Department Surface Waters - Research and Management


Simstrat is a one-dimensional physical lake model for the simulation of stratification and mixing in deep stratified lakes. The model was introduced by Goudsmit et al. (2002) and is under continuous development. It has been successfully applied to lakes with different physical properties. For a few examples, see the key publications below.

Simstrat is operationally applied to all larger lakes and a selection of smaller lakes in Switzerland. The results  are regularly updated, and simulated temperatures for the current year are compared to long-term means and ranges.

The Simstrat code is freely available on Github. Simstrat is also included in the R package LakeEnsemblR that supports ensemble modelling with a range of different one-dimensional lake models.

Main properties of the Simstrat model

  • 1-dimensional physical lake model (resolving the vertical dimension)
  • simulates temperature, stratification and ice cover in lakes and reservoirs
  • optional coupling to AED2 for simulating biogeochemical processes
  • k-ε model for turbulent mixing
  • includes energy transfer to mixing via internal seiches
  • inflows can be added at specified depths or with density-dependent intrusions
  • variable lake levels
  • programmed in object-oriented Fortran 2003
  • parameter estimation using PEST is implemented

Key publications

Bärenbold, F.; Kipfer, R.; Schmid, M. (2022) Dynamic modelling provides new insights into development and maintenance of Lake Kivu's density stratification, Environmental Modelling and Software, 147, 105251 (15 pp.), doi:10.1016/j.envsoft.2021.105251, Institutional Repository
Råman Vinnå, L.; Medhaug, I.; Schmid, M.; Bouffard, D. (2021) The vulnerability of lakes to climate change along an altitudinal gradient, Communications Earth & Environment, 2, 35 (10 pp.), doi:10.1038/s43247-021-00106-w, Institutional Repository
Gaudard, A.; Råman Vinnå, L.; Bärenbold, F.; Schmid, M.; Bouffard, D. (2019) Toward an open access to high-frequency lake modeling and statistics data for scientists and practitioners - the case of Swiss lakes using Simstrat v2.1, Geoscientific Model Development, 12(9), 3955-3974, doi:10.5194/gmd-12-3955-2019, Institutional Repository
Schmid, M.; Ostrovsky, I.; McGinnis, D. F. (2017) Role of gas ebullition in the methane budget of a deep subtropical lake: What can we learn from process-based modeling?, Limnology and Oceanography, 62(6), 2674-2698, doi:10.1002/lno.10598, Institutional Repository
Gaudard, A.; Schwefel, R.; Vinnå, L. R.; Schmid, M.; Wüest, A.; Bouffard, D. (2017) Optimizing the parameterization of deep mixing and internal seiches in one-dimensional hydrodynamic models: a case study with Simstrat v1.3, Geoscientific Model Development, 10(9), 3411-3423, doi:10.5194/gmd-10-3411-2017, Institutional Repository
Råman Vinnå, L.; Wüest, A.; Bouffard, D. (2017) Physical effects of thermal pollution in lakes, Water Resources Research, 53(5), 3968-3987, doi:10.1002/2016WR019686, Institutional Repository
Fink, G.; Schmid, M.; Wüest, A. (2014) Large lakes as sources and sinks of anthropogenic heat: capacities and limits, Water Resources Research, 50(9), 7285-7301, doi:10.1002/2014WR015509, Institutional Repository
Goudsmit, G. -H.; Burchard, H.; Peeters, F.; Wüest, A. (2002) Application of k-ϵ turbulence models to enclosed basins: the role of internal seiches, Journal of Geophysical Research C: Oceans, 107(C12), 3230 (13 pp.), doi:10.1029/2001JC000954, Institutional Repository