hydrogeology
maryam bayatikhatibi; Faeze Rostami; Khalil Valizadeh Kamran
Abstract
In the Drastic model, the vulnerability index was obtained from 57 to 165, which is in the descriptive division into classes without risk to high risk of pollution, which if we consider three classes without risk of pollution to low pollution, we can say 44% of the total area of the plain is located ...
Read More
In the Drastic model, the vulnerability index was obtained from 57 to 165, which is in the descriptive division into classes without risk to high risk of pollution, which if we consider three classes without risk of pollution to low pollution, we can say 44% of the total area of the plain is located on these three classes. Also, three classes of low to high, occupy 46% of the plain area. In fuzzy modeling, after scaling and overlapping seven input layers, we prepared the final map, which according to the index of this modeling, 47% of the total area of the plain has high vulnerability, that the result obtained is very similar to the result of DRASTIC method, but by comparing the two methods, it becomes clear that the fuzzy model is more accurate than the drastic method. In both maps, the northwestern to southwestern parts where the city of Tabriz is located, have the highest potential for pollution and the southwestern parts, which include the Sahand Mountains, have the lowest potential for pollution. Finally, using GQI index and according to drinking standard WHO and using ten parameters: hydraulic conductivity, chlorine, calcium, bicarbonate, magnesium, potassium, total soluble solids, sodium, sulfate and total hardness which are taken from wells in the plain, In high-risk areas, due to the high percentage of total soluble solids, total hardness and high hydraulic conductivity, water quality has also decreased and descriptively, the water quality of Tabriz plain is in the acceptable to appropriate range.
Geomorphology
leila aghayary; Mousa Abedini
Abstract
Therefore, the purpose of this research is to investigate and analyze the most important factors involved in creating the risk of subsidence in the Ardabil plain and to identify the susceptible surfaces that are likely to be involved in subsidence in the near future. The purpose of this research in the ...
Read More
Therefore, the purpose of this research is to investigate and analyze the most important factors involved in creating the risk of subsidence in the Ardabil plain and to identify the susceptible surfaces that are likely to be involved in subsidence in the near future. The purpose of this research in the first stage is to evaluate the subsidence using radar interferometry technique in the Sarscape software environment, using the capabilities of A1 Sentinel images in the time frame of 2016 and 2021, and also in the following, in relation to the zoning of susceptible areas with the algorithm Aras multi-criteria was implemented in Edrisi software environment. The results of the present study showed that between 0 and 22 mm of subsidence has occurred in the studied area, and the highest amount of subsidence is concentrated in the central part and then in the eastern and north-eastern parts. According to the results of subsidence risk zoning; The criteria of water level drop, distance from the river, geology, and land use are the most important factors involved in creating the risk of subsidence in the study area, respectively, with a weighting factor of 0.221, 0.166, 0.152, and 0.147, respectively, and 267/41 and 403/21 square kilometers of the range have a very high probability of danger. Finally, it can be said that the most important factor involved in increasing the amount and potential of subsidence in the Ardabil plain is the excessive use of underground water and the drop in the water level.
Farnaz Daneshvar Vousoughi; Rasoul Samadzadeh
Abstract
1-IntroductionNowadays water resources management is a vitally important task and is the optimum planning of irrigation projects, and the development and exploitation of water resources especially during drought and flood events are strictly dependent on the accuracy of the used rainfall-runoff modeling ...
Read More
1-IntroductionNowadays water resources management is a vitally important task and is the optimum planning of irrigation projects, and the development and exploitation of water resources especially during drought and flood events are strictly dependent on the accuracy of the used rainfall-runoff modeling tool. Therefore, different models have been already developed and employed for modeling rainfall-runoff processes of the watersheds (Partovian et al., 2017).The wavelet-based pre-processing approach in the present study was used in the modeling of runoff time series via ANN. Furthermore, the impacts of denoising (smoothing) and wavelet transform have been simultaneously investigated in the accuracy of runoff prediction for one month ahead at the outlet of Ardabil plain.2-Methodology2-1-Case of the StudyThe plain of Ardabil (38 – 38 N and 47 – 48 E), locatedin north-western Iran, covers an area of about 990 km2 (see Fig. 1). In the present study, the trend analysis was carried out on the rainfall (P) and runoff (R) parameters for three stations including Samian (PS, RS), Gilandeh (PG, RG), and Kozatopraghi (PK, RK)) located in the Ardabil plain from 1977 to 2019. The data sampling has been reported in the one-month interval at all of the stations. Figure 2 shows the locations of the rainfall and runoff stations. In this study, five combinations of input data were consumed for runoff prediction as to the following:Comb. 1: RS(t), RS(t-1), PS(t); Comb. 2: RS(t), RS(t-12), RS(t-24), PS(t); Comb. 3: RK(t), RG(t), RG(t-1), PG(t-12), RK(t-12) Fig. (1): Case of the study and the position of rainfall and runoff stations.2-2-Artificial Neural Network (ANN) Three-layered feed-forward backpropagation, which is usually used in forecasting hydrologic time series, provides a general framework for representing the nonlinear functional mapping between a set of input and output variables.2-3-Wavelet transform (WT)In hydrological problems, the time series are usually in the discrete but continuous format; therefore, the discrete WT was used in the following form (Mallat, 1998):(2) 2-4-Wavelet based de-noisingWavelet de-noising technique is operated as follows: (1) an applicable mother wavelet and several resolution level methods are selected. An approximation subseries at the resolution level L and detailed sub-series at different resolution levels are decomposed from main time series xi (2) The absolute amounts of detailed-sub-series, which exceed the values of the fixed threshold are changed by the difference between the values of threshold and detailed sub-series.2-5- Efficiency criteria in runoff predictionTwo different criteria were used to measure the efficiency of the proposed forecasting methods; the root means square error(RMSE) and the determination coefficient (DC). 3-Results and DiscussionSome temporal features may also exist in the runoff time series due to their highly non-stationary fluctuations. To handle such features, wavelet-based temporal pre-processed data were entered into the ANNs to improve the accuracy of runoff modeling. WT and wavelet-based de-noising approaches were used for modeling the rainfall-runoff process via the ANN model. The Daubechies-4(db4) mother wavelet, which is almost similar to the runoff signal could capture the features of the signal, especially peak values, thus, it was selected as the mother wavelet for the decomposition of the runoff time series in this study. The decomposition of runoff time series at level L yields L+1 sub-signals (one approximation sub-signal, Pa(t) and L detailed sub-signals, Pdi(t) (i=1, 2, …, L)). Decomposition level 3 was considered as the optimum decomposition level. Each of the decomposed sub-series of the runoff demonstrated a specific seasonal feature of the process. In WT-ANN (WANN) model, decomposed sub-series accompanied by the rainfall and runoff data of each compound were used in the FFNN to predict one-month-ahead runoff values at the outlet of Ardabil plain (Samian station). In the second stage, the runoff time series were denoised via WT, and the denoised runoff data were used to predict the runoff at Samian station for one month ahead. Finally, the ANN model was compared with ANN models using pre-processing inputs.The results of three models for one-step-ahead runoff forecasting at Samian station have been presented in Table 1. Results indicated that better accuracy was comprised with another model via the WANN model in the comb. 3. WANN models via comb. 3 used the runoff data of Gilandeh and Kozatopragi that lied in the upstream and showed accurate performance. These demonstrated Gilandeh and Kozatopragi runoff time series played an important role in Samian runoff modeling. Accuracy improvement in the WANN model was 17%, 3.5%, and 35% combs. 1, 2, and 3 of inputs. The ANN model with denoised inputs showed little improvement (1, 6, and 6.2 percent in combs. 1, 2, and 3 of data) in runoff modeling at the outlet of the plain. Table (1): The results of ANN and SVM models for one-step-ahead predictionsInput combinationOutputvariableModel Type DCRMSE (Normalized) CalibrationVerificationCalibrationVerification1RS(t+1)ANNANN with denoised dataWANN 0.5920.5940.7910.4340.4380.5870.0650.0650.0470.0510.0520.0442RS(t+1)ANNANN with denoised dataWANN 0.7950.8130.7910.5670.6010.5870.0430.0390.0470.04340.0420.0443RS(t+1)ANNANN with denoised dataWANN 0.9070.8310.8800.7300.7750.8540.0290.0400.0320.0350.0320.0264-ConclusionsIn this study, the wavelet-based denoised data and WT were employed in ANN for rainfall-runoff modeling at the outlet of Ardabil plain using data pre-processing techniques. Accordingly, first, it was sought to smooth the hydrological time series by eliminating the outliers and large noises of raw observed time series, which may be due to human or tool measurement error or systematic error. Then, different sub-series were generated by decomposing runoff time series and used to train the ANN model for rainfall-runoff modeling. Using processed and unprocessed data, the obtained results were compared; this comparison indicated the merit of applied data pre-processing approaches due to robust identification of hidden patterns in data so that the developed models could simulate and predict runoff values with lower margin of error and higher confidence and the best results were achieved by employing the decomposed runoff data via WT having different training time series with the same components of original time series. For future study, it is recommended to examine the efficiency of the proposed data pre-processing method in the rainfall-runoff modeling of other watersheds since it is expected that the merit of the method is more highlighted where the quality of the collected data is blurred due to the technical limitations. Furthermore, it is suggested to evaluate the efficiency of the proposed method in modeling the process at other time scales and for modeling other hydrological processes which may involve distinct noise levels and patterns regarding the type of process.Keywords: Runoff modeling, Wavelet Transform, Wavelet-based de-noising, Artificial Neural Network (ANN), Ardabil plain5-References Donoho, D.H., 1995. Denoising by soft-thresholding. IEEE Transactions on Information Theory. 41(3):613–617.Mallat, S.G., 1998. A Wavelet Tour of Signal Processing, second ed. Academic Press, San Diego. Partovian, A., Nourani, V., Aalami, M.T., 2016. Optimizing Neural Network for Monthly Rainfall-Runoff Modeling with Denoised-Jittered Data. Journal of Tethys. 4(4), 284–294.
