134
S. Santra and S. Biswas
2 Study Area
The study area mainly follows the river Subarnarekha, a major river on the western
part of Purulia district. Subarnarekha flows through two blocks of Purulia district,
Jhalda-I and Baghmundi. In the present study, three adjacent blocks, Jhalda-II,
Joypur, and Balarampur are also taken, as these blocks also have groundwater scarcity
[1]. The areal extent of the study area is 1549.13 km
2 lying between 23º North to
23º36” North in latitude and 85º48’36” East to 86º19’12” East in longitude.
Subarnarekha is known for its flash floods during the monsoon season. But with
contrast, it is also the river basin having the lowest groundwater potential with a
groundwater potential of 1.82 bcm (lowest among all the rivers of India) [20]. Average
rainfall in the area remains minimal throughout the year except during the monsoon
period. Residents of the area, therefore, depend mostly on the available groundwater
for their daily needs as well as irrigation. As a natural outcome, groundwater is being
depleted very fast [21, 22]. In the past few years, irregularity of rainfall joined the
fleet, and the area is going through a severe groundwater crisis [23].
3 Methodology
Some physical methods like groundwater depth, bore well data, soil type, slope, local
status, availability of land, presence of harmful metals and chemicals nearby, presence
of industry, and presence of harmful organic substances are used for selection of
appropriate recharge site in localized studies. But to select those recharge sites on
a large scale, the analysis may be done using GIS. Among the different aspects of
using GIS, the basic difference is in the selection of layer used and method adopted
to obtain the final output.
In the present study, soil type, drainage density, lineament density, geology,
geomorphology, land-use type, and rainfall data are used as layers, and analytic
hierarchical process (AHP) [24] is used to calculate the weight of each of the individual layers as the input of the hierarchical fuzzy logic. Finally, hierarchical fuzzy
logic is used through a total of seven steps to finding the output layer.
The district block boundary map of Purulia is collected from [24] at a scale of
1:2,50,000. From this map, an area has been extracted, taking five blocks (Fig. 1).
3.1 Analysis of Digital Elevation Model
3.1.1 Digital Elevation Model
Digital elevation model (DEM) is a 3D representation of a terrain’s surface created
from terrain elevation data. From satellite data, latitude and longitude of the
S. Santra and S. Biswas
2 Study Area
The study area mainly follows the river Subarnarekha, a major river on the western
part of Purulia district. Subarnarekha flows through two blocks of Purulia district,
Jhalda-I and Baghmundi. In the present study, three adjacent blocks, Jhalda-II,
Joypur, and Balarampur are also taken, as these blocks also have groundwater scarcity
[1]. The areal extent of the study area is 1549.13 km
2 lying between 23º North to
23º36” North in latitude and 85º48’36” East to 86º19’12” East in longitude.
Subarnarekha is known for its flash floods during the monsoon season. But with
contrast, it is also the river basin having the lowest groundwater potential with a
groundwater potential of 1.82 bcm (lowest among all the rivers of India) [20]. Average
rainfall in the area remains minimal throughout the year except during the monsoon
period. Residents of the area, therefore, depend mostly on the available groundwater
for their daily needs as well as irrigation. As a natural outcome, groundwater is being
depleted very fast [21, 22]. In the past few years, irregularity of rainfall joined the
fleet, and the area is going through a severe groundwater crisis [23].
3 Methodology
Some physical methods like groundwater depth, bore well data, soil type, slope, local
status, availability of land, presence of harmful metals and chemicals nearby, presence
of industry, and presence of harmful organic substances are used for selection of
appropriate recharge site in localized studies. But to select those recharge sites on
a large scale, the analysis may be done using GIS. Among the different aspects of
using GIS, the basic difference is in the selection of layer used and method adopted
to obtain the final output.
In the present study, soil type, drainage density, lineament density, geology,
geomorphology, land-use type, and rainfall data are used as layers, and analytic
hierarchical process (AHP) [24] is used to calculate the weight of each of the individual layers as the input of the hierarchical fuzzy logic. Finally, hierarchical fuzzy
logic is used through a total of seven steps to finding the output layer.
The district block boundary map of Purulia is collected from [24] at a scale of
1:2,50,000. From this map, an area has been extracted, taking five blocks (Fig. 1).
3.1 Analysis of Digital Elevation Model
3.1.1 Digital Elevation Model
Digital elevation model (DEM) is a 3D representation of a terrain’s surface created
from terrain elevation data. From satellite data, latitude and longitude of the