Lone Star Healthy Streams: Two Years of Examining Alternative Water Sources as a Best Management Practic.

According to the DRAFT 2008 Water Quality Inventory and 303(d) List, 386 water bodies are impaired in Texas. Of these, approximately half of the impairments are due to excessive bacteria. Bacterial source tracking in a number of water bodies has identified a contribution from cattle to bacteria loading of these streams. Grazing lands, which represent the dominant land use in the majority of watersheds in Texas, have received little attention until recently regarding the effect of grazing livestock on water quality. A perennial stream segment was selected to evaluate whether or not an alternative water source could reduce the time grazing livestock spend in or near the riparian area. Water to existing water troughs was terminated for 12 months to force the cattle to obtain water from the stream segment. Water samples from the stream segment were obtained twice monthly for the 12-month period. One sample was obtained where the creek entered the cooperating landowner’s property and a second sample was obtained just as it left the landowner’s property. Water was analyzed for E. coli and expressed as colony forming units per 100 ml of water. After 12 months the water was made available to the water troughs again and the twice-monthly sampling protocol was continued for an additional 12 months. Every three months, eight randomly selected beef cows from the resident cow herd were fitted with GPS collars (Fig. 2) four times each year. The collars remained on the cows for approximately 21 days. Data points regarding the location of each cow was collected each five minutes. The data was analyzed to determine how much time the cows spent within close proximity to the stream with or without access to an alternative water source. Thus far, the data collected indicates that in the presence of an alternative water source, cattle spent 57% less time within 15 m of the stream. Levels of E. coli bacteria, based on fecal coliform counts were higher, on average, leaving the property compared to the level entering the property. The presence of an alternative water source, however, did not reduce the bacteria levels compared to levels when cattle were forced to water in the stream. One explanation for this finding could be the failure of the landowner to reduce stocking rate during an extreme drought, thus reducing the quantity of forage in the riparian area that could have served as an effective filter strip. While the data demonstrates a marked reduction in time spent in the riparian area by cattle when provided with an alternative water source, our data is not conclusive regarding the effectiveness of alternative water sources in reducing bacteria loading in stream segments. More information examining the effects of alternative water sources on cattle behavior is required.