Chapman Dam dam
Chapman Dam
Chapman Dam, located in Nelson Corners, St. Lawrence County, New York, is a privately owned concrete dam completed in 1971 for recreational purposes. Standing at 16 feet high and 60 feet long, the dam holds a storage capacity of 1800 acre-feet and covers a surface area of 320 acres, making it a popular destination for outdoor enthusiasts and nature lovers. The dam is situated on Grass Creek and is regulated by the New York State Department of Environmental Conservation, ensuring proper inspection, permitting, and enforcement measures are in place to maintain its safety and functionality.
Despite its low hazard potential and moderate risk assessment rating, Chapman Dam has not been conditionally assessed or rated. The last inspection on record dates back to June 1994, highlighting the need for a more recent evaluation to ensure the dam's structural integrity and safety standards. With a maximum discharge capacity of 560 cubic feet per second and an uncontrolled spillway width of 20 feet, Chapman Dam plays a crucial role in water resource management and flood control in the region. As a significant feature in the local landscape, efforts to update its emergency action plan, risk management measures, and hazard assessment are essential for the continued sustainability of this vital water infrastructure.
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 Chapman Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| West Branch Oswegatchie R Nr Harrisville Ny | 776 cfs | → |
| Oswegatchie River Near Heuvelton Ny | 2,470 cfs | → |
| Black River At Watertown Ny | 4,710 cfs | → |
| Oswegatchie River Near Oswegatchie Ny | 947 cfs | → |
| Beaver River At Croghan Ny | 684 cfs | → |
| Raquette River At South Colton Ny | 961 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Chapman Dam.
Track Chapman Dam 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 Chapman Dam
Where does the data for Chapman Dam 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 Chapman Dam.