Groundwater Potential Zone Identification Using GIS: Mettur, Salem District, Tamil Nadu

Abstract

Salem region is one of the drought inclined areas of Tamil Nadu. Being a rural zone, the area is finding a mitigation measure to keep the agribusiness on run. As a mitigation measure mapping the potential groundwater zones in the examination area will be a great alternate wellspring of water for the rural reason. The objective is to delineate the potential locations of groundwater zones using GIS software for the Metturtown panchayat, Salem district. The study area is inclined to drought. The different parameters that control the groundwater fluctuations, for example, geomorphology, contour, topography, LULC, soil; rainfall is broken down together as thematic maps. The slope map will be set up from DEM. These maps have been overlaid and the spatial analysis method, weighted overlay analysis using the GIS has been carried out. The ranking/weightage will be specified for every distinct bound of each thematic map. The weightages/rankings were relegated according to each thematic layer influence with respect to the Soil, LULC, and density of drainage, rainfall, and slope. The resultant maps display the groundwater potential zones ranging from very good to very poor zones.

1. Introduction

The Salem locale of Tamil Nadu is an agro-economic area is pronounced as a drought inclined zone among 20 other regions in Tamil Nadu. Despite what might be expected these locales additionally had seemingly contradictory weather conditions: Tamil Nadu and Karnataka got ordinary rainfall, about 46%, recorded insufficient rainfall. Each of the three states additionally experienced far-reaching surges in August 2018 six locales in Tamil Nadu. Other than having wellsprings of water, the locale is inclined to dry season henceforth the mitigation measure ought to be in a way that utilizes these wellsprings of water in the examination area. On that note finding the zones where there is a potential wellspring of groundwater will be an imperative mitigation measure for drought zone or to a greater degree an adapt up strategy. The objective of this research work is to identify the groundwater potential location using the GIS approach in the project area.

Finding the groundwater zones in the field will be a dreary process; GIS applications make it simple in delineating the zones remotely and additionally give spatial and transient information about the groundwater zones in the locale. Magesh et al. [1] utilized the GIS strategies to delineate the groundwater potential location in Theni. The MIF procedures helped in delineating the potential zones in terms of scales from (very poor to very good). Waikar et al. [2] stated that the multi-criteria analysis using the GIS applications for hydro-geomorphological mapping and resource evaluation for water resource management is an effective analysis. The study was carried out to evaluate the geomorphic features and drainage patterns in the Parbhani District recommend the GIS application has appropriate methods for groundwater potential zone. Mwega et al. [3] stated Groundwater is a naturally available resource that sustains basic needs, farming, and industrial purposes. The generated groundwater potential zone is arranged into scales from high to low. Ramu et al. [4]. Some of the features that control groundwater zone mapping are soil, drainage density, LULC, topography, rainfall, geomorphology, incline, and contour. Rajendran [5]. Drought mitigation measures ought to be propelled on a war footing and in a sustainable way. Groundwater recharging ought to get top need and any dry season mitigation plans should incorporate this key part. Owolabi et al. [6]. Validation of the potential location of groundwater has been carried out using the borehole yield for the Buffalo catchment, South Africa. The study area is prone to water supply deficiency; hence the mapping technique came in handy. Doke et al. [7]. GIS-based methods result with precise accuracy and computation time is less than the traditional field methods. Jhariya et al. [8]. Low slope pays the way for low runoff and high infiltration. It also results in good groundwater recharge. Melese et al. [9]. Drainage density is inversely proportional to the groundwater probability. Saranya et al. [10]. The groundwater mapping help in future planning of the artificial recharge zones in the Kanchipuram district. The resultant shows that moderate potential is available for the study area.

The present study incorporates the GIS applications in delineating the groundwater potential zone in the Mettur panchayat town panchayat, Salem district.

2. Study area

For the study purpose, Mettur town (11°45′ N and 77°45′ E) of Salem district has been chosen. It has a spread area of 410 sq. km at an elevation of 292 m (958 feet), situated at 52 km north-west of Salem. The Mettur town has a population of 52,813. Mettur is known for its huge dam built-in 1934, which is still one of the best dams in the country. It also attracts tourists from all over India. The dam opens in June every year for irrigation in the Kaveri Delta. The River Cauvery divides the town into two parts as it traverses in between the Mettur (Figure 1).

Figure 1.

Index map of the study area.

Among 16 rainfall stations, the most extreme of 1073.32 mm records at Tholuthur (edges of the basin) and 1016.31 mm records at Mettur station inside the basin. The demand for water has increased in the study area. Paddy, Sugarcane, Maize, Turmeric, and Cotton are the main agricultural crops. It has 27 income towns and 14 panchayats. The soil type is red in situ soil is commonly occurring type. The woodland soil in timberland areas, dark cotton soil occurs in the north-eastern part and sandy-loamy blended soil in south-western area. The aquifer system ranges between 2.5 and 28 m with yields ranging from 10 to 840 lpm. The bore wells recorded transmissivity esteems ranging from 1 to 250 m²/day.

3. Methods and materials

There are six imperative indicators to be specific, (i) geology, (ii) slope, (iii) geomorphology, (iv) land use/cover, (v) drainage and (vi) lineament for groundwater prospects. These parameters are most commonly used parameters in identifying the potential location. These parameters have a direct relation to the groundwater level. Preparation of maps for these themes (with the exception of slope) in view of picture attributes, for example, tone, surface, shape, shading and association are standardized. Slope is gotten from ASTER DEM 30 m resolution. Thematic maps of the examination area were readied. To get a wholistic perspective of the previously mentioned indicators, overlay analysis is required. Task of rank to an individual class depended on the influence of these themes as announced in literature. Rank and weight-based thematic layers have been unified through GIS in order to find out the resultant groundwater potential zones. Overlay analysis was done from the determined multi-thematic layers in a GIS domain.

