Davood Niknezhad; Mohammad Roghani; Abolfazh Nasseri; Jamshid Yarahmadi; Karim Mehrvarz; Mohammadebrahim Sadegzadeh
Abstract
Optimum application of precipitation, especially snow and rain, is very important, particularly in arid and semi-arid areas. Establishing rainwater harvesting systems with high runoff coefficient and therefore runoff storage can produce sustainable conditions to meet the water requirement of the plants ...
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Optimum application of precipitation, especially snow and rain, is very important, particularly in arid and semi-arid areas. Establishing rainwater harvesting systems with high runoff coefficient and therefore runoff storage can produce sustainable conditions to meet the water requirement of the plants and trees in dry seasons. For this purpose, three treatments including natural surface intact, covered with riprap and plastic cover with riprap were selected. The areas of each experimental plot were four m2 with square shapes and average slope of 11-18 percent were constructed. Results from 34 rainfall events showed that the amount of runoff from natural surfaces with riprap, intact natural surface and plastic cover with riprap treatments were 13, 20 and 57 percent of the amount of rainfall, respectively. The rainfall thresholds to initiate runoff in the treatments were 5.3, 4.7 and 2.6 mm, respectively. The highest runoff produced by plastic surface with riprap and this system is suggested as an appropriate option to collect rainwater in this study.
Puria Asiaban; Manoochehr Fathi Moghadam; Sajad Kiani; Ahmad Hosseini
Abstract
Rectangular orifices are considered as a common structure for discharge measurement in hydraulics. The purpose of the present research is to investigate the effect of the ratio of length to width of rectangular orifices with same surface area on discharge coefficient. Different rectangles are examined ...
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Rectangular orifices are considered as a common structure for discharge measurement in hydraulics. The purpose of the present research is to investigate the effect of the ratio of length to width of rectangular orifices with same surface area on discharge coefficient. Different rectangles are examined as orifice while the aspect ratio in one of them is equal to 1.618 (golden ratio). Golden ratio is a special number which can be frequently existed in nature and this study attempts to find the probable specialty of this ratio in hydraulics. So, the experiments were carried out on five rectangle orifices that the ratio of length to width of ones varied from 1 to 16. Also, a comparison between the discharge coefficient of rectangular and circular orifices is performed. Therefore, the number of 94 tests was conducted on the orifices in the discharge range of 0.136 - 0.637 L/s. A mathematical relation is developed as pressure distribution coefficient in order to account the effect of non-hydrostatic pressure distribution under low head condition. Results of the experiments showed that the increasing of aspect ratio generally leads to increase discharge coefficient so that discharge coefficient of orifices with variation of the ratio of length to width changes about 11.7%. Furthermore, it is illustrated that golden ratio doesn’t have any specialty in flow evacuation and the discharge coefficient of circular orifices is equal to minimum discharge coefficient of rectangular orifices.
Behrouz Mohseni; Hadi Razzaghian; Abdollah Darzi-Naftchali; Esmaeel Nikzad
Abstract
Runoff as one of the water balance components of a basin, is of great importance in watershed and water resources management. Suitable estimation of runoff is requires to determination of runoff coefficient. In this study, runoff coefficient was estimated for return periods of 25 and 50 years using rational, ...
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Runoff as one of the water balance components of a basin, is of great importance in watershed and water resources management. Suitable estimation of runoff is requires to determination of runoff coefficient. In this study, runoff coefficient was estimated for return periods of 25 and 50 years using rational, SCS and Cypress-Creek methods for basins up to 50 square kilometers. GIS software was used to overlay layers and basin analysis. Chow, s table was used to correspondence different methods. Due to the lack of compliance with Chow, s table and estimating lower runoff coefficients than reality in most of the study area, Rational Method did not provide suitable results. Cypress-Creek method was also effective in some basins due to it similarity with the SCS method. Average equivalent runoff coefficient of C25=0.37 and C50=0.41 demonstrated high accuracy of SCS method compared with two other methods. According to the soil conservation service method, minimum and maximum runoff coefficients of 25- year return period were related to Chalakrud 1 (0.06) and Safarood 4 (0.61) watersheds, respectively. Also, the minimum and maximum runoff coefficients of 50- year return were 0.1 (for Chalakrud 1) and 0.65 (for Safarood 4), respectively. According to the results of three methods, the lowest runoff coefficients were obtained for watersheds with the highest area and the lowest rainfall intensity.
Mitra Tanhapour; Mohammad Ebrahim Banihabib
Abstract
Prediction of the sediment load in water resources engineering projects such as flow diversion projects and dam construction is important factor for determining their service life. In this study, a model for estimation of daily sediment discharge was proposed using multilayer perceptron Artificial Neural ...
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Prediction of the sediment load in water resources engineering projects such as flow diversion projects and dam construction is important factor for determining their service life. In this study, a model for estimation of daily sediment discharge was proposed using multilayer perceptron Artificial Neural Network (ANN) model with back-propagation learning algorithm. For this purpose, current day’s discharge (Qt), precipitation, number of day in the year (DOY) and previous day’s discharge (Qt-1) data of Zoghal Bridge station (located on Chalus River) from 1990 to 2009 were used for training, verification and test. Results of testing different combinations of input data sets showed that effective parameters of the model performance are current discharge parameter, antecedent discharge, precipitation and DOY, respectively. This results has a relatively good agreement with standardized coefficients of regression model. Coefficient of determination (R2) and Root Mean Square Error (RMSE) were used to compare the different structures of ANN. Therefore, best network with 3-5-1 architecture and the amounts of R2=0.89 and RMSE=0.02 was obtained by elimination of DOY variable. The performance of ANN model in the prediction of sediment discharge was compared with Sediment Rating Curve (SRC) and Multiple Non-Linear Regression (MNLR) model. The results showed, in the training and test steps, SRC method and ANN model have the best performance, respectively. Furthermore, in the test step, the ANN model performed better results compared to two other methods by increasing R2 about 16%. Generally, the proposed ANN model can be estimated sediment discharge by less calculation time and cost and also with more accuracy.
