If you thought the water quality regulations put in place by the Metro North Georgia Water Planning District (MNGWPD) 10 years ago would be the last word on storm water quality regulation, you're going to be disappointed. For those engineers and environmental scientists that have been paying attention, there is a new round of rule-making about to begin that will make regulation of land development activity more complicated than ever.
Recently, CE News published an article titled NPDES update: Watershed pollution diets, which discusses a comprehensive Chesapeake Bay TMDL created by the USEPA, finalized on December 29, 2010. This TMDL effectively settles years of litigation between EPA and Bay stakeholder groups, the result of which is the largest TMDL ever created by EPA. As the TMDL states in it's executive summary, it was needed because the attempts at addressing water quality over the past 25 years have largely come to naught. It encompasses 6 states and the District of Columbia, the extent of the Chesapeake Bay watershed.
Locally, Georgia EPD's premise has been to use sediment as a surrogate pollutant for storm water quality. The assumption is that non-point source pollutants attach themselves to sediment, therefore, if we can get sediment out of the water, we can remove pollution as well. This has meant that the Georgia Storm Water Management Manual has taken a "one size fits all" approach to BMP implementation in the state, and the toolbox of storm water BMPs have been the same from Albany to Rome to Savannah. Now, though, TMDLs are being implemented based on the pollutant of concern for that particular stream segment. For the really unfortunate with projects that straddle watersheds draining to impaired stream segments, you may have to deal with different regulations and BMPs for different parts of a project site.
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Surface Water Quality in Georgia
(Data courtesy of Georgia EPD) |
35% of the streams in the MNGWPD are impaired due to fecal coliform bacteria alone, and municipalities have grumbled for years that this standard could be violated in a pristine uninhabited-by-humans environment. Because, well, you know what bears do in the woods. When I look at the impaired streams in the 15 counties that comprise the Metro North Georgia Water Planning District (see graphic below), I can't help but wonder what additional measures the development community can do that will help solve the problem. The source of FC is not construction sites. Efforts to address this problem in Cities' Comprehensive Storm Water Management Plans have largely been educational, such as utility bill inserts imploring people to pick up after their pets. A few years ago, Gwinnett County thought failing septic tanks might be a primary source, but when they used infrared photography to try to spot leaking fields in older neighborhoods, they didn't find nearly as many problems as they expected.
Although no one knows for certain what EPA and EPD will do next, it's certain that, as with the Chesapeake Bay, ineffective past efforts will lead to a tightening of regulations on cities, counties, and the development community.
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Surface Water Quality in the MNGWPD
(Data courtesy of Georgia EPD) |
For example, as reported by CE News, Montgomery County, Maryland is seeing changes to its MS4 permit that will require it to retrofit 20 percent of existing impervious surfaces with stormwater management. I'm not aware of any Metro Atlanta jurisdictions that have similar conditions in their existing MS4 permits, but their inclusion would put a huge capital burden on Cities and Counties. It's likely that such a requirement would be achieved with regulation on new land development activities.
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Streams Impaired due to Fecal Coliform Bacteria Alone
(Data courtesy of Georgia EPD) |
Finally, I'm intrigued by the above graphic, which shows streams that are impaired only by fecal coliform bacteria. As I said, fully 35% of the streams in the MNGWPD are impaired by fecal coliform (FC) alone, meaning their fish and microinvertebrate communities are doing OK. If we are moving toward a TMDL standard for water quality, might we see a lessening of development related controls in these FC impaired basins? Are the controls that the development community is being made to implement through local regulation really having a mitigating effect on fecal coliform levels?
In a few short years, EPD will be renewing MS4 permits for counties and cities in the Atlanta region. Time will tell if we follow the Chesapeake Bay model.
