Pekka M. Rossi

Environmental tracers and indicators bringing together groundwater, surface water and groundwater-dependent ecosystems: importance of scale in choosing relevant tools

Groundwater–surface water (GW–SW) interactions cover a broad range of hydrogeological and biological processes and are controlled by natural and anthropogenic factors at various spatio-temporal scales, from watershed to hyporheic/hypolentic zone. Understanding these processes is vital in the protection of groundwater-dependent ecosystems increasingly required in water resources legislation across the world. The use of environmental tracers and indicators that are relevant simultaneously for groundwater, surface water and biocenoses–biotope interactions constitutes a powerful tool to succeed in the management task. However, tracer type must be chosen according to the scale of interest and tracer use thus requires a good conceptual understanding of the processes to be evaluated. This paper reviews various GW–SW interaction processes and their drivers and, based on available knowledge, systemises application of conservative tracers and semi-conservative and reactive environmental indicators at different spatial scales. Biocenoses–biotopes relationships are viewed as a possible transition tool between scales. Relation between principal application of the environmental tracers and indicators, examples and guidelines are further proposed for examining GW–SW interactions from a hydrogeological and biological point of view by demonstrating the usability of the tracers/indicators and providing recommendations for the scientific community and decision makers.

Impact of peatland drainage and restoration on esker groundwater resources: modeling future scenarios for management

