Groundwater-dependent Terrestrial Ecosystems Research Articles

Groundwater quantitative status assessment for River Basin Management Plan 2022–2027 (RBMP III)

The Groundwater quantitative status assessment is part of River Basin Management Plan 2022–2027 (RBMP III) and is used to evaluate, according to certain criteria, the 21 groundwater bodies (GWBs) in Slovenia. GWB can achieve good or poor quantitative status. The assessment is carried out with four tests, where the impact of groundwater abstraction (pumped quantities) on: groundwater quantity and water balance, the ecological status of associated surface water bodies, groundwater dependent terrestrial ecosystems and the intrusion of saline or poor water quality into the aquifer is analyzed. The final overall assessment of each groundwater body, based on the completed tests, is determined by the criterion of the worst test assessment. Based on the results of the tests, within the assessment period, 20 GWBs in Slovenia achieved good quantitative status. GWB Dravska kotlina achieved poor quantitative status, because the pumping of groundwater causes poor quality water intrusions into the deeper aquifer of that groundwater body. Within the last assessment period 1991–2020, approx. 4 billion m3 of groundwater was available annually in shallow aquifers within groundwater bodies. Groundwater abstraction (pumper quantities) in the period 2014–2019 reached an average of 135 million m3. In the area of deep geothermal aquifers of the Mura basin, abstractions were estimated to sum up to 2.5 million m3 per year. Latest numerical simulations point out induced aquifer recharge of approx. 2.3 million m3 of thermal water.

Source apportionment of nitrogen pressures at a Chalk-fed groundwater-dependent wetland

Abstract In Groundwater-Dependent Terrestrial Ecosystems (GWDTEs), atmospheric nitrogen (N) inputs have often been studied in isolation from terrestrial groundwater and surface water inputs. We describe for the first time the development and application of a combined atmospheric and terrestrial N source apportionment methodology, able to identify contributing catchment and N loadings to GWDTEs. We combined all N inputs using a site-specific conceptual model supported by 12 months’ monitoring for a Chalk-fed GWDTE at Newbald Becksies, East Yorkshire. We discuss implications for effective catchment management, wetland protection and development of a source apportionment methodology. Potential sources of nitrate include: atmospheric deposition, mineralization, leaching from agricultural soils, manure heaps, septic tanks, sewer and mains water leakage. Atmospheric deposition was calculated from measurements of ammonia and nitrogen dioxide concentrations together with rainfall inputs of ammonium and nitrate. Quantification of agricultural sources used the FarmScoper modelling tool to estimate nitrate leaching in the groundwater catchment. Comparison between modelled nitrate concentrations in leachate (15–17 mg N l −1 ) and observed groundwater nitrate concentrations (12.3–19.8 mg N l −1 ) are good. The majority of nitrate is leached from arable land. FarmScoper allows mitigation scenarios to be tested, supporting measures to reduce nitrate within a groundwater catchment.

Historical Loss of Groundwater-Dependent Terrestrial Ecosystems in Undrained and Artificially Drained Landscapes in Denmark

Groundwater-dependent terrestrial ecosystems (GWDTE) have been increasingly under threat due to groundwater depletion globally. Over the past 200 years, there has been severe artificial drainage of low-lying areas in Denmark, leading to a gradual loss of GWDTE nature habitat areas. This study explores the spatial-temporal loss of Danish GWDTE using historical topographic maps. We carry out geographic information systems (GIS) overlap analysis between different historical topographic maps with signatures of GWDTE starting from the 19th century up to a present-day river valley bottom map. We then examine the changes in two protected GWDTE habitat types in different periods and hydrologic spatial locations. Results reveal a decrease in the area of GWDTE over the last 200 years. We attribute this to different human interventions, e.g., drainage, that have impacted the low-lying landscape since the early Middle Ages. We further conclude that downstream parts of the river network have been exposed to less GWDTE habitat loss than upstream ones. This indicates that upstream river valleys are more vulnerable to GWDTE decline. Therefore, as a management measure, caution should be exercised when designing these areas for agriculture activities using artificial drainage and groundwater abstraction, since this may lead to further decline. In contrast, there is a higher potential for establishing constructed wetlands or rewetting peatlands to restore balance.

