JOURNAL OF WATER AND SOIL RESOURCES CONSERVATION
Year:2021 | Volume:10 | Issue:4|Papers Count:9

In this study, quantitative changes of groundwater resources were projected in Ardabil plain using HadGEM2-ES climatic output and Eureqa artificial intelligence tools for the three future periods (1418-1400, 1438-1420 and 1440-1458) under three emission scenarios (RCP2. 6, RCP4. 5 and RCP8. 5). The results showed that the largest decrease in discharge in summer will be 27%, while the increase in surface runoff in winter is expected to be 12%. The reason for this is the continuation of global warming, which will lead to faster melting of winter snow. The results of the models indicated a decrease in groundwater level in all months of the year in future periods, which has been significant in all periods-scenarios. The groundwater level will decrease between, on average, 1. 2% to-3. 2%. Reduction rainfall and discharge in the summer-which coincides with the growing season-will also intensify the increase in groundwater harvesting. This will exacerbate the water crisis in the region.

Optimal management of water resources in a plain with land uses requires proper prediction of water resources response using efficient models. In this research, Soil and Water Assessment Tools (SWAT) model was used to simulate surface and groundwater resources in Behshahr-Bandar-e-Gaz Plain. After analysis the sensitivity, calibration and validation of the model was performed based on river flow data of 2007-2013 and 2014-2017, respectively. Groundwater table simulation was done by simulating the recharge rate per hydrological response unit (HRU). The results of sensitivity analysis showed that the parameters GW_REVAP, GW_DELAY, SHALLST, DEEPST, RCHRG_ DP, ALPHA_BF, SOL_AWC, CN, HRU_SLP, ESCO, USLE_P, OV_N, FILTERW and EPCO were the most sensitive parameters. In order to evaluate of the model, the performance criteria of Nash-Sutcliffe (NS) and Correlation coefficient (R 2 ) were used. In the calibration stage, these coefficients ranged from 0. 56 to 0. 93 and 0. 74 to 1. 00, respectively, and in the validation process were in the range of 0. 56 to 0. 84 and 0. 66 to 0. 92, respectively, indicating the acceptable accuracy of the model in river flow simulation. Comparing the observed and simulated water table depths, NS (0. 81) and R 2 (0. 91) coefficients indicated the capability of the model to simulate groundwater level. According to the results of the water balance analysis, the most of the total water input to the plain ’ 6 % was used for evapotranspiration ’ parts as 18% and 22% allocetaed to surface runoff and infiltration, respectively.

Simulation of rainfall is considered as one of the most important issues of hydrologic field. Additionally, theartificial intelligence (AI) models own numerous privileges including acceptable accuracy, appropriateflexibility, and high speed. In this study, the long-term rainfall in Babolsar Station was simulated by means of anoptimized AI model. To do this, the extreme learning machine (ELM) and the wavelet transform (WT) werecombined. It should be stated that the monthly rainfall values from 1951 to 2019 were applied, meaning that 70% of the observed values were employed to training the AI models and 30% of rest were utilized to testing thesemodels. Firstly, the activation functions of the ELM models were evaluated; as a result, the sigmoid was chosenas the best activation function. Moreover, the lags of time series were introduced using the autocorrelationfunction (ACF) that four ELM models were defined through those identified lags. By performing a sensitivityanalysis, the superior ELM model was introduced. The values of correlation coefficient (R), variance accountedfor (VAF), and scatter index (SI) for the ELM model were respectively computed to be 0. 524, 27. 064, and 0. 819. Furthermore, different mother wavelets were examined and the “ dmey” was opted as the best mother wavelet. The wavelet transform enhanced the accuracy of the simulations significantly. For instance, the VAF index forthe hybrid WELM model equaled to 86. 461. It is noteworthy that the hybrid model was evaluated for differentdecomposition levels (DL) and then the best one was detected. Also, the (t-1) and (t-12) lags were identified asthe most effective input lags.

Considering the role of heterogeneous dams in flood control and also water storage, it is very important to consider the flow hydraulic in them. On the other hand, proper design of rockfill dams requires accurate study of flow behavior in these dams. In this regard, by studying the concrete-face rockfill dam (CFRD) in the present study, by creating different cracks on the concrete face of the dam in the laboratory model, the water infiltration behavior inside the dam body was investigated. Transverse cracks of concrete slab on concrete-face rockfill dam (CFRD) and water flow and how to control it in rockfill dams is one of the most important issues considered by experts in the design of dams. Determining the discharge coefficient of the groove to estimate the flow rate is important and unavoidable. The purpose of this study is to calculate the discharge coefficient of a rectangular groove located in the concrete surface upstream of the concrete-face rockfill dam (CFRD) in both submerged and free conditions. Variable geometric parameters in this study include the height of the groove from the bed, the angle of the groove located upstream of the horizon and, the variable hydraulic parameters include the height of the water head upstream of the rockfill dam. A total of 50 different experiments were performed and entered into the calculations. Finally, two equations were developed using dimensional analysis and nonlinear equation analysis, in order to predict the discharge coefficient of the upstream groove of a concrete-face rockfill dam in both free and submerged states. The developed equations are in good agreement (correlation coefficient of 0. 988 for free flow and 0. 984 for submerged flow) with experimental results. There is also a good agreement between the observed and computational flow using the predicted equation (0. 992 for free flow and 0. 989 for submerged flow).

