Dewatering policy in works
Flooding, contamination are issues
BY PETER B. BRACE INDEPENDENT WRITER
Led by the Department of Public Works, several town departments are helping to write a dewatering policy that would apply to projects in the downtown area near the harbor.

The policy, being worked out by DPW Superintendent Jeff Willett with contributions from the Marine & Coastal Resources Department, Conservation Commission and Building Department, will require developers to file a dewatering plan with the Building Department before building permits are issued. The town departments and boards would have to sign off on the dewatering plans before work could begin on the sites.

The new policy stems from Point Breeze developer Bob Matthews pumping water from his Easton Street property into the town's harbor outflow system and overwhelming the system several times last fall during heavy rains, causing major street flooding.

Taking notice of the round-theclock dewatering of the site, the Shellfish & Harbor Advisory Board and Marine Superintendent Dave Fronzuto - wary of the potential harm to marine life in the harbor - investigated how the town could more closely monitor and control what flows into the harbor.

"One of the things that we're concerned about is if you have Mrs. Jones with a wet basement with a sump pump and the sump pump gets discharged into the sewer drain through the washing machine hose…you don't want it to go into the sanitary sewer," said Fronzuto at the Feb. 19 SHAB meeting. "You want to be very careful in this review."

After discovering that the Point Breeze had been pumping unfiltered water into the stormwater collection system for five months, including during an astronomical high tide last Sept. 28, the DPW contacted Matthews and worked with him to develop and file a dewatering plan that filters the water before it flows into the harbor. Under this plan, water is removed from the site at a rate of 45 gallons per minute and pumped into a tank that filters out contaminants. The filtered water then flows by gravity through a three-inch pipe into one of the town's catch basins on Easton Street. In the gravity line a shutoff valve prevents flow into the catch basin or back into the tank. Should heavy rains or high tide force the DPW to shut off the Point Breeze's connection to the catch basin, the Point Breeze will be able to handle its own water.

Matthews' team of engineers presented the plan for keeping the Point Breeze dry at the Feb. 25 Planning Board meeting. During construction, steel sheeting will be driven down 19 feet into the ground around the perimeter of the property.

Collection wells placed around the property will pump water through the town-mandated filtration system then out through aboveground pipes and into the harbor via outflow pipes at Children's Beach. For permanent dewatering, when the town upgrades its downtown stormwater collection system this fall, Matthews will run his own pipes to the harbor when the town opens the streets for its project.

Dewatering plans for all downtown projects must include a monitoring program for high tides and rain events so dewatering equipment can be shut down by project developers. Projects requiring a Conservation Commission order of conditions must also have the DPW's approval, said DPW Administrator Diane Holdgate, who expects to have the dewatering forms

finalized this week. I