Levee Operation & Maintenance: Risk Reduction at a Dynamic Site 1959 to Today

ABSTRACT ONLY - What should one do when conditions around a federally-constructed levee and channel project change? New York State Department of Environmental Conservation (NYSDEC) has adapted operation and maintenance practices over the past six decades to keep pace with changes in the 27 acres former air force plant site in Johnson City, NY. The site is part of the Johnson City / Westover flood risk management project built by the United States Army Corps of Engineers (USACE) in 1959. To minimize risk to the leveed area, railroad closure structures were permanently installed due to lack of traffic circa 1989, saving approximately 56 person-hours during flood events for avoided installation and removal. A highway on-ramp was built over the levee with placement of stone armor due to shaded area and loss of sod cover in 1969. The upstream railroad trestle bridge was removed circa 1970s, and the second railroad bridge was removed in 2017 by NYSDEC, with option for future replacement for landowner site development, with an estimated $6,000 annual savings due to fewer removals needed for debris jams. Overtopping during 2006 and 2011 floods from both Little Choconut Creek and the Susquehanna River caused the air force plant to relocate. Storm sewer collection systems were removed, but four storm drain conduits, two local pump station discharge pipes, and a sanitary trunk line remain penetrating the levee/floodwall. The adjacent stoplog closure over five lane state highway takes approximately 26 person-hours to install. Design plans are pending for a slide gate closure to greatly reduce installation time, and initial assessments have been completed for floodwall rehabilitation. Modern operations include a flood patrol manual in pdf, google earth GIS layer, and laminated paper copies of maps and narrative patrol routes, which allows patroller staff from non-flood protection programs to quickly become familiar with project location and features, provides consistent geographic referencing, and avoids confusion during flood response. Patroller trainings are held periodically and closure drills annually. Routinely used maintenance equipment includes tractor mowers, boom mower, excavator, and skid steer. Aside from the recently vacant lot becoming a breeding ground for woodchucks, floodplain restoration of 14 acres was proposed in the USACE 2020 Upper Susquehanna River Basin Study by realigning the levee. Other concepts for site redevelopment include athletic fields with stormwater ponds. In summary, local levee sponsorship is an ongoing effort that requires adaptability and substantial staffing, equipment, and financial resources to manage flood risk.