Middle Fork Project Project Description April 25, 2006

1 April 2006 Middle Fork American River Hydroelectric Project Provide a Project Overview Provide a Project Overview Describe Major Project Features Describe Major Project Features Describe Supporting Infrastructure Describe Supporting Infrastructure Discuss Operating Constraints Discuss Operating Constraints Describe General Operations and Maintenance Describe General Operations and Maintenance Summary of Recreation Facilities Summary of Recreation Facilities Questions Questions

2 April 2006 MFP - Overview Developed as a Water Supply and Generation Project Developed as a Water Supply and Generation Project Initial Operation 1967 Initial Operation MW Nameplate Generating Capacity 224 MW Nameplate Generating Capacity 120,000 Acre-Feet Water Supply 120,000 Acre-Feet Water Supply Operated by Placer County Water Agency Operated by Placer County Water Agency PG & E Acquires Power Output PG & E Acquires Power Output

3 April 2006 Major Project Features Two Large Dams and Storage Reservoirs Two Large Dams and Storage Reservoirs Two Medium Dams and Reservoirs Two Medium Dams and Reservoirs Three Small Dams and Diversion Pools Three Small Dams and Diversion Pools Five Powerhouses Five Powerhouses Five Tunnels Five Tunnels

4 April 2006 Supporting Infrastructure Electrical Switchyards and Substation Electrical Switchyards and Substation Access Roads and Trails Access Roads and Trails Communication and Power Lines Communication and Power Lines Stream Gages Stream Gages Maintenance and Dormitory Facilities Maintenance and Dormitory Facilities

5 April 2006

6 Duncan Creek Diversion Spillway Crest - 5,265 ft Elevation Spillway Crest - 5,265 ft Elevation Diversion - Concrete Gravity ft Long Diversion - Concrete Gravity ft Long Diversion Capacity cfs Diversion Capacity cfs Surface Area - Approximately 1 Acre Surface Area - Approximately 1 Acre Gross Storage - 20 Acre-Feet Gross Storage - 20 Acre-Feet

7 April 2006 Duncan Creek - Middle Fork Tunnel 1.5 Miles Long 1.5 Miles Long 10 ft Horseshoe Cross-Section 10 ft Horseshoe Cross-Section Capacity 400 cfs* Capacity 400 cfs* Intake With Trash Rack Intake With Trash Rack

8 April 2006 French Meadows Dam and Reservoir

9 April 2006 French Meadows Dam and Reservoir Spillway Crest at 5,273 ft Elevation Spillway Crest at 5,273 ft Elevation French Meadows Dam - Gravel and Earthfill - 2,700 ft Long French Meadows Dam - Gravel and Earthfill - 2,700 ft Long Surface Area - 1,404 Acres Maximum, 434 Minimum Surface Area - 1,404 Acres Maximum, 434 Minimum Gross Storage - 134, 993 Acre-Feet Gross Storage - 134, 993 Acre-Feet Shoreline - 9 Miles Shoreline - 9 Miles

10 April 2006 French Meadows - Hell Hole Tunnel 2.6 miles long 2.6 miles long 12.3 ft Horseshoe Cross-Section 12.3 ft Horseshoe Cross-Section Capacity 400 cfs* Capacity 400 cfs* Intake in French Meadows Reservoir and Trash Rack Intake in French Meadows Reservoir and Trash Rack Terminates in a 6.25 ft Diameter ft Long Penstock to the French Meadows Powerhouse Terminates in a 6.25 ft Diameter ft Long Penstock to the French Meadows Powerhouse

11 April 2006 French Meadows Powerhouse

12 April 2006 French Meadows Powerhouse Located on Hell Hole Reservoir Located on Hell Hole Reservoir Water Supply - Discharge from French Meadows - Hell Hole Tunnel Water Supply - Discharge from French Meadows - Hell Hole Tunnel Single Francis Turbine Single Francis Turbine 15.3 MW / 60,000 Volts 15.3 MW / 60,000 Volts Discharges to Hell Hole Reservoir Discharges to Hell Hole Reservoir

13 April 2006 Hell Hole Dam and Reservoir

14 April 2006 Hell Hole Dam and Reservoir Spillway Crest at 4,650 ft Elevation Spillway Crest at 4,650 ft Elevation Hell Hole Dam - Rockfill - 1,570 ft Long Hell Hole Dam - Rockfill - 1,570 ft Long Surface Area - 1,253 Acres Maximum, 185 Acres Minimum Surface Area - 1,253 Acres Maximum, 185 Acres Minimum Gross Storage - 207,500 Acre-Feet Gross Storage - 207,500 Acre-Feet Shoreline - 11 Miles Shoreline - 11 Miles

15 April 2006 Hell Hole Powerhouse

16 April 2006 Hell Hole Powerhouse Located at Outlet from Hell Hole Dam Located at Outlet from Hell Hole Dam Water Supply - Hell Hole Dam Discharge Conduit Water Supply - Hell Hole Dam Discharge Conduit Single Francis Turbine Single Francis Turbine MW / 12,000 Volts MW / 12,000 Volts Discharges to Rubicon River Discharges to Rubicon River

17 April 2006 Hell Hole - Middle Fork Tunnel 10.4 Miles Long 10.4 Miles Long 13.5 ft Horseshoe Cross-Section 13.5 ft Horseshoe Cross-Section Capacity 920 cfs* Capacity 920 cfs* Intake in Hell Hole Reservoir Intake in Hell Hole Reservoir Terminates in a ft dia. - 3,653 ft Long Penstock to the Middle Fork Powerhouse Terminates in a ft dia. - 3,653 ft Long Penstock to the Middle Fork Powerhouse

18 April 2006 North Fork Long Canyon Creek Diversion

19 April 2006 North Fork Long Canyon Creek Diversion Dam Crest at 4,720 ft Elevation Dam Crest at 4,720 ft Elevation Diversion - Concrete Gravity ft Long Diversion - Concrete Gravity ft Long Diversion Capacity 100 cfs Diversion Capacity 100 cfs Surface Area - Less than 1 Acre Surface Area - Less than 1 Acre Pipe and Shaft to the Hell Hole - Middle Fork Tunnel Pipe and Shaft to the Hell Hole - Middle Fork Tunnel

20 April 2006 South Fork Long Canyon Creek Diversion

21 April 2006 South Fork Long Canyon Creek Diversion Dam Crest at 4,650 ft Elevation Dam Crest at 4,650 ft Elevation Diversion - Concrete Gravity ft Long Diversion - Concrete Gravity ft Long Diversion Capacity 200 cfs Diversion Capacity 200 cfs Surface Area - Less than 1 Acre Surface Area - Less than 1 Acre Pipe and Shaft to the Hell Hole - Middle Fork Tunnel Pipe and Shaft to the Hell Hole - Middle Fork Tunnel

22 April 2006 Middle Fork Powerhouse

23 April 2006 Middle Fork Powerhouse Located on Middle Fork Interbay Reservoir Located on Middle Fork Interbay Reservoir Water Supply- Hell Hole - Middle Fork Tunnel Water Supply- Hell Hole - Middle Fork Tunnel Two Pelton Waterwheels Two Pelton Waterwheels MW / 60,000 Volts MW / 60,000 Volts Discharges to Middle Fork Interbay Reservoir Discharges to Middle Fork Interbay Reservoir

24 April 2006 Middle Fork Interbay Dam and Reservoir

25 April 2006 Middle Fork Interbay Dam and Reservoir Dam Crest at 2,536 ft Elevation Dam Crest at 2,536 ft Elevation Interbay Dam - Concrete Gravity ft Long Interbay Dam - Concrete Gravity ft Long Surface Area - 7 Acres Surface Area - 7 Acres Gross Storage Acre-Feet Gross Storage Acre-Feet

26 April 2006 Middle Fork Tunnel Ralston Tunnel 6.7 Miles Long 6.7 Miles Long 13.5’ Horseshoe Cross-Section 13.5’ Horseshoe Cross-Section Capacity 924 cfs* Capacity 924 cfs* Intake in Middle Fork Interbay Reservoir / Trash Rack Intake in Middle Fork Interbay Reservoir / Trash Rack Terminates in a ft dia. - 1,670 ft Long Penstock to the Ralston Powerhouse Terminates in a ft dia. - 1,670 ft Long Penstock to the Ralston Powerhouse

27 April 2006 Ralston Powerhouse

28 April 2006 Ralston Powerhouse Located on Ralston Afterbay Reservoir Located on Ralston Afterbay Reservoir Water Supply - Middle Fork Tunnel - Ralston Tunnel Water Supply - Middle Fork Tunnel - Ralston Tunnel Single Francis Turbine Single Francis Turbine 79.2 MW / 60,000 Volts 79.2 MW / 60,000 Volts Discharges to Ralston Afterbay Discharges to Ralston Afterbay

29 April 2006 Ralston Afterbay and Afterbay Dam

30 April 2006 Ralston Afterbay and Afterbay Dam Dam Crest at 1,189 ft Elevation Dam Crest at 1,189 ft Elevation Ralston Afterbay Dam - Concrete Gravity ft Long Ralston Afterbay Dam - Concrete Gravity ft Long Gross Storage - 2,782 Acre-Feet Gross Storage - 2,782 Acre-Feet

31 April 2006 Ralston - Oxbow Tunnel 0.1 Miles Long 0.1 Miles Long ft Horseshoe Cross-Section ft Horseshoe Cross-Section Capacity 1,075 cfs* Capacity 1,075 cfs* Intake in Ralston Afterbay Reservoir / Trash Rack Intake in Ralston Afterbay Reservoir / Trash Rack Supplies Oxbow Powerhouse Supplies Oxbow Powerhouse

32 April 2006 Oxbow Powerhouse

33 April 2006 Oxbow Powerhouse Located on Middle Fork American River Located on Middle Fork American River Single Francis Turbine Single Francis Turbine Generator MW / 60,000 Volts Generator MW / 60,000 Volts Discharges to Middle Fork American River below Ralston Afterbay Dam Discharges to Middle Fork American River below Ralston Afterbay Dam

