LAL receives contract to study nonpoint source pollution

In collaboration with the Southeast Tennessee Development District, the Landscape Analysis Lab is conducting a study to document potential nonpoint sources of E. coli in the Sequatchie River watershed. Stream segments of the Sequatchie River watershed are impaired due to high levels of E. coli pollution. Failures of on-site waste management systems and livestock access to streams have been identified as potential causes of high E. coli counts. This study will support the implementation of the Total Maximum Daily Load for E. coli (the sum of the individual wasteload allocations for point sources and load allocations for nonpoint sources) which was recently completed by the Tennessee Department of Environment and Conservation (TDEC) and approved by the U.S. Environmental Protection Agency (EPA).

Historical rural land use in the watershed was restricted to agriculture, mining, and limited residential development. Nonpoint sources of elevated E. coli levels were most likely caused by livestock contact with surface waters and failed municipal sewage treatment. However, with the influx of exurban/rural residential development and the divestiture of extensive privately owned lands by silviculture conglomerates, land use scenarios and new E. coli sources have rapidly evolved.

At present, there are numerous proposed developments on the Cumberland Plateau rim. The proposed developments bring multiple septic sewage treatment systems to an area noted for a high likelihood of karst topography and soils bearing poor percolation characteristics. The availability of extended water utilities could potentially spur increased residential development in the Plateau rim and highlands of the watershed; thereby, increasing the potential for E. coli release to surface waters. The future use of large tracts of privately owned silviculture property and current agricultural practices could greatly determine the integrity of the upper watershed water quality.

The LAL is developing a geospatial model describing current and potential future land use and cover conditions that may affect water quality in the Sequatchie River watershed. Both point and nonpoint sources will be examined. The GIS will be designed to support the implementation of the E. coli TMDL for the Sequatchie River watershed. Though generally useful geospatial data resources, such as additional land use data, will be created, the study will focus specifically on point and nonpoint sources of E. coli. E. coli nonpoint sources may be inferred from ground conditions associated with current and proposed land use scenarios.

An analysis of current and potential land use and cover conditions will identify areas of concern (AOCs) within the watershed. Tax parcel data and information from regional planning assessments will be combined with existing and derived topographic, geographic, and hydrographic spatial datasets to create a GIS for the Sequatchie watershed to identify AOCs for water quality protection within the Sequatchie River watershed.

This investigation will provide WPC with updated source information, digital documentation of TMDL applicable geospatial data resources describing current and potential future land use and cover conditions. The format of the documentation and deliverables will be such that it can easily compliment a TMDL index for a final report. The ability to identify potentially impacted watershed regions not only serves as a proactive measure for long term quality and enhancement in the watershed, but also enhances the survey of all pertinent water quality information required to implement a TMDL. Beyond development of these products, the project team will engage local planning entities and watershed groups to promote water quality protection in the region. The methods used to develop these resources, and deliver the results to the WPC and to local groups will be a model for similar efforts in other watersheds in Tennessee.

Links

Southeast Tennessee Development District - Focused on cost effectively plan, promote and implement programs that result in the development and improvement throughout the southeast region of the Tennessee River Valley Basin.

EPA 303(d) List of impaired waterbodies document - An EPA approved final list of streams, rivers, reservoirs, and lakes that do not meet water quality standards in 2008. Provides pollutant information and TMDL prioritization.

EPA-Approved TMDLs Arranged by Watershed - A list of completed TMDLs for Tennessee that have been approved by EPA.