Gilleland Creek: A TMDL Project for Bacteria
Gilleland Creek is a stream running through the Blackland Prairie region in northeast Travis County. In 2004, the Texas Commission on Environmental Quality placed Gilleland Creek on its list of impaired water bodies for elevated bacteria levels.
Section 303(d) of the federal Clean Water Act requires states to identify waters that do not or are not expected to meet applicable water quality standards. States are also required to develop a priority ranking for these waters taking into account the severity of the pollution and the designated use of the waters.
Remedial action is then required by the state to improve water quality in impaired streams and achieve compliance with water quality standards. TCEQ contracted with LCRA to develop a scientific model called a Total Maximum Daily Load (TMDL) study. The goal of this water quality study is to determine the sources that contribute to elevated levels of E. coli bacteria through water quality monitoring and guidance from Gilleland Creek Stakeholders.
In 2007, the TCEQ extended contractual agreements with LCRA to develop a TMDL Implementation Plan that puts the TMDL into action. The Plan will describe regulatory and voluntary actions that are necessary to reduce E. coli levels in Gilleland Creek. The Gilleland Creek TMDL Implementation Plan will include both point and nonpoint-source pollution controls.
This project marks the first step in the process to improve water quality of Gilleland Creek and comply with State and Federal laws.
WATERSHED FACTS:
Length: Approximately 32 miles
Watershed drainage area: About 76 square miles.
Flow: On average, 6.5 million gallons of water per day flows into the Colorado River just upstream of Webberville. A majority of the flow is contributed by six wastewater treatment plants that pipe treated wastewater to the creek.
Headwaters: Ward Spring, located northwest of Pflugerville.
Main tributaries: Harris Branch and Decker Creek.
Land use: Predominantly undeveloped or agricultural. Increasing residential development in the watershed seems to be negatively affecting water quality. The City of Pflugerville is located at the headwaters of the creek. Six municipal and two industrial TCEQ water quality permits are found in the watershed.
Segment: Gilleland Creek is also known as Segment 1428C. The State of Texas assigns tracking numbers to each water body as a management tool.