Stillwell dam
Stillwell
Stillwell, also known as Stilwell Lake, is a concrete gravity dam located in the Town of Highlands, Orange County, New York. Built in 1948 by the US Army, the dam serves primarily for flood risk reduction but also supports fish and wildlife pond management, recreation, and water supply purposes. Standing at a height of 62 feet and spanning 480 feet in length, Stillwell has a storage capacity of 4,038 acre-feet and covers a surface area of 133 acres, with a drainage area of 12 square miles.
Managed by the US Army, Stillwell is regulated by the New York State Department of Environmental Conservation and undergoes regular state permitting, inspection, and enforcement processes. With a controlled spillway width of 200 feet and high hazard potential, the dam is classified as very high risk (Category 1). Despite its critical role in flood risk reduction, the condition assessment of Stillwell is currently not available, highlighting the importance of ongoing monitoring and maintenance to ensure the safety and integrity of this essential water resource infrastructure.
Located in the Highlands Range Area U1, Stillwell is a key feature on the Popolopen Creek, under the jurisdiction of the Philadelphia District of the US Army Corps of Engineers. As a vital component of water resource management in the region, Stillwell demonstrates the intersection of federal, state, and local agencies in safeguarding water supply, flood protection, and environmental conservation efforts in New York State.
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 Stillwell -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Croton R @ New Croton Dam Nr Croton-On-Hudson Ny | 218 cfs | → |
| Muscoot River At Baldwin Place Ny | 14 cfs | → |
| Mahwah River Near Suffern Ny | 5 cfs | → |
| Muscoot River Below Dam At Amawalk Ny | 31 cfs | → |
| Ramapo River At Ramapo Ny | 66 cfs | → |
| West Branch Croton River At Richardsville Ny | 3 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Stillwell .
Boat launches
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Campgrounds
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Fishing spots
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River runs
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About Stillwell
Where does the data for Stillwell 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 below 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.
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.