Erosion Endangers $20M Morris Island Property; Emergency Order OK’d To Stem The Tide

by Tim Wood
The remnants of South Beach, seen at the bottom of this photo, are squeezing the navigation channel against Morris Island, destroying part of the revetment that protects four properties along the shoreline. SPENCER KENNARD PHOTO
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CHATHAM – There are a lot of mysteries in nature. The latest: what happened to the revetment protecting the $20 million house at 97 Tilipi Run?

“It’s gone,” said Coastal Resources Director Ted Keon. “It has fallen into the hole.”

The “hole” is a deep channel being pushed against the southwest corner of Morris Island where the revetment was previously located. Keon said he’s seen failed revetments before, but he’s “never seen it where it’s literally disappeared.”

On Jan. 24, the conservation commission approved an emergency order allowing installation of 60-foot steel sheeting along more than 200 feet of waterfront at 97 Tilipi Run to try to stem the erosion that swallowed the rock wall that was originally built in 1998.

Erosion has been ravaging the Morris Island coast for several years, carving more than 100 feet from the bluff at the Monomoy National Wildlife Refuge headquarters property. Two major buildings were removed as erosion encroached, and the final structure, the visitors center and office, is slated for demolition in April.

The four properties west of the refuge headquarters are protected by rock revetments. Last year, steel sheeting was installed at the Shalom property, immediately west of the refuge land, to prevent erosion from going around the existing revetment. The conservation commission also approved an increase in height of the revetment that protects the four homes from the Shalom property to 97 Tilipi Run, which is owned by TR 97 Nominee Trust.

The four waterfront homes along Tilipi Run have a collective assessed value of $51.8 million. The 7,465-square-foot home at 97 Tilipi Run, built in 2006, was purchased in 2018 for $14,750,000. The town’s assessing department currently values the property at $20.8 million.

The 2017 Fool’s Cut, which broke through the barrier beach east of Morris Island, caused the breakup of South Beach, the remnants of which moved to the west, between Morris and Monomoy islands. As the northern lobe of the former barrier beach moves toward Morris Island like a pincer, it is squeezing the channel up against the shore. The rapid tidal flow — geologists say it is almost like a river, flowing east to west from the Atlantic to Nantucket Sound, which is lower than the ocean — has scoured out a channel as deep as 40 feet, which undermined the revetment, Keon said. Within a six-month period, the revetment began to settle, partially failed and then completely failed “in a very rapid fashion,” he said.

Failure of the revetment has left the coastal bank at 97 Tilipi Run exposed to open ocean waves, which has caused rapid erosion and is endangering the pool and house beyond it, Keon wrote in a memo to the conservation commission in support of the emergency order. Large trees have toppled down the bank and were swept into the harbor and are “a significant navigation and public safety hazard,” he wrote.

“Potential loss of the residential structure will similarly introduce debris and potentially hazardous material into the harbor,” Keon’s memo reads. According to the conservation commission filing, the pool is 6 feet from the top of the bank while the house, at its closest point, is 70 feet from the edge.

It’s anticipated that the shoals that are squeezing the channel will eventually migrate south and west, Keon said. “We have been watching that,” he said. “Frankly I’d hoped it would move south more quickly. It hasn’t done that.” Movement of the sand will lessen the scouring, but could be a problem for the land immediately to the west, which is owned by the U.S. Fish and Wildlife Service. There are large trees on that property that could also get swept into the channel and pose a hazard to boats.

“They have no funding to deal with it, in all honesty,” Keon said of the federal agency.

The town is currently pursuing permits to install flow structures just offshore south of the current erosion hotspot, closer to Crescent Beach. The structures would not likely impact the erosion, Keon said, but the dynamics of the area will also probably change by the time the structures are installed.

The steel sheets will extend slightly onto the property at 75 Tilipi Run landward of the existing revetment, said Catherine Ricks, project manager for engineers Tighe and Bond or Orleans. The bulkhead will taper down to existing ground level to the west. Plans call for placing rocks at the base of the bulkhead; there currently isn’t enough of a base to support a full revetment. The stones will help break up the rapid flow of the channel and deflect waves, according to the project description.

The Cape Cod Commission’s planning and regulations committee approved the modification of the original 1998 revetment permit on Jan. 25 allowing the emergency work. According to Conservation Agent Paul Wightman, the conservation commission will issue the final emergency certification once a contractor is hired and the work is ready to begin; at that point the work to abate the emergency must be finished within 30 days. A full notice of intent must filed within 21 days, which Ricks said would include additional revetment work as well as “soft” erosion control measures for the west end of the 97 Tilipi Run property, which is a coastal beach where “hard” structures like revetments are not allowed. A state permit will also be required for the final structure, since it will be below high water.

At the Jan. 24 hearing, commission members were concerned that installation of the steel sheets — which are vibrated into the ground — could damage the pool or house foundation. That happened at the Shalom property at 27 Tilipi Run, where the foundation of a guest house cracked in several places during installation of steel sheets. It would be a “real problem to a catastrophe on that bank if the pool collapses,” said chair Janet Williams.

Ricks said the work would be monitored closely and stopped if that happens, although there’s no expectation that cracking will occur given the distance between the house and pool and the spot where the steel will be driven into the ground.

There’s inherent risk in this type of project, Williams said. “It comes fraught with risks for both doing nothing and for moving ahead with this emergency project,” she said. “We just have to be mindful of what those risks are.”

This isn’t the first emergency order issued by the commission attributable to the town’s dynamic coastline, Williams said, and won’t be the last.

“This is what we’re looking at as the new normal for our increasingly vulnerable coastline,” she said. A larger conversation needs to happen about the risks facing the coast and the options for assessing and dealing with them, she said.

“It’s vital to this community, and it’s not really up to a small group of citizen volunteers to continue to make decisions on a case-by-case basis, property-by-property basis,” said Williams. “That’s not a sustainable way of dealing with a problem that is community wide.”