UNDERSTANDING SEDIMENT DYNAMICS IN THE BUFFALO RIVER: CONTRIBUTING TO THE RESTORATION OF A GREAT LAKES AREA OF CONCERN

The lower 9.2 km of the Buffalo River is designated by the International Joint Commission as an Area of Concern (AoC). This urbanized watershed has experienced over a century of industrial activities resulting in environmental impairments including degraded habitat, low oxygen levels, restrictions on consumption of fish, and contaminated river bottom sediments. Of particular concern in the Buffalo River is how best to address the bottom sediments that contain elevated levels of organic compounds and heavy metals. Classified as a federal navigation channel, the United States Army Corps of Engineers (USACE) periodically dredges parts of the river to maintain a depth of 6.7 m below mean lake level. Channel deepening by dredging has affected the natural flow and sedimentation processes. The river is influenced by a Lake Erie driven flow regime related to wind-generated seiches that elevate water at the eastern end of the lake. During low flow periods in the Buffalo River, lake waters enter resulting in flow reversals. Over the past 15 years, we have conducted Sediment Trend Analysis studies to determine sediment transport pathways and side-scan sonar surveys to map bedforms. Findings show a bidirectional flow regime that controls sedimentation with reverse flow in the river related to high amplitude seiches. To understand the magnitude and behavior of seiches within the river, horizontal and vertical Acoustic Doppler Current Profilers (ADCPs), temperature and meteorological stations have been deployed between the river mouth and upper end of the AoC. Findings show a river oscillation with a period of ~1.5 – 2 hours and flood events with velocities >230 cm/s. ADCP data show the influence of lake incursions for 4 – 5 km, reaching a stretch of the river where sedimentary furrows are present. To support and inform river restoration decision-making our understanding of river dynamics has been shared with the U.S. EPA’s Great Lakes National Program Office (GLNPO), New York State Department of Environmental Conservation (NYSDEC), and the Buffalo Niagara RIVERKEEPER® (BNR), a member of the Waterkeeper Alliance. A public-private partnership involving GLNPO, BNR, Honeywell, NYSDEC, and the USACE is addressing environmental problems affecting the Buffalo River and a large-scale sediment removal project currently is underway.