Hydrogeomorphology
Jafar Jafarzadeh; Meysam Argany
Abstract
Groundwater is one of the most important natural resources in arid and semi-arid regions. The purpose of this study is to identify areas that have groundwater capacity and to prioritize the factors affecting it. In this study, 11 indicators affecting groundwater capacity including Slope, Elevation, Aspect, ...
Read More
Groundwater is one of the most important natural resources in arid and semi-arid regions. The purpose of this study is to identify areas that have groundwater capacity and to prioritize the factors affecting it. In this study, 11 indicators affecting groundwater capacity including Slope, Elevation, Aspect, Distance from River, Drainage Density, Distance from Fault, Topographic Wetness Index, and Topographic Position Index, lithology, Land use and Relative Slope Position were used. 30% of the totals of 230 wells were randomly placed in the validation data group and 70% in the training data. To prioritize the effective factors and zoning of groundwater potential in Ghorichay watershed, the random forest method was used using ArcGIS and to evaluate the model of relative performance curve (ROC) and Area Under the curve surface (AUC). The results showed that the groundwater capacity of about 8% of the watershed is higher at the outlet of the watershed. According to the VIP diagram, the TWI layer with a value of 0.329 and the distance from the river layer with a value of 0.175 was the most and the least influential factors on groundwater capacity, respectively. The area below the AUC curve showed an accuracy of 87% in the training phase to identify areas with groundwater potential. The result of this study can be used in groundwater management in the Ghorichay watershed.
Alireza Habibi; Hamidreza Masoumi
Abstract
1-Introduction Many studies have been conducted on the water balance of watersheds based on the SWAT model, among which, one can mention the research of by Van Liew and Garbrecht (2003: 413-426), Neitch et al. (2005: 494), Abbaspour et al. (2007: 413-430), Rostamian et al. (2008: 977-988), Faramarzi ...
Read More
1-Introduction Many studies have been conducted on the water balance of watersheds based on the SWAT model, among which, one can mention the research of by Van Liew and Garbrecht (2003: 413-426), Neitch et al. (2005: 494), Abbaspour et al. (2007: 413-430), Rostamian et al. (2008: 977-988), Faramarzi et al. (2009: 486-510), Hoseini (2014: 63-73), Habibi et al. (2016: 275), Nadi et al. (2018: 61-79) and Ghazavi et al. (2018: 54-79). This research is based on the initial field observation and a question that, how much rainfall (rain and snow) transfer to groundwater with the performance of faults and rock units with high permeability? Therefore, according to the geological conditions, the Roodak basin upstream of the Latian dam was selected as the study area. So, SWAT model, field, and tectonic studies have been used to answer the research question. The Roodak basin has more than 420.41 square kilometers area. 2-Methodology The statistical indices of R2 and Nash-Sutcliffe (NS) were used as the most important evaluation criteria to quantitatively evaluate the performance of the ARC_SWAT model in the calibration and validation stages. Calibration and analysis of model were used and performed SUFI2 algorithm in SWAT Cup software and flow data of Roodak hydrometric station. Calibration for the years (2000-2007) and validation based on the statistics of the years (2008-2011) was performed after stimulation using calibrated values for sensitive parameters. Then the basin water balance check was obtained. The relationship between rainfall and permeability has been investigated based on geological components such as fractures, faults, and lithology. Mosha-Fasham fault and Latian fault are the main faults of the study area. The main controller of tectonic activities in the area is the Mosha-Fasham fault and its sub-branches. The main branch of this fault as a thrust has passed through the middle part of the basin and has pushed the Paleozoic and Mesozoic formations on the younger formations. Also, its sub-branches have caused disruption in the geological structures with normal and inverse functions. The northwestern part of the Latian fault is another important tectonic fracture of the Roodak basin and acts in the outlet parts of the basin. In this part, the Emameh River flows along the Latian Fault. The rock units of the region are divided based on field data and remote sensing studies of the 2019 Landsat 8 satellite image by Arc GIS software. From the lithological viewpoint, from old to new rocky and sedimentary units have respectively the following conditions. Red micaceous siltstone and sandstone of Zagoon Formation (Cz). Limestone and dolomitic lime, sandstone, and shale of Mila Formation (Com). Dark fossiliferous limestone and shale of Mobarak Formation (Cm). Oolitic limestone, thin-bedded shale and dolomitic limestone, and thick-bedded dolomite of Elika Formation (Tre). Grey shale and sandstone of Shemshak Formation (TRjs). Conglomerate, sandstone, and coaly shale of Shemshak Formation (Jk). Light grey massive limestone of Lar Formation (Jl). Light color massive orbitolina limestone of Tizkouh Formation (Ktzl). Polygenic red conglomerate and sandstone (Elc). Green tuff of Karaj Formation (Etu). Tuff with shale interbeds of Karaj Formation (Eksh). Dark green shale with tuff interbeds of Karaj Formation (Esh). Green tuff and Tuffy shale interbed of Karaj Formation (Ek). Red marl, gypsy marl, sandstone, and conglomerate of Upper red Formation (Mur). Recent sand and aeolian sand (Qsd). 3-Results and Discussion After running the model, the outputs including runoff, subsurface flow, etc., were obtained as a text file. Using the results of model, sensitivity analysis were identified nine sensitive parameters among the total 17 parameters. By SUFI2 algorithm were determined the optimal values of the sensitive parameters of the model. The results showed that the snowmelt and snowfall temperatures are the sensitive parameters of the model. The share of surface runoff, lateral, and groundwater flow in the monthly flow of Roodak River is presented in Table 1. Table (1): Water balance components of Roodak basi. variable Value (mm) Percent relative to rainfall Rain 585.67 100 Evaporation & transpiration 427 72.75 Water in the soil 10.44 1.78 Surface flow 18.49 3.15 Subsurface flow 118.72 20.27 Groundwater flow 11.35 1.93 Deep infiltration 0.68 0.12 The upstream areas of the basin have rock units with a relatively high permeability in terms of physical and dissolution conditions, based on geological data including fault, fracture, and lithology information. These rock units include limestone and sandstone of the Paleozoic and Mesozoic formations. Therefore, the expected power for the downward flow is high in these areas. In the middle and downstream areas, the intrinsic permeability of rock units is relatively low, due to Tuffy and marly lithology. However, the transferring surface water to depth is accelerated due to the extensive tectonic fractures. In contrast, disrupts this transfer to depths and makes subsurface flow the effect of secondary fillings on fractures. 4-Conclusions Generally, in simulating the Roodak basin flow the values of all indicators and the results of geological studies indicate the acceptable accuracy of the model. By running the ARC_SWAT model it was possible to simulate the monthly flow of the study period in this basin. Also, the statistical comparison has shown acceptable results. So the statistical comparison of simulation and observational hydrographs show a correlation of about 60% with the Nash-Sutcliffe criterion. This study provides useful information on the river flow and water balance of Roodak Basin and helps more accurately with water resources projects. The evapotranspiration potential (PET) is 1025.4 mm. The total water of the basin equal to 247.89 mm included surface runoff, groundwater, and lateral flow. Agricultural products temperature and water stresses were 129 and 80 days which calculated at the SWAT_ CHECK. Therefore, according to the simulation results, it can be inferred that the ARC_SWAT model has acceptable performance in the Roodak basin. Geological evidence indicates that the rock units have high permeability in upstream and low permeability in downstream areas. However, the results of the SWAT model showed that rainfall is flowing in the direction of the Emameh River slope in the form of subsurface flow. This is due to the action of Latian fault in the transfer of surface water to subsurface flow. Also, according to station data, water entering to Emameh River has the highest amount in winter and spring and the lowest level in late summer. Therefore, subsurface water as a base flow provides a significant part of the water in all months of the year. Surface runoff has a large share in the river flow from mid-autumn to early spring. Lateral flow accounts for a very small share of river flow in all months of the year. The simulation accuracy is acceptable in this research in comparison to the results with similar studies. The results of this study can be used by examining the impact of land-use change with different scenarios to predict the effects of management planning and climate change due to rainfall.
