RESTORATION OF GILBERT HILL

Gilbert Hill is situated at Andheri (West) in Mumbai suburbans and contains a unique assemblage of spectacular vertical columns of black basalt rock of approx. 60m high. These columns usually have a hexagonal cross section and are believed to have developed by cooling of basaltic lava (which poured out from long fissures) near Mumbai, 65 million years ago. It is the only hill of its kind in India and was declared as a national park in 1952 by central government and was declared a grade II heritage structure by the Municipal Corporation of Greater Mumbai (MCGM) in 2007. Atop the rock column, the Gaodevi and Durgamata temples are also situated. A series of rockfall events were observed from the Gilbert hill affecting residential apartment complexes at the foothills. Adverse geological conditions and unscientific excavation for building construction seem to be the reasons for instability of hill-rock mass which lead to detachment of boulders from the slope surface. Considering the uniqueness of the hill, it’s heritage importance and risk to human life and property due to rockfall events, it was necessary to adopt rockfall mitigation measures on the hill slope.