Detroit_90_percent_EDR_Agency_Review.pdf

North Santiam River

Detroit Dam on the North Santiam River

90% Engineering Documentation Report

February 2017

Detroit and Big Cliff Long-Term Temperature Control and Downstream Fish Passage

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EXECUTIVE SUMMARY

This Engineering Documentation Report (EDR), or alternatives study, was developed per Reasonable and Prudent Alternative (RPA) measures 4.12.3 and 5.2 in the 2008 Willamette Biological Opinion (BiOp).

The EDR addresses the feasibility of and project-specific alternatives to meet downstream water temperature criteria through optimizing operations, upgrading current structures, and/or installing a temperature control facility at Big Cliff or Detroit Dams. The goal of meeting downstream water temperature criteria contains a provision for inclusion of downstream fish passage, if found feasible and compatible.

Operational temperature control is hampered by the current project configuration. This is due to the structural limitations at Detroit Dam (i.e., limitation in available outlets) to pass water at multiple elevations (above and below the thermocline) to meet downstream temperature targets. During early spring, water temperatures released from Detroit Dam are typically cooler than the downstream temperature targets while during the autumn/early winter, water temperatures are typically warmer than the downstream targets.

Interim temperature control operations have improved downstream temperatures and should continue until a permanent solution is in place. The interim operations fall short in the spring – warm water (from the upper part of the reservoir water column) is unavailable for release until the reservoir is above the spillway crest. This results in a release of cooler than desired water early in the year. Once the reservoir fills above the spillway crest, warm, surface water becomes accessible with the spillway gates. With existing equipment and optimized operations, temperature control is achievable during the summer months until the reservoir is drafted below the spillway crest (per minimum outflow and/or following the rule curve). Once the reservoir is below spillway crest, the penstocks are used to discharge water downstream. This can result in cooler than desired downstream water temperatures, leaving warm surface water in the reservoir inaccessible. As the pool continues to draft into autumn and early winter, the warm surface water approaches the penstock, resulting in releases of warmer than desired water in autumn/winter and until the lake has turned over (i.e., become isothermal). This pattern is noticeable in cool/wet and normal temperature years and is very pronounced in hot/dry temperature years. In addition, all interim temperature operations are sensitive to equipment outages, scheduled and/or unscheduled.

Temperature modeling indicates that downstream water temperature targets cannot be met in autumn and early winter with the existing equipment without modifying the rule curve to stay above spillway crest approximately 45 later days in the year, extending the period when warm water is accessible. Keeping the pool higher for that length of time would require reductions in the amount of water provided during the Upper Willamette River (UWR) Chinook spawning period and would increase in the amount of water discharged from Detroit Dam when redds are present downstream. In addition, delaying drawdown of the reservoir would impact the Corps of Engineers’ flood risk management mission.

A structural solution will be required to meet downstream temperature targets throughout the year.

Temperature modeling has identified multiple structural alternatives concepts that have the capability to meet downstream temperature targets. The recommended structural temperature control solution assumed to be the most compatible with fish passage requirements, based on the current biological data and assumptions, is a selective withdrawal structure (SWS) with a floating outlet and a fixed lower outlet.

This assumption does not preclude operational passage options if they are determined to be effective.

Existing water temperature modeling has provided the elevation and flow rates required for the outlets.

Modeling has been primarily focused on meeting downstream temperature targets; further modifications

90% EDR - February 2017 ES-2 and refinements will be made to accommodate requirements for downstream fish passage and other project operational and structural limitations. Temperature modeling indicates that the elevation of the lower fixed outlet must be below the penstock elevation; positioning the fixed outlet at elevation 1340 feet (upper regulating outlet elevation) achieves downstream temperature control targets.

Collaborative discussions with NOAA to develop performance standards for Detroit will continue. The PDT’s overarching biological working assumption is to maximize survival for downstream passage of juvenile and adult chinook and steelhead at Detroit Dam.

The PDT has been working closely with the Cougar PDT as they evaluate fish passage alternatives.

Lessons learned from Cougar will be applied at Detroit. On 19 October 2016, the Cougar PDT and other USACE employees conducted a downstream passage workshop to identify fish behavior, design considerations, constraints, and risks. Following the workshop, some key considerations identified for Detroit include:

1. Utilize fish behavior in design features using data from Detroit studies and other passage structures in the region.

2. Maximize the hydraulic signature in the forebay in front of the entrance to optimize fish attraction.

3. Position entrance as close to the dam as possible and consider perpendicular orientation to utilize the dam as a guidance feature.

4. Shape the entrance to minimize rejection and hydraulic drop to achieve capture velocities.

5. Minimize competing flow to reduce the potential for false attraction.

6. Exclude fish from areas that would limit their ability to find the entrance such as on the north side of the temperature control tower and between the tower and dam. Create an artificial shoreline.

7. Prevent the ability of predators to get under the structure.

8. Operate structure during critical periods for passage such as the transition from day to night and overnight to the extent possible.

