Groundwater Pollution in Spain: General Aspects

In spite of many aquifers still being in good condition, groundwater pollution is becoming a serious problem in some areas of continental and insular Spain, although it is not always recognized. Irrigated agriculture is an important source of pollutants, but industrial, mining and urban-related problems also exist. These go in parallel with serious salinity problems of diverse origin. The degree of knowledge with regard to these problems is still poor, and in many instances low priority is given to studies, prevention, control and remedial action. Water quantity aspects still receive most of the attention and economic resources. A new Water Act includes provisions for dealing with groundwater quality and pollution; they seem adequate to cope with existing problems, but their effectiveness, feasibility and willingness to be applied is still uncertain. The success not only depends on scientific and technical issues, but mainly in achieving an administration and management structure capable of coping with real problems and able to obtain the trust and cooperation of water users.     

Assessment and forecasting of the subsurface drain of the Aral Sea,Central Asia

Mathematical simulation techniques have been used to study the subsurface water-lake system. The volume of the subsurface drain from the Syrdarya artesian basin (Kazakhstan) into the Aral Sea depression was computed subject to the geoinformation-mathematical model of its hydrogeological conditions. Since the surface and subsurface (underground) water are interconnected, their movement has been measured during the undisturbed period (1960), the epignostic (1961–2014) period, and for forecasting problems for 2044 under two water withdrawal options. The first forecast option assumes the same withdrawal volume of subsurface water level which existed at the end of 2014. The second forecast option envisages the model assignment (from the start of 2015) of the water withdrawal in the production volumes of the subsurface water approved by the National Reserves Committee of the Republic of Kazakhstan. The simulation results showed that the technogenic factors in the explored area have a significant impact on the movement of the subsurface and surface water. Reduction of the Syrdarya and Amudarya rivers flows, production of subsurface water with multiple water-intake and unowned self-flowing wellbores promoted the desiccation of the Aral Sea. The proposed mathematical simulation technique used to assess the subsurface drain proved its efficiency and can be used for surveying the similar subsurface water-lake systems.     

The boron-organic carbon correlation in water

A linear correlation between boron and organic carbon has been identified for groundwater and surface water. The boron to organic carbon ratio is found to be higher for groundwaters than for surface waters, since surface waters are more heavily loaded with natural organic matter. This correlation in water might result from the complexation of boron with polar organic compounds, not adsorbed on activated carbon, or from independent species. Any deviation from the boron/organic carbon ratio is used to identify pollution events for both boron or organic compounds, and to characterise the origin of unusual water chemistries. Moreover, such a correlation could be used to define natural water pristine conditions in order to restore good quality of water resources.     

Quantitative assessment of intrinsic groundwater vulnerability to contamination using numerical simulations

Intrinsic vulnerability assessment to groundwater contamination is part of groundwater management in many areas of the world. However, popular assessment methods estimate vulnerability only qualitatively. To enhance vulnerability assessment, an approach for quantitative vulnerability assessment using numerical simulation of water flow and solute transport with transient boundary conditions and new vulnerability indicators are presented in this work. Based on a conceptual model of the unsaturated underground with distinct hydrogeological layers and site specific hydrological characteristics the numerical simulations of water flow and solute transport are applied on each hydrogeological layer with standardized conditions separately. Analysis of the simulation results reveals functional relationships between layer thickness, groundwater recharge and transit time. Based on the first, second and third quartiles of solute mass breakthrough at the lower boundary of the unsaturated zone, and the solute dilution, four vulnerability indicators are extracted. The indicator transit time t₅₀ is the time were 50% of solute mass breakthrough passes the groundwater table. Dilution is referred as maximum solute concentration C_max in the percolation water when entering the groundwater table in relation to the injected mass or solute concentration C₀ at the ground surface. Duration of solute breakthrough is defined as the time period between 25% and 75% (t_25%-t_75%) of total solute mass breakthrough at the groundwater table. The temporal shape of the breakthrough curve is expressed with the quotient (t_25%-t_50%) / (t_25%-t_75%). Results from an application of this new quantitative vulnerability assessment approach, its advantages and disadvantages, and potential benefits for future groundwater management strategies are discussed.     