34 April 2006 Other Project Components Project Power and Communication Lines Project Power and Communication Lines Stream Gaging Stations Stream Gaging Stations Project Roads and Trails Project Roads and Trails Microwave Reflector Stations and Radio Towers Microwave Reflector Stations and Radio Towers Support Facilities Support Facilities

35 April 2006 Project Operations Operating Constraints Operating Constraints  Water Rights (Storage and Diversion Allowances)  Minimum Pool Requirements  Stream Maintenance Flows (i.e. Minimum Instream Flows)  Dam / Diversion Discharge Capacities

36 April 2006 Minimum Pool Requirements

37 April 2006 Minimum Instream Flow Requirements

38 April 2006 Minimum Instream Flow Requirements

39 April 2006 Minimum Instream Flow Requirements

40 April 2006 Dam and Diversion Discharges

41 April 2006 Dam and Diversion Discharges

42 April 2006 Dam and Diversion Discharges

43 April 2006 MFP Operations Operated to Meet Water Supply Requirements Operated to Meet Water Supply Requirements Operated to Meet Minimum Instream Flow Requirements Operated to Meet Minimum Instream Flow Requirements Operated to Optimize Value of Generation Operated to Optimize Value of Generation

44 April 2006 Operations Overview Operations Governed By: Operations Governed By:  MF Project FERC License Conditions  Water Rights Permits  Contractual Obligations (Delivery of Water and Power)  Physical Constraints (Size of Tunnels, Capacity of Powerhouses)  Power Market – High Value Periods of Operation

45 April 2006 Seasonal Pattern of Operations Reservoir Storage: Reservoir Storage:  French Meadows and Hell Hole Reservoirs, 343,000 Acre-Feet Total Storage Seasonal Pattern of Operations: Seasonal Pattern of Operations:  Store Water During Winter and Spring Precipitation and Runoff Periods (Refill Period)  Releases During the Dry Summer and Fall Months (Drawdown Period)  Reservoirs are Operated to Maintain Relative Balance between Reservoirs  Dec. 31 Carry-Over Target for Dec. 31 of 150,000 Acre-Feet (Two Reservoirs)

46 April 2006 Reservoir Operations Operations during refill period to meet demands, fill reservoirs, avoid spill Operations during refill period to meet demands, fill reservoirs, avoid spill Operations during drawdown to meet demands, hit end-of-year storage target Operations during drawdown to meet demands, hit end-of-year storage target Reservoir storage targets through the year: Reservoir storage targets through the year:  Generally based on historic practice  Refined during refill period based primarily on hydrologic conditions, with some consideration of power market conditions  Storage managed during drawdown period based on consumptive obligations and power market trends At all times meet minimum release obligations At all times meet minimum release obligations

47 April 2006 Generation Scheduling Watershed provides sufficient water to operate about half of the time at full load (50% capacity factor) Watershed provides sufficient water to operate about half of the time at full load (50% capacity factor) Full-load operations are most efficient for generation Full-load operations are most efficient for generation Project typically operates in “peaking” mode: 8-16 hours per day, during the most valuable time periods Project typically operates in “peaking” mode: 8-16 hours per day, during the most valuable time periods Annual generation approximately 1 million MW hours. Annual generation approximately 1 million MW hours.

48 April 2006 Scheduling and Operations Project operations have been much the same since the construction of the Project Project operations have been much the same since the construction of the Project Variation in specific operations practices through time in response to: Variation in specific operations practices through time in response to:  Project maintenance requirements  Changes in California power markets  Recreation demands downstream of the Project

49 April 2006Maintenance Facility Testing (powerhouse equipment testing and maintenance, gate and valve testing) Facility Testing (powerhouse equipment testing and maintenance, gate and valve testing) Debris Removal Management Debris Removal Management Sediment Management Sediment Management Vegetation and Pest Management Vegetation and Pest Management Facility Painting Facility Painting Road Maintenance Road Maintenance

50 April 2006 Recreation Facilities Recreation Plan developed as required by the license Recreation Plan developed as required by the license Recreation Facilities include campgrounds, picnic areas, boat launch areas, and one scenic vista Recreation Facilities include campgrounds, picnic areas, boat launch areas, and one scenic vista Operated by the Tahoe and Eldorado National Forests Operated by the Tahoe and Eldorado National Forests

51 April 2006 Recreation Sites French Meadows Reservoir French Meadows Reservoir  Reservoir North Shore - picnicking, camping, boat ramp and parking (McGuire, Poppy)  Reservoir East end - single-unit and group campgrounds (Lewis, Coyote Group, gates Group and Ahart)  Reservoir South Shore - picnicking, camping, boat ramp and parking (French Meadows Complex)

52 April 2006 Recreation Sites Hell Hole Reservoir Hell Hole Reservoir  Hell Hole Reservoir - scenic vista, picnicking, camping, boat ramp and parking  Big Meadows Campground  Upper Hell Hole (boat-in/hike-in campground) Ralston / Oxbow Ralston / Oxbow  Ralston Picnic Area South Fork Long Canyon South Fork Long Canyon  One single-unit and one group campground (Big Meadows and Middle Meadows Group)