Green Tank dam
Green Tank
Green Tank is a federal-owned earth dam located in Modoc, California, completed in 1975 for fire protection, stock, and small fish pond purposes. With a height of 8 feet and a length of 710 feet, this dam has a storage capacity of 480 acre-feet and serves a drainage area of 1.6 square miles. The dam features an uncontrolled spillway with a width of 30 feet and has a low hazard potential.
Managed by the Forest Service, Green Tank has not been inspected since August 2010, with a scheduled inspection frequency of 10 years. Despite its condition being rated as "Not Rated," the dam's risk assessment is moderate, indicating a level 3 risk. With no emergency action plan in place and limited risk management measures identified, the dam presents a potential need for further evaluation and preparation in the face of changing climate and water resource challenges.
For water resource and climate enthusiasts, Green Tank serves as a vital structure to monitor and assess in the context of evolving environmental conditions. With its primary purpose of fire protection and water storage, the dam's management and safety protocols will be crucial in ensuring its resilience to potential hazards. As climate impacts continue to unfold, the need for updated inspections, risk assessments, and emergency preparedness measures at Green Tank becomes increasingly imperative to safeguard both the dam's integrity and the surrounding ecosystem.
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 Green Tank -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Pit R Nr Canby Ca | 2 cfs | → |
| Sf Pit R Nr Likely Ca | 119 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Green Tank.
Boat launches
- Green Springs Boating Site
- Logan Slough Boating Site
- Dog Lake Campground
- Big Sage Road Modoc County
- Goose Lake State Park
- Drews Reservoir
Campgrounds
- Janes Reservoir
- Jane's Reservoir Campground
- Reservoir C
- Reservoir C Campground
- Lassen Creek Campground
- Lassen Creek
Paddle runs
- Wilcox Spring To Clear Lake National Wildlife Refuge Boundary
- Sally's Camp To Confluence With Willow Creek
- Deep Creek
- Headwaters To Sw1/4 Of Sec 29, T40s, R22e
- Twelvemile Creek
More reservoirs
Track Green Tank 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 Green Tank
Where does the data for Green Tank 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 Green Tank.