A baseline study of sediment and nitrogen flux in a pre-urbanized watershed, Parker County, Texas

This study investigated the dynamics of sediment and nitrogen flux in response to storm runoff in a pre-urbanized watershed in Parker County, Texas. Mary's Creek was found to be a flashy creek with unusually low runoff coefficients, suggesting a larger-than-average storage capacity of the watershed. The predominant runoff-producing mechanism was found to be a combination of Hortonian overland flow and saturation overland flow. TSS concentrations increased in response to increased discharge. However, the sediment load being transported out of this basin was found to be well below tolerable limits. NH3-N levels tended to decrease as discharge increased; whereas, NO3-N levels increased as discharge increased. Both NH3-N and NO3-N concentration levels rarely exceeded TCEQ's screening level guidelines and were determined to be of no concern. The data collected in this study can be utilized to understand the long-term effects of urbanization on the water quality of the watershed.