Modélisation de l'azote total en rivière à l'aide du modèle quantité–qualité CEQUEAU

Abstract

A model for nitrogen concentrations in running waters has been developed and associated with the hydrological model CEQUEAU. The model allows the simulation of total nitrogen concentrations at any point in a watershed during various hydrological event. The catchment area is first subdivided into discrete elements; each element is associated with a production function which quantifies the accumulation of nitrogen at the soil–atmosphere interface. Supplementary functions describe the transformations of nitrogen species in the soil and the transfer of the nitrogen load towards the hydrographic system by runoff (caused by rain and (or) snowmelt), and the transport of the different nitrogen compounds downstream. Another function is used to represent the in-stream transformation. Nitrogen data inputs to be modeled are those from precipitation dry deposition, diffuse sources due to agricultural practices, and industrial point sources. The model was applied to the Sainte-Anne River, Québec (catchment area, 2700 km2) in order to reproduce the observed nitrogen concentrations for 1978, 1979, and 1980. Model performance was judged to be promising and it is proposed to validate the model by the simulation of nitrogen concentration on the other rivers for which land use and industrial activity are well documented. Key words: modeling, river, nitrogen, supply, runoff, seepage, drainage.

Hydrologic impact of climate change in the Saguenay watershed: comparison of downscaling methods and hydrologic models

“…Two conceptual hydrologic modeling systems, namely the Swedish HBV-96 (Bergström and Forsman, 1973) and the Canadian CEQUEAU (Morin et al, 1983) have been employed in this study. HBV is an integrated hydrological modeling system developed at the Swedish Meteorological and Hydrological Institute, and has been applied to a wide range of applications including analysis of extreme floods, effects of land-use change and effects of climate change (Lidén, 2000).…”

“…A more detailed description of the HBV-96 can be found at http://www.indic-airviro. smhi.se/HBV/ CEQUEAU is also a distributed hydrological model, which takes into account the physical characteristics of the basin by subdividing it in elementary representative areas (ERA), also called whole squares, which are assumed to have homogenous features (Morin et al, 1983). It is a water-balance-type conceptual model with distributed parameters.…”

Quantifying the effect of in-stream rock clasts on the retardation of heat along a stream

“…Transport of heat has also been coupled with distributed hydrological models. Morin et al [30] developed CEQUEAU, a 3D hydrological model able to model temperature in the whole model domain. St-Hillaire et al [37] adapted this model to more accurately simulate the subsurface temperature yielding a better estimate of the temperature of the groundwater inflows into a stream.…”

Illustration of the added value of using a multi-site calibration and correction approach to reconstruct natural inflows and inter-catchment transfer flow: a case study

“…CEQUEAU also includes a water temperature model and a water quality model that can both be used for instance in the context of environmental impact assessment studies (e.g., St-Hilaire et al 2003;Morin et al 1988). …”