Sustainable Pumping Research Articles

Assessing the impacts of climate change on sustainable management of coastal aquifers

Water is a vital resource for the survival of not only human population, but also almost all ecosystems. Constituting 30 % of all freshwater, groundwater is the main source of available freshwater. Coastal aquifers, which serve as the major freshwater source for densely populated zones, are of vital importance and quite vulnerable to climate change. This paper examines the significant consequences of climate change, decreasing recharge rates, sea-level rise and increasing freshwater demand on the sustainable management of coastal aquifers, via a hypothetical case study. A 3-D numerical model is developed using SEAWAT, to simulate a circular island aquifer in the form of a freshwater lens surrounded by saltwater. Issues such as sloping land surface resulting in landward migration of the coastal boundary and transient response of the system due to pumping are considered through a set of predictive simulations. To assess the sensitivity of the model results to important parameters, a sensitivity analysis is performed. Results of this research, revealing the effects of mentioned pressures on the long-term sustainability of the freshwater resource, are evaluated on the basis of groundwater reserves and intrusion of the freshwater–saltwater interface in lateral and vertical directions. These outcomes are further used to determine the sustainable pumping rate of the system, considering both quantity and quality of the groundwater resources.

Chemical Characteristics of Surface Water and Groundwater in Coastal Watershed, Mekong Delta, Vietnam

The objective of this research was to provide hydrological and stable isotopic information to figure out the characteristics of surface water and groundwater in Cu Lao Dung (CLD) Island, a coastal area in the Mekong Delta, South of Vietnam. Water samples were collected in March 2013 during the driest period of the year. The basic tracing elements of water showed that groundwater was characterized by fresh water of Ca-HCO3 type, whilst almost river and canal water samples were categorized in saline water of Na-Cl type. Groundwater is only fresh water source for drinking purpose in this area, because river and canal water cannot be used for that due to serious seawater intrusion. Moreover, the results of inorganic solute concentration and stable isotopic compositions suggest that currently, interaction between river/canal water and groundwater may not occur in CLD Island. This implies that main recharge areas of the groundwater seem to be located outside of the CLD Island. For sustainable groundwater pumping, an appropriate management is necessary in the coastal areas in the Mekong Delta; more investigation, not only in small areas but also in large scale of Mekong Delta, is needed.

On the Variables to be Considered in Assessing the Impact of Climate Change to Alluvial Aquifers: A Case Study in Central Italy

Most of the scientific community agrees that global climate change is occurring with a general increase in mean overall temperature (+0.74±0.18°C from 1906-2005) and that the precipitation pattern in Europe is trending toward wetter conditions in the northern region and drier conditions in the southern and central-eastern regions. A much larger uncertainty concerns how the changes in precipitations will impact on the water resources, particularly on the groundwater. The goal of this paper is to investigate the variables to be considered in order to estimate the Sustainable Pumping Rate of an aquifer (SPR) in a context of climate change. For this goal the case study of the Petrignano d’Assisi porous aquifer has been considered, mainly fed by the inflow from the carbonatic ridges and by the effective infiltration; it is exploited since the 1970s through a well field (about 350 l/s). Changes in the precipitation regime could significantly affect the recharge to the aquifer and the related SPR. This study shows the key role played by the interactions of the aquifer with the surface bodies (rivers): in case of a significant decreasing in the effective infiltration, the aquifer system decreases the outflow to the rivers (base flow) leaving almost constant the sustainable pumping rate.

