JWSS - Journal of Water and Soil Science

Water is the most crucial factor for agricultural development. Therefore, the economic evaluation of water resources is critical. The purpose of this paper was to determine the economic value of water resources, to evaluate the financial efficiency and to decide on the price of agricultural water in Arak plain. For this purpose, the economic value of water resources for wheat, barley, alfalfa and corn was identified in 2015- 2016, using the mathematical model developed in this research. The results showed that the financial efficiency was calculated for three alternatives: free-cost water, water cost equal to the 10% of the calculated price and water cost equal to the exact calculated price.  The irrigation efficiency of 40% financial efficiency was 2.38%, 1.68% and 0.47% , respectively, for the  aformentioned methods, and  the irrigation efficiency of 70% financial efficiency was 2.07, 1.92 and 0.71, respectively. Also, the sensitivity analysis of the financial efficiency was performed, with 10% change in the farmers income and costs. The results also revealed that irrigation efficiency and financial efficiency were not aligned when farmers had free water; however, they were aligned when the farmer paid 10% of the calculated price. Financial efficiency was more sensitive to changes in the farmers income when compared to the changes in costs.

Long-term drought effect is one of the main factors of global climate change, with  consequences for soil biogeochemical cycling of carbon and nitrogen and the  function of soil ecosystem under drought conditions. We hypothesized that 1) the Bromus inermis, Dactylis glomerata and festuca arundinacea species would differ in their rhizosphere responses to drought and 2) combined plant species and drought would have offsetting effects on the  soil biological traits. We tested these hypotheses at the long-term drought field expreiment at the  Lavark Farm of Isfahan University of Technology by analyzing soil microbial biomass carbon and nitrogen and activity of β-glucosaminidase in the rhizosphere of Bromus inermis, Dactylis glomerata and festuca arundinacea species. Soil microbial biomass carbon and nitrogen responses to drought depended on plant species,  such that the highest MBC was recorded in the Bromus inermis rhizosphere, while the  lowest was in the Dactylis glomerata rhizosphere, thereby suggesting the greater microbial sensitivity to drought in the Dactylis glomerata rhizosphere. Genotype variations (drought tolerate and sensitive) mostly affected the change in the β-glucosaminidase activity, but they were not significantly affected by drought treatment and plant species. In general, the positive effects of  the plant genotype could offset the negative consequences of drought for soil microbial biomass and traits.

Erosion causes the reduction and degradation and the soil fertility; one of its most important consequences, endangering the food security of the inhabitants of the area. Therefore, to reduce erosion, it needs to be controlled and managed using good soil conservation methods. It is only necessary to manage and control the full impact of the factors affecting the soil first. If there is a critical state of erosion in the four watersheds, identifying the precise location of erosion will be done quickly and with less cost; thus, further erosion control and counter-operation will be feasible. In this study, geographic information system and decision making models of AHP and ANP in Bagheran region of Birjand were used to determine the erosion prone areas. First, 10 effective criteria including rain, slope, slope direction, soil, geology, permeability, vegetation, land use, distance from road and village, were determined on the erosion in the area based on the expert opinion and library studies. Next, the questionnaires were sent to experts to explore g the impact of the criteria on erosion; after completing the questionnaires based on Expert Choice and Supper Decision software, the relative importance of the criteria was obtained. The maps were then compiled and integrated according to the relative importance of the criteria. Rainfall factor had the greatest impact on the erodibility of the area in the AHP method with the relative importance of 0.21 and the   vegetation criterion with the weight of 0.158 in the ANP method had the most impact on the determination of erosion prone areas. Finally, the erodibility map of the area was obtained based on the presented models. Subsequently, the region was classified into five classes of erosion susceptibility, with areas of moderate sensitivity having the most area in both models. In the lower and upper classes, the ANP method performed better; in the middle classes the AHP method performed better.

Changes in soil infiltration cause changes in irrigation efficiencies; therefore, estimating it in calculating irrigation efficiencies provides a more accurate estimate of irrigation performance indicators. In a study conducted on ARC2-7 farm in Amirkabir agro-industry in the 2010-2011 crop year, during four irrigations; two furrows were selected in terms of uniform infiltration and variable infiltration with a length of 140 and a width of 1.83 m. In the furrow assuming uniform infiltration two flume type II, at the beginning and end of it, were installed and the cumulative infiltration was determined by the volume balance method. The furrow with variable conditions was divided into four sections by installing five flumes. By examining the spatial variations of the mean cumulative infiltration, its value decreased from the first to the fourth section for the first irrigation by 15% and for the subsequent irrigations by 13%. Temporal changes of cumulative infiltration decreased by 27 and 30% for the first and second sections and by 26% for the third and fourth sections. An 11% increase in the average weight of the aggregate diameter and a 7% decrease in bulk density indicate physical changes in the soil. Surface runoff losses increased from 8 to 18.77% in the furrow assuming uniform infiltration and from 10.91 to 19.77% in the furrow with variable infiltration, and application efficiency decreased by 6%.

Nowadays, the prediction of river discharge is one of the important issues in hydrology and water resources; the results of daily river discharge pattern could be used in the management of water resources and hydraulic structures and flood prediction. In this research, Gene Expression Programming (GEP), parametric Linear Regression (LR), parametric Nonlinear Regression (NLR) and non-parametric K- Nearest Neighbor (K-NN) were used to predict the average daily discharge of Karun River in Mollasani hydrometric station for the statistical period of 1967-2017. Different combinations of the recorded data were used as the input pattern to predict the mean daily river discharge. The obtained esults  indicated that GEP, with R²= 0.827, RMSE= 59.45 and MAE= 26.64, had a  better performance, as compared to LR, NLR and K-NN methods, at the  validation stage for daily Karun River discharge prediction with 5-day lag, at the Mollasani station. Also, the performance of the models in the maximum discharge prediction showed that all models underestimated the flow discharge in most cases. 

Improper water managements and overuse of surface water and groundwater mainly for agricultural purposes in Iran have led to the drying of many rivers and groundwater. Climate change adds an extra pressure on the water resources. These changes indicate the necessity of adjustment in water management plans. This study used hydroclimatic variables including precipitation and temperature in Urmia Plain to find appropriate crops that needed the minimum irrigation water. In addition, the best time for planting each crop is determined. To find the proper crops for the region, the daily water, as required for each crop, was calculated based on climate condition, crop type, and crop growth stage. The results indicates that grape could be the best crop for the region. In addition, early planting (e.g. in spring) reduced the irrigation water needed due to more rain and soil moisture in spring than summer, which could provide crop water requirement. On the other hand, the increased temperature in spring could satisfy heat units required for the fully grown plants like barley.  

Land subsidence as a hydrogeomorphology event is currently occurring dangerously in many plains of the country due to uncontrolled groundwater extraction from water bearing layers, and accordingly monitoring and studying this phenomenon seems to be necessary. In this study, land subsidence rate of the Najafabad aquifer was determined through the Differential Radar Interferometry (DInSAR) processing of the ASAR and PALSAR radar data and the results were validated by comparying with the differential leveling and groundwater level drowdown data. Processing of the ASAR sensor data estimates the land subsidence in the Najafabad plain at an average annual subsidence rate of 6.7 cm and a total of 41 cm during 6 years period and processing of the PALSAR data suggests an annual rate of 7.7 cm and total subsidence of 30 cm during 4 years period. Most of the occured displacements are related to the Tiranchi, Koushk, Ghahderijan, Goldasht and Falavarjan cities. The simultaneous groundwater level data with acquisition date of the radar satellite images between 2002 and 2014 shows a drawdown ranging from 0.5 to 46.5 meters in the south and east to north of the Najafabad city consistent with the estimated land subsidence areas.The DInSAR processing of the PALSAR data has led to a more accurate results with higher spatial resolution. Results of the radar data processing can be employed for the hazard zonation directly utilized for management and planning of control and preventive measures.

Crop models evaluationin agriculture has been done by researchers. It helps them to determine the most appropriate crop model for the planning and simulation of crop response in different areas. Using can lead time and cost saving, helping to evaluate the effects of different situations on the crops yield, biomass and water use efficiency (WUE). Given the importance of the subject, this study was conducted for the accuracy and efficiency evaluation of AqauCrop and SWAP under three irrigation types (D: sprinkler irrigation with saline water, F: sprinkler irrigation with saline and fresh water, and S: surface irrigation) and five water qualities (S1: 2.5, S2: 3.2, S3: 3.9, S4: 4.6 and S5: 5.1 dS.m^-1). NRMSE results showed that the accuracy of AquaCrop for the simulation of yield, biomass and WUE was 0.07, 0.09 and 0.07, respectively. For SWAP, these were 0.12, 0.04 and 0.13, respectively. According to EF, AquaCrop results for above-mentioned parameters were 0.60, 0.90 and -4.4, and SWAP results were 0.74, 0.73 and -2.0, respectively. So, AquaCrop accuracy and efficiency were better than those of SWAP for the simulation of corn yield and biomass.

