Transcript MF Project Enhancements Workshop

Middle Fork Project
Project Description
April 25, 2006
http://relicensing.pcwa.net
Middle Fork American River
Hydroelectric Project

Provide a Project Overview

Describe Major Project Features

Describe Supporting Infrastructure

Discuss Operating Constraints

Describe General Operations and Maintenance

Summary of Recreation Facilities

Questions
April 2006
1
MFP - Overview

Developed as a Water Supply and
Generation Project

Initial Operation 1967

224 MW Nameplate Generating Capacity

120,000 Acre-Feet Water Supply

Operated by Placer County Water Agency

PG & E Acquires Power Output
April 2006
2
Major Project Features

Two Large Dams and Storage Reservoirs

Two Medium Dams and Reservoirs
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Three Small Dams and Diversion Pools

Five Powerhouses

Five Tunnels
April 2006
3
Supporting Infrastructure

Electrical Switchyards and Substation
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Access Roads and Trails

Communication and Power Lines
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Stream Gages

Maintenance and Dormitory Facilities
April 2006
4
Duncan Creek Diversion

Spillway Crest - 5,265 ft Elevation

Diversion - Concrete Gravity - 165 ft Long
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Diversion Capacity - 400 cfs

Surface Area - Approximately 1 Acre

Gross Storage - 20 Acre-Feet
April 2006
5
Duncan Creek - Middle Fork Tunnel

1.5 Miles Long

10 ft Horseshoe Cross-Section

Capacity 400 cfs*

Intake With Trash Rack
April 2006
6
French Meadows Dam
and Reservoir
April 2006
7
French Meadows Dam
and Reservoir



Spillway Crest at 5,273 ft Elevation
French Meadows Dam - Gravel and Earthfill 2,700 ft Long
Surface Area - 1,404 Acres Maximum,
434 Minimum

Gross Storage - 134, 993 Acre-Feet

Shoreline - 9 Miles
April 2006
8
French Meadows - Hell Hole Tunnel

2.6 miles long

12.3 ft Horseshoe Cross-Section

Capacity 400 cfs*


Intake in French Meadows Reservoir and Trash
Rack
Terminates in a 6.25 ft Diameter - 691 ft Long
Penstock to the French Meadows Powerhouse
April 2006
9
French Meadows Powerhouse
April 2006
10
French Meadows Powerhouse


Located on Hell Hole Reservoir
Water Supply - Discharge from French Meadows
- Hell Hole Tunnel
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Single Francis Turbine
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15.3 MW / 60,000 Volts
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Discharges to Hell Hole Reservoir
April 2006
11
Hell Hole Dam and Reservoir
April 2006
12
Hell Hole Dam and Reservoir

Spillway Crest at 4,650 ft Elevation

Hell Hole Dam - Rockfill - 1,570 ft Long

Surface Area - 1,253 Acres Maximum, 185 Acres
Minimum

Gross Storage - 207,500 Acre-Feet

Shoreline - 11 Miles
April 2006
13
Hell Hole Powerhouse
April 2006
14
Hell Hole Powerhouse

Located at Outlet from Hell Hole Dam

Water Supply - Hell Hole Dam Discharge Conduit

Single Francis Turbine

0.725 MW / 12,000 Volts

Discharges to Rubicon River
April 2006
15
Hell Hole - Middle Fork Tunnel

10.4 Miles Long

13.5 ft Horseshoe Cross-Section

Capacity 920 cfs*

Intake in Hell Hole Reservoir

Terminates in a 9 - 7.5 ft dia. - 3,653 ft Long
Penstock to the Middle Fork Powerhouse
April 2006
16
North Fork Long Canyon Creek
Diversion
April 2006
17
North Fork Long Canyon Creek
Diversion

Dam Crest at 4,720 ft Elevation

Diversion - Concrete Gravity - 120 ft Long

Diversion Capacity 100 cfs

Surface Area - Less than 1 Acre

Pipe and Shaft to the Hell Hole - Middle Fork
Tunnel
April 2006
18
South Fork Long Canyon Creek
Diversion
April 2006
19
South Fork Long Canyon Creek
Diversion

