HYDROGEOCHEMICAL STUDY OF URBAN MAN-MADE LAKES (JIM BERTRAM LAKE SYSTEM) IN LUBBOCK, TEXAS

The Jim Bertram Lake System (JBLS) in Lubbock, Texas is a series of six man-made lakes extending from the northern to the southeast region of the city. The lakes were constructed in the 1970s along ephemeral streams of Yellow House Draw and North Double Mountain Fork of the Brazos River, utilizing secondary wastewater effluent from the city’s Southeast Water Reclamation Plant (SeWRP). The effluent is stored on the Lubbock Land Application Site (LLAS), where the water has been used for irrigation of agriculture on the property for several decades. As a result, groundwater level below LLAS rose to the land surface in some places and the nitrate concentrations exceed drinking water standards over several sections. For remedial purposes, groundwater extraction wells pump a total of about 1800 gpm for discharge into the headwaters of the JBLS Lake 1. The pumped water mixes with naturally discharging groundwater and occasional stormwater as the flow follows the JBLS. Since its construction as a waterfront recreational facility, several studies have been conducted on the JBLS to define how the effluent affects the sanitary quality of the lakes, including the livelihood of fish, plankton, algae, and other microbial organisms. No basic hydrogeochemical study has been performed to determine how the waters of varying origins (LLAS groundwater, surface runoff, and natural groundwater) contribute to the lake’s water budget and how chemical and biological processes influence the composition of the lake water. The purpose of this study is, by combining historic data available from the city of Lubbock and new hydrogeochemical data being acquired along the lake system, to identify how the different waters contribute and interact with seasonal chemical and biological reactions that change the water quality from the headwaters at Lake 1 to the dam of Lake 6. These processes in turn directly affect how microbial organisms thrive in these lake waters. In semiarid regions such as West Texas, the availability and quality of water resources are becoming increasingly an urgent issue. Better understanding of water budget and biochemical processes in the JBLS obtained from this study are expected to contribute to the current and future planning of water resource management in Lubbock and surrounding regions.