Hydraulic mangement of filamentous algae in open-channel networks : case study in Southern France

International audiencePeriphyton 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

Indicators related to BMP performances: operational monitoring propositions Suivi opérationnel des performances des techniques alternatives, quelles mesures ?

RÉSUMÉ Depuis de nombreuses années, les techniques alternatives se sont multipliées en France comme dans de nombreux pays. Ces techniques offrent des performances très intéressantes du point de vue du traitement des pollutions et sur le plan hydrologique. Cependant, ces techniques permettent également de rendre de nombreux services tout aussi importants : préservation de l'environnement, amélioration du microclimat local, valorisation de l'eau pour la vie urbaine (activités sociales et récréatives), etc. Cette communication cible plus particulièrement les praticiens en proposant une synthèse des performances à évaluer et des indicateurs utilisables pour ces évaluations. L'évaluation des performances doit permettre de suivre dans le temps chaque technique alternative. La communication propose également des protocoles de suivi en fonction des performances à suivre. ABSTRACT This communication proposes a review on performance indicators related to the assessment of Sustainable Urban Drainage Systems (SUDS). The proposed indicators aims practitioners who want to monitor the performance of their technologies. A broad range of indicators related to hydraulic performance, hydrologic performance, economical aspects, others environmental and sanitary, social aspects, lifespan and long-term effectiveness are proposed. Indeed, the performance of sustainable drainage systems should not be limited to pollution and hydrology. Such systems play a broader role within integrated urban water management, providing benefits such as landscape amenity and amelioration of the biodiversity. This communication also proposes the construction of survey terms and data acquisition methods whose goal will be to assess the delivered service. The survey may be used to obtain feedback to assist in improving the design or the management of SUDS

Measurement of the atmospheric muon depth intensity relation with the NEMO Phase-2 tower

The results of the analysis of the data collected with the NEMO Phase-2 tower, deployed at 3500 m depth about 80 km off-shore Capo Passero (Italy), are presented. Cherenkov photons detected with the photomultipliers tubes were used to reconstruct the tracks of atmospheric muons. Their zenith-angle distribution was measured and the results compared with Monte Carlo simulations. An evaluation of the systematic effects due to uncertainties on environmental and detector parameters is also included. The associated depth intensity relation was evaluated and compared with previous measurements and theoretical predictions. With the present analysis, the muon depth intensity relation has been measured up to 13 km of water equivalent.Comment: submitted to Astroparticle Physic

Cryogenic SiPM arrays for the DUNE photon detection system

In this paper we report on the characterization of SiPM tiles developed for the R & D on the DUNE Photon Detection System. The tiles were produced by Fondazione Bruno Kessler (FBK) employing NUV-HD-SF SiPMs. Special emphasis is given on cryo-reliability of the sensors, i.e. the stability of electric and mechanical properties after thermal cycles at room and 77K temperature. The characterization includes the determination of the I-V curve, a high sensitivity measurement of Dark Count Rate at different overvoltages, and correlated noise. The single p.e. sensitivity is measured as a function of the number of sensors connected to a single electronic channel, after amplification at 77K using a dedicated cold amplifier.Comment: 17 pages, 10 figures, 4 table, submitted to NIM-