3.1 Slope

Higher level of slope leads to fast runoff. The slope map was developed from the ASTERDEM and classified into five categories (Figure 2). Slope values ranged from 0 to 90 degrees, as the study area contained hilly terrain. Gentle slopes (0–18) were spread over the area in a maximum range. Slopes greater than 54.1 degrees to 90 degrees represent the hilly slope in the region. 36% of the study area is having a hilly slope of 54.1–90 degrees and 64% of the study area is having a gentle slope. The degree of slope is inversely proportional to the groundwater potential. The weightage was according from 1 to 5 based on the degree of slope in the region.

Figure 2.

Map showing slope in degrees of the study area.

3.2 Drainage

Drainage density is termed as the spacing distance of drainage (Figure 3). The ratio between the total length of the stream for each stream order. The drainage density (km/sq km) is categorized into five from 0 to 9100 sq/km. About 28% of the study area is having a drainage density of less than 840 km/sq km. The drainage density is inversely proportional to the porousness. The surface runoff will be more where the rainfall infiltration is less which happens in less porous soil. The weightage was decided accordingly with respect to the density/sq km ranging from 1 to 5.

Figure 3.

Map showing drainage density in km/km² of the study area.

3.3 Soil

The type of soil in the region reveals the groundwater recharge potential in the zone based on the soil properties such as permeability, conductivity etc., Based on these the weightage for the soil were given for sandy clay loam and loamy sand as 4, rock land as 1, sandy clay as 3, clay loam as 2 is shown in Figure 4. About 52% of the study area is of sandy loam followed by rocky land. The sandy loam soils have a high infiltration rate. More the infiltration rate, the more the groundwater potential.

Figure 4.

Map showing soil type in the study area.

3.4 Lineament

Lineaments are the surface manifestation of subsurface shortcoming or auxiliary relocation and deformations (Figure 5). The lineament density (km/sq km) varies from 0 to 1.4 km/sq km. It speaks to profound seated blames, breaks and joint sets, drainage lines and distinctive litho-contacts. It is a linear and curvilinear feature that is noteworthy for groundwater, mineral and metal explorations and exploitations. Lineaments were digitized after calculating the hill shade slope in the ASTERDEM data. Same as drainage density, lineament density’s weightage was given based on their densities.

Figure 5.

Map showing lineament density in the study area.

3.5 Geology

The geology type (Figure 6) in the study area has a more spread of crystalline rocks whose weightage was given as 1 based on its properties in conducting the groundwater recharge, followed by intrusive rocks having weightage same as prior. The semi consolidated sediments were given a weightage of 3 as it has moderate groundwater conducting properties.

Figure 6.

Map showing geology type in the study area.

3.6 Geomorphology

The characteristics such as texture, tone, shape, color etc., are used for delineating the Geomorphologic units (Figure 7). Structural hills are observed in the study area, which mostly acts as runoff zones due to their sloping topography. The pediplain was given a weightage of 3, followed by, structured hills (2), denudational hills (2), flood plain (2), waterbody mask (5).

Figure 7.

Map showing geomorphology in the study area.

3.7 Landuse land cover

Baseline information about occurrences of surface and groundwater can be directly or indirectly obtained using land-use/ landcover information of that particular area. The LULC effect (Figure 8) can be calibrated by means of reducing runoff and facilitating, or by trapping water on their leaf. The study area is categorized into six land-use patterns as water bodies (5), dense forest (3), degraded forest (3), barren land (2), fallow land (4), agricultural land (4) from the Landsat 8 data and corresponding weightage were given during the analysis.

Figure 8.

Map showing LULC in the study area.

3.8 Delineating the groundwater potential zone

The delineation of the groundwater potential zones has been created by means of integrating the thematic maps namely slope, drainage, soil, lithology, lineament, LULC, and rainfall using RS and GIS techniques. The interpreted layers were analyzed using weighted overlay method and resultant is the different potential zones (Figure 9). The south-west side of the study area is having a very good groundwater potential location compared to the north-east side. About 74.6% of the study area is having a moderate groundwater potential location, which can be utilized for artificial recharge of the wells and management plans.

Figure 9.

Map showing groundwater potential zones in the study area.

4. Conclusion

The groundwater potential zone map has been generated from the various thematic layers based on their significance and corresponding classes. In the present research work six conditioning parameters namely (i) geology, (ii) slope, (iii) geomorphology, (iv) land use/cover, (v) drainage and (vi) lineament were identified. These parameters were classified based on literature and expert opinion. The experts’ knowledge was important to determine the rank of each conditioning factor. The parameters like lineament density, geology, elevation, slope etc. determine the groundwater potential significantly.

The groundwater potential zone of the study area varies from very good to poor. Figure 8 shows the moderate level of potential zones is present in the study area due to various factors involved. About 74.6% of the total area falls under the.

“moderate” zone, 12.3% falls under “good” zone, 9.78% falls under “poor” zone, and 3.4% of the basin fall under “very good” zone. The results predict that if the groundwater potential zones were utilized properly for exploring the water resources, the drought can be coped up with potential agricultural practices.