Adaptive Management TMDL Approach in Columbus, Georgia

A partnership of City agencies, regional businesses and environmental stewards in the Middle Chattahoochee River Watershed have implemented a community amenity approach to support demonstration of innovative stormwater technologies to restore urban waterways and protect drinking water supplies. Four demonstration projects are being implemented representing “further reasonable progress” which is the basis of an adaptive management approach to the Total Maximum Daily Load (TMDL) regulatory process. Adaptable technologies are being implemented through EPA 319(h) grants. The Columbus Water Works conceived these projects after a decade of watershed studies and CSO infrastructure controls for reducing water quality impacts during wet weather conditions. Findings from these prior efforts have led to the prioritization of watershed issues and identification of existing infrastructure that can be optimized for quality protection combined with waterway restoration including community amenities.The Georgia Environmental Protection Division (EPD), under Federal consent order has issued TMDL allocations for 303(d) and 305(b) listed waters in the region, mostly for bacteria and aquatic biology. The Columbus program has demonstrated compliance with existing and proposed EPA ambient water quality criteria for fecal coliform and E. coli for all but one stream. An intensive sampling and BASINS model calibration process was used to determine compliance with geometric mean and quantify site-specific confidence limits for maximum value criteria. One demonstration project will apply UV disinfection to protect the recreational uses of the premier park in Columbus (Lake Bottom Park). A portion of this demonstration will include creek corridor restoration providing a community amenity. The completed project is anticipated to finalize the TMDL Implementation Plan and remove this water from future listings.The TMDL planning process identified technologies coupled with existing drainage infrastructure that can be optimized to attenuate stormwater hydrographs to reduce downstream embankment erosion thereby protecting the fish communities. Attenuation controls are also being fitted with solids separation and filter technologies to remove flushed pollutants from wet weather flows that correlate to macroinvertebrate biology. Two of the four demonstrations will use concrete drainage structures to cost-effectively implement control facilities. A third demonstration is using a lake fore bay and lowlands to attenuate and remove sediments and fine particulates from entering the drinking water supplies. This project also improves the recreational use of this reservoir slough, which contains the City marina. The fourth demonstration is evaluating alternative high rate technologies to separate and filter heavy transportation impervious area pollutants.The demonstration technologies are being tested using on-line continuous analytical monitoring trailers to determine operation and performance characteristics. Downstream permanent water quality instrument and water quality monitoring and aquatic biology surveys are being used to illustrate benefits of watershed controls and restoration improvements. Costs and benefits will be used to determine the future iterations of the adaptive management TMDL process.