Beaver Dams in Madison and Oneida Counties, New York State, 1994-2022

This point dataset comprises georeferenced (NAD 1983 Zone 18N) digital markers of beaver dam locations in the Counties of Madison and Oneida in New York State in the years 1994, 2003, 2013, and 2022, as determined manually and retroactively through observation of true-color (rgb) composite aerial imagery from those years. The New York State Orthoimagery Database supplied the relevant imagery, and the years were chosen according to the availability of imagery for both counties at the time of data collection. The approximately 40-inch resolution photographs from 1994 were taken as part of the United States Geological Survey’s National Aerial Photography Program, whereas the 6- to 12-inch resolution images from the subsequent years were taken as part of New York’s GIS Coordinate Program. Each point represents a unique beaver dam determined to be present in one or more of the aforementioned years from such land feature characteristics as curvilinearity, perpendicular orientation to streams, proximity to apparent beaver lodges, and other distinguishing contextual clues. The attribute fields to the point data include the smallest unit of watershed in which the dam in question lies or once lay, the approximate location of the dam in terms of a named geographic feature, and one field for each year with a code indicating whether the dam was found to be present that year (1-yes, 0-no). This inventory has been used thus far in an investigation of the changes in dam abundance and distribution over the past three decades.