فصلنامه مهندسی منابع آب
پیاپی 41 (تابستان 1398)

Water resource management in arid and regions has high importance. Since in these regions most of demands are programmed based on groundwater so inform of quantity and quality situation of groundwater is very necessary. General Circulation Models (GCMs) outputs are useful instrument for forecast of variations of hydrological parameters. In this study to assessment of global warming impacts variations of rainfall patterns which has been influenced by climate change effects were first evaluated by using of best GCMs outputs and in continue balance conceptual model was examined to analysis of quantity situation of Birjand Aquifer. Calibration and validation of balance conceptual model was performed by using of Multi-objective Particle Swarm Optimization and observation water table (from 1390 to 1393). Fitness functions in this optimization were RMSE and R2. Results of optimization showed that ranges of fitness function in calibration period reached from 0.96 to 0.2 and from 0.77 to 0.97 for RMSE and R2 respectively. Also value of these indices reached 0.84 and 0.91 for RMSE and R2 respectively in validation period. In after step estimation of aquifer water table performed by input of rainfall predicted into balance conceptual model. Relying of conceptual simulations it is expected that cumulative head loss and groundwater table will reach to 7 and 1315.9 m in end of future period respectively.

One of the consequences of global warming and climate change is shifts in tempospatial of important atmospheric parameter precipiation. The aim of this study is detection changes in precipitation waiting time duration in Kurdistan province during recent decades. To doing this research daily precipitation data from 162 synoptic, climatic and rain gauge stations in and out of province during 1/1/1340 to 11/10/1391 extracted from Kurdistan Regional Water Company and meteorology organizations. By geostatistic Kriging method daily precipitation interpolated on 6 6 kilometer and one digital map has been created for each days. Then data over province on the 811 pixels that covers whole of province extracted. One data base in 18914*811 dimensions has been created that locate days on the rows and on the columns pixels. The average waiting time duration calculated for each pixels during different months. The Mann Kendal nonparametric statistics test fitted on the average waiting time duration time series at 90% confidence level. The chages rate estimated by linear least square method. The results showed that waiting time duration has been longer in cold seasons while shorter in warm seasons. The decrease rate of waiting time duration is twice waiting time duration increse. The distribution of significant trend over Kuridstan province show that waiting time duration is longer in semiwestern parts. In contrast in semieastern parts precipitation waiting time duration is shorter.

Drought is one of the most common natural events that has a great negative impact on agriculture and water resources. Using the indices is necessary in order to monitor, evaluate and statistically analyze drought in each area. Recently, a powerful drought index, the Reconnaissance Drought Index (RDI), is gaining wide acceptance mainly in the arid and semiarid climatic regions. Since RDI is based both on precipitation and potential evapotranspiration (PET), it is interesting to assess the effect of the PET calculation methods on the drought severity characterization obtained by the RDI. This paper compares the results of the RDI for various reference periods using some popular empirical PET methods with minimum data requirements. The selected methods are: Hargreaves-Samani, Thornthwaite, Blaney-Criddle, Jensen-Haise and FAO Penman-Monteith. The FAO Penman-Monteith method is used as reference method. The data used are from meteorological stations in thr Tehran Province representing different climatic conditions. No significant influence on RDI was detected by using the selected PET methods. However, the Blaney-Criddle method performed relatively better. This supports the conclusion that the RDI is a robust drought index not dependent upon the PET calculation methods.

Application of remote sensing and geographic information system to the preparation of thematic maps and their integration in the form of zoning maps provide an important tool for assessing the potential of groundwater recharge sites. Thematic maps using effective factors in recharge activities namely the hydrogeological factors such as spring discharge and structural factors such as joint and fractures; lithological factors such as formation type; topography such as slope, slope aspect and topographic wetness index; and climatological factors such as rainfall, temperature, and also land use were applied in preparation of the groundwater recharge potential map. Thematic maps were prepared using remote sensing and by a referring approach and pair-wise and applying an expert view and also by field observations. Every thematic map was weighted and rated with respect to its effect on recharge. Finally, differently weighted maps were rated to prepare groundwater recharge site map. To verify the relative accuracy of groundwater recharge potential map, discharge of springs in the study area was used. The results show that most of the catchment area of the large springs located in the areas of high recharge potential, indicating the relatively high accuracy of the above-mentioned method.

