How vegetation can aid in coping with river management challenges: A brief review

Abstract

New sustainable, cost-effective solutions are urgently needed for river management since conventional practices have posed serious ecological threats on streams, rivers and the surrounding riparian areas. Besides addressing the societal needs e.g. for flood management, river management should increasingly address the ecosystem requirements for improved water quality and biodiversity. We argue that it is not feasible to solve existing and future river management challenges with intensive restoration projects. Instead, we believe that less resource-intensive solutions using natural channel processes and features, including vegetation, should be investigated. Besides directly supporting biota, aquatic and riparian vegetation traps, takes up and helps to process nutrients and harmful substances, and thus this paper emphasizes vegetation as a tool for nature-based solutions (NBS) in river management. In this paper, emphasis is placed on the usage of vegetation as a NBS in river management. We synthesize findings from key literature, showing that the fate of substances in channel systems is largely controlled by abiotic and biotic processes facilitated and modified by vegetation, including flow hydrodynamics, channel morphology, and sediment transport. Subsequently, we demonstrate how vegetation can be incorporated into channel designs, focusing on a two-stage (compound) design to improve resilience to flooding, control the transport of substances, and enhance the ecological status. As a conclusion, clever use and maintenance of vegetation present unused potential to obtain large-scale positive environmental impacts in rivers and streams experiencing anthropogenic pressures.

Evaluation of Flow Resistance Models Based on Field Experiments in a Partly Vegetated Reclamation Channel

“…The presence of backwater in manmade reclamation channels enhances the growth of riparian vegetation, promoting the expansion of aquatic and terrestrial habitats and improving water quality [1,2]. In this context, the analysis of the real-scale interaction between riparian plants and water flow in vegetated channels can provide relevant hints to the administrators of land reclamation areas, about the most useful approaches to be followed when managing the riparian vegetation, which can ensure the conveyance capacity of the channel with limited impacts on the natural habitats [1].…”

The Interplay between Flow Field, Suspended Sediment Concentration, and Net Deposition in a Channel with Flexible Bank Vegetation

“…Therefore, the interface region is of major importance, as it controls the lateral transport of suspended sediment (SS) and net deposition in the vegetated areas. Maintenance of the floodplain/riverbank vegetation provides means not only to enhance flow conveyance and prevent excessive flooding, e.g., [6] but also to control SS transport and net deposition [4,7]. Important advances in the mean flow and the turbulent flow fields were gained in partly vegetated flumes by assuming plants behave as rigid cylinders; e.g., [8,9].…”

Seasonal changes in hydraulic flow conditions in overgrown lowland river

“…Understanding the impact of plants on hydraulic and morphological conditions in the riverbed is necessary in the case of ecological river regulation (restoration of rivers) and NBS (nature-based solutions), where specifically selected plants in terms of species and density can perform specific functions such as flow deflectors [15,16].…”