Lake Antietam dam
Lake Antietam
Lake Antietam, located in Lower Alsace Township, Pennsylvania, is a vital water supply source with a primary purpose of providing water to the local community. The earth dam, standing at a height of 60 feet and stretching 230 feet in length, was completed in 1880 and has a storage capacity of 430 acre-feet. The dam's normal storage capacity is 310 acre-feet, covering a surface area of 16 acres and serving a drainage area of 5.4 square miles.
Managed by the Pennsylvania Department of Environmental Protection, Lake Antietam is regulated, inspected, and enforced to ensure its structural integrity and operational safety. The dam has a high hazard potential but is currently assessed as satisfactory in condition. Despite its age, the dam continues to meet guidelines for emergency action plans, although specific dates for assessments and management measures are not provided in the data.
With its historical significance and crucial role in providing water to the region, Lake Antietam serves as a reminder of the importance of maintaining and safeguarding water resources in the face of changing climate conditions. The dam stands as a testament to the engineering feats of its time and the ongoing efforts to protect communities from potential hazards associated with water infrastructure.
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 Lake Antietam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Schuylkill River At Reading | 641 cfs | → |
| Tulpehocken Creek Near Reading | 94 cfs | → |
| Manatawny Creek Near Spangsville | 33 cfs | → |
| Tulpehocken Cr At Blue Marsh Damsite Near Reading | 70 cfs | → |
| Maiden Creek Near Virginville | 70 cfs | → |
| Schuylkill River At Berne | 713 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Lake Antietam.
Boat launches
- Reading Riverfront Park
- Epler's Landing
- Wall Street Leesport
- Scott's Run Lake-French Creek State Park
- Hopewell Lake-French Creek State Park
- Sheidy Road
Track Lake Antietam 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 Lake Antietam
Where does the data for Lake Antietam 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 Lake Antietam.