Determining the longitudinal dispersion coefficient (LDC) for Advection-Diffusion equation is the first step in water quality modeling for one-dimensional water bodies such as rivers. In this research, an artificial neural network (ANN) model has been developed based on the standard numerical optimization algorithms and heuristic techniques to determine the LDC. In this regard, conjugate gradient (CG) training functions including Fletcher-Reeves, Polak-Ribiére, Powell-Beale and scaled conjugate gradient functions from the standard numerical optimization algorithms category and resilient back-propagation (Trainrp) training function from the heuristic algorithms, have been applied to optimizing ANN parameters. Then, the best model has been selected for each of the training functions according to indices that are used to evaluate results. Among the selected models, the ANN model with the Trainrp training function has been selected as the best model to predict the LDC due to DDR statistic. Finally, a comparison has been undertaken between the selected model and other suggested artificial intelligent methods by the researchers. According to the implemented comparisons, the Trainrp function acquired the best performance.

Beacause of the hydraulic jump unstable behavior in adverse-slope stilling basins downstream of sloping beds, the jump toe is transmitted on sloping bed. Therefore, formation of the B-F jump is common in practice. In this research, using dimensional analysis and Incomplete Self-Similarity (ISS) theorem, a general equation was derived to computation of the sequent depth ratio of a B-F jump on smooth sloping bed. The experiments were conducted in a physical model for three different slopes of upstream channel (13.5, 21.5 and 29.5 degree) and downstream stilling basin (-0.05, -0.1 and -0.15 %). The results showed that the sequent depth ratio decreases as the slope of stilling basin increases so that for the stilling basin with the slope of 0.15 % and for the constant position of the jump (E0=0.5), the sequent depth ratio decreases about 60% compared with the slope of 0.05% . Then, the roller length was investigated and based on relative energy loss in the jump a general equation was derived to calculate the roller length of a B-F jump. The results showed that the equation of roller length is independent of upstream channel and stilling basin slopes. Finally, using all of the experimental data the required coefficients were calculated and the mean percentage errors were obtained 8.71 and 13.31 % for the sequent depth and roller lenghth equations respectively

One of the scour-control methods around the bridge's pier is use a slot. In the present study the effect of the shape of slot, on local scour around bridge piers have been studied. In order to achieve the study objectives, two sizes, diamond and square with an equal surface area slot, on three levels near the water surface, bed level and under bed level at four Froude number (0.19, 0.24, 0.27, 0.3) tested and then the bed grading were changed and four shape of slot at two level near the water level and on bed level at Froude number 0.24 are tested. The result show that the maximum scouring and The volume of the scour hole with slot level relative to bed Froude number has direct relationship and with area of slot and The average grain size bed has inverse relationship. With compare of data, increasing in second moment of area, depth of scour, volume and dimension of scour hole is increased.

Groundwater is the sole source of water for many of arid and semi-arid regions in the world. Groundwater overexploitation, drought and climate change have deteriorated the groundwater quantity and quality in recent decades. The decrease of well discharges is one of the main results of the falling the groundwater level. Increasing the depth of abstraction wells has been proposed to remedy this problem. This study aims to determine the optimal depth of wells in Kashan plain such that the remaining groundwatercan supply the water demands in a 15 years period. For this purpose, geological information along with data such as groundwater level in observation wells, aquifer bedrock, aquifer hydrodynamic coefficients and groundwater chemical quality data were used. Also, the prediction of the future status of groundwater quantity and quality were carried out on the basis of this data. Changes in the groundwater quality and quantity also were studied with considering the various scenarios of groundwater levels decline compared to its normal trends. According to the achieved results, The scenario of a decline of 25 percent compared to the normal trend were considered as the most appropriate management strategy to determine the optimal depth of water wells in the Kashan plain. Since the depth of the many of the existing wells is more than the proposed amount in this study, the increasing the depth of abstraction wells is not recommended in the study area.