Groundwater
Mohammad Hossain Motedayen; Mehrdad Esfandiari; Abolfazl Moeini; Ali Mohammadi Torkashvand
Abstract
In recent years, the irreversible phenomenon of land subsidence has led to environmental hazards in various plains of Iran including Gorgan. In general, the most important activities causing this phenomenon are inappropriate groundwater withdrawal and geological factors. The research method consists ...
Read More
In recent years, the irreversible phenomenon of land subsidence has led to environmental hazards in various plains of Iran including Gorgan. In general, the most important activities causing this phenomenon are inappropriate groundwater withdrawal and geological factors. The research method consists of two sections: identifying subsidence areas and examining the effective factors and parameters and evaluating the impact of each. In identification section, radar interferometry technique was used to compare the phase taken from two radar sets from the same region at two different times and measurement of land surface changes over time can be achieved through interferogram, and in the effective factors analyzing section, the determination and analysis of effective parameters such as water level drop, texture and thickness of soil layers, especially fine-grained layers were investigated. The results of the satellite data analysis indicate that the region is steadily subsiding. The mean velocity map along the satellite line of sight obtained from time series analysis showed a subsidence rate of 14 mm / month (169 mm / year). The identified subsidence range is approximately eastern-western which is consistent with trends in structures such as the Caspian. Figures of water level and precipitation in this area during 2007 to 2009 show a decreasing trend despite of seasonal fluctuations, and analysis of effective parameters shows that the subsidence is due to the same drop in water level or the difference of same thickness of the fine-grained layer at different depths
watershed
Karim Solaimani; Seyedhossien Alavi; Fatemeh Shokrian; Esmaeil Mokhtarpour
Abstract
This study investigated the trend of hydroclimate parameters of the Miankaleh wetland using the Mann-Kendall test and Sen slope estimator. Temperature, precipitation, and evaporation parameters were used from the synoptic stations . Also, the discharge data were used from the hydrometric stations of ...
Read More
This study investigated the trend of hydroclimate parameters of the Miankaleh wetland using the Mann-Kendall test and Sen slope estimator. Temperature, precipitation, and evaporation parameters were used from the synoptic stations . Also, the discharge data were used from the hydrometric stations of Khalil Mahalleh, Tazeh Abad, Baghoo, and Vatana stations. The results of the Mann-Kendall test showed that the temperature in the Dashte-Naz station in spring and summer seasons has a significant increasing trend with 95% confidence and a significant decreasing trend in winter. Also, there is an increasing trend in Hashem Abad station, with a 95% confidence level in the spring and autumn seasons. Precipitation in Dashte-Naz station with a 95% confidence level has a decreasing and increasing trend, respectively. The most frequent trend changes in Dubai are related to Vatana station, which has a decreasing trend on an annual scale. Evaporation in Dashte-Naz station has a decreasing trend in the autumn and winter seasons and has an increasing trend in spring. Also, in Hashem Abad station, the evaporation rate in autumn has a decreasing trend. The Sen slope estimator method results showed that precipitation in Dashte-Naz station in December was -2.983, and on the annual scale, it is related to Hashem Abad station with -6.283. The highest monthly positive trend line slope of all parameters is related to August precipitation in Dashte- Naz station with a value of 3.20, and the highest annual scale is related to evaporation in Hashem Abad station with a value of 2.157.
hydrogeology
hamzeh saeediyan; Hamid reza Moradi; abdal salehpoor
Abstract
1-IntroductionSoil infiltration situation indicates soil behavior against water reaching the soil surface. This phenomenon determines the amount of both the water reaching the soil surface and rainfall losses. Soil infiltration of a basin has unique parameters based on its climate, soil conditions, and ...
Read More
1-IntroductionSoil infiltration situation indicates soil behavior against water reaching the soil surface. This phenomenon determines the amount of both the water reaching the soil surface and rainfall losses. Soil infiltration of a basin has unique parameters based on its climate, soil conditions, and buildings. Soils are a set of discontinuous particles among which pores exist so that water can move from a point with more energy to a point with less energy; this property is called the passage of water through continuous pores. Gachsaran marl formation has a thickness of about 1600 m and consists of salt, anhydrite, colorful lime marl, and some shale from a lithology point of view. The age of this formation is lower Miocene (Ahmadi, 1999: 714). Estimation of soil infiltration using various erosion components can be a useful method to determine soil infiltration in the shortest time and at the lowest cost.2-MethodologyIn this study, soil infiltration was estimated using erosion different components in different land uses in deposits of Gachsaran formation by selecting a part of the Kuhe Gach watershed of Izeh city with an area of 1202 hectares. The relationship between soil infiltration and erosion different components, such as sediment rate, runoff rate, and runoff and erosion threshold, in different land uses of Gachsaran formation was determined by the multivariate regression. Then, different erosion components were sampled at six points with three replicates and different rainfall intensities of 0.75, 1, and 1.25 mm/min in three land uses of rangeland, residential area, and agricultural land using a rainfall simulator. SPSS and Excel software was used for statistical analysis. A portable Kamphorst rainfall simulator used in this study has a plot size of 625 cm2, which determines the characteristics of soil, erosion, and water infiltration, and is suitable for soil research. It is used as a standard method to determine the soil infiltration of surface deposits in the field. The experimental plot area was selected 625 cm2 with a smooth gradient. The preparation of the testing area was followed by installing and setting the rainfall simulator and then starting a chronometer upon observing the precipitation on the screen. The amount of plot infiltration was determined at 10-min intervals (Kamphorst, 1987: 407).3-Results and DiscussionThe estimation of soil infiltration was acceptable and appropriate in some models in this study, which have a lower regression coefficient. Therefore, it is not possible to make appropriate comments about the estimation of the models only using regression coefficients and other statistical coefficients nor the significance levels of observational and estimated data as well as the minimum square mean of errors (MMSEs); in some cases, the MMSEs are not sufficient and require more studies (Jain and Kumar, 2006: 272). Despite scientific advances and improvement of measuring equipment, regression models are still used by researchers in different fields due to simplicity.4-Conclusions The results showed that the most positive and negative effects of different erosion components on estimating soil infiltration were related to sediment rate, runoff, and erosion threshold in all three mentioned land uses in three precipitation intensities (0.75, 1, and 1.25 mm min). Meanwhile, the role of sediment rate in estimating soil infiltration was slightly higher than runoff, and erosion threshold and runoff rate had no role in estimating soil infiltration in this method due to a high correlation of data.
Hashem Rostamzadeh; Mir Kamel Hosseini; Saeed Jahanbakhsh asl; Mohammad Omidfar
Abstract
The aim of this research is to investigate the accuracy of the heavy rainfall data (rainfalls of 25 mm or more) of Tabriz weather radar in a period of 8 years (2014-2021) and compare them with synoptic station data in basin. To compare and evaluate between meteorological stations and radar data, statistics ...
Read More
The aim of this research is to investigate the accuracy of the heavy rainfall data (rainfalls of 25 mm or more) of Tabriz weather radar in a period of 8 years (2014-2021) and compare them with synoptic station data in basin. To compare and evaluate between meteorological stations and radar data, statistics such as, correlation coefficient (R) and root mean square error (RMSE) were used. The comparison of the maps obtained from Doppler radar and rain gauge stations showed that the spatial distribution of precipitation from the two databases was not the same and the low and high rainfall areas did not match each other, so that the correlation coefficient between the radar and observed precipitation was 0.25. Also, the results of Kolmogorov-Smirnov test showed that considering that the obtained p-value (0.000) is smaller than the error value of the test (0.05), then the difference between radar precipitation data and ground observations is significant. In fact, the rainfall values recorded in the ground and radar stations do not provide a single result, and none of the statistical populations have a uniform distribution, therefore the radar rainfall data cannot be used instead of the rainfall data of the stations.
Groundwater
Sana Maleki; Vahid Nourani; Hessam Najafi
Abstract
Systems for assessing groundwater vulnerability are designed to protect groundwater resources from pollution. The DRASTIC method is a well-known approach for determining groundwater susceptibility. One drawback of the DRASTIC method is that it relies on expert judgment to rank parameters, which introduces ...
Read More
Systems for assessing groundwater vulnerability are designed to protect groundwater resources from pollution. The DRASTIC method is a well-known approach for determining groundwater susceptibility. One drawback of the DRASTIC method is that it relies on expert judgment to rank parameters, which introduces uncertainty. This study used a new generation of Fuzzy Logic (FL), called the Z-number theory, to estimate the specific vulnerability of aquifers and address this uncertainty. The specific vulnerability of the Ardabil and Qorveh-Dehgolan aquifers was estimated using two scenarios: the DRASTIC parameters as inputs and nitrate concentration values as output. The vulnerability of the aquifer was also evaluated by comparing the results of the proposed models with those of the DRASTIC model, which served as a benchmark. The analysis showed that the Z-number Based Modeling (ZBM), which considered data reliability and weighted the rules appropriately, produced higher-quality results than the classic FL. In the Ardabil plain, the ZBM yielded results that were 53% better (using seven inputs) and 184% better (using four inputs) compared to the classic FL. In the Qorveh-Dehgolan Plain (QDP), the ZBM produced results that were 127% better (using seven inputs) and 311% better (using four inputs) than the classic FL. The irregularity and non-linearity of the data, such as the high coefficient of variation (CV) in the Ardabil plain compared to the QDP, may contribute to the high CV value in the plains. Therefore, in plains with high CV, the quality of the extracted Z-number-based rules may be lower.
