مجله تحقیقات آب و خاک ایران
سال پنجاهم شماره 9 (پیاپی 47، بهمن 1398)

Various wastewaters such as household, industrial and agricultural wastes are entered along the Dez River from different locations. Regarding the water scarcity crisis, a comprehensive study on quantitative and qualitative pollution and using management tools such as mathematical and computer models is needed to predict water quality of this river and to prevent its further pollution. In this research, the qualitative QUAL2K model was used for simulation of NO3-, PO4-3 parameters at seven stations; Chamgolak, Dolat park, third bridge, new bridge, floating bridge, fifth bridge and Gavmishabad. The calibration and prediction of the model was done using quality parameters of the river and other information obtained from the field studies. Also, root mean absolute error (MAE) and coefficient variation (CV) were used to validate the model by comparing the observation and prediction data. The results of the model represent the real conditions of the river to an acceptable level, which indicates the ability of the Qual2kw model for simulation of the quality parameters. Most of the river pollution is caused by urban sewage. According to the results, PO4-3 parameter during the studied period is considered to be threaten to aquatic life. But, according to water quality standard for agricultural use, there is no limitation for Dez River. The low discharge at the river downstream and the high loading of pollutants have increased the concentration of water quality parameters. According to the results of the EF, MAE and CV parameters, the model had the best fit for water nitrate.

Screens are lattice plates with certain porosity arranged vertically in the supercritical flow inducing energy dissipation and hydraulic jump stabilization. In this study, energy dissipation due to Hydraulic jump and Screens are investigated experimentally. The main variables of the study are: (i) the Froude number of supercritical flow (FrA) in the 3.5-8 range; (ii) five samples of bed grains with a median diameter of 4.1-24 mm; (iii) screen with 40% and 50% porosities. The results from the study clarified change energy dissipation pit against supercritical Froude number, the participation of Screen and hydraulic jump in energy dissipation and the effect of porosity on energy dissipation. Also, to calculate the energy dissipation in the downstream of the Screen, some relationships have been presented and the results have been compared with previous studies. The results showed that the Froude number (FrA) of supercritical flow have a great effect on energy depreciation. Also, the effect of dimensionless grain sizes (d50) and maximum scour depth (Ds) is negligible on energy depreciation.

Empirical and theoretical methods (energy balance) are widely used to calculate the Crop Water Stress Index (CWSI) and irrigation scheduling to describe crop water status. In this study, irrigation scheduling was performed at the research farm of College of Agriculture, Urmia University, using a manual infrared thermometer and the empirical method of Idso et al. (1981) for the black gram under different irrigation regimes using drip irrigation in 2017. The experimental design was carried out in a randomized complete block design with three levels of irrigation I1, I2 and I3 which were 50, 75 and 100 percent water requirement in three replications, respectively. Using the baselines obtained for each treatment, the average CWSI values during the growth season of black gram for I1, I2 and I3 treatments were calculated to be 0.37, 0.23 and 0.15 respectively. The relationship between CWSI and total irrigation depth (mm) was determined as CWSI = -0.0008 (I) + 0.58, and the relationship between black gram grain yield (ton/hec) and CWSI was determined as Yield = -1.8237 (CWSI) + 2.1435 which their correlation coefficients (R2) were 0.98 and 0.99 respectively, which shows the high accuracy of regression models. In general, if the amount of water decreases with stress during the plant growth, the CWSI value increases, and as a result of increasing CWSI, the crop grain yield decreases. Finally, the no stress treatment (I3) with CWSI=0.15 was the basis for irrigation scheduling and then some relationships were established for determining the irrigation time using CWSI in Urmia climate for four stages of black gram growth; flowral induction-flowering, pod formation, seed and pod filling, and physiological maturity as (Tc  ̶ Ta)C = 1.9498  ̶ 0.1579(AVPD), (Tc  ̶ Ta)C = 4.4395 ̶ 0.1585(AVPD), (Tc  ̶ Ta)C = 2.4676  ̶ 0.0578(AVPD) and (Tc  ̶ Ta)C = 5.7532  ̶  0.1462(AVPD), respectively.

Groundwater resources have been one of the main freshwater suppliers in arid and semi-arid areas of Iran. Due to population congestion in coastal areas, these resources have been threatened by both natural events and human activities. The present study considers the simulation of Lahijan-Chaboksar coastal aquifer in Guilan province, Iran. Hence, a three-dimensional, heterogeneous and anisotropic numerical model has been developed using SUTRA. The model has been applied after the calibration and verification procedures. Different possible future scenarios including the water level reduction in land boundary with/without increment net exploitation of aquifer, desalination plant wastewater disposal into aquifer/sea and their effects have been simulated and evaluated. Results showed that 10 m reduction of water level in land boundary, led to about 6 m reduction of average groundwater level within 30 years but it has no remarkable effect on aquifer’s quality. At the same period, 10 m reduction of water level in dry border beside the increase of net exploitation of aquifer (5 times), led to 13 m reduction of average groundwater level and the quality of groundwater decreases. However, injecting the wastewater of desalination plant into the aquifer increases the groundwater level about 1.4 m, but the quality of groundwater extremely decreases, while discharge to the sea has no effect on the aquifer groundwater level and the quality.

In order to increase the efficiency of surface irrigation systems, it is necessary to estimate the coefficients of infiltration equations with high precision. Inverse modeling is a precise method for estimating the coefficients of infiltration equations. In this research in the first step, the performance of different infiltration equations including NRCS intake families, Kostiakov, modified Kostiakov, modified Kostiakov Branch Functions, Time-Rated Intake Family and Characteristic time were evaluated and compared. Then the best infiltration equation was determined so that it could estimate the advance, recession and runoff phases with the least error. By comparing different infiltration equations, the modified Kostiakov method with a mean percentage error of 2.14, 2.99 and 2.95 was determined as the best-performance infiltration equation in advance, recession and runoff phases, respectively. In the second step, based on the optimal infiltration equation (modified Kostiakov), three commonly used software for inverse estimation of infiltration equation parameters including: WinSRFR, IPARM and SIPAR-ID were compared using field data of four furrow irrigation under corn cultivation located at the research farm of agriculture and natural resources campus of university of Tehran in 2014. The results showed that the IPARM model with mean percentage errors of  2.40, 5.87, and 2.11, respectively, in advance, recession and runoff phases had a similar performance with the WinSRFR software, but it estimated the recession phase with an error of almost two times as compared to WinSRFR. The SIPAR-ID model in estimating the infiltration equation coefficients had poor performance with the highest volatility in the coefficients values.

This study was performed to investigate the effect of salinity stress and evaporative demand on water uptake by maize (Zea Mays L.). For two seasons, greenhouse experiments were conducted in pots in a completely randomized design with 4 replicates in 2017. Water uptake by maize was measured daily under constant matric suction of 100 cm at different salinity levels (0, 1.7, 3.36, 6.33 and 8.35 dS/m). The electrical conductivity in pots was kept constant after the treatment initiations. The salinity threshold level was determined to be 0.52 for spring season and 1.48 dS/m for autumn season based on salinity of irrigation water which implies more sensivity of maize to salinity stress under high evaporative demand as compared to low evaporative demand conditions. The imposed salinity stress significantly affected water uptake and yield in both spring and autumn seasons. The estimated yield and water uptake values using reduction functions indicated that the exponential model of van Genuchten-Hoffman had more accuracy than the linear model of Maas-Hoffman for yield, while the accuracy of linear model was more than the exponential model for water uptake, especially in autumn season. It is concluded that the plant response to salinity stress is not the same under different evaporative demand conditions.

The purpose of this study was to investigate the effect of irrigation with urban treated wastewater on yield, yield components and water use efficiency of maize (Single cultivar 704) at the research field of Aburaihan Campus, University of Tehran in Pakdasht during the year of 2017. The experiment was carried out as split plots and based on the randomized completely block design with main factor (type of irrigation water) and sub factor (three levels of water requirement) with three replications. Type of Irrigation treatments included well water and treated wastewater that were used in three levels of water requirement including 100 (D1), 75 (D2) and 55 (D3) percent of maize water requirement. The results showed that the type of applied water caused a significant difference in dry matter, so that the highest yield (2090.18 kg/ha) was obtained in wastewater treatment and the lowest yield (17231/15 kg/ha) was obtained in well water treatment. In terms of different amounts of water, the highest water use efficiency based on dry matter (3.52 kg/m3) was obtained by D1 treatment (100%) and the lowest ones (3.46 and 3.44 kg/m3) were obtained by D2 (75%) and D3 (55%) treatments, respectively. Analysis of variance showed that irrigation with urban treated wastewater had a significant effect on dry matter yield, ear length and water use efficiency based on dry matter. Therefore, the refined wastewater at level of 75% water requirement can be suggested as a suitable irrigation practice for corn in Pakdasht area.

This research is based on the results of a study that was carried out to evaluate the effect of direct drilling of wheat in maize residues on yield and water productivity (WP) for two years of 2016 and 2017. For this purpose, a field experiment was conducted as split plots with a randomized complete block design with three replications in Safiabad Agricultural Research Center located in Dezful, north of Khuzestan province. The main plot treatments were including: No-Tillage (NT), Minimum Tillage (MT), and Conventional Tillage (CT) and sub plots treatments were Chamran 2, Mehregan, Shoosh, Falat, and Darab 2 cultivars. The results showed although there was no significant difference between tillage methods, but the average yield of cultivars in the NT (4830 kg ha-1) was more than the MT (4610 kg ha-1) and CT (4680 kg ha-1). On the other hand, the average yield and WP of both Mehregan and Chamran2 cultivars (5000 kg ha-1 and 1.25 kg m-3,respectively) were more than the other cultivars. Although in this research, reducing passes of tillage and planting machinery from 6 to 7 times in MT and CT to only 2 times in NT method (chemigation and planting in maize residues) did not have a significant effect on the soil cone index and soil bulk density, the soil organic carbon increased 16 to 32 percent in NT method in comparison to other tillage methods. Therefore, the use of new wheat cultivars under direct drill planting conditions in maize residues without yield reduction and 3-4 percent WP improvement is recommended in similar areas.

In order to study and evaluate drought stress indices on yield, grain yield components, oil yield, seed oil percentage and sesame grain water use efficiency, a field study was carried out as split plots in randomized completely block design with three replications in 2018-2019 in Behbahan Agricultural Research Station. The main factor was the amount of irrigation water at four levels (40, 60, 80 and 100% of crop water requirement) that was applied by drip irrigation system since the beginning of flowering stage and the sub factor was sesame varieties including Darab1 and Dashtestan2 cultivars. The average applied water in 40, 60, 80 and 100% of crop water requirement treatments and also in control treatment (surface irrigation) were measured to be 350, 414, 478, 542 and 651 mm, respectively. The comparison of average water use efficiencies in different treatments showed a high value (0.240 kg/m3 of sesame seeds) for Darab1 cultivar with 100% crop water requirement, identifying as superior treatment. Also, the results of Pearson correlation coefficient showed by increasing plant height, number of seed in capsule, number of capsule per plant, 1000-seed weight, volume of applied water, the seed oil yield and water use efficiency increase. Finally, due to lower values of SSI and TOL indices and higher values of STI, MP and GMP indices in Darab1 variety compared to Dashtestan2 variety, Darab1 variety could be introduced as superior treatment in term of drought stress.

Improving water efficiency in arid and semi-arid regions is an ongoing goal in agricultural production. Mulching is one of the important agronomic practices in conserving and modifying the soil physical environment. The objective of this research was to investigate the effect of mulch cover on soil temperature and water content in two sandy and loamy soil textures in the presence of shallow groundwater (60 cm). A factorial experiment was conducted in a completely randomized design with three factors (mulch, depth and soil texture). For this purpose, soil moisture content and temperature at different depths of 5, 10, 20, 30 and 50 cm were measured over 90 days. Soil heat flux was also calculated in this period. The results showed that the effect of mulch cover on soil moisture and temperature distribution in both soils was significant at 1% level with retaining a moisture content of 20-25% in surface layer (5 cm). These could be attributed to the role of mulch cover on shaping temperature equilibrium in soil profiles and reduction of surface evaporation. The interaction between the mulch and soil texture on soil temperature profile was also remarkable (p<0.01). Daily temperature fluctuations in the surface layer of loamy soil with and without mulch cover were measured 11 and 17.5 °C, and in the sandy soil, 14 and 18.5°C, respectively. Total heat flux in the 5-10 cm layer of loamy soil with mulch was approximately 40% less in comparison with the bare soil highlighting the effect of mulch cover on alternation of soil surface energy balance especially during daytime.

Emitters clogging is one of the most important problems in the operation of drip irrigation systems and also it is one of the main obstacles to the development of this irrigation method. To investigate the effect of discharge, operating pressure and management of irrigation system on clogging, emitters with discharges of 4 and 8 l/h, under three different operating pressures (1.0, 2.0 and 3.0 bar) and under three irrigation management methods (four, two and one times flow cutoff in every four hours operation) were tested for 132 hours. Accordingly the research included 18 treatments with four replicates which lasted for four months from July to October. In order to monitor the clogging in a limited time, 0.5 g/l of chalk was added to the water reservoir of the system. After 12, 36, 84 and 132 hours of the system operation, the clogging percentage of 4 l/h-emitter was 1.49, 1.12, 1.14, and 1.07 times more than the clogging percentage of 8 l/h-emitter. Discharge reduction in emitters under higher operating pressure was less than that in emitters under lower operating pressures. After 132 hours of system operation, the clogging percentages in emitters under operating pressures of 1.0, 2.0 and 3.0 bar were 91, 86 and 17, respectively. The effect of irrigation management method in treatments under operation pressure of 1.0 and 2.0 bar did not show a clear trend. Although, there was no meaningful difference between experimental treatments in emitters under 3.0 bar operating pressure, but in those with less flow interruption per the same operating time, less clogging was observed.

In this paper, direct loss to structures and their properties due to rivers’ floods in urban areas was investigated. Risk evaluation and flood management require an algorithm for evaluating economic loss due to flood. In this research, hydraulic properties such as depth and flow velocity were used to detect the destroyable areas during the flood event. Then the flow depth was used to estimate the economic loss due to floods with different return periods; 2, 5, 10, 25, 50, 100 and 500-year. The economic loss due to floods was calculated using the depth–loss functions of five different models. Furthermore, the costs of expected annual damage (EAD) for structures in the study area were determined for plan floods, of which the critical areas at the region were distinguished. The results showed that using depth-loss function of Arrighi et al. (2013) is more logic in the study area and it can be employed for risk management and flood insurance studies when the proper data are not exist. Finally, the depth-loss functions’ uncertainty were investigated using the First Order Variance Estimation (FOVE) method and the estimated loss confidence interval was determined. The procedure introduced in this paper provides a tool for rapid and acceptable approximation for risk assessment in urban flood-prone areas, especially where detailed information about structures and their pertinent properties cannot be provided.

The main application of spillway in rivers and dams reservoirs is control and diversion of flood and protection of their related structures. In this research, a laboratory study was performed to test 16 trapezoid piano key A type weir models with different pillars 10, 15 and 20 cm in a canal with 10 meters length, 0.6 m width and 0.6 m height. The proposed weirs were placed on the main canal wall with two arrangements. The results showed that the maximum overflow rate coefficient was corresponded to weirs with p=15cm in both arranments (1 and 2) and the dimentionless ratio of 0.4 <H/P> 0.2 0.4 and also to weir with dimentionless ratio of 0.5 <H/P and p=20cm. Finally, the trapezoid piano key weir with a p=15cm and a B=50cm identified to pass the most appropriate flow regime.

Land suitability evaluation by parametric methods (Story and Square Root) are sometimes incompatible with the reality of the field because of the low achieved values of the index. Therefore, the use of new multivariate decision-methods, considering the interactions of the criteria, including the new TOPSIS approach, can be investigated. Based on the grided sampling method, 22 soil profiles were studied in 8210 hectares. The genetic horizons were sampled and physicochemical properties analyzed. Based on the integration of soil unit map and slope, 17 land units were extracted and finally, land suitability maps were prepared for all three Story, Root and TOPSIS parametric methods in land units and GIS. Comparison of the values of land suitability index and yield of corn in the studied units showed that the correlation coefficient are 0.76, 0.76 and 0.78 for Story, TOPSIS and Square root method respectively. The results of this study showed that the Square root method has more validity than the other two methods

In this research in order to find and investigate the trend of dusty day events and their relation to climatic variables (maximum temperature and maximum wind speed), hourly and daily dust data and also weather data of 10 synoptic stations with common period (2000-2014) in Lorestan province were studied. For this purpose, data normalization was examined by Kolmogorov-Smirnov test. The non-parametric Mann-Kendall and Spearman’s tests at 95 percent confidence level were used to investigate the trend of dusty events. Inverse distance weighting (IDW) method in Arc GIS software was employed for zoning Mann-Kendall indices of dust and climatic variables. In order to find a correlation between climatic variables and dust events, the weather data (as independent variables) and the frequency of dusty days (as a dependent variable) were analyzed by Pearson correlation method. Among ten series of seasonal data, Azna, Aligudarz and Kuhdasht stations had a high significant correlation between climatic variables and the frequency of dusty days. As in Azna station, the maximum wind speed variable (with 0.55 correlation coefficient), in Aligudarz station, the maximum temperature variable (with 0.78 correlation coefficient), and in Kuhdasht station, the maximum wind speed variable (with 0.82 correlation coefficient) had the highest correlation with dust events.

Investigating the leaching amount of trace elements from environmental pollutants such as tailings is very crucial for determining the risk of these materials and sustaining environmental quality. This research was carried out to determine the concentration, risk level and leaching behavior of lead from Zn-Pb mine tailing of Zanjan. For this purpose, two composite samples (0-20 cm) were taken from both types of tailings from the Zn-Pb mine and the pH, time, particle size and liquid to solid ratio was determined using a batch leaching test. Determination of elemental composition and mineralogical characterization of mine tailings were performed using x-ray fluorescence (XRF) and x-ray diffraction (XRD) analytical techniques respectively. The morphology of tailing particles was determined by scanning electron microscope (SEM). For evaluation of tailings risk level, leaching protocols such as Field Leaching Test (FLT), Synthetic Precipitation Leaching Procedure (SPLP), Toxicity Characteristic Leaching Procedure (TCLP) and Leaching Extraction Procedure (LEP) were used. Also, for identification of lead distribution among different fractions of tailings, the sequential extraction method was applied. The concentration of lead in all extracts was measured by ICP-OES. The results showed that the time, particle size, pH and the liquid to solid ratio are more effective on the concentration of lead leaching from tailings and the maximum concentration of lead discharged from the tailings occurred in a different range of particle size. The maximum amounts of lead in the studied tailings were respectively observed in residual, carbonaceous, exchangeable, organic, iron and manganese oxides and solution parts. The results of the leaching protocols also made it clear that both types of waste have great environmental effects and are considered to be hazardous waste residues. Therefore, special measures should be taken to safely store these substances in the environment and prevent lead leaching.

The growing number of areas facing to water scarcity necessitates adaptive water management strategies beyond traditional water supply and demand management methods, which are becoming increasingly difficult in many regions. Water reallocation offers a flexible water management approach to mitigate water scarcity under changing socio-economic, climatic, and environmental conditions. This study develops a complex system dynamic model (SD) reflecting interactions between water resources, Environmental water demand and socio-economy using SD software package ‘‘Vensim PLE’’. Four alternative socio-economic growth patterns and three alternative schemes are designed to simulate those impacts. The results reveal that the developed SD model reflect the dynamic behavior of the system in the studied area efficiently. In the meanwhile, by comparing the different scenarios, it can be found that a higher growth pattern with desirable scenario supply socio-economic growth and environmental water requirements. It should be explained that the maximum growth pattern allows policy makers to revive the aquifer balance by controlling demand and adopting methods such as increasing artificial aquifer feeding and purifying treatment of urban and industrial wastewater.

Regarding the occurrence of hydrological drought after the meteorological drought, determining the relationship between these two droughts is necessary. In this study, the Zayandehrood Basin in the central part of Iran was selected as the study area. Selected stations in this basin; Damane Fereydan station, Ghaleh Shahrokh station (upstream of dam) and Zamankhan bridge station (downstream of dam) were considered according to their location and trend of precipitation data. Initially, on the basis of monthly rainfall and flow data from 1360 to 1389, the standard precipitation index (SPI) and the standard flow index (SSI) (Meteorological droughts and hydrological drought, respectively), each with a three-month period were calculated. Then using the Run theory, the meteorological and hydrological drought characteristics, including the duration and magnitude of drought were identified. In the following, using R software and programming in it, the best model was sought to investigate the relationship between meteorological and hydrological drought. According to the number of samples, the model was also validated. The relationship in which a hydrological drought reacts to the meteorological drought is created using a nonlinear function model in Qaleh Shahrokh and Zaman Khan Bridge stations, which show the condition without the reservoir and the condition affected by the reservoir, respectively. The results showed that there is a nonlinear relationship between hydrological drought and meteorological drought and the threshold at which a hydrological drought begins to react to meteorological drought is achieved with respect to the nonlinear function model. The exponential function model with the appropriate validation indexes as well as high coefficients in both stations was selected as the best model. The duration and magnitude of hydrological drought at Qaleh Shahrokh station is 1.7 and 1.9, respectively. Also, the duration and magnitude of this drought at the Zaman Khan Bridge (under the influence of the dam reservoir) is 0.55 and 1.45. Originally, the time of occurrence of hydrological drought in the downstream of the dam will be occurred faster. These findings indicated that the operational activities of Zayandeh Rud reservoir significantly reduced the duration and amount of hydrological drought as compared to non-reservoir conditions.

In the current study, the effect of land use change on groundwater level in Isfahan-Borkhar, Najafabad and Chadegan plains was investigated during 25-year period (1990-2015). To provide land use maps, firstly Landsat images of years; 1985, 1994, 2006 and 2015 were provided and then the nearest neighbor algorithm of object-oriented method was used for images processing. In addition, the zoning maps of groundwater level in annual scale were prepared using Kriging method. In order to investigate the differences of piezometric data among different plains and also the effect of land use types on groundwater level, the analysis of variance (ANOVA) test with repeated measure was used. The results showed that in Isfahan-Borkhar and Najafabad plains, the average groundwater level of rangelands had a significant difference with other land uses. In addition, investigating the interactive relationship of the land uses change percentages and the groundwater level decline showed a serious decrease in groundwater level of both Isfahan-Borkhar and Najafabad plains in the last years, in spite of reduction in agricultural land use during the study period. Furthermore, according to the obtained results, the groundwater level drawdown in Chadegan Plain as compared with two other plains was mainly affected by increasing agricultural lands.

Nowadays, one of the environmental issues is pollution of soil, water and plants resources with heavy metals. Antimony (Sb) is one of the most dangerous heavy metals, which by accumulation in the plant and animal tissues and transmission to the food chain, endangers human health. The critical limit for Sb in drinking water has been determined by the European Union and the United States to be 5 and 6 μg/l, respectively. The World Health Organization has reported this limit for the soil, 35 mg/kg. Exposure to Sb with various concentrations can cause a variety of diseases, cancers and genetic defects in humans. In addition, it causes keratitis, dermatitis, conjunctivitis, and gastritis. Concentrations above the critical Sb level in the soil can cause oxidative stress and reduce plant biomass, germination, root length, plant height, and plant photosynthesis. This element has a negative effect on microbial communities and soil enzymes and the rate of inhibition of soil microbial populations has been reported as bacteria> fungi> actinomyces. In general, the absorption of Sb by plants in acid soils is lower than calcareous soils and solutions for reducing Sb absorption in calcareous soils are to use phosphate fertilizers (antagonistic effect of phosphorus with Sb), fertilizers containing sulfur and the use of organic materials. Considering the existence of two volcanic formations in the country (Urmia-Dokhtar and East of the country formation) that contain various types of heavy metals, including Sb and increasing the exploitation and the number of Sb mines in the provinces of West Azerbaijan, Sistan and Baluchestan, Kurdistan, and Khorasan Razavi, it seems necessary determining the pollution levels of the water and soil resources of these provinces, as well as the provinces located on the two above-mentioned formations. Also, in the provinces of West Azerbaijan and Sistan and Baluchestan, the treatment of drinking water in terms of contamination with Sb should be on the government's agenda.