2009-06-04 / Front Page

CRMC recommends changes to building height requirements

By Tyler Will

The increase in geographic temperatures and the rise of historic sea levels are two factors influencing proposed, voluntary changes of building heights above wave crests in the state's coastal management program.

While the changes are voluntary and relate to flooding, Boyd said the changes are not considered critical.

"Sea level is expected to rise three feet over the end of the century, not next week, so it is not urgent," he said. "Nevertheless, we want folks to be thinking about the consequences of building along the coast line."

Proposed amendments to Section 145 of the Rhode Island Coastal Resources Management Program would encourage residents and businesses with property near the water to build their assets higher off the surface of the ocean. The document, from the Rhode Island Coastal Resources Management Council, said wave crest heights will increase because of rising sea levels, and ocean-side properties will be at greater risk of flood.

The former standards set building bottoms at .7 inches off the surface of the water, but another benchmark height will put buildings at .9 inches off the surface of the water, according to the report.

The document is available on- line at www.crmc.ri.gov.

RICRMC Coastal Policy Analyst James Boyd said Section 145 was adopted in January 2008, but a small group of environmental offi cials met to align state flood zone policies and standards

Though modest, changes in the text increased the rate of sea level rise over the last century. The original document said the rate of change was 10.1 inches, plus or minus 1.2 inches; to 10.2 inches, plus or minus .75 inches.

Boyd said the reason for the change was simply that it had been updated, and was more accurate.

Other changes based findings of the report more on local and regional evidence, and less global evidence.

"We have reviewed local tide gauges and local observations by local scientists," Boyd said in a e-mail. The report also said some sea level change is due to tectonic plate movement due to ice, and also removal of sediment or oil.

A diagram in the report illustrates the concept behind the changes, with a picture of a building close to the surface of the water, and a second picture of a building higher off the water, which provides a buffer allowance for rising sea levels.

A graph shows that the current sea level is only about .1 inch below ocean-side building bottoms. However, the same graph shows that sea level was above oceanside building bottoms in the late 1990s and during 2003 to 2005.

Further changes make explanations of terms and findings more specific, and tweak the language of the report to make it clearer.

The data was taken in Newport because Boyd said the tide gauge there is the oldest and most continuously used of the five in Rhode Island waters. The gauge has been used since 1930, Boyd said, and indicates sea levels in Newport have risen 8 inches since 1930.

The changes will require the formal rulemaking process for government agencies, which requires a 30-day public notice and a public hearing, which has not been scheduled yet. Boyd said RICRMC also plans to hold scientific panels and workshops for information, which also have not been scheduled yet.

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