Geomorphology of the Tafilalt Basin, South-East Morocco – implications for fluvial–aeolian dynamics and wind regimes

Herzog, Manuel; Henselowsky, Felix; Bubenzer, Olaf

doi:10.1080/17445647.2021.1990805

Cited by 6 publications

(6 citation statements)

References 35 publications

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“…The surrounding higher flatlands (hamada) are predominantly formed of Neogene and Cretaceous sediments. Quaternary deposits exist in the form of widespread alluvial fans of the Oued Rheris and Ziz, with their watersheds as well as pediments and larger sand/dune field deposits (Barczuk et al, 2008; Herzog et al, 2021; Robert‐Charrue, 2007). The basin floor is flat overall, with a slight inclination to the south.…”

Section: Study Areamentioning

confidence: 99%

“…From a geomorphological point of view, the basin, except the erg, is strongly influenced by the ephemeral river system of Oued Rheris and Ziz, originating in the Atlas Mountains and watering the Tafilalt oases around Rissani. Both river systems desiccate in the central basin near Merzouga and further south in Algeria (Herzog et al, 2021).…”

Section: Study Areamentioning

confidence: 99%

“…The sediments of the studied star dune are built up by well‐sorted grain sizes between fine and medium sands (Puy et al, 2018), mostly consisting of quartz (Barczuk et al, 2008). The dune covers an area of around 50 ha and is assumed to have formed under bimodal to multimodal wind systems (Herzog et al, 2021; Puy et al, 2018).…”

Section: Study Areamentioning

confidence: 99%

“…The evolution and dynamics of star dunes in sand seas (ergs) around the globe are, to date, only partially understood (Goudie et al, 2021). Published studies concerning star dune generation and evolution so far focus on larger regional wind systems with a high directional variability depending on seasonal changes (Herzog et al, 2021;Lancaster, 1989aLancaster, , 2005Tsoar, 2001;Zhang et al, 2012). The location of star dunes seems to be bound to depositional centres (Dong et al, 2004;Mainguet & Callot, 1978;Zhang et al, 2016) and the star dunes, once established, tend to add sand to their bulk and act as depositional centres themselves.…”

Section: Introductionmentioning

confidence: 99%

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Capturing complex star dune dynamics—repeated highly accurate surveys combining multitemporal 3D topographic measurements and local wind data

Herzog

Anders

Höfle

et al. 2022

Earth Surf Processes Landf

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Morphologies of highly complex star dunes are the result of aeolian dynamics in past and present times. These dynamics reflect climatic conditions and associated forces like sediment availability and vegetation cover, as well as feedbacks with adjacent environments. However, an understanding of aeolian dynamics on star dune morphometries is still lacking sufficient detail, and their influence on formation and evolution remains unclear. We therefore investigate the dynamics of a complex star dune (Erg Chebbi, Morocco) by analysing wind measurements compared to morphometric changes derived from multitemporal high-accuracy 3D observations during two surveys (October 2018 and February 2020). Using real-time kinematic global navigation satellite system (RTK-GNSS) measurements and terrestrial laser scanning (TLS), the reaction of a star dune surface to an observed constant unimodal sand-moving wind is presented. TLS point clouds are used for morphometric analysis as well as direct surface change analysis, which relates to sand transport. RTK-GNSS measurements enable the assessment of horizontal crest movement. Observed surface changes lead to the identification of an overall shielding effect, resulting in sand accumulation mainly on windward slopes. Our results point to a self-sustained dune growth, whichhas not yet been described in such spatial detail. Steep slopes, often found on star dunes around the globe, seem to partly hinder upslope sand transport. Though a comparatively short observation period, we therefore hypothesize that, besides wind intensity alone, slope angles are more decisive for sand transport than previously assumed. Our methodological approach of combining meteorological data and highresolution multitemporal 3D elevation models can be used for monitoring all dune forms and contributes to a general understanding of dune dynamics and evolution.

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Section: Study Areamentioning

confidence: 99%

Section: Study Areamentioning

confidence: 99%

Section: Study Areamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Capturing complex star dune dynamics—repeated highly accurate surveys combining multitemporal 3D topographic measurements and local wind data

Herzog

Anders

Höfle

et al. 2022

Earth Surf Processes Landf

Self Cite

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“…This variation in altitude contributes as well to a diversity of climate from north to south. Precipitations in the province are irregular in time and space from more than 250 mm in the highlands (High Atlas) to 130 mm near the city of Errachidia to less than 75 mm in the desert (Tafilalet plain) (HCP, 2018), which indicates hyper-arid climate conditions in Tafilalet Basin (Herzog et al, 2021). More precisely, the annual rainfall is 70 mm at Erfoud (the south) and 290 mm at Imilchil (the northern area) while the temperatures range from −5 °C to 40 °C (Ben Salem et al, 2011).…”

Section: Study Areamentioning

confidence: 99%

Exploring the land use and land cover change in the period 2005–2020 in the province of Errachidia, the pre-sahara of Morocco

et al. 2022

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The study investigates the land use and land cover (LULC) in Errachidia province (Pre-Saharan of Morocco) in the period 2005–2020. To this end, remote sensing (RS) tools such as LULC, the normalized difference vegetation index (NDVI), the normalized difference water index (NDWI), the Enhanced Vegetation Index (EVI), Gravity Recovery and Climate Experiment (GRACE) satellite data, and precipitations were processed and combined. The monitoring of LULC over this period reveals different changes in this area. Generally, for water bodies, two trends can be observed, an increasing trend since 2006 and a decreasing trend from 2011 to the present. However, an increasing trend was recorded for the urban-and-built-up-lands and the grasslands categories. NDVI, NDWI, and EVI showed three major peaks recorded in the same periods (in 2007, 2009, and 2015). In terms of water storage, three phases were found. The first depicted the lowest groundwater quantities with a decreasing trend, which corresponds to a period of drought and/or human pressure. The second phase, the most important that recorded the greatest storage of water while the third phase corresponds to low storage with a decreasing trend. LULC of croplands reveals a slightly increasing trend from 2012 to 2020, which shows an orientation to an extension of crops mainly of date palm encouraged by government programs. A strong correlation between the seasonal NDVI and water storage using GRACE-Data for the period was found. In the end, recommendations on the adaptation to CC were proposed. The findings demonstrate that RS techniques are useful tools to detect hydrological droughts, observe, and conserve land resources. In arid areas such as Errachidia, the solution lies in rationalizing the use of water resources protecting them from uncontrolled anthropogenic events, which may alleviate the pressure. To support local sustainable development, environmental scientists and decision-makers may use the outputs of this study.

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The Development and Characteristics of Sand Seas in the Central Sahara

Knight,

Merlo

2023

World Geomorphological Landscapes

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Geomorphology of the Tafilalt Basin, South-East Morocco – implications for fluvial–aeolian dynamics and wind regimes

Cited by 6 publications

References 35 publications

Capturing complex star dune dynamics—repeated highly accurate surveys combining multitemporal 3D topographic measurements and local wind data

Capturing complex star dune dynamics—repeated highly accurate surveys combining multitemporal 3D topographic measurements and local wind data

Exploring the land use and land cover change in the period 2005–2020 in the province of Errachidia, the pre-sahara of Morocco

The Development and Characteristics of Sand Seas in the Central Sahara

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