Archives: Spring 2002 Table of Contents
The Challenges of Managing an Evolving Shoreline
by Tracey Crago, WHOI Sea Grant

The Massachusetts shoreline spans 1,500 miles, with beaches covering nearly two-thirds of that distance. The changing nature of that coastline poses a challenge to all who enjoy it: recreational users, waterfront property owners, regulators, lawmakers, and those who derive their livelihoods from the sea. In a perfect world, the entire shoreline would be managed as one. In reality, the shoreline is segmented by many boundaries—property lines, town lines, state lines, coastal landform features—all presenting management challenges and inconsistencies.

Given those challenges, how are we doing when it comes to managing the Massachusetts shoreline? WHOI Sea Grant, through its coastal processes program, decided to investigate. Graham Giese, coastal geologist, and former Sea Grant extension agent, began by looking at outer or open ocean shorelines, sheltered shorelines (bays and estuaries), and developed shores. He considered the techniques used for managing each type of shoreline—and their effectiveness—
to get a sense of our progress.

Non-structural erosion control alternatives range from simple plantings to complex scenarios like that pictured here, involving the re-grading of a coastal bank, addition of fill material, a covering of biodegradable netting and coir logs—all blanketed with coastal plants. Photo credit: Jim O'Connell, WHOI Sea Grant.

Giese found that the management techniques used for different types of shorelines were not necessarily the same. Jim O’Connell, now coastal processes specialist for WHOI Sea Grant, picked up the project after Giese retired. During a 1997 workshop titled "Coastal Landform Management in Massachusetts," participants were asked to consider the state’s successes and failures in sustaining the beneficial functions of coastal landforms. The result? "Qualitatively, we are doing a decent job of trying to maintain a delicate balance of preserving landforms for future generations while allowing property owners ‘reasonable uses’ of their private property," explains O’Connell.

That workshop, he says, led to the coastal landform sustainability project, which set out to quantify opinions of the ‘how are we doing’ question by analyzing actual orders of conditions (permits) granted at the town level. The study documented permitted activities that took place on and adjacent to coastal landforms, and their potential effects on coastal landform function. All 15 towns on Cape Cod were involved in the one-year project, in which 319 projects involving 56 separate activities were reviewed and ‘rated’ in a sustainability rubric developed by Giese and carried out by personnel from the parti-cipating towns, with assistance from WHOI Sea Grant.

"Based on that 1999 exercise, we concluded that we are not maintaining the beneficial functions of coastal landforms," says O’Connell. "While science should be the underpinning of all coastal management, tradeoffs and balances are often necessary when applying performance standard-based regulations that govern activities on coastal landforms." Thus the second WHOI Sea Grant workshop, held in 2001: "Can Humans and Coastal Landforms Co-exist?"

Aimed at individuals actively engaged in planning, managing, regulating, engineering, education, and scientifically investigating coastal landforms and their beneficial functions, the workshop had a very applied focus. Attendees looked at case studies documenting the interactions between coastal landform functions and human activities. Analyses of the effects of activities and comparisons of alternative construction practices were also provided through an interactive dialogue.

"What became obvious," says O’Connell, "is that we possess a reasonably thorough qualitative understanding of the critical characteristics and beneficial functions of coastal landforms; however, our quantitative understanding and predictive capability to determine the effects of human activities on coastal landform function on a lot-by-lot basis is still evolving."

A third workshop, held in March 2002, began from the reality that management involves both science and human values. Titled "Stabilizing Dunes and Coastal Banks Using Vegetation and Bioengineering," the workshop had a practical focus, posing the following questions to speakers and participants: are there ways to improve coastal landform management in Massachusetts? Is there a middle ground? Do bioengineering and the use of coastal plants, as erosion control measures, work? What are the economics of bioengineering and plant control? By the end of the day, participants had learned about bio- and photodegradable materials, their aesthetic and functional values, and the use of native plants for coastal stabilization in a variety of scenarios. The general conclusion, says O’Connell, is that these measures "won’t stop erosion, but they can slow it in certain areas. The caution," says O’Connell, "is that in slowing erosion, adverse impacts will continue—loss of material for beaches and saltmarshes, for example—but such measures represent a good compromise."

O’Connell believes that such non-structural alternatives are becoming the accepted norm for planning and regulatory purposes. From a cost standpoint, bioengineering and vegetative alternatives, or a combination of both, are less expensive or comparable to ‘hard’ alternatives (groins, jetties, armoring techniques). What remains to be seen is the long-term viability of bioengineering projects, and the amount, frequency, and associated cost of maintenance for each scenario.

WHOI Sea Grant and the U.S. Geological Survey recently completed a study for Massachusetts Coastal Zone Management to update, map, and analyze historical shoreline changes in Massachusetts using GIS, aerial photographs, and historic shoreline data. The maps, along with a user guide, will soon be released by MCZM to assist towns in planning purposes. "All shorelines exhibit trend reversals—an erosion phase followed by an accretion phase and vice versa—because no shoreline is truly stable," explains O’Connell. "These maps are based on four to five snapshots over a 150-year period. A lot can happen in between that may not be captured by the maps."

That is where the user’s guide will be of greatest value, says O’Connell. "Extreme caution should be used when using long-term shoreline change data." The maps and accompanying data, he says, "have the potential to improve decisions about coastal management, residential and commercial development, and coastal research, by making the shoreline data comprehensible."

For more information about the shoreline change maps, user’s guides, or any of the WHOI Sea Grant workshops described here, contact Jim O’Connell at joconnell@whoi.edu or by calling (508) 289-2993.

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