Zabihollah Eskandari; Fathollah Ghayour; Amir Hossein Sherbaf
Abstract
Water deficiency in arid regions especially in Iran, generally reduces the cultivation and considered as a major limitation in green cover re-establishment process in deserted areas. This study aims to overcome on drought and to achieve a strategic way of increasing the water use efficiency and reduction ...
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Water deficiency in arid regions especially in Iran, generally reduces the cultivation and considered as a major limitation in green cover re-establishment process in deserted areas. This study aims to overcome on drought and to achieve a strategic way of increasing the water use efficiency and reduction of costs. This study is carried out in a wind-eroded part of Aran and Bidgol county of Isfahan province, Iran and two species of Haloxylon and Nitraria sp were cultivated in treated and check soils in mentioned area. The treatments were adding five of two kinds of polymer water absorbent to the soil of root environment. The check samples were irrigated every 14 days once and the treated ones every 14, 28, 35 and 42 days once. During two years of study, the moisture of root environment was measured in all samples. In third year the amount of live seedlings were also accounted. The statistical analysis showed that there is a significant difference between the treated and check samples in all irrigation periods in significance level of 5%. In other words, increasing of irrigation period in treated samples compared with check treatment hold more moisture in root environment. Mean comparison between treatments showed no differences in volumetric moisture of 21 compared with 28 and 28 compared with 42 irrigation periods. And also there was no difference between two absorbent in all treatments. The increasing rate of live seedlings, after 3 years, between treated and check samples represents that the polymers give a good establishing circumstance to young seedlings. In other words it is resulted that these water absorbents are capable of reducing the moisture stress in root area of irrigation periods and increase the rate of established seedlings. We assume that Aquasorb polymers and TC are successfully increasing the water holding capacity of soils in green cover re-establishing activities of deserted areas. With increasing the water holding capacity they also reduce also the costs by 50-70 percent.
Masoumeh Bahri; Mohammadtaghi Dastorani; Masoud Goodarzi
Abstract
Studies of climate change and its impacts on the frequency and intensity of future droughts can help programming for the management of water resource and adaptation of the destructive effects of this phenomenon. The aim of this research is trying to assess the climate change in 2011-2030 period and its ...
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Studies of climate change and its impacts on the frequency and intensity of future droughts can help programming for the management of water resource and adaptation of the destructive effects of this phenomenon. The aim of this research is trying to assess the climate change in 2011-2030 period and its impact on drought in Eskandari Basin. To achieve this purpose, after validating Lars-WG to generate weather parameters, HadCM3 output downscaled under A2 and B1 scenarios. Next, minimum and maximum temperature and precipitation was predicted. Also, SPI index was calculated. Underlying these scenarios minimum temperature growth dramatically in March, June, July and September 0.3 to 1.6 °C. Additionally, highest and lowest increment in maximum temperature will occur about 0.02 and 1.6 in May and April, respectively. However, the results indicated an increase of 7.2 to 10.9 percent in the average of annual precipitation, but due to the fact that there is no any increase in the number of wet days, extreme rainfall intensity will soar remarkably. Substantial reduction in precipitation belongs to May and April. Regarding this issue, this shortage will affect with several months lag and the most severe agricultural drought will occur in August and hydrological drought will fall out in December based on six and 12 months SPI, respectively. Annual analysis showed that 75 percent of the years are in normal condition. Therefore, in Eskandari Basin, increasing drought frequency will not be expected in 2020s. But, precipitation oriented towards warm seasons.
Reza Sokouti Oskooei; Mohammad Hossein Mahdian; Shahla Mahmoodi; Mohammad Hasan Masihabadi
Volume 2, Issue 3 , October 2010, , Pages 161-169
Abstract
Planning and suitable management is necessary for optimal use of soil and for this; spatial variability of soil characteristics is important which may be edcarried out through geostatistical methods of parametric and non-parametric predictors such as TPSS, WMA, Kriging and Co-kriging. This research work ...
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Planning and suitable management is necessary for optimal use of soil and for this; spatial variability of soil characteristics is important which may be edcarried out through geostatistical methods of parametric and non-parametric predictors such as TPSS, WMA, Kriging and Co-kriging. This research work was done in Southern part of Uromieh plain with 36690 ha surface area in order to study the spatial variability of soil lime, sand and saturation moisture percentage. Distance between soil profiles ranged 1300 to 4700 meters. For estimation and prediction of them in non-sampled points, the Kriging, Co- kriging and Weighted Moving Average were used in Geographic Information System environment. For selecting suitable interpolation method, Cross validation and MAE and MBE parameters were used. Selected method was also used for estimating and mapping of the selected soil characteristics. The Sturges rule was used for defining map classification. Results showed that the Kriging method has the highest accuracy with correlation coefficient of 0.83 and error of 3.98 percent for prediction of soil characteristics in non-sampled points.
Parviz Abdinezhad; Parviz Moradi
Abstract
In this research, some effective factors on stability and sedimentation of woven-wire check dams within marly areas were studied. For this pupose, data of 380 light-weight metallic dams were collected during field study and Pearson correlation coefficients and regression analysis of variance of SPSS ...
