نشریه پژوهش های حفاظت آب و خاک
سال بیست و یکم شماره 1 (فروردین و اردیبهشت 1393)

One of the factors that are required in the regional analysis is obtaining hydraulic homogenous regions and assessing the appropriate statistical distribution function in each homogeneous region. In this study, the methods of linear moments and Cluster analysis in SPSS were used for making homogeneous groups. And to select the good distribution, HAYFA was used to determine the best regional distribution by low flow. 29 hydrometric stations with appropriate long duration and uniform distribution in Golestan province were selected. The minimum duration of daily flow records was 11 years for Nomel station and the maximum duration of 44 years was for Galish station. After sorting the daily flow the number of courses was characterized with low flow and also the maximum days number with low flow was determined. The method of linear moment and cluster analysis in SPSS, was used to assess homogeneous regions. The study area is divided to 4 regional homogeneous categories based on maximum days with low flow. Using both homogeneous Hosking and Wallis statistic method, there is no awkward station and region is quite homogeneous. Finally, using the index z and executive file in FORTRAN, the best regional distribution function for different extracted homogeneous groups was determined. Based on maximum days with low flow, distribution function of Pearson type 3 for regional 1, 3 and normal for regional 2, pareto for regional 4 were the best methods.

The goal of this paper is to optimize the cultivation area and evaluation of performance of Bilesavar irrigation network under climate change. In this regard, precipitation and temperature data was downscaled using IDW method under A2 and B2 scenarios, using Hadcm3 model for 2010-2039 and 2050-80 future and base (1970-2000) periods. Then the potential evapotranspiration and new irrigation demand were computed for cropping pattern and the performance of the network was evaluated in condition of limited water resources. Results of the research showed that A2 scenario in comparison with B2 has a critical condition. Therefore, in the worst case, temperature increases by 18% and rainfall decreases by 57% in comparison with base period. Also, the volume of water demand shows an increasing trend between 8-10% in the 2010-2039 period and 13% in the 2050-2080 period compared to base period. Moreover, changing optimal cultivation was investigated as a strategy to adapting to the climate change phenomenon using Lingo model. For instance, the optimization in future periods reduced 200 and 430 ha of cultivation area compared to the base period, respectively. Evaluation of network performance showed that the equity and adequacy indicators decreased and energy consumption (KWH) increased compared to the base period.

Regional flood frequency analysis is carried out by integrating L-moments and fuzzy cluster analysis in north east Iran. L-moments based homogeneity test revealed that entire region is absolutely heterogeneous. Removing discordant sites, homogeneity was not achieved for the study region, therefore Fuzzy C-Means algorithm is applied to gain acceptable homogeneous regions. Cluster analysis based on site characteristics and at-site statistics resulted in heterogeneous regions. It is because of not existing a significant relationship between site characteristics and probability weighted moments. Screening L-moments pattern by fuzzy cluster validation indexes, XB, S, SC, PC, DI and ADI and homogeneity measure H, the optimum number of regions ascertained to be c=3. By applying fuzzy C-Means algorithm, the whole study region is divided into three north, middle and south sub-regions. Based on the goodness-of-fit test, ZDist, GPAR distribution is determined as the best fitted regional distribution for the north and middle and GLOG distribution is determined for the south homogeneous sub-regions. Regional growth curves (RGC) are then constructed by the applied regional distributions. Because of increasing coefficient of variation (CV) of the peak flows, the regional growth curves tend to increase from north to the south.

One of the most important factors for applying of pressurized irrigation systems is water quality. So, it is essential to study feasibility of pressurized irrigation systems based on water quality, prior to their performance. It also helps to prevent energy, investment and resources losses. In the present study, the possibility of performance of pressurized irrigation system (sprinkler and drip irrigation system) using geographic information systems (GIS) and its analytical functions was investigated based on groundwater quality in the plains of Hamedan province. The maps and obtained results showed that there were maximum limitations with regard to water quality in the northern and central plains of study (Kaboudarahang, Razan-Qhahavand and Hamedan-Bahar plain). For sprinkler irrigation systems, the most serious limitation was observed in 86.54% of Kaboudarahang plain area. Razan-Qhahavand and Hamadan-Bahar plains, with 70.52% and 33.83%, respectively, were placed in the next rank orders. Also, for drip irrigation system, Razan-Qhahavand is the plain with poor water quality with 38.52% serious limitation. Furthermore, it is Tuyserkan and Nahavand plains which have the most suitable conditions to use pressurized irrigation systems regarding groundwater quality.

