پژوهشی
Ali Ahmadabadi; Amir Karam; Varduhi Sargsyan
Volume 5, Issue 15 , October 2018, Pages 1-16
Abstract
Abstract Introduction Glacial cirques are one of the most important erosional forms in highlands. Landforms are the basis of geomorphology studies. Therefore, depending on the purpose of different researchers, it has been defined differently. It provides an evidence of effective processes and features ...
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Abstract Introduction Glacial cirques are one of the most important erosional forms in highlands. Landforms are the basis of geomorphology studies. Therefore, depending on the purpose of different researchers, it has been defined differently. It provides an evidence of effective processes and features on the earth surface during the past and present era (Etzelmüller, B., Sulebak, J.S., 2000). The basic principle emphasized by the geomorphometry is the existence of a relationship between the shape and its related numerical parameters for describing landforms. Numerical geomorphology studies spatial and statistical features along with the relationships and patterns of the points (Evans, 1972). The automatic classification of geomorphologic units and landforms is mainly based on the morphological parameters (Giles; Franklin, 1998). The morphometrical parameters represent the shape of the earth and the procedures creating them (Jamieson, 2004). On the other hand, the basis for classifying the units in geomorphology is based on the hierarchical theory (Ramesht, 2006). Different methods exist for providing digital elevation model and simulation of surface effects which can be used in different geosciences such as earth hazards, erosion, geomorphology, ecology, hydrology, and other related fields. The efficiency of the geomorphologic indices in dry areas was evaluated by the Wood method (Shayan et al., 2012). Makram et al. (2014) used a topographic index at any point of the digital elevation model to extract landforms. The purpose of this research was to provide a semi-automatic method for the detection and extraction of glacial cirques in Zardkuh Bakhtiari area based on Wood and Evans methods. Methodology In order to achieve the research objectives, a 20m digital elevation model was generated from the 1: 25000 topographic map. Then the first (slope) and the secondary derivatives, a plan and profile curvatures, general curvature, the minimum and maximum curvatures, Longitudinal and Cross-Sectional Curvatures were extracted in ENVI software from the first derivative (slope). The data from the first and secondary derivative layers were standardized as per fuzzy logic, resulting in a single RGB map. By combining the bands of the map, it’s possible to produce significant color outputs. Accordingly, the cirque-like shape holes were identified and extracted manually from the topographic maps. In order to conduct a controlled classification, four cirques were introduced in the RGB map as sample cirques and then the semi-automated model was implemented in the GIS software to find other cirques which were similar to the sample cirques. The Evans and Cox (Evans, 1974) proposed model was used to extract the cirques using the focal point command and the model output was adjusted by supervised classification. Finally, the general accuracy of the classification was evaluated by using a cross-validation method. Result In order to extract the glacier cirques in the Zardkuh area, 26 cirque like holes were manually identified on topographic and slopes maps. Since the purpose of this study was the extraction of the glacial cirques based on the morphometric parameters and characteristics, seven morphometric indices including profile and plan curvatures, minimal and maximal curvatures, longitudinal and cross-sectional curvatures, and general curvature of the region derived from the first derivative or the slope map of the region were used. Then, eight morphometric layers were standardized and combined as per fuzzy. Through layer stack, a RGB map containing all morphometric parameters was created. By changing the bandwidth of this map, significant color outputs, such as the display of aretes, talwegs, slop aspect, height differences, and the like can be obtained. To run the supervised classification model, the morphometric characteristics of four developed cirques were extracted. The values of each of the geomorphometric parameters represent the characteristic features of the landforms. Subsequently, four developed cirques were introduced as a training circus on the RGB map derived from the combination of the morphometric parameters. The results of the supervised classification represents 14 cirque like holes out of 26 holes. Here, due to the complexity of the geology and the high-precipitation region, all holes specified by the MLC model were examined using the cirques classification system introduced by Evans and Cox (1974). From the adjustment of the MLC model and the Evans and Cox definition, by observing the cirques and examining theories of experts, it can be concluded that there are eight developed cirques in the studying area. Discussion and Conclusion The purpose of this research was to provide a semi-automatic method for the detection and classification of glacial cirques landforms in Zardkuh Bakhtiari area. In this study, for each cirque, geomorphometric indices including plan, profile, general, minimum, maximum, cross-section, and longitudinal curvatures were extracted and calculated. The results of this study showed that Zardkuh glacial cirques do not have the most common shape of cirques due to being formed on carbonated formations, but the geomorphologic indices have greatly shown the quantitative and qualitative features of the cirques in the Zardkuh area. By using the MLC model approaches and by conforming its output with the definition of the cirques presented by Evans and Cox (1974), eight fully developed cirques in the studying area were identified. The main reason for this is the carbonate lithology structure of Mount Zardkuh, which has removed the typical shape of the cirques due to the dissolution. Therefore, it can be suggested that the geomorphometric approach in identifying the automation of circuses in these areas cannot be very effective, but it can have a lot efficiency in visual interpretation and identification of landforms.
