Harold Walker is director and professor of civil engineering at Stony Brook University. Prior to coming to Stony Brook, Dr. Walker was a professor in the Department of Civil, Environmental, and Geodetic Engineering at The Ohio State University. Dr. Walker also served as the director of the Ohio Water Resources Center, the federally authorized and state-designated water resources research institute for the state of Ohio. Dr. Walker served on the board of directors of the National Institutes for Water Resources as well as on the board of directors for the Water Management Association of Ohio. Dr. Walker is a registered professional engineer in the state of Ohio. He has a BS in environmental engineering from Cal Poly San Luis Obispo and MS and PhD degrees in civil and environmental engineering from the University of California, Irvine. Dr. Walker’s research focuses on understanding surface chemical processes in natural and engineered systems, with an emphasis on clean water. Current areas of research include predicting the fate and transport of manufactured nanomaterials, cyanotoxins, and other "emerging" contaminants in groundwater, lakes, oceans, and water treatment plants; developing novel membrane treatment systems and membrane cleaning approaches; and determining the vulnerability of the public to cyanotoxins in finished drinking water. Dr. Walker has secured external funds to support his research from a number of sources, such as the National Science Foundation (NSF), US Environmental Protection Agency (USEPA), United States Geological Survey (USGS), Department of Energy (DOE), National Oceanic and Atmospheric Administration (through Sea Grant), and a variety of state agencies, industries, and other sources.