The role of rainwater harvesting in drought-prone areas

Rainwater harvesting is a method of collecting and storing rainwater for later use, and it is becoming increasingly important in drought-prone areas. Drought is a prolonged period of dry weather that can have severe consequences for the environment and communities that depend on water for survival. As climate change continues to worsen and water resources become scarcer, rainwater harvesting is becoming a vital tool for conserving water and reducing the impact of drought.

In the northern hemisphere, the summer of 2022 was one of the worst on record for countries across Europe, North America, and the Middle East in terms of drought.

As reported by BBC News, two-thirds of Europe was under some sort of drought warning, making it the worst such event in 500 years, according to the EU's Global Drought Observatory.
According to the World Food Programme, the number of people at risk of starvation in the drought-ravaged Horn of Africa increased to 22 million in 2022.

The article goes on to say “Years of insufficient rainfall across Kenya, Somalia and Ethiopia have caused the worst drought in 40 years and conditions akin to famine in the hardest-hit areas, aid groups say.

“An unprecedented four failed rainy seasons has killed millions of livestock, destroyed crops and forced 1.1 million people from their homes in search of food and water.”

Whilst European countries are likely to get some respite from the drought during the winter, there is no end in sight for many countries, especially in Africa and the Middle East and rainwater harvesting is becoming an increasingly vital tool in the battle against drought.

Benefits of rainwater harvesting

One of the biggest advantages of rainwater harvesting is that it allows communities to collect and store water during periods of heavy rainfall, which can then be used during times of drought. This not only helps to mitigate the effects of drought but also allows communities to become more self-sufficient and less dependent on outside sources of water.

Another advantage of rainwater harvesting is that it can help to recharge aquifers and other underground water sources. Aquifers are underground layers of rock and soil that store groundwater, and recharge is the natural process by which precipitation and surface water replenish them (USGS Water Science School). However, during times of drought, these aquifers can become depleted. By collecting and storing rainwater, communities can help to recharge these aquifers, ensuring that they will have a reliable source of water during future droughts.

Reducing stormwater runoff

Rainwater harvesting can also help to reduce the amount of stormwater runoff, which can be a problem in drought-prone areas. Stormwater runoff is water that flows over the surface of the ground during a rainstorm, and it can cause serious problems such as flooding, erosion, and water pollution. By collecting and storing rainwater, communities can reduce the amount of stormwater runoff, which can help to prevent these problems.

Stormwater runoff is also caused by growing urbanisation globally. In places where stormwater would previously have been absorbed by the soft soils, the large amount of concrete and asphalt in and around major cities means that this water has nowhere else to run, leading to flooding and other issues.

Rainwater harvesting is not only becoming a vital part of water conservation in more remote areas, but it is an essential cog in the wheel for large towns and cities.

Rainwater harvesting can save money

Additionally, rainwater harvesting can be a cost-effective way of providing water to communities, especially in rural and remote areas where access to water is limited. Building large-scale water supply systems are often too expensive for these communities, and it can be difficult to maintain them. However, rainwater harvesting systems are relatively simple to construct and maintain, making them a more affordable option for these communities.

In countries like New Zealand, Australia and the USA, where drought conditions are not unusual and can affect different parts of the country, we are starting to see more and more homes and businesses investing in rainwater tanks as a way of reducing costs and ensuring they have enough water to remain self-sufficient in the case of water restrictions.

Whilst the upfront cost of installing a water tank can be prohibitive to some, if you plan to remain in a house or commercial property for a significant period of time, they will often pay back the initial cost in a relatively short period of time, saving you money in the long run.

Reduces pressure on municipal water supply

Every litre drawn from a rainwater tank is a litre that doesn't have to be pumped, treated, and delivered through the municipal network. During a drought, this matters at a community level, not just a household one. The more properties that harvest their own rainwater, the more slack is left in the town supply for essential and emergency uses. Councils in drought-prone regions often actively encourage rainwater tank uptake for exactly this reason, since it directly reduces peak demand on reservoirs and treatment plants.

Better water quality for gardens and irrigation

Rainwater is naturally soft and free of the chlorine, fluoride, and dissolved salts found in most treated municipal supplies. This makes it gentler on garden soil and more effective for plants over time, since chlorinated water can gradually disrupt beneficial soil microbes. For properties with vegetable gardens, orchards, or sensitive landscaping, harvested rainwater is often the preferred irrigation source even outside of drought conditions.

