Lake Anne Dam dam
Lake Anne Dam
Lake Anne Dam in Fairfax, Virginia, is a privately owned structure that serves primarily for recreation purposes while also providing flood risk reduction benefits. Standing at a height of 47 feet and stretching 590 feet in length, this earth dam holds a storage capacity of 745 acre-feet and covers a surface area of 24.8 acres. It is situated on the TR-Colvin Run waterway within the Baltimore District of the US Army Corps of Engineers jurisdiction.
Managed by the Department of Conservation and Recreation in Virginia, Lake Anne Dam has a satisfactory condition assessment with a high hazard potential. Despite being last inspected in February 2021, the dam meets state regulations and undergoes regular inspections to ensure its structural integrity and safety measures are up to standard. With a drainage area of 0.91 square miles and a normal storage capacity of 363 acre-feet, Lake Anne Dam plays a crucial role in water resource management in the region.
For water resource and climate enthusiasts, Lake Anne Dam presents an intriguing case study of a privately owned structure that serves both recreational and flood risk reduction purposes. With its significant storage capacity and high hazard potential, the dam's management by the Department of Conservation and Recreation ensures that it meets state regulations and undergoes regular inspections to maintain its structural integrity. As a vital component of the TR-Colvin Run water system, Lake Anne Dam highlights the importance of proper maintenance and oversight in ensuring the safety and functionality of water infrastructure in the face of changing climate conditions.
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 Lake Anne Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Difficult Run Near Great Falls | 7 cfs | → |
| Broad Run Near Leesburg | 24 cfs | → |
| Potomac River Near Wash | 1,980 cfs | → |
| Seneca Creek At Dawsonville | 114 cfs | → |
| Long Branch Near Annandale | 1 cfs | → |
| Accotink Creek Near Annandale | 2 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Lake Anne Dam.
Boat launches
See all →
Campgrounds
See all →
Fishing spots
See all →
River runs
See all →
About Lake Anne Dam
Where does the data for Lake Anne 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 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.