The development of an accurate for monitoring the soil moisture is very important step in soil and water conservation activities and studies. The purpose of this study is to provide solutions to optimally determine the number of sensors required to monitor soil moisture bases on geostatistical approaches and intelligent monitoring of the water status in soil. In this research, 87 samples were taken as a regular network from the surface depth (030) cm. Three levels of the samples number were considered. By decreasing the samples number, the estimation accuracy decreases and the component effect increases, that indicates an increase in the random and nonstructural part of the property. With the high sample number, the fitness of the model was 1. 2% and 2. 7% more than when the average and the minimum sample number. Reducing the samples has increased the radius of effect and decreased the ratio of structural to non-structural variance of properties. So the radius of effect of field capacity when the sensors number is at its maximum level is 36. 8% and 38. 4% less than the other two levels, respectively. As the samples number decreases, the estimation error increases sharply. Based on the findings, the use of between 20 and 30 sensors per 100 hectares produced the best results. The kriging method was an excellent estimator for moisture mediation. The proposed method can be used in determining the optimal sensors number for irrigation planning.

According to Iran's semi-arid and dry climate, water as one of the limiting factors of production plays an important role in determining the type and combination of farming activities. Adverse effects of reduction of Water Resources in many areas of Iran's agriculture are considerable. It seems that these undesirable effects are so evident in Shabestar plain as one of the agricultural poles of the West Azerbayjan province and excessive underground water harvesting have affected the agricultural sustainability of the case study region. Determining optimal cropping pattern according to the resources and constraints of each region is considered as one approaches to the evolution in the agricultural system and moving towards sustainability. The main purpose of this study is to determine the optimal cropping pattern in the Shabestar plain subject to the water constraint. For this purpose, linear programming and goal programming methods were used, under some scenarios in order to achieve maximum profit and minimum water consumption. The results of optimal pattern under profit maximization goal show that the profit and water consumption increase by 382. 2 and 44. 3 percent respectively and also minimizing water consumption objective associates with decreasing 90. 6 and 22. 78 percent framing profit and water consumption, respectively. However, considering the optimal cropping pattern under the scenario of achieving profit maximization and minimum water consumption simultaneously, shows profit increase by 1. 1 percent and water consumption decrease by 4. 71 percent. Under this situation, the acreage of irrigated barley, rained barley and rapeseed had increased and also the highest increase in the acreage was related to the rapeseed, which is the strategic crop and the rained wheat also keep in the cropping pattern, which is more important in the nation food security.

Wind erosion and the movement of quicksands are considered as one of the important processes of land degradation and a serious challenge in Iran. In this study, an attempt was made to estimate the frequency of dust days in synoptic stations of Semnan province by considering the weather conditions. Also, the activity of sand dunes based on Lancaster index was examined. The results of this study during the statistical period of 15 years (2003-2017) showed Damghan station with 10% of erosive winds and 1058 days with dust and Shahroud station with 1% of erosive winds and 58 days with dust and Dust has the highest and lowest percentages of winds with speeds higher than the wind erosion threshold, respectively. The results of Lancaster index showed that Damghan city with the highest index has the potential of "fully active" wind sediments and therefore the stabilization of sand dunes is essential to reduce the damage caused by the activity of sand dunes in this area. The results of predicting the effects of possible changes in climatic factors on the mobility of quicksand in the selected station of the province showed that the sensitivity of sand mobility to changes due to increase in rain more than wind speed and to changes in decrease due to rain less than wind speed and if the average wind speed decreases by 30% in the future or the amount of rainfall increases by 30%, the condition of the hills will change from fully active to active.

According to the environmental crisis of the last two decades and the drying of some parts of the Urmia Lake and its impact on the surrounding agricultural lands, this study aimed to identify minerals in soils in different parent materials in order to understand the interaction of soils with parent materials and to predict their change trends. Twenty six soil profiles were described on different parent material and thirteen were selected as index profiles and studied precisely. Clay mineralogy results indicated the presence of clay minerals of illite, smectite, chlorite, kaolinite, vermiculite and palygorskite in this area. The presence of palygorskite in the profiles had two origins, pedogenic and inherited from parent material. Also, kaolinite and chlorite minerals are inherited from parent materials due to the lack of conditions for pedogenic formation. Illite was inherited in most soils and in profiles with agricultural use, potassium adsorption was carried out by expanded minerals and formed the illite on the soil surface. The origin of smectite was also pedogenic in some soils of this region, probably due to illite weathering, and in others it was hereditarym, Because they have also been observed in their parent rocks. Vermiculites in this area were also often of pedogenic origin and are derived from mica and chlorite. The results showed that different parent materials have a high effect on soil physicochemical and the amount of minerals in this area.

Aerosols play an important role in balancing Earth and atmosphere energy. In the last two decades, aerosols have been recognized as one of the key factors in the global climate change assessment. The purpose of this study, Determine the nature of atmospheric aerosols and simulation of the concentration of these particles in order to detect the sources of their emissions to the west and southwest regions of Iran. In order to, two types of information, including horizontal visibility of data from meteorological stations and the optical depth (AOD) MODIS were used Two dust events July 5, 2009 and July 1, 2008. In order to determine the nature of atmospheric aerosols, in the software of the ENVI 5. 3, the atmospheric aerosol particle size was calculated using the Deep Blue Aerosol Angstrom Exponent Land algorithm and mapped to the Arc GIS and Then they were analyzed. In order to detect the particle emission sources and Simulation of their concentration was performed using the WRF-Chem coupled numerical model, using the advanced MADE-SORGAM scheme. The results of the remote sensing method showed that the aerosol particles in the western and southwestern regions of Iran have a dusty nature. According to the output of the WRF-Chem numerical model in the both of the dust events, the northwestern regions of Iraq and its center were identified as the main sources of dust emissions.