||The Sevier River Basin is unique as it is Utah's largest river basin and its entire drainage area is contained within the state. The Sevier River is one of the most utilized rivers in the nation. Only four percent or an average of about 32,900 acre-feet of the total tributary inflow reaches its terminus, Sevier Lake, and then only on an intermittent basis. To achieve this level of use, water is diverted upstream, used, and then it reappears as return flow and is rediverted downstream and used again. Water users repeat this process along the entire length of the Sevier River. The groundwater reservoirs are used for storage with recharge and discharge continually occurring, thus maintaining the downstream river flows.