LAFAYETTE — A new flood map for Lafayette Parish could be finalized by next year, the first update since 1996 for a document that affects insurance rates and the required elevation of new construction in flood zones.

The Federal Emergency Management Agency has delivered the revised flood map to city-parish officials, and a tentative timeline calls for the map to be officially adopted by June 2012, City-Parish Public Works engineer Mark Lavergne said Wednesday.

In established residential areas, there are no major changes, but some flood zones will shift — moving property out of a flood zone classification in some areas and into a flood zone classification in others, Lavergne said.

“It’s not a grand scale,” he said. “Minor changes.”

The biggest impact of the new flood map could be on future developments of some large tracts of vacant land that will be classified as floodways.

The floodway designation —generally reserved for areas along a waterway — is more restrictive than the more common flood zone designation and brings tough guidelines for new developments.

New floodways on the proposed map include large swaths of land along major drainage coulees in the Scott area and along sections of the Vermilion River in north Lafayette, including undeveloped portions of the Louisiana Avenue/Interstate 10 interchange.

FEMA first proposed the new flood map for the parish in 2007, but city-parish government had raised an extensive appeal that stretched for more than three years.

The proposed map that is now being reviewed emerged from that process, and most of the flood designations are in their final form and not subject to further appeal.

The exception is for property within the Anselm Coulee drainage basin and parts of the Isaac Verot Coulee drainage basin, an area in southern Lafayette Parish west of Broussard and Youngsville, Lavergne said.

He said the area was studied late in the process of developing the new map and is still subject to appeal.

City-parish government is hosting an open house from 2 p.m. to 8 p.m. on Thursday at the South Regional Library on Johnston Street for property owners in those areas to see how the proposed flood designations might affect them.

Representatives from FEMA and city-parish government will be on hand to answer questions, Lavergne said.

He said the open house is geared toward property owners in the Anselm Coulee and Isaac Verot Coulee areas, but anyone with questions about the proposed flood map may attend.

Any residents whose property will be in a new flood zone should consider purchasing flood insurance before the proposed flood map goes into effect, Lavergne said.

He said if the insurance is purchased before the new map is finalized, the property will be grandfathered in at the insurance rate for property not in a flood zone — with rates as little as $200 a year compared to more than $2,000 a year for flood insurance in a FEMA flood zone.

ON THE INTERNET:

To view the current and proposed flood maps, visit: http://www.lafayettela.gov/pzc/floodzonemap.asp