WATER QUALITY IN THE NORTH BOSQUE RIVER WATERSHED, ERATH COUNTY TEXAS

The North Bosque River watershed in Erath County, Texas is characterized by high spatial density dairy farms. Water samples were collected from the Bosque River, select tributaries, and Lake Waco to evaluate water quality in relation to proximity to dairy farming. Most of the dairy farms are located in the upper watershed within the study area. Preliminary results show that pH ranged from 6.5 to 8.6 and the oxidation reduction potential (ORP) ranged from -4 to 155 mV. The highest pH and lowest OPR values were observed in the stream segments in the upper watershed. Dissolved oxygen ranged from 2 to 18 mg/L with lower values in the upper watershed. The specific conductance ranged from 1600 micro Siemens/cm decreasing downstream to about 500 micro Siemens/cm in Lake Waco. Alkalinity values ranged from 152 to 358 mg/L with the lowest values at Lake Waco. Major cations analysis show that calcium ranged between 51 to 128 mg/L, magnesium between 2 to 65 mg/L, potassium between 1 to 13 mg/L, and sodium between 8 to 111 mg/L. The specific conductance, potassium, magnesium and sodium showed much higher values within the upper watershed and lower values in the lower watershed. Our results indicate that poor water quality was observed mainly in the upper watershed where the most dairy farms are located. We conclude that the diary operations in the upper watershed of the North Bosque River may be impacting surface water quality.