We hear a lot these days from folks concerned about federal clean water protection programs. They say things work best when decisions are made at the local government level. One size doesn’t fit all, they say. In some cases, that may be true.
Still, it’s surprising that special interests, such as the Homebuilders Association of Chattanooga, have chosen to speak out against Chattanooga’s locally-decided stormwater protection measures. As I understand it, their argument isn’t founded on new or better local science or information, but simply on the fact that some of Chattanooga’s protection requirements are more stringent than others.
In coming up with what was right for Chattanooga, the city’s water quality staff studied scientific information and creek data. After public input and careful analysis, they presented an ordinance to the Chattanooga City Council that was adopted in 2014. Among other things, the ordinance established guidelines for property development and redevelopment requiring that, where feasible, stormwater stay on property after a rainfall. Such a practice allows water to seep into the ground instead of carrying pollutants and sediment to neighboring properties and natural water bodies.
Dr. Barbara MillerFurther, according to ordinance, the stay-on-volume (amount of runoff) that must be held on a property is the equivalent of 1 inch of rainfall for most of the city, but 1.6 inches for South Chickamauga Creek.
Why did the city decide the South Chickamauga Creek watershed should have a greater retention requirement than the minimum suggested by state regulators? Because South Chickamauga Creek is highly floodable, is home to endangered species, has been found to be impaired by sediment and habitat alteration, is the source of much of the drinking water for Chattanooga residents, and is part of sewage consent decree remedies.
Finally, the existing ordinance requires that stormwater calculations, and associated building fees, be determined based on the whole property size. Proposed changes to the ordinance, strongly supported by home builders, would use only the area of planned impervious surface as a basis for calculations, hence reducing the amount of water to be stored as well as home-building fees. This change, however, significantly reduces the effectiveness of stormwater management, resulting in poorer control of property runoff, with likely reduced protection downstream.
Much to their credit, Chattanooga’s leaders have long taken to heart their mission to provide for the health and safety of the city’s residents and environment. That includes their decision to transition away from the traditional practice of routing stormwater directly into urban waters (along with motor oil, lawn fertilizer, sediment, trash and assorted other pollutants) and instead adopt newer and smarter ways of managing stormwater runoff: pervious pavers, rain gardens, bioswales, plant buffers, green roofs and similar innovations. Such green landscaping tools have been shown not only to cost less, but look more attractive and require less maintenance over time. By releasing less water over a longer period, they significantly reduce the risk of floods. (Think Houston.)
Unless and until the city has a thoughtful reason for doing otherwise, officials should maintain the 1.6-inch stay-on volume for South Chickamauga Creek. The current ordinance, based on careful analysis and citizen input, protects South Chickamauga Creek and serves the citizens of Chattanooga well. It would be very short-sighted to relax existing regulations at this time. One size does not fit all.
Dr. Barbara Miller is the retired lead water specialist and program manager for the World Bank and a former TVA manager of flood risk reduction.