Abstract
AbstractPredicting the location of gully heads in various environments is an important step towards predicting gully erosion rates. So far, field data collection and modelling of topographic thresholds for gully head development has mainly focused on gullies that formed in forested areas, rangelands, pastures and cropland. Such information for gullies in badlands however is very scarce. Therefore, this paper aims to extend the database on gully head topographical thresholds through data collection in a badland area and to improve the prediction of gully heads forming at sites with a very low erosion resistance value. For this, we chose a badland site located in central Italy that is characterized by biancana forms and both active and dormant gullies. The definition of the conditions under which present‐day gully heads developed allowed a better modelling of the gully head threshold equation, with modification of a previous model and the exemplification of how to use the updated model. The model shows that the resistance to gully head retreat depends on slope gradient and drainage area at gully heads, land use at the moment of gully development (as numerically expressed using parameters derived from the Runoff Curve Number method), surface rock fragment cover, presence of joints, pipes, and factors/processes affecting detachment rate. This study attempted to better understand environmental conditions that control the development of gully heads in badlands through a combination of field data collection of gully heads, an analysis of land use changes over 10 centuries, focusing on the period 1820–2005, and land use management through repeat photography and a critical examination of historical documents. © 2018 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd.
Highlights
Soil erosion processes are major contributors to land degradation and landscape transformations (Lal, 2001; Reusser et al, 2015)
Predicting where and when gully heads will develop on hillslopes under changing environmental conditions, and how fast and up-to-where in the landscape these heads will retreat, is a fundamental step to characterize the geomorphological processes acting on a slope and their dynamics
This paper aims: (1) to extend the database on gully head thresholds through field observations on gully head characteristics in a badland area; (2) to predict gully heads forming at sites with a very low resistance value and discuss how to model this; (3) to discuss and clarify the introduction of a land use and vegetation factor into the threshold equation; and (4) to evaluate the importance of other factors, which are presently grouped under the factor c in the threshold equation
Summary
Soil erosion processes are major contributors to land degradation and landscape transformations (Lal, 2001; Reusser et al, 2015). Most of the time, gullying is triggered by human-related complex processes acting over centuries such as overgrazing, over-cropping, and urbanization (Poesen et al, 2003). This is evident in the Mediterranean region where gully erosion is often associated with the long-term history of deforestation induced by political and cultural changes, and pressures exerted by agriculture and cattle breeding (García-Ruiz, 2010). Predicting where and when gully heads will develop on hillslopes under changing environmental conditions (i.e. climate and land use), and how fast and up-to-where in the landscape these heads will retreat, is a fundamental step to characterize the geomorphological processes acting on a slope and their dynamics
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
