scholarly journals Assessment of groundwater resources: Nauru project 2010 – 2019

2019 ◽  
Author(s):  
Luca Alberti ◽  
Ivana La Licata ◽  
Louis Bouchet
Keyword(s):  
Climate Changes ◽  
Numerical Models ◽  
Groundwater Resources ◽  
Small Islands ◽  
Groundwater Extraction ◽  
Fresh Groundwater ◽  
Groundwater Exploitation ◽  
The Pacific ◽  
Freshwater Resource

Nauru is a small limestone island in the Pacific region where, as in many small islands in the world, the population heavilyrely upon groundwater as primary freshwater resource, in conjunction with rainwater and desalinated water.The Nauru project started in 2010 and led by Politecnico di Milano (http://nauru.como.polimi.it/), consisted on the hydrogeological characterization of the northern part of the island and the implementation of 3 numerical models for: (1) understanding the mechanisms governing groundwater flow and accumulation, (2) assess the adequate sustainable fresh groundwater exploitation in order to prevent saltwater upconing occurrences in the area more suitable for groundwater extraction and (3) to simulate future scenarios based on climate changes and population growth.

scholarly journals Impacts of Sea Level Rise and Groundwater Extraction Scenarios on Fresh Groundwater Resources in the Nile Delta Governorates, Egypt

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1690 ◽  
Author(s):  
Marmar Mabrouk ◽  
Andreja Jonoski ◽  
Gualbert H. P. Oude Essink ◽  
Stefan Uhlenbrook
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Driving Forces ◽  
Nile Delta ◽  
Saline Water ◽  
Groundwater Resources ◽  
Salt Transport ◽  
Groundwater Extraction ◽  
Fresh Groundwater ◽  
The Impact

As Egypt’s population increases, the demand for fresh groundwater extraction will intensify. Consequently, the groundwater quality will deteriorate, including an increase in salinization. On the other hand, salinization caused by saltwater intrusion in the coastal Nile Delta Aquifer (NDA) is also threatening the groundwater resources. The aim of this article is to assess the situation in 2010 (since this is when most data is sufficiently available) regarding the available fresh groundwater resources and to evaluate future salinization in the NDA using a 3D variable-density groundwater flow model coupled with salt transport that was developed with SEAWAT. This is achieved by examining six future scenarios that combine two driving forces: increased extraction and sea level rise (SLR). Given the prognosis of the intergovernmental panel on climate change (IPCC), the scenarios are used to assess the impact of groundwater extraction versus SLR on the seawater intrusion in the Delta and evaluate their contributions to increased groundwater salinization. The results show that groundwater extraction has a greater impact on salinization of the NDA than SLR, while the two factors combined cause the largest reduction of available fresh groundwater resources. The significant findings of this research are the determination of the groundwater volumes of fresh water, brackish, light brackish and saline water in the NDA as a whole and in each governorate and the identification of the governorates that are most vulnerable to salinization. It is highly recommended that the results of this analysis are considered in future mitigation and/or adaptation plans.

Density-dependent 3D FE modelling of a recharge drain to mitigate saltwater contamination at the Venice farmland

2021 ◽  
Author(s):  
Maria Elisa Travaglino ◽  
Pietro Teatini
Keyword(s):  
Coastal Aquifers ◽  
Saltwater Intrusion ◽  
Sea Water ◽  
Transport Model ◽  
Saline Water ◽  
Numerical Models ◽  
Groundwater Resources ◽  
Fe Modelling ◽  
Fresh Groundwater ◽  
Density Dependent

<p>Saltwater intrusion in coastal aquifers is one of the most challenging and worldwide environmental problems, severely affected by human activities and climate change. It represents a threat to the quality and sustainability of fresh groundwater resources in coastal aquifers. Saline water is the most common pollutant in fresh groundwater which can also compromise the agriculture and the economy of the affected regions. Therefore, it is necessary to develop engineering solutions to restore groundwater quality or at least to prevent further degradation of its quality.</p><p>For this purpose, the goal of the Interreg Italy – Croatia MoST (MOnitoring Sea-water intrusion in coastal aquifers and Testing pilot projects for its mitigation) project is to test possible solutions (such as underground barriers, cut-off walls, recharge wells and recharge drains) against saltwater intrusion properly supported by field characterization, laboratory experiments, monitoring of hydrological parameters, and numerical models.</p><p>This works shows the preliminary results of an ongoing modelling study carried out for a coastal farmland at Ca’ Pasqua, in the southern part of the Venice lagoon, in Italy. A three-dimensional finite-element density-dependent groundwater flow and transport model is developed to simulate the dynamics of saltwater intrusion in this lowlying area. The model is used to assess the potential effects of a recharge drain recently established at 1.5 m depth along a sandy paleochannel crossing the organic-silty area. The goal of the intervention is to mitigate the soil and groundwater salinization by spreading freshwater supplied by a nearby canal. The beneficial consequences of the recharge drain should be enhanced by the higher permeability of the paleochannel.</p>

scholarly journals Groundwater Resources from Eastern Romania under Human and Climatic Pressure

