Robert P. Bukata, John H. Jerome, Alexander S. Kondratyev, Dimitry V. Pozdnyakov, Canada) Bukata, Robert P. (National Water Research Inst., Ontario, Canada) Jerome, John H. (NWRI/CCIW, Burlington, Ontario, USA) Kondratyev, Alexander S. (Central Washington University, Ellensburg, Washington, Russia) Pozdnyakov, Dimitry V. (University Emb, St. Petersburg