Evaluating the Impacts of Potential Wastewater Reuse on Streams in the Red River Basin of Oklahoma

Increasing water usage and demands, combined with potentially less source water  as a result of climate change impacts, are causing water resource managers to evaluate and implement alternative solutions for reducing water shortages, maximizing water availability, and reducing costs. The capture and reuse of wastewater is a promising strategy for increasing available water, but the costs and benefits of wastewater reuse are poorly quantified. In many locations, wastewater forms a significant component of stream flows for downstream beneficial uses. While wastewater reuse can boost local water availability, it also may reduce downstream flows and have negative impacts on downstream ecosystems. Therefore, assessing the changes to wastewater discharges as it relates to in-stream flows and downstream beneficial uses is critical before statewide implementation of water reuse.  

In 2018, the Oklahoma Water Survey completed a grant-funded project to improve accessibility of hard-to-find datasets related to current and historical wastewater discharges. As a result, initial tools were developed to easily retrieve and compile wastewater discharge data and evaluate outflows as a percentage of streamflow at stream gages and during precipitation events. This project will build on the previous work to analyze water balance components and water quality within the Red River basin of Oklahoma. Data such as percent total streamflow as wastewater discharge with and without water reuse will be analyzed to understand cumulative effects on in-stream flows, water quality, and other ecosystem effects (i.e. habitat).  

The over-arching objective of this project is to identify locations where wastewater reuse may offer high societal benefits with few negative impacts to downstream ecosystems. Outcomes of this project include evaluation of sub-basins within the Red River basin for prioritization of wastewater reuse implementation and potential ecological outcomes based on wastewater reuse scenarios due to changes in water quality and in-stream flows.