9. Identify the appropriate engineering tools to evaluate design such as CFD and/or physical modeling.

10. Debris management plans and design are critical for O&M to maintain operation and maximizing condition and survival.

11. Minimize handling to the extent possible.

For the 90% EDR, downstream fish passage solutions were prioritized and ranked. Also, details of the recommended plan for both temperature control and downstream passage are introduced. The recommended alternatives to carry forward to design are both the selective withdrawal structure with a weir box (phase 1) and the selective withdrawal structure (phase 2) with a floating screen structure. The selective withdrawal structure with a weir box is the highest ranking alternative and has a lower cost than the floating screen structure. However, the weir box concept is untested for large scale fish passage.

Therefore, the recommendation is to proceed with the design of the selective withdrawal structure with a weir box and also start the DDR for the floating screen structure for downstream fish passage. The recommendation is to construct the selective withdrawal structure and the weir box concurrently. After construction is complete, the weir box would be tested to determine biological effectiveness. The recommended schedule for design and construction of the Detroit temperature control and downstream fish passage alternatives is as follows:

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- Selective Withdrawal Structure:

o DDR: Oct 2016 – Sept 2018 o P&S: Oct 2018 – Apr 2020 o Construction: Oct 2020 – Jun 2023

- Weir Box:

o DDR: Apr 2017 – Sept 2018 o P&S: Oct 2018 – Apr 2020 o Construction: Oct 2020 – Jun 2023 o Testing: Jun 2023 – Jun 2024

- Floating Screen Structure:

o DDR in support of Phase 1: Apr 2017 – Sept 2018 o DDR in support of Phase 2: Jun 2021 – Dec 2022 o P&S: Jan 2022 – Jun 2024 o Construction: Nov 2024 – Aug 2027

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TABLE OF CONTENTS

EXECUTIVE SUMMARY

ACRONYMS AND ABBREVIATIONS

1. INTRODUCTION ............................................................................................................................. 1-1

1.1. PURPOSE AND SCOPE .................................................................................................................. 1-1

1.2. PROJECT AUTHORIZATION ......................................................................................................... 1-1

1.3. PROJECT LOCATION ................................................................................................................... 1-2

2. DESCRIPTION OF CURRENT PROJECT FEATURES ................................................................. 2-1

2.1. PERTINENT DATA ....................................................................................................................... 2-1

2.2. OPERATIONAL RESTRICTIONS .................................................................................................... 2-4

2.3. HYDROLOGY AND RESERVOIR REGULATION ............................................................................. 2-7

3. EXISTING CONDITIONS ................................................................................................................ 3-1

3.1. WATER TEMPERATURE .............................................................................................................. 3-1

3.2. TOTAL DISSOLVED GAS ............................................................................................................. 3-5

3.3. FISH PASSAGE CONDITIONS ....................................................................................................... 3-6

4. CRITERIA AND CONSIDERATIONS ............................................................................................ 4-1

4.1. WATER TEMPERATURE EVALUATION CRITERIA AND OPERATIONAL TARGETS ........................ 4-1

4.2. BIOLOGICAL CRITERIA AND CONSIDERATIONS ......................................................................... 4-2

4.3. DOWNSTREAM PASSAGE CRITERIA AND CONSIDERATIONS ...................................................... 4-6

4.4. OPERATIONS AND MAINTENANCE CRITERIA AND CONSIDERATIONS ........................................ 4-7

4.5. DAM SAFETY CRITERIA AND CONSIDERATIONS ...................................................................... 4-20

4.6. HYDRAULICS ............................................................................................................................ 4-21

4.7. HYDRAULIC CRITERIA AND CONSIDERATIONS ........................................................................ 4-24

4.8. STRUCTURAL CRITERIA AND CONSIDERATIONS ...................................................................... 4-32

4.9. GEOTECHNICAL CRITERIA AND CONSIDERATIONS ............................................................. 4-44

4.10. MECHANICAL CRITERIA AND CONSIDERATIONS ................................................................. 4-49

4.11. ELECTRICAL CRITERIA AND CONSIDERATIONS ................................................................... 4-52

5. WATER TEMPERATURE CONTROL ALTERNATIVES ............................................................ 5-1

5.1. WATER TEMPERATURE CONTROL ALTERNATIVES ..................................................................... 5-1

6. EVALUATION OF WATER TEMPERATURE CONTROL ALTERNATIVES ............................ 6-1

6.1. WATER TEMPERATURE MODELING ............................................................................................ 6-1

6.2. COMPUTATIONAL FLUID DYNAMICS MODEL ............................................................................ 6-5

6.3. WATER TEMPERATURE CONTROL ALTERNATIVES EVALUATION MATRIX ........ 6-13

6.4. ALTERNATIVES EVALUATION MATRIX DISCUSSION ................................................ 6-13

7. DOWNSTREAM FISH PASSAGE ALTERNATIVES .................................................................... 7-1

7.1. DOWNSTREAM PASSAGE ALTERNATIVES ................................................................................. 7-1

7.2. DOWNSTREAM FISH CONVEYANCE ALTERNATIVES ................................................................ 7-18

8. EVALUATION OF DOWNSTREAM FISH PASSAGE ALTERNATIVES ................................... 8-1

8.1. FISH BENEFITS WORKBOOK ...................................................................................................... 8-1

8.2. HEC-RESSIM MODEL ................................................................................................................ 8-6

8.3. ALTERNATIVES EVALUATION MATRIX ...................................................................................... 8-7

