resources facilities, such as Terrestrial species Federally listed as of crawfish.18 Species of state concern reservoirs.30 threatened or endangered that may reside in the MDB are the Louisiana in the MDB include two freshwater fish
16 species and two reptile species. The Wetlands are an important of the cover, and the soil is periodically State regulates aquatic habitat through environmental resource throughout saturated or inundated) and about surface water quality standards in water the United States, and especially in 39 percent, or 1,725 square miles, is bodies designated for fish and wildlife Louisiana. Alteration of these areas emergent herbaceous wetlands (i.e., propagation.34 The Louisiana Wildlife often requires a Federal Section 404 areas where perennial herbaceous Action Plan does not prioritize aquatic permit through the U.S. Army Corps vegetation accounts for most of the habitats for conservation. USFWS has of Engineers (USACE). Map 8 shows cover, and the soil is periodically identified several subwatersheds within areas of wetlands in the MDB. About saturated or inundated).36 Wetland the MDB containing surface waters 22 percent of the MDB’s surface area, area in the MDB has been reduced by important for conservation of the fat or 982 square miles, is woody wetlands several factors, such as drainage for pocketbook mussel, Gulf sturgeon, and (i.e., areas where forest or shrubland development, enclosure within levees, pallid sturgeon, which are Federally vegetation accounts for a large portion and dredging for oil and gas canals.5 listed as threatened or endangered species.35
Map 8. Wetlands in the MDB22
17 Cultural Resources schools. There are 62 historic points The only Federally recognized Native Information on cultural issues and in the MDB, as shown in Map 9. No American tribe in the MDB is the resources is provided by parish-level archaeological sites are listed on the Chitimacha Tribe. State-recognized 37 organizations. Prehistoric (before NRHP for the MDB. Generalized tribes in the MDB are the United European colonization) and historic locations of known cultural resources Houma Nation, the Biloxi-Chitimachi sites are registered with the Louisiana that could affect reservoir siting or Confederation/Bayou Lafourche Band, Department of Culture, Recreation, operations are available from the NRHP. the Point-Au-Chien Tribe, the Isle de and Tourism (LCRT) and the National Additional information is available Jean Charles Band, and the Grand 38 Register of Historic Places (NRHP). from the LCRT, Office of Cultural Caillou/Dulac Band. Potentially Featured historic sites in the basin Development, Division of Historic affected tribes must be notified of any include churches, banks, houses, and Preservation. proposed reservoir plans.
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Wisner WMA (!0 Legend Port (!0 Ports Fourchon j[ State Parks Isles Dernieres Barrier Islands Refuge " Historic Places Landmarks Major Navigable Waterways Refuge Wildlife Managment Areas Map 9. Cultural and Recreational Resources and Navigable Waterways in the MDB3
18 Recreation, Navigation, and Hydropower The MDB is used extensively for water- Bayou Petit Caillou is a 5-foot-deep The Houma Navigation Canal is 15 oriented recreation. Fishing, canoeing, channel from Robinson Canal to the feet deep, and was completed in and boating are popular recreational Head of Bayou Little, completed in 1929. 1962. The channel allows navigation activities in the area.5 Several Wildlife Average annual traffic in the bayou from from the GIWW near the west side of Management Areas in the MDB serve 1986 through 1995 was 880,000 tons, Houma to the Gulf of Mexico. Annual as hunting and camping grounds for the consisting mostly of crude petroleum.39 traffic on the Houma Navigation Canal general public. Specific recreational between 1986 and 1995 averaged over The Adams Bay – Grand Bayou resources of regional value are shown 1 million tons. The oil industry is the Waterway, from Doullut Canal, near in Map 9. predominate user of the waterway.39 Empire, to the Gulf of Mexico, serves the The 10 major navigable waterways area’s large fishing fleet and offshore oil The GIWW is a 1,300-mile-long, within the MDB are listed in Table operations. The area of the Waterway man-made canal that runs along the 11. The Barataria Bay Waterway and from Empire to the Gulf of Mexico is Gulf of Mexico coastline, from Texas’s adjacent waters below Lafitte are used also heavily used throughout the year southernmost tip at Brownville to St. extensively by commercial fishermen for fishing and hunting. Average annual Marks, Florida. Primarily used for and oystermen, and are also sites of traffic from 1986 through 1995 was over shipping, the GIWW links all Gulf Coast special water-based recreation events.39 1 million tons.39 ports, and provides access from these ports to the national inland waterway Bayou Terrebonne is a 6-foot-deep Navigation in Bayou Lafourche extends system. In Louisiana, the GIWW channel that originates