Présentation générale de l'aménagement hydroélectrique de Petit-Saut (Guyane française) et du programme de suivi écologique lié à sa mise en eau

Abstract

-Petit-Saut dam is located on the Sinnamary river in French Guiana. At full supply level (El. 35), the reservoir stretches over approximately 310 km2 of wet rain forest left uncleared; the total storage is 3500 I O 6 m3 (useful storage of I O 9 m3 between El. 35.00 and 31.50, the minimum operating level). In addition, there are 110 km2 of islands and peninsulas by reason of the rolling topography of the site. Mainly because of the poor hydraulic conditions in 1994-95 and the impounding stages required to monitor the structures' behavior, reservoir impounding took 18 months, giving EDF an opportunity to design and build systems to re-oxygenate and degas the oxy-gen-poor discharge from the turbines with its high reduced gas content (forced re-aeration by compressed air diffusers and construction of a weir to create a double set of falls in the tailrace channel). Throughout the impounding, EDF, with the help of a Scientific Committee, implemented an ecological monitoring program that is expected to continue through the first three years of operation (mid 1995 -mid 1998). This program mainly addresses water quality (chemical and biological aspects), hydrological modifications, protection of land fauna (rescue, transfer, modifications following fragmentation of the environment), structural modifications and changes in the flora in the surrounding forest, as well as operations in view of archaeological preservation. This program required that the reservoir, its surroundings and the wildlife release area