ABSTRACT
This chapter focuses on models covering hydrological, hydraulic, and water quality aspects of modelling used in practice. It details the underlying equations and numerical methods that are used to model unsteady flow. The chapter focuses on above-ground flood modelling. It then examines pollutant transport and pollutant transformation. As well as hydraulic and hydrological aspects, some urban drainage flow modelling packages include the ability to replicate real-time interventions and operational rules, and receive live data streams. They have versatile data interfaces with geographic information system (GIS) compatibility and the graphical representation of the system and its response to storms. Wastewater flow varies with the time of day, and during storm conditions, inflow to the sewer system can vary dramatically with time. The representation of unsteady flow is an important component in a sewer-flow software package. Flow surveys provide records of the hydraulic performance of the system, and the conditions that produced that performance.