Geomorphology
vahid rahmatinia; Bakhtiar Feizizadeh
Abstract
In this study, 5 main DEM derivatives of 12.5 m ALOS satellite (slope layer, slope direction layer, curvature layer, cumulative flow layer and altitude layer) as well as Sentinel-2 satellite images and NDVI vegetation index were used as auxiliary layers. Segmentation in this area was performed using ...
Read More
In this study, 5 main DEM derivatives of 12.5 m ALOS satellite (slope layer, slope direction layer, curvature layer, cumulative flow layer and altitude layer) as well as Sentinel-2 satellite images and NDVI vegetation index were used as auxiliary layers. Segmentation in this area was performed using segmentation multi resolation method. In this segmentation, the height layer was given a value of 3, the curvature layer was given a value of 2, and the other layers were given a value of 1. Then, using Layer Values and Geometry algorithms and assign class commands, landforms located in the western and southwestern slopes of Zagros (Aligudarz city area) have been classified. The results showed that the use of Layer Values and Geometry algorithms and assign class commands have a good ability to isolate and classify landforms, so that 8 types of landforms (slopes, ridges, water areas, precipices, peaks, ridges, lowlands and lowlands) Kappa coefficient was 0.87 and overall accuracy was 91.71%. The ridge landforms form the largest part of the region and are the dominant landforms of the region and have a good distribution in different parts, but the peak landforms with the minimum area have formed only a limited part of the study area.
Geomorphology
shamsolah Asgari; samad shadfar; MohamadReza Jafari; Kourosh Shirani
Abstract
Sedimentation is one of the most important issues in the watershed. Due to the problems caused by sediment, it is necessary to investigate the relationship between hydrogeomorphic variables affecting sediment production and suspended sediment load in the watershed. The purpose of this study is to model ...
Read More
Sedimentation is one of the most important issues in the watershed. Due to the problems caused by sediment, it is necessary to investigate the relationship between hydrogeomorphic variables affecting sediment production and suspended sediment load in the watershed. The purpose of this study is to model the relationship between suspended sediment loads with hydrogeomorphic variables of the basin and to extract geomorphic features and their relationship with sedimentation in the watershed. By simple random method, two cows and conifers, which include 8 specific sub-basins and are equipped with hydrometric stations, were selected. Statistical multivariate regression method was used to analyze the relationship between geomorphic variables with sedimentation of each sub-basin. The results of the study of the relationship between geomorphic characteristics and sedimentation of sub-basins showed that the amount of sediment produced was positively correlated with slope index, roundness, drainage texture, rainfall, unevenness and basin area and was significant at the level of 0.001. In order to influence the variables on the sedimentation rate of the sub-basins, the principal component analysis and cluster analysis methods were used. The results showed that the three factors of roundness coefficient, slope coefficient and drainage texture coefficient of the basin explain 44.62, 25.22 and 16.74% of the variance of all research variables, respectively. In total, the three final extracted factors were able to explain 87% of the variance of all research variables.
Geomorphology
Ali Bigham; S.Asedolah Hejazi; Mohammad Hossein Rezaei Moghaddam; Jamshid Yarahmadi; Fariba Karami
Abstract
Changes in erosion and sedimentation of the basin are one of the most important factors that affect different parts of human life and natural life. it is very necessary to receive these changes quantitatively, which mainly take place under temperature fluctuations and climate changes in different regions, ...
Read More
Changes in erosion and sedimentation of the basin are one of the most important factors that affect different parts of human life and natural life. it is very necessary to receive these changes quantitatively, which mainly take place under temperature fluctuations and climate changes in different regions, in order to be more prepared to deal with its negative consequences. In this research, erosion and sedimentation changes in Hajiler watershed were investigated and predicted using GeoWEPP and SWAT models. Based on this, first, by using the data of the current situation of the Ahar synoptic station and using the SDSM model, the changes of the statistical period2020-2040 in three scenarios RCP2.6-RCP4.5-RCP8.5 were investigated, then simulation and prediction of erosion changes was carried out. and sedimentation was done under the influence of climate change by using popular models. The output of the SDSM model indicates an increase in temperature and a decrease in rainfall for the basin until 2040.And the analysis of the simulation results of the sedimentation rate of the models showed that in the studied basin, the GeoWEPP with the selection of the domain method has a suitable level in estimating the sedimentation rate compared to observational statistics. The final model was chosen to predict the amount of sediment in the mentioned period of the basin. Using the downscaled results of the atmospheric general circulation model, the sediment changes in the statistical period of 2020-2040 under the above mentioned three scenarios were estimated as -1.97, 4.45, and 2.98, respectively.
maryam bayatikhatibi
Abstract
1-IntroductionIn the drainage basins of arid and semi-arid areas where the ecosystem is not able to recover quickly, extreme care should be taken with land use. The hydrological effects of changes in land use are manifested in the form of changes in runoff depth, minimum flow, maximum flow, soil moisture, ...
Read More
1-IntroductionIn the drainage basins of arid and semi-arid areas where the ecosystem is not able to recover quickly, extreme care should be taken with land use. The hydrological effects of changes in land use are manifested in the form of changes in runoff depth, minimum flow, maximum flow, soil moisture, and evapotranspiration. Increasing runoff production in a particular area, in addition to increasing the potential for flooding, has other effects. Due to the type of soil and the topographic and climatic characteristics, the hydrogeomorphological changes caused by human encroachment on slopes and land use changes have been significant in Ojan Chai area (from the sub-basins located on the eastern slopes of Sahand Mountain). Due to erosion in the slopes of Ojan Chay area, it seems that the changes in the amount of runoff are very significant due to land use changes in the area. The study area is one of the rangelands of the country and unfortunately, cultivation is done in an unprincipled manner in the slopes that are not suitable for cultivation. In the coming days, the turbulence of the slopes will be intensified, the amount of runoff will increase, and the number of destructive floods will increase. Often, the soil of the slopes is severely eroded by runoff due to the extreme cultivation in the rangelands.2-MethodologyTo simulate the effects of land use change in a region or watershed, there are many hydrological models, one of which is the L-THIA. This model is a way to evaluate the long-term hydrological effects in a basin by which relative changes that occurred due to a change of use in the runoff can be simulated.The above model is a good tool to help measure the potential effects of land use change on surface runoff. This model is based on the Curve Number (CN) method of the US Soil Conservation Organization (SCS). Expresses CN values range between 0-100, where high values are for urban uses and low values are for areas with high permeability, such as wetlands and pastures with high vegetation density. One of the benefits of L-THIA is that it does not require calibrating the model with real area data. Model calibration is performed automatically using various default CN combinations available in L-THIA GIS. In this paper, to use the L-THIA model, station precipitation was prepared and Landsat satellite images (TM and ETM sensors) and specialized L-THIA software and Arc Map were used. In addition, the probability of a pixel being placed in a particular class is calculated, then the probability of its placement in other classes is estimated and classified according to the maximum similarity (maximum probability) in one of the classes. The above process is expressed based on Equation 1. (Eq.1). Where P (X) is the probability of the presence of the class wᵢ in the image, / x) wᵢ P (probability of each pixel with the spectral characteristic x belonging to the class wᵢ and p (wᵢ / x) the probability of belonging of each pixel with the spectral characteristic x appearing in the image Class wᵢ and p (X) is the probability of the presence of a pixel with a spectral characteristic. The error matrix, kappa coefficient and overall accuracy are used to evaluate the classification accuracy of the images using Equation 2.(Eq. 2). Where OA is overall accuracy, N is the number of experimental pixels, Pii∑ is the sum of the elements of the original diameter of the error matrix.The kappa index is calculated from Equation 3.