Lake Nessmuk (Pa-601) dam
Lake Nessmuk (Pa-601)
Lake Nessmuk (Pa-601) in Tioga, Pennsylvania, is a state-owned recreational lake built in 1968 for flood risk reduction and leisure activities. The earth dam, standing at 52.2 feet tall and 870 feet long, holds a storage capacity of 1453 acre-feet with a surface area of 60 acres. The dam's spillway type is uncontrolled and has a width of 166 feet, making it a critical structure with a high hazard potential.
Managed by the Pennsylvania Department of Environmental Protection, Lake Nessmuk is regularly inspected and found to be in satisfactory condition as of April 2020. The dam's risk assessment is moderate, with an overall risk rating of 3. Despite its moderate risk, the dam meets guidelines for emergency action plans, although specifics on preparedness and inundation maps are not provided in the data. The surrounding area is under the jurisdiction of the state, ensuring that regulatory agencies oversee the proper maintenance and operation of the dam to protect the community downstream along the Morris Branch Marsh Creek.
With its scenic location in Delmar Township and its primary purpose of recreation, Lake Nessmuk offers both a tranquil retreat for visitors and a crucial infrastructure for flood risk reduction. As climate change continues to impact water resources, the maintenance and regulation of dams like Lake Nessmuk become increasingly important to ensure the safety and enjoyment of those who rely on its services.
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 Nessmuk (Pa-601) -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Straight Run | 1 cfs | → |
| Crooked Cr Bl Catlin Hollow At Middlebury Center | 163 cfs | → |
| Tioga River Near Mansfield | 349 cfs | → |
| Tioga River At Tioga | 2,050 cfs | → |
| Corey Creek Near Mainesburg | 15 cfs | → |
| Pine Creek At Cedar Run | 2,470 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Lake Nessmuk (Pa-601).
Boat launches
Campgrounds
- Hills Creek State Park
- Leonard Harrison State Park
- Colton Point State Park
- Twin Streams Campground
- Ives Run
- Hoffman Campground
Track Lake Nessmuk (Pa-601) 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 Nessmuk (Pa-601)
Where does the data for Lake Nessmuk (Pa-601) 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 Nessmuk (Pa-601).