New approach urged for flood planning

01:00 AM EST on Friday, January 27, 2006

BY JOHN HILL
Journal Staff Writer

BLACKSTONE, Mass. -- In the 1950s, Woonsocket was ravaged by a flood that swamped the Social Street area. The federal, state and local response was to spend $14 million over a decade on a dam and four flood gates at Market Square, pump stations and concrete-lined channels.

But after the October 2005 flooding of the Blackstone, an array of environmentalists and planners gathered here yesterday said the 21st-century response should be improved wetlands and subdivision regulations.

An audience of about 70 people from municipalities and organizations in Rhode Island and Massachusetts convened at the public library here to assess how communities along the Blackstone River might mitigate the effects of future severe rainstorms.

Several speakers said the rains of Oct. 12 to 15 -- when nearly 10 inches fell on Providence and 14 inches on Woonsocket -- were so heavy that there was nothing that could have been done to prevent flooding. Donna Williams, of MassAudubon, one of the event's sponsoring organizations, cited measurements in Woonsocket that showed the river's flow going from 180 cubic feet per second to 18,000 cubic feet during the flooding.

How much fell from the sky was the responsibility of Mother Nature, she said, but for where it went after that, people shared the blame.

"Would that volume have been in the river if we weren't so highly developed?" she said.

That was the crux of the various presentations throughout the morning-long conference: How increasing development along the river has covered up the land and impaired nature's mechanisms for absorbing storm runoff before it can flood streets and homes.

And the consensus was that the best type of modern-day flood prevention was new building regulations encouraging housing developments that bend to fit their settings rather than leveling and paving those settings to suit the development.

Andrea Cooper, smart growth coordinator for the Massachusetts Office of Coastal Zone Management, said it's a little unfair to put all the blame on developers. She said they only bring in the types of projects that a town's zoning allows. Change the development rules, she said, and you can change the landscape.

Kim Wiegand, Lincoln town engineer and one of the speakers, said that the $14-million down-by-the-river flood control approach of the 1950s has evolved into a solution that is targeted more broadly.

She gave an example of drywells her town required be installed in a housing development along Old River Road. She said she had been concerned that rain runoff might have flooded an area downhill from the project, but it didn't happen.

Drywells are structures built underground for houses in flood-prone areas. The house's gutters that carry water off the roof are all channeled into them, so the roof runoff is piped directly underground rather than wearing channels in the ground by the downspouts. It can reduce runoff by 10 percent, she said.

"In the 1950s, you could do big projects," Wiegand said. "Now permitting is difficult, more difficult."

Richard Claytor Jr., a principal engineer with the firm of Horsley Whitten, said that even if such structures are built, rains like those in October were so severe that they'd have overwhelmed anything. He said it made more sense to come up with solutions for the smaller storms that happen more often and, over the long term, can cause serious damage as well. "It's appropriate to understand the limit of what we can do as planners and engineers," he said.

"We're not looking at the end of the pipeline," Wiegand said, "we're looking at the beginning."