Comprehensive Sabine Watershed Management Plan Report
Table of Contents Section 10 - Water Quality and Environmental Issues

Executive Summary

1.0 Introduction

2.0 Water Needs

3.0 Existing Surface Water Supplies

4.0 Existing Ground Water Supplies

5.0 Comparison of Existing Supply and Projected Demand

6.0 Additional Supply from Water Conservation

7.0 Potential Surface Water Projects

8.0 Potential Ground Water Resources

9.0 Water and Wastewater Treatment Needs

10.0 Water Quality & Environmental Issues

10.1 SRA Water Quality Monitoring Program
10.2 Environmental Considerations and New Reservoir Developmen
t

11.0 Other Water Related Issues

12.0 Information Management and Public Participation

13.0 Recommendations

Appendices

List of Figures

List of Tables

10.1 SRA Water Quality Monitoring Program

SRA has been involved with water quality issues since 1954, when operational activities were initiated. During the 1960's SRA compiled all available water quality data for the Basin to aid the Texas Water Quality Board, the predecessor to the Texas Natural Resource Conservation Commission (TNRCC), in the establishment of the first water quality standards criteria in Texas. In 1972 the program was expanded to include Basin-wide ambient monitoring. Building on years of experience and detailed knowledge of the watershed, the SRA has successfully integrated its mission and existing watershed monitoring program with the watershed management process put forth by the Texas Clean Rivers Program CRP (CRP). SRA utilized the CRP to enhance its existing program and developed the subwatershed approach to water quality monitoring in the Basin, which has received statewide recognition. In September of 1998, the SRA received an exemplary rating by the TNRCC for its performance under the CRP. This section summarizes the SRA basin–wide monitoring plan with respect to its effectiveness in 1) addressing state and federal mandates and 2) identifying and addressing local water quality issues.

Figure 10.1
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10.1.1 SRA Monitoring Program

In order to meet the CRP requirements for water quality assessments within the Sabine River Basin, SRA has developed a comprehensive Basin-wide monitoring plan consisting of three major components: Water Quality Monitoring Program (WQMP), Subwatershed Monitoring Program, and Special Studies. Technical decisions and activities associated with water quality monitoring are carried out within the framework provided by the SRA Basin-wide monitoring plan. SRA managers using input from the SRA steering committee and CRP guidance documents make decisions regarding technical issues such as site selection and sampling regime. Figure 10.1 illustrates water quality monitoring sites located in the Sabine River watershed.

Figure 10.2
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The TNRCC’s surface water classifications, designated uses, and identification of threatened and impaired water bodies were used to evaluate the SRA monitoring plan and its effectiveness in addressing water resource management issues. The TNRCC divides streams, reservoirs, and lakes into geographic units called segments that are classified by the agency according to their quality, functions, and uses. The classifications assigned to each segment afford various levels of protection for water bodies through regulatory requirements and specific numeric water quality criteria. Figure 10.2 shows the relationships between the TNRCC’s classified segments and the SRA’s reaches and subwatersheds.

Based on regional assessments of each water body the TNRCC compiles a List of Impaired and Threatened Water Bodies in the state, also known as the State of Texas Clean Water Act (CWA) Section 303(d) List. Water bodies placed on the 303(d) list are subject to the development of a Total Maximum Daily Load (TMDL) under the CWA, as well as an evaluation of the appropriateness of existing segment criteria. In the Sabine Basin there are six water body segments identified on the 1998 303(d) list. According to the 1996 State of Texas Water Quality Inventory, one of these segments, Lake Tawakoni, continues to support all designated uses. Lake Tawakoni was placed on the 1998 303(d) list for atrazine in finished drinking water. The remaining segments on the 303(d) list do not support all designated uses, and include the Sabine River above Toledo Bend Reservoir, Toledo Bend Reservoir, Sabine River below Toledo Bend Reservoir, Adams Bayou (tidal) and Big Cow Creek. To address these water quality issues, SRA has focused a significant portion of their monitoring program on the identified segments. A total of 61 percent of the 102 water quality monitoring sites, and 50 percent of the 704 sampling events contained in the 1998-99 SRA Basin–wide monitoring plan are dedicated to collecting data from these five water bodies. Table 10.1 contains a summary of sampling activities associated with the SRA monitoring plan, the occurrence of water bodies on the 1998 303(d) list, and the support of designated uses for classified segments.