Moien Jahanthigh; Ali Najafinejad; Mansour jahantigh; Mohsen Hosseinalizadeh
Abstract
Shortage of rainfall and drought are among the factors affecting the water shortage crisis in arid regions due to the high rate of evaporation in these areas, while reducing the amount of water productivity, it reduces soil moisture. Therefore, the application of conservation methods by reducing the ...
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Shortage of rainfall and drought are among the factors affecting the water shortage crisis in arid regions due to the high rate of evaporation in these areas, while reducing the amount of water productivity, it reduces soil moisture. Therefore, the application of conservation methods by reducing the rate of evaporation and maintaining soil moisture in addition to improving plant growth and yield increases water productivity. The aim of this study was investigation of the effect of sand mulch and nano-clay in buried clay pot irrigation on temperature and humidity changes in one of the wind erosion centers of Sistan region. For this purpose, wind sediments accumulated in Sistan plain as well as flood sediments of Helmand riverbed (sediments transported during floods entering from Afghanistan) were sampled. By determining the particle size of sediment samples, the largest particle size of wind sediments was separated to prepare a sandy cover using a sieve. To prepare clay nanoparticles, Flood sediments were also pulverized using ball mill by examining the particle size and determining the main elements (using the XRF method). By preparing treatments including sand cover, nano-clay and control by installing thermometers and probes at depths of 10, 30 and 50 cm Soil temperature and humidity were measured (using TDR) for a period of 186 days. Also, at the end of the test period to evaluate soil stability indices by sampling from different depths, the mean weight diameter (MWD) and geometric mean index (GMD) of aggregate diameter were measured based on dry sieving method. The results showed that there was significant different at 5% level on soil moisture and temperature distribution between treatments. In depth 10 cm, the highest amount of retained moisture were measured in sand mulch treatment (1.2 and 1.4 times retains moisture compared to nano-clay and witness treatments, respectively). The highest amount of retained moisture in depth 30 and 50 cm is related to nano-clay treatments (45 and 68% more maintain compared to sand mulch and witness treatments, respectively). The results also show that the highest and the lowest amount of soil temperature at different depths related to witness and sand mulch treatment respectively. Mulch cover by shaping temperature equilibrium in soil profiles, caused 17.2 and 33 % reduction of temperature compared to nano-clay and witness treatments. The results also showed that, there were significant differences between treatments in mean weight diameter (MWD) and geometric mean diameter (GMD) and the highest amounts of this index related to nano-clay treatment (p<0.05). Based on the results of this study, the use of sand mulch and nano-clay by reduces the temperature and improving the stability of aggregates, increases the volume of soil moisture in the subsurface layers by 30 to 45% and also increases the retention time in soil moisture and reduces irrigation frequency compared to the state without protective action in the soil. Therefore, the application of the methods used in this study, provides the required moisture to the plants to establish vegetation in the wind erosion centers of the study area.
Kourosh Shirani; Abdollah Seif; Mohamad Sharifikia
Abstract
Launching satellites with Synthetic Aperture Radar (SAR) sensors onboard, purposely built for differential interferometry (D-InSAR) applications opened new opportunities for mapping and monitoring slow ground deformations and even high speed landslides, for the updating of regional landslide inventories ...
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Launching satellites with Synthetic Aperture Radar (SAR) sensors onboard, purposely built for differential interferometry (D-InSAR) applications opened new opportunities for mapping and monitoring slow ground deformations and even high speed landslides, for the updating of regional landslide inventories as well as retrieving time series of landslide movements. The present work has been done by using DInSAR method, with objection of performance assessment of two radar sensors in order to detecting, monitoring and landslide inventory mapping in Dena Mountain of Zagros located in south of Isfahan province. For this purpose two sets of images including 17 and 21 RADAR images of PALSAR and ASAR sensors from ALOS and ENVISAT satellites were chosen and processed by D-InSAR method. The preliminary processing result showed that 16 interferometer images were suitable for the next processing stages from all applied data sets. The outcome of interfrogram analysis along with field checking showed that 914 segments are marked as landslides anomaly over the area of 13578 ha. The maximum land sliding activities was identified as 1.58 meter vertical displacement during May 2010 to September 2011. Furthermore, results showed differential interferometry method applied for above mentioned frequencies has sufficient accuracy and conform efficiency for landslide detection, monitoring and distribution mapping compared to other methods (field survey in extend area, aerial photo and optical satellite images). Out of this two frequency, low frequency of PALSAR images has better ability in landslide zonation due to its capabilities such as longer wavelength and reduced incoherency. Where the high frequency of ASAR images can offer more details of the landslides due to its shorter wavelength.
Mehdi Vafakhah; Mostafa Zabihi Silabi; Sedigheh Modarresi Tabatabaei; Hossein Sarvi Sadrabad; Arezoo Shafiei Bafti; Negin Ghaderi Dehkordi; Mohammadreza Riahi; Seid Saeid Ghiasi
Abstract
Extended abstractIntroductionInvestigating the climatic condition over watersheds has a decisive role in water resource management planning. Meanwhile, changes in temperature and precipitation have a great effect on the discharge of rivers, soil erosion, and fluctuations in the level of ground water, ...
