IRANIAN WATER RESEARCH JOURNAL
Year:2014 | Volume:7 | Issue:13|Papers Count:15

Nowadays, mathematical modeling is increasingly used in order to evaluate the spatial and temporal changes of the concentrations of water quality parameters in rivers and reservoirs. In this research, the FASTER model was used for water quality modeling. For simulation of the hydrodynamic conditions of flow, continuity and momentum equations (known as Saint-Venant equations), are numerically solved using the Crank-Nicholson central scheme with a staggered method and varying grid size. The Advection Dispersion Equation (ADE) has been solved using the finite volume technique. According to the available data, the parameters of nitrogen and dissolved oxygen (DO) for a reach of Karkheh River between Paye-Pole and Hamidiyeh stations were analyzed and simulated and Abdel khan hydrometric station was selected as a survey station. For solving the hydrodynamics of flow, it is necessary that Manning roughness coefficient (n) be calibrated in FASTER model. With adjusting of this factor, value of 0.028 was chosen. In this study 4 Dispersion Coefficients (DL), including Fischer et al, Seo and cheong, Kashefipour and Kashefipour and Falconer equations were used. Comparison of the measured nitrogen and dissolved oxygen concentrations and the corresponding model results showed that the Fischer dispersion model and Kashefipour-Falconer dispersion model performed relatively well for nitrogen and dissolved oxygen, respectively. Also according to the concentrations of water quality parameters that have been evaluated in this specified reach of Karkheh River, the concentration.

The behavior of transport and deposition of cohesive sediments due to electromagnetic and physico- chemical properties of the sediment particles study on is too complexed. One of the important parameters involve in the processes of the cohesive sediments transport is threshold of flow shear stress for deposition. In this research a kind of clay- silty sediment obtained from an embankment dam reservoir near Shahrekord was used. All experiments were carried out in rotating flume model and for this purpose, flow velocity and shear stress in the flume was measured using Acoustic Doppler Velocimeter (ADV). The results showed that the threshold of the shear stress for fully starting of cohesive sediment deposition and critical shear stress obtained to be 1.01 N/m2 and 0.038 N/m2, respectively. Finally relationships were derived for calculate the shear stress threshold, equilibrium concentration of sediments and the deposition rate.

Advancement of technology in construction of structure caused to design modern type of bridge piers including inclined bridge piers group. Due to importance of identifying effective mechanisms of scour around this type of bridge piers, in this research the effect of flow parameter and level of bridge foundation on the scour depth was investigated. Bridge piers group included two inclined rectangular piers of 2.5cm width and 3.5cm length which installed at the angle of 28 degree on the top of rectangular foundation of 10cm width and 16cm length. Experiments were performed for various relative velocities, depth of flow and relative top level of the foundation from the channel bed (Z/D*) -1 up to 1. The results showed that the velocity of flow has more effect on the local scour depth in comparison of the flow depth. Comparison of results for different levels of the foundation showed that level of the foundation has significant effect on the scour depth. A maximum and a minimum scour occurred for relative foundation level 1 and -0.5. Furthermore, except of relative foundation -0.5, the scour at the inclined bridge level is more than individual pier.

Many devices and methods are available for the measurement and control of flow rate in open irrigation channels. Among, these devices, sharp crested weirs and sluice gates are commonly used. In order to minimize the disadvantages of weir and gate, they can be combined together in one device yielding a simultaneous flow over the weir and below the gate. In this study the hydraulic characteristics of combined device of weir-gate such as coefficient of discharge and effective parameter on simultaneous discharge were investigated. The relationship between the experimental and theoretical results of the geometric and hydraulic parameters in the function of the flow statistically was analyzed and a coefficient discharge for combinational flow was presented. The error from the application of equation for 95% of data was±2.5 percent.

In this paper, the status of groundwater hydrology and hydrogeology plain of Varzaneh was studied. In the hydrology section, the annual average of Zayandehrood river flow in stations of Varzaneh and Cham was investigated. The unit hydrograph of the plain was also illustrated. In hydrogeology section, the software of RockWorks Ver.15 was used and log of wells and also the geological model of Varzaneh plain were prepared according to the logs and material of their layers. The contours lines of underground water level in unconfined and confined aquifer in the Varzaneh plain were drawn using Surfer Ver.10 software. Also the hydraulic gradient for groundwater flow in the plain area was found. The maximum value of hydraulic gradient was 0.008 from center of plain to the South East. In the past decade, the ten-years unit hydrograph of plain showed that the amount of underground water level was dropped by 1.3 meters, i.e. which the mean of annual loss was 13 centimeters.

The Muskingum model is a hydrologic flood routing method in which the accuracy of its parameter estimation affects the routed hydrograph, especially in the value of the peak flow flood. Meta-heuristic algorithms are good candidates to determine optimal/near-optimal parameters in the Muskingum model. In this paper, shuffled frog leaping algorithm (SFLA) was applied and compared in two benchmark and real case studies. The sum of the squared deviation (SSQ) between observed and routed outflows and the sum of the absolute value of deviation (SAD) between observed and routed outflow as the objective functions (DPO) as an important parameter on the routed flood hydrograph. Results show were considered that the SFLA improves (decreases) the SSQ and SAD by 0.03 and 0.40 percent in the benchmark problem, and by 0.27 and 3.67 percent in the real case study, respectively, compared to reported results using various optimization algorithms. In addition, the SFLA improves (decreases) the DPO of the routed hydrograph in the benchmark and real problem by 17.65 and 3.67 percent compared to the best (minimum) reported result.

