E3S Web Conf.
Volume 40, 2018River Flow 2018 - Ninth International Conference on Fluvial Hydraulics
|Number of page(s)||8|
|Section||River morphodynamics and restoration|
|Published online||05 September 2018|
Targeted water releases to flush fine sediment out of a bypassed reach of the Durance River downstream of four dams
EDF, Hydro Engineering Center, Savoie Technolac, 73323, Le Bourget du Lac, France
2 University of Lyon, UMR5600 CNRS EVS, ENS Lyon, 15 Parvis R. Descartes, France
3 SAGE Environnement, 12 Ave du Pré de Challes, 74940, Annecy Le Vieux, France
4 EDF Mediterranean Production Unit, 10 Ave Vitton, 13482, Marseille Cedex 20, France
The Durance River is a highly regulated, gravel-bed river with a naturally high fine sediment load in southern France. EDF operates eight dams along the regulated main stream channel (218 km from the Serre-Ponçon Dam to the confluence with the Rhône River), that divert water to 16 hydroelectric power plants via a canal. Flow regulation has contributed to fine sediment accumulation (clogging) in the Durance River. In addition to a recent increase in minimum flows has implemented targeted water releases at four out of eight dams to simulate floods and reduce clogging to restore river function for fishes and invertebrates, The timing of these releases is defined for each dam based on the spawning period of target fish species. During the release, TSS, O2, T, H, and conductivity are measured continuously. Before and after each release, clogging (superficial/interstitial) is measured. This monitoring program showed that several of the releases were not effective on surface clogging inducing a loss of water or resulted in effects contrary to those sought, although this was not reflected in the biological results. These results indicate that two parameters must be taken into account to determine a priori the need to carry out releases: the hydrology observed during the year and the initial level of clogging. Artificial flood releases are increasingly being used a management tool to mitigate hydropower impacts on river hydromorphology and ecology. This experimentation shows that it is necessary to carry out these types of operations in an adaptive management context. At this time, the results obtained do not lead to clear conclusions regarding their efficacy, mostly as a result of strong interannual variation in hydroclimatic conditions, which have a strong influence on initial conditions and resulting outcomes. Furthermore, it is important to incorporate this field measurements and not rely solely on turbidity gauging stations to evaluate efficacy.
© The Authors, published by EDP Sciences, 2018
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (http://creativecommons.org/licenses/by/4.0/).
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.