Optimized Sustainable Groundwater Extraction Management: General Approach and Application to the City of Lucknow, India

In rapidly developing urban areas of emerging countries, increased water demand has led to enormous groundwater withdrawal, calling out for sustainable groundwater management. We suggest implementing a sustainable pumping rate concept based on numerical modeling of the managed aquifer. Sustainability is achieved by constraints regarding (1) a minimum groundwater discharge rate to gaining rivers (ecological constraint) and (2) a maximum drawdown along the city boundaries (social constraints) to prevent excessive groundwater depletion in the neighboring peri-urban and rural areas. The total groundwater extraction is maximized subject to these constraints, leading to specific extraction patterns throughout the city, depending upon the values set for the constraints. The optimization is performed by linear programming. For a given extraction rate, the two constraints can be traded off by the groundwater manager, causing different wells to be activated or deactivated. We demonstrate the applicability of the methodology by the example of the city of Lucknow, India, but it can be transferred to other cities facing conflicts of managing groundwater resources.

Dynamics of Nitric Oxide Activity are Sufficient and Optimal to Drive Lymphatic Pumping

The lymphatic system is critical for maintaining fluid homeostasis and immunosurveillance in tissues, but it malfunctions in many pathologies. Active pumping of fluid by collecting lymphatic vessels is a critical component of lymphatic function, transferring fluid from initial lymphatic beds, but the details of this mechanism are not well understood. Previous work has shown that lymphatic vessels are equipped with one‐way intraluminal valves to maintain unidirectional flow, and that the contraction of collecting lymphatic vessels is effected by nitric oxide (NO). Here we present a computational model that reproduces the relevant dynamics of lymphatic contraction based on known biological principles of nitric oxide combined with fluid dynamics. Shear stresses imparted by the flowing lymph induce nitric oxide locally, which cause a relaxation (dilation) of the vessel wall. The subsequent rapid degradation of NO allows for vessel contraction and fluid movement, which combined with intraluminal valves results in efficient and robust pumping.We hypothesized that cyclic changes in shear stress and the resulting nitric oxide levels are able to produce and sustain pumping in a lymphatic vessel. To test this, we simulated lymphatic pumping using a lattice Boltzmann (LB) approach. The vessel walls consist of moving boundaries affected by a force proportional to the NO concentration and a damped, harmonic restoring potential. The NO decay and diffusion are calculated by a finite difference scheme. Our simulations show that lymphatic pumping is a stable and robust process, able to operate over a range of parameter space. Contributing to this stability is the short lifetime of NO, optimized for efficient, sustained pumping. We also demonstrate how gravity influences the pumping and that no external steering mechanism is needed.

Stream Depletion from Pumping a Semiconfined Aquifer in a Two-Layer Leaky Aquifer System

We consider the case of pumping a semiconfined aquifer overlain by a phreatic aquifer hydraulically connected to an infinitely long and straight stream. The hydraulics of the system are described by a linearized model in which it is assumed that flow in the aquifers is essentially horizontal, and that drawdown in the phreatic aquifer is small enough to allow the water table to be sufficiently well described by the Theis equation. Fourier-Laplace transforms of drawdown are obtained and numerically inverted. Comparisons are made with another well-known analytic model of Hunt, who considered a single aquifer/aquitard system. It is observed that while both models may have excellent agreement during the initial phase of pumping, the longer-term consequences of sustained pumping are quite distinct.

Factors Governing Sustainable Groundwater Pumping near a River

The objective of this paper was to provide new insights into processes affecting riverbank filtration (RBF). We consider a system with an inflatable dam installed for enhancing water production from downstream collector wells. Using a numerical model, we investigate the impact of groundwater pumping and dam operation on the hydrodynamics in the aquifer and water production. We focus our study on two processes that potentially limit water production of an RBF system: the development of an unsaturated zone and riverbed clogging. We quantify river clogging by calibrating a time-dependent riverbed permeability function based on knowledge of pumping rate, river stage, and temperature. The dynamics of the estimated riverbed permeability reflects clogging and scouring mechanisms. Our results indicate that (1) riverbed permeability is the dominant factor affecting infiltration needed for sustainable RBF production; (2) dam operation can influence pumping efficiency and prevent the development of an unsaturated zone beneath the riverbed only under conditions of sufficient riverbed permeability; (3) slow river velocity, caused by dam raising during summer months, may lead to sedimentation and deposition of fine-grained material within the riverbed, which may clog the riverbed, limiting recharge to the collector wells and contributing to the development of an unsaturated zone beneath the riverbed; and (4) higher river flow velocities, caused by dam lowering during winter storms, scour the riverbed and thus increase its permeability. These insights can be used as the basis for developing sustainable water management of a RBF system.

