A city mowing crew discovered a major fish kill early Thursday morning (8/18/2011) at the Gateway Island, just off Medical Center Parkway and behind the new Murfreesboro Medical Clinic. Field tests of the pond’s water quality, including chlorine residual, dissolved oxygen, pH, temperature and conductivity showed that all levels were well within acceptable limits.
Murfreesboro Environmental Engineer Sam Huddleston said, “When we arrived, an estimated 2,000 pounds of dead carp were discovered on the lower or western pond.” He noted that since that initial find, some living fish have been discovered in the lower pond and no dead fish were found in the upper pond.
Officials continue to be frustrated by just exactly what caused a fish kill at the Gateway Island Reception Center pond, but a wide range of theories have been looked into.
Huddleston explained, “As with most fish kills in closed pond systems, we suspected the culprit was an overnight transient water quality episode involving dissolved oxygen. Other contributing factors considered included temperature, chlorine content, and possible failure of pond water circulation equipment.”
As a precaution, city staff and contractors checked and reset these systems on Thursday. The dead fish were removed by a local environmental response company and disposed of in accordance with local and state waste management requirements. A visual check of West Fork Stones River between General Bragg Trailhead and Northwest Broad Street did not indicate any adverse impacts along that section of river.
Huddleston noted that re-use water is added to the pond. It does contain the state required level of chlorine. Reuse water is used to maintain a constant water level at the Gateway Island. It is also sprayed on the land at the Old Fort Golf Course for irrigation and landscape maintenance.
As a courtesy, Murfreesboro officials notified the Tennessee Division of Water Pollution Control and Division of Solid Waste Management. Since Gateway pond is a private pond similar to a farm pond or landscape pond, it is not subject to state requirements. The city will monitor the pond for several days to make certain additional problems do not arise.
The water feature at the Gateway Island is comprised of a 1.5-acre upper pond and six acre lower pond. It was initially constructed as one of the first storm water management projects on city owned property along the north side of Medical Center Parkway. It was enhanced to serve as a landscaped water feature for the island.