Ground Water Department, Government of Andhra Pradesh, Hyderabad, 1-2-606/80/37, LIC Colony, Hyderabad, 500 080, India.
Environ Monit Assess. 2011 Feb;173(1-4):777-88. doi: 10.1007/s10661-010-1422-7. Epub 2010 Mar 31.
In India, groundwater assessment units are classified as overexploited areas, critical areas, semi-critical, or safe areas based on the stage of groundwater development and long-term water level trends. Intuitively, in the safe units, wells are expected to function and have good yields. Besides, in the safe units, new wells are expected to be successful. Conversely, the expectation of a successful well or wells with good yields is much lesser in the overexploited units. However, when these expectations are not met in the field, doubts are raised about the quality of assessment and its usefulness, and there is outright distrust on the agencies assessing groundwater resource by the common man as well as on the planners, administrators, and the politicians. Therefore, there is a need to present the results in a way that does not create confusion. One of the methods is to combine the assessment results with aquifer characters using geographic information system (GIS); when this is done, a whole set of newer classes emerge, which can be mapped. These classes are termed as groundwater typologies in this study. Each typology has some characteristics or traits in common, which include basic aquifer character as well as the stage of groundwater development. Thus, a class may be safe, but if the aquifer is poor, then it is separated from a class that is safe and where the aquifer is good and so on. In Andhra Pradesh, which is taken as the case study for this purpose, eight main typologies emerged, and two of these main typologies were further divided into four subtypologies each. This new way of understanding the pattern of groundwater abstraction (using GIS) has a better visual impact. Groundwater typologies are found to be much more rational and useful in developing management strategies, rather than simple listing as overexploited areas, critical areas, semi-critical areas, and safe areas as is commonly done. The typologies so delineated indicate on the map (or table) that balanced usable groundwater is in between 5 and 6 bcm/a as against the estimated balance of 20.5 bcm/a, and it is largely in poor hard rock type of aquifers, which occupy about a third of the area of the state.
在印度，根据地下水开发阶段和长期水位趋势，地下水评估单元被分为过度开采区、临界区、半临界区或安全区。直观地说，在安全区内，水井预计会正常运行并有良好的出水量。此外，在安全区内，新水井预计会成功。相反，在过度开采区，成功水井或高产量水井的期望要低得多。然而，当这些期望在现场无法得到满足时，人们会对评估的质量及其有用性产生怀疑，普通民众以及规划者、管理者和政治家会对评估地下水资源的机构产生完全的不信任。因此，需要以一种不会造成混淆的方式呈现结果。其中一种方法是使用地理信息系统（GIS）将评估结果与含水层特征相结合；这样做时，会出现一整套新的类别，可以进行映射。在本研究中，这些类别被称为地下水类型。每个类型都有一些共同的特征或特征，包括基本含水层特征和地下水开发阶段。因此，一个类别可能是安全的，但如果含水层较差，那么它就会与安全类别分开，而安全类别中的含水层较好，以此类推。在安得拉邦，该邦被选为这项研究的案例，共出现了八个主要类型，其中两个主要类型又进一步分为四个亚型。这种使用 GIS 理解地下水开采模式的新方法具有更好的视觉效果。与通常简单地将其列为过度开采区、临界区、半临界区和安全区相比，地下水类型在制定管理策略方面更合理、更有用。划定的类型在地图（或表格）上表明，平衡可用的地下水在 5 到 6 bcm/a 之间，而估计的平衡量为 20.5 bcm/a，这主要是在贫硬岩型含水层中，这些含水层占该邦面积的约三分之一。
