Arrowhead Lake Dam dam
Arrowhead Lake Dam
Arrowhead Lake Dam, located in Johnston City, Illinois, is a private dam primarily used for recreational purposes. Standing at a height of 16 feet and with a length of 840 feet, this earth dam holds a storage capacity of 355 acre-feet of water. Completed in 1963, the dam overlooks the scenic TRIB LAKE CREEK and offers a surface area of 39 acres for visitors to enjoy various water activities.
Managed by the Illinois Department of Natural Resources, Arrowhead Lake Dam is regulated, inspected, and enforced to ensure its safety and compliance with state standards. Despite its significant hazard potential, the dam has a moderate risk assessment rating. While information on the dam's condition assessment is not available, its emergency action plan status and risk management measures remain undisclosed. The dam features an uncontrolled spillway and outlet gates, reflecting its design and functionality for recreational use.
With its picturesque location and recreational appeal, Arrowhead Lake Dam serves as a popular destination for water resource and climate enthusiasts in Williamson County, Illinois. The dam's construction and operation reflect a balance between providing recreational opportunities and maintaining safety measures to mitigate potential risks. As a privately owned structure, Arrowhead Lake Dam stands as a testament to the importance of sustainable water resource management and climate-conscious infrastructure development in the region.
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 Arrowhead Lake Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Crab Orchard Creek Near Marion | 4 cfs | → |
| Big Muddy River At Plumfield | 461 cfs | → |
| South Fork Saline River Nr Carrier Mills | 526 cfs | → |
| Big Muddy River At Rte 127 At Murphysboro | 5,680 cfs | → |
| Rayse Creek Near Waltonville | 3 cfs | → |
| Lusk Creek Near Eddyville | 10 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Arrowhead Lake Dam.
Boat launches
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Campgrounds
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Fishing spots
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River runs
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About Arrowhead Lake Dam
Where does the data for Arrowhead Lake 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 Significant 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 below 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.
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.