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Design of Optimum Selective Withdrawal Operation for Temperature Management at Round Butte Dam, Lake Billy Chinook, Oregon. Presentation to WEFTEC 2000 by Curtis DeGasperi - Foster Wheeler Tarang Khangaonkar – Foster Wheeler Steven Breithaupt – Foster Wheeler
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Design of Optimum Selective Withdrawal Operation for Temperature Management at Round Butte Dam, Lake Billy Chinook, Oregon Presentation to WEFTEC 2000 by Curtis DeGasperi - Foster Wheeler Tarang Khangaonkar – Foster Wheeler Steven Breithaupt – Foster Wheeler Kevin Marshall – Portland General Electric (PGE) October 18, 2000
Study Area – Lake Billy Chinook Columbia River Portland, Oregon Deschutes River Basin Lake Billy Chinook
Study Area – Problem Definition Cool river runoff Warm river runoff
Problem Definition • Pelton Round Butte Project – Existing Condition • Inflow from three different tributaries • Release of colder bottom water at Round Butte • Seasonal stratification in Lake Billy Chinook (LBC) • Complex flow patterns in the reservoir • Result • Ineffective fish passage at Round Butte Dam • Modification of downstream temperature regime
Objective and Modeling Approach • Primary Objective: Re-establish downstream fish passage at Round Butte Dam • Provide required downstream attraction flow • Make effective modification of reservoir flow patterns • Secondary Objective – Address project-related in-lake and downstream water quality issues • Modeling Approach - Develop the ability to simulate hydrodynamic behavior and water quality response of Lake Billy Chinook
Development of BETTER Water Quality Model • Background • Water quality limited [303(d)] listing for Lake Billy Chinook for chlorophyll a and pH • Lake productivity establishes available food sources and also affects dissolved oxygen (DO) and pH levels • Objective • Develop a predictive water quality (eutrophication) model of Lake Billy Chinook
Development of BETTER Water Quality Model Recommend preliminary calibration to existing 1995 data Calibrate model to match observed in-lake temperature, TSS, DO, pH, alkalinity, algal biomass, and nutrients Apply the calibrated model to proposed Blend 13 operational modification
Field Data Station Locations(1994-1997) and (January-July 1999)
BETTER Model Inputs • Hydrology – Tributary flow and temperature, and powerhouse withdrawal • Climatology – Air and dew point temperature, wind speed, solar radiation • Water Quality – DO, pH, alkalinity, nutrients, organic matter, algae
Temperature Verification – Forebay Temperature Profiles - 1999
Model Alternative Studies Detail Specifications of Alternatives 1-4
Development of Selective Withdrawal Alternative • Design Criteria - Compliance with temperature standards • Release of cold surface waters in winter and spring • Deeper colder water stored for release in summer • Release of surface water with deeper colder water as needed • Hydrodynamic model results indicated that surface withdrawal provides currents beneficial to fish collection
Surface/Bottom Water BlendingBlend 2: regression to Rereg temperature Percentage of Surface Water Withdrawn
Surface/Bottom Water BlendingBlend 4: regression to Rereg temperature Percentage of Surface Water Withdrawn
Surface/Bottom Water BlendingBlend 13: regression to Rereg temperature Percentage of Surface Water Withdrawn
Blend13 vs. Existing Condition - LBC 1995 temperature Existing Blend 13 Deschutes Branch Existing Metolius Branch Crooked Branch
Summary and Conclusions • Temperature calibration/verification complete • Preliminary water quality calibration complete • Model Application to Blend 13 Selective Withdrawal run • Increase in in-lake and discharged DO • Improves in-lake and downstream temperatures • Small increase in pH • Proposed model improvements • Sampling to define tributary BOD and detritus loads