Gridley Dam dam
Gridley Dam
Gridley Dam, located in Chandlerville, Illinois, is a state-owned structure designed by the Illinois Department of Natural Resources. Completed in 1998, this earth dam serves a primary purpose of recreation, providing a serene reservoir with a surface area of 24.6 acres and a maximum storage capacity of 475 acre-feet. Situated on the tributary of Panther Creek, the dam stands at a height of 51 feet and stretches 414 feet in length, offering visitors a tranquil setting for outdoor activities like fishing, boating, and picnicking.
Despite its low hazard potential, Gridley Dam is subject to state regulation, inspection, and enforcement by the Illinois Department of Natural Resources. With a moderate risk assessment rating of 3, the dam's condition assessment and emergency preparedness details are currently unavailable. The spillway, with a width of 120 feet, is uncontrolled, and the outlet gates function in a similar manner. Although the dam has not been modified in recent years, regular inspections are conducted every five years to ensure its safety and structural integrity.
Gridley Dam's location in Cass County, Illinois, under the jurisdiction of the St. Louis District, offers a peaceful recreational retreat for water resource and climate enthusiasts. The dam's strategic position on the tributary of Panther Creek provides a vital source of water storage for the surrounding area, with a drainage area of 0.33 square miles. Visitors can enjoy the natural beauty of the reservoir while appreciating the dam's role in water conservation and leisure activities.
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 Gridley Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Sangamon River Near Oakford | 3,110 cfs | → |
| Sangamon River At Petersburg | 1,960 cfs | → |
| Salt Creek Near Greenview | 1,020 cfs | → |
| Spring Creek At Springfield | 117 cfs | → |
| Sangamon River At Riverton | 1,610 cfs | → |
| La Moine River At Ripley | 416 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Gridley Dam.
Boat launches
- Gridley Road Cass County
- County Highway 11 Cass County
- Gurney Road Cass County
- West Jefferson Street 598, Havana
- Waverly Lake Road Morgan County
- East Lake Shore Drive 182, Springfield
Track Gridley 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 Gridley Dam
Where does the data for Gridley 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 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 Gridley Dam.