ADIRONDACK RIVER DISCHARGE TRENDS OVER THE PAST ONE HUNDRED YEARS

Discharge volumes for 17 rivers draining the Adirondack Mountains were analyzed as a group project by our Spring 2006 hydrology class. Fourteen of the seventeen rivers showed trends indicating small to moderate overall increases in annual discharge over the period of record keeping (generally 80-100 years), the remaining rivers (n=3) had constant discharge over time. When analyzed for mean monthly discharge variations over time, nearly all of the rivers showed increases in flow during the months of August (n=14), September (n=14), October (n=15), November (n=15), and December (n=16). While nearly half of the rivers showed overall decreases in flow during the spring during March (n=9), April (n=8), May (n=11), and June (n=8). These trends in the data appear to suggest: 1) the annual average stream discharge volume has increased throughout the region over the last one hundred years; 2) increases in stream flow are most pronounced in late summer though early winter; 3) despite a strong increase in annual discharge volumes, net decreases in stream flow occur monthly in some rivers; and 4) these decreases occur primarily in the spring months. In terms of regional climatic change, the data appears to suggest the last one hundred years have been a period of increased precipitation and runoff over most of the Adirondacks, during which fall discharge has increased and spring discharge has decreased throughout most of the region. The data utilized in this project is freely available on-line from the United State Geological Survey and is ideal for educational activities.