Una S Johnson Dam dam
Una S Johnson Dam
Una S Johnson Dam, located in Cherokee, South Carolina, is a privately owned earth dam constructed in 1958 primarily for recreational purposes. With a height of 47 feet and a length of 260 feet, the dam boasts a storage capacity of 331 acre-feet, making it a significant feature on the TR-Broad River. While the dam's hazard potential is rated as low, its condition assessment is unfortunately poor as of the last inspection in September 2017.
Despite its poor condition, Una S Johnson Dam continues to serve as a popular spot for water resource and climate enthusiasts, offering a surface area of 19 acres for recreational activities. The dam's uncontrolled spillway type and moderate risk assessment of 3 indicate a need for ongoing monitoring and maintenance to ensure the safety of the surrounding community. With the South Carolina DHEC overseeing state regulation and enforcement, efforts are being made to address the dam's structural issues and improve its overall condition.
As a vital part of the Charleston District's water infrastructure, Una S Johnson Dam plays a crucial role in water resource management and flood control along the Broad River. With its proximity to residential areas, the dam's condition and safety are of utmost importance, prompting the need for regular inspections and risk management measures to mitigate any potential hazards. For water enthusiasts and climate advocates alike, staying informed about the dam's status and maintenance efforts is essential to preserving this recreational and environmental asset for future generations.
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 Una S Johnson Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Broad River Below Cherokee Falls | 576 cfs | → |
| Broad River Near Gaffney | 1,890 cfs | → |
| Broad River Near Blacksburg | 350 cfs | → |
| Broad River Near Carlisle | 916 cfs | → |
| Lawsons Fork Creek At Spartanburg Sc | 30 cfs | → |
| Wildcat Creek Below Rock Hill | 3 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Una S Johnson Dam.
Boat launches
- Boatshore Road York County
- Sandy Ford Road 1925, Chesnee
- John H. Moss Lake Recreation Park
- Windward Drive Tega Cay
- Lakeshore Drive Cleveland County
- New Gray Rock Road Tega Cay
Campgrounds
- Poulous Loop Group Camp
- Woods Ferry Recreation Area
- Woods Ferry
- Garner Creek Backcountry Campsite
- Garner Creek
- Chester State Park
Track Una S Johnson 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 Una S Johnson Dam
Where does the data for Una S Johnson 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 Una S Johnson Dam.