Table 10.1 Water Quality Monitoring Regime for 1998-99

Water Body

WQMP

SMP/Special Studies*

Water Quality
Management Issues

SRA Reach

Segments and (Tributaries)

Description

Sites

Samples

Sites

Samples

On 1998 303(d) list

Supporting All Designated Uses

1

501

Sabine River Tidal

3

36

 

 

no

yes

1

(501)

Tributaries to 501

2

24

 

 

n/a

n/a

2

503A

Sabine R. Below Toledo Bend Res. (Lower half)

1

12

 

 

yes

no

2

(503A)

Tributaries to 503A

 

 

1

4

n/a

n/a

3

503B

Sabine R. Below Toledo Bend Res. (Upper half)

2

24

 

 

yes

no

3

(503B)

Tributaries to 503B

1

12

 

 

n/a

n/a

4

504

Toledo Bend Reservoir

6

72

 

 

no

yes

4

(504)

Tributaries to 504

5

60

 

 

n/a

n/a

5

505

Sabine R. Above Toledo Bend Reservoir

6

72

 

 

yes

yes

6

506

Sabine R. Below Lake Tawakoni

2

24

 

 

no

yes

6

(506)

Tributaries to 506

 

 

6

24

n/a

n/a

7

507

Lake Tawakoni

3

36

 

 

yes

yes

7

(507)

Tributaries to 507

 

 

9

36

n/a

n/a

1

508

Adams Bayou Tidal

 

 

20

80

yes

no

1

511

Cow Bayou Tidal

 

 

29

116

no

no

6

512

Lake Fork Reservoir

3

36

 

 

no

yes

2

513

Big Cow Creek

1

12

 

 

yes

no

6

514

Big Sandy Creek

1

12

 

 

no

yes

6

515

Lake Fork Creek

1

12

 

 

no

yes

Total

37

444

65

260

 

 

   

n/a= Not Applicable

*SMP= Subwatershed Monitoring Program

10.1.2 Watershed Influences on Water Quality

The monitoring program used in the subwatershed approach designed by SRA, characterizes water quality at the smallest practical drainage areas within the Basin. Water quality data at this level are compared to land use and other watershed information to determine potential sources of contamination to water bodies.

SRA’s subwatershed approach takes into consideration the factors that place certain segments at risk for water quality concerns. These risk factors are determined from inventories of watershed activities and used to determine the overall risk of water quality impairment for each subwatershed. This information is then used in the decision making process for the allocation of future monitoring resources. The risk factors considered in the development of the subwatershed approach are: water quality, ambient toxicity, biological condition, superfund sites, permitted dischargers, cities with populations greater than 5,000, and landfills.

Figure 10.3
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Figure 10.4
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Effects of Land Use

To assess the effects of land use on water quality, a simple geographic information system (GIS) analysis was performed. Quantitative determinations of the percent cover by major land use categories (agricultural, forest, urban, water, and other) shown on Figure 10.3 were performed for each subwatershed. The land use data shown on Figure 10.3 was obtained from the Sabine River Authority’s current GIS database. SRA originally obtained the data from the Environmental Protection Agency (EPA). Note that the sudden discontinuities of land use south of Toledo Bend appear to represent problems with the data rather than actual changes in land use. Using SRA’s 1996 Regional Water Quality Assessment, the subwatersheds were grouped according to the type of water quality issue, either biological or physiochemical (Figure 10.4). The results of these analyses were then compared to determine potential relationships between land use coverage and water quality.

Figure 10.5: Land Use of Subwatersheds with Physiochemical Water Quality Issues

Subwatersheds are presented in order of decreasing water quality concerns.

The percent coverage by major land uses for subwatersheds identified with physiochemical water quality issues is illustrated on Figure 10.5. GIS analyses indicate that the major land use occurring in these subwatersheds is agriculture and that the degree of water quality concern appears to be directly related to the percent of agricultural use. Two of these subwatersheds, Caney/Timber Creeks and South Fork Sabine River, also have biological impairment concerns, but due to their physiochemical concerns and predominant agricultural land use they are discussed here. Nine of the 14 subwatersheds are located in areas either recently monitored or scheduled to be monitored by SRA under the Subwatershed Monitoring Program. As part of this program, water bodies are subject to a more intensive monitoring regime than the Basin-wide monitoring program (WQMP), including frequent water quality sampling, bioassessment, and ambient toxicity testing.

Figure 10.6: Land Use of Subwatersheds with Biological Water Quality Issues
Subwatersheds are presented in order of decreasing biological impairment concern.