Esker aquifers are common groundwater bodies in Europe. Management of these aquifers should take account of the sustainability of groundwater-dependent ecosystems and land use in an integrated way. An unconfined esker aquifer in northern Finland was modelled with MODFLOW to determine how groundwater resources are impacted by the surrounding peatland drainage scheme and to simulate scenarios for possible drainage restoration. The impacts of groundwater abstraction and climate change were also simulated. A calibration-constrained Monte Carlo method was used to provide information on the uncertainties associated with model predictions. The results suggest that peatland drainage in the vicinity of eskers can have a significant role in lowering the water table, even though climate variability may mask these impacts. Drainage restoration by filling the ditches might have positive impacts on the aquifer water levels. Comparison of water-table changes caused by peatland drainage with the changes brought by water abstraction and climate variability helped to quantify impacts of different land-use scenarios and facilitated discussion with the local stakeholders. Based on this study, more attention should be devoted to peatland drainage schemes in integrated groundwater management of esker aquifers.RésuméLes aquifères au sein des eskers sont des masses d’eau souterraine communes en Europe. La gestion de ces aquifères doit tenir compte de la durabilité des écosystèmes tributaires des eaux souterraines et de l’utilisation des terres de manière intégrée. Un aquifère libre au sein d’esker dans le nord de la Finlande a été modélisé avec MODFLOW afin de déterminer comme les ressources en eau souterraine sont impactées par les modalités de drainage des tourbières environnantes et pour simuler des scénarios de restauration possible de drainage. Les impacts de prélèvement des eaux souterraines et du changement climatique ont également été simulés. La méthode de calibration Monte Carlo a été utilisée pour fournir une information sur les incertitudes associées aux prévisions du modèle. Les résultats suggèrent que le drainage des tourbières dans le voisinage des eskers peut avoir un rôle significatif sur l’abaissement du niveau phréatique, même si la variabilité climatique peut masquer ces impacts. La restauration du drainage en comblant des fossés peut avoir des impacts positifs sur les niveaux piézométriques de l’aquifère. La comparaison des modifications des niveaux piézométriques causés par le drainage des tourbières avec les modifications induites par les prélèvements en eau souterraine et la variabilité climatique a aidé à quantifier les impacts des différents scénarios d’utilisation des terres et a facilité la discussion avec les parties prenantes locales. A partir de cette étude, plus d’attention devrait être accordée aux modalités de drainage des tourbières dans la gestion intégrée des eaux souterraines des aquifères d’esker.ResumenLos acuíferos en esker son cuerpos comunes de agua subterránea en Europa. El manejo de estos acuíferos debe tener en cuenta la sostenibilidad de los ecosistemas que dependen del agua subterránea y del uso de la tierra de una forma integrada. Se modeló un acuífero esker no confinado en el norte de Finlandia con MODFLOW para determinar como los recursos de agua subterránea son impactados el esquema de drenaje de una turbera circundante y para simular escenarios para una posible restauración del drenaje. También se simularon los impactos de la extracción de agua subterránea y del cambio climático. Se utilizó el método Monte Carlo restringido por el calibrado para proveer información sobre las incertidumbres asociadas con las predicciones del modelo. Los resultados sugieren que el drenaje de turberas en la vecindad de los eskers puede tener un rol significativo en el descenso del nivel freático, aun cuando la variabilidad climática pueda enmascarar estos impactos. La restauración del drenaje mediante el relleno de las zanjas podría tener impactos positivos sobre los niveles de agua del acuífero. La comparación de los cambios en el nivel freático causado por el drenaje de las turberas con los cambios acarreados por la extracción del agua y la variabilidad del clima ayudaron para cuantificar los impactos de diferentes escenarios de uso de la tierra y facilitaron la discusión con los actores locales. Basado en este estudio, se debe dedicar más atención a los esquemas de drenaje de las turberas en un manejo integrado del agua subterránea de los acuíferos eskers.摘要蛇形丘含水层是欧洲常见的地下水体。这些含水层的管理应该综合考虑依赖地下水的生态系统的可持续性和土地利用。采用MODFLOW模拟了芬兰北部一个非承压蛇形丘含水层,以确定地下水资源是怎样受到周围泥炭地排水方案影响的,并模拟了可能排水恢复的各种方案。同时还模拟了地下水抽取和气候变化的影响。采用校准约束的蒙特卡洛法提供了与模型预测相关的不确定性方面的信息。结果表明,蛇形丘附近的泥炭地排水在降低水位中具有重要作用,尽管气候变异可能掩饰着这些影响。通过填充壕沟使排水恢复可能对含水层水位有积极影响。泥炭地排水造成的水位变化与抽水及气候变异导致的变化对比有助于定量不同土地利用方案的影响,促进与当地利益相关人之间的探讨。在本研究的基础上,应该更加注重蛇形丘含水层综合管理中的泥炭地排水。ResumoOs aquíferos esker são massas de água subterrânea comuns na Europa. A gestão destes aquíferos deve ter em conta, de forma integrada, a sustentabilidade dos ecossistemas dependentes de água subterrânea e o uso do solo. Um aquífero esker não confinado no norte da Finlândia foi modelado com o MODFLOW para determinar como os recursos hídricos subterrâneos são afetados na envolvência de um sistema de drenagem de turfeiras e para simular cenários para uma possível restauração da drenagem. Os impactes da captação de águas subterrâneas e de alterações climáticas também foram simulados. O método de Monte Carlo com restrições de calibração foi utilizado para fornecer informações sobre as incertezas associadas às previsões do modelo. Os resultados sugerem que a drenagem das turfeiras na vizinhança de eskers pode ter um papel significativo no rebaixamento do nível freático, apesar da variabilidade climática poder encobrir esses impactes. A restauração da drenagem através do preenchimento das valas pode ter impactes positivos sobre os níveis da água no aquífero. A comparação das variações do nível freático causadas por drenagem de turfeiras com as variações resultantes da captação de água e da variabilidade climática ajudou a quantificar os impactes de diferentes cenários de uso do solo e facilitou a discussão com os atores locais interessados. Com base neste estudo, conclui-se que se deve dedicar mais atenção aos sistemas de drenagem de turfeiras na gestão integrada das águas subterrâneas em aquíferos esker.

