Journal of Water and Soil Conservation
Year:2017 | Volume:24 | Issue:3|Papers Count:20

Background and Objectives: The protection of the quality of groundwater is very important considering its vast usages in agriculture, industry and as drinking water. Removing groundwater pollution is an expensive process and needs a long time. Therefore, it is necessary to prevent the pollution of groundwater resources using proper methods. One of the usual methods is to investigate areas with high potentials to get polluted. The aim of this study choose a suitable method to identify areas sensitive to pollution in Sarab plain.Materials and Methods: Two models DRASTIC and SINTACS were used in “Sarab” plain to evaluate the pollution of groundwater resources. First, the vulnerability maps of the aquifer were provided for each model. To do this, the information layers of “depth of groundwater table”, “net recharge”, “aquifer media”, “soil media”, “topography”, “the effect of vadose zone” and “hydraulic conductivity of the aquifer” were prepared in GIS. As the next step, the land use parameter was combined with the vulnerability maps, to prepare risk assessment maps. Also, to consider hydrogeological condition of the studied area, AHP method was used to correctly evaluate the weights and the ranks of the effective parameters and sub-parameters in DRASTICLU and SINTACSLU modified models. The correlation coefficient between the concentration of the Nitrate in groundwater and the calculated indexes for the studied area was calculated using linear regression.Results: Based on DRASTIC map, 82.62% of the studied area has medium vulnerability potential. However, 14.43% and 12.94% of the area have low to medium and medium to high vulnerability potential respectively. On the other hand, based on SINTACS maps, the vulnerability potential in 76.48% and 23.52% of the studied area is medium to high and low respectively. Also, according to the results of DRASTICLU index, 24.10%, 48.97% and 24.86% of the studied area are evaluated with low, medium and high risk respectively. However, based on SINTACSLU map, 55.35%, 40.82% of Sarab plain are located in areas with medium and high risk respectively. Besides, according to AHP-DRASTICLU index 7.81%, 50.86%, 37.52% and 3.74% of the studied plain are evaluated as areas with very low, low, medium and high risk respectively. AHP-SINTACSLU index shows similar results to AHP-DRASTICLU index.Conclusion: To be able to choose the best index to evaluate the potential of vulnerability and risk for Sarab plain, the correlations between Nitrate concentration in groundwater on one hand and the amount of each of the used indexes were investigated. According to the results, DRASTIC index with R2=0.40 has the highest correlation among the investigated indexes. However, regarding risk evaluation, AHP-DRASTICLU index has the highest correlation, with R2=0.56. Therefore, to evaluate pollution vulnerability and risk in Sarab plain, these two indexes are the most accurate and trustable.

Background and Objectives: One of the highest losses due to natural disasters is bank erosion. Rivers affected by erosion and sedimentation are subject to various changes such as change of direction, movement in transverse and longitudinal directions, bed level changes and transformation of geometric features. There are several methods to protect the bank in the outer arc, spur dikes are one of thebest and most economical methods used in most parts of the world. In this study, flow and sedimentpatterns in a 90 degree mild bendwith and without spur dikes by changing the position and length of the spur dikes with Configurations 15%, 20% and 25% of the flume width was examined using numerical model CCHE2D and by considering the hydraulic performance of spur dikes the optimum combination of parameters, length and position of spur dike in the bend were investigated.Materials and Methods: The bend used in the numerical simulation in this study isa 90 degree mild bend flume with 70 cm width in hydraulic laboratory of Shahid Chamran University. In order to simulate the flow and sedimentpattern the numerical model CCHE2D was used in this study. This model is a two-dimensional hydrodynamic model which has been prepared and developed at the International Science and hydraulic center of Mississippi School of Computational Engineering in America.Results: Hydraulic and sedimentary results were verified by comparing the simulated results by model with experimental results. The results indicate the numerical models high capability in simulating the flow and sediment pattern in the bend. Comparison of the model and experimental velocity results indicates an accuracy of more than 94 percent. The sediment validation also indicated that the models accuracy in estimating the sediment erosion and deposition is over 90%.Conclusion: The results show that by increasing the length of the spur dikes, the maximum velocity and depth of erosion and sedimentation also increases. For example, the maximum scour depth of spur dikes with length equal to 15 and 20 percent of flume width compared to spur dikes with 25 percent of flume width length decreases 44% and 33% respectively. Also the maximum velocity of spur dikes with 15 and 20 percent of flume width length decreases 9% and 16% respectively compared to spur dikes with 25 percent of flume width length. The results show that the erosion and sedimentation pattern of spur dikes with length equal to 20% of flume width is preferred. Because, firstly they divert the flow to the center of the main channel with causing the least changes in the channel bed. Secondly, the spur dikes with 15% and 25% of the channel width length cause a massive volume of sedimentation in the inner arc of bend.

