Since 1995, IRIS has been working with the Hudson River National Estuarine Research Reserve and the Hudson River Estuary Program, to inventory and map submerged aquatic vegetation (SAV) as part of a continuing effort to monitor SAV in the Hudson River. Three comprehensive river-wide inventories have been completed. In 1995, the first inventory of SAV and Trapa natans was conducted on what is now referred to as the "main stem" of the river. In 2002 and 2007, two more SAV inventories were undertaken with an expanded area of study which included coves and major tributaries. Nine major tributaries were identified as part of the SAV mapping area: Rondout Creek, Catskill Creek, Esopus Creek, Annsville Creek, Croton River, Stockport Creek, Moodna Creek, Fishkill Creek, and Wappinger Creek. An inventory for 2014 is currently underway.
Each inventory maps SAV and Trapa natans (water chestnut) from Troy to Hastings-on-Hudson. Past reports and associated documents have referred to SAV and Vallisneria americana interchangeably. This usage is based on fact that Vallisneria americana (water celery) is the dominate species (90%) of the SAV community.
The objectives in performing the current 2014 mapping are: 1) Document existing SAV and Trapa natans plant presence and extent using digital aerial imagery; 2) Identify areas of change between the 2007 and 2014 mapping; and 3) Conduct a river-wide accuracy assessment of the 2014 mapping effort. Monitoring has demonstrated that SAV beds may disappear and return, probably in response to a variety of factors. Documented SAV Habitat merits stringent protection by managers and regulators.
Data and documentation may be obtained from the New York State Clearinghouse.