Lewis dam
Lewis
Lewis is a privately owned earth dam located in Big Horn, Wyoming, along Gypsum Creek offstream. Built in 1948 for irrigation purposes, the dam stands at 19 feet high and spans 1540 feet in length. With a storage capacity of 122 acre-feet, Lewis has a spillway width of 40 feet and an uncontrolled spillway type.
Despite its low hazard potential, Lewis is currently in poor condition as of the last inspection in May 2017. The dam is regulated by the Wyoming State Engineer's Office and undergoes regular inspections, with an inspection frequency of 5 years. While the risk assessment for Lewis indicates a moderate level of risk, there are no specific risk management measures or emergency action plans in place.
As a vital water resource structure in the region, Lewis serves as a reminder of the importance of maintaining and monitoring dams for the safety of surrounding communities and the sustainability of water resources in the face of changing climate conditions.
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 Lewis -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Shoshone River Near Lovell | 383 cfs | → |
| Bighorn River At Kane | 1,230 cfs | → |
| Clarks Fork Yellowstone River Nr Belfry Mt | 1,950 cfs | → |
| Bighorn River Near St. Xavier | 1,610 cfs | → |
| Clarks Fork Yellowstone River At Edgar Mt | 1,910 cfs | → |
| Little Bighorn River At State Line Nr Wyola Mt | 169 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Lewis.
Boat launches
Campgrounds
- Horseshoe Bend - Bighorn Canyon National Rec Area
- Full Hook-Up Campsite
- Lovell Camper Park
- Trail Creek Canyon Campground
- Trail Creek/Barry's Landing Campground
- Barrys Landing - Bighorn Canyon National Rec Area
Fishing spots
Paddle runs
- Gypsum Creek
- Crooked Creek
- Forest Boundary, Sec. 35, T8s, R27e To Headwaters, Sec. 32, T7s, R27e
- Bear Creek
More reservoirs
Track Lewis 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 Lewis
Where does the data for Lewis 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 Lewis.