Background and Objectives: Landslides are significant natural geologic hazard around the world. Expansion of urban and man-made structures into potentially hazardous areas leads to extensive damage to infrastructure and occasionally results in loss of life every year. Identification of factor affecting existing of landslide as well as its zonation in the given watershed is one of the basic tools for landslide control and selection of appropriate and effective solution as well. Thus, a research study with objective of recognizing factor affecting landslide and determination of lands with hypothential to its occurrence was conducted to prepare landslide zonation map for the Sorkhoon watershed using Dempster-shafer and frequency ratio models.Materials and Methods: To reach this goal, after preparing of Landslide inventory map using field survey and aerial photo interpretation, data layers of distance from stream, distance from faults, elevation, slope, aspect, Topography wetness index (TWI), distance from roads, land use, lithology and Stream Power index (SPI) as Factors affecting landslides were selected and after applying Dempster-shafer and frequency ratio methods the final Landslide Hazard zoning was prepared. For calculating of weight of affective factors, was used the analytic hierarchy process in the software of expert choice. To validation of used methods the ROC curve was used.Results: The main factors that caused the landslides in this area based on field observations and Expertise opinions include lithology, distance from roads and slope, respectively, with scores (0.181, 0.163, 0.145) and vis-à-vis factors of elevation, slope and topography wetness index (TWI) respectively with scores (0.018, 0.036, 0.054) have the lowest impact on landslides. According to the results, frequency ratio models have obtained higher AUC (0.927) as compared to the Dempster-shafer (0.858) that shows the high correlation between hazard map and distribution map landslide inventory map and better evaluation of frequency ratio toward Dempster-shafer model.Conclusion: The results of the validation showed that the frequency ratio model has higher efficiency and accuracy toward Dempster-shafer model for preparing of zonation map. Based on the results of the frequency ratio model 21128200 square meters (7.05 percentage) of the region located in the very low risk class, 67, 144, 500 square meters (20.45 percentage) of the area located in the low risk class, 90, 113, 400 square meters (27.45 percentage) located in the moderate Risk class, 91733400 square meters (27.94 percentage) of the area located in the high class and finally 56.160000 square meters (17.11 percentage) of the area located in the very high risk class.

Background and Objectives: One of the most important assumptions in the modeling of time series, it is to be stationary. The amount of stationary can be various, so that different definitions exist such as first order and second order stationary and strong and strict stationary. Therefore, this study cover the effect of differencing on the stationary value as well as the precision of the ARMA, ARIMA and SARIMA models in the modeling and monthly prediction of time series.Materials and Methods: For this purpose, 96 years data of lake level, which is monthly measurement related to Michigan-Huron Lake on the border of United States and Canada, are used. The 76-years of primary utilized for training and the rest of 20-years are used for validation. Firstly, the existing of the trend and period components in the time-series were assessed using Fischer and man-Kendal tests. These two components are the main factors in the appearance of non-stationary in time series. Therefore seasonal differencing, non-seasonal differencing and both of them at same time were measured and their results were compared by non- differencing data. To assessment of achieved time-series differencing, the ACF diagram and generalized Dicky-Fouler test were utilized. The type and amount of required parameters in different models were determined by ACF diagram. Then, each of series was modeled and predicted using appropriate model. The results indicated that there is not a certain trend and period in series. However, the using of seasonal differencing increased the stationary but non-seasonal differencing lead to non-stationary of these time series. The most increasing in stationary was indicated by using of seasonal and non-seasonal differencing. Due to ACF diagram, using both of differencing results in use of seasonal parameters in model. Therefore, series without differencing with ARMA model and series with seasonal differencing with SARIMA are modeled.Results: The investigations showed the concurrent using of seasonal and non-seasonal differencing has the most impact on the rate of getting stationary alignment of the Lake in compare with other methods. As a result, the numbers of model needed to achieve the most accurate predictions were reduced in large scale. In such a way in non-differencing situation, 1444 model of ARMA were needed that this amount in situation of seasonal differencing and non-seasonal differencing were reduced in 64 models of SARIMA. On the other hand, by reducing much more number of parameters (two parameters) in SARIMA model, similar result is even better than ARMA model with 21 parameters.Conclusion: The results showed that the more making stationary of monthly lake level which itself is stationary, reduces the number of models and the number of model's parameters needed to achieve the best outcome too much. For this purpose, combined differencing made the series stationary more than the other methods.

Background and Objectives: Application of different organic materials in organic agriculture may change the status of plant nutrients in deficient soils. Arid soils of Iran may have a considerable content of potassium (K); but their K content is decreasing due to intensive agriculture. This K deficiency may be alleviated by different organic materials application in organic agriculture.Materials and Methods: In the current investigation, a completely randomized experiment was done with application of four plant residues and their produced biochars to a calcareous soil and their effect on different forms of K. Three grams of wheat straw, corn straw, rice bran and licorice root residue and their produced biochars was added to 100 g of a clay loam calcareous soil and incubated for 90 days at 22±2°C and 50 % of saturation moisture content. The soil samples were air-dried and sieved and pH, electrical conductivity and contents of soluble, exchangeable, non-exchangeable, HNO3-extractable K and K release rate from soil minerals were determined.Results: Results indicated that plant residues had no effect on soil pH, but all biochars increased soil pH (mean of 0.07). Soil EC was increased with application of wheat and corn straws and conversion of plant residues to biochars had more effect on soil salinity. Licorice root residue and its biochar had no effect on the content of different K forms; but other plant residues and their biochars increased soluble, exchangeable and HNO3-extractable K in the order of wheat residue>corn residue>rice bran. On average, biochars had more effect than plant residues on the content of soluble, exchangeable and HNO3-extractable K (212, 269 and 286 mg kg-1, respectively). The content of HNO3-extractable K was not affected with plant residues and their biochars (except for corn straw). Wheat and corn straws and rice bran released 286, 217 and 146 mg K kg-1, respectively; and their biochars released 637, 429 and 290 mg K kg-1, respectively from K-bearing minerals and this may be due to the effect of organic molecules and non-organic cations of organic materials on mineral weathering and K release.Conclusion: It is concluded that application of plant residues and their biochars may have significant effects on soil K status and alleviation of K deficiency and the role of biochar is more important than primary plant residues. On the other hand, increase in soil salinity and pH especially in calcareous soils of arid land should be take into consideration.

