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essay格式范文:地下水的治理使用问题

时间:2015-11-24 17:13来源:www.ukassignment.org 作者:留学作业网 点击:
essay格式范文:地下水的治理使用问题
Governance issues in managing groundwater use
 
水是生物生存的重要资源,包括人和人类。超过71%的地球表面被水覆盖。不同地区的淡水分布不均匀。淡水资源被认为是一种稀缺资源,其质量随着使用和治理结构的不合理而日益恶化。世界面临的主要问题不是水量,而是世界的有效管理和安全配置。特别是,地下水由于它的性质和在世界许多地区的密集使用,因而更容易受到污染,消耗和许多其他问题。地下水构成约97%的所有淡水有可能供人类使用(1999)。在世界的许多地方,地下水资源是人类需要的清洁饮用水的主要来源,因为可以用相当低的成本来利用它。他们利用地下水来满足他们的饮用水、生活、工业、灌溉和其他一些需要。过度开发,快速的工业化,农业的做法不当化学浸出到地下水储量和对地下水的不当治理已经恶化了世界许多地方的地下水质量。一旦污染,对地下水的补救是非常昂贵的。在世界许多地方,为了灌溉而过度使用地下水已经贫化了地下水位。
 
简介-Introduction
 
Water is a vital resource for the survival of all living beings including man and mankind. More than 71 % of the earth's surface is covered with water. The distribution of freshwater is non-uniform in the different parts of the continents. The freshwater resource is considered as a scarce resource as its quality is getting deteriorated with the increasing use and improper governance structure. The main problem that the world faces is not the water quantity but its effective management and safe allocation worldwide. Particularly, groundwater is much more vulnerable to the pollution, depletion and many others problems due to its nature and intensive use in many parts of the world. Groundwater constitutes about 97% of all freshwater potentially available for human use (Foster, 1999). In many parts of the world, groundwater resources are the main source of clean and potable water for human needs as it is can be exploited with quite low cost. They use groundwater to fulfill their drinking, domestic, industrial, irrigation and several other needs. Overexploitation, rapid industrialization, improper agricultural practices with chemical leaching into the groundwater reserves and poor groundwater governance has deteriorated the quality of groundwater in many parts of the world . Once polluted the remedy of pollutants from the groundwater is extremely expensive. The excessive use of Groundwater for irrigation purpose has also depleted groundwater table in many parts of the world.
 
The main objective of this paper is to understand the characteristics of the groundwater and the issues of groundwater governance and its management. The paper tries to give an overview of the important elements of the groundwater governance and the challenges and opportunities of institutionalizing the groundwater development. Groundwater governance in Nepal has been taken as an example to represent the situation of current groundwater management in South-Asian countries. It tries to deal with the question: why groundwater development has remained at infancy in Nepal despite of having tremendous groundwater potential? Policies, institutions and structure of groundwater governance and economics of groundwater are also dealt in the following sections, terminating with the overall conclusion of the paper.
 
地下水体系的本质-Groundwater system in nature
 
The freshwater in the earth comes from the precipitation in different forms such as rain, snowfall, melting ice etc. Precipitation then by means of stream flow or runoff reaches to the rivers and finally flows to the sea or ocean. A part of precipitation infiltrates into the soil through subsurface routes and accumulates in the form of aquifers or groundwater above the impermeable bed of earth's crust. The water contained in the aquifers also contributes to the base flow in many rivers, wetlands and oceans. Therefore the groundwater system can be considered as an important part of the hydrological cycle. The groundwater aquifers are often well protected by the layers of soil and sediment, which effectively filter rain water as it percolates through and removes the particulate matters, pathogenic microbes and several chemical constituents. Hence, it is normally considered to be safe for drinking and other household purposes in many parts of the world. Groundwater is termed as 'hidden sea'- sea because of large quantity and hidden because it is not visible, thus pollution pathways and processes are not readily perceived (Chapelle, 1997; Schmoll et.al, 2006). The replenishment of the groundwater occurs at relatively slow rates and varies between different locations so that overexploitation readily brings serious quality concerns (Schmoll et.al, 2006).
 
Once an aquifer is seriously polluted, it may be difficult, costly or even technically impossible to reverse or remedy this so that timely governance solutions of a precautionary nature are very important (Scheumann, 2008). Due to distinctive nature and presence of groundwater inside the earth's surface there is little awareness among the people about the pollutant transport and flow into the groundwater. This leads to the serious health problems to the people depending on quality of groundwater consumed. Worldwide, a large population depends on the ground water for drinking purpose and the trend of increasing dependence of growing population on groundwater is continuously rising.
 
地下水的使用及影响-Use of groundwater and its implications
 
Groundwater has been considered as a common pool resource with extremely high use value as well as inherently vulnerable (Myint, 1999). Groundwater resource has a complex flow nature with little or no reliable information on the quality, quantity and extent of contamination. It can be easily exploited by using the simple equipments and tapping procedures for e.g. using wells and pumps. The individual users are unaware about the actual value of this resource as they do not have to pay additionally for the water derived from the underground reserves positioned in their land. The poor understanding of the groundwater aquifers among the users has put this resource under extreme vulnerable condition and contamination by various pollutants.
 
About 20% of all the global water use comes from groundwater resources and over 60% of the world's population depends on groundwater for their drinking and domestic water uses. Agriculture sector, which consumes over 80% of the total water used by man, is depending increasingly on groundwater resources (Upadhyay, 2008). Groundwater is mainly used for drinking and other household purposes, irrigation, industrial purposes, nourishing and maintaining fragile ecosystem (e.g. wetlands), various domestic purposes, as well as recreational activities. Its use for irrigation is rising tremendously for increasing the agricultural production to meet the food demand of world's population. People find groundwater as easier and cheaper freshwater resource to exploit than using the surface water because of simple drilling technologies for extraction of water from groundwater reservoirs. Especially for the poor people living in rural areas, groundwater is only a source of freshwater needed for various purposes including drinking, irrigation and other household purposes. Several such existing examples can be observed in the rural villages of the South-Asian countries. About 1.5 billion people depend on groundwater for drinking purpose (www.groundwater.org). Worldwide 1.2 billion people lack safe, sanitary and secure water supplies and approximately 5 million people die yearly from water borne diseases, and the water demand is increasing three times as fast as the world's population growth rate. (Durant et. al., "w.y.").
 
groundwater is susceptible to contamination by several harmful pathogens such as bacteria, viruses from septic and landfill systems and various source of pollutants such as toxic compounds from pesticides, chemicals, fertilizers, industrial effluents, road salts, gasoline, mining sites, motor oil, hazardous waste sites etc. that may seep or percolate into groundwater and make it unsafe for human use causing different health hazards. Therefore, it is very important for human welfare to protect the groundwater reserves from getting contaminated. Smaller communities could be prepared to conduct a contaminant source inventory (CSI) using various techniques, such as geographic information systems (GIS) and global positioning systems (GPS) which allow communities to accurately obtain, manage, and update data that help identify potential contaminant sources within a source water protection area(www.groundwater.org). There is need for the effective implementation of the groundwater policies and institutions and good groundwater governance.
 
While withdrawing groundwater it is important to ensure no disturbance in the natural environment such as balanced wetlands and groundwater table. At the same time, quality and quantity of water in the adjacent wells, streams, lakes, rivers, springs etc. must be maintained. Because the movement of groundwater does not respect municipal boundaries, it makes sense that the state is the entity that can regulate or restrict groundwater use by effective implementation of adequate groundwater acts (Anonymous, 2007).
 


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