Abstract The Palaeaux project has brought together up-to-date geochemical, isotopic and hydrogeological information on coastal groundwaters across Europe in a transect from the Baltic to the Canary Islands. These data have been interpreted in relation to past climatic and environmental conditions, as well as extending and challenging concepts about the evolution of groundwater near the present day coastlines. Groundwater movement beyond the present coastline as well as emplacement on shore to greater depths (up to 500 m) than allowed by the present-day flow regime has occurred, hence offshore freshwater reserves are inferred in some coastal areas. The main attributes of palaeowaters, in terms of water quality, are their high bacterial purity, total mineralization that is often less than that of modem waters and being demonstrably free of anthropogenic chemicals. However, in the Mediterranean coastal areas, lower recharge leads to higher salinity conditions in both palaeo- and modem waters. Freshwater of high quality originating from different climatic conditions to the present day, when the sea level was much lower, is found at depth beneath the present-day coastline in several countries. Recharge is shown to have been more or less continuous during the past 100 ka, even beneath the ice, as demonstrated by groundwaters from Estonia, having δ 18 O values of c. −22%. However, elsewhere (UK and Belgium) an age gap can be recognized indicating that no recharge took place at the time of the last glacial maximum. Devensian recharge temperatures (soil air temperatures) were some 6°C colder across Europe than at the present day. The development of aquifers in Europe during the past 50–100 a, by abstraction from boreholes, has generally disturbed flow systems that have evolved over varying geological timescales, especially those derived from the Late Pleistocene and Holocene. Hydrogeophysical logging has demonstrated time and quality stratified aquifers resulting in mixed waters being produced on pumping. A range of specific indicators, including 3 H, 3 H/ 3 He, 85 Kr, chlorofluorocarbons and pollutants, have been used to recognize the extent to which waters from the modern (industrial) era have penetrated into the aquifers, often replacing the natural palaeogroundwaters. In the coastal regions, many problems for management are identified, including issues relating to quantity and quality of water, seasonal demand, pollution risks and ecosystem damage, requiring a new look at legislation.

Abstract A strongly depleted stable isotope composition, absence of 3 H and a low radiocarbon concentration are the main indicators of glacial origin of groundwater in the Cambrian–Vendian aquifer in northern Estonia. It is concluded from noble gas analyses that palaeorecharge occurred at temperatures c. 0°C. In some wells unexpectedly high gas concentrations have been found. Excess air, up to c. 50 %, is common but two-five times oversaturation is very unusual, requiting special processes and explanations, e.g. oversaturation may indicate recharge under high-pressure conditions, perhaps by subglacial meltwater recharge through the aquifers. Analyses of the gas composition in some groundwater samples also showed a rather high concentration of CH 4 , indicating the influence of biogenic reactions in the subsurface that could cause the rather negative δ 13 C values. Results of δ 13 C analyses in two CH 4 samples also show that the CH 4 is most likely of a biogenic origin. Based on the isotope data, the results of noble gas analyses, and considering the palaeoclimatic and palaeoenvironmental situation in Estonia during the late Weichselian time, it is concluded that palaeorecharge of Cambrian–Vendian aquifer most probably occurred during the last glaciation, probably by subglacial drainage through the tunnel valleys.

Abstract The Ribe Formation is a regionally extensive Miocene sand aquifer that is present in western Denmark at depths ranging from 100 to 300 m below ground surface. Groundwater chemistry and isotope data collected from more than 40 wells show that the Ribe Formation mainly contains high quality Ca-bicarbonate type groundwater of Holocene age (100–10 000 a bp ). Pleistocene age groundwaters, identified on the basis of stable isotopes, noble gases and corrected 14 C values, are present below the island of Rømø, in discharge areas near the coast, and in hydraulically isolated inland areas. The groundwater age distribution in the Ribe Formation was successfully simulated with a numerical groundwater flow model and particle tracking only when the 14 C content in groundwater was corrected for both geochemical reactions and diffusion. The results indicate that geochemical and physical processes significantly influence the 14 C content of groundwater and that the correction factors required for the two processes are of the same magnitude. Flow modelling results indicate that Pleistocene groundwaters were emplaced at depth within the Ribe Fromation under low base-level conditions that prevailed throughout the late Pleistocene – near the coast these waters are essentially isolated from the present flow system, and Pleistocene freshwater may be present offshore. Seismic surveys show that conditions offshore are favourable for the presence of Pleistocene freshwater within the Ribe Formation and other aquifers.

