River ecosystem modelling: Application of the PROSE model to the Seine river (France)

Abstract

The Seine river crosses the most densely populated and industrialized area of France, Paris (16 million inhabitants), surrounded by fertile land with intensive agriculture.In the framework of a CNRS (Scientific Research National Center) research project, computer programs have been designed to tackle problems related to eutrophication, non-point pollution and the impact of sewage during dry or wet periods (urban runof and sewage network overflow). The PROSE software has been specially designed to simulate the behaviour of the most disturbed stretches of the Seine ecosystem on the last 300 kilometers of the river, upstream of the estuarine area.The I-D hydraulic sub-model of PROSE is based on a finite difference solution of Saint-Venant equations solved with the Preissman scheme. It simulates steady state situations as well as highly transient situations such as fast changes in river discharge during rainy periods or dam motions. The biological sub-model is based on the RIVE model, describing the major processes in a river ecosystem: primary production, heterotrophic bacterial activity and organic matter decomposition, major nutrients species (nitrogen, phosphorus), nitrifying activity and oxygen balance. Water column and sediment variables are simulated. Most of the parameters have been estimated during laboratory experiments or field studies.Different situations observed between 1989 and 1991 allowed a detailed validation of the modeL The model was then used to explore the reaction of the ecosystem (particularly its oxygen status) to changes in physical constrains (discharge, reoxygenation at dams) or in biological processes (release of microorganisms accompanying waste water discharge).

Identification of a minimal adequate model to describe the biomass dynamics of river epilithon

“…Since Streeter and Phelps (1925) started modelling river water quality, ecological models have been increasingly used by environmental managers, especially from the beginning of the 1970s (Brown and Barnwell, 1987;Even et al, 1998;Reichert, 2001;Reichert et al, 2001). One fundamental goal of ecological modelling is to predict how the structure and function of communities respond to change, not only because streams and rivers are naturally variable, but also because they are vulnerable to anthropogenic disturbances (Power et al, 1988).…”

Use and Utility: Exploring the Diversity and Design of Water Models at the Science-Policy Interface

“…Originally designed to study problems of water quality and chronic deoxygenation related to effluent discharges from wastewater treatment plants on downstream sectors of the river and accidental overflow of sewage networks during rainy events [60,61], it has also been applied to hydraulic problems and questions associated with the transport of particles [60].…”

Geostatistics for assessing the efficiency of a distributed physically‐based water quality model: application to nitrate in the Seine River

“…The quantitative modelling of in‐stream water quality began with a simple conceptual model (Streeter and Phelps, 1925), which was based on oxygen. After this initial step, carbon cycle and then nutrients were added, leading to modern water quality models (Barnwell et al , 1987; Brown and Barnwell, 1987; Ambrose et al , 1988, 1996; Billen and Servais, 1989; Crabtree et al , 1994; Reichert, 1994; Garnier et al , 1995; Ivanov et al , 1996; Even et al , 1998, 2004; Wells, 2000; Wool, 2001). Contrary to the conceptual model by Streeter and Phelps (1925), the biogeochemical processes are nowadays physically based and the transport is based on hydraulic fluxes.…”