Aug. 23, 2010's Federal Register had a mostly overlooked notice calling for a 45-day public comment period for the draft document titled, Climate Change Vulnerability Assessment: Four Case Studies of Water Utility Practices.

The draft document, (read it here – pdf) prepared by the National Center for Environmental Assement, offers four previews of how a changing climate (for whatever reason – we're not getting into this today) might affect the water treatment biz.

Remember, it's a draft – until the public has reviewed the findings none of this stuff is official.

Four water utilities in Contra Costa, Calif., New York City, Seattle and Spartanburg, S.C., were asked to assess their vulnerability to climate change and note some preparatory actions. They're not a perfect sample of WWTPs, rather the point was to choose facilities that were already taking some initiative, and to highlight those initiatives. The actions being taken these utilities are worth a look, especially for those worried about future water shortages.

The East Bay Municipal Utility District in Contra Costa highlighted its Water Supply Management Program to identify dry-year needs. They studied historical hydrology, and modeled the effects that these historical realities might have faced given situations such as a 4-degree rise in temperatures, or a long-term drought.

New York looked at problems with salinity in the Hudson and with water supply issues, and realizing there was a potential problem, shifted focus toward improving its reservoir.

Seattle, working with a University of Washington group, projected a notable decrease in water supplies in any scenario, and went about testing assumptions for how they might handle this decrease, also noting some potential adaptations they might make in the future.

Finally, Spartanburg, an example of a much smaller utility, couldn't do the modeling of its big brothers, but had direct evidence from recent weather events, including droughts and hurricanes, to use for study. Spartanburg also offered an interesting conclusion about their discharge loads, which would likely need to be curtailed in the face of lower flows in receiving streams.

The public comment period ends Oct. 7, 2010. Until then, the reports are not official. They are, however, as good of a starting point as any for any WWTP manager looking to build a plan for future water shortages and population needs.