Figure 10.6 illustrates the percent coverage by major land uses in subwatersheds identified as having biological impairment. The major land use category dominating the subwatersheds with biological impairment is forest. Urban land use is less than 10 percent in all but two subwatersheds, the Iron Bridge/Grace Creeks and Hawkins Creek subwatersheds, which receive drainage from the cities of Longview and White Oak. Although most of these subwatersheds are dominated by forested areas, the degree or occurrence of biological impairment does not appear to be related to any major land use category. Because of the lack of other water quality issues in these subwatersheds, it is possible that biological impairment is not being caused by any of the major contaminants analyzed under the SRA chemical monitoring program. This could indicate that one or more contaminants are present which have an ecological effect but may not be detectable under the current monitoring program design.

Effects of Landfills and Dischargers

A similar GIS subwatershed analysis was performed for landfills and TNRCC permitted dischargers. Figures 10.7 and 10.8 illustrate the locations of landfills and permitted dischargers in the Sabine River watershed. Geographically, the locations of landfills are fairly evenly distributed among all subwatersheds, with no apparent relationship between water quality issues and the number, type, or location of landfills.

Figure 10.8
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Figure 10.7
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It should be noted that the dairy discharge information contained in the TNRCC database reflects only information provided for permitted dairies and does not include dairies that are below the minimum size to require a discharge permit. The eight dairy discharge permits that are located in the Sabine River Basin are located in or near the Lake Fork watershed. Although few subwatersheds in this area are reported to have water quality concerns or potential concerns, the Lake Fork Reservoir watershed has been the focus of an ongoing effort by TNRCC and other agencies to control nonpoint source pollution from agricultural activities.

10.1.3 Recommendations for the SRA Water Quality Monitoring Program

The priorities associated with the SRA Water Quality Monitoring Program (WQMP) appear to be compatible with the priorities and assessment requirements of regional water planning districts, such as those formed by Senate Bill 1, and Clean Water Act mandates such as the TMDL program. Integration of these programs at the local level will provide the most efficient use of SRA resources for water quality protection.

Continued development of the SRA’s subwatershed approach, including the integration of water quality data with land use and point source information, will continue to provide the tools to make informed decisions about the quality of Sabine River watershed water resources. The local and regional processes that are in place should continue to actively support the Clean Rivers Program.

Watershed influences on water quality should continue to be a high priority in monitoring program design decisions. SRA should continue to use GIS technology to identify high priority areas as well as potential sources of water quality contamination. Existing Basin–wide land use databases are adequate for gross analyses but are inadequate at the subwatershed level. An effort to compile databases from all available sources that contain subwatershed-level information pertinent to the Sabine Basin would be a useful tool in the program design for future monitoring.

The current SRA monitoring program adequately characterizes baseline water quality conditions in the watershed, particularly in those areas included in the Subwatershed Monitoring Program. This approach identifies major contaminants and probable contaminant sources at the subwatershed level. Special Studies, the third major component of the program, are a useful addition to the monitoring program and can be used to incorporate high flow or storm sampling studies into the subwatershed studies where contaminants have been characterized and potential sources have been identified using the Subwatershed Monitoring Program. As an example, in rural areas sampling of storm runoff could be used to identify loadings from various parcels of land. This type of data could also be used by other agencies such as the Natural Resource Conservation Service in local non-point source demonstration projects within high priority watersheds. In urban areas, stormwater runoff data could be used by municipalities and industries to identify management practices or previously unknown problem areas that, if corrected, could improve the quality of the Sabine River. SRA could coordinate voluntary source identification surveys to better characterize unidentified water quality contaminants. Characterization of stormwater quality and watershed runoff is an essential part of the TMDL concept. Any special studies that may be developed to address local contaminant issues should be designed if appropriate to be of use in modeling efforts associated with future studies such as TMDLs or Source Water Protection Programs.

As evidenced by the analyses presented in this report, the use of bioassessments in the SRA monitoring program complements the routine chemical monitoring procedures. It is possible, however, that existing bioassessment data from the Sabine River watershed may provide more useful information at the subwatershed level if a more regional approach was used. For example, the existing biological data may provide more distinction between levels of water quality impacts if regional tolerance values or analytical methods developed for local eco-regions were employed. The use of bioassessment data in regional assessments will become more crucial as the TNRCC develops biocriteria and implements them in the water quality standards.

