JWSS - Journal of Water and Soil Science

In recent decades, land use changes have been one of the most important environmental issues worldwide. This study was carried out to investigate and analyse land use changes in dust sources of south and south-east Ahwaz and surrounding lands using remote sensing technique. Firstly, based on the standard precipitation index (SPI), the years 1986, 2002 and 2016 were selected as years with near normal situation. In the next step, land use maps of the study area were extracted using a Landsat satellite images and supervised classification methods. MNDWI index was used to increase the accuracy of image classification. In order to evaluate the efficiency of each method, the overall accuracy and kappa coefficient were used. Finally, to investigate land use change a post-classification comparison method was employed. According to research findings, in the first period (1986-2002), the area of vegetation, wet land with vegetation and water bodies have increased by 419%, 219% and 40.7%, respectively, in contrast, the area of barren and poor range has reduced by 36.6%. One of the major causes of these changes is human factors such as population growth and climate variables such as proper amounts of precipitation. In the second period (2002-2016), the area of wet land with vegetation, water bodies and vegetation has been decreased by 94%, 49.3% and 46.7%, respectively; in contrast, barren and poor range land has been increased by 45.4%. Recent droughts increase the temperature and incorrect and non-principled management of water resources has been effective in reducing green cover and water bodies and increasing in bare land. The results show that, during the three decades, built-up land has been increased by 157%, while River bed has decreased by 28.8%. These results indicate a total degradation in the region due to climate change and human activities.

The Kor River in Fars province supplies an important part of water requirement in the Doroodzan dam basin and its surrounding area. In this study, the meteorological and hydrological droughts of this area were investigated in the last four decades. For this purpose, the temporal and spatial trend variability of the stream flow was investigated in monthly, seasonal, and annual time scales in the 6 selected stations. The trends of Standardized Precipitation Index SPI, as the drought index, in the 5 selected stations were also studied by the modified Mann-Kendall method. The results indicated that the trend in the stream flow was decreasing in all time scales. Significant downward trends were observed at 95% confidence level on monthly, annual and monthly time scales, especially in the warm months from May to September. These significant downward trends were located spatially in the stations located near the agriculture area, in the middle part of the basin. The significant upward trend existed only at the Doroodzan dam station, at the outlet in the area and in the warm months of the year. In the case of the SPI index, trends were  decreasing in all time scales and were  significant only at 2 stations in the long-term periods, 9, 12, and 18 months, at 95% confidence level. The results, therefore, indicated the occurrence of severe droughts (SPI<-2) during 1982-83 and 2007-8 periods.

This research tried to provide a sustainable solution for the allocation of water resources of Zayandehrood basin in a way ensuring minimal conflicts and tension between the stakeholders in use of the water resources, four main decision makers of the basis, comprising Regional Water Company, conflicts among Agricultural Jahad Organization, and Department of Environment of Isfahan Province and Chaharmahal and Bakhtiari Province, were reviewed and 128 possible cased  according to 7 scenarios were constructed and applied in the  GMCR model. According to the GMCR approach, 6 balanced sustainable scenarios in different climatic periods of the basin were presented. Finally, the results were generalized for choosing the best mode in the form of a scenario within the WEAP model; also, the results obtained from these scenarios were presented using the criteria of system performance assessment. On the basis of the findings, Scenario II was developed, comprising the application of new simultaneous management of demand and supply, restrictions in drawing water from water tables, new prioritization in stakeholder allocation and new water portion plans in the basin as the best scenario with 81.4% sustainability index.

Sediments are the sink where various contaminants accumulate; they are an inseparable component of ecosystems; among heavy metals are very important because of their harmful effects on the ecosystems and their long extremely long persistency. The present study was conducted to determine the concentration and contamination degree of heavy metals (Iron, Zinc, Copper, Manganese and Nickel) in the coastal sediments of Bushehr Port. In order to sampling sediments, a distance of 10 km was considered. Acid digestion method was used to prepare the samples for metal analysis. Also, the physical properties of the sediments were measured using the standard methods. The metal enrichment and contamination status in the sediments were determined using the contamination degree (Cd), the modified degree of contamination (mCd), the contamination factor (CF), the enrichment factor (EF), and the geoaccumulation index (Igeo). Based on the results, the distribution of heavy metals in sediments were obtained as Ni Fe> Mn > Zn > Cu >. In the present study, due to the distance between Asalouyeh and Bushehr port, a low nickel concentration was obtained. The results of Igeo and other indices showed that the surface sediments of the study were uncontaminated. Comparison of heavy metals in Bushehr Port sediments with sediment quality standards showed that the concentration of metals in this study was less than the standard levels. As a result, the Coastline of Bushehr port was not contaminatied with iron, zinc, copper, manganese, and nickel metals. The study, therefore, indicated that although there were slight changes in these indices, the combination of the indices could give us a comprehensive cognition of heavy metals risks in the surface sediments of the Bushehr Port.

