Planting trees today to stem flooding tomorrow

In recent years, Port Washington city workers have gotten plenty of practice planting trees, not just along the city streets but in parks and in their own nursery.

Last week, they were joined by other staff members and members of the public to plant 100 trees and shrubs on the far west end of Larabee Street as the city worked to complete the first phase of its planned west-side flood mitigation measures.

It took the group of about 16 people less than two hours to complete the work, Public Works Director Rob Vanden Noven said, noting the city got lucky and picked one of the last warm fall days to do the job.

Those helping to plant the trees included a crew from Kleen Test, representatives of Johnson Nursery and Stantec, its engineering firm for the project, officials and one resident.

“I thought it was a great day,” Vanden Noven said. “We got a lot done — a lot of work that will reap big benefits in the future.”

The trees and shrubs, all native species, were planted upland from the dry retention pond the city recently built and are intended to not just beautify the area but to absorb groundwater and treat runoff, Vanden Noven said.

In spring, the city will also plant some wetland plant species to help absorb water, he noted.

“The goal is to have diverse, deep-rooted plants that will prevent erosion and treat the water,” he said. “Once it’s established, it should provide an outstanding habitat. It’s green infrastructure, and it’s going to look great.”

It will take about three years for the plantings to get established, Vanden Noven said, and Stantec will handle the work needed to get to that point.

“The establishment period is critical,” he said. “Once it’s established, it doesn’t require as much maintenance.”

As part of the project, the city rebuilt the former retention pond, which Vanden Noven said was “infested with non-native species.”

The city’s also improved the stormwater inlet capacity, placing new, larger catch basin grates in the streets and field inlets in the area to allow more water to get into the system during storms. 

The work done this year cost about $800,000, including the design and construction of the dry retention pond and establishing the plantings. 

Of that amount, $400,000 was paid with a Sustain the Great Lakes grant through the National Fish and Wildlife Foundation. Last week’s planting project was part of the grant requirement to provide public outreach, Vanden Noven said. 

The grant also seeks to encourage residents to plant rain gardens, and that may be done through next spring’s planting project or a separate event, he said. 

The additional plantings aren’t the only work being done for the flood mitigation project next year, Vanden Noven said.

Next year, the city will design larger box culverts for Spring Street and Garfield Avenue. These will not only increase the capacity of the stormwater system, they will also facilitate water movement.

“In a large storm event, there will still be water running on the surface,” he said. “But inlet capacity won’t be an issue. The water should flow through quickly.”

The project, he noted, has been designed to handle a 100-year storm.

The city will also be applying for grant money next year to help pay for this work, which Vanden Noven said he hopes to complete in 2023.