نشریه منابع آب و توسعه
سال دوم شماره 3 (پیاپی 6، تابستان 1393)

In recent years, climatic changes have affected many parts of Iran especially central parts and amplifiyed drought occurring and intensity. Bahadoran plain is one of these regions in which frequent droughts have changed the quality and quantity of its water resources. This research aims to analyze the effects of the last decade droughts on groundwater salinity of Bahadoran plain and forecast its effects for a 30-year period in the future. The current condition as well as the climate change in the future (2012 to 2041) were investigated using GCMs (HadCM3 model). Temperature, precipitation and SPI drought index for the next 30 years are used to analyse dry, humid and normal years. Then, water salinity data of the region's wells is used to determine the trends for the current and future periods. The results showed that even if no change occurs in quantity of extracted water from the region's wells in the future is assumed, due to climate change the groundwater quality will change. It will fluctuate between 1 and 2 DS m in different years which can affect many aspects of groundwater consumption in the region e.g. drinking, livestock, agriculture, environment, natural resources, etc.

In this study, application of nano zero valent iron/nickel particles for Cr (VI) removal in porous media was studied. First, stabilized nano Fe/Ni particles were prepared. Then, experiments were conducted in batch and continuous configurations. The continuous experiments were repeated in real groundwater conditions. Based on the batch experiments, corresponding reaction kinetics were in good agreement with the pseudo-second-order adsorption model and reaction rate ranged from 0.001 to 0.03 g/mg/min depending on solution pH and molar ratio of Fe/Cr. Continuous experiments showed that chromate remediation was mostly influenced by seepage velocity, quantity and freshness of nano particles and grain size of porous media. Higher Cr (IV) removal rate in sand rather than glass beads was the result of further surface absorption of nano Fe/Ni particles in sand grain. The maximum Cr (VI) removal rate in batch, lab and bench-scale model were 99%, 70% and 85%, respectively. Finally, in bench-scale model under 15g S-nZVI loading, 118 Lit. treated water with 80% removal efficiency was obtained.

Protection of water resources, particularly groundwater resources is one of the most important issues in modern societies. On the other hand, the management of these resources plays an important role in stable development, and it requires accurate and comprehensive studies resources. In this study, comprehensive climatological, geological and hydrogeological (quantitative and qualitative) investigations were carried out to establish a hydrogeologal framework of Abhar Plain. Based on geophysical investigations, well log data and field survey, Abhar aquifer is an unconfined system and is mainly covered by recent alluvial deposits. The hydrogeological investigations showed that the aquifer is in danger by overdraft and negative water budget. On the contrary, the hydrochemical data are in an acceptable range for drinking and agricultural usages based on the available standards. The final results of this research can be useful for management strategies including aquifer development planning, groundwater modeling and determination of safe yield for water supply.

Nowadays, in order to reduce the effect of unwanted factors and gather information related to land cover, vegetation indices were used. In this study, the effects of NDVI and VI indices on land cover and runoff curve number of Mansourabad watershed were investigated by using Geographic Information System (GIS) and Remote Sensing (RS). Land cover map was prepared by using vegetation indices and Landsat satellite images. In addition, the results of classification of these two indices and corresponding percentage with surveying data were compared. After that, runoff curve number map was prepared by combining land cover map with land use and soil hydrology group maps and by utilizing SCS table in the GIS environment. To assess the accuracy of each curve number map obtained from each index, runoff peak discharges computed by HEC_HMS model were compared by the measured amounts. The result of the classification showed that NDVI index with Kappa coefficient equal to 0.83 was better than the VI index with Kappa coefficient equal to 0.74 for land cover. These results were verified by lower error percentage between the measured and observed maximum discharge for NDVI index.

Due to different reasons like non-normative usage and sequential droughts, water scarcity has highlighted the necessity of water resources management. Studying the processes affecting water resources is necessary for a normative management with sustainable development. The most important hydrologic process is the rainfall-runoff process that influences both ground and surface water resources. The study of this process is closely related to water resources management. In the past two decades, the intelligent models have found more importance because of their high ability in simulation of nonlinear and complex processes like rainfallrunoff process. In this study, the efficiency of common intelligent models in hydrology including Multi-Layer Perceptron artificial neural network (MLP), Radial Basis Function artificial neural network (RBF) and Co-Active Neural Fuzzy Inference System (CANFIS) in rainfall-runoff simulation and estimation of monthly discharge in Balikhluchay watershed was investigated. According to the coefficients of MSE, NMSE, MAE and RMSE (0.0145, 0.276, 0.103 and 0.120 respectively), the MLP artificial neural network which has three hidden layers, three neurons in each layer, a momentum algorithm and hyperbolic tangent transfer which would stimulate the monthly discharge for a 24 month test period with high accuracy was chosen as the most accurate network.

