The IHG index for hydromorphological quality assessment of rivers and streams: updated version

Abstract

The IHG index for hydromorphological quality assessment of rivers and streams: updated versionAn updated version of the IHG index is presented. The index is based on three appraisal parameters: 1) the functional quality of the fluvial system, including a) flow regime naturalness, b) sediment supply and mobility, and c) floodplain functionality; 2) the channel quality, including a) channel morphology and planform naturalness, b) riverbed continuity and naturalness of the longitudinal and vertical processes, and c) riverbank naturalness and lateral mobility; and 3) the riparian corridor quality, including a) longitudinal continuity, b) riparian corridor width, and c) structure, naturalness and cross-sectional connectivity.

The European REFORM Project for Hydromorphological Quality in River Basin Management

“…Their suitability for diagnosing alteration, however, was found to be limited because the methods insufficiently considered the physical processes of natural fluvial systems that maintain or recreate fluvial forms and thereby physical habitats. This contrasted with recent scientific developments that base the interpretation of current conditions on attempts to understand river functioning and evolution, see for instance [7][8][9][10][11].…”

Morphometric Prioritization, Fluvial Classification, and Hydrogeomorphological Quality in High Andean Livestock Micro-Watersheds in Northern Peru

“…The hydrogeomorphological quality of each FS of the HAL-MWs was evaluated with the use of the IHG Index [19,46,96]. In the laboratory, hydrological and infrastructure documentation, satellite images (recent and old to assess the change processes; Figure 4), and cartography (terrain topography, land use and road network) were acquired to distinguish pressures and impacts on the river system that may distance its functionality, continuity, naturalness, complexity, and dynamics from a reference state [44].…”

“…However, these points were subtracted when impacts and damage were observed in accordance with every subsection criterion in the IHG Index. Final hydromorphological quality is calculated according to each FS' final score in conformity with Table 3 [46].…”

“…For example, the Hydrogeomorphological Index (IHG) was developed in 2007 [19] and successfully applied in Spanish river channels [44,45]. It was consequently modified [46] and applied in other basins in Spain [47,48] and also adapted by South American countries such as Argentina [49], Chile [50,51], and Peru [37,38]. In Peru, there is no framework for river system hydrogeomorphological evaluation, but establishing such a framework is of primary importance due to the rugged high Andean territory and high non-uniform rainfall, which promote highly dynamic river behavior, in space and time.…”