A hydrogeological study of the Sembawang hot spring in Singapore

A hydrogeological study of a natural hot spring at Sembawang, Singapore, has been undertaken, including boreholes of up to 100 m in depth, pumping tests, water chemistry analyses and temperature monitoring. The paper describes the investigations undertaken at the site, presents the data obtained and discusses a postulated hydrogeological and hydrothermal system of which the hot spring is a part. Electronic Publication     

Complex hydrological controls on wet dune slacks: the importance of local variability

Dune slacks are a species-rich habitat controlled largely by water chemistry and fluctuations in groundwater. Changes in water chemistry and water table level were analysed in 8 piezometers and 15 ephemeral surface water locations at a large UK dune system over a 12-month period. Total nitrogen concentrations in groundwater varied from 0.27-8.21 mg N L(-1), where dissolved organic nitrogen was dominant at the low nitrogen locations and nitrate was dominant at the high nitrogen locations. Principal components analysis of the water chemistry suggests at least four chemically distinct groundwater signatures. Water levels showed strong temporal heterogeneity. Comparisons of water levels with antecedent rainfall identified a component of year-round groundwater feed and differing seasonal responses overlain by a complex series of lags. In summer, there were lags of four, six and seven months with an additional rapid peaky response to daily rainfall with a one-day lag. In winter, water levels were strongly influenced by exogenous groundwater supply, but again exhibited multiple lags. This study shows that local variations in water chemistry and in hydrological regime can be more complicated than previously thought, with clear implications for optimum management of these high priority habitats for conservation.     

城市给水工程规划前瞻性、灵活性、可操作性的实践——以龙岩市中心城区给水专项规划为例

龙岩中心城区是全省唯一一个现状以地下水作为城市供水主要水源的城市,较之其它城市,规划中涉及更多的问题要予以解决。龙岩市中心城区给水专项规划对出现的一系列问题进行了深入地分析研究,均针对性提出了有效的解决方案,并成功的将＂高速公路模式＂主干管设计理念应用到此次工程规划实例中,使规划具有很强的应变能力,更具前瞻性、灵活性与...     

The progressive salination of groundwater in Beirut,Lebanon

The degradation in groundwater quality in Greater Beirut, the subject of several investigations in the past two decades, is attributable to seawater infiltration into the coastal aquifer induced by the excessive and uncontrolled groundwater utilization. The present study elucidates the increasing trend in seawater infiltration from 1971 to 1985. The brackish groundwater, generally used domestically for washing and flushing, is now creating extensive corrosion and scale‐formation problems that have to be faced by the users. At this critical stage, effective measures must be instituted that include the provision of adequate public water supplies to facilitate the control of groundwater utilization.     

Water policy,climate change and adaptation in South Asia

Scarcity will affect nearly two-thirds of the world in the near future. The impacts of climate change are likely to exacerbate these problems and unless appropriate adaptation strategies are adopted, resilience is difficult to achieve. The paper surveys the water resources available in South Asian countries and takes into account the projected climate change impacts on these resources. The paper also analyses the water policies and formulates a conceptual water policy framework in which adaptation is central.     

Innovative water rates as a policy tool for drought response: Two case studies from Utah,USA

Drought in the Western U.S. has elevated the need for innovative water pricing. We describe two utilities whose novel pricing structures reflect water availability and reasonable use expectations. One has a physical basis of water rights, landscape water needs, and irrigated area; the other has a hydrologic basis of an annual water supply forecast. Both utilities charge users tiered (increasing block) rates for an adjustable water allotment. The rates have proved hydrologically beneficial, socially equitable, and financially sustainable during the drought, suggesting that water pricing can be an effective policy tool for responsive water management.     