پژوهشی
Mehdi Dini; Abrahim Mohammadi Aydinlo
Volume 5, Issue 15 , October 2018, Pages 17-35
Abstract
Abstract
Introduction
Due to an intense loss in groundwater level and a high decrease in reservoir capacity, the Marand plain has been banned since 1991. However, since 1994, the groundwater level been dropping year by year. As a result, many wells and qanats have been dried or their discharge capacity ...
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Abstract
Introduction
Due to an intense loss in groundwater level and a high decrease in reservoir capacity, the Marand plain has been banned since 1991. However, since 1994, the groundwater level been dropping year by year. As a result, many wells and qanats have been dried or their discharge capacity has been decreased, which has caused a lot of problems for the operating organizations. In this study, to investigate and manage the groundwater level variation in the Marand plain, three scenarios including supplying all consumption from groundwater resources, supplying drinking and industry consumption from the Aras River, and supplying drinking and industry consumption from the Aras River and applying the optimal management of the consumption for agricultural uses were defined. The water balance equation was used to establish the relationship between input, output, storage in an aquifer, and a variation of groundwater level in the Marand plain was estimated based on the available data (2005-2014). Finally, the zoning of the groundwater level was done for the September 1398 and the results were compared with the September 1393.
Methodology
In this research, the Marand plain with an area of 562.22 km2 in the northwest of East Azerbaijan province was selected as a case study. Investigating the hydrological and meteorological parameters of the Marand plain between the years 1982 and 2013 showed that the average annual precipitation was 283 mm, the average annual temperature was 12.8°C, and the average annual pan evaporation was 104 mm. The aim of this research was to estimate the spatial and temporal variation of the groundwater level of the Marand plain. For this purpose, the water balance estimation was done by using Excel and the zoning of groundwater level variation was done by using ArcGIS. A groundwater level analysis of the Marand plain was carried out based on the 50 observations of wells during 2005 to 2014. In this period, according to the groundwater level data, the aquifer parameters, such as the loss of the groundwater level and the amount of water withdrawal from the aquifer were determined. Then, various scenarios were defined for assessing the status of the aquifer.
Result and Discussion
The analysis of the groundwater level in the Marand Plain in a year statistical period (1982-2013) showed that the groundwater level of the plain had decreased about 16.56 m. Also the average annual groundwater level of the plain decreased about 48 cm between the years 2005 and 2015.
By applying the first scenario, in the next five years, the fall of the groundwater level in the zone 1 will be 2.35 m, in the zone 2 will be 2.25m, in the zone 3 will be 2.6m, and in the zone 4 will be 2.45m.
Also the area of the zone 4 had increased from 246 km2 to 252 km2 which indicated a further fall of the groundwater level in a large area of the plain. By applying the second scenario, in the next five years, the growth of the groundwater level in the zone 1 will be 1.74 m, in the zone 2 will be 1.67 m, in the zone 3 will be 1.93 m, and in the zone 4 will be 1.82 m. Indeed, following this trend, the groundwater level after 14 years will return to the situation of 10 years ago (2005). In addition, after 46 years, it will return to the situation of 32 years ago (1982). By applying the third scenario, in the next five years, the growth of the groundwater level in the zone 1 will be 4.78 m, in the zone 2 will be 4.58 m, in the zone 3 will be 5.29 m, and in the zone 4 will be 4.99 m. Following this trend, the groundwater level after 5 years will return to the situation of 10 years ago (2005). After 17 years, it will return to the situation of 32 years ago (1982).
Conclusion
The aim of this research was to estimate the spatial and temporal variation of the groundwater level in the Marand plain. The results showed that the annual average groundwater level had decreased 48 cm/year between the years 2005 and 2014. Also by applying the first scenario, with an intensified decline in the groundwater level in all zones, the status of the Marand aquifer becomes more critical. For example, in some areas, the groundwater level will decease about 2.6 m. By applying the second scenario, the groundwater level will increase at least 1.67 m and utmost 1.93m and by following this trend, after 14 years, the aquifer will return to the situation of 2005. Also by applying the third scenario, the groundwater level will increase at least 4.78 m and utmost 5.29m and by following this trend, after 5 years, the aquifer will return to the situation of 2005.
پژوهشی
Akbar Hashemi Fard; parviz kardavani; Farideh Asadian
Volume 5, Issue 15 , October 2018, Pages 37-53
Abstract
Abstract
Introduction
Satellite imagery is considered as one of the most important tools of land resource management, due to the wide vision that emerges from one area and its regular repeated coverage. Using remote sensing technology, in particular radar interferometry (InSAR), it is possible to study ...
