دبی

Floods cause significant destruction to the economic and social structures of societies each year, resulting in substantial financial and human losses. One of the contributing factors to flooding is urban development around rivers. Due to climate change, Iran has become increasingly susceptible to floods in recent decades, particularly because of its hot, dry, and semi-arid climate. The aim of this research is to conduct flood zoning of the Godar watershed using the HEC-RAS hydraulic model. To achieve this, we first determined the area’s runoff characteristics using satellite images from 2018, a land use map, and the SCS runoff curve number model. Next, we simulated the flood discharge for the basin with return periods of 25, 50, 100, and 200 years using the HEC-HMS hydrological model. Subsequently, we prepared the flood zoning map for the Godar watershed area, encompassing the cities of Naghadeh and Oshnavieh, based on the desired return periods with the help of the HEC-RAS hydraulic model. The results indicate that as the return periods increase, the area of the flood zone in the Godar watershed expands, with increases of 1,255 hectares for the 25-year return period, 1,316 hectares for the 50-year return period, 1,370 hectares for the 100-year return period, and 1,419.7 hectares for the 200-year return period. The results of this study showed that the longer the return period, the larger the area affected by the flood. Studies also show that the HEC-HMS model is suitable for estimating discharge in basins that lack hydrometric stations. The results of this study may be useful in flood management and help reduce the vulnerability of this river to floods.

Nowadays, water is considered as one of the factors for improvement and economic growth of societies. The hot and cold seasons of the year and its comparison with the non-segregation of the hot and cold seasons are 26 years.

In this study, after studying the accuracy of discharge data, electrical conductivity, soluble matter, chlorine, calcium, sodium, magnesium, acidity and sodium uptake ratio of the two stations, it was tried to find appropriate regression relationships between discharge parameter and qualitative parameters. Provide water.

The results showed that the Chehelgazi sub-watershed in cold months, the liner relationship between discharge with electrical conductivity, dissolved solids, chloride and sodium and also the exponential relationship was suitable between discharging with calcium. In warm months for this sub-watershed, the linear relationship presented the suitable relationship between discharge with dissolved solids, electrical conductivity, magnesium, calcium, sodium and the sodium adsorption. Also, the linear relationship was suitable between discharge with dissolved solids, electrical conductivity, chloride and sodium whereas the exponential relationship was better between the discharging with calcium in Khalifehtarkhan sub-watershed. In this sub-watershed, for warm months, the linear relationship was suitable for the relationship between discharge with dissolved solids, electrical conductivity, chloride, sodium and sodium adsorption. The separation comparison of cold and warm months with non-separation showed that non-separation of cold and warm months is not possible the chloride and magnesium estimation (in Chehelgazi sub-watershed) and calcium estimation (in Khalifetarkhan sub-watershed).

using obtained relationships and seasonal changes of surface waters quality, with discharge rate can create modeling water quality, extraction and recovery of water quality data.