Mianus River Dam dam
Mianus River Dam
The Mianus River Dam, also known as Mianus Pond, is a concrete structure located in Greenwich, Connecticut, that was completed in 1920. The dam's primary purpose is for recreation, with a storage capacity of 525 acre-feet and a surface area of 48 acres. Situated on the Mianus River, the dam is owned by the local government and is regulated by the Connecticut Department of Energy and Environmental Protection (DEEP).
With a significant hazard potential, the Mianus River Dam has a satisfactory condition assessment as of 2016, with inspection frequency every 5 years. The dam's spillway width is 250 feet, and it has a maximum discharge capacity of 10,158 cubic feet per second. The dam is designed as a multi-arch structure on a rock foundation and stands at a height of 20 feet with a length of 350 feet. The surrounding area offers recreational opportunities for visitors to enjoy the picturesque Mianus Pond.
Overall, the Mianus River Dam serves as a vital structure for both water resource management and recreational purposes in the Greenwich area. Its historical significance, coupled with its role in providing storage and flood control along the Mianus River, makes it a noteworthy site for water resource and climate enthusiasts to explore and appreciate.
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 Mianus River Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Rippowam River At Stamford | 7 cfs | → |
| Fivemile River Near New Canaan | 0 cfs | → |
| Norwalk R At South Wilton | 10 cfs | → |
| Cold Spring Brook At Cold Spring Harbor Ny | 2 cfs | → |
| Saugatuck R Nr Westport | 18 cfs | → |
| Cross River Near Cross River Ny | 8 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Mianus River Dam.
Boat launches
- Seagate Road 3, Greenwich
- Maple Way 10, Town Of North Castle
- Lloyd Harbor Road 72, Lloyd Harbor
- Saugatuck River
- Roosevelt Road Westport
- Hillspoint Road Westport
Campgrounds
- Ward Pound Ridge Reservation
- Mountain Lakes Park
- Croton Point Park
- Battle Row
- Park Shore Day Camp
- Youth Camp Ii
Fishing spots
Paddle runs
- Kent Bridge To Boardman Bridge
- Pond Downstream Of Shepaug Reservoir Dam, Marked By Service Road Bridge To Ends In Backwaters Of Lake Lillinonah, Near Roxbury Falls
- Begins Downstream Of The Borough Of Bantam, At Stoddard Road Bridge To The Confluence With The Shepaug River
Track Mianus River 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 Mianus River Dam
Where does the data for Mianus River 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 Mianus River Dam.