Mill Dam dam
Mill Dam
Mill Dam, located in Madrid, New York, is a concrete structure built in 1916 on the Grass River. Owned and regulated by the local government, this dam has a height of 12 feet and a length of 396 feet, providing a storage capacity of 291 acre-feet. With a normal storage capacity of 140 acre-feet and a drainage area of 587 square miles, the dam plays a crucial role in water resource management in the region.
Despite being classified as low hazard potential, the dam at Mill Dam is considered to have a high risk due to its condition assessment not being rated. The last inspection of the dam was conducted in July 2009, highlighting the importance of regular monitoring and maintenance to ensure the safety and efficiency of the structure. With a spillway width of 364 feet and a maximum discharge capacity of 7200 cubic feet per second, Mill Dam is a significant component of the local water infrastructure, requiring ongoing risk management measures to mitigate potential hazards.
As water resource and climate enthusiasts, understanding the critical role that Mill Dam plays in the management of the Grass River watershed is essential. With its historical significance dating back over a century, this concrete structure serves as a key element in regulating water flow, providing storage capacity, and contributing to flood control efforts in the region. As efforts continue to assess and address the risks associated with the dam, it remains a focal point for sustainable water resource management and climate resilience initiatives in St. Lawrence County, New York.
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 Mill Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Grass River At Chase Mills Ny | 992 cfs | → |
| Raquette River At Raymondville Ny | 2,050 cfs | → |
| Oswegatchie River Near Heuvelton Ny | 2,030 cfs | → |
| St. Regis River At Brasher Center Ny | 1,150 cfs | → |
| Raquette River At South Colton Ny | 1,050 cfs | → |
| W Br St. Regis R Nr Parishville Ny | 362 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Mill Dam.
Boat launches
- Park Lane Waddington
- Mcginnis Road 398, Saint Lawrence County
- Grass River
- Lakeshore Drive Morrisburg
- Carman Road 5948, Iroquois
- Dundas Street Cardinal
Campgrounds
- Coles Creek State Park
- Iroquois Municipal Campground
- Riverside/Cedar - St. Lawrence
- Upper Canada Sanctuary - St. Lawrence
- Farran Park - St. Lawrence
- Mclaren Campsite - St. Lawrence
More reservoirs
Track Mill 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 Mill Dam
Where does the data for Mill 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 Mill Dam.