Chilika lake is the largest lagoon along the east coast of Indian state Odisha, situated between latitude 19° 28′ and 19° 54′ N and longitude 85° 05′ and 85° 38′ E. The place is known for rich biodiversity and is the largest wintering ground of migratory bird and largest population of Irrawaddy dolphin, habited by migratory birds and by a special type of dolphins. The highly productive ecosystem of the lake supports the livelihood for fishermen and also acts as drainage for Mahanadi River Basin. The estuary is very sensitive to the sediment dynamics. The closure of estuary mouth or shifting of Chilika Lake mouths tremendously changes salinity and ecology of the lake system. The east coast of India along this coast is having a net alongshore drift of about 0.7 × 106 m3 annually toward north direction. The inlets of Chilika Lake are under the influence of alongshore sediment transport from the coast. Apart from this, the rivers bring sediments during peak southwest monsoon season. Because of this the inlets are migrating, depending on the season. The details of migration of estuary opening were analyzed using satellite imageries. The analyses of watershed, coastal process, and configuration of estuary are detailed in this paper. © Springer Nature Singapore Pte Ltd. 2019.