The convenience of acollection of rainwaterit all depends on the initial investments and the use you intend to make with the collected rainwater. Therecollection of rainwaterit is a very ancient practice, in the home garden it is possible to prepare open tank bins, or rather, covered only with a tight-meshed net that can act as a sieve for leaves and other elements carried by the wind.
In this context, a system ofrecovery of rainwaterit is extremely sustainable from every point of view: it is inexpensive (indeed, the price could be zero using a recycled plastic bin) and allows you to partially satisfy the water needs of the plants in the garden or fully satisfy the needs of cultivation on the terrace and balcony. Indeed, a system ofcollection of rainwater, from this point of view, it could be very useful on those terraces that lack a water connection.
The situation is very different when considering a system ofrecovery of rainwater for irrigation of the fields. With this in mind, the initial investment could be (for many) prohibitive, especially in consideration of the large quantities of water to be collected and especially if you do not want to sacrifice a lot of space and intend to design a rainwater recovery system with tank. underground or with filters. To learn more about this topic, we refer you to the articles
- Plant for the recovery of rainwater
- Notes on Recovery of rainwater
- Rainwater recovery system, when is it convenient? The preliminary assessments
On this page, we will bring you a practical example.
To design a system ofrecovery of rainwaterit is necessary to study the surface available for harvesting and the rainfall in the area. In general, we can say that:
- the smaller the area to be devoted to collection, the more inconvenient (from an economic point of view) it is to install a rainwater recovery system.
- It is always necessary to relate the size of the tank not only to the collection surface and to the average rainfall of the area (so as to make careful choices), especially to the fields to be irrigated: if the area to be used for collecting rainwater is small while the lawn or the field to be irrigated is 1,000 square meters, the water collected will only be enough for a few months or even weeks, making the investment convenient only if there is no way to connect to the water supply in the area.
Rainwater collection, practical example
Considering the rainfall of the Po Valley (about 800 mm, average annual rainfall) and analyzing the possibility of installing a cistern for the collection of rainwaterwith a capacity of 80 cubic meters, it will be possible to have a maximum of 80,000 liters of water.
On average, this amount is enough to meet the water needs of a 500 square meter garden for four months.
At initial costs, it is not only the tank and installation that must be considered. A system ofcollection of rainwaterrequires a submersible electric pump which, in addition to the initial cost, needs a good dose of electricity to work.
In the photo above, a gutter that could increase the collection surface by conveying a fair amount ofrain water in the tank.