مجله مهندسی آبیاری و آب ایران
پیاپی 53 (پاییز 1402)

Understanding flood phenomena and estimating flood potential play an important role in flood management and forecasting in any region. Due to the flooding of Mahneshan-Angoran basin, located in Zanjan province, Central Iran, in this study, the effective factors on flooding of this basin were investigated. For this purpose, first the basin curve number map was created by combining soil maps, land use, Digital Elevation Model and Look up table involving GIS environment. Then, using AHP Hierarchical Analysis method and based on the combined effects approach, appropriate weights were assigned to each of the slope factors, slope direction, land use, curve number, branch ratio, drainage density, precipitation, basin length and basin lithology. A flood risk map was prepared from the overlap of the weighted layers in the GIS environment. The results of AHP method showed that the highest weight among the effective factors is equal to 0.326, which belongs to the factor of the basin Curve Number. Other effective factors are: land use, slope, rainfall, drainage density, branching ratio, basin length, slope direction and lithological factor, which respectively have weights affecting flooding equal to 0.174, 0.142, 0.118, 0.090, 0.051, 0.042, 0.042 and 0.016. According to the obtained flood plan, it was observed that the western parts of the basin have a higher risk than other parts of the basin due to higher altitude and more rainfall, which is itself a proof of the accuracy of the calculations.

Piano key weir is a new form of nonlinear overflow that has been considered in recent years to increase the discharge coefficient and water storage in dam reservoirs, as well as flood discharge. The aim of this study is to investigate the effect of the angle of the side walls of the weir in the horizontal, vertical directions and simultaneous in both directions on the discharge coefficient. Hydraulic performance of 8 geometric parameters (W: weir width, Wi: inlet key width, Wo: outlet key width, P: weir height, L: weir length, Ht: water surface depth, α: horizontal wall angle, β: vertical wall angle) on discharge coefficient Using 6 models of PVC material, by labeling P αβ was tested in a laboratory flume. The experiments were performed on a rectangular piano key weir as a control and a trapezoidal piano key weir with P 07 10, P 90 13, P 03 90, P 03 11 and P 05 05 side wall angles. A total of 1598 data were measured to investigate the discharge coefficient and 1584 data for water level profiles. Based on the high flow results, the discharge coefficient of the trapezoidal piano key weirs in the P 05 05 model with a value of 41.6% is higher than the rectangular piano key weirs. In these models, the most influential factor on the discharge coefficient is the dimensionless geometric parameter L / W, which is based on the method of analysis of eviews statistical software by the discharge coefficient equation.

Scouring at the place of submerged pipelines under the effect of eddy currents around the pipe passing through the riverbed leads to the settlement and failure of the pipeline as well as the penetration of the fluid passing through the pipe into the stream. Therefore, efforts to reduce these risks and their effects are always the attention of researchers and engineers. In the current research, scouring and sedimentation around the pipe and its surrounding bed under the effect of a protective plate at different positions and heights have been investigated and analyzed using Flow-3D. A comparison of the simulation results of the present research with the laboratory results showed that the used numerical model with the statistical index R2=0.96 has an acceptable ability in simulating the mentioned phenomenon. Also, the results showed that by installing a plate with a height of H=1.25D (D is the diameter of the pipe) and at a distance of 0.5D downstream of the pipe, the scouring depth under the pipe decreases by 60%, and also the average level of the bed in the upstream area increases by 82%, which is the most optimal state among different downstream positions. The optimal state of the plate in the upstream corresponds to the height of H=0.75D and at a distance of 1.5D, which not create scouring, and the average level of the bed between the pipe and the plate in the upstream has increased 4.9 times compared to the state without the plate.

