Heishmans Mill dam
Heishmans Mill
Heishmans Mill, located in West Pennsboro Township, Cumberland County, Pennsylvania, is a historic hydroelectric dam that has been operating since 1815. Owned privately, this concrete dam stands at a height of 10 feet and has a storage capacity of 80 acre-feet. It is situated on the Conodoguinet Creek and serves as a source of renewable energy for the surrounding community.
Managed and regulated by the Pennsylvania Department of Environmental Protection, Heishmans Mill is classified as a low hazard potential structure with a condition assessment that is currently not rated. The dam has a spillway type and width that are unlisted, and its last inspection took place in May 2018 with a scheduled inspection frequency of 5 years. While the emergency action plan status and risk assessment details are not provided, the dam continues to be a vital asset for water resource management in the region.
With its historical significance, operational longevity, and environmental impact as a hydroelectric facility, Heishmans Mill offers a fascinating glimpse into the intersection of water resources, climate considerations, and sustainable energy production. As enthusiasts in these fields, exploring the engineering, regulatory, and conservation aspects of this dam can provide valuable insights into the intricate balance between human development and natural resource management.
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 Heishmans Mill -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Sherman Creek At Shermans Dale | 99 cfs | → |
| Bixler Run Near Loysville | 6 cfs | → |
| Mountain Creek Near Pine Grove Furnace | 11 cfs | → |
| Conodoguinet Creek Near Hogestown | 186 cfs | → |
| Bermudian Creek At Oxford Road Nr Heidlersburg | 6 cfs | → |
| Juniata River At Newport | 2,490 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Heishmans Mill.
Boat launches
- Opossum Lake Bl #1
- Opossum Lake Bl #2
- North Middleton Park
- Letort Falls Park
- Childrens Lake B.L.
- Laurel Lake Boat Launch
Campgrounds
- Pine Grove Furnace State Park
- Primitive Campsite #4
- Primitive Campsite #6
- Primitive Campsite #7
- Primitive Campsite #5
- Primitive Campsite #8
Fishing spots
Track Heishmans Mill 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 Heishmans Mill
Where does the data for Heishmans Mill 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 Heishmans Mill.