Ninety Nine Islands dam
Ninety Nine Islands
Ninety Nine Islands is a stunning hydroelectric dam located in South Carolina, specifically in the city of Lockhart. Built in 1909 by the Southern Power Company, this concrete gravity dam stands at a height of 72 feet and stretches 1568 feet in length. With a storage capacity of 2300 acre-feet and a maximum discharge of 145,000 cubic feet per second, this dam plays a crucial role in power generation and water management in the region.
The dam's high hazard potential and moderate risk assessment highlight the importance of its maintenance and emergency preparedness. The Federal Energy Regulatory Commission oversees its operations and inspections, ensuring its structural integrity and adherence to safety protocols. The surrounding area, including the Broad River and its drainage area of 1550 square miles, benefits from the dam's regulation of water flow and storage capacity.
Enthusiasts of water resources and climate change will appreciate the significance of Ninety Nine Islands in providing renewable hydropower and managing water resources in Cherokee County, South Carolina. Its historical significance, engineering marvel, and environmental impact make it a fascinating site for exploration and study in the realm of water resource management and climate resilience.
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 Ninety Nine Islands -- 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 | 338 cfs | → |
| Broad River Near Boiling Springs | 392 cfs | → |
| Pacolet River Below Lake Blalock Near Cowpens | 88 cfs | → |
| Lawsons Fork Creek At Spartanburg Sc | 29 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Ninety Nine Islands .
Boat launches
- John H. Moss Lake Recreation Park
- Lakeshore Drive Cleveland County
- First Broad River Trail Shelby
- Sandy Ford Road 1925, Chesnee
- Boatshore Road York County
- Windward Drive Tega Cay
Campgrounds
- Garner Creek Backcountry Campsite
- Garner Creek
- Kings Mountain State Park
- Hounds Gateway Campground
- John H. Moss Lake City Campground
- Shelby Mission Camp
Track Ninety Nine Islands 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 Ninety Nine Islands
Where does the data for Ninety Nine Islands 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 Ninety Nine Islands .