Collecting rainwater is one of the most accessible and economically viable options to deal with the freshwater crisis.
Experts estimate that by 2025, 1.8 billion people will live in regions with absolute water scarcity, and two-thirds of the world’s population will be living under water-stressed conditions.
The primary driver of this water scarcity crisis is population growth; it is projected that the world population will reach 9.7 billion by 2050. In addition to the direct effect of population growth on water availability, increased demand for water also results from economic development and changing lifestyles.
For example, as societies become more industrialized and personal incomes rise, there is an increase in meat consumption (which requires large amounts of water for livestock production). Industrialization has also led to a shift from subsistence farming to cash crops (which are often grown in water-intensive irrigated systems).
These changes put even more strain on already limited water resources.
Climate change is also expected to exacerbate the freshwater shortage crisis, as droughts become more common and extreme weather events increase flooding and pollution.
With so many factors contributing to the freshwater shortage crisis, it is clear that we must rethink our approach to water to address this pressing global issue. We can start by harvesting and storing rainwater.
This guide looks at rooftop rainwater harvesting methods, highlighting what you need to get started and the different ways you can use rainwater to build a more water-resilient future.
Rooftop rainwater harvesting: What you need
Rooftop rainwater harvesting is a type of water conservation practice that involves the collection and storage of rainwater from a building’s rooftop.
You can then use the stored rainwater for various purposes such as irrigation, domestic use, or even recharging groundwater aquifers. Rooftop rainwater harvesting helps to reduce the strain on surface water resources and can also save money on water bills.
So, what do you require to start harvesting FREE rainwater? We compiled a detailed guide on rainwater harvesting for homeowners. But, to recap, you’ll need:
- Catchment: A surface that directly receives rainfall, in this case, your roof. You can also harvest rainwater from your terrace, paved surfaces, etc.
- Pipes/drains: After catching the rainwater, you must transport it to the storage system. Most rainwater harvesting systems use UV-resistant water pipes (PVC) and gutters for sloping roofs, feeding water to the pipes and down to storage.
- Filter: Rainwater should pass through filters to remove harmful microorganisms and turbidity. You can use a simple mesh, sand, and gravel filter on top of your storage tank to remove leaves, dust, silt, and other organic matter from getting into the storage tank. Just remember to clean out your filtration system regularly.
- First flush device: This device is used to flush out the first shower and prevent it from contaminating water in the storage tank. When it’s not raining, your roof collects dust and even droppings from birds, etc. When it rains, all these contaminants flow into your water tank hence the need for a first flush.
Easy rooftop rainwater harvesting methods
With your rooftop rainwater harvesting system in place, the fun part begins; storing all that water for present and future use. Following are a few excellent rainwater harvesting ideas.
Harvest rainwater for direct use
You should fit all your rainwater storage tanks with a filtration system and an excess water overflow system. For instance, you can use the excess water to recharge other water facilities.
Using rainwater for secondary activities slashes your water bills and saves energy that would have been used to pump water to your doorstep.
Recharge dug wells
You can divert harvested rainwater to recharge wells on your property. The water should first pass through a filtration system to remove organic matter before emptying into the well. You should also consider desalting and cleaning your dug well regularly to enhance the recharge rate.
Feed groundwater aquifers
Groundwater aquifers are a critical source of fresh water for many communities. However, they become depleted over time due to factors such as drought and excessive pumping. One way to recharge groundwater aquifers is by harvesting rainwater from rooftops.
Rainwater harvesting is an effective way to recharge aquifers because it mimics the natural water cycle. When rainwater seeps into the ground, it replenishes aquifers and helps to maintain a healthy water balance.
In addition, rainwater harvesting can also help to reduce flooding and erosion. By utilizing rain harvesting, communities can effectively recharge groundwater aquifers and ensure a reliable source of water for years to come.
Harvest rainwater into recharge pits
A recharge pit is a small pit built with stone or brick to keep it sturdy. The hole is typically a meter or two wide and 2-3 meters deep. However, you can build a bigger one depending on your rainwater catchment area.
These pits, in turn, recharge shallow aquifers and can also store water for secondary home use.
Creating a water-resilient future
A water-resilient future means having the ability to withstand and recover from disruptions to our water supply. It is a future where we are prepared for drought, floods, and any other event that might impact our water availability. One way to create a more water-resilient future is through rainwater harvesting.
In many parts of the world, water is becoming an increasingly precious commodity. Droughts are becoming more common, and the water demand will only increase as populations continue to grow.
We can start addressing this problem now by rethinking our approach to rainwater harvesting.
Currently, rainwater is often seen as a nuisance, something to be disposed of as quickly as possible. However, if properly collected and stored, rainwater can be a valuable resource. We can use it for irrigation, household cleaning, and even drinking in emergencies.
Rainwater harvesting is not a new technology, but it has been gaining popularity recently as the need for a more water-resilient future becomes more apparent. With proper planning and execution, rainwater harvesting can play an essential role in creating a more sustainable and secure water future for us all.