As rainfall patterns have changed along with the changes in climate, advancements in technology have made the ancient practice of harvesting water more practical and sustainable.

Malaysia is blessed with rain throughout the year and harvesting rainwater for non-potable use such as watering the garden, cleaning the porch or other external uses can reduce the demand for valuable treated water.

What is rainwater harvesting[1]?

Simply put, rainwater harvesting is the process or technology used to conserve rainwater. Rainwater is collected from rooftops, parks, roads, and open grounds that is then diverted, stored, and finally purified for later use.

A rainwater harvesting system can range in size and complexity. All systems have basic components, which include a catchment surface, conveyance system, storage, distribution, and treatment.

Implementing rainwater harvesting is beneficial because it reduces the demand on the existing water supply, reduces run-off, erosion, and contamination of surface water.

It is also a less expensive way compared to desalination or piping water long distances for home use, such as gardening, watering livestock, and on a larger scale – agriculture and farming.[2]

Why harvest rainwater?

Collecting rainwater is a practice that has existed since ancient times as cisterns for storing rainwater have been found in communities as far back as the Neolithic period[3]. Based on research by anthropologists, being able to capture and store water went hand-in-hand with the development of agricultural land.

Today, rainwater harvesting is used for many of the same reasons that existed in those ancient times. Typical uses of rainwater include landscape irrigation, washing applications, ornamental pond and fountain filling, cooling tower make-up water, and toilet and urinal flushing.

With additional filtration and disinfection, harvested rainwater can also be treated to potable standards to supplement municipal potable water supplies to facilities[4].

How can rainwater be used?

The most basic rainwater harvesting systems include a way to collect the rain, a way to direct the water and a place to store the water. However, with the lack of filtration and proper storage, water collected from this simple system is only suitable for basic uses like watering a garden, cleaning the porch, or as grey-water recycling[5].

A more complex system would provide more potential end uses for the water. Such a system would include a collection system with several layers of filters to keep dirt and debris out of the water supply.

For larger scale buildings, the implementation of rainwater harvesting can fulfill multiple roles. Rainwater harvesting can be utilised by incorporating the flow and storage systems with the building’s cooling system. Additionally, newer buildings that have been certified under Malaysia’s Green Building Index have adopted using rainwater for greywater recycling.[6]

 

Other benefits of rainwater harvesting

With the abundance of rainfall year-round, Malaysia is in a prime position to reap the benefits of rainwater harvesting. These benefits go beyond reducing demand on local freshwater resources.

With yearly flash floods that plague many cities in Malaysia during the monsoon season[7], the implementation of rainwater harvesting systems can reduce stormwater runoff, which can overwhelm local sewage systems and result in local pollutants causing contaminations as they make their way to rivers, streams, lakes, ponds, and the ocean. 

Additionally, with proper city planning, rainwater harvesting systems can also reduce erosion in environments where it is common and reduce flooding in low-lying areas[8]

Whether it is a custom-designed system or a simple rain barrel collection, harvesting rainwater is a smart and sustainable choice.

 

References

[1] Dr. R. K. Sivanappan: Rain Water Harvesting, Conservation and Management Strategies for Urban and Rural Sectors (2006)

[2] Jaymi Heimbuch: How Desalination Works (2018) https://www.treehugger.com/how-desalination-works-4858597

[3] Stavros Yannopoulos et al. – Historical development of rainwater harvesting and use in Hellas: A preliminary review (2016)

[4] https://www.energy.gov/eere/femp/alternative-water-treatment-levels

[5] https://greywateraction.org/greywater-reuse/

[6] https://www.greenbuildingindex.org/2010/01/26/rainwater-harvesting-could-be-made-compulsory/

[7] Nurul Afzan Binti Musa Hasni – the peninsular malaysia flooding – a spatio-temporal analysis of precipitation records (2014)

[8] Nor Hafizi et al. – A Review of Rainwater Harvesting in Malaysia: Prospects and Challenges (2018)