Experts: Algae reduction strategies are working
July 10, 2018
This spring, a rapid increase in the amount of Geosmin, one of several substances produced by algae that give water a disagreeable taste and odor, was observed in Reservoir #1 and Lake Bowen. In response, Spartanburg Water contracted Aqua Services, a licensed applicator, to treat affected areas of the lake with an algaecide as had been done successfully on numerous occasions in the past. Unlike in past treatments, significant numbers of stressed and dying fish were observed over several days following this application. Spartanburg Water, along with SCDHEC, the South Carolina Department of Natural Resources, Clemson University School of Agriculture and Auburn University immediately began an investigation. Here are the findings of the experts:
- The algaecide, Current, was an appropriate product for the purpose and was applied in full compliance with all regulations by licensed applicators. The amount used was less than half the allowable amount for our lakes.
- Fish examined independently by Clemson and Auburn Universities did not show effects of copper, the active ingredient of Current, sufficient to explain the deaths.
- Deaths occurred during spawning season, a time that is normally stressful for fish.
- Most dead fish were discovered in shallow water where spawning beds are located.
- Water temperatures were unusually high, especially in shallow areas. Warmer water contains less dissolved oxygen than cooler water, other conditions being equal, and can cause stress to fish.
- Storm events occurred during the time just before and during the deaths. Heavy rainfall washes contaminants like fertilizer, pesticides and bacteria from the banks into the water. It also causes rapid changes in lake temperature and lowers the ability of the lake to resist changes in pH and other chemical conditions. This is also known to cause stress to fish.
So what caused the fish to die? The answer is likely “all of the above,” a combination of stresses occurring at the same time that together just proved too much for them. Spartanburg Water continues to work with Clemson University and other experts to refine and improve our source water algae management plan. This includes measures to improve water quality and control nutrients entering the lake through establishment of sound land use measures such as shoreline buffers.