Another ecological concern related to water quality in the Sabine River watershed is the increase in aquatic vegetation in reservoirs and the introduction of exotic aquatic vegetation. Three species, water hyacinth, hydrilla and salvinia, are aggressive invaders which have also caused water use problems in other parts of the state and country. The TPWD is currently revising its Aquatic Vegetation Management Plan for Texas based on input from aquatic vegetation scientists and other experts from around the state, including SRA staff members. The plan will include recommendations to control excessive increases of exotic and endemic aquatic vegetation. SRA is addressing the problem by continuing to identify and reduce sources of contaminant loading to the Sabine Basin that affect natural balances. By reducing the disturbance of natural aquatic communities, the likelihood of excessive aquatic plant growth of any kind is reduced. SRA should continue to implement appropriate control measures for streams and reservoirs in accordance with the TPWD Aquatic Vegetation Management Plan.

10.2 Environmental Considerations and New Reservoir Development

Environmental considerations that have the potential to alter planned reservoir development in the Sabine Basin include issues relating to:

  • state and federally protected plant and animal species;
  • bottomland hardwood forests;
  • "waters of the United States", including wetlands and other special aquatic sites;
  • cultural resources; and
  • other protected areas. Protected areas include wildlife refuges, wetland mitigation banks, and conservation easements.

Complying with pertinent regulations requires extensive consultations and negotiations with state and federal regulatory agencies before a reservoir project would be approved. As part of the permitting process, issues such as threatened and endangered species, habitat protection, wetlands, and cultural resources would have to be addressed. An acceptable mitigation plan would have to be developed to compensate for unavoidable impacts. Major environmental issues that may affect proposed reservoirs in the Sabine Basin are discussed in the following sections.

Environmental Regulations

Due to the potential impacts of reservoir construction on the environment, water resource projects are regulated by a multitude of environmental laws. This section lists environmental rules that may apply to potential water resource projects in the Sabine Basin, including dams, reservoirs, canals, pump stations, aqueducts, wastewater re-use and aquifer recharge.

U.S. Army Corps of Engineers (COE)

  • Clean Water Act of 1972, Section 404 Permit The Clean Water Act applies to any action that adds dredge or fill material to Waters of the United States, including wetlands and non-navigable waters. New reservoirs in the Sabine Basin will require a 404 permit since they place a dam in waters of the United States. Canals, aqueducts or pipelines and levees may require 404 permits if they cross jurisdictional waters or wetlands.
  • Rivers and Harbors Act of 1899, Section 10 Permit Sections 9 and 10 of the Rivers and Harbors Act of 1899 affects all actions that may affect navigation in navigable waters of the United States, including dams, bridges, bulkheads, piers and docks. New reservoirs on major rivers in the Sabine Basin will require a Section 10 permit. This is usually applied for at the same time as the Section 404 permit. Navigable waters are subject to the Rivers and Harbors Act of 1899, which does not allow the construction of an obstruction within the waterway without Congressional approval. The main stem of the Sabine River below the confluence of Big Sandy Creek is considered navigable waters of the U.S.

U.S. Department of the Interior, Fish & Wildlife Service (USFWS)

  • Fish and Wildlife Coordination Act of 1966 The USFWS has the duty of reviewing and commenting on any action by another federal agency that affects natural resources such as fisheries, wildlife, and special habitats like wetlands. This is in addition to their specific regulatory requirements for endangered species, discussed below. Water resource projects in the Sabine Basin that affect wildlife habitats such as wetlands, bottomland hardwoods, free-flowing streams and mature forests would be subject to this Act.
  • Endangered Species Act of 1973, Section 7 Consultation and Section 10 Permit During coordination with the Fish & Wildlife Service, the agency may require a biological assessment under the Section 7 provisions of the Endangered Species Act. This report assesses the potential effects of a project on endangered or threatened species. If a project will affect, but not jeopardize, the existence of an endangered or threatened species, the project’s sponsor is required to obtain a Section 10 permit for incidental taking of endangered or threatened species before construction. Mitigation for the remaining population and habitat is often required as a condition of this permit. Coordination with the Fish and Wildlife Service for major water projects in the Sabine Basin would generally include a Section 7 biological assessment of endangered species and possibly mitigation.

U.S. Department of the Interior, Bureau of Reclamation

The U.S. Bureau of Reclamation is not a permitting agency but a sponsor of water resource projects, especially in the western states, that benefit agriculture and industry. Bureau of Reclamation-sponsored projects must comply with all federal, state and local permit requirements. They are generally authorized by specific appropriation from the U.S. Congress.

Federal Energy Regulatory Commission, Federal Power Act, License for Electric Generating Stations

The Federal Energy Regulatory Commission issues licenses to entities wishing to build power generating facilities that benefit the public. These projects often require an environmental impact statement and other approvals. Water resources projects in the Sabine Basin that include hydropower generation will require a license from the Federal Energy Regulatory Commission.