(Eq. 3). Where po correctly observed, pc shows the expected agreement. The error matrix shows the interference or conversion of uses to each other. Land use maps have been prepared for two periods (1988, 2018) as well as land use change maps. 3-Results and DiscussionIn this research, using THIA L- model, the type of soil was determined according to the available soil maps, prepared samples, soil reports of studies of other organizations and field experiences, soil hydrological group in the study area as the basis of the model used. In the prepared map, it is clear that the range of hydrological group A is observed in the southern and southwestern parts. The area related to hydrological group B is mostly scattered in the northern, northeastern, and central parts. Hydrological group C is spread around the flood plains in the central part of the basin, and finally hydrological group D, which is the largest part of the basin surrounding Ojan largely.According to the land use map of 1988, the largest area is related to rangeland use with an area of 544.6575181 square kilometers and the smallest area is related to water use equal to 0.189899975 square kilometers. According to the land use map of the year 2018, the largest area is related to agricultural use with an area of 510.5889519 square kilometers and the smallest area is related to road use equal to 0.5715 square kilometers. Examination of runoff depth maps for 1988 and 2018 shows that significant changes have been made in terms of quantity and location. Examining the height of runoffs and comparing two different periods in a specific use in relation to changing the rainfall parameter shows that a change in the rainfall parameter can significantly increase runoff in agricultural areas. This situation in relation to the range of the gardens is different, especially in recent years, showing a complex situation. In the case of pastures between 2018 and 1988, there is no significant difference in the height of runoff. Runoff depth in different land uses and rainfall shows that in areas with low rainfall, the highest runoff height is seen in lands under agricultural use. With increasing rainfall, pastures produce the most runoff and again with increasing rainfall, the highest runoff production is related to agricultural lands. In agricultural lands, the amount of runoff has increased in three decades and decreased in pastures.4-ConclusionThe results show that over the past three decades, many rangelands have been cultivated. The area of agricultural lands has increased from 368.4917957 square kilometers in 1988 to 510.5889519 square kilometers in 2018. The results of calculations in such lands show that the height and volume of runoff has doubled from 1988 to 2018. In fact, increasing the area of cultivated land and land use changes from pasture to agricultural land has increased the amount of runoff. The results of studies on soils located on slopes show that the hydrological group of soils in this area is impermeable and with maximum daily rainfall that has increased in recent years, they can produce high-volume deep surface runoff in a short time. These slopes were considered pastures in 1988 (about 90 square kilometers of pastures have been converted into agricultural land). This has caused row crops to produce more runoff in these areas. The results of the studies with the model used and the result of this research in the area of Ojan Chay basin show that the main reason for the increase in height and volume of runoff was land use changes.Keywords: Land use changes, Runoff, Erosion, Flood, L-THIA model, Ojan Chay basin5-ReferencesKhaligi, B., Mahdavi, M., Sagafiyan, B. (2005). Investigating the effect of land use change on flooding using NRCS model, Natural Resources of Iran,vol,58,No,4,p 41-58.Razvizadeh, S., Salajegehe, A., Khaligi, S., Gafari, M. (2014). Investigating the effect of land use change on flooding using, HEC-HMS model (case study: Taleghan watershed) Journal of Rangeland and Watershed Management, Vol. 66, No.3, pp 373-386.Sadati, H, Golami, S., Sharifi, F., Ayobzadeh, A. (2008). Investigating the effect of land use change on runoff, Journal of Rangeland and Watershed Management, Vol. 4. No. 3, pp 301-315.-Hentati, A., Akira Kawamura, Hideo Amaguchi, Yoshihiko Iseri. (2010).Evaluation of sedimentation vulnerability at small hillside reservoirs in the semi-arid region of Tunisia using the Self-Organizing Map, Geomorphology, No. 122, 56–64-Kakembo,V., W.W. Xanga, K. Rowntree.(2009).Topographic thresholds in gully development on the hillslopes of communal areas in Ngqushwa Local Municipality, Eastern Cape, South Africa, Geomorphology, No. 110.188–194-Khairulmaini Osman Salleh and Fatemeh Mousazadeh.(2011).Gully erosion in semiarid regions,Procedia Social and Behavioral Sciences No.19, 651–661.Vahidi, Mohammadjavad; Rasoul Mirabbasi Najafabadi; Mohsen Ahmadi. (2020). Analysis and ranking of soil erosion prevention methods using multi-criteria decision-making methods in rural areas of Darmian County, South Khorasan, Hydrogeomorphology, Vol. 6, No, 23.209-233.Yamani, Mojtaba, Hamid Ganjaeian; Lila Garoso; Mahnaz Javedan. (2020). Identification of susceptible areas for the development of agricultural lands based on parameters Hydro geomorphology (Case study: Sanandaj city), Hydrogeomorphology, Vol. 6, No, 23.1-20.
hydrogeology
Sina Ziaye Shendershami; Abazar Esmali Ouri; Raoof Mostafazadeh; Ardavan Ghorbani
Abstract
The aim of this study was to investigate the factors affecting the decrease and change of groundwater level in Ardabil plain in two periods 1995 to 2005 and 2005 to 2015. The monthly precipitation data of Ardebil, Nir, Namin, Abi baglo, Hir, Samiyan stations in the Ardabil plain during the statistical ...
Read More
The aim of this study was to investigate the factors affecting the decrease and change of groundwater level in Ardabil plain in two periods 1995 to 2005 and 2005 to 2015. The monthly precipitation data of Ardebil, Nir, Namin, Abi baglo, Hir, Samiyan stations in the Ardabil plain during the statistical period of 1995-2015 and monthly data of the height of the station in 24 Piezometric well ring were chosen for the plain. Landslide OLI and TM satellite imagery was used to prepare land use map for the target periods in June 1993, 2005, and 2015. The results of land use changes in the years 1993, 2005, and 2015 in the Ardabil plain showed the highest watery agriculture with 48156.26, 50678.66, and 58356.68 and area water level, respectively, were with 168.75 ,88.65 and 380.95 ha, lowest level Which indicates the high level of agricultural land involvement in the decline of agricultural land in the Ardebil plain. The study of the process of Piezometric Wells showed that in the plain of Ardabil, the maximum height of the surface of the station (1437 m) is related to the southern parts of the plains around the village - Noshahr-Kargan and the minimum height (1300 m) is related to the village of Khalifaulo Sheikh. The highest level of cultivation is also focused on user plans in these areas.
hydrogeology
Mousa Abedini; Sajjad Javadi; Raoof Mostafazadeh; AmirHesam Pasban
Abstract
Today, soil erosion is one of the major problems of watersheds and agricultural areas and natural resources, which causes land degradation and decreases soil fertility. Therefore, the purpose of this study is to investigate the relationship between vegetation and geomorphic indices with the values of ...
Read More
Today, soil erosion is one of the major problems of watersheds and agricultural areas and natural resources, which causes land degradation and decreases soil fertility. Therefore, the purpose of this study is to investigate the relationship between vegetation and geomorphic indices with the values of erosion and sediment in the watershed of Koot-e-Tootraghi basin, which was done by using the capabilities of GIS to extract the geomorphic characteristics of the basin. For this purpose, erosion and sedimentation rates were calculated using the modified Psiac model (MPSIAC). Also, in order to extract physiographic and geomorphic features including: TWI topographic moisture layers, SPI current strength, SLOPE slope, domain curvature, profile curvature and sub-basin plan curvature, from the height digital model with a spatial accuracy of 30 meters, as well as other layers used in the MPSIAC model including1:25000 topographic maps, 1:100000 geological maps were used. According to the box diagram, the indices related to curvature have little changes in the studied area. Also, the indices related to curvature have little changes in the studied area. Based on the results, there is a positive and significant correlation of 0.47 (p-value less than 0.01) between the standard index of vegetation cover and topographic humidity index. In addition, there is a significant correlation (0.63) between waterway power index and slope. It was also found that the relationship between the slope and the normalized index of vegetation has an inverse and significant relationship (0.48) (p-value less than 0.01.).
elnaz piroozi; Aghil Madadi; Sayyad Asghari Saraskanroud
Abstract
1-Introduction Rivers are dynamic forms of natural landscapes with different changes at different times and places. The effects of river adjustment caused by the natural factors require much longer span to reveal. However, sometimes the natural factors such as river floods, landslide, or earthquake can ...
