Lake Denmark dam
Lake Denmark
Lake Denmark in Dover, New Jersey, is a Federal-owned water supply reservoir completed in 1904 by the US Army for multiple purposes such as fire protection, stock, fish and wildlife pond, flood risk reduction, recreation, and water supply. The dam is primarily an earth structure with a height of 12 feet and a hydraulic height of 9 feet, serving a drainage area of 5 square miles with a maximum discharge capacity of 402 cubic feet per second. With a normal storage capacity of 2257 acre-feet and a maximum storage of 3203 acre-feet, the reservoir covers a surface area of 299 acres and holds a significant amount of water for various uses.
Managed and regulated by the US Army, Lake Denmark has a high hazard potential and undergoes inspections every 4 years to ensure its structural integrity. The reservoir features an uncontrolled spillway with a width of 30 feet and outlet gates including a slide (sluice gate) and two valves. Although the condition assessment is not available, the risk assessment is moderate, and there are measures in place for risk management. While the dam does not have a Emergency Action Plan (EAP) prepared, it meets regulatory guidelines and has emergency contacts updated periodically.
Despite its age, Lake Denmark continues to play a crucial role in water resource management and climate resilience in the region, providing essential services for the community while maintaining a balance between water supply, recreation, and environmental conservation. As a key infrastructure asset in Morris County, New Jersey, the reservoir underscores the importance of proactive monitoring, risk assessment, and emergency preparedness in safeguarding water resources and mitigating potential hazards associated with dam operations.
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 Lake Denmark -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Green Pond Brook At Picatinny Arsenal Nj | 2 cfs | → |
| Green Pd Bk Bl Picatinny Lk At Picatinny Ars Nj | 2 cfs | → |
| Rockaway River Above Reservoir At Boonton Nj | 472 cfs | → |
| Pequannock R At Macopin Intake Dam Nj | 14 cfs | → |
| Musconetcong River At Outlet Of Lake Hopatcong Nj | 14 cfs | → |
| Rockaway River Below Reservoir At Boonton Nj | 9 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Lake Denmark .
Boat launches
- Dell Avenue 9, Netcong
- Jefferson Lake Road Sussex County
- North Corporate Drive 2, Riverdale
- Lakeside Avenue Pompton Lakes
- Island Avenue Little Falls
- Greenwood Lake Turnpike Ringwood
Track Lake Denmark 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 Lake Denmark
Where does the data for Lake Denmark 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 Lake Denmark .