City officials have been in negotiations for many months with federal and state regulators to develop a schedule of major improvements in Chattanooga's sanitary sewer system to help prevent hazardous overflows of raw sewage and meet long-neglected Clean Water Act standards. The consent decree filed on Tuesday in federal court here makes plain the onerous cost of upgrading or separating the area's combined sewer/stormwater-runoff system: It will cost approximately $250 million, with the most important projects to be accomplished in the next five years.
That is, to be blunt, a whopping figure: It admittedly will drive regular annual sewer rate increases of up to 10 percent for at least the next five years. But given the scope of the work on a system that was begun in the 1880s - and that for generations has routed stormwater runoff into the sewer lines of a metropolitan area that now numbers around 400,000 in total population - it is neither surprising, nor out of line with similarly mandated work in many other cities' metropolitan areas.
Knoxville, for example, has agreed to a $540 million sewer improvement plan. Atlanta's fix will cost $3 billion by the time it's finished. Philadelphia expects to whittle its $13 billion plan down to $3 billion by using innovative green infrastructure to keep stormwater runoff - the driving force for overflows of raw sewage here and in many older cities - out of its sewer lines. That's a lesson that city officials plan to explore.
Half of a $476,400 civil penalty attached to the consent decree, for example, will be used by the city to develop model green infrastructure projects in the Highland Park area to keep stormwater runoff out of the sanitary sewer lines. These projects will capture and route runoff through use of green roofs, downspout cisterns, permeable pavement, retainment ponds and green spaces with swales, which are sculpted earth berms shaped to form temporary shallow wetlands in parks, open spaces and yards.
City officials also agreed to an $800,000 restoration of a stream that empties into South Chickamauga Creek near the north end of the Brainerd Levee, off Wilcox Boulevard. Other scheduled improvements will follow an audit and comprehensive survey of sewer line capacities and maintenance requirements in five priority sewer basins in the first five years, and 24 other basins in the next 10 years. Improvements also will be made be in eight sewer overflow treatment facilities, pumping systems and underground combined sewer/runoff detention tanks. Outfall systems along Chattanooga Creek and other streams will also be improved.
Major improvements also will be made at the Moccasin Bend sewer treatment plant, a regional facility which also serves the unincorporated areas of the county, the Hamilton County Water and Waste Treatment Authority, and most of the municipalities surrounding Chattanooga, and parts of the three neighboring north Georgia counties.
The latter reflects the enormity of regional sewer problems here. Though the city has spent more than $53 million since 1992 in continuing upgrades of the Moccasin Bend plant and re-engineering of the city's combined sewer/stormwater runoff lines, growth throughout the area has contributed to excessive loads at the Moccasin Bend treatment plant, and to overflows above it.
The city's scheduled fix must be accompanied by stormwater containment throughout the area served by the plant if overflows of raw and partially treated sewage is to be contained. But this isn't just the city's problem; it's a regional problem, and the bill will be reflected in sewer-users' fees throughout the plant's service area.
The flipside of the cost shouldn't be lost. The goal is to keep sewage out the Tennessee River to make the river cleaner and healthier. That's worth the cost of the fix.