One of the ways to increase water productivity in agriculture is the use of new irrigation systems; for the precise design of these systems, water quality assessment is needed. The purpose of this study was to study the groundwater quality of Khorramabad plain for the implementation of drip irrigation systems. The qualitative indices of EC, SAR, TDS, TH, Na and pH were related to the statistical years 2006-2012. In this research, the data were normalized first and it was determined that the data were abnormal; so, the logarithmic method was used for normalization. To evaluate the groundwater quality of the area, land use methods were used. Among different methods, the ordinary kriging interpolation method with the least root mean square error for all parameters was used. Quality zoning maps showed that in the north and southwest, EC and SAR concentrations were in poor condition in terms of qualitative classification. TDS had a concentration of more than 4000 milligramrels, and Na had a concentration of more than 15 milligrams / ltr. In these areas, TH with the concentration of more than 730 mg / l had the highest contamination; in the central area of the plain, there was a higher risk of carbonate sediments. LSI rates in the western regions were more than one, which included about 12% of the plain; there were restrictions on the implementation of droplet systems in these areas. The best quality for implementing these systems was located in the south-east of the plain, covering 19% of the plain. Finally, the integrated map of qualitative characteristics showed that the maximum concentration of qualitative characteristics was located in the northern, central and southern regions, which included 62.29% of the plain area.

Drought as a natural hazard is a gradual phenomenon, slowly affecting an area; it may last for many years and can have devastating effects on the natural environment and in human lives. Although drought forecasting plays an important role in the planning and management of water resource systems, the random nature of contributing factors contributing to the occurrence of and severity of droughts causes some difficulties in determination of the time when a drought begins or ends. The present research was planned to evaluate the capability of linear stochastic models, known as multiplicative Seasonal Autoregressive Integrated Moving Average (SARIMA) model, in the quantitative forecasting of drought in Isfahan province based on the Standardized Precipitation Index (SPI). To this end, the best SARIMA models were chosen for modelling the monthly rainfall data from 1990 to 2017 for every 10 synoptic stations in Isfahan province to forecast their monthly rainfall up to five years. The monthly time scale SPI values based on these predictions were used to assess the drought severity of different stations for the 2018- 2022 time period. The station results indicated a weak drought at the 2019- 2022 period for Isfahan, Kashan and Naeen, a severe drought in 2019 for Ardestan and Golpaygan, and a weak one in 2019 for the East of Isfahan, KabootarAbad and Shahreza stations. All other stations, except Golpayegan, Isfahan, Kashan and Naeen, faced a severe drought in 2018.

Soil pollution by heavy metals is a serious environmental problem that threatens the human health. The present study was carried out to investigate and detect the contamination of heavy metals of arsenic, copper, lead, zinc and iron due to human and natural activities in the sediment of lake bed and the surface soils of the eastern part of Urmia Province, West Azarbaijan Province. A total of 20 soil samples and surface deposition from the depths of 0 to 30 cm were collected randomly from the studied areas. After preparing the samples, extraction was carried out to determine the concentration of the heavy metals in the soil by using hydrochloric acid and nitric acid, and the total concentration of metals was measured using ICP-OES. The results of the calculation of the contamination factor showed that copper, iron, zinc and lead in the class of low and medium pollution and arsenic in 65.5% of the samples were very high in the class. The high concentrations of copper, lead and zinc contamination in the margin of the city and the contamination of arsenic in the lake bed were observed. The analysis of the contamination factor maps and contamination index with land use and geological map showed that copper, lead and zinc were mostly affected by human activities and arsenic influenced by the maternal materials in the region.

