Rainwater harvesting and its benefits
In my childhood, when the elders asked me not to waste water, I thought water was an unlimited resource. At that time, water scarcity was unknown, but now, owing to the drought, overpopulation and congestion, the importance of water cannot be stressed enough.
Madam – Rainwater harvesting and its benefits.
In my childhood, when the elders asked me not to waste water, I thought water was an unlimited resource.
At that time, water scarcity was unknown, but now, owing to the drought, overpopulation and congestion, the importance of water cannot be stressed enough.
There are five elements in life: fire, water, air, earth and the sky. Of these, water has to be the most essential. Water means life. It is said man can live without food for more than one month, but without water man cannot live more than seven days.
Water is so precious that the next war can be about water. We know that about 70 per cent of the earth’s surface is covered with water, but only 3 per cent of the water found on earth is drinkable. The rest is in the form of sea water and ice. Of this pleasant water, most can be found in lakes, rivers and as ground water.
The consumption of water is variable in different parts of the world.
The minimum water intake to maintain body hydration is 1.5 litres per day. Under normal circumstances, about 2.3 litres per person of drinking water is necessary per day.
A family in a village collects only about 10 to15 litres for a whole family of six to eight members. Therefore, rainwater harvesting is the best option to ensure that they almost always have enough supply.
The process of collecting, storing and using of rain water from a catchment surface is called rainwater harvesting. Rainwater harvesting systems are simple to install and operate. Rainwater can supplement the sub-soil water level and increase urban greenery.
In some cases, rainwater may be the only available or economical water source. Rainwater harvesting systems can be simple to construct from inexpensive local materials, and are potentially successful in most habitable locations. Rainwater offers advantages in water quality for both irrigation and domestic use.
It is naturally soft, (unlike well water), contains almost no dissolved minerals or salts, is free of chemical treatment, and is a relatively reliable source of water for households. In KwaZulu-Natal, it is an old practice in high rainfall areas to collect rainwater from roof tops into storage tanks. In foothills, water flowing from springs is collected by embankment type water storage.
Rainwater can be harvested from the following surfaces:
1. Rooftops
If buildings with impervious roofs are already in place, the catchment area is effectively available free of charge and they provide a supply at the point of
consumption. The collection area in most cases is the roof of a house or a building. The effective roof area and the material used in constructing the roof influence the
efficiency of collection and the water quality. A conveyance system usually consists of gutters or pipes that deliver rainwater falling on the rooftop to cisterns or other storage vessels. Both drainpipes and roof surfaces should be constructed of chemically inert materials such as wood, plastic, aluminum, or fibreglass, in order to avoid adverse effects on water quality. The water ultimately is stored in a storage tank or cistern, which should also be constructed of an inert material. Reinforced concrete, fibreglass or stainless steel are suitable materials. Storage tanks may be constructed as part of a building, or may be built as a separate unit located some distance away from the building.
2. Storm water drains
Most of the residential areas have proper network of stormwater drains. If maintained neatly, these offer a simple and cost effective means for harvesting rainwater.
Oneof the beauties of rainwater harvesting systems is their flexibility. A system can be as simple as a barrel placed under a rain gutter downspout for watering a garden, or as complex as an engineered, multi-tank, pumped and pressurised construction to supply residential and irrigation needs.
3. Rainwater harvesting systems are integrated with the house, which makes water easily accessible.
4. The used materials can be kept simple, are obtainable nearly everywhere at local (low) cost price.
5. The construction is easy and cheap in maintenance.
Mbali Mahaye, KwaZulu-Natal Department of Water & Sanitation: Communications
