Inka Hydraulic Engineering at the Tipon Royal Compound (Peru)

The Inka site of Tipon had many unique hydraulic engineering features that have modern hydraulic theory counterparts. For example, the Tipon channel system providing water to the Principal Fountain had a channel contraction inducing critical flow as determined by CFD analysis- this feature designed to induce flow stability and preserve the aesthetic display of the downstream Waterfall. The Main Aqueduct channel sourced by the Pukara River had a given flow rate to limit channel overbank spillage induced by a hydraulic jump at the steep-mild slope transition channel location as determined by use of modern CFD methods- this flow rate corresponds to the duplication of the actual flow rate used in the modern restoration using flow blockage plates placed in the channel to limit over-bank spillage. Additional hydraulic features governing the water supply to agricultural terraces for specialty crops constitute further sophisticated water management control systems discussed in detail in the text.

Rethinking Terraces and Dry-Stone Walls in the Alps for Sustainable Development: The Case of Mombarone/Alto Eporediese in Piedmont Region (Italy)

Nowadays, agricultural terraces and dry-stone walls have become protagonists of a territorial “rebirth” through a process of resemantization that recognizes them as a local resource. In relation to this focus, this article deals with a specific case study located in the Mombarone/Alto Eporediese area, in the northern part of the Piedmont Region (Italy), where terraced landscapes represent a unique environmental heritage, which has been partially abandoned. In this article, we illustrate the process carried out by local institutions in the Strategic Plan “Dalla Dora al Mombarone” and by the European Project Interreg Alcotra “Vi.A.- Route of Alpine Vineyards” which have involved many stakeholders of the local communities. In particular, starting from the results obtained by the engagement of social and territorial scientists in the projects mentioned above, we examined how terraces can support the reconstruction of a specific sense of place by the local community and the implementation of a sustainable development model through innovative solutions that go beyond the tradition in a frame of a green, soft and inclusive economy.

Role of Agricultural Terraces in Flood and Soil Erosion Risks Control in the High Atlas Mountains of Morocco

Terraced farming play several roles, from improving ecosystem services to enhancing associated population livelihoods. In this study, we were interested in evaluating the roles of mountain terraces in controlling floods and erosion risks, in particular in the Ourika watershed, located in the High Atlas mountains of Morocco. Rainfall simulation tests were conducted to measure infiltration, runoff and initial abstraction, while the Cesium-137 isotope technique was used to quantify soil loss. The results highlighted high infiltration for dense forests (78.00 ± 2.65 mm/h) and low for rangelands (27.12 ± 2.82 mm/h). For terraces, infiltration was found to be about 70.36 ± 0.56 mm/h, confirming the role of terraces in promoting infiltration. The runoff coefficient obtained was lowest for dense forests, followed by cultivated terraces, and highest for rangelands (62.71 ± 3.51). Thus, outside dense forests, infiltration and runoff were significantly very high and low, respectively, for agricultural terraces compared to other land use. The assessment of soil erosion rates showed a significant soil loss for rangelands compared to the agricultural terraces, further underlining the role of terraces in soil conservation. Terraces in the Ourika watershed, by increasing water infiltration, reduce the rate of surface runoff, and consequently, flood risks and soil degradation.

From section to landscape(s) : reconstructions of environmental and landscape changes since the 7th millennium BCE around the site of Wakarida (Ethiopia) using chronostratigraphy

Geoscience is a very useful tool for approaching the relationships between societies and their environment. However, it is not always possible to apply very advanced techniques or to perform a large number of analyses. This paper aims to show that chronostratigraphic studies can provide satisfying answers to the main geoarchaeological questions, “only” using sedimentological, stratigraphic and chronological analyses. The objective here is to move from the study of stratigraphic sections, uncovered in valley bottoms filled by sedimentary deposits, to the reconstruction of landscape and environmental changes, in connection with the archaeological site of Wakarida (northern Tigray, Ethiopia). The actual landscape around Wakarida is made of steeply sloping valleys, filled with accumulations of sediments several meters thick. These deposits are cultivated by the inhabitants thanks to the building of agricultural terraces. Archaeological excavations have uncovered an urban settlement in Wakarida, dating between the classical Aksumite (150-400/450 CE) and the post-Aksumite periods (800/850 CE), and more ancient (pre- and proto-Aksumite periods) structures in the area under survey. Such structures raise the question of the interactions of the populations with their environment through time. More precisely, they question their role in the deposition of the sediments. To tackle these questions, a method based on a combination of field work, sedimentological analyses and dating has been employed. Such a chronostratigraphic study made it possible to identify several phases in the establishment of the current landscapes around the Wakarida site. During Early Holocene, valleys were gradually filled by alluvial and/or colluvial processes of low energy. During Middle Holocene, ablation processes alternated with deposition, showing the effects of climatic and possible anthropogenic processes. From the 1st millennium BCE onwards, the impact of population on their environment is visible, but especially around the 14th – 17th centuries. An important part of these conclusions is based on the attention given to chronological inversions and the fact that these dates, "false" at first glance, reveal ablation and deposition phases within sedimentary cascades. It therefore seems important, from a methodological point of view, not to reject these dates a priori, but to consider them by giving them their full place in the chronostratigraphic reflection.

The Terraces of the Anti-Atlas: From Abandonment to the Risk of Degradation of a Landscape Heritage

The Anti-Atlas is subject to an intense rural exodus. The agricultural terraces built for several centuries have been abandoned. They are gradually deteriorating. The risks of runoff and erosion are becoming significant. The objective was to study the effect of the abandonment of terraces on the risks of runoff and erosion in the territory of two villages, Tizerkine and Timzemzit. After the characterization of the soil surface conditions, the extent of erosion and the risk of runoff were qualified according to the age of abandonment. Erosion was assessed by estimating the “soil surface factor” (PAP/CAR method) and infiltration by the double ring method. The abandonment of the terraces has led to a reduction in the plant cover of the soil surface and its opening and to enhancing its compaction. The risk of runoff is high. A year of abandonment reduced the infiltration from 301.8 mm/h (SD: 105.8 mm/h) to 129.6 mm/h (SD: 28.9 mm/h). Furthermore, 5 years of abandonment reduced it to 62.9 mm/h (SD: 14.9 mm/h). The walls of the terraces are gradually being destroyed with an increasing age of abandonment. More than half (57%) of the terraced slope surface has suffered moderate to high water erosion. More than 11% of the surfaces are severely degraded after 20 years of abandonment. The heritage made up of these managed slopes is being lost. Particular attention must be paid to these landscapes in order to better rehabilitate and develop them.