The study of fluid motion using experimental and analytical methods is one of the scientific fields that has been considered today. With the advent of computer methods, humans have been able to study more complex phenomena. One of the scientific fields in which many advances have been made is computational fluid dynamics. In fact, computational fluid dynamics studies fluid behavior using new technologies and computational capabilities. In fluid dynamics, stagnation pressure (Pitot pressure) is the static pressure at a stable point in the fluid flow at a stable point, the fluid velocity is zero. In the present study, the stagnant pressure at the edge of the flow separating blade in rectangular channels was investigated in 18 models with different opening angles, baffle shapes and baffle arrangements. The modeling results show that the lowest stagnant pressure in the channel is created with an opening angle of 45 degrees and with convergent mode,and the maximum pressure was created in the channel with an opening angle of 60 degrees with the zigzag arrangement type.

Manning's coefficient is one of the main factors that lead to energy loss in channels and rivers which have a very important role in water level in cross-sections of rivers. There are several methods that suggested by various researchers for estimating Manning's coefficients which are mostly based on experimental tests. In river hydraulic, flow resistance or Manning's coefficient is changing because of bed mobility. In this case, a flow resistance formula cannot be used directly without any information about changes of flow resistance coefficient, in different situations of flow and sediment processes. Babolroud- River of mazandaran selected for this study. So, results of various empirical methods obtained to find out this coefficient using field survey and characterization of rivers such as cross-sections, soil materials of river bed and banks, then results compared with observed and simulated data of river flow. According to the obtained results, koven's method, which has the lowest relative error percentages of 6.17% and 3.46%, and also the lowest root mean square error of 2.7 and 3.2, respectively, in Pashakola and Quran Talar hydrometric stations, is suggested as the best method for estimating Manning's coefficient in this river. After kowen's method, Jarrett's method with relative error percentage of 10.11% and 5.41%, and also the root mean square error of 4.5 and 4.5, respectively, is chosen as the second method for determining Manning's coefficient in Pashakola and Quran Talar hydrometric stations.

With the advancement of science, human societies use transmission pipes to transport water and other fluids from the bed of seas, rivers, streams and natural drains. If pipelines pass through rivers and seabeds on their way, great care must be taken in their design. The main purpose of this study is to investigate the effect of the insertion depth of the shield on the pipeline scour at different distances of the pipe from the bed. This study was carried out in a flume with the length of 10 m and the width of 30 cm. Experiments were conducted under clear water condition (u/uc=0.95). Uniform sediment with a median diameter of one millimeter (D50=1 mm) was considered. In this research, a PVC pipe with an external diameter of 2.5 cm was used. The distance of the pipe from the bed (G) was considered based on a coefficient of the pipe diameter (0, 0.25, 0.5, 0.75, 1). Also, the insertion depth of the shield (Dw) was selected according to a coefficient of the pipe diameter (0, 0.25, 0.5, 0.75, 1, 1.25, 1.5, 1.75 and 2). The results of the experiments showed that in the case that the shield was not used, with the increase in the distance between the pipe and the bed, the maximum scour depth under the pipeline decreases.

Intake canals of off-stream reservoirs, play a key role in achieving reservoir goals. Chahnimeh reservoirs have been constructed to store and use water optimally for drinking, agricultural development and play a complementary role to flood control. The Sistan plain in the southeast of Iran is highly dependent on surface water resources. The HEC RAS model is a well-known one-dimensional software for flow and sediment simulation. In this study, HEC RAS 6.0.0 was used to simulate sedimentation in feeder 2 canal under maximum conditions as well as minimum water level conditions of Chahnimeh reservoirs. Flow simulation in the model was performed quasi-unsteady using the standard step-by-step method by a flood hydrograph with a volume of one billion cubic meters. According to the simulation results, in maximum water level Conditions, Feeder 2 canal Sedimentation volume is equal to 54,200 m^3 which increases the bed level by 4.1m. Also, in minimum water level Conditions, sedimentation is equal to 52,700 m^3, which increases the bed level by 3.84 m. Comparison of the results in the two scenarios shows that in the case of maximum water level, volume of sediment per unit of length of Sistan River is equal to 6.5 m^3⁄L_River while in minimum water level volume of erosion is equal to 2.2m^3⁄L_River of Sistan River. Although feeder 2 canal in minimum water level conditions increases the inflow from the Hirmand river due to the decrease in the river bed level of sistan river but will act as a sedimentation canal in all conditions.

