Key drivers of stream water quality along an urban-rural transition : a watershed-scale perspective

Detecting trends in stream water quality is one of the key objectives of environmental monitoring. Identifying factors controlling stream water pollutants is challenging due to the diversity of potential sources, pathways, and processes. Natural processes regulating the water quality of a watershed are often affected by anthropogenic activities, resulting in the redistribution of runoff from base flow to storm flow and the introduction of new pollutant sources. Despite the observed consequences of urbanization, a lack of understanding of the factors simultaneously controlling water quality is among the biggest gaps in our current knowledge of hydrogeography. Moreover, prevailing discussions of land-cover effects often neglect the potential contribution of other factors, such as surficial deposits, in stream water concentrations. This thesis aims to 1) examine the most influential watershed properties determining spatial variation in stream water quality; 2) identify key water quality and watershed variables controlling stream biotic responses (i.e. diatom community composition); 3) investigate the effects of multiscale temporal variation on urban runoff in cold climatic regions; and 4) evaluate whether advanced statistical methods are applicable in hydrogeographical modeling of small watersheds. To fulfill these objectives, spatial watershed-scale analyses were conducted using modern non-parametric approaches and theory-driven methods such as structural equation modeling. This thesis is based on unique data sets of both multibasin and multiyear sampling and spatial data from the Helsinki region, southern Finland. A combination of GIS-based approaches and statistical analyses revealed significant links and novel insights into complex relationships between water quality and spatial biogeophysical properties of the surrounding landscape. The importance of land cover was emphasized throughout the thesis. Under base flow conditions the significance of soil type was mainly controlled by land cover. Further, this thesis demonstrates how land cover and stream water quality strongly determine the spatial assemblages of aquatic biota, as elevated pollutant levels were linked to decreased species richness and dominance of more tolerant species of diatom taxa. From a temporal perspective, the results suggest that urban runoff pollution is a chronic phenomenon, and is controlled by both runoff volume (summer) and pollutant sources (winter). Both the divergent temporal behavior and dominant role of diffuse pollution sources indicated challenges for stream water management practices. Based on the observed substance levels, year-round runoff treatment in urban areas is highly recommended. Finally, this thesis increases our knowledge of stream water quality variation in space and time. In this thesis, key local phenomena in contemporary hydrogeography were identified with a spatial modeling framework. The inclusion of indirect effects into the models improved our understanding of these systems, thus emphasizing the importance of simultaneously studying multiple concurrent processes.Yksi ympäristötutkimuksen tärkeimmistä tavoitteista on tunnistaa virtavesien, kuten purojen ja jokien laadun vaihtelu. Tärkeimpien vedenlaatua säätelevien ympäristötekijöiden tunnistaminen on kuitenkin vaikeaa aineiden lukuisten lähteiden, kulkeutumisreittien ja prosessien takia. Ihmistoiminta vaikuttaa myös luonnollisiin vedenlaatua sääteleviin tekijöihin valuma-alueella, muuttaen virtaamaa pohjavalunnasta enemmän sateiden yhteyteen, ja tuottaen uusia haitta-ainelähteitä. Vaikka kaupungistumisen vaikutukset ympäristöön ovat kiistattomia, emme juurikaan tunne eri ympäristötekijöiden yhteisvaikutusta vaikutusta vedenlaatuun. On myös huomionarvoista, että tieteellinen keskustelu maanpeitteen vaikutuksista vedenlaatuun poissulkee usein muiden, kuten maaperätekijöiden vaikutukset virtavesien pitoisuuksiin. Tutkimuksen tavoitteena on 1) tunnistaa virtavesien laadun alueellista vaihtelua vahvimmin säätelevät tekijät 2) tunnistaa tärkeimmät elollisia vedenlaatuindikaattoreita säätelevät valuma-alue- ja vedenlaatutekijät, 3) tutkia kylmän ilmaston kaupungin virtavesien (huleveden) ajallista vaihtelua ja 4) arvioida, voiko nykyaikaisia tilastollisia menetelmiä soveltaa pienten valuma-alueiden alueellisessa mallinnuksessa. Tutkimus perustuu moderneihin ja teorialähtöisiin menetelmiin, kuten rakenneyhtälömalliin. Työssä sovelletaan sekä alueellisesti laajaa että ajallisesti kattavaa mittausaineistoa Helsingin seudulta, Etelä-Suomesta. Työssä käytetyt paikkatietopohjaiset lähestymistavat ja tilastolliset analyysit tuottivat uutta tietoa tärkeistä vedenlaadun ja ympäristötekijöiden monimutkaisista suhteista. Maanpeitteen tärkeys vedenlaatua säätelevänä tekijänä korostui läpi tutkielman. Sateettomana aikana eli pohjavaluntatilanteissa maaperän tärkeys vedenlaadulle oli vahvasti maanpeitteen säätelemä. Tulokset osoittavat, miten sekä maanpeite että vedenlaatu molemmat vaikuttavat virtavesien eliölajirunsauteen. Vesien korkeat ainepitoisuudet olivat suoraan yhteydessä pienempään lajirunsauteen ja enemmän tolerantteihin lajeihin. Ajallisesti tarkasteltuna kaupunkivesien korkeat pitoisuudet ovat jatkuva ongelma viitaten krooniseen ympäristöongelmaan. Pitoisuuksien ajallinen vaihtelu on kesäaikaan vahvasti virtaaman ja talviaikaan ainelähteiden säätelemä. Sekä virtavesien laadun voimakas ajallinen vaihtelu, että hajakuormituksen suuri merkitys ovat merkittäviä haasteita virtavesien kestävälle hallinnalle. Tulosten perusteella kaupunkialueiden hulevedet tarvitsisivat ympärivuotista käsittelyä ennen niiden purkamista muihin vesiin. Lopuksi, työ lisäsi ymmärrystämme virtavesien laadun alueellisesta ja ajallisesta vaihtelusta. Tutkimuksessa tunnistettiin tärkeimmät paikalliset hydrogeografiset ilmiöt soveltaen alueellisen mallintamisen menetelmiä. Epäsuorien vaikutusten tarkastelu lisäsi ymmärrystämme näistä monimutkaisista systeemeistä, korostaen sitä, miten tärkeää on tarkastella useita prosesseja samanaikaisesti

