Seymour Reservoir #3 Dam dam
Seymour Reservoir #3 Dam
Seymour Reservoir #3 Dam, located in Oxford, Connecticut, was completed in 1910 and serves as a critical water supply source for the region. With a dam height of 42 feet and a length of 730 feet, the dam has a maximum storage capacity of 245 acre-feet and a normal storage capacity of 206 acre-feet. The reservoir covers a surface area of 13 acres and has a drainage area of 0.7 square miles.
Managed by the Connecticut Department of Energy and Environmental Protection (DEEP), the dam is classified as a masonry structure and falls under state regulation for inspection, permitting, and enforcement. Despite being assessed as in fair condition during the last inspection in 2015, the dam is considered to have a significant hazard potential. The dam's spillway width is 24 feet, and it has a maximum discharge capacity of 280 cubic feet per second.
For water resource and climate enthusiasts, Seymour Reservoir #3 Dam represents a vital infrastructure piece that plays a crucial role in securing water supply for the surrounding communities. Its historical significance, combined with its structural features and state oversight, make it an essential component of the region's water management system. Understanding the dam's design, operations, and condition is key to ensuring the safety and sustainability of the water resources it supports.
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 Seymour Reservoir #3 Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Naugatuck River At Beacon Falls | 814 cfs | → |
| Housatonic River At Stevenson | 495 cfs | → |
| Pomperaug River At Southbury | 121 cfs | → |
| Mill R Nr Hamden | 54 cfs | → |
| Pootatuck R At Sandy Hook | 43 cfs | → |
| Weekeepeemee River At Hotchkissville | 33 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Seymour Reservoir #3 Dam.
Boat launches
- Lake Housatonic
- Lake Zoar
- Main Street Hamden
- Huntington Street Shelton
- Lake Lillinonah (Pond Brook)
- Sackett Point Road North Haven
Campgrounds
Fishing spots
- Reservoir Number 2
- Seymour Reservoir Number 2
- Seymour Reservoir Number 4
- Reservoir Number 1
- Seymour Reservoir Number 1
- Carrington Pond
Paddle runs
- Begins Downstream Of The Borough Of Bantam, At Stoddard Road Bridge To The Confluence With The Shepaug River
- Pond Downstream Of Shepaug Reservoir Dam, Marked By Service Road Bridge To Ends In Backwaters Of Lake Lillinonah, Near Roxbury Falls
- Begins Below The Tailrace Of The Lower Collinsville Dam To The Route 187 Bridge
- The Confluence With The Nepaug River To A Point 0.2 Miles Below The Lower Collinsville Dam Tailrace
- Kent Bridge To Boardman Bridge
- New Hartford/Canton Town Line To The Confluence With The Nepaug River
Track Seymour Reservoir #3 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 Seymour Reservoir #3 Dam
Where does the data for Seymour Reservoir #3 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 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 Seymour Reservoir #3 Dam.