Use of stream response functions to determine impacts of replacing surface-water use with groundwater withdrawals

A regional-scale numerical groundwater model is used to study the impacts of replacing surface-water use with groundwater wells to improve low-flow stream conditions for endangered species within the Bertrand and Fishtrap watersheds, southern British Columbia, Canada and Washington, USA. Stream response functions ranging from 0 to 1.0 were calculated for individual wells placed within a steady-state groundwater flow model at varying distances from the streams to determine the impact that these replacement wells, operating under sustained pumping rates, would have on summer instream flows. Lower response ratios indicate groundwater pumping will have less of an impact on streamflow than taking an equivalent amount of water directly from a surface-water source. Results show that replacing surface-water use with groundwater withdrawals may be a viable alternative for increasing summer streamflows. Assuming combined response factors should be ≤0.5 for irrigators to undergo the expense of installing new wells, ~57% of the land area within 0.8 km of Bertrand Creek would be suitable for replacement wells. Similarly, 70% of the land area within 0.8 km of Fishtrap Creek was found to be appropriate. A visual analysis tool was developed using STELLA to allow stakeholders to quickly evaluate the impact associated with moving their water right.

The Sustainable Pumping Rate Concept: Lessons from a Case Study in Central Italy

The term sustainable pumping rate (SPR) is defined as the maximum pumping rate that can be maintained indefinitely without mining an aquifer, and is different from the concept of safe yield (SY), which takes into account also aspects related to the much wider concept of sustainability. The assessment of the SPR for the case study of Petrignano d'Assisi, an alluvial aquifer located in Central Italy, shows the need for a reliable estimate of the global water budget of the aquifer, particularly of the recharge under undisturbed conditions; however, the latter is not sufficient, because the SPR is affected also by the geometry of the aquifer, the hydraulic conductivity pattern, the variation of recharge/discharge ratio induced by the abstractions, and so on. All these aspects are analyzed by means of a numerical flow model calibrated both under undisturbed conditions (1974) and under exploitation conditions (1998 to 2004). The steady-state modeling results show that the relation between recharge and abstractions both at local and global scale is a key point in order to estimate a long-term SPR. Moreover, as it could be necessary to overexploit the aquifer for short periods, e.g., during drought episodes, the estimate of SPR must be performed also in transient conditions, in order to take into account the characteristic time of depletion and the successive recovery.

