نشریه فناوری های پیشرفته در بهره وری آب
سال دوم شماره 4 (زمستان 1401)

Every year, the occurrence of heavy rains in the flood-prone basins of the country leads to the occurrence of floods and the resulting damages. Therefore, accurate prediction of rainfall is of great importance to take preventive measures. Therefore, rainfall forecasting is one of the most important issues in the field of water resources management. So far, various methods have been used to predict rainfall. Advanced hydrological research in short-term weather forecasting is uncertain and its impact is still being investigated and understood. The concept of connecting the hydrological model (WRF-Hydro) with the atmospheric model (WRF) is expected to reduce the uncertainties related to the spatial and temporal distribution of storm events, especially for areas with complex characteristics.In this study, the WRF/WRF-Hydro model was evaluated in order to predict 4 rainfall events that resulted in floods. In precipitation simulations, this model was underestimated and the model provided better results in coupled mode. ERA5 data was used to run the model, and these data had a good performance for the model in the mentioned field. Also, Lin, Thompson, and WSM6 were used to configure the model, and according to the error evaluation criteria of RMSE and NSE, all three of these schemes performed similarly.

The objective of this study was to investigate the effects of combined stresses of irrigation salinity and nitrogen fertilizer on the yield and yield components of millet plant. The field experiment was conducted as a split plot experiment in a randomized complete block design with three replications at the research farm, Faculty of Agriculture, Ilam University during growing season in 2022. Treatments included four levels of irrigation salinity including 0.63, 3, 5, and 8 dS/m (S1, S2, S3 and S4) as main plots and three nitrogen fertilizer levels including; 100, 75 and 50 % of fertilizer requirement (N1, N2 and N3) as subplots. The results showed that the effect of salinity stress was significant on leaf/stem ratio and panicle length at P<5% and for the rest of the yield components at P<1%. Also, the effect of different nitrogen treatments was significant on all components yield of millet, except leaf/stem ratio, panicle length and plant height. The interaction effect of salinity and nitrogen stress was significant on thousand seed weight, biomass weight, yield and harvest index at the at P<1% and had no significant on leaf/stem ratio, panicle length and plant height. The highest millet yield was 3.76 tons per hectare in S1N1 treatment and the lowest yield was 2.53 tons per hectare in S4N1 treatment.

One of the effective methods to reduce the kinetic energy downstream of hydraulic structures are the aprons. The horizontal aprons is one of these structures in the river that are often used downstream of stilling basins. At the time of execution, the apron and the riverbed are at the same level but when there is a flow in the boundary between the connection of the river bed and the aprons, scouring occurs, which causes the destruction of the apron and there is a possibility of destroying other water structures. In this research, using Flow 3D software, different scenarios were simulated for five Froude values of 0.32, 0.3, 0.25, 0.2, and 0.15, three Manning roughness coefficients of 0.025, 0.02, and 0.014 per particle diameter of 1.8 mm for horizontal aprons. In this numerical model, the graph of scouring depth changes in relation to Froude numbers in different roughness coefficients, the effect of Froude numbers on the location of the scour hole for different roughness coefficients of the horizontal aprons, the shear stress changes in relation to the length of the horizontal aprons with different roughness coefficients and different Froude numbers, as well as Erosion changes with respect to the length of the horizontal aprons were calculated with different roughness coefficients and different Froude numbers.

In the sediment washing method under submersible flow, the volume of the discharged sediments depends on various parameters, which can be referred to the depth of the water inside the tank, the depth of the water inside the pond, the output flow from the lower discharger, the size and type of accumulated sediments inside the tank. did To check the mentioned parameters in this research, a physical model with a length of 1 meter, a width of 1 meter and a height of 1.10 meters and by performing various tests using 2 water heights inside the tank, 3 water heights inside the pond and with 3 types of sediment granulation (in total 18 experiments) were investigated and studied. The results of this research show that in sediment washing under pressure, when the lower discharger returns for sediment washing, a sediment washing cone is formed in front of it. The dimensions of the formed sediment washing cone depend on the discharge from the lower discharger, the height of the water inside the tank and the diameter of the sediments accumulated inside the tank, so that the measurement results show that in order to keep the height of submerged water constant, the height of water inside the tank increases. It increases the volume and length of the sediment washing cone. Also, for a fixed water height inside the tank, increasing the submerged water height increases the volume and length of the sediment washing cone.

In areas with dry and semi-arid climates, underground water is one of the main sources of water supply for agriculture, industry and drinking. The aim of this research is to investigate hydrodynamic coefficients, plain balance and aquifer thickness in the study area of Kermanshah through aquifer simulation using MODFLOW model. In this method, first the conceptual model and then the numerical model were built in two steady and unsteady states, then it was calibrated and validated. The results show that the maximum thickness of the aquifer in the north and northeast of the plain is about 160.96 meters, and the lowest thickness is 118.14 and 120.69 in the southwest and west of the plain, respectively. Also, the coefficient of hydraulic conductivity varies between 0.09 and 40 m/day and the coefficient of specific yield varies between 1 and 35%. Balance calculations showed the negative water balance in the western and southwestern areas of the plain and the positive balance in the northern, northeastern, and southeastern areas.

This research was carried out to investigate the physical and chemical properties of the soils obtained from dredging of the drainage drains in Abbas Irrigation channels in Ilam province. The area encompasses 16 thousand hectares. In this study sampling was carried out from two major branches. The drainage No. 1 with 21 km length, is flooded to the Rafahyeh river and drainage No. 2 with 5 km length is flooded to the Chikhab River. Sampling was done from drainage soil, dredged soil and the arable land around drainage. A comparison was performed between the three regions of drainage floor area, drainage agricultural land and dredged soil. Soil physico-chemical properties such as particle and bulk density, potassium, magnesium, sodium, calcium and phosphorus, carbonate and bicarbonate, sodium absorption ratio, exchangeable sodium percentage, organic matter, organic carbon, cation exchange capacity, sulfate, base saturation percentage and nitrogen. The results showed that the amount of potassium in dredged soil is more than recommended for soil. Phosphorus concentration was also higher than recommended for soil. Sodium, magnesium and calcium was lower than soil recommended levels. Due to the presence of calcareousmaterial,the amount of limein soils washigh and the amount of gypsum was high as well, due to the warm and dry climate and low rainfall. Soil pH of the region was mostly higher than 7 so they are categorized as alkaline and semi-alkaline soil. The studied soil is classified as saline soil due to high electrical conductivity.Soil texture was sandy clay loam.