Flood Proofing Morris Island Road Could Cost Millions And May Not Even Work, Some Warn

CHATHAM – It could cost millions to protect Morris Island Road from flood waters caused by rising sea levels, and even raising the roadway surface and building up the nearby coastline may not prevent neighborhood residents from being stranded during storms. Other more drastic solutions — such as cutting an access road through wetlands or establishing a ferry to Morris and Stage islands — may have to be considered.

“I do not see a positive impact from any one of these alternatives,” Little Beach property owner Peter Chipman said of the options for protecting Morris Island Road presented last week by representatives of the Cape Cod Commission and Woods Hole Group.

As part of the commission’s low-lying roads project, two roadways were chosen in each Cape town to develop alternatives for protection against anticipated increases in flooding and storms due to climate change. After evaluating a number of possibilities, Chatham town staff settled on examining ways to protect sections of Morris Island Road and Ridgevale Road where flooding could strand residents of several neighborhoods.

For the two small segments along Ridgevale Road — 844 and 415 feet respectively — located just before the beach parking lot, two alternatives were proposed. The first alternative would elevate the road approximately three feet with vegetated side slopes and sheet steel in some spots to help hold the banking in place. Under this scenario, which carries an estimated price tag of $1,660,000, there would be a 10 percent chance of flooding at least once a year by 2030, a 20 percent chance by 2050 and a 100 percent chance by 2070.

The second alternative for Ridgevale Road would also involve raising the road level by about five feet, increase the size of an existing culvert that residents say has failed, and add a 250-foot wall on the eastern side of the road. At $1,440,000, this option would have the same probability of flooding as the first alternative.

Morris Island Road is more problematic, however, and three alternatives were proposed for protecting it from future flooding. The 2,474-foot-long segment studied runs from the intersection with Main Street to the culvert and currently inoperable tide gate, where the road height rises somewhat. It includes the intersection with Little Beach Road, where significant flooding has occurred fairly regularly, sometimes stranding vehicles and cutting off access to Little Beach and Morris and Stage islands.

“It’s a pretty complex location, pretty low-lying and vulnerable to flooding,” said Linnea Laux of the Woods Hole Group.

The location is subject to flooding from two sides: Stage Harbor to the west and Chatham Harbor to the east. Stage Harbor waters flow in through the culvert and adjacent wetlands, and the harbor waters come over low dunes as well as up the boat ramp at nearby Outermost Harbor Marine. The intersection is very low, at an elevation of 3.5 feet, said Laux; the road rises to about 5.1 feet as it passes by wetlands and up to nine feet at the culvert.

The first alternative is to elevate the road to 6.6 feet with vegetated slopes and extensive steel sheeting due to the wetlands, while upgrading the two existing culverts. The estimated cost is $3,770,000 but would only provide limited flood protection. Through 2030 there is a 20 percent chance of flooding with a 100 percent chance of flooding by 2050 and beyond.

Alternative two would raise the road higher — to 8.8 feet — and add dunes, seawalls and bulkheads on the harbor side as well as raising the bulkhead at Outermost Marine while replacing the aging culverts and tide gate. Similar recommendations were made during a previous town study of the area, Laux said. The cost would be $3 million and would provide flood protection through 2070.

Alternative three would use a combination of upgraded dunes and concrete “knee walls” to help raise the level of the road to 7.1 feet, but would involve no work at Outermost Marine. It would cost $743,000 but would only provide flood protection through 2050.

Because of the challenging location, the consultants wanted to try to look at creative solutions, Laux said. One idea was to run an access road through a conservation area connecting Little Beach to the higher section of Morris Island Road near the causeway. This would cost about $300,000 to build, but since it would go through deed-restricted conservation area, the legal costs involved in permitting would be more than the construction cost, she said. Another possibility was to provide a ferry to access Morris and Stage islands via a federal government landing on the Stage Harbor shore of Stage Island.

She said the alternatives were developed with the possibility of “mixing and matching” details. They also depend on cooperation from the private marina owners. There could also be significant impact to some private homes along the road which are in lower elevations.

The proposals would likely funnel stormwater water onto the private roads in the Little Beach neighborhood, said Chipman. With stormwater coming through the marina and Stage Harbor, “what you’re doing is dumping all from the condos to the intersection of Windmill Lane, Little Beach Road and Morris Island Road,” he said. He questioned whether that would create legal issues.

“Basically you’re sinking us into water,” he said.

The proposals might not solve the problem completely, but may reduce the risk of neighborhoods being cutoff during regular storms in the future, said Joseph Famely of the Woods Hole Group. “In smaller storms you may have drier roads,” he said.

That doesn’t mean the town could not consider work involving the private roads, said Director of Natural Resources Greg Berman. “Methods we used in the past may not be viable in the future. We have to look at alternatives that are outside the box,” he said.

The conceptual designs presented last week will be examined by town staff, who will get community input before choosing an alternative, said Coastal Resources Director Ted Keon. “There’s going to be a lot of public discussion on this,” he said.

It will be up to the town to hire engineers to develop more detailed plans and permitting, said Heather McElroy, natural resources program manager with the Cape Cod Commission. Financing will also be the town’s responsibility.

“There’s a lot more work that really needs to go into coming up with a viable approach to a solution,” she said.