Stronger, more frequent storms could prompt flood plain changes

July 17--WILKES-BARRE -- Mother Nature's storms are striking harder and more often, prompting the federal government to increase its projection of the 100-year storm -- and potentially create zones in three Luzerne County communities with mandatory flood insurance requirements.

Authorities converged at the Emergency Management Agency building Wednesday afternoon to brief local government officials about plans to remap the flood plain around the Wyoming Valley Levee System, a four-year endeavor that could particularly affect residents of Wilkes-Barre, Hanover Township and Plymouth.

The levee, which has protected the Wyoming Valley from some $7.6 billion in damage and emergency response costs since 1968, is well-maintained and performing as expected, officials reported, but changes including storm severity, sedimentation on the river bed and structure placement have prompted the U.S. Corps of Army Engineers to increase its projection.

In 1990, the corps estimated the 100-year storm -- a high-magnitude event with about a 1 percent chance of occurring every year -- as moving 254,000 cubic feet of water per second down the Susquehanna River, said Harvey Johnson, chief of the corps' civil works branch in Baltimore. With four of the eight biggest storms on record occurring in the past 20 years, the corps bumped the estimate by 13 percent last year to 293,000 cubic feet based on an analysis that looked at storm data as well as geographic changes such as land use, he said.

"What used to be a 100-year event back when the project was originally designed, it's a much larger event now," Johnson said. "Upstream portions of the project were fine, but unfortunately when you go to the tail end of the Wilkes-Barre, Hanover Township, Plymouth Township, they were not overtopped by that event, but unfortunately they did not have the factor of safety we needed."

As a result, the corps recommended the Federal Emergency Management Agency accredit the levee at Kingston and Exeter, but not at Wilkes-Barre, Hanover Township or Plymouth, he said.

The "factor of safety" is measured in terms of freeboard -- the distance between the projected high-water mark and the top of the levee. The required amount of freeboard varies -- typically it is between two and three feet, Johnson said. The exact extent of the deficiency along the affected levee sections was not available Wednesday.

The lack of accreditation will not affect the current flood maps, but it will impact the next maps, which will begin next year with a process called the Levee Analysis and Mapping Procedure, said Eugene K. Gruber, mitigation division director for FEMA. New maps are expected to become effective in 2018, he said.

"That's when there may be an impact on flood insurance," Gruber said, adding that in some locations, residents could face a mandatory requirement to buy flood insurance. "That is not determined at this point -- what the impacts will be for the system as a whole, and especially for individual property owners."

Residents and local officials will have the opportunity to comment on preliminary maps before they take effect, he said. Communities will need to provide technical data to have an impact on the maps, and FEMA plans to work closely with local leaders during the process, Gruber said.

Luzerne County Flood Protection Authority Executive Director Chris Belleman said the issue is simply the passage of time since the levee-raising project.

"A lot's changed in 30 years," Belleman said. "The frequency and intensity of storms has increased, we've got increased land development in the watershed, the science has improved, the technology has improved to do this type of modeling. These have all coalesced together to come up with the results that we're seeing today, 30 years after the fact."

During the presentation for local officials, Gruber talked about several programs that could help communities lower flood insurance costs for residents.

West Pittston Mayor Tony Denisco questioned the possibility of expanding the levee system to protect his community, which is unprotected and saw 859 homes and businesses underwater in 2011, as well as others in the area such as Pittston, Duryea and Harding.

He also asked about whether there are plans to increase the height of the levee downstream, which he said would result in more flooding in his area.

"If it is, I might as well put the sign of the cross on my town, because I'm done," Denisco said. "I don't know where to turn."

Col. Trey Jordan, Baltimore district commander of the U.S. Army Corps of Engineers, replied that raising or expanding the levee is highly unlikely because of the huge expense.

"My gut is telling me that although those 850 homes are very, very important, the benefit won't be worth the amount of federal dollars," Jordan said.

Officials are holding public meetings on the subject next week. A meeting in Wilkes-Barre will take place from 6:30 to 8:30 p.m. Monday at Wilkes University's second floor ballroom at 84 W. South St. A meeting for Plymouth residents will take place from 6:30-8:30 p.m. Tuesday at Luzerne County Community College'sEducational Conference Center at 1333 S. Prospect St., Nanticoke.

570-821-2058, @cvjimhalpin

The Luzerne County Flood Protection Authority, Federal Emergency Management Agency and the U.S. Army Corps of Engineers will hold two meetings to unveil changes to the Wyoming Valley Levee System and the Luzerne County Flood Insurance Rate Map.

The meetings, which will be held from 6:30 to 8:30 p.m., will be held:

n Monday, July 21 in Wilkes University's second floor ballroom, 84 W. South St., Wilkes-Barre.

n Tuesday, July 22 in the Luzerne County Community College Educational Conference Center, 1333 S. Prospect St., Nanticoke.

For information or to arrange for disability accommodations, contact Flood Authority Executive Director Chris Belleman, 570-825-1601 or [email protected].

___

(c)2014 The Citizens' Voice (Wilkes-Barre, Pa.)

Visit The Citizens' Voice (Wilkes-Barre, Pa.) at citizensvoice.com

Distributed by MCT Information Services