Maankäytön vaikutus pohjoisten alueiden hulevesiin : esimerkkinä Helsingin kaupunkivaluma-alueet

Land use change and urbanisation changes the environment permanently. Due to the development urban hydrology changes; infiltration decreases, surface runoff increases and previously natural state runoff waters are led away from the catchment area with artificial pipelines. Water discharging from the catchment area affects the receiving aquatic ecosystems condition. In this thesis the impact of land use on storm water quality and quantity is being studied with three urban small catchment area in Helsinki. Veräjämäki represents single-family housing and wide green spaces, Pihlajamäki is an area of suburban housing with fragmented green spaces and Itä-Pasila represents an area of intensive land use ja traffic. The focus of the study is to explore the temporal character and annual loads of storm water. The study was held in period of 1.7.2010-2.1.2012. Winter time storm water is examined as well. Sampling site in the discharge point of each catchment area analyzed the water quality and quantity and took samples continually. Samples were analysed for turbidity, conductivity and discharge. In the University of Helsinki's Laboratory of natural geography samples were analysed for content of soluble elements, such as metals and trace elements. Suspended solids and dissolved material were analysed. In the results indicate variation in both between the catchment areas and in temporal scale. In loads and values of conductivity and turbidity there is clear seasonal variation, and spring time melting period and rainy yet mild autumn 2011 are clearly shown. For annual loads Itä-Pasila's intensive land use areas load was clearly the largest among the studied areas. In Pihlajamäki the discharge from the catchment area was unusually large in relation to the area of the catchment and the weather. It is assumed that the volume of runoff is originated from ground water leakage in the catchment area. In Veräjämäki the springtime melting season was clearly shown in loads. When Itä-Pasila's and Pihlajamäki's melting season began early and lasted for very shortly, Veräjämäki's melting period began later and lasted for longer. When observing the land use it was concluded that intensive traffic areas tended to increase the loads and green spaces tended to decrease both loads and discharge. In Itä-Pasila the loads of metals were large and the winter time de-icing of pavements was evidently shown in storm water concentrations of sodium and chloride. Land use was considered to affect the urban storm water unoff on the basis of three studied catchment areas. It affects the volume and timing of runoff as well as the loads.Maankäytön muutos ja urbanisaatio muuttavat ympäristöä pysyvästi. Kehityksen myötä kaupunkialueen hydrologia muuttuu; imeytyminen vähenee, pintavalunta kasvaa ja aikaisemmin luonnontilaiset virtavedet ohjataan pois valuma-alueelta keinotekoisten hulevesiputkien avulla. Alueelta purkautuva vesi vaikuttaa vastaanottavan akvaattisen ekosysteemin tilaan. Työssä tarkastellaan maankäytön merkitystä virtaveden laatuun ja määrään kolmella urbaanilla pienvaluma-alueella Helsingissä. Veräjämäki edustaa pientaloasumista ja viheralueita, Pihlajamäki lähiöasumista ja fragmentoituneita viheralueita, ja Itä-Pasila intensiivisen maankäytön ja vilkkaan liikenteen aluetta. Painopiste tutkimuksessa on ollut tarkastella valuma-alueiden hulevesien temporaalista luonnetta sekä vuosikuormia. Tutkimus suoritettiin jaksolla 1.7.2010-2.1.2012. Työssä tutkitaan myös