Journal of Watershed Management Research

     Knowledge of river discharge and water-quality trend can be useful for planning and management of water resources. Due to the fact that the river base flow is supplied by ground water, considering of base flow for managing environmental demand. The Mann-Kendall's test is one of the approaches which is used for investigating of the trend in time series. In this study, the Mann-Kendall's test was used. For separating the base flow from daily discharge data, Hydro Office software was used. Then, after separating the base flow, monthly and annual time series have been formed. Also, the monthly and annual time series of water-quality characteristics including TDS, Ca⁺², Mg⁺, Na⁺, SO4⁺, CL, EC, PH, HCO3 and SAR of Arazkoose hydrometric station were formed to assess the trend of total flow, base flow and Water-quality characteristics data. Meaningful analysis of trend at the significant level of %5 indicates that, there is not any trend in total flow, base flow and Water-quality characteristics except PH in annual time scale. The result also shows that there is a fluctuating trend in monthly time scale.