Markov Chain Model for Seasonal-Water Quality Management

An imprecise fuzzy risk approach for water quality management of a river system

“…Most of the water quality input variables are assumed to follow a normal or log-normal distribution, based on literature (Burn, 1989;Takyi and Lence, 1995;Melching and Yoon, 1996;Subbarao et al, 2004;Ghosh and Mujumdar, 2006). Therefore in this section, MCS for imprecise input variables is discussed for normal and lognormal distributions only.…”

“…Uncertainty due to randomness is mainly caused by the random nature of input variables, such as stream flow, temperature etc. This uncertainty is addressed in the models starting with the pioneering works of Loucks and Lynn (1966) (e.g., see Burn and McBean, 1986;Fujiwara et al, 1986Fujiwara et al, , 1987Takyi and Lence, 1995;Sasikumar and Mujumdar, 2000;Subbarao et al, 2004;Ghosh and Mujumdar, 2006;Jia and Culver, 2006;Singh et al, 2007;Sarang et al, 2008). Uncertainty due to imprecision is associated with the objectives and water quality standards of the pollution control agency and the dischargers, which is addressed in Jowitt and Lumber (1982), Sasikumar and Mujumdar (1998), Karmakar and Mujumdar (2006) and Saadatpour and Afshar (2007).…”

A fuzzy risk approach for seasonal water quality management of a river system

“…Apart from imprecision in objectives and standards, randomness of natural variables and model parameters also adds to the uncertainty in water quality problems. Uncertainty due to randomness has been addressed extensively in the models for water quality management of river systems, starting with the pioneering work of Loucks and Lynn [1966] [e.g., see Lohani and Thanh , 1978, 1979; Whitehead and Young , 1979; Spear and Hornberger , 1983; Burn and McBean , 1985, 1986; Fugiwara et al , 1986, 1987, 1988; Tung and Hathhorn , 1988; Ellis , 1987; Takyi and Lence , 1995]. A study addressing uncertainties due to both randomness and fuzziness in water quality management of river systems is relevant from a modeling point of view.…”

“…The problem of seasonal fraction removal of effluent discharges in streams has been dealt with in the works of Boner and Furland [1982], Rheis et al [1982], Eheart et al [1987], Rossman [1989], Lence et al [1990], Lence and Takyi [1992], and Takyi and Lence [1995]. When the optimal fraction removal levels are significantly different across seasons, they could result in notable cost savings compared to a single, uniform fraction removal level all through the year.…”

“…When the optimal fraction removal levels are significantly different across seasons, they could result in notable cost savings compared to a single, uniform fraction removal level all through the year. Innovative seasonal management programs, which consider the dynamic waste assimilative capacity of a river and allow for different levels of waste treatment during different seasons of the year, have been shown to be more cost‐effective than nonseasonal uniform treatment programs [ Takyi and Lence , 1995].…”