Wadiso 6 User Guide > Program history, purpose and capabilities > Time and Water Quality Simulation Technique

For purposes of time and water quality simulation, the EPANet program has been built into Wadiso. The EPANet program was developed by Lewis A. Rossmann, of the USA Environmental Protection Agency. The program could easily be incorporated, since it was based on the same numeric method used in the original US Army Corps of Engineers’ version of Wadiso, and therefore uses the same data structure as the current version of Wadiso.

For the hydraulic time simulation, a pseudo steady state analysis is executed, assuming that water usage rates, water supply rates, pumping status, and valve status remain constant over a fixed time-period (say one hour), but may change from one time-period to another. The hydraulic time simulation serves as the basis for the water quality calculations, which involve the solution of the equations for the concentration of a dissolved substance in the network, using the Discrete Volume Element Method. The water quality calculations also allow a mechanism for considering the loss or growth of a substance by reaction, as it travels through the distribution system. Reaction can occur, both within the bulk flow and with material along the pipe wall. Water age analysis and source tracing is done through special application of the above water quality calculations.