Abstract The Ledo-Paniselian aquifer presents a case study of evolution of fresh groundwater from sea water under the changing piezometric and climatic conditions of the Pleistocene and Holocene. Hydrogeochemical, isotopic, experimental and hydrodynamic results are used in the interpretation. The distribution of groundwater types in the Ledo-Paniselian aquifer is determined by two end members: fresh Ca-HCO 3 recharge water and sea water-saturated sediments. Hydrogeochemical modelling supports the view that mixing of the end members and cation exchange are the main processes; calcite dissolution is also important. Cation exchange consists, in the first place, of desorption of the adsorbed marine cations (Na + , K + and Mg 2+ ) in exchange for the freshwater cation Ca 2+ . Groundwater δ 18 O is around the value of modem precipitation in the area (−6.5‰) for the samples with higher radiocarbon contents; it is < −7.0‰ for the groundwater containing the lowest radiocarbon levels. An overlapping transition zone exists between both groups. δ 13 C becomes heavier for the samples containing the lowest radiocarbon levels, indicating chemical dilution. Pore waters from the Bartonian clay show preferential flow paths. Faster flow paths are more strongly leached, leading to low total dissolved solids (TDS), low sulphate concentrations and low Mg 2+ /Ca 2+ ratios; the slower pathways still contain gypsum, increasing the sulphate concentrations and TDS, and Mg 2+ /Ca 2+ ratios are higher because they were less reduced by cation exchange resulting from freshening. Four methods for determining cation exchange capacity (CEC) and adsorbed cations are compared: the NH 4 OAc method, two BaCl 2 methods (one in unbuffered and the other in buffered conditions) and a new NaCl/NH 4 Cl method. Reasonable CEC values are obtained with the NH 4 OAc method. Comparing the measured equivalent fractions of the adsorbed cations with those calculated from the pore solutions, using the computer programme PHREEQC, it can be concluded that the NaCl/NH 4 Cl method produces the best results. The proton exchange capacity of decalcified sand from the Ledo-Paniselian aquifer was determined to be c. 1−1.5 meq/100 g in the pH range 5–8.5. A hydrodynamic model is developed to explain the evolution of groundwater and for evaluating the effects of pumping at both local and regional scales. Model calculations show that the observed freshwater-saltwater distribution is not the result of the present freshwater flow conditions but the result of different flow regimes during the ice ages when sea levels were much lower. Occurrence of a permafrost layer during cold periods could have had a dramatic impact on the groundwater flow system by, at least temporarily, decreasing the recharge of the aquifers. The existence of the Saalian ice sheet in The Netherlands could have influenced the flow in the deeper Eocene-Oligocene aquifers. The high pressures that existed under the ice sheet could have reversed the flow direction from north to south.