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Abstract
Introduction
Satellite imagery is considered as one of the most important tools of land resource management, due to the wide vision that emerges from one area and its regular repeated coverage. Using remote sensing technology, in particular radar interferometry (InSAR), it is possible to study the movements and changes caused by phenomena such as earthquakes, volcanoes, glaciers, landslides, salt diopters, and other irregular phenomena. In this research, differential radar interferometry was used to illustrate the displacement of the Earth's surface within the Gotvand Dam area and to investigate the short-term and long-term changes in the incident. There have been several studies conducted to investigate the effects of water reservoirs of lakes and dams, as well as the processing of satellite images of landslides and subsidence. For example, Haghighat-Mehr et al. (2010), using Radar interferometry technique to determine the subsidence rate and Landsat slides of the Hashtgerd plain, used 4 images of the ENVISAT radar during the 4-month period (July 11, 2008 to October 24, 2008), and estimated that the maximum rate of downslope in the plain was 35 mm per month. In addition, Jennat et al. (2009) used the radar interferometry method to determine the surface deformation in the Golpayegan Plain. In the current research, differential radar interferometry was used to illustrate the displacement of the Earth's surface within the Gotvand Dam area and to investigate the short-term and long-term changes in the incident.
Methodology
The term interferometry is derived from the combination of two words including interference and measurement meaning that two waves interact on the surface of the earth. Radar interferometry technique is the combination of two electromagnetic waves on the surface of the earth and the synthetic valve radar technique (Dehghan, 1391). This technique is based on the difference in the ground-back signal phases in two SAR images taken with a time delay or with parallax from an area to extract altitude or information on land surface changes. In order to do this research, 4 images of the SLC Band C, the ASAR satellite ENVISAT for the period of 2007 to 2011, were taken as a research project from the European Space Center with an area of 100 × 100 km2. Through processing of the images with a time interval of one year and more than one year, 4 independent interferograms were obtained. The SRTM DEM region with a resolution of 90 m was used to remove the topographic effects of interferograms. Interfragm processing was performed using Sarscape software. The DOR-VOR file containing the DORIS satellite image capturing information from the European Space Agency was used to correct image distortion caused by the gravitational force of the moon on images. In the first phase of the analysis chain, the data was designed with the aim of constructing the interferometer. Due to the different resolution of this sensor along the radial mile radius (7/80 m) and azimuth (4/5 m), the power dissipation information in line with the range can be converted to the resolution of the earth according to equation (7). A differential interferometer derived from the removal of the topographic effects in the previous stage contains noises that result from the time difference or the time interval received by two radar images. It can also be due to the difference in the basis of the spatial base as well as the resulting spots that have no signal and may result in lower interference imaging; therefore, it is necessary to remove the effects of noise from interference by implementing adaptive filters. Subsequently, the final results of this phase, with the help of Digital Ground Modeling (DTM), were transmitted to Arc GIS for thematic maps. Finally, the results of the landslide detection at the region level, by using field survey and its adaptation to existing information, was controlled and evaluated in the Google Earth environment.
Result, Discussion and Conclusion
The results of this study indicated that the maximum displacement rate in the region reaches about 3.5 cm per year (from 2007 to 2011). To obtain the final landslide map in the area, after processing the pair of radar images, the existing displacements were identified and in the software environment, these changes were derived from each interferometer, combined, and their common areas were deleted. Also, landslides that occur parallel to the flight of the satellite cannot be removed because the landslides in the direction of vision (LOS) of the PALSAR sensor can be picked up. Based on the results of the radar interferometry, the maximum subsidence level in the study area is estimated to be about 3.5 cm per year. In addition, the maximum subsidence rate in Gachsaran and Anabal salt mine is 3.5 cm.
پژوهشی
Reza Ghazavi; Maysam Nadimi; Ebrahim Omidvar; Rasul Imani
Volume 5, Issue 15 , October 2018, Pages 54-79
Abstract
Abstract
Introduction
Information about river flow change and subsequent changes in water quality characteristics can help to manage and plan water resources. The environmental and socio-economic impacts of river flow changes are very important in an environmental water management. Climate change is an ...
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Abstract
Introduction
Information about river flow change and subsequent changes in water quality characteristics can help to manage and plan water resources. The environmental and socio-economic impacts of river flow changes are very important in an environmental water management. Climate change is an important challenge that should influence different parts of human life on earth such as rivers and lakes. The Evaluation of the impact of climate change phenomenon on the hydrological processes of rivers can decrease the challenges of managers and planners of water resources in the next period. The selection of suitable models is important for evaluation and prediction of the effects of climate changes on rivers and watershed discharge. Several hydrological models were used to evaluate the effects of climate change on a hydrological cycle. The Soil and Water Assessment Tool (SWAT) has been extensively used, mainly by hydrologists for watershed hydrology related subjects, since 1993. SWAT model should include both a forecasting model and weather generating model. This means that the generated weather data of the future should be presented to SWAT model for forecasting future rainfall and temperature. This is a new possibility for future river and watershed hydrology studies. The main aim of this study was to evaluate the effect of the future climate change on river discharge of the Heruchay River in Ardebil using SWAT model.