Water management in water basins requires information of some facts and full acquaintance of basin conditions, which is problematic due to the deficiency of data collection stations in the country. One of the most suitable methods for flow simulation is the use of hydrological models. In this study, in order to simulate runoff caused by precipitation and to investigate the apparatus of runoff formation and outflow at the outlet of Shahid Rajaei Dam basin located in Sari, the HBV-Light model was used. The purpose of evaluating the stochastic method is to estimate the model parameters and reduce the uncertainty. The length of the daily statistical period was the variables of temperature, precipitation, runoff and evaporation from 1981 to 2015. The Monte Carlo random method was used to estimate the appropriate parameters for the study area. For a consistent assortment, the values of the parameters with a relatively good coefficient of determination were used in the validation section. Finally, the results show the good aptitude of the model in simulating runoff in the study basin. The values of coefficient of determination 0.87, Nash coefficient (NS) equal to 0.66 in the range of good evaluation and RMSE equal to 0.26 in the validation period indicate this issue. In the analysis of uncertainty caused by model parameters, K1, K2 and UZL parameters were identified as the most sensitive in the model reaction subroutine. Therefore, the results showed the importance of accurate determination of water and soil parameters affecting subsurface runoff.

One of the major issues in arid and semi-arid areas, namely Iran is water scarcity. Therefore, in the present study, the use of rainbow trout effluent in the sprinkler irrigation system for potato cultivation was investigated for three years (2019-2021). This research was conducted in the form of a factorial experimental format based on a completely randomized design with three replications. The investigated factors include irrigation at two levels, A1 (irrigation with well water) and A2 (irrigation with fish effluent), as well as washing the leaves of the plant in four levels they are Before applying fish farm effluent to the leaves, they were washed for ten minutes with fresh water (B1), after applying fish farm effluent to the leaves, they were washed for ten minutes with fresh water (B2), The leaves were washed with fresh water for ten minutes both before and after applying the fish farm effluent to them (B3) and the leaves were not washed at all (B4). The results of this research show that the highest amount of yield, the number of stems per plant, the fresh weight of shoot, the percentage of tubers 80-120 grams, the percentage of tubers 120-150 grams, and the percentage of tubers larger than 150 grams were 565.983 grams per pot, 7.417, 57.608, 32.950, 7.850, 6.039 respectively. These highest amounts were all the results of applying A2 .

In this study, the area under cultivation, average irrigation water and orchard yield were determined by field studies by researchers. Indicators of water consumption, virtual water, water productivity, virtual water consumed and water consumption intensity were obtained. Then, using irrigation planning, the amount of irrigation water was evaluated for the conditions of reducing water consumption in orchards. The best conditions for each crop were selected based on the results obtained and compared with the current conditions. According to the results, in most garden products, it is necessary to reduce water consumption compared to the current situation. The largest decrease was observed in peach, apple, nectarine and grape crops. The difference between water consumption for these products in the current and optimal conditions was 0.7, 6.4, 6.3 and 5.7 million cubic meters, respectively. The lowest difference between water consumption in the current and optimal conditions was determined in pomegranate and pistachio products with a difference of 0.12 and 0.35 million cubic meters. The average of virtual water consumed by horticultural products in Alborz province in the current situation is 0.0133 million cubic meters, which in the optimal case decreased to 0.0109 million cubic meters. Therefore, with the reduction of water consumption in orchards, the intensity of water consumption decreases from 0.33 to 0.26. This will save 19% of the province's water resources.