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In this research, some effective factors on stability and sedimentation of woven-wire check dams within marly areas were studied. For this pupose, data of 380 light-weight metallic dams were collected during field study and Pearson correlation coefficients and regression analysis of variance of SPSS statistical software were used in analysis procedures. The results showed that there were significant relation between width, length and volume of dams with stability at confidence level of 99% and according to correlation coefficients, width of dam showed a higher correlation in comparison to two other variables, but length of dam holds the second place. On this respect, dimensions of dams were among the effective factors on their stability. The stability of dams also represents an inversely linear relationship (correlation coefficient of 0.24) with volume of sediment accumulated behind them. The link between length and width to volume of accumulated sediment favors a direct linear relationship, and based on their correlation coefficients (0.69 and 0.23 respectively) the impact of length of dams is greater. In general, to reach a desired stability of these dams, their dimension must be in accordance with standards and must be determined using respective equations.
Mohammad Shabani
Abstract
Rainfall erosivity is one of the effective factors on rainfall erosion which is very important in water erosion. Preparing rainfall erosivity mapping is an important issue in soil conservation, erosion control and land management. The objective of this research is evaluation of geostatistical methods ...
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Rainfall erosivity is one of the effective factors on rainfall erosion which is very important in water erosion. Preparing rainfall erosivity mapping is an important issue in soil conservation, erosion control and land management. The objective of this research is evaluation of geostatistical methods for rainfall erosivity mapping in Fars province. First, 92 meteorological stations having at least 20 years data and relevant distribution over the region were selected and the modified Fournier index was calculated for each station. Then several interpolation methods including Ordinary Kriging (OK), Simple Kriging (SP) and deterministic methods such as Inverse Distance Weights (IDW), Radial Basis Function (RBF), Local Polynomial Interpolation (LPI) and Global Polynomial Interpolation (GPI) were used in order to extend point data to spatial information in the process of preparing rainfall erosivity map. The evaluation of the results based on higher R value and lower MAE and RMSE values showed that among the studied methods, the OK method has higher R value and lower RMSE and MAE values (R=0.87, MAE=13.09, RMSE=18.52), then it was selected as the most appropriate method for rainfall erosivity mapping in Fars province. Also the results revealed that 0.24% of the province has negligible erosivity, 27.06% has low erosivity, 43.62% has moderate erosivity, 14.48 have high erosivity and 14.6% has very high erosivity.
Manouchehr Amiri; Hadi Nazari pouya; Hamid Reza Peyrovan
Volume 1, Issue 3 , October 2009, , Pages 179-188
Abstract
The marl soil types are very sensitive to erosion and are deposited into reservoirs of dams and areas of flood spreading in form of considerable sediment annually. This process increases the expenses of filtration of drinkable water and pre-filtration of water of artificial recharge severely. So the ...
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The marl soil types are very sensitive to erosion and are deposited into reservoirs of dams and areas of flood spreading in form of considerable sediment annually. This process increases the expenses of filtration of drinkable water and pre-filtration of water of artificial recharge severely. So the investigation of marl soil types from different aspects is very important for experts and researchers. In this research, it was tried to recognize the effective variables on erosion rate of marls in Hamedan province. 49 samples of 41 spots in 3 marl areas were taken to determine the physical and chemical properties. The characteristics of place of sampling like; slope, geographical situation and privilege of 7 parameters for surface factor of soil were noted. Also, the test of simulated rain was done by the Kamphorst΄s rainfall simulator apparatus in the 41 above spots and 41 samples of runoff were taken and the amount of soil lost were measured and calculated by simple method in the laboratory. The amounts of 23 physical and 15 chemical variables were determined. Then, all data were evaluated by Kolmogorov-Smirnov test and the abnormal data were normalized by logarithm and were evaluated by correlation, bi-variate and multivariate regression tests. The results showed that only 9 variables have significant and linear relation with soil loss, where plastic index, clay percent and clay ratio are the most important variables for evaluation of marl soil loss at marls of investigated areas respectively.
Touraj Sabzevari; Mehdi Mokhberi; Sadegh Hosseini khotbehsara
Abstract
Catchments consist of a series of sloping pervious overland whose surface and subsurface runoffs are transmitted to their outlet through stream networks. In the catchments with high perviousness and good vegetation cover, the amount of subsurface gains more significance and it might have a considerable ...
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Catchments consist of a series of sloping pervious overland whose surface and subsurface runoffs are transmitted to their outlet through stream networks. In the catchments with high perviousness and good vegetation cover, the amount of subsurface gains more significance and it might have a considerable share in the direct runoff. In this study, a hydrologic rainfall simulator model with the length of 1.92 meter and width of one meter and depth of 0.35 meter has been used which its surface and subsurface amount of flow have been measured by means of two different weirs. The texture of soil in Estahban Watershed was loamy sand. The experiments were conducted under three slope angles of 0.1, 3, 6 and 9 degrees and under rainfall intensity of 31.73, 47.6 and 63.46 millimeter per hours. Based on the results, the slope changes from 0.1 to 3 degrees resulted in 50 percent decrease in the subsurface flow and 10 to 15 percent increase in the surface flow in different rainfalls, but, from the slope of 3 to 9 degrees, no significant change was observed in the two flows and in the slope change from 6 to 9 percent of subsurface flow and 2 percent of surface flow, there was surface flow observed. The increase in rainfall intensity causes rise in hydrograph amount of surface and subsurface flow. The proportion of surface to subsurface flow changed on average between 7.5 and 14.5 times the subsurface flow under three rainfalls for the loamy sand. With the increase in slope, the surface flow amount increases and infiltration decreases. In this study, two non-linear regression equations were presented for measuring surface and subsurface peaks which is a function of length, slope and rainfall intensity of the slope.
