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TR-497

Navasota River Below Lake Limestone Watershed Protection Plan

L. Gregory, K. Lazar, A. Gitter

The Navasota River watershed is located in East-Central Texas in the Brazos River basin. Lake Limestone impounds the River causing a hydrological divide in the watershed. The majority of the watershed is rural and urbanization is largely confined to the Bryan/College Station area in Brazos County. Land use/land cover in the watershed is dominated by hay/pasture land and hardwood forests. Watershed characteristics and good land management yield a productive watershed that supports abundant livestock and wildlife.

The Navasota River and several tributaries were first listed as impaired on the 2002Texas Integrated Report (Texas 303(d) List)for elevated E. coli concentrations. Low dissolved oxygen (DO) in Duck Creek also resulted in a water quality impairment. Additionally, concerns for elevated nutrients and chlorophyll-a, and depressed DO also exist in several locations. These impairments and concerns signify the need to improve water quality and protect the resource for future uses and users.

To address this need, watershed stakeholders were organized to development the Navasota River Below Lake Limestone Watershed Protection Plan. Through this process, impairment causes and sources were identified and evaluated allowing stakeholders to make informed decisions regarding management recommendations to mitigate source contributions in a cost-effective manner. E. coli comes from numerous sources in the watershed; however, stakeholders recommended management strategies for five sources that can be feasibly managed. These include feral hogs, humans, livestock, pets, and stormwater.

Recommended management measures focus on preventing E. coli from entering waterbodies by retaining it on the landscape or removing it from the watershed. For livestock, this includes practices to modify where cattle are located in the watershed such as cross fencing to improve grazing management, providing alternative water sources, and prescribed grazing. For feral hogs, this includes reducing food supplies and physically removing hogs from the watershed. Pet focused management relies on proper disposal of pet waste. Human E. coli loading in watershed comes from failing on-site sewage facilities (OSSFs) and malfunctions in wastewater conveyance systems. To address these issues, replacing failing OSSFs and routine wastewater line inspections were recommended. Education outreach and delivery to raise awareness about water quality and how local actions affect the watershed is also recommended.

This plan outlines recommended strategies that will reduce potential pollutant loading to the Navasota River and its tributaries when implemented. However, watershed conditions change over time. To account for this, the WPP is a living document that will evolve as needed through an adaptive management process. Ultimately, the Navasota River Watershed Protection Plan sets forth an approach to improve watershed resource stewardship that allows watershed stakeholders to continue relying on the watershed as their livelihood while also helping to restore the quality of its water resources.

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