Mystery Valley Lake Dam dam
Mystery Valley Lake Dam
Mystery Valley Lake Dam, located in DeKalb, Georgia, is a local government-owned structure designed by the Soil Conservation Service (SCS) with a primary purpose of recreation. Completed in 1960, this earth dam stands at a height of 23.6 feet and has a maximum storage capacity of 200 acre-feet. Despite its age, the dam is in poor condition and has a high hazard potential, with a moderate risk assessment rating.
The dam's inspection frequency is every two years, with the last assessment conducted in January 2021 revealing its poor condition. The dam features uncontrolled spillways and outlet gates, posing potential risks in the event of a significant weather event or natural disaster. It is regulated and inspected by the Georgia Safe Dams Program, indicating a commitment to ensuring the safety and integrity of the structure. With its location in a highly populated area and the potential for significant environmental impact in case of failure, Mystery Valley Lake Dam is a critical infrastructure that requires ongoing monitoring and maintenance to mitigate risks and protect both the community and surrounding ecosystem.
Water resource and climate enthusiasts will find Mystery Valley Lake Dam a fascinating subject for study and advocacy, given its historical significance, recreational importance, and current challenges. Its condition and hazard potential highlight the importance of proactive management and investment in infrastructure to ensure the safety and sustainability of water resources in the face of changing climate conditions. Efforts to address the dam's poor condition and high hazard potential can serve as a model for resilience and adaptation in the face of climate-related risks, emphasizing the critical role of infrastructure in safeguarding communities and ecosystems.
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 Mystery Valley Lake Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Yellow River At Ga 124 | 74 cfs | → |
| Yellow River At Pleasant Hill Rd | 72 cfs | → |
| No Business Creek At Lee Road | 3 cfs | → |
| South River At Flakes Mill Road Nr Atlanta | 34 cfs | → |
| Big Haynes Creek At Lenora Road | 9 cfs | → |
| South River At Klondike Road | 103 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Mystery Valley Lake Dam.
Boat launches
- Lakeshore Drive Henry County
- Chattahochee River Park Peachtree Corners
- Saint Ives Country Club Parkway Johns Creek
- West Palisades Vinings
- Cobb Parkway South Vinings
- Johnson Ferry Road Southeast Sandy Springs
Campgrounds
- Stone Mountain Campground
- Stone Mountain Park Campground
- James Shackleford County Park
- Dobbins Lakeside Military
- Fort Yargo State Park
- Newton Factory Shoals Rec Area
Fishing spots
- Lake To-Lani
- Davidson Mountain Nature Preserve
- Avondale Lake
- Chapel Hill Park
- Buena Vista Lake
- Parkers Lake
Track Mystery Valley 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 Mystery Valley Lake Dam
Where does the data for Mystery Valley 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 Mystery Valley Lake Dam.