Your Water Footprint

In South Africa, water is a scarce commodity with an average annual rainfall of approximately 464 mm compared with a world average of 860mm, according to the Wildlife & Environment Society of South Africa (WESSA). So it’s important that we maintain an extremely water wise approach to daily living.

Have you thought about your water footprint?

Your water footprint is the total amount of water that you use in your daily life. It is the ‘direct’ water use in your home plus the ‘hidden’ water used to produce your goods and services.

Everything we use, wear, buy, sell and eat takes water to make.

The water footprint measures the amount of water used to produce each of the goods and services we use. It can be measured for a single process, such as growing rice, for a product, such as a pair of jeans, for the fuel we put in our car, or for an entire multi-national company.

The water footprint is a measure of humanity’s appropriation of fresh water in volumes of water consumed and/or polluted.

According to the Water Footprint Network, there are three water footprints:

Green water footprint is water from precipitation that is stored in the root zone of the soil and evaporated, transpired or incorporated by plants. It is particularly relevant for agricultural, horticultural and forestry products.

Blue water footprint is water that has been sourced from surface or groundwater resources and is either evaporated, incorporated into a product or taken from one body of water and returned to another, or returned at a different time. Irrigated agriculture, industry and domestic water use can each have a blue water footprint.

Grey water footprint is the amount of fresh water required to assimilate pollutants to meet specific water quality standards. The grey water footprint considers point-source pollution discharged to a freshwater resource directly through a pipe or indirectly through runoff or leaching from the soil, impervious surfaces, or other diffuse sources.

Consumers can reduce their direct water footprint in their home by installing water saving toilets, applying a water-saving showerhead, closing the tap during teeth brushing, using less water in the garden and by not disposing of medicines, paints or other pollutants down the sink.

But there is more to your water footprint than that. For example, think about how much water is used to make a pair of jeans. According to Stephen Leahy’s book Your Water Footprint (Firefly Books Ltd), it takes 7,600 litres of water to make your favourite pair of jeans. That includes growing the cotton and manufacturing the garment, but it doesn’t include the water that you’ll use to wash your jeans over time.

Food production places just as much pressure on this valuable resource. The food we eat makes up more than two thirds of our total water footprint, mostly because of all the “virtual water” needed to produce that food. Studies done by the Department of Water show that the vast majority of water in South Africa is used in agriculture, with over 60% of all available water being used for irrigation.

Virtual Water refers to the amount of ‘hidden’ water used to produce a product (e.g. a chocolate bar) or a service from start to finish. According to WESSA a portion of chicken takes 975 litres of water, while one portion of beef uses 1900 litres.

Leahy suggests: “If a family of four served chicken instead of beef they’d reduce their water use by an astonishing 900,000 litres a year. That’s enough to fill an Olympic size pool to a depth of two feet. If this same family opted for Meatless Mondays, they’d save another 400,000 litres. Now they could fill that pool halfway.”

Smallholders growing vegetables must make water wise choices. Add compost to the soil in your veggie garden to provide nutrients to plants and increase the water holding capacity of the soil. Consider adding water retention granules to the soil to increase its water holding capacity. Mulch your veggie garden to conserve soil moisture.

Group plants with similar water requirements together to create different hydro-zones, and irrigate each hydro-zone accordingly. Some gardeners plant vegetables in amongst their flowers, taking advantage of the watering regime in the flower garden.

When watering:

Avoid applying water faster than the soil can absorb it;

Water at the right time of day;

Water according to your soil type;

Avoid watering your garden on windy and hot days, as the evaporation rate is higher;

Water deeply but less frequently. Deep soakings encourage roots to grow deeper and utilise moisture deep in the ground, which enables plants to thrive between watering;

Consider using drip irrigation throughout your garden, so that the water goes precisely where it is needed.

To find out more about your water footprint, click here.