Read More
1-Introduction Rivers are dynamic forms of natural landscapes with different changes at different times and places. The effects of river adjustment caused by the natural factors require much longer span to reveal. However, sometimes the natural factors such as river floods, landslide, or earthquake can lead to canal adjustments in a very short time (Chaiwongsaen et al, 2019:153(. In contrast, human activities can have a significant and rapid impact on natural processes and trends, resulting in a short time scale for river adjustments (Rinaldi & Simon, 1998:57). River canal instability plays a major role in erosion, destruction of beaches and riverbanks. This role becomes more significant when the canal and bed of the river is alluvial (Rezaei Moghadam, 2012:33). One of the key issues in studying the erosion and stability of rivers is the initiation of sedimentary particle movement. The motion of sediments occurs if the bed shear stress (available shear stress) induced by the flow exceeds a certain critical value. An alluvial canal, either artificial or natural, persists to deform its boundary by itself while transporting water and sediments. Therefore, erosion and riverbank instability have created major concerns worldwide over the past few decades and significant amount of money have been spent to sustain the riverbanks. Givi-Chay River which is almost 54 kilometers long, is one of the permanent rivers of Ardabil province, Iran; problems of bed and bank erosion are evident in different areas of this river and they damage agricultural lands and adjacent river installations. In addition, a review of the research shows that sufficient studies have not been carried out so far to reveal the stability, erosion and sedimentation process in Givi Chay River.Therefore, this study aimed to analyze and evaluate the erosion stability of Givi Chay River channel. 2-Methodology In this research, the topography map with a scale of 1: 50000, geology map with a scale of 1: 100000, and google earth and Landsat Eight images, including OLI sensor (2019), bedrock maps and the Givi-Chay River area at a scale of 1:2000 hydrological data from two Abegharm stations (upstream of the dam) and Firoozabad (downstream of the dam) and field data are used. In addition, to control the results obtained by quantitative methods, field studies are applied for confirmation and verification. ENVI 5.3, Arc GIS 10.5, Excel, and HECRAS software were also used for image processing and data analysis. The geomorphological parameters of the river and their variations including bending coefficient and central angle were measured. The curvature coefficient is one of the few criteria used in river shape segmentation using s=1/(y.2), i.e., by dividing the valley length by wavelength for each arc, it is calculated. The central angle of the arcs on each of the intervals was calculated using the relation A=180L / Rπ, where A is the central angle, R, of the fitted circle radius.The increased shear stress in the riverbed increases the load of the floor and the scour of the bed, which can affect the riverbanks as erosion, destruction, and rupture of the walls. Direct measurement of shear stress is a difficult task and therefore researchers have developed methods for indirect calculation of shear stress. Existing shear stress (boundary), lateral shear stress, and critical shear stress were calculated by means of equation 1, 2, and 3, respectively: (1) (2) (3) Relative Stability Index Calculation (RBS):Judet has introduced this index as the ratio of critical bed velocity to actual bed velocity. Olsen et al (1997) defined this index as the ratio between the critical shear stress and the shear stress of the sides. Relative stability index (RBS) was obtained using the following equations: (4) (5) (6) 3-Results and Discussion Investigation of the morphology of the intervals shows that in the first, second and fourth intervals the conduit is sinusoidal and in the fourth interval, the pattern is meandering. In addition, according to the results of the study, the first, second and third intervals are developed in a very meandering manner and the fourth interval is just a meandering one. shear stresses in sections 4, 3 (second interval) are more than other sections, and given the direct relationship between shear stress and depth and width of sections, even under current conditions there will be phenomena such as scouring and damaging river bank and rivers. In addition, in terms of critical shear stress, the highest shear stress is in sections 3 and 7. Due to the relative stability values, sections 5 and 7 are stable and other sections are unstable. In the first period, the river flows into a valley bed, and in parts formed by erodible formations and at sections close to the dam, the river width is approximately increased. Therefore, sections 1 and 2, which pass through alluvial terrace sediments, are in unstable condition. In the second interval and immediately after the Givi Dam, the river passes through the valleys overlooking the Givi town, where the width of the bed due to the types of the banks decreases and the riverbed contains coarse sediments covered by broken rocks. In other parts of the city of Givi, erosion conditions prevail and large volumes of flanking material (especially during floods) are eroded and loose flanks lead to the widening of canals and intra-canal ridges, and these sediments are clearly visible in bends, middle islands and marginal lands and steep banks. At sections where the river width is excessive and the slope decreases, the stability factor is almost high (sections 5 and 7). At the beginning of the third period, Firouzabad area is located on path of the flood of the previous interval and by joining Sanghor Chay, the river enters the mountainous part and the coastal areas have deep valleys with steep slopes. Along the river, due to collision with high mountains and rocky outcrops, the alternate route has a meander and river changes are subject to valley changes, and the meandering state is seen throughout the valley. In the fourth period, the river width is reduced and the riverbed is covered with coarse sediments, which extends to Ghezelozan. 4- Conclusion(S) According to the study results, in the plain interval, the main factor affecting the river meandering is the alluvial formation; here, the slope is low and the meanders are inscribed and plain, whereas in the mountainous part, the river changes are subject to valley changes and the meandering state is seen throughout the valley. According to the values of shear stress, the lowest boundary and bank shear stress is in sections 5, 6 and 7 and the highest is in sections 4, 3, 11 and 12. The highest critical shear stress is in sections 3 and 7 and the lowest is in sections 4, 2 and 12. The study of the relative stability of the river shows that the river is more unstable in sections crossing the old and new alluvial terraces, and in sections where the river width is high and the bed slope and flow rate have a decreasing trend, the coefficient of stability is relatively high. The third and fourth intervals are mountainous and semi-mountainous, respectively. In these intervals the river width is small and there is no agricultural land use .Lithologically, most of the third and whole of the fourth period consist of Eocene igneous and pyroclastic formations and they are resistant to erosion and the existing alluviums are the result of transport of water from sediments of other intervals.Therefore, the morphology of the river is affected by lithology and according to field evidence, the interval is stable .But the results of using mathematical and experimental methods have introduced the third and fourth intervals as unstable . Therefore, it can be acknowledged that the methods used in this study apply to the study of stability in rivers and alluvial intervals
watershed
Razieh Izanloo; Ebrahim Omidvar
Abstract
The damming can cause changes in the hydrological regime of the river. There is a crucial need to understand the potential impacts of water structures on river hydrologic regimes in order to set managed environmental flows. In this study, the statistics of Tang Esferjan hydrometric station at the outlet ...
Read More
The damming can cause changes in the hydrological regime of the river. There is a crucial need to understand the potential impacts of water structures on river hydrologic regimes in order to set managed environmental flows. In this study, the statistics of Tang Esferjan hydrometric station at the outlet of Hoonejan watershed (Isfahan province) were used to investigate the monthly average discharge and flow duration curve alteration using IHA software (version 7.1). The amount of monthly flow has decreased in the post impact compared to the pre impact period. The flow duration curve is higher in all seasons before the construction of check-dams than after construction. The interpretation of flow duration curves shows the reducing effect of correction clauses in all types of flow. The hydrological indicators of the stream (normal discharge index in the high flow condition, normal discharge index in the low flow condition and normal discharge index) have decreased in the post-impact period compared to the pre-impact period. In all months of the year, except for February, March and April, the rate of decrease of the normal discharge index in the low flow condition (Q75) was higher than the normal discharge index in the high flow condition (Q25). The normal discharge index in the high flow condition has decreased more in the spring season than in other seasons after damming. The normal discharge index in the low flow condition in winter, autumn (91%) and summer (90%) has decreased more than in spring.
Hydrogeomorphology
Vahideh Moradzadeh; Zeinab Hazbavi; Abazar Esmali Ouri; Raoof Mostafazadeh; Shirin Zarei; Nazila Alaei
Abstract
Ecological indicators have become important tools for evaluating and monitoring natural resources. Understanding the relationship between biological activities and ecological interactions is essential to their structure. On the other hand, human activities have significant effects on landscape evolution ...
Read More
Ecological indicators have become important tools for evaluating and monitoring natural resources. Understanding the relationship between biological activities and ecological interactions is essential to their structure. On the other hand, human activities have significant effects on landscape evolution through changes in sediment production, transport, and storage. Therefore, this issue should be considered in the comprehensive management of different watersheds and ecosystems. Accordingly, the present study was conducted to evaluate the spatial heterogeneity of the hydro-sedimentologic disturbance index (HSDI) in the watershed located in the central part of Ardabil province. For this purpose, sediment transport (ST), hydrological stress (HS), recharge potential of groundwater (Rec), and soil erosion potential (SEP) were first calculated for 27 different sub-watersheds. Then, these factors were weighted using the Shannon entropy method. The hydro-sedimentologic disturbance index (HSDI) was calculated and zoned using the weighted average. The results showed that the mean, maximum and minimum values of the HSDI index in the Samian watershed were 10.17, 45.67, and 0.20, respectively. In addition, 87.67, 5.33, 5.32, and 1.68% of the watershed area were classified into very low, low, medium, and high levels of disturbances, respectively. Sub-watershed 19 located in the northern part, and sub-watersheds 20 and 21 located in the central part of the Samian watershed have the most disturbances, so they are prioritized for management actions. The present research framework can be used as a potential tool to support decisions that should focus on improving natural resource management.
Maryam Ansari; Iraj Jabbari; Farhang Sargordi
Abstract
1-IntroductionIran is one of the arid and semi-arid regions of the world with an average annual rainfall of 240 mm. The country is such arid that the average annual rainfall is less than 130 mm (Jafari and Tavili, 2013:149) in 65% of its regions; therefore, it has been facing a water shortage for a long ...
