Navasota River Water Quality Improvement

Project Goals and Objectives:

  • Characterize the current bacteria loading and sources for the watershed and
  • Determine needed levels of bacteria reduction to meet applied water quality standards
  • Inform watershed stakeholders of water quality issues across the watershed
  • Work with stakeholders to select and prescribe management measures needed to improve water quality
  • Establish a comprehensive understanding of water quality across the Navasota River watershed


This project is designed to address bacterial impairments in the Navasota River Basin through a stakeholder driven process. In total, 12 individual bacteria impairments exist along the Navasota River and in some of its tributaries. To accomplish this, the Texas Water Resources Institute (TWRI) will initiate a stakeholder driven watershed planning process to develop strategies to effectively restore the waterbody to meet state water quality requirements. This approach will develop a better understanding of the hydrology, water quality, potential causes and sources for the impairment and will cultivate stakeholder ideas to include in the development of a watershed protection plan for the Navasota River Below Lake Limestone.

Education and outreach programs that focus on relevant water quality issues and watershed management practices will be delivered across the watershed to raise stakeholder awareness of water quality issues. Information regarding current water quality conditions across the watershed will also be discussed before the planning process begins. Local participation cornerstone of process as it is up to these same entities, groups and individuals to implement the WPP once completed and approved. To ensure this, TWRI will facilitate the development of an organized stakeholder group by working with landowners, public officials, special interest groups and agencies that have been identified as potential participants. Members of this group will be asked to provide guidance on pollutant sources assessments, establishment of water quality goals, and selection of management strategies during the development of the WPP. Routine stakeholder meetings and meetings with local soil and water conservation districts (SWCDs) will be held to ensure the continued engagement of stakeholders in the planning process.

A considerable amount of information regarding the Navasota River and its watershed has been produced over the years. This data will be collected and assessed to establish a comprehensive understanding of the watershed and its water quality. Information collected will also support the development of the WPP by providing much of the needed background information. TWRI will gather and utilize existing data and prior studies to identify water quality issues, characterize the watershed, identify potential sources of pollution, evaluate current loadings, establish needed loading reductions, and prioritize critical areas for implementation. Load duration curves (LDCs) are simple graphics that depict measured bacteria loads under varying flow conditions. They can help predict what types of pollutant may be causing water quality impairments and allow needed loading reductions at critical points in the watershed to be calculated. A geographic information system (GIS) of the watershed will also be developed and supplemented with stakeholder feedback to allow critical areas within the watershed needing specific management prescriptions to be identified systematically. 

Supplemental water quality monitoring will also be conducted. TWRI will conduct bi-weekly sampling and streamflow monitoring at a key index site for the waterbody (TCEQ Station 11785) for one year. Samples will be processed to determine E. coli and nutrient levels present in the waterbody. Streamflow measurements will also be collected simultaneously so pollutant loads can be calculated. This expanded data set will allow more accurate pollutant loading reduction estimates to be determined. Additionally, bacterial source tracking will be conducted on water samples collected at this site to help identify the sources contributing to the overall pollutant load in the river over the course of the year.  

Using information gleaned through this project, TWRI will work with stakeholders to develop a WPP that satisfies EPA’s 9 key elements of watershed based plans. In short, the developed WPP will clearly define pollutant sources and estimated loadings, will establish management recommendations and estimate their pollutant loading reductions. Additionally, the plan will also describe technical and financial assistance needs, an education plan, a project schedule with interim measurable milestones, indicators to measure progress and a long-term monitoring plan.

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