نتایج جستجو برای: groundwater loss

تعداد نتایج: 473115  

2006
Sushil K. Singh

A head loss concept, new to the stream-aquifer interaction, is introduced for modeling laboratory observations. Using this concept, the equation applicable to fully penetrating streams is modified to account for the head loss at the entrance. The modified model is able to explain and fit the observed laboratory data correctly. Equations are proposed to calculate the hydraulic diffusivity of aqu...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2014
Sarah K Wexler Christine L Goodale Kevin J McGuire Scott W Bailey Peter M Groffman

Despite decades of measurements, the nitrogen balance of temperate forest catchments remains poorly understood. Atmospheric nitrogen deposition often greatly exceeds streamwater nitrogen losses; the fate of the remaining nitrogen is highly uncertain. Gaseous losses of nitrogen to denitrification are especially poorly documented and are often ignored. Here, we provide isotopic evidence (δ(15)NNO...

Journal: :Environmental pollution 2007
A Visser H P Broers B van der Grift M F P Bierkens

Recent EU legislation is directed to reverse the upward trends in the concentrations of agricultural pollutants in groundwater. However, uncertainty of the groundwater travel time towards the screens of the groundwater quality monitoring networks complicates the demonstration of trend reversal. We investigated whether trend reversal can be demonstrated by relating concentrations of pollutants i...

2016
Mahfuzur R Khan Mohammad Koneshloo Peter S K Knappett Kazi M Ahmed Benjamin C Bostick Brian J Mailloux Rajib H Mozumder Anwar Zahid Charles F Harvey Alexander van Geen Holly A Michael

Many of the world's megacities depend on groundwater from geologically complex aquifers that are over-exploited and threatened by contamination. Here, using the example of Dhaka, Bangladesh, we illustrate how interactions between aquifer heterogeneity and groundwater exploitation jeopardize groundwater resources regionally. Groundwater pumping in Dhaka has caused large-scale drawdown that exten...

2011
Ying Ouyang

Pollution of rivers with excess nutrients due to groundwater discharge, storm water runoff, surface loading, and atmospheric deposition is an increasing environmental concern worldwide. While the storm water runoff and surface loading of nutrients into many rivers have been explored in great detailed, the groundwater discharge of nutrients into the rivers has not yet been thoroughly quantified....

2006
E. A. Mohamed

Compartmentalisation, the subdivision of an aquifer into discrete and relatively isolated units, may be of critical importance for the protection of groundwater although it has been largely ignored in the groundwater literature. The Lower Triassic Sherwood Sandstone, in north west of England, UK, may be a good example of an aquifer that has been compartmentalised by numerous high angle faults w...

2015
Dhafer Alsalah Nada Al-Jassim Kenda Timraz Pei-Ying Hong Paul B. Tchounwou

This study examines the groundwater quality in wells situated near agricultural fields in Saudi Arabia. Fruits (e.g., tomato and green pepper) irrigated with groundwater were also assessed for the occurrence of opportunistic pathogens to determine if food safety was compromised by the groundwater. The amount of total nitrogen in most of the groundwater samples exceeded the 15 mg/L permissible l...

2017
Weiwei Shao Jinjun Zhou Jiahong Liu Haixing Zhang Jianhua Wang Chenyao Xiang Guiyu Yang Yun Tang

The comprehensive treatment project of groundwater over-exploitation in Hebei Province has been implemented for more than a year, and the effect of exploitation restriction is in urgent need of evaluation. This paper deals with Cheng'an County of Hebei Province as the research subject. Based on collected hydro-meteorological, socioeconomic, groundwater, and other related data, together with typ...

2011
Xiao Liang Pieter van Dijk

Since groundwater is diminishing rapidly in rural Beijing, rainwater harvesting for irrigation is being promoted. As the cost of pumping up groundwater is low, farmers have few incentives to use rainwater. To promote the consumption of rainwater, the Beijing Water Authority may in the future raise the cost of using groundwater by introducing a charge. Higher cost of groundwater will increase th...

2016
Brian F. Thomas Ali Behrangi James S. Famiglietti Thomas M. Missimer

Episodic recharge as a result of infrequent, high intensity precipitation events comprises the bulk of groundwater recharge in arid environments. Climate change and shifts in precipitation intensity will affect groundwater continuity, thus altering groundwater recharge. This study aims to identify changes in the ratio of groundwater recharge and precipitation, the R:P ratio, in the arid southwe...

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