Lower Millpond Dam dam
Lower Millpond Dam
Lower Millpond Dam, located in Old Lyme, Connecticut, is a masonry structure with a height of 14 feet and a length of 160 feet. This dam serves a primary purpose of recreation, providing a storage capacity of 45 acre-feet and covering a surface area of 6 acres. It is regulated by the Connecticut Department of Energy and Environmental Protection (DEEP) and is subject to state permitting, inspection, and enforcement.
The dam, situated on Mill Brook, poses a significant hazard potential with a moderate risk assessment rating. Despite this, the condition assessment conducted in October 2019 deemed the dam to be satisfactory. The dam has an uncontrolled spillway with a width of 40 feet, and it has not been modified in recent years. The last inspection date was in October 2019, with a scheduled inspection frequency of every 5 years.
For water resource and climate enthusiasts, Lower Millpond Dam provides an interesting case study in dam management and risk assessment. With its recreational purpose and state-regulated status, the dam serves as a vital infrastructure for the community while also presenting potential risks that need to be carefully monitored and managed. Its location in the scenic area of Old Lyme adds to the significance of its role in water resource management and climate resilience efforts in the region.
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 Lower Millpond Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| East Branch Eightmile River Near North Lyme | 34 cfs | → |
| Eightmile R At North Plain | 25 cfs | → |
| Indian River Near Clinton | 6 cfs | → |
| Salmon River Near East Hampton | 130 cfs | → |
| Yantic River At Yantic | 146 cfs | → |
| Connecticut R At Middle Haddam | 47,100 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Lower Millpond Dam.
Boat launches
- Shore Road Old Lyme
- Rogers Lake Public Boat Ramp
- Main Street Essex
- Great Island
- Four Mile River
- Powers Lake
Campgrounds
Fishing spots
Paddle runs
- Begins Below The Tailrace Of The Rainbow Dam To The Confluence With The Connecticut River
- 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
- New Hartford/Canton Town Line To The Confluence With The Nepaug River
- The Confluence Of The East And West Branches To The Confluence With The Farmington River In East Granby
- The Hartland Headwaters To The Confluence With The Salmon Brook Main Stem
Track Lower Millpond 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 Lower Millpond Dam
Where does the data for Lower Millpond 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 Lower Millpond Dam.