Read More
1-IntroductionIran is one of the arid and semi-arid regions of the world with an average annual rainfall of 240 mm. The country is such arid that the average annual rainfall is less than 130 mm (Jafari and Tavili, 2013:149) in 65% of its regions; therefore, it has been facing a water shortage for a long time. Thus, due to the limitation of surface and groundwater resources in the country, particularly arid and semi-arid regions, it is necessary to identify the factors affecting the quality of water resources for protection to reduce the vulnerability of these resources. Among the various factors that cause water quality degradation, the type and material of rocks or geology are crucial in changing groundwater quality (Jehbez, 1994: 1). Accordingly, in this research, the efficiency of the GWR model was measured to determine the sources of water pollution by selecting the Izdakhvat basin as a sample of inland Zagros basin that has good but saline water resources; these areas received the most impact from a particular formation.2-MethodologyIzadkhaast catchment, code 2647, is one of the closed basins of the Mond River catchment located in Fars province. The area of this basin is 1371.3 square kilometers the height and plain of which is respectively, 879.6 and 491.7 square kilometers of the total area of the basin. The maximum and minimum height in the basin are, respectively, 2182 and 1029 meters.In this study, the geographical weight regression (GWR) model has been used to investigate the relationship between geological formations, water quality parameters, and spatial modeling. This method is based on processing the hydrological information (water quality data) and geology using the GIS technique. The required parameters were considered as model inputs; moreover, geological map 1:100000 sheets of ZarrinDasht, Jahrom, and Bezenjan Geological Survey was used to extract geological data as well as the obtained data of observation wells, Fars Regional Water Joint Stock Organization. As the water quality data is related to 14 observation wells in 2010 (due to the more complete data), which is among 16 quality parameter data, after examining the relationship between the parameters together, those who had the highest correlation and significant relationship with the EC parameter, were selected for statistical analysis. They were also selected to quantify the geological formations. For each well, Polygon Thyssen was drawn. The area of the formations in each of the polygons was extracted and added as an independent variable to the descriptive table of the desired file shape, and then they were analyzed for modeling in ARC GIS environments in the following steps:1- First, to enter the best model for execution in the GWR method, independent variables related to trial and error in the OLS method were analyzed so that the best model with a significant relationship between variables, i.e., P value less than 0.05, R2 more and lower AICc coefficient was selected.2- After selecting the best model, the Moran index was used to evaluate the spatial autocorrelation of the OLS model residues. This index measures the degree of clustering or dispersion of standard residues. The residues were used to test the reliability of the model in predicting local conditions by experimenting with spatial correlation.3- Finally, the variables selected from the OLS model were entered into the GWR model to achieve higher precision in spatial relationship analysis. The GWR recorded local changes by weighing more close observations than farther ones (Pratt and Chang, 2012:52).GWR outputs include local residuals as well as the results of R2 or the coefficient of determination, where R2 is the standard for determining the performance of multivariate regression models.3-Results and DiscussionAccording to the results of the OLS model, the sign of beta coefficients for Aghajari Formation (MPLa), alluvial deposits Qc, and QScg were negative. They indicated their inverse relationship with qualitative parameters. However, most of the qualitative parameters were directly and remarkably related to seasonal lakes, salt dome (Pc CHD), Champe member (Mchm), and mole member (Mmo) in the area, which indicated surface erosion and leaching of salt and gypsum from the surface by surface currents and their transfer to the low points of the basin, i.e., seasonal lakes. These formations have also shown themselves as Mahour and Badland hills due to their instability against further erosion.After selecting the best models, all the standard residues of the selected OLS models were examined to ensure the normal distribution of the data and to evaluate the spatial autocorrelation using the Moran index. All residuals in the selected OLS models were within the standard range, indicating a normal data distribution.Finally, to better understand the correlation between geological formations and water quality parameters in different parts of the basin, the variables selected from the OLS model were entered into the GWR model. The results of this model have been presented as spatial model maps for each parameter based on the results of coefficients of determination (R2).According to the maps, the highest correlation was related to the potassium parameter, and the lowest value was related to the chlorine parameter, while the other parameters also showed a very high correlation with independent variables. In most qualitative parameters such as sodium, potassium, chlorine, and electrical conductivity, the highest correlation was related to the west of the basin, which indicated the high impact of the salt diaper in the west of the basin on water resources and wells that are close to the points of lower quality than wells in higher and farther points. Low resistance and erosion of evaporative sediments were also contributed to this issue, as water sources in contact with evaporative sediments may contain large amounts of potassium, sodium, chlorine, and sulfate in an insoluble form.4-ConclusionsThe results of this study revealed that this model with high spatial variability determined the impact of different formations on water resources in various places and critical areas with the most negative effects. This significant model was a simple and enriched method for managing and planning in basins that do not have enough data.The results of this model also showed that evaporative sediments in the basin, including the salt dome in the west of the basin, were the most important formations of water quality degradation. Also, the significant relationship between water quality parameters and low points of the basin or seasonal lakes indicated the leaching and transport of these sediments to these points by running water. These formations have shown the faces of mounds and hills in the region due to their weakness.Keywords: Water Quality, Geology, GWR, Izadkhast basin 5-References Jafari, M., & Tavili, A. (2013). Reclamation of Arid lands, Tehran, Tehran University press, 4, 396 p.Jehbez, O. (1994). Hydrochemical evaluation of Sarvestan basin with an emphasis on the role of geological formations, MSc in Hydrology, University of Shiraz, 436 p.Pratt, B., & Changa, H. (2012). Effects of land cover, topography, and built structure on seasonal water quality at multiple spatial scales, Journal of Hazardous Materials, 209–210, 48-58.
Geomorphology
Shahnaz Alizadeh; Mojtaba Yamani; Mohammad Reza sarvati; Manijeh Ghahroudi Tali
Abstract
Neglecting coastal erosion can lead to environmental hazards that are among the main factors affecting human communities and facilities. Paleontology researches demonstrate tens of meters fluctuation in water level of the Caspian Sea. The shores of the Caspian Sea have variable topography and land use ...
Read More
Neglecting coastal erosion can lead to environmental hazards that are among the main factors affecting human communities and facilities. Paleontology researches demonstrate tens of meters fluctuation in water level of the Caspian Sea. The shores of the Caspian Sea have variable topography and land use including lowlands (estuaries of rivers, gulfs and progradation) and sandy uplands. In this study, spatiotemporal analysis was used to analyze the changes in sandy coasts in relation to land use changes and the adaptation of the coastal line in the study area within the framework of coastal cells. Land use data for the years 1975 and 2020 were extracted using SAGA and ENVI software, and land use changes were analyzed using IDRISI software. The results showed that 68 kilometers of the coast have been unstable, with the majority of these areas experiencing erosion due to human activities (land use changes), including cells 10 and 3. Also, the erosion of unstable cells 5, 6, and 1 is of natural erosion type (sea level changes), and the erosion of unstable cells 9 and 2 is of natural-human erosion type. The remaining 24 kilometers of the studied coastline have been stable coasts, with the majority of coastal areas experiencing natural erosion (sea level changes), including cells 7 and 8. Cell 4 has had sustainable coasts with erosion of a natural-human type.
khadijeh Javan
Abstract
1-Introduction Climate change has been a very important issue in recent decades. Recently, frequent climatic events such as storms, floods, and droughts have been reported around the world (Habeeb et al., 2015). These extreme events will have devastating effects on ecosystems, society, and the economy ...
