Journal of Hydraulic and Water Engineering
Volume:1 Issue: 2, Winter and Spring 2024

The two-point method is the most commonly used method of calculating the coefficients of the Kostiakov-Lewis infiltration relationship, which is based on the volume balance equation. Using the two-point method of Elliott and Walker (EW), the coefficient of the power relation of water advance can be determined by initially utilizing data from the midpoint and endpoint of the field. Subsequently, the coefficients of the infiltration relationship can be determined. In this study, all the advance data were used to determine the power relation coefficients of water advance. Also, in this research (TR), the point where its infiltration opportunity is equal to the average infiltration opportunity time of the advance phase was considered as the midpoint in the two-point method for determining the infiltration coefficients. The relative error index and Root Mean Square Deviation (dRMS) index were used to assess the accuracy of the advanced relationships and infiltration equations derived from TR and EW methods. The results showed that the advanced relationships obtained from the TR method have higher accuracy than the EW method. The average relative error index of the infiltration depth indicated that the infiltration relations obtained from the TR method with an average relative error of 2.4% is more accurate than the EW method.

Estimation of the volume of suspended sediment load of rivers, especially when dam constructed on it, is one of the tremendous challenges that civil engineers faced. It is crucial to accurately predict the suspended sediment load to effectively mitigate the negative consequences of this phenomenon. To estimate the total suspended sediment accumulated behind the Aland and Ghatoor dams, two models of artificial intelligence, Gene Expression Programming (GEP) and Artificial Neural Network (ANN), were employed in this study. The performance of these two AI models compared with the traditional method, Sediment Rating Curve (SRC), for estimating the suspended sediment volume using hydrometric stations from 1969 to 2017. Unfortunately, the appropriate data from 2017 to the present is not available from authorities of the West Azerbaijan province, so inevitably, we used the hydrologic records till the end of the year 2017 in this article. Two statistical indices were used to evaluate the models: the coefficient of determination (R-squared) and the Mean Absolute Error (MAE). Based on these indices, the intelligent models performed better than the SRC in estimating the suspended sediment volume. In comparing the GEP and ANN models, the performance criteria show that the ANN model produces better results. For the Ghatoor River, the performance indicators of the ANN model were MAE=993.1 ton/day and R^2=0.910, which is 45% and 43% higher than the GEP model and SRC method, respectively. For Aland River, the performance indicators of the ANN model were MAE=519.2 ton/day and R^2=0.961, which is 12% and 57% higher than the GEP model and SRC method, respectively. In conclusion, for predicting the suspended sediment load in Ghatoor and Aland Rivers, the ANN model can be the best choice for this purpose.

Wetting front (WF) and redistribution wetting front (RWF) depend on different parameters such as soil type, soil layering, land slope, and emitter discharge rate. Experiments were conducted on the physical model applying constant 24 litres of irrigation water, three different slopes (0, 10, and 20%), and three different discharge rates (2, 4, and 8 L/h). Three homogeneous soils with light, medium, and heavy textures, and two non-homogeneous soils with horizontal layers (LMH: a light texture in the top layer, a medium texture in the middle layer, and a heavy texture in the bottom layer; HML: a heavy texture in the upper layer, a medium texture in the middle layer, and a light texture in the lower layer) were used. The results showed that when the dripper flow rate doubled, in LMH soil, where the light texture was in the top layer, the amount of wetting depth was, on average, 20% higher than HML soil in which the top layer had a heavy texture. In all experiments, the highest increases in the maximum wetting depths of the RWF in five measurement stages within 24 h after irrigation were related to slopes of 0%, 10%, and 20%, respectively. A comparison between homogeneous and non-homogeneous soils showed that the change in soil layering has a significant effect on the radius and depth of wetting. This matter needs to be considered in the design of drip irrigation systems.

Physical properties of tree species determine their reaction to external loads as a result of water flow. The greater the trees ability to withstand water load, the greater the amount of water energy absorption, generation of water eddies, and the acceleration of turbulence in vegetation canopies. This will increase water flow energy lost. In general, physical properties of trees include leaf density, shape, and overall flexibility of their species. In this study, an index is proposed to characterize physical properties of tree species. This will enable the application of a single momentum (or energy) equation to determine overall reaction of variety of tree species in a community. The index is derived based on the resonance frequency of the first mode of vibration of trees and a fundamental relationship for the homogeneous beams. The derived indexes for four species of coniferous trees were used in a mathematical model to estimate the drag and energy coefficients as representatives for tree reaction to water flow, and could account for the differences due to the leaf density, shape, and rigidity of the tree species.

