Nielson dam
Nielson
Nielson, also known as Arapahoe, is a privately owned dam located in Fremont, Wyoming, specifically in the city of East Thermopolis. Completed in 1934, this earth dam serves multiple purposes including fire protection, stock watering, small fish pond, and irrigation. It stands at a height of 15 feet with a hydraulic height of 10 feet and a length of 1250 feet, creating a storage capacity of 385 acre-feet.
Despite its low hazard potential, Nielson is rated as having poor condition as of the last inspection in July 2019. The dam has a spillway width of 30 feet and an uncontrolled spillway type. It is regulated by the State Engineer's Office and is subject to regular inspections, enforcement, and permitting by the state regulatory agency. While the risk assessment for Nielson is moderate, with a rating of 3, there are currently no inundation maps prepared or emergency action plan in place.
Water resource and climate enthusiasts should keep an eye on Nielson for any updates regarding its condition and risk management measures. With its strategic location on the W Fork Sheep Creek, this dam plays a crucial role in the local water supply and ecosystem. Continued monitoring and maintenance will be essential to ensure the safety and functionality of Nielson for the surrounding community and environment.
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 Nielson -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Cottonwood C At High Island Rnch Nr Hamilton Dome | 1 cfs | → |
| Wind River Near Kinnear | 330 cfs | → |
| Wind River Near Crowheart | 1,630 cfs | → |
| Bull Lake Creek Near Lenore | 831 cfs | → |
| Wind R Bl Boysen Res Wyo | 819 cfs | → |
| Fivemile Creek Near Shoshoni | 117 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Nielson.
Boat launches
- Brannon Road Fremont County
- Tough Creek Campground
- Us 26;Wy 789 Fremont County
- Lower East River Road Hot Springs County
Campgrounds
Fishing spots
Paddle runs
Track Nielson 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 Nielson
Where does the data for Nielson 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.