Geomorphology of the mouth of the Arosa estuary (Coruña-Pontevedra, Spain)

Abstract

This paper presents a geomorphological analysis of the littoral zone of the Arosa-Pontevedra estuary mouth and identifies geomorphological units and categorizes them into morphogenetic systems. The different morphogenetic systems are used to establish a comprehensive evolutionary analysis, contrasting the depositional systems found in the continental littoral zone with the marine erosional systems ('rasas'). The compiled cartography groups the geomorphological units into the following: the lithoestructural morphogenetic system with large-scale forms (domes, inselbergs, residual relief, etc.) and small-scale forms (gnammas, tafoni, channels, etc.); the littoral morphogenetic system comprised of marine (marine terraces, beaches, tidal bars, tombolos and coastal arrows), transition (marshes, lagoons and fan deltas) and eolian (dune systems) settings; the fluvial morphogenetic system with channelled (alluvial, flood plain and river terraces), transition (alluvial fans and alluvial cones) and sheet flood (pediments and glacis) systems; the gravitational morphogenetic system (colluvium); and the alteration morphogenetic system (sand-alteration). ARTICLE HISTORY

Landscape Analysis and Coastal Planning: Ría de Arosa (Pontevedra, Spain)

“…The oceanic effect is the main factor influencing mild temperatures and abundant precipitation. An average annual precipitation of approximately 1455 mm is recorded, with a summer average temperature of 19.3 • C and 9 • C in winter [25].…”

“…These units are situated atop the Variscan basement. The structural conditions and transitional nature of the area allow for the development of various morphogenetic systems, with lithological characteristics shaping the distinctive and specific relief of the Galician coastal zone, including the Ría de Arosa, and influencing the area's morphogenesis [15].…”

“…The term "ria" refers to an estuary generated by an ancient coastal river valley that has been flooded by the sea during the Quaternary period. Its origin is linked to fracture systems that describe a block relief (horst and graben) with submerged and emerged areas [13][14][15]. The emerged coastal areas present a multitude of structures associated with various morphogenetic systems (coastal, lithostructural, fluvial...) because of the number of processes that have acted on the area.…”

“…The higher the sinuosity, the greater the sensitivity to landscape disturbance of the unit (see Table 15). Relating all the factors, the mapping of intrinsic landscape fragility (ILF) is obtained using Equation (4) [10,15]: ILF = Geomorphological fragility mapping (slopes + orientation) + Area factor of landscape units + ∑ Vegetation fragility factors (4)…”

Analysis of the Risk of Coastal Flooding Due to Rising Sea Levels in Ría of Arosa (Pontevedra, Spain)

“…The oceanic effect is the primary influencing factor for the mild temperatures and abundant precipitation. An average annual precipitation of approximately 1455 mm is recorded, with a mean summer temperature of 19.3 • C and 9 • C in winter [27].…”