Characterization of Lower Rio Grande Valley Watershed

Abdulkabir Aduragba, The University of Texas Rio Grande Valley

Copyright 2023 Abdulkabir Aduragba. All Rights Reserved.

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Abstract

The Lower Laguna Madre (LLM) is an estuary wetland along the Gulf of Mexico that receives freshwater from the Lower Rio Grande Valley (LRGV) watersheds. The freshwater flows from the LRGV watersheds into the estuary through five different waterways, namely: Raymondville Drain (RVD), Hidalgo/Willacy Main Drain (HWMD), International Boundary & Water Commission North Floodway (IBWCNF), Arroyo Colorado drain, and Brownsville Ship Channel (BSC). The estuary is considered impaired because of the high concentration of bacteria and low level of dissolved oxygen (DO). Since the estuary receives its freshwater from the Lower Rio Grande Valley (LRGV) watersheds, the watershed characterization became necessary to understand the causes of the impairment. So far, the watersheds are being studied by relying on water quality data of the contributing drainages and high-level State resource geographic data to identify watershed boundary, and pollutant sources. It was observed that the major cause of impairment in LLM estuary is the excess use of agricultural input, followed by the influence of urbanized area, and the industrial waste management in the LRGV watersheds.