Herrin Lake dam
Herrin Lake
Herrin Lake, located in Lewis and Clark County, Montana, is a state-regulated water resource with a primary purpose of serving as a fire protection, stock, or small fish pond. The dam, completed in 1949, is of earth type and stands at a height of 15 feet, with a storage capacity of 69 acre-feet. Despite its low hazard potential, the condition of Herrin Lake has not been rated, and there is no recent inspection data available.
This picturesque lake, situated in the Cottonwood area and fed by TR-WILLOW CREEK, provides essential water storage for the region, with a normal storage capacity of 36 acre-feet. While the dam has not been modified in recent years, it continues to play a vital role in maintaining water resources and supporting local ecosystems. As a water resource and climate enthusiast, Herrin Lake offers an opportunity to explore the intersection of human infrastructure and natural ecosystems in a stunning Montana setting.
With its serene waters and important role in fire protection and wildlife support, Herrin Lake is a valuable asset to the community. Managed by the Montana Department of Natural Resources and Conservation (DNRC), this dam exemplifies responsible water resource management in the region. As a visitor or researcher interested in water resources and climate, Herrin Lake offers a unique opportunity to study the impact of human intervention on natural water systems and the importance of sustainable practices 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 Herrin Lake -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Nevada Cr Ab Reservoir | 27 cfs | → |
| Blackfoot R Ab Nevada Cr Nr Helmville Mt | 765 cfs | → |
| Nf Blackfoot R Ab Dry Gulch Nr Ovando Mt | 824 cfs | → |
| Clark Fork At Goldcreek Mt | 380 cfs | → |
| Little Blackfoot River Near Garrison Mt | 153 cfs | → |
| Little Prickly Pear Cr At Wolf Cr Mt | 66 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Herrin Lake.
Campgrounds
- Hooper Park
- Moose Creek Campground (Free)
- Aspen Grove Campground
- Aspen Grove Group Use Campground
- Copper Creek
- Big Nelson Complex
Fishing spots
- Arrastra Creek
- Alice Creek
- River Junction Fishing Access
- Little Prickly Pear Creek
- Silver Creek
- Rattlesnake Creek
Paddle runs
More reservoirs
Track Herrin Lake 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 Herrin Lake
Where does the data for Herrin Lake 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 Herrin Lake.