Need: When building a sewer system network model (e.g. For Drainage Area Plans) one of the most time consuming and difficult task is defining the catchment areas otherwise known as subcatchments and the percentage of impermeable surfaces within them.
Challenges: The task of creating subcatchments involves the division of complex network catchment into smaller manhole based subcatchments. A complex set of rules is used to define divisions and determine impermeable areas. This can be an extremely time consuming task when carried out using traditional manual methods.
Solution: A toolbox was created which uses set inputs and applies hierarchical set of business rules to generate model ready subcatchments. Analysis is undertaken to build a subcatchment based upon all roofs, roads, paths, property boundaries and any other semi/ impermeable areas within a manhole drainage area. Subcatchments are automatically measured and codes assigned creating a ‘network model ready’ file
- Time savings of >80% – the model rather than the modeller generates subcatchments
- Improved modelling –more detailed catchments providing a better representation of run-off
- Consistency – Judgement is removed so all catchments based on the same rules