talvikauden hulevesiä.Valuma-alueiden purkupisteillä sijainneilla näyteasemilla suoritettiin jatkuvatoimista vedenlaadun ja –määrän tarkkailua sekä näytteenottoa. Näytteistä analysoitiin näyteasemilla sameus, johtokyky ja virtaama, ja Helsingin yliopiston luonnonmaantieteen laboratoriossa liukoisia alkuaineita, kuten metalleja ja hivenaineita. Näytteistä analysoitiin myös kiintoaineen ja liuenneen aineen pitoisuudet. Tuloksissa havaitaan sekä valuma-alueiden välistä että temporaalista vaihtelua. Pitoisuuksissa sekä sameuden ja johtokyvyn arvoissa on selvää vuodenaikaisvaihtelua, missä korostuu keväänsulamiskausi sekä sateinen ja leuto syksy 2011. Vuosikuormituksen osalta Itä-Pasilan intensiivisen maankäytön valuma-alueen kuormitus on tutkituista valuma-alueista suurinta. Pihlajamäen valuma-alueelta purkautuva virtaama oli valuma-alueen alaan ja sääolosuhteisiin nähden voimakasta, minkä epäillään aiheutuneen valuma-alueen mahdollisesta pohjavesivuodosta. Veräjämäellä korostui kevään sulamiskauden merkitys kuormituksessa. Kun Itä-Pasilan ja Pihlajamäen sulamiskausi alkoi aikaisin ja kesti ajallisesti vähän, oli Veräjämäen sulamiskausi myöhäisempi ja ajallisesti pidempi. Maankäytön tarkastelussa havaittiin liikennealueiden kasvattavan ainekuormaa ja viheralueiden pääosin pidättävän virtaamaa ja kuormitusta. Itä-Pasilassa metallien huuhtoumat olivat suuria ja talvikauden tiesuolan käyttö kaupunkialueilla vaikutti selvästi kaikkien valuma-alueiden talven ja kevään liukoisen natriumin ja kloridin pitoisuuksiin. Maankäytön todettiin tutkitun kolmen valuma-alueen perusteella vaikuttavan kaupunkialueilta purkautuvan huleveden määrään, virtaaman ajoittumiseen sekä ainekuormaan selvästi

From Rookies To Synthesis: Agile Solutions For Sustainable Doctoral Studies

Modern doctoral education in engineering lies at the intersection of three topical phenomena: firstly, the surge of wicked sustainability concerns and the subsequent burgeoning demand for cross-disciplinarity. Secondly, the rapidly developing new technologies and global knowledge economy provide a thriving problem-solving potential, although – thirdly – this requires proactive and innovative collaboration beyond the scope of a single discipline. Thus, doctoral education needs new practices to ensure that students are equipped with new kinds of competencies to solve unpredictable and wicked sustainability problems. In order to reach these demands, we need to favor collaboration over competition. Here we approach these issues by presenting key findings from a five-year empirical study on doctoral education in engineering. Data were collected by using a journey mapping method on recently graduated doctors in engineering at Aalto University, Finland. Students from the examined research group were compared with a control group. The data were clustered and the main factors contributing to the individual journeys were analyzed. Community, colleagues, and collaboration turned out to have the strongest positive impact on their doctoral journey (average +1.26, scale -3…+3), and they were distributed across the thesis process. Most observations were related to external academic factors, such as funding and journal decisions. Additionally, we present research group practices, such as “Rookies club” and "Synthesis groups" that strengthened students’ resilience and internal support on these factors. These practices initiated positive interdependencies among the students and supported sustainable supervision practices. Our results are applicable to a wide range of doctoral education.Peer reviewe