2020 ◽  
Vol 12 (24) ◽  
pp. 10341
Author(s):  
Ionuț Minea ◽  
Marina Iosub ◽  
Daniel Boicu
Keyword(s):  
Climate Changes ◽  
Groundwater Resources ◽  
Regional Climate ◽  
Negative Effects ◽  
Human Pressure ◽  
Groundwater Exploitation ◽  
North Part ◽  
Two Parameters ◽  
Pressure On Water Resources

Groundwater resources from a region may be subject to complex human and climatic pressure. The present study tries to analyze the human and climatic pressure on the groundwater resources from the eastern part of Romania, between 1983 and 2017, for seven groundwater bodies. Two parameters, the groundwater exploitation index (GWEI) and the Standardized Groundwater Index (SGI) for identifying hydrogeological droughts, were used to assess human and climatic pressure. The high values of GWEI show a significant increase in human pressure on water resources in recent decades, in lower and more populated areas, from the south and north part of de region, amid increasing investment in agriculture. In the case of climate pressure, the SGI values show significant values for the years 1983, 2000, 2007, and 2012. However, the overlap of hydrogeological droughts with an increase in human pressure can have a significant impact on the groundwater resources from this region, with negative effects in the mid and long term, under the growing effects of the regional climate changes.

scholarly journals Spatial and Temporal Changes of Groundwater Storage in the Quaternary Aquifer, UAE

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 864
Author(s):  
Mohsen Sherif ◽  
Ahmed Sefelnasr ◽  
Abdel Azim Ebraheem ◽  
Mohamed Al Mulla ◽  
Mohamed Alzaabi ◽  
...  
Keyword(s):  
Water Resources ◽  
Brackish Water ◽  
Initial Conditions ◽  
Groundwater Resources ◽  
Effective Porosity ◽  
Groundwater Storage ◽  
Fresh Groundwater ◽  
Groundwater Exploitation ◽  
Quaternary Aquifer ◽  
Groundwater Levels

To study the temporal and spatial variations of the groundwater quantity and quality in response to intensive groundwater exploitation from the Quaternary aquifer in UAE, a water budget model with a cell size of one km2 was developed. The available historical records of groundwater levels and salinity have been used to develop the water table and salinity maps of UAE for the years 1969, 2005, 2010, and 2015. The available water resources and soil information system was used to facilitate validity, cogency, and consistency of the groundwater analysis. The spatial analysis module of GIS was used to define the aquifer setting, saturated thickness, aquifer base elevation, effective porosity, and groundwater salinity at each grid cell. The obtained results indicated that the volume of fresh groundwater resources in the Quaternary aquifer in UAE has decreased from 238 km3 in 1969 to around 10 km3 in 2015. A major part of these depleted fresh groundwater resources was replaced by brackish water, and, therefore, the total groundwater storage in this aquifer has only decreased from 977 in 1969 to 922 km3 in 2015, respectively. If the same groundwater exploitation continues, the freshwater storage in the surficial aquifer might be totally depleted in agricultural areas. Most probably, the brackish groundwater resources will be exploited. In such areas, more attention should be devoted to the management of brackish water resources to avoid the exacerbation of the saltwater intrusion problem. Despite the fact that the obtained results indicate the negative impacts of the improper water resources management in a small part of the arid area, the learned lessons are valid for other arid countries, in particular, using the proper steady state boundary conditions for the initial conditions in modeling the available future management alternatives.

scholarly journals Direct or indirect recharge on groundwater in the middle-latitude desert of Otindag, China?

2018 ◽  
Author(s):  
Bing-Qi Zhu ◽  
Xiao-Zong Ren ◽  
Patrick Rioual
Keyword(s):  
Asian Summer Monsoon ◽  
Groundwater Resources ◽  
Atmospheric Precipitation ◽  
Middle Latitude ◽  
Northern China ◽  
Suture Zone ◽  
Mountain Areas ◽  
Fresh Groundwater ◽  
Groundwater Exploitation ◽  
Desert Zone