Nadergholi Ebrahimi; Azim Shirdeli; Ebrahim Nikkhah Javan; Majid Hosseini
Abstract
The riverbed and margin vegetation causes to increase in roughness against flow, decrease in average flow velocity, reduce water-energy, and alterations in layer velocity distribution (the flow velocity profile) across the river. In current experimental research, the effect of branching vegetation on ...
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The riverbed and margin vegetation causes to increase in roughness against flow, decrease in average flow velocity, reduce water-energy, and alterations in layer velocity distribution (the flow velocity profile) across the river. In current experimental research, the effect of branching vegetation on the stream flow and bed formation is analyzed. The flow conditions are examined in experimental channel with 7 meter length, 25 cm width and height through different flow rates (3,5,7 lit/s) and slopes under different(0.001, 0.003, 0.005) and densities of vegetation (50, 25 and 12 percent). According to the processed data, it can be implicated that the difference between flow level, substrate, and rate is affected by the types of vegetation density; thereby existence of vegetation causes resistance to flow and depth increment. In all experiments, through the vegetation density increment, the bed erosion increases compared with the primary condition in which the most and least alterations are observed in 50 and 12-percent density, respectively. In the condition of equal flow rate with density increment, the flow depth is increased. The bed particle displacement in the section covered by vegetation is increased through density increment in which flow level in 50 is more than 25 and 12-percent density, as well as, flow substrate erosion and alteration whereas sediment (particles accumulation) is appeared frequently under less density at the end of section covered by vegetation.
Niayesh Fendereski; Mohsen Masoudian; Klaus Röttcher
Abstract
Over the last two decades, the need to restore rivers to the natural and near-natural state has become noticeable. One of the most important tools to achieve this goal, is to assess the hydromorphological changes of the river due to human intervention. In the present study, in order to evaluate the hydromorphological ...
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Over the last two decades, the need to restore rivers to the natural and near-natural state has become noticeable. One of the most important tools to achieve this goal, is to assess the hydromorphological changes of the river due to human intervention. In the present study, in order to evaluate the hydromorphological conditions of the Tajan River along the middle to lower parts (city of Sari) the Morphological Quality Index (MQI) and Hydromorphological Quality Index (HMQI) has been used. Seven reaches in 50 m riparian buffer width were selected and three quality main indicators including geomorphological, artificial, and channel adjustment were studied using satellite images of Landsat 4 in 1975 and Landsat 8 in 2019, aerial photos in 1960 and 2006, hydrological data, and data collected during the field surveys. The results showed that the studied reaches of Tajan River mainly classified as the moderate-quality class for the MQI, while it is classified as one quality class lower for HMQI, mainly as the poor-quality class. The main reason is that all the studied reaches (except reaches 1 and 7), located downstream of the Shahid Rajaee Dam, within the 30 km, which change considerably the river discharge and sediment transfer, also the extreme human impact and anthropogenic stresses in the catchment, such as land-use change. The results also showed that the method, which was used in this study, is effective, in general, index-based assessment, diagnosis of the hydromorphological problems, and an exact comprehensive realization of the response to the mentioned stresses.
Shahram Roustaei; Mahasa Roustaei; Mohamad Sharifikia; Jamshid Yarahmadi
Abstract
Differential synthetic aperture radar interferometry (D-InSAR) has become a useful technique for monitoring ground movement. The technique enables the analysis of very small ground movements in continuous and large areas and has the advantages of high accuracy, high resolution, all-weather adaptability, ...
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Differential synthetic aperture radar interferometry (D-InSAR) has become a useful technique for monitoring ground movement. The technique enables the analysis of very small ground movements in continuous and large areas and has the advantages of high accuracy, high resolution, all-weather adaptability, low cost and inaccessible area coverage. Thus, D-InSAR has been widely used for investigation of geologic hazards, such as subsidence, landslide, earthquake, and volcanic activity. In this research, D-InSAR technique was applied for detection of unstable slopes and determining moving displacement rate. For this purpose, eight SAR images of PALSAR sensor of ALOS satellite were selected for processing based on D-InSAR approach. Obtained results were validated by field observations prates. This paper is only represented results related to image pair processing of 5th July to 5th October 2007 with 92 days interval. Garm Chay watershed with 940 km2 area is located in North Eastern and 40 km far from Miyaneh in Eastern Azerbyjan, Iran. This region with 380 landslides is considered as one of the unstable landslide proven area in Eastern Azerbyjan. Occurrence of these slides caused heavy damages to rural properties and arable lands. As a result, Sovin village in north western part of this watershed was moved to other safesite. The results clearly showed that some old stabilized landslides were still active. Because of their proximity to local stream networks (check the possibility for stream displacement), they can be considered as important sources of sediment yield. Before mentioned period, the maximum displacement was calculated 5.8 cm in landslide surface near to Avin, Atajan and Benavaran villages. The results from this method should be validated by geodetic methods and field obsevations.
