FINAL
Total Maximum Daily Load (TMDL)
For
Organic Enrichment & Dissolved Oxygen
Tombigbee River (Aliceville Reservoir) AL/03160106-0402-102
Pickens County, Alabama
Prepared by:
US EPA Region 4
61 Forsyth Street SW
Atlanta, Georgia 30303
October 2008
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Tombigbee River (Aliceville Reservoir) FINAL - Organic Enrichment/Dissolved Oxygen
Table of Contents
List of Figures iv
List of Tables iv
List of Abbreviations v
1.0 Executive Summary 1
2.0 Basis for the §303(d) Listing 4
3.0 Technical Basis for TMDL Development 7
3.1 Applicable Water Quality Criterion 7
3.2 Source Assessment 7
3.2.1 Nonpoint Sources 9
3.2.2 Point Sources 10
3.3 Data Availability and Analysis 13
3.3.1 Instream Water Quality 13
3.3.2 Other Available Data 15
4.0 Model Development 16
4.1 Environmental Fluid Dynamics Code (EFDC) 16
4.2 Water Quality Analysis Simulation Program (WASP) 17
4.3 Past QUAL2E Model Applications to the Tombigbee River 17
5.0 Development of Total Maximum Daily Load 19
5.1 Numeric Targets for TMDL 19
5.2 Existing Conditions 19
5.3 Critical Conditions 20
5.4 Margin of Safety (MOS) 21
5.5 Seasonal Variation 21
Prepared by US Environmental Protection Agency, Region 4. ii
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Tombigbee River (Aliceville Reservoir) FINAL - Organic Enrichment/Dissolved Oxygen
5.6 TMDL Results 22
6.0 Conclusions 25
8.0 References 27
Prepared by US Environmental Protection Agency, Region 4.
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Tombigbee River (Aliceville Reservoir)
FINAL - Organic Enrichment/Dissolved Oxygen
List of Figures
Figure 1. Aliceville Reservoir in the Tombigbee River Basin vi
Figure 2: Land Use Classification in the Aliceville Reservoir Watershed 9
Figure 3: Major Discharges of BOD to the Tombigbee River Above Aliceville
Reservoir 12
Figure 4: Model of Aliceville Reservoir showing water quality monitoring stations.... 15
List of Tables
Table 1: OE/DO TMDLs and Reductions Necessary to Meet WQS in Aliceville
Reservoir 3
Table 2: OE/DO TMDLs and Reductions Necessary to Meet WQS in Aliceville
Reservoir 3
Table 3: Landuse Distribution for Watersheds Draining to Aliceville Reservoir 10
Table 4: Major NPDES Permitted Discharges of BOD to the Tombigbee River
Upstream of Aliceville Reservoir (HUCs 03160101 and 03160106) 11
Table 5: Existing Discharge (2003-2006) for Major NPDES Facilities to the
Tombigbee River Upstream of Aliceville Dam 13
Table 6: Water Quality Stations in Aliceville Reservoir 14
Table 7: Existing Discharge (2003-2006) for Major NPDES Facilities 20
Table 8: Estimated Nonpoint Source Loads from Stennis Dam to Bevill Dam 20
Table 9: OE/DO TMDLs and Reductions Necessary to Meet WQS in Aliceville
Reservoir 23
Table 10: OE/DO TMDLs and Reductions Necessary to Meet WQS in Aliceville
Reservoir 24
Prepared by US Environmental Protection Agency, Region 4.
IV
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Tombigbee River (Aliceville Reservoir)
FINAL - Organic Enrichment/Dissolved Oxygen
List of Abbreviations
ADEM
BOD
BOD-5
CAFO
CBOD
CBODu
CFR
CFS
DMR
DO
EPA
GIS
HUC
LA
MDEQ
MOD
MOS
MRLC
NBOD
NH3-N
NOBDu
NPDES
POTW
SOD
TMDL
TN
TP
USGS
WCS
WLA
WWTP
7Q10
Alabama Department of Environmental Management
Biochemical Oxygen Demand
5-Day Biochemical Oxygen Demand
Concentrated Animal Feeding Operation
Carbonaceous Biochemical Oxygen Demand
Ultimate Carbonaceous Biochemical Oxygen Demand
Code of Federal Regulations
Cubic Feet per Second
Discharge Monitoring Report
Dissolved Oxygen
U.S. Environmental Protection Agency
Geographic Information System
Hydrologic Unit Code
Load Allocation
Mississippi Department of Environmental Quality
Million Gallons per Day
Margin of Safety
Multi-Resolution Land Characteristic
Nitrogenous Biochemical Oxygen Demand
Ammonia Expressed as Concentration of Nitrogen
Ultimate Nitrogenous Biochemical Oxygen Demand
National Pollutant Discharge Elimination System
Publicly Owned Treatment Works
Sediment Oxygen Demand
Total Maximum Daily Load
Total Nitrogen
Total Phosphorus
United States Geological Survey
Watershed Characterization System
Waste Load Allocation
Wastewater Treatment Plant
7-day Average Low Flow with a Recurrence Interval of Once in Ten Years
Prepared by US Environmental Protection Agency, Region 4.
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Tombigbee River (Aliceville Reservoir)
FINAL - Organic Enrichment/Dissolved Oxygen
Figure 1. Aliceville Reservoir in the Tombigbee River Basin
Prepared by US Environmental Protection Agency, Region 4.
VI
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Tombigbee River (Aliceville Reservoir) FINAL - Organic Enrichment/Dissolved Oxygen
1.0 Executive Summary
This report presents the Total Maximum Daily Load (TMDL) for the Tombigbee River
from Bevill Dam to the Alabama/Mississippi state line (Aliceville Reservoir), which is
listed as impaired by organic enrichment/low dissolved oxygen on Alabama's 2008
Section 303(d) list. TMDLs are required under the Clean Water Act when
technologically based controls on permitted point sources alone are insufficient to
achieve water quality standards.
Aliceville Reservoir is an impoundment of the Tombigbee River located in Pickens
County, Alabama, near the Alabama/Mississippi state line. The reservoir is operated
primarily to support navigation on the Tennessee-Tombigbee Waterway and is
characterized by low velocities and high temperatures during summer drought periods.
The contributing upstream watershed for Aliceville Reservoir occupies an area of 5,750
square miles, most of which is within the State of Mississippi.
Aliceville Reservoir has two designated use classifications: Fish and Wildlife and
Swimming. In accordance with Alabama Department of Environmental Management
(ADEM) water quality standards, the minimum dissolved oxygen (DO) concentration in a
waterbody with these use classifications is 5 mg/L, except in extreme conditions due to
natural causes where DO levels are not permitted to drop below 4 mg/L.
Aliceville Reservoir was originally placed on Alabama's 1996 § 303(d) list as not
supporting designated uses based on water quality monitoring data collected in 1991 that
showed DO concentrations less than 5 mg/L, and occasionally less than 4 mg/L. More
recent data, collected by ADEM in 1999, 2001, 2003, 2004 and 2006 and by EPA in
2005, shows that DO values in Aliceville Reservoir continue to drop below 5 mg/L.
Analysis of available monitoring data indicates that excursions of the water quality
criterion for DO in Aliceville Reservoir are associated with conditions of low flow and
high water temperatures. Under these conditions, the ability of water to hold dissolved
oxygen is reduced, the rate of reaeration of the water is slowed, and the effects of
oxygen-consuming wastes on the DO balance in the water column are enhanced.
Three models were coupled and used to predict the reductions required to meet water
quality standards. These modeling tools include: 1) an application of the watershed
model, BASINS PLOAD; 2) an application of the hydrodynamic, three-dimensional
model, Environmental Fluid Dynamics Code (EFDC); and 3) an application of the Water
Quality Analysis Program (WASP) 7.2 eutrophication model. These models were
calibrated to observed data in the reservoir.
