Homogeneous region delineation based on annual flood generation mechanisms

Abstract

Flood distributions can have unimodal or multimodal densities due to different flood generation mechanisms such as snowmelt and rainfall in the annual flood series. When applying nonparametric frequency analysis to annual flood data from the province of New Brunswick in Canada, unimodal, bimodal and heavy-tailed distribution shapes were found. By grouping basins with similarly-shaped densities on a geographical basis, homogeneous regions were delineated. Regional equations derived for a homogeneous region gave lower integral square errors than those of province-wide equations.     

CRUSTAL MOVEMENT OF THE GREAT LAKES—TIME SERIES ANALYSIS

ABSTRACT

Time series techniques were employed to determine rates of vertical crustal movement within the Great Lakes region of North America. Observations of water level elevations as recorded at gauges around the lakes, and differences in elevations between pairs of gauges were analysed for linear trends, periodicities and stochastic components. It was found that the variance of time series of elevations consisted mainly of first-order linear trends and small periodic components. Relative rates of crustal movement were computed from a linear trends analysis of elevation differences. These rates were converted to absolute rates of movement using the Nipissing zero isobase as a datum.

This study shows that, in general, the northeastern area of the Great Lakes region is rising at a rate of about 1·00 ft per 100 years relative to the southwest of the region.