Ali Reza Masjedi; Abdol Rasoul Telvari; Hasan Kazemi
Abstract
Determination of the erosion depth at the base of the bridge requires knowledge of how to move the river bed sediments. The base of bridge disrupts the normal flow of the river, so turbulence and disturbance resulting in erosion of sediments surrounding the base. The hole created around the base depends ...
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Determination of the erosion depth at the base of the bridge requires knowledge of how to move the river bed sediments. The base of bridge disrupts the normal flow of the river, so turbulence and disturbance resulting in erosion of sediments surrounding the base. The hole created around the base depends on the shape and geometric properties. Moreover, ingredients of river bed and also flow hydraulic conditions such as flood conditions and dune cross can effect on depth of the hole. Since, development of erosion hole hazards the structural stability of the bridge. So predict for amount of hole and necessary measures to suppression are considered as common engineering practices in river engineering. For investigation of basic geometry of the bridge on control scouring around the river bend an experiment in a laboratory flume was done with a 180-degree bend, 2.8 m for central radius, 0.6 m wide and R/B= 4.67 under the walls made of Plax glass. In this study, clear-water scour around the base were studied by putting a basic cylinder with 6 cm diameter, foursquare section, semicircle tip with 6 cm width and 18 cm length in flume at positions 30, 60 and 90 degrees, with rates of 24, 28, 30 and 32 liters per second and a constant depth of 12 cm. For flooring of flume a natural sand by uniform gradation with D50=2 mm and uniformity coefficient of 1.3 were used. The results of this experiment showed that the maximum scour depth during placing the base with cylindrical section and foursquare section with the semicircle tip were alternative during the bend length and in the first half of the bend and at the position of 60 degrees had the maximum scour at the base. Also, scouring in all cases was lower for base with cylindrical section as compared to foursquare section with semicircle tip. In all conditions, increasing of flow have been increased the scour depth.
Behzad Raighani; Said Soltani Koopani; Seyed Jamaleddin Khajeddin; Sousan Barati
Volume 2, Issue 4 , January 2011, , Pages 221-236
Abstract
Snow-cover and its equivalent water, supply 1/3 of the water requirements for farming and land irrigation throughout the world. Therefore, water contents estimation of a snow-cover or estimation of snowmelt runoff is necessary for hydrologists. Several snowmelt-forecasting models have been suggested ...
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Snow-cover and its equivalent water, supply 1/3 of the water requirements for farming and land irrigation throughout the world. Therefore, water contents estimation of a snow-cover or estimation of snowmelt runoff is necessary for hydrologists. Several snowmelt-forecasting models have been suggested which most of them require continuous monitoring of snow-cover. The most efficient means of monitoring snow-cover patches are remote monitoring through satellites imagery. In this research, snowmelt runoff forecasted in a new scheme, using maximum and mean daily temperatures, two snowmelt measuring device and MODIS data. According to the outcome results, one can map snow-covered area with sufficient precision using MODIS data, while the map is useful for related calculations about snow patches. We calculated, after studying the satellite images, the snow-cover changes predicted in a new way for the periods that the MODIS data was not available. Maps were produced and with control of ground truthing their very high precisions confirmed. The melted water resulted from temperature changes were modeled as equations, which, their calculated amounts are comparable to the ground truthing points very well. With regards of water flow changes, equations calculated to estimate the daily melted water flow. These equations are comparable to the ground truthing points as well.
Farzad Bayat Movahhed; Davood Nikkami; Mohammad Tokasi; Parviz Moradi; Hamideh Daghigh
Abstract
In arid and semi-arid regions the precipitation occurs erratically, and often, with high intensity which causes sediment production and soil loss especially in the areas ploughed parallel to the hill slope direction. In such areas, we can reduce those undesirable effects through employing proper management ...
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In arid and semi-arid regions the precipitation occurs erratically, and often, with high intensity which causes sediment production and soil loss especially in the areas ploughed parallel to the hill slope direction. In such areas, we can reduce those undesirable effects through employing proper management method. In this survey the effect of two treatments of applying straw mulch in standard plots and over three slope classes of 0-12, 12-20, and 20-40 % with three replicates in the split plot format on the base of RCB design were compared. In all plots, the parallel plough to slope direction was done. After wheat cultivation, on the half of plots, straw mulch was applied uniformly by hand on the soil surface. After any rainfall events, the amount of sediment was measured. Results showed that application of straw mulch caused a reduction of about 36.9, 10.8, and 55.4 % soil loss in three slope classes compared to the plots without mulch application respectively. These amounts for organic carbon loss were 33.2, 7.1, and 29.43 %. Statistical analysis by SAS software showed that difference between two treatments for sediment and Organic Carbon was significant at 5% probability. These results show that straw mulch application can highly increase the infiltration and water absorption and reduce soil and O.C. loss. Also, it can prevent the reduction of soil fertility through reducing organic material loss.
Ramtin Sobhkhiz Foumani; Alireza Mardookhpour; Mohammadreza Fallah Ghavidel
Abstract
Extended abstractIntroductionToday, the estimation of the rainfall resulting from rainfall, especially in small basins with no statistics, is one of the main activities among hydrologists, and the estimation of the volume of runoff resulting from rainfall and the application of surface water collection ...
