Mertz Lake Dam dam
Mertz Lake Dam
Mertz Lake Dam is a privately owned structure located in St. Charles, Missouri, and serves primarily for recreational purposes. This earthen dam, completed in 1954, stands at a height of 24 feet and has a storage capacity of 39 acre-feet. It is situated along the TR to Creve Coeur Creek and covers a surface area of 3 acres within a drainage area of 42 square miles.
Despite its recreational function, Mertz Lake Dam poses a high hazard potential as it is not currently rated for its condition. The dam does not fall under state regulation or jurisdiction, with no permitting, inspection, or enforcement measures in place. Its Emergency Action Plan (EAP) status, risk assessment, and inundation maps remain unaddressed, reflecting potential vulnerabilities in emergency preparedness and overall risk management.
The dam's association with the Kansas City District of the US Army Corps of Engineers (USACE) is unclear, and there is limited federal involvement in its ownership, funding, design, construction, regulation, inspection, or operation. With its significant hazard potential and absence of comprehensive risk management measures, Mertz Lake Dam represents a focal point for water resource and climate enthusiasts interested in the intersection of recreational infrastructure and dam safety in the Missouri region.
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 Mertz Lake Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Creve Couer Creek At Chesterfield | 5 cfs | → |
| Caulks Creek At Chesterfield | 13 cfs | → |
| Bonhomme Creek Near Clarkson Valley | 5 cfs | → |
| Creve Coeur Creek Near Creve Coeur | 12 cfs | → |
| Grand Glaize Creek Near Manchester | 1 cfs | → |
| Kiefer Creek Near Ballwin | 3 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Mertz Lake Dam.
Boat launches
- Lake View Loop Trail Maryland Heights
- Grand Glaize Pkwy 1084, Valley Park
- Kirkwood
- Scott A Lewis Lane Cottleville
- Katy Trail 1800, Saint Charles County
Track Mertz Lake 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 Mertz Lake Dam
Where does the data for Mertz 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 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 Mertz Lake Dam.