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Morphogenetic landforms
Published in Richard J. Chorley, Stanley A. Schumm, David E. Sugden, Geomorphology, 2019
Richard J. Chorley, Stanley A. Schumm, David E. Sugden
Parallel slope development and the consequent production of simple skirting soft-rock pediments can take place in shales and other fine-grained rocks of low resistance when they are capped by rock which is resistant to surface stream action (e.g. sandstone or permeable gravel) or where the shale tends to weather seasonally into a fragmental layer over the whole slope (e.g. due to the swelling and cracking of sodium-rich clay minerals or to frost action) and to be completely removed by surface runoff during the rainy season. Where shales which are susceptible to stream incision are exposed by the stripping off of a more-resistant cover (e.g. the Wingate Sandstone from the Chinle Shales which form the Painted Desert) or near the base of a retreating cliff (see Figure 11.35B and C), then badlands are formed in areas of sparse vegetation. Badlands are so called because their very high drainage densities and steep slopes make them very difficult to traverse. Geomorphologists have shown considerable interest in badlands because they provide a model of arid erosion, and because erosion is rapid. During a period of a few years information can be collected on the manner and rate of hillslope retreat (see Chapter 11), as well as on alluvial fan and pediment formation. The experimental studies discussed in Chapter 13 are in reality a study of badland processes in the laboratory.
Gulley Control
Published in Herman J. Finkel, Moshe Finkel, Ze’ev Naveh, Semiarid Soil and Water Conservation, 1986
The gulley is the most obvious and spectacular form of soil erosion as it causes large, unsightly gashes in the landscape. Deep gullies which spread back to the watershed divide can destroy an entire area and are the ultimate form of soil erosion known as “badlands”. Not all gullies are so ominous, but they are insidious in their growth potential, and hence must be brought under control in the earliest possible stages. They appear in several forms, each of which has different characteristics and requires different methods of control. The two principal types are the so-called V and U gullies.
The Basilicata region (Southern Italy): a natural and ‘human-built’ open-air laboratory for manifold studies. Research trends over the last 24 years (1994–2017)
Published in Geomatics, Natural Hazards and Risk, 2019
Fabrizio Terenzio Gizzi, Monica Proto, Maria Rosaria Potenza
Basilicata is one of the Italian regions most prone to hydrogeological instability, in which nearly 50% of the towns are classified as exposed at high risk of landslides or floods (e.g. Clarke and Rendell 2006; Di Maio et al. 2010; Lazzari 2011). The area affected by flood risk is 260 km2 wide (2.6% of the whole territory) and mainly includes the hilly areas and the coastal belt, which are exploited in agriculture, the main regional economic source (e.g. Piccarreta et al. 2013). Moreover, the nature of cropping terrains coupled with the climate dynamics have brought several inner areas to desertification, due to the widespread forms of land degradation (badlands) including rills, gullies, debris flows and loss of soil fertility (e.g. Piccarreta et al. 2006). This is probably due to the type of soil and to the deforestation, necessary to make room for pastures and the growing of cereals.