The importance of early data collection in quarry development consent applications; linking hydrogeological assessment to the decision makers’ legal framework, a case study

The working of superficial deposits frequently interacts with the groundwater table and thus may affect surface water and groundwater dependent terrestrial ecosystems. The Habitats Directive and the Water Framework Directive require detailed consideration of these potential effects during any application for planning consent or other authorizations and during periodic reviews. These assessments need to consider water resources impacts, the potential for pollution and whether the natural water chemistry may be changed in a way that could change ecological conditions. Early recognition of these challenges, and a well-structured hydrogeological investigation programme to properly characterize the site, is essential to facilitate timely progress through the planning process. This case study presents the approach to hydrogeological characterization and assessment used at the proposed Upwood Quarry, Oxfordshire, which is adjacent to a calcareous wetland protected at European level. Through careful characterization and stakeholder engagement, planning consent was obtained. We consider lessons that may be applied to other sites especially with increased regulation of dewatering abstractions and consider the potential impacts of recent court decisions.

Assessing environmental water requirement for groundwater-dependent vegetation in arid inland basins by combining the copula joint distribution function and the dual objective optimization: An application to the Turpan Basin, China

Preserving groundwater-dependent terrestrial ecosystems through environmental water allocation is critical for sustainable development in arid inland basins. Assessing the environmental water requirement is challenging due to the complex relationship between vegetation growth and groundwater depth. This study proposed a new assessment method by combining the copula joint distribution function and the dual objective optimization. The copula joint distribution function was used to describe the relationship between vegetation and groundwater depth instead of the traditional regression analysis. Given an ecological protection target, the conditional probability of achieving the target was estimated using the copula joint distribution. The groundwater depth interval with relatively high probability was suitable for vegetation growth and correspondingly conducive for ecological protection. In addition to ecological protection, the socio-economic water requirement was incorporated into the environmental water assessment, resulting in a dual optimization problem that could be resolved by the ideal point method. The optimization analysis revealed a groundwater depth with a high probability of successful ecological protection and low groundwater evapotranspiration to balance vegetation and human demands for groundwater. The proposed method of environmental water assessment by combing copula joint distribution function and dual objective optimization was applied in the Turpan Basin, an arid inland basin in Northwest China. The environmental groundwater depth ranged between 6 and 20 m, and the optimized interval was 7–8 m. The optimal environmental groundwater depth resulted in a probability of 0.46 to achieve the ecological protection target and annual evapotranspiration of 983 mm. The proposed method was practical and reliable and could be an effective tool for assessing the environmental water requirement of groundwater-dependent vegetation in arid inland basins.

Contribution of local factors to the status of a groundwater dependent terrestrial ecosystem in the transboundary Gauja-Koiva River basin, North-Eastern Europe

A pilot study was carried out in the Matsi spring fen, southern Estonia to test a proposed methodology (Terasmaa et al., 2020) for identifying potential effects of groundwater bodies on groundwater dependent terrestrial ecosystems (GDTE). A comprehensive hydrochemical and isotopic dataset was collected and analyzed using multivariate statistical methods to assess the origin of the groundwater discharging in the spring fen and to determine both the quantitative and qualitative aspects of GDTE-groundwater interdependence. The hydrochemical findings were complemented with the hydrogeological, hydrodynamical and botanical observations, and summarized into a conceptual model of the study site. The results show that the status of the spring fen is influenced both by groundwater inflow from the regional Middle Devonian sandstone aquifer (D2gj-ar) in the transboundary Gauja/Koiva River basin, but also by discharge of the shallow aquifer found in Quaternary (Q) deposits of local extent. By using multivariate statistical methods, the mixing of the two main groundwater sources in the spring fen discharge was quantified. On average, the regional D2gj-ar and local Q aquifer contributed 67% and 33%, respectively, to the spring fen discharge. The groundwater was generally more mineralized in the D2gj-ar aquifer while more nutrient-rich in the shallow Q aquifer. Agricultural activities in the arable lands adjacent to the spring fen have resulted in the elevated loads of macronutrients and halogens in the shallow Q aquifer (Ntot=1.95 ± 2.6 mg N/l, Ptot=0.59 ± 0.8 mg P/l). Although generally in pristine state, the elevated macronutrient loading from the Q aquifer and perhaps the beaver activity, has led to deterioration of the status of the spring fen communities in the upstream parts of the main fen polygon. The N:P ratios were occasionally above the 16:1, indicating nitrogen limitation and phosphorus excess, which is likely due to increased upland loading of phosphorus from fertilizers. The results of the study show that poor chemical status of a GDTE can result from local pollution sources and land-use even in cases when the related regional GW body itself is in good chemical status. Also, the usefulness of analyzing minor groundwater components (e.g Ba, Sr, Al, F, SiO2) in a GDTE assessment in establishing the end-member mixing relationships has been shown. All in all, it is one of the first comprehensive studies of the interactions between a groundwater body and a groundwater-dependent terrestrial ecosystem in the Estonian context.

