Snell Estates dam
Snell Estates
Snell Estates, also known as Snells Nursery, is a private property located in Carroll County, Maryland, specifically in the city of Mt Airy. This recreational dam, completed in 1979, serves the primary purposes of flood risk reduction and recreation. The dam, classified as an Earth type with stone core, stands at a height of 14 feet and has a length of 1400 feet. The reservoir created by the dam has a storage capacity of 83 acre-feet, with a surface area of 12 acres and a drainage area of 0.3 square miles.
Despite its low hazard potential, Snell Estates dam is in poor condition as of the latest assessment in April 2021. The inspection frequency is set at every 5 years, with the last inspection conducted in February 2019. The dam's risk assessment is classified as moderate, indicating a level 3 risk. While the dam is not owned or funded by any federal agency, it is regulated and permitted by the Maryland Dam Safety agency, with inspection, enforcement, and permitting services provided by the state.
Water resource and climate enthusiasts interested in Snell Estates will find it to be an intriguing site for both recreational activities and flood risk management. The dam's location along Offstream-Middle Run, its design by Weller Assoc., and its proximity to the Baltimore District of the US Army Corps of Engineers make it a significant landmark in the area. However, the dam's poor condition and moderate risk level highlight the importance of continued monitoring and maintenance to ensure the safety and functionality of this vital water resource infrastructure in Carroll County, Maryland.
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 Snell Estates -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Morgan Run Near Louisville | 24 cfs | → |
| Cattail Creek Near Glenwood | 16 cfs | → |
| Patuxent River Near Unity | 15 cfs | → |
| Beaver Run Near Finksburg | 13 cfs | → |
| Monocacy River At Jug Bridge Near Frederick | 237 cfs | → |
| North Branch Patapsco River At Cedarhurst | 55 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Snell Estates.
Boat launches
- Piney Run Park
- Lakeview Avenue Carroll County
- Liberty Road Carroll County
- Frederick
- 99 Drop Howard County
- Clarksburg Road Germantown
Campgrounds
- Little Bennett Campground
- Little Bennett Regional Park
- Turner Farm
- Gambrill State Park
- Indiant Flats Campsite
- Manor Area - Cunningham Falls State Park
Track Snell Estates 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 Snell Estates
Where does the data for Snell Estates 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 Snell Estates.