Loch Alsh Reservoir dam
Loch Alsh Reservoir
Loch Alsh Reservoir, located in Montgomery, Pennsylvania, is a picturesque water resource managed by the local government for recreational purposes. Built in 1915, this earth dam structure stands at a height of 16 feet and has a storage capacity of 41 acre-feet. With a surface area of 6 acres and a drainage area of 0.25 square miles, the reservoir is a popular spot for outdoor enthusiasts to enjoy water-based activities.
Under the jurisdiction of the Pennsylvania Department of Environmental Protection, Loch Alsh Reservoir is regularly inspected and regulated to ensure its safety and functionality. The dam has a high hazard potential but has been assessed as satisfactory in condition, with the last inspection conducted in November 2020. While no emergency action plan (EAP) has been reported, the reservoir meets regulatory guidelines and continues to be a valuable water resource for the community.
Surrounded by the tranquility of Upper Dublin Township and fed by the Wissahickon Creek, Loch Alsh Reservoir remains a vital part of the local landscape. Its historical significance, combined with its recreational value, makes it a cherished destination for water resource and climate enthusiasts seeking to connect with nature and appreciate the beauty of Pennsylvania's diverse water ecosystems.
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 Loch Alsh Reservoir -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Wissahickon Creek At Fort Washington | 35 cfs | → |
| Pennypack Creek Trib At Hatboro | 1 cfs | → |
| L Neshaminy Cr At Valley Road Nr Neshaminy | 14 cfs | → |
| Schuylkill River At Norristown | 1,120 cfs | → |
| Pennypack Creek At Pine Road | 49 cfs | → |
| Tacony Creek At County Line | 23 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Loch Alsh Reservoir.
Boat launches
- Norristown Riverfront Park
- Betzwood
- Arcola Rd 3506, Lower Providence Township
- Frankford Arsenal
- Tacony Boat Launch
- Linden Avenue
Campgrounds
- Camp Green Lane
- Camp Sumney
- Homestead Family Campground
- Camp Delmont
- Bsa Camp Hart
- Nelson Training Center
Fishing spots
Track Loch Alsh Reservoir 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 Loch Alsh Reservoir
Where does the data for Loch Alsh Reservoir 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 Loch Alsh Reservoir.