South Nelson 1 dam
South Nelson 1
South Nelson 1, located in Alma, Wisconsin, is a flood risk reduction structure built in 1966 by the USDA NRCS. This earth dam on Spring Creek stands at a height of 40 feet and has a hydraulic height of 30 feet, with a storage capacity of 172 acre-feet. With a length of 600 feet and a surface area of 8 acres, this dam plays a crucial role in controlling debris and mitigating flood risks in the area.
Managed by the Wisconsin Department of Natural Resources, South Nelson 1 is regularly inspected and maintained to ensure its structural integrity and functionality. The dam has an uncontrolled spillway with a width of 84 feet, allowing for a maximum discharge of 3191 cubic feet per second. Despite its low hazard potential, the dam is classified as having a moderate risk level due to its location and potential impact in the event of a breach.
South Nelson 1 serves as a vital water resource infrastructure in Buffalo County, Wisconsin, providing protection to the surrounding community from flood events and ensuring the safety and sustainability of the area. Climate and water resource enthusiasts will appreciate the design and purpose of this dam, as well as its contribution to the overall water management efforts in the region.
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 South Nelson 1 -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Zumbro River At Kellogg | 1,550 cfs | → |
| Chippewa River At Durand | 7,010 cfs | → |
| Trempealeau River At Arcadia | 657 cfs | → |
| Trempealeau River At Dodge | 793 cfs | → |
| Mississippi River At Winona | 29,300 cfs | → |
| Mississippi River At Red Wing | 18,800 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near South Nelson 1.
Boat launches
- Mississippi River -- Alma Marina
- Mississippi River -- Beef Slough Landing
- Mississippi River -- Indian Slough Landing
- Mississippi River -- Dairyland Power Landing (Alma)
- Beef Slough/Fox Coulee -- Access
- Chippewa River -- Access
Campgrounds
- Reicks Lake Park
- Reicks Lake Park Campground
- Richard J. Dorer State Forest- Kruger Campground
- Richard J. Dorer Sf -Snake Creek
- Richard J. Dorer Sf -Zumbro Bottom Horse Camp North
- Richard J. Dorer Sf -Zumbro Bottom Horse Camp West
Fishing spots
Track South Nelson 1 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 South Nelson 1
Where does the data for South Nelson 1 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 South Nelson 1.