Abstract. The Otindag Desert in the middle-latitude desert zone of northern Hemisphere (NH) is essential to livestock-economy and ecoenvironment of northern China. Many areas in this zone are unexpectedly rich with groundwater resources although they have been under arid or hyper-arid climate for a long time. Widespread fresh groundwater deep to 60 m was found at the eastern part of the Otindag Desert. The occurrence of this massive fresh groundwater raises doubts on the long-lasting hypothesis in academic circles that regional atmospheric precipitation or palaeowater, namely the direct recharge, is the source of water in the middle-latitude desert aquifers of northern China. Understanding of the recharge of this fresh groundwater is important in evaluating the feasibility of groundwater exploitation and utilization. In this study we conducted hydrogeochemical and isotopical analyses to assess possible origin and recharge of these groundwaters. The analytical results indicate that the fresh groundwater is neither originated from regional atmospheric precipitation derived from the Asian Summer Monsoon system, nor from palaeowater that formed during the last glacial period. These findings suggest that the groundwater in this desert is possible to originate from remote mountain areas via the faults of the Solonker Suture zone, including the Daxing’Anlin and Yinshan Mountains. In addition, it is concluded that the hygeodrological linkage between desert aquifers and mountain systems through the suture zone is crucial to the hydrological functioning of the Otindag aquifer. This suggests that the modern indirect recharge mechanism, instead of the direct recharge and the palaeo-water recharge, is the most significant for groundwaterrecharge in the Otindag Desert. This study provides a new perspective into the origin and evolution of groundwater resources in the middle-latitude desert zone of HA.

Groundwater and salinization risk: tapping works and management experience in the Mediterranean Area

2021 ◽  
Author(s):  
Giorgio De Giorgio ◽  
Livia Emanuela Zuffianò ◽  
Maurizio Polemio
Keyword(s):  
Seawater Intrusion ◽  
Coastal Aquifers ◽  
Groundwater Resources ◽  
Regional Scale ◽  
Mediterranean Area ◽  
Management Approach ◽  
Fresh Groundwater ◽  
Groundwater Exploitation ◽  
Saline Groundwater ◽  
The Mediterranean

<p>The progressive population growth in coastal areas constitutes a huge worldwide problem, particularly relevant for coastal aquifers of the Mediterranean basin.</p><p>The increasing use of groundwater and the effect of seawater intrusion makes the study of coastal aquifers extremely relevant.</p><p>There are various measures, practices, and actions throughout the world for managing groundwater when this natural resource is subject to salinization risk.</p><p>This research focused on the seawater intrusion, classifies the different practical solutions protecting the groundwater through salinization mitigation and/or groundwater salinity improvements along the Mediterranean Area.</p><p>The literature review was based on 300 papers, which are mainly international journal articles (76%). The rest includes conference papers (11.8%), reports and theses (7%), and books or chapters of a book (25%).</p><p>Three main schematic groundwater management approaches can be distinguished for the use of groundwater resources at risk of salinization.</p><p>The <strong>engineering approaches</strong> pursue locally the discharge increase avoiding or controlling the salinity increase.</p><p>The most recent experiences of tapping submarine springs were realized using underground concrete dams, tools shaped like a parachute or tulip, or a fiberglass telescopic tube-bell, especially in the case of karstic aquifers.</p><p>The current widespread form of the engineering approach is to address the issue of groundwater exploitation by wells.</p><p>More complex solutions use subhorizontal designs. Subhorizontal tapping schemes were realized using tunneling and/or boring in combination with wide-diameter wells or shafts.</p><p>These works include horizontal drains or radial tunnels bored inside the saturated aquifer, shafts excavated down to the sea level with radial galleries or drains realized together with weirs to improve the regulation of the discharge rate and of salinization. Application of these solutions in areas where a thin fresh groundwater lens floats on the saline groundwater, as in the case of narrow and highly permeable islands, can yield high discharges, thus causing a very low drawdown over very wide areas. These solutions were successfully applied in Malta Islands.</p><p>The <strong>discharge management approach</strong> encompasses at least an entire coastal aquifer and defines rules concerning groundwater utilization and well discharge.</p><p>A multi-methodological approach based on monitoring networks, spatiotemporal analysis of groundwater quality changes, and multiparameter well logging is described in Apulian karstic coastal aquifers (Italy). The core is the definition of the salinity threshold value between pure fresh groundwater and saline groundwater mixture. The basic tools were defined to be simple and cost-effective to be applicable to the widest range of situations.</p><p>The <strong>water and land management approach</strong> should be applied on a regional scale. The main choice for this approach is pursuing water-saving measures and water demand adaptation. A multiple-users and multiple-resources-water supply system model was implemented to evaluate the effectiveness of the increasing maximum capacity of the surface reservoir and managed aquifer recharge in Apulia, a semi-arid region of Southern Italy.</p>

scholarly journals Anthropogenic depletion of Iran’s aquifers

2021 ◽  
Vol 118 (25) ◽  
pp. e2024221118
Author(s):  
Roohollah Noori ◽  
Mohsen Maghrebi ◽  
Ali Mirchi ◽  
Qiuhong Tang ◽  
Rabin Bhattarai ◽  
...  
Keyword(s):  
Spatial Scales ◽  
Groundwater Resources ◽  
Water Security ◽  
Groundwater Depletion ◽  
Groundwater Extraction ◽  
Environmental Implications ◽  
Annual Average ◽  
Fresh Groundwater ◽  
In Situ Data ◽  
Groundwater Supply

