Mongaup dam
Mongaup
Mongaup is a captivating hydroelectric dam located on the Mongaup River in Sullivan, New York. Built in 1925 by Chas. T. Main, Inc., this gravity dam stands at a height of 45 feet and has a length of 384 feet, providing a maximum storage capacity of 1779 acre-feet. With a surface area of 120 acres and a drainage area of 158 square miles, Mongaup has a maximum discharge capacity of 34,000 cubic feet per second.
Operated by the Federal Energy Regulatory Commission, Mongaup's primary purpose is hydroelectric power generation. The dam is equipped with an uncontrolled spillway with a width of 164 feet and is considered to have a high hazard potential. Although its condition assessment is not available, the dam is inspected annually to ensure its safety and integrity. In case of emergencies, an Emergency Action Plan is in place, meeting guidelines and last revised in November 2020.
Mongaup's rich history, strategic location, and significant contribution to hydroelectric power generation make it a prominent feature in New York's water resource infrastructure. Climate and water resource enthusiasts will find Mongaup an intriguing site, as it embodies the intersection of engineering ingenuity, environmental stewardship, and sustainable energy production.
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 Mongaup -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Mongaup River Near Mongaup Ny | 205 cfs | → |
| Mongaup River At Mongaup Valley Ny | 65 cfs | → |
| Shohola Creek Near Walker Lake | 58 cfs | → |
| Neversink River At Bridgeville Ny | 136 cfs | → |
| Neversink River At Godeffroy Ny | 300 cfs | → |
| Delaware R Above Lackawaxen R Nr Barryville Ny | 2,590 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Mongaup .
Boat launches
- Plank Road Town Of Forestburgh
- Starlight Road 55, Monticello
- Matamoras
- Butler Court Town Of Mamakating
- Zane Grey
- Town Of Mamakating
Track Mongaup 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 Mongaup
Where does the data for Mongaup 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 Mongaup .