All Agencies, National Environmental Policy Act of 1969, Environmental Impact Assessment

Each federal agency has its own rules for implementing the National Environmental Policy Act, which requires major federal actions that significantly affect the environment to prepare an environmental impact statement describing the action and alternative actions, detailing the environmental impacts, and proposing mitigation measures to reduce or eliminate impacts. Federal actions may include direct construction, funding and approval of permits. Water resource projects in the Sabine Basin will involve federal actions such as permitting and may involve federal funding.

Texas Natural Resource Conservation Commission (TNRCC)

  • Water Rights Permit Chapter 11 of the Texas Water Code and Section 30 of the Texas Administrative Code require anyone wishing to divert, use, or store surface water, or to transfer surface water between Basins, to obtain a permit from the TNRCC. The permit application includes environmental, hydrologic and conservation assessments. Water resource projects in the Sabine Basin may involve modification of existing permits or creation of new permits which are subject to TNRCC’s assessment. The agency requires water conservation and drought contingency planning with all permit actions and may impose conditions for instream flow and water conservation. All applications for water rights that lie within 200 river miles of the coast must include an assessment of the right’s affect on bays and estuaries.
  • Clean Water Act of 1972, Section 401 Certification The Texas Natural Resource Conservation Commission must certify that each project that obtains a Section 404 permit by the Corps of Engineerswill not degrade water quality below state standards. The agency has recently issued draft guidance for implementing Section 401 certification. The guidance requires demonstrations from the applicant that the project has no practical alternative that would not affect the waters, and that losses of wetlands and waters have been avoided, minimized and mitigated in that order.
  • Clean Water Act of 1972, TPDES Discharge Permit The Texas Natural Resource Conservation Commission has recently been delegated authority to permit wastewater discharges under Section 402 of the Clean Water Act of 1972 from the United States Environmental Protection Agency. Anyone who discharges wastewater into the Sabine Basin requires a Texas Pollutant Discharge Elimination System permit from the TNRCC.

Texas Water Development Board (TWDB), Texas Water Plan Consistency

The TWDB provides funding assistance to water resource projects that are part of the Texas Water Plan, developed under Senate Bill 1, and are consistent with the plan’s goals. Water resources projects in the Sabine River Basin that are not in the plan or are inconsistent with the State Water Plan are unlikely to receive state funding.

Texas Parks & Wildlife Department (TPWD), Sand, Gravel and Marl Extraction Permit

All projects that involve excavation or removal of sand, gravel, or marl from state owned streambeds must have a permit from the Texas Parks & Wildlife Department. Water resources projects in the Sabine Basin will require a permit from the Texas Parks and Wildlife Department prior to start of construction once the Texas General Land Office (GLO) has determined that the impacted water course is state owned.

Texas General Land Office

  • Coastal Management Plan Consistency Determination All projects involving state and local permits or funding in the coastal counties of Texas must also be consistent with the Texas Coastal Management Plan. Water resources projects in Orange County in the Sabine Basin should also be reviewed for consistency with the Texas Coastal Management Plan as part of obtaining other permits to ensure that this process will go smoothly.
  • Grant of Easement All projects that cross or otherwise impact state owned waterways must obtain a Grant of Easement from the Texas General Land Office prior to start of construction.
  • Aquifer Recharge Rules Permitting authority for aquifer recharge resides with TNRCC. A Class V injection well permit would be required. If surface water is the source, a new or amended water right permit may also be required.

Municipal Zoning and Land Use Codes

Many cities in Texas have zoning and land use regulations that require project approval or permitting. Some water resources projects may not be initially consistent with local regulations and may require local approval of variances to local zoning or land use plans.

10.2.2 Existing Conditions

Threatened and Endangered Species

Federal and state lists of endangered and threatened species that are likely to occur in the counties where reservoir development is proposed are presented in this section. The locations of the six reservoirs analyzed in detail in Section 7 include portions of Rusk County (State Highway 322), Panola County (Carthage), Smith County (Waters Bluff and Prairie Creek), Upshur County (Big Sandy and Waters Bluff), Wood County (Big Sandy, Carl L. Estes, and Waters Bluff), Van Zandt County (Carl L. Estes), Rains County (Carl L. Estes), Gregg County (Prairie Creek and Carthage), and Harrison County (Carthage). Table 10.2 contains the names, protection status, and preferred habitats for each species according to the county lists published by the USFWS (USFWS, 1998) and the TPWD (TPWD, 1999). The county lists are not specific to individual reservoir sites, and a field survey to determine the presence or absence of species or habitats would be necessary if any of the recommended sites are selected for reservoir development.