The purpose of this study was to analyze the temporal variations of dust phenomenon and its relationship with the climatic elements in Yazd city, located near one of the critical centers of dust production in the center of Iran. For this purpose, the Dust Storm Index was first calculated. After the standardization of precipitation, temperature, maximum wind speed, average wind speed, relative humidity and, dust storm index, the co-linearity effect between variables was calculated by using inflation variance factor. Then, several regression models were prepared based on the optimal Ridge parameter. The performance of the models was evaluated based on the determination coefficient, F value and Root Mean Square Error. Finally, by using the most accurate model, the impact of climate parameters on the dust events changes was determined. The results showed that the incidence of dust events in the spring was more than the rest of the year. Based on the optimal model (Model 12), it was found that the main factor influencing the dust storm index variations in different seasons was the surface winds speed. It was also shown that 39%, 25%, 46% and 31% of dust storm index changes in winter, spring, summer, and autumn were due to the interaction of the five climatic parameters studied in this study.

The present study aimed to evaluate the growth and water use efficiencies of eight late-maturing corn hybrids in comparison to the common use of KSC704 and Maxima-FAO530 under different water-nitrogen management systems. Two irrigation regimes (based on 50% soil-water depletion as the normal irrigation and, on average. 16% less than normal as the deficit irrigation) and two nitrogen (N) application managements (3 and 16 split-application of 150 kg N from Urea, 45% N) were induced using the split-split plot experiment based on a completely randomized block design with four replications at Research Field of Isfahan University of Technology on 2017. The results showed that yield, forage and leaf area index were significantly (P<0.01) affected by the interaction of three studied factors (Irrigation × Nitrogen × Corn hybrid). For different corn hybrids, more water use efficiencies were achieved by deficit-irrigation regime and 16- split-applyication of N; in this regard, the SC719 hybrid had the highest value of 3.45 kg m^-3. Generally, the performances of the studied late maturing corn hybrids were higher than those of the control hybrids of SC704 and SC530 at this planting date, which could be improved by using the deficit-irrigation regime and more split-application of the N fertilizer.

The occurrence of wind erosion and the spread of dust particles can be regarded as one of the most important and threatening environmental factors. Climate change and the frequency of droughts have played an important role in exacerbating or weakening these events. The primary objective of the present study was to investigate the trend of changes in four important climatic elements (precipitation, temperature, wind speed and relative humidity) and dust storm index (DSI) in Qazvin city using the Mann-Kendall pre-whitened test and to determine the relationship between them based on the multiple linear regression method. Assessment of the meteorological drought status based on two standardized precipitation index and standardized precipitation, as well as the evapotranspiration index and analysis of their effect on activity level of dust events, was the other objective of this study in the study area. For this purpose, after preparing and processing the climatic data and calculating the dust storm index, the trend of changes and the relationship between climatic parameters and dust events were investigated. The results showed that the changes of trend in the annual precipitation and relative humidity in Qazvin city were increasing, while the trend of annual changes in the wind speed and the mean air temperature was a decreasing one. Investigation of the monthly changes in the dust events also showed that there was a sharp decrease in the occurrence of wind erosion and the spread of domestic dust particles only in July. On a seasonal scale, with the exception of winter that has been reported without trends, in other seasons, the intensity of these events was significantly reduced. The effect of the meteorological drought on wind erosion was estimated to be 11% at the confidence level of 99%. In general, these findings indicate a decreasing trend of land degradation and desertification caused by wind erosion in Qazvin.

Optimal use of water resources seem to be necessary due to climate change and the recent drought conditions. One of the most important and effective management strategies is increasing water productivity in agriculture. Irrigation method and the use of different levels of nitrogen fertilizer are the effective factors in increasing the water productivity. Therefore, this study was conducted to investigate the effect of the irrigation method and nitrogen fertilizer on the harvest index and water productivity of two wheat cultivars with 36 treatments as a split-split plot based on a completely randomized design with three replications in the research farm of Natural Resources and Agricultural Research Center of Kashmar, during the 2018-2019 time period. The treatments were two irrigation methods including end blocked border and drip irrigation (tape) as  the main plots, three levels of the nitrogen fertilizer from urea source including 0, 50 and 100 kg/ha as the  sub plots and two cultivars of wheat including Pishgam and Sirvan as the sub-sub plots. The results showed that by changing the border irrigation method to the drip irrigation (tape) method, the harvest index and water productivity were increasesignificantly. The results also showed that grain yield and its components, including harvest index and water productivity, had no significant difference in 50 and 100 kg/ha nitrogen levels. On the other hand, grain yield and its components, harvest index and water productivity, were significantly higher in the Sirvan cultivar rather than the Pishgam one (P<0.01). According to the results obtained from this study, the drip irrigation method, 50 kg/ha nitrogen level and Sirvan cultivar could be recommended for the study region. 