Several indices are used for drought identification and quantification. In this paper, the new Standardized Palmer Drought index (SPDI) was introduced and then the drought condition of Chaharmahal-Va-Bakhtiari Province was studied using this index. For this study, 11 synoptic, climatology, and evaporation meteorology stations were selected. Essential information in this investigation includes monthly temperature, monthly precipitation, and soil moisture measurement. To estimate SPDI, moisture departure, was first calculated on a monthly time scale. Then, converted to cumulative moisture departure values in different time scales including 3, 6, 9, 12, and 24 months. The best statistical distribution (GEV) was then fitted to cumulative departure. These values were then standardized to have the SPDI. The results showed that, as soil moisture affects SPDI estimation, it will be more valid for analyzing and monitoring drought conditions, especially for agricultural drought. Also, the results showed that 2000, 2001, and 2008 years were the driest time in this Province from 1988 to 2012. Moreover, drought frequency was found out in the western half of the Province more than in the other parts.

The contact angle is a numerical index of differentiation between hydrophilic and hydrophobic soils. The objectives of this research are: 1) assessing different methods such as capillary rise, the molarity of ethanol droplet, repellency index, and sessile drop, and 2) Determining the most efficient method in a typical soil with sandy loam texture. In this study, hydrophobic soil was hydrophobized artificially using stearic acid and according to the water drop penetration time classification method. Calculated contact angles of hydrophilic soil with capillary rise method, the molarity of ethanol droplet method, repellency index (two methods of calculation), and sessile drop method were 89.9, 75.41, (57.81), 56.28, and 58.91, respectively. Using the contact angle measuring device, the contact angle of five hydrophobic levels were 58.91, 104.92, 120.48, 129.96, and 173.07, respectively. According to the precession of the device where the operator is capable to control data and processes and there is no limitation in usage, therefore, the sessile drop method is the most suitable method to measure contact angle. The contact angle of the late method and water drop penetration data are positively correlated (R² = 0.975).

The upcoming climate change has become a serious concern for the human society. These changes, caused and aggravated by the industrial activities of the international community and the increase in the concentration of greenhouse gases in the atmosphere, are seen as a threat to the food security and environment. Temperature change and precipitation are studied in the form of different probabilistic scenarios in order to have an outlook for the future. The present study was conducted to address the effects of climate changes on temperature and precipitation in Qazvin plain in the form of five AOGCMs including Hadcm3, CSIRO-MK3, GFDL, CGCM3 and MICROC3.2, and 3 greenhouse gas emission scenarios of A1B, A2 and B1, based on different possible scenario combinations in the next 30 years, 2021-2050 and 2051-2080 (near and far future). On basis of the study results, all 4 target stations, on average, will have experienced a change between two ratios of 0.5 and 1.4 of  the observed precipitation period  by the end of 2050, and the mean temperature will have had a change  between -0.1 to 1.6 °C, relative to the observed period.  By the end of 2080,  the  precipitation will also have fluctuated between the two proportions of 0.5 and 1.7 times of the observed precipitation period and the mean temperature will touch an increase between 0.6 and 2.6 °C. Both SPI and SPEI indices suggest the increment in the number of dry periods in the near and far future. However, the total number of negative sequences differed considering the 3, 12 and 24-month intervals at the stations level. Given the SPEI index, as compared to the base period, the total negative sequences of drought and number of dry periods will increase at 3 stations of Avaj, Bagh-Kowsar and Shahid-rajaei-powerhouse and decrease at Qazvin station in the future; however, SPI gives different results, such that  for Bagh-Kowsar, there will be an increase in both total negative sequences of drought and number of dry periods, as  compared to the baseline period; three other stations will have more dry periods, specifically, but less total negative sequences. The results reported that the drought events would become severe, and the wet events would become extreme in the future.

Characteristics of most soils in arid and semi-arid regions affected by carbonates. The study aimed to determine the distribution of carbonates in the size components of some soils in Khuzestan province. Upward to the bottom of Karun, Karkheh, and Jarahi rivers were studied at depths of 0-50, 50-100, and 150-100 cm. The results showed that the average amount of carbonates in the soils of the Jarahi river basin (37%) was significantly different from the amount in the soils of the other two rivers (33%). Carbonates were observed in all soil size components but the maximum was present in the clay component. The highest regression relationship between soil particles was in the clay component (0.375). The highest percentage of particle reduction after carbonate removal was related to coarse silt particles (0.75). Therefore, the soil texture changed from clay in Jarahi, from clay and silty clay in Karun, and silty clay in Karkheh due to the removal of carbonates to sandy loam. There was no significant difference in the distribution of carbonates at different depths for river soils and all studied soils. The relatively uniform distribution of carbonates in the four components studied in these soils from the surface to the depth showed that the carbonates originated from the parent material, namely alluvial flood sediments of these rivers.