MAPPING VEGETATION COMMUNITIES INSIDE WETLANDS USING SENTINEL-2 IMAGERY IN IRELAND

Wetlands provide habitat for a wide variety of plant and animal species and contribute significantly to overall biodiversity in Ireland. Despite these known ecosystem services, the total wetland area in Ireland has reduced significantly over the past few decades leading to an ongoing need to protect such environments. The EU Habitats Directive (92/43/EEC) has recognised several wetlands types as “priority” habitats. This study concentrates on a subset of the priority habitats focussing on some groundwater dependent terrestrial ecosystems, (in particular calcareous fens and turloughs), as well as raised bogs. Monitoring these sites across the country by field visits is resource-intensive. Therefore, this study has evaluated remote sensing as a potentially cost-effective tool for monitoring the ecological health of the wetlands. Identification and presence of certain vegetation communities can indicate the condition of the wetland, which can be used for monitoring, for example, activities causing degradation or the progress of restoration attempts. The ecological composition of the wetlands has been analysed using open-source Sentinel-2 data. 10 bands of Sentinel-2 Level-2 data and 3 indices, Normalised Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI) and Normalised Difference Water Index (NDWI) were used to create vegetation maps of each wetland using Bagged Tree (BT) ensemble classifier and graph cut segmentation also known as MAP (maximum a posteriori) estimation. The proposed methodology has been validated on five raised bogs, five turloughs, and three fens at different times during 2017 and 2018 from which three case studies are presented. An overall classification accuracy up to 87% depending on the size of the vegetation community within each wetland has been achieved which suggests that the proposed method is appropriate for wetland health monitoring.

A framework to assess the impact of ecological water conveyance on groundwater-dependent terrestrial ecosystems in arid inland river basins

Overexploitation of water resources at middle reaches has threatened downstream oasis in arid inland river basins. To achieve sustainable development, ecological water conveyance is one effective measure to reallocate water resources between socio-economic and natural systems. A comprehensive impact assessment of ecological water conveyance on groundwater-dependent ecosystems that are common in downstream inland river basins is needed. The present study integrated the technologies of remote sensing analysis, trend detection, and numerical simulation into a technical framework that identifies the spatial response and temporal dynamics of vegetation to groundwater changes induced by ecological water conveyance. The Normalized Difference Vegetation Index (NDVI) was used as a proxy to estimate vegetation. The structure of the framework we used is clear and reasonable. We used remote-sensing data and ground truth information, and a decision tree that incorporates an iterative self-organizing data analysis technique. The decision tree classifies the land cover into affected and unaffected areas, and the results indicate the spatial range of impact. The Mann-Kendall algorithm and Sen's slope detect the tendency in NDVI series that indicates the temporal response of vegetation. The Verhulst logistic function, combined with environment carrying capacity function, constitutes a simplified vegetation dynamic model that can be used to predict potential impact through scenario analysis. An application in the Shiyang River basin in Northwest China evaluated the performance and usefulness of the framework; the accuracy of the results suggested that the framework is effective and practical. Additional case studies are required to assess the reliability and applicability of the framework and identify the factors that affect assessment results beyond our case study in the Shiyang River basin.

