Trees, both in the forest and in the city, play an important role in the hydrological cycle by reducing the risk of flooding. The retention of vegetation is able to effectively support not only soil retention, but also ground retention. This is because diverse vegetation simultaneously absorbs and stores moisture, actively participating in the infiltration process. Furthermore, it is largely responsible for avoiding soil erosion by slowing down surface runoff.
Ecological function of the forest
Rainwater retention – by means of the properties of the forest soil – has a positive effect on runoff. This is due in large part to the topsoil, which is protected by undergrowth, mulch, underbrush and, above all, tree crowns. This allows most of the rainwater to soak into the soil and then drain off very slowly. Thanks to the presence of highly absorbent organic soils, rainwater is still “looked after” for some time by the forest vegetation, especially trees.
Forests are responsible for the natural regulation of water relations, acting over vast areas to reduce the risk of flooding. Thus they have a great influence on agricultural crops and even on the water supply of cities, settlements and industrial facilities.
Natural retention reservoir
Forests, like peat bogs and soil, act as natural retention reservoirs, effectively protecting against floods which can cause huge damage. This is why it is so important to take care of vegetation that is able to collect and retain water. In the event of drought, the forest gives back the stored water, regenerating itself. At the same time, it is in charge of the rivers, guaranteeing biological flow. As a result, it is possible to obtain water for the industrial and agricultural purposes.
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Natural retention reservoirs are maintained by the State Forests staff, who additionally choose to enhance retention by reconstructing existing natural retention capacities. This is necessary so that rainwater does not run off too quickly. This applies especially to mountain forests, as their natural retention capacities allow the regulation of water resources in river basins. Deforestation of these areas and consequent soil erosion or soil drought must therefore be prevented.
Look after the urban vegetation!
Apart from the obvious aesthetic reasons, trees have a very practical function – they lower the temperature, create cool, shady places for protection from the sun, and absorb many pollutants such as NO, PM, SO2, O3 and greenhouse gases, including CO2. The leaves of trees act as filters: through a process of gas exchange, they absorb the air together with dust and chemical compounds, and they do so extremely effectively: dust in urban spaces can be reduced by up to 75%! Trees produce vital oxygen and contribute to reducing greenhouse gases.
Fot. by Pixabay
However, the most important – and most difficult – task is to retain water, increase retention and prevent the soil from drying out. If we do not take care of the drainage system, there is a risk of sewage failure and periodic flooding. In urban conditions, all vegetation has a beneficial effect on retention phenomena. Unfortunately, as a result of accelerated surface run-off and lowered groundwater table, maintaining green areas and parks in the city is becoming increasingly difficult and expensive. If nothing is done, trees dry out and green areas in cities gradually disappear as a result of these phenomena and urbanisation. Trees are cut down and replaced by shopping centres or supermarkets, which, without ensuring retention, is an example of anthropopression, i.e. the negative impact of human activity on the natural environment.
An important element for the maintenance of green areas in cities may be the use of rainwater and snowmelt collected in multi-functional tanks for the alimentation of green areas, implemented in a cyclic “smart way”. The city should become like a sponge – naturally absorbing rainwater the moment it appears and giving it back later for various purposes for the benefit of vegetation and people.
HYDROZONE retention tanks are one of these smart solutions that are ideal for use in tight urban environments thanks to their compact, modular design. The use of pre-treatment systems offers a wide range of possibilities not only for retention, but also for the use of the stored water. This has a significant impact on stopping urban drying out, i.e. reducing surface water run-off in order to protect and restore water resources.