The sand allegedly was finer than the original sand and contained excess silt that enveloped coral, smothering it and killing the small animals that lived in and around it. As in other projects, on-shore sand availability was limited, forcing consideration of more expensive offshore sources. A second project, along Stable Road, that attempted to slow rather than halt erosion, was stopped halfway toward its goal of adding of sand. The beaches had been retreating at a "comparatively fast rate" for half a century. The restoration was complicated by the presence of old seawalls, groins, piles of rocks and other structures. This project used sand-filled geotextile tube groins that were originally to remain in place for up to 3 years. A pipe was to transport sand from deeper water to the beach. The pipe was anchored by concrete blocks attached by fibre straps. A video showed the blocks bouncing off the coral in the current, killing whatever they touched. In places the straps broke, allowing the pipe to move across the reef, "planing it down". Bad weather exacerbated the damaging movement and killed the project. The smooth, cylindrical geotextile tubes could be difficult to climb over before they were covered by sand. Supporters claimed that 2010's seasonal summer erosion was less than in prior years, although the beach was narrower after the restoration ended than in 2008. Authorities were studying whether to require the project to remove the groins immediately. Potential alternatives to geotextile tubes for moving sand included floating dredges and/or trucking in sand dredged offshore. A final consideration was sea level rise and that Maui was sinking under its own weight. Both Maui and Hawaii Island surround massive mountains (Haleakala, Mauna Loa, and Mauna Kea) and were expanding a giant dimple in the ocean floor, some below the mountain summits. The Outer Banks The Outer Banks off the coast of North Carolina and southeastern Virginia include a number of towns. Five of the six town have undergone beach nourishment since 2011. The projects were as follows: Duck, North Carolina: the beach nourishment took place in 2017 and cost an estimated $14,057,929. Southern Shores, North Carolina - the estimated costs for the Southern Shores project was approximately $950,000 and was completed in 2017. There is a proposed additional project to widen the beaches in 2022 with an estimated cost of between $9 million and $13.5 million. Kitty Hawk, North Carolina