Green Swamp #1 Dam dam
Green Swamp #1 Dam
Green Swamp #1 Dam, located in Bloomingdale Borough, Passaic, New Jersey, is a state-owned earth dam with a primary purpose of water supply. Completed in 1926, this dam stands at a height of 29 feet and spans a length of 640 feet, creating a reservoir with a normal storage capacity of 41,700 acre-feet and a surface area of 2,400 acres. It is regulated, permitted, inspected, and enforced by the New Jersey Department of Environmental Protection, ensuring its safe operation and maintenance.
The dam, situated on Post Brook, falls under the jurisdiction of the Philadelphia District of the US Army Corps of Engineers. Its hazard potential is classified as high, yet its condition assessment as of October 2021 was deemed satisfactory. With a biennial inspection frequency, the dam has a comprehensive Emergency Action Plan in place, last updated in February 2022. While there are no associated spillways or locks, Green Swamp #1 Dam remains a crucial infrastructure for water resource management in the region, highlighting the importance of ongoing monitoring and risk management measures.
Representing a vital component of New Jersey's water supply infrastructure, Green Swamp #1 Dam plays a key role in flood control and water storage for the surrounding area. As part of Congressional District 11, it is supported by Representative Mikie Sherrill and serves as a critical asset for ensuring water security and environmental protection. With its historical significance and ongoing regulatory oversight, the dam exemplifies the intersection of engineering, policy, and climate resilience in safeguarding water resources for future generations.
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 #1 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 #1 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 #1 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 #1 Dam
Where does the data for Green Swamp #1 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 #1 Dam.