Lower Lake Nemahbin dam
Lower Lake Nemahbin
Lower Lake Nemahbin, located in Waukesha, Wisconsin, is a charming reservoir primarily owned and regulated by the local government for recreational purposes. Constructed in 1934, this Gravity-type dam stands at 8 feet tall and spans 200 feet in length, with a storage capacity of 1880 acre-feet. The dam serves as a beloved spot for water enthusiasts, offering a surface area of 268 acres and a maximum discharge capacity of 1050 cubic feet per second.
Despite being classified as having a low hazard potential and fair condition assessment, Lower Lake Nemahbin also poses a moderate risk level, as assessed in 2020. The dam is inspected every 10 years, with the last assessment conducted in August 2009. While the risk is deemed manageable, enthusiasts and stakeholders are urged to stay informed on the latest updates and safety measures, especially in the face of changing climate patterns that may impact water resources and infrastructure in the future. As a vital part of the local landscape, Lower Lake Nemahbin continues to provide a picturesque setting for outdoor activities and serves as a reminder of the importance of preserving and managing water resources in a sustainable manner.
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 Lower Lake Nemahbin -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Bark River At Nagawicka Road At Delafield | 41 cfs | → |
| Fox River At Waukesha | 98 cfs | → |
| Bark River Near Rome | 116 cfs | → |
| Mukwonago River At Mukwonago | 45 cfs | → |
| Rock River At Watertown | 1,050 cfs | → |
| Menomonee River At Menomonee Falls | 8 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Lower Lake Nemahbin.
Boat launches
- Lower Nemahbin Lake -- Boat Landing
- Upper Nemahbin Lake -- Boat Landing Next To I94
- Lower Nemahbin Lake -- Access
- Waukesha Co. Bark River At Genesee Lake Road
- Upper Genesee Lake -- Access
- Lower Nashotah Lake -- Boat Landing Next To Pabst Rd.
Campgrounds
- Naga-Waukee County Park Campground
- Pinewoods Campground
- Ottawa Lake Campground
- Harnischefeger Park
- Kmsf-Su Shelter 2
- Mukwonago County Park Campground
Fishing spots
Track Lower Lake Nemahbin 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 Lower Lake Nemahbin
Where does the data for Lower Lake Nemahbin 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 Low 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 Lower Lake Nemahbin.