Author(s): Benoit Turcotte; Francois Rainville
Linked Author(s):
Keywords: River Ice; Environmental Aspects Related to Icy Waters
Abstract: The quantity of water flowing in streams and rivers represents the most important hydrological parameter to several water data users. Critical societal activities depend on the availability of accurate discharge estimations. A significant constraint to cold regions hydrometry, the science of monitoring water, is the absence of simple tools to convert water level (or stage) measurements into accurate discharge (flow) estimates when different types of stationary ice are present in the channel. Beyond the complex departure of the actual discharge from the open water rating curve, upstream river ice processes can also generate significant discharge fluctuations, especially when ice conditions are rapidly changing. The overlapping effect of local and upstream (watershed scale) ice processes on stage means that producing continuous winter discharge estimates involves uncertainties that some users may find unacceptable. A solution to this complexity would be to seek alternative monitoring technologies and data processing models. However, our understanding of the impacts of ice processes on stage and discharge is still rudimentary and most proposed winter discharge estimation techniques to date have shown limitations that prevent their application to a broad range of hydrological contexts. This paper proposes and tests a new procedure to support the production of winter discharge estimates from three complementary angles (improved understanding, adapted tools, and targeted technology). The research presented emphasizes the development of hydrological station-specific knowledge that applies to a broad range of winter scenarios as well as analytical tools that use readily available information in order to guide the judgment of hydrometry technologists and their supervisors. Results, presented for Yukon stations, reveal that discharge estimation errors in the order of 100% are probably common, especially during freeze-up. Significant improvements to winter discharge estimates, in terms of reproducibility and accuracy, can unquestionably be obtained, even using parameters that are currently monitored. Main research outcomes are listed, and future research steps are proposed.
Year: 2022