Geochemical detection of carbon dioxide in dilute aquifers

BackgroundCarbon storage in deep saline reservoirs has the potential to lower the amount of CO2 emitted to the atmosphere and to mitigate global warming. Leakage back to the atmosphere through abandoned wells and along faults would reduce the efficiency of carbon storage, possibly leading to health and ecological hazards at the ground surface, and possibly impacting water quality of near-surface dilute aquifers. We use static equilibrium and reactive transport simulations to test the hypothesis that perturbations in water chemistry associated with a CO2 gas leak into dilute groundwater are important measures for the potential release of CO2 to the atmosphere. Simulation parameters are constrained by groundwater chemistry, flow, and lithology from the High Plains aquifer. The High Plains aquifer is used to represent a typical sedimentary aquifer overlying a deep CO2 storage reservoir. Specifically, we address the relationships between CO2 flux, groundwater flow, detection time and distance. The CO2 flux ranges from 103 to 2 × 106 t/yr (0.63 to 1250 t/m2/yr) to assess chemical perturbations resulting from relatively small leaks that may compromise long-term storage, water quality, and surface ecology, and larger leaks characteristic of short-term well failure.ResultsFor the scenarios we studied, our simulations show pH and carbonate chemistry are good indicators for leakage of stored CO2 into an overlying aquifer because elevated CO2 yields a more acid pH than the ambient groundwater. CO2 leakage into a dilute groundwater creates a slightly acid plume that can be detected at some distance from the leak source due to groundwater flow and CO2 buoyancy. pH breakthrough curves demonstrate that CO2 leaks can be easily detected for CO2 flux ≥ 104 t/yr within a 15-month time period at a monitoring well screened within a permeable layer 500 m downstream from the vertical gas trace. At lower flux rates, the CO2 dissolves in the aqueous phase in the lower most permeable unit and does not reach the monitoring well. Sustained pumping in a developed aquifer mixes the CO2-affected water with the ambient water and enhances pH signal for small leaks (103 t/yr) and reduces pH signal for larger leaks (≥ 104t/yr).ConclusionThe ability to detect CO2 leakage from a storage reservoir to overlying dilute groundwater is dependent on CO2 solubility, leak flux, CO2 buoyancy, and groundwater flow. Our simulations show that the most likely places to detect CO2 are at the base of the confining layer near the water table where CO2 gas accumulates and is transported laterally in all directions, and downstream of the vertical gas trace where groundwater flow is great enough to transport dissolved CO2 laterally. Our simulations show that CO2 may not rise high enough in the aquifer to be detected because aqueous solubility and lateral groundwater transport within the lower aquifer unit exceeds gas pressure build-up and buoyancy needed to drive the CO2 gas upwards.

Transport and detection of carbon dioxide in dilute aquifers

Abstract Carbon storage in deep saline reservoirs has the potential to lower the amount of CO 2 emitted to the atmosphere and to mitigate global warming. Leakage back to the atmosphere through abandoned wells and along faults would reduce the efficiency of carbon storage, possibly leading to health and ecological hazards at the ground surface, and possibly impacting water quality of near-surface dilute aquifers. We use static equilibrium and reactive transport simulations to test the hypothesis that perturbations in water chemistry associated with a CO 2 gas leak into dilute groundwater are important measures for the potential release of CO 2 to the atmosphere. Simulation parameters are constrained by groundwater chemistry, flow, and lithology from the High Plains aquifer. The High Plains aquifer is used to represent a typical sedimentary aquifer overlying a deep CO 2 storage reservoir. Specifically, we address the relationships between CO 2 flux, groundwater flow, and detection time and distance. The CO 2 flux ranges from 103 to 2×106 t/yr to assess chemical perturbations resulting from relatively small leaks that may compromise long-term storage, water quality, and surface ecology, and larger leaks characteristic of short-term well failure. Reactive transport simulations show the CO 2 leakage into a dilute groundwater creates a slightly acid plume that can be detected at some distance from the leak source due to groundwater flow and CO 2 buoyancy. pH breakthrough curves demonstrate that CO 2 leaks can be easily detected for CO 2 flux 104 t/yr within a 15-month time period. Sustained pumping in a developed aquifer mixes the CO 2 -affected water with the ambient water and enhances pH signal for small leaks (103 t/yr) and reduces pH signal for larger leaks (104t/yr). Detection of CO 2 leaks in aquifers by changes in pH and carbonate chemistry is readily available and well understood. Leaks produce a measurable change in pH that is still within range of natural waters, even for high flux rates (2×106 t/yr). Reactive transport modeling is a critical component to the design and effective performance of measurement, monitoring, and verification plans for carbon storage.

