Green Swamp #4 Dam dam
Green Swamp #4 Dam
Green Swamp #4 Dam, located in Passaic, New Jersey, is a concrete structure completed in 1925 primarily used for water supply purposes. Standing at a height of 65 feet and spanning 300 feet in length, this dam plays a crucial role in storing and regulating water from the Wanaque River. With a normal storage capacity of 81,730 acre-feet and covering a surface area of 2,310 acres, it serves as a vital resource for the region, ensuring a reliable water supply for various uses.
Managed by the New Jersey Department of Environmental Protection (NJDEP), Green Swamp #4 Dam is subject to state regulations, inspections, and enforcement to maintain its structural integrity and safety standards. Despite its high hazard potential, the dam's condition assessment in October 2021 reported it to be satisfactory. Regular inspections are conducted every two years to monitor its performance and address any potential risks or issues promptly. Additionally, emergency action plans are in place to ensure preparedness in case of any unforeseen events or emergencies.
With its strategic location in Wanaque Borough and its critical role in water management, Green Swamp #4 Dam stands as a testament to the importance of sustainable water resource management and climate resilience. As climate change continues to impact water systems and availability, structures like this dam play a vital role in ensuring a stable and secure water supply for the community while mitigating potential risks and hazards associated with extreme weather events.
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 Green Swamp #4 Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Wanaque R At Wanaque Nj | 14 cfs | → |
| West Brook Near Wanaque Nj | 7 cfs | → |
| Pequannock River At Riverdale Nj | 29 cfs | → |
| Ramapo River At Pompton Lakes Nj | 122 cfs | → |
| Pequannock R At Macopin Intake Dam Nj | 14 cfs | → |
| Pompton River At Pompton Plains Nj | 145 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Green Swamp #4 Dam.
Boat launches
- Lakeside Avenue Pompton Lakes
- North Corporate Drive 2, Riverdale
- Greenwood Lake Turnpike Ringwood
- Ringwood-Ramapo Trail Ringwood
- Blue Lake Road Town Of Warwick
- Laurel Meadow Drive Town Of Warwick
Track Green Swamp #4 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 Green Swamp #4 Dam
Where does the data for Green Swamp #4 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 Green Swamp #4 Dam.