In order to achieve the applicable water quality standards, the TMDL estimated by these
models requires a reduction of 30 percent from the total existing loads of CBODu, Total
Phosphorus (TP), and Total Nitrogen (TN) that enter Aliceville Reservoir. Although
Aliceville Reservoir is not specifically identified as impaired for nutrients on Alabama's
§ 303(d) list, reductions to TP and TN are necessary to meet a minimum DO
concentration of 5 mg/L. Based upon information currently available, the reductions and
1
Prepared by US Environmental Protection Agency, Region 4
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Tombigbee River (Aliceville Reservoir) FINAL - Organic Enrichment/Dissolved Oxygen
associated allocations for TP and TN are not expected to cause or contribute to
excursions of water quality standards to any downstream waterbodies. The sources of
CBODu, TN, and TP originate in both Alabama and Mississippi. The TMDL is
composed of three categories of allocations: 1) a wasteload allocation for the point
sources in Alabama; 2) a load allocation for the nonpoint sources in Alabama; and 3) an
aggregate allowable pollutant load, which includes both the point and nonpoint
contributions, to Mississippi sources in the Tombigbee River watershed to be allocated at
the state line. Table 1 shows the maximum daily loads that will meet and maintain water
quality standards during the critical conditions experienced each summer (June -
September). Loads for non-summer months can be higher than those in Table 1, as long
as the annual average does not exceed the allocations in Table 2.
The percent reduction required for CBODu, TN and TP represented in the tables below is
the same as the reduction prescribed in the draft TMDL EPA proposed in October 2007;
however, the calculated loads allocated in the final TMDL are greater than the calculated
loads proposed in the draft TMDL. In both the proposed and final TMDLs, loads at the
MS/AL state line are calculated using results from the same water quality model. In the
proposed draft TMDL, the loads at the MS/AL state line were based on output from one
model layer when it should have accounted for the loads from all of the layers in the three
dimensional model. This error was caught during the public comment period and the
final TMDL loads at the MS/AL state line are approximately two-thirds greater than
those reported in the proposed TMDL. The allocations in the final TMDL represent the
total assimilated loads at the MS/AL state line necessary to achieve water quality
standards.
Prepared by US Environmental Protection Agency, Region 4
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Tombigbee River (Aliceville Reservoir)
FINAL - Organic Enrichment/Dissolved Oxygen
Table 1: OE/DO TMDLs and Reductions Necessary to Meet WQS in Aliceville Reservoir
(June - September)
Pollutant
CBODu
TN
TP
ALABAMA
Coal Fire Creek
Watershed
(HUC 3160106) 1'5
LA
30% reduction
(1,200lbs/day)
30% reduction
(17 Ibs/day)
30% reduction
(4 Ibs/day)
All other watersheds
(HUC 03160101, 03160103, and
03160105) 2'5
WLA
0% reduction
(0 Ibs/day)3
0% reduction
(0 Ibs/day)3
0% reduction
(0 Ibs/day)3
LA
30% reduction
30% reduction
30% reduction
MISSISSIPPI
Aggregate allocation to
pollutants from
Mississippi at the state
border5
30% reduction
(83,956 Ibs/day)
30% reduction
(9,606 Ibs/day)
30% reduction
(1,663 Ibs/day)
TMDL4
30% reduction
(85, 156 Ibs/day)
30% reduction
(9,623 Ibs/day)
30% reduction
(1,667 Ibs/day)
The Coal Fire Creek watershed (HUC 03160106) is the only watershed in the Alabama portion of the Tombigbee River basin that
does not drain into Mississippi; therefore, loads from this watershed are not reflected in the aggregate allocation to Mississippi.
All other watersheds in Alabama (Bull Mountain Creek (03160101), Buttahatchee Creek (03160103), and Luxapallila Creek
(03160105)) drain from Alabama to Mississippi before ultimately draining back to Alabama and into Aliceville Reservoir. The only
point sources in Alabama discharge to these watersheds.
The wasteload allocation of 0 Ibs/day recognizes that there are currently no point sources in Alabama that impact dissolved oxygen
levels in Aliceville Reservoir. In order to be consistent with this wasteload allocation, any potential future discharges in Alabama can
only discharge TN, TP, or CBODu loads within the Basin if they are determined to not have any impact on the dissolved oxygen
levels in Aliceville Reservoir.
The TMDL is calculated by adding the aggregate allocation at the Mississippi border to the LA for the Coal Fire Creek watershed.
The WLA to the Alabama point sources and the LA to the other Alabama watersheds were not added in the TMDL calculation,
because their allocations are already reflected in the aggregate allocation to Mississippi.
Pollutant trading may occur between the loads allocated to nonpoint sources in Alabama and Mississippi if: (1) MDEQ and ADEM
agree to trade; and (2) such trading results in an overall 30% reduction of CBODu/TN/TP loads to Aliceville reservoir.
Table 2: OE/DO TMDLs and Reductions Necessary to Meet WQS in Aliceville Reservoir
as an Annual Average
Pollutant
CBODu
TN
TP
ALABAMA
Coal Fire Creek
Watershed
(HUC 3160106) 1'5
LA
30% reduction
(2,600 Ibs/day)
30% reduction
(29 Ibs/day)
30% reduction
(6 Ibs/day)
All other watersheds
(HUC 03160101, 03160103, and
03160105) 2'5
WLA
0% reduction
(0 Ibs/day)3
0% reduction
(0 Ibs/day)3
0% reduction
(0 Ibs/day)3
LA
30% reduction
30% reduction
30% reduction
MISSISSIPPI
Aggregate
allocation to
pollutants from
Mississippi at the
state border5
30% reduction
(181, 952 Ibs/day)
30% reduction
(16,311 Ibs/day)
30% reduction
(2,633 Ibs/day)
TMDL4
30% reduction
(184,552 Ibs/day)
30% reduction
(16,340 Ibs/day)
30% reduction
(2,639 Ibs/day)
The Coal Fire Creek watershed (HUC 03160106) is the only watershed in the Alabama portion of the Tombigbee River basin that
does not drain into Mississippi; therefore, loads from this watershed are not reflected in the aggregate allocation to Mississippi.
All other watersheds in Alabama (Bull Mountain Creek (03160101), Buttahatchee Creek (03160103), and Luxapallila Creek
(03160105)) drain from Alabama to Mississippi before ultimately draining back to Alabama and into Aliceville Reservoir. The
only point sources in Alabama discharge to these watersheds.
The wasteload allocation of 0 Ibs/day recognizes that there are currently no point sources in Alabama that impact dissolved oxygen
levels in Aliceville Reservoir. In order to be consistent with this wasteload allocation, any potential future discharges in Alabama
can only discharge TN, TP, or CBODu loads within the Basin if they are determined to not have any impact on the dissolved
oxygen levels in Aliceville Reservoir.
The TMDL is calculated by adding the aggregate allocation at the Mississippi border to the LA for the Coal Fire Creek watershed.
The WLA to the Alabama point sources and the LA to the other Alabama watersheds were not added in the TMDL calculation,
because their allocations are already reflected in the aggregate allocation to Mississippi.
Pollutant trading may occur between the loads allocated to nonpoint sources in Alabama and Mississippi if: (1) MDEQ and ADEM
agree to trade; and (2) such trading results in an overall 30% reduction of CBODu/TN/TP loads to Aliceville reservoir.
Prepared by US Environmental Protection Agency, Region 4
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Tombigbee River (Aliceville Reservoir) FINAL - Organic Enrichment/Dissolved Oxygen
2.0 Basis for the §303(d) Listing
Section 303(d) of the Clean Water Act (CWA), as amended by the Water Quality Act of
1987 and EPA's Water Quality Planning and Management Regulations [(Title 40 of the
Code of Federal Regulations (CFR), Part 130)], requires states to identify waterbodies
which are not meeting water quality standards applicable to their designated use
classifications. The identified waters are prioritized based on severity of pollution with
respect to designated use classifications. TMDLs for all pollutants causing violation of
applicable water quality standards are established for each identified water. Such loads
are established at levels necessary to implement the applicable water quality standards
with seasonal variations and margins of safety. The TMDL process establishes the
allowable loading of pollutants, or other quantifiable parameters for a waterbody, based
on the relationship between pollution sources and instream water quality conditions, so
that states can establish water-quality based controls to reduce pollution from both point
and non-point sources and restore and maintain the quality of their water resources
(USEPA, 1991).
Aliceville Reservoir, an impoundment of the Tombigbee River, is located in the Middle
Tombigbee-Lubbub hydrologic unit (HUC 03160106) in Pickens County, Alabama and
Lowndes County, Mississippi. The reservoir was formed by the closure of Tom Bevill
Dam in 1980 and is a part of the Tennessee-Tombigbee waterway. The State of Alabama
has identified the segment of the Tombigbee River from Bevill Dam upstream to the
Alabama/Mississippi state line (segment ID AL/03160106-0402-102), which is
coincident with the Alabama portion of Aliceville Reservoir, as being impaired by flow
alteration(s) and organic enrichment/low dissolved oxygen. The beneficial uses
identified by Alabama for Aliceville Reservoir are Fish and Wildlife and Swimming
(ADEM Admin. Code R. 335-6-11-.02), which jointly cover best usages including
propagation of aquatic life, contact and non-contact recreation, and fish consumption.
