Identification of fresh groundwater areas in the Central Godavari Delta region, Andhra Pradesh, India – an integrated approach

Groundwater is vital and dependable source of water for drinking, agriculture and industries. The Central Godavari Delta of East Godavari district, Andhra Pradesh, is composed of alluvium wherein fresh and saline pockets exist together in close proximity. The present study is to identify freshwater pockets using geomorphological, land-use/land-cover, geophysical and geochemical analysis. Groundwater samples are analysed for electrical conductivity which revealed that about 35% of area is occupied by freshwater pockets in the north western and eastern parts. Vertical electrical sounding data inferred that resistivities less than 5 ohm-m is clay/sand with saline water; 5–10 ohm-m sandy clay and 10–75 ohm-m corresponds to freshwater zone. Freshwater pockets at depths greater than 8 m observed in northern part and shallower depths in southern parts. This integrated study proved successful in identification of fresh groundwater pockets in the delta region.