Dissolved organic carbon in tropical watersheds : Linking field observation and eco-hydrological modelling
Author
Summary, in English
Data used for this study include land cover maps produced from satellite imagery, daily air temperature and precipitation, digital elevation models (DEMs), water stage, flow, net primary productivity (NPP), soil properties such as total organic carbon (TOC), total nitrogen (TN), cation exchange capacity (CEC), aluminum (Al), iron (Fe), and soil texture within the RRW. Field observations were used to quantify riverine DOC loads, soil water extractable organic carbon (WEOC), DOC in percolation water (pDOC) and leached DOC (LDOC) and to describe their spatial variation and relationships with the aforementioned factors. Statistical models (including simple and quadratic regressions, general linear model, linear mixed effect models) were used to predict DOC within the study area. An eco-hydrological model, the Regional Hydro-Ecological Simulation System (RHESSys), was used to simulate streamflow and link it with stream DOC within the study area. The results of this study show that land use land cover and climate change interact to produce soil WEOC, from which a significant fraction is transported into streams, mainly through overland flow and loaded by the Rukarara River. The riverine DOC loss was low compared to the NPP of the RRW, but may affect the function of both land and water resources with the study area. The RHESSys model detected the response of the watershed to climate variability within the RRW and captured the significant monthly variability in streamflow within the RRW. This result indicates the potential use of RHESSys to estimate streamflow in the RRW and similar tropical watersheds. Stream DOC concentration was explained by simulated streamflow in the natural forest, indicating the potential use of RHESSys model simulated streamflow to predict stream DOC in the study watershed and similar ecosystems. Further studies should evaluate the performance of the RHESSys model to simulate other hydroecological processes in the tropical environment.
Department/s
Publishing year
2019
Language
English
Full text
Document type
Dissertation
Publisher
Lund University, Faculty of Science, Department of Physical Geography and Ecosystem Science
Topic
- Physical Geography
Keywords
- Dissolved organic carbon (DOC)
- Rwanda
- Land use land cover variability
- Climate variability and change
- Rukarara River Watershed
- eco-hydrological modelling
- field observation
Status
Published
Supervisor
ISBN/ISSN/Other
- ISBN: 978-91-985016-2-9
- ISBN: 978-91-985016-1-2
Defence date
23 May 2019
Defence time
13:00
Defence place
Pangea auditorium (room 229), Geocentrum II, Sölveg. 12, Lund
Opponent
- Robert F. Chen (Professor)