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WWRC 97-05jjj
The Total Maximum Daily Load (TMDL) Issue in Wyoming

Abstract

To respond to this lawsuit and maintain state control over water quality programs and regulation in Wyoming, the Department of Environmental Quality (DEQ) is restructuring its Water Quality Division to specifically address the 303(d), or TMDL, issue. The point source and non-point source programs are combining into a watershed protection and management program to better enable existing programs to incorporate TMDL concerns. Existing resources and additional positions are also being added to the program to address the TMDL concerns.

The TMDL process relies on quality controlled monitoring and assessment of individual water bodies or watersheds, so quantifiable water quality goals, or endpoints can be established to allow water bodies to meet their designated uses. Only then can TMDLs be developed for each pollutant that may be adversely affecting beneficial uses of a stream. TMDLs can be either the amount that a specific pollutant needs to be reduced, or the maximum loading of that pollutant, which will allow the TMDL endpoints to be met. A TMDL consists of Waste Load Allocations (WLAs) for point source dischargers and Load Allocations (LAs) for nonpoint sources (NPS) of pollution, along with a margin of safety.

Waste Load Allocations are developed based on models and water quality standards. They are regulated through discharge permits, and are usually in the form of effluent flow and concentration limits such as pounds per day or mg/L. LAs must incorporate natural, background loading of a pollutant as well as human induced sources. Since it is usually very expensive and time consuming to quantify NFS pollution in terms of concentration in water, such as mg/L, LAs are often based on other quantifiable parameters such as habitat or stream condition (i.e. 50% reduction in cobble embeddedness, 75% reduction in average annual bank erosion, etc.). When LAs are determined. Best Management Practices (BMPs) are also suggested so the LAs and TMDLs can be met. BMPs can be land management changes such as changing grazing strategies, using different timber harvesting methods or reducing miles of roads in a watershed. Implementing BMPs for NPS pollutants is strictly voluntary, and neither DEQ nor EPA has regulatory authority to require land management changes.

Since the majority of stream impairments in Wyoming are due to NPS pollution, which does not begin nor stop at property lines, all land owners and land managers in a watershed must be involved and work cooperatively to improve water quality. Local support and input from citizens, land owners, Conservation Districts and County Extension Agents is critical because these groups have demonstrated strong commitment to reduce NPS pollution at the local level through proactive voluntary management changes implemented in 319 water quality improvement projects. Public comment will be solicited and utilized throughout the TMDL process.

Wyoming's TMDL Work Plan has three primary goals: to accurately assess the streams and lakes of the state for water quality impairments; to confirm stream designation for beneficial uses; and to develop TMDLs for those water bodies which need them. Both of these goals rely on accurate water quality assessment, but although many water studies have been conducted in Wyoming, the use of different methodology between studies often does not allow direct comparisons of data collected in different water bodies, or provide the necessary data to develop TMDLs. In several cases, differing methodology has led to the improper listing, or not listing, of streams on the 303(d) list of streams scheduled for TMDL development. Therefore, stream assessment and TMDL development will require the use of consistent methodology throughout the state.

Fortunately, DEQ began the statewide Reference Stream Project (RSP) in 1992 to assess the water quality of streams throughout the state, using the same methodology so comparisons could be made between streams. RSP monitoring will be conducted on over 200 streams by the end of 1997, so DEQ will have a complete database to make comparisons with. RSP is based on analysis of benthic macroinvertebrate community structure (bioassessments) as the primary indicator of water quality and ecological integrity of streams. Benthic macroinvertebrates are exposed to all water quality changes in a stream, both short and long term, and since certain species are more tolerant of certain pollutants than others, community structure is highly dependent on year-round water quality. Therefore, bioassessments have been used throughout the U.S. to quantitatively evaluate water quality changes related to a wide variety of point source and NPS pollutants, as well as land use changes. Standard RSP monitoring includes bioassessments incorporated with sampling for 12 water quality parameters, flow measurements, stream channel classification, 13 qualitative habitat parameters and 6 quantitative habitat parameters.

A major problem when assessing NPS pollution is distinguishing between pollution caused human activities and materials, such as sediment or nutrients, which occur naturally in a stream due to background sources. The RSP identifies impaired and least impaired streams, and stratifies them by ecoregion and by Rosgen stream classification. This allows formulation of realistic goals, objectives and end points for TMDL development by accounting for natural water quality and biological variability due to regional differences in soils, climate, hydrology, and geochemical and geomorphological processes.

