SPATIAL DISTRIBUTION OF BASEFLOW DISCHARGE IN THE LITTLE CHAZY RIVER WATERSHED, CHAMPLAIN LOWLAND, NEW YORK

This study examines baseflow generation in the Little Chazy River watershed of northeastern New York using a nested network of 15 gauged subwatersheds. The Little Chazy River (basin area = 142 km²) flows eastward from the Adirondack foothills to its mouth at Lake Champlain. The uplands have moderate relief (~280m local relief), relatively thin soils (generally >3m) with extensive areas of exposed sandstone bedrock at Altona Flat Rock. The lowland region has low relief (<180m local relief) and deep (>3m) soils developed in glacial, lacustrine and marine deposits. Previous work found baseflow generation in the Little Chazy River to be spatially heterogeneous and seasonally variable. Two influent reaches were recognized along the mainstream, one on Altona Flat Rock at the site of a failed hydroelectric generating station and another in the lower reaches of the mainstream just above the village of Chazy. This study confirms baseflow relationships observed in the mainstream and extends the study into Tracy Brook (basin area = 25km²), one of two principal tributaries in the watershed, where similar conditions are found. At low baseflow discharge most streamflow in both the mainstream and Tracy Brook is generated where the streams descend along the western flank of the Champlain Lowland. The streams lose discharge as they traverse the Champlain Lowland in the vicinity of Chazy. At times of higher baseflow, a greater proportion of streamflow is generated in lowland subwatersheds.