Methodology
In this study SWAT2009 model was used to in investigate and predict the quantitative changes of the discharge of the Heruchay River. For the period of 2014-2041, the daily rainfall and temperature data were predicted under three scenarios of A2, B1, and A1B, using LARS_WG climate model. The simulated data was used as the entered information of SWAT model and the model was implemented for 2014-2041 period.
SWAT is a river basin scale model that should work on a daily time-step. It was developed to predict the effect of the management decisions and climate change on the water cycle. In this study, SWAT model was used for its ability to simulate and forecast stream flow and evaluate the effect of climate change on river discharge.
A topographical map (Digital Elevation Model), climate data (daily rainfall, Maximum and minimum temperature), and soil and land use maps were prepared using GIS and measured data. As the precipitation is an important key input that influences flow and mass transport of the rivers, 5 rainfall gauging stations and 2 weather stations located in the study watershed were used.
Result and Discussion
The results of this study showed that SWAT model had an acceptable performance for discharge simulation during calibration and validation periods with coefficients of variation of 0.81 and 0.8 respectively for calibration and validation. Based on the results of A2 and B1 scenarios, the flow rate of the study river increased, whereas a decrease in the flow rate was predicated based on the results of the A1B scenario. The results of the climatic model indicated that the pattern of the rainfall should change in the prediction periods as the rainfall decreases in the winter and spring, while it increases in the summer.
Conclusion
This study offered a methodology for flow simulation and forecasting of future discharge via SWAT model. The effects of future climate change on flow quantity were examined. In this study, SWAT model was used to predict the impact of the future climate changes on river discharge. Model evaluation was done via Nash and Sutcliffe (NS), coefficients of determination (R2), P-factor, and R-factor. After model calibration, the predicted data under several climatic scenario were presented to the model. The results showed that the average of discharge will increase based on the A2 and B1 scenarios, while it will decrease under the A1B scenario. Therefore, it can be concluded that SWAT is a suitable model for discharge simulation in semi-arid areas. The results of this study also indicated that the combination of the results of LARS-WG and SWAT model should lead to an acceptable prediction of hydrological behavior of the rivers. It is important to notice that in this study only the effects of climate change on river discharge was evaluated. For a sustainable management strategy, other aspects of the watershed such as population pattern changes, land use change, and industrial development should be considered. The impact of the climate and land use change on water quality and soil erosion should also be investigated in the future studies.
پژوهشی
Hamed Jafarian; Abdorreza Vaezihir; Hossein Pirkharrati
Volume 5, Issue 15 , October 2018, Pages 75-94
Abstract
Abstract
Introduction
The investigation into water resources of hard rocks and limestone, is very important because of their quality and role in the supply of the portable water. More than 10 percent of Iran is covered with hard rocks formations which increases up to 25% in the northwest of Iran. Because ...
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Abstract
Introduction
The investigation into water resources of hard rocks and limestone, is very important because of their quality and role in the supply of the portable water. More than 10 percent of Iran is covered with hard rocks formations which increases up to 25% in the northwest of Iran. Because of the high quality of hard rock and karstic aquifers and their suitable location for supplying the drinking water of rural areas, the exploration and exploitation of groundwater from these formations are of interest. In quantitative terms, while the frequency of springs in hard rocks is normally more than that of karstic aquifers, the discharge of karstic springs is normally higher. The hydrochemistry of groundwater in hard rocks and limestone is influenced by aquifer body material, groundwater flow velocity, and residential time of water in aquifer.
Methodology
The study area was located in the west of Urmia City, northwest of Iran as a part of Lake Urmia watershed. The geological units is mainly carbonate rocks (limestone and dolomite).
In order to investigate the quality of groundwater resources, 15 samples of springs were collected and analyzed for the major ions (HCO3, CL, SO4, Mg, Ca, Na, K). Other parameters such as TDS, PH and EC were also measured. Various diagrams and techniques like Durov and Gibbs diagrams, saturation index, and ion ratios were employed to determine the water type and faces and the source of ions. Also some diagrams were used to check water quality for agricultural and drinking usages.
Results and Discussion
Pie diagrams of SO4, Na, and EC showed that the basin area located in young alluviums bearing gypsum caused an increase in SO4 and EC. Marls of Miocene formation in the area also had increased the concentration of Na in some water samples
Based on the samples position in the Piper, Durov, and Gibbs diagrams, most types of groundwater was bicarbonate and calcic types.
The main factors which controled the groundwater chemistry were processes such as ion exchange (due to the presence of clay minerals), weathering, and dissolution of limestone and dolomite formations. It was also found that the watersheds of the large number of springs were located in Permian limestone and detrital Miocene units.
Wilcox diagram showed that most of the samples were in the class C2-S1, which indicated their low salinity and their appropriateness for agriculture. Schoeller diagram also showed that the groundwater region had good and acceptable quality for drinking. Saturation index survey showed a highest value of unsaturity related to dolomites for the samples which is influenced by Silvana dolomitic formation. Under saturity of samples related to gypsum, halite, and anhydrate was expected because of the absence of saline gypsiferous formations in the area.