A reliable backup during emergencies

Droughts often coincide with, or lead to, other supply disruptions; burst municipal mains, scheduled water restrictions, or power outages that affect pumping stations. A full rainwater tank acts as an on-site emergency reserve, giving households and farms a buffer of usable water even if the wider network goes down. This is particularly valuable for rural and off-grid properties that don't have a fallback connection to a town supply.

Methods of rainwater harvesting

There are many different methods of rainwater harvesting, and the best method will depend on the specific needs and resources of the community. Some common methods include:

· Rooftop rainwater harvesting: This involves collecting rainwater from the rooftops of buildings and storing it in tanks or cisterns.

· Surface runoff harvesting: This involves collecting rainwater from the surface of the ground and storing it in ponds or reservoirs.

· Infiltration harvesting: This involves allowing rainwater to soak into the ground, where it can recharge aquifers and other underground water sources.

Each of these methods has its own advantages and disadvantages, and the best method will depend on the specific needs of the community.

Challenges of rainwater harvesting

Despite the many benefits of rainwater harvesting, it is not without its challenges. One of the biggest challenges is that some rainwater harvesting systems can be expensive to construct and maintain, especially in remote areas.

Additionally, it can be difficult to ensure that rainwater harvesting systems are properly maintained and operated, which can lead to problems such as contamination of the stored water. The cost of maintaining rainwater harvesting systems can be prohibitive, especially in some areas.

Another obvious issue with rainwater harvesting in some countries is that there is simply not enough rain to harvest. As reported by the Guardian, four failed rainy seasons means there simply would not have been the water to harvest in some African nations, so a rainwater harvesting system would be redundant.

Monitoring your rainwater levels

If you already have a tank installed or you are thinking of installing a tank, a great addition is a water level meter that will enable you to see how much water is in your tank at any time. These are particularly useful for large tanks that are used as the main source of water for a property, however, they can be installed on a wide range of water tanks.

How Smart Water can Help

At Smart Water, we have engineered the most advanced tank level indicator available that now offers full cloud connectivity.

Easy to install yourself, your Smart Water tank indicator provides you with all the information you need from our app or from one of our LCD displays. Find out how much water you consume on average from your tank, accurate pressure data and estimates on when your tank will run out of water based on current usage.

Find out more about our range of products or check out our FAQs for more information.

Summary

In conclusion, rainwater harvesting is becoming an increasingly important tool for conserving water and reducing the impact of drought in drought-prone areas. It allows communities to collect and store water during periods of heavy rainfall, which can then be used during times of drought. It can also help to recharge aquifers, reduce stormwater runoff, and provide a cost-effective way of providing water to communities. However, it is important to note that rainwater harvesting is not without its challenges, and it requires careful planning and management to ensure that it is successful.

Frequently Asked Questions

Is harvested rainwater safe to drink?

It depends on the collection setup and how the water is treated. Rainwater collected from a well-maintained roof and gutter system, stored in a clean tank, is commonly used for drinking in many rural areas but it should generally be filtered and, ideally, treated (e.g. UV or chlorination) before use as a primary drinking supply. Untreated rainwater is more commonly used for irrigation, livestock, laundry, and general household use.

How much rainwater can I actually collect from my roof?

As a rough rule of thumb, 1mm of rainfall over 1 square metre of roof yields about 1 litre of water (before accounting for losses from evaporation, overflow, and first-flush diversion). A 100m² roof in an area that gets 20mm of rain, for example, could theoretically capture around 2,000 litres from a single rain event, assuming the collection system is properly sized and maintained.

Do I need a permit to install a rainwater harvesting system?

This varies by country, state, and even local council, so it's worth checking with your local authority before installing a tank, particularly for larger systems, systems intended for indoor/drinking use, or properties on a shared water scheme. Simple garden or irrigation-only setups often face fewer restrictions than systems plumbed into household drinking water.

How do I know how much water is left in my tank?

This is exactly what a tank level indicator is for. Instead of manually checking or guessing, a wireless sender in the tank reports the water level to an app or LCD display, so you can see your remaining supply, track usage trends, and get a sense of how long your water will last at current usage rates which is especially useful for planning through an extended dry spell.

Does rainwater harvesting still work during a long drought?

Rainwater harvesting is most effective as a buffer built up during wetter periods, rather than a solution once a drought is already severe, a tank can only hold water that has already fallen. This is why sizing your tank for your climate and usage, and monitoring levels closely as a drought develops, matters more than relying on harvesting alone once rainfall has already become scarce.