Effects of recreational flow releases on natural resources of the Indian and Hudson Rivers

Base flow in the Indian River downstream of Lake Abanakee, July 29, 2004

Recreational release flow in the Indian River downstream of lake Abanakee, July 29, 2004

Rainbow trout

Brown trout

The New York State Department of Environmental Conservation (NYSDEC) is developing a unit management plan/environmental impact statement (UMP/EIS) for the Hudson Gorge Primitive Area, an area of Forest Preserve land encompassing a scenic stretch of the Hudson River in the Adirondack Park. Two goals of the UMP/EIS are to inventory natural resources and ecosystems and take actions to protect those resources while providing for appropriate types and levels of public recreational use. Because of the river's extensive whitewater reaches, it is the setting for a commercial rafting industry that operates during spring, summer, and fall. To increase flows in the Indian and Hudson Rivers, the Town of Indian Lake conducts regular recreational releases from Lake Abanakee which is located on the Indian River about two miles above its confluence with the Hudson. The stretch of the Indian and Hudson Rivers traversed by rafters is also important to anglers who seek brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss). The anglers are concerned that the recreational flow releases negatively affect trout survival and abundance through habitat loss, hydrologic disturbance, and (or) reductions in availability of suitable prey organisms (minnows and macroinvertebrates). The effects of these releases on the overall ecosystem (including all local fish species, the macroinvertebrate community, and riparian wetlands) of the two rivers and Lake Abanakee are also of interest. Basic hydrology, geomorphology, habitat, and biology data for the Indian and Hudson Rivers, and for Lake Abanakee, are essential for evaluating impacts of the releases and developing appropriate management strategies, but these data do not currently exist.

A cooperative study by the NYSDEC and the U.S. Geological Survey (USGS) is planned to provide information that support goals of the UMP/EIS. Primary objectives of this multidisciplinary effort are to evaluate the effects that recreational flow releases from Lake Abanakee have on (1) hydrology, temperature, wetlands, resident fish and invertebrate communities in the Lower Indian River and the gorge region of the Hudson River, (2) behavior of stocked trout (brown or rainbow) in affected reaches in the two rivers, and (3) lake elevation (stage), wetland area and fish communities in Lake Abanakee. The project is scheduled to start in the fall 2004 and sampling efforts will continue for three-to-four years.

Results from the study are being summarized in several reports and refereed journal articles and will be available in the links below and on the USGS web page http://ny.usgs.gov.