Background and Objectives: Phosphorus is a finite resource and an essential nutrient for sustaining all forms of life in aquatic environment. It was also found in various chemical forms which might be gradually released into water column and exacerbate eutrophic condition in rivers and lakes. Thus, P fractionations provide useful insight into risk posed by P-associated sediments to aquatic environment. There is little information available regarding P chemical forms and its bioavailability in aquatic ecosystems in Iran and there was limited number of publications regarding the evaluation of P forms release from river sediments. The published reports and field observations clearly insist on the phytoplankton growth and some dense algal blooms occurring during years with low water in river sediments. Thus, evaluation of P in aquatic environments by algal bioassay and threats of losing biodiversity could be essential.Materials and Methods: Thirty four river sediments from seven main rivers of the Urmia Lake basin were taken from depth of 0-10 cm for algae (Senedesmus Obliquus) bioavailable P evaluation by sequential chemical extraction. Phosphorous pools in these sediments extracted using operationally defined method that includes as exchangeable (EXCH-P), iron and aluminum oxide-bound (Fe/Al-P), calcium bound (Ca-P) and residual P (RES-P). Principle component analysis was conducted to determine the important properties and chemical forms of P in sediment samples. Algal bioassay was carried out to distinguish the bioavailable P fractions. Hierarchical cluster analysis and Pearson simple correlation were applied for selection of the samples of algal assay and determining bioavailable P fraction, respectively.Results: Generally, sediments had coarse texture with high amount of silt and very fine sand. Principle component analysis indicates that particle and carbonate-related properties have significant role in determination of sediments properties. The average rank order of P extraction by sequential extraction were, Ca-P>RES-P>Fe/Al-P>EXCH-P for all rivers except the Simineh Chai. Simineh Chai sediments had higher concentration of Fe/Al-P than RES-P, indicating possible pollution in the river. There was significant correlation between Fe/Al-P (r=0.947, P<0.0001), EXCH-P (r=0.668, P<0.01) and RES-P (R=0.563, P<0.05) with Senedesmus Obliquusgrowth in studied sediments. However, Ca-P did show no correlation with algal growth during 30 day incubation period.Conclusion: Analysis of P fractions in sediments by sequential chemical extraction shows that Fe/Al-P fraction provided higher potential bioavailability and due to significant correlation with algal growth is proper indicator to evaluate river health and eutrophication of Urmia Lake. River sediment of Urmia Lake had high ability to retain P in Ca-P fraction which could be recalcitrant P pool for algal growth.

Background and Objectives: Soil is a key resource that control the cycles of water, biota and geochemicals and the greatest organic matter reservoir. Little information is available about the effects of grazing on different forms of soil organic carbon in Khuzestan province pastures. Therefore, this study was conducted to evaluate the effects of grazing management on amount and forms of organic carbon in some pasture soils from Peneti plain of Izeh area in Khuzestan province.Materials and Methods: Accordingly, two adjacent pastures with different management (grazing and grazing exclusion) around the Izeh city were selected and then, random soil samples were taken from the surface (0 to 20 cm) and subsurface (20 to 40 cm) in 15 points. After air drying the soil samples and passing them through a 2 mm sieve, physical, chemical properties and forms of organic carbon including total organic carbon (TOC), permanganateoxidizable carbon (POXC), fine particulate organic carbon (FPOC) and coarse particulate organic carbon (CPOC), dissolved organic carbon (DOC) and microbial biomass carbon (MBC) of the soils were measured.Results: The results showed that grazing management has increased soil organic matter of surface and subsurface soils the values were statistically significant in the surface layers and increased the amounts of TOC (from 8.33 to 9.53 g kg-1), DOC (from 9.46 to 10.86 g L-1), MBC (from 418.1 to 456.2 mg kg-1), POXC (from 974.25 to 1035.3 mg kg-1), FPOC (from 430.6 to 450.7 mg kg-1) and CPOC (from 680.10 to 701.4 mg kg-1), but despite the increase in organic matter contents of subsurface soils the difference was not statistically significant. The effect of management practices, in order to have a significant effect to lower parts of the soil, it requires a longer period management. Comparing the biomass upon non-grazing (405 gm-2) and grazed (117 gm-2) areas, indicates a good condition of vegetation in the non-grazing and the effectiveness of enclosure in rehabilitation of pastures in the study area.Conclusion: The results showed that MBC, DOC and POXC are more sensitive than other forms of organic carbon to grazing management. They are more appropriate indicators for grazing management on organic carbon quality being added to the soil. Also, based on carbon stratification ratio index (CSRI), regarding different forms of organic carbon in the study area, non-grazing was one of the most proper and efficient management practices which improved soil quality. Accordingly, it seems that non-grazing practices should be considered as one of the major programs in renewable natural resources plans. On the other hand, the results indicate adverse effects of grazing on the quality of soil organic matter endangering the long-term sustainable production in pastures.

