Geomorphology
Naimeh Rahimi; Somaiyeh Khaleghi; Alireza Salehipour Milani
Abstract
In the east of Jask City, four severe floods with high discharge occurred in the Sadij River between 2009 and 2019. This research aims to evaluate the morphological changes of the Sadij River due to the occurrence of floods over a period of 11 years and in the four significant floods during 2009, 2014, ...
Read More
In the east of Jask City, four severe floods with high discharge occurred in the Sadij River between 2009 and 2019. This research aims to evaluate the morphological changes of the Sadij River due to the occurrence of floods over a period of 11 years and in the four significant floods during 2009, 2014, 2017, and 2019. Geomorphic effects on the river were extracted using Landsat and Google Earth satellite images. GIS10.5 software and the Fluvial Corridor were used to investigate the morphological changes caused by floods in the river. The erosion and sedimentation levels were evaluated with the RNCI model. The results showed that the average width of the channel decreased by about 38 m, and the length of the river increased by about 3510 m in the floods between 2009 and 2019, corresponding to the increase in the curvature coefficient of the river from 1.40 to 1.56. According to the results of RNCI, the flood of 2019 with a discharge of 1167.73 m³ caused the highest amount of erosion compared to the other floods. Among the studied reaches, the most changes in geometrical parameters belonged to reach B
Hydrogeomorphology
Mohammad Mehdi Hosseinzadeh; Ali Reza Salehi Milani; Fateme Rezaian Zarandini
Abstract
Floods, as natural and unexpected events, have occurred frequently in recent decades. To reduce the damages caused by floods and flood management, it is mandatory to assess the possibility of danger and prepare maps of possible danger zones. In recent decades, many destructive floods have occurred in ...
Read More
Floods, as natural and unexpected events, have occurred frequently in recent decades. To reduce the damages caused by floods and flood management, it is mandatory to assess the possibility of danger and prepare maps of possible danger zones. In recent decades, many destructive floods have occurred in the Nakarod catchment. Because of this, to manage floods, reduce damages, and properly use water resources, the flood potential of the sub-basins of the Nakarod catchment has been studied. Neka River is 176 km long, and it is one of the important rivers of Mazandaran province and one of the catchments of the Caspian Sea. In this research, to prepare a map of the sensitivity of the sub-basins to the flood risk of the basin, 11 influencing parameters have been used, which includes elevation, slope, distance from drainage network, drainage density, flow accumulation, rainfall, land-use, geology, stream power index, topographic wetness index and curvature of the topography. The layers were weighted using the Analytical Hierarchy Process (AHP); and eventually, by using the weighted linear combination method in ArcGIS software, the standardized layers were multiplied by the corresponding weight, and then the results of all the variables were added and accumulated together, and the final sensitivity map was divided into five classes. The results of the research indicate that flood sensitivity is different in the sub-basins of the Neka RiverAmong the effective environmental factors in flooding, the elevation and stream density were the most influential factors in the flood risk of the Neka catchment.
Hydrogeomorphology
Abolfazl Faraji mondared; shahram roostaei; Davoud Mokhtari
Abstract
Due to their geomorphological characteristics, alluvial fans are part of the high flood risk area. Placement of human phenomena in flood zones is a factor that intensifies the instability of currents. For this purpose, in this research, we applied the location of human phenomena in the geographical space ...
Read More
Due to their geomorphological characteristics, alluvial fans are part of the high flood risk area. Placement of human phenomena in flood zones is a factor that intensifies the instability of currents. For this purpose, in this research, we applied the location of human phenomena in the geographical space of Pardisan in the flood zone with an applied-experimental method. To achieve this goal, the HEC-RAS-6 hydraulic model has been used as a working tool. Due to the size of the area, the area was divided into 15 sub-basins. First, the sub-layers of rivers and floodplain network were extracted, then human phenomena in the studied space were extracted and located on the RAS background map. Then the measured data and values were considered and implemented in the model. By locating the phenomena and considering the conditions of the alluvial fan flood, it was determined that the 100-year-old flood in the area of railway and communication lines, stairs in the west of Pardisan, west side of Payamnoor University, upstream of Pardisan town and also agricultural lands, has a high vulnerability rate. In general, despite the newly established Pardisan town, urban design and subsequent study and modification of the route did not match the geographical features of the region and the prospect of instability has prevailed in the geographical space of the area. It is suggested that for the future development of the city, the flood route be improved and monitored upstream to maintain environmental sustainability.
Hydrogeomorphology
Amir Saffari; Sara Mohammadi; Ali Ahmadabadi; Sahar Darabi
Abstract
Floods are one of the most important natural hazards that often affect millions of people around the world annually with huge impacts. In recent years, due to the occurrence of frequent floods in the watershed of Cheshmekile River and the subsequent damage caused by floods, the need to pay attention ...