Direct impacts of reservoir development on endangered and threatened species include flooding and removal of vegetation, and the potential for habitat fragmentation or isolation. Inundation of existing floodplains and the creation of open water habitat would decrease the habitat available for mammals, terrestrial snakes, and stream fishes, but would increase or enhance the habitat and forage area for other species such as birds, reptiles, and lake species of fish.

Table 10.2
Endangered and Threatened Species Potentially
Occurring in the Counties
of Proposed Reservoir Development

Click to view Table 10.2

10.2.3 Priority and Protected Areas

Wetland Mitigation Banks and Conservation Easements

Mitigation banks and conservation easements are two tools used to protect and preserve wetland and other natural resources. These areas are considered protected properties and are used in the screening of proposed reservoir sites in this report.

Wetland mitigation banking involves the creation, restoration, or increased protection of a functioning wetland to offset anticipated wetland impacts of the same habitat type, and was developed to expedite the regulatory approval process for mitigating wetland impacts. Mitigation banks were originally developed for entities, e.g. departments of transportation, repeatedly involved in projects resulting in wetland impacts. The mitigated impacts are generally for projects within the same watershed as the mitigation bank for cases where on-site or off-site in-kind compensation cannot be achieved or would not be as environmentally beneficial. Mitigation banks may be owned by either an agency or an individual and may be operated either for profit or as a not for profit endeavor.

Conservation easements are similar to mitigation banks in that they may be used as a conservation or preservation tool to preserve, protect, or enhance wetland and other natural resource areas. Conservation easements differ from mitigation banks in that the property owner legally (and voluntarily) restricts the type and amount of activity that may take place on their property. These easements may be managed by private land trusts, state entities such as the TPWD, or federal entities such as the USFWS or U.S. Department of Agriculture’s Natural Resource Conservation Service (NRCS). The restrictions of each easement are unique to the property and to the interests of the land owner, and are limiting to the degree that is necessary to protect the significant values of the property. The entity holding the easement is responsible for enforcing the easement restrictions.

Five wetland mitigation banks were identified in the Sabine Basin, encompassing a total of 10,189 acres of bottomland hardwood habitat. Two banks, the Anderson Tract Mitigation Bank and the Blue Elbow Swamp Mitigation Project, were established to compensate for future impacts to wetlands by Texas Department of Transportation construction activities. Others in the Sabine Basin include the Byrd Tract Mitigation Bank established by Enron Oil and Gas Company, the Klamm Mitigation Bank, and the Hawkins Mitigation Bank. One conservation easement was identified in the Sabine Basin and is owned by the Little Sandy Hunting and Fishing Club.

The Sabine Basin contains 12,675 acres protected by conservation easements. These easements are held by two conservation organizations - the Archeological Conservancy and the Texas Nature Conservancy (TNC), and two government agencies - the USFWS and NRCS.

Figure 10.9
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Evaluation of Three Potential Mitigation Banking Sites

The five wetland mitigation banks located in the Sabine River watershed cover 10,189 acres of bottomland hardwood habitat and comprise 54 percent of the statewide acreage of mitigation banks. These banks have shown, with varying degrees of success, that mitigation banks can be a useful tool for individuals, private industry, and agencies in the mitigation of impacts due to different types of development.

A screening study was performed to evaluate two areas in the Sabine Basin and one area in the Neches Basin regarding the suitability for development as wetland mitigation banks. Data were used to determine potential environmental and physical constraints to development of the three sites as wetland mitigation banks. Site locations are shown on Figure 10.9. These banks could be used by SRA to mitigate impacts of its actions to wetlands in the Sabine Basin.

The Toledo Bend Site is located upstream (north) of the northern reaches of Toledo Bend Reservoir in Panola County and contains approximately 8,063 acres. The Tawakoni Site is located downstream (south) of the Lake Tawakoni Dam in Rains and Van Zandt Counties and contains approximately 1,140 acres. The Bessie Heights Site is located on the northeast side of the Neches River in Orange County and contains approximately 400 acres. The SRA owns all three sites.

Factors used in the screening of these sites included the quality and quantity of existing wetlands, soil surveys and hydric soils list, degree of prior disturbance, frequency and duration of flooding, vegetation cover type, size of the area, proximity to other wetlands or water bodies.