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Extended abstractIntroductionToday, the estimation of the rainfall resulting from rainfall, especially in small basins with no statistics, is one of the main activities among hydrologists, and the estimation of the volume of runoff resulting from rainfall and the application of surface water collection and containment methods, both in terms of water supply And it is very important in terms of flood prevention. In this research, by using the simulation of the conversion of rainfall to floods in a long statistical period of about 20 years between January 23, 2000 and September 23, 2021 in the Astana-Kochsafhan catchment area with HEC-HMS software, one of the main objectives of the selection effect The type of flow conversion hydrographs was checked on the amount of calculation error of the closed boundary flood. The main goal of this research was to investigate the importance of the dimensionless Muskingum coefficients in developing a flood distribution model in a computer simulator. Materials and methodsFor do this research, two types of models were used in extracting the flow hydrograph. The first model continued by using the integration of the general set of sub-basins until the stage where only 5 general sub-basins or 4 sub-basins in the upstream of the catchment area leading to the outlet of the range continued. The process of removing the sub-basins was done by combining the area and other physiographic parameters in the geographic information system environment and using the HEC_GeoHMS extension. Results and discussionIn addition to the principle of trending, by analyzing the results, it was found that each of the surface current conversion methods under known and more widely used titles have limitations, weaknesses and strengths that can be The title of local regressions was also considered for this transformation, the SCS method as the most well-known method, due to its lower limitation in models with local conventional scale in the limits of third-order watersheds, showed that the error of the obtained data It has been less than other cases. This amount of error was predictable in itself. Clark's method, which has a more structured approach, like Schneider's calculation method, calculates the error in its general form, as well as in the maximum values, moment of occurrence, volume, etc. slow In particular, Schneider's method is designed for large domains in its default. In this study, unlike the SCS method, in which the Nash function error number is 0.540 and the RMSE is 0.7, as well as the deviation percentage is 28.01, for the Clark method, the Nash function is 533. 0 and RMSE is 0.7 and the deviation percentage is 29.71. This calculation also confirms from the point of view of error measurement that one of the best criteria for observing the difference cannot be RMSE. In the model The detailed analysis of the trending effect, the error of 0.537 in the Nash function is very close to the figure calculated in the similar case (initial aggregated model). However, only this error measurement should not lead to the opinion that the creation of more detailed models cannot improve or destroy the structure of its numerical code. Because although the differences in measurement errors can be ignored in a certain way, the total amount of flow in the aggregated model was equal to 19672395 cubic meters. While the same parameter in the partial model has a difference of 277655 cubic meters. ConclusionIn general, separation of basic discharge with advanced methods such as WHAT cannot necessarily help to increase the correlation between observational data in a continuous model. On the other hand, calculating the discharges that leave the hydrographic network under the heading of deviation from the hydrographic network in the process of flood flows is the basic condition for reducing the model error, regardless of the type of hydrograph selected in the model.
Alireza Shokoohi; Reza Morovati
Abstract
The Lake Urmia is the 20th largest lake and the second hyper saline lake in the world. In recent years, the drying out of the Urmia Lake has attracted attention of many researchers. The main motivation of this study is to evaluate the role of drought in this disaster. For this purpose, Standardized Precipitation ...
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The Lake Urmia is the 20th largest lake and the second hyper saline lake in the world. In recent years, the drying out of the Urmia Lake has attracted attention of many researchers. The main motivation of this study is to evaluate the role of drought in this disaster. For this purpose, Standardized Precipitation Index (SPI) and Reconnaissance Drought Index (RDI) are employed. The data for analysis including precipitation and temperature was provided from two global databases: GPCC for precipitation and NCEP/NCAR for temperature. The study was performed at the time span of 1980-2010 and the results showed that the Lake Urmia basin has experienced a severely drought during 1999-2000. After this period and during eight subsequent years, the negative effects of this drought could not be reduced completely by near normal to wet condition of the basin. Moreover, another severely drought occurred at 2008. RDI value for the 1999 drought was found to be -2.23 which is related to the extremely dry condition. The value of SPI for the same region and same year was obtained as -2.13. This comparison for other severe and extreme cases shows that RDI is more sensitive than SPI at the tails of the phenomenon. It was also observed that after 2000, while the region, in terms of rainfall and drought conditions, is generally close to normal condition, the lake follows a continuous decreasing trend up to the present time. Therefore, one can conclude that in addition to drought, other factors contribute to the drying out of the lake. The results indicated that the anthropogenic effects are responsible to some percent in this disaster. Construction of reservoir dams for agricultural development and other activities for job creation purposes like constructing fish ponds has intensified this crisis. The span of these activities is concurrent to the periods which the drought indices show the fragile condition of the basin in terms of available water resources. This fact emphasizes the importance of drought monitoring as an inseparable part of an IWRM program to prevent a nationwide disaster.
Abdosaleh Rangavar; Gholamali Gezanchian; Hassan Angoshtari; Reza Ghafourian
Volume 1, Issue 4 , February 2010, , Pages 259-265
Abstract
The deposition of transported materials by flood water on soil surfaces in warm and arid region causes some changes in texture, structure, depth and fertility of the soil. According to the study of flood water spreading effect on physical and chemical characteristics of the soil, the study field of flood ...