Read More
Floods are one of the most important natural hazards that often affect millions of people around the world annually with huge impacts. In recent years, due to the occurrence of frequent floods in the watershed of Cheshmekile River and the subsequent damage caused by floods, the need to pay attention to the zoning of the flood risk in the investigated basin is becoming more apparent. Among the different methods for preparing flood zoning maps, statistical methods are more important due to their simplicity and acceptable accuracy. The aim of this research is to compare the reliability of Shannon entropy models, frequency ratio and witness weight in the context of flood zoning in Cheshmekile watershed. In this research, the criteria of slope, elevation classes, soil type, topographic humidity index, distance from the river, geology, land use, watercourse density, NDVI and rainfall have been used. The probability of flood occurrence has been calculated for each class of each parameter. The calculated weights for each class were applied in the ARC GIS software in the relevant layers and flood zoning maps of the area were obtained. The final maps resulting from the implementation of these three models in the region were divided into 3 low risks, medium and high-risk classes. And finally, the reliability of each model was evaluated using the system performance characteristic curve (ROC). The results have shown that frequency ratio (FR), weight of evidence (WOE) and Shannon entropy (SE) techniques have the highest accuracy in predicting the occurrence of floods.
hydrogeology
Fariba Esfandyari Darabad; Zeinab Pourganji; Raoof Mostafazadeh; Maryam Aghaie
Abstract
Floods as destructive natural hazards need to be predicted in accurate way through evaluation of the hydrological response of watersheds to the effective input rainfall. Due to the variety of rainfall-runoff models, it is very important to choose a suitable model that can simulate the hydrological behavior ...
Read More
Floods as destructive natural hazards need to be predicted in accurate way through evaluation of the hydrological response of watersheds to the effective input rainfall. Due to the variety of rainfall-runoff models, it is very important to choose a suitable model that can simulate the hydrological behavior of the watershed. In this study, various rainfall-runoff transformation methods have been evaluated, including triangular, broken triangular, variable triangular and SCS-curvilinear unit hydrograph methods in Nenekaran watershed, Ardabil province. In this regard, the Wildcat5 hydrological model have been used to this purpose. The precipitation amount at the 25-year return period was calculated using Cumfreq software. After preparing the land use map of the study area using satellite images, the area of each land use in the area has been calculated using ArcGIS software. The precipitation value and the time of concentration were considered constant during the simulation procedure. The results showed that the SCS method had the highest runoff of 44.50 cubic meters per second. The minimum time to the peak was 2.19 hours and the variable triangular method had the lowest peak flow rate. The simple triangular method has a maximum time to peak of 4.51 hours, which shows the great difference between the hydrograph of the SCS method and the other three methods. The difference in the nature of the methods, the watershed condition, and the suitability of estimating tc and CN parameters should be considered in rainfall-runoff transformation methods.
Hydrogeomorphology
ahad habibzadeh; Massoud Goodarzi; Malek Rafiei
Abstract
1-IntroductionThe common method of supplying water for agricultural purposes is flood irrigation used in semi-dry areas from past times. Flood utilization has long been one of the common water supply methods among farmers in dry areas of the world due to inaccessibility to sustainable surface or underground ...
Read More
1-IntroductionThe common method of supplying water for agricultural purposes is flood irrigation used in semi-dry areas from past times. Flood utilization has long been one of the common water supply methods among farmers in dry areas of the world due to inaccessibility to sustainable surface or underground water resources. In North America, Indians have used simple flood irrigation methods for centuries (Hudson, 1975). The studied area is located at 110km from the center of the province, north of Uremia Lake and the drainage basin surrounding Tasoj city at 45°18' to 45°33' eastern longitude 38°20' to 38°24' northern latitude. The area includes ten sub-basins overlooking the city of Tasuj and the villages of Angashtjan and Amstajan, and its area is 9616.79 ha. The average height of the area is 1700m with an average rain of 271mm in 20 years and an average annual temperature of 13.4°C. The region is climatically affected by polar air from the north, polar sea from the northwest, tropical climate from the south. The region's climate is cold semi-arid, and the rainfall regime is in the Mediterranean. The main feature of this regime is intense rainfall, spring rainfalls, and intense snowing in winters, along with several months of drought in summer and late spring. The land use of this region includes farming gardens 938ha, irrigated aquaculture 2050ha, and dry farming 420ha. The cultivation pattern of farms and gardens mostly includes apple, walnut, Elaeagnus Angustifolia, almond, cherries and alfalfa, wheat, barley, and chickpeas that are the farming lands with aridity problems. Angoshtjan and Amstejan ponds and watersheds have two U.R.F upper Miocene geologic formations and the equivalent formations of Qom with marl, limestone, and sandstone deposits that produce high sedimentary floods (Habibzadeh, 2018). One of the main objectives of flood distribution projects is the improvement of the status of natural resources in flooding plains on the alluvial fans of the outflow of the problematic watershed, the storage of precipitation, supply of underground sources, supply of required water for crop and farming, quantitative and qualitative changes of vegetation, changes in plant composition