Chessman Main Dam dam
Chessman Main Dam
Chessman Main Dam, located in Rimini, Montana, is a vital water supply structure owned by the local government and regulated by the Montana Department of Natural Resources and Conservation. Built in 1908, this earth dam stands at a height of 57 feet and stretches 440 feet in length, with a storage capacity of 2370 acre-feet on Beaver Creek. The dam serves the primary purpose of water supply, with a normal storage capacity of 1630 acre-feet and a maximum discharge of 30 cubic feet per second.
With a high hazard potential and satisfactory condition assessment, Chessman Main Dam underwent its last inspection in August 2020, emphasizing the importance of consistent monitoring and maintenance for public safety. The dam features a controlled spillway with a width of 105 feet, ensuring effective water management during peak flow periods. Despite its age, the dam remains structurally sound and meets regulatory requirements, showcasing the resilience of this multi-arch design in soil foundation.
In the midst of increasing climate variability, Chessman Main Dam stands as a crucial infrastructure for water resource management in Lewis and Clark County. Its location in a high-risk area highlights the need for proactive risk management measures to mitigate potential hazards and ensure the continued safe operation of this essential water supply structure.
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 Chessman Main Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Tenmile Creek Near Rimini Mt | 31 cfs | → |
| Tenmile Creek Near Helena Mt | 42 cfs | → |
| Prickly Pear Creek Near Clancy Mt | 40 cfs | → |
| Boulder River Near Boulder Mt | 311 cfs | → |
| Missouri River Bl Hauser Lake Nr Helena Mt | 3,320 cfs | → |
| Clark Fork At Deer Lodge Mt | 176 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Chessman Main Dam.
Boat launches
- Helena Regulating Reservoir Road Lewis And Clark County
- Smith Road Helena Valley Northeast
- Cross Drive Helena Valley Northeast
- York Road Lewis And Clark County
- Hauser Dam Road Helena Valley Northeast
- White Sandy Boat Ramp
Campgrounds
- Park Lake Campground
- Park Lake
- Moose Creek Cabin
- Cromwell Dixon Campground
- Cromwell Dixon
- Fort Harrison Rv Military - National Guard
Fishing spots
Track Chessman Main Dam 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 Chessman Main Dam
Where does the data for Chessman Main Dam 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 High 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 Chessman Main Dam.