Steep channel freezeup processes: understanding complexity with statistical and physical models

Abstract

The development of ice dams in steep channels dictates water level variations and influences flow rates and habitat conditions. Despite the dominance of ice dam development in cold region gravel bed channels, practicing engineers and scientists have access to very little quantitative information describing this complex freezeup process. This paper aims to fill this gap by presenting a large data set on the process. The substantial variations observed in formation and melting rates from one site to the next and from one year to the next at the same site are explained with a physically-based numerical model that includes a complete heat budget applied to single step-pool sequence. The model successfully simulates the entire development of an ice dam and shows that the process depends on multiple parameters, or degrees of freedom. It also reveals that morphological characteristics greatly influence ice dam dynamics.