The Toledo Bend and Tawakoni sites are located primarily in the floodplain and bottomlands of the Sabine River and are occupied by jurisdictional wetlands. Existing wetlands at these sites are high quality wetlands that could not be improved easily and would not generate substantial amounts of wetland credits above what they currently provide. For this reason, the Sabine River Authority would not receive many wetland credits while incurring substantial costs to develop most of these areas.

The Bessie Heights Site includes upland areas (and associated freshwater wetlands) that developed when dredge spoil from the Neches River was deposited in diked disposal areas, brackish wetlands along the estuary, and open water. The open water area is now part of the estuary to the east of the site and is associated with the Bessie Heights Oil and Gas Field. Construction of a mitigation bank on the spoil disposal areas of the Bessie Heights Site is feasible only on the areas that are close to the elevation of the surrounding water. This may not be desirable due to the difficulty of acquiring and permitting new spoil disposal areas. A mitigation bank at the Bessie Heights Site would be suitable for mitigating impacts to brackish marshes in the area, but not for mitigating impacts to bottomland hardwood forests elsewhere in the Sabine River Basin. Mitigation bank credits must generally be used for similar habitats in the same river Basin. Therefore, a wetland mitigation bank at Bessie Heights may not be very useful to SRA.

Figure 10.10
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Bottomland Hardwood Habitat (Floodplain)

Bottomland hardwood areas identified in the USFWS Bottomland Hardwood Preservation Program (USFWS, 1984) were used as a screening tool for potential environmental concerns at each proposed reservoir site. Other types of wildlife habitat may exist in the vicinity of the proposed reservoirs, but these were not specifically addressed. Figure 10.10 illustrates the proximity of the proposed reservoir sites to the USFWS-designated Priority 1 and Priority 2 bottomland hardwood areas.

Estimates of mitigation acreage and ratios for wildlife habitat losses were taken from intensive studies of the Waters Bluff site (TPWD, 1998) and the Big Sandy and Carl L. Estes sites (Frye & Curtis, 1990). Assessments of land cover and vegetation at these sites were performed using remotely sensed data (thematic mapping imagery and aerial photography) followed by agency field surveys. The quality of wildlife habitat at the Waters Bluff and the Carl L. Estes sites was evaluated using the Wildlife Habitat Appraisal Procedure (WHAP) (Frye, 1986), while the Big Sandy site was evaluated using the Habitat Evaluation Procedure (HEP) (USFWS, 1980). Habitat data for the remaining three reservoir sites (Carthage, Prairie Creek, and State Highway 322) were not available at the time of this report. More detailed analyses would be necessary to quantify available habitat and determine the extent of mitigation required for site development.

Table 10.3 includes a summary of each of the recommended reservoir sites with respect to the location of bottomland hardwood areas, wetland mitigation banks, known conservation easements, and estimated acreage of similar habitat that may be required for mitigation of impacts due to site development.

As evidenced by available information, four of the six proposed reservoir sites intersect with at least one USFWS priority bottomland hardwood area. Detailed habitat assessments of three of these sites (Waters Bluff, Big Sandy, and Carl L. Estes) have provided estimates of mitigation requirements under different management regimes. Mitigation requirements for the Carthage site were not available at the time of this report. Data identifying habitat at the Big Sandy and Carl L. Estes sites were collected in 1980 and may not reflect current conditions. Development of the Prairie Creek and State Highway 322 sites would not intersect any areas identified in the USFWS program, but could potentially impact other important areas of wildlife habitat. For specific sites targeted for development, updated habitat assessments should be performed to determine mitigation requirements for current habitat conditions.

Based on USFWS priority areas, current mitigation banks, and known conservation easements, development of the Waters Bluff site would impact the largest area and the greatest number of sites. Thirty nine percent of the proposed site (20,350 acres) would impact seven separate areas of concern, including two USFWS priority areas, four wetland mitigation banks, and one USFWS National Wildlife Refuge protected through a conservation easement. The extent of the proposed reservoir site and the high habitat quality assessed in 1997 (TPWD, 1998), combine to influence the mitigation requirements. The TPWD determined that between 141,575 and 566,039 acres of similar habitat would be required to mitigate the entire reservoir, depending on the intensity of the habitat management employed at the mitigation site. This acreage corresponds to mitigation ratios of between 4.5:1 and 18:1. According to the TPWD report, it is uncertain whether one or even several tracts could be found that could satisfactorily meet the mitigation requirements set forth for development of the Waters Bluff site. The significant mitigation requirement and a relatively great number of protected and priority areas would provide significant obstacles to development of the Waters Bluff site.