To Withdraw, Investigate, Negotiate Or Integrate? Students\u27 Coping Strategies With Disorienting Dilemmas In Interdisciplinary Project Courses

In today's rapidly changing and increasingly interconnected world, engineering educators are required to implement active pedagogical approaches to support students' interdisciplinary problem-solving processes. However, interdisciplinary and experiential learning may evoke situations where students question their past learnings and even existing values, beliefs, or assumptions. Our study examined the emergence of “disorienting dilemmas”, a central concept to transformative learning theory, and students' experiences in coping with them in engineering education. We interviewed ten students from two interdisciplinary project courses at School of Engineering in Aalto University, Finland, and conducted thematic analysis to identify the types of disorienting dilemmas and the coping strategies that students employed. Our study found that students experienced disorienting dilemmas related to self-beliefs, approaches to real-world challenges, teamwork, and disciplinary differences. To cope with these dilemmas, we identified four key strategies that reflected different levels of cognitive-behavioral responses: withdrawing, investigating, negotiating, and integrating. Our study contributes to transformative learning theory by extending the understanding of disorienting dilemmas in the context of interdisciplinary project-based education. We also provide practical implications for engineering educators seeking to develop students' competencies to effectively address complex challenges in working life. Effective interventions, such as critical reflection, open discussion, and resolving conflicting perspectives, can help students navigate disorienting dilemmas and enhance their interdisciplinary and transformative learning. Future research can explore how students' team characteristics may affect the emergence of coping strategies identified, as well as investigate the impact of scaffolding on students' learning outcomes.Peer reviewe

Monetary value of urban green space as an ecosystem service provider : A case study of urban runoff management in Finland

The predicted increase in the number of urban flood events can result in substantial monetary losses to society. These costs may be alleviated by preserving ecosystem services, such as urban runoff management. We studied the monetary value of this ecosystem service by applying the replacement cost method in six catchments with varying land-use intensities in two cities in Finland. The economic analysis was based on metric data of urban runoff generation, provided by automatic monitoring stations in the catchments. A hydrological model was applied to estimate evaporation from impervious surfaces, and to simulate runoff in the catchments. Our results suggest that leaving green space unconstructed results in significant monetary savings. The cost of managing runoff correlated with land-use intensity. The ecosystem service value (ESV) was generally higher in catchments with high land-use intensity, low proportion of green space, and high costs of runoff management. Depending on the degree of imperviousness, the ESV ranged from 90,000–270,000 € ha−1. Further, our results suggest that estimates of runoff generation and evaporation are key hydrological factors for assessing ESV. Our study demonstrates how the combination of field data and hydrological and monetary analyses can support regional planning in cold climates.Peer reviewe

Applicability of open rainfall data to event-scale urban rainfall-runoff modelling

Rainfall-runoff simulations in urban environments require meteorological input data with high temporal and spatial resolutions. The availability of precipitation data is constantly increasing due to the shift towards more open data sharing. However, the applicability of such data for urban runoff assessments is often unknown. Here, the feasibility of Finnish Meteorological Institute's open rain gauge and open weather radar data as input sources was studied by conducting Storm Water Management Model simulations at a very small (33.5 ha) urban catchment in Helsinki, Finland. In addition to the open data sources, data were also available from two research gauges, one of them located on-site, and from a research radar. The results confirmed the importance of local precipitation measurements for urban rainfall-runoff simulations, implying the suitability of open gauge data to be largely dictated by the gauge's distance from the catchment. Performance of open radar data with 5 min and 1 km' resolution was acceptable in terms of runoff reproduction, albeit peak flows were constantly and flow volumes often underestimated. Gauge adjustment and advection interpolation were found to improve the quality of the radar data, and at least gauge adjustment should be performed when open radar data are used. Finally, utilizing dual-polarization capabilities of radars has a potential to improve rainfall estimates for high intensity storms although more research is still needed. (C) 2017 Elsevier B.V. All rights reserved.Peer reviewe

Climate change risks pushing one-third of global food production outside the safe climatic space

