Authors: Sabine Schmidt Clément Bernard JeanMichel Escalier Henri Etcheber Mélina Lamouroux
Publish Date: 2016/09/14
Volume: 24, Issue: 4, Pages: 3251-3259
Abstract
The Gironde estuary SW France is one of the largest European macrotidal estuaries In the tidal Garonne River its main tributary episodes of low 5 mg L−1 to hypoxic 2 mg L−1 dissolved oxygen DO concentrations have been occasionally recorded close to Bordeaux about 100 km from the mouth Projected longterm environmental changes increase in temperature and population decrease in river discharge suggest the establishment of summer chronic oxygen deficiency in the tidal Garonne River in the next decades Assessing and managing the risk of hypoxia on such a large hyperturbid fluvioestuarine system is complex due to the different forcing factors temperature river discharge turbidity urban wastes acting over a wide range of temporal and spatial scales In this context we show the interest of a realtime highfrequency monitoring of the water quality the MAGEST network which continuously records since 2005 temperature salinity turbidity and dissolved oxygen in surface waters in Bordeaux Through the analysis of the 10year DO records we demonstrate the interest of a highfrequency longterm database to better document DO variability and to define the controlling factors of DO concentrations This realtime monitoring is also of great interest for the development of manager’s oriented tools and the followup of DO objectives in the tidal Garonne RiverThis network is funded by the following organisms AEAG Agence de l’Eau AdourGaronne SMIDDEST Syndicat MIxte pour le Développement Durable de l’ESTuaire de la Gironde SMEAG Syndicat Mixte d’Etudes et d’Aménagement de la Garonne EPIDOR Etablissement Public Interdépartemental de la Dordogne EDF GPMB Grand Port Maritime de Bordeaux CUB Communauté Urbaine de Bordeaux Conseil Régional Aquitaine CG33 Conseil Général de Gironde IRSTEA CNRS and Université de Bordeaux
Keywords: