Stumps, logs and lost fishing lures are appearing lately as Bulloch County area ponds, like others across the state, are dropping in water levels.
Whether a pond is spring-fed, stream-fed or fills up from rainfall runoff, the drought is affecting them all. A drive through the county will show most ponds, regardless of whether they are used for irrigation, are unusually low.
This can cause problems for fish and wildlife, said Georgia Southern University biology professor Dr. Steve Vives.
Ponds “support fish and a lot of other wildlife,” he said. “Wading birds, frogs, toads, turtles — it’s healthy to have good ponds.”
The water table is low due to drought, which affects spring-fed ponds that feed from the aquifer. Streams and rivers are low due to a rainfall deficit, and creek-fed ponds are low for that reason. And ponds that rely on rainfall runoff, well, when there is no rain, there is no runoff, he said.
Low pond levels “reduce the living area, and fish lose habitat,” he said. This leads to oxygen problems, and when plants begin growing and flourishing where water once stood, it creates further problems.
When the water levels return, those plants die and decompose, causing further oxygen depletion when bacteria caused by decomposition consume the oxygen, he said.
Low water levels encourage algae bloom too, which depletes oxygen. Removing plant growth around and in ponds while the water is still low may help the pond’s health when water levels rise, he said.
Bulloch County Agent Wes Harris said a lot of dry periods, especially in July and August, pulled a great deal of water from ponds, especially when farmers found an urgent need to irrigate crops. He said he saw a pond in the area that was about 80 percent drained, although other ponds in the county have fared better.
“The issue is stress on fish if you don’t have a good stratified layer (of oxygenated water.) The oxygen level is stabilized by thermal layers, warm on top and cooler on bottom,” he said.
When a storm comes or a sudden cooling period arrives, it can “turn the thermal layers upside down” and cause fish to die, especially when the pond level is low, he said.
Fortunately, the majority of farmers won’t be irrigating any more this year, and ponds used for that purpose may be able to recover with sufficient rainfall, he said.
Ron Milligan, regional representative with Georgia Soil and Water Conservation, said ponds are not only important for wildlife, but for recreational purposes, livestock water sources and irrigation for crops.
Regardless of how a pond gets its water, there are different variables that determine which types are depleted the quickest, he said.
Pond water level depends on the pond’s location, elevation and relationship to the aquifer; how much rainfall is received in an area and how low the creek or stream flow into the ponds.
And while Bulloch County ponds do appear to be low in many areas, “we’re in a little better shape than in previous years,” Harris said.
Holli Deal Bragg may be reached at (912) 489-9414.