Food production on our planet is dominantly based on agricultural practices developed during stable Holocene climatic conditions. Although it is widely accepted that climate change perturbs these conditions, no systematic understanding exists on where and how the major risks for entering unprecedented conditions may occur. Here, we address this gap by introducing the concept of safe climatic space (SCS), which incorporates the decisive climatic factors of agricultural production: precipitation, temperature, and aridity. We show that a rapid and unhalted growth of greenhouse gas emissions (SSP5–8.5) could force 31% of the global food crop and 34% of livestock production beyond the SCS by 2081–2100. The most vulnerable areas are South and Southeast Asia and Africa's Sudano-Sahelian Zone, which have low resilience to cope with these changes. Our results underpin the importance of committing to a low-emissions scenario (SSP1–2.6), whereupon the extent of food production facing unprecedented conditions would be a fraction

WAT Thesis: Doctoral Thesis Process Summaries from Water and Environmental Engineering Research Group, 2002–2022

Introduction: The varied ways of getting there This book both celebrates and makes visible the diverse processes that lead to a Doctoral Thesis. We did this by inviting the authors to write so-called “Process Summaries” i.e. short descriptions of the process that ultimately led to their Doctoral Thesis. While writing those summaries, we advised the authors to reflect the most rewarding and challenging parts of the process and to consider what kind of twists and turns the journey entailed. We also asked the authors to think what kind of advice they would like to give now to themselves when they were just starting their thesis work. The result is this collection of Process Summaries and related official Thesis Abstracts. Together, the summaries indicate that completing a Doctoral Thesis is not just one process, but several processes brought together — often along a long and winding road with unforeseen uphills and downhills. Despite this, the Thesis itself describes mainly its scientific contribution, and the related learning and collaborative processes are usually referred to only in a concise and declaratory manner. While this is understandable, it also partly misses the point: as the Process Summaries remind us, the Doctoral Thesis is very much about the diverse ways of “getting there”. By making visible these diverse journeys we feel that this book makes three important contributions. First, the Process Summaries remind us about the importance of collaboration, collegial support, and peer learning — a recurring theme throughout this book. Second, the summaries show very clearly that there is no one “correct” way of carrying out doctoral research, but each path is unique. Thirdly, we hope that the stories documented in this book provide insights and even inspiration for those currently planning or being on the journey of getting there. In that journey, the authors’ encourage us to be active, curious, and brave, to explore and enjoy and, ultimately, to trust in the process and trust in yourself. This book includes a selection of Doctoral Theses that have been completed in the field of water and environmental engineering at Aalto University and its predecessor Helsinki University of Technology from year 2002 until 2022. This, way, the book also celebrates the 20th Anniversary of our Water Building, located at Tietotie 1E in Otaniemi. Thank you to all the contributors! Marko, Maija and Heid

Natural hazards 1990-2015

Natural hazard index contains extreme events which strongly contribute to the interplay of Sosial-Ecological Systems (SES). The natural Hazard data combines cyclones, drought, floods, earthquakes, volcanoes, and landslides. As no reliable time series exists at grid scale, we use a long term average. Global gridded data set with a spatial resolution of 5 arc-min, annual data from 1990 to 2015, and scaled from 0 to 1. Based on: Based on Dilley et al. (2005

The Planet's Stressed River Basins : Too Much Pressure or Too Little Adaptive Capacity?

| openaire: EC/H2020/819202/EU//SOS.aquaterraFreshwater is one of the most critical elements for sustainable development of ecosystems and societies. River basins, concomitant with administrative zones, form a common unit for freshwater management. So far, no comprehensive, global analysis exists that would link the ecological challenges of the planet's river basins to the capacity of the societies to cope with them. We address this gap by performing a geospatial resilience analysis for a global set of 541 river basins. We use the social-ecological systems approach by relating three ecological vulnerability factors (human footprint, natural hazards, and water scarcity) with three adaptive capacity factors (governance, economy, and human development), based on temporal trajectories from 1990 to 2015. Additionally, we examine resilience by subtracting ecological vulnerability from adaptive capacity. The most striking result is the fundamentally different patterns of controlling factors of the resilience in different developing regions, particularly those of Africa and Asia. Their root causes are particularly low adaptive capacity in Africa and high ecological vulnerability in Asia. Alarmingly, the difference between those continents grew within the study period. Finally, this study highlights the rapid dynamics of adaptive capacity in comparison to ecological vulnerability, the latter having more inertia. Their fragile balance is of our interest; they can either support or counteract each other depending on the geographic location.Peer reviewe