A sustainable framework for water resources management in an urban watershed: the case of Volos,Greece

The implementation of sustainable development principles in water resources management refers to an integrated management and coordination of the entirety of the actions and interventions that concern the water ecosystem, or parts of it, within a watershed. This procedure is accomplished through the development and application of an overall management plan at a hydrological basin level. This concept was followed by the water resources management plan of the city of Volos' watershed, which is presented in this paper. The main objective is the choice of the best set, among others, of hydraulic projects, which will be able to re-establish the balance in the basin's deficient water budget, satisfying at the same time future urban water demand. Decision making was carried out using a GIS tool and involved traditional water capture hydraulic projects on the one hand and sustainable water saving measures on the other. The whole procedure is being developed in an area with serious environmental problems, concerning mainly the groundwater resources. The particularity here is that the alternative solutions strongly depend on administrative agreement and consensus between relevant authorities.     

Competition in Urban Water and Sewage: The Case of Sydney,Australia

Policy makers have long grappled with the problems associated with introducing competition into natural monopoly industries such as railways, telecommunications, electricity and gas in order to eliminate excess profits and assure efficient provision of services. In the case of water supply and wastewater disposal in urban centres this process has tended to be even more difficult. This article analyses the circumstances surrounding the granting of third party access to infrastructure facilities in the water and wastewater industry in Australia's largest city, Sydney, and identifies difficulties that have been involved in this process. The effective introduction of competition into the water and wastewater industries, through robust access arrangements, would provide an additional path for the diversification of water sources, and potentially in ways that minimise environmental impacts.     

Hydrogeochemistry along the flow path of a confined aquifer,Düzce plain,north western Turkey

The Düzce plain is formed of Quaternary deposits derived from the surrounding hills, which feed water to three aquifers. The groundwater flow direction in the first confined aquifer is towards Efteni Lake and the Büyük Melen River. Generally the waters have a low concentration of minerals adjacent to the hills from which they are recharged while the groundwater increases in mineral content as it passes through the confined aquifer. Although Ca²⁺, HCO₃ ⁻, total hardness, TDS-EC and Na⁺ values increase along the groundwater flow path, they remain within the limits specified by standards related to drinkability and industrial/agricultural usages.      

Servant of too many masters: Residential water pricing and the challenge of sustainability

This paper discusses the state-of-the-art of the economic debate around water pricing, focussing on residential water supply and sanitation. Water pricing lays at the crossroads of many fields of economic analysis, and may be used to address many different problems: efficient allocation of water resources, ecological sustainability, guarantee of social rights, financial viability of investments. Different problems require different approaches and solutions. Rather than a “magic stick” that solves all problems by simply “getting the price right”, water charges must be seen as one of the many levers that policymakers can use: possibly a very effective one, but keeping in mind that it cannot solve all problems at the same time. Diversely from a simplistic interpretation of mainstream economics, deeply rooted in the European water policy, full-cost recovery and economic efficiency, social and ecological sustainability are separate issues that must not be confounded. This statement leads the way to a wider and more creative use of public finance.     

Hydrogeological studies on the Tarkwa gold mining district,Ghana

The physical hydrogeology of the Tarkwa area has been evaluated with a view to improving the understanding of its groundwater characteristics. It has been inferred that aquifers in the Tarkwa area possess dual and variable porosity and heterogeneous permeability with predominantly limited storage properties. Both soil infiltration and pumping tests have shown that the Banket Series has the best hydraulic features, but the Banket rocks are host rocks for gold. The effect of mining on the groundwater regime is discussed, comparing groundwater recharge estimates obtained using the water balance method (299±72 mm year⁻¹) and the stream hydrograph method (192±30 mm year⁻¹).      

Modelling the long-term changes in stream, soil and ground water chemistry for an acid moorland in the Welsh uplands: the influence of variations in chemical weathering

A long-term model of stream acidification, MAGIC, has been applied to an acidic moorland catchment, the Gwy, in mid-Wales. This application has been used to examine the effects of variability of weathering on soil, groundwater and stream water chemistry from 1844 to the present day and onwards to 2080 with a predicted acidic oxide reduction of 60% in the future. The results show that weathering initially affects soil, groundwater and stream water chemistry profoundly. Despite this, the results indicate that a simple two-layer (one soil and one groundwater end-member) model can still provide a good prediction of long-term stream water quality even when each soil and groundwater area is heterogeneous in composition. The work provides support for the use of the lumped MAGIC model. However, for the predictions to be applicable it is shown that it is critical that the relative contribution of waters and soil exchange materials from the hydrochemically distinct regions within the catchment are adequately represented within the model. This probably means that further field work is required to examine source area contributions.     

