Environmental evolution of abandoned terraces

The bands as a modification of the natural landscape

The agricultural terraces – which here you will hear called “bands” – represent a significant alteration of the environmental characteristics of the slopes, creating a new topography and modifying the hydrographic network. The terraced soils that characterize the Ligurian landscape are artificial, the result of “rehabilitations” often created with material brought from other areas. These interventions give rise to new geomorphological and hydrological models that require constant maintenance.

The hydrographic effects of terraced slopes

From a topographic point of view, terraces in a good state of conservation can stabilize the effects of precipitation on the soil, reducing the surface flow of water and slowing down erosion thanks to the reduction of slopes, which facilitates better infiltration of water into depth. However, terracing also increases the importance of processes occurring underground, leading to management problems. Among these are:

a) the progressive removal of the finest material along the infiltration and filtration paths towards the drainage structure of the wall,

b) the increase in water contents and pore pressures in the soils behind the wall.

The vulnerability of abandoned terraced slopes

Once abandoned, the terraced slopes tend to restore their original slopes through the reactivation of gravitational processes: landslides. When terraces are abandoned, the slopes are unlikely to return to ecological conditions similar to those before their construction. The greater the transformation necessary to adapt them to agricultural and building use, the more fragile and vulnerable they become once abandoned. When control over the stability of the buildings and the functioning of the water evacuation systems is lost, the vulnerability of the terraces increases, as does the associated risk. The intensity and speed of these processes are influenced by the environmental and historical specificities of each slope.

The process of decay of dry stone walls

In the first phases of slow evolution, phenomena such as the undermining of the foot or the bulging of dry stone walls are observed, caused by the pushing action of the water and spontaneous vegetation. This can lead to slope sliding, supported by surface runoff. The initial detachment niches can cause chain effects in the underlying areas, with a progressive increase in load and, through regressive erosion, on the areas above.

Sources

Bonardi L., “Geografia e storia dei terrazzamenti agrari”, in Bonardi L., Varotto M. (a c. di), “Paesaggi terrazzati d’Italia”, Milano, FrancoAngeli, 2016

Terranova R.,”L’abbandono dei versanti montani terrazzati e i dissesti geomorfologici: una grave perdita di valori ambientali di grande pregio”, in Terranova R., Brandolini P., Fipro M. (a c. di), “La valorizzazione turistica dello spazio fisico come via alla salvaguardia ambientale”, Bologna, PÁTRON Editore, 2005

Percorsi trekking e bici che potrebbero interessarti

Itinerari di diversa durata e adatti a ogni gusto e livello di preparazione, alla scoperta dei luoghi e dei panorami più belli e suggestivi del Tigullio ligure.

Sorry, no posts matched your criteria.