Indentifying Erosion Hazard to Municipal Infrastructure: Preparing for Extreme Events

The Town of Berne, in the Helderbergs of Albany County, NY, experienced severe damage as a result of Tropical Storm Irene on August 28, 2011. While flooding during the storm was a significant problem all along the Fox Creek, there was also extensive damage to municipal infrastructure resulting from erosion along roadsides, bridge approaches and small stream crossings. In the summer of 2013 the Town's Conservation Board hired a student intern to begin the process of assessing and mapping erosion hazard in the Town, as part of the effort to adapt to the expected increased frequency of intense rainfall events. Erosion hazard sites identified as resulting from Irene, and from other events, were surveyed and mapped (Figure 1); nearly 80 locations were documented. A conceptual model incorporating several factors--slope, drainage and substrate patterns, stream channel design and roadside ditch management--has been built which is based on observations of each site; the factors are being integrated as layers in a GIS model. The spatial distribution of event-specific rainfall relative to the watersheds in the northern Catskill Mountains, based on the NEXRAD station (KENX) located in the Town of Berne, is being integrated with the observed erosion site distribution to assist in evaluating a conceptual model of erosion hazard. Recommendations for mitigation and prevention of erosion damage to municipal infrastructure have been tailored to the observed type and distribution of erosion hazard in the Town. An overall goal is to create a basic format for assessing the potential for future erosion hazard.