From introduction: The present study is an inventory and appraisal of the water resources of the reservation, including determination of flow in major streams, yield of water to wells and springs, and quality of water. This study was conducted in cooperation with the Confederated Tribes of the Warm Springs Reservation. The cooperation and assistance of many officials of the Confederated Tribes, of the Bureau of Indian Affairs, and of the Indian Health Service helped greatly. Well-drilling and test-pumping data and other information generously furnished by Satish Puri, Tribal Engineer, were especially helpful.