Abstract The marked climatic changes that occurred during the Late Quaternary and Holocene have had a significant impact on the evolution of the groundwater systems at and near the English coastline. Lowered sea levels and the emergence of a much larger landmass over most of the past 100 ka have also ensured deeper groundwater circulation in the vicinity of the modern coastline. The impacts on the Chalk and Lower Greensand (Albian) aquifers along the English Channel and North Sea coasts are examined, using mainly geochemical and isotopic evidence, especially from borehole depth profiles and interstitial waters. Along the south coast, fresh groundwaters are found to depths of 250–300 m below OD (ordnance datum) in the Brighton–Worthing area, as well as beneath Poole Harbour, which are related to deeper circulation during lowered sea levels, controlled by the central palaeovalley of the English Channel. In contrast, pockets of saline groundwater are found, protected in east–west structures, which are considered to be little-modified Chalk formation waters. In the Albian sands, near Worthing, freshwaters dating to 7 ka bp are found at a depth of −450 m OD, suggesting that movement of groundwater towards the shoreline and possibly beyond is still occurring. The east–west structures also influence groundwater migration in north Kent, where fresh palaeowaters can be identified beneath saline water which invaded during the Holocene sea-level rise. In the East Midlands Sherwood Sandstone aquifer, freshwater is found to a depth of −500 m OD, showing continuous geochemical evolution probably over a period of 100 ka, although an ‘age gap’ of between c . 20 and 10 ka bp corresponds to permafrost cover. These palaeowaters in coastal and near-coastal areas remain effectively isolated from the active present-day meteoric flow system but represent high-value resources that may, in some cases, extend offshore.

Abstract Over time, coastal aquifers, which constitute a great part of available freshwater resources from sedimentary basins in France, have been subjected to changes in hydraulic gradients and hydrodynamic properties, mainly due to discharge–recharge phases in response to sea-level variations and/or human influences. This work aims to understand the salinization process originating from the recharge–discharge conditions as recognized at three sites: the calcareous Dogger aquifers along the English Channel (Caen area); along the Atlantic coast (Marais Poitevin), and the Astian sandy aquifer (Cap d’Agde). In addition to conventional hydrogeological and hydrochemical techniques, the main tools used for investigation are those of isotope geochemistry. For the three study sites, the evolution of isotopic signatures along a flow path, depending on the mineralogy of the aquifer matrix, is linked to water–rock interactions such as cation exchange and equilibrium with aluminosilicates. Residence times of these fresh groundwaters are from Modern (Atlantic site) up to the 14 C detection limit (English Channel site). Groundwater of the Astian aquifer (Mediterranean) belongs to the Holocene, as determined by 14 C analyses. The saline waters identified in the three study sites have a marine origin and were modified either by interaction with organic-rich layers, by cation exchange, or by deep carbon input. The salinization process has been associated with marine overflow onto a plain and to an upward leakage of water rich in CO 2 . The marine intrusion registered in the English Channel and Atlantic aquifers is associated with the Flandrian transgression; for the Astian aquifer, the salinization is related to mixing with older water.

Abstract In the framework of the PALAEAUX project, three coastal aquifers have been studied in Spain, looking at the possible existence of Pleistocene or Early Holocene fresh groundwater, in addition to the formerly studied Llobregat Delta. They constitute representative situations of the most common coastal aquifers. The main characteristics of these four areas are: The Llobregat Delta system, studied since 1965, is placed to the southwest of Barcelona (NE Mediterranean coast of the Iberian Peninsula). It is a sedimentary fluvial formation of Pleistocene to recent age, which is representative of small size coastal alluvial formations with the deep confined aquifer open to the sea offshore. Marine sea water penetrated the deep Pleistocene layer during the Flandrian sea-level rise but afterwards relatively high freshwater heads upstream allowed its progressive flushing to the sea through the submarine outlet since 6000–8000 a ago. Freshwater turnover time is shorter than the Holocene duration and it has been renovated due to natural discharge of the aquifer to the sea. The renovation process has recently been accelerated due to intensive groundwater exploitation during the past century. Nowadays, only freshwater a few centuries old remains in low permeability areas of the confined Pleistocene aquifer. The Doñana sedimentary aquifer system corresponds to the ancient estuary of the Guadalquivir River (SW Spain). It contains old saline groundwater that has not been flushed away due to the low freshwater head. In this aquifer 39 Ar, 85 Kr, 3 H, 14 C and 13 C measurements have been used to ascertain the age structure of several mixed groundwater samples. After correction, the oldest fresh groundwater 14 C age is c . 12–15 ka but 39 Ar ages point to somewhat younger water. Neither the stable isotope contents nor the recharge temperature calculated from noble gases show a climatic signature for these waters. The Inca-Sa Pobla carbonate system is the northeast sector of the island of Mallorca. Brackish and salt groundwater in the coastal area has been found along the coastal strip of S’Albufera, displaying what seems a convective-like flow pattern inside the up to 200 m thick aquifer. The most consistent estimated average 14 C ages of the mixed water vary between 9 and 13 ka, i.e. Early Holocene–Late Pleistocene. Water 18 O and 2 H contents do not show a clear climatic signature. The Amurga volcanic Massif is on the southeast of the island of Gran Canaria. Brackish groundwater is found in the thick phonolite rock sequence. The unsaturated zone can be up to 200 m thick. Groundwater salinity is due to recharge under arid conditions and the influence of marine airborne salts. Groundwater 14 C age is possibly c . 11 ka, indicating a Late Pleistocene age water mixture. The small recharge due to aridity and the thick unsaturated zone explains this. Stable-water isotopes show no clear climatic signature.

