Page - 396 - in Book of Full Papers - Symposium Hydro Engineering

The higher values of COD (sampling point No. 02) indicate water pollution, which is related to wastewater effluents discharged from recreational town. The CTD profiles at sampling point No. 05 for a chlorophyll a, temperature, DO, EC and pH were presented in Fig. 2. For other sampling point, the CTD profile was provided but data are not shown. Fig. 1. CTD profiles at sampling point No. 05 (Winter 2016) As seen in Fig. 2, the increasing of water depth led to decreasing of temperature, DO and pH values. But, the other parameters including turbidity and chlorophyll a showed the different pattern and increased. As seen in Fig. 2, at sampling point No. 05 (deepest point), the thermocline was typically at a depth of 25 to 30 m. The separation of the epilimnion from the hypolimnion is fundamental to lake processes because the stratification typically isolates the hypolimnion from sunlight and atmospheric oxygen. Thus, stratification typically separates the nutrient depleted, slightly less saline and algal enriched epilimnion from the oxygen depleted, nutrient enriched and slightly more saline hypolimnion. Since, the analytical cost involved could be a limiting factor for reservoir quality assessments in developing countries, certain quality indices were used in this study. Fig. 3 shows comparison of WQI evaluations and trophic level for Zayandehrood dam reservoir. Fig. 2. Variations of WQI, NSFWQI and CTSI (2016-2017) The values of WQI (WQI and NSGWQI) are in good agreement. The results indicated that WQI 2-3, NSFWQI from 70-90, while CTSI 35-60 for overall studied period. 4. CONCLUSION Through WQI, NSFWQI and CTSI, it can also be concluded that physicochemical and biological and also trophic characteristic of Zayandehrood dam reservoir water shows sign of well physicochemical and biological characteristic, but mesotrophic (moderately productive) and eutrophic (highly productive) state. 0 5 10 15 20 25 30 35 40 0 5 10 Turbidity (NTU) 0 5 10 15 20 25 30 35 40 4.5 5.5 6.5 7.5 Temperture ( C) 0 5 10 15 20 25 30 35 40 7.5 8 8.5 9 pH 0 5 10 15 20 25 30 35 40 0 5 10 15 DO (mg/L) 0 5 10 15 20 25 30 35 40 0 5 10 15 Chlorophyll a (μg/L) 0 0.5 1 1.5 2 2.5 3 3.5 No. 01 No. 02 No. 03 No. 04 No. 05 Sampling point WQI Boundary line 30 40 50 60 70 80 90 100 No. 01 No. 02 No. 03 No. 04 No. 05 Sampling point NSFWQI Boundary line 0 10 20 30 40 50 60 70 No. 01 No. 02 No. 03 No. 04 No. 05 Sampling point CTSI Boundary line 396