WATER-QUALITY AND MIXING MODELS FOR TANKS AND RESERVOIRS

Long detention times and improper mixing in tanks and reservoirs may n egatively affect water quality. Mathematical and physical models of mi xing and water quality dynamics may be used to determine how alternati ve designs or operational policies affect the quality of water within and leaving the facility. Three models-a systems model that uses a sim plified representation of the reservoir emphasizing the input and outp ut from the facility, a computational fluid dynamics model based on ma thematical equations, and physical scale models of the reservoir-were applied to the Ed Heck Reservoir, a 4-mil-gal (0.015 x 10(6) m(3)) cyl indrical reservoir in Azusa, Calif. Results of the application of each model are presented graphically along with a discussion of each model 's advantages, disadvantages, and costs.