Aliceville Reservoir was originally placed on the 1996 § 303(d) list as not supporting
designated uses because water quality monitoring data collected in 1991 showed DO
concentrations less than 5 mg/L, and occasionally less than 4 mg/L. More recent data,
collected by ADEM in 1999, 2001, 2003 and 2006 and by EPA SESD in 2005, shows
that DO values in Aliceville Reservoir continue to drop below 5 mg/L. The listing has
been reported on Alabama's 1996 through 2008 § 303(d) lists of impaired waters. The
Tennessee-Tombigbee Waterway, which drains from Mississippi to Aliceville reservoir,
is not listed as impaired on the 2008 Mississippi § 303(d) List of Waterbodies.
Low dissolved oxygen concentrations are associated with "organic enrichment" - the
presence of excess amounts of oxygen-consuming organic matter. Water quality
problems are exacerbated by "flow alterations" - specifically the modifications to the
natural flow of the Tombigbee River associated with the construction of Bevill Dam,
which resulted in increased residence time, decreased velocity, and decreased reaeration
within this waterbody segment. Mitigation of flow alteration is not addressed in TMDLs
under current regulations.
Prepared by US Environmental Protection Agency, Region 4
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Tombigbee River (Aliceville Reservoir) FINAL - Organic Enrichment/Dissolved Oxygen
The purpose of this TMDL is to establish the acceptable loading of organic material from
all sources, such that the State of Alabama water quality criterion for dissolved oxygen is
not violated.
Usage of waters in the Fish and Wildlife classification is described in ADEM Admin.
Code R. 335-6-10-.09(5)(a), (b), (c), and (d).
a) Best usage of waters:
Fishing, propagation offish, aquatic life, and wildlife, and any other usage except
for swimming and water-contact sports or as a source of water supply for drinking
or food processing purposes.
b) Conditions related to best usage:
The waters will be suitable for fish, aquatic life and wildlife propagation. The
quality of salt and estuarine waters to which this classification is assigned will
also be suitable for the propagation of shrimp and crabs.
c) Other usage of waters:
It is recognized that the waters may be used for incidental water contact and
recreation during June through September, except that water contact is strongly
discouraged in the vicinity of discharges or other conditions beyond the control of
the Department or the Alabama Department of Public Health.
d) Conditions related to other usage:
The waters, under proper sanitary supervision by the controlling health
authorities, will meet accepted criteria of water quality for outdoor swimming
places and will be considered satisfactory for swimming and other whole body
water-contact sports.
Usage of waters in the Swimming classification is described in ADEM Admin.
Code R. 335-6-10-.09(3)(a) and (b).
a) Best usage of waters:
Swimming and other whole body water-contact sports. In assigning this
classification to waters intended for swimming and water-contact sports, the
Commission will take into consideration the relative proximity of discharges of
wastes and will recognize the potential hazards involved in locating swimming
Prepared by US Environmental Protection Agency, Region 4
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Tombigbee River (Aliceville Reservoir) FINAL - Organic Enrichment/Dissolved Oxygen
areas close to waste discharges. The Commission will not assign this
classification to waters, the bacterial quality of which is dependent upon adequate
disinfection of waste and where the interruption of such treatment would render
the water unsafe for bathing.
b) Conditions related to best usage:
The waters, under proper sanitary supervision by the controlling health
authorities, will meet accepted standards of water quality for outdoor swimming
places and will be considered satisfactory for swimming and other whole body
water-contact sports. The quality of waters will also be suitable for the
propagation of fish, wildlife and aquatic life. The quality of salt waters and
estuarine waters to which this classification is assigned will be suitable for the
propagation and harvesting of shrimp and crabs.
Alabama's water quality criteria for Fish and Wildlife and Swimming uses (ADEM
Admin. Code R. 335-6-10-.09-(5)(e)(4.) and Admin. Code R. 335-6-10-.09-(3)(c)(4.))
state that "for a diversified warm water biota, including game fish, daily dissolved
oxygen concentrations shall not be less than 5 mg/L at all times; except under extreme
conditions due to natural causes, it may range between 5 mg/L and 4 mg/L, provided that
the water quality is favorable in all other parameters. The normal seasonal and daily
fluctuations shall be maintained above these levels... In the application of dissolved
oxygen criteria referred to above, dissolved oxygen shall be measured at a depth of 5 feet
in waters 10 feet or greater in depth; and for those waters less than 10 feet in depth,
dissolved oxygen criteria will be applied at mid-depth."
ADEM's water quality standards applying to nutrients are narrative as stated in ADEM's
Administrative Code, Rule 335-6-10-.06:
The following minimum conditions are applicable to all State waters, at all places
and at all times, regardless of their uses:
(a) State waters shall be free from substances attributable to sewage, industrial
wastes or other wastes that settle in forming bottom deposits which are unsightly,
putrescent or interfere directly or indirectly with any classified water use.
(b) State waters shall be free from floating debris, oil, scum, and other floating
materials attributable to sewage, industrial wastes or other wastes in amounts
sufficient to be unsightly, or which interfere directly or indirectly with any
classified water use.
(c) State waters shall be free from substances attributable to sewage, industrial
wastes or other wastes in concentrations or combinations, which are toxic or
harmful to human, animal, or aquatic life to the extent commensurate with the
designated usage of such waters.
Prepared by US Environmental Protection Agency, Region 4
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Tombigbee River (Aliceville Reservoir) FINAL - Organic Enrichment/Dissolved Oxygen
3.0 Technical Basis for TMDL Development
3.1 Applicable Water Quality Criterion
As described in Section 2.0, the minimum dissolved oxygen (DO) concentration in a
stream classified as Fish and Wildlife or Swimming is 5 mg/L, except under extreme
conditions due to natural causes where a concentration of 4 mg/L will be allowed. The
target is established at a depth of 5 feet in water 10 feet or greater in depth; for those
waters less than 10 feet in depth, dissolved oxygen criteria are applied at mid-depth. The
target CBODu, TP and TN concentrations may not deplete the daily dissolved oxygen
concentration below this level as a result of the decaying process.
Aliceville Reservoir is classified for Fish and Wildlife and Swimming uses. For
navigation purposes, flows are controlled to maintain a minimum depth of 9 feet. Depths
at the downstream end of the listed reach, just above Aliceville Dam, remain greater than
10 feet. In sum, the primary water quality target is a DO concentration of 5 mg/L or
greater at a depth of approximately 5 feet.
3.2 Source Assessment
Both point and nonpoint sources may contribute external loads of BOD, TP and TN to a
given water body. These sources of organic enrichment may arise anywhere within the
upstream watershed, which constitutes an area of approximately 5,750 square miles in
Mississippi and Alabama and comprises six 8-digit USGS watersheds. These
watersheds, along with the major streams and rivers, are shown in Figure 1. Major point
sources of organic enrichment include wastewater treatment plants and paper mills, both
of which are present in the Tombigbee watershed. Potential nonpoint sources of organic
loading are numerous and often occur in combination. In rural areas, runoff can transport
significant loads of organic material from natural sources and agricultural lands, while
onsite wastewater (septic) systems can contribute a steady source of oxygen-consuming
wastes to groundwater. Nationwide, poorly treated municipal sewage comprises a major
source of organic compounds that decay and create additional organic loading. Urban
storm water runoff, wastewater treatment discharges, and sanitary sewer overflows can
also be significant sources of organic loading.
Prepared by US Environmental Protection Agency, Region 4
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Tombigbee River (Aliceville Reservoir)
FINAL - Organic Enrichment/Dissolved Oxygen
Tombigbee River |
Bull Mountain Creek |
20
20 40 Miles
Figure 1: Watersheds Upstream of Aliceville Reservoir
Internal sources of organic enrichment include the biomass of plankton and rooted
aquatic plants that grows in a waterway. Plants respire and consume oxygen, and dead
plant material is available for digestion by bacteria and zooplankton. However, plants
also produce oxygen as a byproduct of photosynthesis. During periods of active growth,
aquatic plants may provide a net positive contribution to dissolved oxygen on a daily
average basis. Elevated nutrient loads to a watershed may enhance the internal
production of organic enrichment.