Water safety plans for piped urban supplies in developing countries: a case study from Kampala,Uganda

Full cost recovery is a major and complex issue that has gained high recognition in recent years. The Water Framework Directive promotes the idea that water charging should act as an incentive for the sustainable use of water resources. Thus, all Member States should take into consideration the principle of recovery of the total cost of water services, which includes environmental and resource costs as well. In order to evaluate various aspects of current water policy, to investigate the perspectives of water saving, to explore new approaches toward sustainable water management in the water supply sector and to evaluate water price elasticity, a survey has been performed recently in the city of Volos, concerning the residential sector. The influence of some selected variables is examined, residential water demand curve and water price elasticity are calculated. Estimations of future water demand under different pricing policies are also performed. Finally, the full water cost for the city of Volos is estimated and essential conclusions concerning water pricing and public participation are drawn.     

The contribution of human activities to subsurface environment degradation in Greater Jakarta Area, Indonesia

This study examines the factors of human activities causing environmental stresses on the subsurface environments in the urban settings of Jakarta. A major objective of this study is to identify the basin geometry and estimate how critical is the degradation of the subsurface environment within the basin, and it covered micro-palaeontology and chemical analyses, the decrease of water level, and GPS data. New data on shallow groundwater quality is provided and the results indicate strong evidence for human activities have influenced the degradation of the Jakarta subsurface environment.     

A review of residential water conservation tool performance and influences on implementation effectiveness

Water scarcity and household water consumption has received increasing attention on national public agendas in recent years. At the same time a number of important demand-side management (DSM) studies have been reported on by non-academic institutions, and there is a need for a comprehensive, up to date review of the impacts of DSM tools and the factors which influence their effectiveness. This paper aims to address an apparent lack of coverage in the academic literature by presenting a review of residential DSM tools using reports of recent DSM campaigns in the western (developed) world. The central objectives are to understand the potential for residential DSM tools to save water in different types of household under varying conditions and to identify influences on implementation effectiveness. In the discussion, we explore causes of uncertainty in DSM planning including the non-transferability of trends and existing methods of evaluation, and describe some of the resulting problems. The conclusions offer recommendations as to areas that require, and offer the greatest scope, for future research. This review article will be of interest to, among others, water company professionals, policy makers, regulators, researchers, and environmental agencies.     

Erratum to “Effects of intensive urbanization on the intrusion of shallow groundwater into deep groundwater: Examples from Bangkok and Jakarta”

Asian megacities have severe pollution problems in both coastal and urban areas. In addition, the groundwater potential has decreased and land subsidence has occurred because of intensive groundwater pumping in urban areas. To prevent the adverse effects of urbanization on groundwater quality, it is necessary to confirm the changes in groundwater flow and contaminant transport caused by urbanization. We examined the effects of urbanization on contaminant transport in groundwater. The research areas were located around Bangkok, Thailand, and akarta, Indonesia, cities with populations of approximately 8 and 12 million, respectively. Each metropolitan city is located on a river delta and is adjacent to a bay. We measured the water level and collected water samples at boreholes at multiple depths (100 to 200 m) in 2004 and 2006 in Bangkok and Jakarta, respectively. The current hydraulic potential is below sea level in both cities because of prior excess abstraction of groundwater. As a result, the direction of groundwater flow is now downward in the coastal area. The Cl⁻ concentration and δ¹⁸O distributions in groundwater suggest that the decline in hydraulic potential has caused the intrusion of seawater and shallow groundwater into deep groundwater. Concentrations of Mn and NO3⁻-N in groundwater suggest the intrusion of these contaminants from shallow to deep aquifers with downward groundwater flow and implies an accumulation of contaminants in deep aquifers. Therefore, it is important to recognize the possibility of future contaminant transport with the discharge of deep groundwater into the sea after the recovery of groundwater potential in the coastal areas.