Genesee River

About

Genesee River, New York — 381 Million Year Old Gorge, Letchworth. The Genesee began carving its course through bedrock laid down deep in geologic time, and the proof endures in the Mount Morris dam shales, dated at 381.1 ± 1.3 million years ago. Draining 2,468 square miles, the river runs north through a string of communities from its Pennsylvania headwaters to its confluence with Lake Ontario at Rochester. Long before mills and dams, the Genesee Valley was the heartland of the Seneca Nation — the westernmost of the Haudenosaunee Confederacy and known as the 'Keepers of the Western Door.' The fertile bottomlands supported large Seneca agricultural villages until the 1779 Sullivan Expedition destroyed dozens of them along the river, ending Haudenosaunee dominance of central New York.

Settlement followed. The Holland Land Company purchased the river's watershed between 1797 and 1826, and the 1837 founding of Rochester turned the river's descent into industrial power. The 1842 Genesee aqueduct — the only bridge to cross the river at Rochester for 60 years — helped make the city the 'Flour City' of the 19th century. Upstream, the river's watershed was logged from the 1830s through the 1920s, feeding local sawmills, logging drives, and downstream lumber operations, and supporting both the regional timber industry and railroad expansion. The exhaustion of the old-growth stands by 1910, the start of state forestry conservation in 1915, and the establishment of state forests in the 1930s ended large-scale logging.

The river's most spectacular stretch is its gorge. In 1907, William Pryor Letchworth donated 1,000 acres along the Genesee Gorge to New York State, creating the nucleus of Letchworth State Park. The park now protects 14,400 acres along 17 miles of gorge known as the 'Grand Canyon of the East' — 600 feet deep, exposing the 381-million-year-old shale and sandstone that records the river's age. It stands as one of the most spectacular protected landscapes in the eastern United States and carries a New York State Scenic River designation.

That same descent made the valley prone to flooding, and after a 1942 flood, engineers completed the Mount Morris Dam in 1952 to shield Rochester and the river's floodplain. It remains the largest flood-control dam east of the Mississippi. The dam also divides the river for paddlers: the Letchworth Gorge above it is closed to paddling and viewable only. Study of the river ran alongside its taming — from the 1870s–1890s USGS surveys and 1880s–1910s gauging stations to the 1950s–1970s state water pollution control studies and the 1972–2000 Clean Water Act assessments that addressed a century of logging, agricultural, and industrial impacts.

Today the Genesee carries a mix of water. The USGS gauge 04231600 records an average of about 1,300 CFS, with an optimal paddling window of roughly 400–2,500. The Upper Genesee runs 50 miles of Class I from Wellsville to Letchworth through a rural valley. Below Mount Morris Dam, the Lower Genesee runs 60 miles of Class I–III from Mount Morris to Rochester, shifting from suburban to urban, with commercial whitewater rafting available below Letchworth. The 2018 Genesee River Basin Action Agenda from NYS DEC continues the long arc of study, restoration, and TMDL work on a river that has been both an ancient geologic record and a working waterway for as long as anyone can measure.