3.3 Monsoon Surface
The projects in this section revolve around the highest of three reservoirs in the hills of North Mumbai: Tulsi. This water body, the overflow of which is the Dahisar that exits through Manori Creek, is proposed as a hub in a collection and distribution network that takes advantage of variations in both, the rainfall across the hills of Salsette and the sea levels around them. The primary operator here is the ‘contour trench’ not unlike the short one built in the nineteenth century to extend the watershed of Tulsi beyond its valley. The trench facilitates a networking, particularly on days like 26 July 2005 when monsoon waters and sea levels defy averaging across time and space. At times like this it becomes necessary to work with a source that is an entire surface and with multiple destinations that are all around – Vasai to the north, Manori and Versova to the west, Mahim/Mithi to the south and Thane to the east.
Trenches, however, are more than facilitators of a flexible and agile dispersal of dangerous waters that accommodate the extreme possibilities and everyday uncertainties of the monsoon. They also collect runoff from surfaces within and beyond the current catchment of Tulsi and Vehar, runoff that they can carry into these reservoirs or feed into decentralised tanks in settlements east and west of the Sanjay Gandhi National Park. Here, trenches, while protecting neighbourhoods from excessive runoff, offer neighbourhoods the opportunity to re-engage a monsoon surface. The Dahisar, Poinsar, Oshiwara and the many other nullahs on both sides of the park, rather than being mere drains, can each be made surfaces of holdings with the possibilities of treating, cultivating and other activities that carry more of the Park into the city than just water.
Importantly, though, trenches on the outer slopes of the north-south ranges of the Park can serve as thresholds between forest and city. The two are divided today by boundaries and violations that are leading to fences. It is a sad loss of a rare opportunity. While monsoon water is their major concern for which they are prepared each year, trenches can be for much of the year places of culture, rock-cut architecture and activity in themselves, places that benefit from the adjacency to a forest with a rich wild life, trails, climbs, and of course, the Kanheri caves. Here, openness and community form a ‘boundary’ between city and park that recalls the spirit of the maidan while the temporal workings of the trench recall the richness and complexity of the valley of the ancient ‘City of Kanheri’ to the northwest of Tulsi, which a traveller in the 1600s likened to an ‘aqueduct’: a complex of cisterns and conduits that construct one large amorphous surface that spreads and gathers monsoon waters, blurring the divide between ridge and valley, surface and depth, flow and overflow.