In the current situation of the country, which is facing numerous droughts, simulation of the performance of different crops in water shortage conditions has attracted the attention of modelers. Among these models, WOFOST has been used in predicting crop yield in numerous researches.In this research, the development of the WOFOST model under the Python language along with how to simulate the performance of major crops in the Tajan plain watershed including rice, wheat, oilseeds, grain corn and tomato during the years 2014-18 was examined. Based on this, at first, the annual crop yield was received from the Agricultural Jihad Organization and the simulation results were compared with these data. The crop yield simulation results of the PCSE Python version showed very little difference with the reported values, so that the RMSE and nRMSE results were reported in the range of less than 10%, which puts it in the good to excellent range. which proves the power of PCSE model in simulation. On the other hand, the results of the T test at the 95% probability level showed that in most of the products, no significant difference was observed between the simulation and observation values, which shows the advantages of theThe outputs of both WOFOST and PCSE models are completely consistent. Comparing the results also shows that there is a small difference between the simulated and observed values. Therefore, it can be concluded that the PCSE model has the ability to simulate the performance of products.

Aloe vera L. is one of the medicinal and perennial plants, which is cultivated in arid and semi-arid regions. Although this plant is relatively resistant to lack of irrigation, but in the conditions of commercial cultivation, it is necessary to pay attention to the supply of irrigation water during the growing season. Due to that, the present study was conducted in order to investigate the effect of the amount of irrigation water (I1: 50, I2: 75 and I3: 100% of water requirement) and Trava 2020 superabsorbent (A1: zero, A2: 5 and A3: 10 grams per kilogram soil) on the yield and yield components of Aloe vera. These treatments were applied in three replications and the crop was harvested in two times include: autumn 2020 and spring 20201. The experiment was carried out in a research farm in Omidiye city with longitude 30°37’ and latitude 49°49’. Leaf length, leaf width, leaf weight, number of leaves and number of offset in the second harvest were 26.8%, 25.1%, 25.5%, 27.0%, 24.1% and 17.5% more than the first harvest. Increasing the consumption of superabsorbent caused an increase in leaf length. The difference between the leaf length in two treatments A3 and A2 was about 3.4% and between two treatments A3 and A1 was about 6.9%. With the increase of superabsorbent consumption, the leaf width increased so that its value reached from 79 mm in A1 treatment to 83 mm in A3 treatment.

Floods are one of the most common natural disasters, known as a major catastrophe, affecting various parts of the world, even in developed countries, which cause billions of dollars in damage to infrastructure annually and hundreds of lives. They lose themselves. Preparation of flood zoning maps for different return periods is one of the common methods used to show the potential for flood hazards. One of the basic solutions to control and reduce the destructive effects of floods is to identify floodplains in watersheds. The purpose of this study is flood zoning and simulation of hydraulic behavior of Dafeh sub-basin in Rafsanjan watershed using HEC-RAS software. The study area of ​​Defeh sub-basin is located in Rafsanjan region in the geographical coordinates of 55 1818 55 to 39 191957 east longitude and 151 2222 29 to 38 3939 عرض north latitude. The circumference of the region is 746.6 km, the maximum and minimum altitudes of the region are 4499 and 1450 meters, respectively. In this study, Google Earth and GIS software to prepare a digital model of altitude and then after sorting and formatting the input data of the HEC-RAS model for flood zoning and simulation of river hydraulic behavior And management scenarios were used. The results obtained in this study show that the amount of discharge and volume of floods from rainfall with a return period of 25 years equal to 68.1 cubic meters per second and 1150.6 thousand cubic meters.