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Extended abstractIntroductionInvestigating the climatic condition over watersheds has a decisive role in water resource management planning. Meanwhile, changes in temperature and precipitation have a great effect on the discharge of rivers, soil erosion, and fluctuations in the level of ground water, and the occurrence of floods. It is very necessary to carry out research related to climate change in order to prepare as much as possible to deal with the harmful costs caused by this change. The review of the studies conducted in Iran also shows that the scale of the study is in most cases at the local level and the study of the mean annual discharge trend and its magnitude has not been studied especially over Iran country. Therefore, the current research was planned with the aim of determining the mean annual discharge trend and magnitude over Iran. Materials and methodsIn the present study, the trend of mean annual discharge in Iran was determined by considering the effect of dams using Mann-Kendall and Sen’s slope methods. First, the statistics of all the hydrometric stations located in the Iran six major drainage watersheds were obtained from Iran Water Resources Management Company. Finally, 139 hydrometric stations with a statistical period of 17 to 65 years were selected in this study. The statistics of these stations were compared with the data available in nearby stations and suspicious values were also controlled. The homogeneity of the data and reconstructing the missing data was carried out using the run test and linear regression through the station with the highest correlation coefficient for each station with incomplete station, respectively. In the next step, non-parametric Mann-Kendall and Sen’s slope estimator tests were carried out within XLSTAT software in order to evaluate the trend and its magnitude analyses. After determining the trend of the study hydrometric stations, the spatial distribution map of the mean annual discharge trend in Iran six major drainage watersheds were prepared within Arc/GIS 10.2 software. Results and discussionThe results showed that 14 hydrometric stations were affected by the dam. However, in the hydrometric stations without dam, 84, six and 35 hydrometric stations have a decreasing trend (60%), an increasing trend (5%), and no trend at the 95% confidence level, respectively. Examining the trend of the time series of mean annual discharge in each of Iran six major drainage watersheds also showed that 80% of the study stations in the Persian Gulf and Oman Sea watershed have a decreasing trend, while no trend were detected in 20%, 10% and 9% of the total study stations in the Caspian Sea, the Central Plateau, and the Persian Gulf and Oman Sea watersheds, respectively as well as all the stations of the eastern watershed (Hammon). In the meantime, all study hydrometric stations in Urmia Lake and Sarakhs watersheds and 68% of the study hydrometric stations in the Caspian Sea watershed have a decreasing trend. ConclusionThe results obtained from this research showed that the decreasing trend was detected in most of the hydrometric stations (84 hydrometric stations). Therefore, the decreasing trend of hydrometric stations in Iran can be related to the decrease in rainfall, increase in temperature and the emergence of excruciating droughts caused by climate changes and also human interference, including the excessive increase in the construction of dams and the change of unprincipled land use. However, one of the limitations of the current research is not taking into account climate changes and land use changes and determining the contribution of each of the mentioned factors in the decreasing and increasing trend of the mentioned stations. The results of the present research can be very useful and important for water planners and politicians in order to manage water resources.
Aliakbar Jamali; Navab Raeesi
Abstract
By increasing in population, water resources become more important. Watershed Management today has an essential role in water supply in arid and semi-arid regions. Study area consists of a watershed with 6100 hectares areas situate in the northeastern of Nikshahr city named Matesang in the southeastern ...
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By increasing in population, water resources become more important. Watershed Management today has an essential role in water supply in arid and semi-arid regions. Study area consists of a watershed with 6100 hectares areas situate in the northeastern of Nikshahr city named Matesang in the southeastern of Iran. The survey data collected by a questionnaire, which its validity was examined by specialists such as professors, watershed and natural resource experts. Using SPSS, software reliability and Cronbach's alpha between 0.76 and 0.78 were obtained for different scales. In order to evaluate the economic impacts of watershed management projects based on benefit-cost ratio analysis and questionnaire method, the Chi-square test was used. The benefit cost ratio of 1.03 was obtained indicating the economic feasibility of the project. In order to assess the social-economic impacts of watershed management projects in the area questioners and Chi-square test was used. Chi-square test results showed, watershed projects had significant effect by reduction in immigration, flooding, unemployment, and success in flood and sediment control. Watershed management plans, were gained 100% participation satisfaction. The economic debate, results showed the significant reliability of soil and water conservation plans performance on increasing the amount of production, plant cover, the number of animals, water resources, the area of orchards and farmlands and reducing the area of uncultivated lands. In general, this research showed positive multipurpose aspects of mechanical soil and water conservation projects.
Jahangir Porhemmat
Abstract
The study aimed to evaluate the regional models in estimation of probable annual water yield in hydrologic units of Karkheh, Dez and Karun watersheds, located in south-west of Iran. Afterward, observational data of discharge and precipitation were used from 108 hydrometeric stations and 208 rain gauges. ...
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The study aimed to evaluate the regional models in estimation of probable annual water yield in hydrologic units of Karkheh, Dez and Karun watersheds, located in south-west of Iran. Afterward, observational data of discharge and precipitation were used from 108 hydrometeric stations and 208 rain gauges. Area, equivalent rectangle length, slope, Gravilios coefficient, precipitation, main stream length, main stream slope, mean watershed elevation, drainage density and perimeter were accounted in regional analysis. The cluster analysis and discriminate function was used in homogeneity analysis of hydrologic units. The results of multiple regression showed a high correlation between observed and computed data (0.98 and 0.99). It was also found out that annual discharge had a direct correlation with the first four above variables, and an inverse correlation with the other factors. The results showed that the annual yield can be precisely predicted by the area. Finally, the results showed that the annual depth of runoff yield over watershed had a high correlation with area and precipitation in a bi-variable regression model with regression coefficients of 0.52 to 0.8.
Fatemeh Zandi Dareh Gharibi; Zohreh Khorsandi Kouhanestani; Maliheh Mozayan; Nasim Arman
Abstract
Run off simulation is one of the most important topics in hydrology And its study is based on rainfall- run off models. Several rain fall and run off models have been developed and the most appropriate model should be selected for each catchment. By applying the appropriate model the water consumption ...
