Like so many cities all over the world, Mumbai is facing a water crisis. In fact, according to BBC News, it is experiencing “one of the worst water shortages in its history.”
Mumbai receives most of its water from lakes that are heavily dependent on monsoon rainfall. Rainfall figures this year, however, are “alarming” as “one lake has enough water to last for the next three weeks, while two others have reserves for about two months.”
In response, authorities have reduced the amount of water going to the city and asked people to conserve the supply that they do get. They are also considering cloud seeding, we read.
Other options for Mumbai are explored by Robyn Perkins in emergeMUMBAI. Last year, this project was one of the winners of 2008 ASLA Student Awards. Quoting the project statement:
emergeMUMBAI addresses flooding at a regional level, water management and public social spaces for housing redevelopment sites, and most importantly, it alleviates the insufficient water supply for the individual citizen. The project uses modern techniques combined with Indian models to provide solutions that work within Mumbai’s culture and maintenance/implementation regimes. Each block of the colony becomes self-contained in terms of water management, while supplying enough water to meet its consumption demands.
The full description, which we will not attempt to summarize here, can be found on the ASLA website. But here are some diagrams of proposed hydrological flows.
“emergeMUMBAI started by creating the first ever map of flood points in greater Mumbai,” writes Perkins. “This investigation of where and why the flooding occurs led to regional solutions the city could use. This analysis determined the location of high-risk sites, including government housing sites possibly up for redevelopment. The investigation continued by focusing on one critical, 100-acre site.”
At that site, rainwater is directed to a collection tank system under the courtyard. The water gets filtered and its sediment load allowed to settle.
When needed, “a play pump brings water to ground level where it flows through the slow-sand-dobi-ghat filtration tank. The end result here is grey water, but is clean enough for laundry and bathing.” And perhaps enough to alleviate Mumbai's water shortage.
Rainwater Harvesting in Quito
Rainwater Harvesting in Al-Andalus