Johnsonville dam
Johnsonville
Johnsonville is a private hydroelectric dam located in Rensselaer, New York, along the Hoosic River. Constructed in 1909, this concrete gravity dam stands at 39 feet high and spans 529 feet in length, with a storage capacity of 6430 acre-feet. The dam has a spillway width of 526 feet and can discharge up to 11000 cubic feet per second, making it a crucial infrastructure for water resource management in the area.
Managed by the Federal Energy Regulatory Commission, Johnsonville has a high hazard potential due to its size and location. The dam is inspected regularly by the same agency to ensure its safety and functionality. Despite its age, Johnsonville remains a significant player in the local water resource system, contributing to both hydroelectric power generation and water storage for the surrounding area. As climate change continues to impact water resources, the proper maintenance and monitoring of dams like Johnsonville are essential for sustainable water management practices.
With its historical significance and role in modern water resource management, Johnsonville serves as a reminder of the importance of hydroelectric infrastructure in the face of changing climate conditions. As the dam continues to play a vital role in the region's water management strategies, it stands as a testament to the enduring impact of human engineering on the natural environment. For water resource and climate enthusiasts, Johnsonville offers a fascinating case study in the intersection of technology, sustainability, and environmental stewardship.
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 Johnsonville -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Hoosic River Near Eagle Bridge Ny | 1,090 cfs | → |
| Hudson R Above Lock 1 Nr Waterford Ny | 10,100 cfs | → |
| Hudson River At Lock 1 Near Waterford Ny | 8,410 cfs | → |
| Walloomsac River Near North Bennington | 216 cfs | → |
| Mohawk River At Cohoes Ny | 5,910 cfs | → |
| Batten Kill Below Mill At Battenville Ny | 1,110 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Johnsonville .
Boat launches
- Hudson River Road 951, City Of Mechanicville
- Lock One Road Town Of Halfmoon
- 123rd Street 6, City Of Troy
- Flightlock Road Town Of Waterford
- Schuyler Island Way Schuylerville
- Crescent Road Town Of Colonie
Campgrounds
- Lake Lauderdale Campground
- Cherry Plain State Park
- Cherry Plain State Park Campgrounds
- Camping On The Battenkill
- Sherman Brook Campsite
- Moreau Lake State Park
Track Johnsonville 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 Johnsonville
Where does the data for Johnsonville 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 Johnsonville .