Breakwaters are structures whose main function is to reduce waves in an area and create a calm basin for the stopping, movement, and maneuvering of floating objects. Concrete armors can be constructed in different shapes, allowing for the creation of armors that have high engagement properties and an increased damage coefficient (KD), ultimately leading to a reduction in the weight of armor pieces and their ability to be deployed in steeper slopes on the breakwater body. Most coastal protection structures built in the country are of the traditional rubble and platform type, and the structures made with concrete armor are few and far between. In this study, the impact of Akmon, Sta-bar, Sta-pod, Stock cube, and Tribar armoring layers on the level of flow rate and wave overwash in coastal protection structures and which type of armor has the least overflow is investigated. First, the overall geometry of the breakwater and then the geometry of each armor layer is separately drawn using AutoCAD software and prepared for calling to the main model, the FLOW-3D 11.0.4 software. After modeling, the results are analyzed through the main model and Excel software. The lowest wave overwash in the breakwater occurs in the Akmon armor state, and the highest wave overwash in the breakwater occurs in the Stock Cube armor layer state. The least flow rate among breakwaters occurred in the Akmon armor state, and the highest flow rate among the five breakwaters also occurred in the Stock Cube armor state, which is approximately.

In recent decades, climate change and drought have led to an increase in groundwater use in the world. In Iran, due to being in the global dry belt and also the impact of climate change, reduced rainfall and surface water, excessive use of groundwater, the amount of this valuable resource has decreased. According to groundwater changes which have led to aquifer storage reduction, aquifers’ evaluation is necessary. In this study, Haraz alluvial fan, located in the north of Iran, was studied using GMS software, MODFLOW and MT3DMS models to simulate groundwater quantity and quality, respectively. . MODFLOW is considered an international standard for simulating and predicting groundwater conditions and groundwater/surface-water interactions. MT3DMS can be used to simulate changes in concentrations of miscible contaminants in groundwater considering advection, dispersion, diffusion and some basic chemical reactions, with various types of boundary conditions. The results of the MODFLOW model showed maximum water level in the southern part of the alluvial fan with 125.07 m and lowest in the northern part, adjacent to the Caspian Sea coast with -17.52 m. Also on MT3DMS model output which was prepared based on Cl concentration, maximum amount of this agent is 297.17 mg/lit in the East and the North-West of the study area. Management policy applied was utilization of the alluvial fan aquifer within 2020 as much as previous year. Model predictions indicated that water level in piezometers increased 0.75 m during 2021 and the maximum amount of Cl concentration remain unchanged. According to the results,

Knowing more about the flow behavior of short-stepped shaft spillways helps to use this structure better and more efficiently. Moreover, using a vortex breaker greatly affects passing flow through Shaft Spillway. For use more efficiently, the risk of the flow of water on the crest decreases to less than fluid vapor. The water head on the crest, called cavitation, should be prevented as long as possible. This research has tried to experimentally study different behaviors of stepped chambers and different vortex breaker shapes on spillway flow. From the viewpoint of the effects of flow regime changes on spillways, changes according to the vortex breaker shapes, and the change of type of flow range will be studied effectively. Finally, the best relationship between the water head on the crest and the discharge coefficient was determined. One of the most important issues on the hydraulic coefficient of the spillway is related to the relationship between the water head on the crest and the hydraulic coefficient of this special hydraulic structure. In other words, when flow changes and moves upward till full pipe condition, knowing about the empirical coefficient of the spillway is very useful to predict hydraulic behavior in different situations.

Weir is one of the most common man-made hydraulic structures that are used to measure the flow in canals, store water, and control floods. The piano key weir (PKW) is a type of non-linear weir and is considered one of the best hydraulic-economical options for use in improvement projects to increase the discharge capacity during floods and increase the reservoir volume (with increasing the length of the water passage in a fixed width of the construction) in new dam construction projects. The purpose of this research is to numerically model the flow and investigate the effect of simultaneous changes in the number of cycles and the weir angle on the discharge coefficient by trying to keep the total length of weir crest and other geometric parameters constant for all models. After the investigations, it was found that increasing the weir angle of the PKWs in a fixed length, for all models, increases the flow coefficient while increasing the number of cycles in a fixed length, for all models, leads to the reason for the reduction of the area of the inlet keys, increased contraction of streamlines and the subsequent intensification of the local submergence in the outlet keys, the discharge coefficient will decrease significantly. In the end to predict the changes of the discharge coefficient variable, the conditions of using the multiple regression model, two groups of dimensionless parameters depending on the geometry and flow through the weir were examined and new relationships were presented to calculate the discharge coefficient.

