“The wetland maps for Tompkins County date from the 1980s,” said Nick Hollingshead. Hollingshead was there to report on the Wetlands Mapping Project for the Cayuga Lake Watershed Network.
He first got started on the project by mapping wetlands in Dryden in 2014. While the old Fish and Wildlife Service maps were created from aerial photographs on film, new technology has made more accurate mapping possible. Hollingshead is using LiDar, a surveying technology (the term “lidar” was actually created as a portmanteau of light and radar) that measures distance by illuminating a target with a laser light and GIS. “For the most part, LiDar made this possible,” said Hollingshead. The imagery was collected in March, “when saturation of the ground is visible.”
Wetlands in New York State, to be protected under DEC law, must be larger than 12.4 acres, Hollingshead explained. However, significant wetlands exist that don’t meet that criteria. The wetlands mapping project’s ultimate goal is to provide accurate data to municipalities in order to support regulatory protection of local wetlands. The Water Resource Council has drafted a local wetlands law, but “better data would be helpful,” said Hollingshead. To this end, the Cayuga Lake Watershed Network and the county have hired Hollingshead to do the mapping project using LiDar.
Hollingshead said that the DEC counts 5,600 acres of wetlands “whereas my data is 15,000, which I believe is closer to the actuality.” The DEC mapped 81 wetlands larger than 12.4 acres; “I mapped 197,” said Hollingshead.
In order to test his accuracy, Hollingshead mapped known wetlands within Cornell’s purview, gaining a 97.5 percent accuracy score.