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The deposition of transported materials by flood water on soil surfaces in warm and arid region causes some changes in texture, structure, depth and fertility of the soil. According to the study of flood water spreading effect on physical and chemical characteristics of the soil, the study field of flood water spreading of Jajarm in North Khorasan province was chosen. This area has located on alluvial fan with 0.75- 1% slop, 146.3 millimeter mean annual rainfall, arid and extra arid climate. For the period of 4 years (1995-1999), the soil samples were collected from recognizable A and C horizons and the depth of 0-30 centimeter (plow layer) from 7 profiles at three primary strips. The quantity of effective parameters on soil characteristics was determined in laboratory. This process was repeated after three times flood water spreading. Obtained data were analyzed: I) by t-student test to compare different properties of soil before and after flood spreading. II) by split plot procedure with three replicates to compare the whole effects at flood water spreading. The samples variance analysis showed that flood water spreading was effective on sand ratio, clay, organic matter, bicarbonate (p<0.05) and was effective too on Ca, Mg, Cl, Na, SAR and EC (p<0.01). There was a significant difference between the samples before and after spreading of flood water. Comparing the average mean of factors including soil salinity, Ca and Mg on A, C and plow layer before and after flood water spreading showed only different between plowing layers, also results showed that the sand to clay ratio and silt in a horizon were decreased. Flood water spreading had no more effect on the other soil characteristics.
Gholamreza Chamanpira; Gholamreza Zehtabian; Hassan Ahmadi; Arash Malekian
Abstract
Utilization of water resources, using a combination of simulation and optimization, are a useful and powerful set for specifying decision-making and management strategies. In this regard, MODFLOW mathematical model, as an efficient and cost-effective tool to evaluate different management options was ...
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Utilization of water resources, using a combination of simulation and optimization, are a useful and powerful set for specifying decision-making and management strategies. In this regard, MODFLOW mathematical model, as an efficient and cost-effective tool to evaluate different management options was used. After providing a conceptual model of the aquifer, requirement data were defined in different versions of the V. MODFLOW (V. 5.33) software. Then, the model was calibrated by the manual method that has higher accuracy than software techniques and validation operations were also carried out. In the simulation process, with the goal of water resource management, the results of modeling and calibration model were used to optimize the groundwater table level. In this study, a linear programming model was used for optimizing the management. Lingo software was used to implement this model and achieve the optimal management. The information needed to solve the problem, was based on the output of a simulation model and optimization options. Due to linearity of objective function, a multi-objective linear programming model was selected to solve the problem. General multi-objective optimization problem with n decision variables, m constraints and p objectives is presented in optimizing relationships. The objectives of the optimization problem were maximizing the profits of agricultural products and minimizing the use of aquifer water. Results indicated that the amount of yield and water use were different before and after optimization. . The amount of annual water consumption before optimization was 92.22 million m3 while after optimization was 75.51 million m3. In other words, the rate of water consumption was reduced by 18 prevent. Results also showed that annual water consumption in agriculture was 31.79 million m3 that shows 65.5 percent reduction compared to the present situation. The amount of benefits before optimization was 47, 798 million Rials, while after optimization it was 63,689 million Rials. In other words, the amount of total profit increased by 33.25 percent. Based on the scenario of a national document (pure water requirement), total profits increased by 15 percent.
Reza Siahmsnsour; Hossein Arzani; Mohammad Jafari; Seyed Akbar Javadi; Ali Tavili
Abstract
The fire is one of the factors that have effect on the natural cycle of ecosystem. This project was established to deal with the effect of the fire on quality features of habitat in the research site of rangelands plants of Zagheh Gorge.It was occur at Khoramabad northeast 35 Km with 33° 29" N, and ...
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The fire is one of the factors that have effect on the natural cycle of ecosystem. This project was established to deal with the effect of the fire on quality features of habitat in the research site of rangelands plants of Zagheh Gorge.It was occur at Khoramabad northeast 35 Km with 33° 29" N, and 48° 42" E, being at 1960 meters above the sea level. This study was formed by travel method, We Used Transects 200 m and plots 1 m that chose vegetation type and plants morphology Both Control area and treatment in Comparison Conclusion show that there are difference significant between canopy cover in the control area, and the fire (p<0.01). Also, after two years, there are not difference significant between organic matter, litter, pebble and rock (p<0.01). But there are significant difference between Soil Conservation level inside and outside of the fire area (p<0.01).This Statistics show that there are difference between the plant production of Class I and III in the control area and the fire with 30.32 and 5.54 in control area and 24.84 and 2.72 gr/m2 in the fire area (p<0.01). The Control area with 69.32 Percent of Canopy Cover is better than the fire area with 51.6(p<0.01) so, high percent of Canopy cover in the Control treatment caused heap of crucibles and numerous branches in this area. Forbs plants, decreased from 46.8 % in the control Canopy Cover area to 35.6 % in the fire area; whereas, grasses increased from 53.2 percent in the control area to 64.4 percent in the fire area. So, the fire is effective on increase of grasses and decrease of forbs.
Abolghasem Dadrasi Sabzevar; Ali Ghazanchian; Mohammad Namaki
Abstract
Social and economical evaluation of watershed management activities, is an important criterion for its validation. The main objective of present study was, identification and analysis of socio-economic impacts of watershed management operations implimented in Gosh village wich is located in 60 km north ...
