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  • Writer's pictureFergus Telfer

D&T #03 – "Wading through the case studies"


In this blog post I aim to discuss the research I have done into how the world’s water crisis is already affecting cities in water stressed regions. These case studies outline that an International Water Crisis is not a distant prediction but a problem facing millions right now. We need to learn from these examples to curve water trends and attitudes to water in large cities in order to avoid similar problems in years to come. Which cities are already facing a water crisis? And, how are they reacting?


Flooding in water-stressed Mexico City, published by the BBC

About one fifth of Mexico’s population live in Mexico City. It’s population is expected to rise to 30 million in the next ten years. One of the challenges this growing city is experiencing is how to manage its water resources because, currently, its infrastructure is literally falling apart. Ironically, the city’s site was originally chosen due to its access to water. The settlement and a network of canals were built by Aztecs in the middle of Lake Texcoco to store seasonal floods as freshwater year round. During the 1500s the Spanish conquered Tenochtitlan and began draining the lake. This continued as the city expanded over the lake’s bed, now barely any trace of it remains.


Mexico City, published by Quartz

The city has had to turn to other sources, in this case it’s a local aquifer. Accessing groundwater reserves was discussed in an earlier post. We have become much better at finding and exploiting them, which is fine to supplement water shortages rarely. However, Mexico City had become heavily reliant on aquifers; Arnoldo Matus Kramer, the city’s Chief Resilience Officer, said;

“We are exploiting our local aquifers at a very high rate… we haven’t invested enough resources to have a robust monitoring system. So there’s a lot of uncertainty how the local aquifers work”

The local aquifer supplies half of Mexico City’s freshwater and it could be empty within 30 to 50 years, according to Kramer’s team [BBC]. Another 30% of the city’s water is piped in from rural areas of Mexico hundreds of miles away [NPR]. Draining the groundwater from beneath the city has indivertibly caused another problem, the streets are sinking. As groundwater is pumped out “over twice as fast as it can be replenished” [Quartz] the water table drops. In some places the city is sinking by up to 15 inches per year [Science.gov]. This dramatic sinking is due, in part, to the perfect storm of geology that the city is built on. The clay and lava rock crust is susceptible to collapsing as it shrinks which is highly dangerous in more deprived areas of the city with higher population densities.

Sinkhole in Mexico City (2017), published by Quartz

The irony only continues caused by more bad decisions as Mexico City has sprawled across the drained marshes. Concrete paving within the depression of the dry lakebed unfortunately encourages flooding in the rainy season. That’s right, a water stressed city prone to flooding. One solution that’s been proposed has been to tear up some of this paving. Pedregal, an area southwest of the city centre, is actually built beyond the lakebed on porous, hardened lava flow. Pedro Camarena, a landscape architect at Mexico’s National Autonomous University, has suggested removing the impermeable paving, water could be sucked down to the replenish the aquifers below. His research has led him to suggest that the local Government encourages people to remove top soil and expose the rock in ‘lava gardens’. These images show the development in Pedregal that has led to paving over the porous lava rock below [Quartz]:



Other solutions have been suggested by politicians; home rain catchment systems, replanting forests and improving the management of agricultural water. Water management is a hot topic in Mexico, remember the capital pipes in 30% of its water, that’s all coming from rural areas. In many situations like this, the first to suffer are the powerless and in this case, that’s Mexico’s farmers. This month voters in the Mexican border city, Mexicali, have rejected a new $1.4bn brewery [Guardian]. Beer making has been a major export of Mexico but it is also a water intensive process. In 2016, Mayor Leoncio Martínez Sánchez of the municipality of Zaragoza complained [Guardian]:

“We’re worried because we’re already being impacted by this extraction of 1,200 litres of water per second (by the brewery) … it’s contradictory that while Constellation Brands has industrial amounts of water to make beer, the municipality of Zaragoza doesn’t have 100 litres (per second of water) of water to give people to drink or use in their homes”

The Government is juggling encouraging economic growth with water to its citizens’ and is losing. Human impacts are creeping into the capital too. During the dry season water trucks, or ‘pipas’, deliver water to residents in the eastern stretches of the city where taps are shut off first. However, the water quality is reported to be “disgusting” [NPR] and some resident are forced to pool their money to purchase privatised pipas.