Oxygen demand is also exerted by organisms that consume organic matter on and in the
sediments. The net impact of this process is known as sediment oxygen demand (SOD).
SOD arises from the deposition of organic matter to the sediments; it thus tends to reflect
a combination of the current and past history of external and internal sources of organic
enrichment.
Potential sources of organic loading in the watershed were identified based on an
evaluation of current land use/cover information (e.g., urban high density or forested
land) and an assessment of current NPDES dischargers to the watershed. The source
assessment was used as the basis of development of the model and ultimate analysis of
the TMDL allocations. Organic and nutrient loading within the watershed includes both
point and non-point sources.
Prepared by US Environmental Protection Agency, Region 4
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Tombigbee River (Aliceville Reservoir)
FINAL - Organic Enrichment/Dissolved Oxygen
3.2.1 Nonpoint Sources
Nonpoint source contributions of oxygen consuming wastes include runoff from various
landuses and septic systems. Landuse information was derived from the National Land
Cover Dataset (NLCD), 2001, and is presented in Figure 2. The predominant land uses
are forest (55 percent) and agriculture (31 percent). Of the agriculture, the bulk of which
is located in Mississippi, approximately 50 percent is pastureland and 50 percent is
cropland.
| | HUC 8 Watersheds
National Land Cover Class
^\ Open Water
^| Developed. Open Space
~^\ Developed. Low Intensity
| Developed. Medium Intensity
| Barren Land
^^| Unsolidated Shore
_] Deciduous Forest
| Evergreen Forest
~] Mixed Forest
j^B Dwarf Scrub
^] Grassland/Herbaceous
^^| Pasture/Hay
^^| Cultivated Crops
^m Forested Wetland
| | Scrub/Shrub Wetland
M
50
=i Miles
Figure 2: Land Use Classification in the Aliceville Reservoir Watershed
Watersheds 1 through 6 in Figure 2 correspond to the six 8-digit HUCs draining to
Aliceville Reservoir. Table 3 summarizes the land use distribution for each of these
watersheds.
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Tombigbee River (Aliceville Reservoir)
FINAL - Organic Enrichment/Dissolved Oxygen
Table 3: Landuse Distribution for Watersheds Draining to Aliceville Reservoir
(acres and percent)
ID
1
2
3
4
5
6
Watershed
Name/HUC
Upper
Tombigbee
03160101
Buttahatchee
03160103
Luxapallila
03160105
Town
03160102
Tibbee
03160104
Middle
Tombigbee
03160106
Total
Agriculture -
Cropland
163,641
(15.7%)
32,572
(5.8 %)
41,175
(8.1 %)
98,762
(22.2 %)
167,024
(23.7 %)
188,005
(18.0%)
691,179
(16.1 %)
Agriculture -
Pasture
170,037
(16.4%)
39,774
(7.1 %)
42,566
(8.4 %)
135,302
(30.4 %)
153,196
(21.8%)
134,216
(12.8%)
675,091
(15.7%)
Barren/
Mining
910
(0.1 %)
544
(0.1 %)
238
(0 %)
208
(0 %)
650
(0.1 %)
1,077
(0.1 %)
3,627
(0.1 %)
Forest
642,021
(61.7%)
408,270
(73.1 %)
364,342
(71.6%)
181,173
(40.8 %)
295,845
(42.0 %)
485,116
(46.4 %)
2,376,767
(55.3 %)
Transitional
38,760
(3.7 %)
27,322
(4.9 %)
13,278
(2.6 %)
2,032
(0.5 %)
7,987
(1.1 %)
18,909
(1.8%)
108,288
(2.5 %)
Urban
11,700
(1.1 %)
4,187
(0.7 %)
5,980
(1.2%)
15,809
(3.6 %)
8,333
(1.2%)
4,031
(0.4 %)
50,040
(1.2%)
Water/
Wetlands
12,686
(1.2%)
45,751
(8.2 %)
41,399
(8.1 %)
11,232
(2.5 %)
71,103
(10.1 %)
213,679
(20.4 %)
395,850
(9.2 %)
The predominant land use is forest, followed by agricultural. This watershed is primarily
rural, so agricultural loads of organic material during storm wash-off events could be
significant. Residential land uses constitute less than 1 percent of the watershed, and
loads from onsite wastewater disposal systems are unlikely to be significant relative to
other load sources.
3.2.2 Point Sources
ADEM and the Mississippi Department of Environmental Management (MDEQ)
maintain databases of current NPDES permits and GIS files that locate each permitted
outfall. These databases include municipal, semi-public/private, industrial, mining,
industrial storm water, and concentrated animal feeding operations (CAFOs) permits.
There are a total of 166 Mississippi and Alabama NPDES permits with BOD effluent
limitations in Tombigbee River HUCs 03160101 through 03160106 (USEPA PCS Query,
8/13/07). The majority of these permits are for small facilities.
There are ten major dischargers with BOD effluent limits within the six HUCs upstream
of Aliceville Reservoir. Two dischargers without BOD limits (EKA Chemical and
Sanderson) are also included because of proximity to the reservoir. EKA Chemical,
which manufactures hydrogen peroxide and sodium chlorate (according to MDEQ), has a
total organic carbon (TOC) limit from which BOD may be estimated. Sanderson
manufactures wood products and also reports its effluent BOD concentration. The two
major dischargers closest to Aliceville reservoir are Columbus POTW and Weyerhaeuser
Paper Mill. All dischargers are summarized in Table 4 and Figure 3.
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Table 4: Major NPDES Permitted Discharges of BOD to the Tombigbee River Upstream of
Aliceville Reservoir (HUCs 03160101 and 03160106)
NPDES
Permit #
MS0001783
MS0003158
MS0045489
MS0055581
AL0048372
MS0020788
MS0036111
AL0023400
MS0056472
MS0036412
MS0040215
MS0002216
Facility Name
Bryan Foods
True Temper
Sports/Emhart
Amory POTW
Aberdeen POTW
Hamilton POTW
West Point POTW
Tupelo POTW
Winfield POTW
Columbus POTW
Weyerhaeuser CPPC
EKA Chemical
Sanderson
Facility Type
Meat Packing
Plating
Sewerage
Sewerage
Sewerage
Sewerage
Sewerage
Sewerage
Sewerage
Paper Mill
Chemical
Wood Products
Flow
(MGD)
2.65 T
0.346 m
2
4
2.64 T
3.5
10.5
0.353T
10
19T
0.655 T
0.23 T
5- day BOD
Limit (Ib/d)
375 a
78b
751
1501,1001°
352
525'/876J
2,627
225 /183s
2,168
21,954°
32T
3.3T
Ammonia
(Ib/d)
50 / 44 n
0.033L
33K
58T
132
58K
175'/350J
76.7/49.2 3
500
192T
NA
NA
a. Pemitted CBOD5 limit.
b. No BOD5 limit for pipe 1; table shows average discharge from 8/05 to 12/06.
c. Permitted BOD5 limit was 1501 through Dec. 2004, then 1001 Jan. 2005 through present.
d. Variable limit based on temperature and flow conditions of the Tombigbee River, table shows monthly
average permitted discharge.
e. No BOD limit specified, has a permitted TOC limit of 73 Ib/d as of Nov. 2005.
f No permit limit; table shows average discharge from 1/03 to 12/06.
g. 2003-Aug. 2006 limit, then Sep. 2006 to present limit.
h. 2003-July. 2006 limit, then Aug. 2006 to present limit.
i. Summer limit (May - Oct..)
j. Winter limit (Nov. -Apr.).
k. Estimated ammonia from permitted discharge and assumed ammonia cone, of 2 mg/L.
1. Estimated ammonia from pipe #2 0.002 MGD discharge and assumed ammonia cone, of 2 mg/L.
m. Design flow.
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MISSISSIPPI
ALABAMA
I HUC 8 Watersheds
Streams
* Major BOD Dischargers
• Dams
Miles
Figure 3: Major Discharges of BOD to the Tombigbee River Above Aliceville Reservoir
Four major point sources in the watershed, indicated in red in Figure 3, contribute
oxygen-demanding wastes downstream of Stennis Dam and upstream of Bevill Dam.