Abstract A combined hydrogeological, geochemical and isotopic investigation was performed in the Aveiro Cretaceous coastal aquifer in order to investigate the rock-water interaction and the evolution of palaeowaters. The results indicate an aquifer with well-defined freshwater (<50 mg l −1 Cl − ) throughout most of the aquifer as far as the coastline and with very slow chemical kinetics for the water–rock interactions. The low mineralization may be explained by the mainly siliciclastic composition of the aquifer sediments, while calcite dissolution and cation exchange were also considered to be involved in the groundwater chemical evolution. This interpretation is in agreement with lithology and facies changes, and was validated by the PHREEQC-2 modelling results. Radiocarbon ages indicate a smooth gradient across the aquifer, implying continuous flow during the late Pleistocene and Holocene. Noble gas ratios indicate that the mean annual air temperatures were lower by 5–6°C at the last glacial maximum (LGM). In contrast to most areas with continental palaeowaters, the environmental isotopes indicate enrichment (0.8–1.0‰ in 18 O), interpreted as reflecting the composition of the oceans at the time of the LGM at this maritime site, as well as the constancy of the air mass circulations over the period to the present day. An outlet for the aquifer is inferred offshore to account for the observed geochemical data, with the possibility that freshwater could still also be found offshore.

Abstract Isotopic and noble gas data from a confined gravel aquifer in the Swiss Plateau has been investigated. From glaciomorphological studies it is well known that the Glatt Valley was repeatedly ice covered during the last glacial period. Corrected radiocarbon ages range from 0 to > 28 ka bp and reveal a gap of between 25 and 17 ka Be, indicating an interruption of groundwater recharge during the last glacial maximum. Based on 39 Ar measurements, a contribution of younger water components with residence times of a few hundred years have been identified in some waters. Recharge temperatures, estimated by analysis of noble gas contents, suggest a temperature difference of c . 5°C at the Holocene–Pleistocene transition at 12 ka bp . The long-term temporal 5180-recharge temperature relation over the last 30 ka has a slope of c . 0.49‰ °C −1 , consistent with the modern seasonal relation.

