Process-based modelling of stream temperature dynamics in a glacially fed river system
department or school: Arts, Faculty of
department or school: Geography, Department of
data provider: DSpace
degree campus: UBCV
creator: Browning, Billy
issued: 2023-08-29T22:15:02Z
issued: 2023
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: Glacially fed streams face increasing threats due to changes in stream temperature and flow from continued glacier recession and climate change. These systems support unique ecological communities, often highly sensitive to thermal changes. However, understanding the governing processes of stream temperature in large glacially fed stream reaches remains limited, with a lack of literature focused on larger rivers with tributaries. The objective of this study was to quantify the drivers of stream temperature dynamics in a 24 km long reach of the glacially fed Lillooet River in the southern Coast Mountains, BC. To support the application of HydroCouple, a reach-scale process-based stream temperature model, a new stream shading model was developed that used a LiDAR digital surface model to simulate shade from riparian vegetation and a conventional DEM to simulate topographic shade. Based on a comparison with shade interpreted from high-resolution PlanetScope imagery, the model simulated shade accurately both at individual points and for reach-scale averages. The model was used to simulate incident shortwave and longwave radiation at the stream surface. Air temperature, vapour pressure and wind speed were monitored at both landbased and above- stream meteorological stations. While the differences between land-based and above-stream observations were broadly similar to those found in previous studies, there were some distinct patterns that were attributed to the timing of daily maximum water temperature, which occurred near midnight rather than early afternoon, as is more typical for non-glacier-fed streams.HydroCouple was applied without calibration under the assumption that bed heat conduction and hyporheic heat exchange were negligible. The model showed good performance (RMSE = 0.30 oC, ME = 0.03 oC) compared to previous literature. Longitudinal advection of the upstream boundary condition had an overwhelming impact on downstream temperatures, leading to low sensitivit…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/85678
note: Process-based modelling of streamtemperature dynamics in a glacially fed riversystembyBilly BrowningB.Sc. Geography, University of Birmingham, UK, 2020A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THEREQUIREMENTS FOR THE DEGREE OFMaster of ScienceinTHE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES(Geography)THE UNIVERSITY OF BRITISH COLUMBIA(Vancouver)August 2023© Billy Browning, 2023The following individuals certify that they have read, and recommend to the Faculty ofGraduate and Postdoctoral Studies for acceptance, the thesis entitled:Process-based modelling of stream temperature dynamics in a glacially fed river systemsubmitted by Billy Browning in partial fulfillment of the requirements forthe degree of Master of Sciencein GeographyExamining committee:Dan R. Moore, Professor, Geography, UBCSupervisorIan McKendry, Professor, Geography, UBCSupervisory Committee MemberAndre Zimmermann, Principal Geomorphologist, Northwest Hydraulics ConsultantsAdditional ExamineriiAbstractGlacially fed streams face increasing threats due to changes in stream temperature andflow from continued glacier recession and climate change. These systems support uniqueecological communities, often highly sensitive to thermal changes. However, understandingthe governing processes of stream temperature in large glacially fed stream reaches remainslimited, with a lack of literature focused on larger rivers with tributaries. The objective ofthis study was to quantify the drivers of stream temperature dynamics in a 24 km long reachof the glacially fed Lillooet River in the southern Coast Mountains, BC.To support the application of HydroCouple, a reach-scale process-based stream tem-perature model, a new stream shading model was developed that used a LiDAR digitalsurface model to simulate shade from riparian vegetation and a conventional DEM to simu-late topographic shade. Based on a comparison with shade interpreted from high-resolutionPlanetScope imagery, the model simulated shade accurately both a…
has type: Thesis/Dissertation
date issued: 2023-11
is shown at: 10.14288/1.0435631
language: eng
degree discipline: Geography
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Moore, R. Daniel
type: Text
identifier URI: http://hdl.handle.net/2429/85678