These four dischargers closer to Aliceville reservoir have a combined BOD limit of 4,846
pounds per day and an ammonia limit of 692 pounds per day. Monthly discharge
monitoring report (DMR) data were obtained for Columbus POTW, Weyerhaeuser, EKA
Chemical and Sanderson.
The other eight of these major discharges are farther from Aliceville reservoir. Seven are
upstream of Stennis Lock and Dam at Columbus and one is far upstream on Luxapallila
Creek. These eight dischargers have a total BOD limit of 5,884 pounds per day and an
ammonia limit of 549 pounds per day. However, much of the distant discharged BOD
and nitrogen load is consumed or settled-out prior to reaching Aliceville Reservoir. The
loads from these facilities are a part of model boundary pollutant load conditions, and
these eight discharges are not explicitly in the model. To understand the contribution to
the boundary pollutant load from these facilities, load estimations outside of the water
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quality model were calculated. These estimations are based on distance from the model
boundary, flow velocity, and pollutant decay.
The BOD load delivered to the Aliceville pool from the distant, eight dischargers is
estimated to be about 33 percent of the actual discharged load due to decay. This
ultimately contributes only 1 percent of the total loading to the Aliceville reservoir.
These upstream major dischargers, as well as all minor permitted dischargers, are treated
as part of the headwater background load at Stennis Dam for modeling purposes.
Existing discharge data for the 12 major NPDES facilities in the watershed are included
in Table 5.
Table 5: Existing Discharge (2003-2006) for Major NPDES Facilities to the Tombigbee
River Upstream of Aliceville Dam
Facility Name
Bryan Foods
True Temper
Sports/Emhart
Amory POTW
Aberdeen POTW
Hamilton POTW
West Point POTW
Tupelo POTW
Winfield POTW
Columbus POTW
Weyerhaeuser CPPC
EKA Chemical
Sanderson
Facility Type
Meat Packing
Plating
Sewerage
Sewerage
Sewerage
Sewerage
Sewerage
Sewerage
Sewerage
Paper Mill
Chemical
Wood Products
5- day BOD
(Ibs/day)
51
78
108
188
25
66
584
22
245
2,659
32
3.3
Ammonia
(Ibs/day)
7
0.033
13
58
1.2
58
8
34
34
192
5.3
NA
TN
(Ibs/day)
1297
0
83
377
8
189
49
36
480
700
7.2
NA
TP
(Ibs/day)
598
14
54
32
64
17
353
5
65
191
7
NA
3.3 Data Availability and Analysis
A wide range of data and information were used to characterize the watershed and the
instream conditions. The categories of data used include physiographic data that describe
the physical conditions of the watershed, environmental monitoring data that identify
potential pollutant sources and their contribution, and instream water quality monitoring
data. This section presents the data sources considered and their use in TMDL
development.
3.3.1 Instream Water Quality
Water quality data from MDEQ, ADEM, Environmental Protection Agency Science and
Ecosystem Support Division (EPA SESD), and Weyerhaeuser Company was used to
characterize this reservoir and calibrate the models. A list of stations is shown in Table 6
and the locations are shown in Figure 4.
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Table 6: Water Quality Stations in Aliceville Reservoir
Station
1A
2A
3A
AVP01
AVP02
AVP03
CF025
JC315S
LC02
TT304
TT307
TT310
TT314
TT319
TT324
TT327
TT332
TT336
TT340
TTFA02S
327.8
327.0
316.3
308.1
1A
2A
Agency
ADEM
ADEM
ADEM
MDEQ
MDEQ
MDEQ
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
Weyerhaeuser
Weyerhaeuser
Weyerhaeuser
Weyerhaeuser
Weyerhaeuser
Weyerhaeuser
Station Name
Lower Aliceville Reservoir,
deepest point in main river
channel
Upper Aliceville Reservoir near
state line
Aliceville Reservoir Coal Fire
Creek Embayment
Aliceville pool at state line
Aliceville pool at Greens Creek
Aliceville pool below Luxapalilla
Creek
Coal Fire Creek
James Creek at Tenn-Tom
Waterway river mile 315.8
Luxapallila Creek near mouth
Tenn-Tom Waterway
downstream of Bevill Lock &
Dam
Tenn-Tom Waterway in Aliceville
Pool
Tenn-Tom Waterway near MS-
AL state line
Tenn-Tom Waterway near US 49
Bridge
Tenn-Tom Waterway near
Harrison Bend
Tenn-Tom Waterway below
Weyerhaeuser
Tenn-Tom Waterway above
Weyerhaeuser near marker buoy
Tenn-Tom Waterway near
Highway 82 Bridge
Columbus Pool nearStennis
Lock & Dam
Tenn-Tom Waterway near
Highway 50 Bridge
Tenn-Tom Waterway Flow
Augmentation Channel
Tenn-Tom at river mile 327.8
Tenn-Tom at river mile 327.0
Tenn-Tom at river mile 316.3
Tenn-Tom at river mile 308.1
ADEM station 1 A at Aliceville
Dam forebay
ADEM station 2A at state line
First Date
05/13/1992
04/19/2001
04/19/2001
06/24/2003
06/24/2003
06/24/2003
08/14/2005
08/13/2005
08/13/2005
08/15/2005
08/15/2005
08/15/2005
08/15/2005
08/13/2005
08/13/2005
08/13/2005
08/13/2005
08/11/2005
08/15/2005
08/11/2005
08/01/2003
08/01/2003
08/01/2003
08/01/2003
08/01/2003
08/01/2003
Last Date
10/31/2006
10/31/2006
10/31/2006
09/28/2004
11:30
09/28/2004
09/28/2004
08/16/2005
08/15/2005
08/15/2005
08/17/2005
08/17/2005
08/17/2005
08/17/2005
08/15/2005
08/15/2005
08/15/2005
08/15/2005
08/13/2005
08/17/2005
08/13/2005
1 0/24/2006
1 0/24/2006
1 0/24/2006
1 0/24/2006
10/24/2006
10/24/2006
#0bs
3,834
3,857
3,013
837
725
627
895
636
825
632
785
648
660
795
805
800
810
880
885
815
302
302
302
293
278
277
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Figure 4: Model of Aliceville Reservoir showing water quality monitoring stations
Based on monitoring conducted by ADEM during the past 5 years, the DO measured at a
depth of five feet at Aliceville Dam sagged each summer and fell below the water quality
standard of 5 mg/L in 2003, 2004 and 2006. The DO farther upstream at the stateline
followed a similar cycle with a summer sag, however it remained above 5 mg/L. A
detailed analysis of available data is provided in the "Aliceville Reservoir Low DO
Modeling Report, July 2008" (Modeling Report).
3.3.2 Other Available Data
Additional data sources were used to set-up the models. Sources included USGS
topographic maps, NHD area and waterbody GIS coverages, and US Army Corps of
Engineers shoreline coverages to define the model surface area and lay out the model
grid. Bathymetry for the Tombigbee River and Aliceville Reservoir collected by the US
Army Corps of Engineers and ADEM was used to define channel geometry for the
reservoir. Hourly flows from USGS gages downstream of Stennis Lock and Dam (USGS
02441390) and Bevill Lock and Dam (USGS 02444160), and daily flow for Luxapallila
Creek (USGS 2443500) were used to drive the hydraulics of the system. Surface water
elevation of the Aliceville pool from the US Army Corps of Engineers was used to
calibrate the EFDC model and correct the flows. The EFDC model volumes were also
compared to US Army Corps of Engineers storage volume to elevation tables for
Aliceville Reservoir to make sure the model represented this relationship.
EFDC and WASP require climate data that includes air temperature, relative humidity,
precipitation, barometric pressure, solar radiation and cloud cover. Climate data from the
Golden Triangle Regional Airport (WBAN 53893) station near Columbus, MS was used
in the models.
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4.0 Model Development
Establishing the relationship between instream water quality and source loading is an
important component of TMDL development. It allows the determination of the relative
contribution of sources to total pollutant loading, the linkage of loads to ambient impacts,
and evaluation of potential changes to water quality resulting from implementation of
various management options. The linkage relationship for a TMDL can be developed
using a variety of techniques ranging from qualitative assumptions based on scientific
principles to numerical computer modeling. For the Aliceville TMDL, qualitative
assumptions and quantitative models were used. This section describes the numerical
modeling techniques developed to simulate the loading of organic material and nutrients
and the resulting instream response of dissolved oxygen. Details on model calibration are
presented in the Modeling Report.