Dam Crest at 4,650 ft Elevation

Diversion - Concrete Gravity - 145 ft Long

Diversion Capacity 200 cfs

Surface Area - Less than 1 Acre

Pipe and Shaft to the Hell Hole - Middle Fork
Tunnel
April 2006
20
Middle Fork Powerhouse
April 2006
21
Middle Fork Powerhouse

Located on Middle Fork Interbay Reservoir

Water Supply- Hell Hole - Middle Fork Tunnel
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Two Pelton Waterwheels
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122.4 MW / 60,000 Volts

Discharges to Middle Fork Interbay Reservoir
April 2006
22
Middle Fork Interbay Dam
and Reservoir
April 2006
23
Middle Fork Interbay Dam
and Reservoir

Dam Crest at 2,536 ft Elevation

Interbay Dam - Concrete Gravity - 233 ft Long

Surface Area - 7 Acres

Gross Storage - 175 Acre-Feet
April 2006
24
Middle Fork Tunnel
Ralston Tunnel

6.7 Miles Long

13.5’ Horseshoe Cross-Section

Capacity 924 cfs*


Intake in Middle Fork Interbay Reservoir / Trash
Rack
Terminates in a 9.5 - 8 ft dia. - 1,670 ft Long
Penstock to the Ralston Powerhouse
April 2006
25
Ralston Powerhouse
April 2006
26
Ralston Powerhouse


Located on Ralston Afterbay Reservoir
Water Supply - Middle Fork Tunnel - Ralston
Tunnel

Single Francis Turbine

79.2 MW / 60,000 Volts

Discharges to Ralston Afterbay
April 2006
27
Ralston Afterbay and Afterbay Dam
April 2006
28
Ralston Afterbay and Afterbay Dam



Dam Crest at 1,189 ft Elevation
Ralston Afterbay Dam - Concrete Gravity 560 ft Long
Gross Storage - 2,782 Acre-Feet
April 2006
29
Ralston - Oxbow Tunnel

0.1 Miles Long

13.25 ft Horseshoe Cross-Section

Capacity 1,075 cfs*


Intake in Ralston Afterbay Reservoir / Trash
Rack
Supplies Oxbow Powerhouse
April 2006
30
Oxbow Powerhouse
April 2006
31
Oxbow Powerhouse

Located on Middle Fork American River

Single Francis Turbine

Generator - 6.1 MW / 60,000 Volts

Discharges to Middle Fork American River below
Ralston Afterbay Dam
April 2006
32
Other Project Components

Project Power and Communication Lines
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Stream Gaging Stations
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Project Roads and Trails
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Microwave Reflector Stations and Radio Towers

Support Facilities
April 2006
33
Project Operations

Operating Constraints
 Water Rights (Storage and Diversion
Allowances)
 Minimum Pool Requirements
 Stream Maintenance Flows (i.e. Minimum
Instream Flows)
 Dam / Diversion Discharge Capacities
April 2006
34
Minimum Pool Requirements
MINIMUM POOL
French Meadows
Reservoir
Hell Hole
Reservoir
Duncan Creek
Diversion
April 2006
Forecast / Folsom
Reservoir (a/f)
> 2,000,000
1,200,000 – 2,000,000
< 1,200,000
Minimum Pool (a/f)
Oct-May
June-Sept
50,000
60,000
25,000
60,000
8,700
28,000
Forecast / Folsom
Reservoir (a/f)
> 2,000,000
1,200,000 – 2,000,000
< 1,200,000
Minimum Pool (a/f)
Oct-May
June-Sept
50,000
70,000
25,000
70,000
5,500
26,000
Maintain water surface elevation at 5,259 feet elev.
35
Minimum Instream Flow Requirements
MINIMUM INSTREAM FLOW
Forecast / Folsom Reservo
Duncan Creek
Forecast / Folsom
Reservoir (a/f)
> 1,000,000
< 1,000,000
Release (cfs)
Lessor of 8 or natural flow
Lessor of 4 or natural flow
Forecast / Folsom Reservo
Forecast / Folsom
French Meadows
Reservoir (a/f)
Reservoir
> 1,000,000
< 1,000,000
Hell Hole
Reservoir
April 2006
Release (cfs)
8 at all times
4 at all times
Forcast / Folsom
Reservoir (a/f)
> 1,000,000 a/f
Release (cfs)
May 15 – Dec 14
20
Dec 15 – May 14
10
< 1,000,000 a/f
10
6
36
June 1 – Oct 14
Oct 15 – May 31
Minimum Instream Flow Requirements
MINIMUM INSTREAM FLOW
Forecast / Folsom
Forecast / Folsom
South Fork Long Reservoir (a/f)
Canyon
Diversion Dam
> 1,000,000
< 1,000,000
North Fork Long
Canyon
Diversion Dam
April 2006
Release (cfs)
lesser of 5 or natural flow
lesser of 2.5 or natural flow
Releases to maintain stream
flow of 2 cfs or the natural
flow, whichever is less, shall
be made at all times.
37
Minimum Instream Flow Requirements
MINIMUM INSTREAM FLOW
Middle Fork
Interbay
Forecast / Folsom
Reservoir (a/f)
> 1,000,000
< 1,000,000

