An Integrated Ecohydraulic Approach to Assess Surface Water-Groundwater-Riparian Vegetation Interactions
Abstract
Among renewable energy sources, hydropower plays a fundamental role, despite the recognition of its negative side effects (e.g. on river-aquifer interactions, sediment fluxes, riverine ecosystems, etc.), which are often difficult to quantify, especially in alpine rivers. We argue that the long-term consequences of river regulation on hydraulic processes and riparian vegetation, in particular in gravel-bed braided streams, can be conveniently investigated by means of multi-decadal numerical simulations, which model explicitly the interactions between surface-subsurface water fluxes and floodplain vegetation establishment, growth and erosion.
Here we present an integrated approach for modelling interactions between hydrology, river-aquifer dynamics and vegetation at the river corridor scale. This consists of a coupled surface-subsurface model suitable for gravel-bed braided river floodplains (S2R2: Ruf et al., Peckiana 5, 2008; Shaad, ETHZ doctoral diss. 22600, 2015; Bergami et al., in prep.) and a riparian vegetation dynamics model (RVDM: García-Arias & Francés, Ecohydrology 9, 2016), used to analyse the impacts of streamflow regulation on riparian vegetation in the Maggia River. This is an alpine stream controlled by a hydropower system and monitored in terms of streamflow and groundwater levels, bed morphology, riparian vegetation, and aquatic ecosystem. The coupled surface-subsurface model (S2R2) consists of a two-dimensional shallow water flow simulator (2dMb) coupled to a groundwater model (MODFLOW) on a high-resolution regular grid (12.5 m) and with a fine temporal discretization. The vegetation model works on the same grid at a daily time scale over multiple decades and models the vegetation dynamics driven by spatially explicit variables simulated by S2R2. This modelling framework can be employed to investigate scenarios accounting for different hydropower operation strategies, which, in turn, can account for climate change and energy market impacts. We argue that the modelling framework is useful as a predictive tool to simulate proxy variables for river health indicators, which help quantify the effects of different hydropower operation policies aimed at establishing dynamic environmental flows that minimize the disturbance to hydraulic processes and riparian vegetation.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.U12C..08B
- Keywords:
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- 0810 Post-secondary education;
- EDUCATION;
- 0815 Informal education;
- EDUCATION