Recognition and mapping of lacustrine relict coastal features using high resolution aerial photographs and LiDAR data

Water level control on coastal landform distribution and associated processes in a highly fluctuating shallow lake (Gallocanta Lake, NE Spain)

“…All the lacustrine terraces surrounding Gallocanta Lake, as well as other old beach ridges and lunettes along the SE margin of the depression, are indicative of the progressive desiccation of the lake. This trend started in the Late Pleistocene, when the lake reached its maximum extension, a height of 1005 m a.s.l., and was 13‐m deep (after discounting the thickness of the lacustrine sediments lying under the present lake bed; Castañeda & Gracia, 2017). Subsequently, a long period of fluctuations (Gracia et al, 2021) led to the present situation of prevailing low levels.…”

“…The flooded surface extended up to the 993.25 m a.s.l. contour line, as extracted from the LiDAR‐derived digital elevation model (DEM; Castañeda & Gracia, 2017). In this work, this height is considered to be the maximum water level in order to apply a wind‐induced circulation model to the lake, whereas the lowest level (reference – 0 level) is considered to be equivalent to 991.2 m a.s.l., the height of the lakebed.…”

“…Its shores present a set of coastal forms typical of very dynamic environments, with beaches, spits, barrier islands, lagoons and deltas (Castañeda et al, 2020). However, the distribution of these coastal forms seems to be controlled by the different water levels found in the lake in recent times (Castañeda & Gracia, 2017). The aim of the present work is to compare the most frequent lake water levels with the distribution of coastal forms around the lake in order to identify which are the most active, the hydrodynamic conditions responsible for their activation and the present erosional/ progradational trends associated with them.…”

Geomorphological control of habitat distribution in an intermittent shallow saline lake, Gallocanta Lake, NE Spain

“…The median values of the morphodynamic units configure a clear sequence of littoral lacustrine processes, from those related to present-day dynamics (GeoUnit 1) to relict forms (GeoUnits 11 and 12). On average, the uppermost (oldest) geomorphological units are roughly 3 metres above the lakebed, illustrating the overall flatness of the lake environs and the advantages of addressing the geomorphology based on a detailed digital elevation model (Castañeda and Gracia, 2017). The median values of most units overlap with the interquartile range of the succeeding unit indicating the difficulty of easily discriminating units based solely on topography over such a flat relief.…”

“…From a sedimentary perspective, they represent former perilacustrine plains in sedimentary environments (commonly beaches) active during past periods of the lake's history. Associated deposits, accessible in quarries and pits dug into the different terrace levels, show typical coastal, mainly beach deposits (Gracia, 1995;Castañeda and Gracia, 2017).…”