Aspects of Rural Supply, and Source Using RS & GIS: A Case... 425 SUSTAINABLE ASPECTS OF RURAL WATER SUPPLY, QUALITY AND SANITATION SOURCE USING RS & GIS: A CASE STUDY

Access to safe drinking water remains an urgent necessity in the world as it is directly related to health. Groundwater accounts for more than 80 per cent of the rural domestic water supply in India (World Bank 2010). The main aim and objective of present research study is on applicability of satellite remote sensing techniques for sustainability of rural water supply sources of Medchal mandal in Ranga Reddy district. The integrated groundwater prospects maps are prepared by using different thematic layers like Geology, Geomorphology, Structures (Lineaments), Hydrology, etc. Drinking water quality data of rural water supply sources situated in Medchal mandal are studied for the parameters like Fluoride, Total Dissolved Solids, Total Hardness, Alkalinity, pH & Chloride to assess the spatial distribution of groundwater quality in terms of potable or non-potable. Satellite Remote Sensing and GIS studies are employed by making use of other collateral data, Well Inventory data and Rural Water Supply data are incorporated. Groundwater quality data acquired are spatially interpolated using Inverse Distance Weightage (IDW) method to demarcate the spatial (locational) variations. Water demand is calculated for present (2012) and designed period of 20 years (2032). After detailed well inventory combined with integrated groundwater prospects and quality studies, the problematic habitations are found out and plan of action and remedial measures have been proposed. The plan includes proposing water harvesting structures to either dilute the areas where the water quality problem is there or to increase the groundwater reserves through artificial recharge in areas where there is sustainability problem.


Introduction
Due to various natural and anthropogenic activities, the ground and surface water resources substantially stand prone for pollution. Medium resolution satellite images are increasingly used in groundwater exploration because of their utility in identifying various ground features, which may serve as direct indicators of presence of groundwater (Ramamoorthy P, 2011). The groundwater is the only source available for the study area. For the study area, the water demand for 20 years of each habitation is calculated and compared with the existing water demand. If the existing demand is not sufficient to meet the requirement, additional sources and its suitable

Climate and Rainfall
The climate of the area is classified as "Tropical Rainy" , the minimum daily temperature is 16° C and maximum is 43° C. The normal annual rainfall for the mandal is 820 mm.

Data Used
The following of data are used in the study area: Topographical map of Survey of India (SoI) on 1:50,000 scale.
The geographic coordinates of all the water supply sources and overhead / ground level reservoirs, etc., are collected during well inventory.

Methodology
The following is the brief methodology adopted in the study area:

1.
The present population is projected up to 20 years to calculate the water demand and plan of action for future. The methodology followed is shown below in the form of a flow chart ( Figure 2):

Thematic Maps
The following are the different thematic maps prepared as part of project:

Villages, Population and Drinking Water
Demand: The total number of Gram Panchayats        Figure 10.

Figure10: Locations of Quality Tested Groundwater Samples
The spatial distribution of different chemical elements in the study area is carried out by making use of Inverse Distance Weightage (IDW) interpolation technique. It is observed that the quality is within the permissible limits for Total Dissolved Solids, Total Hardness, Chloride, pH and Alkalinity. But the fluoride is marginally affected.

Fluoride:
The distribution of fluoride map is given in Figure 11. It is observed that the southern area of the study area is fluoride affected marginally. A small area to the north and central areas is also showing more than permissible limits in fluoride.

Results and Discussion
By taking into consideration geology, geomorphology, groundwater quality, structural aspects and well Inventory data, the final action plan for Sustainability of Rural Water Supply schemes is prepared and shown in Figure12.

Figure12: Final Action Plan Map of the Study Area
Journal of Rural Development, Vol.37, No. (2), April-June:2018 In the final map the following aspects are shown:

Conclusion
By assessing the overexploitation, drinking water demand versus supply and quality problem and to plan suitably, the following remedial measures are proposed long-term and short-term to maintain the sustainability of drinking water sources:

Short-term Remedial Measures
The fluoride distribution reveals that the southern area of the study area around

Long-term Remedial Measures
As there is tremendous demand of groundwater for agriculture / industrial purposes, for which the area is falling in overexploited zone and lots of money is spent every year on drilling of new borewells, especially in Medchal village, it is recommended to adopt surface-based water supply -as distance source (River-based) scheme.
Thus, Remote Sensing & GIS are effective tools in preparation of a plan of action on improving sustainability of RWS sources for providing safe drinking water.