Two significant efforts have applied QUAL2E in the past to this section of the
Tombigbee River. Based on comments received, the model was redone to provide a
better representation of the reservoir. The modeling supporting this TMDL included a 3-
D hydrodynamic model, a watershed loading model, and an eutrophication water quality
model.
4.1 Environmental Fluid Dynamics Code (EFDC)
Environmental Fluid Dynamics Code (EFDC) was used to model three dimensional
hydrodynamics for Aliceville reservoir. The hydrodynamic model was setup as 113 grid
cells to accurately represent the Aliceville Reservoir and Tombigbee River system. The
cell size varies, but each is approximately 760 meters long (half a mile) and 280 meters
wide with an average area of 170,000 square meters. The model cells are shown in
Figure 4. Each segment was subdivided into one to five vertical layers based on the
normal depth; so deeper pools are divided into five layers and shallow river segments are
represented as a single layer. The EFDC model is used to simulate the dynamic flow and
water temperature from Stennis Lock and Dam to Bevill Lock and Dam and write this
information to a Water Quality Analysis Simulation Program (WASP) hydrodynamic
input file. More details about the development of this EFDC model of Aliceville
Reservoir can be found in the report "Tombigbee River and Aliceville Reservoir: Three
Dimensional Hydrodynamic Modeling Report" (Tetra Tech, 2007). This report covers
the initial setup and calibration of the Aliceville reservoir EFDC model for January 2003
through September 2005. For this TMDL, the EFDC model was expanded to include the
period to September 2006.
Through the hydrodynamic linkage file, the two models are linked and WASP computes
the water quality for each layer of each EFDC cell. EFDC and WASP were setup for
about 32 miles of the Tombigbee Waterway from Stennis Lock and Dam in Columbus,
Mississippi to the Aliceville Reservoir Pool impounded by Bevill Lock and Dam, in
Pickens, Alabama. The eutrophi cation module of WASP is then used to simulate
dissolved oxygen, nutrients, BOD and phytoplankton. The models were setup to simulate
the conditions from January 2003 to September 2006. This period represents the current
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pollutant loads discharged from point and non-point sources. It also includes periods of
wet, normal and dry precipitation patterns, that influence dissolved oxygen dynamics.
4.2 Water Quality Analysis Simulation Program (WASP)
The Water Quality Analysis Simulation Program (WASP) model was setup to evaluate
the effect of BOD, nutrients, algae, and other oxygen demanding substances on DO
processes. The Water Quality Analysis Simulation Program version 7 (WASP7) is an
enhancement of the original WASP (Di Toro et al., 1983; Connolly and Winfield, 1984;
Ambrose, R.B. et al., 1988). This model helps users interpret and predict water quality
responses to natural phenomena and man-made pollution for various pollution
management decisions. WASP7 is a dynamic compartment-modeling program for
aquatic systems, including both the water column and the underlying benthos. The
time-varying processes of advection, dispersion, point and diffuse mass loading, and
boundary exchange are represented in the basic program.
Water quality processes are represented in special kinetic subroutines that are either
chosen from a library or written by the user. WASP is structured to permit easy
substitution of kinetic subroutines into the overall package to form problem-specific
models. WASP7 comes with two such models — TOXI for toxicants and EUTRO for
conventional water quality. Earlier versions of WASP have been used to examine
eutrophication of Tampa Bay; phosphorus loading to Lake Okeechobee; eutrophication of
the Neuse River and estuary; eutrophi cation and PCB pollution of the Great Lakes,
eutrophi cation of the Potomac Estuary, kepone pollution of the James River Estuary,
volatile organic pollution of the Delaware Estuary, and heavy metal pollution of the Deep
River, North Carolina (Wool, et al., 2001). In addition to these, numerous applications
are listed in Di Toro et al., 1983.
The flexibility afforded by the Water Quality Analysis Simulation Program is unique.
WASP7 permits the modeler to structure one, two, and three-dimensional models; allows
the specification of time-variable exchange coefficients, advective flows, waste loads and
water quality boundary conditions. The eutrophi cation module of WASP7 was applied in
the development of these TMDLs.
4.3 Past QUAL2E Model Applications to the Tombigbee River
Two significant modeling efforts have been completed in the past on this section of the
Tombigbee River. Both of these efforts involved application of QUAL2E, which is a
one-dimensional steady-state modeling tool. Data and information from these models,
along with comments from the public, were considered in developing the EFDC/WASP
model used for this TMDL.
The first application was undertaken by Weyerhaeuser in 1987-1989. The modeling was
initiated in support of a proposed expansion of the Weyerhaeuser Columbus Mississippi
facility from 6 to 26 MGD, conversion to a kraft process, and relocation of the discharge
from Cedar Creek to the Tennessee-Tombigbee waterway (Weyerhaeuser, 1988).
Weyerhaeuser collected data during 1987, including dye studies for travel time and
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measurements of sediment oxygen demand, and built and calibrated a QUAL2E model
for the Tombigbee River between Stennis Lock and Dam at Columbus, Mississippi and a
point 4 miles below Bevill Lock and Dam (Aliceville Reservoir). The calibration
appeared to yield an adequate fit to observed data. Because of the large load from the
proposed discharge and the low assimilative capacity of the river under summer low flow
conditions, the modeling was used to develop a proposal for effluent limitations that
varied as a function of flow and temperature in the receiving water.
MDEQ and ADEM accepted the results of the Weyerhaeuser QUAL2E modeling and
MDEQ issued a NPDES permit to Weyerhaeuser containing the proposed variable
effluent limitations. EPA reviewed the permit in March of 1989 and submitted several
concerns. These prompted some minor revisions to the model and a variety of additional
runs and sensitivity analyses (Weyerhaeuser, 1989). The final effluent limitations in the
Weyerhaeuser permit were based on the 1989 modeling.
Another QUAL2E modeling effort, covering the entire Tennessee-Tombigbee waterway,
was conducted in the early 1990s. The Tombigbee River upstream of Bevill Dam,
including Aliceville Reservoir, is included in the Upper Tombigbee model (Shindala et
al., 1991). A second model was developed for the Tombigbee from Aliceville to
Gainesville, Alabama (Homan et al., 1995). The Upper Tombigbee model replaced
QUAL2E estimates of flow velocity with a proprietary linkage to a HEC-2 model.
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5.0 Development of Total Maximum Daily Load
This section presents the estimated TMDL developed for organic enrichment and
dissolved oxygen for Aliceville Reservoir. A TMDL is the total amount of a pollutant
that can be assimilated by the receiving water while still achieving water quality criteria,
in this case Alabama's water quality criteria for aquatic life. TMDLs can be expressed in
terms of mass per time or by other appropriate measures. TMDLs are comprised of the
sum of individual wasteload allocations (WLAs) for point sources, load allocations (LAs)
for nonpoint sources, and natural background levels. In addition, the TMDL must
include a margin of safely (MOS), either implicitly of explicitly, that accounts for the
uncertainty in the relationship between pollutant loads and the quality of the receiving
waterbody. Conceptually, this definition is denoted by the equation:
TMDL = Z WLAs + Z LAs + MOS
The TMDL is presented as a daily load in pounds of CBODu, TP and TN.
5.1 Numeric Targets for TMDL
TMDL endpoints represent the instream water quality targets used in quantifying TMDLs
and their individual components. For Aliceville Reservoir, the water quality target is
defined in terms of the Alabama water quality criterion for dissolved oxygen. As
discussed in Section 2.2, Alabama's water quality criteria state that,
"for a diversified warm water biota, including game fish, daily dissolved oxygen
concentrations shall not be less than 5 mg/L at all times; except under extreme
conditions due to natural causes, it may range between 5 mg/L and 4 mg/L,
provided that the water quality is favorable in all other parameters. The normal
seasonal and daily fluctuations shall be maintained above these levels... In the
application of dissolved oxygen criteria referred to above, dissolved oxygen shall
be measured at a depth of 5 feet in waters 10 feet or greater in depth; and for those
waters less than 10 feet in depth, dissolved oxygen criteria will be applied at mid-
depth."
In Aliceville Reservoir, the most severe dissolved oxygen depletion is observed
immediately above Bevill Dam. Water depth here is greater than 10 feet; therefore, the
critical point for application of the dissolved oxygen criterion is in the reservoir
immediately upstream of the dam, at a depth of 5 feet.
