Determining the Eutrophication State of Ecbatan Reservoir using Carlson Index

Reservoirs are vital and necessary resources of potable water. Different sectors such as agriculture, industry and fishery are dependent on these resources which need high quality water. Water quality is mainly evaluated using different parameters such as pH, temperature and turbidity which are easily measured. Also there are some more complicated parameters such as eutrophication degree of a water body. This study was accomplished to investigate the trophic state of Ecbatan reservoir in dry and wet seasons. Water sampling was accomplished in July and January to compare the trophic state of the reservoir in two critical situation of a hydrologic dry year. 15 stations were selected in different points of the reservoir. Different parameters of water quality were measured such as temperature, pH, Secchi Disk (SD), Total Nitrate (TN), Total Phosphate (TP) and chlorophyll-a (chla). The trophic state was estimated for all stations using Carlson index. Results of the study show that trophic state of the lake is mild mesotrophic in July and acute mesotrophic in January. Also Phosphorous is the limiting nutrient in this reservoir. This research showed that eutrophication is a serious problem in Ecbatan reservoir and managerial strategies are required to prevent water quality deterioration.