The results highlight the value of spatiotemporal rainfall-runoff data and water sampling at a small scale. An important result was that even in small catchments, the spatial variability in the rainfall isotopic composition can be significant and has to be considered for isotope hydrograph separation studies (IHS). Using data from only one rain sampler can result in substantial errors in the estimated pre‐event water (soil and groundwater stored in the catchment) contributions to streamflow. These findings point out that many studies in the literature might contain significant errors and misinterpret underlying physical processes.

In addition, there is a great variety of ways in which climate and catchments interact to produce runoff needs to be further evaluated to draw general conclusions about land use management effects on hydrology catchment with different landscape elements in current and future climates. IHS is a valuable tool that should be applied more widely to understand current and future hydrological processes better.

2009 - present

Off the shell, automatic rain samplers are expensive and closed systems, hindering the advancement in spatiotemporal rainfall-runoff studies (globally). 

To overcome this hindrance, I started during my PhD adapting the "Kennedy" sequential rainfall sampler, which resulted in the Zurich sequential sampler: 

"Zurich sequential sampler, " a low-cost, low-tech rain sampler to collect rainwater samples for stable isotope analysis. The sampler can accurately collect rainwater without mixing with antecedent collected water. Laboratory and field experiments were performed to assess the sampler's performance. The laboratory experiments showed that the sampler can collect high rainfall intensities, and the volume of water in a water sample originating from a different bottle was generally less than 1 ml. The field experiments showed that the average difference between the samplers was less than 1% for the total rainfall amounts and less than 0.3 and 2% for d18O and d2H, respectively. These results suggest that the Zurich sequential sampler is a reliable tool for collecting sequential samples of rainfall for stable isotope analysis and could be used to study the spatial and temporal variability of the isotopic composition of rainfall." 

I am currently developing an updated version, including Arduino and 3D printed components, to improve the sampling quality and spatiotemporal sampling of rainfall-runoff events.

2017-2019

In the AGwit project, I investigate together with Steve Lyon (OSU) and Stefano Manzoni (SU-NATGEO) the effect of biochar in tropical agriculture and its potential to lower impacts on water resources while improving climate change resiliency of irrigated and rainfed tropical agricultural systems. To predict current and future processes in natural or agricultural catchments, it is essential to have comprehensive understanding of water flow paths in the soil‐plant‐atmosphere continuum (SPAC). We investigate this in a literature - meta study which highlights the potential of biochar amendments but also that biochar application does not adhere to a ‘one size fits-all’ paradigm due to a complex interaction of different factors such as (I) production variables, (II) biochar application strategies and (III) site characteristics. Furthermore, we performed a field study with different biochar types in Costa Rica. Stable isotopes of the water (18O and 2H) are used to trace the flow path and to distinguish between different pools of water along the SPAC while drone-based hyperspectral and thermal imagery provide spatial information. This data will be used to inform models and assess how natural vegetation or crops use water resources.

2009 - present

The combination of the Arduino and 3D printing enables to build new flexible and low-cost sensors to measure hydrological processes and collect automatic water samples at an unpresented spatial and temporal scale. One of the projects was to build a controller to operate an automatic water sampler in the field from the office, develop a low-cost 3D-printed water sampler, which was tested in the Tarfala catchment. 

The gained knowledge was used in the teaching method development of the Uppsala University project “TUFF2021 and 2023 - Engaging students in online earth sciences education through windowsill and backyard experiments based on low-cost but high-tech sensors”. The methods consisted of traditional lectures providing theoretical knowledge of high and low-cost sensors and how to assemble and program simple sensors and microcontrollers. Students received an "Arduino-kit" to assemble sensors to be used in simple experiments, pose a scientific question, take ownership of their science experiment and present their work in an online mini-science conference. The approach showed students the long path from sensors, data collection and analysis, and scientific approach and prepared students for future conferences and discussions among peers in a critical way with different topics and results. The developed methods were successfully tested in the new course 1HY210 - Measurement Methods in the Water Sector. The Arduino-kit is easily adjusted and can be used in different BSc to MSc courses and MSc thesis.

2019 - present

In recent pilot projects we performed different spatial distributed snapshot campaigns in the Tarfala catchment, northern Sweden. The collected water samples were analysed on their stable isotope composition and chemical composition (ions, cations, element spectrum, DOC and DIC). We explore the spatial variability of baseflow isotopic composition, how the isotopic signal of the different baseflow elements (e.g., glacier, lake, shallow and deep groundwater storages) contribute within the catchment and downstream region, and whether a newly developed low budget monthly-integrated sample is representative for baseflow monitoring compared to a snapshot sample. Furthermore, we performed multiple infiltration experiments during wet and dry states of the talus slope systems combined with geophysics to explore the subsurface flow path of the water to assess the contribution of groundwater and melting permafrost in streamflow which is currently analysed to present in a manuscript.

Next to natural catchments, I performed different tracer experiments to determine the residence time of water in industrial settling ponds.

2009 - present

The term "hobby projects" sounds silly and amateuristic. Although these projects are usually not funded by seed money, they are great for exploring different topics, testing equipment, or performing experiments to include in research proposals. In additon, they often result in small publications, such as the Mojito anyone, Zuri sequential sampler or How COVID-19 impacted European water education.