Lake Teletskoye is a unique natural reservoir in the south of Western Siberia and is connected to the Biya river. This lake is about 70 km by 3 km and has a maximum depth of about 320m. A special version of Delft3D is used for 3D hydrothermodynamic modelling in combination with 2D ice dynamics modelling. The water motion in the vertical direction largely depends on the characteristics of turbulence. Turbulent viscosity in such a deep lake is dominated by density stratification. For this reason, Delft3D-FLOW has been extended with an extra formula for the equation of state, namely the TEOS-10 formula. Via the Delft3D open source website the source code is available for other users as well. During winter lake Teletskoye is usually only partially covered with ice. This reservoir is therefore a suitable case study for the calibration of the Delft3D ice dynamics model. In this presentation the model results will be shown.

1. Numerical modelling of hydro, thermal and ice dynamics
with application to Teletskoye Lake, Altai Republic, Russia
04-11-2014, Delft
ИВ П
Erik De Goede
Deltares
Delft, the Netherlands
Konstantin Koshelev
IWEP SB RAS
Barnaul, Russia

2. Content
1. Teletskoye Lake as a case study
2. Numerical results
3. Resume
4. Conclusion

3. Introduction
In terms of climate change and increasing human pressure on water bodies and their watersheds urgent task is to improve water and environmental monitoring of the environment.
One of direction of solving the problem is to develop mathematical models of hydrological and physico-chemical processes for assessing and predicting the state of ecosystems in large lakes and reservoirs.
This requires the implementation of the correct setting of simulation (specified description of effective turbulent exchange, the formation of density stratification (thermocline and thermal bar), density flows, seiche fluctuations, etc.

4. A case study
Телецкое озеро
length – 78 км;
maximum width – 5,2 км;
average width– 2,9 км;
maximum depth- 323 м;
average depth – 174 м;
volume – 41,1 км3;
external water exchange- 5,3 years;
70 permanent and 150 temporary inflows;
low water temperature during the year;
low salinity water– 57-110 μS/см.

5. Teletskoye Lake as a case study
For the development of methods for mathematical modeling of deep stratified reservoirs, we experimentally and theoretically studied the thermal and gas regimes in Teletskoye Lake - a unique natural reservoir in the south of Western Siberia.
The Teletskoye Lake ecosystem is complex and has been studied in many major national and international research programs.
In the 90’s Teletskoye Lake was considered as one of the reservoirs analog of the designed Katun reservoir in the environmental assessment study of the Katun hydroelectric power plants project. A number of 1DV-models for physical and chemical processes in deep stratified reservoirs have been developed in IWEP SB RAS (Zinoviev A.T.).

6. Visual form of Teletskoye Lake basin DEM
To simulate the physical and chemical processes in Teletskoye Lake, data on the morphometric characteristics of its basin are required
On the basis of the field data in a GIS project "Teletskoye Lake" the digital elevation model (DEM) of the lake basin was built (Marusin K.V.)

7. Numerical results A special version of Delft3D
The sea-ice module in Delft3D, which is a flexible integrated modelling suite for hydrothermodynamics, morphology (waves, water quality) and interactions between these processes. (Erik De Goede)
The state equation in which density is a function of temperature, salinity and pressure. TEOS-10 and the Chen-Millero empirical formulas are implemented.
Other important Delft3D parameters
Z-model with 60-80 layers, k-e turbulence model, vertical eddy viscosity/diffusivity
Ocean heat flux model, Secchi depth
Weather data
Albedo of ice/snow

8. Typical velocity magnitude

9. Comparison of calculated and measured* temperature distribution along the vertical direction in the deepest point of the Teletskoye Lake 25.07.2013
* Zinoviev A.T., Dyachenko A.V.

10. Comparison of calculated and measured* temperature distribution along the vertical direction in the deepest point of the Teletskoye Lake 29.08.2013
* Zinoviev A.T., Dyachenko A.V.

11. Comparison of calculated and measured* temperature distribution along the vertical direction in the deepest point of the Teletskoye Lake 17.10.2013
* Zinoviev A.T., Dyachenko A.V.

12. Computed temperature on 13.03.2014

13. The typical density stratification for the summer

14. Density stratification for the autumn period

15. Density stratification for the autumn season. An example of an unstable stratification

16. Typical density stratification for the winter period

17. Typical density stratification for the spring period

18. Comparison of different approximations for effective back radiation
Tsurface=0 C, Relative humidity=50%, Cloud coverage=70%

19. Computed ice thickness during the coldest period

20. Computed ice thickness on 13.03.2014

21. Resume
The calculation results in the summer stable stratification period are in good agreement with the available measured data.
The calculation results in the autumn unstable stratification period indicate that further work is needed to improve the model (turbulence?).
Simulation of ice processes sets increased demands on the required field data. Most of the model parameters must be space and time varying. Although field data are at the moment not available in the right quantity and with the necessary precision, the implemented computer model has shown its efficiency to predict the growth and melting of ice on a deep lake.

22. Conclusion
A special version of Delft3D is used for 3D hydrothermodynamic modelling in combination with 2D ice dynamics modelling. Results of calculations for the Teletskoye lake are in satisfactory agreement with the available field data.
It is shown that the density stratification has a huge impact on flow parameters and ice thickness on Lake Teletskoye. The work to improve the hydrothermodynamics model should continue, taking into account an integrated ice module.
The data collection to refine the specific effects of the formation of density stratification of Teletskoye Lake should continue during different hydrological seasons and different weather conditions. It is important to exchange the experiences of such research on other large lakes in Russia and elsewhere in the world.

23. Thank you for your attention