Drought leads to water scarcity for people and potentially causes challenge for many countries. Its effects does not just limit in arid and semi-arid This research tries to take one step identifying impacts of meteorological drought on groundwater resources in Haraz Watershed downstream region. In order to evaluate meteorological drought were used SPI index according to data which has been extract from 15 rain-gauge station in six time scale of 3, 6 9 12, 18 and 24 months and in order to evaluate changes in groundwater level according to data has been extract from 35 water wells pizometric level with mutual 29 years priod (1985-2013). All stations experienced drought event. Major drought was near to normal, moderate and less occurred sever and very severe drought in the region. In this study it was found that drought affected with a 3-month delay on groundwater resources. In this study, the highest correlation between standardized precipitation index and average groundwater level in 24 months' time scale in rain-gauge stations Nemarestagh, Miandasht and Babolsar at 95% and in the other rain-gauge stations is significant at 99% level. Regression relation between the mean level of the water table and SPI-24 of rain gauge station showed that the between study area rain gauge station, Sorkhrood station greatest effect is explained by a factor of 42.3 percent of the variance at the mean level of the water table in this study area allocated and 57.7 percent was affected by other factor.

Examining the current situation of agriculture shows that despite the potential to increase the agricultural products, due to the lack of a proper management system, the possibility of optimal use of water and soil resources has not been possible. In this regard, it is necessary and necessary to examine the solutions for optimal use of water through a review of the allocation of water resources and its management. In this research, using the evaluation of the water footprint index, the water footprint of alfalfa, watermelon, fodder corn, wheat, rapeseed, cucumber and onion products in Razavi Khorasan, Kerman and Isfahan provinces were calculated and compared with each other to determine Which province has more favorable planting conditions for each product from the point of view of the water footprint index.Uneven distribution of rainfall and lack of water in many parts of the world have created many problems for the production of agricultural products and even the provision of safe drinking water. As some scenarios predict, by 2025, 60% of the world's regions will experience water stress due to the increased use of water resources. Most of these regions are located in Africa, Asia and Latin America.Therefore, due to the lack of proper time and place distribution of rainfall, agricultural management to increase the efficiency of water consumption is much more difficult than in countries with favorable water conditions.

Water is one of the most important issues in the world, which plays a significant role in people's lives. Due to progress in all parts of the community, especially advances in socioeconomic, industrial and socioeconomic sectors, as well as the growth of the population, the need for water has increased. A general look at recent experience and global experiences suggests that the limitations of water resources are not due to lack of resources, but because of lack of resource management. In this regard, management of water resources in dry and semi-arid areas such as Sistan, which faces a drought, is very important. Therefore, in this study, using multi-index gray technique, the evaluation and prioritization of water resource development plans has been addressed with regard to various management aspects. According to the results, based on four economic, social, technical and environmental approaches, one of the most important findings of the research from the experts' point of view is the reduction of water losses (reduction of evaporation by 50%), irrigation efficiency of 50% in agriculture and reduction of irrigation losses (reduction of evaporation to 30%) are ranked first to third respectively. Water transfer to Zabol lands is also a priority. Also from the farmers' point of view, the most important results of this study are water loss reduction (evaporation reduction of 50%), irrigation efficiency of 50% in agriculture and irrigation efficiency of 70% in agriculture, respectively, in the first to third priority respectively.

Rivers, as one of the available surface water resources that are exposed to pollutant discharge have extra importance. In this study, while monitoring and simulating the process of qualitative changes in the 8 km reach of Neka River by using the QUAL2Kw, the effects of dams, natural flow waterfalls and bed stabilization structures were evaluated. For this purpose, twice qualitative sampling and local visits were performed. Then, the initial model was prepared and the estimation of data defects, the model was calibrated and validated. evaluation of trend changes in parameters showed that all parameters are within the standard reach and the river has a high self-purification capacity. trending of dissolved oxygen changes showed that the concentration of these parameters was close to saturation, which was due to the favorable hydraulic conditions of the river for aeration rate and the presence of numerous natural and artificial waterfalls in the river. Although the pH value was within an acceptable range, some sections were close to the saturation range because of the release of carbon dioxide due to waterfalls in the flowing water, which the model simulated these effects well. Also, the existence of small dams and creation of a wetland behind these dam Cause to bacteria have been given more time to decompose organic matter, which has increased the alkalinity and pH reach. The results analysis and error indicators showed that the QUAL2Kw model has a good accuracy in simulating the quality of Neka river.

