What is drastic method?
DRASTIC method is one type. of overlay & index method for vulnerability assessment. This paper represents a. comprehensive review of available literature on the applications of Geographic. Information System (GIS)-based DRASTIC method for groundwater vulnerabil-
What makes an aquifer vulnerable?
Aquifers are areas of soil or rock under the ground where cracks and spaces allow water to pool. They are considered highly vulnerable based on factors such as how deep it is underground, what sort of soil or rock is covering it, and the characteristics of the soil or rock surrounding it.
What is drastic index?
A high DRASTIC index corresponds to the high vulnerability of the aquifer to pollution. In the DRASTIC index, each parameter is rated on a scale from 1 to 10 that shows the relative contamination potential of that parameter for that area.
What is the difference in between drastic and Drastil for calculating groundwater pollution potential?
DRIST and Modified DRASTIC DRIST considers only parameters related to the unsaturated aquifer zone, while DRASTIC works with the aquifer saturated zone characteristics . The calculation of the DRIST vulnerability index is similar to that for DRASTIC (but ignoring A and C parameters).
What affects vulnerability groundwater?
In general, the vulnerability of the water from public-supply wells to contamination depends on contaminant input in the area that contributes water to a well, the mobility and persistence of a contaminant once released to the groundwater, and the ease of groundwater and contaminant movement from the point of recharge …
What is water based vulnerability?
For the purposes of this report, ground water vulnerability to contamination is defined as: The tendency or likelihood for contaminants to reach a specified position in the ground water system after introduction at some location above the uppermost aquifer.
Which type of aquifers are more susceptible to contamination?
Unconfined sand and gravel aquifers
Unconfined sand and gravel aquifers are more vulnerable to contamination.
What is groundwater vulnerability mapping?
It is designed to calculate vulnerability scores (numerical values) for different locations by combining seven thematic layers/factors, i.e., Depth to Water, Net Recharge, Aquifer Media, Soil Media, Topography (Slope), Impact of Vadose Zone, and Hydraulic Conductivity of the Aquifer.
What does high water vulnerability mean?
Extreme water vulnerability: Extreme water vulnerability is the combination of the highest levels of physical water scarcity and lowest levels of drinking water service that affects a given population (surface water, unimproved or limited water service).
What is water quality guidelines?
dd) “Water Quality Guidelines (WQG)” refer to the level for a water constituent or numerical values of physical, chemical, biological, and bacteriological or radiological parameters which are used to classify water resources and their use, which do not result in significant health risk.