History

Dewatering

SBPF initially installed a dewatering system in three locations in the 1990s: one in front of Codfish Park and two south of the Sankaty Head Lighthouse. This approach, which has been successful in the Netherlands and some other locations, intended to lower the water table at the edge of the surf zone, thereby attracting sand and building up the beach.

The system consisted of an underground pumping station connected to piping that runs along the beach. The results were mixed at best. The two installations south of the lighthouse never produced positive results, in part due to difficulties with keeping the pumping system functional.

The Codfish Park system achieved positive results. In one segment, when pumping occurred at many times its designed rate, the beach built out by over 100 feet. Some believed this was mere coincidence; others were convinced that it was caused by the success of the dewatering system. No one can be sure, but the Codfish Park beach was dramatically widened.

The dewatering effort has since been suspended and pumping stations and piping in the Sankaty areas removed. Because of the increased beach width, the Codfish Park system remains turned off

Sand-filled jute terraces

SBPF later received permits from the Town of Nantucket (the shoreline along the bluff is town-owned) for the installation of a sand-based terracing system. This was placed at the toe of the bluff in locations where adjacent homeowners agreed to pay the costs of installation and maintenance. Some of these terraces have now been in use for five years or more. Up to seven homes have participated at various times.

These terraces are now made of very large biodegradable, jute envelopes that are anchored to the bluff. Since the sand inside of them washes away usually multiple times per year, the envelopes are re-filled after major storms, thereby adding sand to the natural system of sand movement.

The current system is a vast improvement over the first sand bag system. Initially, this effort used small sand bags, usually held in place by 4″ x 4″ wooden posts. That setup experienced many failures during major storms, when many bags and posts washed into the ocean. Sometimes the bags washed up on other beaches north and south of Sankaty, creating possible harm to boats or swimmers in the area.

Although SBPF worked hard to clean up reported loose sand bags and posts, the public remains skeptical of the system because of the debris it created early on. Today, no posts are used in the system, and no jute bags have washed away in over three years. The effectiveness of protection provided by these terraces is limited, and is not expected to stand up to once in 25-50-year storms or larger. The cost of constantly re-filling the envelopes with sand is considered to be economically unsustainable. Some homeowners continue to use this method to protect their property until a more long-term solution can be found.