8.4. ALTERNATIVES EVALUATION MATRIX DISCUSSION ................................................................. 8-7

9. SELECTED PLAN ............................................................................................................................ 9-1

9.1. DESCRIPTION OF PLAN FEATURES ............................................................................................. 9-1

10. CONSTRUCTION AND COST ESTIMATES ............................................................................... 10-1

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10.1. TEMPERATURE CONTROL CONSTRUCTION .............................................................................. 10-1

10.2. DOWNSTREAM PASSAGE CONSTRUCTION ............................................................................... 10-6

10.3. TEMPERATURE CONTROL COST ESTIMATES ............................................................................ 10-7

10.4. DOWNSTREAM PASSAGE COST ESTIMATES ........................................................................... 10-10

11. REAL ESTATE REQUIREMENTS ........................................................................................... 11-1

11.1. PROJECT AUTHORIZATION ................................................................................................... 11-1

11.2. CONSTRUCTION RIGHT-OF-WAY REQUIREMENTS ............................................................... 11-1

12. CONCLUSTIONS AND RECOMMENDATIONS .................................................................... 12-1

13. REFERENCES ............................................................................................................................ 13-1

LIST OF TABLES

Table 2-1. Detroit Dam Pertinent Data ..................................................................................................... 2-1 Table 2-2. Big Cliff Dam Pertinent Data .................................................................................................. 2-2 Table 2-3. Minimum and Maximum Gate Openings ................................................................................ 2-5 Table 2-4. Key Project Discharges for Detroit Dam ................................................................................. 2-7 Table 2-5. Detroit Dam Daily Flow Exceedance ...................................................................................... 2-7 Table 2-6. Big Cliff Dam Daily Flow Exceedance ................................................................................... 2-8 Table 2-7. Existing Condition HEC-ResSim Summary Table for Detroit and Big Cliff .......................... 2-8 Table 2-8. Maximized Power Condition, HEC-ResSim Summary Table for Detroit and Big Cliff ......... 2-9 Table 4-1. Select Life stages of Winter Steelhead and Spring Chinook and Comparison of Temperature

Targets with Literature-based Temperature Criteria (°F) .................................................................. 4-1 Table 4-2. Juvenile and Adult Salmonid Swimming Speeds .................................................................... 4-5 Table 4-3. Flows Corresponding to Regulation Goal, Action Stage and Flood Stage Level for Willamette

Control Points .................................................................................................................................... 4-8 Table 4-4. Willamette Project Flood Risk Management Benefits, 1989 to 2009 (2009 price level) ...... 4-10 Table 4-5. Detroit Dam Hourly Powerhouse Discharge Exceedance Table ........................................... 4-12 Table 4-6. FY 2006 Activity Days at Detroit Dam ................................................................................. 4-17 Table 4-7. Design Flow Rates ................................................................................................................. 4-18 Table 4-8. Submerged Telescoping Weir Scenarios ............................................................................... 4-27 Table 4-9. Energy Dissipation in SWS ................................................................................................... 4-28 Table 4-10. Lower Weir Gate Scenarios ................................................................................................. 4-29 Table 4-11. Operation of SWS ................................................................................................................ 4-31 Table 4-12. Engineering Properties of Construction Materials .............................................................. 4-34 Table 4-13. Live Loads ........................................................................................................................... 4-35 Table 4-14. Design Spectra for Seismic Loads ....................................................................................... 4-34 Table 6-1. Full Forebay Test Run and Solution Results .......................................................................... 6-8 Table 6-2. Evaluation Matrix Showing Technical Evaluation Temperature Control Alternatives ........ 6-14 Table 6-3. Evaluation Matrix Showing Biological Evaluation of Temperature Control Alternatives ... 6-15 Table 6-4. Evaluation Matrix Showing Economic and Other Consideration Evaluation of Temperature

Control Alternatives ......................................................................................................................... 6-16 Table 7-1. Downstream Fish Passage Alternatives ................................................................................. 7-1 Table 8-1. Parameters Used for FBW Evaluation of Chinook Passage at Detroit Dam ........................... 8-4 Table 8-2. Preliminary FBW Results ........................................................................................................ 8-6 Table 8-3. Evaluation Matrix Showing Technical Evaluation of Downstream Fish Passage Alts ........... 8-8 Table 10-1. Summary of Significant Features and Construction Requirements ...................................... 10-1 Table 10-2. Cost Summary for Temperature Control Options ............................................................... 10-7 Table 10-3. Elevations of Significant Features of Proposed Structures .................................................. 10-8

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Table 10-4. Elevations of Significant Features of Existing Dam ............................................................ 10-8 Table 10-5. Estimated Annual Operation and Maintenance (O&M) Costs .......................................... 10-10 Table 10-6. Cost Summary for Downstream Passage Options ............................................................. 10-10

LIST OF FIGURES

Figure 1-1. Willamette River Basin Project Location Map ...................................................................... 1-2 Figure 2-1. Section View of Detroit Dam ................................................................................................. 2-2 Figure 2-2. Interior View of Detroit Dam ................................................................................................. 2-3 Figure 2-3. Detroit Dam Rule Curve ........................................................................................................ 2-6 Figure 3-1. Observed Water Temperatures in Detroit Reservoir and Project Outlet Elevations (feet) .... 3-2 Figure 3-2. Schematic Depicting the Influence of Typical Dam Operations on Downstream Water

