Dıscrete-tme dynamıc water qualıty ındex model ın coastal water

Abstract

BACKGROUND AND OBJECTIVES: It is important to develop dynamic water quality index sofware that refected accurately the state of enclosed coastal water quality. This study explored water quality index model sofware including the third-order and daily based discrete-tme transfer functon in Simulink-MATLAB environment to predict the past and future water quality index changes versus discrete-tme by using the data measured approximately once a month. METHODS: A modelling sofware for daily based discrete-tme water quality index was developed to evaluate the polluton level in enclosed coastal water bodies afected by marinas. Measurements were done at three diferent statons near marina entrances in Bucak, Kaş, and Fethiye Bays located at the south western Mediterranean coast of Turkey. The computed water quality index values and the sampled indicators data defned in terms of the deviaton variables were used to identfy the proposed third-order transfer functon parameters. The proposed sofware is applicable for past and future estmates, where inputs may include some missing measurements. The input data are interpolated to estmate daily based inputs by using the developed model in the Simulink-MATLAB environment. For model verifcatons, monthly measured water quality parameters are used. FINDINGS: The sofware including the daily based discrete-tme transfer functon and the input sources was successfully applied to predict past and future water quality index changes with 4.2 percent, 4.3 percent, and 7.1 percent of the absolute maximum errors respectvely in Fethiye, Kaş, and Bucak statons. In three statons studied, seasonal comparison of the enclosed coastal water quality showed that the quality in winter (72±2) is lower than the one (82±8) in other seasons. The past and future daily predictons of water quality index changes versus discrete-tme were realized successfully by using the proposed sofware and the data measured approximately once a month. CONCLUSION: By determining similar transfer functons and selectng some adequate indicators, the sofware proposed can be adapted for quality assessment in other enclosed water bodies