Journal of Water Resources Engineering
Year:2016 | Volume:9 | Issue:28|Papers Count:8

In this paper, an Artificial Neural Network (ANN) is designed for the determination of unconfined aquifer parameters: transmissibility, storage coefficient, specific yield, and delay index. The network is trained for the well function of unconfined aquifers by the back propagation technique and adopting the Levenberg-Marquardt (LM) optimization algorithm. By applying the principal component analysis (PCA) on the training data sets the topology of the network is reduced and fixed to [3×6×3] regardless of number of records in the pumping test data. The network generates the optimal match point coordinates for any individual real pumping test data set. The match point coordinates are then incorporated with Boulton analytical solution (1963) and the aquifer parameter values are determined. The generalization ability and performance of the developed network is evaluated with 100/000 sets of synthetic data and its accuracy is compared with that of the type curve matching technique by two sets of real field data. The proposed network is recommended as a simpler and more reliable alternative for the determination of unconfined aquifer parameters compare to the conventional type-curve matching techniques.

The Karkhe River is one of the most important rivers in Iran and is the third largest river in terms of the discharge volume. In its wild state. the river usually left many damage its wake. In order to reduce these detrimental out comes, the Karkhe Dam was built, which is one of the most important and also the largest dams in Iran and the Middle East. This dam has instigated an economic reforminits basin, such as changes in the land-use, amount of water, vegetation and the urban areas. Some of the major changes occurred ofter the dam construction have been evaluated: The Using Landsat satellite images spanning between 1352 and 1392, maximum likelihood classification identifying 7 classes was conducted on the pre-processed images. The results showed the barren soil decrease of 0.2 percent, the residential area, vegetation and water supply have increased by 2.36, 1.4 and 2.5 percent, respectively. In spite of the logical trend of these results, the accuracy assessment was as an added measure to confirmed the previous results. The evaluation showed a high accuracy almost in all of the classification results. The overall accuracy and the Kappa coefficient estimated from the accuracy assessment are higher than 90% and 0.9, respectively, while the user and producer accuracies are more than 80%. This demonstrates the high performance of the maximum likelihood classification.

The hydraulic jump is one of the most important topics In the field of open channel flow, which has been extensively investigated. When a flow condition changes from a supercritical to a subcritical regime, the result is an abrupt rise in the water surface level accompanied by turbulent rollers. This phenomenon is called a hydraulic jump.Many researches have shown that the corrugated beds caused the conjugate depth and length of the hydraulic jump are reduced as compared to those of smooth beds. In this study, a 2D numerical simulation of hydraulic jump on a triangular corrugated bed was simulated using various turbulence models (Standard and RNG k - model and (SST) model) and Fluent software. Also, the free surface was determined, using the VOF method. Hydraulic jump was simulated in a rectangular channel with a triangular corrugated bed, using various Froude numbers within a range of 3-7.5. The numerical results showed that the turbulence model and the VOF method were suitable for predicting the free surface profiles of hydraulic jumps on triangular corrugated beds. The relative error of the predicted free surface profiles and measured value were within a range of 3%-7%. Also, the results confirmed that on everage, the tailwater depth on triangular corrugated beds was 34.8% less than that of smooth beds under similar hydraulic conditions. The numerical model indicated that as the distance from jump’s toe is increased, the turbulent kinematic energy (K) is reduce, Moreover the maximum value of bed shear stress was obtained on jump’s toe.

The Crest of an Ogee spillway with a curved plan is longer than that of one with a straight crest, therefore, its capacity for the overflow at any reservoir level is higher than that of the straight-crested spillway. Thus it is a preferred design in most water ponding projects. The objective of this study was to investigate the degree of its curvature on its hydraulics. This was a achieved on a 1:25 experimental model of the Germ chai ogee spillway at the Hydraulics Laboratory of the Soil Conservation and Water Management Research Institute of the Ministry of Jihadi Agriculture. The results revealed that the cavitation number at any discharge rate was higher than the critical value compared with that of the straight- crested weirs Moreover, the discharge coefficient was lower than that of the other type with an equal crest length.