Nowadays, streamlined weirs including circular crested weirs and hydrofoil weirs have been introduced as the weirs with high discharge coefficient (Cd). In this study, the Cd e of circular crested weirs including cylindrical, semicircular and quarter-circular weirs were compared with the hydrofoil weirs. This was done using data published in reputable journals. The trend of the published data showed that the o Cd f of the semicircular and cylindrical crested weirs are close to each other and vary between 1.00 and 1.40. The Cd e of the quarter-crested weirs varies between 1.00 and 1.25 and the Cd of the hydrofoil weirs varies between 0.95 and 1.05. It should be noted that for all models, the range of the ratio of crest height to weir height varied between 0.5 and 2.10. The results showed that the Cd of the semicircular weir was about 30% higher than that of the hydrofoil weir. The Cd of semicircular weirs is about 10 percent higher than that of quarter-circular crested weirs.

Mared Dam in northern Abadan is under construction on the Karun River and it is the first ship lock in Iran. In this study, the ship's lock was examined. Every vessel must pass through this lock in order to transport water from Arvand River to Karun and vice versa. The interior dimensions of the Mared Shipping Lock are 160 meters long, 25 meters wide and 8 meters deep. Several important times are calculated for lock operation. 𝑇is the first time the gates open, 𝑇15 the time the initial gates remain open until the height difference between the two sides reaches 150 mm, 𝑇filled is the duration between the start of the opening the gates till the difference between the two ends becomes zero after 𝑇15. Finally, T is the total time required for opening or closing the gates completely. The rotational speeds of the gates range from 5 to 35 radians per minute. Numerical modeling has been used to study fluid behavior and interaction between fluid and gates in flow 3D software. Different lock maintenance scenarios have been analyzed. Important parameters such as inlet and outlet flow rate changes from gates, water depth changes at different times, stress and strain fields, hydrodynamic forces acting on different points of the lock have been calculated. Based on this, the forces acting on hydraulic jacks and gates have been calculated. The minimum time required for the safe passage of the ship through the lock is calculated.

Nowadays, one of the most fundamental challenges for human society and the natural environment is climate change. Human activities play an important role in increasing the temperature in different temporal-spatial scales. In this research, the sixth report scenarios of climate change by IPCC were used to evaluate the effects of climate change on the Temperature and Precipitation in Damghan, Iran. Climate change occurrence was predicted by using the HadGEM3 and CanESM5 models under the SSP126, SSP245, and SSP585 scenarios. The rainfall data from the Damghan synoptic meteorological station and Damghan rain gauge station have been used for calibration and validation for the 2000-2020 period. Then, a prediction was made for the 2020-2040 period. To predict the future temperatures (2020- 2040), minimum and maximum temperature data from the Damghan synoptic station was used. LARS-WG6 software was applied for the statistical downscaling of climatic data. Then, by using the predicted temperatures and rainfall under the climate change scenarios, the outflow intensity and pollution load of the reservoir water for 2020-2040 was presented. Considering the increase in the pollution load in some seasons and months and the downstream use of water, the construction of a water treatment plant and prevention of pollutants from entering the urban drinking water network is suggested. If management methods are planned and applied, the water quality of the dam reservoir can be improved.

This study evaluates the scenario of the flood backwater impacts on upstream of the Sunkoshi-Marin headworks. The design flood and hydrological analysis were carried out based on the stream flow data from 1968 to 2015 of Khurkot station. Probabilistic method was used to estimate design flood discharge and check flood values for 1000 and 10,000 years return periods frequency. Estimated design floods and check floods were 12,328 and 15,630 m3/s discharge respectively. Numerical simulation of backwater effects was carried out in three different cases- (i) headworks without affecting existing road (ii) headworks affecting existing road and (iii) headworks with inline structures using HEC-RAS. Water surface profiles estimation and backwater innundation map was generated for 1000 years return period flood. In the case (i) scenario simulated upstream and downstream water surface were 478.10 m and 477.22 m respectively. In the case (ii) those values were found 471.75m and 470.64 m respectively. Like wise, in the case (iii) scenario upstream and downstream water surface were found 475.79 m and 471.39 m respectively. The total inundated area including the river waterway was 340.89 ha with the extension up to 6 km in the Tamakoshi side and 8 km in the Sunkoshi side. The net inundation area excluding the river waterway was estimated 216.92 ha. The inundated areas lie within three rural municipalities, namely; Sunkoshi, Khadadevi and Manthali. Due to backwater innundation recommended length of the realigned section of the BP highway is about 1.3 kms.