On August 31st 2010 the Tennessee Department of Environment and Conservation (TDEC) released a new National Pollutant Discharge Elimination System (NPDES) permit for small municipalities in the state of Tennessee. This permit, scheduled to take effect on October 1st of this year, carries with it a new direction in water quality with a number of measures that your local cities and counties will be putting into effect to step up water quality protection in your area.
The biggest change communities will see are the new requirements for green infrastructure in new and redeveloped sites. Traditionally construction storm-water has been managed by preventing erosion and storm-water runoff to the maximum extent practical through a variety of ground covers and barriers (Best Management Practices). Under the new permit, the first inch of every rainfall must be 100% managed on-site with no storm-water runoff being discharged. This will be accomplished through infiltration (water absorbed into the ground), evapotranspiration (water absorbed and transpired through plants) and/or harvesting/use (capture in a cistern or rain barrel for use on the property).
A good way to visualize this shift in dynamics is to consider the last parking lot you visited. Do you remember there being raised islands with trees or plants in them? Because these islands are elevated, their water quality value is minimal as only water that falls on them directly from the sky will be managed, hence these islands are little more than an aesthetic element. But imagine that the island is instead set down below the pavement. Rather than storm-water runoff going into a storm sewer system of concrete pipes that travel directly to your streams, this lowered island, and the vegetation in it, can now function as a rain garden absorbing a vast amount of water . You can learn more about managing wet weather with green infrastructure at the Environmental Protection Agency’s website.
Several other notable changes include an increase in municipal accountability in the form of a heightened level of documentation as well as a significantly more defined section on education and outreach as well as public involvement. Whereas the previous permit basically said “you have to do it”, the new permit further validates these components by providing substantially more guidance and sets the stage for a more effective public education effort and as anyone who has talked to me about storm-water knows, I believe public education, outreach and participation is the key to making a truly enduring difference in water quality and the environment in general.
Check out the entirety of the 2010 NPDES Municipal Stormwater Permit and make your own conclusions. If you have any questions regarding this article or have stormwater questions and/or concerns feel free to shoot me an email at [email protected] Remember, when you tug on a single thing in nature we find it attached to everything else.