In this research, surface and subsurface drip irrigation system performance was evaluated with considering the moisture front and water distribution on light, medium and heavy homogeneoustextured soils. Experiments were carried out in a plexiglasslysimeter container with transparent walls. Emitters were buried at 15, 30 and 45 cm depths with discharge rates of 2.4, 4 and 6 L/h. Observations of wetting bulb dimensions showed that water moved more laterally than when emitter discharges were high. However, in surface drip irrigation small emitter discharges enhanced water to move downward for the same amount of applied volume but the contrary was observed for subsurface irrigation. Likewise, emitters with high discharge rates also favored water to move upwards toward the soil surface but the contrary was observed when applying the same volume of water.

In this study, to estimate the daily suspended sediment of Kashkan Poldokhtar hydrometric station in Karkhe river basin, the discharge and sediment data between the years 1972 to 2011 were collected. To this end, after generating the missing data, the normality of the data was assessed, and finally estimation by ANN models using multilayer perceptron (MLP) was done. The results of ANN method were compared with those of some models such as linear, median of the data set, monthly and seasonal, hydrological similar period and finally decreasing and increasing periods. The results of ANN method showed a good correlation for evaluating sediment rating curve approaches. Among the methods used for sediment curve, median of the data set was more accurate, for this method gives more weight to the higher flows and has the highest correlation (R2 = 0.98) which is even higher than the artificial neural network method. Moreover, by decreasing the number of points to the least possible, the error caused by conversion of logarithmic functions that depend on the number of distribution points somehow reduces (MSE=0.012).

Several continual droughts in recent decades in our country has caused damage to agriculture and natural resources, particularly, water resources. The basins of Iran are affected by this problem and water scarcity has damaged them. Cloud seeding can be one of the ways to decrease the effect of hydrological drought and increase surface and ground water resources. This paper aims to investigate the effect of cloud seeding on precipitation of Gavkhoni basin and Tashk Bakhtegan basin. Thus, the months of January, February, December and November were selected as the months with the potential of precipitation for evaluation of cloud seeding. Historical regression statistical method was used to for investigate the effect of cloud seeding on precipitation of these basins. In order to detect the target and control areas Arc GIS software was used and statistical analysis was performed using SPSS software. The results of this study indicated that cloud seeding led to a 40% increase in precipitation of Gavkhoni basin and a 23.7% increase in that of tashk-Bakhtegan basin.

The purpose of this study was to investigate the effects of drought on groundwater quality in a period of 10 years (2002 to 2012) using water level data in Piezometric and meteorological drought index (SPI). In this study, using meteorological drought index (SPI), the years 2002-2003 and 2010-2011 years, were considered as dry and wet years, respectively. Based on the results, the amount of different ions was changed in the groundwater, for drought affects input water. These changes follow a specific pattern. In all stations, the amount of minerals in water is higher during dry years compared to wet years. The results showed that water type of all stations is magnesium sulfate and sodium chloride and that the type of water in Bahabad region is not appropriate for drinking and agriculture.

In a broad sense, water productivity (WP) is the net return for a unit of water used. The aim behind improving water productivity is providing more food, income, better livelihoods and ecosystem services with less water. The present study measures the physical and economic water productivity for selected crops in nine cities of Fars province. It was also tried to investigate the comparative advantage of each city with regard to the production of some crops. The results showed that the southern areas of Fars province have low physical and economic water productivity due to bad climate conditions. Thus, increasing productivity is imperative in these areas. The northern and western areas of Fars province have comparative advantage in the production of cereal and grains. Finally, priority of most areas is devoted to the cultivation of vegetables due to the highest yield value and physical water productivity.

