Nilan East Dam dam
Nilan East Dam
Nilan East Dam, located in Augusta, Montana, stands as a crucial structure for irrigation purposes along TR-Elk Creek. Built in 1951, this earth dam reaches a height of 51 feet and spans 1010 feet in length, with a storage capacity of 15,600 acre-feet. The dam's spillway, measuring 72 feet wide, operates as uncontrolled. Despite its high hazard potential, the dam has been assessed as satisfactory in condition, with the last inspection conducted in October 2021.
Situated within Lewis and Clark County, Nilan East Dam plays a vital role in water resource management, holding a normal storage capacity of 10,092 acre-feet and serving as a lifeline for agricultural activities in the region. Administered by the State of Montana and regulated by the Department of Natural Resources and Conservation (DNRC), the dam undergoes regular inspections, enforcement, and permitting processes to ensure public safety and compliance with state regulations. With a moderate risk rating of 3, the dam is monitored closely for any potential issues or emergencies.
Congressional District 00 in Montana, represented by Greg Gianforte (R), oversees Nilan East Dam's operations and maintenance. The dam's location at S20 20N 7W, with a drainage area of 3.55 square miles, underscores its strategic significance in water storage and distribution. As a focal point for water resource and climate enthusiasts, Nilan East Dam serves as a testimony to sustainable water management practices and the critical role of infrastructure in supporting agricultural livelihoods and environmental sustainability in the region.
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 Nilan East Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Sun River Bl Willow Cr Nr Augusta Mt | 588 cfs | → |
| Sun River Bl Diversion Dam Nr Augusta Mt | 988 cfs | → |
| South Fork Sun River Near Augusta Mt | 962 cfs | → |
| North Fork Sun River Near Augusta Mt | 729 cfs | → |
| Dearborn River Near Craig Mt | 150 cfs | → |
| Sun River At Simms Mt | 472 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Nilan East Dam.
Boat launches
Campgrounds
- Nilan Reservoir Fas
- Willow Creek Fas
- Double Falls Campground
- Bean Lake Fas
- Wood Lake
- Wood Lake Campground
Fishing spots
Paddle runs
- Headwaters, Sec. 13, T18n, R10w To Forest Boundary, Sec. 6, T17n, R7w
- Headwaters, Sec. 15, T18n, R10w To Straight Creek, Sec. 25, T19n, R10w
- Wilderness Boundary To South Fork Sun River, Sec. 26, T22n, R10w
- Headwaters, Sec. 4, T18n, R10w To North Fork Sun River, Sec. 26, T22n, R10w
- Dobrota Headwaters, Sec. 23, T18n, R10w To Mainstem, Sec. 31, T18n, R9w
- Fool Creek, Sec. 24, T25n, R11w To Wilderness Boundary
Track Nilan East 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 Nilan East Dam
Where does the data for Nilan East 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 Nilan East Dam.