The seasonal and inter-annual variation in water export from a boreal forest headwater stream

• Main Author: Athukorala, Dilanka Niroshan
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 2020
• Subjects: Newfoundland; Canada; Ferguson
• Online Access: https://research.library.mun.ca/14531/; https://research.library.mun.ca/14531/1/thesis.pdf

Headwater streams are important locations representing access points to assess aquatic to terrestrial fluxes and source areas that control the water and solute fluxes to downstream aquatic environments. Boreal headwater streams are in post-glacial high latitude landscapes which show a wide range of topographical heterogeneity in landscapes containing high stores of organic matter highly susceptible to climate change. Boreal streams represent important sentinels for landscape changes relevant to global climate feedbacks. Catchment hydrology of boreal streams is controlled by the precipitation regime, particularly snow dynamics and the connection between the landscape elements and hydrology. Snowfall and snowpack dynamics are important features impacted by recent climate change over the last recent decades with potential to significantly impact catchment hydrology of boreal streams and thereby terrestrial to aquatic transport of water, solute, and nutrients in these high latitude landscapes. In this study, I investigated two key boreal headwater components (low gradient wetland and pond and upland forest regions) making up one third order stream watershed situated in western Newfoundland and Labrador in Canada. The second chapter describes a series of approaches evaluated for extending the rating curves required to obtain discharge estimates from continuously monitoring water level in remote, rocky small boreal streams beyond field measurement limited by access during key high flow periods. Results of this study suggest that the use of Ferguson flow resistant equations, which help to better inform the discharge-gauge height relationship through incorporation of stream geometry including stream cross-section, stream gradient, and stream bed grain size data, significantly improves discharge estimates. The third chapter focuses on the study of water flux dynamics of a third order stream in three years contrasting in winter and snowmelt dynamics. The goal of this work was to assess how annual and seasonal discharge ...