© 2019 JETIR March 2019, Volume 6, Issue 3 www.jetir.org (ISSN-2349-5162) SITE SELECTION FOR SUB SURFACE DAMS ACROSS PAPAGNI RIVER IN CHAKRAYAPETA MANDAL USING GEOSPATIAL TECHNOLOGIES 1Dr T. Siva Prathap, 2 Dr Mohd Akhter Ali, 3 Anupreet Singh Tiwana, 4 M. Kamraju, 5 Sagar M Waghmare 1,2,3,5 Assistant Professor, 4 Research Scholar 1 Department of Earth Sciences 2,3,4 Department of Geography 1Yogi Vemana University, 2 Osmania University 3 Mata Gujri College (Autonomous) 4Centre for Economic and Social Studies 5S.G.Balekundri College of Engineering, India ABSTRACT A subsurface dam (SSD) is built across streams or valleys to establish an underground reservoir and to recharge groundwater. A subsurface dam constructed below ground level to arrest the flow in a natural aquifer. The best sites for construction of SSD are those where the soil consists of sand and gravel with rock and an impermeable layer at a few meters depth. Ideally the SSD should be built in the areas where rain water from a large catchment area flows through a narrow passage. The most favorable zone for construction of SSD is an area with gentle slope between hills and plains. The underground reservoirs in sand rivers are principally recharged by rainwater from flash floods, which originate in catchment areas with higher elevation. Upon full saturation of the underground reservoir the remaining flash floods will pass over the dam without further infiltration to replenish the aquifers down streams. The subsurface dams are more advantageous in dry regions because they offer minimal evaporation, as the evaporation is confined to the upper layers of the SSD. They avoid the problem of submergence of land area, and allow negligible water contamination. They also form sound basis for water budget available in the regions of low rainfall particularly rain fed regions of Rayalaseema region in general and YSR Kadapa district in particular. In the present study Chakrayapeta mandal is taken as the area of interest for the identification of suitable sites of SSDs using the available Digital Elevation Models from the Bhuvan Geoportal services and application of Geospatial Technology for their advantages, accuracy and time management. Keywords: Subsurface dam, Geospatial Technology, Digital Elevation Model, Chakrayapeta INTRODUCTION Natural groundwater storage can be improved by constructing a subsurface barrier that is a subsurface dam, in order to capture the subsurface flows and raise the groundwater levels (GWLs) in the sediment layers. JETIR1903812 Journal of Emerging Technologies and Innovative Research (JETIR) www.jetir.org 82 © 2019 JETIR March 2019, Volume 6, Issue 3 www.jetir.org (ISSN-2349-5162) Subsurface dams are preferable to surface dams because of lower evaporation, higher functionality, lower cost of construction, lessened risk for contamination and the possibility of utilizing land over the dam. Therefore subsurface dams constitute an affordable and effective method for the sustainable development and management of groundwater resources. Subsurface dams are the essentials in the India to overcome various problems related to water crisis in the arid and semi-arid areas. Subsurface dams have mainly advantages like water storage system without land submergence, Prevention of evaporation of reserved water, Clean, safe water, Utilization of renewable resources (Ishida et al., Borst and de Haas, Hoogmoed , Şen and Khairy et al.). Over the centuries population explosion, urbanization, conversion of forests to agriculture, have multiplied the demand for water. Fresh water problem is not limited to the arid climatic regions, even in areas with good supply the access to safe water is becoming a critical problem. For many the main source of water is the surface water that flows in streams, rivers and ground water. Rain water is the main source for recharge of Groundwater. The recharge depends on intensity of rainfall distribution, soil type and slope of the basin, land use and evaporability of the area. Infiltration takes place in inverse proportion to the intensity of the rainfall, slope and direct proportion of the porosity and vegetation cover. The infiltrated water percolates down after meeting Evapo-transpiration demand of vegetation from root zone and will be around 5-20%. On an average, the recharge from rainfall may work out to about 10% for the entire state of Andhra Pradesh. The extraction of ground water has to be limited to long term average annual recharge to use ground water on renewable basis (AP State Ground Water Department Report). The rainfall in India is not uniformly distributed in time and space, which is causing the need for regulation and management of waters by resorting to structures creating storages. The rainfall occurs mainly