Water Quality
Stream Segment Description
Beginning near Kyle in eastern Hays County, Plum Creek flows 52 miles (84 km) before its confluence with the San Marcos River south of Luling. Plum Creek is fed by many small streams and tributaries, including Porter Creek, Brushy Creek, Elm Branch, Dry Creek, and West and Clear Forks. The slope is gentle, as the stream falls only 425’ (130m) over its 52 miles. Though some downcutting has occurred, there are no known significant alterations to the stream channel. The stream contains a series of pools in the lower portion of the drainage, resulting in slower flows and low levels of dissolved oxygen (Texas Water Commission 1991).
The mainstem of Plum Creek, classified as Segment 1810 by the TCEQ, includes Plum Creek from FM 2770 in southeastern Hays County to the San Marcos River. It has been designated for high aquatic life, contact recreation, general, and fish consumption uses. The stream currently has 3 routine water quality monitoring stations. Stations 17406 on Plum Creek Road near Uhland and 12640 on Caldwell County Road 135 near Luling are monitored monthly by the Guadalupe-Blanco River Authority (GBRA). Station 12647 is located one mile south of Caldwell County Road 202 near Lockhart and is monitored quarterly by the TCEQ. These stations and a number of temporary monitoring sites are used to track the quality of water in Plum Creek.
Plum Creek was historically a shallow, intermittent stream that ran dry in times of drought and during summer but flowed during significant rainfall events. Two US Geological Survey (USGS) gages on Plum Creek (08172400 near Lockhart and 8173000 near Luling) monitor streamflows. Before urban development, Plum Creek above Lockhart ran dry almost every year, and that portion of the creek was mostly driven by rainfall and runoff. Southern reaches of Plum Creek, particularly south of Lockhart, were and continue to be fed by a number of small springs that flow throughout the year. Due to the construction of wastewater treatment plants and the resulting flows from them, Plum Creek now flows year-round over almost its entire length.
Water Quality Assessment
Plum Creek (Segment 1810) exhibits high nutrient (nitrogen and phosphorus) concentrations and is impaired by high E. coli bacteria levels. According to the Texas Water Quality Inventory and 303(d) List, Plum Creek does not support contact recreation.