Background and Objectives: Overuse of natural resources exacerbates soil loss and sediment yield and has caused exceeding allowable rates of soil erosion. Many on-and off-site problems occurred due to irregular human use of natural resources leading to increasing sediment loads in the watersheds. Intensification of sediment yield leads to many intra and extra problems in the watersheds. The awareness on important and susceptible areas of sediment transport is therefore an essential tool to design effective strategies in management of sediment yield and transport in watersheds. Sediment connectivity is one of the most important concepts in this context to investigate sediment transfer between different locations and potential transfer of sediment particle across (between hillslopes, between channel and hillslope, within channel) a watershed. This research was therefore planned to investigate spatial and temporal variations of structural sediment connectivity in 1990, 2001 and 2014 years in Taham-Chai Watershed in Zanjan province, Iran.Materials and Methods: In this study; slope, flow direction and flow accumulation layers have been made using digital elevation model (DEM) in 1: 25000 scale and 100 m2 cell sizes. The C factor layer has been made using Landsat images in 1990, 2001 and 2014 years based on the NDVI. All layers along with the main stream network layer of the watershed have been used under two scenarios viz. the potential connection of sediment between hillslopes and catchment outlet and sediment connection between hillslopes and main channels to estimate structural sediment connectivity.Results: The results showed that the structural sediment connectivity based on the first scenario varied from -8.24 to -8.06 and 1.02 and 1.18 for min and max values, respectively. The Structural sediment connectivity index has decreased from -5 to -7 during 1990 until 2014. Regarding structural sediment connectivity maps, connectivity is high in western, southwestern and northwestern sections than other parts of the study area. The net spatial difference of structural sediment coactivity index values has been changed in the range of 0.9 from 2001 until 2014 which it is decreasing in the most sections of the study area and led to a decrease in structural sediment connectivity index. The results of the second scenario showed that the north and southwestern sections of the watershed along with central sections have low structural connectivity because of far distance from the channel network and slight topography respectively which these results are also consistent with results of first scenario. In addition, south, eastern and northeastern sections of the watershed have formed integrated hillslopes which they are prone to transfer sediment to the channel network.Conclusion: Overall, on the basis of the results there is a possibility to investigate structural sediment connectivity and its temporal and spatial variations in the watershed. It also helps distinguish homogeneous sections by similar potential in sediment transport. Accordingly, investigation of structural sediment connectivity causes making conservative measurements and purposeful managerial decisions about sediment yield and transfer with respect to priority of homogeneous sections and financial and equipment constraints especially in countries such as Iran.

Background and Objectives: Developing of techniques for regional flood frequency estimation in ungauged sites is one of the foremost goals of contemporary hydrology. The flood frequency evaluation for ungauged catchments is usually approached by deriving suitable statistical relationships (models) between flood statistics and basins characteristics. Already, several equations have been presented to estimate the flood frequency in different areas such as Karkheh basin. However, due to the complexity of this phenomenon, the relationships have not been capable to simulate the flood frequency with desired accuracy. Accordingly, in this study, in addition to the regression method has been used in the previous studies, the ANN and ANFIS models are applied. In fact, these are a type of black box models without any knowledge of processes within the system, in which inputs are converted into outputs (or output). This situation indicates that this type of new models is actually similar to the regression relations, however, there is further flexibility in adjusting the weights and thus can be used as an replacement to multivariate regressions.Materials and Methods: The study area, including 33 hydrometry stations, is located in the west of Iran. In this study, 27 of the stations for calibration and 6 of the stations for validation were used. To approach a unique model, return period was taken into account as the independent factor.Results: For achieving the best ANN and ANFIS system, different combinations of physiographic with return periods, as input data, has been used. To find the important input factors of the models, sensitivity analysis has been performed in SPSS software. Accordingly, the most important independent variables were including: Return period, area, height, main stream length and slope. In the ANN model, different combinations of these inputs were compared together. It should be noted that for optimizing the connecting weights among different layers of ANN, Genetic algorithms have been used. Consequently, the best selected network is Feed-forward with the structure of 5-10-1 and R2=0.95. In the ANFIS system, with increasing the number of input variables for each of the four membership function, including Triangular, Gaussian, Gaussian2 and trapezoidal, simulation accuracy increases. The best simulation is a triangular function with RMSE=0.1514, R2=0.97 and the number of rules is 243. Finally, by comparing models, The ANFIS model was selected as the best model. The ANFIS has the best accuracy especially in high return period.Conclusion: Where the sub-basins are small and their flood in different return periods is less than 1000 m3/s, the regression model makes a good accordance with real flood. The ANN model has also good performance in low discharges. The regression presents its forecast in the framework of formulas and it is better and more practical for engineers. Generally, The ANFIS model is the best model for all ranges of the discharge and the best tool for prediction enormous flood in Karkheh basin.

