Dry‐stone wall terrace monitoring and modelling

Abstract

Dry‐stone wall agricultural terraces are widespread all over the world and represent an effective retaining structure for farming purposes. However, dry‐stone walls can be subjected to degradation and damages, with complex and expensive maintenance. Such high costs are the most relevant drivers of land abandonment in many agricultural areas of Europe and of other continents, resulting in a progressive loss of cultivable surface, cultural heritages, and landscape traditional elements. Therefore, a more effective and efficient management of these systems is needed. As a contribution, in the present paper, an innovative modelling approach system is proposed. The presented model is able to describe hydrological processes on a terraced slope and to analyze the destabilizing pressures acting on the retaining dry‐stone walls in the most critical portion of each terrace. The model structure is based on the results of multidisciplinary field monitoring campaigns on water circulation in terraced landscapes carried out on a terraced vineyard (Lamole, Tuscany, Italy). A monitoring station was set up on a recently reconstructed dry‐stone wall, to measure the parameters influencing the pressures acting on the retaining structure. The results show a good capability of the model to predict the distribution and intensity of stresses on the instrumented dry‐stone wall over time and space. Such stresses were related to the earth pressure and to hydrostatic pressures (water accumulation), without the occurrence of soil saturation. Detecting the most failure‐prone portions of a terraced system, this approach can support landowners and land planners in managing these complex and fragile environments.

Agricultural Terraces Special Issue Preface

“…Groundwater rise did not occur, as observed in other terraced sites. However, infiltrated water accumulated behind the dry-stone walls increased the pore water pressure and causing wall instability Preti, Errico, Caruso, Dani, and Guastini (2018). described an innovative modelling approach for the monitoring of dry-stone wall terraces.…”

A critical analysis of Vacca, A., Aru, F., and Ollesch, G. (2017). Short‐term impact of coppice management on soil in a Quercus ilex L. Stand in Sardinia. Land Degradation & Development, 28(2), 553–565

“…However, the infiltration values presented by the authors are particularly high (184 ÷ 7,920 mm hr −1 and 377 ÷ 7,920 mm hr −1 for the S'Isteri and Su Caraviu stands, respectively) compared with the reference values for similar soils (Bradford, Ferris, & Remley, 1987;Azooz & Arshad, 1996;Preti, Errico, Caruso, Dani, & Guastini, 2018; Minnesota Stormwater Manual; Sacramento County Code). In the north of Sardinia, in a sandy loam soil covered by 2-to 4-m high maquis, Pirastru, Castellini, Giadrossich, and Niedda (2013) found a mean saturated hydraulic conductivity of 455 mm hr −1 at 10 cm depth.…”

Terraced Landscapes and Hydrogeological Risk. Effects of Land Abandonment in Cinque Terre (Italy) during Severe Rainfall Events

“…Recent publications discovered that the beneficial effects of terracing are more evident where the well-maintained surfaces are more extensive, and the farming system is more complex [12,13]. In fact, the main factor that triggers landslides seems to be the lack of runoff control which, even in terraced woodlands, is concentrated in areas where the saturation of surface soil layers leads to failure [11,40,41]. For such situations, the presence of abandoned and partially destroyed terraces under tree cover can constitute an aggravating factor of instability [42].…”