Sprague River Oregon Geomorphology, with assessment of subirrigation 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.克拉马斯流域恢复协议（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，旨在为克拉马斯流域的生态与供水问题提供全面解决方案。作为KBRA的组成部分之一，项目外水计划（Off-Project Water Program, OPWP）的核心目标之一，是通过"自愿退役水权或用水行为，或经克拉马斯部落同意的其他方式"，年均永久向上克拉马斯湖额外提供3万英亩英尺的水量，以改善渔业栖息地，同时保障灌溉供水的稳定性。可退役水权覆盖的地理范围约为1900平方英里。OPWP的覆盖区域包括斯普拉格河（Sprague River）流域、赛坎沼泽下游的赛坎河（Sycan River）流域、伍德河（Wood River）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（Williamson River）流域。该研究区域的大片区域以广袤平坦、排水不良的高地、谷地与湿地为主要特征，区内灌溉几乎全部用于牧场生产。