Rainwater cleans vehicles, river

In a demonstration project designed to conserve water, control pollutants washing into the Charles River, and recharge groundwater supplies for the dry summer months, Harvard has begun using rainwater to wash as many as 250 University-owned vehicles a week.
“We’re directly on the Charles. This [project] reduces pollutant loading into the river and makes the river more usable,” said Director of Environmental Health and Safety Joseph Griffin.

Harvard officials unveiled the project last week (April 13) in a tour offered to representatives of the Environmental Protection Agency and the Charles River Watershed Association (CWRA), who, along with NSTAR, had roles in the project.

The rainwater recycling effort is designed to reduce runoff surging into the Charles River and to save 25,000 gallons of water used for washing vehicles each year, Griffin said.

Nigel Pickering, a senior engineer with the CWRA, applauded the Harvard project, saying it is a beginning step in changing the way people think about rainwater.

Rainwater has typically been diverted into gutters and drains and allowed to run into rivers and streams. Urban areas such as Boston and Cambridge present so many hard surfaces – rooftops, sidewalks, roadways, and parking lots – that the rain runs immediately off the property and into nearby streams and rivers.

This has a couple of negative effects, Pickering said. First, it creates a large pulse of rainwater surging into rivers, carrying pollutants from the surfaces it runs over, such as spilled motor oil or antifreeze from a parking lot. The second negative effect is that it interferes with the natural process of recharging groundwater supplies.