Million-dollar solution to restore eroding beach

Sandbags were placed in front of the South Bay Beach Club to try to keep the sea from encroaching on the eroding sandy beach in November 2019. - Photo: Courtesy of DoE

A $1.25 million government-led ‘beach nourishment’ project has been proposed to counter erosion at the southern end of Seven Mile Beach.

The proposal, endorsed by the Department of Environment, has been suggested as an alternative to a project put forward by the Grand Cayman Marriott Beach Resort to rebuild its disappearing beach. The hotelier says it is losing millions of dollars in revenue because seasonal erosion reduces its beachfront to a sliver of sand.

The DoE and its consultants Olsen Associates dismissed the Marriott’s complex proposal, which involved a system of sand-filled mattresses and ‘geotubes’, as unsightly and unworkable and has urged Cabinet to reject it.

Instead, they advise a beach-nourishment programme along a 1,000-foot stretch of coastline fronting the Marriott, Tamarind Bay, Regal Beach Club and South Bay Beach Club.
Wendy Johnston, of the DoE’s technical review committee, said this measure would involve depositing a large amount of sand – around 12,000 cubic yards – along the shoreline.

She said it was a “short-to-medium-term” solution that should restore a viable beach in the area. But she warned erosion on this scale is a consequence of development too close to the shoreline and is likely to get worse as sea-level rise impacts Grand Cayman in the coming decades.

The beach area in front of the Marriott resort in October last year. – Photo: Courtesy of DoE

The long-term recommendation is to move infrastructure off the active beach.

“There is a process called managed retreat, which some countries, including Hawaii, have adopted to start removing and repositioning hard structures off the active beach,” she said.

“In the long term, there are limited options to hold back the sea against development positioned too close to the water. Beaches advance and retreat naturally and we need to give them enough room to flex through the use of appropriate development setbacks.”

That approach is endorsed in a consultant’s report, published Wednesday as an appendix to the DoE’s technical review of the Marriott application.

It states, “The other parallel, reliable solution is selected local strategic retreat. Any opportunity to remove at least parts of an existing seawall to create additional upland for the beach is a means to create reliable beach recreation area and guests’ wading entry to the sea.”

The Marriott’s pool and some other structures are currently built on the active beach.

The report, by coastal engineers Olsen Associates, acknowledges that the hotel and adjacent properties are “experiencing both current and long-term seasonally acute beach erosion problems, and that a ‘do-nothing’ approach” is not sustainable.

It recommends using 12,000 cubic yards of beach-quality sand – enough to fill four Olympic-size swimming pools – for a beach-nourishment project alongside the Marriott and an additional stretch of shoreline, spanning 1,000 feet in total.

This would achieve a beach-width advancement of 50 feet at mid-tide level and leave at least 15 feet of dry beach at all times, the consultants predict.

The sand could be sourced from the Bahamas, for example, at a total cost of US$1.5 million, the report notes.

It is not clear how this would be funded and the DoE report of 26 Nov. 2019 indicates that advancing the project will require urgent discussions between the ministries of planning and environment, which have not yet occurred.

The Olsen Associates report notes the costs could be split among the property owners.

“Apportioned among the four resort properties along 1,000 feet of shorefront, the individual cost may be on the order of between $300K and $450K per property, by shorefront length, without subsidy,” the report said.

Compiled by the company’s president Kevin Bodge, the report is unequivocal in its recommendation that the Marriott’s proposal be rejected.

“In my experience, misappropriate beach management, such as unaesthetic geotubes-mattresses and/or an over-eroded beach, has far-reaching consequences to the Cayman Islands beyond just the subject property,” he wrote.

“Guests’ perception of an ugly, absent, or unusable sand beach along one major property quickly spreads like a cancer to the remainder of the beachfront, warranted or not.”

He added that something should be done to address the issue in an aesthetically pleasing way.

“The reputation of Seven Mile Beach as a whole can become rapidly tarnished by the lack of beach at a few discrete properties along SMB. Accordingly, prudent action to ensure the value and attractiveness of the beach along any few single properties along SMB is of great overall value to all of the properties along SMB and the Cayman Islands in general.”

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3 COMMENTS

  1. I believe similar problems have occurred along sections of Miami beach and elsewhere on the southeast coast which were also addressed by “beach nourishment”. Perhaps we could seek advice from the authorities there.

  2. I notice that Plantation Village is not listed. It is the worst of all the properties listed above. It is usually impossible to walk around their wall. Even now when some sand has returned and you can walk on sand on all 4 of the above named properties you still have to walk in water and on algae to get around their property. This plan will not work if Plantation Village is not included

  3. See my letter to the Editor on 3 Oct, 2019 in which I warn of the potential for the proposed dredging of the harbour to speed up this sand loss process at the south end of SMB. I also point out that we have grossly over-fished our main source of new sand… and desperately need to protect and restore our decimated populations of the three largest species of parrotfish. Building energy reflectors too close to the water was an obvious mistake that was well understood long before we allowed it to happen here. Moving back off the beach or up onto stilts is the only long term solution I know of for these beleaguered properties. Tough choices to make. And it’s all for naught if you don’t move far enough back. Feeling sincere commiseration, Californians would say “downer, man”.