BATH — A plan is in the works to minimize flooding issues plaguing several areas of the city.
Public Works Director Peter Owen and Stephen Dyer of Ransom Environmental Consultants on Wednesday recommended to the City Council a prioritized series of projects, which are intended to alleviate the problem in the area of Park and Juniper streets. Residents have also complained of flooding in other parts of the city, such as Willow Street.
Much of Bath’s sanitary sewer system, such as near Park and Juniper streets, is a combined system, where overflow stormwater is discharged into sanitary sewers, Dyer stated in a Feb. 10 memorandum. While the combined sewer system is sufficiently sized to carry wastewater to the treatment plant in dry weather, wet conditions cause the amount of combined wastewater flow to often rise by at least 10 times as much, exceeding the system’s capacity and causing sanitary sewer overflows, combined sewer overflows and flooding, Dyer said.
Owen said that from a statistical standpoint, “a person who lives 80 years would see maybe three 25-year storm events … and we’ve experienced four of those in five years … events way beyond what you would normally see. … The reality is, we’re just getting a lot of rain, and the system isn’t designed for it.”
Heavy rain storms cause the sewer line between Park and Juniper streets to receive combined sewer flows that exceed its capacity, causing a backup and overflow from a manhole at the end of Juniper Street. Meanwhile, the stormwater line crossing the area also receives flows beyond its capacity, adding to the flooding, Dyer said.
The city aims to boost the system capacity, improve the system’s hydraulics, and reduce or minimize the amount of wastewater that enters the system in that area. Maine municipalities are required by the state to have a plan to eliminate combined sewer overflows.
Owen noted that “whatever systems we bring forward, they’re not going to handle the flooding that’s occurring. Our push is to separate the stormwater from the sanitary. But as far as flooding, and the problems that are occurring, there isn’t enough money to solve those problems. The only silver bullet is to just throw a billion dollars at these problems, and in this economy, that’s just not going to happen.”
Of the several projects Owen and Dyer presented, they said top priority was the extension of the Hyde Park pump station force main about 1,800 feet along Centre Street to discharge into a sanitary manhole that leads to the Commercial Street pump station. Doing so would remove 500 gallons per minute from the area of Park and Juniper streets and the Harward Street pump station.
Owen said the city is designing this project and waiting to see if it is successful in receiving $500,000 in Community Development Block Grant funds for the endeavor. The rest of the project’s $1.5 million cost would be divided by the city and the Bath Water District, Owen said.
Second priority would be a Harward Street pump station upgrade, as well as replacement of its 14-inch force main with a 16-inch pipe, which along with a smoother pipe interior would nearly double the pumping capacity of the station, Dyer said. Increasing this capacity is meant to improve conditions in Juniper and Park streets.
Owen considers stormwater drainage modifications on Winship Street to take third priority, while a Park Street to Winship Street sewer bypass and sewer upgrade for the Harward Street pump station interceptor is fourth. An inflow and infiltration study in the Park Street drainage area would take place along with the various projects.
Alex Lear can be reached at 373-9060 ext. 113 or firstname.lastname@example.org.