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ARS Home » Southeast Area » Stoneville, Mississippi » Pollinator Health in Southern Crop Ecosystems Research » Research » Publications at this Location » Publication #387151
Research Project: Ecological Assessment and Mitigation Strategies to Reduce the Risks of Bees to Stressors in Southern Crop Ecosystems

Location: Pollinator Health in Southern Crop Ecosystems Research

Title: Low flow trends in Texas stream segments serving unique hydrologic functions

Author
item VENKATARAMAN, KARTIK - Tarleton State University
item Kannan, Narayanan
item CHRAIBI, VICTORIA - Tarleton State University

Submitted to: Texas Water Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/12/2022
Publication Date: 2/20/2023
Citation: Venkataraman, K., Kannan, N., Chraibi, V. 2023. Low flow trends in Texas stream segments serving unique hydrologic functions. Texas Water Journal. 14(1):3-33. https://doi.org/10.21423/twj.v14i1.7143.
DOI: https://doi.org/10.21423/twj.v14i1.7143

Interpretive Summary: Some sections of the rivers in Texas were classified as environmentally very important because their widespread usefullness to human and many other living organisms. In this study we evaluated trends in water flow of these important sections of the river using daily data from 1970 to 2019 and advanced statistical methods. We have found decreasing trends during summer time flow and decreasing river flow during non-rainy periods for the South Fork of the Guadalupe River, the Sabinal River and the Frio River. Increasing evaporation because of increasing temperature is the major reason for drying rivers. Unique local landscape and surface water management also play some minor roles of the rivers drying up in summer and non-rainy periods. The findings will be useful for making future water management decisions.

Technical Abstract: In recognition of the unique hydrologic functions they serve, certain stream segments in Texas have been designated as ecologically significant. In this study, we have evaluated low-flow trends in seven hydrologically unique stream segments spanning three climate divisions in Texas from 1970 to 2019. Despite increasing mean annual temperatures, there are no trends in low-flows or other hydrologic variables in the East Fork of the San Jacinto River in the Upper Coast climate division, likely due to local moisture surplus effects from the Gulf of Mexico. In the Edwards Plateau climate division, annual lowflows and annual baseflows are decreasing in the South Fork of the Guadalupe River, the Sabinal River and the Frio River; whilst increasing mean annual temperatures has a significant role in the drying of all three stream segments, increasing annual potential evapotranspiration (PET) appears to be an additional driver in the Sabinal and Frio Rivers. Analysis of the Standardized Streamflow Index (SSI) indicates that all seven stream segments experienced their worst streamflow droughts in the 2010s. Whilst climate appears to be a significant driver of the drying observed in the Edwards Plateau climate division, local karst landscapes and surfacewater management likely play secondary roles in this phenomenon.