New London — The most detailed images ever created of the bottom of eastern Long Island Sound are being made as part of a multi-agency project scheduled to conclude later this month. 

The National Oceanic and Atmospheric Administration is leading the seafloor mapping project from its vessel Nancy Foster, which was docked at Fort Trumbull State Park Friday and open for media visits.

“We’re mapping the topography and habitats, much more detailed than we’ve ever done before,” said W. Russell Callender, assistant administrator for NOAA’s National Ocean Service, surrounded by computer screens of sonar images of the estuary bottom in one of the main mapping rooms aboard the ship.

The project in the eastern Sound, which follows completion of a similar project in the central Sound, began last year.

Maps are created using side-scan sonar technology that sends out 1,500 sound waves per second to determine the contours of the seafloor, Callender said.

The project, which will continue with mapping of the western Sound, is being funded with $1.38 million from a June 2004 settlement between the two states that share the Sound — Connecticut and New York — and the Long Island Power Authority, Northeast Utilities and the Cross Sound Cable Company over adverse impacts caused by an underwater utility cable.

Timothy Battista, chief scientist on the Nancy Foster, said the maps show “a very refined picture of the sea floor, all the nooks and crannies.”

They distinguish hard-bottom areas from oyster reefs, eelgrass beds from sandy-bottom areas, rocky terrain and shipwrecks, along with precise dimensions of the structures.

Partners in the project include the environmental protection agencies of Connecticut and New York, several academic institutions including the University of Connecticut, Connecticut and New York Sea Grant, and the Environmental Protection Agency.

After the data collected for the maps has been analyzed and checked, the maps will be publicly available.

Dennis Schain, spokesman for the Connecticut Department of Energy and Environmental Protection, said the maps will be valuable in developing the state’s first “Blue Plan,” which will help guide future uses of the Long Island Sound seafloor.

In addition, Callender said, the maps will be useful tools for agencies such as the EPA and the U.S. Army Corps of Engineers as they consider permit applications for projects in the Sound, as well as for academic scientists, fishermen and developers considering aquaculture operations and new energy projects.

“Without this kind of information, you’re challenged in making decisions about any kid of offshore infrastructure,” Battista added.

Will Sautter, marine GIS analyst on the Nancy Foster, said the maps created of the eastern Sound thus far have revealed numerous changes in the contours of certain areas since they were last mapped with less precise equipment about a dozen years ago.

The changes are evidence of the effects of Superstorm Sandy and other major storms on the estuary, he said.

“The bottom is pretty dynamic,” Callender said.

j.benson@theday.com

Twitter: @BensonJudy