Remediating Large Plumes: Overcoming the Scale Challenge

Introduction The remediation industry, now three decades old, continues to evolve. This is driven by many factors: technological developments, a need to address emerging contaminants, regulatory changes, economic factors, and sustainability considerations. These have created both challenges and opportunities at different stages of the industry’s evolution. Although many things have changed with time, one of the most difficult practical challenges remains—namely, how to deal with large dissolved plumes (referred to as “large plumes” throughout this article). Presumptive thinking emphasizes containment and management of these large plumes rather than focusing on mass removal and site closures. The term large plume obviously highlights scale as being the critically defining attribute; however, it is worth identifying other attributes that are discussed in this article:

Water troubles in a Pacific atoll town

South Tarawa is a town on an isolated Pacific atoll of approximately 46,000 people, with absolute water scarcity, poor water safety and consequently water-related problems. It relies on shallow groundwater, with contributions from rainwater tanks and desalination. Due to a combination of factors such as small scale, limited human resources, system complexity, isolation and lack of financial resources, water management capacity is inadequate. Sustainability of groundwater resources is also uncertain and there are indications that groundwater has been extracted above the sustainable pumping rates. Social complexity is highlighted by the resistance from traditional landowners to the attempts to deal with the supply-side deficit through establishment of new infiltration galleries. In this paper, issues relating to water management in South Tarawa are reviewed. This follows on to an exploration of possible strategies to improve the existing situation. This research forms an empirical building block in the foundation of a larger study, aiming at developing a framework for strategic and adaptive small town water management. In particular, the larger study explores the options and viability of co-management of water and land resources in small scale urban areas as an alternative to traditional urban management approaches.

Ground Water Sustainability: Methodology and Application to the North China Plain

This article analyzes part of a ground water flow system in the North China Plain (NCP) subject to severe overexploitation and rapid depletion. A transient ground water flow model was constructed and calibrated to quantify the changes in the flow system since the predevelopment 1950s. The flow model was then used in conjunction with an optimization code to determine optimal pumping schemes that improve ground water management practices. Finally, two management scenarios, namely, urbanization and the South-to-North Water Transfer Project, were evaluated for their potential impacts on the ground water resources in the study area. Although this study focuses on the NCP, it illustrates a general modeling framework for analyzing the sustainability, or the lack thereof, of ground water flow systems driven by similar hydrogeologic and economic conditions. The numerical simulation is capable of quantifying the various components of the overall flow budget and evaluating the impacts of different management scenarios. The optimization modeling allows the determination of the maximum "sustainable pumping" that satisfies a series of prescribed constraints. It can also be used to minimize the economic costs associated with ground water development and management. Furthermore, since the NCP is one of the most water scarce and economically active regions in the world, the conclusions and insights from this study are of general interest and international significance.

Pleistocene hydrology of North America: The role of ice sheets in reorganizing groundwater flow systems

While the geomorphic consequences of Pleistocene megafloods have been known for some time, it has been only in the past 2 decades that hydrogeologists and glaciologists alike have begun to appreciate the important impact that ice sheet–aquifer interactions have had in controlling subsurface flow patterns, recharge rates, and the distribution of fresh water in confined aquifer systems across North America. In this paper, we document the numerous lines of geochemical, isotopic, and geomechanical evidence of ice sheet hydrogeology across North America. We also review the mechanical, thermal, and hydrologic processes that control subsurface fluid migration beneath ice sheets. Finite element models of subsurface fluid flow, permafrost formation, and ice sheet loading are presented to investigate the coupled nature of transport processes during glaciation/deglaciation. These indicate that recharge rates as high as 10 times modern values occurred as the Laurentide Ice Sheet overran the margins of sedimentary basins. The effects of ice sheet loading and permafrost formation result in complex transient flow patterns within aquifers and confining units alike. Using geochemical and environmental isotopic data, we estimate that the volume of glacial meltwater emplaced at the margins of sedimentary basins overrun by the Laurentide Ice Sheet totals about 3.7 × 104 km3, which is about 0.2% of the volume of the Laurentide Ice Sheet. Subglacial infiltration estimates based on continental‐scale hydrologic models are even higher (5–10% of meltwater generated). These studies in sum call into question the widely held notion that groundwater flow patterns within confined aquifer systems are controlled primarily by the water table configuration during the Pleistocene. Rather, groundwater flow patterns were likely much more complex and transient in nature than has previously been thought. Because Pleistocene recharge rates are believed to be highly variable, these studies have profound implications for water resource managers charged with determining sustainable pumping rates from confined aquifers that host ice sheet meltwater.

