COMMENTARY
Just replacing sand can't heal Maui's beaches

By Chip Fletcher
Professor of geology and geophysics at the University of Hawai'i at Manoa

Maui County is amending its coastal setback rules, consistent with its authority as defined by state coastal zone management law.

The health of Maui's tourism depends to a great extent on the health of its beaches, such as Ka'anapali's. In reality, the best beach management would combine strong planning with optimum engineering. Advertiser library photo • April 26, 2001

Additional benefits will include improved public access, a more scenic shoreline, reduced seawall construction leading to improved coastal water quality, and reduced homeowner insurance rates under the Federal Emergency Management Agency's community rating program, in which Maui is a participant.

The new rules follow guidelines from FEMA, two National Academy of Sciences reports, recommendations coming out of the state coastal zone management program and the state Department of Land and Natural Resources (source of the Hawai'i Coastal Erosion Management Plan), as well as the Maui Beach Management Plan adopted by the County Council in 1998. The new rules also are consistent with Maui community plans calling for increased beach protection and which specifically call for the use of erosion-rate based setbacks.

In a Dec. 30 editorial, The Advertiser wondered about the impact of the new setback on existing homes with regard to fire loss and other damage. Existing setback rules, state special management area laws and the county's participation in the national flood insurance program govern rebuilding within the setback area. Under existing law, if a legal structure is damaged in excess of 50 percent of its assessed value, there is no guarantee that the structure can be rebuilt in the exact same manner and location. The procedure for rebuilding is set forth in the governing statutes named above. This will not change. What will change is the location of the setback, which will be defined by erosion rate. Legal structures in high erosion hazard zones may find themselves governed by the existing statutes which are exercised through the discretionary authority of Maui County and the county Planning Commission.

The suggestion has been raised (Island Voices, Jan. 7) that we can manage our beaches through sand nourishment alone. Even in those communities and states (such as in Florida and the Carolinas) where beach nourishment is a common and preferred management alternative, strong setback and rebuilding restrictions are in place to protect beach and dune systems.

Successful beach management requires a combination of approaches to maintain planning flexibility, efficiency and maximum effectiveness. These include:

• Historical hazard analysis to determine high-hazard areas and avoid poor siting of buildings in these areas.

• Controlling proliferation of imprudently located buildings through guidelines that are implemented at every stage of land use — from initial zoning through redevelopment and rebuilding. These should emphasize road layout, building location, construction standards, and rebuilding.

• Willing-seller, coastal land acquisition programs to obtain vulnerable and high-hazard parcels, as well as lands with high ecological and community value, and remove these from development.

• Beach nourishment with and without the use of groins designed by experienced engineers, including analysis of erosion causes and potential solutions other than nourishment.

Although nourishment can be a highly useful and effective tool, it is unrealistic to believe or suggest that all beaches in Hawai'i with erosion problems can be managed or protected by beach nourishment alone. The principle problems:

• Despite high hopes, consultant studies of offshore sand sources indicate much of the material is not appropriate for beaches. Also, we lack suitable large-scale upland sand sources. However, many offshore sources and several promising upland sources have not yet been analyzed.

• The potential for real and perceived environmental, surfing and fishing impacts associated with offshore dredging and placement of beach sand has not been thoroughly explored.

• Nourishment has a high cost. Recent studies for the DLNR and Army Corps of Engineers indicate these costs are justified from an analysis of visitor economics in Waikiki. Nonetheless, where will the money come from, and who will pay for the many eroding beaches lacking Waikiki's strong tourism revenues?

Typically, one-time nourishment does not last long. Sand placement involves recurring projects and costs. The $12 million figure for beach restoration cited in the Island Voices article actually referred only to Waikiki Beach and perhaps a few additional sites on O'ahu, and did not consider the cost of project design, sand-source development, permits, or periodic renourishment in the future.

Despite these caveats, small-scale beach nourishment is alive and well in Hawai'i. On Maui, two homeowner groups are paying to place sand on beaches and working with agencies to obtain proper permits. Through the efforts of the DLNR and Corps of Engineers, and the state Marine and Coastal Zone Advisory Group (of which Maui County is a member) a new general permit may soon be available that streamlines the process for small, neighborhood-scale nourishment of qualified beaches.

Although large-scale nourishment is expensive, the expense may be justified in light of $10 billion in statewide annual tourism revenues, but it is important to be realistic about the challenges and costs.

What would it cost to restore Maui's beaches? Let's outline an optimistic scenario.

Dozens of miles of Maui shoreline are chronically eroding, and about four miles of beach have been completely lost to erosion. A typical island beach requires about 25 cubic yards of sand per foot of beach for a total of 528,000 cubic yards needed to restore four miles. Maui's already strained roadways would be horrendously clogged and damaged if this sand were delivered by truck. Although the necessary marine sand sources have not been identified, let's assume an appropriate marine sand field is found near every needful beach. Let's also assume that permits can be obtained (remember these are National Whale Sanctuary waters) to dredge and pump sand directly across the reefs onto the beach.

The expense of bringing in a hopper dredge from the Mainland is about $2 million; a portion of this expense can be bypassed if a local dredge is found (though none is known to exist). Sand delivered to the shore would cost about $20 per cubic yard, totaling about $13 million. Add to this about $2 million for consultant work to get the permits, draw up the construction plans, identify and develop the sand sources, and manage construction contracts. In about half the cases, the new sand will have to be stabilized with groins, for about $10 million, so it is not quickly lost to erosion. The total cost is about $25 million. Future costs to renourish some beaches over five to 10 years can be estimated at $5 million to $7 million. Let's call it $30 million in all.

From an economic perspective, $30 million would seem to be justified, given that 24 percent of total 2001 visitor days were spent on Maui and that beaches are a primary attraction. The renewed beaches might lead to a rise in property values, and accompanying tax receipts may repay private contributors and public sources. But keep in mind the many assumptions of this rosy scenario and the fact that dozens of miles of chronically eroding shoreline still lie unattended.

Nourishment is not realistically applicable to all of Hawai'i's beaches, and it is not a replacement for other effective coastal management policies, including prudent setbacks and rebuilding practices. But nourishment does have high potential, provided that costs and benefits are truthfully defined. In reality, the best beach management would combine strong planning tools (such as rational setbacks) with engineering tools (such as nourishment). It is entirely appropriate to have forward movement on both fronts — which, indeed, is the situation on Maui.