Thunder Hollow dam
Thunder Hollow
Thunder Hollow is a privately owned earth dam located in Union, Tennessee, specifically in the city of Pleasant Grove. Built in 1974, this dam stands at a height of 46 feet, with a hydraulic height of 36.6 feet and a length of 357 feet. It serves as a structure on the Bullrun Creek, providing a storage capacity of 34 acre-feet with a normal storage level of 25 acre-feet.
Despite being privately owned, Thunder Hollow is not regulated by the state and does not have any associated state permitting, inspection, or enforcement. The dam has a significant hazard potential and is classified as having a moderate risk level. It has not been rated for its condition assessment, and the last inspection was conducted in February 2020 with an inspection frequency of every 5 years. The spillway type is uncontrolled, and there are no outlet gates associated with the dam.
For water resource and climate enthusiasts, Thunder Hollow presents an interesting case study of a privately owned dam in Tennessee. Its location on Bullrun Creek and its significance in terms of hazard potential and risk assessment make it a noteworthy site to monitor and study in the context of water resource management and climate resilience. As an earth dam with a moderate risk level, Thunder Hollow highlights the importance of regular inspections and maintenance to ensure the safety and integrity of such structures in the face of changing environmental conditions.
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 Thunder Hollow -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Bullrun Creek Near Halls Crossroads | 16 cfs | → |
| Beaver Creek At Solway | 32 cfs | → |
| Powell River Near Arthur | 297 cfs | → |
| Little Pigeon River At Sevierville | 162 cfs | → |
| Little River Near Alcoa | 131 cfs | → |
| Clinch River Above Tazewell | 593 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Thunder Hollow.
Boat launches
- Highway 33 South 5799, Claiborne County
- Nance Ferry Road Grainger County
- Claiborne County
- Mountain View Road 332, Norris
- James White Parkway Knoxville
- Mead's Quarry Lake Ramp
Campgrounds
- Big Ridge State Park
- Loyston Point
- Anderson County Park
- Clinton / Knoxville North Koa
- East Campground
- Camp Cargill
Fishing spots
Track Thunder Hollow 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 Thunder Hollow
Where does the data for Thunder Hollow 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 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 Thunder Hollow.