Critical conditions for application of the dissolved oxygen criterion are provided in
Section 5.3. Meeting the 5 mg/L criterion under critical flow and temperature conditions
ensures that the criterion will be met at all times throughout the year.
5.2 Existing Conditions
The calibrated water quality model provides the basis for performing the TMDL analysis.
The first step in the analysis is the simulation of baseline conditions. Baseline conditions
represent existing nonpoint source and NPDES discharge loading conditions and
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permitted point source discharge conditions. Table 7 below shows existing discharges
for the major NPDES permitted facilities upstream of Aliceville Dam.
Table 7: Existing Discharge (2003-2006) for Major NPDES Facilities
upstream of Aliceville Dam
Facility Name
Bryan Foods
True Temper
Sports/Emhart
Amory POTW
Aberdeen POTW
Hamilton POTW
West Point POTW
Tupelo POTW
Winfield POTW
Columbus POTW
Weyerhaeuser CPPC
EKA Chemical
Sanderson
Facility Type
Meat Packing
Plating
Sewerage
Sewerage
Sewerage
Sewerage
Sewerage
Sewerage
Sewerage
Paper Mill
Chemical
Wood Products
5- day
BOD
(Ibs/day)
51
78
108
188
25
66
584
22
245
2,659
32
3.3
Ammonia
(Ibs/day)
7
0.033
13
58
1.2
58
8
34
34
192
5.3
NA
TN
(Ibs/day)
1297
0
83
377
8
189
49
36
480
700
7.2
NA
TP
(Ibs/day
)
598
14
54
32
64
17
353
5
65
191
7
NA
The non-point source water quality loading from the tributaries was estimated with
BASINS PLOAD. Estimated BOD, nitrogen, and phosphorus loads for this section of the
Tombigbee River downstream of Stennis Dam at Columbus are shown in Table 8.
Details on how these values were calculated are included in the Modeling Report.
Table 8:
Estimated Nonpoint Source Loads from Stennis Dam to Bevill Dam
Parameter
BOD
TN
TP
Total Load in kg/year (and average Ibs/day)
1 ,225,874 (7404)
228,674(1381)
47,703 (288)
5.3 Critical Conditions
As discussed in Section 2.2, Alabama's water quality criteria for Fish and Wildlife and
Swimming uses (ADEM Admin. Code R. 335-6-10-.09-(5)(e)(4.) and Admin. Code R.
335-6-10-.09-(3)(c)(4.)) state that "for a diversified warm water biota, including game
fish, daily dissolved oxygen concentrations shall not be less than 5 mg/L at all times;
except under extreme conditions due to natural causes, it may range between 5 mg/L and
4 mg/L, provided that the water quality is favorable in all other parameters. The normal
seasonal and daily fluctuations shall be maintained above these levels... In the
application of dissolved oxygen criteria referred to above, dissolved oxygen shall be
measured at a depth of 5 feet in waters 10 feet or greater in depth; and for those waters
less than 10 feet in depth, dissolved oxygen criteria will be applied at mid-depth."
The critical conditions can be defined as the environmental conditions requiring the
largest reduction to meet standards. By achieving the reduction for critical conditions,
water quality criteria should be achieved during all times. The DO is lowest during
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summer conditions, which include low flows and high temperatures. The TMDL
addresses the worst summers in the 2003 through 2006 period.
Since Aliceville Reservoir is impaired for organic enrichment and low dissolved oxygen,
a number of processes that affect DO needed to be considered. These include BOD
discharged directly from facilities, SOD from the accumulation of organic material over
long periods of time, excess primary production resulting from excess available nutrients,
and aquatic plant management activities. Although low DO occurs during high
temperature, low flow conditions, when reaeration is minimal and retention times are
long, it should be kept in mind that this resultant low DO lags introduction of pollutants
in space and time. That fact must be considered when evaluating critical conditions. In
this case, the complex water quality issue was evaluated by simulating a four year period
containing wet, normal, and dry conditions. Both wet events and dry events were
analyzed in this Jan. 2003 through Aug. 2006 period.
5.4 Margin of Safety (MOS)
There are two methods for incorporating a Margin of Safety into a TMDL: 1) by
implicitly incorporating the MOS through use of conservative modeling assumptions in
the development of allocations, and 2) by explicitly specifying a portion of the TMDL as
the MOS based on an analysis of uncertainty in modeling results. The Aliceville TMDL
contains an implicit MOS that is obtained through conservative modeling assumptions,
including addressing the worst case conditions in the four year period from 2003 through
2006. In this TMDL the following information was considered in determining the margin
of safety.
• The worst case condition in the four year simulation from 2003 through
2006 was addressed to meet standards.
• Decreases in loads throughout the watershed due to other approved
TMDLs are expected to improve the DO at the model boundaries and
decrease the pollutant loads at the model boundaries.
• The model demonstrates that implementation of the TMDL will result in
average TN concentrations of 0.37 mg/L, which is less than the EPA
recommended ambient water quality criteria recommendations for lakes
and reservoirs in nutrient ecoregion IX (0.397 mg/L TN) (EPA, 1998).
5.5 Seasonal Variation
Seasonal variation is incorporated into the TMDL development because the models were
setup to simulate the conditions throughout each year from January 2003 to September
2006. This period represents the current pollutant loads discharged from point and non-
point sources. It also includes periods of wet, normal and dry precipitation patterns that
influence dissolved oxygen dynamics. Therefore, seasonal variation is incorporated into
the TMDL analysis in a manner that ensures year-round protection of water quality
standards.
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5.6 TMDL Results
In order to achieve the applicable water quality standards, the TMDL estimated by these
models requires a reduction of 30 percent from the total existing loads of CBODu, TN,
and TP that enter Aliceville Reservoir. The sources of CBODu, TN, and TP originate in
two states, Alabama and Mississippi. The TMDL is composed of three categories of
allocations: 1) a wasteload allocation for the point sources in Alabama; 2) a load
allocation for the nonpoint sources in Alabama; and 3) an aggregate allowable pollutant
load, which includes both the point and nonpoint contributions, to Mississippi sources in
the Tombigbee River watershed at the state border (see sections 3.2.1 and 3.2.2. for more
information).
The category of the load allocation for Alabama nonpoint sources is divided into two
subcategories to distinguish the nonpoint sources loads in Alabama that enter Mississippi
before ultimately draining back to Alabama across the state border. The load allocation
to the Coal Fire Creek watershed addresses nonpoint source loads that enter Aliceville
Reservoir without crossing into or out of Mississippi. The load allocation to all other
watersheds within Alabama (i.e., the Bull Mountain, Buttahatchee, and Luxapillila
watersheds) address loads from Alabama that drain into Mississippi before ultimately
draining back into Alabama across the state border. In addition, the Hamilton WWTP
and the Winfield WWTP discharge to the Buttahatchee and Luxapillila watersheds,
respectively; therefore, these wasteloads also drain to Mississippi before ultimately
draining back into Alabama across the state border. The distinction of Alabama loads
that enter Mississippi is important, because the aggregate allocation to pollutants from
Mississippi at the state border reflects some of the point and nonpoint source loads that
originate in Alabama.
Based on an analysis of the readily available data and information, the CBODu, TN, and
TP loads from the two existing point source facilities in Alabama (i.e., Hamilton WWTP
and Winfield WWTP) are determined not to have an impact on water quality in Aliceville
Reservoir. This determination is made in consideration of the magnitude of the loads
from these facilities, the fate and transport of such loads from the significant distance
upstream from Aliceville Reservoir, and analysis of water quality data in the
Buttahatchee Creek and Luxapalliala Creek watersheds. Therefore, these facilities are not
subject to the wasteload allocation.
The aggregate allocation to Mississippi reflects the allowable loads at the
Alabama/Mississippi border, rather than the allowable loads at their point of origin. The
loads and wasteloads upstream from the state border within both Mississippi and
Alabama will experience fate and transport processes through settling, decay, and
assimilation in the upstream waters before entering Aliceville Reservoir; therefore, the
sum of the loads from the point and nonpoint sources entering the watershed will be
greater in magnitude than the loads draining from Mississippi into Alabama at the state
line.
Although Aliceville Reservoir is not specifically identified as impaired for nutrients on
Alabama's § 303(d) list, reductions to TP and TN are necessary to meet a minimum DO
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concentration of 5 mg/L. Based upon information currently available, the reductions and
associated allocations for TP and TN are not expected to cause or contribute to
excursions of water quality standards to any downstream waterbodies.