Background and Objectives: In open channel junctions development of separation zone at the downstream channels is one of the engineering challenges. Development of separation zone has important role on determination of position of hydraulic structures and also increase of its dimensions caused decreasing of flow area so that leads to more erosion of the bed. As the flow is entered to the channel, flow separated from the wall and a zone with low pressure and vortex is created that is called separation zone. As regards of destructive effects of development of the separation zone, researchers always have focused on this case. The aim of this study is to investigate the effects of factors such as inlet discharge ratio, height of outlets weirs and bed elevation of inlet channels on dimensions of the separation zone in 90 degrees four-branch junction with subcritical flow.Materials and Methods: Experiments were carried out in hydraulic Lab of Tabriz University. The setup consists of an intersection of four identical channels which intersect at right angles. Each channel is made from glass with a width 0.4 m and height 0.5 m. Junction was right-angled and bed of the channels was considered horizontal. In this study effects of different geometric and hydraulic parameters such as height of the outlet weirs, bed elevation of the lateral channel and inlet discharge ratio on characteristics of the separation zone in outlet channels in 90 degrees four-branch junction with two inlet flows and two outlet flows was investigated experimentally. In order to investigate the flow pattern were used pigment and sawdust and dimensions of the separation zone were measured by ruler and meter.Results and Discussion: The results revealed that decreasing height of outlet weirs increases dimensions of the separation zone so that minimum variations of (ratio of length of the separation zone in main outlet channel to channel width) Lx/bxo was about 45 percents. As the bed elevation of lateral channels increases dimensions of the separation zone at the main outlet channel increase which variations of Lx/bxo was between 0.8 to 2.75 but dimensions of the separation zone at the lateral outlet channel decrease and variations of (ratio of length of the separation zone in lateral outlet channel to channel width) Ly/bxo was at the range of 0.2-2. The results also indicated that as the ratio of outlet weir height of the lateral channel to outlet weir height of the main channel increases, dimensions of the separation zone in both lateral and main outlet channels increase so that variations of Ls/bxo for both main and lateral channels were at0.2-1.4 and 0.2-2, respectively. Although the dimensions of the separation zone change with respect to different conditions but width to length ratios in lateral and main outlet channels were 0.16 and 0.25, respectively. Finally in order to calculate the dimension of the separation zone, regression equations were presented so that experimental and analytical results had good agreement.Conclusion: In this research effect of the inlet discharge ratio, height of the outlet weirs and bed elevation of the lateral channels on dimensions of the separation zone in 90 degrees open channel junctions was investigated. Results showed that as increase of the inlet discharge ratio and height of the outlet weirs, dimensions of the separation zone increased. Increase of the bed elevation of the lateral channel increased dimensions of the separation zone in main outlet channel while decreased dimensions of the separation zone in lateral outlet channel. As increased of cy/cx dimensions of the separation zone in both outlet channels increased.

Background and Objectives: Agriculture is one of the most sensitive sectors in terms of climate change, due to its high dependence on meteorological parameters. By increasing air temperature evaporative power of the atmosphere will be increased and crop growth period will be decreased. Under climate change situation crop yield and crop water requirement will be changed. Changes in these parameters under climate change scenarios can be estimated using simultaneous application of climate change and crop growth simulation models. In this study the impact of climate change on potential evapotranspiration of an autumn crop (barley) and a spring crop (maize) in three stations in different climatic regions of Kermanshah Province for the upcoming period of 2046-2064 were examined.Materials and Methods: The study was carried out in three phases. In the first phase meteorological parameters in the future were estimated based on scenarios of A1B, A2 and B1 of HADCM3 climate change model and downscaled using LARS-WG package software. In the second phase reference crop evapotranspiration under current and the future situations was calculated using the FAO Penman-Monteith formula and compared together. In the third phase growth of studied crops were simulated by AquaCrop software using calibrated crop parameters in the region and based on current and future weather data sets. According to the model outputs seasonal evapotranspiration, maximum daily evapotranspiration and length of growth period under current and future climates were compared.Results: Results of first phase indicated the increasing in the minimum and maximum temperatures and fluctuations in rainfall and sunshine hours compared to the base period (1992-2010). Meanwhile, in the future potential reference crop evapotranspiration in all three stations will be increased. According to the results of this study seasonal evapotranspiration of maize in the future will be increased by 25-27% in Songhor, 16-18% in Kermanshah and 5-7% in Sarpol_e_Zahab. The estimated maximum daily evapotranspiration of maize in the future will be increased by 37-38% in Songhor, 19-20% in Kermanshah and 19-21% in Sarpol_e_Zahab. On the effect of climate change growth period of maize will be decreased by 20, 14 and 10 days respectively in Songhor, Kermanshah and Sarpol_e_Zahab. The trend of changes in the studied parameters for barley was the same as maize but the rate of changes was estimated less.Conclusion: Results of simulation indicated the increasing of seasonal potential evapotranspiration and maximum daily evapotranspiration and decreasing of crop growth period in all three stations under climate change scenarios. The effect of climate change on studied parameters for both crops in Songhor station (cold region) will be higher than Kermanshah (mild) and much more than Sarpol_e_Zahab (tropical). In addition, the percentage of changes in evapotranspiration of spring crop (maize) under climate change will be more than winter crop (barley).