Kohrange sub-catchment is one of the main sources of North Karoun River. Climate variables, such as precipitation and temperature might have considerable impact on discharge of North Karoun River. To evaluate the impact of these variables, 27 years climate data were used. For this purpose, the mean of last ten years of 8 variables including, annual mean, max and min temperatures, number of snowy and rainy days, amount of annual rainfall, max daily rainfall intensity at Kohrang station and discharge of Dezak hydrometric station over mean previous years were evaluated and analyzed using Mann-Candall and Sen’s estimator methods. The above statistical methods showed that the mean annual temperature has increased by 1.5 degrees Celsius compared to mean of previous years at the level of 95 percent confidence interval, but the max and min annual temperatures did not show a statistically significant trend. Although, the max daily rainfall intensity and the number of snowy and rainy days have reduced annually, but these tests did not show a statistically significant trend either. The above mentioned statistical tests confirmed decreasing trends in annual precipitation by 11 percent (155.4 mm/year) and 19.7 percent in discharge at Dezak hydrometric station.

. to evaluate the synoptic and dynamic conditions of atmospheric circulation patterns to identify resources of moisture that transfer from surrounding areas to the study area.For this purpose at first, the southeast of the Iran were selected as the study area. Then the data required consists of two group environmental data and atmospheric data from the database to the desired timeframe for 13 years (1974-2000) was extracted. The data required consists of two group environmental data and atmospheric data from the database to the desired timeframe for 13 years was extracted.These data includes sea level pressure maps, geopotential height at 850 and 500hpa, Omega, moisture flux , specific humidity and a composite map of sea level pressure and humidity, were used for synoptic analysis.The results showed that on most days of precipitation in lands occurred earlier from the sea. The results also suggestion that the occurrence of heavy precipitations, mostly due to the difference in pressure between the Pakistan's low pressure and Tibetian high-pressure systems. In addition, at the periods that the Pakistan low pressure intensity and broadened considerably, track the transfer of moisture through the Arabian sea and the Gulf of Oman warm waters to the Indian subcontinent, and since moving to the west and then effected the South-East of Iran.when the area and intensity of Pakistan low pressure decreased and the Azore high-pressure system were spread from west to east of the Middle east , moisture from the Gulf of Oman to Iran's internal regions has changed.

This research was conducted on Chardoly groundwater aquifer located between Kurdistan and Hamadan provinces in the west part of Iran. For this purpose, the aquifer groundwater data qualities were used from year 1381 to 1387. During all years of investigation, different water quality parameters were analysied and compared to different drinking water, agriculture, corrosion and sedimentation standards. The analysis were completed based on 25 wells groundwater data qualities. In this study the selected groundwater quality parameters for comparison were as pH, HCO3-, SO42-, Cl-, Mg2+, TH, Ca2+, K+, Na+ TDS, Co32- and EC. Finally, the results of quality analysis was entered in GIS software under descriptive layers and Co-Kriging interpolation method based on the minimum interpolation error, and detected to produce quality maps. The results of groundwater quality investigation showed a decrease on groundwater quality from year 1383 to 1385 and an improve and recovery quality from year 1387. These changes were in agreement with a drop in groundwater levels in 1384 because of low rainfall and extra groundwater use, because of extra wells drilling in the resigon. Moreover, the results showed a lower groundwater quality for northern and near the exit part of Chardoley plain aquifer.

The purpose of this study was a quick and easy separation  of Ni(II) from an aqueous solution by a hand-held magnet to prevent secondary pollution. Morphology and other structures of NPG@Fe3O4 were characterized by the  SEM and XRD techniques. The amount of optimal adsorption factors determined by carrying out 96 tests. The effect of various parameters on the absorption processes such as pH, contact time, adsorbent dosage, temperature and initial concentration in the reduction of contaminant concentrations were considered. The results showed that the optimum pH was 6.0, the optimal contact time was 30 minutes and the optimum adsorbent dosage was 50 mg/L. Adsorption isotherm models studied by both the Langmuir and the Freundlich isotherms was also followed by both the pseudo-first and second order models. The results also indicated that the showed adsorption process best fitted to Freundlich isotherm and pseudo-second order kinetic models. The Thermodynamic studies reviled that the adsorption process was endothermic and spontaneous. The maximum absorption capacity 82.25 mg/g indicated the optimal absorption of nickel from water by the synthesized nano adsorbent from graphene oxide.