WATER MANAGEMENT FOR SUSTAINABLE USE AND PROTECTION OF PEATLANDS

Peatlands are common in humid climates and regions with significant rainfall excess. Peatlands cover large areas of northern Europe, and more than 6 % of the land area in Norway. Peatlands are important for water quality and may influence discharge from catchments. In Europe, peatlands have been drained for agriculture, forestry, and peat extraction. The use of peatlands has been important for regional livelihood and development. Peatland drainage may have negative impacts on water resources due to changes in peatland hydrology, increased peat erosion, and leaching of nutrients and organic matter. Greenhouse gas (GHG) emissions, peatland subsidence and peatland fires are also negative impacts of peatland drainage. Peatland management requires careful land and water management to reduce negative impacts on water resources and their ecosystem services (drinking water, recreation, carbon sequestration, water retention etc.). The WATERPEAT project aims to develop the scientific knowledge base on peatlands and water management for different types of peatlands found in peat rich areas of Northern Europe and Indonesia. The Norwegian team has equipped a drained forested mire (Akersmyra, close to Tønsberg) where long-term monitoring data on forest biomass are available and an adjacent pristine reference site (Gjennestadmyra) to examine long-term effects on hydrology and be able to illuminate impacts of hydrology on peatland forest biomass, peatland properties and subsidence. Additionally, development work has been carried out for use of novel methods (digital photogrammetry and Lidar data) aiming at enabling cost-efficient measurements of peatland surface elevation and subsidence (an indicator for peat loss) remotely over large geographical areas and for long time periods. Photogrammetric methods applying digital terrain models and historical aerial photos to measure historical peatland surface elevation levels have been developed and tried out for characterizing historical terrain elevation levels at the peatland Akersmyra, that previously was drained for forestry purpose. Results from this work and terrain elevation data from airborne Llidar measurements were used to compare methods for exploring studies of elevation of peatland surface and illuminate peatland subsidence at Akersmyra due to the drainage of the peatland, and results from previous optical levelling carried out in the afforestation experiment at Akersmyra were examined. The experience from the project indicates that remote sensing of peatland surface elevation is most suitable for open non-forested areas. Limitations for use of photogrammetric methods are connected to access to historical aerial photographs, quality of old photographs and vegetation that restrains vision of the ground. Remote sensing based on Lidar data and / or aerial photographs makes possible high-resolution mapping on large areas of terrain shape on peatlands and shape alterations due to peatland subsidence and other reasons. Depth to the water table and water temperature were registered with hourly intervals in observation wells in the peat at the drained forested peatland Akersmyra and the nearby reference peatland (Gjennestadmyra). Characteristic of the drained peatland was lower peat water table than in the reference mire, most pronounced at low water table, and larger water table fluctuations. Whereas the water table in the wells often was ca. 10-20 cm deeper at Akersmyra than in the reference mire in summer 2021, the water table in summer 2022 was often 20-40 cm lower at Akersmyra than in the reference mire in summer 2022. In both peatlands the water table was lowest in the end of September both in 2021 and 2022. The maximal depth to the water table at the undrained Gjennestadmyra was about 45 cm both in 2021 and 2022. Rapid and large water table fluctuations at high water table can be explained by rapid drainage to the ditches, whereas slow water level lowering in summer periods with deeper water table can be explained by water flux to the forest vegetation roots, showing the importance of vegetation for water table in afforested peatlands and peatland forest management. The temperature of the water in the peat wells ranged from ca. 4 to ca. 10 degrees Celsius at both peatlands.

Data and information on key water quantity and quality processes from experimental sites, a paper on water quality from grasslands public as reported in journal papers. The models DRAINMOD, SWAT and HGS used for peatlands. The SWAT work reported in a PhD thesis and The HGS work will be reported in a PhD thesis at University of Oulu. Use of DRAINMOD was not successful. Studies done on drones remote sensing and airborne photographs. Reporting includes 2 PhD theses at University of Oulu, 2 scientific publications, 3 review papers. The PhD theses are public, the other publications not. A literature review on restoration, water treatment methods and land management options carried out. A report made, but not yet completed. The draft report is available. Pilot tests on mitigation methods carried out. A report on mitigation experiments (leaching control, drainage and runoff water treatments) is public. Two general courses on drainage and one on water management given at University of Oulu. One PhD internal seminar University of Oulu with knowledge generated, Water management in Agriculture and Forestry: Focusing on drainage systems, Agricultural water and nutrient management: novel approaches on water retention and nutrient recycling. A course planned for 2023/2024. Six papers published in leading journals (Science of the Total Environment, Ecological Informatics, Agricultural and Forest Meteorology, Water Resources Research (2 papers), Hydrology Research) and two conference contributions in relevant conferences (EGU General Assembly 2020, AGU 2020 Fall Meeting). Two policy briefs prepared in collaboration with a policy advisory service (ERINN.eu). They will be presented to policymakers (by ERINN) in summer 2023. The majority of this project took place during COVID restrictions, which prevented use of relevant events (e.g. drainage days, water utility days etc.) for communication with stakeholders. The majority of the project took place during COVID restrictions that prevented physical meetings and extensive stakeholder engagement. At the start of the project, the National University of Ireland, Galway partners engaged with Bord na Móna, the major stakeholder for peatlands in Ireland, with a view to understanding the current knowledge gaps in relation to peatland management in Ireland and water quality. 6-monthly meetings were held between the NUIG project team and other stakeholders and experts in this field. The University of Oulu partners arranged a meeting with stakeholders at the kick-off of the project, a Teams meeting seminar was held on peatland issues, and information on the project was sent out. The NIBIO partners discussed with the landowner of the study case and the regional authorities for water environmental protection, talked with stakeholders and sent out information. Methods to monitor, observe and connect the data to internet with better visibility and use of the data by ICT and IoT approaches not applied.

Peatlands are important in several regions as they contribute to many ecosystem services such as drinking water provision, biomass production and flood retention. Peatland drainage leads e.g. to reduced surface water quality, loss in biodiversity and green house gas emission. Peatland water management must consider ways to reduce water-related environmental impacts, produce crops and biomass, limit subsidence and soil loss, prevent fire during droughts, restore and after-use degraded sites. Water management must consider different type of peatlands, different land use options, climate, and socio-economic settings. The potential mitigation options depend on several issues such as land use, peatland type, hydrological setting, climate, geology and the socio-economic setting. Several recommendations for future peatland management have been discussed, suggested and/or required by authorities and NGOs. The options suggested often involve water management with effects on land use and therefore on local communities, land owners and biomass producers. The options outlined should be scientifically sound and tested in practice. Lack of effective, simple and robust water management options to achieve the policy goals result in stakeholders’ frustration, lack of compliance and poor environmental practice guided by an “opportunity driven strategy” rather than “conservation of ecosystem services” approach. This proposal aims to develop the scientific knowledgebase on peatlands and water management for different types of peatlands. A database on peat soil hydrology, water management options and a toolbox on methods for water management will be developed with educational material for capacity building in different regions. This will allow stakeholders to make water management plans on local and catchment scale that meet multiple policy goals and allow a transition for smarter water and land management and suitable solutions to future decision-making.