The value of scientific information on climate change: a choice experiment on Rokua esker, Finland

This article presents an application of the choice experiment method in order to provide estimates of economic values generated by water quantity improvements in the environment. More importantly, this is the first choice experiment study valuing scientific information and in particular scientific information on climate change. The case study of interest is Rokua in Northern Finland, a groundwater dependent ecosystem very sensitive to climate change and natural variability. The study deals with the uncertainty about the actual dynamics of the system and the effect of future climate change by exploring whether the public values sustained provision of resources for scientific research to better understand long-term environmental changes in Rokua. Data are analysed using a nested multinomial logit and an error component model. Evidence from this study suggests that individuals are willing to pay in order to assure scientific research so as to better understand long-term environmental changes. As a result, policy should consider investing in and supporting related research. Other aspects of water management policy valued by the public are water quantity, recreation, and total land income.

Overview of groundwater sources and water-supply systems, and associated microbial pollution, in Finland, Norway and Iceland

The characteristics of groundwater systems and groundwater contamination in Finland, Norway and Iceland are presented, as they relate to outbreaks of disease. Disparities among the Nordic countries in the approach to providing safe drinking water from groundwater are discussed, and recommendations are given for the future. Groundwater recharge is typically high in autumn or winter months or after snowmelt in the coldest regions. Most inland aquifers are unconfined and therefore vulnerable to pollution, but they are often without much anthropogenic influence and the water quality is good. In coastal zones, previously emplaced marine sediments may confine and protect aquifers to some extent. However, the water quality in these aquifers is highly variable, as the coastal regions are also most influenced by agriculture, sea-water intrusion and urban settlements resulting in challenging conditions for water abstraction and supply. Groundwater is typically extracted from Quaternary deposits for small and medium municipalities, from bedrock for single households, and from surface water for the largest cities, except for Iceland, which relies almost entirely on groundwater for public supply. Managed aquifer recharge, with or without prior water treatment, is widely used in Finland to extend present groundwater resources. Especially at small utilities, groundwater is often supplied without treatment. Despite generally good water quality, microbial contamination has occurred, principally by norovirus and Campylobacter, with larger outbreaks resulting from sewage contamination, cross-connections into drinking water supplies, heavy rainfall events, and ingress of polluted surface water to groundwater.RésuméLes caractéristiques des systèmes aquifères et la contamination des eaux souterraines en Finlande, Norvège et Islande, sont présentées, en lien avec des épidémies de maladies. Les disparités entre ces pays nordiques quant à l’approche utilisée en matière d’approvisionnement en eau potable à partir des eaux souterraines sont discutées, et des recommandations sont formulées pour le futur. La recharge des aquifères est habituellement élevée durant les mois d’automne ou d’hiver ou encore après la fonte des neiges dans les régions les plus froides. La plupart des aquifères continentaux sont libres et donc vulnérables aux pollutions, mais cependant ils sont souvent dépourvus de pressions anthropiques et la qualité de l’eau est bonne. Dans les zones côtières, les sédiments marins déposés précédemment peuvent rendre les aquifères captifs et les protéger dans une certaine mesure. Toutefois, la qualité d’eau de ces aquifères est très variable, du fait que les régions côtières sont également les plus influencées par l’agriculture, les intrusions d’eau de mer et les agglomérations urbaines, ce qui entraîne des conditions difficiles d’exploitation et d’approvisionnement en eau. Les eaux souterraines sont classiquement prélevées dans les dépôts sédimentaires du Quaternaire pour les municipalités de petite et moyenne dimension, dans le socle pour les habitations isolées, et dans les eaux de surface pour les plus grandes villes, à l’exception de l’Islande, où l’alimentation en eau potable repose presque entièrement sur les eaux souterraines. La gestion des aquifères par recharge artificielle, avec ou sans traitement préalable de l’eau, est largement répandue en Finlande afin d’accroître les ressources actuelles d’eau souterraine. En particulier pour les petits services d’adduction, l’eau souterraine est