Flood risk mapping in canada: 1. uncertainty considerations

Abstract

The uncertainty in specifying a flood risk area can be described as the vector sum of the uncertainties in water surface (flood) elevation and ground surface elevation. Each of these uncertainties is evaluated In terms of a standard error of estimate. For flood damage reduction program projects, the variation in uncertainty of ground elevation is small; the standard error is typically 0.3 metres. However, the variation in uncertainty in water elevation is much larger. The standard error ranges from slightly less than 0.3 metres to greater than 1 metre. Evaluating and reporting these two uncertainties and their vector sum is suggested as a means of enhancing the effectiveness of flood risk maps. © 1992 Taylor & Francis Group, LLC.