Modelling thermal stratification and artificial de-stratification using DYRESM; Case study: 15-Khordad reservoir

In this study, a one-dimensional model called DYRESM was used to simulate the thermal structure and artificial destratification of 15-Khordad Reservoir over a period of one year. The simulation showed that the reservoir is warm monomictic and is stratified during 210 days of the simulation year. The model reproduced the temperature of the meta- and hypolimnion very close to the observed data, but the temperature of the epilimnion was overestimated. As the meteorological data used for the simulation was collected in a nearby weather station, a sensitivity analysis was conducted to evaluate the effect of meteoro-logical data bias on the simulation results. Air temperature, shortwave solar radiation, wind speed and vapour pressure were found to be, respectively, the most effective parameters. Furthermore, applications of two artificial destratification systems: bubble plume diffuser and surface mechanical mixer, were modelled. The sensitivity of the model outputs to the specifications of each system was investigated and the two systems were compared considering their efficiencies. It was revealed that the air diffusers were much more efficient than the mechanical mixers. This study showed that the DYRESM can accurately describe physical processes in this reservoir if the forcings are accurately given and the application of bubble is recommended for artificial destratification in this reservoir.

Keywords
Modelling, De-stratification, Plume, Diffuser, Mixer, DYRESM, Simulation, Reservoir