City plans to remove invasive plants, metal junk from Charles River bank at Millennium Park, but will leave monuments to Machinery and Leather

The Boston Parks and Recreation Department plans to clean up the banks of the Charles River at Millennium Park by trying to rid the area of Japanese knotweed and oriental bittersweet and by removing various metal tanks and tubes that have popped up from the park's previous life as the Gardner Street city landfill.

Plans submitted by the department's consultant on the project, however, say the city will keep in place - and even try to protect - two large concrete items that were once considered simple demolition debris but which are now historic artifacts: friezes from Mechanics Hall along Huntington Avenue, which was once Boston's convention and meeting center, but which was torn down in the early 1960s to make way for the Prudential Center.

Then VP Richard Nixon at VFW convention at Mechanics Hall on Aug. 29, 1955 (source):

The two friezes, one an homage to Machinery, the other to Leather, sit on the riverbank along an unpaved path that follows Charles and Sawmill Brook.

The Conservation Commission, which has oversight over shorelines, is scheduled to discuss the proposal from Parks and Recreation consultant CDM Smith, at a hearing on Wednesday. The commission's online meeting begins at 6 p.m., although several other items are on the agenda before Millennium Park.

Most of the parks department's proposal involves rooting out the patches of weeds that now sprout along this path. The plans call for workers to get rid of as much of the weeds by hand as they can for two straight springs and then have a contractor apply the herbicide TZone to the Japanese knotweed patches, along with an oil agent to help get the herbicide into the plants.

After the second year of treatment, the contractor will then shower the areas with "a wetland seed mixture" to help re-establish native plants in the patches.

One of the knotweed patches:

Also in the plans: Selective pruning of trees.

In addition to the metal pipes, a contractor will remove other debris, which now includes tires and various concrete chunks of no historic value.

Detailed proposal.