Abstract A review is given of palaeoclimatic and palaeoenvironmental evidence across Europe for the Weichselian period relevant to interpreting the emplacement and circulation of groundwaters. In addition, this provides the background against which the evidence of past climates and environments contained in groundwaters in coastal areas of Europe, from the Baltic to the Atlantic Ocean may be compared. For much of the Weichselian, although significantly colder than at present, conditions were favourable for the recharge of groundwater, as shown, for example, by periods of speleothem growth. During the last glacial maximum (LGM) recharge is likely to have ceased over much of permafrost-covered Europe, although shallow groundwater recharge from meltwater (generated by the geothermal gradients) could have taken place beneath the ice where pressure relief through tunnel valleys may have occurred. Modem recharge could have started as early as 13 14 C ka bp , but probably interrupted by the Younger Dryas between 11 and 10 14 C ka bp . In the Baltic areas, ice-dammed lakes inhibited the start of the modem hydrogeological regimes until c . 10.3 14 C ka bp . Tundra conditions prevailed over most of ice-free southern Europe at the time of the LGM. At this time the area south of the Portuguese–Spanish border retained a generally warm and relatively humid climate due to the maintenance of warmer sea-surface temperatures derived from Atlantic Ocean circulation. For most of coastal Europe, however, the most significant impact on groundwater circulation is likely to have been the lowering of sea levels that drained large areas of the shelf, such as the North Sea and the English Channel, and also had a significant impact on the Atlantic coast of the Iberian Peninsula where the maximum lowering of up to 130 m would have been experienced. This, together with the general changes in climate, would also have reorganized the atmospheric chemistry over sites in Europe that is likely to be recorded in the groundwater’s chemical and isotopic signatures.

Abstract Isotope and geochemical techniques are the primary way in which the residence time, recharge conditions and subsequent evolution of palaeowaters can be determined. Isotopic species and noble gas concentrations are used as residence time and palaeoclimate indicators. Among the former, 14 C is pre-eminent in late Quaternary studies because of an age range which covers the Pleistocene–Holocene transition. However, its use is constrained by frequent difficulties in determining the dilution of dissolved 14 C due to water–rock interaction. A combination of 14 C data with 226 Ra and 4 He results may be useful for Holocene waters but they can also be used to validate the carbon systematics assumed for 14 C dating. For waters beyond the range of 14 C dating, 81 Kr, 36 Cl, 4 He and chemical tracers can be applied. Stable isotope ratios and noble gas concentrations primarily reflect climatic conditions at the time of recharge. While the noble gases provide absolute values for recharge temperatures, stable isotopes are only relative indicators that vary regionally. The PALAEAUX programme has examined these aspects in some detail by looking at the δ 18 O shift between Pleistocene and Holocene waters on the European scale, and by calculating δ 18 O/Δ T ratios from δ 18 O v. recharge temperature plots for aquifers at different distances from the Atlantic Ocean. Indications are that the more positive δ 18 O value of ocean water during the Pleistocene dominates in the more westerly European countries over the negative δ 18 O shift during cooler conditions. There are also indications that air-mass circulation during the Pleistocene was similar to the present day. The evolution of a palaeowater can best be studied by measuring chemical tracers; this is possible in freshwater aquifers, where a clear trend of geochemical reactions is observed, and in freshening marine aquifers. Chemical and isotopic tracers can also be used to study the movement of the front between palaeowater and younger components that must be identified in coastal aquifers to guarantee a sustainable water use.

Abstract The response of coastal aquifer systems to global sea-level rise, the presence of permafrost and glaciation has been analysed using analytical and numerical models. The hydraulic connectivity between confined coastal aquifers and the sea largely controls their response to global sea-level rise. Open aquifer systems have direct hydraulic contact with the sea where they sub crop along the continental slope and base-level history for the aquifer is defined by sea-level history. In these systems, hydraulic heads equilibrate quickly to sea-level change at rates controlled by the aquifer hydraulic diffusivity. Interface movement lags behind the equilibration of the hydraulic heads and is controlled largely by the rate at which freshwater can be flushed from the aquifer through overlying semi-confining units. Interface movement occurs over time periods of tens of thousands of years. In contrast, closed aquifer systems lack direct hydraulic connectivity with the sea, which is controlled by the thickness and permeability of overlying semi-confining layers. During the Late Pleistocene–Early Holocene the base-level history for closed aquifer systems underlying the North Sea Basin was defined by the location of rivers and lakes in areas that are now offshore. These aquifers became coastal aquifers during the Holocene when rivers and lakes were inundated by rising sea levels. Salinization of closed aquifer systems may occur due to the downward diffusion of salts through overlying semiconfining layers in the presence of upward freshwater seepage. Aquifers overridden by glaciers respond in a manner that is largely controlled by aquifer transmissivity and geometry. The presence of permafrost inhibits recharge resulting in lower hydraulic heads and a reduction in aquifer fluxes.

