Sprague River Oregon Geomorphology, with assessment of return flow potential

The Klamath Basin Restoration Agreement (KBRA) was developed by a diverse group of stakeholders, Federal and State resource management agencies, Tribal representatives, and interest groups to provide a comprehensive solution to ecological and water-supply issues in the Klamath Basin. The Off-Project Water Program (OPWP), one component of the KBRA, has as one of its purposes to permanently provide an additional 30,000 acre-feet of water per year on an average annual basis to Upper Klamath Lake through “voluntary retirement of water rights or water uses or other means as agreed to by the Klamath Tribes, to improve fisheries habitat and also provide for stability of irrigation water deliveries.” The geographic area where the water rights could be retired encompasses approximately 1,900 square miles. The OPWP area is defined as including the Sprague River drainage, the Sycan River drainage downstream of Sycan Marsh, the Wood River drainage, and the Williamson River drainage from Kirk Reef at the southern end of Klamath Marsh downstream to the confluence with the Sprague River. Extensive, broad, flat, poorly drained uplands, valleys, and wetlands characterize much of the study area. Irrigation is almost entirely used for pasture.
To assist parties involved with decisionmaking and implementation of the OPWP, the U.S. Geological Survey (USGS), in cooperation with the Klamath Tribes and other stakeholders, created five hydrological information products. These products include GIS digital maps and datasets containing spatial information on evapotranspiration, subirrigation indicators, water rights, subbasin streamflow statistics, and return-flow indicators.

克拉马斯盆地恢复协议（Klamath Basin Restoration Agreement, KBRA）由多元利益相关方、联邦与州级资源管理机构、部落代表及利益团体共同制定，旨在为克拉马斯盆地的生态与供水问题提供综合性解决方案。项目外水权计划（Off-Project Water Program, OPWP）作为该协议的组成部分之一，其核心目标之一是通过"克拉马斯部落认可的自愿水权赎回、用水权益让渡或其他约定方式"，年均永久向上克拉马斯湖额外供应3万英亩-英尺的水量，以改善渔业栖息地，并保障灌溉输水的稳定性。可开展水权赎回的地理范围总面积约为1900平方英里。项目外水权计划覆盖区域包括：斯普拉格河流域、锡坎沼泽下游的锡坎河流域、伍德河流域，以及从克拉马斯沼泽南端的柯克礁至与斯普拉格河汇流处的威廉姆森河流域。研究区域的大部分区域为广袤平坦、排水不良的高地、河谷与湿地。区内灌溉几乎全部用于牧草种植。
为协助参与项目外水权计划决策与实施的各方开展工作，美国地质调查局（U.S. Geological Survey, USGS）联合克拉马斯部落及其他利益相关方，开发了五类水文信息产品。这些产品包括地理信息系统（Geographic Information System, GIS）数字地图与数据集，涵盖蒸散发、地下灌溉指标、水权、子流域径流统计数据以及退水指标的空间信息。