Dam Report

Johnson Lake Dam dam

South Carolina, USA Bradley Mill Branch Hazard Low
Today high
--
Tonight low
--
Dam height
15ft
Hazard rating
Low
Loading current conditions…
Loading next 24 hours…
Loading 7-day outlook…
Johnson Lake Dam -- None dam
Johnson Lake Dam None · Bradley Mill Branch
About this dam

Johnson Lake Dam

Johnson Lake Dam, located in Aiken, South Carolina, is a privately owned structure that serves multiple purposes, including recreation and other activities. Completed in 1958, this earth dam stands at a height of 15 feet and spans a length of 525 feet, with a storage capacity of 99 acre-feet. The dam is situated on Bradley Mill Branch and is regulated by the South Carolina Department of Health and Environmental Control (DHEC).

Despite being classified as having a low hazard potential, the dam's condition assessment was rated as poor during its last inspection in August 2017. The inspection frequency is set at every five years, highlighting the need for regular monitoring and maintenance to ensure the safety and integrity of the structure. With a history of modification and a designated emergency action plan, Johnson Lake Dam remains a vital component of water resource management in the area.

As an enthusiast of water resources and climate, the Johnson Lake Dam presents an intriguing case study in dam management and maintenance. Its history, design characteristics, and current condition offer valuable insights into the challenges and responsibilities associated with ensuring the safety and functionality of essential infrastructure in the face of changing environmental conditions.

StateNone
River / streamBradley Mill Branch
NID IDSC01303
Owner typePrivate
Primary purposeOther
Dam typeEarth
Year built1958
Dam height15 ft
Dam length525 ft
Max storage99 AF
Normal storage62 AF
Surface area20.0 ac
Hazard potentialLow
ConditionPoor
Last inspectionThu, 10 Aug 2017 00:00:00 GMT

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.
Detailed forecast

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.

Hourly detail

Next 5 days, hour by hour

Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.

Loading hourly forecast…
Deep dive

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.

TimeConditionTemp (°F)Snow (in)Rain (in)Humidity (%)Wind (mps)Wind dir
Loading detailed forecast…
Long-term outlook

15-day temperature & precipitation

Daily temperatures, snow, and rain projected over the next two weeks.

Loading 15-day outlook…
Regional inflow

Nearby streamflow gauges

USGS streamgauges around Johnson Lake Dam -- inflows here typically show up in storage 24-72 hours later.

Track Johnson 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.

FAQ

About Johnson Lake Dam

Where does the data for Johnson 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 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.