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Run off simulation is one of the most important topics in hydrology And its study is based on rainfall- run off models. Several rain fall and run off models have been developed and the most appropriate model should be selected for each catchment. By applying the appropriate model the water consumption will be optimized. The model should be selected for each catchment based on the model abilities and limits. In this study, the performance of two rain fall and runoff models, GR2M and GR4J were compared in Darehtakht Basin in Lorestan Province during 1379 to 1392. The Nash coefficient was used as a decision criteria for comparing two model performances. Nash coefficient for GR4J and GR2M were 42.7 and 65.5, respectively. Results showed that both models can predict the performance of the catchment accurately, but, based on Nash coefficient the GR2M is more accurate than the GR4M.
mohammad hedayatfard; Hamid Gholami; Seyed Masoud Soleimanpour; Arashk Holisaz
Abstract
Gully erosion is one of the most important phenomenons in land degradation and desertification, which upsets the balance of environmental resources and its sustainability. The aim of this study was to determine the effective factors on creation of gully erosion using data mining methods in Bayan Watershed ...
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Gully erosion is one of the most important phenomenons in land degradation and desertification, which upsets the balance of environmental resources and its sustainability. The aim of this study was to determine the effective factors on creation of gully erosion using data mining methods in Bayan Watershed in the north of Fars Province. K-Means clustering algorithms and CART decision tree were used to model gully erosion. The estimated accuracy based on the parameters affecting the creation area in the final model is 100% for the educational data set and 71.43% for the experimental data set. Results from measuring different variables from 40 selected gullies, including a target variable (creation area) and twelve predictive variables, like creation slope, vegetation, bare soil, surface gravel, surface litter, EC, pH, SAR, OM, clay, silt and sand in field and laboratory operations and the use of data mining techniques, showed that the creation of gullies in this watershed is a function of silt, acidity, bare soil, gravel and organic matter. These results showed the effect of vegetation and consequently, the presence of adequate organic matter in the soil as the most appropriate method for controlling gullies and the destructive and intensifying effect of bare lands without vegetation in intensifying gully erosion. Therefore, it is necessary to establish and establish permanent and compatible vegetation, to stabilize and improve soil structure and increase organic matter, and control and management programs, in lands with more silt, to be operated more carefully.
Leila Gholami
Abstract
In severely eroded areas, especially steep slopes, establishment of vegetation cover is not possible. The application of organic and inorganic amendments can therefore improve the conditions leading to establish vegetation cover through playing an effective role in runoff control. Accordingly, in the ...
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In severely eroded areas, especially steep slopes, establishment of vegetation cover is not possible. The application of organic and inorganic amendments can therefore improve the conditions leading to establish vegetation cover through playing an effective role in runoff control. Accordingly, in the present study, woodchips as a soil organic amendment was applied to control runoff variables including time to runoff, runoff volume and coefficient. For this purpose, three levels of woodchips treatment of 0.5, 1.0 and 1.5 kgm-2 were used in three replications at in 1 m2- plot scale. The plots were located in 30% slope in accordance with field conditions under simulated rainfall of 60 mmh-1 and duration of 15 min. The results showed that application of woodchips in 0.5, 1.0 and 1.5 kgm-2, time to runoff increased 97.50, 192.38 and 203.31%, respectively. The runoff volume decreased 35.23, 55.11 and 60.43% and runoff coefficient also decreased 42.43, 67.40 and 72.14% in three levels of woodchips treatments, respectively. The results of GLM showed that woodchips treatment had a significant increasing effect on time to runoff (p≤0.01) as well as a significant decreasing effect on runoff volume and coefficient (p≤0.05). The application of woodchips as a conservation treatment on the soil surface showed that this amendment can be used for runoff control especially where large quantities of woodchips are simply available.
Sajad Mirzayi; Majid Raoof
Abstract
Time parameters are adopted in most hydrological and hydraulic models. The most common known time parameter is time of concentration. The present study aimed to choose the best method for estimation of time of concentration in Atashgah Watershed in Ardebil Province. The values of times of concentration ...
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Time parameters are adopted in most hydrological and hydraulic models. The most common known time parameter is time of concentration. The present study aimed to choose the best method for estimation of time of concentration in Atashgah Watershed in Ardebil Province. The values of times of concentration in the present study were obtained by fourteen experimental relations and SCS method in WMS and HEC-Geo-HMS softwares. Mean weight of main channel’s slope and Manning’s roughness coefficient were measured by field operation. In order to evaluate efficiency of the method by using rainfall and hydrometry statistics, three flood events which were equal to rainfalls in terms of time were chosen and time of concentration was determined for these events by graphical method. Estimated and observed times of concentration (2.28 h) were evaluated by relative error percentage and remained mean error. Determination of the relations adopted in the present study indicated that area plays a pivotal role to estimate time of concentration properly. Evaluation of Hata-Vay relations, Kirpich, California, and Yen and Chow hydrographs showed that these methods do not consider area in order to estimate time of concentration; therefore, their estimations are considerably different from observed values. On the contrary, the estimations performed by Passini and Kerby relations were closer to observed values. Results revealed that adoption of more parameters would result in more acceptable results. So, total loss, land use, correction operation, hydrological status and soil hydrological group in addition to parameters as length and slope of the main channel are used to estimate time of concentration in SCS relation. HEC-GeoHMS and WMS models, which are used to estimate time of concentration by SCS method, adopt raster data, which cause higher accuracy compared to traditional methods such as manual method. It is concluded that in Atashgah Watershed, SCS method is suitable for estimation of time of concentration using WMS software with minimum values of remainder mean error values and relative error percentage being 0.05 h and 2.1%, respectively.
