TY  - JOUR
A1  - Lobera, Gemma
A1  - Andres-Domenech, Ignacio
A1  - López-Tarazón, José Andrés
A1  - Millan-Romero, Pedro
A1  - Valles, Francisco
A1  - Vericat, Damia
A1  - Batalla  Villanueva, Ramon J.
T1  - Bed disturbance below dams: observations from two Mediterranean rivers
JF  - Land degradation & development
N2  - River-bed disturbance and associated sedimentary processes such as particle mobility are central elements to assess river ecosystem functioning. Dams change river dynamics affecting the magnitude and frequency of biophysical elements that depend on them. This paper examines the effects of two dams different in size, management, and location, on the flow regime, flood competence, and bed disturbance in two contrasting Mediterranean rivers, the Esera and the Siurana. For this purpose, two reaches on each river were monitored upstream and downstream from reservoirs. Several monitoring and modeling techniques were used to characterize flow competence, particle entrainment, and the volumes of sediments eroded and deposited after floods. The flow regime of the Esera has been modified from nivo-pluvial regime, typical of humid mountainous environments, to that observed in dry semiarid regions, in which high magnitude but low frequency floods are the dominant processes. Conversely, the flow regime of the Siurana has changed from a typical Mediterranean stream to a regime observed in more temperate environments, with more permanent and stable flows. Both rivers show notably physical changes, with channels clearly less dynamic below the dams. The lack of competent flows together with the sediment deficit associated with the dams has led to less active fluvial environments (reduced particle mobility and bed scour dynamics), a fact that affects instream habitat structure (more uniform grain size distribution, less physical heterogeneity, more stable flows), overall contributing to the degradation of the stream corridor and the subsequent environmental deterioration of the whole fluvial landscape. Copyright (c) 2017 John Wiley & Sons, Ltd.
KW  - flow regime
KW  - dams
KW  - bed disturbance
KW  - sediment mobility
KW  - Mediterranean rivers
Y1  - 2017
U6  - https://doi.org/10.1002/ldr.2785
SN  - 1085-3278
SN  - 1099-145X
VL  - 28
SP  - 2493
EP  - 2512
PB  - Wiley
CY  - Hoboken
ER  -