Jawbone Dam #1 dam
Jawbone Dam #1
Jawbone Dam #1, located in Harlowton, Montana, was completed in 1966 by the USDA NRCS for the purpose of flood risk reduction along Jawbone Creek. This earth dam stands at a height of 31 feet and a structural height of 35 feet, with a length of 650 feet and a drainage area of 1.97 square miles. The dam has a spillway width of 20 feet and an uncontrolled spillway type, with a maximum discharge capacity of 140 cubic feet per second.
With a hazard potential rated as high and a risk assessment of moderate, Jawbone Dam #1 has undergone satisfactory condition assessments and inspections. The dam is owned and regulated by the local government, with state jurisdiction and permitting, inspection, and enforcement carried out by the DNRC. Emergency action plans have been prepared, although last updated in May 2020, to ensure the safety and protection of nearby residents and infrastructure in the event of a dam failure.
Water resource and climate enthusiasts interested in the engineering and management of dams will find Jawbone Dam #1 to be an intriguing case study. The dam's unique design, construction, and purpose, as well as its risk assessment and emergency preparedness, offer valuable insights into the challenges and considerations involved in safeguarding communities from the impacts of flooding. As a key flood risk reduction structure in Wheatland County, Montana, Jawbone Dam #1 plays a critical role in protecting lives and property along Jawbone Creek.
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 Jawbone Dam #1 -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Musselshell River At Harlowton Mt | 188 cfs | → |
| Musselshell River Nr Martinsdale | 175 cfs | → |
| Musselshell River Ab Mud Cr Nr Shawmut Mt | 90 cfs | → |
| South Fork Musselshell R Ab Martinsdale Mt | 43 cfs | → |
| Boulder River At Big Timber Mt | 1,370 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Jawbone Dam #1.
Campgrounds
- Chief Joseph City Park
- Jellison Place Campground
- Selkirk Fas
- Haymaker Dispersed Camping Area
- Jellison Place
- Martinsdale Reservoir Fas
Fishing spots
- Big Elk Creek
- Deadmans Basin Reservoir
- East Fork Cottonwood Creek
- Flagstaff Reservoir
- Ackley Lake Feeder Canal
- Bair Reservoir
Paddle runs
Track Jawbone Dam #1 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 Jawbone Dam #1
Where does the data for Jawbone Dam #1 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 Jawbone Dam #1.