Under the conditions of limited availability of water resources and the relative abundance of arable land (the conditions prevailing in most parts of Iran), the main objective should be to enhance production per unit of water used and the optimal use of the soil these resources. In this context, a deficit irrigation an alternate furrow irrigation, was investigated at critical stages of maize plant growth, of and their combined effects on dry matter accumulation and water use efficiency was assessed. This research was performed as a randomized complete block design with three replication consisting of six treatments: full furrows irrigation in growing season, alternate furrows irrigation in the entire growing season, full irrigation at the establishment stage and alternate irrigation at other stages, full irrigation at the flowering stage and alternate irrigation at other stages, full irrigation at establishment and flowering stage and alternate irrigation at other stages, full irrigation at flowering and ripening stages and alternate irrigation at the other stages. The highest dry matter accumulation was 257 gr per plant, which belonged to irrigation of all furrows during the entire growing season, and the lowest was 196 gr per plant, which belonged to the alternate irrigation during the the entire growing season. During the most biomas yield (18385 kg) belonged to the full irrigation of all during the entire growing season, bowever, the highest water use efficiency was 1.88’ which belonged to the full irrigation at the flowering stage and alternate irrigation other stages.

One of the important purposes of river engineering science is to protect river banks from erosion phenomenon and to prevent shifting of the main channel path. Spur dike is a hydraulic structure which has a lot of applications for stabilizing river banks and increasing water depth. According to widespread use of this structure, it is important to understand the flow pattern around it. Since flow pattern around a spur dike is complex and fully 3D, 3D simulation was done in this study. FLOW-3D software was employed to simulate the flow around a submerged spur dike. VOF method was used for free surface simulation and RNG k-ε model was used for turbulence modeling. Based on comparison of numerical and experimental results for stream wise velocity component and flow depth, it was concluded that numerical model could simulate the flow parameters with relatively high accuracy. In following, the effect of discharge increase on velocity profiles and flow free surface was investigated. According to obtained results, maximum longitudinal velocity Infront of the spur dike nose and flow depth at the upstream of spur dike increased with discharge increase. In lower discharges, the changes rate was more and vice versa. Also, the ratio of the flow depth at the upstream and the flow depth at the downstream increased with discharge increase.

Recently, low gradient stepped spillways, which can be constructed on the embankment dams, have been getting high attention owing to their easy implementation. A few numerical researches have been conducted to simulate the flow hydraulic on stepped spillways. In this study, the air water flow was simulated using two-phase mixture model. Six models of turbulence including Eddy viscosity, k-ε, RNG k-ε, k-ω, SST k-ω, and ω-RSM were applied to describe the turbulence of flow. According to the results of numerical and experimental tests, it was found that k-w and ω-RSM are superior to describe the turbulence of flow. Moreover, the mixture two-phase model described the experimental data successfully. In addition, the effects of spillway slope, flow discharge, and step height in the amount of energy dissipation were examined. It was concluded that the energy dissipation increases with a rise in the step height and a reduction in the slope and the flow discharge. In the unit discharge of 2.34, the energy dissipation increased from 39 to 50 percent with decreasing the spillway slope from 26.6 to 8.9 degree.

Using wastewater and sewage have some environmental dangers such as water, soil and plant pollution from heavy metals accumulation. This research was conducted to study phytoremediation of vetiver and eucalyptus by absorption of heavy metals from sewage in a contaminated soil with landfill leachate. Plants were irrigated with different types of wastewater in 2012 on the base of a completely randomized design with 4 replications. The factors were 2 type of plants and different quality of wastewater. plant samples were taken and the heavy metals were measured by Atomic Absorption system after 100 days. According to results, few heavy metals had been absorbed by plants from soil and water. Heavy metals accumulation in plants were significant. Concentration of Pb for vetiver roots were more than of eucalyptus roots but the results in shoots were inverse. There was no Ni in plants shoot. The absorption and the concentration of Pb, Ni, Zn, Cu in vetiver roots had a significant difference with eucalyptus. Using different type of wastewater had significant impact on plant growth which caused increasing the absorption of heavy metals by plants and resulted better remediation of soil. The maximum weight of plant drymatter (root & shoot) for eucalyptus was measured 46.47 and vetiver was 59.88 grams per pot for none refined wastewater irrigation. It is recommended to investigate the long term affects of this pollution on soils and plants.