Effects of drought is not limited only to arid and semiarid regions and can have a harmful effect on groundwater resources. Occurrence of severe drought is resulted in reduction of surface water resources in the country and use of groundwater increased. In addition to this severe drop in water levels in groundwater aquifers, changing in groundwater quality and increasing use of these resources for consuming a drinking water are other problems. Nitrate is a common contaminant of drinking groundwater. In this study, temporal variation of the concentration of nitrate in drinking water wells were reviewed in the region in the period of 1383 to 1389. In addition, based on the monthly rainfall amounts, standardized precipitation index (SPI) has been analyzed by software DIP to determine seasonally and drought effects on groundwater nitrate concentrations. Also the water table changes were drawn and the effect of changes in water table was determined based on the fluctuations of nitrate concentrations. The results showed that the drought and water table changes did not have clear relationship with the nitrate concentration in this region. Therefore, domestic sewage could be a major source of groundwater nitrate in the study area.

The issue of crisis management in countries and communities is one of the most important challenges in the past and present time for human beings. So far, in countries and communities, there have been many attempts to increase the managerial power especially in the encountering stage, but these attempts have had many advantages and weak points. This research deals with inspecting and studying the existing theories and models and the specific conditions of Golestan province, esp. the natural disasters for flooding and firing, which have been the most frequent problems in this province in the encountering stage particularly in managerial dimensions including conditions of decision making, principles of coordinating and gathering sources and facilities and communications and alarming systems. It also seeks for a definition for the function and conditions of the role of these managerial dimensions to help the managers of this province in encountering natural crises. The objectives and Methods discussed in the present study are applicable and analytical. On the other hand, it should be pointed out that the research pattern and criterion extracted from theoretical bases, have been investigated and approved by using a survey program involving 15 experts. The statistical society of the research involves 300 individuals from managers and experts and Golestan management Coordinating Council and Subsidiaries cities, which on that base the number of calculated statistics is 81. To analyze the data collected, SPSS software and multivariate regression analysis and Friedman test was used. The investigation to calculate face validity of the components dimensions and the relationship between them and also the amount of validity of each component variables, besides, the mutual effects and prioritization of the aspects and components, were calculated quantitatively using SPSS software and multivariate regression analysis and Friedman test. Finally, Golestan natural disaster management model involving aspects of decision making and the alpha coefficient 0.326 (The components of threat, time pressure, surprise) principles of coordination and the alpha coefficient 0.305 (the component of unity of command, Command Line, gamut monitor) mobilize resources and the alpha coefficient 0.292 (Component of the resource, type of resource, resource capacity, quick access resources) and warning systems and information and the alpha coefficient 0.288 (The components of the collection of information, public information and awareness within the organization) were approved.

This study was conducted to know the intensity and spatial pattern of soil heavy metals pollution around the national Iranian lead and zinc complex factories in Dizajabad area, Zanjan province. A sum of 272 surface samples (0-10 cm) were collected based on a grid methods with nodes of 250 and 500 meters and the samples were extracted with HNO3 and the concentrations of Pb, Zn and Cd were determined. Average concentrations of Pb, Zn, and Cd in soil were 181.3, 182.28 and 1.48 mgkg-1, respectively. To study spatial pattern of variables, experimental variograms were calculated and best model was fitted in each case, which was exponential for all. Influence ranges for variograms of Pb, Zn, and Cd were 1131, 1073 and 1026 m, respectively. Using ordinary kriging method, interpolation was carried out, which performed well. To classify the data in taxonomic space, a fuzzy c-means with extragrades clustering algorithm was run on the data using several fuzziness exponents (Φ). Plausible fuzzy clusters were obtained at Φ=1.2. To find 7 as the optimal number of classes from a 2-10 assemblage, fuzziness validation functions F, H and S were used. Most polluted classes A, B, E and G are located at center and around the factory, while C, D and F are covered northern, northeast and southeast parts of the study area. Major parts of extragrade class was the location of factory and landfill compliance.

Topography is one of the major factors controlling the spatial pattern of saturated areas, which in turn is a key to understand much of the variability in soils and hydrological processes. The topographic wetness index (TWI) which combines local upslope contributing area and slope, is commonly used to quantify topographic control on hydrological processes. On the other hand, the interaction of topography with the climate affects the distribution of soil organic matter (SOM) as one of the most effective soil quality parameters that has been shown to correlate with TWI and can be predicted by TWI. The main objective of this study was to evaluate different flow direction algorithms of TWI and to select suitable algorithm for the study area and to map soil organic carbon in a loess hillslope of Toshan area, Golestan Province, Iran. TWI was calculated by single flow direction (SFD), biflow direction (BFD) and multiple flow direction algorithms (MFD). 135 Samples were collected at random systematic method (0-20 cm depth). The results showed D-Infinity (BFD) and MFD algorithms in the study area had stronger correlation with SOM than SFD (D8 and RHO8) algorithms. However TWIs used in most studies are calculated using a SFD algorithm, which assumes that all water from a grid cell flows into only one neighboring cell. But this assumption is not always valid, especially in areas with low relief where movement of water may be divergent. Finally, TWI is suggested to be calculated with different algorithms so that the best method could be selected to obtain accurate results.

