Jocko dam
Jocko
Jocko is a federal-owned dam located in Missoula, Montana, with a primary purpose of irrigation. Built in 1937 by the Bureau of Indian Affairs, Jocko Dam stands at a structural height of 93 feet and has a storage capacity of 8,869 acre-feet. The dam spans 310 feet along the Jocko River and is primarily constructed from earth materials, serving as a vital resource for water management in the region.
Despite its age, Jocko Dam remains a crucial infrastructure for water supply and recreational activities in the area. With a high hazard potential, the dam is subject to regular inspections by the Bureau of Indian Affairs to ensure its safety and functionality. The dam's controlled spillway and historical significance make it a key feature in the landscape of Arlee, Montana, offering both practical benefits and a glimpse into the region's water resource management history.
With its very high risk assessment rating, Jocko Dam underscores the importance of effective risk management and emergency preparedness. Although the condition assessment is currently listed as "Not Available," the Bureau of Indian Affairs continues to monitor and maintain the dam to mitigate potential hazards and ensure the safety of surrounding communities. As a key player in the irrigation infrastructure of the area, Jocko Dam's role in water resource management and climate resilience highlights the need for ongoing vigilance and proactive measures to safeguard this essential resource.
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 Jocko -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| South Fork Jocko River Near Arlee Mt | 191 cfs | → |
| Mission Cr Ab Reservoir Nr St Ignatius Mt | 68 cfs | → |
| Blackfoot River Near Bonner Mt | 3,240 cfs | → |
| South Crow Creek Near Ronan Mt | 9 cfs | → |
| Clark Fork Above Missoula Mt | 4,940 cfs | → |
| Clark Fork At Turah Bridge Nr Bonner Mt | 1,690 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Jocko.
Boat launches
- South Holland Lake Road 232, 59826 Montana
- Whitaker Boat Launch
- Whitaker Bridge Day Use
- Johnsrud Boat Launch
- Mt 200 10495, Missoula County
Campgrounds
- Hidden Lake Campground
- Lake Inez Campground
- Lake Inez
- Double Arrow Lookout
- Lakeside (Old Alva)
- Seeley Lake Campground
Fishing spots
Paddle runs
- Headwaters, Sec. 17, T19n, R15w To Seeley Lake, Sec. 20, T17n, R15w
- Wrangle Creek Headwaters, Sec. 18, T15n, R18w To Mainstem, Sec. 21, T15n, R18w
- Lake Creek Headwaters, Sec. 30, T15n, R18w To Mainstem, Sec. 21, T15n, R18w
- High Falls Creek Headwaters, Sec. 5, T14n, R18w To Mainstem, Sec. 2, T14n, R18w
- Morrell Falls, Sec. 24, T18n, R15w To Morrell Falls Trailhead, Sec. 36, T18n, R15w
- East Fork Headwaters, Sec. 8, T14n, R17w To Mainstem, Sec. 14, T14n, R18w
More reservoirs
Track Jocko 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 Jocko
Where does the data for Jocko 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 Jocko.