Rainwater is water that falls directly from clouds. It is one of the purest forms of water since it comes straight from its source. In the midst of climate change and its threats of longer periods of droughts (and consequently water shortage), harvesting rainwater is a good means to preserve this resource and also save money in the long run.
Potable water is obtained primarily from boreholes while the rest is withdrawn from reservoirs and rivers. While 99.6% of the population has access to potable water, few households, especially those found in the squatters group, get water from water tanker services. Based on statistics, water consumption keeps on increasing; for instance, water consumption for the years 2012 to 2016 have increased from 214 litres per day to 225 litres per day.
Mauritius has a serious water shortage problem. This is mostly due to the lack of appropriate technology and implementation projects concerning the water resources. To date, several regions throughout the island, ranging from towns to villages, face the problem of water cuts during a 24 hr period. What’s more, based on IPCC model simulations, rainfall in the Southern Indian Ocean is expected to decrease by 8% in the next 50 years. In this respect, it is vital to come up with means to save water and exploit the resources that are already freely given on the island.
When rain falls, only 10% of the water goes into underground reserves while most of it, 60%, is lost as runoff (remaining 30% evaporates). Rather than losing so much water to canals and eventually to the sea, this water is harvested and used for everyday purposes such as irrigation.
Water falling on the roof is directed to a water tank through the gutters. This water is stored and treated as needed depending on its use. While water to be used for household chores does not require much treatment, water for cooking and drinking must be treated to kill microbes. A system of pipes is then installed from the tank to the different outlets in the house or garden to let the water out. Maintenance is only in making sure that the gutters remain clean and to check on the water tanks regularly.
Greenhouses have adopted rainwater harvesting to meet their water requirements while at the same time lowering their water consumption bills. These sites require a lot of water for the proper running of the plant. Strategies like rainwater collection allow them to embark on environmentally friendly projects and educate people on resource conservation.
According to the Rainwater Harvesting Association, collection of rainwater can reduce water bills by up to 40% if this water is used for washing clothes and flushing toilets. As more stress is laid on water resources, it is imperative to come up with alternatives. Harvesting rainwater from houses does not require much trouble.
Land cultivation is an activity that requires much water. Plants sometimes have to be watered several times a day and this costs money. One way to achieve water freedom in this respect is to harvest rainwater in manmade ponds. The ground is dug deep enough for water storage and then covered with a sheet of plastic to prevent it from seeping into the ground. The water can then be covered once it is full to prevent evaporation and breeding of mosquitoes.
Businesses, hotels, golf courses, public gardens and schools can also launch rainwater harvesting projects as part of their contribution towards sustainability and education.
If proper actions are taken, water scarcity will not be such an issue in Mauritius in the coming years.