D.F. Riley Grist Mill Dam Dam
D.F. Riley Grist Mill Dam
The D.F. Riley Grist Mill Dam, located in Hatfield, Massachusetts, is a historic masonry dam constructed in 1881 along the Mill River. This dam serves a primary purpose of recreation, providing a serene backdrop for outdoor enthusiasts and water resource aficionados alike. With a height of 19 feet and a hydraulic height of 14 feet, the dam holds a storage capacity of 580 acre-feet and covers a surface area of 0.05 square miles.
Despite its historical significance and recreational value, the D.F. Riley Grist Mill Dam is classified as having a significant hazard potential and a poor condition assessment. It is regulated by the Department of Conservation and Recreation in Massachusetts, with state jurisdiction and permitting in place. The dam's inspection frequency is every 5 years, with the most recent assessment in May 2018 revealing the need for maintenance and potential risk management measures.
Climate and water resource enthusiasts are drawn to the D.F. Riley Grist Mill Dam not only for its historical charm but also for the conservation efforts required to maintain its integrity. With a moderate risk assessment rating and a need for improvements in condition, this dam represents a focal point for balancing the preservation of natural resources with the safety and recreational opportunities it provides to the local community and visitors.
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 D.F. Riley Grist Mill Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Mill River At Northampton | 9 cfs | → |
| Deerfield River Near West Deerfield | 1,050 cfs | → |
| Connecticut R At Interstate 391 Bridge At Holyoke | 4,010 cfs | → |
| South River Near Conway | 8 cfs | → |
| West Branch Swift River Near Shutesbury | 2 cfs | → |
| Westfield River At Knightville | 49 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near D.F. Riley Grist Mill Dam.
Boat launches
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Campgrounds
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Fishing spots
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River runs
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About D.F. Riley Grist Mill Dam
Where does the data for D.F. Riley Grist 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 Significant 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 below 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.
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.