Deep Hollow Reservoir Dam
Deep Hollow Reservoir Dam
Deep Hollow Reservoir Dam, also known as Wilcox Reservoir, is a historic masonry dam located in Chester, Connecticut. Built in 1854, this dam serves as a crucial water supply source for the region, with a storage capacity of 255 acre-feet and a normal storage level of 200 acre-feet. The dam stands at a height of 28 feet and spans 352 feet, creating a surface area of 27.5 acres and draining a 4.07 square mile watershed.
Managed by the Connecticut Department of Energy and Environmental Protection (DEEP), Deep Hollow Reservoir Dam is considered to have a significant hazard potential but has been deemed to be in satisfactory condition as of the last assessment in October 2019. The dam has a spillway width of 88 feet and a maximum discharge capacity of 509 cubic feet per second. With regular inspections and adherence to state regulations, the dam continues to play a vital role in water resource management and climate resilience efforts in the area.
Deep Hollow Reservoir Dam's rich history, combined with its continued functionality as a water supply structure, makes it a site of interest for water resource and climate enthusiasts. As a key component of the region's infrastructure, this masonry dam stands as a testament to the importance of sustainable water management practices and the critical role dams play in supporting communities and ecosystems in the face of changing climate conditions.
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 Deep Hollow Reservoir Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| East Branch Eightmile River Near North Lyme | 46 cfs | → |
| Indian River Near Clinton | 5 cfs | → |
| Eightmile R At North Plain | 33 cfs | → |
| Connecticut R At Middle Haddam | 24,700 cfs | → |
| Salmon River Near East Hampton | 59 cfs | → |
| Coginchaug River At Middlefield | 29 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Deep Hollow Reservoir 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 Deep Hollow Reservoir Dam
Where does the data for Deep Hollow Reservoir 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.
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