Background and Objectives: In urban catchment because of developed conditions, the amount of impervious area increases which tends to increase runoff volume, peak discharge rate and decrease of infiltration volume. Increase in impervious surfaces to reduce the influence on subsurface flow and base flow or flow of dry air is both concrete and natural channel. In Bandar Abbas city measured and recorded flood in the region is particularly important because of the lack of hydrometric station or any base to measure and record flood. The main objective of the study was evaluate the status of surface water collection system is part of Bandar Abbas city by SWMM model. Addition to investigating flood, weaknesses identified in the network to collect surface runoff Moreover, the critical parameters in the model were determined.Materials and Methods: In the first for runoff simulation and to determine sensitive point flooded was used of SWMM Model. The coefficient of determination (R2) and Nash Sutcliffe (NS) for calibration and validation the model were used in five events 2014/01/19; 2015/03/11; 2015/12/25; 2014/01/07 and 2016/01/03. Depth and velocity measured in outlet basin by current meter gauging. Also to determine sensitive point flooded of Bandar Abbas city used of way measured field with help Eshel. In order to sensitivity analysis were evaluated nine effective parameters in the model using Nash-Sutcliffe (NS).Results: The results showed that the most sensitive Respectively parameters based on the coefficient NS impervious present area, Roughness coefficient impervious area, width, Storage the depth of impervious areas, sub basin areas, slope percent, Storage areas percent without surface, Storage the depth of pervious areas and Roughness coefficient pervious area. The results obtained from model calibration (respectively calibration average coefficient NS 0.75 and coefficient R2 between 0.83) showed good agreement with the observed data. Validation results (mean coefficient NS 0.79 and coefficient R2 between 0.92) showed high accuracy for this area. It was found flooding in some areas was due to lack of adequate capacity conduit. However In some places model confirms that sufficient channel capacities, There were flooding due to the blockage Rubbish is in these places.Conclusion: The results evaluate showed discharge runoff simulation and estimated SWMM model has a good compliance (adapt ate). According to the ability of each sub-basin runoff simulation model and determine the critical points of this model is suitable to be used in city areas without Hydrometrics station. But the model must be calibrated. So we can use this model to predict the risk of flooding, design and estimate the amount and cost of drainage, urban coastal watershed management and prioritizing fixing the problem areas to be flooded.

Background and Objectives: Because of deforestation and reduction of forest areas, plantation is a vital issue for now and the future. The evaluation of planted species is very important to creation of forests with better quality and quantity in the future. Soils, as an important part of the ecosystems, are affected by tree species with differences aboveground and below ground biomass, under same field condition. Biological properties are good indices to assessment of soil quality and health. In this study the effects of different forest covers including natural forest, hardwoods and softwoods plantations, on variability of fine roots biomass, ecological group's earthworm's density/biomass and nematodes abundance were considered.Materials and Methods: Soil samples were excavated in sixteen points from 0-15 cm (top soil) depth, for each forest covers including Carpinus betulus (hornbeam) - Parrotia persica (iron wood) as a natural stand, Fraxinus excelsior (ash), Acer velutinum (maple) hardwoods and Pinus brutia(pine), Cupressus sempervirens (cypress) softwoods plantations, located in Wood and Paper Company of Mazandaran. Soil moisture, pH, organic carbon, total nitrogen and biological indices (fine roots biomass, earthworm's density/biomass and nematodes abundance) were measured and recorded at the laboratory.Results: ANOVA results for soil physico-chemical properties showed significant statistical differences related to forest covers. So that the highest values of soil moisture, organic carbon and C/N ratio were found under pine plantation. Also the higher values of soil pH and total nitrogen were detected inCarpinus betulus - Parrotia persica natural stand. Greater amounts of fine root biomass (89.68 g m-2), earthworm's density (1.81 n m-2) /biomass (24.17 mg m-2) and nematodes abundance (603.37 n m-2) were found in Carpinus betulus - Parrotia persica natural stand. Also maximum epigeic density (1.43 n m-2) /biomass (19.25 mg m-2), were found under Carpinus betulus - Parrotia persicanatural stand and ash plantation. Higher anecic earthworm' s density (0.37 n m-2) /biomass (4.92 mg m-2) recorded in Carpinus betulus - Parrotia persica natural stand. The endogeic species were not observed under different forest covers. Greater amounts of nematodes abundance (603.37 n m-2) were recorded in Carpinus betulus - Parrotia persicanatural stand. The finding of correlation between biological indices and other studied properties indicating that biological characters are influenced by soil water content and chemistry under different forest covers.Conclusion: The findings of this study are showing the considerable effect of natural forest covers on soil biological properties and quality. In addition, in degraded areas of northern Iran, planting of Fraxinus excelsior species can be considered due to improvement and conservation of soil biological indices, quality and health.

