Protecting Roads From Rising Tides Could Cost Millions

by William F. Galvin
The Herring River has breached North Road several times in the past couple of months. WILLIAM F. GALVIN PHOTO The Herring River has breached North Road several times in the past couple of months. WILLIAM F. GALVIN PHOTO

HARWICH – Extreme weather, climate change, sea level rise and storm surges are impacting low-lying roads across the Cape. In Harwich, the intersection of Route 28 and Bay Road and North Road have been identified as top priorities for resiliency upgrades.

Potential solutions developed by the Cape Cod Commission and the Woods Hole Group (WHG) could cost up to $2 million, and may include bridges, culverts and other structures.

The commission and WHG have been working for well over two years on vulnerability assessments of roads in towns across the Cape. In Harwich,14 road segments were identified as locations where high tide flooding is considered a high risk and where conditions are likely to be exacerbated in future years. The Cape Cod Commission program focuses on providing conceptual design solutions for the two top priority road segments selected by the town.

The study projects sea level rises could be as high as 1.4 feet by 2030, 2.7 feet by 2050 and 4.5 feet by 2070, according to Joe Famely, climate and sustainability team leader with the WHG. He said by 2070, there is the potential in extreme weather conditions that 55 miles of road could possibly be flooded in town.

The town has identified Route 28 at Bay Road in East Harwich and North Road in West Harwich as priority roadways under the program. On Feb. 7 the commission and the Woods Hole Group conducted a virtual workshop reviewing three conceptual design alternatives for the Route 28 at Bay Road location and two alternatives for North Road. The concepts include raising the roads

Heather McElroy, natural resources program manager with the Cape Cod Commission, made it clear that the program would provide concept designs but the town would have to fund road improvements to North Road, and the Massachusetts Department of Transportation would be responsible for work on Route 28.

The elevation of Route 28 at Bay Road is 6.6 feet. According to the assessment, the chance of flooding annually without improvements is 100 percent. Three alternative designs were provided for the intersection. The first recommends 577 linear feet of the state-owned road be elevated to 9.5 feet with vegetated side slopes bolstered by steel sheets. There is a possibility of maintaining existing parking and access for the beach with ramps. The road would be raised 2.9 feet at its original low point. The estimated cost is $1,140,000.

The second alternative is placing approximately 600 linear feet of 48-inch temporary barriers on the bay side of the road before storms. A smaller flood wall to 10 feet cuts off a flanking flood pathway from Muddy Creek, according to the alternative. The estimated cost is $320,000

The third alternative calls for a dune restoration to 9.5 feet to protect the road from bayside flooding. Mobi-mats would be used to prevent dune erosion and improve accessibility. A small flood wall and berm to 9.5 feet would also prevent flanking flooding from Muddy Creek, according to the proposal. The estimated cost is $378,000.

Bruce Finley, owner of the home along Route 28 at the corner of Bay Road, said his property experienced major flooding during the Perfect Storm, and during a January storm in 2015 he had four-and-a-half feet of water in his basement. Flooding occurs when water comes across Route 28 at Bay Road, entering his property from the back side, he said.

He questioned the impact on access to his property by raising the road by nearly three feet. Linnea Laux, a climate resiliency specialist with WHG, said the road would only be raised a foot-and-a-half along the road incline on the north side of Finley’s property.

Finley also said in nor’easters waves come across Route 28 and end up on his lawn. He wanted to be sure dune restoration would be able to withstand the impact of the surf. Finley said he is willing to work with the group on a solution.

When the culvert was opened into Muddy Creek it relieved water pressure noticeably in the area. Finley added. He also commended the use of dredge material from the Round Cove channel to nourish Bay Road Beach as a means of containing storm surge.

Laux said the 2.6-foot elevation along a segment of North Road was the lowest WHG encountered in the project. Parts of the road just north of Smith Street are starting to erode, she said, and a second section of North Road just beyond where the dirt surface begins was also in need of addressing. That section of the road has an elevation of 2.9 feet, and by 2030 flooding could be expected frequently.

Alternative one for North Road calls for 1,360 linear feet of the town-owned road to be elevated to 6.7 feet with the traditional side slope and steel sheeting. It calls for a 40-foot bridge span at the western end of the road allowing salt marsh migration and protecting the road from erosion by the Herring River. The estimated cost was $2,030,000.

Laux said with this degree of raising of the road, access to the cottage on the east side, along the river, would be very difficult. The cottage would need to be relocated or razed, she said.

The other alternative, a hybrid approach, would require a road elevation to 4.8 feet using vegetated side slopes and sheet pile. A culvert would be installed at the low point in the road to allow salt marsh migration. The estimated cost is $1,440,000.

“Can you put a culvert in without raising the road short term?” inquired North Road resident Andrea Silbert, who is periodically stranded when tides place the road under water.

“You can’t stick a culvert in tomorrow,” Department of Public Works Director Lincoln Hooper said, because it will take time to get it permitted. “It’s three years out to do a culvert.”

“Without raising [the road] it would have very little benefit,” added Laux.

Laux said the bridge and culvert would create a new connection between the river and the marsh on the left side of the road and would require additional permitting. The wetlands on the left side of North Road are more of a freshwater marsh.

Hooper said all of the concepts are very preliminary, and the cost estimates appear to be well under estimates obtained by the town. He had a preliminary engineering cost estimate for North Road that was twice the projection provided in the alternatives.

“I don’t want you to think we are going to get a bridge for $2 million,” said Hooper. “The amount of permitting and time is mind boggling. It’s not an easy fix.”

Famely said further design work is likely to amplify the cost of the projects.

“Hopefully tying the marsh restoration to the project is a way of getting federal dollars,” said Hooper.

The next step, said Hooper, is to bring the projects to the select board. He made it clear there is no funding in place for them at this time.

McElroy said there are potential grant options to assist with funding. She identified the Natural Resources and Conservation Service, the Federal Infrastructure Bill, FEMA Building Resilience and Infrastructure and Communities program, Passage of Wildlife for Culvert Replacement program and state Division of Ecological Restoration Culvert Replacement Fund as possible sources.