Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Geography & Environmental Studies

Faculty/School

Faculty of Arts

First Advisor

Michael English

Advisor Role

Dissertation Supervisor

Abstract

Patterns of stream flow in relatively undisturbed Canadian Shield basins are closely linked to their physical and vegetative characteristics and meteorological conditions. The physical characteristics include topography, soil-till composition, depth and structure, slope morphology and bedrock geology. Hydrological flowpaths through, and in-situ chemical processes in the soil-till matrix are influenced greatly by the composition of these features and by the antecedent hydrological conditions preceding a given storm or snowmelt event.

A long term data set, collected by the Dorset Environmental Science Centre, is used to examine eight forested basins within the Muskoka-Haliburton region of south-central Ontario. The basins have a range of physical characteristics representative of this part of the Canadian Shield.

Statistical analysis of streamflow from all basins for approximately 20 years indicates that the response of basins with shallow till is significantly more variable than basins with deeper till. For this data set, streamflow patterns were assessed relative to ambient temperature and precipitation meteorological conditions. This analysis quantifies the differences between annual responses in shallow and deeper tilled basins.

A new approach is taken to quantify antecedent moisture conditions in the study basins. These antecedent moisture conditions are related to precipitation magnitude and basin runoff coefficients. Regression equations quantify these relationships for the study basins and demonstrate significant differences which are related to the physical characteristics of the basin. A daily time series of antecedent moisture conditions constructed for four study basins for four consecutive years explains runoff coefficient patterns in basins with shallow and deep till.

Temporal patterns of dissolved ions, sulphate (SO42-) chloride (Cl-), calcium (Ca2+) and dissolved silica (SiO2) and alkalinity export in surface water were assessed to examine the distribution of these solutes across the range of annual storm events at each site. Storm and spring melt events that are exceeded 20% of the time during the course of a year are responsible for the majority of solute export during a year; however, the relative importance of storm events on solute export differs between deeper and shallow tilled basins and during dry and wet years.

Convocation Year

2008

Download

Share

COinS