RIBASIM supports various levels of water quality related modelling options which are carried out after the water allocation computation:

• Flow composition. The sources of the river and canal flows are computed e.g. percentage from catchment runoff or a specific reservoir or irrigation drainage.

• Basic water quality. Defined substances are routed thru the network and the concentrations and mass balances are computed e.g. biological oxygen demand (BOD), total nitrogen, total phosphorus, bacteria and toxic substances. Substance retention is defined in the network.

• Biological and chemical processes. The standard Delft water quality model DELWAQ (including Waste load model) is part of the standard RIBASIM software and is used if an advanced in-depth modelling of chemical and biological processes is required.

 Status of Sabarmati river at Ahmedabad (Gujarat India)

Industrial discharge (China)

Urban drainage canal (Jakarta, Indonesia)

Water hyacinth Chao Phraya River (Thailand)

Waste water treatment plant Chao Hu China