Conclusion
The results of this research showed that the groundwater of the study area has a water with calcic and bicarbonate types with a high hydrochemical quality, which is appropriate for agriculture and drinking uses. It was also found that lithology has a major role in the hydrochemistry and quality of the groundwater. Weathering and solution of Routeh and Tertiary limestone karstic formations, and Silvana dolomitic formation have more impact on the groundwater quality of the study area. However, alluvial gypsiferous and Miocene formations with marl beds have a little impact on the quality of groundwater in the north, center and east of the area.
پژوهشی
Amir Sasfari; Hamid Ganjaeian; Zahra Heidary; Mojdeh Fraidoni Kordestani
Volume 5, Issue 15 , October 2018, Pages 95-114
Abstract
Wide areas of dry and non-glacier lands of the earth are covered with carbonate formations prone to karstic. Indeed, about 20 to 25% of the world's population live in karstic areas or get their water requirement from karstic water resources. Karstic areas are important because of the following reasons. ...
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Wide areas of dry and non-glacier lands of the earth are covered with carbonate formations prone to karstic. Indeed, about 20 to 25% of the world's population live in karstic areas or get their water requirement from karstic water resources. Karstic areas are important because of the following reasons. Firstly, they have an important role in providing and feeding aquifers. The karstic aquifers have also high heterogeneity and spatial diversity in terms of the development of karstic. In addition, they are formed in various forms and developed in karstic regions. For regions such as Iran which does not have enough water resources and 11% of its area covered with karstic, the issue is important. Due to the complex nature of karstic system, especially from the perspective of geomorphology, no models have been offered upon which all aspects of the system can be investigated. Due to the sensitive nature of a karstic system, in the planning of karstic areas, efforts have been made to develop the rate of change and sensitivity of karstic within the framework of the appropriate model or models. Accordingly, in this study using the OWA, fuzzy logic, and network analysis (ANP), the development of the processes and karstic aquifers are discussed in the Qaresou basin.
Methodology
This research was based on field, instrumental, and library techniques. Firstly, using the topographic maps, the basin area of the study was determined. The main data of the research were topographic maps of 1: 50000, geological maps of 1:100,000 and satellite imagery. In this research, 8 factors including lithology, fault, slope, aspect, elevation, river, rainfall, and climate have been used to determine the areas susceptible to Karstic development in the Qaresou Basin. For this purpose, the first step was to prepare information layers using some software. In the last step, considering the parameters, the potential of the region for the development of the processes and the development of karstic aquifers was evaluated. For this purpose, two models of fuzzy logic and sequential weighted averaging (OWA), as well as an analysis network (ANP) model, were used for the zoning and weighting the information layers.
Results and discussion
The 8 parameters of elevation, slope, aspect, lithology, fault, climate, rainfall, and rivers were used in order to evaluate the development of karstic in the study area. In the lithology and climatic condition layers, the first class had the lowest value in the development of karstic regions and the upper classes had the highest value. In the lithology layer, the first class had formations which had less potential for permeability and the sixth class was calcareous layer with a great potential in this regard. In the climate classes, the first class had a semi-arid climate and had a low score, but the fifth class had a wet climate with a high score. The distance from faults and rivers showed that the areas near faults had a high potential to develop the karstic processes. The pattern of the slope and aspect indicated that the regions with the lowest slope as well as aspects to the north had the highest score. The pattern of the height and precipitation also suggested that areas with significant elevation and more precipitation had great potential in the development of the karstic processes. The pattern of distance from the river showed that the areas away from the river had higher potential and score.
Conclusion
Considering the parameters that were considered in order to evaluate the development of the processes and the karstic aquifers, as well as considering the criteria and sub-criteria, the final maps were obtained. Based on the results of the effective factors in the development of the Karstic, the studied basin is divided into five levels of high, relatively high, moderate, low, and very low development.
The evaluation of the final maps indicated that in both maps of the north and northeast regions of the basin there is more development. In addition, due to the favorable climatic, geomorphological, and geological conditions, a large part of the region has a high development that is why the studied basin has a high potential for karstic water resources. Considering that there are differences in fuzzy logic and sequential weighted average (OWA) methods in integrating and combining information layers, the final results have differences in terms of class size. Indeed, in the OWA method because there is more moderation, the difference between the classes is less than the fuzzy logic method, but the general trend of the development in both methods is almost consistent and the extent of development reduces from the north and northeast to the south and southwest.
پژوهشی
Zeynab Alimirzaei; Rafat Zare Bidaki; Rasool Zamani-Ahmadmahmoodi
Volume 5, Issue 15 , October 2018, Pages 115-133
Abstract
Abstract
Introduction
Drought is a natural phenomenon that may occur in all areas of land under any climate conditions. Scientific study of drought is essential for water resource planning and management and for mitigating water shortages. Low rainfall is the main cause of the occurrence of drought. ...
