1. Curtis DeGasperi - Foster Wheeler Tarang Khangaonkar – Foster Wheeler
A Water Quality Model of Lake Billy Chinook: Application to Issues Associated with Anadromous Fish Passage and Bull Trout
Presentation to WALPA by
Curtis DeGasperi - Foster Wheeler
Tarang Khangaonkar – Foster Wheeler
Kevin Marshall - PGE
April 13, 2000
My presentation covers a portion of an ongoing hydrodynamic and water quality modeling effort conducted for Portland General Electric (PGE) as part of their adaptive management plan to restore anadromous fish passage above Round Butte Dam on the Deschutes River in eastern Oregon. PGE is also in the process of renewing their FERC license and obtaining a 401 Water Quality Certification from the state of Oregon. PGE’s primary goal is the restoration of anadromous fish passage. Fish passage attempts were made when the dam was first constructed in the mid 1960s…however, these attempts were unsuccessful and fish passage efforts were discontinued. A secondary goal is to attempt modifications in existing project operations to meet water quality goals within the lake and downstream.

2. Lake Billy Chinook (LBC) - Study Area -
Columbia River
Portland, Oregon
Deschutes River Basin
This figure shows the study area, the Deschutes River basin in eastern Oregon drains north to the Columbia River. The Willamette basin and Portland are just to west. The Pelton Round Butte Project and Lake Billy Chinook is located about mid-point in the basin at an elevation of 1950 feet (600 m)
Lake Billy Chinook

3. Lake Billy Chinook (LBC) - Study Area -
Cool river runoff
This figure shows the study area, the inflow tributaries, the Round Butte Dam and Lake Billy Chinook formed by the dam. The crooked and Deschutes river temperatures are always 5 deg.C warmer than Metolius River. In the summer, the lake is warmer than Metolius but is cooler than Crooked and Dechutes, and there is a strong pycnocline at approximately meter depth. The Metolius River enters the Lake and dives under the pycnocline. The Dechutes and Crooked Rivers ride on top of the hypolimnion towards the confluence. The discharge however occurs from the bottom. Therefore the warm Crooked River waters and the juveniles continue to travel upstream into Metolius instead of trying to find the outlet.
Warm river runoff

4. Problem Definition Pelton Round Butte Project – Existing Condition
Inflow from three different tributaries
Release of colder 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
Pelton Round Butte project is located on the Dechutes River. It consists of three dams the Round Butte, the Pelton, and the Rereg Dam. Round Butte Dam is located at the confluence of three tributaries that are distinct in their flow and temperature characteristics. The discharge at Round Butte occurs in a peaking mode and occurs at the bottom. Release of cold water and surface heating in the summer results in a pronounced stratification. The net result is a complex circulation pattern which results in ineffective passage of fish.

5. 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
The overall objective of this project is to design structural and operational changes at the Round Butte dam that would allow for effective fish collection. Ideally, the structural and operational changes would effectively alterr the flow patterns in the reservoir, provide required attraction flow
The specific objective of this modeling study was to develop the ability to simulate the hydro thermal response of Lake Billy Chinook. The models would allow testing of proposed alternatives to evaluate if the Lake is going to respond in a favorable manner and in a significant manner to make the expenditure worthwhile.

6. 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
The need for a water quality model of Lake Billy Chinook was felt because o f two reasons. One was that Lake Billy Chinook has been listed on the Sate of Oregon’s water quality limited list. In order to continue operations PGE needs a Section 401 water quality certificate. To obtain this certificate, PGE needed to demonstrate to ODEQ that it had the ability to achieve compliance in the future through modification of their operations. This could be accomplished with the help of a Water quality model. Secondly, the proposed operational changes would impact DO and phytoplankton levels. These have implications with respect to fisheries issues.

7. Development of BETTER Water Quality Model

8. 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

9. Field Data Station Locations (1994-1997) and (January-July 1999)
In 1999 PGE maintained continuous temperature monitoring stations near the tributary inflow locations and the forebay. They also maintained monthly temperature profiling locations, one in each arm and the forebay. In addition PGE collected bi-weekly profiles at 4 more locations. This was suplemented by the ENSR synoptic monitoring stations at 4 locations. Together this provided a comprehensive coverage of the entire study area.
PGE collected wind data at three stations (forebay, Metolius, and Dechutes)
ENSR conducted continuous current profile monitoring from April through July at four locations. ENSR also monitored temperature profiles at the same locations.

10. BETTER Model Segmentation

11. BETTER Model Geometry Deschutes branch geometry

12. 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

13. Tributary Inflows and Rainfall 1995

14. Meteorological Inputs - 1995

15. Water Quality Inputs Temperature 1995

16. Water Quality Inputs Nutrients and Algal Biomass 1995

17. In-Lake Water Quality Algal Biomass and Succession 1995

18. BETTER Model Calibration Data
Temperature
Dissolved Oxygen (DO) pH
Algal Biomass
Turbidity
Transparency
Alkalinity
Nutrients

19. Temperature Calibration Forebay Temperature Profiles - 1995

20. DO Calibration July 1995

21. pH Calibration July 1995

22. Algae and Nutrients Calibration
Ammonium-N
Nitrate-N
Ortho-P
Chlorophyll a

23. Temperature Verification – Forebay Temperature Profiles - 1999

24. Model Alternative Studies Detail Specifications of Alternatives 1-4

25. 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

26. Temperature Correlation RBD and Rereg

27. Surface/Bottom Water Blending Blend 2: regression to Rereg temperature
Percentage of Surface Water Withdrawn

28. Surface/Bottom Water Blending Blend 4: regression to Rereg temperature
Percentage of Surface Water Withdrawn

29. Percentage of Surface Water Withdrawn
Surface/Bottom Water Blending Blend 13: regression to Rereg temperature
Percentage of Surface Water Withdrawn

30. Blend13 vs. Existing Condition - LBC 1995 temperature
Deschutes Branch
Existing
Metolius Branch
Crooked Branch

31. Blend 13 vs. Existing Condition LBC Dissolved Oxygen
Existing Condition – Forebay Time Series
Blend 13 – Forebay Time Series

32. Blend 13 vs. Existing Condition LBC pH
Existing Condition – Forebay Time Series
Blend 13 – Forebay Time Series

33. 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