Groundwater and connected ecosystems: an overview of groundwater body status assessment in Croatia

BackgroundCroatia, as a Member State of the European Union, has to shape its water policy in accordance with the European Union Water Framework Directive. One of the tasks is to determine whether groundwater are susceptible to anthropogenic changes that would result in a significant surface water status reduction as well as terrestrial and aquatic ecosystems that directly depend on the groundwater.MethodsQuality and quantity data on groundwater and surface water, as well as ecosystems data were collected from multiple sources. Data were analyzed for the selection groundwater associated aquatic and groundwater-dependent ecosystems. Chemical time series data were analyzed and compared with the national guideline limits set by the Croatian water quality standard. The impact of the groundwater abstraction on the groundwater-dependent ecosystem was considered by analyzing the aquifer hydrogeological characteristics, as well as location of the pumping site in relation of the ecosystem, the pumping rate and groundwater level or discharge.ResultsIn karst areas of Croatia, groundwater-dependent aquatic ecosystems are predominant; while in the Pannonian area of Croatia, typically, there are groundwater-dependent terrestrial ecosystems. The status of groundwater bodies was defined as good. The analyzed chemical parameters are at acceptable concentration levels. Groundwater abstraction does not adversely affect most ecosystems. However, many springs that are captured for the water supply dry up in the summer. Given that this is also a common phenomenon at springs not captured, it has to be expected that such environments will be inhabited by organisms that have already adjusted to these conditions. Many different bioindicators have been found to indicate a good chemical and quantitative state of groundwater.ConclusionsTo increase the degree of reliability, research monitoring has been proposed. The monitoring should reduce knowledge gaps including an increase of knowledge of the status of the ecosystems, the definition boundary conditions and threshold values of a good quantitative and qualitative status for individual ecosystems. In future prospects, unavoidable focus has to be climate change that may compromise the availability of groundwater resources.

Vegetation Response to Groundwater Variation in Arid Environments: Visualization of Research Evolution, Synthesis of Response Types, and Estimation of Groundwater Threshold.

Groundwater depth is an important environmental factor affecting vegetation growth and landscape dynamics in arid environments. This study applied a science mapping approach to visualize the development of groundwater-vegetation-related research, synthesized the vegetation response to changes in groundwater depth, and analyzed the change rate of the response curve to identify the groundwater threshold that is essential to conserve the groundwater-dependent terrestrial ecosystems. These ecosystems emerged as a research hotspot due to climate change, groundwater overexploitation, and the recognition of these ecosystems’ importance for sustainable development. There are two main types of response functions of vegetation to changes in groundwater depth—monotone and bell-shaped functions—among which the monotone function includes linear, curvilinear, and stepwise response. The shape of a response curve is mainly determined by the combined effects of oxygen stress, salinization, and water stress; oxygen stress and salinization dominate in shallow groundwater depth, while water stress dominates in deep groundwater depth. On a non-linear vegetation metric—groundwater depth response curve, the change rate analysis method is effective to identify the breakpoint that can be taken as a candidate threshold of groundwater depth. The results will add insight into the intellectual structure of the groundwater-vegetation interactions and provide practical reference for groundwater resource management, ecological conservation, and sustainable development in arid environments.

Environmental Groundwater Depth for Groundwater-Dependent Terrestrial Ecosystems in Arid/Semiarid Regions: A Review.

Groundwater in arid/semiarid regions plays crucial roles in providing drinking water supply, supporting irrigated agriculture, and sustaining important native terrestrial ecosystems. Groundwater depth controls water availability to vegetation and is essential for conserving groundwater-dependent terrestrial ecosystems. Environmental groundwater depth can be defined as a mean depth or a range of depths, satisfying the growth of natural vegetation that is not under stress, either due to lack of water or anoxia or soil salinization. Five methodologies have been reported to estimate environmental groundwater depth: the direct ones rely on response functions that relate vegetation condition, e.g., physiological parameters, appearance frequency, community structure, and remotely sensed physical indexes, to changes in groundwater depth; the indirect one estimates environmental groundwater depth based on the threshold of soil moisture content. To fill a knowledge gap of unique recognized methodology, a conceptual framework was proposed, which involves initial estimation (data collection, response assessment, and estimation) and feedback adjustment (implementation and modification). A key component of the framework is to quantify the linkage between ecological conditions and geohydrological features. This review may provide references for groundwater resources management, ecological conservation, and sustainable development in arid/semiarid regions.

