The battle of bacteria
Agencies, stakeholders focusing on restoring water quality
Story by Margaret Foust
Bacteria is the No. 1 pollutant of water in Texas, causing many of the state's water bodies to be placed on the Texas Water Quality Inventory and 303(d) List for failing to meet contact recreation use standards.
Across the state, agencies and local stakeholders are identifying the sources of pollution in bacteria-impaired water bodies and are developing management strategies to restore water quality and remove these water bodies from the impaired-water list.
In 2006 the Texas Commission on Environmental Quality (TCEQ) and the Texas State Soil and Water Conservation Board (TSSWCB) established the joint task force on Total Maximum Daily Loads (TMDLs). Chaired by then director of Texas Water Resources Institute (TWRI) Dr. Allan Jones, its goal was to identify the best and most cost-effective and time-efficient tools for developing bacteria TMDLs and TMDL implementation plans (I-Plans). The task force recommended a three-tier approach for stakeholders to use in implementing TMDLs. (See tier-approach).
This step-by-step tiered approach is incorporated into numerous TWRI bacteria-related projects.
The Improving Water Quality in Carters and Burton Creeks, funded by TCEQ, is developing a TMDL and TMDL I-Plan, using Tier 1 objectives, to reduce E. coli loading. The Texas Institute for Applied Environmental Research is providing technical support for the TMDL development for these creeks, located in central Brazos County, and TWRI is working with local watershed stakeholders to develop the TMDL I-Plan.
Projects in Attoyac Bayou, Lampass and Leon rivers, and Big Cypress Creek watersheds are following the Tier 1 and Tier 2 steps.
Project members of the Development of a Watershed Protection Plan for Attoyac Bayou are collecting water quality and stream-f low data, conducting a watershed source survey and developing a comprehensive GIS inventory, and analyzing water quality data using load duration curves and spatially explicit modeling. They are also conducting bacterial source tracking (BST) and evaluating the sources of E. coli that are contributing to the bayou's bacterial load. In addition, members are conducting a Recreational Use Attainability Analysis to determine the most appropriate water quality standard for the bayou, a subwatershed within the Upper Neches River Watershed.
Lucas Gregory, TWRI project manager, said local stakeholders are giving their input on possible sources contributing E. coli; collecting that information is a critical step in developing an effective watershed protection plan (WPP). TSSWCB funds the project through a Clean Water Act Nonpoint Source Grant from the U.S. Environmental Protection Agency (EPA).
In addition to the typical water quality data collection, Lampasas and Leon River Bacterial Source Tracking Assessment Project members are collecting bacteria from known animal feces to include in the Texas E. coli BST library, Gregory said. TSSWCB funds this project through its State General Nonpoint Source Grant Program.
The goal of Modeling Support and Bacterial Source Tracking for Big Cypress Creek Bacteria Assessment is to remove Big Cypress Creek, located in northeast Texas, and its tributaries, Tankersley and Hart creeks, from the state's impaired water list. TSSWCB funds this project from its TMDL general revenue fund.
A group of Big Cypress Creek Watershed stakeholders has learned about water quality rules and approaches to watershed planning and has expressed interest in addressing the bacterial impairments in the watershed, Berthold said. Through information gained from this project, they will decide to develop either a WPP or a TMDL and TMDL I-Plan, he said.
The institute recently finished three projects using Tier 2 steps that examined bacterial pollution in tributaries of the Little Brazos River in Robertson County. Findings will be presented to watershed stakeholders, who will determine the next steps in managing water quality in the tributaries.
The TMDL task force was also charged with developing a roadmap for scientific research on how bacteria behave under different conditions. Tailored to address some of the specific issues identified in the report, the project Fate and Transport of E. coli in Rural Texas Landscapes and Streams was initiated to better understand E. coli in the environment and evaluate better bacteria management strategies, Berthold said. TSSWCB is funding the project through a Clean Water Act Nonpoint Source Grant from EPA.
Through this project, team members are identifying, characterizing, and quantifying E. coli loading from various sources in an impaired watershed. Members are also monitoring bacteria survival, growth, regrowth, and die-off under different environmental conditions and monitoring re-suspension of E. coli in streams to test current assumptions regarding the fate and transport of bacteria in an environment and outside of the host animal.
"These areas being investigated are relative unknowns as far as understanding bacteria goes," Berthold said. "Information gleaned from this project will provide much needed information and will help improve modeling applications that are used to illustrate the transport of bacteria throughout a watershed and are dependent upon assumptions made regarding bacteria life cycles, their ability to survive and regenerate, and their impacts on water quality."
Recommendations of Bacterial TMDL Task Force
The Task Force recommended a three-tier approach to implementing bacteria TMDLs and I-Plans:
Tier 1 is a one-year process that includes the following steps:
- Form representative stakeholder group
- Develop comprehensive GIS of the watershed
- Survey potential bacterial sources
- Calculate load duration curves from existing monitoring data
- Analyze data collected by agency personnel and stakeholders
After reviewing information from Tier 1, the group may choose to complete and submit a draft TMDL for agency approval, request an evaluation of the designated use of the water body (a use attainability analysis), or proceed to Tier 2.
Tier 2 is a one- to two-year effort with the following steps:
- Collect targeted monitoring data to fill gaps in previously collected data
- Conduct qualitative library-independent BST and limited library-dependent BST analysis to determine whether humans and/or a few major classes of animals are sources
- Develop simple spatially explicit or mass balance models of bacteria in the watershed
- Analyze data
After analysis of Tier 1 and Tier 2 data, the group may chose to complete and submit the draft TMDL (or I-Plan if a TMDL was developed after Tier 1), request an evaluation of the designated use (an use attainability analysis), or initiate a "phased TMDL" and proceed with Tier 3 analysis.
Tier 3 is a two- to three-year process that includes:
- Continue strong stakeholder involvement
- Implement more extensive targeted monitoring
- Conduct quantitative library-dependent BST analysis
- Develop a detailed hydrologic/water quality model for the watershed
- Analyze data
Tier 3 should be implemented only when this level of detailed analysis is needed for I-Plan development or for TMDL development for particularly complex watersheds for which consensus cannot be reached after Tier 2.