Flood of October 31 to November 3, 2019, East Canada Creek, West Canada Creek, and Sacandaga River Basins

Between October 31 and November 3, 2019, historic flooding in parts of the Mohawk Valley and southern Adirondack region resulted in one fatality, an estimated $33 million in damages, and the declaration of a state of emergency for 13 New York counties. Flooding resulted from high-intensity rainfall within a 24-hour period between October 31 and November 1, 2019, at the end of an October that had much higher rainfall than normal. In that 24-hour period, rainfall amounts in the most heavily affected parts of the region largely ranged from about 2 to 5 inches, but a maximum rainfall amount of 7.00 inches was recorded in Speculator, NY in Hamilton County. In this location, a rainfall of 7.00 inches in a 24-hour period is estimated to have between a 200- and 500-year recurrence interval or between a 0.5- and 0.2-percent chance of happening or being exceeded in any given year.

The most severe flooding from October 31 to November 3, 2019, was mainly in the East and West Canada Creek basins, which are within the Mohawk River basin, and the Sacandaga River basin, which is within the upper Hudson River basin. Flooding resulted in new peak streamflow records at eight of nine selected U.S. Geological Survey streamgages from the region, including at three streamgages that have been in operation for about 100 years. At East Canada Creek at East Creek, NY (01348000), flooding resulted in the second highest peak streamflow in its 71-year period of record. National Weather Service major flood stages were exceeded at the three streamgages in the region where National Weather Service flood stages have been established and were exceeded at Hinckley Reservoir at Hinckley, NY (01343600). Hinckley Reservoir has a drainage area of 372 square miles and regulates West Canada Creek streamflow about 31 miles upstream of West Canada Creek at Kast Bridge (01346000) and 3 miles downstream of West Canada Creek near Wilmurt, NY (01343060).

In West Canada Creek, downstream of Hinckley Reservoir, a distinct double peak of streamflow happened during the 2019 flood and was recorded at West Canada Creek at Kast Bridge, NY (01346000). A similar, but less distinct, double peak was recorded at Mohawk River near Little Falls, NY (01347000), which is located 14.8 miles downstream of West Canada Creek at Kast Bridge, NY (01346000). The first peak of the double peak was likely caused by inflows to West Canada Creek from unregulated tributaries downstream of Hinckley Reservoir, such as Cincinnati Creek, which drains a relatively large area of 48.5 square miles in the northwest corner of the West Canada Creek watershed. Cincinnati Creek was ungaged at the time, but in response to the flood, the U.S. Geological Survey, in cooperation with the New York State Canal Corporation, installed a gage at Cincinnati Creek at Barneveld, NY (01344795) that has been in operation since November 2022. The second peak of the double peak, which happened about a day after the first peak, likely resulted from regulated streamflow that passed through Hinckley Reservoir. At the other streamgages upstream of Hinckley Reservoir, single peak streamflows were recorded during the flood. More details on the nature of the flood of October 31 to November 3, 2019, including the historic context of the flood, and the results from flood-frequency analysis of six selected streamgages in the Mohawk Valley and southern Adirondack region, are discussed in Graziano and others (2024).