Rye Patch Dam


Rye Patch Dam

Rye Patch Dam lies within a valley cut by the Humboldt River.  The materials forming the valley slopes at the damsite are variably consolidated Lahontan and  pre-Lahontan lacustrine and fluviatile deposits consisting of very thinly-bedded to thickly-bedded gravel, sand, silt, and clay.  Nearly continuous outcrops of the deposits occur in the valley slopes. 

The deposits are nearly horizontal except for occasional local dips of 20 to 30 degrees south, southwest, and northwest along undulating erosional surfaces.  Locally, Holocene age slopewash (Qs) forms a 1- to 10-foot-thick clay and silt deposit on the lower half of the Humboldt River valley slopes. 

The Lahontan deposits lie above elevation 4160 on the left abutment of the dam and above elevation 4200 on the right abutment of the dam and are not part of the abutments.  The pre-Lahontan deposits (Qpl), which form the right and left abutments, include the Paiute, Rye Patch, and Lovelock Formations. 

A volcanic ash bed and a calcium-carbonated-cemented gravel bed (5 feet thick) crop out in the upper Rye Patch Formation.

Since Lake Lahontan receded from the Rye Patch Dam area about 10,000 years ago, the Humboldt River has eroded the present valley and deposited up to 40 feet of unconsolidated alluvial silt and sand (Qa).  This alluvium has been divided into six subunits based on physical characteristics.  The central portion of the dam is founded on this alluvium.

A small shear zone was revealed during dam construction.   This feature was attributed to minor slumping of pre-Lahontan deposits in the valley slopes.  No faults are recognized in the foundation or abutments.  No landslides or other major surficial slips are known to exist in the reservoir area.  No fault displacement of Lahontan or pre-Lahontan deposits are known to exist in the immediate area of the dam.

RegionFacilities in Mid-Pacific | Mid-Pacific Home Page
Dam Type
ReservoirRye Patch
WatercourseHumboldt River
Location22 mi NE of Lovelock
Original Construction1935-1936
Modified Construction
National ID NumberNV10124
Hydrologic Unit Code

Structural Height78.00 ft
Hydraulic Height (Normal Operating Depth at Dam)65 ft
Top Parapet (Elevation)
Spillway Crest Elevation4119 ft
Crest Elevation4144 ft
Crest Length1074 ft
Crest Width
Base Width
Volume of Dam Construction Materials
Streambed at Dam Axis4071.0 ft
Top of Exclusive Flood Control Pool (Elevation)
Top of Joint Use Pool (Elevation)
Top of Active Conservation Pool (Elevation)4136.0 ft
Top of Inactive Conservation Pool (Elevation)4072.5 ft
Top of Dead Storage Pool (Elevation)4072.5 ft

Hydraulics & Hydrology
Total Water Storage at Elevation
Maximum Water Surface Elevation
Normal Water Surface Elevation4136.0 ft
Spillway Type
Auxiliary SpillwayNo
Spillway Capacity at Elevation24000.0 cfs at 4136.0 ft
Auxiliary Spillway Capacity at Elevation
Uncontrolled Spillway Capacity at Elevation
Outlet Works Capacity at Elevation1000.0 cfs at 4120.0 ft
Diversion Capacity at Elevation
Drainage Area15700 sq mi
Hydrometeorological Report (HMR)HMR xx
Probable Maximum Flood (PMF) Report

Contact Information
TitleArea Office Manager
OrganizationLahontan Basin Area Office
Address705 N. Plaza Street, Room 320
CityCarson City, NV 89701
Phone (Office)775 882-3436
OrganizationPershing County Water Conservation District
AddressP.O. Box 218
CityLovelock, NV 89419
Phone (Fax)702 273-2424
Phone (Office)702 273-2293

Last updated: Jun 04, 2009