Hydrologic and geomorphologic features of the Río del Oro basin, La Rioja province, Argentina

Highlights

• Various morphological features were identified in the Río del Oro basin.

• Relictual and modern features allow interpreting the landscape dynamic evolution.

• Tectonic and paleoclimatic processes controlled the geomorphological development.

• Geology, climate and topography largely affect the dynamics and hydrological features.

Abstract

The analysis of the geomorphological features developed over a given area contributes to the knowledge of the processes that intervened in the evolution of the landscape, helping to reliably understand their interaction with the surface and underground water resources. The headwaters of the Río del Oro are in the Sierra de Famatina, which is located in the north center of La Rioja Province. Based on the collection and analysis of the bibliography and images of the study area and field work, several geomorphological features of the area were identified and characterized, in order to establish links with their locations and determine the agents and processes that acted in landscape modeling. In turn, a hydrological description was made to broaden the knowledge of the water resource of this area, which is essential according to the arid climatic conditions. Despite the aforementioned context, fluvial activity stands out as one of the main relief modelers, considering the neotectonics and the Quaternary climate changes as notable factors in evolution.

Introduction

The study of the forms that characterize a given landscape constitutes an essential requirement facing diverse analyzes that can be developed in a region, such as those oriented to its evolutionary history, characterization, territorial planning, natural risks, among others. This requires recognition, characterization and classification of the morphologies that account for the factors and processes that acted in their formation, and contribute to the interpretation and reconstruction of the evolution of the relief at diverse scales.

The arid climate of La Rioja Province generates a low surface runoff that limits the productive development of its localities and necessarily promotes the application of irrigation through catchment wells for a socio-economic development. In the Antinaco-Los Colorados valley, the concentration of villages and agricultural activities towards the central-western sector, together with the development of alluvial fans, suggest a greater supply of water from the Sierra de Famatina as opposed to the one from the Sierra de Velasco, mainly due to more abundant and frequent rainfall in the first one (Centro Regional de Agua Subterránea, 1975; de Alba, 1979; Turner, 1971) and larger basins.

The rivers del Oro, Amarillo and Miranda are the most important courses in the region that, together with other smaller ones, drain the eastern slope of the Sierra de Famatina (Fig. 1). At the foot of this latter, and after the confluence of other courses, they spread their waters towards the Bajos de Santa Elena, formed by numerous courses that intersect and run from north to south, representing the main drainage network of the Antinaco-Los Colorados valley.

The basin of the Río del Oro is located in the central-north region of the province of La Rioja, approximately between 28°58′ and 29°09′ S, and 67°29′and 67°50′ W (Fig. 1). It provides water to the populations located on its margins, among which are: Santa Florentina, San Nicolás, San Lorenzo, Chilecito, Los Sarmientos, Tilimuqui, San Miguel, Malligasta and Anguinán. Although originally the supply was made through channels and ditches, it is currently carried out through underground exploitation, since it only has surface runoff water during and after storms.

The study of this drainage basin, in addition to its relevance for the productive activities carried out in the area, contributes, through the analysis of geoforms, to the knowledge of the processes and geomorphological agents involved in the evolution of the landscape.