The accumulation of heavy metals in the wetlands may cause significant damage to the environment. In this study, an experimental study was performed to reduce the amount of heavy metals using inexpensive and available materials. For this purpose, three metal ions of lead, chromium, and nickel, which had high values in the wetland were studied. Three treatments of sawdust, straw and zeolite clinoptilolite (ZC) were used in laboratory columns to investigate the heavy metal removals. The laboratory columns with a length of 1 m and a diameter of 160 mm were prepared and the wastewater were passed through them. The results showed that the maximum adsorption of lead metal ions in straw (37.6%) was better than sawdust (33%) and zeolite (12.2%). Besides, the maximum chromium adsorption in zeolite (44.4%) was higher than sawdust (40.2%) and straw (37.6%). Finally, for nickel adsorption, sawdust (39.4%) gave better results than straw (35.9%) and zeolite (33.3%). However, it seems that all the treatments used are relatively effective in removing the studied heavy metals. However, for maximum Adsorption, it is better to use a mixture of the studied treatments. The results of the one-way analysis of variance showed that the absorption rate of all three heavy metals in the treatments was significant at the 1% level and all three adsorbents had the ability to absorb the investigated heavy metals. Also, according to the LSD test, except for lead absorption by zeolite, there was no significant difference between the adsorbents used.

Pollution entrance into water resources systems, such as urban drinking water distribution networks, can cause irreparable damage to human health as a result of the suction phenomenon.Awareness and understanding of pollutant sources and transport of contamination process in the water network cause suitable modeling of this phenomenon as well as perform a proper crisis management when the contaminants enter the network. In order to simulate the movement of nitrate in the soil, the nitrate advection-dispersion equation was programmed in MATLAB. Zahedan drinking water distribution network has been considered as the study area and potential points with high concentration of pollutants in the network have been identified. Scenario of 24-hour water network simulation, after two hours of contamination, was tested for water contamination by using WATERGEMS, EPANET and EPANET-BAM software., to manage the network pollution crisis, two tools were proposed including detention time and dilution flow. To calculate detention time, the network was divided into four parts including: near, middle, far and very far. The results demonstrated that nitrate concentration near the pipe is unallowable and greater than 50 mg/l and required detention time to treat the quality of water in the nodes of the middle, far and very far decreased 33 to 50, 58 to 62.5 and 75 percent compared to the near nodes, respectively. Moreover, efficiency and positive performance of dilution flow as a tool for quality management was proved. Required dilution flow to treat the quality water was determined from 10.6 to 15.9% of the base pipe flow.

It is necessary to forecast the volume of inflow to reservoir operation in flood conditions, which is of double importance in mountainous basins with a rain-snow regime. The main purpose of the present study was to evaluate the accuracy of GEFSv12 reforecast data as an input to the HEC-HMS precipitation-runoff conceptual model in forecasting and warning issuance for floods entering the Dez dam resrvoir, southwest Iran. For this purpose, after deriving precipitation and temperature parameters (including control values and ensemble members) up to 10-days lead time, the flood ensemble forecast was produced. In the study, in case of exceeding the threshold discharge (1620 and 2640 m3/sec with return period of 2 and 5 years, respectively) by a relative majority of forecasting members, the flood warning was issued. Although, flood forecast in basins with the rain-snow regime is very complicated, the results of evaluation indexes showed that a considerable improvement of forecast accuracy might be expected 5 days ahead (5-days lead time). Then again, there was no direct relationship between the reduction of forecast lead time and the enhancement of forecast accuracy. The results of the probabilistic study of the members’ agreement percent in exceeding the threshold discharge of 2640 m3/sec indicated warning issuance within the forecast lead time of 4-7 days ahead.