(This story originally appeared in on Apr 18, 2017)

How to build a beach

Marine Drive and Ma him Bay are in for a sea change over the next four years, with the state maritime authority intending to burn up more than Rs 400 crore to lay out a beach each a kilometre long at the two popular seafronts.The Maharashtra Maritime Board , enlivened by its success in creating an artificial beach in the neighbouring Ratnagiri district, wants to replicate the experiment at two stretches of the city's coastline which is currently anchored with tetrapods.An artificial beach will not only prove to be a more sustainable and picturesque way of reclaiming land than the four-legged boulders, it will also provide Mumbaikars, who get less than a square metre per capita open space, with more of it.Ratnagiri's Mirye beach, which cost the state around Rs 50 crore, was laid over three seasons, from October to this April, by the maritime engineers. First, an artificial reef was created 500 metres above the seabed with geobags, which are special sand-filled sacks made of a high-strength canvas called geofabric. Then, nearly1.25 lakh cubic metre of sand was laid atop these to create a beach that is 750 metres long and 50 metres wide.The creation, more nuanced than a simple sand dump as it involves calculations of tidal motion and depth measurement, will now be attempted at Dadar Chowpatty (part of Mahim Bay) and near Girgaum Chowpatty It comes with its own challenges.The land strip off the sea at Dadar has eroded at the hands of an overpop ulated city hemmed in by the sea. To replenish the land, around 10 lakh cubic metre of sand will be needed to create a beach spread out over 1000x100 square metre. And the sand for such a project in Mumbai will have to be transported by sea, on barges, which is likely to protract the time and cost of the project, said Maharashtra Maritime Board deputy director Jitendra Raisinghani . The sand will replace the rocks and tetrapods that have been dumped here to declare a coastline, unclogging public access to the sea. The experiment is likely to come attached with a Rs 170-crore price tag.Similarly, the Maharashtra Maritime Board will need to procure around 15 lakh cubic metre of sand to extend Girgaum Chowpatty up to Marine Drive Flyover, to provide a beach that will be a kilometre long and 200 metre wide. The outlay is pegged at Rs 240 crore.Will the beaches last the Mumbai rains? “The coming monsoon will be the test of how successful our Mirye experiment has been,“ said Raisinghani.The projects, slated to kick off in the fiscal 2018­19, will be partly funded by the Asian Development Bank.Raisinghani said the work will begin after the requisite permissions has been obtained. After the work begins it will take another five-odd seasons -or three years on the outside -to complete the project, he said. No work can be done during monsoon.Architect and town planner PK Das, who is pursuing the cause of land reclamation at Dadar-Prabhadevi Chowpatty with the state government for the last12 years, showed optimism about the move but advised caution. “Before embarking on such a complicated project, the Maharashtra Maritime Board will need to take many precautions. It will have to get studies done -like a bathymetry survey, tidal wave pattern modelling, and study of the deep sea -from a reputed consultant. The project doesn't merely involve emptying sandbags on a spot,“ Das said.The Board will also have to factor in the cost of replenishing sand every three to four years, otherwise “we will be back to square one a few years down the line“, Das said.