Great Falls Estate Dam dam
Great Falls Estate Dam
Great Falls Estate Dam, located in Montgomery, Maryland, is a privately owned structure primarily designed for recreation and flood risk reduction along the Cool Spring Branch river. Constructed in 1963 by Robert A. Goves & Assoc., this earth dam stands at a height of 34 feet and is 300 feet long, with a storage capacity of 134 acre-feet. Despite its low hazard potential, the dam remains state-regulated and regularly inspected by Maryland Dam Safety.
With a spillway width of 18 feet and a maximum discharge of 160 cubic feet per second, Great Falls Estate Dam plays a crucial role in managing water flow and ensuring the safety of surrounding areas. The dam's risk assessment indicates a moderate level of risk, emphasizing the importance of ongoing monitoring and maintenance to prevent potential hazards. Although the condition assessment is currently not rated, the dam's emergency action plan readiness and compliance with guidelines are areas for improvement.
As a key structure in the region, Great Falls Estate Dam serves as a significant asset for both water resource management and recreational activities. With its unique design and historical significance, the dam continues to attract water resource and climate enthusiasts seeking to appreciate its engineering marvel and environmental impact on the surrounding watershed.
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 Great Falls Estate Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Difficult Run Near Great Falls | 12 cfs | → |
| Potomac River Near Wash | 2,300 cfs | → |
| Seneca Creek At Dawsonville | 40 cfs | → |
| Broad Run Near Leesburg | 21 cfs | → |
| Rock Creek At Sherrill Drive Washington | 82 cfs | → |
| Nw Branch Anacostia River Near Colesville | 3 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Great Falls Estate Dam.
Boat launches
- Potomac Hills Street Fairfax County
- Rileys Lock Road Darnestown
- Clarksburg Road Germantown
- Ashburn Village Boulevard 20585, Lansdowne
- Edwards Ferry Road Montgomery County
- Gravelly Point Boat Ramp
Campgrounds
- Swains Lock Hiker-Biker Campsite
- Marsden Tract Group Campsite
- Marsden Tract Campground
- Lake Fairfax
- Horsepen Branch
- Horsepen Branch Campsite
Fishing spots
- Washington Aqueduct
- Dalecarlia Reservoir
- Gillam Branch (Historical)
- Davis Branch (Historical)
- Maddox Branch
- Georgetown Reservoir
Track Great Falls Estate 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 Great Falls Estate Dam
Where does the data for Great Falls Estate 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 Low 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 Great Falls Estate Dam.