Understanding the Effects of Groundwater Pumping on Streamflow: Human-Feedback Analysis on Downstream Impacts and Relevance to Reservoir Management

Abstract:

To reduce the vulnerability of the surface water supply system from extreme drought, groundwater withdrawal has always been considered as an additional source for water supply. Since surface water process and groundwater are inter-connected, groundwater withdrawal reduces the amount of streamflow resulting in depletion downstream. Hence, a conjunctive management of surface water and groundwater resources is important to support the sustainable use of water resources. We propose a modeling framework that captures the conjunctive management on surface and groundwater resources for promoting freshwater sustainability.

A fully coupled hydrologic model, Penn State Integrated Hydrologic Model (PIHM), has been applied to assess the effects of groundwater pumping on streamflow. The impact of groundwater pumping on streamflow during historic drought events has been evaluated to quantify the resiliency and vulnerability of the target watershed, the Haw (located in NC) and Verde River basin (located in AZ). Further, the groundwater pumping model is combined with a reservoir, Lake Jordan, model for developing optimal pumping strategies during droughts. The proposed conjunctive management model could also be used for assessing instream water quality due to pumping in local watersheds