Reza Lagzian; Amir Sadoddin; Majid Ownegh; Akbar Alipoor
Abstract
One of the major issues that residential and industrial zones encountered is lack of stormwater management for these areas that can lead to inundation problem. This research aims to solve the problem of inundation as well as the shortage of water sources in Neyshabur City. Following the identification ...
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One of the major issues that residential and industrial zones encountered is lack of stormwater management for these areas that can lead to inundation problem. This research aims to solve the problem of inundation as well as the shortage of water sources in Neyshabur City. Following the identification of the executable stormwater management actions and developing 32 management scenarios for the city, the impacts of implementing the scenarios were predicted considering technical, environmental, hydrologic, economic and social criteria. The scenarios were prioritized using a multi-criteria decision making technique. The analysis based on the weighs elicited using the Delphi method among participants having tertiary education, indicates that scenario 24 (combination of bioretention, infiltration basin, and underground detention) is considered as the preferred scenario. But for the case of the participants under tertiary education, scenario 28 (combination of bioretention, infiltration trench, infiltration well, porous pavement, infiltration basin, and underground detention) is considered as the best scenario. The outcomes of the current research, explicitly assist the managers and planners in Neyshabur City to manage urban stormwater more effectively and can also implicitly provide suitable research model for other urban watersheds to be adopted by researchers and practitioners.
Hossein Emami; Ali Salajegh; Alireza Moghaddamnia; Shahram Khalighi; Abolhassan Fathbabadi
Abstract
Precipitation is of the most important inputs of runoff modeling. The availability of precipitation data with appropriate temporal and spatial accuracy is very important and necessary for watersheds with small and scattered rainfall stations. Nowadays, climatic satellites are practical and widely-used ...
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Precipitation is of the most important inputs of runoff modeling. The availability of precipitation data with appropriate temporal and spatial accuracy is very important and necessary for watersheds with small and scattered rainfall stations. Nowadays, climatic satellites are practical and widely-used tools in precipitation estimations. In this study, first the efficiency of TRMM satellite precipitation data in the monthly time series of Chehelchai Watershed was evaluated using R2, RMSE, NSE and Bias statistical indices by comparing the precipitation data of rain gauge stations (observed) and the values of these statistical indices were 0.54, 22.70, 0.44 and -14.86, respectively. Considering the value of the coefficient of determination (R2), it can be concluded that the TRMM satellite was able to estimate the 0.54 of observed precipitation. In the next step, three base data models including MLP, ANFIS and SVR were used to estimate the monthly runoff. Two different input scenarios were selected :1) observed precipitation data in t and t-1 time steps and runoff in t-1 time step and 2) satellite precipitation data in t and t-1 time steps and runoff in t-1 time step. To compare the accuracy and error of the models, R2 and RMSE of the validation stage were used. The ANFIS model with the values of R2 and RMSE were 0.80 and 0.97 for the first type input combination and 0.78 and 1.02 for the second type input combination, respectively, as the suitable single model for estimating runoff in the study area were selected. Then weighted-mean method was used in the data fusion approach to provide a data driven combination model for each combination of inputs into the model in the studied watershed. This data fusion approach data-driven model improved the values (R2=0.81) and (Bias=-4.85) for the first type input combination and also improved the value (R2=0.79) for the second type input combination.
Jahangir Porhemmat; Hadi Nazaripooya
Abstract
Infiltration is one the most important components of hydrologic cycle for utilization and managements of water resources. This phenomenon is affected by several factors and its measurement is difficult. Therefore, several models have been introduced for the simulation of infiltration. Previous studies ...
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Infiltration is one the most important components of hydrologic cycle for utilization and managements of water resources. This phenomenon is affected by several factors and its measurement is difficult. Therefore, several models have been introduced for the simulation of infiltration. Previous studies in evaluation of infiltration models show that each model can be preferred over others in a specific condition. Considering this fact, six infiltration models including Philip, Horton, Green-Ampt, SCS, Kostiakov and Luise-Kostiakov and thier parameters were evaluated. Gonbad catchment in Hamedan province was selected and it was divided into four homogenous hydrologic units. Then infiltration was measured during the dry season by double ring. The results showed that Philip model was the most accurate for estimating of the infiltration and Kostiakov model is also the second one. Regression coefficients of Philip model were betwean 0.975 to one, mean error -0.017 to +0.017 and the maximum root mean square error was 0.22. Regression coefficients of Kostiakov model were between 0.956 to 0.998, mean error -9.3 to +0.003 and the maximum root mean square error was 14.25. In addition, the correlation relations between parameters of these models and two soil texture indices were carried out. The findings show that except for SCS model, the other parameters correlate with these two indices in a 5% level and at least one parameter of each model has high correlation with them. Regression coefficient for A in Philip model, B in Green-Ampt, k in Horton, b in Kostiakov and b in Luise-Kostiakov were 0.99, 0.95, 0.99, 0.999 and 0.96 respectively. Results show a lower correlation between the other parameters and the percentage of clay and sand. Based on these results, it is suggested that the regression relations of models’ parameters for different conditions of soil texture and antecedent moisture in a variety of basins should be evaluated and determined.
Saeed Arab; Yasamin Segar; Mehdi Naderi khorasgani; Mohammad Asadi; Parvin Kia
Abstract
In a watershed, we can investigate the relationship between geomorphometric factors and sediment index. Digital Terrain Model (DTM) derived from DEM, has a high ability to receive, process, store, manage and monitor information for a catchment area. With the help of DTM in a watershed we can calculate ...