Water Sources of Upland Swamps in Eastern Australia: Implications for System Integrity with Aquifer Interference and a Changing Climate

Temperate Highland Peat Swamps on Sandstone (THPSS) in Eastern Australia are Groundwater Dependent Terrestrial Ecosystems that occur in the headwaters of streams on low relief plateaus. Like upland swamps and peatlands globally, they provide base flow to downstream catchments. However, these swamps are subject to aquifer interference from mining and groundwater extraction and are threatened by urbanization and climate change. We collected winter and summer water samples from swamps in two highland regions of Eastern Australia. Water from the swamps was analyzed for hydrogen (δ2H) and oxygen (δ18O) isotopes and compared with rainwater, surface water and groundwater samples from the surrounding bedrock aquifers to identify likely swamp water sources. Radon (222Rn) was used as an environmental tracer to determine whether the swamps were predominantly groundwater or rainwater fed. Four out of five swamps sampled in the Blue Mountains had greater than 30% of water derived from the surrounding bedrock aquifer, whereas swamps in the Southern Highlands received less than 15% of water from the surrounding aquifer. The water sources for swamps in both regions are controlled by catchment morphology, e.g., valley shape. Understanding water sources of these systems is critical for the determination of likely impacts on THPSS from aquifer interference activities and a changing climate.

Relations between vegetation and water level in groundwater dependent terrestrial ecosystems (GWDTEs)

Alkaline wetlands and fens are groundwater dependent, terrestrial ecosystems (GWDTEs) existing throughout the temperate zone. They contain a large number of protected and endangered plant species and their ecological status is threatened by insufficient groundwater quality and quantity. However, management and conservation of fens are constrained by limited knowledge on the relations between vegetation and measurable hydrological conditions. This study investigates the relations between vegetation and water level dynamics in groundwater dependent wetlands in Denmark.A total of 35 wetland sites across Denmark were included in the study. The sites represent a continuum of wetlands with respect to vegetation and hydrological conditions. Water level was measured continuously using pressure transducers at each site. Metrics expressing different hydrological characteristics, such as mean water level and low and high water level periods, were calculated based on the water level time series. A complete plant species list was recorded in plots covering 78.5m2 at each site. Community metrics such as total number of species and the number of bryophytes were generated from the species lists and Ellenberg Indicator scores of moisture, pH and nutrients were calculated for each site.The water level correlates with the number of typical fen species of vascular plants, whereas bryophytes are closer connected to the stable water level conditions provided by groundwater seepage. The water level variability is proved to be a significant limiting factor for species diversity in wetlands, which should be considered along with the fertility in order to access the habitat quality. The study provides new insight in the water level preferences for GWDTEs which is highly needed in the management and assessment of anthropogenic damage to these ecosystems.

GROUNDWATER STATUS ASSESSMENT IN CONTEXT OF REPORTING REQUIREMENTS TO THE EUROPEAN COMMISSION

The accession of Poland to the European Union and implementation of the Water Framework Directive (2000/60/WE) into the Polish legal system has significantly changed the course and scope of national water management and assessment of water resources. The concept of integrated and dynamic way of treating groundwater and surface waters and their position in the environment, emphasized in the WFD, has strengthened and enhanced the already applied procedures for groundwater monitoring and status assessment. These procedures aim at achieving sensibly justified and well-founded balance between environmental objectives defined for groundwater bo¬dies and water needs required by all types of water users. This required establishment of a new, holistic methods for assessing groundwater body status based on previous national experiences and new EU guidelines and requirements. The new methods for assessing groundwater body status in terms of its quality and quantity were developed and implemented by the Polish Geological Institute – National Research Institute in 2013. The project was commissioned by the Chief Inspectorate for Environmental Protection and financed by the National Fund for Environmental Protection and Water Management. The methods accounts groundwater needs of priority water users through nine classification tests which investigate groundwater characteristics and dependencies between groundwater and its receptors, including surface waters and groundwater-dependent terrestrial ecosystems. Each of nine classification tests can result in either good or poor status and the final groundwater body status assessment is a product of all tests, which means that a negative result of at least one test can decide of poor status of a given groundwater body.