Abstract Hydrogeochemical modelling was used to interpret water-sample analyses of three European aquifers: the East Midlands Triassic Sandstone (UK), the Tertiary Ledo-Paniselian (Belgium) and the Aveiro Cretaceous aquifer (Portugal). Soil CO 2 pressures at recharge, derived from inverse chemical modelling, correlate well with δ 18 O of the water. Higher soil CO 2 pressures correspond to less negative δ 18 O of the recharge water, indicating higher recharge temperatures. This trend is confirmed by noble gas temperatures from the East Midlands aquifer. Cation exchange and carbonate reactions were the most important chemical processes that contributed to the groundwater composition of all three aquifers. Transport modelling of the water quality of the Ledo-Paniselian aquifer confirmed the importance of cation exchange and elucidated that recharge of this aquifer occurs through preferential pathways.

Abstract Geophysical logging is shown to be a useful technique to support investigations of coastal aquifer hydrogeology. Formation logging can identify the geological layering and fluid logging can characterize the salinity distribution. The measurements also reveal wellbore flow to be common in coastal boreholes, which can mask the salinity stratification in the aquifer matrix. Geophysical logging can be used to guide water sampling and to provide information on the palaeohydrogeology. In combination with water sampling and age determinations, it has shown modern groundwaters overlying Holocene age groundwaters, in turn overlying groundwaters of Pleistocene age, within 150 m of the surface in some of the aquifers studied. Sea-level change in response to Pleistocene glaciations and deglaciations is recognized as a major control on the salinity of groundwaters and on the development of permeable flow routes in coastal aquifers. The permeable routes that developed by groundwater circulation to older and deeper base levels are now partly or wholly occupied by groundwaters of modern flow systems, and can be the focus for saline intrusion. The effects of Pleistocene sea-level change on aquifer development appear to be worldwide and are being increasingly recognized. Examples are described to illustrate the development of flow horizons in relation to rock layering, structure and base levels.

Abstract Modem groundwater that has recharged aquifers within the past 50 a shows the influence of humans globally, either by the presence of small concentrations of environmental tracers or in some cases by severe pollution. This study describes important environmental tracers (e.g. 3 H, 85 Kr, chlorofluorocarbons, SF 6 ) and contaminants (e.g. NO 3 − , pesticides, chlorinated solvents) for modem groundwater dating and recognition of human impacts. Some applications of the described tracers in aquifers investigated in the PALAEAUX study are presented in order to illustrate the advance of modem waters in European aquifer systems. The study shows that the location of the modern water interface varies within a range of between c . 10 and c . 100 m in the investigated aquifers due to variations in hydrogeological setting, climate and exploitation of the groundwater resource. The subsurface distribution of the modem water indicators and contaminants demonstrate that the advance of modem groundwaters and the fate of harmful substances in them have important implications for protection and development of the water resources. Contaminants that do not degrade or degrade only very slowly will advance further into the aquifers and may eventually contaminate even deep groundwater systems.

