Background: Zayandeh-Rood River is the only perennial river in the central basin of Iran that has fresh water. Water from this source is used for drinking, industrial and agricultural purposes. Drinking water is extracted from upstream portion (upstream of Chamaseman Dam) of Zayandeh-Rood River and therefore its quality is very important. Due to growth of population, industry and other factors, its management needs powerful tools such as Mike model 11 to be able to simulate water quality and quantity.Methods: In this research Mike model 11 was used to simulate water quality and quantity in Zayandeh-Rood River from Tanzimi Dam to Kalleh Bridge (120 Km distance). For this purpose samples were taken at four hydrometery stations along the river during five months. At each sampling location DO, pH, EC, BOD1, 3, 5, 7, NH4, NO3, PO43-, COD and temperature were measured. Then the model was calibrated and its accuracy was investigated. The model results and measurements were statistically compared and their correlation was determined using Pearson correlation test. Also water quality in Zayandeh-Rood River was simulated under two scenarios for the next 25 years. Pearson correlation indicated an appropriate correlation (approximately r=0.9) between the model results and the field measurements.Findings: The findings of this research revealed that the concentration of PO43-, BOD, COD, and NH4.NO3 from Tanzimi Dam to Kalleh Bridge station exceeds surface water standards. The findings for the next 25 years scenarios indicated that due to the population and industries growth, some parameters’ concentration will be increased. This will affect both Zayandeh-Rood ecosystem and purifying drinking water by Baba Shekhali Water Treatment Plant.Conclusion: Also the findings indicated that although DO is within the standard level but it may affects some type of fish production and migration.

Today, flood management is one of the most important topics in river engineering due to reducing the fatality and damages caused by it. Several hydrodynamic models including 1D, 2D, 3D and couple hydraulic models have been developed in the world. One dimensional models have a short computation time and only compute the hydraulic parameters of main river channel. They provide nodetails about inflow or overbank flow and flow changing between river and floodplainds. Dez river in Khuzestan province (Case study) is surrounded by wide low elevation plains. Since the elevation of floodplains is lower than the main channel, when overbank flow occurs, two flows with different velocities and depths should be considered in the main channel and floodplains. In the present study three different modeling including: 1D simulation using existing cross sections, quasi 2D simulation using LINK CHANNELS, 1D-2D modeling with Mike FLOOD, were investigated. The results indicate the quasi 2D model, despite of the limited computational time than 1D-2D model, has an acceptable accuracy in predicting discharge, water level, inflow and overbank flow simulation and reduction in inundation volume, which is compatible with the fact of inundation volume storing in the floodplains and it can separately compute hydraulic parameters of main river and floodplains. In contrast, there is no possibility for 1D model with the original cross sections to simulate overbank flow, discharge and flood volume reduction. It provides the average of hydraulic parameters throughout the whole cross setions. Moreover, flood routing is imposibe to be investigated in this model.

Tsunamis are a series of ocean waves with exceptionally long wavelengths and can be incredibly destructive when they reach coastal areas. These waves are typically triggered by underwater earthquakes, volcanic eruptions, or landslides. The immense force and energy of a tsunami wave can result in widespread devastation, flooding, and loss of life. It is crucial to comprehend the behavior of tsunami waves in order to develop effective early warning systems and strategies for managing such disasters. Numerical modeling has become a valuable tool for simulating the propagation of tsunamis and the processes of inundation. This research focuses on utilizing the Mike3 Flow Model FM for numerical modeling of tsunami waves. The model was tested using the results of solitary wave theory solutions and basic tsunami wave experiments conducted at the hydraulic laboratory of Changsha University in China. Statistical analysis of the numerical simulation results showed that the Mike3 Flow Model FM can provide accurate calculation of complex tsunami wave flows and deliver important results such as tsunami wave height, wave run-up length, flow volume, and temporal-spatial velocity profiles. Notably, the study observed an improvement in the accuracy of the numerical model as the ratio of wave height to water depth (H/h) decreased. Furthermore, it was confirmed that the accuracy of the numerical model in simulating wave velocity (RMSE ≤ 0.14) surpassed its performance in simulating wave surface elevation (RMSE ≤ 2.29), compared to experimental data.