Read More
1-Introduction Climate change has been a very important issue in recent decades. Recently, frequent climatic events such as storms, floods, and droughts have been reported around the world (Habeeb et al., 2015). These extreme events will have devastating effects on ecosystems, society, and the economy (Hallegatte et al., 2013). Among these extreme events, drought plays a more prominent role due to its direct impact on socio-economic development and environmental degradation. Therefore, understanding drought phenomena is important for proper planning and management of water resources (Yilmaz, 2019). So far, various indicators have been proposed to monitor the drought. Undoubtedly the most well-known drought monitoring index is SPI proposed by McKee et al. The World Meteorological Organization has recommended this index as the main indicator of meteorological drought. It is also important to analyze the SPI trend, which provides scientific information for better modeling as well as the prediction of the phenomenon (Golian et al., 2015). A review of research conducted worldwide and in Iran shows that drought trend analysis has been mainly done using parametric tests such as linear regression and non-parametric tests like Mann-Kendall, Spearman, Sen’s estimator, and modified Mann-Kendall. These methods require a set of assumption validity such as serial correlation structure, probability distribution functions, and seasonal trends. For this reason, Şen (2012) proposed the Innovative Trend Analysis (ITA) method, which does not require any assumptions and analyzes the trend of time series based on a comparison of two ascendingly ordered halves. This method has found wide applications in hydro-climatic research and has been considered and used by many researchers. This study aimed to identify drought-prone areas in the Lake Urmia basin using SPI time series and the innovative trend analysis (ITA). For this purpose, SPI values in 12 and 24-month time scales were calculated based on 32-year-long precipitation data (1986-2017) in 8 synoptic stations in the Lake Urmia basin. Then the trend of the SPI series was investigated using the ITA method. Finally, the results of this method were compared with the results of the Mann-Kendall test. 2-Methodology 2.1. Standardized precipitation index (SPI) Among the quantitative indicators in drought analysis, SPI is acceptable as a suitable index for drought analysis due to the simplicity of calculations, the use of available rainfall data, and the ability to calculate for different time scales as well as different spatial scales. SPI can show the impact of drought on water resources. In a general classification, it is possible to use the 1 to 3-month SPI for meteorological drought, 3 to 6-month SPI for agricultural drought, and 12 to 24-month SPI for hydrological drought analyses and applications (Bonaccorso et al., 2003). 2.2. Innovative Trend Analysis (ITA) This method has been proposed by Şen (2012). In this index, time series are divided into two equal parts, which are separately sorted in ascending order. Then, the first and the second half of the time series are located on the x-axis and y-axis, respectively, of a Cartesian coordinate system. If the data are collected on the 1:1 straight line (45°), there is no trend in the time series (Fig. 1). If data are located on the upper triangular area of the ideal line, an increasing trend in the time series exists. If the data pile up in the lower (upper) triangular area of the 1:1 line, there is a decreasing (increasing) trend in the time series (Şen, 2014). Fig (1): ITA method The statistical significance test of the ITA method has been also proposed by Şen (2017). This test is performed based on the construction of confidence intervals and considering the difference between the two population means. If the slope value (s) is between the upper and lower confidence limits, the null hypothesis (H0) is confirmed; otherwise, the alternative hypothesis (H1) is accepted. The type of trend depends on the slope sign. The slope value can be positive or negative; this means that there is an increasing (+) or decreasing (-) trend in the time series (Şen, 2017). 2.3. Mann-Kendall test (MK) The non-parametric Mann-Kendall test is one of the most widely used methods for trend detection in time series. One of the main advantages of nonparametric methods is that the presence of outgoing data affects the result of the data process less than parametric methods. Besides, it is more suitable for data series having a short length and not normal statistical distribution or having missed data (Partal and Kahya, 2006). The positive and negative Z values indicate the increasing and decreasing trend in the series, respectively. 3-Results and Discussion To detect the drought trend in the stations of the Lake Urmia basin, the ITA method was used for the 12 and 24-month SPI series. All SPI series were divided into two 16-year sub-series: from 1986 to 2001, and from 2002 to 2017. To identify the possible trend of the drought as well as normal and wet conditions easily and better, two vertical lines have been added to the diagrams. The red line indicated the drought limit and the green line indicated the limitations of the wet conditions and the area between the two lines representing the normal conditions. According to the figures, the 1:1 line shows the neutral line (no trend) and in the case of no trend, the center point falls on the 1:1 line. The results of the trend analysis of 12-month SPI values showed that the drought and normal periods in Urmia, Saghez, and Mahabad had an increasing trend, but the wet conditions followed a decreasing trend. In Tabriz, an increasing trend was seen in normal and moderately drought periods, and a mild decreasing trend was seen in wet periods. In Takab, wet periods showed a sharp decreasing trend, and a slightly increasing trend could be seen in Sarab. In Sahand and Maragheh, there has been a declining trend in all SPI values, leading to more severe drought and weaker wet periods. The significance analysis of ITA and the Mann-Kendall test showed that in the 12-month SPI time series and based on the ITA method, all stations showed a significant trend, which was increasing in Tabriz and Sarab, and in other stations, it was decreasing. While the Man-Kendall method did not have a significant trend in Urmia, Tabriz, and Sarab, it showed a significant decreasing trend in other stations. In the trend analysis of 24-month SPI values by the ITA method, almost the same results were obtained. However, it should be noted that there was an increase in the slope of the trend for all stations. Another important point is that there were no significant increases in wet conditions. Similar to the results of 12-month SPI and based on two methods, the significance analysis of the ITA and Mann-Kendall test showed that Takab, Saqez, Sahand, Maragheh, and Mahabad had a significant decreasing trend and the difference was only observed in the higher ITA slope as well as the higher Z values in these stations. While in Urmia, Tabriz, and Sarab, there was no correspondence between the two methods. 4-Conclusions In this study, the ITA and Mann-Kendall trend tests were used for the 12 and 24-month SPI time series, determined for the 1970-2017 period, in order to demonstrate the hydrological drought trends in the Urmia Lake`s basin. The results of ITA and Mann-Kendall tests showed that Maragheh, Sahand, Saqez, Takab, and Mahabad had a significant decreasing trend in the 12 and 24-month SPI series. In Urmia, Tabriz, and Sarab, the Mann-Kendall test did not show any significant trends; while the ITA method showed significant decreasing and increasing trends in these stations. The results of this study can be used to manage water resources and understand the characteristics of climate change in the studied area.
Khodayar Zeiaei; abazar esmali; Raoof Mostafazadeh; Mohammad Golshan
Abstract
1-Introduction Watersheds are physical boundaries that include natural ecosystems and all human interactions. Land-use change in watersheds has been one of the major challenges in the 21st century. According to the findings of some researchers, the effects of land use on water resources are more severe ...
Read More
1-Introduction Watersheds are physical boundaries that include natural ecosystems and all human interactions. Land-use change in watersheds has been one of the major challenges in the 21st century. According to the findings of some researchers, the effects of land use on water resources are more severe than climate change. The estimation of streamflow in watersheds with different land uses is one of the important issues in hydrological studies. In recent years, one of the most widely used methods to facilitate computation has been the use of computer models that represent the watershed response with high accuracy. Restrictions on access to sufficient hydrological data make the role of watershed simulation models more important. This study aimed at modeling monthly runoff using the SWAT model and assessing the effects of different land-use change scenarios on runoff components. 2-Methodology The Ahl-e-Iman watershed with 7770.86 ha area is located in Ardabil province, which was selected to predict the effects of land-use change on hydrologic response. The SWAT model has been developed to simulate different parameters of the daily, monthly, and annual hydrologic responses. The curve number method in the SWAT model was used to estimate monthly surface runoff and output runoff yield. The main inputs of the SWAT model, including daily precipitation, minimum and maximum temperature, relative humidity, and wind speed, were obtained from available data centers to prepare a digital elevation map (DEM), land use map, and soil map. The SWAT CUP program was used to calibrate the model. The input of this program is observational flow data and the output file is the SWAT model. The statistical indices of Nash-Sutcliffe coefficient (NS), correlation coefficient (R2), and mean square error (MSE) were used to evaluate the simulation results of the model. 3-Results and Discussion Sensitivity analysis and the model calibration were performed in 2003-2010. The validation of the SWAT model showed that this model had a high performance for predicting the hydrologic effects of management scenarios in the Ahl Iman watershed. The results showed that the model had high performance in both periods. The obtained land-use map was given to the model to simulate the effect of land use change. The results of runoff simulation with both land uses of the study scenarios compared with the base flow are given in Figure 1. Figure (1): Comparing base flow with streamflow in the first and second land-use change scenarios 4-Conclusion The performance of the SWAT model was evaluated in both the calibration and validation periods; therefore, this model was used to investigate different land use management scenarios. The results of the first management scenario showed that the average streamflow discharge was equal to 0.3 cms, which showed 17% decrease in discharge compared to the base land use discharge (0.6 m3). The streamflow discharge increased 36% compared to the base flow in the second scenario. Therefore, this scenario will reduce the water resources of the region in a long time.
hydrogeology
Zahra Yunesian; fariba hemmati; Mohammad Mahdi Hossein Zade
Abstract
are connected at the end of the basin and form the Darbadam River. According to the results obtained for the central angle, in the first part between 2010 and 2021, the Meandri River pattern was developed and there was no change in the pattern class, but in the second and third parts in 2010, the river ...
Read More
are connected at the end of the basin and form the Darbadam River. According to the results obtained for the central angle, in the first part between 2010 and 2021, the Meandri River pattern was developed and there was no change in the pattern class, but in the second and third parts in 2010, the river pattern is not developed meandering, which in 2021 has become the developed meandering river patternBased on the average curvature coefficients in all three sections studied, the Darbadam River has a meandering pattern. Due to the characteristics of the region, such as the presence of resistant rock layers, the high slope of the region and also the mountainous topography, has led to low transverse displacement of meander in the region. However, in some parts of the river, due to human activities, including land use change, vegetation degradation and overgrazing, there has been a change in the river pattern.
water resources
vahideh abtahi; saeed jahanbakhsh; Hashem Rostamzadeh; hasan lashkari
Abstract
In global meteorological literature, atmospheric rivers are defined as long and narrow pathways of intense water vapor transport towards the polar regions in the middle latitudes, typically associated with low-level jet streams along the leading edge of extratropical cyclones. In this study, to identify ...
Read More
In global meteorological literature, atmospheric rivers are defined as long and narrow pathways of intense water vapor transport towards the polar regions in the middle latitudes, typically associated with low-level jet streams along the leading edge of extratropical cyclones. In this study, to identify the origins of the incoming atmospheric rivers to the study area, precipitation systems that occurred at more than half of the region's stations were selected. Then, using vertically integrated water vapor flux data from the east and north of the study area with a spatial resolution of 0.5 x 0.5 degrees, the magnitude of the water vapor flux was calculated. To calculate the magnitude of the flux, data including specific humidity and meridional and zonal winds at pressure levels from 1000 to 300 hPa were used. showed that these rivers have entered northwest and west of Iran from four moisture sources. The sources are the warm southern seas (the Sudan - Red Sea low-pressure pattern), the convergence zone region, the combined source of the Sudan low-pressure system and the Mediterranean circulation, and the Mediterranean Sea. Among these sources, the warm seas of Arabia and Oman and the Red Sea had the largest share in the incoming rivers to the region. These atmospheric rivers have been the strongest in terms of both temporal continuity and moisture flux. They first enter southwest Iran and then into the study area. The atmospheric rivers with the convergence zone source rank second in terms of their contribution to the region's precipitation.
