Hidrogeomorphological quality in fluvial areas of urban expansion. Application of the Hydrogeomorphological Index (IHG) in an anthropized stream (Napostá Grande creek, Argentina)

Abstract

Peri-urbanization changes the natural dynamics of fluvial processes. Human intervention can be seen in the riverbeds and also in land use changes, vegetation cover variations, and the capture of water resources. As a result, hydrogeomorphological indicators have become relevant for evaluating these impacts. In this article, the hydrogeomorphological quality of the Napostá Grande stream in the peri-urban area of Bahía Blanca, Argentina, is evaluated. The Hydrogeomorphological Index (IHG) was applied to functional sectors in order to analyze fluvial behavior against human intervention on a section scale. We compared the values obtained in 2016 and in 2021. Over the last five years, the hydrogeomorphological quality decreased mainly in the parameters of the quality of the riparian corridor and the quality of the channel. Likewise, variations intensify as the stream descends towards the more urbanized sectors. In terms of river health, the evaluations of the index and processes such as streamlining the channel show signs of deterioration that may require river restoration measures.