Groundwater flux estimation in streams: A thermal equilibrium approach

JOURNAL OF HYDROLOGY

卷:561

Article

Zhou, Yan¹  Fox, Garey A.²  Miller, Ron B.¹  Mollenhauer, Robert³  Brewer, Shannon³ 

[1] Oklahoma State Univ, Dept Biosyst & Agr Engn, Stillwater, OK 74078 USA

[2] North Carolina State Univ, Dept Biol & Agr Engn, Campus Box 7625, Raleigh, NC 27695 USA

[3] US Geol Survey, Oklahoma Cooperat Fish & Wildlife Res Unit, Stillwater, OK USA

关键词: Groundwater flux;    Thermal equilibrium;    Seepage run;    Stream water temperature;    Temperature signature;   

DOI  :  10.1016/j.jhydrol.2018.04.001

来源: Elsevier

【 摘 要 】

Stream and groundwater interactions play an essential role in regulating flow, temperature, and water quality for stream ecosystems. Temperature gradients have been used to quantify vertical water movement in the streambed since the 1960s, but advancements in thermal methods are still possible. Seepage runs are a method commonly used to quantify exchange rates through a series of streamflow measurements but can be labor and time intensive. The objective of this study was to develop and evaluate a thermal equilibrium method as a technique for quantifying groundwater flux using monitored stream water temperature at a single point and readily available hydrological and atmospheric data. Our primary assumption was that stream water temperature at the monitored point was at thermal equilibrium with the combination of all heat transfer processes, including mixing with groundwater. By expanding the monitored stream point into a hypothetical, horizontal one-dimensional thermal modeling domain, we were able to simulate the thermal equilibrium achieved with known atmospheric variables at the point and quantify unknown groundwater flux by calibrating the model to the resulting temperature signature. Stream water temperatures were monitored at single points at nine streams in the Ozark Highland ecoregion and five reaches of the Kiamichi River to estimate groundwater fluxes using the thermal equilibrium method. When validated by comparison with seepage runs performed at the same time and reach, estimates from the two methods agreed with each other with an R-2 of 0.94, a root mean squared error (RMSE) of 0.08 (m/d) and a Nash-Sutcliffe efficiency (NSE) of 0.93. In conclusion, the thermal equilibrium method was a suitable technique for quantifying groundwater flux with minimal cost and simple field installation given that suitable atmospheric and hydrological data were readily available.

【 授权许可】

Free