The Department of Environmental Quality proposes a two phase monitoring approach for TMDL development and implementation, based on the prioritized 303(d) list. The first monitoring phase will be the Beneficial Use Reconnaissance Project (BURP). BURP monitoring will be conducted at each impaired stream segment on the 303(d) list, following RSP protocols. Additional monitoring parameters may be included, based on site-specific pollutants suspected during reconnaissance, in order to enhance detection of pollutants and increase sensitivity of the assessment. For example, metals may be sampled at streams affected by mining activity, or oil & grease and Total Radium 226 may be sampled at streams affected by oil and gas production.

The BURP is intended to differentiate between impaired and non-impaired streams, based on attainment of beneficial uses. It is not intended to identify every source of NPS pollution, but it may be possible to suggest causative agents through an evaluation of all existing data and other supporting evidence. Data generated from BURP monitoring will also supplement existing data for use in models to set, or modify, WLAs for streams which receive point source discharges. BURP monitoring should be sufficient to analyze streams which are not impaired by NPS pollutants. BURP monitoring will provide baseline data for more intensive sampling and TMDL development in Phase II, or to change the classification of streams which do not have the natural water quality to support their designated beneficial uses.

Streams meeting beneficial uses will go to public comment for delisting from the 303(d) list, while streams which are only impaired due to point source discharges will continue in the BURP process to determine effectiveness ofWLAs. However, streams impacted by NFS pollutants, will progress to the second monitoring phase, the TMDL Sampling and Analysis Plan (SAP), due to the complexity of quantifying NPS pollutants and sources. The SAP is the site-specific monitoring and analysis plan designed to establish LAs, identify appropriate BMPs, and determine effectiveness ofTMDLs toward restoration of beneficial uses.

No single set of monitoring parameters and no single monitoring design can be applied to all Impaired streams because of the wide variety of NPS pollutants, NPS pollutant sources, land uses and their varying effect on beneficial uses. Moreover, no single set of BMPs that implement the TMDL will be effective for restoration of water quality, habitat and biological integrity at all NPS impaired streams. Therefore individual SAPs, LAs, BMPs and TMDL endpoints will need to be developed for each stream segment or watershed impaired by NPS pollutants, with extensive public involvement throughout the process.

Each SAP design will incorporate water quality, biological and habitat monitoring to assess site-specific pollution sources, type of pollutants and TMDL endpoints defined for restoration of beneficial uses. Watershed size, access to sampling sites, size of stream segment, location of flow diversions, tributaries, change in land use, stream classification, geomorphology and other features also factor into the SAP design. Site-specific reference streams will be incorporated into the SAP design when possible. Reference streams are identified either within the same, or a nearby, drainage as the impaired segment and are sampled during the same time period as the study site. This design accounts for variability affecting water quality such as temperature, precipitation, stream flow, local geology, wildlife activity and other natural variables. The advantage of the reference stream design is that it provides information for establishing measurable objectives and endpoints on a site-specific or watershed basis, based on achieving conditions similar to the reference site.

Data from SAP monitoring will be assessed and TMDL endpoints established to address the pollutants of concern. Then, TMDLs will be established for each pollutant, and LAs will be calculated for different sources and/or stream reaches in order for the stream to meet its TMDLs. Unlike WLAs, which are usually concentration based standards, LAs and TMDLs are often measures which quantify habitat or stream condition. In order to meet LAs and TMDL endpoints, BMPs will be suggested to reduce NPS pollution. Because compliance with nonpoint TMDLs is voluntary, implementation of BMPs will be left up to individual land owners or managers. However, there may be incentive programs that can assist land managers with the implementation ofBMPs. Through public participation and cooperation in the TMDL process, it is the hope of the DEQ that land managers will see the value of implementing BMPs and modifying land management practices in order to protect and restore waters of the state, while maintaining productivity of the land.

Following TMDL development and BMP implementation, monitoring intensity may be reduced for a period of time to allow the BMPs to take effect and give the stream time to recover. After the "recovery period", BURP or SAP level sampling, as decided on a case by case basis, will resume to determine if the stream is meeting its beneficial uses.

However, if beneficial use has not been attained, the BMPs and TMDLs for the stream will be investigated, with public comment, to determine what changes are needed for stream rehabilitation.

Quality Assurance / Quality Control (QA/QC) functions ensure that all data generated during monitoring is consistent, valid and of known quality by following approved and specific field, laboratory and data handling methods. BURP monitoring and SAP monitoring will follow QA/QC guidelines established for Wyoming point source and NPS water quality monitoring. The QA/QC guidelines ensure consistency for field and laboratory functions to guarantee quality data and thus, sound TMDL development and implementation.

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