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Groundwater discharge

About: Groundwater discharge is a research topic. Over the lifetime, 4769 publications have been published within this topic receiving 108911 citations.


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Journal ArticleDOI
TL;DR: In this paper, the authors provided a global overview of groundwater depletion by assessing groundwater recharge with a global hydrological model and subtracting estimates of groundwater abstraction, and they estimated the total global groundwater depletion to have increased from 126 (±32) km3 a−1 in 1960 to 283 (±40) km 3 a −1 in 2000.
Abstract: [1] In regions with frequent water stress and large aquifer systems groundwater is often used as an additional water source. If groundwater abstraction exceeds the natural groundwater recharge for extensive areas and long times, overexploitation or persistent groundwater depletion occurs. Here we provide a global overview of groundwater depletion (here defined as abstraction in excess of recharge) by assessing groundwater recharge with a global hydrological model and subtracting estimates of groundwater abstraction. Restricting our analysis to sub-humid to arid areas we estimate the total global groundwater depletion to have increased from 126 (±32) km3 a−1 in 1960 to 283 (±40) km3 a−1 in 2000. The latter equals 39 (±10)% of the global yearly groundwater abstraction, 2 (±0.6)% of the global yearly groundwater recharge, 0.8 (±0.1)% of the global yearly continental runoff and 0.4 (±0.06)% of the global yearly evaporation, contributing a considerable amount of 0.8 (±0.1) mm a−1 to current sea-level rise.

1,367 citations

Journal ArticleDOI
TL;DR: A review of methods that are based on groundwater-level data is presented in this article, where the theory underlying the methods is explained and examples from the literature are used to illustrate applications of the different methods.
Abstract: Accurate estimation of groundwater recharge is extremely important for proper management of groundwater systems. Many different approaches exist for estimating recharge. This paper presents a review of methods that are based on groundwater-level data. The water-table fluctuation method may be the most widely used technique for estimating recharge; it requires knowledge of specific yield and changes in water levels over time. Advantages of this approach include its simplicity and an insensitivity to the mechanism by which water moves through the unsaturated zone. Uncertainty in estimates generated by this method relate to the limited accuracy with which specific yield can be determined and to the extent to which assumptions inherent in the method are valid. Other methods that use water levels (mostly based on the Darcy equation) are also described. The theory underlying the methods is explained. Examples from the literature are used to illustrate applications of the different methods.

1,080 citations

Journal ArticleDOI
18 Apr 1996-Nature
TL;DR: In this paper, the authors report large enrichments of 226Ra in coastal waters of the South Atlantic Bight and demonstrate that groundwater discharge is the main source of the 226Ra surplus, and conclude that the groundwater flux to these coastal waters must be about 40% of the river-water flux during the study period.
Abstract: THE flow of ground water directly into the coastal ocean has been studied previously by in situ measurements, seep meters and diffusion gradient models1. Although these techniques provide ample evidence that such flows occur, they do not provide a means of quantifying the groundwater flux on a regional scale. Here I report large enrichments of 226Ra in coastal waters of the South Atlantic Bight, and demonstrate that groundwater discharge is the main source of the 226Ra surplus. Using 226Ra data for brackish ground waters with estimates of residence times of nearshore waters, I conclude that the groundwater flux to these coastal waters must be about 40% of the river-water flux during the study period. Besides Ra, other metals, nutrients and organic compounds are expected to be enriched in brackish ground waters, so these findings require an upward revision of terrestrial fluxes of dissolved materials to these coastal waters, and perhaps a re-evaluation of such fluxes to the global ocean. These fluxes may be sensitive to hydrological factors, groundwater usage, dredging and sea-level change.

1,007 citations

Journal ArticleDOI
TL;DR: Sklash et al. as mentioned in this paper showed that groundwater plays a much more active, responsive and significant role in the generation, of storm and snow-melt runoff in streams than the recent literature on the subject suggests.

995 citations

Journal ArticleDOI
TL;DR: In this article, the authors proposed a system for artificial recharge of groundwater, which is achieved by putting surface water in basins, furrows, ditches, or other facilities where it infiltrates into the soil and moves downward to recharge aquifers.
Abstract: Artificial recharge of groundwater is achieved by putting surface water in basins, furrows, ditches, or other facilities where it infiltrates into the soil and moves downward to recharge aquifers. Artificial recharge is increasingly used for short- or long-term underground storage, where it has several advantages over surface storage, and in water reuse. Artificial recharge requires permeable surface soils. Where these are not available, trenches or shafts in the unsaturated zone can be used, or water can be directly injected into aquifers through wells. To design a system for artificial recharge of groundwater, infiltration rates of the soil must be determined and the unsaturated zone between land surface and the aquifer must be checked for adequate permeability and absence of polluted areas. The aquifer should be sufficiently transmissive to avoid excessive buildup of groundwater mounds. Knowledge of these conditions requires field investigations and, if no fatal flaws are detected, test basins to predict system performance. Water-quality issues must be evaluated, especially with respect to formation of clogging layers on basin bottoms or other infiltration surfaces, and to geochemical reactions in the aquifer. Clogging layers are managed by desilting or other pretreatment of the water, and by remedial techniques in the infiltration system, such as drying, scraping, disking, ripping, or other tillage. Recharge wells should be pumped periodically to backwash clogging layers. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s10040-001-0182-4.

880 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202347
202283
202194
2020102
2019100
2018124