Macopin Reservoir Dam dam
Macopin Reservoir Dam
The Macopin Reservoir Dam, located in West Milford Township, New Jersey, is a stone dam completed in 1892 for the primary purpose of water supply. It stands at a height of 34 feet and has a length of 434 feet, with a storage capacity of 206 acre-feet and a drainage area of 63.7 square miles. The dam, built on the Pequannock River, is owned by the local government and regulated by the New Jersey Department of Environmental Protection, with state permitting and inspection in place.
Despite being designated as having a high hazard potential, the Macopin Reservoir Dam is currently assessed as satisfactory in condition, with the last inspection conducted in April 2021. The dam has a regular inspection frequency of every 2 years, and emergency action plans are in place, although their last revision was in December 2020. With a maximum discharge capacity of 17,600 cubic feet per second, the dam plays a crucial role in managing water resources in the region and ensuring the safety of surrounding communities in the event of emergencies.
Overall, the Macopin Reservoir Dam serves as a vital infrastructure for water supply in Morris County, New Jersey, with its historical significance dating back to the late 19th century. As a stone dam with a high hazard potential, it is subject to rigorous regulatory oversight and maintenance to ensure its continued functionality and safety. Climate enthusiasts and water resource experts can appreciate the dam's role in managing water resources and its importance in safeguarding the local environment and population from potential risks associated with its operation.
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 Macopin Reservoir Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Pequannock R At Macopin Intake Dam Nj | 6 cfs | → |
| Pequannock River At Riverdale Nj | 12 cfs | → |
| Wanaque R At Wanaque Nj | 13 cfs | → |
| West Brook Near Wanaque Nj | 6 cfs | → |
| Ramapo River At Pompton Lakes Nj | 67 cfs | → |
| Pompton River At Pompton Plains Nj | 126 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Macopin Reservoir Dam.
Boat launches
- North Corporate Drive 2, Riverdale
- Lakeside Avenue Pompton Lakes
- Greenwood Lake Turnpike Ringwood
- Ringwood-Ramapo Trail Ringwood
- Island Avenue Little Falls
- Blue Lake Road Town Of Warwick
Track Macopin 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.
About Macopin Reservoir Dam
Where does the data for Macopin 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.
Other water bodies near here
Snoflo-tracked reservoirs and dams within driving distance of Macopin Reservoir Dam.