Hospital site risks assessed and found acceptable
By Dan Cabot - December 28, 2006
In the year just past, the Martha's Vineyard Commission (MVC) questioned the decision of Martha's Vineyard Hospital officials to rebuild on the current Eastville site on Beach Road. The MVC was concerned about the risks of damage from coastal storms to a lot only 610 feet (at its closest) from Vineyard Haven harbor.
When considering an important action (such as the hospital plan to rebuild at the beach road site), planners often ask, "What could go wrong?" Because not everything that could go wrong is equally likely to go wrong, and some risks can be minimized by careful planning, those responsible must evaluate all risks before making a final plan.
Hospital officials replied to the MVC that the building architects, Thomas, Miller and Partners, were very familiar with designing hospitals in areas subject to major coastal storms and had taken those risks into account. However, in an effort to reassure the MVC that the risks of the site are acceptable, last summer the hospital agreed to a risk assessment study, if it would not lead to significant time delays in the permitting process.
Wicked northeast storms, such as the one that put this schooner ashore, as well as hurricanes pound on the north facing shore, which the Martha's Vineyard Hospital overlooks. MV Times file photo
The MVC chose as consultants the Woods Hole Group (WHG), which specializes in marine science and engineering, shoreline protection and management, and environmental assessment and remediation. The hospital board agreed to pay $24,000 for the study.
The 61-page risk assessment did not figure large in the public hearings. The final report concluded that the hospital's risks were acceptable, and on Dec. 7 the MVC voted to approve the hospital plan.
Click here to view the full report.
What are the risks?
The final assessment was presented by the WHG in October. An exhaustive study, it considered risks to the buildings themselves and risks to infrastructure which might interrupt critical hospital services.
Many risks are Island-wide, such as hurricane winds; interruption of electrical, water, or sewage lines; wildfire; snowstorms; and even earthquake. Such risk must be dealt with no matter where the hospital is located.
Vulnerability to high winds (a high probability) and earthquake (a very low probability) can be avoided by appropriate building standards, already included in the hospital's plans. The hospital has generators to take over for interrupted electrical service, and has redundant water supplies from both Vineyard Haven and Oak Bluffs.
In its report, the WHG dismissed the threat of wildfire, noting, "Significant wildfire events have not been reported for Martha's Vineyard." Critics of the report might note the great fire in Vineyard Haven in 1883 and several significant fires in the Correllus State Forest. However, such objections are probably not relevant to the hospital site, which is neither forested nor in a downtown location.
Three risks are specific to the hospital's Eastville location and received extensive coverage in the WHG's report: storm surge from hurricanes and northeasters, coastal erosion, and the possibility of a rise in sea level caused by global warming.
Storm surge
The WHG studied the history of storms in the area of the Vineyard between 1850 and 2006, including many damaging hurricanes and northeasters, such as "The Perfect Storm" of 1991. Of 536 storms, only three produced significant storm surge in Vineyard Haven harbor: the hurricane of 1938 (5.2 feet), the hurricane of 1944 (6.6 feet), and hurricane Carol of 1954 (7.2 feet). All were category 3 hurricanes when they reached the Vineyard. No category 4 or 5 hurricane has ever been recorded in New England.
It seems intuitive that storm surge from northeasters would be a problem for Vineyard Haven harbor because the funnel-shaped harbor faces the northeast. Nevertheless, no northeast storm has ever produced significant storm surge there. The WHG explains that the shallowness of Nantucket Sound and the barrier effect of Cape Cod offset the potential effects of wind directly into the harbor mouth.
While storm surges from the 1938, 1944, and 1954 hurricanes might have reached the base of the proposed hospital buildings, none would have threatened to overwhelm them. The WHG concludes that although damage from a category 3 hurricane is the greatest hazard the hospital faces, it is not a major threat to hospital buildings. A category 4 or 5 hurricane would be much more damaging, but WHG concluded they are unlikely to occur in New England.
While storm surge from a hurricane might temporarily close Beach Road and disrupt hospital operations in other ways, the WHG concludes, "Losses in functional capacity [from storm surge] should be temporary and should not endanger the patients or hospital staff."
To meet the threat of storm surge, the WHG suggested only minor changes in the hospital's rebuilding plans: to raise the proposed location of the emergency generator from 12 to 14.6 feet above sea level, and to redesign access roads and parking lots.
Shoreline erosion and
global warming
The WHG report concludes that shoreline erosion combined with a rise in sea level might, by the end of this century, move the coastline landward from its present location to a position about equal to the present landward edge of the beach, if no new man-made barriers are created. This would have the effect of also moving the flood plain inland toward the hospital site in case of a hurricane, but not far enough to change the report's conclusions.
Along the Vineyard Haven harbor coastline closest to the hospital, rates or erosion between 1897 and 1994 were about a half a foot per year.
As to rising sea levels, the WHG report comments, "The topic of accelerated worldwide sea level rise in the 21st century and beyond has been the subject of much scientific and political debate. . . . As of 2001, the estimated range of sea-level rise worldwide, for the period 1990 to 2100, was 0.29 to 2.9 feet."
Taking these two risks together, the WHG suggests that the hospital and the town of Oak Bluffs could mitigate any possible risk to the operation of the hospital by redesigning access roads and parking lots to create barriers to the sea. However, these risks are not scary enough, the WHG concludes, to put the hospital somewhere else on the Island.
In its summary, the WHG reports that most states have hospitals in places prone to flooding from storm surge, and Massachusetts ranks in the upper third in terms of the number of facilities in risk areas. Nevertheless, the WHG concludes, "Even though many of these hospitals are located in southern coastal states, where high intensity hurricanes have historically occurred, records of hospital damages from flooding and storm surge are not common. This brief comparison . . . supports the finding of low risk associated with the Martha's Vineyard Hospital development project."
