44Total Dams
13High Hazard
6Significant
Dam Safety in Grant County, Washington
Grant County has 44 dams tracked in the National Inventory of Dams. Of these, 13 are classified as high hazard — meaning failure would probably cause loss of human life. Another 6 carry a significant hazard classification. Currently, 2 dams have a condition assessment of poor or unsatisfactory.
The average dam in Grant County is 46 years old. The most common purpose is other. The tallest dam is O'sullivan Dam at 200 ft.
Explore more: Oldest dams in Washington · Tallest dams · High risk dams · Largest reservoirs
| Dam | Hazard | Condition | Height (ft) | Purpose | Year |
|---|---|---|---|---|---|
| O'sullivan Dam | High | Not assessed | 200 | Flood Risk Reduction | 1949 |
| Priest Rapids | High | Fair | 187 | Hydroelectric | 1961 |
| North Dam | High | Not assessed | 145 | Flood Risk Reduction | 1951 |
| Pinto Dam | High | Not assessed | 130 | Flood Risk Reduction | 1948 |
| Dry Falls Dam | High | Not assessed | 123 | Flood Risk Reduction | 1949 |
| Chiawana Frenchman Hills Dam | High | Fair | 24 | Irrigation | 1995 |
| Ob-3 Warden Digester Lagoon | High | Satisfactory | 21 | Other | 2018 |
| Koehn Ranch Reservoir | High | Satisfactory | 19 | Irrigation | 2009 |
| Chiawana Rd O Sw Pond | High | Not assessed | 16 | Irrigation | 2019 |
| Lawrence Orchards Dam | High | Fair | 13 | Irrigation | 1995 |
| Partridge Ranch Dam | High | Satisfactory | 12 | Irrigation | 2010 |
| Evans Desert Aire Pond | High | Satisfactory | 9 | Irrigation | 1990 |
| Coulee City Wastewater Lagoon | High | Satisfactory | 7 | Other | 1997 |
| Quincy Sludge Storage Lagoon System Lagoons 1 2 and 3 | Significant | Fair | 15 | Other | 1986 |
| Coulee City Wastewater Lagoon Cell 4 | Significant | Satisfactory | 15 | Other | 2008 |
| Quincy Aerated Lagoon No 2 | Significant | Not assessed | 12 | Other | 1987 |
| Quincy Aerated Lagoon No 1 | Significant | Not assessed | 12 | Other | 1987 |
| Quincy Brine Evaporation Ponds | Significant | Fair | 11 | Other | 1989 |
| Ingredion Process Water Lagoon | Significant | Satisfactory | 9 | Other | 2000 |
| Soda Lake Dike | Low | Not assessed | 59 | Irrigation | 1952 |
| Nestle Potato Effluent Lagoon | Low | Not assessed | 32 | Other | 1994 |
| Port of Moses Lake Lagoon | Low | Not assessed | 30 | Other | 1999 |
| Columbia Marsh Unit #1 Dam | Low | Poor | 25 | Fish and Wildlife Pond | 1958 |
| Simplot Lrar Lagoon | Low | Not assessed | 24 | Other | 2006 |
| Rec Silicon Wastewater Pond | Low | Fair | 23 | Other | 2009 |
| Moses Lake South Dam | Low | Not assessed | 20 | Irrigation | 1961 |
| Pacific Nw Sugar Co Condensation Pond | Low | Not assessed | 19 | Other | 1998 |
| Moses Lake North Dam | Low | Not assessed | 19 | Irrigation | 1930 |
| Carnation Waste Pond No 7 | Low | Not assessed | 16 | Other | 1979 |
| Pacific Nw Sugar Co Sedimentation Pond | Low | Not assessed | 15 | Other | 1998 |
| Smith Brothers Dairy Storage Lagoon | Low | Not assessed | 15 | Other | 2001 |
| Columbia Marsh Unit #2 Dam | Low | Fair | 15 | Fish and Wildlife Pond | 1957 |
| Lindblad Brothers Dam | Low | Fair | 14 | Flood Risk Reduction | 1940 |
| Higginbotham Reservoir Dam | Low | Not assessed | 13 | Irrigation | 1947 |
| Lyon Lake Dam | Low | Not assessed | 13 | Recreation | 1971 |
| Moran Slough Dike | Low | Satisfactory | 13 | Hydroelectric | 1964 |
| Columbia Marsh Unit #1 Pond No. 3 Dam | Low | Poor | 13 | Fish and Wildlife Pond | 1958 |
| Mcdonald Dam | Low | Not assessed | 12 | Flood Risk Reduction | 1924 |
| Alkali Lake | Low | Not assessed | 12 | Recreation | 1950 |
| Rearing Pond Dike | Low | Not assessed | 12 | Fish and Wildlife Pond | 1964 |
| Crab Creek Flood Flat Water Control Structure | Low | Not assessed | 11 | Fish and Wildlife Pond | 2024 |
| Merry Dam | Low | Not assessed | 10 | Recreation | 1976 |
| Lenice Dam | Low | Not assessed | 10 | Recreation | 1976 |
| George City Wastewater Treatment Lago | Low | Not assessed | 9 | Other | 1996 |