SEDIMENT ACCUMULATION IN BROWNSVILLE RESACAS (OXBOW LAKES)

The city of Brownsville, Texas (South Texas) relies heavily on the network of resacas or oxbow lakes that are found throughout the city for freshwater storage. Resacas, such as Resaca de la Guerra, transport and store Brownsville's drinking and irrigation water and serve as storage reservoirs during dry conditions or when the flow of the Rio Grande is low. Brownsville resacas also benefit the city due to the interconnecting culverts, weirs, and storm drain pipes that aid in flood control during heavy rains and hurricanes. Resacas also add character and serve as landmarks for the city.

Unfortunately, the one problem associated with resacas is sediment accumulation. Over time resacas fill with sediment and thus can no longer be used for the purposes mentioned beforehand. Therefore, student researchers from the University of Texas at Brownsville collected sediment data from Resaca de la Guerra. These data quantify the amount of sediment accumulated on the bottom of this resaca. These data were plotted in ArcGIS to geographically represent the depth to the unconsolidated sediment layer and depth to the consolidated clay layer measurements. Future work will include formulating a plan for possibly dredging the resacas to increase the storage capability of the system.