Temperatures Pre- and Post-Operational Temperature Control ......................................................... 3-3 Figure 3-3. Temperature Control Profile for Existing Equipment, Existing Operations and Existing Rule

Curve .................................................................................................................................................. 3-4 Figure 3-4. Total Dissolved Gas Saturation Measured Downstream of Detroit and Big Cliff Dams, June-

September 2009 ................................................................................................................................. 3-6 Figure 3-5. Life History Timing of Reservoir Entry and Fork Length from Breitenbush River .............. 3-7 Figure 3-6. Life History Timing of Reservoir Entry and Fork Length from North Santiam River .......... 3-8 Figure 3-7. Comparison of Growth Rates between North Santiam River In-stream and Reservoir Rearing

Subyearling Chinook Salmon ............................................................................................................ 3-9 Figure 3-8. Comparison of Direct Survival (48 hrs) of Juvenile Salmon Passed Through Spillway, Turbine and RO at Detroit Dam ....................................................................................................... 3-10 Figure 3-9. Vertical Distribution of Smolt-size Fish and Forebay Water Temperature (°C) at the Forebay

Dam Face Presented Separately by the Four Distinct Pool Elevation Periods ................................ 3-11 Figure 3-10. Forebay Abundance Index ................................................................................................. 3-12 Figure 3-11. Estimated Total Daily Passage of Smolt-size Fish at Turbines (PH), Spillway (SW) and

Regulating Outlet (RO) from February 20, 2011 through February 12, 2012 ................................. 3-13 Figure 4-1. Avoided Flood Damage Attributed to Detroit Dam ............................................................. 4-10 Figure 4-2. Net Generation for Detroit and Big Cliff (MWh) ................................................................ 4-11 Figure 4-3. Detroit Hourly Power Operations for the Months of January - June ................................... 4-13 Figure 4-4. Detroit Hourly Power Operations for the Months of July - December ................................ 4-14 Figure 4-5. Detroit Project Visits, FY 2001-2010................................................................................... 4-15 Figure 4-6. Detroit Lake Camper and Day User Count, FY 2001-2010 ................................................. 4-16 Figure 4-7. Average Monthly Visits to Detroit, FY 2006-2010 ............................................................. 4-16 Figure 4-8. Typical Submerged Rectangular Weir ................................................................................. 4-26 Figure 4-9. Percent of Temperature Control Flow to Lower Inlet .......................................................... 4-30 Figure 4-10. Floating Surface Outlet Section ......................................................................................... 4-31 Figure 4-11. Detached SWS ................................................................................................................... 4-32 Figure 4-12. Floating Screen Structure ................................................................................................... 4-40 Figure 4-13. FSO Structure ..................................................................................................................... 4-43 Figure 4-14. Attached Concrete Structure .............................................................................................. 4-44 Figure 4-15. Spectra data from AMEC Geomatrix and Quest (2009) .................................................... 4-45 Figure 4-16. Foundation Explorations in Foundation Area for Temperature Control Structure Excerpt from Field Drawing #115 ................................................................................................................. 4-48 Figure 5-1. Water Temperature Control Alternatives ............................................................................... 5-1 Figure 5-2. Schematic of SWS Used Over Glen Canyon Dam Turbine Intakes ...................................... 5-2 Figure 5-3. Downstream Temperatures for Existing Equipment, Existing Rule Curve and Existing

Operations .......................................................................................................................................... 5-3

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Figure 5-4. Downstream Temperatures for Existing Equipment, Existing Rule Curve and No Powerhouse Priority Operations ............................................................................................................................. 5-3

Figure 5-5. Downstream Temperatures for Existing Equipment, Delayed Drawdown 45 Days (Modified Rule Curve) and No Minimum Outflow or Powerhouse Priority Operations .................................... 5-4

Figure 5-6. Downstream Temperature for Run-of-River, Operating Year-round at Minimum Conservation Pool .............................................................................................................................. 5-4

Figure 5-7. Downstream Temperatures for Floating and Sliding Outlet Down to Elevation 1340 Feet (Upper RO Elevation), Existing Rule Curve and Existing Operations .............................................. 5-5

Figure 5-8. Downstream Temperatures for Floating and Fixed Outlet at Elevation 1403 Feet (Penstock Elevation), Existing Rule Curve and Existing Operations ................................................................. 5-5

Figure 5-9. Downstream Temperatures for Floating and Fixed Outlet at Elevation 1340 feet (Upper RO Elevation), Existing Rule Curve and Existing Operations ................................................................. 5-6

Figure 5-10. Downstream Temperatures for Floating and Fixed Outlet at Elevation 1340 feet (Upper RO Elevation), Existing Rule Curve, Minimum 400 cfs Surface Withdrawal, and No Powerhouse Priority ............................................................................................................................................... 5-6