Drought is a natural phenomenon that starts slowly and spread equanimity and traces severily on all human activities. Therefore, complete recognition and exact monitoring of drought can provide appropriate tools for dealing with it and decreasing damaging effects. One of the strategic areas that are very important in terms of agriculture is Khuzestan province. This province is very remarkable due to its permanent rivers, flood-prone rivers also various reservoirs. The main objective of this study is to improve drought monitoring by finding dependencies between drought and several oceanic and climatic parameters in different approach in comparison with statistical correlations. In this research used Data Mining Techniques of Association Rules. Drought events were determined according to Standard Precipitation Index (SPI) and its Dependencies were surveyed using oceanic- climatic indices such as Southern Oscillation Index (SOI), Pacific/North American (PNA) Index, Multivariate ENSO Index (MEI), Pacific Decadal Oscillation (PDO) Index and North Atlantic Oscillation (NAO). Results showed that the classes of selected patterns which are dominant on drought are similar in different time delays. It means that drought events are compeer with normal status of indices and are predictable with maximum and minimum accuracy 74.24 and 44.86 percent, respectively. Therefore, these rules can use as a supplement to existing approaches for drought monitoring.

The lip angle of submerged roller bucket as the main design parameter, has an effective role in energy dissipation and scour downstream of this structure. The purpose of this study is the investigation of bucket lip angle influence on the scour process and determining the best lip angle and presentation non-linear regression equations to estimate the scour dimensions downstream of submerged roller bucket. Therefore, 64 tests were conducted in different hydraulic conditions on four experimental models with different lip angles 30o, 35o, 40o, 45o. The results showed that with increasing the lip angle from 30o to 45o, the maximum depth of scour hole, the lengthwise hole expanse, the height of upstream and downstream berms and the relative surge height, increased in average to 150%, 27%, 110%, 24% and 213% respectively. Based on the results of this study, 30o bucket is an appropriate option to reduce the maximum depth of scour, volume of scouring, height of berms and height of ripples in tailwater to the minimum possible and 40o bucket is also a suitable option to further the beginning and the deepest point of scour hole and the surge peak to the maximum extent possible. Both angles have advantages to reduce bed scour, bucket abrasion (Due to the trapped material in unsymmetrical spillway operation) and negative effects of turbulent rippling tailwater on outlets operation and riverbank.

Increasing of water scarcity on the one hand and increasing of water contamination, lead us to find a way for removing the heavy metals (HM) from the resources. In this research, Amberlite (IR-120) were used as sorbents of HM. Experiments were done with one diameter of Amberlite. A randomize experimental design was employed with 15 treatments and three replications. The treatment inclouding five different concentrations of NI, Pb and Cd. The concentration for Pd was: 40, 250, 500, 1000 and 1250 mg L-1 and 4, 6, 15, 20 and 40 mg L-1 for Ni and Cd. The removing efficiency of the Amberlite was measured for Pb and Cd. The results showed that the effect of concentration was statistically significant for Amberlite. It was also observed that the absorption of HM by Amberlite increases linearly. Maximum Pb, Ni and Cd absorption occurred at 1250, 40 and 40 mg L-1 with a value of 62.35, 1.98 and 1.99 mg for 1 grams of Amberlite, respectively. The minimum Pb, Ni and Cd absorption occurred at 40, 4 and 4 mg L-1 with a value of 1.98, 0.19 and 0.19 mg for 1 grams of Amberlite, respectively.

Watershed flood hydrograph derivation is one of the most important hydrologic for hydraulic structures design. One of the most widely used experimental models in this context, is the SCS dimensionless unit hydrograph. Also the Geomorphologic Instantaneous Unit Hydrograph (GIUH) model presented by Rodrigoes-Iturb etal. (1979). Simulates the watershed rainfall runoff process based on quantitive geomorphologic parameters and design rain. In this study the performance of above mention methods wasn investigated over one of the Karoon river sub basin so called Jooneghan basin located in Chaharmahal and Bakhtiari province. Geomorphologic parameters were computed by preparing DEM maps and after simulation, the relative performances of the models were compared. The RME in peak flow calculated by GIUH model, was (11%) while the RME residuat mean squane error in SCS method was (22%). The results also revealed that the GIUH model has performed better than SCS model in estimating flood peakato and time b peak.

For precipitation regionalization of Kurdistan province and access to a suitable pattern in this context, annual precipitation of 83 stations are collected for a period of 30 years (1978-2007) from Applied Meteorological Research Centre of Kurdistan Province. Using rotated PCA approach by Varimax method showed that approximates 86.75 percent of annual precipitation variations of Kurdistan province can be explained by 7 components. The result of PCA used as an entrance of cluster analysis with Ward’s technique and it was distinguished that Kurdistan province has 3 different precipitation regions called west region with high precipitation, central region medium precipitation and east region with low precipitation region. Region East with it, slow precipitation is the biggest precipitation one in the Kurdistan province that Annual mean precipitations is about 368.7 mm. The central region with medium precipitation region is the second large region of precipitation. Annual mean precipitation of this region is about 537.7 mm. Western high precipitation region is the smallest region of precipitation and at the same time it is the wettest region of precipitation in Kurdistan province. The annual mean precipitation of this region is about 706 mm.

One of the major objective of adsorption studies is the determination of required time for optimal adsorption in the solid-liquid. system In addition to research on the effect of sorbent dose, balance time, the efficiency of adsorption and adsorption kinetics models were evaluated. Fitness of measured data with the predicted value by lagergren and Avrami model showed the model not only gives a good estimation of equilibriuim value of absorption but also describes absorption data well. One of the major objective of adsorption studies is the determination of required time for optimal adsorption in the solid-liquid. system In addition to research on t.