HYDROLOGICAL MODELLING

Modelling the dispersion of radionuclides, pollutants, and cooling water in the aquatic environment

Lake Modelling: box-models LAKECO-B and LATOX

R. Heling. NRG Arnhem, department of Radiation and Environment

Two different models for predicting the pollutant behaviour in lakes

1. LAKECO-B: dispersion of pollutants in shallow lakes
2. LATOX: dispersion of pollutants in deep stratified lakes

The Compartment Models

Calculate the fate and behaviour of pollutants after accidental releases in lake ecosystems. It gives the concentration as a function of time:

• Water column (dissolved/adsorbed)
• Bottom sediments
• Aquatic organisms (LAKECO only)

Time-scale and spatial scale

• Middle and long term behaviour of pollution in lakes, up to thousands of years
• Lakes with a minimum size 0.1 km²
• Inner seas (LATOX only)

Special Features

• LAKECO-B predicts the pollutant concentration in the various trophic levels. Different fish types can be distinguished, and concentration in plankton, and mollusc can be predicted.
• LATOX predicts season-dependent vertical temperature profiles versus time on the basis of climatological data.
• LATOX predicts stratification patterns and mixing periods with a minimum of input data.

Figure: Predicted Vertical Temperature Profile in an artificial lake in the Netherlands

Validation

LAKECO-B has been validated on a large number of lakes in Europe: e.g. Ijsselmeer (The Netherlands), and Hillesjon in Sweden and on the Chernobyl Cooling Pond. LATOX has been validated on Lake Constance (Germany), and on the Black Sea, and has been applied on an artificial pond in the Netherlands

Other lake models: THREETOX and COASTOX