Population Pharmacokinetics and Proton Pump Inhibitory Effects of Intravenous Lansoprazole in Healthy Japanese Males

A total of 56 healthy Japanese males were enrolled in single- or multiple- dose pharmacokinetic trials of intravenous lansoprazole administration. The population pharmacokinetics of the drug was evaluated using nonlinear mixed effects model (NONMEM) software. In addition, the effect of CYP2C19 polymorphism on proton pump inhibition by lansoprazole was investigated using 24-h intragastric pH monitoring in the 32 subjects. Time course of serum lansoprazole concentration following intravenous short infusion was well described by a 2-compartment model. The mean volume of the central and peripheral compartments was 0.110 and 0.201 l/kg, respectively. The mean inter-compartment clearance was estimated to be 0.0882 l/h/kg. The population mean value of systemic clearance in the homoEM (CYP2C19 1/ 1), heteroEM (CYP2C19 1/2 and 1/3), and PM (CYP2C19 2/2, 2/3, and 3/3) groups was 0.179, 0.109, and 0.038 l/h/kg, respectively. The mean intragastric pH following twice-daily doses of 30 mg lansoprazole was approximately 6, 5, and 4 in the PM, heteroEM, and homoEM groups, respectively. These findings indicate that large interindividual variability exists in the pharmacokinetics of intravenously administered lansoprazole, but that twice-daily infusion of a 30 mg dose leads to significant and sustained proton pump inhibition, even in the homoEM group, despite the short elimination half-life of the drug.

High-dose atorvastatin is associated with impaired myocardial angiogenesis in response to vascular endothelial growth factor in hypercholesterolemic swine

The disappointing results of myocardial angiogenic therapy have been attributed, in part, to endothelial dysfunction present in patients with coronary disease. Statins have established proendothelial properties but seem to have dose-dependent effects on angiogenesis. We investigated the functional and molecular effects of high-dose atorvastatin on vascular endothelial growth factor-induced myocardial angiogenesis in hypercholesterolemic swine. Yucatan miniswine (20-30 kg) were fed either a normal (ND group, n = 8) or high-cholesterol diet, with (HC-ATOR group, n = 8) or without (HC group, n = 8) atorvastatin (3 mg x kg(-1) x d(-1)), for 13 weeks. Chronic ischemia was induced by ameroid constrictor placement around the circumflex artery, followed 3 weeks later by perivascular vascular endothelial growth factor administration (2 microg over 4 weeks) with a sustained release osmotic pump. Microvessel relaxation responses, myocardial perfusion, and myocardial expression of angiogenic mediators were assessed 4 weeks later. Hypercholesterolemic swine demonstrated impaired microvessel relaxation to vascular endothelial growth factor (P < .01 vs ND group) and adenosine diphosphate (P < .001 vs ND group), which was normalized in the HC-ATOR group. After perivascular vascular endothelial growth factor administration, collateral-dependent myocardial perfusion was significantly increased in the ND group but decreased in both the HC and HC-ATOR groups (both P < .01 vs the ND group). The animals in the HC-ATOR group demonstrated increased myocardial expression of the antiangiogenic protein endostatin and increased Akt phosphorylation without significant changes in Akt and endothelial nitric oxide synthase expression. Atorvastatin treatment reverses hypercholesterolemia-induced endothelial dysfunction without appreciable improvements in collateral-dependent myocardial perfusion in response to vascular endothelial growth factor treatment. Increased myocardial endostatin expression and chronic Akt activation, associated with atorvastatin therapy, might account for the lack of improvement in the angiogenic response to vascular endothelial growth factor therapy.