Global groundwater assessments rank Iran among countries with the highest groundwater depletion rate using coarse spatial scales that hinder detection of regional imbalances between renewable groundwater supply and human withdrawals. Herein, we use in situ data from 12,230 piezometers, 14,856 observation wells, and groundwater extraction points to provide ground-based evidence about Iran’s widespread groundwater depletion and salinity problems. While the number of groundwater extraction points increased by 84.9% from 546,000 in 2002 to over a million in 2015, the annual groundwater withdrawal decreased by 18% (from 74.6 to 61.3 km3/y) primarily due to physical limits to fresh groundwater resources (i.e., depletion and/or salinization). On average, withdrawing 5.4 km3/y of nonrenewable water caused groundwater tables to decline 10 to 100 cm/y in different regions, averaging 49 cm/y across the country. This caused elevated annual average electrical conductivity (EC) of groundwater in vast arid/semiarid areas of central and eastern Iran (16 out of 30 subbasins), indicating “very high salinity hazard” for irrigation water. The annual average EC values were generally lower in the wetter northern and western regions, where groundwater EC improvements were detected in rare cases. Our results based on high-resolution groundwater measurements reveal alarming water security threats associated with declining fresh groundwater quantity and quality due to many years of unsustainable use. Our analysis offers insights into the environmental implications and limitations of water-intensive development plans that other water-scarce countries might adopt.

Development and Applications of a Wellhead Protection Area Delineation Computer Program

1991 ◽  
Vol 24 (11) ◽  
pp. 51-62 ◽  
Author(s):  
N. Guiguer ◽  
T. Franz
Keyword(s):  
Case History ◽  
Numerical Models ◽  
Groundwater Resources ◽  
Theoretical Background ◽  
Human Interaction ◽  
Wellhead Protection ◽  
First Case ◽  
Protection Area ◽  
And Storage ◽  
The Town

In the last few years, groundwater management has concentrated on the protection of groundwater quality. An increasing number of countries has adopted policies to protect vital groundwater resources from deterioration by regulating human interaction with the subsurface, the use of potential contaminants, land use restrictions, and waste transport and storage. One of the more common regulatory approaches to the protection of groundwater focuses on public water supplies to reduce the potential of human exposure to hazardous contaminants. Under the framework of the Safe Drinking Water Act amended by U.S. Congress in 1986, The U.S.EPA (1987) issued guidelines for the delineation of wellhead protection areas, recommending the use of analytical and numerical models for the identification of such areas. In this study, the theoretical background for the development of one such numerical model is presented. Two real-world applications are discussed: in the first case history, the model is applied to a Superfund Site in Puerto Rico as a tool for assessment of the effectiveness of a proposed pump-and-treat scheme for aquifer remediation. Based on simulation results for the evolution of the existing contaminant plume it was verified that such a scheme would not work with the proposed purging wells. The second case history is the delineation of a wellhead protection area in the Town of Littleton, Massachusetts, and subsequent design of a monitoring well network.

Antarctic Climate History and Global Climate Changes

2017 ◽  
Author(s):  
Pontus Lurcock ◽  
Fabio Florindo
Keyword(s):  
Ocean Circulation ◽  
Climate Changes ◽  
Numerical Models ◽  
Global Climate ◽  
Sediment Cores ◽  
Ice Sheets ◽  
Global Ocean ◽  
Climate History ◽  
Global Climate Changes ◽  
Planetary Albedo

Antarctic climate changes have been reconstructed from ice and sediment cores and numerical models (which also predict future changes). Major ice sheets first appeared 34 million years ago (Ma) and fluctuated throughout the Oligocene, with an overall cooling trend. Ice volume more than doubled at the Oligocene-Miocene boundary. Fluctuating Miocene temperatures peaked at 17–14 Ma, followed by dramatic cooling. Cooling continued through the Pliocene and Pleistocene, with another major glacial expansion at 3–2 Ma. Several interacting drivers control Antarctic climate. On timescales of 10,000–100,000 years, insolation varies with orbital cycles, causing periodic climate variations. Opening of Southern Ocean gateways produced a circumpolar current that thermally isolated Antarctica. Declining atmospheric CO2 triggered Cenozoic glaciation. Antarctic glaciations affect global climate by lowering sea level, intensifying atmospheric circulation, and increasing planetary albedo. Ice sheets interact with ocean water, forming water masses that play a key role in global ocean circulation.

Sign in / Sign up

Export Citation Format

Share Document