Water allocation needs to adhere to the principles of efficiency, equity, and sustainability, but, equity usually is less considered. Foumanat irrigation area with five command areas is one of the three areas of Sefidroud irrigation and drainage network that more than 90% of it is covered by paddy fields. Since water plays a key role in paddy fields, the lack of uniform distribution of water resources throughout the irrigation area during the rice cultivation period causes irrigation water scarcity and severe damage to some irrigation areas. In this study, the equity of groundwater withdrawal and the received surface water from Sefidroud irrigation and drainage canals according to the shared water resources among Foumanat’s command areas were evaluated using the Gini coefficient. Therefore, a water allocation optimization model was developed to maximize the equity in the allocation of groundwater and surface water of canals according to the minimum current economic benefit in the command areas. The results showed that in optimum conditions, the equity of groundwater and surface water resources allocation was increased by 46.3% and 43.7%, respectively. The evaluation of the optimal allocation of available water resources also showed that the amounts of groundwater withdrawal and the received surface water from canals are distributed equally among command areas.

To prevent demolishing bridge piles due to developing the scour hole under the foundation of these piles some solution has been proposed in the literature. One of the important approaches could be installing different geometric of roughness at the downstream and upstream piles sections. This causes the downward flows which are performing the main role in developing scour holes to be marginally decreased. The present study explores the effect of geometric roughness and also, continuity and un-continuity of roughness length on maximum scour holes around bridge pile. Results indicate that due to increasing the length of roughness the developed scour holes were formed by less scour hole depths. Furthermore, continuity of roughness increases the scour hole depths; however, un-continuity causes the height of scour holes to be developed by fewer values. Also, the comparison shows that the length of installed roughness in maximum value is decreasing the scour hole depth constitute 34 percent. Based on the non-linear regression technique an equation has been proposed to predict the maximum scour hole due to different conditions. Comparison between experimental and proposed values shows that the accuracy of the proposed equation has an acceptable error which has been calculated less than 11 percent.

The FAO Penman-Monteith is a baseline method to estimate reference evapotranspiration. In many cases, it is difficult to access all data, so replacing simpler models with ‎lower input data and appropriate accuracy is necessary. ‎ The purpose of this study is to investigate the capability of the experimental ‎models, gene expression programming, stepwise regression, and Bayesian network in estimating ‎reference evapotranspiration.‎ In this research, daily information of the Boroujerd synoptic station in the period of 1996 -2017 was used as model inputs. ‎Based on the correlation between input and output parameters, six input patterns were ‎determined for modeling. The results showed that the Kimberly-Penman model has the ‎best performance among the experimental models.‎ Gene expression programming with fourth pattern ‎‎and Default Model Operators (R² = 0.98 and RMSE = 0.9), Bayesian Network with sixth pattern (R²=0.91 and RMSE = 1.01), and stepwise regression with sixth pattern have the most accurate patterns at R² = 0.91 and RMSE = 0.9 in the ‎training stage.‎ Comparison of the performance of the three models showed that the gene expression ‎programming model was superior to the other two models with the Average Absolute Relative Error (AARE) of 0.12 and the Mean Ratio (MR) of 0.94.‎ The results showed that gene expression programming had an acceptable ability to estimate ‎reference evapotranspiration under the weather conditions of Boroujerd and could be introduced as a ‎suitable model.‎

In this study, spatial-temporal variation of dust deposition rate in the western and eastern half of Tehran and its climatic parameters affecting were studied. At 34 points in the city, dust samples were collected by glass traps from the roof, for twelve months, and the climatic data were obtained and analyzed from relevant organizations. The highest deposition rate is in the western half of the city and its total amount has varied from 54.52 to 121.21 g/m²/y. In both halves of the city, summer has the highest dust deposition rate and its central areas have the highest amount. There were significant positive correlations between dust deposition rate with temperature and medium wind speed, and there were significant negative correlations between dust deposition rate with rainfall and relative humidity in all months, which justifies the high dust deposition rate in the dry seasons of the year. The results of stepwise regression showed that rainfall was the most important factor affecting the dust deposition rate in both halves of the city. The city of Tehran has a special geographical location the presence of mountains like a barrier has prevented dust from leaving the city and the air inlet corridor of Tehran has faced problems due to the expansion of building construction and high-rise building. Other factors affecting the rate of dust deposition in this city, in addition to the distance from the main source of dust production, atmospheric parameters can be mentioned the existence of barren lands around the city, vegetation cover, construction operations, and traffic.

