Rapid Remote Assessment of Culvert Flooding Risk

Abstract

Failure of aging, undersized, and poorly maintained culverts is a problem throughout the United States. A lack of data on culvert location and condition complicates decision-making around their repair and replacement. This technical note presents an ArcGIS- and Python-based tool to support the collection of culvert data and estimation of flooding risk, and applies the tool to a case study of culverts within the Hudson River Estuary watershed of New York State. The tool follows two main steps: (1) estimate peak storm discharge for current and future precipitation conditions at each culvert location using the graphical peak discharge method, and (2) compare these values to a conservative estimate of culvert capacity, assuming a submerged inlet under inlet control. The case study demonstrates the ability of this tool to analyze more than 2,000 culverts using data obtained from an open database. The results from this tool can ultimately support municipal decision-making, as evinced by the use of the generated flood risk data in 12 municipal management plans underway within the Hudson River Estuary watershed.