Developing status tests for selected Irish groundwater-dependent terrestrial ecosystem (GWDTE) types as part of groundwater body status assessment under the EU water framework directive

The EU Water Framework Directive (2000/60/EC) requires assessment of the impact of chemical and quantitative groundwater pressures on groundwater-dependent terrestrial ecosystems (GWDTEs). During the first River Basin Cycle (2003–2009), 48 Irish groundwater bodies (GWBs) were identified as at risk of failing to meet the WFD objective of good status owing to potential damage to GWDTEs and required further status assessment. Status tests were only applied to two GWBs, however, owing to the lack of ecohydrogeological data needed to assess damage. This paper aims to contribute to the evaluation of GWDTE chemical and quantitative status and specifically aims to: (1) develop an enhanced understanding of GWDTE ecohydrogeology; (2) determine groundwater nutrient threshold values (TVs) for GWDTEs; and (3) propose methodologies for assessing groundwater-related significant damage at GWDTEs.

In this issue

P R O C E E D I N G S O F T H E R O Y A L I R I S H A C A D E M Y In this issue Bruce Osborne Developing status tests for selected Irish groundwater-dependent terrestrial ecosystem (GWDTE) types as part of groundwater body status assessment under the EU Water Framework Directive Sarah Kimberley and Catherine Coxon Are Ireland’s reintroduced Pinus sylvestris forests floristically analogous to their native counterparts in oceanic north-west Europe? Jenni R. Roche, Fraser J.G. Mitchell, Stephen Waldren and Jørn E. Bjørndalen Population status and factors affecting the productivity of peregrine falcon Falco peregrinus in County Wicklow, Ireland, 2008–2012 Brian J. Burke, Damian Clarke,Ann Fitzpatrick,Tim Carnus and Barry J. McMahon Short Communication: Behaviour of sea lamprey (Petromyzon marinus L.) at man-made obstacles during upriver spawning migration: use of telemetry to assess efficacy of weir modifications for improved passage Seán M. Rooney, Glen Wightman, Ruairi Ó’Conchúir and James J. King Short Communication: Historical change in the European eel population in the Foyle estuary, Northern Ireland J. Barry, K.J. Bodles, P. Boylan and C.E.Adams www.ria.ie ISSN 0791-7945 i 83 97 115 125 137 CONTENTS BIOLOGY ENVIRONMENT and VOLUME 115B Issue 2 (2015) V OL . 115B Scots pine (Pinus sylvestris)© CanStock Photo Inc. B I O L O G Y A N D E N V I RO N M E N T VOLUME 115B Issue 2 (2015) BIOLOGY ENVIRONMENT and RA I N O . 2 (2015) P RO C E E D I N G S O F T H E R OYA L I R I S H A C A D E M Y to print_Layout 1 15/10/2015 11:58 Page 1 IN THIS ISSUE Bruce Osborne Groundwater status Although the sustainable management of water resources is covered through the EU Water Framework directive this does not just cover surface waters, as is often commonly assumed, but also encompasses wetlands and groundwater. Less attention is focused, however, on groundwater reserves, even though much of the water on land is actually derived from groundwater sources. In Ireland 20%25% of our drinking water may come from groundwater sources so contamination of this source could result in significant health issues as well as impacting on the natural biota. This ‘hidden resource’ and its interaction with surface waters have, however, received much needed attention in recent years. Specific measures are also now in place that explicitly cover the prevention and control of groundwater pollution. Significant challenges exist, however, in assessing any deleterious effects on groundwater systems, particularly groundwaterdependent terrestrial ecosystems, such as wetlands, as Kimberley and Coxon, in this issue, indicate. In their paper they report on an assessment of eleven groundwater-dependent ecosystems, including springs, mires, bogs, turloughs, machair and dune slacks, using ecohydrological models and available data. Their objectives included developing an improved understanding of the hydrology of groundwaters but, perhaps more importantly, determining nutrient threshold values that could be used to assess the trophic status of these systems. Unfortunately, because of the paucity of experimental data, accurate assessments of nitrate and phosphate, nutrients that are key factors in determining water quality and trophic status, were not possible. Clearly, a more comprehensive set of experimental data is required before the status of groundwater sources can be predicted with any accuracy. Introduced but no alien impacts? The Scots pine, Pinus sylvestris, is one of our oldest living trees, with one specimen in Finnish Lapland recently dated at 764 years of age. It is also one of the most widespread, and Scots pine has a remarkable ability to tolerate a range of environmental conditions. Based on pollen analyses, it is evident that significant parts of Ireland were formerly covered by this species, and there has been a continuing discussion about whether some of the existing populations are native or have been introduced. Some populations actually look very similar to native populations elsewhere but the consensus is that they have all been re-introduced, as have many populations in the UK, The Netherlands and Denmark, perhaps around 140 years ago. But...

