Mermet Dam dam
Mermet Dam
Mermet Dam, also known as Mermet Lake, is a state-owned structure in Massac, Illinois, primarily designed for recreation purposes. Completed in 1950, this earth dam stands at a height of 10 feet and spans a length of 20,000 feet, with a storage capacity of 2,800 acre-feet and a surface area of 0.7 square miles. Situated on the Trib Tucker Ditch, the dam's controlled spillway is 16 feet wide, with a maximum discharge capacity of 150 cubic feet per second.
Managed by the Illinois Department of Natural Resources (IDNR), Mermet Dam has a low hazard potential and is subject to regular state regulation, inspection, and enforcement. Despite its very high risk assessment rating, the dam's condition assessment is currently not available, with no emergency action plan in place. The dam's outlet gates are operated by a slide (sluice gate) system, and it is located within the St. Louis District of the US Army Corps of Engineers jurisdiction. For enthusiasts interested in water resources and climate, Mermet Dam presents an intriguing case study in recreational dam infrastructure management and risk mitigation.
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 Mermet Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Cache River At Forman | 7 cfs | → |
| Bayou Creek Near Grahamville | 5 cfs | → |
| Little Bayou Creek Near Grahamville | 1 cfs | → |
| Ohio River At Metropolis | 444,000 cfs | → |
| Massac Creek Near Paducah | 2 cfs | → |
| Lusk Creek Near Eddyville | 11 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Mermet Dam.
⚓ Boat launches
- Mermet Lake Road Massac County
- Metropolis Boat Ramp
- Metropolis Ferry Landing Road Mccracken County
- Access Road Pulaski County
- Metropolis
- Mill Road Pulaski County
⛺ Campgrounds
- Cedar Grove Camping Area
- Turkey Ridge Tent Campground
- Camp Ondessonk
- Pearcy Camp
- Red Bud Campground
- Teal Pond Campground
🎣 Fishing spots
- Little Cache Lake #1 (Bowman Lake)
- Dutchman Lake
- Lake Of Egypt
- One Horse Gap Lake
- Whoopie Cat Lake
- Lake Tecumseh
🛶 Paddle runs
- Bridge At Eddyville Blacktop To Confluence With Ohio River At Golconda,Il
- 1 Minle Southwest Of Delwood, Il (Sec. 18, T11s, R13e) To Reesville, 1/4 Mile South Of The Confluence With Sugar Creek
- Source, About 2 Miles East Of Delwood, Il (Sec 10, T11s, R6e) To Bridge At Eddyville Blacktop (Se1/4,Sec.16,T12s, R6e)
- Wallace Cemetery Approx 2.5 Miles Nw Of Herod, Il To Confluence With Ohio River At Golconda Jobs Corp Center
- 1 Mile West Of Alto Pass, Il To 1/2 Mile South Of Confluence With Clear Creek, West Of Trail Of Tears State Forest
- Russell Cemetery, Approx 1/4 Mile North Of Karbers Ridge Road To Proclamation Boundary, 1 Mile Nw Of Elizabethtown,Il
Track Mermet 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 Mermet Dam
Where does the data for Mermet 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 Mermet Dam.