Figure 5-11. CFD Model of SWS Over Penstock Only ............................................................................ 5-7 Figure 5-12. Line Drawing of SWS Over Penstock Only ......................................................................... 5-8 Figure 5-13. Line Drawing of SWS Over RO Only.................................................................................. 5-9 Figure 5-14. Line Drawing of SWS Over Test Conduit Only ................................................................ 5-10 Figure 5-15. Line Drawing of SWS Over All Openings ......................................................................... 5-11 Figure 5-16. Floating Withdrawal Structure at Jackson Hydropower Plant ........................................... 5-14 Figure 5-17. Typical Section of Gate Retrofit within Tainter Gate ........................................................ 5-15 Figure 5-18. Upstream and Downstream Elevations of Gate Retrofit within Tainter Gate .................... 5-16 Figure 5-19. Conceptual Temperature Control Curtain .......................................................................... 5-17 Figure 5-20. Downstream Temperatures for Single-sliding Outlet to Elevation 1340 feet, Existing Rule

Curve and Existing Operations ........................................................................................................ 5-18 Figure 6-1. Reservoir Conditions Developed from Observed Inflow Water Temperatures Representing

“Cool/Wet” Weather Conditions ....................................................................................................... 6-2 Figure 6-2. Reservoir Conditions Developed from Observed Inflow Water Temperatures Representing

“Hot/Dry” Weather Conditions .......................................................................................................... 6-3 Figure 6-3. Reservoir Conditions Developed from Observed Inflow Water Temperatures Representing

“Normal” Weather Conditions ........................................................................................................... 6-4 Figure 6-4. Detroit CFD Model Domain ................................................................................................ 6-6 Figure 6-5. Detroit CFD Forebay Model Extent ..................................................................................... 6-6 Figure 6-6. Full Forebay Polyhedral Grid at Detroit Dam before Splitting into Region Layers ............ 6-7 Figure 6-7. Region Boundaries (layers) .................................................................................................... 6-9 Figure 6-8. Region Boundaries (layers) .................................................................................................... 6-9 Figure 6-9. Region Boundaries (layers) at North Santiam Inlet ............................................................. 6-10 Figure 6-10. Upstream Boundary Locations ........................................................................................... 6-11 Figure 6-11. Downstream Boundaries Used as Outlets in CFD Baseline ............................................... 6-12 Figure 6-12. Various Layers at Face of Dam .......................................................................................... 6-12 Figure 7-1. Conceptual Drawing of FSC with No Nets, Alternative DSP-1A ........................................ 7-3 Figure 7-2. Conceptual Drawing of FSC with Partial Nets, Alternative DSP-1B .................................. 7-4 Figure 7-3. Conceptual Drawing of FSC with Full Depth Nets and Partial Outlet Coverage, Alternative

DSP-1C .............................................................................................................................................. 7-6 Figure 7-4. Conceptual Drawing of FSC with Full Depth Nets and Full Outlet Coverage, Alternative

DSP-1D .............................................................................................................................................. 7-7 Figure 7-5. Conceptual Drawing of Selective Withdrawal Structure, Alternative DSP-2 ........................ 7-9 Figure 7-6. Conceptual Drawing of Selective Withdrawal Structure with Weir Box, Alt DSP-3 .......... 7-13 Figure 7-7. Conceptual Drawing of SWS with FSS, Alternative DSP-4 ................................................ 7-17

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Figure 9-1. Location Plan View of Detroit Dam Forebay Including SWS and FSS Components ........... 9-2 Figure 9-2. Isometric View of Selective Withdrawal Structure with Weir Box ....................................... 9-4 Figure 9-3. Detailed Plan View of Detroit Dam Forebay Including SWS and FSS Components ............ 9-8 Figure 9-4. Conceptual Plan and Profile of FSS System .......................................................................... 9-9

LIST OF APPENDICES

Appendix A Pertinent Data Appendix B Temperature Modeling Appendix C Hydraulics and Hydrology Appendix D Structural and Seismic Appendix E Economics Appendix F Fish Benefits Workbook Appendix G Cost Appendix H Reference Drawings

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ACRONYMS AND ABBREVIATIONS

°C degrees Centigrade °F degrees Fahrenheit AASHTO American Association of State and Highway Transportation Officials ACI American Concrete Institute AISC American Institute of Steel Construction ASCE American Society of Civil Engineers ATU Accumulated Thermal Unit AWS American Welding Society BiOp Biological Opinion BPA Bonneville Power Administration CE-QUAL-W2 Hydrodynamic and Water Quality Model in 2D (longitudinal-vertical) CFD Computational Fluid Dynamics cfs cubic feet per second CI confidence interval CIDH cast-in-drilled hole CIP cast-in-place cm centimeter(s) COMPASS Comprehensive Passage model COP Configuration and Operations Plan DDR Design Documentation Report DO dissolved oxygen EDC engineering during construction EDR Engineering Documentation Report EM Engineering Manual ER Engineering Regulation ESA Endangered Species Act ETL Engineering Technical Letters FBW Fish Benefits Workbook FCRPS Federal Columbia River Power System FY fiscal year fps feet per second FRM flood risk management FSC floating surface collector FSS floating screen structure ft foot (feet) ft2 square feet

