Variety is the spice of modelling!

There are many different modelling approaches that can be used in hydrology, which is quite interesting and useful as it brings more options for modellers to choose from according to their need. So it’s pretty cool in that sense but it is very important to not get so carried away so that the main purpose is lost or the quality and usability are downgraded. And it often more logical to seek the simplest model that can efficiently address the problem of interest.

It is quite useful to consider three different modelling dimensions (Watts, 1997 cited in Watts, 2010)

1. Theoretical complexity
2. Spatial resolution
3. Temporal resolution

Today we are going to investigate different models with different theoretical complexity levels.

Three models can be considered while considering the theoretical complexity level. From simple models to more complex are Empirical models, Conceptual models, and physically based models. 

Empirical models are the simplest and describe how the system behaves without getting into details of the physical processes. These simple models usually use statistical data. 

Conceptual models are a bit more complex. These models represent a simplified behavior of catchments on perceived behavior of the catchment rather than getting into details of the physical characteristics of the catchment. For example a conceptual catchment model thinks of the soil medium as a bucket that accommodates recharge for groundwater when it reaches its full capacity.

Next level of complexity is for physically based models. These models try to represent the physical process of water movement in the catchment. This method uses the physically based equations and often are parameterized by the catchment characteristics such as soil properties that are measurable in the laboratories (Watts, 2010).

Join me on the next post where we explore the spatial and temporal resolutions. After having gained some information on the available approaches we shall see which one is more appropriate when looking at water availability under the impacts of climate change. 

So long