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Abstract
Introduction
Drought is a natural phenomenon that may occur in all areas of land under any climate conditions. Scientific study of drought is essential for water resource planning and management and for mitigating water shortages. Low rainfall is the main cause of the occurrence of drought. Precipitation reduction in a period of time than long term average of an area is defined as meteorological drought. Hydrological drought is defined as a significant reduction in available water of all forms in a landscape. Meteorological droughts lead to hydrological droughts with decreasing flow rates and aquifer discharge.
Methodology
In order to quantify drought phenomenon, some indicators on the basis of drought definitions or computational methods were provided. These indicators are calculated for a single point, but the extent of the drought and its severity vary in different parts of the basin and it is the key point of water resource management and planning for mitigation of drought crisis. The purpose of this study was to investigate the spatial and temporal variations of climatic and hydrologic drought in the North Karun Basin. In this study, some of the meteorological and hydrological indicators such as Deciles (DI), Z score, Standardized Runoff Index(SRI), Stream flow Drought (SDI), Standardized Water Index (SWI) and Groundwater Resource Index (GRI) were calculated to assess the status of the study area. In order to expand point information and convert it to spatial information, after calculating different indices, the meteorological and hydrological drought severity mapping was done using Kriging and IDW(with power 1, 2, 3 and 4) methods.
Result and Discussion
The results of the meteorological drought indices showed that during the 30-year period (1974-2014), the studied area had experienced a severe drought only once between the years 2007 and 2008. The SDI index showed that the river flows had declined at the same time as the meteorological drought between the years 2007 and 2008. In addition, the river flow drought (2007-2008) is clearly obvious in the next water year. In recent years, the SDI has fluctuated from moderate to severe drought, and in general, all stations experienced a moderate drought. SWI indicator analysis showed that groundwater level drop in the North Karun Basin occurred in 2007 and 2008, that has been delayed by one year to the meteorological drought. The results of the GRI in the North Karun Basin showed that the hydrological drought began between 2007 and 2008. Due to the sharp drop in groundwater level, the severity of the groundwater drought in recent years has been dramatically increased in the plains of the study area. The analysis of the Z index map indicated that while the drought is more intense in the eastern parts of the basin, it is less severe and intense in its northern and southern parts. Groundwater drought zoning showed that the severity of groundwater drought in the northeast and southeast of the plains is high. The Shahrekord plain is one of the most important plains in the North Karun Basin, because it has the main concentration of agricultural and animal husbandry activities and has undergone a sharp decline in groundwater over recent years. The groundwater level of this plain reached its lowest level between the years 2013 and 2014.
Conclusion
In general, the findings indicated that sever meteorological droughts in the time period of thirty years (1986-2015) occurred in two years (2000-2001 and 2007-2008). But its impact on surface flow and groundwater recharge is significant due to anomalies in the rainfall – runoff process and excessive withdrawals from the groundwater resources. The meteorological and surface water droughts periods in this basin often take one to two years. The duration and severity of droughts, especially in groundwater resources, have been significant in recent years. The results also showed that geostatistical method of kriging with exponential and gaussian model has a high ability for drought zoning. Also, it can be understood that the eastern part of the area has received fewer precipitation than the other parts. This result is also derived from the zoning of groundwater droughts that the eastern parts of the plains are more severely affected by drought. In general, hydrological droughts in the north Karun Basin are more intensive in the southern and southeastern regions. Simultaneous use of the meteorological and hydrological indicators can be a useful tool for the separation of the meteorological and hydrological droughts as well as the assessment of drought in the region.
پژوهشی
Mohammad Omidfar; Hashem Rostamzadeh; Behroz Sari Sarraf
Volume 5, Issue 15 , October 2018, Pages 135-152
Abstract
Abstract
Introduction
Flood phenomenon is one of the atmospheric hazards whose frecuncy is remarkable in the northwest of Iran and every year, there are a lot of Casualties and financial losses on different parts of the study area. The aim of this study was the feasibility of using the new Doppler ...
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Abstract
Introduction
Flood phenomenon is one of the atmospheric hazards whose frecuncy is remarkable in the northwest of Iran and every year, there are a lot of Casualties and financial losses on different parts of the study area. The aim of this study was the feasibility of using the new Doppler radar technology to predict the short term flood phenomenon and send timely warning to the relevant organizations and residents of the flood prone areas. To this end, Tabriz Radar products, which can be expanded in a three dimentional structure based on the direction and speed of movement and water content of cloudes in the event of flood of the gallezar village, were selected and carefully monitored. The resuls showed that due to the ability of the radar to penetrate into the clouds and its appropriate spatial and temporal resolution, depending on the formation location and the speed of development of super cells, flood phenomena can be detected several hours before the occurrence. In case of coordination with the crisis organization and prompt warning, it can decrease its damages.
