Recent heavy rainfall across Northeast Arkansas has led to noticeable changes in the color and water quality of several local rivers and streams, according to the Arkansas Game and Fish Commission (AGFC). From September 9 to 11, downpours followed a prolonged dry spell in the region, causing agricultural runoff to wash into waterways.
This influx of organic matter, predominantly plant material and crop residue, has temporarily shifted the water chemistry. As the plant material leaches into the water and begins to decompose, it produces a tea-like coloration commonly referred to as “tannic” water.
The decomposition process is facilitated by microorganisms that break down the organic material, consuming dissolved oxygen in the process. These lower oxygen levels, compounded by the ongoing regional heat wave, have caused significant stress on aquatic life and localized fish kills in certain areas.
The AGFC has identified the Black River, Current River, Cache River, St. Francis River, and Village Creek as being affected. Fish biologists report that verified fish deaths at these locations range from 10 to 100 individuals, though the total impacted numbers are expected to be higher.
Despite the temporary effects, the AGFC noted that these aquatic ecosystems are resilient. Fresh water continues to flow through the affected areas, diluting the runoff and replenishing oxygen levels. Encouraging signs of recovery are already being observed, with dissolved oxygen levels showing improvement in the Current River and rising above critical thresholds in the Black River.
Officials continue to monitor conditions across the region. Residents observing unusual fish kills are encouraged to report them to the AGFC by emailing AGFC.health@agfc.ar.gov or submitting reports to the Arkansas Department of Energy and Environment online.