Making Sense of Bacteria Standards from CSO TMDL's to Protecting Whitewater Recreation: Columbus, Georgia

The Columbus Water Works has spent the last two decades navigating through federal and state environmental programs including CSOs, TMDLs, BMPs, SWPs and other acronym titled issues relating to water quality for the protection of the beneficial uses of the Chattahoochee River. In the process of complying with various regulatory programs, significant beneficial use improvements to the riverfront and the adjacent city center have resulted. Also along the way a huge database of bacteria measurements and other water quality parameters have been accumulated. Columbus used this information to demonstrate that the level of CSO control implemented is adequate to comply and protect water quality. This determination was made through a “no reasonable potential” finding that the CSO controls as implemented and operated “do not cause or have reasonable potential to cause or contribute to an exceedance” of ambient water quality criteria. The comprehensive and representative bacteria model used magnitude, duration and frequency criteria to make this determination. The State added the frequency criteria to their standards rule which made it consistent with their impaired water assessment protocol. A TMDL framework emerged for the continued improvement of tributary waterways and a local and regional monitoring network is being implemented along the way. The riverfront now includes over 20 miles of walks and trails and a 2.5-mile whitewater venue for kayaking and fish spawning habitat being implemented through the removal of two low-head dams and construction of sluices and flow control structures. These water use changes will create new beneficial use criteria. The comprehensive and representative modeling effort established for the TMDL framework was then used to assess and positively determine compliance for the new recreational use.