Rainwater harvesting, a response to the water problem in Puerto Rico
Rainwater cistern at Plenitud PR’s farm in Las Marías, Puerto Rico.
Water is a basic and essential element for the development of life as we know it. 75% of the human body is water and 73% of the planet is water. Coincidence?
97% of the planet’s water is found in the ocean in the form of saltwater, followed by water in the form of ice (2%), and even less is freshwater (1%), which we find in rivers, lakes, streams, and aquifers. The rain is in charge of maintaining these bodies of water at a healthy level. The water cycle, or hydrological cycle, permits the existence, continuation, and transformation of life on the planet. Without water, we simply would not exist.
Rafael Mendoza, neighbor of Bo. Purísima Concepción in Las Marías, PR, with his rainwater harvesting system installed by Plenitud PR in 2019.
After the passings of Hurricane Irma and María in 2017, when large portions of the archipelago were without electricity, telephone, and water services for several months, the collective mentality of the contemporary Puerto Rican people was forever changed.
In these moments, we could see firsthand the fragility of the essential services systems of the archipelago. Currently, a majority of the reservoirs in Puerto Rico are sedimented, which reduces the ability to store water, and more than 60% of the water treated in Puerto Rico is lost through the pipes. The droughts of 2014-2016 in Puerto Rico alerted us also to take proactive actions in relation to the management, distribution, and conservation of water in the nation.
The installation of rainwater harvesting systems is an accessible resource that can make a difference in the access to the vital resource of water, especially in moments of natural disasters. The rainwater can be used for basic household chores like flushing toilets and cleaning clothes and the home. But, it is very important to remember that the water collected in this form is not drinkable unless it is filtered, boiled for about five minutes or treated by chemically disinfectants like iodine or chlorine.
By empowering and educating people and communities in rainwater harvesting, they have the power to adapt and maintain strong access to resources before any natural disaster. As part of the educational work that takes place at Plenitud PR, we share with you some advice and tools that can help in the creation of your own rainwater collection system.
Tips for your rainwater harvesting system:
Illustration by Rebekah Sánchez.
Select the catchment area
It can be a zinc roof or a cement roof with gutters. The larger the roof or catchment surface area, the larger amount of water that can be collected.
Carefully observe the water's behavior
Observe the roof or catchment area carefully and analyze how it affects the movement of the water, like this you can identify the best exit for water to connect to your rainwater harvesting system.
Choose the material for the system’s pipes
The gutters or pipes that transport the water from the roof to the reserve area (tank or cistern) are necessary to be able to store water. If you have a zinc roof you can use sanitary 3” PVC pipes as gutters - this is the cheapest option. Another option for zinc roofs are galvalume gutters, which are more expensive but more durable. If you have a cement roof with gutters you can use SCH40 PVC pipes to transport the water. SCH40 pipes are more costly than the sanitary ones but are more resistant in the long term. The price of the pipes will vary based on size. It is recommended to build the system with 2” pipes, though this should be adjusted based on the size of the catchment area. Another aspect that you can integrate for durability is to paint the tubes with a dark color of spray paint. This will protect against the sun and help the pipe to last for a longer period of time.
Choose the size of your rainwater reserve
The cistern or tank is one of the most important details of the system. The price of cisterns can vary depending on its size and material. The easiest and most economical way to start a rainwater harvesting system is starting with a 55-gallon tank. If you live in a place where it does not rain much, it is recommended to use larger reservoir tanks to be able to catch more water and yield more. It is recommended to use sealed cisterns and dark colors to reduce the amount of sunlight permitted, which can cause algae to grow in the water.
Create a base for the cistern
Place the cistern on a base about 2 feet high. This will facilitate access to the water, which will allow you to see directly into the tank.
Make sure you have the necessary tools
With basic tools like a hacksaw, PVC pipe cutter, PVC pipe glue, sandpaper, teflon, measuring tape, silicone, drills, and screws you can assemble a basic rainwater harvesting system. Other tools such as a saws-all or hole saws are also recommended.
Include an overflow pipe
The collection systems should have an overflow pipe so that if the cisterns is already at its maximum capacity, the excess water can flow out. The overflow mechanism can be done in two ways: placing an additional pipe with an outlet to a trench or infiltration pond for the overflow of water that can not be stored or making an open-mount system through which the water enters and comes out the same way.
Use your creativity
There is no exact model for how to prepare a rainwater harvesting system, it is always going to vary case-by-case. Use your observations and creativity in the process!
Illustration by María Alejandra González Pesquera.
We hope that this advice will be useful to you. There is more information about rainwater harvesting in our book: ¡Siembra Boricua! Manual de agricultura en armonía con la naturaleza (Available in Spanish). We offer courses and workshops focused on this topic, so keep an eyes out on our Facebook and Instagram pages, and subscribe to our newsletters so you can receive announcements of new events.
The times are changing and becoming resilient and self-sustaining is essential for the survival of our species. We should remember that we are a part of nature and that by re-immersing ourselves in the sustainable techniques of our ancestors, we reconnect with more harmonious ways of living. This starts one step at a time - little by little, a small chance we can create an ideal reality that we want for ourselves and future generations.
The power is born from within: we have the power to create the world we deserve!
