نتایج جستجو برای: karst water

تعداد نتایج: 554389  

2016
Ke Chen Shengtian Yang Changsen Zhao Zongli Li Ya Luo Zhiwei Wang Xiaolin Liu Yabing Guan Juan Bai Qiuwen Zhou Xinyi Yu Athanasios Loukas

Vegetation deterioration and soil loss are the main causes of more precipitation leakages and surface water shortages in degraded karst areas. In order to improve the utilization of water resources in such regions, water storage engineering has been considered; however, site selection and cost associated with the special karstic geological structure have made this difficult. According to the pr...

2011
Junhua Yan Y. P. Wang Guoyi Zhou Shenggong Li Guirui Yu Kun Li

[1] Using an estimated bicarbonate concentration ([HCO3 ]) in water and discharge rates of surface water and underground water from the Houzhai Basin, southwest China, from 1986 to 2007, we estimate that the mean carbon uptake rate was 20.7 g C m yr. The surface water and underground water contribute about equally to the total carbon uptake from 1986 to 2007. About 97% of the interannual variat...

2012
Carolyn Ball Jonathan B. Martin

Water is one of our most important resources. Both surface water and groundwater are used by humans for drinking, irrigation, transportation, entertainment, and are a major service for ecosystems. Almost all surface water features, such as streams, rivers, and lakes, interact with groundwater by exchanging water between these two reservoirs. Surface water can become polluted depending on land u...

2003
N. Dörfliger

ABSTRACT The French Mediterranean coastal aquifers are essentially alluvial, deep sedimentary and karst. Whereas the alluvial aquifers are particularly sensitive to salt-water intru sion, contamination of the deep aquifers is generally due to vertical hydraulic connec tion with the shallow aquifers. As for the karst systems, which are quite well developed f rom Languedoc-Roussillon to Provence-...

The karst areas refers to individual areas that shaped by the dissolution of bedrock and subsurface drainage grid development and are connected mainly with limestone. The karstic formations outcrop 20 percent of the land surface of the planet is covered that 11 percent of Iran are part of this 20% is included. The ZAGROS region of origin karstic formations in the country that the formation of k...

2017
Michel Bakalowicz P. Fleury Bruno Jouvencel Jean-Jacques Promé P. Becker Thierry Carlin Nathalie Dörfliger Jean-Luc Seidel Philippe Sergent

In coastal regions, the study of karst aquifers and the ground water resource exploitation require a specific methodology and exploration and monitoring techniques. Two directions are investigated, leading to new technological and methodological developments. The first investigation axis deals with the exploration of fresh water plumes from submarine karst springs. An Autonomous Underwater Vehi...

2017
Ernesto Medina Elvira Cuevas Ariel E. Lugo

Forests on calcareous substrates constitute a large fraction of the vegetation in Puerto Rico. Plant growth on these substrates may be affected by nutrient deficiencies, mainly P and Fe, resulting from high pH and formation of insoluble compounds of these elements. The occurrence of these forests in humid and dry areas provides an opportunity to compare nutrient relations, water use efficiency,...

2006
Jennifer M. Martin Elizabeth J. Screaton Jonathan B. Martin

Karst aquifers with high primary-porosity matrix, such as the Floridan aquifer, have the potential for movement of water between conduits and matrix, with important implications for karst development and the maintenance of groundwater quality. The Santa Fe River Sink and River Rise conduit system, along with the surrounding unconfined Floridan aquifer in north-central Florida, provides a study ...

Journal: :پژوهش های جغرافیای طبیعی 0
مهران مقصودی دانشیار ژئومورفولوژی، دانشگاه تهران هانیه اخوان دانشجوی کارشناسی ارشد ژئومورفولوژی، دانشگاه تهران مجتبی مهدیان ماهفروزی دانشجوی کارشناسی ارشد اقلیم شناسی، دانشگاه تهران غدیر عشورنژاد دانشجوی دکتری، سنجش از دور و سامانة اطلاعات جغرافیایی دانشگاه تهران

introduction the iran has vast areas of karst landforms due to the relatively high carbonaceous rocks deposited during different geologic eras. karst landforms are noteworthy for investigation from many aspects. the primary importance of these regions is the considerable amount of underground water stored in karst formations. these reserves are favorable, both in quality and quantity, as natura...

2014
MaryLynn Musgrove Brian G Katz Lynne S Fahlquist Christy A Crandall Richard J Lindgren

Karst aquifers occur in a range of climatic and geologic settings. Nonetheless, they are commonly characterized by their vulnerability to water-quality impairment. Two karst aquifers, the Edwards aquifer in south-central Texas and the Upper Floridan aquifer in western Florida, were investigated to assess factors that control the movement of contaminants to public-supply wells (PSWs). The geoche...

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