souvent distribuée sans traitement. Malgré la bonne qualité de l’eau en général, des contaminations microbiennes sont principalement causées par des norovirus et la bactérie Campylobacter, avec des épidémies plus importantes résultant d’une contamination par des eaux usées, des interactions avec les réseaux de distribution de l’eau potable, des événements pluvieux intenses, et des infiltrations d’eaux de surface contaminées vers les eaux souterraines.ResumenSe presentan las características de los sistemas de agua subterránea y de su contaminación en Finlandia, Noruega e Islandia, así como su relación con brotes de enfermedades. Se discuten las disparidades entre los países nórdicos en cuanto al enfoque para proveer agua potable segura a partir del agua subterránea y se dan recomendaciones para el futuro. La recarga de agua subterránea suele ser alta en los meses de otoño o invierno o después de la deshielo en las regiones más frías. La mayoría de los acuíferos continentales no están confinados y por lo tanto son vulnerables a la contaminación, pero a menudo carecen de mucha influencia antropogénica y la calidad del agua es buena. En las zonas costeras, los sedimentos marinos previamente emplazados pueden estar confinados y proteger hasta cierto punto a los acuíferos. Sin embargo, la calidad del agua en estos acuíferos es muy variable, ya que las regiones costeras también están más influenciadas por la agricultura, la intrusión de agua de mar y los asentamientos urbanos, resultando condiciones desafiantes para la captación y suministro de agua. El agua subterránea se extrae típicamente a partir de los depósitos del Cuaternario en los municipios pequeños y medianos, a partir de la roca de base en los hogares unifamiliares, y a partir del agua superficial en las ciudades más grandes, a excepción de Islandia, que depende casi enteramente de agua subterránea para el suministro público. La gestión de la recarga de acuíferos, con o sin tratamiento previo de agua, es ampliamente utilizada en Finlandia para extender los recursos actuales del agua subterránea. Especialmente en pequeñas empresas de servicios públicos, a menudo se suministra agua subterránea sin tratamiento. A pesar de la buena calidad del agua en general, la contaminación microbiana ha ocurrido, principalmente por norovirus y Campylobacter, con los brotes más grandes como resultado de la contaminación a partir de las aguas residuales, conexiones cruzadas en el suministro de agua potable, fuertes lluvias y el ingreso de agua superficial contaminada al agua subterránea.摘要本文展示了芬兰、挪威和冰岛地下水系统和地下水污染的特征,因为这些特征与疾病的爆发密切相关。论述了北欧国家在从地下水中提供安全饮用水方法中各国之间的差异,并为将来提供了建议。地下水补给在秋天和冬季或者最寒冷地区雪融之后通常很高。最内陆含水层为非承压含水层,因此,容易受到污染,但一般没有很大的人为影响,水质很好。在沿海地区,先前沉积的海相沉积物可能承压,在一定程度上保护含水层。然而,这些含水层的水质变化很大,因为沿海地区也受到农业、海水入侵和城市定居点极大影响,导致抽水和供水面临挑战。通常从第四纪沉积层中抽取地下水用于中小城市,从基岩层抽水用于家庭以及从地表水抽取用于最大的城市,冰岛是个例外,冰岛几乎完全依赖地下水用于公共供水。管理的含水层补给,无论是否经过水处理,在芬兰得到广泛应用,目的就是扩大目前的地下水资源。特别是在小的公共事业上,通常提供的地下水没有经过处理。尽管总的来说水质良好,但已经发生过微生物污染,主要是由诺洛病毒和弯曲杆菌导致的,还由于下水道污染、连通到饮用水供水、暴雨事件及污染的地表水进入地下水引起过较大的爆发。ResumoAs características dos sistemas de águas subterrâneas e contaminações subterrâneas na Finlândia, Noruega e Islândia são apresentadas, uma vez que estão relacionados com surtos de doenças. Disparidades entre os países Nórdicos na abordagem de fornecimento de água potável segura dos aquíferos são discutidas e fornecidas recomendações futuras. A recarga das águas subterrâneas é tipicamente mais elevada nos meses de outono ou inverno, ou após o desgelo das regiões mais frias. A maior parte dos aquíferos do interior são confinados e, portanto, vulneráveis à poluição, mas existe pouca interferência antrópica e qualidade da água é considerada boa. Na zona costeira, os sedimentos marinhos previamente depositados podem confinar e proteger os aquíferos até certo ponto. Entretanto, a qualidade da água nesses aquíferos é altamente variável, uma vez que as regiões costeiras também são mais influenciadas pela agricultura, intrusão de água salina e assentamentos urbanos, resultando em condições desafiadoras para a captação e abastecimento de água. As águas subterrâneas são comumente extraídas de depósitos Quaternários para pequenas e médias cidades, do maciço rochoso para residências individuais, e das águas superficiais para grandes cidades, com exceção da Islândia, que depende quase inteiramente das águas subterrâneas para abastecimento público. O gerenciamento da recarga de aquíferos, com ou sem tratamento prévio da água, é amplamente utilizado na Finlândia para preservar os recursos hídricos. Especialmente em pequenas cidades, a água subterrânea é fornecida sem tratamento. Apesar da boa qualidade da água de um modo geral, a contaminação microbiana tem ocorrido principalmente por norovírus e Campylobacter, com surtos maiores resultantes da contaminação de esgotos, ligações cruzadas no abastecimento de água potável, eventos de chuvas intensas e intrusão de águas superficiais poluídas nas águas subterrâneas.

