Assessment of tools for protection of quality of water: Uncontrollable discharges of pollutants.

Selecting an appropriate crisis management plans during uncontrollable loading of pollution to water systems is crucial. In this research the quality of water resources against uncontrollable pollution is protected by use of suitable tools. Case study which was chosen in this investigation was a river-reservoir system. Analytical and numerical solutions of pollutant transport equation were considered as the simulation strategy to calculate the efficient tools to protect water quality. These practical instruments are dilution flow and a new tool called detention time which is proposed and simulated for the first time in this study. For uncontrollable pollution discharge which was approximately 130% of the river's assimilation capacity, as long as the duration of contact (Tc) was considered as a constraint, by releasing 30% of the base flow of the river from the upstream dilution reservoir, the unallowable pollution could be treated. Moreover, when the affected distance (Xc) was selected as a constraint, the required detention time that the rubber dam should detained the water to be treated was equal to 187% of the initial duration of contact.