In recent years, Doppler weather radar is one of the new remote sensing technologies that can give valuable information about cloud and type of precipitation. The new technology of meteorology radar can be fruitful in the identification, monitoring, and early warning, and, eventually, reducing damage inflicted to the environment. Therefore, this study aimed to evaluate the efficiency of the products of Doppler radar in monitoring the cells of showery severe rain-producing clouds. The aim of this study was also to evaluate the performance and functional advantages of radars in monitoring and analyzing the characteristics of flash flooding covective cells in the northwest of Iran. For this aim, the production or incoming , direction of motion, and attenuation of floodable convective cells in the study area were monitored by 15-minute time steps by three main radar products including maximum display (MAX), surface rainfall intensity (SRI), and precitipation accumulation. The obtained results can be applied in establishing scientific information and missions in establishing rapid meteorological warning system and, hence, making required decisions in reducing casualties brought about by flood.
Methodology
The area under study is part of the northwest of Iran that is located in the effective range of Tabriz radar. According to the power of the radar waves, its effective range can be used up to 250 km radius. For analytical studies, like this study, it is applicable to the whole range of the northwest of the country. A variety of radar products produced by the radar reaches to more than fifty products. Each product has different output specifications and performance with graphics, charts, and meteorological signs. Of these products, about 20 products are generated and stored by Tabriz radar. Some of the applied products in this study will be briefly discussed. The maximum product of the exhibition is displayed on a graphical screen after processing. It contains information which displays the maximum height and interior density of the cloud. Surface rainfall intensity product showed the intensity of precipitation at a specific level. For this purpose, a surface close to the ground was determined and by the equation between Z-R, the value of z reflection was transformed to the intensity of the rainfall. To achieve the objectives of the study, Azarshahr flood event, which occurred in 2017, was selected using the currently reported weather codes in synoptic stations in the studied area. In sampling, there was an atempt to place cases in different geographical distances and directions with respect to the radar. For the close monitoring of the showers, from the early days of the reported barrage above, the radar products were examined with 15-minute intervals. On the basis of these images, time and place, route, time and peak locations of the activities, and the death of rainfall cell were monitored.
Result and Discussion
In this study, floodable convective cloud cells producing heavy rain showers grew within a few hours from small cumulus clouds (type one without rainfall), into cumulonimbus flood-causing clouds, along with heavy rainfall and hail. The 4 April 2017 flood event convective rainfalls, which created heavy rains in small area was selected. Naturally, in the selected case, the rest of the stations had meager amount of rainfall that was not possible to recognize these convective cells with satellite images or by synoptic maps. Doppler radars had tremendous role in detecting, routing, and monitoring of the maps. Indeeed, with proper management and timely warning, a significant amount of the casualties caused by the phenomenon can be decreased. Cooperation with the crisis organization and prompt warning can also decrease its damages.
Conclusion
Doppler radars have great potential to improve the quality of the rainfall data because of the ability of producing data with a spatial resolution of less than 500 m and 15-minute temporal resolution and its wide coverage. The results showed that the flood event which occurred on April 4th, 2017 was a local rainfall. It was formed in a short time and at a relatively small scale and was invisible by meteorological observations and satellite images. Primary cloud cell (cumulonimbus) of an intense shower rain was formed in the early hours of the morning and gradually was grown and reached the strongest form in the afternoon and early evening and created an intense flood in the form of a shower rain. After intense rainfall event, the cloud cells became weak and collapsed. In some cases, the peak of its convective clouds got to 10 km.
پژوهشی
Hafez Mirzapour; Ali Haghizadeh; Rezvan Alijani; Zahedeh Heydarizadi
Volume 5, Issue 15 , October 2018, Pages 153-169
Abstract
Abstract
Introduction
The importance of planning and managing water resources, as well as an increasing population growth and the limitation of surface water resources in the country, has made the accurate prediction of rivers' flow by using modern tools and methods of modeling, as an inevitable necessity. ...
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Abstract
Introduction
The importance of planning and managing water resources, as well as an increasing population growth and the limitation of surface water resources in the country, has made the accurate prediction of rivers' flow by using modern tools and methods of modeling, as an inevitable necessity. In addition, proper river flow prediction in river management, flood warning systems, and especially planning for optimal operation is required. In order to predict the flow of a river, several methods have been developed over the past years. In general, these methods can be classified into two categories of conceptual models and models based on statistics or data. The basis of the most of the predictive methods is the simulation type of the current status of the system which is called "modeling". Considering that in most cases the conceptual models require accurate data and knowledge of processes affecting the phenomenon, and this has so far been accompanied by many problems, researchers have turned to the statistical models. Over the past four decades, time-series models have been widely used in predictive river flow as a statistical model. In each science, the collected statistics corresponding to the variable which is going to be predicted and which is available in the past periods are called time series. Indeed, a time series is a set of statistical data collected at equal and regular intervals. Statistical methods that use such statistical data are called analytical methods of time series. The basis of many decisions in hydrological processes and decisions on exploitation of water resources is according to the prediction and analysis of time series. Assessment of the temporal changes of base flow in watersheds, particularly in low flow seasons is very important.
