Trophic Upsurge in New Reservoirs: A Model for Total Phosphorus Concentrations

Abstract

A model for total phosphorus concentrations during both the trophic upsurge and depression phases in new reservoirs has been developed by a convolution of the rate of phosphorus leaching from flooded lands and the rate of reservoir filling. Model parameters for phosphorus sedimentation and leaching coefficients were estimated from data available on the Smallwood Reservoir (impoundment 1971) in Labrador. The model was subsequently applied to predict phosphorus concentrations during the trophic upsurge phase in the La Grande-2 (LG2) Reservoir (impoundment 1978) in the James Bay region of Quebec. Because the sparse data available on other new or old reservoirs during the trophic upsurge phase does not permit an analysis of the confidence limits in model output, we include discussion of the calculated values of model parameters and their relationship to the real phenomena. An evaluation of the rates of phosphorus leaching from flooded soils and vegetation and the specific leaching coefficient of phosphorus from various lands has shown indirectly that the proposed model approximates the dynamics of new reservoir phosphorus concentrations. We conclude that the model has a good potential as an empirical predictive tool in the management of large new reservoirs on the Canadian Shield.Key words: reservoir, phosphorus, model, trophic state

Hydropower – A Green Energy? Tropical Reservoirs and Greenhouse Gas Emissions

“…The eutrophication process is a well-known phenomenon of dammed rivers, called the trophic upsurge [24,30]. This trophic upsurge is caused by a change in the hydrological conditions from running water with transverse nutrient transport by water flow, a nutrient spiral, to standing waters with a vertical nutrient cycle.…”

State-of-the-art of reservoir limnology and water quality management

“…Hecky et al (1984a) studied the effects of internal loading of sediments that arise from shore erosion. Mathematical expressions for nutrient leaching from soils were developed by Ostrofsky & Duthie (1978), which led to the development of a hypothesis and a model of trophic upsurge in reservoirs (related to phytoplankton development) based on phosphorus leached from soils as the dominant variable (Ostrofsky, 1978;Grimard & Jones, 1982). Another quantitative model in respect to near-bottom oxygen depletion (Kozerski, 1975) takes into account soil qualities and reservoir stratification.…”

Environmental effects of reservoirs

“…In either case, the growth of phytoplankton is favored by the release of nutrients such as phosphate from the flooded plants and soil. This often leads to a burst of increased primary productivity, which has been referred to as the trophic upsurge (Baranov, 1961;Ostrofsky & Duthie, 1980;Grimard & Jones, 1982). This usually lasts only a year or two, often to be followed by a much longer period of lower productivity or trophic depression, and eventually a smaller increase (Baranov, 1961).…”