Identification and investigation of changes in the area under cultivation of various crops seem to be essential for the management supply of crop production. In this study, r to identify and investigate change of the area under cultivation in major crop Hoseynabade Mishmast region in Qom province, we used the time series images of OLI and ETM sensors of landsat 8 and 7satellites, according to the crop calendar of this region. By using the vegetation index (NDVI) in the decision tree algorithm, the thresholds of this index were adjusted according to the major crops of this region; then a map of the cultivation pattern of the crop of this region was prepared. In order to evaluate the results, the statistics of the provinces agricultural jihad were used during 2005, 2009, 2014 and 2019 crop years. The results showed that by using the threshold of NDVI index, crops in this region in 2005 included wheat and barley and alfalfa, and their areas had an error of 17/1 and 6/1 percent in comparison with the statistics of agricultural Jihad, respectively; in 2009, wheat and barley, alfalfa and corn had an error of 0/5, 9/6 and 0/1 percent. Also, in 2014, wheat and barley, alfalfa, corn and sophie crops had an error equal to 4/9, 0.4, 11/4 and 2/4 percent, and the same crops in 2019 had an error 0/04, 11/6, 1/4 and 17/5 percent; that error was not significant. According to the results, the appropriate efficiency NDVI index in estimating crop cultivation area was determined by their phenology. Also, in 2009 and 2014, corn and sophie crops were added to the regions crops, and the area under crops cultivation in 2019 was increased, as compared to 2014.

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.

Snow cover is one of the important climatic elements based on which climate change may have a special effect. In general, climate change may be reflected in different climatic elements. Therefore, it is very important to study and measure changes in snow level as one of the important sources of water supply. Ardebil and Sarein cities are located at 48° 18׳ east longitude and 38° 15׳ north latitude. In this study, Sentinel-2 optical satellite was used to monitor the snow cover surface in 2018, and NDVI, S3, NWDI, NDSI, Cloud mask indices were applied to detect snow-covered surfaces using ArcGIS and Snap software. Next, to validate the snow maps extracted from the images, it was compared with the snow data in terrestrial stations using linear regression in MATLAB software and to evaluate the accuracy of the model statistical indices including RMSE, MSE, BIAS, CORR were used. The present study showed that according to Ardabil city climatic conditions, maximum-snow covered area in January with an area of 356.52 km2 and minimum snow-covered area in March with an area of 96.10 km2. The highest snow cover is observed in the high slope areas in the western slopes (Sabalan Mountain Heights) and the lowest snow cover is observed in the lower eastern slopes. The results of linear regression with generalization coefficient are 85% and the results of statistical indices of error are equal to MSE: 0.086, BASAS: 0.165, CORR: 0.924, and RMSE: 0.03. Correlation relationships between terrestrial data and estimated snow maps showed a high degree of correlation. This result is statistically significant at the 99% level. The use of optical images in estimating snow levels is very cost-effective due to the size of the areas and the high cost of installing snowmobiles. The results obtained in the present study indicated that traditional radar images with high spatial resolution and good correlation with terrestrial data can be a good alternative to snowmobiling ground stations at high altitudes or in passable areas.

Drought is one of the most complex natural disasters due to its slow onset and long-term impact. Today, the use of remote sensing techniques and satellite imagery has been considered a useful tool for monitoring agricultural drought. The objective of the present study was to evaluate spatial and temporal monitoring of agricultural drought in the lake Urmia catchment area with the ETDI drought index which is calculated from Nova satellite images based on actual evapotranspiration from the SEBS algorithm and compared with the ground index SPI. For this purpose, 248 AVHRR sensor images and NOAA satellites during the statistical period of 1998-2000 and 17 meteorological stations with a statistical period of 30 years were used to calculate the indicators. To determine agricultural lands, six thousand points were marked for different uses and their actual evapotranspiration was calculated using the SEBS algorithm. The results showed that with the onset of the drought period in 1998, the ETDI index indicated 9.4% in weak drought conditions in May and 90.6% in normal conditions. Over time, in June of 1998, the situation was different with 95% in a weak drought situation and 5% in a normal situation for the city of Tabriz. In July, the entire catchment area experiences a slight drought. Then, in August, 84% of the basin is in normal condition and 16% in Tabriz and Urmia are declared weak drought. It was also founded that the ETDI drought index due to the combination of visible and infrared bands and its combination with terrestrial data has a physical meaning and has high certainty and predicts drought faster and more accurately.