Garrison Creek Stormwater Detention Dam dam
Garrison Creek Stormwater Detention Dam
Located in King County, Washington, the Garrison Creek Stormwater Detention Dam stands as a vital structure designed for flood risk reduction along Garrison Creek. Owned by the local government and regulated by the Washington Department of Ecology, this earth dam with a hydraulic height of 45 feet was completed in 1991 to provide storage capacity of up to 40 acre-feet, serving a drainage area of 0.86 square miles. With a maximum discharge capacity of 307 cubic feet per second, the dam plays a crucial role in managing stormwater runoff and reducing flood hazards in the region.
The dam's strategic location within the Seattle District ensures effective flood control measures for nearby communities, with a fair condition assessment as of 2016. Despite its high hazard potential, the dam's structure and operation are continuously inspected and enforced by state authorities to ensure public safety. The dam's primary purpose of flood risk reduction aligns with its design as a multi-arch earth dam, utilizing rock and soil foundations to support its 117-foot length and 2-acre surface area. With an emergency action plan in place and regular inspections, the Garrison Creek Stormwater Detention Dam remains a crucial asset in safeguarding the local environment and residents against potential flooding events.
As climate change intensifies the frequency and severity of storms, the Garrison Creek Stormwater Detention Dam plays a pivotal role in managing stormwater and reducing flood risks in the region. With Congressman Adam Smith representing the area in Congressional District 09, Washington, the dam's importance in protecting communities and infrastructure from extreme weather events cannot be overstated. As part of the state's regulatory framework, the dam's continued operation and maintenance ensure its effectiveness in mitigating flood impacts and preserving water resources for future generations.
Dam data reference
Condition Assessment
- Satisfactory
- No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
- Fair
- No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action.
- Poor
- A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency.
- Unsatisfactory
- A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
- Not Rated
- The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Hazard Potential Classification
- High
- Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
- Significant
- Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environmental damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
- Low
- Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
- Undetermined
- Dams for which a downstream hazard potential has not been designated or is not provided.
Plan around the weather
Same NOAA / yr.no feed Snoflo's iOS app uses. Watch the precipitation column on the meteogram -- rain on the basin upstream typically lifts inflow 24-72 hours later.
Next 5 days, hour by hour
Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.
5-day forecast table
Every 3 hours, broken out across temperature, snow, rain, humidity, and wind. Each cell is colour-coded relative to the column min/max.
| Time | Condition | Temp (°F) | Snow (in) | Rain (in) | Humidity (%) | Wind (mps) | Wind dir |
|---|---|---|---|---|---|---|---|
| Loading detailed forecast… | |||||||
15-day temperature & precipitation
Daily temperatures, snow, and rain projected over the next two weeks.
Nearby streamflow gauges
USGS streamgauges around Garrison Creek Stormwater Detention Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Mill Creek At Earthworks Park At Kent | 1 cfs | → |
| Spring Brook Creek At Orillia | 6 cfs | → |
| Mill Creek Near Mouth At Orillia | 6 cfs | → |
| Cedar River At Renton | 339 cfs | → |
| Duwamish River At Golf Course At Tukwila | 6,700 cfs | → |
| Green River Near Auburn | 758 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Garrison Creek Stormwater Detention Dam.
Boat launches
- Lake Fenwick Trail Kent
- 148th Avenue Southeast Kent
- Shady Lake Boat Ramp
- King County
- Southeast Green Valley Road 12507-12565, Auburn
- North Lake Fishing Access Federal Way
Campgrounds
- Point Robinson Campground
- Dash Point State Park
- Dash Point Campground
- Kanaskat-Palmer State Park Campground
- Kanaskat Palmer Recreation Area
- Gig Harbor Rv Resort
Paddle runs
- Snoqualmie Falls To Plum's Landing
- Wagner Bridge To Confluence With Middle Fork Snoqualmie River
- Confluence With Taylor River To Confluence With North Fork Snoqualmie River
- Huckleberry Creek To Confluence With Clearwater River
- Quartz Road To Confluence With Middle Fork Snoqualmie River
- Alpine Lakes Wilderness Boundary To Quartz Creek Road
Track Garrison Creek Stormwater Detention Dam in the Snoflo app
Save this dam as a favorite and get the local NOAA / yr.no forecast plus regional flow context wherever you are.
About Garrison Creek Stormwater Detention Dam
Where does the data for Garrison Creek Stormwater Detention Dam come from?
Structural and regulatory data come from the U.S. Army Corps of Engineers' National Inventory of Dams (NID). Weather forecast comes from NOAA / yr.no -- the same feed Snoflo's iOS app uses.
How often is the report updated?
NID structural data refreshes annually as the Corps publishes updated assessments. The weather forecast refreshes throughout the day.
What does the High hazard rating mean?
The Corps of Engineers' hazard potential classification grades probable consequences if the dam fails: High = probable loss of human life; Significant = no probable loss of human life but possible economic loss / environmental damage; Low = no probable loss of human life, only minor economic / environmental losses. See the Dam Data Reference card above for the full definitions.
What's "% of normal"?
The current storage value compared to the historical average storage on this calendar day. 100% = right on average; values above 100% mean above-normal storage (wet year); values below mean below-normal (dry year or drought).
Can I get alerts when storage crosses a threshold?
Yes -- alerts are managed in the Snoflo iOS app. Favorite this dam, set a threshold, and you'll get a push the moment conditions cross.
Other water bodies near here
Snoflo-tracked reservoirs and dams within driving distance of Garrison Creek Stormwater Detention Dam.