Stop 11 – Reclamation: good water management

Difficult water management
Since ancient times humans have been building residential settlements on uplands, avoiding marshy areas due to the hygienic-sanitary and logistical problems posed by stagnant water
The increasing “hunger” for land has led to hydraulic reclamations aimed at removing excess water in order to facilitate the development of settlements and agriculture. Over time, the concept of reclamation has been expanded to include any intervention carried out to protect the land such as flood protection, management of mountain streams, reforestation, roads, etc.

Types of hydraulic remediation

  • Land drainage: the land needing reclaiming is located at a higher altitude than the point of delivery and disposal of the collected water
  • Land reclamation by pumping stations: the areas to be drained are at a lower altitude, the collected water is lifted by water-pumping plants
  • Aggradation: an alternative strategy to land reclamation, feasible in areas close to waterways that are rich in suspended solid material. Silty waters are conveyed to the areas to be reclaimed where the sediments are deposited, and the increase in the level of the soil enables the excess water to flow out

Land reclamation has been adopted in the area where you are now
Whatever the type of remediation adopted, a dense network of canals is essential (Photo 3). They need to collect and remove the water from the wet areas and are designed to create and maintain a drained soil layer that has been reclaimed, i.e. the difference in height between the ground surface and the level of water in the drainage ditches. The drained soil layer, in turn, needs to take into account the unsaturated zone, the minimum layer of soil necessary for the development of crops (50-60 cm for natural meadows and winter cereals, 100 cm for woody crops)

Current issues
The increasing surface waterproofing of soils and aggressiveness of the rainfall reduce the infiltration of rainwater into the soil and hinder the regulation of water.
Detention basins enable excess water to be disposed of without changing the size of the surface water network. These are cradles designed to temporarily subtract excess flow rates until normal surface run-off conditions are restored.
These basins also serve other functions:

  • recharge of aquifers
  • phytodepuration (Photo 4), thanks to the presence of hydrophilic vegetation which reduces the quantity of nutrients and sediments, contributing to increasing the animal and plant biodiversity
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