In order to investigate the performance of constructed structures in Sardasht watershed, Soil and Water Assessment Tools model for simulation of runoff and sediment during the studied period of 1996-2012 was carried out for two cases of existence and absence of flood control structures. From 2007 onwards by performing watershed operations in these sub-basins, the average runoff rate decreased about 250 l/s for subbasin 1 and 150 l/s for sub-basin 3. This indicates the flood was controlled in these basins. On average, the runoff volume has decreased by 0.25 and 0.15 m 3 in the sub-basins 1 and 3 respectively in the presence of the structure compared to the absence of structures. A daily, Monthly simulation time stage and a continuous-time step restrict the usage of the SWAT pattern for comprehensive, occurrence-based flood simulation. The occurrence of acridities and unexpected projections in numerous sectors of IRAN, also the density on basic conveniences precious by mass growth, has owing to a broader difference in deliberation to the problematic of water straight in the alliance. Calibrating a hydrologic model of Sardasht Basin. Using SWAT. Subjective Workload Assessment Technique (SWAT) is a multidimensional scaling method designed to assess time load, mental effort load and stress load. According to the results of Mann-Kendall Test, Watershed management in the Sardasht basin for flood control and runoff can be considered acceptable. Before the watershed operation, the occurrence of runoff with the probability of 80% was zero, which after the operation, the probability of occurrence was reduced by 60%, indicating a positive effect construction of flood and sediment control structures in the Sardasht basin. The results of the hydrological regime curve show that the changes in the monthly runoff ratio to the average monthly runoff before the watershed operations had been more. Due to the limitations, current Soil and Water Assessment Tools simulations in tropical and subtropical regions face a series of problems related to relative humidity, water balance and sediment. Soil and Water Assessment Tools model is also used to estimate the maximum daily flow rate.

Reuse of refined sewage with two goals of providing more water and protecting the environment from pollution is one of the solutions to water supply problems and one of the potential sources for irrigation in agriculture. The aim of this study is to evaluate the possibility of effluent disinfection using a sand filtration system to reduce microbial contamination with potassium permanganate powder. Each experiment was performed in 3 replications. The results of this study showed that adding 5 weight percent of potassium permanganate powder to silica sand eliminates the removal efficiency of total coliform and focal coliform to 99.99%. By reducing this percentage to 0.15 weight percent of potassium permanganate powder as the optimal amount, the results were the same. Also, the addition of 15 weight percent of potassium permanganate powder with silica sand increased the amount of opacity removal and the removal efficiency was 95.5%. As measured parameters were less than environmental standards. According to the results, the performance of potassium permanganate powder with silica sand is better than other treatments.

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