Methodology
Time series models are represented in three main forms: self-correlated models (AR), moving average (MA) models, and self-correlated and moving average (ARMA) models. The condition of using these models is the static nature of the used data. If the data is not static, the data series must be static with the existing methods. The existence of "I" in ARIMA indicates the non-static nature of the original data and the change in the data for modeling. If the data series has a cyclic and rotational state, the type of model is seasonal or SARIMA. Time series models have two components of (p, d, q) and s (P, D, Q). S (P, D, Q) is a seasonal component. P and q are respectively autoregressive parameters and non-seasonal moving average. P and Q are autoregressive parameters and seasonal moving average. The other parameters, D and d, are differential parameters for making the time series static.
Result
The statistical and probabilistic models have been presented and developed. This study aimed to analyze and compare the performance of series 30 and 56 years and monthly average discharge related to the Kakareza River in the Selsele city and the Kashkan Afrineh River in the Poldokhtar city in Lorestan province. To this end, the first climate in this region was determined. Next, the autocorrelation function and partial autocorrelation real data draws in XLSTAT software was done. Subsequently, the data was normalized using the Box-Cox and logarithmic. Then, the data trend that indicated non-stationary was determined. After that by using the different operator in MINITAB software, the data trend was removed and the suitable model with the lowest Akaike was selected. Then both periods 12 and 24 months for the two regions were simulated. Results showed that the selected models in 12 and 24 months periods had respectively a correlation coefficient of .92 and .86 for the kakareza river and .94, .88 for the Kashkan Afrineh river.
Discussion and conclusion
The most significant difference between the observed and the simulated values is in two months of Esfand and Farvardin. In addition, due to high precipitation, there was a significant increase in the amount of discharge in Farvardin. According to the climatic conditions in the study areas, the model showed a better performance in semi-arid areas.
پژوهشی
Kazem Nosrati; Ali Rajabi Eslami; Mojtaba Sayadi
Volume 5, Issue 15 , October 2018, Pages 171-190
Abstract
Abstract
Introduction
Groundwater is the most important source of drinking water in most communities. Water quality assessment and hydrogeochemical agents that effect water quality due to its direct impact on consumers' health is essential. Before 1970s, the focus of most studies was on physical properties ...
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Abstract
Introduction
Groundwater is the most important source of drinking water in most communities. Water quality assessment and hydrogeochemical agents that effect water quality due to its direct impact on consumers' health is essential. Before 1970s, the focus of most studies was on physical properties of water, but in the recent century developments in sciences (i.e., chemistry and geology) researches on groundwater quality has improved. Approaches to estimate the effects of time and place on the quality and quantity of groundwater are univariate and multivariate statistical techniques. Water resource is getting more and more important in drought and interior regions such as Iran which is located in a desert belt. Therefore, the classification and analysis of groundwater quality in Mallard city in the margin of an interior basin by using multivariate statistical analysis were the aims of this study.
Methodology
The City of Mallard is located in the border of three provinces consisting of Markazi, Tehran, and Alborz. The study area has geographical coordinate with 50° 20´ to 51° eastern longitude and 35° 28´ to 35° 43´ northern latitude. The data used in this study was prepared by rural water and wastewater of Mallard. Thirteen quantitative parameters in thirty-one water wells during 2010-2015 were selected. The data was divided into three qualitative classes on the basis of a hierarchical cluster analysis. Furthermore, to identify the most important water quality parameters in each homogeneous region, a factor analysis on the basis of main component analysis method was used. In order to recognize the suitability or merit of the data, before performing factor analysis, KMO and Bartlett's spit test were done. Hence, the number of factors and main components of groundwater quality were determined. Furthermore, to a better recognition of sample's number on the basis of connection between the factors and their values a graph was depicted that breaks in the axis of the graph defined the number of the main components. In this study, to show the results of the cluster analysis, factor analysis, and one-way variance analysis, SPSS software was applied. After performing a statistical analysis on the basis of the interpolation method and by applying Arc GIS software, the study area was mapped. After registration of the location of any well by GPS, the estimation of use land and geological states was done.
Results and discussion
Based on the quality of water wells in Mallard city, all wells were divided into three qualitative clusters. Accordingly, ten wells were settled in the first cluster, twelve wells in the second cluster, and nine wells in the third cluster. The qualitative zoning showed Mallard's wells in terms of the cluster analysis. The distance between the wells is due to solidarity and self- solidarity between qualitative characteristics of the water wells. The cluster analysis on Mallard groundwater quantitative data resulted in three quantitative classes for water wells in this city. Therefore, each cluster was analyzed by the measurement of a meaningful data and accordingly quantitative status of the clusters were determined. From first toward third clusters, the concentration of all quantitative parameters except PH increased in a meaningful way.
Conclusion
The results revealed that the water quality in the third cluster was low. In each cluster, three factors, as the main parameters that effect and change the water quality, had respectively total variance of 92.85, 83.58, and 88.93. In addition, evaporate formations, using chemical fertilize, household wastewaters, and non-principle repulsed of poultry farm garbage were the effective parameters on water quality changes in the study area.
