Irrigation has been used for centuries to help the plants grow: first in agricultural production and later in other areas such as gardens, municipal parks and golf courses. Landscape irrigation refers to an irrigation system is designed to support the trees, plants, shrubs and grass in these areas. Water is consumed in large volume in irrigation systems and it being a scarce resource especially in dry and arid areas, landscaping can become problematic and expensive. One of the ways to reduce the cost of supplying water for irrigation is a method called rainwater harvesting.
Rainwater harvesting refers to the collection, accumulation and storage of water for re-use for various purposes ranging from drinking (after suitable treatment) to irrigation, before the water reaches the wet underground layer of water-bearing materials or rocks known as the aquifers.
Water harvesting from rain is a technique that has been in use for hundreds of years by the people residing in desert or arid areas. In the earliest times, rainwater would be collected in cisterns and then put into porous clay pots that would be buried beside plants to provide a gradual release of water.
The collection areas for rainwater in those days might have been the roof of a building or areas such as terraces and courtyard could have water piped to a collection point, usually an underground cistern. These systems are known as the rainwater catchment systems. The methods used today are basically the same, but the availability of electric pumps instead of relying on gravity to move the water has allowed irrigation in areas that were previously impossible.
The rain water is filtered at its catchment area such as a roof by using a rainwater filter, which stops debris and dirt from traveling to the storage vessel or the rainwater collector. The filter unit is made of filtering media such as coarse sand, fiber or gravel layers. The rain water collected can be used for several purposes including as a supply to the rainwater irrigation system. Graywater systems are also available-the term refers to the re-use of water that has been used for domestic purposes such as washing clothes or household utensils, and bath or shower water.
Rainwater irrigation is one of the most efficient and inexpensive methods of irrigating a landscape. The water is pure as it does not contain chemicals and toxins that may be present in the water supplied by the local municipal authority, nor does it contain the run-off pollution that contaminates many of the rivers and lakes. It is also cheaper as the water is collected from the rainfall using the existing infrastructure such the roof and costs nothing to acquire, after the system is purchased.
Rain barrel drip irrigation is a system where the water is directed from a rain barrel to the point where the water is needed. This method is also known as the gravity-fed drip irrigation system as it relies gravity rather than electric pumps to deliver the water.
Householders can easily take advantage of a rainwater harvesting system whether it is a simple rainwater system consisting of a rainwater barrel to be used with a watering can, or a more elaborate system with a timed, piped delivery mechanism. In either case, the seeking the advice of a professional irrigation contractor will prove to be worth the small investment.