Holyoke - Overflow No. 4 dam
Holyoke - Overflow No. 4
Holyoke - Overflow No. 4, located in Holyoke, Massachusetts, is a vital structure owned by the local government and managed by the Federal Energy Regulatory Commission (FERC). Constructed in 1891, this masonry dam serves the primary purpose of hydroelectric power generation while also providing recreational opportunities. With a height of 22.5 feet and a storage capacity of 26,000 acre-feet, this dam plays a crucial role in the region's water resource management.
The dam is situated on the Holyoke Canal, within the Hampden County of Massachusetts, and has a controlled spillway width of 150 feet. It has a low hazard potential and a very high risk assessment rating, making it essential to ensure proper maintenance and risk management measures. With four slide (sluice gate) outlet gates and a maximum discharge capacity of 950 cubic feet per second, Holyoke - Overflow No. 4 is a significant infrastructure contributing to the area's water supply and energy needs.
Despite not being state-regulated, the dam undergoes regular inspections by FERC, with the last inspection conducted in September 2017. The structure has a rich history of serving the community for over a century and continues to be a key component in the water resource infrastructure of the region. As a notable example of early hydroelectric development in the area, Holyoke - Overflow No. 4 stands as a reminder of the intersection between water resources, climate, and sustainable energy practices.
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 Holyoke - Overflow No. 4 -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Connecticut R At Interstate 391 Bridge At Holyoke | 24,800 cfs | → |
| Chicopee River At Indian Orchard | 1,030 cfs | → |
| Westfield River Near Westfield | 388 cfs | → |
| Mill River At Northampton | 41 cfs | → |
| Connecticut River At Thompsonville | 26,800 cfs | → |
| Middle B Westfield River At Goss Heights | 8 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Holyoke - Overflow No. 4 .
Boat launches
- Old Apremont Way, Westfield
- Water Street 266-334, Springfield
- West Street 121, Springfield
- Mount Tom Road 900-978, Easthampton
- South End Bridge Agawam
- Red Bridge Road 16, Wilbraham
Campgrounds
- Westover Arb Military
- Koa Weathampton
- Primitve Camping Area
- Chester - Blanford State Forest
- Dar State Forest
- Granville State Forest
Fishing spots
- Lake Washington Fishing Area
- Trout Hatchery
- Great Brook Reservoir
- Lower Fulton Park Pond
- Lake Quassapaug
Paddle runs
- The Massachusetts-Connecticut State Line In Hartland To The Confluence With The Salmon Brook Main Stem
- The Confluence Of The East And West Branches To The Confluence With The Farmington River In East Granby
- Begins Below The Tailrace Of The Rainbow Dam To The Confluence With The Connecticut River
- The Hartland Headwaters To The Confluence With The Salmon Brook Main Stem
- New Hartford/Canton Town Line To The Confluence With The Nepaug River
- The Confluence With The Nepaug River To A Point 0.2 Miles Below The Lower Collinsville Dam Tailrace
Track Holyoke - Overflow No. 4 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 Holyoke - Overflow No. 4
Where does the data for Holyoke - Overflow No. 4 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 Holyoke - Overflow No. 4 .