Assessment of changes in hydrology and water quality in peat dominated catchments due to foreseen changes in bioeconomy-driven landuses

Thesis event information

Date and time of the thesis defence

Place of the thesis defence

Wetteri auditorium (IT115)

Topic of the dissertation

Assessment of changes in hydrology and water quality in peat dominated catchments due to foreseen changes in bioeconomy-driven landuses

Doctoral candidate

MSc Joy Bhattacharjee

Faculty and unit

University of Oulu Graduate School, Faculty of Technology, Water, Energy and Environmental Engineering

Subject of study

Process and Environmental Engineering

Opponent

Professor Annamari Laurén, University of Helsinki

Custos

Professor Professor Bjørn Kløve, University of Oulu

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Assessment of changes in hydrology and water quality in peat dominated catchments due to foreseen changes in bioeconomy-driven landuses

The world is becoming more dependent on a bioresource-based economy to end its reliance on fossil fuels. In Nordic countries, especially in Finland, the increase in biomass production from peatland forestry shows an indication of increased nutrient and suspended solids (SS) exports from the water systems.
The focus of the thesis was to develop new approaches for better evaluating the changing use of bioresources like water resources, considering different socioeconomic conditions and examining the alternative pathways, known as the Nordic Bioeconomy Pathways (NBPs).
This thesis includes four sequential studies to understand the historical and future consequences on hydrology and water quality in the peatland forestry-dominated Simojoki catchment in northern Finland. In the first study, a new algorithm was developed using aerial photos and LIDAR data to identify and generate time series of the ditch networks in different landscapes. The export coefficients used in the second study, with landuses analysed from Landsat and the regional database, provided a clear picture of nutrient loads and SS exports over decades at multiple locations in the catchment. In the third study, integrating the ditch networks in the SWAT hydrological model to identify and calibrate peatland forestry parameters predicted a higher specific loading of nutrients in a clear-cut forest in peat soil than in clear-cut mineral soil. Finally, stakeholders’ opinions, the Finnish forest dynamics model MELA and climate-imposing emission pathways were used to build multiple NBP scenarios for different land system management attributes.
The analysis provided an annual nutrient decrease for sustainability and business-as-usual scenario, whereas, for others, they systematically increased. The results also showed lower variability when climate data was integrated with management forestry attributes. Overall, the new tools and modelling approaches of the thesis can provide direction to focus on the impacts of peatland forestry for the efficient use of bioresources, especially in identifying the spatial zones of excessive loading in a catchment compared to the current condition.
Last updated: 23.11.2022