General
Location:
State - Washington
County - Columbia and Whitman
River - Snake
River Mile - 70.3
River miles upstream from Ice Harbor Dam - 28.7

Owner - U.S. Army Corps of Engineers, Walla Walla District
Authorized Purpose - Power generation and inland navigation
Other Uses - Fishery and recreation
Type of Project - Run-of-river

Real Estate:
Fee acquisition land above pool elevation 638 - 11,179 acres

Reservoir
Name - Lake Bryan (Reference 1)
Elevations (Feet Mean Sea Level):
Maximum at dam for spillway design flood - 646.5
Normal operating range gauged at dam - 638 to 633

At Pool Elevation 638:
Length – 37.2 miles
Length of shoreline – 92 miles
Average width – 0.4 miles
Maximum width – 0.8 miles
Surface area (low flow, 30,000 cfs or less) – 10,025 acres

Storage below elevation 638 (low flow) - 565,200 acre-feet
Storage below elevation 633 (low flow) - 516,300 acre-feet
Storage between elevations 633 and 638 - 48,900 acre-feet
Height normal high pool elevation 638 to tailwater elevation 540 (low flow, 30,000 cfs or less) - 98 ft

Dam (General)
Axis (Lambert) - N 10° 57'W
Length and Widths, feet:
Dam total length at crest – 2,655 ft
North abutment embankment – 787.5 ft
North non-overflow monoliths length – 189 ft
Spillway overall length (between abutment centerline) – 512 ft
Spillway to powerhouse non-overflow – 48.5 ft
Powerhouse overall length – 656 ft
Powerhouse to navigation lock non-overflow length – 57 ft
Navigation lock overall width – 328 ft
Concrete Heights, feet:
Maximum overall concrete height (powerhouse sump deck to deck) – 253 ft
Maximum non-overflow monoliths height (north) – 200 ft
Maximum lock wall monolith height (culverts to deck) – 165 ft

Deck elevations, feet msl:
Intake, spillway bridge, non-overflow sections, and upstream end of navigation lock – 651 ft msl
Downstream end of navigation lock – 646 ft msl
South shore fish ladder – 558 ft msl
Tailrace and fishwater intake – 558 ft msl
North abutment embankment – 656 ft msl

Spillway
Number of Bays - 8
Overall length (abutment centerlines) – 512 ft
Deck elevation – 651 ft msl
Ogee crest elevation – 581 ft msl
Flip lip elevation – 532

Control gates:
Type - Tainter
Size - 50'W x 60'H

Gantry crane (joint use with powerhouse) capacity – 100 tons
Stilling basin length – 118 ft
Stilling basin elevation – 466.5 ft msl
Maximum design capacity – 850,000 cfs

Powerhouse
Length overall – 656 ft
Spacing, feet:
Units 1 through 5 – 90
Unit 6 – 96
Erection and service bay – 110
Width overall, transverse section – 243 ft
Maximum height (draft tube invert to intake deck) – 226 ft

Turbines:
Type – Kaplan, 6-blade
Runner diameter – 312 in
Revolutions per minute – 90
Rating horsepower – 212,400
Distributor centerline elevation - 501

Generators:
Rating (nameplates) – 135,000 kilowatts
Power factor – 0.95
Kilovolt ampere rating – 142,100
Units installed complete initially - 3
Skeleton units provided initially - 3
Total units now installed - 6
Plant capacity, nameplate rating – 810,000 kilowatts

Crane capacities, tons:
Intake (joint use with spillway) - 100
Bridge - 600
Draft tube gantry - 50

Navigation Lock and Channels
Net clear length, lock chamber - 668 ft
Net clear width, lock chamber - 86 ft
Operating water surface elevations in chamber - 537 to 638
Maximum operating lock lift - 101 ft

Upstream gate:
Type – Submersible tainter
Height – 22 ft

Downstream gate:
Type - Miter
Height - 85 ft

Length of guidewalls (from face of gate), feet:
Upstream (floating) - 665
Downstream - 700

Downstream approach channel:
Width – 250 ft
Bottom elevation – 521

Lower lock sill elevation - 522 ft
Upper lock sill elevation - 618 ft
Maximum depth over sills - 20 ft
Minimum depth over sills - 15 ft

Abutment Embankment
Embankment elevation - 656
Embankment top width - 43 ft

Material - Gravel ill with rock facing impervious silt core
Upstream - Combination sand and gravel filters
Downstream - Gravel and sand filters

Slope, upstream - 1V on 2H
Slope, downstream - 1V on 2H

Fish Facilities
Upstream migrants fish ladder:
Number of fish ladders - 1
Slope – 1V on 10H
Ladder clear width – 20 ft
Design capacity – 75 cfs

Exit Channel:
Location - Between weir 637 and pool in non-overflow section
Top of trashrack elevation - 632
Invert elevation - 627
Width - 6 ft

Normal operating range:
Pool elevations – 633 to 638
Tailwater elevations – 537 to 544
Riverflow – 0 to 225,000 cfs

Maximum operating range:
Pool elevations – 632 to 639
Tailwater elevations – 537 to 547.5
Riverflow – 0 to 340,000 cfs

Pumps for fish attraction water:
Number - 3
Rated capacity – 2,550 cfs

Downstream migrants:
Traveling fish screens - 18
Fingerling collection gallery - 1
Fingerling transportation pipe - 1
Fingerling handling facility - 1

Fingerling transportation facilities:
Truck loading facility - 1
Barge loading facility - 1
Design pool range - 633 to 638

Hydrologic Data
(Based on streamflow data for the Snake River near Clarkston, Washington)
Drainage area - 103,200 square miles
Period of Record - October 1915 to September 1972 (Discontinued in December 1972)

Discharges, cfs:
Instantaneous maximum of record, 29 May 1948 – 369,000 cfs
Instantaneous minimum of record, 2 September 1958 – 6,600 cfs
Average annual flow – 50,300 cfs
Average annual mean daily peak flow – 188,300 cfs
Extreme outside period of record:
Flood of June 1894 – 409,000 cfs
Flood of June 1894, controlled by existing projects – 295,000 cfs

Standard project flood, controlled by existing projects:
Snake River below Clearwater River – 420,000 cfs
Snake River above Clearwater River – 295,000 cfs
Clearwater River above Snake River – 150,000 cfs
Spillway design flood – 850,000 cfs

References
(1)For the purpose of continuity with existing Little Goose Lock and Dam documents, the use of the term "pool" or "reservoir" is used interchangeably. The term "lake" is used only to designate a geographical body of water.