4,401 research outputs found

    Groundwater research and management: integrating science into management decisions. Proceedings of IWMI-ITP-NIH International Workshop on "Creating Synergy Between Groundwater Research and Management in South and Southeast Asia," Roorkee, India, 8-9 February 2005

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    Groundwater management / Governance / Groundwater development / Artificial recharge / Water quality / Aquifers / Groundwater irrigation / Water balance / Simulation models / Watershed management / Water harvesting / Decision making / South East Asia / Bangladesh / China / India / Nepal / Pakistan / Syria

    Reconnaissance Survey of Arsenic Concentration in Ground-water in South-eastern Ghana

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    Arsenic (As) analysis of 150 boreholes in the south-eastern part of Ghana (Accra, Eastern and Volta regions) revealed low to medium concentrations in the range of 2-39 mg l-1, with only 2% of boreholes tested having arsenic concentration exceeding 10 mg l-1 of the WHO (2004) maximum permissible level of arsenic in drinking water. The measurements were carried out in the field using the Wagtech Arsenator field test kit (Wag-We 100500) equipment, which gives direct readout of arsenic concentration in the critical range 2-100 mg l-1. Arsenic concentrations were in the range < 2–39 mg l-1 with mean (< 2 mg l-1) and median (< 2 mg l-1). Out of 150 samples analysed, 147 had As concentration below 10 mg l-1. Three boreholes in the Recent Sand Formation in southern Volta Region at Atitekpo, Mafi Devime and Woe Aklorbordzi had arsenic concentrations of 28 mg l-1, 19 mg l-1 and 39 mg l-1, respectively. Though the sample of boreholes tested was only approximately 10% of the total number of boreholes in the study, the distribution within the sample makes the generalization that the risk of arsenic contamination of rural water supply in southeastern Ghana is generally low plausible. In spite of this assertion, boreholes in the Recent Sandy Formation have to be critically assessed to determine the extent of arsenic contamination and, if possible, monitored.West African Journal of Applied Ecology Vol. 13 2008: pp. 16-2

    Water Security for Climate Resilience Report: A synthesis of research from the Oxford University REACH programme

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    This report presents a synthesis of published and ongoing research by REACH which explores the relationship between water security, climate and climate adaptation decisions, drawing on findings from REACH research conducted in Sub-Saharan Africa and South Asia. We demonstrate the unequal impact of climate on water security, and on people’s lives and livelihoods, which can be counter-intuitive to broad narratives around resilience and adaptation. We exemplify the impact of seasonal fluctuations in weather on surface and groundwater quality and quantity, and show that water security risks evolve with shifting climate conditions, water use behaviours, and policy decisions. We also present a deepened understanding of location- and context specific climate issues and dynamics, revealing a pressing need to consider and plan for different distributional impacts of climate and climate change

    How serious are groundwater over-exploitation problems in India?: a fresh investigation into an old issue

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    Groundwater developmentAssessmentRechargeAquifersWater balanceWellsTube wellsPumpingCostsEconomic impact

    Groundwater resources in the Indo-Gangetic Basin : resilience to climate change and abstraction

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    Groundwater within the Indo‐Gangetic Basin (IGB) alluvial aquifer system forms one of the world’s most important and heavily exploited reservoirs of freshwater. In this study we have examined the groundwater system through the lens of its resilience to change – both from the impact of climate change and increases in abstraction. This has led to the development of a series of new maps for the IGB aquifer, building on existing datasets held in Pakistan, India, Nepal and Bangladesh, a review of approximately 500 reports and papers, and three targeted field studies on under‐researched topics within the region. The major findings of the study are described below. The IGB groundwater system 1. The IGB alluvial aquifer system comprises a large volume of heterogeneous unconsolidated sediment in a complex environmental setting. Annual rainfall varies from 2000mm in the Bengal basin, and the system is dissected by the major river systems of the Indus, Ganges and Brahmaputra. The groundwater system has been modified by the introduction of large scale canal irrigation schemes using water from the Indus and Ganges since the 19th and early 20th centuries. 2. High yielding tubewells can be sustained in most parts of the alluvial aquifer system; permeability is often in the range of 10 – 60 m/d and specific yield (the drainable porosity) varies from 5 – 20%, making it highly productive. 3. High salinity and elevated arsenic concentrations exist in parts of the basin limiting the usefulness of the groundwater resource. Saline water predominates in the Lower Indus, and near to the coast in the Bengal Delta, and is also a major concern in the Middle Ganges and Upper Ganges (covering much of the Punjab Region in Pakistan, southern Punjab, Haryana and parts of Uttar Pradesh in India). Arsenic severely impacts the development of shallow groundwater in the fluvial influenced deltaic area of the Bengal Basin. 4. Recharge to the IGB aquifer system is substantial and dynamic, controlled by monsoonal rainfall, leakage from canals, river infiltration and irrigation returns. Recharge from rainfall can occur even with low annual rainfall (350 mm) and appears to dominate where rainfall is higher (> 750 mm). Canal leakage is also highly significant and constitutes the largest proportion of groundwater recharge in the drier parts of the aquifer, partially mitigating the effects of abstraction on groundwater storage. 5. Deep groundwater (>150 m) in the Bengal basin has strategic value for water supply, health and economic development. Excessive abstraction poses a greater threat to the quality of this deep groundwater than climate change. Heavy pumping may induce the downward migration of arsenic in parts of Bangladesh, and of saline water in coastal regions, but field evidence and modelling both suggest that deep groundwater abstraction for public water supply in southern Bangladesh is in general secure against widespread ingress of arsenic and saline water for at least 100 years
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