“Brave Little State” Explores CSOs

On May 5, Vermont Public Radio released a new podcast in its series “Brave Little State,” focusing on the challenges of combined sewer overflows (CSOs).  The feature stemmed from a question offered by Winooski resident Mike Brown, who asked “Why do we have pollution in Lake Champlain, and what can we do about it?”

His question triggered a month-long investigation by reporters Angela Evancie and Taylor Dobbs and resulted in a 28-minute program that describes CSOs – what they are, what causes them, and why they’re so hard to manage – and explores the problem of aging water/wastewater infrastructure.

Led by Jeff Wennberg, Commissioner of Public Works for Rutland City, the team visited one of Rutland’s four CSO outflow stations to learn more about the technologies and practices affecting combined stormwater/wastewater systems. The Rutland system was expanded to limit overflows to about two heavy precipitation events per year.  However, due to changing weather patterns and the growth of the region’s developed landscape, stormwater volume has increased dramatically.  The system now experiences 20 to 30 CSO events per year.

Wennberg, who would prefer to see no more than one every five years, emphasized that his department watches weather reports with extreme vigilance – and, often, extreme anxiety. Even so, he defended combined sewers as doing a superb job, saying that overflows constitute only a tiny proportion of the enormous amount of urban stormwater these systems treat.

Wennberg believes a three-pronged approach is needed to reduce CSOs: “green” infrastructure that encourages infiltration; “grey” infrastructure in the form of large, temporary holding tanks; and “data” infrastructure — technologies capable of rapidly-adaptive responses to unpredictable flow volumes.

As all operators know, it all comes down to “Who’s going to pay for it, and how soon?” Wennberg said.  That question brought the reporters to the Statehouse, where they interviewed Rep. David Deen, chair of the House Natural Resources, Fish and Wildlife Committee.  Deen explained that declining federal funding has limited the state’s ability to pay for water quality management improvements.

He also said that the state’s “best bang for the buck” would be investment in reducing runoff from agricultural lands and paved surfaces, which contribute the majority of phosphorous pollution.  Dobbs reiterated that CSOs from municipal systems contribute only 4% of Lake Champlain’s phosphorous load.

The feature aired several times during May, and you can hear it in its entirety, or read a transcript, at http://digital.vpr.net/post/what-can-be-done-about-vermonts-aging-sewer-systems#stream/6

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