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Social and economical evaluation of watershed management activities, is an important criterion for its validation. The main objective of present study was, identification and analysis of socio-economic impacts of watershed management operations implimented in Gosh village wich is located in 60 km north of Mashhad. The sample data of this study was consisted of 38 extension workers were randomly selected from the study area based on Cochran’s sampling methodology. The research instrument consisted of three parts in Likert scale. The validity of the questionnaire was analyzed and reliability coefficient was calculated for the questionnaire using Cronbach's alpha ratio of 0.745. These amounts showed that questionnaire has an acceptable ability for data gathering. Factor analysis was the major statistical method. The results offactor analysis indicated that socio-economic effective parameters are increasing garden and farm area, increasing qanats water discharge, increasing rangeland area, and preventing lands flood damages. These four factors, in general, had more than 60 percent of the total variance. Final results indicated that watershed management activities have improved qanats water discharge by flood control and aquifer rechrge and increased the area of Agricultural and garden lands. Also, conseving activities in rangelands caused improving of vegetation cover density and the area of rangelands.
Alireza Majidi; Gholamreza Lashkaripour; Ziaoddin Shoaei
Abstract
The swelling potential of fine-grained soils is one of effective parameters on soil mechanical behavior and erosion and fundamental data required for the design, construction and choosing construction materials. This paper presents a multi-layer perceptron (MLP) artificial neural network (ANN) model ...
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The swelling potential of fine-grained soils is one of effective parameters on soil mechanical behavior and erosion and fundamental data required for the design, construction and choosing construction materials. This paper presents a multi-layer perceptron (MLP) artificial neural network (ANN) model to prediction of the swelling potential of marl soils. Marl soil is a fine-grained soil. The Levenberg-Marquadt learning algorithm was used to train the networks. Existing models prediction of soil swelling potential based on physical and soil index parameters. The present study considers the effects of chemical factors on the behavior and characteristics of fine-grained soils along with the common soil index parameters. The model used physicochemical and mechanical test results from 60 marl soil samples taken from marl formations in the Neogene basin in central Iran (Tehran, Qom and Saveh regions). The models were designed to use different input data sets and structures to determine which soil properties and ANN structures correlate well with the swelling potential parameter. Electrical conductivity (EC) of saturated soil was a new input parameter used in addition to the physical and soil index parameters that include the atterberg limit, activity, content of the clay and silt, initial of porosity ratio and dry density. Values of RMSE, R2 and MCE (evaluation criteria) related to the best model with the physical parameters LL, PI, A, M, C and Yd0 are respectively 0.89, 2.3, 0.84, and for the best model with the physical parameters LL, PI, M, C, Yd0 and EC are respectively 0.92, 1.7, and 0.91.The results of the evaluation criteria models show that inclusion of EC improved the accuracy of the model. It was found that the accuracy of the generalizations and estimations of the ANN models was further increased by clustering data before the data division stage by k-means method to Compared with hierarchical method.
Mohammad Rasoul Rajabi; Ali Nasiri Khiavi; Mahin Kalehhouei; Sonia Mehri; Azam Mumzaei; Khadijeh Haji; Abdulvahed Khaledi Darvishan
Abstract
The present research aimed at presenting a new SWOT strategy for integrated watershed management of Asiabrood in Mazandaran Province. At first, the SWOT matrix and the tables identifying the strategic indicators of internal and external factors were formed and then internal and external evaluation matrices ...
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The present research aimed at presenting a new SWOT strategy for integrated watershed management of Asiabrood in Mazandaran Province. At first, the SWOT matrix and the tables identifying the strategic indicators of internal and external factors were formed and then internal and external evaluation matrices were analyzed. A new strategy used in the discussion of the weighting of SWOT strategies was based on the fact that the final value of each strategy was multiplied by the number of effective strengths and opportunities and the final results were analyzed based on these priorities. Based on analysis of strengths and weaknesses, nine strengths and eight weaknesses were identified. The suitable water quantity and quality with a weight of 0.444, low air temperature with a weight of 0.395, mineral water utilization with a weight of 0.288 and economic poverty with a weight of 0.493, respectively, were the most important strengths, weaknesses, opportunities and threats. According to the internal-external factors evaluation matrix in the SWOT model, the strategy of increasing the sense of satisfaction of residents, based on the conventional method and the new strategy, gave the highest value. With a careful look, it can be concluded that strengthening the sense of satisfaction between residents happens when People problems in different sectors of livelihoods, including economic, social and cultural, have been considered more and, by presenting correct programs, have increased satisfaction and reduced migration to urban areas. In general, it can be concluded that due to the problems and solutions presented in this study, proper and applied planning should be used to compensate for the weaknesses and to strengthen the strengths as much as possible in the development of Asiabrood watershed.
Mohammad NazeriTahrudi; Yousef Ramezani
Abstract
Estimating return period of hydrological processes such as flood flow, maximum discharge, drought and etc, is related directly to selecting a suitable probability distribution function. With selecting a proper distribution function, estimated return period will be more close to actual data and error ...
