DRY BROOK SUB-BASIN
The Dry Brook watershed is located within three different townships: the Town of Middletown in Delaware County, and the Towns of Shandaken and Hardenburgh in Ulster County. Arkville is the only population center in this sub-basin.
Dry Brook is a fifth order stream withthree major tributaries that enter the mainstem: Bush Kill, Rider Hollow,and Haynes Hollow. Numerous unnamed tributaries that have a small drainage area also contribute to themainstem. Bush Kill and Dry Brook merge together approximately 1 mile upstream of where Dry Brook enters the East Branch mainstem. The drainage area of Dry Brook is approximately 82.3 square miles and the mainstem is 12.5 stream miles in length from the headwaters to the confluence with the East Branch Delaware River mainstem.
The valley is generally broad to very broad and the valley side slopes are very steep with high run-off potential soils, making this watershed prone to flash flooding. The land use is predominately forested, with some agricultural fields interspersed. The average annual rainfall in the watershed can range from 37-39 inches/year at the lower portion to 55-57 inches/year in the headwaters.