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Dewey’s stormwater management plan complete

41-project, 600-page document looks to help with bayside flooding
October 23, 2017

Story Location:
Read Avenue
Dewey Beach, DE 19971
United States

Read Avenue in Dewey may be getting all the love right now, but a recently completed, 600-plus-page stormwater management plan details a path forward to help reduce flooding throughout the southern half of town.

In spring 2016, town officials voted unanimously to spend $50,000 toward a $104,000 Surface Water Matching Planning Grant, created to improve water quality in the state’s impaired watersheds by supporting the planning, preliminary engineering and feasibility analysis of surface water improvement projects and activities.

Marianne Walch, Center for the Inland Bays science and restoration coordinator, laughed at the size of the cumbersome document with its 41 projects. It was a highly technical exercise with a lot of information about soil types and hydrologic modeling, she said.

“The understanding is that these projects won’t all be built at once, but the idea is that this document can be picked up years from now and understood by an engineer designing a specific project,” said Walch.

The plan took over a year to complete, and town officials have already begun work to check one project off the list. During the Sept. 8 meeting, council voted to spend up to $25,000 toward a $104,000 Community Water Quality Improvement Grant proposal to help pay for a bioretention area in front of the Little Store on the ocean block corner of Read Avenue and Route 1. Walch said she expects to hear in late October on the status of the grant.

In February, under the same water quality grant, town council unanimously approved contributing $35,000 toward a $175,000 bayside project on Read Avenue. The town received word in August it had received the grant, and it’s currently going through the permitting process.

The stormwater management plan accounts for an area with eight drainage basins from Saulsbury Street south to Collins Avenue. One basin has no proposed projects and a ninth basin includes a couple blocks of Indian Beach immediately south of Dewey.

The report takes the basins and breaks proposed projects down into four groups – bioretention areas, permeable pavers, pervious concrete and porous asphalt. Coming in at 17 projects each, most of the proposed flooding reduction comes in the form of bioretention areas and porous asphalt.

Except for two large areas proposed in the bayside parking lots on either side of the Hyatt, most of the porous asphalt projects involve repaving the parking area in front of properties on the ocean block, beginning with McKinley Avenue.

Walch said the ocean block was chosen for the porous asphalt because that’s where there’s enough ground underneath the pavement to soak up water. Closer to the bay, the ability of the soils to soak up water diminished greatly, she said.

Walch said the parking areas were chosen, instead of the streets too, because the load-bearing requirements for parking areas are less stringent than for streets.

There are six porous concrete projects in the plan, all of which involve replacing the concrete median that splits southbound and northbound Route 1.

The bioretention areas are small, scattered throughout the project area and mostly involve the corners of streets – similar to the proposed Read Avenue project.

Walch said there’s very little open space in Dewey, and the various grass islands chosen looked to be the most promising in reducing stormwater runoff.

The cost of the projects are in 20-year estimates, and they range from just over $100,000 to over $1 million. Generally, the bioretention areas are the cheapest, while the porous asphalt is the most expensive. There is one porous asphalt project on Bellevue Street that has a 20-year-estimate of about $78,000.

Walch said she recognizes some projects are cost prohibitive, but she said it’s a list that can easily be used by the town and, she said, they can peel them off one by one.

Dewey Beach Town Manager Marc Appelbaum said the partnership between the town and the center has worked well over the years because the town has the money to invest, and it recognizes something needs to be done.

“It’s good when everybody’s got skin in the game,” he said.

The stormwater management plan is available on the town’s website at townofdeweybeach.com.

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