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In a watershed, we can investigate the relationship between geomorphometric factors and sediment index. Digital Terrain Model (DTM) derived from DEM, has a high ability to receive, process, store, manage and monitor information for a catchment area. With the help of DTM in a watershed we can calculate the sediment index (power stream, sediment transport and wetness) and some geomorphometric factors such as total length and slope along drainage, length and slope of straight drainage, drop coefficient, sinuosity and downstream elevation and its mapping. Bahadorbeyg Basin with an area of 216.69 km2 on northern pediment slopes of Alvand in Hamedan Province was selected for this study. First, the drainage rating was managed in DTM and the sediment index map along with the map of some geomorphometric factors (interpolation method) with four ranks and 30 focus points. Runoff and sediment discharge factors were proposed as a point estimator from the combination of sediment index with mean runoff and sediment discharge of the hydrometric station. In a complete regression model between sediment index (dependent variable) and some geomorphometric factors along with partial runoff and sediment discharge (independent variables), statistical relationships were significant at the level of 0.01 and 0.025. Results showed that the partial runoff and sediment discharge, the slope along drainage (total and direct), the drainage straight length, the downstream elevation and sinuosity are the most important factors affecting the sediment index, respectively. Finally, according to a time-series function (23 and 24 years old), the variation trend of runoff discharge had downward pattern in the basin and did not match with sediment discharge.
Vafa Homayounfar; Abdulvahed Khaledi Darvishan
Abstract
Laboratory plots and rainfall simulators are useful tools for erosion studies, but transferring soil and consequent preparation steps which leads to damage soil structure, are among the disadvantages of laboratorial soil erosion studies yet. In other words, soil preparation steps can cause considerable ...
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Laboratory plots and rainfall simulators are useful tools for erosion studies, but transferring soil and consequent preparation steps which leads to damage soil structure, are among the disadvantages of laboratorial soil erosion studies yet. In other words, soil preparation steps can cause considerable errors in the results of runoff and erosion in laboratorial conditions. On the other hand, measuring splash erosion, as the first ability to detach and move the soil particles, is very important in soil erosion studies. Knowing the uncertainties of splash results due to soil preparation methods is therefore essential to improve the accuracy of laboratory results. The present study has been therefore conducted to measure and compare the amount of splash in a sandy-clay-loam soil in both undisturbed and disturbed conditions in a hillslope in the southern part of Alborz Mountains under three rainfall intensities of 40, 60 and 80 mm h-1. The results showed that disturbing soil in erosion laboratory studies could significantly increase the upslope, downslope, gross splash (p<0.01) and net splash (p<0.05). The effects of soil disturbance on the ratio between upslope and downslope splash was not significant. According to the results, the increasing rates of upslope, downslope, gross and net splash due to soil disturbance were 216, 241, 234 and 257%, respectively.
Reza Talaei; Samad Shadfar
Abstract
Introduction
Landslides are one of the natural hazards in mountainous areas that threaten the safety of residents and the environment. In the past few decades, landslides have caused damage to natural and human resources in the Saqezchi Basin in the south of Ardabil Province. Landslides have occurred ...
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Introduction
Landslides are one of the natural hazards in mountainous areas that threaten the safety of residents and the environment. In the past few decades, landslides have caused damage to natural and human resources in the Saqezchi Basin in the south of Ardabil Province. Landslides have occurred in more than 9.2% (2600 ha) of the area. In this basin, like other landslide areas, for land-use planning and management, it is necessary to analyze the whole area in order to estimate the probability of landslides occurrence in the future. It is possible to solve this problem by analyzing the geomorphology, topography, geology, land use, hydrology and climate factors of the basin in the form of information layers in the geographic information systems on a regional scale. Landslide susceptibility assessment has not been done with modern methods and with high accuracy in the Saqzachai Basin until now. The results of this research can be used in predicting the possible occurrence of landslides and reducing damage in the Saqzachai Basin.
Materials and methods
The research basin with an area of 27,918 ha is located in the south of Ardabil Province and in the southwest of Khalkhal City. In this basin, the inventory map was generated based on 113 landslides, the training dataset and validation dataset were, respectively, prepared using 70% landslides and the remaining 30% landslides. Ten landslide causative factors based on slope angle, slope aspect, distance to faults, distance to stream network, distance to the roads, distance to settlement area, lithology, land-use, peak ground acceleration (PGA) and average annual precipitation were applied for the models analysis. Two nonlinear methods of neural network called multi-layer perceptron with feed forward structure and logistic regression were used to predicting the susceptibility of landslide occurrence. The probability of landslide occurrence in each pixel was calculated based on both models. The prediction accuracy of the two models were evaluated using the Receiver Operating Characteristic (ROC) curve.
Results and discussion
In the neural network model, landslides triggering factors, including the average annual precipitation (0.136) and the peak ground acceleration (0.134), have been the greatest effect in predicting the probability of landslides. The factors of slope angle (0.067), slope aspect (0.069), distance to faults (0.110), distance to stream network (0.101), distance to the roads (0.109), distance to settlement area (0.096), lithology (0.109) and land-use (0.068) are respectively important in landslides susceptibility modeling to using artificial neural networks. Therefore, all ten factors were used in modeling by artificial neural networks. The results indicated that the probability of landslide occurrence varies from 0.00 to 0.961. In the classification of the watershed according to the degree of landslide susceptibility by the natural breaks method based on the estimated probability by the neural network method, 85.7% of the area is placed in the zones with low and very low susceptibility. In 6.6% of the area, there is a probability of moderate susceptibility, and in 7.7%, there is a high and very high landslide susceptibility. Landslide susceptibility analysis is started without independent variable and ended by adding variables in the tenth step using logistic regression method. The results show that only three levels of the factor of slope aspect are ineffective in the logistic regression model. Probability values were calculated between 0 and 1 for all pixels in the area based on the values of independent variables by estimating constant and coefficients related to logistic regression model. The landslide-prone areas of low and very low susceptibility, medium susceptibility and high to extremely high-susceptibility grades are 79.9%, 10.1%, and 10%, of area, respectively, by the natural breaks method in the logistic regression model. The accuracy and validity of the logistic regression and artificial neural network models based on the ROC curve and the area under it (AUC) are equal to 0.848 and 0.929, respectively. The findings of the models show good results with the accuracy of two models being higher than 84%. The results obtained from two methods in most studies in the world and in Iran indicate their ability to accurately estimate susceptibility to landslides occurrence, but the artificial neural network method is more accurate despite its specific complexities.
