John Trainor, USGS. Public domain

Mid-Atlantic - USGS Crews Work Fast to Capture Critical Flooding Measurements in the Mid-Atlantic

USGS Crews Work Fast to Capture Ida Critical Flooding Measurements

To learn more about USGS’s role providing science to decision makers before, during and after Ida, visit https://www.usgs.gov/Ida

Five days after Hurricane Ida made landfall, leaving behind catastrophic flooding and significant damage in its path, U.S. Geological Survey scientists started quickly working a multi-week effort to capture high-water mark elevations in some of the most impacted areas. Teams from USGS water science centers in New York, New Jersey, Pennsylvania, and Maryland are working together to preserve, document, and survey elevations of more than 200 combined high-water marks left from flooding caused by Ida’s heavy rains.  

“We are working with federal and state partners, along with the New York City mayor's office to coordinate our high-water mark collection effort in the hardest-hit communities of New York City,” said Ronald Busciolano, a supervisory hydrologist at the USGS New York Water Science Center.  “Our marks will provide ground-truth to other ongoing mapping efforts and be used by emergency managers to define the extent and depth of flooding in impacted areas, which decision-makers can use as they work to protect their communities from future flooding."

The locations were assigned to the USGS with guidance from the Federal Emergency Management Agency, National Weather Service, U.S. Army Corps of Engineers, river basin commissions, and emergency management officials. One hundred marks will be recorded in New York and 50 in New Jersey. The Pennsylvania and Maryland crews will record 75 and 33 locations respectively in southeastern and central Pennsylvania and northern Maryland.

The USGS experts are looking for telltale lines of seeds, leaves, grass blades and other debris left behind on buildings, bridges, other structures, and even tree trunks as floodwaters recede. Once they find these high-water marks, they label them, photograph them, survey them, and record crucial details about them. The physical signs of flooding provide valuable information that can confirm or correct other lines of evidence.

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