Water, water everywhere…but not a lot to drink. Despite being on the rainiest places on the planet, Colombia’s Chocó department has a serious lack of clean water. Rainwater harvesting is how one group are working to fix it.
The Chocó is one of Colombia’s most beautiful corners, touching both the Atlantic and Pacific oceans, and is also its wettest, recording a staggering 13,000 mm – yes, that’s 13 metres! – of rain a year in some areas. The main city of Quibdó gets at least a respectable 8,000 millimetres and 300 rainy days a year. So there’s no shortage of good water? Right.
Wrong. Water, waste and sanitation systems are sub-standard across the region – one of the most impoverished in the country – and particularly in urban communities like Quibdó locals can’t rely on clean drinking water coming out of a tap. Instead they are forced to use contaminated supplies or fork out cash to buy packaged water in the corner shop.
This is because in Quibdó the public water is piped to less than 50% of the 115,000 inhabitants and only about 11% have a sewage connection. Hence, it’s common to see packaged drinking water sold in plastic bags and bottles, which not only contributes to the rubbish pile but also adds economic stress to already poor communities.
Part of the problem is the polluted rivers. Quibdó lies on the banks of the River Atrato, which like many Chocó rivers is polluted with heavy metals like mercury from illegal gold mining and contaminated by sewage discharge because of the lack of wastewater treatment.
Finding solutions to these problems can be challenging. For decades the Chocó has been the epicentre of social and environmental conflicts driven by clandestine activities – gold mining, coca growing and illegal timber industry – and large public infrastructure projects are hard to get off the ground.
One answer is household harvesting of the ample rainfall from rooftops, allowing families to collect and control their own water supply. There are still contamination issues – the water can get dirty on the rooftops – but with the appropriate intermediate technology a steady clean supply can be achieved.
With this plan in mind, the Bogotá-based company VIC has set up a pilot project in Quibdó to collect rooftop rainwater and install cleaning filters made from materials available at local hardware shops and sand, gravel and stones procured locally.
The pilot plan is in place with collaboration from the Escuela Robótica de Chocó (The Chocó School of Robotics), an innovation centre based in Quibdó giving students a doorway into the world of technology. Students from the school have won several international accolades and have just returned from representing Colombia at the world championship of robotics in China.
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The school’s founder Jimmy García is also at the forefront of environmental activism in the Chocó and welcomes the rainwater harvesting project.
He told us: “This project is important because it gives access to potable water to the communities using a low-cost system that is easy to build, maintain and is easily replicable. It helps us remove the dependence on the public utility companies and is a sustainable way to potabilise water. Hence our decision to implement.”
The pilot’s objective is to demonstrate to communities how they can harvest the eternal rainfall, but also treat it using a low-cost ‘do-it-yourself’ system that local people can replicate.
In the plan, water is collected by guttering on 100 square meters of rooftop, then sent through down-take pipes through a centrifugal filter (called RAINY FL 100) which removes large particles, than piped to a large tank which feeds a second slow filter of stones, gravel, sand and activated carbon. This removes smaller physical contaminants and allows for natural biological disinfection of the water. The clean water can then be stored in barrels for household use. The system requires minimal maintenance and has high treatment efficiencies of over 99%.
VIC believes the average household in Quibdó can harvest approximately 2,000 litres of rainwater every day – four times more than the average daily water demand – and filters treat between 300-500 litres of water per day.
The pilot plant was set up in just two days and cost approximately $2,000,000 COP. While this amount could be seen as a high initial cost for many households, it could be achievable with a microfinance plan: as it is at present households spend on average $50,000 per monthly on purchased drinking water, so in the longer term rainwater harvesting can reduce the financial burdens while giving access to safe drinking water.
Access to clean drinking water is a basic human right and in regions like Quibdó, where water is available in such abundance, sustainable decentralised systems must be implemented instead of waiting for the utility companies to do the same.
Author Vishwas Vidyaranya is the Technical Director of VIC SAS, Bogotá. He is a sustainability expert with over nine years of experience in India, Germany and Colombia in water and waste management systems.