February 2017 7 ft³ cubic feet ft/s feet per second GB gravity base GQAR Government Quality Assurance Representative HA hydro-acoustic HEC-ResSim Hydrologic Engineering Center Reservoir System Simulation HMT Hatchery Management Team HOR head-of-reservoir IBC International Building Code (IBC) IRRM Interim Risk Reduction Measures JSATS Juvenile Salmon Acoustic Telemetry System klf kips per linear foot km kilometer(s)

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ACRONYMS AND ABBREVIATIONS (continued) lb/ft3 pounds per cubic foot lb/in3 pounds per cubic inch MCE maximum considered earthquake Mm millimeter(s) MSL mean sea level MW megawatt MWh megawatt hour(s) NGVD29 National Geodetic Vertical Datum of 1929 NMFS National Marine Fisheries Services O&M operations and maintenance ODFW Oregon Department of Fish and Wildlife OMET Operational Measures Evaluation Team OMBIL Operations and Maintenance Business Information Link PDT Product Development Team PFMA Potential Failure Mode Analysis PGA peak ground acceleration PMF probable maximum flood POR period of record psf pounds per square foot QAP Quality Assurance Plan RFP request for proposal RM river mile(s) RM&E research, monitoring and evaluation RO regulating outlet RPA Reasonable and Prudent Action S1 1.0-second spectral acceleration Ss short-period (0.2-second) spectral acceleration SIMPAS Simulated Fish Passage model SLAM Species Life-cycle Analysis Modules SWS selective withdrawal structure TCD temperature control device TCS temperature control structure

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TDG total dissolved gas TM Technical Manual UFC Unified Facilities Criteria USACE U.S. Army Corps of Engineers USGS U.S. Geological Survey USFWS U.S. Fish and Wildlife Service UWR Upper Willamette River VSP Viable Salmonid Population (model) WATER Willamette Action Team for Ecosystem Restoration WFOP Willamette Fish Operations Plan WY water year

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1. INTRODUCTION

1.1. PURPOSE AND SCOPE

The Biological Opinion (BiOp) for the Willamette River (NMFS 2008) identified a Reasonable and Prudent Alternative (RPA) to avoid jeopardy of Endangered Species Act (ESA) listed fish. Measure

4.12.3 of the RPA (Detroit downstream passage) requires downstream fish passage at Detroit Dam by 2023. Measure 5.2 of the RPA requires the Action Agencies to minimize water quality effects associated with operations of Detroit and Big Cliff dams by making structure modifications or major operational changes. Further, measure 5.2 directs, “if feasible and more efficient to achieve both purposes through one construction project, the Action Agencies will include downstream fish passage in this effort, rather than delaying it until 2023, as stated in RPA measure 4.12.3.”

The objective is to prepare an Engineering Documentation Report (EDR), or alternatives study, that addresses the feasibility of and project-specific alternatives for achieving long-term temperature control (e.g., using existing equipment with upgrades, or with a new permanent facility) that can provide target water temperatures for listed fish species in the North Santiam River and minimize the number of total dissolved gas (TDG) exceedances in the North Santiam River. An evaluation of downstream fish passage alternatives, which could operate in conjunction with long-term temperature control, is included in this report. The EDR develops a broad range of temperature control structures, downstream fish passage alternatives and TDG reduction alternatives; evaluate, reduce, and refine the alternatives; and present relative costs. Potential requirements and costs to model and prototype field test alternatives are also part of the scope.

1.2. PROJECT AUTHORIZATION

The construction of the Detroit Dam and Reservoir, North Santiam River, Oregon, was authorized by the Flood Control Act approved June 28, 1938 (Public Law 761, House Resolution No. 10618). The law approved the general comprehensive plan for flood control, navigation, and other purposes in the Willamette River Basin as set forth in House Document Numbered 544, Seventh-fifth Congress, Third session. The Flood Control Act approved June 30, 1948 (Public Law No. 858, Eightieth Congress, Second session) modified the Flood Control Act of June 28, 1938, to provide for the installation of hydroelectric power-generating facilities at Detroit Dam, and included the construction of Big Cliff Reregulating Dam and Reservoir as a part of the Detroit project, in accordance with plans on file in the Office, Chief of Engineers.

As authorized by law, the U.S. Army Corps of Engineers (USACE) is responsible for the construction and operation of the project for its primary purposes, which included flood risk management (FRM), navigation, consumptive water use, and power production; and in carrying out these functions has basic jurisdiction over all project areas including withdrawn National Forest lands. The use or utilization of withdrawn National Forest lands for purposes extraneous to project operation remains under the jurisdiction of the U.S. Forest Service. In order to facilitate the management and control of project resources and to eliminate the overlapping of administrative responsibilities, the operational area at Detroit Dam and the Big Cliff project lands lying outside the National Forest boundary will remain under the exclusive control of the USACE. The responsibility for administering all other project lands within the National Forest boundary for recreation, fire protection, and land management is vested with the U.S.

Forest Service in accordance with a Memorandum of Understanding between the U.S. Department of Agriculture and the U.S. Department of Army, effective November 10, 1954.

