Waves of concern

The changes are the result of a Federal Emergency Management Agency project to remap flood zones, county by county nationwide. The agency plans to finish most of its Massachusetts maps by next summer, and local governments are in the process of notifying residents and business owners about the new zoning. At the same time, lenders are telling affected borrowers they must increase their insurance coverage.

Property owners across the state, confused and upset about the zoning changes, are calling local officials to complain and seek more information. FEMA designates a property as being in a flood area if historical data show it has a 1 percent or greater chance of flooding during any given year.

Michael Nakagawa, whose home is one of about 125 in Cambridge’s Alewife section recently included in a flood plain, is organizing neighbors to challenge the new zoning.

“We shouldn’t be forced to pay higher insurance rates and face lower property values because of the inaccuracies of their study,’’ said Nakagawa, who lives near Alewife Brook. He hopes a surveyor can prove his home is safe from flooding because it is protected by an elevated sidewalk.

Catherine Daly Woodbury, storm water coordinator for the City of Cambridge, is sympathetic to the predicament of property owners, but just because a property hasn’t been under water before does not mean it can’t one day be flooded, she said.

“People are angry, and I try to point them in the right direction about where to get information for insurance and what their options are,’’ Woodbury said. “Flood insurance is very expensive.’’

FEMA’s effort to replace decades-old paper maps with digital versions started six years ago, said David Mendelsohn, who is coordinating the agency’s map modernization efforts in New England. Researchers are using new computer models and current topographical data to update maps drafted 20 or 30 years ago. As a result of improved technology, he said, areas susceptible to flooding at least once in a century can now be more precisely identified.

In addition, increased commercial and residential development is causing existing flood zones to be expanded, Mendelsohn said. Surfaces such as sidewalks and roadways can add to the risk of flooding during storms because they accelerate the flow of water.

FEMA defines a flood as a “condition where two or more acres of normally dry land or two more properties are inundated by water or mudflow.’’ The agency does not specify water levels.

Thousands of properties are also being located in new or expanded flood plains because of updated federal requirements related to dikes, dams, and hurricane barriers. FEMA is requiring local governments to certify that storm barriers will be effective, an engineering process that can be expensive and lengthy. Without such certification, FEMA will reclassify property adjacent to such barriers as being in a flood plain.

In Chicopee, about 5,000 properties will temporarily be in a flood plain because the city can’t immediately certify that a 7-mile riverfront levee system will protect them from floods, according to Mayor Michael Bissonnette. Before the levee system was built, the area was inundated with water during severe storms. Chicopee is working to repair and recertify the levees at a cost of more than $6 million, but the work won’t be finished before new maps are made effective this summer, he said.

“Nobody is in any danger,’’ said Bissonnette. “It was a typical federal bureaucratic reaction to the screw-up in New Orleans.’’

New Bedford must decide whether it can afford to recertify its hurricane barrier, a 3.5-mile-long steel and stone structure completed in 1966 to protect the city’s harbor. David Kennedy, the New Bedford planner director, said the city is wrestling with how to pay for engineering studies that could cost hundreds of thousands of dollars. “It’s an unfunded mandate and we hate those,’’ Kennedy said.

For property owners, it is crucial to find out about the zoning changes early. Those who act before the new maps are made effective - a date that varies by county - can qualify for steep discounts on additional insurance by being “grandfathered’’ into the National Flood Insurance Program, created in 1968 after most insurers stopped selling flood insurance.

The program is overseen by FEMA, and policies are made available through private insurers. Coverage can’t exceed $250,000 for property and $100,000 for contents. Because it’s a federal program, the basic policy remains the same from insurer to insurer, but premium prices vary depending on what is insured and the level of risk determined by FEMA. For example, it may cost more to insure a home perched at the ocean’s edge than one near a small stream.

Currently, about 50,000 Massachusetts properties are covered by National Flood Insurance Program policies. Flood insurance is mandatory if a property in a flood plain has a mortgage owned or guaranteed by federally backed entities, including lending giants Fannie Mae and Freddie Mac.

FEMA started designing new Massachusetts maps several years ago. As work in each county is completed, the agency produces draft versions of maps, which are examined by local officials before being made official, a process that can take months. Earlier this year, new maps became effective in Suffolk and Bristol counties - meaning anyone living there who now needs to buy flood insurance no longer qualifies for a reduced rate.

Boston city officials hope they acted in time to help homeowners in Dorchester’s Savin Hill neighborhood. The city notified about 80 of them that their homes are now in a flood plain - just before the new FEMA maps in Suffolk County became official.

Chris Busch, executive secretary of the Boston Conservation Commission, said officials took it upon themselves to send letters to homeowners and schedule a meeting with them after realizing FEMA was not doing so.

“We did our best to try to outreach,’’ Busch said. “Some of the smaller towns didn’t have the resources.’’

Mendelsohn said FEMA has been working to publicize the new maps, but that local municipalities are responsible for notifying property owners.

“We have been beating the bushes in terms of community meetings and talking to cities and towns in every county,’’ Mendelsohn said.

Counties, communities, and individuals can appeal the new flood risk designations if they can provide scientific and technical data that the maps are incorrect. Property owners also may request an official letter from FEMA if they believe a lender erroneously is requiring them to buy flood insurance.

It’s unclear how much a change in zoning could affect a property’s value. Easton appraiser Shaun Fitzgerald said being in a flood plain, along with the added insurance costs, will be likely to devalue a home. Buyers must factor in the price of insurance when they consider a new home, he said, since it is often built into monthly payments.

In Cambridge, officials held community meetings and sent letters and fliers to Alewife property owners to inform them of their homes’ inclusion in the flood zone. Residents were advised to contact their insurance companies or to appeal the designation before the maps become effective there next June.

Woodbury, the storm water coordinator, said she has seen water surge from Alewife Brook, across Alewife Brook Parkway, and into the nearby neighborhood.

Phoebe Bernard, who has lived near Alewife Brook for 12 years, said she was not aware of the change until informed of it by the Globe.

Bernard said she received fliers, but did not read them. Her house has never flooded, she said, but several neighbors’ basements have filled with water after storms.

“The last thing I need is to have my monthly expenses increase,’’ said Bernard, 39, who is unemployed.

But she said she understands the reasoning behind improved mapping. “They set up flood zones for people’s own protection,’’ she said.

Jenifer McKim can be reached at jmckim@globe.com.