Do the morphological characteristics of Chilean gravel-bed rivers exhibit latitudinal patterns?

Ulloa, H, Iroume, A, Picco, L, Vergara, G, Sitzia, T, Mao, Luca and Mazzorana, B (2020) Do the morphological characteristics of Chilean gravel-bed rivers exhibit latitudinal patterns? Journal of South American Earth Sciences, 99 . pp. 1-12. ISSN 0895-9811

Full content URL: https://doi.org/10.1016/j.jsames.2020.102522

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Do the morphological characteristics of Chilean gravel-bed rivers exhibit latitudinal patterns?
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Item Type:Article
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Abstract

Gravel-bed rivers exhibit remarkable dynamics and distinctive morphological patterns which influence the
biological processes, as well as the river ecosystem resilience to human impacts. Classifications of river ecosystems
into groups with morphologically distinct patterns are therefore of paramount importance for a better
understanding of their dynamics, their management and conservation.
Investigations on fluvial morphology and the related dynamics in Chilean gravel-bed rivers are still scarce,
and, so far, no efforts have been made to identify latitudinal patterns of their morphological characteristics that
may serve as a basis for further classification purposes. In fact, the great variability in bio-geographic, climatic,
geologic and geomorphologic settings of the country offer an almost unique opportunity to study how the
morphological characteristics of gravel-bed rivers may vary within extremely heterogeneous environments.
We performed a regional analysis of nineteen Chilean gravel-bed rivers, from semi-arid Mediterranean to
rainy temperate conditions (latitude ranging from 32° S to 39° S). Planform characteristics within these reaches
were identified through interpretation of satellite images. Topographic features of the river basins were derived
from open source digital elevation models and water discharge values were obtained from available national
databases.
We addressed the following research questions: a) can these 19 rivers be grouped into clusters considering
their distinct planform characteristics of the river channel and basin features, as related to latitudinal gradients?,
b) do river morphological characteristics vary along the analyzed latitudinal gradient?, c) does the distribution
of specific geomorphic units (i.e. islands) follow a longitudinal pattern?, and finally, d) are these units associated
to specific hidrogeomorfic characteristics?
We generated a clustering which reflects latitudinal and morphological gradients in Chilean gravel-bed rivers,
with the northernmost and southernmost rivers grouped according to their distinctive hydro-morphological
characteristics and geomorphic units. We also observed a general tendency of an increase in the proportion of
fluvial islands relative to the active channel area from the 33° Latitude in southward direction.

Keywords:River patterns, Gravel-bed river, Latitudinal pattern, Morphological characteristics, Chile
Subjects:F Physical Sciences > F820 Geomorphology
Divisions:College of Science > School of Geography
ID Code:40163
Deposited On:06 Mar 2020 09:26

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