Groundwater is a prominent source of drinking and domestic water in the world. In this context a reliable water supply policy, specifically during the dry season necessitates accurately acceptable predictions of water table depth fluctuations. The inter-comparison of three artificial intelligence (AI) techniques are presented using the results of water table depth fluctuation time series. These models comprise Artificial Neural Network (ANN), Adaptive Nero-Fuzzy Inference System (ANFIS) and GeneExpression Programming (GEP), which are for water table predicting of Zarringol basin in Golestan province, Iran. The monthly mean water table data with a period between 1980 and 2010 were used for training and testing the models. Statistical parameters, namely, the root mean square error (RMSE) and determination coefficient (R2) were used to measure their performance. Overall, the results indicate that ANN, ANFIS and GEP models could be employed successfully in forecasting water table fluctuation. The best performing model, The highest coefficient of determination for Salakhgheib well (R2=0.83), Kochak Khortom well (R2=0.80) and Imeretaremola well (R2=0.84) calculated that these values are related to gene expression programming method. However, the performance of GEP displayed a better edge over the other two modeling approaches in most of the respects especially in giving explicit expression for the problem.

Awareness of the impact of water deficit stress on kiwifruit quantity and quality is essential for irrigation management and production. To evaluate the performance of kiwifruit under water deficit stress, this study was conducted in Sari Fajr Company in a completely randomized design with three treatments and three replications in 2011. Treatments included full irrigation (FI), partial root zone drying (irrigation alternating between two sides of the root) (PRD) and regulated deficit irrigation (RDI) at 75% level. The root zone moisture was measured by TDR moisture sensors. The amount of irrigation water was determined from difference between soil moisture within the root zone and moisture at field capacity point. Evaluating the fruit performance was conducted by measuring the fruits quantitative and qualitative traits including fruit volume, size in different directions, fresh and dry weight, moisture, titratable acidity (TA) and total soluble solids (TSS). Depth of irrigation water for FI applied during plant growth and deficit irrigation treatments were 235.60 and 137.60 mm respectively. The amount of water-saving of deficit irrigation treatments compared to FI during vegetative and applying deficit irrigation treatments were 14.60% and 25% respectively. Comparison between treatments according to Duncan's test showed that effect of treatments on fresh and dry weight, volume, y and z dimensions was significant, but not significant for characters x, TSS, moisture and TA. The highest amounts of TSS were at RDI. The results showed that applying deficit irrigation treatments caused to improve the quality of fruit and saving water at water deficit condition.

Experimental and field studies show that the local scour around bridge piers is a main cause of bridge failure. In fact flow pattern affects on erosion and sedimentation around bridge piers. Therefore, determination of depth, occurrence and development of scour hole are important in the hydraulic design of bridges. Due to the geotechnical and economical reason, group piers are used in bridge design. The present study focuses on scouring around side-by-side piers with various spaces between them, then the effect of raft footing on mechanism and amount of scour has been investigated. The results showed the scour depth decreases as the spacing between the piers increases and for G/D=6 become near the single pier. Also by using raft footing, the scour depth in front of pier decreased about 55% and two scour holes created downstream of the footing which moves the location of maximum downstream scour depth far away from pier.

Identification of dust sources and its potential to disperse is important, particularly in assessing atmospheric pollution by dust. The atmosphere of Isfahan Province is heavily affected by dust. To study the properties of deposited dust in the Isfahan area, 36 locations distributed over the cities of Isfahan (an urban area with heavy traffic), Khomeinishahr and Falavarjan (an urban area with low traffic) and Zarinshahr and Mobarakeh (an urban and industrial area) were randomly chosen. Dust samples were taken from all the locations for a period of 5 months in 4 periods from August to Mid December 2010. Geochemical and mineralogical characteristics of all the dust samples were examined. The mean EC value of the dust samples was 5.6 dS m-1 showing that it was highly affected by the Na concentration. This variable decreased from Isfahan to Zarinshahr. Dust particles had an average silt, sand and clay content of 52%, 17% and 31%, respectively. In all the 3 areas, kaolinite, palygorskite, chlorite, smectite, illite, quartz, feldspar and plagioclase dominated the clay fraction of dust. These minerals are similar to those reported for the soils of eastern Isfahan. In conclusion, climatic data as well as chemical, physical and mineralogical properties of the dust samples show that, beside the local anthropogenic sources, the soils occurring in eastern Isfahan appear to be the major source of dust in the region.

