Total dissolved solid and dissolved oxygen modeling, thermocline calculation and applying reservoir salinity reduction scenarios in Shahid Rajaee reservoir using CE-QUAL-W2

Abstract

Iran is not a rich freshwater country. Many dams were constructed in Iran during the last decades. As better operation is always important, discovering different properties of water in the reservoirs is valuable. Shahid Rajaee dam has a large reservoir in the Mazandaran province, Iran. Shahid Rajaee reservoir fits in warm monomictic stratified category. 2012 to 2015 data have been used for modeling temperature, Dissolved Oxygen (DO) and Total Suspended Solids (TDS) in this reservoir with CE-QUAL-W2. Temperature-depth diagrams have been drawn and thermocline characteristics have been determined from the first-year data. Moreover, an operation scenario has been defined. The effect of 20% reduction of the TDS in both upstream rivers or in the major river on the TDS of the reservoir at a specific point. Model9s results show 20% and 14.2% reduction in the maximum value of the TDS time series, respectively and 19.4% and 13.4% reduction in the minimum amount of the TDS time series, respectively. Moreover, IRWQISC Index has been used for determining the reservoir9s water quality. The Index showed a ‘good’ water quality for the reservoir before and after the salinity reduction scenario.