Fovet O., Belaud Gilles, Lancar L., Litrico X., Baume J.P., Malaterre P.O., Genthon O. (2009). Hydraulic management of filamentous algae in open-channel networks : case study in Southern France.
10 p. multigr. Symposium on Ecohydraulics : 8. Conference on Hydroinformatics, 7., Concepcion (CHL), 2009.
Titre du document
Hydraulic management of filamentous algae in open-channel networks : case study in Southern France
Symposium on Ecohydraulics : 8. Conference on Hydroinformatics, 7., Concepcion (CHL), 2009
Periphyton constitutes the benthic compartment of aquatic environments such as artificial channels which are specific eco-systems for many reasons. Firstly, they have to fulfill hydraulic performance and water quality objectives. These objectives may be affected by filling problems due to algal developments and sanitary risks linked to toxins secreted by Cyanobacteria. Second, compared to natural streams, artificial channels have a relatively simple geometry and their hydraulic variables are easier to monitor. Also, cross regulators allow the managers to control discharges and water elevations. Periphyton dynamics depend on several factors and hydrodynamic is one of the most crucial one. In this article we analyze an original strategy for algal control currently used in a branch of the Canal de Provence (South of France). The management strategy consists of regular flushes causing increases of the bed shear stress from upstream to downstream and consequently algal filament cutting. This is achieved by increasing the discharge at the upstream end of the branch. We first show that turbidity can be used as an indicator for algal detachment. Then, a detachment model is proposed and coupled with the hydrodynamic simulation of the system. It can be fitted very satisfactorily on the turbidity measurements and can be used to improve the management strategy, such as reducing the discharge released.
