Hydrodynamics and water quality modelling in a regulated river segment: application on the instream flow definition

Abstract

10The aim of this paper is to present a global study on the hydrodynamics, water quality and their influence on aquatic fauna. The case study was conducted on a segment of the Lima river (North Portugal), downstream of the Touvedo dam, which was mainly constructed for hydroelectric power production. The ISIS FLOW program was used to simulate the hydrodynamics. This model also generates the necessary input data for the water quality simulation using the ISIS QUALITY module. Two basic principles govern the ISIS programs: conservation of mass and momentum. Water quality parameters (dissolved oxygen and temperature) were simulated for different operational conditions of the Touvedo dam: different discharges (water quantity and duration) and two levels of the water withdrawal, where different water characteristics have been measured. We observed a modification in the hydrodynamics and in the water quality as a function of the outflow volume and discharge level by simulating the variation of dissolved oxygen and temperature downstream of the dam. 25The response of the fish community to this modification appeared to result in a negative impact on the migratory fish and in the salmonids being replaced by the more tolerant cyprinids. 27This work shows that the relation between physical habitat and the targeted aquatic species is a necessary but not sufficient condition for a viable population of aquatic species.

Effect of a dam on epilithic algal communities of a mountain stream: before-after dam construction comparison

“…Similar changes in the hydrologic regime and the small variation between periods have been reported (Magilligan et al, 2003;Gomes Lopes et al, 2004;Magilligan and Nislow, 2005;Poff and Zimmerman, 2010). Moreover, the CA performed with samples taken after dam construction showed a clear segregation of sites.…”

“…Dams also alter stability and availability of substrate and riparian vegetation and reduce sediment-carrying capacity leading to a reduction of suspended sediments downstream. On the other hand, the upstream effects include inundation of floodplains and the formation of new lakeshore vegetation types (Brandt, 2000;Merritt and Cooper, 2000;Newcomb et al, 2001;Poff and Hart, 2002;Jakob et al, 2003;Magilligan et al, 2003;Uehlinger et al, 2003;Gomes Lopes et al, 2004;Magilligan and Nislow, 2005;Olden and Naiman, 2010).…”

“…Dams are designed to store water and modify the magnitude and timing of its movement downstream. Although dams have had many advantages for industries and people (Brandt, 2000;Poff and Hart, 2002), numerous authors have reported that river regulation has a negative impact on the structure and function of lotic ecosystems (Hardwick et al, 1992;Kingsford, 2000;Magilligan et al, 2003;Uehlinger et al, 2003;Gomes Lopes et al, 2004;Magilligan and Nislow, 2005;Francoeur and Biggs, 2006;Nichols et al, 2006;Wu et al, 2010).…”

Impact of Water Projects on River Flow Regimes and Water Quality in Huai River Basin

“…The method is original and different from the former relative researches (Karr 1991;Lowney 2000;Albanakis et al 2001;Bednarek 2001;Campbell et al 2001;Lopes et al 2003Lopes et al , 2004Bartholow et al 2004;Klamath. Horne et al 2004;Mao 2005;Munoz et al 2006;Wei et al 2008).…”

“…Lowney (2000) derived an analytical model and illustrated the phenomenon of diurnal variation on steady flow and temperature over a 250 km regulated reach of the Sacramento River, located in the Central Valley of California. Lopes et al (2003Lopes et al ( , 2004 studied the influence of reservoirs exploitation on hydrodynamics and water quality downstream of reservoirs. The case study was conducted on the river Lima, downstream of Touvedo dam and a Mondego river segment between the Aguieira and Raiva dams by ISIS programs (ISIS FLOW module and ISIS QUALITY).…”