during monsoon period of 4 months. The rainy days are normally about 60 days during the above period. This pattern of rainfall results in flashy flood, which continue only for few days. The seasonal flow available in the streams and rivers is generally groundwater contribution, especially in south India since south India doesn’t get any contribution from snowmelt. The runoff from floods is much more than the seasonal flow in the stream. Since the flashy flow is irregular, it requires a measure to utilize regulating the same. To achieve this objective it is required to have a structure across the stream or river which creates a reservoir. The main objective of storage reservoir is to store the flood flows and regulate the supply by means of distributive system over a long period. The flows available in the streams or rivers can be tapped by means of either pumping schemes or anicut schemes, which do not cause any storage. For tapping seasonal flows, it is required to have storage structure across the stream or river since the flows are regulated. One such feature similar to the natural dykes acting as artificial bund causing underground reservoir is Sub Surface Dam. The concept of artificial Sub Surface Dam and artificial sub surface reservoir is introduced in recent times in India. The literature available on Sub Surface Dams is also very limited. A sub-surface dam is a vertical, impermeable barrier through a cross section of a sand- filled, seasonal river bed. A ditch is dug at right angles across the stream and into each bank, preferably where a rock dyke protrudes. This provides a solid, JETIR1903812 Journal of Emerging Technologies and Innovative Research (JETIR) www.jetir.org 83 © 2019 JETIR March 2019, Volume 6, Issue 3 www.jetir.org (ISSN-2349-5162) impermeable base onto which a simple barrier / masonry wall can be built within the trench. The main objective of the structure is to stop the subsurface flow from the given section of groundwater basin. OBJECTIVES The main objective of the present work is to understand the To identify suitable sites for Sub Surface Dams using Geospatial Technologies. To manage rain water. REVIEW OF LITERATURE Vasanthakumaran et al., (2002) used remote sensing and GIS techniques for selecting suitable sites for artificial groundwater recharge in the rocky terrain of Southern India. Thematic maps of soil, lineament, and drainage density were prepared using toposheets and satellite data. ArcView and ArcInfo GIS softwares were used to integrate these developed themes after assigning appropriate weights to each theme, which resulted in the identification of suitable artificial recharge sites. Chenini et al., (2010) used the GIS based multi-criteria analysis technique to map groundwater recharge zone in the Maknassy basin (central Tunisia) where depletion of groundwater levels were taking place for the last decade and the problem further aggravated due to increased demand for agricultural and industrial needs and arid climatic conditions. Thematic maps of the factors (watershed limit, drainage, drainage density, lithology, fractured outcrops, lineament, permeability, and piezometry) influencing the groundwater recharge were prepared and integrated in GIS after assignment of weights. The resultant map was categorized as per the weight ranges obtained. Sukumar and Sankar (2010) delineated the potential zones for artificial recharge using GIS in Theni district, Tamil Nadu. Three problems, deeper groundwater levels, over-exploitation and salinity related to groundwater were identified in the study area. Therefore the layers of permeability, soil depth, drainage intensity, water holding capacity, soil texture and geology were integrated in GIS environment to prioritize the area for the identification of suitable artificial recharge sites. Structures like check dam and percolation ponds were suggested to create new plans and models to implement the water resource development and action plan in the study area. Sharma and Kujur (2012) applied remote sensing and GIS techniques for the identification of suitable sites for artificial recharge structures in and around Gola block, Jharkhand. Thematic data pertaining to geology, geomorphology, land use/land cover, lineaments, drainage pattern, etc. were prepared by visual interpretation of the digitally enhanced satellite data IRS-P6 LISS-III, for study area of Gola block, Ramgargh district, Jharkhand, India. The study found that in a hard rock terrain intersection zone of lineaments provide potential for groundwater accumulation and recharge. The multi-layer integration viz. geomorphology, land use, geology, lineament density and drainage density data helped to identify suitable zones for artificial recharge. These zones were then compared with