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1.3. PROJECT LOCATION

Detroit and Big Cliff dams are two of the 13 multi-purpose projects operated by the USACE in the Willamette River Basin (Figure 1-1). Located in Marion County in the rugged mountain forests below Mt. Jefferson, the two dams store the waters of the North Santiam subbasin, which drains about 760 square miles. Detroit Dam is located at river mile (RM) 60.9 on the North Santiam River, about 50 miles southeast of Salem, Oregon. Big Cliff is a re-regulating dam located at RM 58.1, about 3 miles downstream from Detroit Dam. Big Cliff Lake is used to even out peak discharges of water used for power generation at Detroit Dam and thus, controls downstream river level fluctuations. Detroit and Big Cliff dams were both constructed without adult fish ladders. The Minto Fish Collection Facility, located at RM 55 about 4 miles downstream of Big Cliff, was rebuilt to provide trap and haul facilities to allow for reintroduction of spring Chinook salmon and steelhead above Detroit Dam.

Figure 1-1. Willamette River Basin Project Location Map

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2. DESCRIPTION OF CURRENT PROJECT FEATURES

2.1. PERTINENT DATA

Detroit Dam is a concrete gravity structure that is 450-feet high and 1,457-feet long. The dam has a gated spillway structure that is 28.0-feet high and 294.5-feet long, and has six spill bays each 42-feet wide. The spillway crest is at elevation 1,541.0 feet, full pool is at elevation 1,569.0 feet, and minimum conservation pool is at elevation 1,450.0 feet. Additionally, Detroit Dam has four regulating outlets (ROs), two with an invert elevation at 1265.3 feet, two at elevation 1340.0 feet (Table 2-1), and two turbines with penstock intake elevation at 1403 feet. Fact sheets and pertinent data tables are included in Appendix A for Detroit and Big Cliff dams.

Table 2-1. Detroit Dam Pertinent Data

Date Completed 1953 Stream North Santiam River River Mile 60.9 (from Santiam mouth) Drainage Area (square miles) 438 Dam Height (feet) 450 Dam Crest [elevation feet mean sea level (MSL)] 1,579.0 Maximum Pool 1574.0 feet (472,600 acre-feet) Full Pool 1569.0 feet (455,100 acre-feet) Maximum Conservation Pool 1563.5 feet (436,000 acre-feet) Spillway Crest 1541.0 feet (363,200 acre-feet) Minimum Conservation Pool 1450.0 feet (154,400 acre-feet) Minimum Power Pool 1425.0 feet (115,000 acre-feet)

Turbines Two 50 MW Francis turbines at penstock elevation 1403.0 feet (4,300- 5,300 cfs combined hydraulic capacity). Cavitation limit is between 1,100-1,000 cfs per unit within normal pool operations range.

Spillway Gates Six radial Tainter gates (176,000 cfs combined hydraulic capacity) Upper Regulating Outlets Two at elevation 1340 feet (13,050 cfs combined capacity)

Test Flume Conduit One at elevation 1340 feet (same dimensions as Upper Regulating Outlet, not currently used)

Lower Regulating Outlets Two at elevation 1265 feet that are not used

Big Cliff Dam is 280-feet long and 172-feet high. The spillway crest is at elevation 1,161.5 feet, full pool is at elevation 1,206 feet and minimum pool is at elevation 1,182 feet. The dam has three spill bays and one 18 megawatt (MW) capacity power generating unit (Table 2-2). Due to Big Cliff re-regulation operations, the lake level fluctuates as much as 24 feet daily.

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Table 2-2. Big Cliff Dam Pertinent Data

Date Completed 1953 Stream North Santiam River River Mile 58.1 (from Santiam mouth) Drainage Area (square miles) 452 Dam Height (feet) 172 Dam Crest (elevation feet MSL) 1,212.0 Maximum Pool 1,210.0 feet (5,300 acre-feet) Full Pool 1,206.0 feet (4,700 acre-feet) Minimum Power Pool 1,182.0 feet (2,300 acre-feet) Turbines One 18 MW Kaplan (2,800-3,200 cfs hydraulic capacity) Spillway Gates Three radial Tainter gates (179,000 cfs combined hydraulic capacity)

A section view of Detroit Dam is shown in Figure 2-1 and an interior view of the dam, including water passage routes, is shown in Figure 2-2. Provisions for two test facilities were included in the design and construction of Detroit Dam: a test chute and a test conduit. These two test facilities are discussed below. Both facilities are in mothball status, each would require upgrades and maintenance before they could be used for the original design intent.

Figure 2-1. Section View of Detroit Dam

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Figure 2-2. Interior View of Detroit Dam

2.1.1. Prototype Test Facilities at Detroit Dam - Test Chute

A test chute capable of providing 24,000 cubic feet per second (cfs) flow, consisting of a 42-foot, constant-width chute approximately 400 feet long was provided by constructing an intermediate training wall to isolate spillway bay 6 (adjacent to the powerhouse) from the rest of the spillway. The training walls were outfitted with electrodes at 50-foot intervals for use in measuring velocity. Three observation windows were also installed on the outside wall of the chute for visual observation of the subsurface flow conditions. A movable footbridge, capable of moving up and down the test chute, spans the test chute and rides on rails on top of the training walls.