Abstract An overview is given of the status and origin of fresh and saline groundwaters in the sedimentary aquifers at or near the present European coastline. Results are presented as six regional maps summarizing, as far as possible, the conditions likely to have existed at the end of the Pleistocene, after the impact of glaciation, when groundwaters might be expected to have reached their maximum offshore evolution prior to the encroachment of sea water during the Holocene marine transgression. In the eastern Baltic, the groundwater evolution was different to other European regions in that freshwater heads were higher than the present day, promoting recharge during much of the Late Pleistocene. Near the North Sea coasts, there is generally evidence of freshwater movement to depths of 100–150 m but the absence of deeper freshwater (palaeowater) storage may relate to the low hydraulic gradients in the North Sea Basin. In the southeastern part of the North Sea brackish palaeowater is found between Tertiary marine sediments c . 300 m below the island of Rømø, 10 km off the Danish west coast. Freshwater of Pleistocene and Holocene ages is found in aquifers at the English Channel coast in several areas, to depths in excess of −300 m; offshore flow in the Late Pleistocene took place towards the central palaeovalley and some of this groundwater may be preserved off the present coastline. In the two Atlantic coastal areas of France and Portugal–Spain a contrast exists due to the proximity of the continental margin and different hydraulic gradients. In Portugal, freshwaters are found at the coastline, and probably offshore, that contain evidence of recharge during the lowered sea levels. In most of the southwestern Atlantic coast of Spain, fresh recent groundwater discharges along and beyond the coastline, while in the old estuary of the Guadalquivir River, saline Holocene water still encroaches the sediments. On the Mediterranean coast of France and Spain some salinity encroachment took place during sea-level rise. In most of the Spanish aquifers fresh recent groundwater has substituted for palaeowater, except for the low-lying areas (Ebro Delta, Inca-Sa Pobla Plain) where brackish Holocene water is still present.

Abstract Coastal regions of Europe have special water supply problems due to the population pressure, competing demands and the ever-present risk of saline intrusion from modern and old sea water. This is especially the case in southern Europe where touristic demands exacerbate water supplies, often in semi-arid regions. Palaeowaters emplaced at times of lowered sea level offer potential high-quality, high-value reserves in many areas, although a lack of understanding of the nature of the resource, together with exploitation for non-drinking purposes and indiscriminate drilling, may already have damaged the underground reservoirs and the reserves within them. These aquifers may, however, offer sites that are attractive for seasonal water storage. Palaeowaters generally are of high quality and are demonstrably free of human impacts. Good drilling practice and operation are required to avoid contamination, the mixing of palaeowaters with more saline waters and avoidance of marine intrusion. Two case studies illustrating the management practice in areas containing palaeowaters – in the French Mediterranean coast and the Llobregat Delta area of Catalonia, Spain – are given. These demonstrate, above all, the need for integrated development, observation and planning, which involves all the stakeholders, especially the beneficiaries and end-users. There is a need for improved regulation for the protection, use and management of aquifers containing palaeowaters at both the national and European scale, to consider the intrinsic value of uncontaminated palaeowaters as a unique, non-renewable source of drinking water. The value of such aquifers for subsequent freshwater storage and also for use as a brackish water source for desalination may also be considered.

Abstract Palaeowaters in Coastal Europe contains 17 contributions from an international array of authors. They discuss the history of groundwater evolution during the late Pleistocene in the coastal areas of Europe from the Baltic region to the Iberian peninsula and the Canary Islands. Geochemical and geophysical techniques for evaluating palaeowaters are reviewed. The focus of the book is on changes in the hydrogeological regime during the Quaternary and their impacts on groundwater movement and chemistry in European coastal aquifers. The work summarized in the papers was carried out by a partnership of European scientists under the auspices of the PALAEAUX project, an EC initiative. Researchers from the fields of hydrogeology, geochemistry, isotope hydrology and Quaternary studies attempted to reconstruct the most probable movement of groundwater in the study area over the past 100 000 years and its response to climatic events of global significance during the last glacial cycle. The results of this work, summarized in this volume, allow a better understanding of the water resources found at and near the coastlines of northern and western Europe. During times of lowered sea level, it appears that groundwaters were replenished to depths greater than occur at the present day. These pristine freshwater reserves are an irreplaceable asset. Their location at coastlines where populations and water demands are high and often seasonal means that they need careful management to avoid over-exploitation or contamination. The inevitable conflicts that this resource management creates are discussed. Palaeowaters in Coastal Europe: evolution of groundwater since the late Pleistocene will be of interest to Quarternary scientists, hydrogeologists, marine scientists engaged in coastal research and those involved in environmental science and the management of groundwater assests.