Pertinent Data

General
Location:
	State County River River Mile Township Range Section Latitude Longitude	Washington Garfield and Whitman Snake 107.5 14 N 43 E 32 46° 39' 37" 117° 25' 37"
River miles from mouth of Snake River		107.5
River miles upstream from Little Goose Dam		37.2
Owner	U.S. Army Corps of Engineers, Walla Walla District
Authorized Purpose	Power generation and inland navigation
Other Uses	Flood control (maintain levee freeboard at Lewiston), fishery, and recreation
Type of Project		Run-of-river
Real Estate:
Fee acquisition land above pool elevation 738, acres		9,224

Reservoir
Name		Lower Granite Lake1
Elevations (Feet Mean Sea Level):
	Maximum at dam for spillway design flood Normal operating range at confluence gage (RM 139.5) Minimum at dam for standard project flood	746.5 738 to 733 724
Length, miles:
	Snake River (to Asotin damsite, RM 146.8) Clearwater River	39.3 4.6
Length of shoreline, miles		91
Average width, miles		0.3
Maximum width, miles		0.6
Surface area at elevation 738 (low flow, flat pool), acres		8,900
Storage below flat pool elevation 738, acre-feet		483,800
Storage below flat pool elevation 733, acre-feet		440,200
Storage between elevation 733 and 738		43,600
Height normal high pool to tailwater elevation 638 (low flow, 30,000 cfs or less), feet		100

Levees
Top width, feet		12
Slopes, waterside and landside		1V on 2H
Materials	Gravel and earth fill with impervious core
Top elevation	5 feet above backwater profile for standard project flood
Embankment length, miles:
	Lewiston	8.6
Installed pumping capacity, cfs:
	Lewiston levees	450.4

Dam (General)
Axis (Lambert)		N 32° 00'E
Length and Widths, feet:
	Dam total length at crest North abutment embankment South non-overflow monoliths Spillway overall length Spillway to powerhouse non-overflow Powerhouse overall length Spillway to navigation lock non-overflow Navigation lock overall width at foundation Navigation lock overall width at deck	3,200 1,435 32.2 512 43.4 656 43.4 304 186
Concrete Heights, feet:
	Maximum overall concrete height (powerhouse sump deck to deck) Maximum non-overflow monoliths height: North Central South Maximum lock wall monolith height (culverts to deck)	254 151 166 181 191
Deck elevations, feet msl:
	Intake, spillway bridge, non-overflow sections, and upstream end of navigation lock Downstream end of navigation lock South shore fish ladder Tailrace and fishwater intake North abutment embankment	751 746 656 656 756

Spillway
Number of Bays		8
Overall length, feet (abutment centerlines)		512
Deck elevation, feet msl		751
Ogee crest elevation, feet msl		681
Flip lip elevation		630
Control gates:
	Type Size	Tainter 50'W x 60'H
Gantry crane (joint use with powerhouse) capacity, tons		100
Stilling basin length, feet		188
Stilling basin elevation, feet msl		580
Maximum design capacity, cfs		850,000

Powerhouse
Length overall, feet		656
Spacing, feet:
	Units 1 through 5 Unit 6 Erection and service bay	90 96 110
Width overall, transverse section, feet		243.17
Intake deck elevation, feet msl		751
Tailrace deck elevation, feet msl		656
Maximum height (draft tube invert to intake deck), feet		228
Turbines:
	Type Runner diameter, inches Revolutions per minute Rating horsepower Distributor centerline elevation	Kaplan, 6-blade 312 90 212,400 599
Generators:
	Rating (nameplates), kilowatts Power factor Kilovolt ampere rating	135,000 0.95 142,100
Units installed complete initially		3
Skeleton units provided initially		3
Total units now installed		6
Plant capacity, nameplate rating, kilowatts		810,000
Crane capacities, tons:
	Intake (joint use with spillway) Bridge Draft tube gantry	100 600 50

Navigation Lock and Channels
Net clear length, lock chamber, feet		674
Net clear width, lock chamber, feet		86
Upstream gate:
	Type Height, feet	Submersible tainter 23
Downstream gate:
	Type Height, feet	Miter 122
Operating water surface elevations in chamber		633 to 738
Maximum operating lock lift, feet		105
Lift, feet (riverflow 300,000 cfs, practical navigation limit)		88.2
Length of guidewalls (from face of gate), feet:
	Upstream (floating) Downstream	750 700
Downstream approach channel:
	Width, feet Bottom elevation	250 617
Minimum tailwater elevation		633.0
Lower lock sill elevation, feet		618.0
Upper lock sill elevation, feet		718.0
Maximum depth over sills, feet		20.0
Minimum depth over sills, feet		15.0

Abutment Embankment
Embankment elevation		756
Embankment top width, feet		45
Material	Gravel fill with rock facing, impervious silt core
	Upstream Downstream	Combination sand and gravel filters Gravel and sand filters
Slope, upstream		1V on 2H
Slope, downstream		1V on 2H

Fish Facilities 2
Upstream migrants fish ladder:
	Number of fish ladders Slope Weir 634 to Weir 627 Weir 728 to Weir 737 Ladder clear width, feet Design capacity, cfs	1 1V on 10H 1 V on 32H 20 75
Exit Channel:
	Location Top of trashrack Invert Width, feet	Between weir 737 and pool in non-overflow section El. 732 El 727 6
Alternative exit channel (pool elevation below 727):
	Exit pipe to reservoir	18-inch-diameter full plastic pipe down to El. 718, and a half-round plastic pipe down to El. 710
Operating elevations:
Design range:
	Pool elevations Tailwater elevations Riverflow	733 to 738 633 to 642 0 to 225,000 cfs
Maximum operating range:
	Pool elevations Tailwater elevations Riverflow	732 to 739 633 to 645.4 0 to 340,000 cfs
Adult fish trap and handling facility		1
Pumps for fishway system attraction water:
	Number Capacity, cfs	3 3,150
Downstream migrants bypass system:
	Design pool range Design capacity, cfs Extended-length Submerged Bar Screens Vertical barrier fish screens Orifices from bulkhead and fish screen slots: Number Size (diameter in inches) Fingerling collection gallery Fingerling transportation pipe	733 to 738 200 to 250 18 18 36, 36 10, 12 1 1
Fingerling holding and sampling facility		1
Fingerling transportation facilities:
	Truck loading facility Barge loading facility	1 1

Hydrologic Data (Based on streamflow data for the Snake River near Clarkston, Washington)
Drainage area, square miles		103,200
Period of Record	October 1915 to September 1972 (Discontinued in December 1972)
Discharges, cfs:
	Instantaneous maximum of record, 29 May 1948 Instantaneous minimum of record, 2 September 1958 Average annual flow Average annual mean daily peak flow	369,000 6,660 50,300 188,300
Extreme outside period of record:
	Flood of June 1894 Flood of June 1894, controlled by existing projects	409,000 295,000
Standard project flood, controlled by existing projects:
	Snake River below Clearwater River Snake River above Clearwater River Clearwater River above Snake River	420,000 295,000 150,000
Spillway design flood		850,000