In this issue

P R O C E E D I N G S O F T H E R O Y A L I R I S H A C A D E M Y In this issue Bruce Osborne Developing status tests for selected Irish groundwater-dependent terrestrial ecosystem (GWDTE) types as part of groundwater body status assessment under the EU Water Framework Directive Sarah Kimberley and Catherine Coxon Are Ireland’s reintroduced Pinus sylvestris forests floristically analogous to their native counterparts in oceanic north-west Europe? Jenni R. Roche, Fraser J.G. Mitchell, Stephen Waldren and Jørn E. Bjørndalen Population status and factors affecting the productivity of peregrine falcon Falco peregrinus in County Wicklow, Ireland, 2008–2012 Brian J. Burke, Damian Clarke,Ann Fitzpatrick,Tim Carnus and Barry J. McMahon Short Communication: Behaviour of sea lamprey (Petromyzon marinus L.) at man-made obstacles during upriver spawning migration: use of telemetry to assess efficacy of weir modifications for improved passage Seán M. Rooney, Glen Wightman, Ruairi Ó’Conchúir and James J. King Short Communication: Historical change in the European eel population in the Foyle estuary, Northern Ireland J. Barry, K.J. Bodles, P. Boylan and C.E.Adams www.ria.ie ISSN 0791-7945 i 83 97 115 125 137 CONTENTS BIOLOGY ENVIRONMENT and VOLUME 115B Issue 2 (2015) V OL . 115B Scots pine (Pinus sylvestris)© CanStock Photo Inc. B I O L O G Y A N D E N V I RO N M E N T VOLUME 115B Issue 2 (2015) BIOLOGY ENVIRONMENT and RA I N O . 2 (2015) P RO C E E D I N G S O F T H E R OYA L I R I S H A C A D E M Y to print_Layout 1 15/10/2015 11:58 Page 1 IN THIS ISSUE Bruce Osborne Groundwater status Although the sustainable management of water resources is covered through the EU Water Framework directive this does not just cover surface waters, as is often commonly assumed, but also encompasses wetlands and groundwater. Less attention is focused, however, on groundwater reserves, even though much of the water on land is actually derived from groundwater sources. In Ireland 20%25% of our drinking water may come from groundwater sources so contamination of this source could result in significant health issues as well as impacting on the natural biota. This ‘hidden resource’ and its interaction with surface waters have, however, received much needed attention in recent years. Specific measures are also now in place that explicitly cover the prevention and control of groundwater pollution. Significant challenges exist, however, in assessing any deleterious effects on groundwater systems, particularly groundwaterdependent terrestrial ecosystems, such as wetlands, as Kimberley and Coxon, in this issue, indicate. In their paper they report on an assessment of eleven groundwater-dependent ecosystems, including springs, mires, bogs, turloughs, machair and dune slacks, using ecohydrological models and available data. Their objectives included developing an improved understanding of the hydrology of groundwaters but, perhaps more importantly, determining nutrient threshold values that could be used to assess the trophic status of these systems. Unfortunately, because of the paucity of experimental data, accurate assessments of nitrate and phosphate, nutrients that are key factors in determining water quality and trophic status, were not possible. Clearly, a more comprehensive set of experimental data is required before the status of groundwater sources can be predicted with any accuracy. Introduced but no alien impacts? The Scots pine, Pinus sylvestris, is one of our oldest living trees, with one specimen in Finnish Lapland recently dated at 764 years of age. It is also one of the most widespread, and Scots pine has a remarkable ability to tolerate a range of environmental conditions. Based on pollen analyses, it is evident that significant parts of Ireland were formerly covered by this species, and there has been a continuing discussion about whether some of the existing populations are native or have been introduced. Some populations actually look very similar to native populations elsewhere but the consensus is that they have all been re-introduced, as have many populations in the UK, The Netherlands and Denmark, perhaps around 140 years ago. But...

