Agate Dam


Agate Dam is a zoned earthfill embankment about 13 miles northeast of Medford, Oregon, on Dry Creek. The structure has a height of 86 feet and a crest length of 3,800 feet and contains 421,000 cubic yards of material. The reservoir behind the dam has a total capacity of 4,800 acre-feet (active 4,780 acre-feet).


Agate Dam is in a narrow valley with steep slide slopes. The left abutment juts out into the valley and at a height of 50 feet above the stream flattens off into a bench. Ice or glacial deposits, causing ice or glacial melt water to discharge, once blocked the stream channel over a bench a few hundred feet behind the left abutment. A channel developed which extends from this rock bench to a point in the present channel a few hundred feet downstream from the dam site. Bedrock at the lowest point of the old channel is about 15 feet above the reservoir flow line. Overburden at the flow line on the right abutment consisted of 28 feet of gravel with excess sand and silt. Boulders were hard, fresh andesite 2 to 3 feet in diameter. Much of the over burden between flow line and the valley flow was undoubtedly quite permeable.  

RegionFacilities in Pacific Northwest | Pacific Northwest Home Page
ProjectRogue River Basin
Dam Type Zoned Earthfill
WatercourseDry Creek
Location11 miles NW of Medford
Original Construction1965-1966
Modified Construction
National ID NumberOR00422
Hydrologic Unit Code

Structural Height86.0 ft
Hydraulic Height (Normal Operating Depth at Dam)68.0 ft
Top Parapet (Elevation)
Spillway Crest Elevation1514.0 ft
Crest Elevation1520.0 ft
Crest Length3800.0 ft
Crest Width
Base Width
Volume of Dam Construction Materials
Streambed at Dam Axis1446.0 ft
Top of Exclusive Flood Control Pool (Elevation)
Top of Joint Use Pool (Elevation)
Top of Active Conservation Pool (Elevation)1510.0 ft
Top of Inactive Conservation Pool (Elevation)1467.0 ft
Top of Dead Storage Pool (Elevation)1465.0 ft

Hydraulics & Hydrology
Total Water Storage at Elevation 4,780 ac-ft
Maximum Water Surface Elevation
Normal Water Surface Elevation1467.0 ft
Spillway Type Uncontrolled bathtub
Auxiliary SpillwayNo
Spillway Capacity at Elevation3500 cfs at 1514.0 ft
Auxiliary Spillway Capacity at Elevation
Uncontrolled Spillway Capacity at Elevation
Outlet Works Capacity at Elevation78 cfs at 1514.0 ft
Diversion Capacity at Elevation
Drainage Area13.0 sq mi
Hydrometeorological Report (HMR)HMR 57
Probable Maximum Flood (PMF) Report

Contact Information
TitleArea Office Manager
OrganizationColumbia-Cascades Area Office
Address1917 Marsh Road
CityYakima, WA 98901-2058
Phone (Fax)509 454-5611
Phone (Office)509 575-5848 x202
OrganizationRogue River Valley Irrigation District
Address3139 Merriman Road
CityMedford, OR 97501-1277
Phone (Office)541 773-6127

Last updated: Jun 17, 2015