The vertical distribution of temperature and water is calculated for natural soils as well as for artificial seal materials. For each vertical grid box a different soil material can be chosen in order to simulate different urban soils. The flow of water inside natural soils is calculated using the formulae from Clapp and Hornberger. The hydraulic equations include a sink term for water uptake by plant roots. The thermodynamic properties of the soil are estimated by means of the actual water content.

Water bodies are represented as a special type of soil. The calculated processes inside the water include the transmission and absorption of shortwave radiation inside the water. No second energy balance is used for the ground surface of the water pool, so that heating of shallow systems is lower than under real conditions where the main source of energy is the convection from the water ground surface rather than the absorption of radiation. In addition, no turbulent mixing is included in the model so that the use is restricted to still waters (e.g. lakes). The water parameterisation will be extended to turbulent mixing (oceans) later on. Special water usage (e.g. fountains) cannot be calculated with the model at the moment.