Document Type
Thesis
Degree Name
Master of Science (MSc)
Department
Biology
Program Name/Specialization
Integrative Biology
Faculty/School
Faculty of Science
First Advisor
Scott Smith
Advisor Role
Co-Supervisor
Second Advisor
Kevin Stevens
Advisor Role
Co-Supervisor
Third Advisor
Philippe Van Cappellen
Advisor Role
Committee Member
Fourth Advisor
Jim McGeer
Advisor Role
Committee Member
Abstract
Stormwater management ponds (SWMPs) are important aspects of land-use planning and increasingly recognized as active sites of biogeochemical processing that influence carbon cycling; however, little research has investigated the controls on dissolved organic and dissolved inorganic carbon (DOC and DIC) within these systems. This thesis examined the processing and transformations of dissolved carbon between three compartments to support the development of a greenhouse gas (GHG) box-model for urban stormwater ponds, including SWMP sediment, surface water, and vegetation. The objective of this thesis was to assess the biogeochemical processes that govern the rate and transformation of DOC and DIC between these compartments, contextualized through the sources and partitioning of dissolved organic matter (DOM) between different carbon pools. Transformations of carbon between the sediment, surface water, and vegetation were observed through in-situ and laboratory-based experiments for a residential (Activa) and industrial (Wabanaki) SWMP in Kitchener, Ontario, Canada.
Sediment porewater DOC and DIC concentrations were consistently higher and more variable in the inlet forebay (IFB) compared to the main basin (MB) and outlet (OMB), with elevated concentrations observed at Wabanaki compared to Activa. Seasonal patterns were observed and reflected by increased hydrologic inputs and organic matter loading, with higher DOC and DIC concentrations and humic-dominated DOM during spring and fall. Laboratory and in-situ estimates of sediment-water carbon fluxes varied, with in-situ approaches yielding more conservative (i.e., lower-bound) carbon fluxes than lab approaches, related to a decreased concentration gradient between compartments. In-situ approaches provided the most representative assessment of sediment-water carbon exchange and was best suited for GHG modelling. Vegetation composition varied by catchment and influenced DOC leaching dynamics. Aquatic, emergent, and terrestrial plants were used in a laboratory leaching experiment; the terrestrial plant leached 1.3 times and 2.0 times more DOC compared to the emergent and aquatic plants, respectively. When scaled to biomass density, the emergent plant exhibited an estimated DOC flux that was 116 times higher than that of the aquatic plant; however, these estimates did not account for differences in the carbon sequestration potential of these species across plant life stages. Carbon uptake and storage typically increase during periods of growth and peak biomass, while DOC release may increase during senescence and decomposition; therefore, DOC flux estimates from plant leachates may not reflect the net carbon balance of these species over their full lifecycle. Vegetation-derived DOM was of similar composition to upper sediment porewater, influenced by fresh, labile organics. Catchment type, pond design, season, and vegetation presence were identified as being major controls on carbon processing in SWMPs. These findings will be used to inform future GHG models for urban SWMPs and support the development of best management strategies and SWMP design criteria to enable the sequestration of GHGs through stormwater infrastructure.
Recommended Citation
Schmalz, Harper W., "ASSESSING DISSOLVED ORGANIC MATTER SOURCES AND DYNAMICS IN URBAN STORMWATER: IMPLICATIONS FOR GREENHOUSE GASES" (2026). Theses and Dissertations (Comprehensive). 2904.
https://scholars.wlu.ca/etd/2904
Convocation Year
2026
Convocation Season
Spring
App2A - Surface Water Quality Data
App2C_Sediment Survey_2024_results.xlsx (20 kB)
App2C - Sediment Survey Data
App2F_Sediment Data_V0.1.xlsx (95 kB)
App2F - Sediment Porewater Data
App2G - Flux Data.xlsx (41 kB)
App 2G - DOC and DIC Flux Data
App3A_Sediment Core Tables.xlsx (42 kB)
App 3A - Sediment Core Data
App4C_Terrestrial-Vegetation-Survey_V0.1.xlsx (38 kB)
App4C - Terrestrial Vegetation Survey Data
App4D_SAV_Appendix_V0.1.xlsx (23 kB)
App4D - Submerged Aquatic Vegetation Survey Data
App4E_Vegetation Leaching_V0.1.xlsx (25 kB)
App4E - Vegetation Leaching Experiment Data
App4F_SWQ and Porewater_V0.1.xlsx (49 kB)
App4F - Surface Water Quality and Porewater Data
Included in
Biogeochemistry Commons, Civil Engineering Commons, Environmental Chemistry Commons, Environmental Engineering Commons, Water Resource Management Commons, Water Resources Engineering Commons