Nowadays, the challenge most countries face in the world is excess demand for water. Demand management for eliminating the serious obstacles in increasing the supply of water is one of the solutions. Good Rating of water as a water demand management practice is considered the basis of the programs and policies. This study presents a parametric method to evaluate groundwater. To this end, data was collected through 255 questionnaires. Using a translog production function, the water economic value was calculated and estimated to be 1733 Rials. Thus, receiving the former price (218 RLS) has no economic justification and the price should be gradually increased until the real price is reached.

The present study aimed to compare the effects of macro complete fertilizer on wheat yield in two methods of soil fertilization and fertigation which were carried out in Agriculture and Natural Resources Research Center of Khorasan Razavi province. The project was carried out with 3-branch rain irrigation using 5 sprinklers in the classic steady system. The distance between sprinklers was 6 m and the lateral distance was 6m, as well. Macro complete fertilizer was injected in the middle line by pump.Fertilizer distribution in two pieces adjacent to the tube was uneven and triangular, so that as distance from the middle pipe increased, the amount of fertilizer reduced. By plotting the area in the direction perpendicular to the pipe, the reaction of plants to the doses of fertilizer was evaluated in terms of fertigation. The results showed that as the distance from the injection pipe increases, the concentration of water in cans containing nitrogen, potassium, iron, magnesium, and zinc with reduces. Analysis of variance and comparison of the means showed that fertilizer treatments in fertigation, had the highest yield (4/35 tons per ha). In this sense, soil fertilizer treatment was 3/98 tons per ha, which is 10% lower than fertigation consumption.

Drought is a natural phenomenon with dangerous consequences in all regions of the world. Scientists have proposed several indices for drought evaluation and monitoring which are designed based on the use of meteorological variables and different computational methods. In this research, SPI and SDI indices were used to analyze the temporal characteristics of droughts. The data of daily precipitation and discharge time series of 5 rain gauges and hydrometric stations across Kashkan watershed in Lorestan province from 1969-1970 to 2012- 2013 were used and the value of SPI and SDI for six time intervals (3, 6, 9, 12, 24 and 48 months) were calculated and analyzed. For assessing the effect of droughts on discharge, Pearson correlation method was applied to calculate the correlation between SDI and SPI series for different time intervals, and different time lags were calculated at each station of the Kashkan river basin. The results showed that the correlation between meteorological and hydrological droughts was statistically significant at 99 and 95 percent confidence level. The maximum correlation was found for SPI and SDI of 9 and 12 months time intervals. This indicates that droughts decrease surface flows which strongly affect the discharge values of the same month or the following one or two months.

Droughts have had major effects on chemical quality of groundwaters in Gorgan's plain. In order to determine the trend of groundwater’s chemical and quality changes, due to drought and wet years, 17 wells were selected in different parts of Gorgan plain. The statistical mean of two characteristic months (May as wet and November as dry month) in two typical years (1998 as wet year and 2004 as dry year) were selected and averaged. The results showed that the decrease of rain fall in dry years (such as 2004) caused drastic changes in quality of ground water, so that the Anions and Cations increase.Moreover, TDS, PH and EC in non-superficial (deep to semi deep) aquifers increase. The environmental effects of these changes are manifest as a decrease of well’s Debi in coarse-grain aquifers and settlement in fine-grain aquifers.

Ghaen Plain which is located in southern Khorasan province has arid and semiarid climate. An investigation of the piezometer, depth and hydrographic maps shows the long-term decline in the groundwater level by 0.5 meters per year. An investigation of hydrograph for the last 8 years has shown that the groundwater level had a 5/3-meter decline which is less than the long-term decline in most basins. In order to assess the quality of groundwater, electrical conductivity (EC), chlorine and total dissolved solid (TDS) were analyzed. Then, the trend of changes of these variables was analyzed over time. The increase in these variables with weather changes reduced recharge and uncontrolled exploitation which have caused a decline in groundwater levels and bad quality. Low levels of TDS, EC and Cl from north to south are indicative of the presence of possible layers of gypsum and salt in the north. Their presence in the northeast (Out watershed) is due to water movement from the recharge to the discharge area and mixing of the waters of the southern and the northern parts.

