Old Lyme - Old Saybrook Selectman William Peace saw the immediate utility in being able to visualize the best projections available on the effects of rising sea levels on his town, both for the present and for future decades.

"We're considering reconstructing our police station. I'd like to see the worst case scenario for 2050, when the bonds would be paid off," he said, addressing his request to Nathan Frohling, lower Connecticut River program director for the Nature Conservancy, and Ben Gilmer, conservation geographer for the conservancy's Global Marine Initiative, during a demonstration Wednesday of a new online tool to help towns prepare for climate change effects.

Stationed at a laptop computer connected to a large overhead screen, Gilmer selected maps and overlay information in the tool for the section of Main Street where the police station is located. A swath of blue then covered portions of the map to show where flooding would occur in various scenarios: sea-level rise estimates in the years 2020, 2050 and 2080 with and without hurricane conditions in various magnitudes.

To Peace's relief, the police station, while not spared from flooding due to record rainfalls a year ago, looked like it would be safe from the kind of flooding rising sea levels and storm surges could cause.

But for other parts of town where periodic flooding that is already a reality is likely to intensify, the tool points out the need for some tough decisions about long-term solutions.

"It seems to be a good tool," Peace said.

According to the conservancy, a free online tool can help town officials "analyze the ecological, social and economic impacts" of sea-level rise on their communities and will offer a menu of potential responses. Peace was among more than 50 officials at the workshop from towns along the Connecticut coast, from Fairfield County to New London County, who came to learn how to use the tool. Locally, Old Lyme, Groton, Waterford, Stonington, Salem and East Lyme were represented.

Old Saybrook, though, had a distinction among the communities represented: the conservancy has chosen Old Saybrook and Guilford to be pilot towns that will receive special instruction. Officials from the two towns will learn how to pair information from the tool with other town data, such as assessor's maps and property values, to understand what neighborhoods with high poverty levels or high percentages of elderly residents are particularly vulnerable to flooding.

Officials will also learn how to apply the data to plan for development, emergency management and land conservation.

A town could, for example, identify a neighborhood vulnerable to flooding next to a marsh and then focus conservation efforts on acquiring open land next to the marsh that could serve a dual purpose, said Adam Whelchel, director of conservation programs for the conservancy. The marsh habitat would be preserved because it could migrate to the open area inland, and the protected area would serve as a buffer for floodwaters approaching the neighborhood.

Peace said he attended a meeting the conservancy hosted a year ago when it began developing the tool and expressed interest. He noted that eight other Old Saybrook officials and members of town land-use boards attended the workshop.

"We had a great curiosity," he said. "Over the next 20 years, what can we expect?"

Frohling said conservancy staff will work directly with officials in the pilot towns on using the tool and developing an action plan. Outreach to specific neighborhoods is planned.

"We also want to work with communities affected, not just town officials, so they are as bought into this," he said. "This is a politically sensitive issue."

Sandy Prisloe, environmental planner for Old Saybrook, agreed that what the tool shows could be difficult for some residents.

"The tool can be very useful, but it raises as many questions as it answers," he said. "How do you deal with people in the affected areas?"

Officials from other towns said coastal communities need to work together to plan for rising seas so that one town's solution doesn't worsen flooding for its neighbor. Overall, workshop attendees agreed the tool provides a way to see and understand what climate change will mean on a local level.

Hearing that sea level is expected to rise a certain amount by 2020 or 2050 "is somewhat meaningless unless you can visualize it," said Bruce Hyde of CLEAR, the Center for Land Use Education and Research at the University of Connecticut.

j.benson@theday.com

MORE INFORMATION

For more information, visit

www.coastalresilience.org and click "Geographies," then "Long Island Sound"