Does habitat restoration enhance spring biodiversity and ecosystem functions

Degradation of groundwater-dependent ecosystems has raised a need for their restoration, but ecological responses to restoration are largely unknown. We evaluated the effectiveness of spring restoration using data from near-natural, restored, and human-impacted springs, the major impact being degradation of spring hydrology by forest drainage. We used both taxonomic (bryophytes, macroinvertebrates, and leaf-decomposing fungi) and functional (leaf breakdown) measures of restoration success. We expected that by reducing surface water input, restoration will improve spring hydrology and place spring ecosystems in a trajectory towards more natural conditions. Restored springs were thermally more stable than impacted springs and the contribution of surface water was greatly reduced. Bryophytes were more abundant in restored than in impacted springs but did not differ among restored and natural springs. Similarly, macroinvertebrate communities differed between restored and impacted springs whereas no difference was detected between restored and natural sites. Species diversity and functional attributes showed weaker responses to restoration. Our results suggest that restoration enhances spring habitat quality, and the first signs of biodiversity enhancement were also detectable only a few years post-restoration. Restoration clearly bears great promise as a conservation tool for the protection of this valuable component of regional freshwater biodiversity.

The Contribution of Non-Use Values to Inform the Management of Groundwater Systems: The Rokua Esker, Northern Finland

Rokua in Northern Finland is a groundwater dependent ecosystem very sensitive to climate change and natural variability. As such, the water level of most of the lakes is a function of the level of the groundwater table of the esker which is naturally recharged. The management of an ecosystem like this is very challenging and complex because of the many associated use and non-use values. The scope of this study is to expose, apart from the use values, the nonmarket values attached to the ecosystems services of groundwater systems and reveal their importance. In particular, this chapter illustrates the contribution of stated preference methods to orient policy making and presents results from an application of a choice experiment and contingent valuation method regarding ground water quantity. General public�s elicited values highlight the importance of water management policy which contributes to the sustainability of groundwater dependent ecosystems. Importantly results highlight the need to broaden the policy options beyond the consideration of market and use values of groundwater systems. Instead these systems should be considered as part of the broader ecosystems and broader services considered in decision making.

Quantifying spatial groundwater dependence in peatlands through a distributed isotope mass balance approach

The unique biodiversity and plant composition of peatlands rely on a mix of different water sources: precipitation, runoff and groundwater (GW). Methods used to delineate areas of ecosystem groundwater dependence, such as vegetation mapping and solute tracer studies, are indirect and lack the potential to assess temporal changes in hydrology, information needed in GW management. This paper outlines a new methodology for mapping groundwater-dependent areas (GDAs) in peatlands using a 2H and 18O isotope mass balance method. The approach reconstructs the initial isotopic composition of the peat pore water in the uppermost peat layer before its modification by evaporation. It was assumed that pore water in this layer subject to evaporation is a two-component mixture consisting of GW and precipitation input from the month preceding the sampling period. A Bayesian Monte Carlo isotope mixing model was applied to calculate the proportions of GW and rainwater in the sampled pore water and to assess uncertainties. The approach revealed large spatial variability in the contribution of GW to the pore water present in the top layer of peatland, covering the range from approximately 0 to 100%. Results show that the current GW protection zones determined by Finnish legislation do not cover the GDAs in peatlands and highlight a need for better classification of groundwater-dependent ecosystems and conceptualisation of aquifer-ecosystem interactions. Our approach offers an efficient tool for mapping GDAs and quantifying the contribution of GW to peatland pore water. However, more studies are needed to test the method for different peatland types. This article is protected by copyright. All rights reserved.

