Hannawa dam
Hannawa
Hannawa Dam, located in Potsdam, New York, is a privately owned structure on the Raquette River that serves multiple purposes, including hydroelectric power generation, fire protection, and creating a small fish pond. Built in 1902, this gravity dam stands at 34 feet tall and has a length of 255 feet, with a storage capacity of 690 acre-feet. The dam's uncontrolled spillway has a width of 216 feet and a maximum discharge of 12,700 cubic feet per second.
Managed by the Federal Energy Regulatory Commission, Hannawa Dam is inspected regularly to ensure its structural integrity and low hazard potential. Despite being considered a moderate risk structure, the dam has not had any recent condition assessments available. While the dam does not fall under state regulation or permitting, it is subject to federal oversight and enforcement. The surrounding area has a drainage area of 993 square miles and a surface area of 204 acres, making it an important water resource in the region.
Overall, Hannawa Dam is a key component in managing water resources and providing hydroelectric power in St. Lawrence County, New York. Its historical significance and multi-purpose design make it a valuable asset for the community while also highlighting the importance of infrastructure maintenance and risk management in the face of changing climate conditions. This dam serves as a reminder of the delicate balance between harnessing nature for human benefit and ensuring the safety and sustainability of our water resources for future generations.
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 Hannawa -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Raquette River At South Colton Ny | 1,050 cfs | → |
| W Br St. Regis R Nr Parishville Ny | 362 cfs | → |
| Raquette River At Raymondville Ny | 2,050 cfs | → |
| Grass River At Chase Mills Ny | 992 cfs | → |
| St. Regis River At Brasher Center Ny | 1,150 cfs | → |
| Oswegatchie River Near Heuvelton Ny | 2,030 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Hannawa .
Boat launches
- Colton
- Grass River
- St Regis River
- Mcginnis Road 398, Saint Lawrence County
- Park Lane Waddington
- Lakeshore Drive Morrisburg
Campgrounds
- Higley Flow State Park
- Coles Creek State Park
- Iroquois Municipal Campground
- Riverside/Cedar - St. Lawrence
- Upper Canada Sanctuary - St. Lawrence
- Eel Weir State Park
More reservoirs
Track Hannawa 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 Hannawa
Where does the data for Hannawa 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 Hannawa .