Journal of Water and Soil Science

Study of Groundwater Table Variations and Drought Monitoring Using GRI Index in Shiraz Plain (Maharloo-Bakhtegan Watershed)

I. Saleh

Groundwater resources are affected by long-term drought conditions and have received less attention than other issues. The current research was carried out to investigate and zone the quantitative fluctuations of groundwater as well as the temporal analysis of groundwater drought using GRI in the study area of Shiraz in the Maharloo-Bakhtegan watershed. The zoning of groundwater table variations was done in the ArcGIS environment, and a representative hydrograph of the aquifer was prepared using 15-year data (2003-2018) of groundwater resources divided into three five-year periods. Also, the drought of the groundwater resources of the studied plain was investigated using the GRI index. According to the results, the highest level of the groundwater table is related to the northwestern area of the plain by 1810.1 m in October 2007, and the lowest water table was observed in the southern study area with the amount of 1423.6 m in October 2017. Also, the results showed that the groundwater table faced a drop of 6 m and an average annual drop of 0.5 m during the studied 15 years. The volume changes of the reservoir also indicated that, in addition to consuming the entire renewable reserve, a large part of the fixed reserve has also been exploited in the past years. The descending trend of GRI and its intensification in the last years of the studied period is one of the most important results of this research, which occurred due to population growth and increasing cultivated area, a decrease in precipitation, and climate change.

Wheat Production Simulation Using Sentinel 2 Images and Machine Learning Techniques

H. Ramezani Etedali

change, accurately predicting wheat production is essential for developing precision agriculture. Remote sensing enables the indirect prediction of crop production before harvest. This research investigates the application of the random forest method and support vector regression for simulating wheat production across ten selected farms in Qazvin Plain from 2019 to 2020, employing NDVI, MSAVI, and EVI vegetation indices. Sentinel 2 satellite data was utilized for the vegetation indices. Production data for the ten wheat fields was obtained from the Agricultural Jihad Organization of Qazvin Province. Evaluation of support vector regression and random forest to assess both the observed and simulated wheat production data was conducted using R2, MBE, RMSE, and MAE statistics. To explore the simulation of wheat production using vegetation indices, seven methods were defined: methods 1 to 3 examine each index separately; methods 4 to 6 focus on binary combinations of the indices; and method 7 considers the combined effects of all three indices. The support vector regression model provided good estimates of wheat production in all methods, except methods one and four, in the test phase, with a coefficient of determination of more than 0.98 and a low RMSE. The random forest model showed significant results in all methods except methods two and six during the test phase, achieving a 95% probability (P-value=0.00) with a coefficient of determination greater than 0.8. Overall, this research highlights the importance and potential of machine learning techniques for timely crop production prediction as a strong foundation for regional food security.

Estimation of Water Stress Multivariable Index (Case Study: Kashan City)

M. Khoshoei

The issue of water scarcity or the limited availability of water resources, including concepts such as water stress, water shortage, and water crisis, is investigated in this study. Water stress refers to problems related to access to freshwater resources, particularly due to the excessive withdrawal of surface and groundwater. A water crisis describes a situation where the available clean and safe drinking water in a specific region is insufficient to meet demand. Factors like drought, reduced rainfall, and pollution can exacerbate water stress. Water shortage arises from reasons such as the inability to meet demand, economic competition over water quality and quantity, conflicts among users, the irreversible depletion of groundwater resources, and negative environmental impacts. This study provides an index to assess water stress for spatial analysis in the study area and analyzes relevant data by collecting information from various sources. This index utilizes both static and dynamic parameters to estimate drought and better depict water stress conditions. Static parameters include land use, slope, and soil type. Dynamic parameters include precipitation, temperature, and groundwater level. Kashan County was selected as the case study due to the continuous reduction in water resources. The results showed that in the water years 2005, 2014, 2020, and 2021, Kashan experienced the highest level of water stress, while in the water years 2002, 2004, 2010, 2012, 2013, and 2015, it experienced the lowest level of water stress.

Assessment of the Water Footprint of Large Industries in Zayandeh-Rud Watershed

N. Mirghaffari

The water footprint is an analytical tool that offers a better and more comprehensive view of how consumers or producers engage with freshwater consumption. Given the water crisis in the country, particularly in Isfahan Province, this study aims to estimate and compare the direct and indirect water footprints of several large industries, including Mobarakeh Steel, Iron Smelting, Refinery, and Power Plant, located in the Zayandeh River Basin. After identifying the desired objectives and study areas, as well as confirming the availability of the required data, information was gathered from the selected industries. Two methods were then utilized to aggregate the entire chain and the sum of steps to calculate the water footprint in the researched industries. According to the calculations, the direct and indirect water footprint in the iron smelting industry amounts to 196.9 cubic meters per ton of steel annually, of which 4.026 cubic meters is attributed to direct consumption and 17.5 cubic meters to indirect consumption. In a refinery, 18.80 liters of water are consumed directly and indirectly to produce one barrel of product (gasoline or diesel). Additionally, the direct and indirect water footprint of the Islamabad power plant is 1,198,320 cubic meters per terajoule, equating to 4.31 liters per kilowatt hour. The results of this study indicate that the indirect water footprint in the analyzed industries is equal to or exceeds direct water consumption, with both being equally significant. Finally, it is important to note that the results of this study can support decision-makers and policymakers in the industry, including those in the iron and steel, refinery, and power plant sectors, in managing their water footprint.

Analytical Examination of Nutritional Value of Drinking Water Using the Drinking Water Nutritional Quality Index Case Study: Drinking Water of Shiraz City

M. Noshadi

In this research, drinking water quality was investigated using acceptability, health, and nutrition-based indicators from 2010 to 2022 in Shiraz City (Fars province). Magnesium, fluoride, and calcium play a significant role in the contribution of drinking water in Shiraz City to the intake of dietary minerals. The acceptability water quality index (AWQI), health-based water quality index (HWQI), and drinking water quality index (DWQI) rankings in Shiraz City are excellent, but the average drinking water nutritional quality index (DWNQI) of Shiraz City is 77.52 ± 5.47, which falls within the good ranking. Therefore, while the conventional water quality indices (AWQI, HWQI, and DWQI) are excellent, the DWNQI index does not achieve an excellent rating, due to the inclusion of the nutritional value of water in the DWNQI index. In general, the trend of AWQI, HWQI, DWQI, and DWNQI over thirteen years in Shiraz City shows that the conventional drinking water quality indices (AWQI, HWQI, and DWQI) do not provide an accurate picture of the assessment of drinking water quality in many cases, as they do not consider the nutritional role of water. For this reason, water is sometimes treated more than necessary. Therefore, it is essential to revise the interpretation of drinking water quality using the DWNQI index to gain a comprehensive picture of drinking water quality.

An Assessment of Drought Severity Using Drought Indices based on Potential Evapotranspiration-Based and the TOPSIS Multi-Criteria Decision-Making Model at Selected Stations within the Zayandeh-Rud River Basin

S. Eslamian

Drought represents one of the most critical natural disasters, exerting profound impacts on agriculture, society, the economy, and water resources. Various indices are used to monitor drought and its effects. This study aims to monitor drought in the Zayandeh-Rud Basin using the Standardized Precipitation Index (SPI), the Standardized Precipitation-Evapotranspiration Index (SPEI), the Evaporative Demand Drought Index (EDDI), the Palmer Drought Severity Index (PDSI), and the Reconnaissance Drought Index (RDI). All these indices are based on potential evapotranspiration, incorporating parameters such as precipitation, temperature, relative humidity, wind speed, and sunshine duration. These five indices were calculated and evaluated during the statistical period of 1993–2023 for meteorological stations in Isfahan, East Isfahan, Kabootarabad, Daran, Shahreza, Najafabad, and Mobarakeh. After calculating the indices and using spatial zoning maps, the studied stations were compared in terms of these indices. The continuity of dry and wet periods, as well as the intensity of droughts and wet spells, was analyzed. Subsequently, drought intensities during different years in these stations were ranked using the TOPSIS model based on factors such as precipitation, potential evapotranspiration, and station elevation. The results showed that in stations with a dry climate (such as Isfahan, East Isfahan, and Shahreza), drought occurrences (as indicated by higher rankings) have been consecutive over multiple years. Comparing the performance of the indices in the studied stations using spatial zoning maps revealed that the intensity of droughts and wet spells in regions with dry and semi-dry climates was not very significant. However, in areas with humid climates, the fluctuations in drought and wet spell intensities were quite substantial. The findings indicate that the PDSI and EDDI indices are more suitable for evaluating drought in dry climates.

Environmental Assessment of Agricultural Activities on the Geochemistry of Surface Soils in the Pistachio Orchards of Southern Mehriz

J. Ghaneiardakani

This study investigates the impact of agricultural activities on the soils of southern Mehriz by analyzing their geochemical composition and comparing the physicochemical properties of pistachio orchard soils (agricultural soils) with those of undisturbed natural soils. The results indicate that agricultural practices have led to an increase in Total Organic Carbon (TOC), averaging 1.5%, and a reduction in soil acidity. Additionally, phosphorus concentrations have risen in agricultural soils. These soils also exhibit enrichment in elements such as cadmium (Cd), antimony (Sb), chromium (Cr), nickel (Ni), lead (Pb), scandium (Sc), and rare earth elements (REE) compared to natural soils, with a more homogenized REE distribution pattern. Although the concentrations of these trace elements remain within national environmental standards and below critical thresholds, the study highlights a significant increase in the bioavailability of heavy metals due to agricultural activity. This finding underscores a potential environmental risk if such changes are not properly managed in the future.

Evaluation of the Effect of Soil Fertility Management Scenarios on the Amount of Available Nitrogen, Phosphorus, and Potassium in Soil in Six Consecutive Cultivations

S.A. Ghaffari Nejad

This study was conducted to evaluate soil fertility management scenarios including separate use of chemical and organic fertilizers (animal manure and municipal waste compost) and their integrated application on changes in the amount of available nitrogen, phosphorus, and potassium in the soil from November 2017 for four years in six consecutive crops at the Agricultural Research Station of the Soil and Water Research Institute. The results showed a depletion of 14 and 44% of soil available nitrogen and phosphorus, and no depletion of available potassium in the treatment without fertilizer in six consecutive cultivations. Annual consumption of 20 t ha^-1 of municipal waste compost and 75% of the recommended nitrogen showed the highest amount of soil-available nitrogen. Unlike phosphorus, the amount of soil available nitrogen in municipal waste compost treatments was significantly higher than in cattle manure. The highest available soil phosphorus was in the treatment with 10 t ha^-1 of cattle manure before each crop, and the average available phosphorus in six consecutive cultivations was significantly higher than in the other treatments. The use of 10 t ha^-1 of cattle manure and municipal waste compost before each crop resulted in the highest accumulation of potassium in the soil, respectively. The available soil potassium in cattle manure treatments was significantly higher than in municipal waste compost. The results of this experiment indicated the importance of using fertilizers containing nitrogen, phosphorus, and potassium in maintaining soil fertility stability in the long term.

Laboratory and Numerical Study of Hydraulic Loss and Discharge Coefficient in Rectangular Labyrinth and Piano Key Weirs

M. Heidarnejad

the impact of hydraulic loss on the performance of weirs should not be overlooked. In this study, a laboratory flume measuring 8 meters in length, 0.6 meters in width, and 0.6 meters in height was used to investigate the hydraulic loss of the weirs and their discharge coefficients. The weirs used in this research were of the labyrinth type, featuring both curved and linear designs. Dimensional analysis using the Buckingham method indicated that the discharge coefficient (Cd) relies on parameters such as the hydraulic head ratio (Ht/P), weir shape factor (Sf), hydraulic loss ratio (Hf/P), and Froude number (Fr). The results demonstrated that an increase in hydraulic head leads to a decrease in the discharge coefficient of the weirs. Furthermore, the intensity of flow blade interference over the weirs gradually increases the hydraulic loss with a rising hydraulic head. Hydraulic loss increases up to a certain level of hydraulic head before beginning to decline. Therefore, it can be stated that the hydraulic loss curve for weirs like ARCL exhibits a sinusoidal trend. At a hydraulic head ratio of 0.4, the ARCL weir experiences 227% more hydraulic loss compared to the APKW weir. At a hydraulic head ratio of 0.6, the RCL weir shows 200% more hydraulic loss than the PKW weir. The trend of hydraulic loss variation with increasing Froude numbers for ARCL and RCL weirs is also sinusoidal. The ARCL weir shows the highest hydraulic loss with increasing Froude number compared to the other weirs. All weirs modeled using FLOW-3D software showed values (Cd and Hf/P) that exceeded those from physical modeling, which is significant in terms of safety factors. Moreover, the error rate in numerical modeling varied based on different parameters and conditions, averaging between 10% and 30%. In some cases, labyrinth weirs exhibited higher error rates compared to piano key weirs.

Spatial Analysis and Identification of Erosion and Sediment Hot-Spots Along Zagros Forest Roads

S. Yousefi

In the present study, the Road Sediment Delivery Model (SEDMODL) and Geographic Information System (GIS) were utilized to estimate the average annual sedimentation caused by the forest road network in the oak forests in the west of Iran, Chaharmahal and Bakhtiari Provinces (Nazi forest road with a length of 5171 meters). Sedimentation from the study forest road network was estimated based on three basic factors in the model. Also, 30 erosion benchmarks were installed to measure the erosion and sedimentation rate at different distances from the road and in different parts of the study road and changes were measured during a year. The results showed that the average soil erosion at different distances from the Nazi road based on erosion benchmarks is 5.7 mm per year. In addition, the estimated erosion and sedimentation rate of the entire study road network based on the SEDMODL model is 2875 and 570 tons per year per kilometer, respectively. Model evaluation using erosion benchmarks showed that SEDMODL is a suitable model for estimating soil erosion on forest roads in the west of Iran (R²=0.78 and RMSE=0.73). It should be noted that statistical analysis of erosion hot-spot analysis showed that 39 percent of forest roads in Nazi showed very high erosion. Based on the results of the present study, it is suggested that conservative, protective, and road maintenance measures in areas with high erosion risk should be prioritized by decision-makers.

Dyeing Wastewater Treatment Using a Batch Electrocoagulation System and Investigating the Effect of Retention Time and Electrode Distance on Removal Efficiency

M. Heidarpour

The growing concern for environmental protection and increasing demand for green approaches to address environmental problems have prompted researchers to explore a sustainable and reliable method for treating dyeing wastewater. One of the sustainable and reliable methods is the electrocoagulation process. In this study, a batch electrocoagulation reactor was designed to evaluate the efficiency of this process in treating dyeing wastewater. The effects of two parameters, electrode distance and retention time, on pollutant removal efficiency were investigated. Electrode distances of 2, 5, and 7 cm were tested, and retention times of 10, 15, 20, 25, and 30 minutes were examined. Results indicated that the optimal electrode distance was 5 cm and the optimal retention time was 20 minutes. Under these conditions, the removal efficiency of BOD, COD, TSS, color, and turbidity reached 83%, 85%, 98%, 98%, and 93%, respectively. The results of this research demonstrate the significant potential of the electrocoagulation system for treating dyeing wastewater.

The Role of Soil Water Solutes Type on Changes in Evaporation Intensity from sandy and clayey soils

M.R. Shoaibi Nobariyan

The objective of this study is to investigate the effects of solutes and water quality on evaporation amount and rate in two sandy and clayey soils. Soil samples containing aggregates and sand particles with diameters ranging from 0.5 to 1 millimeter were collected. Six columns were prepared during the experiment; three columns were filled with sandy soil and three with aggregated soil, each measuring 60 cm in height and 15.5 cm in inner diameter. One reference column was filled with distilled water. A saturated calcium sulfate solution was added to two columns, a 0.01 molar calcium chloride solution was added to two other columns, and distilled water was added to the remaining two. The amount of water lost through evaporation was recorded every 8 to 12 hours by weighing the columns. After approximately 130 days, the columns were sectioned, allowing for the establishment of moisture and solute concentration profiles for each soil column. The results indicated that the first and second stages of evaporation were distinguishable in sandy soil, whereas in clayey soil (aggregated soil), only the first stage of evaporation occurred due to the gradual transfer of water and the continuous hydraulic connection from the surface to the water table. The presence and type of solutes affected the evaporation rate and moisture profile, reducing evaporation and increasing water retention in deeper soil layers. Hydraulic connectivity (calcium sulfate > calcium chloride > distilled water) and the resulting capillary rise of and supply of evaporated water from higher layers caused a greater evaporation rate in the calcium sulfate compared to the calcium chloride and distilled water treatments in both soil types. Additionally, the formation of a salt crust on the soil surface due to solutes disrupted the hydraulic connection with the surface, resulting in decreased evaporation rates and cumulative evaporation.