'Pipas', published by Quartz

Privatising water is a scary prospect- literally a Bond villain’s plot. In Quantum of Solace (2008) Dominic Greene, a rich businessman, attempts to take control of Bolivia’s water supply for profit. Much of the movie was actually filmed in Mexico.



A final solution for Mexico City, perhaps the most worthwhile one, upgrading its existing infrastructure. Kramer’s team estimates that 40% of the city’s water supply is lost due to leaking pipes [BBC]. This figure represents an enormous problem facing Mexico’s Government and is consistent across several sources. One such step taken already was the construction of a 62km pipe, 200m deep to ease the current drainage system. This replacement will improve the city’s ability to control drainage.

Mexico City's new drainage tunnel, published by the BBC

Another city which is already struggling with water management is Cape Town, South Africa. Cape Town has been the face of the Water Crisis when, in January 2016, officials announced that the city had 90 days before all mains water would have to shut off. This news rocked the World, how could a city of four million people run out water? Never before had such a severe drought hit Cape Town for three years in a row. The drought devasted the water supplies - six dams supply 99.6% of water to the Western Cape [City of Cape Town]. This is Theewatersloof Dam near Cape Town in January 2018:

Theewaterskloof Dam January 2018, published by CityLab

There have been allegations of mismanagement in the region as 40% of this water was allocated to agriculture throughout droughts with no attempt to reduce agriculture uses [The Conversation]. These allegations go so far as to claim corruption within the Department of Water and Sanitation and the crisis could’ve been avoid if a budget for drought relief had been allocated but by January 2018 it was too late. ‘Day Zero’ (April 12th) came and went, the city managed to dramatically cut their water usage in half from 1.2 billion litres per day in February 2015 to 511 million in March 2018 [GroundUp]. This is relevant news for this project because it shows it can be done; individuals sacrificing luxuries can make a real difference. It truly remarkable to encourage such a large city to do more than just turn off the tap whilst you brush your teeth. However, water inequalities in Cape Town run deeper and into murkier waters the closer you look. According to the documentary ‘Day Zero: how Cape Town stopped the taps running dry’ [Guardian] 25% of Cape Town’s population live in townships and use only 4% of the total city’s water. But as of March 2018, 64% of the 250,000 water management installed in homes in “indigent areas” [GroundUp]. More affluent areas were scared into not watering their lawns at the prospect of having to go and collect water from communal taps, a reality facing much of the city on a daily basis. Perhaps this scathing review is unwarranted but the reality is that poorer areas had been dealing with water scarcity for decades and now sharing their water saving techniques to wealthier areas of the city could save those areas. Habitats were changed; showers were cut to two minutes of running water per person, washing clothes was done by hand, all grey water was saved to flush the toilet, rainwater was saved for watering plants and lawns were re-laid with artificial grass. The Government also reduced water pressures, approximately a 10% overall saving [CityLab]. Water usage maps were posted pitting neighbourhoods against each other to use the least amount of water. For longevity, Cape Town has since looked to invest in desalination projects but uncertainty remains. They have since indefinitely pushed back Day-Zero, it helped the rains came just in time.


Cape Town locals queuing for a natural spring, published by CityLab

Other cities have pre-empted water scarcity issues and have identified one key way to reduce peoples usage; treat it as a commodity. In 2017, Philadelphia decided to link water bills to household income [CircleOfBlue]. This is believed to be a fairer way to charge for a necessity of life that also must be valued to prevent overuse. In Sydney, water prices have been rising. In 2019 Sydney Water proposed to raise bills again and asked the Independent Pricing Tribunal to increase their spending by 20% to $11.4bn on new infrastructure in response to droughts lowering dam reserve levels [Sydney Morning Herald]. Water stresses will also become a problem closer to home; London could face a water crisis according to the BBC. Between 2015 to 2019, over 26,000 pipes burst in the capital [BBC]. This combined with the population continuing to grow and green space being reduced makes the city more susceptible to droughts, flooding and water mismanagement; as we’ve seen in Mexico and South Africa.

Another burst pipe in London, published by the BBC

These case studies have shown that resolving water stress within cities will require a combination of individual altering their habit and legislation changes from Governments. Solutions circle back to the value that we place on water but it’s the cities that identify problems early that will give themselves the best opportunity to adapt in time. I want to continue to investigate other solutions and how technology can be used in this crisis to improve our water usage and answer the question; does product design engineering have a role to play in saving our water?



Sources:

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