The purpose of the high-velocity test chute was to measure the amount of bulking effect on the depth of flow that occurs in a full-scale, high-head, spillway chute due to entrainment of air and to attempt to relate the observed data to depth and velocity of flow. The results would then be compared to those obtained by scale models in order to determine if a correlation can be established for spillway design purposes. The effect of air entrainment on velocity of flow would also be studied.

While portions of the test chute remain in place (observation windows and training walls), the facility has been abandoned.

2.1.2. Prototype Test Facilities at Detroit Dam - Test Conduit

A test conduit capable of providing up to 4,000 cfs and up to 318.5 feet of static head was provided by constructing an 8-foot diameter conduit on the left side of the stilling basin. The intake is at elevation 1340 feet (same intake elevation and shape as upper ROs) and the conduit terminates at elevation 1245 feet along the left wall of the stilling basin. Emergency closure is provided by a single slide gate at

90% EDR - February 2017 2-4 elevation 1340 feet (ROs have emergency gate and operating gates at elevation 1340 feet). A regulating valve was provided along the top of the stilling basin wall (elevation 1245 feet) to throttle flow through the test conduit.

When designed/implemented at Detroit, the prime advantage of the test conduit is the ability of the facility to provide high head for testing purposes, which would produce prototype cavitation pressures without the need for vacuum tanks. The original primary purpose of the test conduit was to test high-head control valves with particular emphasis on cavitation pressure, effects of venting, elimination of vibration, and determination of downpull forces on gate lips. Because of the head and discharge available with the test facility, the test conduit was also used to test concrete composition on relative resistance to erosion, the length of steel liners required downstream of regulating gates, and design of transition from rectangular gates to a circular tunnel. A Feasibility Assessment was completed in May 2003 under a contract with the Office of Naval Research to determine whether a High Speed Drag Reduction Experiment could be located in the test conduit at Detroit Dam. The assessment revealed much of the test conduit would need to be refurbished and portions would need to be replaced in order to carry out the tests.

While portions of the test conduit remain in place, the facility has not operated in more than 30 years and has been abandoned. Stoplogs are in place on the upstream inlet (similar to RO bulkhead location) which may require diver assistance if they are to be removed.

Currently, a prime advantage of the test conduit is that the facility provides an existing route through the dam that could presumably be modified or adapted for a volitional fish passage bypass system. The test conduit is not used to meet FRM requirements; therefore it provides an existing passageway through the dam that would only require modification, and not require drilling through the dam.

2.2. OPERATIONAL RESTRICTIONS

2.2.1. Minimum and Maximum Spillway Gate Openings

Operational restrictions are in place on spillway tainter gates for various reasons; a minimum gate opening is used for spillway tainter gates to avoid conditions where vibrations (driven by flow conditions at small gate openings) could cause excessive wear and/or damage to the gate, and a maximum gate opening is used for all spillway gates to ensure flow control is maintained at the gate (avoid approaching condition where weir flow is possibly bypassing the spillway gate).

Guidance is clear on maximum gate opening for tainter gates; 0.625 times the head on the weir crest (Engineer Manual (EM) 1110-2-1603). This is to avoid the condition where larger scale lower frequency cyclical loading as a result of control transitioning between the gate and the ogee crest occurs.

Furthermore, this avoids the condition where flow can transition between controlled flow (orifice flow under the gate) and uncontrolled flow (weir flow on ogee, not controlled by the gate). See Table 2-3.

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Table 2-3. Minimum and Maximum Gate Openings

Head Above Spillway Crest (feet)

Minimum Gate Opening (feet)

Maximum Gate Opening (feet)

1 0.1 0.6 5 0.26 3.1 10 0.47 6.3 15 0.66 9.4 20 0.86 12.5 25 1.06 15.6 30 1.27 18.8 40 1.68 25.0

Guidance is explicit for minimum gate openings for tainter gates. When the gate opening is too small, a hydraulic instability occurs around the gate lip and hydraulic control shifts around the gate lip. This instability can cause the flow to fluctuate and the gate to vibrate. In Table 2-3, the minimum gate openings have been set at the gate opening for each pool elevation, where a 5% change in velocity produces a change in velocity head equal to the gate opening. Specific studies or tests can be used to refine the minimum gate openings, if deemed necessary in the future. These restrictions are applicable at both Detroit and Big Cliff dams.

2.2.2. Minimum/Maximum RO Gate Openings for Detroit

The ROs at Detroit Dam, both upper and lower, consist of one emergency and one operating slide gate, located near the axis of the dam, installed in each RO conduit. Each slide gate measures 5 feet, 8 inches in width and 10 feet in height. Due to a combination of the air demand characteristics of slide gates and air bulking downstream of the slide gates, the RO gates may only be operated between 10%-80% open, or fully open. Therefore, the minimum gate opening for the RO at Detroit is 1 foot. Throttled flow is allowed for gate openings between 1 and 8 feet. Fully open (10-foot gate opening) operation is allowed, but flow may not be throttled between 8- to 10-foot gate openings.

2.2.3. Maximum Head on RO Gate for Throttled Flow for Detroit

The RO conduits at Detroit Dam were designed to operate with partial gate openings up to a head of 200 feet with full gate opening only for a head in excess of 200 feet. However, it is believed that by maintaining open channel flow downstream from the regulating gates at all times the gates might be operated satisfactorily with partial gate openings at a head…