Conclusion
Landslides are an important limitation for development in the landslide areas in the south of Ardabil Province. The environmental conditions in the Saqzachi Basin are susceptible to the occurrence of new landslides or the reactivation of old landslides. The probability of landslides occurrence was simulated using effective factors and using logistic regression and artificial neural network models in the region. The results obtained from the artificial neural network model are the most accurate and better than the logistic regression model. The landslides triggering factors, including the average annual precipitation and the peak ground acceleration have the greatest impact to predicting the probability of landslide occurrence using the artificial neural network model. The findings of the models show good results with the accuracy of two models being higher than 84%. The artificial neural network method is superior in explaining the relationship between landslide occurrence and influencing factors. The landslide susceptibility map was prepared using this method by dividing into five class, namely: very low (71.4%), low (14.3%), moderate (6.6%), high (4.3%) and very high (3.4%) susceptibility zones. Therefore, it is recommended to use the artificial neural network models in landslide susceptibility assessment in the basin and similar regions to help decision makers, planners, land use managers and government agencies in hazard and damage reduction.
Haji Karimi; Abed Zeidali; Reza Omidipour
Abstract
Knowing the effects of climatic factors on the farming plants is one of the most important factors on the increase or decrease of production and this subject has an important effect on the production especially in rainfed condition and specifically wheat as a strategic product. Successive droughts which ...
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Knowing the effects of climatic factors on the farming plants is one of the most important factors on the increase or decrease of production and this subject has an important effect on the production especially in rainfed condition and specifically wheat as a strategic product. Successive droughts which occurred in recent years are one of the climatic factors which affect the agricultural products. The aim of this research was to evaluate the wheat production in the drought conditions in rainfed lands of the Ilam Province. In this regard, the regression and Pearson tests were used to evaluate the effects of drought on wheat production. The results of correlation of drought frequency on decrease of wheat production in Dehloran, Ilam and Darreh-shahr townships showed as much as 45, 67 and 45 percent, respectively. Besides, the correlation coefficient indicated that the relationship of drought and wheat production in Mehran is 58, in Dehloran and Abdanan is 61, in Ilam is 46, in Aynan is 74, in Darreh-shahr is 63 and in Shirvan-Chardavol is 85 percent.
Ali Mohammad Ghaeminia
Abstract
One of the natural landscapes observed in arid and desert areas is the accumulation of loose sand in and around plants, which over time causes the formation of sand masses. In Arabic, this type of land is called “نَبکَة: /næbkæ/”, which means small hill and ridge. The word ...
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One of the natural landscapes observed in arid and desert areas is the accumulation of loose sand in and around plants, which over time causes the formation of sand masses. In Arabic, this type of land is called “نَبکَة: /næbkæ/”, which means small hill and ridge. The word has been translated from Arabic into English as well as Persian, and in most scientific texts in these two languages, the word “nebkha” and “نبکا /nebkɑ/” are used to express this form of land, respectively. Studying the scientific texts, it was found that there are other writing methods such as nabkha, nebka, nabka and nabkhah for this word, which with the images used to show this phenomenon, indicates that all the authors meant nebkha. These differences in spelling prevent researchers from accessing most of the research done on this phenomenon. In addition, terms such as coppice dune and phytogenic hillock are found in the equivalent of nebkha in the literature. In this short article, the use of the word nebkha in the texts as one of the landform of deserts has been studied. The results showed that in order to obtain more comprehensive information when studying this phenomenon from different aspects such as geomorphology and ecology, it is necessary to search for different writing methods and equivalent words.
Yaser Mehri; Jaber Soltani; Mojtaba Saneie; Mohammad Rostami
Abstract
A side weir is a structure which is set in a side of main channel and used for discharge of additional flow, diverting excess water and water level control of channels and in irrigation and drainage systems. Due to difficulties presented in mountainous regions, lateral ‘piano key weirs’ could ...
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A side weir is a structure which is set in a side of main channel and used for discharge of additional flow, diverting excess water and water level control of channels and in irrigation and drainage systems. Due to difficulties presented in mountainous regions, lateral ‘piano key weirs’ could be used in arc-shaped channels. In addition, curved channels, which are commonly used in mountainous areas, are places that can be used to locate the side piano key weirs. In this research, experimental investigation was performed on side piano key weirs type B, type c and sharp crest side weir on flow in the 30 degree curved channel. Among the findings of the above survey, one could point out to the equality of the specific energy on the two edges of piano key lateral weirs, the changes of which equal 0.277% for type C piano key lateral weir and 1.98% for type B weir. Also, focusing on the empirical analyses, it becomes evident that the coefficient of discharge for piano key weir bears a higher quantity considering the more effective length corresponding to rectangular weir. Comparing the coefficient of discharge of the two weir types C and B, it becomes evident that type B weir has a better functioning in relation to type C.
Hamidreza Masoumi; Alireza Habibi; Mohamadreza Gharibreza
Abstract
In recent years, flooding of rivers has resulted in destructive implications, especially in the coastal areas. Dashtyari coastal plain is located in the southeastern of Iran. The occurrence of destructive floods has led to extensive damage to agricultural facilities, buildings, and residents of the region ...
