Airflow dynamics, vegetation and aeolian erosive processes in a shadow zone leeward of a resort in an arid transgressive dune system

Abstract

Airflow dynamics, vegetation and aeolian erosive processes in a shadow zone leeward of a resort in an arid transgressive dune system ABSTRACT Structures and infrastructures can modify aeolian sedimentary dynamics as has occurred in the arid transgressive dunefield of Maspalomas (Gran Canaria, Canary Islands), where an aeolian shadow zone has been formed leeward of a tourist resort (Playa del Inglés). The aim of this paper is to examine and statistically analyse the influences of vegetation and topography on wind flow across this shadow zone. An experiment was carried out in March 2017, collecting wind speed and direction from 5 transects with anemometers at 0.40 m height. Simultaneously, a drone flight was carried out, from which an orthophoto and digital elevation and surface models (DEM and DSM)were obtained. Distance from the resort, and the presence of vegetation were found to influence transects dominated by erosional processes. Transects that do not display erosional processes were primarily affected by the presence of vegetation. The local wind field changes at a similar distance across the transects downwind from the resorts indicating an acceleration or reattachment of the wind at this distance downwind. The vegetation role in this aeolian shadow zone could be a key to the future evolution of the area resulting in either further stabilization, or alternatively, the continued deflation of the area.

A DIY Low-Cost Wireless Wind Data Acquisition System Used to Study an Arid Coastal Foredune

“…There were no communication problems between the base station and the wind sensing devices during the sessions. In fact, thanks to the reach of XBE PRO S1 802.15.4 modules, the data acquisition system has already been deployed to study bigger areas, specifically in an experimental study covering an area of 27.76 ha, the results of which have been published in [82]. Moreover, as mentioned in the previous paragraph, if required, the data acquisition system can be configured using a mesh network topology, which will enable experimental deployments with greater reach and hence the coverage of more extensive areas.…”

“…A more cost-effective approach to such environmental studies is of general interest, but is especially true for developing countries with less research funding [83]. In a subsequent experimental work [82], not described in this manuscript, the data acquisition system was again successfully deployed covering a larger extension. On this occasion, it was used to study the influence of tourist constructions on the limits of the same dune field as they significantly affect wind behavior and, consequently, sand transportation and dune formation.…”

“…In addition, the precision of the topographic data derived from the drone flight was tested using ground data collected on-site with a topographic total station. Further details can be found in [82].…”

Biogeomorphological responses of nebkhas to historical long-term land uses in an arid coastal aeolian sedimentary system

“…Meanwhile, more recent land uses and the abandonment of traditional ones have led to the stabilization of sand sheets as the result of the plant recolonization processes (Tsoar and Blumberg, 2002;Kutiel et al, 2004;Marrero-Rodríguez et al, 2020). In other studies, recent land uses, associated especially with urban-tourism development, have been attributed with causing alterations to wind dynamics and a lower sand input, with a consequent reduction or disappearance of mobile dunes or an increase in deflation surfaces and stabilized dunes (Hernández-Calvento et al, 2014;Smith et al, 2017;García-Romero et al, 2016, 2019a, 2019b).…”

“…The coastal aeolian systems of the planet have been exposed to a process of anthropic degradation related to traditional activities such as grazing, obtaining firewood or agriculture (Tsoar and Blumberg, 2002;Kutiel et al, 2004;Levin and Ben-Dor, 2004;Provoost et al, 2011) and to recent uses such as aggregate extraction, the construction of urbanizations and tourist infrastructure, and recreational uses (Nordstrom and McCluskey, 1985;Nordstrom, 1994;Nordstrom, 2004;Smith et al, 2017;García-Romero et al, 2019b;Delgado-Fernández et al, 2019). All these uses have induced environmental transformations whose consequences have been, among others, changes in landforms and aeolian sedimentary activity (dune stabilization) (Cabrera- Vega et al, 2013;Hernández-Cordero et al, 2018), reductions of pioneer plants in mobile dunes and species richness (Kutiel et al, 1999;Curr et al, 2000;Dolnik et al, 2011;Faggi and Dadon, 2011), sediment remobilization (Arens et al, 2013), accelerated erosion processes (García-Romero et al, 2016;García-Romero et al, 2019b), alteration of the direction and speed of wind flow (Hernández-Calvento et al, 2014;Smith et al, 2017;García-Romero et al, 2019a), and on occasions surface reduction (Hernández-Cordero et al, 2018). It can be argued, therefore, that most of the surviving ecosystems are an expression of their resilience and that their evolution after the land uses is not restricted to the recovery of the original functions and characteristics but to the adaptation and reorganization of the components of the landscape to the post-disturbance situation (Kombiadou et al, 2019).…”