Urban Agriculture to the Rescue
São Paulo, Cairo, London, Bangalore, and Tokyo. Five cities from different parts of the world. Each representing distinct socio-economic, cultural, political demographic and climatic conditions. Yet all these cities have one thing in common: they are headed towards severe water security issues in the immediate future.
Sao Paulo, Brazil’s financial capital, faced a major water crisis in 2014 when its reservoir supply capacity fell below 4%. Though the city has since recovered from this crisis, it is headed towards another one soon due to polluted reservoirs, impaired infrastructure and deforestation of the Amazon rain forest.1,2
Cairo is currently drawing 97% of its freshwater from River Nile. The river is also the receiver of untreated agricultural and residential waste, which is deteriorating its water quality. Poor water quality and increasing population are expected to cause a water shortage in the city by 2025.1,2
London, the famously rainy city, is not the first that comes to mind when thinking about water scarcity. Yet population increase and weakening infrastructure are leading the city to face a supply shortage by 2025. 1,2
Bangalore, the booming tech hub, has experienced unprecedented growth in the last decade. This put tremendous strain on the city’s water resources and distribution infrastructure. Furthermore, water pollution has rendered most of the freshwater sources of the city unsuitable for residential use. As a result, the city is already facing a serious water shortage.1,2
Tokyo, the most populated city in the world, enjoys abundant rainfall. However, most of this rainfall is concentrated in just four months of a year. Therefore, city faces a shortage of water whenever there is a dry spell in terms of rainfall. And these dry spells are expected to occur more frequently in the future due to climate change, putting the city’s water supply in grave danger.1,2
These cities represent the world’s urban population. The trend of urbanization observed throughout the world is changing the water demand and distribution scenario. In their current state, urban areas are huge sinks for freshwater resources. Despite the strain being put on the water resource due to human activities, in many situations, water resource is available in abundance. Still, due to miss management and poor governance, water is wasted, leading to its scarcity. Hence, concentrated efforts are needed to improve water management to keep our cities from entering dire water-scarce conditions.
The practice of cultivating and distributing food in and around urban areas, known as urban agriculture, is gaining momentum worldwide. It is being looked at as a circular approach to manage resources to create a more sustainable urban food-energy-water nexus3 and can be a solution to the water challenges faced by cities. Linking urban agriculture to water usage has the potential to improve water management by reducing, reusing and recycling the resource.3
Newer urban agricultural systems such as aquaponics and hydroponics, are good ways of recycling domestic waste. Studies have shown that hydroponic systems can use secondary treated domestic waste to produce commercial food crops4. Proper retention time designs can assure sufficient nutrient supply for the growing crops4. The nutritional quality of the produced food crops is comparable to commercially available products4. Thus, urban agricultural systems allow for safe reuse of wastewater by recycling nutrients. They also have additional benefits in terms of energy and cost conservation. Furthermore, effluent coming out of these systems can be further used for other purposes. Thus, urban agriculture ensures efficient cycling of water resource at reduced economic, energy and environmental cost. Hence advancement of urban agriculture would be a boon for water conservation in urban water-stressed areas.
Apart from the challenges of water management, urban agriculture has the potential to minimize the effect of other environmental challenges such as air pollution, carbon emissions, global warming, and biodiversity loss. It is a multipurpose tool for environmental protection. Though more investigation is needed to make urban agricultural systems more efficient and risk-free, there is no doubt in my mind that for cities drowning in water and environmental worries, urban agriculture will come to the rescue.
- The 11 cities most likely to run out of drinking water – like Cape Town. (2018). BBC News. [online] 11 Feb. Available at: https://www.bbc.com/news/world-42982959.
- Chapman, W. (2019). 10 Cities Most At Risk of Running Out of Water. [online] US News & World Report. Available at: https://www.usnews.com/news/cities/slideshows/10-cities-most-at-risk-of-running-out-of-water?slide=11.
- Skar, S.L.G., Pineda-Martos, R., Timpe, A., Pölling, B., Bohn, K., Külvik, M., Delgado, C., Pedras, C.M.G., Paço, T.A., Ćujić, M., Tzortzakis, N., Chrysargyris, A., Peticila, A., Alencikiene, G., Monsees, H. and Junge, R. (2020). Urban agriculture as a keystone contribution towards securing sustainable and healthy development for cities in the future. Blue-Green Systems, [online] 2(1), pp.1–27. Available at: https://iwaponline.com/bgs/article/2/1/1/71141/Urban-agriculture-as-a-keystone-contribution [Accessed 19 Apr. 2020].
- Noraisha Oyama (2008). Hydroponics system for wastewater treatment and reuse in horticulture. [online] ResearchGate. Available at: https://www.researchgate.net/publication/43981067_Hydroponics_system_for_wastewater_treatment_and_reuse_in_horticulture [Accessed 26 Jan. 2021].