Utilizing lumped coupled tracer-aided modelling to identify temporal trends in basin-scale evapotranspiration partitioning
| dc.contributor.author | Smith, Aaron | |
| dc.contributor.examiningcommittee | Clark, Shawn (Civil Engineering) Ali, Genevieve (Geological Sciences) Buttle, Jim (School of the Environment, Trent University) | en_US |
| dc.contributor.supervisor | Stadnyk, Tricia (Civil Engineering) | en_US |
| dc.date.accessioned | 2017-10-25T19:14:41Z | |
| dc.date.available | 2017-10-25T19:14:41Z | |
| dc.date.issued | 2015-01-07 | en_US |
| dc.date.issued | 2016-06-21 | en_US |
| dc.degree.discipline | Civil Engineering | en_US |
| dc.degree.level | Doctor of Philosophy (Ph.D.) | en_US |
| dc.description.abstract | Evapotranspiration is a primary hydrologic flux in catchment hydrology, significantly decreasing watershed storage available for discharge. High-latitude watersheds are highly-seasonal where climate change is expected to change sub-surface storage availability, which may consequently result in different evaporation and transpiration fluxes from storages. Temporal variability of the evapotranspiration partitioning in high-latitude large-scale remote watersheds has not been studied but is imperative for assessment of future water availability. Stable water isotopes (SWIs) have been successfully used to separate sources of watershed discharge using both hydrograph separation and modelling techniques as well as evaporative fluxes from total evapotranspiration in small scale modelling studies. The primary objective of this thesis was to identify the temporal changes in evapotranspiration partitioning within high-latitude watersheds, and the influence these fluxes have on watershed storage. A combination of statistical analysis and tracer-aided modelling was used to identify the primary storages contributing to watershed discharge, and the temporal uncertainty of these estimates. Generally, the unsaturated soil zone and rapid overland flow dominated summer discharge, while wetlands and groundwater were the primary contributors during winter. Quantifying temporal contributions of sources and their uncertainties, tracer-aided modelling and hydrograph separation were used to characterize the evaporation fractionation, and thereby evaporation to evapotranspiration (E/ET), within storage to temperature. Model results indicate higher E/ET during spring and fall, annually higher evaporation in wetlands than unsaturated soils, and further increases with soil moisture. Finally, as an additional analysis of the effect of evaporation and transpiration on watershed storage, transit time distributions were used to estimate evaporation and transpiration flux ages. Separating ET into its components using the temperature dependent model revealed similar results to the tracer-aided modelling. Furthermore, mean evaporation age was less than one month, and showed inverse correlation to watershed transit time. Decreases in transpiration age do not directly influence discharge age, however, they resulted in more enriched simulated isotopic composition during the winter. This thesis identifies the importance of evaporation and transpiration fluxes on storage, and provides a framework by which tracer-aided models may be used to identify evaporation and transpiration influences in data-scarce regions. | en_US |
| dc.description.note | February 2018 | en_US |
| dc.identifier.citation | Smith, A., C. Delavau, and T. Stadnyk (2015), Identification of geographical influences and flow regime characteristics using regional water isotope surveys in the lower Nelson River, Canada, Can. Water Resour. J. / Rev. Can. des ressources hydriques, 40(1), 23–35, doi:10.1080/07011784.2014.985512. | en_US |
| dc.identifier.citation | Smith, A., C. Welch, and T. Stadnyk (2016), Assessment of a lumped coupled flow-isotope model in data scarce Boreal catchments, Hydrol. Process., 30(21), 3871–3884, doi:10.1002/hyp.10835. | en_US |
| dc.identifier.uri | http://hdl.handle.net/1993/32676 | |
| dc.language.iso | eng | en_US |
| dc.publisher | Taylor & Francis Online | en_US |
| dc.publisher | Wiley Online | en_US |
| dc.rights | open access | en_US |
| dc.subject | Evapotranspiration partition | en_US |
| dc.subject | Stable Water Isotopes | en_US |
| dc.subject | Tracer-aided modelling | en_US |
| dc.subject | Transit time modelling | en_US |
| dc.subject | Canada | en_US |
| dc.subject | Data scarce | en_US |
| dc.subject | Boreal forest | en_US |
| dc.title | Utilizing lumped coupled tracer-aided modelling to identify temporal trends in basin-scale evapotranspiration partitioning | en_US |
| dc.type | doctoral thesis | en_US |
| local.subject.manitoba | yes | en_US |