Many stakeholders have expressed their concern with the outflows from the reservoirs identified in our ten-week projection. The projection forecasts an increase in outflows to 4,000 cubic feet per second (cfs) weekly average from Lake Thurmond in February. This projection is in accordance with the current drought plan based on the July 2012 Environmental Assessment (or EA), which was approved by the state and federal resource agencies.
As with earlier versions of the plan, the latest version calls for a return to higher flows when both Lakes Hartwell and Thurmond rise two feet above the previous drought trigger. Our projection identifies the lake levels will rise to 648 feet and 318 feet (two feet above Drought Trigger Level 3) for Hartwell and Thurmond respectively in February. Therefore, according to the approved drought plan, flows will return to either 4,000 cfs or 3,800 cfs depending on the percent of inflows for the Broad River. The EA and the Drought Plan use stream flow in the Broad River as a proactive indicator during Drought Levels 1 and 2. If stream flows at the Broad River gauge are less than or equal to 10 percent of the historical flow rate (calculated over a 28-day average), the Corps of Engineers will reduce outflows to 3,800 cfs in Level 2. If Broad River flows are higher than the 10-percent historical flow rate, the Corps of Engineers will set outflows to 4,000 cfs in Level 2. Currently Broad River flows are well above 10 percent historical flow rate (as of Jan. 24, 2013, Broad River flows were 36 percent for the 28-day average streamflow).
However, we want to reassure you that we continue to work with state and federal resource agencies to minimize the adverse effects of this drought for the entire spectrum of stakeholders. As such, we are seeking agency approval to deviate from our approved plan and keep outflows at 3,800 cfs up to Level 1. This is an effort to retain more water in the reservoirs for later use. Since this action would deviate from the approved Drought Plan, we must coordinate and obtain resource agency approval to proceed. We will keep you updated on the latest via posts to this site.
As a reminder, we are scheduled to increase outflows from 3,100 cfs to 3,800 cfs on Feb. 1 as the weather continues to warm. This is necessary because the water temperature rises this time of year, leading to the beginning of spawning season for anadromous fish such as the endangered shortnose sturgeon. For more details see the description of the new drought plan in our August 2012 news release.
The EA and Finding of No Significant Impact is available on the Savannah District website at: http://www.sas.usace.army.mil/reports.html.
Check back with us here for updates or subscribe to receive emails when we make a post. Thank you for your patience and understanding. ~Russell Wicke, Corporate Communications