A new deterministic method for groundwater mapping using a digital elevation model

Accurate knowledge of groundwater levels and flow conditions in the vicinity of groundwater-dependent terrestrial ecosystems (GWDTE-s) is required for identifying groundwater dependency and comparing the present situation with the optimal one, as part of the status assessment of groundwaters according to the EU Water Framework Directive. Geostatistical methods (like kriging or cokriging) may result in an unrealistic groundwater level map if only a few measured data are available. In this paper a new, grid-based, deterministic method (GSGW-model) is introduced. The aim of the model is to calculate groundwater depth within the required accuracy from sparse data of monitoring wells. The basic principle of the GSGW-model is that the groundwater table is a smoothed replica of the ground surface. Hence, changes in the groundwater level between two grid points are calculated as a function of the digital elevation model (DEM) and soil properties. The GSGW-model was tested in the Nyírség region (Hungary). Results were compared with those gained by ordinary kriging and cokriging. It has been concluded that kriging overestimates the groundwater level in the low part of the test area, where wetlands are located, while the maps produced by the GSGW-model are a better fit of the real variability, providing more reliable estimates of groundwater depth in GWDTE-s as well.

Airborne geophysics: a novel approach to assist hydrogeological investigations at groundwater-dependent wetlands

This paper provides an assessment of existing airborne baseline geophysical data in relation to the hydrogeological characterization of protected groundwater-dependent terrestrial ecosystems (wetlands) in Anglesey, Wales. The attenuation of the radiometric data identifies the main areas of water saturation in the very near surface. The radiometric data have the potential to identify additional areas where similar degrees of saturation exist. The data may therefore be used to help define extensions to existing site boundaries and to provide information in the assessment of new wetland areas. The radiometric data also show regional-scale transition from the Carboniferous Limestone in the east, important for water supply to the wetlands, to older more impermeable strata to the west. The conductivity data appear capable of mapping the lateral extent of clay accumulations, concealed below peat cover which can act as a confining layer to the bedrock aquifer. At the regional scale the data reveal the extent of a former Holocene lake system and the hydrogeological control of a Carboniferous limestone–sandstone contact. The data therefore provide a non-invasive spatially continuous, characterization of the sites, improving the understanding of their dynamic water balances and, potentially, guiding further ground assessments and invasive investigations.

Spatio-temporal impact of climate change on the groundwater system

Abstract. Given the importance of groundwater for food production and drinking water supply, but also for the survival of groundwater dependent terrestrial ecosystems (GWDTEs) it is essential to assess the impact of climate change on this freshwater resource. In this paper we study with high temporal and spatial resolution the impact of 28 climate change scenarios on the groundwater system of a lowland catchment in Belgium. Our results show for the scenario period 2070–2101 compared with the reference period 1960–1991, a change in annual groundwater recharge between −20% and +7%. On average annual groundwater recharge decreases 7%. In most scenarios the recharge increases during winter but decreases during summer. The altered recharge patterns cause the groundwater level to decrease significantly from September to January. On average the groundwater level decreases about 7 cm with a standard deviation between the scenarios of 5 cm. Groundwater levels in interfluves and upstream areas are more sensitive to climate change than groundwater levels in the river valley. Groundwater discharge to GWDTEs is expected to decrease during late summer and autumn as much as 10%, though the discharge remains at reference-period level during winter and early spring. As GWDTEs are strongly influenced by temporal dynamics of the groundwater system, close monitoring of groundwater and implementation of adaptive management measures are required to prevent ecological loss.