SAVANNAH, Ga. – The U.S. Army Corps of Engineers Savannah District ended the second interim of the Savannah River Basin Comprehensive Study due to inadequate analysis, a lack of full partnership concurrence on the recommendation and insufficient funding.
The draft of the report tentatively recommended further restricting the flow of water from Thurmond Dam earlier during drought; this recommendation was identified in the study as Alternative 2. Without acceptance of the Alternative 2 analysis the current drought contingency plan, also known as the “No Action Alternative,” remains in effect. The current plan was updated in 2012.
The cost of the federal study was shared with Georgia, South Carolina and The Nature Conservancy.
In addition to agency concerns over potential water quality with Alternative 2, the Corps found the hydropower effects analysis incomplete and identified other technical issues that would require additional modelling, further analysis, re-coordination among agency partners and significant adjustments to the report.
These concerns and the need to address them through more analysis, continued to prolong the study over the past few years, until the funding levels could no longer support the work needed to determine if Alternative 2 will have no significant impacts.
“Operation of the river system during drought is a critical period where many impacts from reduced flows can be unforeseen without the best datasets,” said Stan Simpson, Savannah District Water Manager. “Since the creation of the original Savannah River Drought Plan in 1989, we have further modified drought operations three times to reduce releases and I suspect [with the current plan] we’re very close to a minimum limit beyond which there would be significant adverse impacts, particularly to the environment, but also in other areas, such as energy production.
“Although there was no change to our drought plan, the study enabled us to learn a great deal more about hydrology in the basin,” added Simpson. “The model we created and refined from the study is now being used for our ongoing water supply study in the Hartwell Reservoir.”
Purpose of the Comprehensive Study
The demand for water during drought conditions strains the Savannah River Basin due to conflicting needs for water. When rain deficits cause drought, the Corps reduces outflows from the dams according to its drought contingency plan. The second interim of the Comprehensive Study aimed to address whether another update to the drought plan was warranted using data from the most recent “drought of record” for the basin, which occurred from 2011 to 2013. The intent was to determine if the plan could be adjusted to further restrict Thurmond Dam discharge without causing significant or lasting adverse impacts, according to Simpson.
In order to ensure the water management plan equitably meets competing demands for water the Corps must coordinate the plan with federal and state natural resource agencies, as well as other stakeholders, to balance the needs of the Savannah River’s upstream and downstream users.
The entire SRB Comprehensive Study is a long-term effort and broken up into several interim phases. The first phase was completed in 2006. It included a water supply survey, a flow dataset, and a computer model for the basin to help identify how changes in operations affect reservoir levels and downstream conditions. It also included the 2006 Environmental Assessment that updated the Corps’ 1989 Drought Contingency Plan in response to the then drought of record from 1998-2002.
Future interim studies within the greater Comprehensive Study will be considered in coordination with cost share partners as funding allows.
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