Dam Report

Willimantic Reservoir Dam dam

Connecticut, USA Natchaug River Hazard High
Today high
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Tonight low
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Dam height
29ft
Hazard rating
High
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Willimantic Reservoir Dam -- None dam
Willimantic Reservoir Dam None · Natchaug River
About this dam

Willimantic Reservoir Dam

The Willimantic Reservoir Dam, located in Willimantic, Connecticut, is a key structure managed by the local government for water supply purposes. Constructed in 1885, this concrete dam stands at a height of 29 feet and has a length of 491.3 feet. The reservoir has a maximum storage capacity of 1670 acre-feet, with a normal storage level of 750 acre-feet, serving the surrounding area for water needs.

The dam, situated on the Natchaug River, is regulated by the Connecticut Department of Energy and Environmental Protection (DEEP) and undergoes regular inspections to ensure its safety and functionality. With a high hazard potential but deemed to be in satisfactory condition as of the last assessment in 2019, the Willimantic Reservoir Dam plays a critical role in water resource management in the region. Its location in Windham County, under the oversight of local authorities and state agencies, highlights the collaborative efforts to safeguard this vital infrastructure.

This historic dam not only provides crucial water storage but also contributes to flood control and water resource management in the area. With a spillway width of 280 feet and a maximum discharge capacity of 38,125 cubic feet per second, the Willimantic Reservoir Dam is a significant piece of infrastructure that ensures water security for the community while adhering to state regulatory standards. As climate change impacts water resources, the maintenance and oversight of structures like the Willimantic Reservoir Dam become increasingly important in ensuring resilience against changing environmental conditions.

StateNone
River / streamNatchaug River
NID IDCT00198
Owner typeLocal Government
Primary purposeWater Supply
Dam typeConcrete
Year built1885
Dam height29 ft
Dam length491 ft
Max storage1,670 AF
Normal storage750 AF
Surface area100.0 ac
Drainage area166.0 sq mi
Hazard potentialHigh
ConditionSatisfactory
Last inspectionTue, 08 Oct 2019 00:00:00 GMT

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.
Detailed forecast

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.

Hourly detail

Next 5 days, hour by hour

Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.

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Deep dive

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.

TimeConditionTemp (°F)Snow (in)Rain (in)Humidity (%)Wind (mps)Wind dir
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Long-term outlook

15-day temperature & precipitation

Daily temperatures, snow, and rain projected over the next two weeks.

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Regional inflow

Nearby streamflow gauges

USGS streamgauges around Willimantic Reservoir Dam -- inflows here typically show up in storage 24-72 hours later.

Track Willimantic Reservoir 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.

FAQ

About Willimantic Reservoir Dam

Where does the data for Willimantic 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 High 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.

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