Table 10.3
Priority and Protected Areas Located at
Proposed Reservoir Sites and Estimated Mitigation

Click to view Table 10.3

Approximately 16 percent of the Carl L. Estes site is located on 4,659 acres of the Upper Sabine Bottom. A 1986 assessment of the Carl L. Estes site (TPWD, 1990) indicates that between 36,681 acres and 146,705 acres of similar habitat would be required to mitigate for the entire reservoir, depending on the level of management employed at the mitigation site. This corresponds to mitigation ratios ranging from 1.7:1 to 6.9:1. The same report used a 1980 assessment of the Big Sandy site to determine that between 5,359 and 21,344 acres would be required for mitigation of the entire reservoir (corresponding to a mitigation ratio range of 1.2:1 to 4.8:1). Approximately 52 percent of the Big Sandy site is located on 2,808 acres of the Upper Big Sandy Creek & Glade and the Lower Big Sandy Creek, USFWS priority bottomland hardwood areas.

The Carthage site is also located in an area identified in the USFWS program, with approximately 27 percent of the site located in the Lower Sabine Bottom. No previous assessments of the extent or quality of wildlife habitat have been performed for this site, therefore no estimates of mitigation requirements have been established.

Available data indicate that the Prairie Creek and State Highway 322 sites would not impact any USFWS priority areas, wetland mitigation banks, or known conservation easements. In the absence of habitat assessment data, it is not possible to estimate potential mitigation requirements for development of either of these sites.

Floodplain Hydrology

Reservoir construction results in the replacement of terrestrial and stream habitat with deep water habitat. Shallow water habitat area is increased along the perimeter of the reservoir and by the backwater effects along rivers and other tributaries. As an example, Toledo Bend Reservoir created approximately 1,200 miles of shoreline habitat. The effects of reservoirs on downstream floodplain hydrology and habitat are not as easily stated. Changes in the frequency and duration of downstream flood events may be expected after reservoir development. The degree of impact to floodplain hydrology and corresponding changes in vegetation, including bottomland hardwood forests, are determined by the magnitude and timing of releases from upstream reservoirs and the contribution of uncontrolled runoff from portions of the watershed below the reservoir.

10.2.4 Recommendations for New Reservoir Development

Development of a new reservoir takes considerable time and effort to avoid, minimize, and/or mitigate adverse environmental impacts so that the required permits and regulatory approvals are obtained. Therefore, a reservoir site with as few environmental concerns as practical should be selected.

Important environmental issues identified for the proposed reservoir sites include the following:

  • actual or potential presence of threatened or endangered species, and
  • presence of high value or protected lands such as wetlands, riparian bottomland hardwood forests, conservation easements, and mitigation banks.

These factors were used to rank the six proposed reservoir sites on a relative scale to provide an indication of environmental acceptability. Table 10.4 shows the relative level of environmental concern and the issues behind these concerns. Development of the Prairie Creek or State Highway 322 sites would provide the least impact to threatened and endangered species, existing mitigation banks and conservation easements, and identified bottomland hardwood forests. Although mitigation requirements have not been established for these sites, they would potentially incur less mitigation costs because of their relatively small acreage and fewer environmental concerns.

In addition to considerations for construction and permitting issues, plans for development of new reservoirs should include a strategy for reducing impacts to downstream hydrology and floodplain vegetation due to reservoir operations. To determine these potential impacts, data about the quality and quantity of existing communities and corresponding hydrologic requirements would need to be collected.

It is strongly recommended that new studies of floodplain vegetation and wildlife within the Sabine Basin be conducted. More current estimates of the quality, extent, and economic value of bottomland hardwood areas and threatened and endangered species, would play an important role in future planning activities of SRA.

Table 10.4 Relative Level of Environmental Concern Related to Proposed Reservoir Sites

Level of Concern


Reservoir


Issues

Highest

Lowest

Waters Bluff

greatest number of potential threatened and endangered species, conservation easements and mitigation banks, priority bottomland hardwood forests, and highest mitigation costs of any of the proposed reservoirs

Carl L. Estes

potential threatened and endangered species, priority bottomland hardwood forests, high cost of mitigation

Big Sandy

potential threatened and endangered species, priority bottomland hardwood forests, and high cost of mitigation

Carthage

potential threatened and endangered species, priority bottomland hardwood forests, and unknown cost of mitigation

State Highway 322

least number of potential threatened and endangered species and unknown cost of mitigation

Prairie Creek

potential threatened and endangered species, least acreage of any of the proposed sites, and unknown cost of mitigation