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In recent years, flooding of rivers has resulted in destructive implications, especially in the coastal areas. Dashtyari coastal plain is located in the southeastern of Iran. The occurrence of destructive floods has led to extensive damage to agricultural facilities, buildings, and residents of the region in recent years. Morphometric factors of the river and its surroundings land-uses and their changes in the future are effective and necessary factors in the planning of coastal plains. Remote sensing is an applicable tool to investigate the past, present, and postcondition of rivers. The GIS-Ready layers included satellite images (Landsat 5, 1987; 7, 2001; 8, 2019; Sentinel-2, 2020), and specific software (Envi 5.3, ArcGIS 10.4.1, and Idrisi TerrSet), as well as the existence and fieldwork documents, have been used to achieve the research aims. Probability values of land-use changes in 2019 were obtained based on Markov chains. Accordingly, the highest probability of changes 24.87% and 23.5% were obtained between the river and plain units, and between farms and river, respectively. Then, an automatic cell prediction map of 2019 is accomplished with the overall kappa coefficient of 95%. According to the accuracy of the output of the cellular Automata Markov model, forecasted Land use and river morphology maps for 2030 were developed. Further, possible changes in the river environment were obtained by fitting the two maps of 2019 and forecasting 2030. Moreover, bank erosion was identified in the 6 critical points along the Kajo, Dashtyari, and Bahu rivers. Finally, the destructive flood event in January 2020 in the Dashtyari region was investigated to match the results with natural events.
Mahsa Tashakori; Mehdi Hayatzadeh; Ali Fathzadeh; Javad Chezgi; Akram Bemani Kharanagh
Abstract
Introduction The most important problem in the development and construction of underground dams is the complexity of determining suitable areas for dam construction. This problem arises from the fact that many criteria and factors including social, economic, geological and hydrological criteria are involved ...
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Introduction The most important problem in the development and construction of underground dams is the complexity of determining suitable areas for dam construction. This problem arises from the fact that many criteria and factors including social, economic, geological and hydrological criteria are involved in its proper location. Therefore, it is important to use methods that can determine suitable places for the construction of underground dams with high accuracy and with the least amount of time and cost. The construction of an underground dam is recommended as one of the solutions for water supply in arid areas where there is no access to usual sources, such as wells and permanent rivers, or they have few water resources. For this purpose, in the present study, the location of the prone areas for the construction of such dams has been investigated. The studied area is the Rodan Watershed in Hormozgan Province, which has a good potential for the construction of an underground dam due to its dry climate and special geological conditions.Materials and methodsIn this study, the number of eight initial locations were identified as potential points for construction underground dam by combining digital elevation model, topographic features, geological and hydrological features in GIS. In the following, after forming the decision matrix using Vicor model, ranking, determining the index and selecting the smallest index as the best option were done. Finally, the options were sorted based on the values of desirability index, dissatisfaction index and Vicor index. Then, the best option that has the smallest Vicor index was selected.Results and discussionAccording to the obtained results, the value of Vikor index (Q) was 0.0158 and 0.097 for sites 5 and 2, respectively, and that way, based on Vikor index, the first rank belonged to the site 5 and the second rank belonged to the site 2. Therefore, out of the initial eight locations, only two places were suitable spots and other suitable sites were rejected due to the distance from the centers of population concentration and agriculture. Rank one, located in the east of Ziarat Ali, is one of the best places to build an underground dam due to the hydrological and topographical conditions, including the fact that the slope in this site is less than five percent. The second priority, located in the north of Brentin district, was considered as a suitable option for the construction of an underground dam due to its location in the vicinity of a sparsely populated village where drinking water is supplied through a well. Among the criteria used in the present research, the criteria of water need, distance from the village, pH and EC parameters, and water quantity were the most important in the sites that have been assigned the first and second priority.Conclusion Examining the results of the reservoir surface factor in this research showed that the larger the reservoir surface, the higher the priority in locating this structure. In underground dams, unlike surface dams where the large reservoir surface is considered a disadvantage due to losses by evaporation, regardless of other factors, the best place to build an underground dam in a river is the canyons that have the maximum area of the reservoir in upstream. Looking at the axes selected in the current research, it can be seen that the highest priorities and the most valuable axes are selected in the quaternary formations, which can indicate the accuracy of the structure's positioning. Since the peak of water consumption in the region is in the spring and summer seasons, therefore, by constructing an underground dam in the proposed sites, part of the water shortage and crisis in the hot seasons can be compensated.
Saeed Sarkamaryan; Mehdi ghomeshi
Abstract
As a method for dimension reduction and elimination of energy damper structures that are located downstream of rapids, obstacles that are put on rapids are sometimes employed. In this research, damping capabilities of floating cubic obstacles were investigated using an experimental model. To do this, ...
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As a method for dimension reduction and elimination of energy damper structures that are located downstream of rapids, obstacles that are put on rapids are sometimes employed. In this research, damping capabilities of floating cubic obstacles were investigated using an experimental model. To do this, various experiments were performed on four different slopes of rapids with and without obstacles in a laboratory open channel in the hydraulic laboratory of Shahid Chamran University of Ahvaz. Results of the experiments without obstacles on discharges contained in this research’s scope showed that the amount of damped energy relative to the upstream energy ranges from 10 percent for a slope of 1:4 to 63 percent for a slope of 1:5. According to comparison of energy loss in different slopes, we can conclude that the reduction of chute bed slope increases the relative damped energy. We can also argue that the reduced chute bed slope leads to a slower energy loss procedure. Energy dissipation had an increase of 17 to 44 percent according to the studied results of models with and without obstacles. According to comparison of energy loss in different slopes of models with obstacles, we can conclude that the amount of relative damped energy increases and the damped energy reduction occurs on lower slope by reducing the chute bed slope. Using multi-variable regression, some equations were extracted in the final section in order to predict energy damping in such rapids with or without obstacles.
