نتایج جستجو برای: karst

تعداد نتایج: 4636  

2012
Yonghong Hao Jiaojuan Zhao Huamin Li Bibo Cao Zhongtang Li Tian-Chyi J. Yeh

The karst hydrological processes are the response of karst groundwater system to precipitation. This study provided a concept model of karst hydrological processes. The hydraulic response time of spring discharge to precipitation includes the time that precipitation penetrates through the vadose zone, and the subsequent groundwater pressure wave propagates to a spring outlet. Due to heterogenei...

2017
Stuart V Nielsen Paul M Oliver

Exposed limestone karst landscapes, especially in the tropics, are often home to distinctive and specialized biotas. Among vertebrates, a particularly large number of karst-associated lizard taxa have been described, but for the vast majority, evidence of specific adaptions to karst is lacking. A number of studies, however, have provided evidence of consistent morphological trends in lizards th...

2006
Yonghong Hao Tian-Chyi J. Yeh Caihong Hu Yanrong Wang Xia Li

Karst regions, occupy approximately 25% of the land surface of the earth. Karst aquifers are often major sources of water supply in these areas. However, karst aquifers are generally considered to be particularly vulnerable to pollution and anthropogenic impacts. Large withdrawals of water in karst areas for municipal, agricultural, and industrial use may competitively affect water supply in su...

1999
N. Doerfliger P. - Y. Jeannin F. Zwahlen

Groundwater resources from karst aquifers play a major role in the water supply in karst areas in the world, such as in Switzerland. Defining groundwater protection zones in karst environment is frequently not founded on a solid hydrogeological basis. Protection zones are often inadequate and as a result they may be ineffective. In order to improve this situation, the Federal Office for Environ...

2002
Yongli Gao

Southeastern Minnesota is part of the Upper Mississippi Valley Karst (Hedges & Alexander 1985) that includes southwestern Wisconsin and northeastern Iowa. Karst lands in Minnesota developed in Paleozoic carbonate and sandstone bedrock. A significant sandstone karst has developed in Pine County (Shade et al. 2000). Most surficial karst features, such as sinkholes, are only in those areas with le...

Journal: :پژوهش های جغرافیای طبیعی 0
محمد صدیق قربانی استادیار گروه جغرافیا، دانشگاه پیام نور

introduction in several perspectives including geographical determinism, possibilism, exceptionalism, ecological and other views, it is discussed about understanding how human and the environment interact. human in dealing with different environments, depending on the capabilities of environment and existing tools and techniques, adopt themselves with the nature or interfere in it. karst landsc...

Journal: :Zootaxa 2013
L Lee Grismer Perry L Wood Maketab Mohamed Kin Onn Chan Heather M Heinz Alex S-I Sumarli Jacob A Chan Ariel I Loredo

A new species of karst-adapted gekkonid lizard of the genus Cnemaspis Strauch is described from Gua Gunting and Gua Goyang in a karst region of Merapoh, Pahang, Peninsular Malaysia whose unique limestone formations are in immediate danger of being quarried. The new species differs from all other species of Cnemaspis based on its unique suite of morphological and color pattern characters. Its di...

2016
Bo Liu Reza Malekian Jinpeng Xu

Karst collapse columns, as a potential water passageway for mine water inrush, are always considered a critical problem for the development of deep mining techniques. This study aims to identify the mixing process of groundwater deriving two different limestone karst-fissure aquifer systems. Based on analysis of mining groundwater hydrogeochemical properties, hydraulic connection between the ka...

Journal: :Ground water 2007
Yonghong Hao Tian-Chyi J Yeh Yanrong Wang Ying Zhao

There are approximately 470,000 km(2) of karst aquifers that feed many large springs in North China. Turbulent flow often exists in these karst aquifers, which means that the classical ground water model based on Darcy's law cannot be applied here. Ground water data are rare for these aquifers. As a consequence, it is difficult to quantitatively investigate ground water flow in these karst syst...

2008
Y. M. Yue K. L. Wang Z. C. Chen Y. Z. Yu

Karst rocky desertification is a special kind of land desertification developed under violent human impacts on the vulnerable ecogeo-environment in karst ecosystem. The process of karst rocky desertification results in simultaneous and complex variations of many interrelated soil, rock and vegetation biophysical parameters, rendering it difficult to develop simple and robust remote sensing mapp...

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