Table 9 shows the maximum daily loads that will meet and maintain water quality
standards during the critical conditions experienced each summer (June - September).
Loads for non-summer months can be higher than those in , as long as the annual average
does not exceed the allocations in Table 10.
Table 9: OE/DO TMDLs and Reductions Necessary to Meet WQS in Aliceville Reservoir
(June - September)
Pollutant
CBODu
TN
TP
ALABAMA
Coal Fire Creek
Watershed
(HUC 3160106) 1'5
LA
30% reduction
(1,200lbs/day)
30% reduction
(17lbs/day)
30% reduction
(4 Ibs/day)
All other watersheds
(HUC 03160101, 03160103, and
03160105) 2'5
WLA
0% reduction
(0 Ibs/day)3
0% reduction
(0 Ibs/day)3
0% reduction
(0 Ibs/day)3
LA
30% reduction
30% reduction
30% reduction
MISSISSIPPI
Aggregate allocation to
pollutants from
Mississippi at the state
border5
30% reduction
(83,956 Ibs/day)
30% reduction
(9,606 Ibs/day)
30% reduction
(1,663 Ibs/day)
TMDL4
30% reduction
(85, 156 Ibs/day)
30% reduction
(9,623 Ibs/day)
30% reduction
(1,667 Ibs/day)
The Coal Fire Creek watershed (HUC 03160106) is the only watershed in the Alabama portion of the Tombigbee River basin
that does not drain into Mississippi; therefore, loads from this watershed are not reflected in the aggregate allocation to
Mississippi.
All other watersheds in Alabama (Bull Mountain Creek (03160101), Buttahatchee Creek (03160103), and Luxapallila Creek
(03160105)) drain from Alabama to Mississippi before ultimately draining back to Alabama and into Aliceville Reservoir. The
only point sources in Alabama discharge to these watersheds.
The wasteload allocation of 0 Ibs/day recognizes that there are currently no point sources in Alabama that impact dissolved
oxygen levels in Aliceville Reservoir. In order to be consistent with this wasteload allocation, any potential future discharges in
Alabama can only discharge TN, TP, or CBODu loads within the Basin if they are determined to not have any impact on the
dissolved oxygen levels in Aliceville Reservoir.
The TMDL is calculated by adding the aggregate allocation at the Mississippi border to the LA for the Coal Fire Creek
watershed. The WLA to the Alabama point sources and the LA to the other Alabama watersheds were not added in the TMDL
calculation, because their allocations are already reflected in the aggregate allocation to Mississippi.
Pollutant trading may occur between the loads allocated to nonpoint sources in Alabama and Mississippi if: (1) MDEQ and
ADEM agree to trade; and (2) such trading results in an overall 30% reduction of CBODu/TN/TP loads to Aliceville reservoir.
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Table 10: OE/DO TMDLs and Reductions Necessary to Meet WQS in Aliceville Reservoir
as an Annual Average
Pollutant
CBODu
TN
TP
ALABAMA
Coal Fire Creek
Watershed
(HUC 3160106) 1'5
LA
30% reduction
(2,600 Ibs/day)
30% reduction
(29 Ibs/day)
30% reduction
(6 Ibs/day)
All other watersheds
(HUC 03160101, 03160103, and
03160105) 2'5
WLA
0% reduction
(0 Ibs/day)3
0% reduction
(0 Ibs/day)3
0% reduction
(0 Ibs/day)3
LA
30% reduction
30% reduction
30% reduction
MISSISSIPPI
Aggregate
allocation to
pollutants from
Mississippi at the
state border 5
30% reduction
(181, 952 Ibs/day)
30% reduction
(16,311 Ibs/day)
30% reduction
(2,633 Ibs/day)
TMDL4
30% reduction
(184,552 Ibs/day)
30% reduction
(16, 340 Ibs/day)
30% reduction
(2,639 Ibs/day)
The Coal Fire Creek watershed (HUC 03160106) is the only watershed in the Alabama portion of the Tombigbee River basin
that does not drain into Mississippi; therefore, loads from this watershed are not reflected in the aggregate allocation to
Mississippi.
All other watersheds in Alabama (Bull Mountain Creek (03160101), Buttahatchee Creek (03160103), and Luxapallila Creek
(03160105)) drain from Alabama to Mississippi before ultimately draining back to Alabama and into Aliceville Reservoir. The
only point sources in Alabama discharge to these watersheds.
The wasteload allocation of 0 Ibs/day recognizes that there are currently no point sources in Alabama that impact dissolved
oxygen levels in Aliceville Reservoir. In order to be consistent with this wasteload allocation, any potential future discharges in
Alabama can only discharge TN, TP, or CBODu loads within the Basin if they are determined to not have any impact on the
dissolved oxygen levels in Aliceville Reservoir.
The TMDL is calculated by adding the aggregate allocation at the Mississippi border to the LA for the Coal Fire Creek
watershed. The WLA to the Alabama point sources and the LA to the other Alabama watersheds were not added in the TMDL
calculation, because their allocations are already reflected in the aggregate allocation to Mississippi.
Pollutant trading may occur between the loads allocated to nonpoint sources in Alabama and Mississippi if: (1) MDEQ and
ADEM agree to trade; and (2) such trading results in an overall 30% reduction of CBODu/TN/TP loads to Aliceville reservoir.
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6.0 Conclusions
The allocations described in this TMDL report will ensure protection of the applicable
water quality standards in Aliceville Reservoir. The State of Alabama is strongly
encouraged to continue proceeding with the development of numeric nutrient criteria for
all waters of the State, including Aliceville Reservoir. As part of this process, EPA
recommends that ADEM coordinate with MDEQ in conducting studies in order to verify
the allocations in the TMDL.
ADEM and MDEQ, through their NPDES permitting processes and nonpoint source
management programs, are strongly encouraged to develop a plan to implement the
TMDL. 40 CFR § 122.44(d)(l)(vii)(B) requires that NPDES permits should ensure that
water quality-based effluent limitations are consistent with the assumptions and
requirements of any applicable TMDL. MDEQ is encouraged to use the water quality
models referenced in this report and any additional data and information to implement the
aggregate allocation assigned at the Alabama/Mississippi border in a manner that ensures
compliance with 40 CFR § 122.44(d)(l)(vii)(B) and Alabama's applicable water quality
standards as expressed in this TMDL.
It is recommended that the Aliceville Reservoir watershed be considered a priority for
riparian buffer zone restoration and other nutrient reduction BMPs. The implementation
of these BMP activities should significantly reduce the nutrient load entering the river.
These activities, coupled with establishing appropriate water quality based limits
consistent with the TMDL, will provide improved water quality for the support of aquatic
life in the water bodies and should ensure the attainment of the applicable water quality
standards. As part of this process, MDEQ is encouraged to consider TN, TP, and CBOD
reductions identified in other TMDLs that it previously established for impaired waters in
the Tombigbee River basin.
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7.0 Public Participation
This TMDL was proposed for public review and comment for a 90-day period, beginning
October 31, 2007. EPA distributed information regarding the public notice of the TMDL
by e-mail to members of the public who have requested that ADEM and MDEQ include
them on a TMDL mailing list. The draft TMDL document was also available for review
on EPA Region 4's website: (http://www.epa.gov/Region4/water/tmdl/Alabama/).
All comments received during the public notice period are a part of the public record for
this TMDL. EPA has fully considered these comments as described in a responsiveness
summary, which is also part of the public record.
EPA acknowledges and appreciates the all of the comments, data, and information
provided by the members of the public, which added significant value to the process of
establishing this TMDL.
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8.0 References
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Environmental Protection Agency, Office of Water.
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the Upper Tennessee-Tombigbee Waterway. Submitted to the Tombigbee River
Valley Water Management District by Water Resources Research Institute,
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USEPA Region 4. June 7, 2007.
Thomann, R.V. and J.A. Mueller. 1987. Principles of Surface Water Quality Modeling
and Control. Harper & Row, New York.
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Weyerhaeuser. 1988. QUAL2E Model of the Tombigbee River below Stennis Lock and
Dam. Notebook submitted to Mississippi Bureau of Pollution Control by
Weyerhaeuser Paper Company, Columbus, MS, March 10, 1988.
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Bureau of Pollution Control by Weyerhaeuser Paper Company, Columbus, MS,
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Manual, U.S. Environmental Protection Agency - Region 4 Atlanta, GA.
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