Comment on “The persistence of the water budget myth and its relationship to sustainability” by J.F. Devlin and M. Sophocleous, Hydrogeology Journal (2005) 13:549–554

Devlin and Sophocleous (2005) have written a thoughtful and provocative article on the subject of sustainable pumping and sustainable groundwater-resources development. In the subject article, sustainable pumping was defined as “a pumping rate that can be maintained indefinitely without dewatering an aquifer”. Sustainable groundwater-resources development is, according to the subject article, a broader concept that encompasses groundwater use and its environmental and human repercussions. Devlin and Sophocleous (2005) contend that the definitions of sustainable pumping and sustainable groundwater-resources development have been confused by some in the groundwater community, and, that the confusion has led to the “water budget myth” (see also Bredehoeft 2002). The water budget myth is—according to Devlin and Sophocleous (2005)—the “idea that sustainable pumping must not exceed the recharge rate in a given aquifer”. A substantial portion of the subject article is devoted to proving that the water budget myth is conceptually flawed. This commentary presents an alternative interpretation of the relation between sustainable pumping and sustainable groundwater-resources development to that advocated by Devlin and Sophocleous (2005). This alternative interpretation renders superfluous the distinction between sustainable pumping and sustainable groundwater-resources and, as corollary, makes the water budget myth an innocuous—if not laudable—concept. In addition, this commentary argues that sustainable pumping, as defined in the subject article, has very limited practical applicability in the context of groundwater extraction under variable climate. This commentary argues that sustainable pumping must be adaptive and take into account climate fluctuations, especially protracted drought.

Groundwater modelling as a tool for the European Water Framework Directive (WFD) application: The Llobregat case

The European Water Framework Directive establishes the basis for Community action in the field of water policy. Water authorities in Catalonia, together with users are designing a management program to improve groundwater status and to assess the impact of infrastructures and city-planning activities on the aquifers and their associated natural systems. The objective is to describe the role of groundwater modelling in addressing the issues raised by the Water Framework Directive, and its application to the Llobregat Delta, Barcelona, Spain. In this case modelling was used to address Water Framework Directive in the following: (1) Characterisation of aquifers and the status of groundwater by integration of existing knowledge and new hydrogeological information. Inverse modelling allowed us to reach an accurate description of the paths and mechanisms for the evolution of seawater intrusion. (2) Quantification of groundwater budget (mass balance). This is especially relevant for those terms that are difficult to asses, such as recharge from river infiltration during floods, which we have found to be very important. (3) Evaluation of groundwater-related environmental needs in aquatic ecosystems. The model allows quantifying groundwater input under natural conditions, which can be used as a reference level for stressed conditions. (4) Evaluation of possible impacts of territory planning (Llobregat river course modification, new railway tunnels, airport and docks enlargement, etc.). (5) Definition of management areas. (6) The assessment of possible future scenarios combined with optimization processes to quantify sustainable pumping rates and design measures to control seawater intrusion. The resulting model has been coupled to a user-friendly interface to allow water managers to design and address corrective measures in an agile and effective way.

The persistence of the water budget myth and its relationship to sustainability

Sustainability and sustainable pumping are two different concepts that are often used interchangeably. The latter term refers to a pumping rate that can be maintained indefinitely without mining an aquifer, whereas the former term is broader and concerns such issues as ecology and water quality, among others, in addition to sustainable pumping. Another important difference between the two concepts is that recharge can be very important to consider when assessing sustainability, but is not necessary to estimate sustainable pumping rates. Confusion over this distinction is made worse by the Water Budget Myth, which comprises the mistaken yet persistent ideas that (1) sustainable pumping rates cannot exceed virgin recharge rates in aquifers, and (2) that virgin recharge rates must therefore be known to estimate sustainable pumping rates. Analysis of the water balance equation shows the special circumstances that must apply for the Water Budget Myth to be true. However, due to the effects recharge is likely to have on water quality, ecology, socioeconomic factors, and, under certain circumstances, its requirement for numerical modeling, it remains important in assessments of sustainability.