at the Gulf for over 100 miles north from the Gulf stretches 306 miles along the Louisiana Intracoastal Waterway (GIWW) near of Mexico. Average annual traffic on coastline from the Pearl River to the Houma, Louisiana. Crude petroleum Bayou Lafourche from 1986 through Sabine River, and is maintained at a is the major cargo on this waterway, 1995 was almost 2 million tons.39 depth of 12 feet. In 2006, a total of which also serves as an access route for The Bayou Segnette Waterway runs approximately 84 million tons of cargo fishing and hunting in the coastal region. from Westwego to the GIWW. The was transported through the GIWW The average annual traffic from 1986 waterway provides larger modern in Louisiana.42 The GIWW Alternate through 1995 was 230,000 tons.39 fishing and shrimping boats with a Route (Morgan City/Port Allen) extends shorter, more direct route to packing and from the GIWW at Morgan City to the canning industries on Bayou Segnette.39
Table 11. Summary of Navigable Waterways in MDB River Outflow Navigable Depth Navigable Length (feet)40 (miles) Adams Bay - Grand Bayou Waterway from Empire to Gulf of Mexico 12 11 Gulf of Mexico Algiers Canal GIWW 12 10 Barataria Bay Waterway Gulf of Mexico 12 36 Bayou Lafourche Gulf of Mexico 12 107 Bayou Petit Caillou Gulf of Mexico 5 28 Bayou Segnette Waterway GIWW 9 14 Bayou Terrebonne Gulf of Mexico 7 38 GIWW NA – traverses MDB 12 96 GIWW Alternate Route – Morgan City/Port Allen GIWW 12 25 Houma Navigation Canal Gulf of Mexico 15 55
GIWW=Gulf Intracoastal Waterway MDB=Mississippi River Delta Basin NA=not applicable
19 Mississippi River via the Atchafalaya Interbasin and Interstate Issues and Old rivers. It provides a shortcut There are no interstate compacts regional, interstate concerns. Coastal from the Gulf of Mexico to the upper MS Delta Basin affecting water resources in the MDB, issues are concerns in the MDB as well Mississippi River, shortening the route although the problems of reservoir as in other basins and states along the by 172 miles and easing port congestion x Mississippi River Delta drawdown and saltwater intrusion in Gulf of Mexico.30 at New Orleans. Average annual traffic the Southern Hills Aquifer System are from 1986 through 1995 was over 10 million tons.39 The Algiers Canal is a 12-foot deep channel from the Mississippi River to the GIWW. The canal was designed as an alternate route for the GIWW to help alleviate traffic south of the Harvey Lock area. A lock is located on the canal at the outlet to the Mississippi River.39 Two ports are located within the MDB: the Port of Terrebonne and Port Fourchon. The Port of Terrebonne is located on the Houma Navigation Canal. Tenants of the Port of Terrebonne are marine fabricators as well as oil and gas service companies needing maritime 43 facilities. Port Fourchon is the Summary of Water Resources Needs southernmost port in Louisiana. It is the intermodal support base for over half To identify and prioritize statewide to allow interbasin comparison of the domestic oil and gas activity in the water resources issues, a needs needs. To maintain objectivity in the Gulf of Mexico, the Louisiana Offshore assessment of each of the nine major evaluation process, evaluation criteria Oil Port (LOOP), substantial commercial surface water basins within Louisiana were developed based on factors that fishing interests, and significant was performed. Because the needs could be evaluated as quantitatively recreational activities. Pipe, drilling assessment provides the foundation for as possible across all basins. High, fluids, energy exploration and production developing reservoir priority evaluation medium, and low levels of current need equipment, and energy services are criteria, it focuses on needs that can be were defined based on differences in among the most common cargoes addressed by surface water reservoirs. these factors between basins. Future handled, along with personnel. Over 30 At the same time, the integrated needs in each basin were assessed million tons of cargo were handled at nature of water resources management by determining whether each current Port Fourchon in 2006.44 requires evaluating issues that could need was increasing, constant, or not necessarily be solved, but could be decreasing. The evaluation criteria are No hydropower projects exist in the affected, by a reservoir. described in detail in the main body of MDB, and there is limited opportunity the Statewide Perspective on Water for hydropower development in the Based on the existing compiled Management Report, to which this basin basin.45 information, eight categories of State characterization is an appendix. water resources needs that could be addressed or affected by construction of The assessed needs in the MDB are surface water reservoirs were identified summarized below. Details of the 7 and evaluated. Evaluation criteria assessed needs for all nine major were developed for each category Louisiana surface water basins, as well
