Incorporating Ecological Costs and Benefits into Environmental Flow Recommendations For Oklahoma Rivers: Phase 1, Southeastern Oklahoma

Abstract

Providing a safe and sustainable water supply to the growing Oklahoma population while also providing for economic growth and maintaining natural ecosystems is the most serious challenge facing Oklahoma policy makers in the coming decades. Accomplishing this will require consideration of both the economic and ecological costs and benefits of different water allocation and management strategies (Arthington et al. 2006, Richter 2010). Multiple approaches have been used to attempt to quantify the amount of water needed by natural water bodies in Oklahoma. In-stream flows (ISFs) quantify the amount of water that needs to be left in a stream to maintain non-consumptive uses such as fisheries or riparian areas (OWRB 2009). Currently, there are over 200 methods for determining ISFs, ranging from designation of minimum flows to those that mimic natural flow regimes (Turton et al. 2009).

Rivers in the Ouachita and Gulf Coastal Plains ecoregions of southeastern Oklahoma provide an excellent test system for examining the ecological costs and benefits of different environmental flows/in-stream flow recommendations. These rivers are known for their relatively abundant and pristine water and harbor the highest aquatic biological diversity in the state (Matthews et al. 2005). However, the water in these rivers also is in high demand to meet regional, human water needs (http://www.owrb.ok.gov/supply/ocwp/ocwp.php). In particular, the Kiamichi River is at the center of intense conflict over water use and governance between Oklahoma City, the State of Oklahoma, the Tarrant County Water District (Fort Worth, TX), and the Choctaw and Chickasaw nations. The source of conflict is over who gets to use water from a storage reservoir. Sardis Lake is an impoundment on a tributary to the Kiamichi. The Corps of Engineers built this reservoir in 1982 for flood control, water supply and recreation. However, Oklahoma owed money to the federal government for constructing the reservoir, and in 2011 90% of the water storage rights to Sardis Lake were sold to Oklahoma City. The Tarrant County Water District disputes this ownership. Under the 1978 Red River Compact (http://www.oscn.net/applications/oscn/deliverdocument.asp?id=97778&hits=), they claim to have rights to 25% of the water from Sardis Lake, and they want Oklahoma to sell it to them.