Determining Cost-Effectiveness of Best Management Practices in Sustainable Watershed Management: A Decision-Making Tool for Restoring Bullrun Creek

Determining Cost-Effectiveness of Best Management Practices in Sustainable Watershed Management: A Decision-Making Tool for Restoring Bullrun Creek

Summary

Water quality in Bullrun Creek is listed as impaired by sedimentation, and has initiated a Total Maximum Daily Load program. Effective remediation requires the targeting of polluting sources and appropriate implementation of best management practices. Water samples and geographic data were analyzed and used to determine water quality improvements and as tools for prioritizing additional restoration projects. Preliminary sample analysis revealed general improvements in water quality. Spatial modeling provided additional data for water quality improvements based on land use changes. Multiple land use scenarios can be evaluated for cost to determine the most effective remediation plan for this creek.

Objectives/Performance Targets

The primary goal is to utilize illustrative data to develop appropriate BMPs for each target site, while maintaining economic feasibility. Effective watershed management regimes mandate cost-effective, goal-oriented and environmentally appropriate constructs to ensure realization of increased water quality. The objectives of the Bullrun watershed project include:

1.Water sample collection from eight sites in the watershed to be analyzed quarterly and following storm events in order to assess spatial and temporal trends for the entire watershed, and to assess the viability of existing restoration efforts.

2.Modeling of land-use changes to prioritize target restoration sites.

3.Evaluation and selection of varying BMP scenarios chosen for practicality, efficacy, cost-efficiency and overall optimality.

Accomplishments/Milestones

Water samples were collected quarterly from 8 sites and analyzed for quality parameters. Data collected in this study showed a decreasing trend in E.Coli and sediment when compared to samples collected two years prior. These results follow a series of land use improvements on multiple agricultural operations, largely in the form of pasture improvements and riparian buffer additions. Storm event samples showed a severe increase in transported sediment as compared to base flows, however. The amounts suggest erosional losses far above background losses for storm events, however, there is no background data available from the reference stream for this creek for storm events. E.Coli numbers were lower than previously sampled years as well. This may intuitively be linked to the improvements made on large animal operations, although there are far too many factors over a large spatial area to return any statistically significant correlation. Geographic modeling was run using the Integrated Pollutant Source Identification (IPSI) model developed by Tennessee Valley Authority engineers. This model replaced the Soil and Water Assessment Tool (SWAT) in this study due to the minimal amount of data available, and for the fact that other local streams modeled in IPSI provided frames of reference that assisted in model calibration efforts. IPSI is a USLE-based model that predicts that a majority of sediment losses in Bullrun Creek result from poor pasture conditions. Additionally, it supports the premise that recent water quality improvements are the result of pasture improvements as management practices. Multiple scenarios were modeled using IPSI, with a concentration on pasture improvements. Improvements of 50% were predicted to bring Bullrun Creek into compliance with TMDL standards. Cost listing was provided by the local NRCS and is being used to create a decision making matrix for optimal planning. The information will also be utilized in a Load Duration Curve assessment for pollutant loading analysis.

Impacts and Contributions/Outcomes

Water quality data was compiled and delivered to TVA for development of the Bullrun Creek Watershed Restoration Plan, as mandated for federal grants. Recommended management practices with an associated cost matrix were presented to the Bullrun Creek Task Force as a planning tool for future projects. The water quality sampling data will also be on record with the University of Tennessee and Tennessee Department of Environment and Conservation to provide temporal information on that creek for future analysis and planning endeavors.

Collaborators: