نشریه دانش آب و خاک
سال سی و دوم شماره 4 (زمستان 1401)

Groundwater is the most important for agriculture, drinking and industry. On the other hand, the quality of groundwater is the other essential aspect for human. The quality of groundwater overall depend on a few factors such as geological information and human activities. In this study, the quality of the groundwater of Asadaabad aquifer was surveid by using statistical and hydro geochemical methods. Asadabad aquifer is located in the west of Iran, which is about 926 kilometers square. Thirty water samples were prepared in June of 2017. The samples were transferred to the hydrogeochemical Shahrood University lab.The factor analysis methods and hydrochemical methods were used to find the main component which influences groundwater. Additionally, the proposed method was used to cluster the groundwater of the Asadabd aquifer.The hydrochemical methods showed that dolomite information is the main factor that affects groundwater quality. Additionally, there are results of factor analysis in which the main component (weathering of carbonate rock) is the biggest quota from others. Using the results of factor analysis, hydrochemical surveying and the proposed method, groundwater was clustered in four areas, which are unique in water chemistry. The carbonate formation is the dominant set in the area. Using the statistical method and hydrochemical survey, the most important component, which affects groundwater, is the weathering of carbonate rock.Four areas are the output of the proposed method which used the result of the factor analyses and hydrochemical methods.

In order to increase the application efficiency and distribution uniformity in surface irrigation methods,some techniques such as the application of surge flow have been developed.One of the requirements for proper and efficient design of surge irrigation is to accurately determine the infiltration equation parameters.The purpose of the present study was to investigate the performance of three methods Elliott and Walker two-point, Shepard one-point and nonlinear regression methods in estimating water infiltration in furrow irrigation with surge flow.For this purpose,the field evaluation data of three experimental furrow included two furrows under surge flow and a furrow with continuous flow were used.The length and spacing of the furrows was 150m and 0.75m,respectively.The soil texture was clay loam.The results showed that the one-point method had the lowest performance in estimating the infiltration in furrow with surge and continuous flow.On the other hand,the results of nonlinear regression and two point methods were acceptable and close to each other.The mean values of root mean square error index for the one-point, two-point and nonlinear regression methods in estimating the advance times under surge flow were 10.85, 2.52 and 2.46 min,respectively, and in furrows under continuous flow were 8.87, 6.57 and 4.77 min, respectively.Also, the values of mean relative error in estimating the volume of infiltrated water in the furrows with surge flow were 42.12, 3.51 and 4.79, respectively,and for continuous flow were 7.70, 6.33 and 2.53, respectively.Results indicated that, the nonlinear regression method performed better in estimating the infiltration of furrow irrigation under surge and continuous flows.

Scouring around the bridge piers due to harvesting of river materials is one of the causes of bridge damage. Therefore, this study has investigated the scouring around the bridge pile group in the presence of material harvesting in several hydraulic conditions. For the first in this study, the surface of the piers was reinforced using gravel to reduce scouring. Comparing the results of scour depth of the reinforced model with simple model showed that the using of roughness caused maximum reduction of the scour depth in the flow of 45 L s-1 and Froude number of 0.1. After that, the maximum reduction of scour depth in other experiments was 64.29% and related to the flow of 15 L s-1 and the Froude number of 0.1. Also, the results of this section showed that the using of gravel on the surface of the piers reduced the rate of scouring and increased the equilibrium time. The results of time development of scour depth showed that in simple model the scour depth increased due to the increase in both Froude number and flow discharge, but in the reinforced model the scour depth increased with increasing Froude number but did not increase with increasing flow discharge. Evaluating of the scour area around the piers showed that the scour area increased with increasing Froude number and decreased with increasing flow discharge. The results of this study and its comparison with other studies showed the appropriateness of gravel roughness at the surface of piers to reduce scour.

Salmas plain aquifer is one of the aquifers in West Azerbaijan province, which is exposing to contamination risk of various contaminants from geogenic origin such as arsenic. This is due to hot springs and geological conditions of the area. Therefore, it is necessary to assess the contamination risk to arsenic contaminant and identification of high-risk areas in this aquifer. In this study, the contamination risk of Salmas aquifer was investigated using OSPRC method. In OSPRC method, the contamination risk investigated by considering the origin, source, pathways, receptor and consequence. In this method, the source of contamination was identified then specific vulnerability to arsenic contaminants as pathway was investigated using GMDH neural network model and six parameters of SPECTR method. The parameters of SPECTR method are slope, pH, electrical conductivity, hydraulic conductivity, water table and recharge. The testing RMSE and r values of the GMDH neural network model were 0.036 and 0.902, respectively. The contamination risk map was obtained by multiplying the specific vulnerability in the groundwater velocity. This map showed that the risk of contamination to arsenic contaminant is higher in the western and southwestern parts of the aquifer than the other parts of the aquifer. In general, the contamination risk of Salmas aquifer to the arsenic contaminants is very low.

Today climate change is evident as a result of increasing greenhouse gases and its effects in different parts of the world, especially in arid and semi-arid regions. Since groundwater is the most important source to provide water, is essential future to analyzes of the impact of climate change on these resources and the estimate the measure of their nutritional in the future. In this research, the effects of climate change on the groundwater resources of Qorveh plain in the watershed of the Tolawar River have been investigated. For modeling the groundwater level of the study area, the MODFLOW model was used for 216 months of calibration and then validated using 163 months' data. Finally, the predicted precipitation was entered into the MODFLOW model as the feeding parameter and the effects of climate change in the three scenarios A1B, B1 and A2 at the static-water level with aquifer simulation were investigated. Also, with a 10% increase in harvest volume from wells and Expected rainfall prediction from scenario A2, the drop in static-water level has increased dramatically and every year we will have about 117 centimeters decrease in the static-water level. With a 10% reduction in the volume of wells in the coming years and projected rainfall from scenario B1, drop of static-water level has decreased from previous years and the measure of reduction in the static-water level was estimated to be about 33 centimeters annually.

River flow contain fluctuations with very sharp ups and downs that act as unstable and chaos processes. The complexity of the behavior of such flow can be discovered and identified through the standard Hurst exponent and the generalized Hurst exponent or scale exponent. In this study, in order to identify the multi-fractal characteristics of large-scale and complex dynamics of Kashkan river flow, which has very strong fluctuations, multi-fractal detrended fluctuation analysis (MF-DFA) was used. The results of the detrended fluctuation analysis (DFA) show that there is one crossover with a time scale of 348-405 days in the daily signal of Kashkan river flow, which indicates the existence of fractal structure and different behavior of the time series of the river flow in different time scales. The Hurst exponent (h = 2) of small scales was 1.12, which indicates short-term memory and unstable structure of these time scales, while time series with a scale higher than this scale have a relatively stable structure. The strong dependence and gradual decrease of the generalized Hurst exponent on the degrees of fluctuation (q-order RMS) in the range of -5 to 5, on the one hand, shows the complex multi-fractal nature and dynamics, and on the other hand, the nonlinear memory of the Kashkan river flow signal. In addition, the multi-fractal nature and multiple scales of the river flow were confirmed in terms of the nonlinear relationship between mass exponent (tq) and q-order. The large width and asymmetry of the singularity spectrum, while expressing the intensity of the multi-fractal structure and different dynamics in the river flow signal, indicate the weight imbalance of the effect of large and small fluctuations on the river flow signal. The right tail elongation of this spectrum indicates the predominant effect of local fluctuations with small values on the structure of the Kashkan river flow time series.

Petroleum hydrocarbons are the most common organic contaminants in water and soil ecosystems around the world. Application of soil microorganisms is one of the cost-effective and environmentally friendly approaches to remove or reduce the oil pollution. Isolation and assessment of oil-degrading bacteria is the first step in bioremediation. Accordingly, the aim of this study was isolation of crude oil degrading (COD) bacteria from contaminated soil samples around the refinery and petrochemical plants of Tabriz and assessment of their ability in oil degradation.

In order to isolate the oil degrading bacteria from oil contaminated sludge collected from evaporation ponds of Tabriz Refinery, the carbon free minimal medium (CFMM) by enrichment methods were used. Based on bacterial growth indicators (e.g. optical density (OD) and microbial biomass, percent of crude oil degradation and production of biosurfactant), 20 efficient isolates were selected among the 60 isolates using CFMM supplemented with crude oil. All of these 20 isolates were evaluated by biosurfactant production tests. Then, 20 isolates were selected based on their growth rate, crude oil degradation potential, and their ability to degrade recalcitrant compounds (light naphta, heavy naphta, styrene and anthracene).

The most efficient strains that had the highest OD, microbial biomass and percentage of oil biodegradation with biosurfactant production ability were the isolates COD2-1,  COD1-5, COD4-3, COD4-2, COD9-3, COD6-3, COD7-1, COD3-1, COD1-1 and COD8-1. While other efficient isolates (COD1-4, COD5-6, COD4-5, COD7-3, COD4-6, COD6-1, COD6-4, COD2-3, COD8-2 and COD3-3) did not produced biosurfactant.  Among these bacteria, 11 efficient isolates were identified by molecular techniques. The results of molecular identification of bacteria showed that these isolates belong to the genus and species Stenotrophomonas sp.,  Achromobacter sp.,  Psedochrobactrum sp., Arthrobacter sp.,  Shewanella sp., Alcaligenes sp., Pseudomonas sp . and Acinetobacter baumannii. 

Among the isolates, the genus Stenotrophomonas sp., Psedochrobactrum sp., Arthrobacter sp. and Shewanella sp. with high quantitative and qualitative indices in terms of bacterial growth, microbial biomass, crude oil degradation and production of biosurfactant were the best candidates for bioremediation experiments in contaminated soil.

To recognize the effects of water deficit stress on physiological and agronomic responses of salt tolerant safflower genotypes, and introducing indices to selecting drought tolerant genotypes of safflower, an experiment was conducted as split plot based on a randomized complete blocks design with three replications in saline soils (6.7 dS m-1) of the East Azerbaijan Agriculture and Natural Resources Research and Education Center during 2017-18. The experimental factors included drought stress (non-stressed and stressed from flowering to maturity (and six fall safflower genotypes including: Padideh, Golemehr, Mexico14, Mexico248, Mexico295 and Parnian. Drought stress increased leaf temperature and decreased leaf relative water content (RWC), stomatal conductance and leaf chlorophyll index and also grain number per capitulum, oil percent, grain and oil yields significantly. Significant differences were seen among the genotypes in the above-mentioned indices (except for leaf temperature), yield components and seed and oil yields. Correlations among leaf temperature, RWC, stomatal conductance and leaf chlorophyll index with each other and with seed and oil yields were significant. Therefore, these indices (except for leaf temperature) can be used to select drought-tolerant fall genotypes of safflower in the region. Correlation among capitulum number per plant and grain number per capitulum with each other and seed and oil yields, were positive and significant. Hence, these yield components had important role in productivity. Golemehr, Mexico 14, Mexico 248 and Mexico 295 genotypes indicated higher seed and oil yields. It seems that the above four genotypes could be adapted to cultivate in saline areas around Urmia Lake and areas with similar climate.

In this research, a methodology is presented to evaluate the ability of plants for rill and gully erosion control in south of Ardabil province. The plants potential for controlling of concentrated flow erosion was determined based on a multi-criteria analysis. The stem density (SD), top soil erosion-reducing potential of plant roots during concentrated flow erosion (RSD), sediment obstruction potential (SOP), index of plant stiffness (MEI) and root cohesion (Cr) were calculated for 36 native plants (SD=1.216×〖10〗^(-4)-0.28, RSD=3.6×〖10〗^(-42)-10,1076, SOP=0.00082-0.988, MEI=1.69×〖10〗^(-6)-53.471 and Cr=5.432×〖10〗^(-4)-34.62). SD ranges from 0·26 to 28%. The plants Acantholimon talagonicum L. and Festuca Ovina L. have the highest stem density. These are small plant species with a good soil cover in spring and summer. SOP ranges between 0.00128 and 0.988 m/m. The plants Colutea persica Boiss., Melica altissima L., Festuca Ovina L., Verbascum thapsus L. and Amygdalus scoparia Spach have a high potential to obstruct sediment and organic residues. The results of the MEI calculations show that the shrubs and bushs Colutea persica Boiss., Amygdalus scoparia Spach, Tamarix ramosissima Ledeb., Salsola kali L. and Rhus coriaria L. are the most resistant to bending through flow shear forces (5.19-34.626N). Some plants such as Amygdalus scoparia Spach, Glycyrrhiza aspera Pall. or Stipa pennata L. have low RSD value that ranges from 6.68×〖10〗^(-24) to 3.6×〖10〗^(-42), and a high erosion-reducing potential through their roots during concentrated flow. Combined planting of plant species can be more effective in erosion control. The results can be used in adjacent regions and similar cold-semiarid and cold-arid environments.

Dates is one of the most important horticultural products in Iran, which has a special place in food security, economy, and trade in agricultural products. Now, Iran is one of the biggest producers of dates in the world, but the lack of water resources is one of the main challenges in producing this crop in Iran. Therefore, the purpose of this study is to investigate the water footprint of date production in Iran using three specific waters, namely blue water, green water, and greywater. Then, using the concept of virtual water footprint introduced by Hoekstra and Hang (2003), the water trade footprint for the date crop was calculated for the years 2018-2001. The results show that the average annual harvest of water resources for date production in Iran is 3.486 billion m3, a total of 69.752 billion m3 of water was consumed between 2001 and 2018 to produce dates in Iran. 68% (2.352 billion m3 per year and a total of 426.466 billion m3) of the total need for date irrigation in Iran through abstraction from groundwater or so-called blue water, 28% (0.976 billion m3 per year, A total of 17.526 billion m3 has been supplied through green water and 4 % (0.139 billion m3 per year, a total of 2.764 billion m3) has been supplied through grey water. Examination of water footprint of date production showed that to produce 1 kg of dates in Iran,

Several researches have been performed to investigate reasons of Urmia Lake dry out and solutions to stop Lake Shrinkage. In this research, by means of game theory and establishing five different scenarios, the Urmia Lake Conflict, has been discussed. Therefore, income of agriculture sector and water which is discharged to lake, are introduced as two players. In this non-cooperative game, the basin consumers sector was not allowed to consume more than 100% of Natural Renewable Water Resources and at least 3.5 billion cubic meters of water was allocated to Lake. Moreover, another hypothesis was that Agricultural Income should not be less than current amount. Based on above limitations, compared to other scenarios, the 4th scenario, in which, irrigated cropping pattern was completely prohibited and all orchards were irrigated using drip irrigation, presented the most desirable results. In the equilibrium, which was located at 4th scenario, Agricultural, Domestic and Industry sectors, consumed 26.78% of natural renewable water and 4235 mcm of water was allocated to Lake. Moreover, the agricultural income in this equilibrium was increased by 19% compared to current situation. At the equilibrium, as a consequence of crop irrigation prohibition, current costs diminished and therefore it might be in interest of farmers more than other scenarios.

One of the structures that is widely used for training the rivers and channels is groyne. From past time, application of the groyne indicates the wide advantages of these kind of structures. One of the important issues in the design of groynes is the local scour phenomenon in the nose due to changes in flow pattern and presence of strong vortices. In recent years, most research has been based on open and impermeable groynes, and most have been done in laboratory. Therefore, in this study, the scour and 3D flow pattern around the T-shaped gabion groyne were simulated using Flow-3D numerical model and turbulence model (k-ω) and compared with the experimental results. The results showed that the model (k-ω) has better agreement with the experimental results in predicting the maximum scour depth and flow pattern around the T-shaped gabion groyne. So that the location of scour and the maximum depth of scour obtained from numerical simulation are close to the experimental results. Increasing the body permeability also has a significant effect on reducing turbulence, eddy and transverse velocity.