Salinity (EC) is an important factor, especially in the river engineering and water quality studies. In recent decades, the artificial intelligent systems such as artificial neural networks have many applications in various researches, including water resources management. In this study, water electrical conductivity was estimated using artificial neural networks for Simineh-Rood, West Azerbaijan province, Iran. After that, the result were compared with statistical results using conventional methods such as multivariate linear regression. Hydrogen carbonate, chloride sulfate, and the flow rate in the monthly time scale of the period (1992- 2009) were used as the input for linear regression and EC was considered as the output. Criteria of correlation coefficient, root mean square error and coefficient of Nash Sutcliff were used as evaluating criteria for model performance. The results showed that the artificial neural network model has the highest correlation coefficient (0.967), the lowest root mean square error (0.047ds/m) and the Nash Sutcliff criteria (0.706). Overall, the results showed that the artificial neural network model can be used for estimating minimum and maximum rates of water salinity.

One of the drinking water resources has been selected for research based on chemical analysis with nitrate concentration of 53/7 mg/l in northern part of Gorgan city. In this research, natural zeolite has been used for reducing nitrate under laboratory conditions. The results indicated that natural zeolite reduced nitrate at about 13 mg/lit and also reduced hardness by passing 1 lit water through zeolitic bed (at about 1 kg) during a 30-minute time lag. In the chemical analysis, the pH of the water was 7/5 which chaned to 7/3 after passing through zeolitic bed. In this research, the hardness of raw water was 670 mg/l and the hardness was reduced 85 mg/lit in 40 grms zeolite with a time lag of 10 minutes whereas if zeolite weight was 160 grams, during a 30-minute timelag, the hardness would reduce to 175 mg/lit. Therefore, it can be concluded that natural zeolite could be used for reduction of nitrate in contaminated water wells all over the country.

Understanding of bacteria transport within saturated porous media is essential for protecting groundwater from microbial contamination. In this research, the transport of E. coli in homogenous saturated porous media was investigated. The main objective was to evaluate velocity and behavior of E. coli transpor through Loamy sand layer. Comparing E. coli biological tracer with Uranine tracer and also hydraulic dispersion investigation are other purposes of this paper. To achieve these purposes, a physical model withthree sizes of particle were used in these transport experiments. The bacteria suspension were injected in a hole at one side and water were sampled in two holes located at axial distances of 20 and 60 cm from the injection point, two marginal sampling holes at a distance of 40 cm from the injection point and at the output of the model. The results indicated that the advection component has a significant influence on Bacteria movement, but in marginal holes the potency of advection is reduced and causes the repining phenomenon that is observed in marginal holes curves. Bacteria plume indicated a significant difference from conservative tracer. Unlike conservative tracer, bacteria breakthrough curve had three peaks showing front, mean and ripped tile, respectively and bacteria plume has oblong shape.

Jajrood watershed is located in the southern part of central Alborz mountain range which is located in northern Iran. Latyan dam in Jajrood River is one of the main sources of water for Tehran metropolitan area. This study was carried out in an attempt to determine whether or not there has been any significant change in rainfall and discharge over this watershed during the last four decades. Thus, the time series of monthly and annual values of rainfall and discharge for the period of 1967-2008 were analyzed using statistical methods. Trend analysis of Mann-Kendall test was performed and the best-fitted models were determined using the statistical criteria of Mean Error (ME), Mean Square Error (MSE), Root Mean Square Error (RMSE), Mean Absolute Error (MAE) and Mean Absolute Percent Error (MAPE). Probability distributions were fitted and the Kolmogorov-Smirnov tests were used to select the theoretical distribution, which best fitted the data. The analysis of rainfall data shows an increasing trend upstream but a decreasing trend downstream. While river discharge variations show the strong negative slope in recent years in Latyan station, water storage increased by Latyan dam, and water consumed in Tehran result in the decreasing trend of the river discharge.

In this paper, a mathematical model was used to describe the flow through a two layered rockfill dam. The coefficients of equations used were determined by an experimental model and a nonlinear optimization method. The model verification was carried out with the same model. The hydraulic flow in the porous media was not well recognized, because the flow was turbulent in these media. Thus, Darcy law was not valid in them. In this study, three power relationships between Darcy- Weisbach friction factor and Reynolds number were suggested for the three types of single layered porous media (fine, coarse and a mixture of them). By combining these relationships and continuity equation, rating equations were developed both for horizontal and vertical two layered rockfill dams, which had been made from the fine and coarse layers. These equations can be used in reservoir flood routing as rating equations. So, by introducing a hypothesis inflow hydrograph to the reservoir flood routing model, the output hydrograph can be determined, both for two types of two layered and three types of single-layered rockfill dams.