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Estimating return period of hydrological processes such as flood flow, maximum discharge, drought and etc, is related directly to selecting a suitable probability distribution function. With selecting a proper distribution function, estimated return period will be more close to actual data and error will be reduced. So, it should be tried to select the best probability distribution function. In this study, using daily discharge of western rivers of Urmia Lake, as well as the annual mean method, the data of the drought volume of these rivers were extracted. Several distributions from each of the continuous distributions, such as the continuous distribution of generalized maximums and wakeby, the continuous non-zero Erlang distribution, the continuous Johnson SB distribution, and the continuous boundary of Normal distribution for fitting the data of the dry volume of the western rivers Lake Urmia was used in the 38-year statistical period. Anderson-Darling and Kolmogorov-Smirnov tests used to compare results of each distribution. Also correlations between the data obtained from the sample data and statistical models computed. The results of the frequency distribution of the data of the three rivers showed that among the distributions of the continuous group, the advanced statistical distributions of Wakeby and Johnson SB had the best distribution and also had better performance than the conventional statistical methods.
Ali Talebi; Zahra Eslami; Abdolhossein Abbasi
Abstract
Identification of areas with high potential for flooding in the basin is one of the most important activities in flood control and reducing its damages. In this research, the possibility of prioritizing nine sub-basins from flooding point of view has been studied in Eskandari Watershed, using HEC-HMS. ...
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Identification of areas with high potential for flooding in the basin is one of the most important activities in flood control and reducing its damages. In this research, the possibility of prioritizing nine sub-basins from flooding point of view has been studied in Eskandari Watershed, using HEC-HMS. Also, the priorities of sub-basins were studied using flooding coefficient and peak discharge per unit area experimental methods. In order to run HEC-HMS model, plan rainfall with two, five, 10 and 50 years return periods were used. Flood hydrographs associated with each precipitation were calculated for each sub-basin, using the sequential removal method of sub-basins and removing CN in each sub-basin in each run of the model and their effect were computed in flood generation. Results showed that sub-basin I has the first priority is flooding potential, considering independent and depended sub-basins. Prioritization of sub-basins with two experimental methods had different results that are independent from a particular process. As E sub-basin had sixth priority in flooding coefficient method and third priority in the peak discharge estimating method. By comparing the prioritization of sub-basins in HEC-HMS model in different return periods, results showed that sub-basins prioritization in different return periods has specific process. Therefore, HEC-HMS model is more efficient compared to experimental methods in sub-basins prioritization in flooding.
Mehdi Mahbod; Saeedeh Safari; Mohammaf Rafie Rafiee
Abstract
Determining precipitation spatial pattern in a catchment is necessary for the calculation of hydrologic quantities such as runoff flow and soil moisture content. Sparse meteorological stations as well as spatial variability of precipitation are major obstacles for accurate spatial estimation of precipitation. ...
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Determining precipitation spatial pattern in a catchment is necessary for the calculation of hydrologic quantities such as runoff flow and soil moisture content. Sparse meteorological stations as well as spatial variability of precipitation are major obstacles for accurate spatial estimation of precipitation. The development of remote sensing technology and the possibility of using satellite precipitation products has facilitated attaining spatial precipitation patterns. However, low spatial resolution of satellite precipitation products highlights the need for downscaling methods. Nineteen predictive models were fitted using Regression Learner toolbox in MATLAB software. Annual TRMM precipitation data were downscaled from 2001 to 2017 using Normalized Difference Vegetation Index (NDVI), land surface temperature, land elevation and coordination. Models are divided into five general categories: Linear Regressions, Decision Trees, Support Vector Machines, Ensemble models and Gaussian Process Regression models. Comparing the downscaled TRMM data with gauges data, Boosted Ensemble model had the lowest root mean square error and highest correlation coefficient. On the other hand, two methods of Geographical Distance Adjustment (GDA) and Geographical Ratio Adjustment were compared for calibrating the downscaled precipitation. Smaller errors were obtained using GDA in all models.
Rohallah Taghizadeh Mehrjardi; Fereydoon Sarmadian; Mehdi Tazeh; Mahmood Omid; Norair Toomanian; Mohammad Javad Rousta; Mohammad Hassan Rahimian
Abstract
Recently, researchers are increasingly employed Digital Soil Mapping (DSM) techniques to overcome traditional soil mapping difficulties. Apparently, due to the large heterogeneity of soil environments, sampling may be the most important step in digital soil mapping studies. Therefore, in this research, ...
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Recently, researchers are increasingly employed Digital Soil Mapping (DSM) techniques to overcome traditional soil mapping difficulties. Apparently, due to the large heterogeneity of soil environments, sampling may be the most important step in digital soil mapping studies. Therefore, in this research, we employed three different sampling strategies including Latin hypercube, Fuzzy-K-Means and random sampling to achieve the best spatial distribution of soil samples in an area around 720 km2 located in Ardakan region, Yazd province, Iran. Auxiliary data that used in this study, were including terrain attributes, Landsat 7 ETM+ images and a geomorphologic surfaces map. Based on statistical criteria (i.e. mean and standard deviation), results showed that Latin hypercube is the best sampling method. For instance, in the selected points, the mean of wetness index is 18.19 which is the same as the mean of all area. Similarly, the mean of Multi-resolution Valley Bottom Flatness (MrRVF) in the points selected by Latin hypercube strategy is very similar to all area. Moreover, histogram of auxiliary data in selected points (samples) was more similar to histogram of auxiliary data in all area. Also, the results indicated that a good geographical coverage (Fuzzy-K-Means) does not adequately represent the distribution of the variables. Therefore, Latin hypercube is the best strategy to determine sample locations in our study area and hence, it is recommended that researchers apply Latin hypercube method in future digital soil mapping studies.