Increase of sand particle stability and water holding capacity induced by synthesized polymers has been used to improve soil physical properties and wind erosion control. The effect of three water soluble polymers including Karacoat NA58, Acrylic resin EXP174 and polyvinyl acetate, 2 concentration levels of polymers (1 and 6% dry weight) and 2 soil textures (sandy and loamy sand) on saturated hydraulic conductivity and the resistance to penetration of soils were studied. Polymer treatments were injected to soil samples. Results showed that decrease of hydraulic conductivity in loamy sand samples was higher (P<0.01) than sandy soils and decreased 64% compared to the control. Mean hydraulic conductivity (15.4 cm/h) for polyvinyl acetate treatment was lower (P<0.01) than other two acrylic polymers (Karacoat NA58 with the mean of 24 cm/h and Acrylic resin EXP174 with the mean of 25.3 cm/h). Increase of soil penetration resistance in loamy sand treatments was significantly higher than sandy soils (P<0.05), but no significant effect was found for polymer treatments. Both hydraulic conductivity decrease and penetration resistance increase were significantly affected (P<0.01) by 6% concentration level of all polymers used. The maximum polymer penetration (crust thickness) was investigated (70 mm) in sandy soil treated by Karacoat NA58 polymer with 6% concentration. According to the results application of polymer is recommended for sand stabilization and plant growth improvement in desert regions.

Most weather stations in Iran have been installed in the arid lands and they are far from agricultural areas. Previous studies demonstrate that there is significant difference between temperature parameters (maximum and minimum air temperature and dew point temperature) measured in dry and well-watered weather stations and this difference makes an overestimation of reference evapotranspiration (ET0). The objectives of this study were comparison between temperature parameters measured at two dry and well-watered weather stations in arid region of southeast of Tehran, comparison of calculated ET0 with data of these stations and study on the effect of dry weather data on calculated ET0. Data from two weather stations installed in arid and agricultural land for a four-year period (2007-2010) were used and ET0 was calculated with these data. The results demonstrated that the both calculated ET0 in two dry and well-watered weather stations have high adaptation and there is no significant difference between them in 0.05 level. Correction data causes decrease of adaptation and makes significant difference between the two weather stations in maximum air temperature, dew point temperature and calculated ET0.

The study and analysis of non-linear rainfall - runoff procedure to model and determine the different components of the flood hydrograph, including peak flow- the volume of runoff and etc. has long been of interest to hydrologists. In this study, two methods of unit hydrograph and Gary theory were analyzed to estimate flood hydrograph for Shahrchay basin located in West Azerbaijan. For this purpose, several flood hydrograph and precipitation observation data was used to model the mentioned basin. Based on observational data, the parameters of both the unit hydrograph and Grey models were estimated and then the developed model was used to determine the characteristics of the flood hydrograph. Evaluation and comparison of the different specifications of predicted and observed flood hydrograph showed that Grey theory compared to unit hydrograph method has more capabilities in modeling and predicting flood flow hydrograph in basin. Among them, we can note the average error in the volume of flood with values of 32 and 18 percent in the unit hydrograph method and Grey theory, respectively.

Mobile sand is the biggest obstacle to sustainable development in arid and semi-arid regions of Iran. The most effective way to maintain and promote sustainable development is reform and recovery of vegetation in these areas. Mobile sand stabilization has a great influence on soil conservation and minimizes erosion in Taybad. Regarding to existence of reclaimed sandy lands which is caused by the Haloxylon sequence, the rate of change on physical (soil texture and bulk density) and chemical characteristics (EC, pH and CaCO3) and soil erodibility indices (MWD, CR, MCR) were studied in the area. For this purpose, five sites were selected based on Haloxylon age (41, 28, 19 and 11 years old and a control site (no Haloxylon plantation). Considering planting age Haloxylon, the results represent a 24, 14 and 8% reduction, respectively in sand, silt and clay contents. Similarly, bulk density was reduced from 1.57 to 1.37 g/cm-3. Maximum weighted average diameter (2.48 mm) was belonging to 41 years old-Haloxylon plantation while minimum value (0.85 mm) was observed in control site (without any plantation program). Moreover, highest amount of pH (8.4) was observed in the 41 years old-Haloxylon plantation and lowest pH (7.4) was measured in control site. The oldest Haloxylon plantation (41 years old) caused maximum amount of electrical conductivity (EC) (0.7 dS m-1) and the lowest value of EC (0.33 m-1) caused by control treatment. The amount of calcium carbonate changed from 0.33% in control site to 0.6% in 41 years old Haloxylon. The results showed that many of soil physico-chemical properties were improved as Haloxylon afforestations became older.