Hydrodynamic ecohydraulic habitat assessment aimed at conserving and restoring fluvial hydrosystems

Fluvial conservation and restoration measures' efficiency was evaluated in terms of ecological state enhancement, comparing future scenarios with historical or altered conditions. Ecohydraulics provides valuable scientific fools for the environmental diagnosis of lotic ecosystems, evaluating the combined effect of flow regime and channel structure on habitat quality for aquatic biota. This paper adopts an analytic-synthetic approach to the interdisciplinary challenge of fluvial ecohydraulics for computational fluid dynamics (CFD) within the framework of ecosystem water management. The procedure for multidimensional (2D/3D) evaluation of the physical aquatic habitat is described as well as its predictive ability and main applications. The 2D depth-averaged scheme is highlighted whose velocity simulation error (being normally lower than 10%) overcomes classic one-dimensional (1 D) simplifications. The basic aspects of biological habitat modelling, abiotic variables and biological preference are summarised. Combining ecological criteria with hydrodynamic flow patterns is illustrated for producing discrete habitat fields which were then spatially and temporarily integrated in ecohydraulic analysis.