Parametric Terracing as Optimization of Controlled Slope Intervention

Abstract

With the introduction of mechanization in agriculture, the area of terraced slopes has increased. However, in most cases, the planning of terracing in practice remains experience-based, which is no longer effective from an agricultural, geological, and hydrological point of view. The usual method of building terraces, especially terraces with earth risers, is therefore outdated, and a new method must be found for planning and building terraced areas. In addition to geographical information system (GIS) tools, parametric design tools for planning terraced landscapes are now available. Based on the design approaches for a selected plot in the Gorizia Hills in Slovenia, where we used a trial-and-error method, we improved previous results by defining a model using a computer algorithm that generates a terraced landscape on a selected slope depending on various input parameters such as the height of the terrace slope, the inclination of the terrace slope, the width of the terrace platform, and the number of terraces. For the definition of the algorithm we used the visual program tool Grasshopper. By changing the values of the input data parameters, the algorithm was able to present combinatorial simulations through a variety of different solutions with all the corresponding statistics. With such results it is much easier to make a conscious decision on which combination of parameters is optimal to prevent landslides, plan adequate drainage, and control soil movements when building terraces. The controlled slope intervention is further optimized by the introduction of a usage index (Tx), defined as the quotient of the sum of all flat areas (terrace platforms) and the total area of the plot.

What is the extension of bench terrace construction for forest plantations? The case of North Central Portugal

“…According to Hudson (1981), the slope angle exceeding 30° is a key limiting factor for the construction of bench terraces. Even in stable and deep soils, higher slope angles increase the water pressure in the soil pores and might initiate the riser collapse (Berčič & Ažman‐Momirski, 2020). Bugenimana et al (2019) found in Rwanda that most of the terraced sites do not follow the technical guidelines, whereas many zones were built with slope angles lower or higher than standards and claim that such circumstances have increased the risks of landslide and erosion with no clear advantage for soil erosion mitigation and crop production.…”

Terraced Landscapes and Hydrological-Geological Hazards: Innovative Approaches and Future Perspectives

“…Berčič, and Ažman-Momirski [16] developed an innovative parametric design procedure for planning the design of terraced landscapes, with a case study in Slovenia, implemented in the "Grasshopper" plugin in Rhino 3D. The approach proposed was proven to be effective in optimizing the design process of new terraced systems.…”

“…Such kinds of research efforts could be considered of particular interest, since, while most of the "historical" terraced landscapes were created a long time ago, they offer the possibility of analyzing the different parts of the terracing implementation, highlighting possible errors, their consequences, but also innovative design methodologies. Some of the case studies focused on issues related to terrace abandonment (Figure 3) [13,15,17,19,20], which represent an issue at the global scale [1,6,7], while others focused instead on new terrace system implementation [14,16]. Such kinds of research efforts could be considered of particular interest, since, while most of the "historical" terraced landscapes were created a long time ago, they offer the possibility of analyzing the different parts of the terracing implementation, highlighting possible errors, their consequences, but also innovative design methodologies.…”