Thiellis dam
Thiellis
Thiellis, also known as Big Pond, is a privately owned earth dam located in Joliet, Montana. Built in 1972 by the USDA NRCS, this dam primarily serves the purpose of irrigation, with a storage capacity of 76 acre-feet and a surface area of 8 acres. The dam stands at a height of 18 feet and stretches out to a length of 610 feet, holding back Thiel Creek and regulating its flow.
Managed by the Montana Department of Natural Resources Conservation (DNRC), Thiellis is subject to state regulations, permitting, inspection, and enforcement to ensure its safety and functionality. Despite being rated as having a low hazard potential and not yet assessed for condition, the dam plays a crucial role in supporting agricultural activities in the region. The surrounding area, situated in Carbon County, Montana, benefits from the water resources managed by Thiellis for irrigation purposes.
Water resource and climate enthusiasts would find Thiellis to be a fascinating example of human intervention in water management. With its modest size and purpose-driven design, this earth dam showcases the importance of sustainable water infrastructure in supporting agricultural activities and managing water resources effectively. As a part of the larger network of dams in Montana, Thiellis contributes to the overall water management efforts in the state, highlighting the intersection of human activity and environmental stewardship in ensuring water availability for future generations.
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 Thiellis -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Rock Creek Near Red Lodge Mt | 402 cfs | → |
| Willow Creek Near Boyd Mt | 5 cfs | → |
| Red Lodge Cr Ab Cooney Re Nr Boyd Mt | 15 cfs | → |
| West Rosebud Creek Near Roscoe Mt | 83 cfs | → |
| Stillwater River Near Absarokee Mt | 2,090 cfs | → |
| Clarks Fork Yellowstone River Nr Belfry Mt | 4,600 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Thiellis.
Boat launches
Campgrounds
- Basin Campground
- Tent Camp Site
- Sheridan Campground
- Jimmy Joe Campground
- Rattin Campground
- Rattine Campground
Fishing spots
Paddle runs
- Custer Boundary, Sec. 6, T8s, R20e To Absaroka-Beartooth Wilderness Boundary
- Custer Forest Boundary, Sec. 1, T7s, S16e To Absaroka-Beartooth Wilderness Boundary
- Custer Forest Boundary, Sec. 19, T8s, R20e To Absaroka-Beartooth Wilderness Boundary
- Absaroka-Beartooth Wilderness Boundary To Headwaters, Sec. 25, T8s, R17e
- Confluence Rock Creek, Sec. 34, T8s, R19e To Absaroka-Beartooth Wilderness Boundary
- Absaroka-Beartooth Wilderness Boundary To Headwaters, Sec. 10, T9s, R17e
Track Thiellis 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 Thiellis
Where does the data for Thiellis 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 Thiellis.