Background and Objectives: The study of heavy metals is particularly important because they are not decomposable and also have harmful physiological effects on organisms even at low concentrations. Cadmium is a heavy metal which may entered water, soil, plants and ultimately the human and animal's food chain from various sources and it can cause serious damages. Biological fertilizers are consisted of concentrated population of beneficial microorganisms or their metabolic products that introduced into soil to improve soil fertility and plant nutrition in sustainable agriculture. Vermicompost and its derived aqua products (i.e. vermiwash and tea vermicompost) are as biofertilizers. Vermiwash is a complex of materials which are excreted from both earthworm substrate and their body. Vermiwash is rich in vitamins, hormones, enzymes, macro- and micronutrients which can help plants for efficient growth. vermiwash, could be used an organic liquid fertilizer as foliar spray in agriculture. The aim of this study was to evaluate the effect of liquid organic fertilizer on growth, cadmium and macronutrients uptake of Spinach in a cadmium polluted soil.Materials and Methods: A greenhouse experiment was conducted with factorial arrangement in a completely randomized design with two factors and tree replications in a cadmium contaminated calcareous soil. Treatments were consisted of four levels of vermiwash (0, 25, 50 and 100 ml per kg of soil) and four levels of cadmium (control 5, 10, 20 and 40 mg Cd kg-1. Before cultivation soil was used and its characteristics along with vermicompost were analyzed by standard methods. Seeds of spinach (Spinacea oleracea L.var. inermis) were planted in pots. After eight weeks of planting, wet and dry weights, concentrations and uptake of nitrogen, potassium, phosphorus and cadmium of plant were measured.Results: The results of this study indicated that vermiwash is effective in improving of growth and yield of plant. The lowest dry weight was observed in control (without vermiwash) and the level of 40 mg Cd per kg of soil and the highest of them was observed in 50 ml vermiwash and the level of 40 mg Cd per kg of soil. In all Cd levels, the concentration and uptake of nitrogen and phosphorus by plants were increased. Vermiwash had no significant effect on cadmium and potassium concentration of plant.Conclusion: Vermiwash application increased yield and macronutrient uptake by Spinach in Cd contaminated soil. Vemiwash could be used as a plant growth fertilizer. Further investigations will be useful and recommended in field condition.

Background and Objectives: Accurate planning is very important for optimized use of water resources in agricultural sector due to climate condition of Iran. According to the research results, drought and salinity are two factors limiting agricultural production in arid and semiarid. Since changing drought or salinity adjust or increase other effect on plant, it is necessary evaluating combined effects of drought and salinity on plants such as date palm. In this reseach, the effect of water stress and salinity were studied in vegetative growth stage of Barhee date.Materials and Methods: This research was carried out in factorial method based on randomized complete design with three replications onBarhee juvenile date palms. The treatments were three irrigation depths of 100%, 85% and 70% of plant water requirement and three irrigation water salinities of 2.5, 8 and 12 dS/m. The irrigation depth was calculated by measuring soil moisture. The production functions of water-salinity-dry matter yield were determined in linear, Cobb-Douglas, quadratic and transcendental equations. Five statistical indices of adjusted coefficient of determination (R2 adj), modeling efficiency (EF), maximum error (ME), normalized root mean square error (nRMSE) and coefficient of residual mass (CRM) were used in evaluation of models.Results: The results showed that irrigation depth, water salinity and interaction of irrigation depth and water salinity had significant effect on all vegetative characters of plant except shoot relative water content. Decreasing irrigation depth from 100% to 85% of plant water requirement showed non-significant decrease in mean of shoot wet and dry matter that were only 5.0 and 5.6 percent, respectively. Amounts of these characters decreased significantly 26.3 and 24.4 percent, respectively, in irrigation depth equal 70% of plant water requirement. While, increasing water salinity from 2.5 to 8 dS/m was caused significant decrease in mean of shoot wet and dry matter that were 44.0 and 42.0 percent, respectively. Amounts of these characters decreased 54.1 and 52.0 percent, respectively, in irrigation with water 12 dS/m. The most amounts of plant vegetative characteristics obtained from water salinity of 2.5 dS/m and irrigation depth equal 100% of plant water requirement. This treatment had significantly different with other treatments expect water salinity of 2.5 dS/m and irrigation depth equal 85% of plant water requirement.Conclusion: The Barhee juvenile date palms can be irrigated with 85% of water requirement when water salinity is 2.5 dS/m. The comparison of production functions of water-salinity-dry matter yield showed that quadratic equation had more accuracy than other equations in estimation of dry matter yield in vegetative growth phase of Barhee date palm. All equations estimated shoot dry matter less than actual amount expect quadratic equation.

