Warm Springs Indian Reservation, Oregon
Client: The Confederated Tribes of the Warm Springs Indian Reservation of Oregon, Warm Springs Power Enterprises
Project: Warm Springs Indian Reservation, Oregon
Water Rights Settlement Agreement
After many years of negotiation, the Confederated Tribes of the Warm Springs Indian Reservation of Oregon (CTWS) entered into a settlement agreement with the State of Oregon and the United States Government. NRCE played a major role in negotiating a settlement with the Tribe, state of Oregon, and non-Indian users. The settlement guaranteed the Tribes a reliable and valuable source of water for satisfying their agricultural and non-agricultural needs.
NRCE provided technical and negotiation support, including extensive investigations and analysis to support the position of the Tribes in establishing the instream flow, power generation, and consumptive-use water rights contained in the agreement. The technical support included investigation, analysis, and summary of:
- Climatic conditions and precipitation patterns
- Surface water and groundwater resources and modeling
- Instream flow modeling and flow requirements
- History and characteristics of irrigation
- Arability of the lands, including delineation and mapping of irrigated and irrigable lands
- Present and future agricultural, domestic, commercial, municipal, and industrial water uses
- Conceptual water resources development plan
Pelton-Round Butte Project FERC Relicensing
NRCE was hired by Warm Springs Power Enterprises to provide technical assistance in the Federal Energy Regulatory Commission (FERC) Relicensing Proceedings for the Pelton-Round Butte Project, Deschutes River, Oregon. The Project is jointly licensed to Portland General Electric (PGE) and the CTWS. Both PGE and CTWS have applied for a license to operate the entire project. NRCE performed hydrologic analyses of the Deschutes River Basin that were incorporated in the Tribes’ Final License Application. NRCE has also assisted the Tribes in the development of the proposed minimum flows for the project.
Deschutes River Water Quality
NRCE evaluated the water quality impacts of ecosystem level mitigation measures for the Deschutes River Basin related to the Pelton-Round Butte Project. A comprehensive hydrological model of the Deschutes Basin was used to assess the impact of water conservation activities on streamflows and groundwater discharge under variable conservation scenarios. The results of the hydrologic model were coupled with a water temperature sensitivity model to determine the relative effectiveness of mitigation strategies in achieving water temperature objectives. The project included a literature review of a broad spectrum of ecosystem mitigation measures including stream stabilization, agricultural water conservation, and habitat improvement. The purpose of the literature review was to identify the relative effectiveness of potential mitigation measures to achieve water quality improvements. More detailed analyses of constructed wetlands to reduce nutrient loadings were completed in response to phytoplankton concerns in the Pelton-Round Butte system.
Deschutes River Hydrologic Modeling
NRCE developed a hydrologic model of the Deschutes River Basin in Oregon using the MODSIM modeling software. The model simulates the operation of major Deschutes and Crooked River basin reservoirs. The model also represents all major water uses in the basin, including agricultural, municipal, and industrial uses from both surface and groundwater sources. The model represents surface water/groundwater interactions with an intricate network of response functions. The model is being used in a water management planning effort to analyze the impacts of groundwater withdrawals on streamflows in the Basin as well as to analyze a number of proposed mitigation scenarios, such as canal lining. The model can also be used to enhance reservoir operations in the basin.
NRCE also developed a tool used to forecast streamflows at the Pelton-Round Butte Hydropower Project. This streamflow forecasting tool uses principal component analysis (PCA) to develop a statistical relationship between data such as snowpack, precipitation, antecedent streamflow, and climatic indicators including the El Niño Southern Oscillation (ENSO) and future streamflows for periods as far as nine months in advance. These forecasts can be used to maximize hydropower generation through enhanced reservoir operations. Predictions of streamflow are also used to predict hydropower generation, which can be used for planning and budgeting purposes.