Mianus Filter Plant Dam dam
Mianus Filter Plant Dam
The Mianus Filter Plant Dam, also known as Mianus Mill Pond, is a historic masonry dam located on the Mianus River in North Mianus, Greenwich, Connecticut. Built in 1875, the dam serves as a vital water supply structure for the area, with a storage capacity of 118 acre-feet and a normal storage level of 101 acre-feet. The dam has a height of 31 feet and a length of 130 feet, with a spillway width of 65 feet for uncontrolled overflow.
Managed by the Connecticut Department of Energy and Environmental Protection (DEEP), the Mianus Filter Plant Dam is state-regulated and undergoes regular inspections to ensure its structural integrity. The dam has a high hazard potential but is currently assessed as being in fair condition, with a moderate risk level. Despite its age, the dam continues to play a crucial role in providing water to the surrounding community and mitigating flood risks along the Mianus River.
With its picturesque location and rich history, the Mianus Filter Plant Dam is not only a functional infrastructure but also a significant cultural landmark in Fairfield County, Connecticut. Its association with the Mianus River and its role in water resource management make it a compelling site for water resource and climate enthusiasts to explore and appreciate the intersection of human engineering and natural processes in maintaining a sustainable water supply for 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 Mianus Filter Plant 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 | → |
| Saugatuck R Nr Westport | 18 cfs | → |
| Cross River Near Cross River Ny | 8 cfs | → |
| Cross River At Katonah Ny | 12 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Mianus Filter Plant Dam.
Boat launches
- Seagate Road 3, Greenwich
- Maple Way 10, Town Of North Castle
- Saugatuck River
- Roosevelt Road Westport
- Lloyd Harbor Road 72, Lloyd Harbor
- Hillspoint Road Westport
Campgrounds
- Ward Pound Ridge Reservation
- Mountain Lakes Park
- Croton Point Park
- Youth Camp Ii
- Youth Camp Iii
- Youth Camp I
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 Filter Plant 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 Filter Plant Dam
Where does the data for Mianus Filter Plant 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.
Other water bodies near here
Snoflo-tracked reservoirs and dams within driving distance of Mianus Filter Plant Dam.