Background and Objectives: Spatial variability of soil properties is related to environmental factors such as climate, slope position, topography, slope gradient, elevation, parent material and vegetation. Topography variability and soil formation cause the significant differences in soil characteristics in a hillslope. Topography affects the amount of nutrients, including potassium (K) in the soil. Therefore, knowledge of variability in soil K availability to achieve better production and sustainable management is essential. The relationship of quantityintensity (Q/I) offers a relatively full of soil K status. The present study was to evaluate the effect of topography on K quantity- intensity parameters using the six horizons in both depths on a sequence in Shahrekord plain.Materials and Methods: Soil samples were air dried, to pass a 2 mm sieve and then, selected physical and chemical properties of soil were measured by laboratory standard methods. In these samples Q/I parameters including activity ratio at equilibrium (AR0), labile K (DK0), potential buffering capacity (PBCK) and hardly exchangeable K (Kx) also K forms were determined.Results: The results showed that the effect of topography on K quantity- intensity parameters in both depths was significant (P<0.05). The K activity ratio in the surface soils ranged from 0.012-0.057 (mmol L-1) 0.5. The labile K surface soil ranged from 1.46-0.34 (mmol kg-1). K potential buffering capacity was 36.79-22.54 (mmol kg-1) / (mmol L-1) 0.5 in the surface horizons. The hardly exchangeable K (Kx) varied in soils surface 2.39-0.10 (mmol kg-1). In soils located on the lower slope, the amount DK0 (0.90-1.46 mmol kg-1) and AR0 (0.035-0.055 mmol L-1) 0.5 higher than the soil located at upper slope (DK0 in the range of 0.34-0.53 (mmol kg-1) and AR0 with a range of 0.011-0.014 mmol L-1) 0.5, respectively. But PBCK and AR0 have different values at different slopes. Study the correlation between Q/I parameters and soil properties suggested that correlation was observed between AR0 with organic carbon in surface layers (r=0.74**), CEC (r=0.78**) and clay (r=0.62**). Correlation between ΔK0 and CEC (r=0.80**) and clay (r=0.66**) was also significant. In subsoil horizon significant correlation was found between PBCK with CEC (r=0.56*) and clay (r=0.70**); between DK0 with exchangeable K (r=0.83**) and organic carbon (r=0.89**).Conclusion: The results showed that topography caused changes in the soil properties, especially clay, organic carbon and CEC, therefore, can affect the quantity-intensity potassium.

Background and Objectives: Water storage depletion is an increasing hydrological threat to agricultural production and socio-economic stability across the globe. It is fast approaching threshold levels especially in arid/semiarid regions like IRAN with low precipitation and excessive evapotranspiration (ET). The more accurate for the estimating evapotranspiration as one of the most important parameters that cause water loss can be a step towards enhancing human ability to control and manage the water crisis. Unfortunately, with outbreak phenomenon of drought and excessive increase in water consumption and reducing groundwater resources, Qazvin province is facing a water shortage crisis. This paper introduces a new method to increase the accuracy of Evapotranspiration and calibration of rainfall data of Global Land Data Assimilation System (GLDAS) model and also introducing GLDAS Evapotranspiration, rainfall and temperature as a suitable replacement for the records data, especially in regions where have no data and Inaccessible places.Materials and Methods: In this study which was proceed in Qazvin, evapotranspiration and temperature for the years 1379 to 1382 and rainfall for the years 1995 to 2010 has been studied. According to 50-years of rainfall data, years 80-79, 81-80 and 82-81, respectively, were selected as dry, normal and wet crop year. Quantitative indices that have been used to evaluate the results are such as correlation coefficient (R), root mean square error (RMSE), mean bias error (MBE) and Mean Absolute Error (MAE).Results: The results of the GLDAS evapotranspiration data and lysimeter R2=0.95, RMSE=0.68 (mm/month) shows that there is a high correlation between the two data series. In addition to the Evapotranspiration, temperature and precipitation as well as two parameters affecting evapotranspiration were evaluated. The statistical results indicate that R2 is more than 0.9 between air temperature of GLDAS and station and R2=0.67 between precipitation of GLDAS and station data.Conclusion: According to results, using data from evapotranspiration, temperature and precipitation derived from GLDAS model as an alternative to the observational data in areas where have no data is suggested.

Background and Objectives: In the recent years, the effects of economic and environment, resulting from soil erosion and sediment yield is one of the most important joint issues in around the world and watersheds from Iran especially. So many scientists use indirect methods mainly erosion and sediment relations and models. These relations that are usually used in the country were imported and less compatible with the country's conditions. So, when applying these relations, the results should be calibration and statistical validation using observation data, so that if high precision, are used in the same region. The objective of this study was the estimating of the efficiency of universal soil loss equation with measuring observation erosion in study area.Materials and Methods: This study was carried out on the soil dam of the Aij watershed in the Chaharmahal va Bakhtyari province. The six factors of model include: Rain erosivity factor using the rainfall erosivity map, soil erodibility factor by soil sampling in the homogenous units and using the wischmeier's anemograph (1987), slope factor using digital elevation model (DEM), land cover using satellitesimagine, the mean amount 2.75 Mj.mm per hec.yr.hr, 0.24 Mg.hec. Year per hec. MJ. mm, 0.44, 0.43 and 1, respectively. In the following, the amount of sediment using scale was measured for 4 last years.Results: Combining the factors of universal soil loss equation using ARCGIS9.3, the amount of annual soil erosion was estimated about 0.13 tons per hectare per year. On the other hand, using the amount of observed sediment load and sediment delivery ration, the observed erosion calculated about 3.3 tons per hectare per year.Conclusion: The difference of the amount of estimated erosion using soil loss equation with observation erosion showed that, the model has low ability to use in the study area and areas with similar characteristics.