Oxbow
April 2006

Release (cfs)
lesser of 23 or natural flow
lesser of 12 or natural flow
Releases shall be 75 cfs at all times as measured
downstream of the confluence with the North Fork
of the Middle Fork.
Such releases shall not cause vertical fluctuations
(measured in representative section) greater than 3
feet per hour.
38
Dam and Diversion Discharges

Duncan Creek Diversion


French Meadows Dam
April 2006

Stream Maintenance Pipe
10 inch diameter
8 cfs*
Sluice Pipe
60 inch diameter
Stream Maintenance Pipe
8 inch diameter
8 cfs*
Low Level Outlet
6 feet diameter
1,430 cfs
60 inch diameter ring jet valve
39
Dam and Diversion Discharges


Hell Hole Dam

April 2006
Stream Maintenance Pipe
16 Inch diameter
20 cfs*
Howell-Bunger Valve
Discharge Conduit
48 inch Diameter
852 cfs*
Howell-Bunger Valve
Powerhouse Water Supply
20 inch diameter
30 cfs*
40
Dam and Diversion Discharges

Stream Maintenance Pipe
12 Inch diameter
2 cfs*

Stream Maintenance Pipe
12 Inch diameter
5 cfs*

Stream Maintenance Pipe
20 inch diameter
23 cfs*
Howell-Bunger Valve
Sluice Pipe
60 inch diameter
890 cfs
North Fork Long Canyon Creek Diversion
South Fork Long Canyon Diversion
Middle Fork Interbay

April 2006
41
MFP Operations



April 2006
Operated to Meet Water Supply
Requirements
Operated to Meet Minimum Instream
Flow Requirements
Operated to Optimize Value of Generation
42
Operations Overview

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
April 2006
43
Seasonal Pattern of Operations


Reservoir Storage:
 French Meadows and Hell Hole Reservoirs,
343,000 Acre-Feet Total Storage
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)
April 2006
44
Reservoir Operations



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Operations during refill period to meet demands, fill
reservoirs, avoid spill
Operations during drawdown to meet demands, hit
end-of-year storage target
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
April 2006
45
Generation Scheduling




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
Project typically operates in “peaking” mode:
8-16 hours per day, during the most valuable
time periods
Annual generation approximately 1 million
MW hours.
April 2006
46
Scheduling and Operations


Project operations have been much the same
since the construction of the Project
Variation in specific operations practices through
time in response to:
 Project maintenance requirements
 Changes in California power markets
 Recreation demands downstream of the
Project
April 2006
47
Maintenance

Facility Testing (powerhouse equipment testing
and maintenance, gate and valve testing)
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Debris Removal Management
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Sediment Management
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Vegetation and Pest Management
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Facility Painting

Road Maintenance
April 2006
48
Recreation Facilities



Recreation Plan developed as required by the
license
Recreation Facilities include campgrounds, picnic
areas, boat launch areas, and one scenic vista
Operated by the Tahoe and Eldorado National
Forests
April 2006
49
Recreation Sites

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)
April 2006
50
Recreation Sites

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 Picnic Area

South Fork Long Canyon
 One single-unit and one group campground
(Big Meadows and Middle Meadows Group)
April 2006
51