Groundwater contamination and land drainage induce divergent responses in boreal spring ecosystems

Degradation of freshwater ecosystems has engendered legislative mandates for the protection and management of surface waters while groundwater-dependent ecosystems (GDEs) have received much less attention. This is so despite biodiversity and functioning of GDEs are currently threatened by several anthropogenic stressors, particularly intensified land use and groundwater contamination. We assessed the impacts of land drainage (increased input of dissolved organic carbon, DOC, from peatland drainage) and impaired groundwater chemical quality (NO3--N enrichment from agricultural or urban land use) on biodiversity and ecosystem functioning in 20 southern Finnish cold-water springs using several taxonomic and functional measures. Groundwater contamination decreased macroinvertebrate and bacterial diversity and altered their community composition. Changes in macroinvertebrate and bacterial communities along the gradient of water-quality impairment were caused by the replacement of native with new taxa rather than by mere disappearance of some of the original taxa. Also species richness of habitat specialist (but not headwater generalist) bryophytes decreased due to impaired groundwater quality. Periphyton accrual rate showed a subsidy-stress response to elevated nitrate concentrations, with peak values at around 2500 μg L-1, while drainage-induced spring water brownification (increased DOC) reduced both periphyton accrual and leaf decomposition rates already at very low concentrations. Our results highlight the underutilized potential of ecosystem-level functional measures in GDE bioassessment as they seem to respond to the first signs of spring ecosystem impairment, at least for the anthropogenic stressors studied by us.

How to Earn the Status of Honest Broker? Scientists’ Roles Facilitating the Political Water Supply Decision-Making Process

ABSTRACT “Honest broker” refers to scientists facilitating complex political decisions from a neutral position, aiming to expand the scope of choice available instead of advocating a certain policy. This article reflects on the experiences of three scientists acting as honest brokers while carrying out a multicriteria evaluation to help politicians choose the water supply option for the city of Oulu, Finland. The process was considered successful and many politicians said that they have never before been that well informed when making a decision. The case primarily shows that besides the common knowledge brokerage roles targeting knowledge exchange, the honest brokerage approach relates more to managing social relationships and balancing political games and rapidly evolving discussions. Trustful relationships increased the perceived credibility of the brokers and ensured two-way communication. On the other hand, the brokers faced ethical dilemmas and difficulties of staying impartial while finding out confidential information related to political strategies.

UAV Remote Sensing Surveillance of a Mine Tailings Impoundment in Sub-Arctic Conditions

Mining typically involves extensive areas where environmental monitoring is spatially sporadic. New remote sensing techniques and platforms such as Structure from Motion (SfM) and unmanned aerial vehicles (UAVs) may offer one solution for more comprehensive and spatially continuous measurements. We conducted UAV campaigns in three consecutive summers (2015–2017) at a sub-Arctic mining site where production was temporarily suspended. The aim was to monitor a 0.5 km2 tailings impoundment and measure potential subsidence of tailings. SfM photogrammetry was used to produce yearly topographical models of the tailings surface, which allowed the amount of surface displacement between years to be tracked. Ground checkpoints surveyed in stable areas of the impoundment were utilized in assessing the vertical accuracy of the models. Observed surface displacements were linked to a combination of erosion, tailings settlement, and possible compaction of the peat layer underlying the tailings. The accuracy obtained indicated that UAV-assisted monitoring of tailings impoundments is sufficiently accurate for supporting impoundment management operations and for tracking surface displacements in the decimeter range.