20 as a comparison of statewide needs by Navigation was evaluated as a high- reaches of surface water are designated issue, are presented in the Statewide level need with increasing importance as having impaired water quality. Perspective on Water Management in the future. Two major ports and over Although most of these impairments are Report. 400 miles of navigable waterways, related to aquatic habitat, some affect including the GIWW, are present in the usability of water for other purposes. Assessed needs in the MDB are shown MDB, accommodating 30 million tons Furthermore, many water resources of in Table 12, and are discussed below in of commercial traffic annually. Funds the MDB are heavily used for industrial general order of need, from high-level have been requested for multiple future purposes or are situated near industrial needs (colored red in Table 12) to low- dredging projects, and Congressional activities, which can pose a risk of level needs (colored green in Table 12). authorization is pending for an $887 environmental contamination. Due to existence of widespread surface million hurricane-protection lock and Little groundwater is used in the MDB, water quality impairments and heavy floodgate to protect the GIWW from and groundwater supply was evaluated industrial activity along waterways in storm surges. as a low-level need. However, saltwater the Delta, surface water quality was Environmental protection was ranked intrusion affects groundwater quality evaluated as a high-level need. A as a medium-level need. Several on the northern basin margin near New majority of the major surface waters in environmental issues have been Orleans, and groundwater quality was the MDB are considered impaired by identified that threaten protection evaluated as a medium-level need. LDEQ. Common impairments include of existing water resources and/ nutrients, dissolved oxygen, and Recreation was ranked as a medium- or constrain future development of nonnative plants. Urban sources such level need. The MDB has the third- additional water supplies. These as sanitary sewer overflows, storm highest population of any basin in include the presence of widespread runoff, package wastewater treatment the State, suggesting high demand wetland and naturally vegetated areas plants, as well as heavy industrial for recreational facilities. The MDB covering over 60 percent of the basin; activity, are major causes of impairment. has many lakes and access to the areas considered Prime Farmland; 45 Mississippi River and its tributaries, Flood control was ranked as a high-level miles of State-designated Natural which likely meet the existing and future need. Widespread areas of potential and Scenic Rivers; and three aquatic need. flooding are present in the MDB, and several terrestrial threatened threatening a population of over half a and endangered species. Extensive million people. Comprehensive flood control projects have been conducted Table 12. Assessed Water Resources Needs in the MDB or are in the planning stages, but the risk of flood damage to highly populated Category Current Future areas is substantial, as demonstrated by Surface Water Supply medium h recent hurricanes. Significant ongoing Surface Water Quality medium h Groundwater Supply low – subsidence, combined with potential Groundwater Quality medium – sea-level rise, threatens the viability of Flood Control high h future flood control projects as well. Environmental Protection and Enhancement medium h Recreation medium – Navigation high h
MDB=Mississippi River Delta Basin Red = high-level need; Yellow=medium-level need; Green=low-level need h = increasing importance – = same importance i = decreasing importance
21 Abbreviations °F degrees Fahrenheit BMP Baseline Monitoring Program cfs cubic feet per second DOTD Louisiana Department of Transportation and Development FEMA Federal Emergency Management Agency FIRM Flood Insurance Rate Map FIS Flood Insurance Study GIWW Gulf Intracoastal Waterway gpcd gallons per capital per day LDEQ Louisiana Department of Environmental Quality LDNR Louisiana Department of Natural Resources LOOP Louisiana Offshore Oil Plant MDB Mississippi River Delta Basin mgd million gallons per day NFIP National Flood Insurance Program NRCS Natural Resources Conservation Service NRHP National Register of Historic Places NWIS National Water Information System State State of Louisiana TDS total dissolved solids USACE U.S. Army Corps of Engineers USEPA U.S. Environmental Protection Agency USFWS U.S. Fish and Wildlife Service USGS U.S. Geological Survey
22 References 1 U.S. Geological Survey (USGS). 1999. 1:2,000,000-scale Hydrologic Units of the United States. Available at
23 27 LDEQ. 2006b. Chicot Equivalent Aquifer Summary, Baseline Monitoring Program, FY 2006, Appendix 12 of the Triennial Summary Report and LDEQ 2006. Mississippi River Alluvial Aquifer Summary, Baseline Monitoring Program, FY 2005, Appendix 8 of the Triennial Summary Report. Baseline Monitoring Program reports available at
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