Quadrant Lake No 1 is a gravity dam located in King County, Washington, built in 1994. It carries a Low hazard potential classification.
Dam profile
NID height · 8 ft8 ft tall and 180 ft long. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic concrete gravity section and the water level is illustrative.
About Quadrant Lake No 1
The primary purpose of Quadrant Lake No 1 is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Federal Way Nat' Lit League (private). It impounds the Offstream near Federal Way.
The dam stands 8 feet tall and stretches 180 feet across, creates a reservoir covering 57 acres, has a maximum storage capacity of 113 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1994, the structure is 32 years old.
This dam has a low hazard potential classification, meaning that failure would cause minimal damage, limited primarily to the dam owner's property, with no expected loss of life.
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Location
| State | Washington |
| County | King |
| Nearest City | Federal Way |
| River/Stream | Offstream |
| Coordinates | 47.29775, -122.32499 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 8 ft |
| Dam Length | 180 ft |
| Year Completed | 1994 (32 years old) |
Storage & Hydraulics
| NID Storage | 113 acre-ft |
| Max Storage | 113 acre-ft |
| Normal Storage | 57 acre-ft |
| Surface Area | 57 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 480 cfs |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | Federal Way Nat' Lit League |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | WA01740 |
| Federal ID | WA01740 |
| More Info | State Dam Safety Program |