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3 Things Cities Can Learn from Cape Town’s Impending 'Day Zero' Water Shut-Off

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Cape Town in South Africa.

By Betsy Otto and Leah Schleifer

Cape Town is running out of water. After three years of intense drought, South Africa's second-largest city is just a few months away from "Day Zero," the day when the city government will shut off water taps for most homes and businesses.


The impacts of such a shutdown will be devastating. Citizens will have to wait in long lines at state-managed distribution points to receive a mere 25 liters of water per day, less than half the water needed for one average shower. Experts are already warning of public health concerns like poor sanitation leading to faster spreading of dangerous diseases, especially for the city's poorest residents, and forecasting that pipes may crack from dry conditions, endangering future water distribution if and when the drought ends. The Western Cape Premier has warned that "normal policing will be entirely inadequate" to manage the chaos that could ensue.

Although this instance is one of the most extreme, Cape Town is not the only city to suffer from intense water scarcity in recent years. From São Paulo to Los Angeles, cities around the world have made headlines due to severe droughts intensified by climate change and exacerbated by poor water management.

But it doesn't have to be this way. Here are three steps cities around the world should take to boost water security and resilience:

1. Understand Risks

Many cities are experiencing growing water risks. Climate change is shifting cloud patterns and the hydrologic cycle in certain regions, making rainfall more variable and droughts more common and intense. At the same time, the world's cities are growing at a rate of 3 million people per week, increasing competition over scarce resources.

Each city has unique risks it must be aware of. For example, Cape Town has medium-to-high inter-annual variability, meaning precipitation varies greatly from year to year. Although Cape Town has suffered droughts in the past, wet years usually follow, refilling reservoirs that supply the city with almost all of its water. But during the current record drought, reservoir levels have fallen to 25 percent.

In addition, Cape Town has extremely high water stress, which means that the water demands of its population—which has doubled in the past 18 years—are competing for the available water supply with other users. While city officials were aware of these risks and took steps to mitigate them, they did not anticipate rainfall patterns departing so significantly from the norm to culminate in record drought.

Amidst rapidly changing landscapes, cities like Cape Town must carefully measure and forecast the impacts of climate change, population growth and competing demands on their water systems. Tools like Aqueduct and The Nature Conservancy's Urban Water Blueprint can help map the bigger picture, but risks will differ by watershed. Each city must ultimately assess its unique water risks and plan accordingly.

2. Manage Your Water Budget

Cities have finite water resources, whether sourced from nearby watersheds, dams or pumped directly from underground. Where the water originates from differs by location—oftentimes a diverse set of users, such as power plants, farms and homes, compete for this same water. It's a city's job to manage its own water budget in the context of this broader landscape, understanding sources and uses, and allocating resources within these realities.

Water management becomes even more difficult in times of drought. For example, as the Western Cape's reservoirs began to dry in 2015 and 2016, the national government allocated 40 percent of the province's water to agriculture, leaving 60 percent to Cape Town. This controversial decision caused a great deal of debate in local politics, and is now seen as one of many culprits for the current crisis. This situation is common for many cities, but leaves them fighting with other sectors when water supplies decline.

One solution is for city planners and water utilities to undertake proactive, integrated urban water management strategies that consider drinking water, wastewater and urban drainage (stormwater) more comprehensively, helping cities to build greater resilience and efficiency. This method also takes a holistic view of water sources and uses across a city, recognizing that the actions of every stakeholder impacts the others. Amid the nearly six-year California drought, the city of Los Angeles began developing a One Water plan to better manage limited water resources, stave off the impacts of climate change, and slash the city's purchases of imported water by 50 percent.

3. Invest in Resilience

To withstand a changing climate and growing populations, cities must be resilient to the unexpected. Identifying opportunities for rainwater harvesting, dams and underground storage, treating and reusing greywater and wastewater, and investing in water efficiency is key to boosting resilience to drought and increased water competition.

Cities should also look beyond their boundaries and invest in "natural infrastructure" for protection. Green spaces such as forests and wetlands can act as a sponge by shielding cities from floods and storms and regulating flow during dry seasons. Research also shows that pairing natural infrastructure with traditional "grey" infrastructure like wastewater treatment plants can help cities create jobs, buffer against the impacts of climate change and save money on water treatment.

Inadequate built and natural infrastructure compounded the effects of São Paulo's 2014-2017 drought. The city lost more than 30 percent of treated water through theft and leaky pipes. Deforestation of the Amazon disrupted the "rivers of the sky" that regulate rainfall across Brazil, and loss of nearby Atlas forests also destroyed local water systems. São Paulo, Cape Town and other cities should consider natural infrastructure as one of many solutions for resilience to future water shocks.

A Call to Action for Cities

The situation in Cape Town is unique in many ways, but there are common threads that tie it to São Paulo, Los Angeles and cities around the world facing growing water risks. In the countdown to Day Zero, the South African national government and the City of Cape Town are working hard to help residents avoid the drought's worst effects. But other cities should also use this moment as a warning—without better water risk measurement, management and resilience, the next Day Zero could be coming to your corner of the world.

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Farms with just one or a handful of different crops encourage fewer species of pollinating and pest-controlling insects to linger, ultimately winnowing away crop yields, according to a new study.

Up to half of the detrimental impacts of the "landscape simplification" that monocropping entails come as a result of a diminished mix of ecosystem service-providing insects, a team of scientists reported Oct. 16 in the journal Science Advances.

Monocrop palm oil plantation Honduras.

SHARE Foundation / Flickr / CC BY-NC 2.0​

"Our study shows that biodiversity is essential to ensure the provision of ecosystem services and to maintain a high and stable agricultural production," Matteo Dainese, the study's lead author and a biologist at Eurac Research in Bolzano, Italy, said in a statement.

It stands to reason that, with declines in the sheer numbers of insects that ferry pollen from plant to plant and keep crop-eating pests under control, these services will wane as well. But until now, it hasn't been clear how monocultures affect the number and mix of these species or how crop yields might change as a result.

Aiming to solve these questions, Dainese and his colleagues pulled together data from 89 studies cutting across a variety of landscapes, from the tropics of Asia and Africa to the higher latitudes of northern Europe. They tabulated the number of pollinating and pest-controlling insects at these sites — both the absolute number of individuals and the number of species — along with an assessment of the ecosystem services the insects provided.

In almost all of the studies they looked at, the team found that a more diverse pool of these species translated into more pollination and greater pest control. They also showed that simplified landscapes supported fewer species of service-providing insects, which ultimately led to lower crop yields.

The researchers also looked at a third measure of the makeup of insect populations — what they called "evenness." In natural ecosystems, a handful of dominant species with many more individuals typically live alongside a higher number of rarer species. The team found as landscapes became less diverse, dominant species numbers dwindled and rare species gained ground. This resulting, more equitable mix led to less pollination (though it didn't end up affecting pest control).

"Our study provides strong empirical support for the potential benefits of new pathways to sustainable agriculture that aim to reconcile the protection of biodiversity and the production of food for increasing human populations," Ingolf Steffan-Dewenter, one of the study's authors and an animal ecologist at the University of Würzburg in Germany, said in the statement.

The scientists figure that the richness of pollinator species explains around a third of the harmful impacts of less diverse landscapes, while the richness of pest-controlling species accounts for about half of the same measure. In their view, the results of their research point to the need to protect biodiversity on and around crops in an uncertain future.

"Under future conditions with ongoing global change and more frequent extreme climate events, the value of farmland biodiversity ensuring resilience against environmental disturbances will become even more important," Steffan-Dewenter said.

Reposted with permission from our media associate Mongabay.

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