UBC Undergraduate Research

Forest Disturbance Impact on Flow Patterns and Anion Exports by Streamwater for a BC Coastal Douglas-fir Headwater Catchment. Zhou, Jack

Abstract

The effect of disturbances in a forest, including logging and road construction, alters many hydrological processes in a forested watershed, changing overall hydrologic flowpaths and nutrient cycling. Changes in hydrologic pathways and anion export within a forested watershed near Campbell River, British Columbia were studied, with streamwater samples collected since 2007 and analysed via ion chromatography. Using segmented regression analysis (SRA), this study examines the concentration-discharge relationship between stream nutrient export and streamflow at the base of the catchment over a 4-year period that includes road construction and a harvest event that took place in early 2011. Observations include much greater discharge post-disturbance, previous patterns in chloride (Cl-) and sulphate (SO42-) could not be discerned after disturbance, and nitrate (NO3-) export were influenced by fertilization prior to disturbance but showed extremely low concentrations in the short period after logging. Changes in climate and precipitation patterns could explain several of the findings, while the short study period led to many uncertainties and difficulties in interpreting long-term trends and effects. The analyses conducted in this study, examining the anion flux in the stream water as compared to discharge, is a means of understanding the post-disturbance hydrology, assessing and corresponding changes in water quality.

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Attribution-NonCommercial-NoDerivatives 4.0 International