Delineation of gully erosion susceptible areas by using statistical models, as well as optimum usage of existing data and information with the least time and cost and more precision, is important. The main objective of this study is to determine the areas accuracy to gully erosion and susceptibility mapping by using data mining of the bivariate Dempster-Shafer, linear multivariate statistical methods and their integration in Semirom watershed, southern Isfahan province. First, the geographical location of a total of 156 randomly gullies were mapped using preliminary reports, satellite imagery interpretation and field survey. In the next step, 14 conditioning parameters of the gullies in the study area were selected including the topographic, geomorphometric, environmental, and hydrologic parameters using the regional environmental characteristics and the multicollinearity test for modeling. Then, the Dempster-Shafer statistical, linear regression, and ensembled methods were developed using 70% of the identified gullies and 14 effective parameters as dependent and independent variables, respectively. The remaining 30% of the gully distribution dataset were used for validation. The results of the multivariate regression model showed that land use, slope and distance to drainage network parameters have the most significant relation to gully occurrence. The gully erosion susceptibility maps were prepared by individual and ensemble methods and they were divided to 5 classes of very low to very high rate. The area under the curve (AUC) of the receiver operating characteristic (ROC) curve was used to validate gully erosion susceptibly maps. The verification results showed that the AUC of ensemble method (0.948) is higher than Dempster-Shafer (0.924) and Multivariate regression (0.864) methods. Also, the the seed core area index (SCAI) value of the ensembled model from very low to very high susceptible classes have a decreasing trend that indicating a proper separation of susceptible classes by this model.

In this study, the hydraulic characteristics of the flap gates are installed at the end of the trapezoidal channels were investigated by laboratory study. In the physical model, three trapezoidal channels and four gates with different weights were used (12 gates for three channels). Based on several experiments, equations for estimating of flow rate for each side slope (each channel) were developed using dimensional analysis. In this research, five forms of discharge-stage relationship were used to obtain relationships for each side slop to estimate flow rate, separately. The results show that none of the discharge-stage relationships forms as a single relationship for all flap gates in a certain channel are suitable for estimating discharge. But the first, second, and third forms of the discharge-stage relationship are very suitable for estimating the flow rate in a certain channel for a certain flap gate. In other words, for each gate with a specific weight, a separate (unique) relationship is obtained to estimate the flow rate in the form of the first to the third discharge-stage relationship in a certain channel. To estimate of flow rate by using the first form of the discharge-stage relationship, the maximum values of statistical parameters of RMSE, ME, and MARE, among all three channels, are 0.0001 m³/s, 0.00022 m³/s, and 0.22 percent, respectively. The values of all the above statistical parameters for the first, second, and third forms of the discharge-stage relationship are presented in the article.

Soil classification in a standard system is usually defined based on information obtained from properties and their variations in different map units. The aim of this study was to compare soil genesis and morphological characteristics in different landforms with WRB and Soil Taxonomy (ST) Systems. From nine studied profiles, six profiles were selected as representative profiles and dug in Colluvial fans, Piedmont plain, and Alluvial plain physiographic units, respectively. Then, the soils were classified according to the pattern of the two systems. Also, variation analysis of variance (ANOVA) and comparing means were used to quantify interested soil properties. The results of soil physio-chemical properties at different landform positions were significant based on analysis of variance of the effect of physiographic units and soil depth at the level of 1 %. Soil classification results based on WRB indicated that WRB were recognized four reference soil groups (RSG) included Regosols, Cambisols, Calcisols, and Gleysols at the first level of WRB classification in comparison of ST with recognizing two order Entisols and Inceptisols could separate more soils. The soils were located on the alluvial plain with a high groundwater level in the WRB due to the creation of restrictive conditions for root development in contrast to the ST called “Aquepts” in the suborder level but in a WRB is classified as the “Gleysols” RSG. On the other hand, ST, unlike WRB, used the Shallow criteria at the family level to describe the shallowness of soils and the limitations of root development. Generally, the efficiency of each system varies despite the differences in their structure and depending on the purpose of using them.