and increase of plants for feeding and increase of soil fertility. Lashanizand et al. (2010) studied the changes in surface water quality of Kashkan basin due to periods of water scarcity and watery and for this purpose, 12 parameters of water quality and discharge statistics of eight hydrometric stations in 30 years and concluded qualitative changes from The ascending and descending trends follow the periods of watery and aridity. The purpose of this study, while presenting a qualitative analytical method of floods, is to use floods in agricultural water supply in the agricultural plains north of Lake Urmia.2-MethodologyThe research project investigating the effects of incoming flood quality on flood spreading performance was carried out by the author to create model areas for flood exploitation for agriculture, promotion, and development of flood distribution systems in arid and semi-arid regions. Samplers were installed along the flood paths of the Angoshtjan and Amstejan sub-basins at the entrance of the plain and in three locations of impoundment system, above and below these systems with gages. After the installation of samplers, the flood sampling was done to this end, sampling was performed three times in 2011, two times in 2012 and one time in 2014; the number of samples to be taken was determined based on the flood discharge and the height of samplers and sent to the laboratory for analysis. The results related to the differentiation of the sampling location have been classified using Model and Wilcox diagram (Habibzadeh, 2017).3-Results and DiscussionThe main limitation in agriculture, especially in arid and semi-arid regions, is the supply of water needs. In such areas, water is the basis for planning for agricultural development. Every year, much water flows out of reach in the form of runoff or floods and causes much damage to agricultural lands, residential lands, and roads (Mesbah and Negahdar, 2015). According to the purpose of the research, it was necessary to prepare information about the amount of rainfall and floods in the region. For this purpose, the amount of flood extraction was calculated and collected based on 20-year statistics of rainfall and floods in the region. The average monthly rainfall and flood storage are shown in Table 1. Flood samples were sent to the laboratory for qualitative analysis during six floods over three years. Laboratory analyzes including salinity, acidity, anions, and flood cations were performed. The lowest salinity, or EC, is related to the flood of the Amstajan river with 345 μm /cm, and the highest is related to the flood of the Angoshtjan river with 799μm / cm. Table (1): Average monthly flood rate in Tasuj study catchments (2000-2020)MonthPrecipitationmmFlood storagem3Flood%April39.653054.039.1May51.751005.237.6June13.82875.02.1July6.4865.70.6August4.11432.71.1September9.328.60.0October11.72134.21.6November35.55432.14.0December25.40.00.0January14.20.00.0February28.20.00.0March29.618698.713.8 269.5135526.2100.04-Conclusions In this project, to access the 2.5 million m3 outflow flood of Amstejan and Angoshtjan villages, the qualitative analyses of flood samples have been done based on Wilcox, Piper, and Stiff hydro-chemical diagrams. The mean electric conductivity in Amstejan sub-basin floods is 350mho/cm, and for Angoshtjan, the sub-basin is 600 mho/cm. The floods have relatively alkali acidity or neutral. The highest values, 8.06 and 8.04, are related to the inflow flood of the reservoir of flood collection. The quality of floods in terms of irrigation water classification of Wilcox method, where salinity and sodium rate are the most important criteria, is mostly in the C2S1 area. In terms of classification of irrigation water, C2, water with medium salinity that can be used for plants with medium tolerance to salinity, S1 is low sodium water which is good for irrigation of all types of soils and is not risky; therefore, they are good waters for agricultural purposes.
Mohammad Hossein Rezaei Moghaddam; Davoud Mokhtari; Majid Shafieimehr
Abstract
Floods are one of the most common natural hazards, causing significant loss of life and property each year. The purpose of this study is to determine the risk areas of floods in Shahr Chai Miyaneh watershed. To implement this model, different layers such as slope, aspect, elevation, distance from river, ...
Read More
Floods are one of the most common natural hazards, causing significant loss of life and property each year. The purpose of this study is to determine the risk areas of floods in Shahr Chai Miyaneh watershed. To implement this model, different layers such as slope, aspect, elevation, distance from river, river density, land use, vegetation, lithology, rainfall and soil were used. The final analysis and modeling was performed using the Vikor model. The results showed that rainfall, slope and distance from the river have the greatest impact on the occurrence of floods in this watershed. Also, according to the obtained results, 5.2 and 1021.7 square kilometers, respectively, are located in a very high-risk and high-risk area. Dangerous and very dangerous areas are mainly located along the main river and mountainous in the steep logic. Due to the high slope and height of the region, it plays an effective role in the amount of runoff and flow peak floods. Also, in the catchment area of Miyaneh Chai city, 2.2, 27.2, 1099.6, 1021.7 and 10.2 square kilometers, respectively, are in a very low risk, low risk, medium, high risk and very high risk area.
Mohammad Fayaz Mohammadi; Amir Ashtari Larki
Abstract
In the March and April of 2019, a huge flood covered several provinces in the southwest of Iran and the route of these floods was finally Karun and Arvanroud rivers through Khuzestan province. The purpose of this study is to measure the current speed and direction, temperature, salinity, water level, ...
Read More
In the March and April of 2019, a huge flood covered several provinces in the southwest of Iran and the route of these floods was finally Karun and Arvanroud rivers through Khuzestan province. The purpose of this study is to measure the current speed and direction, temperature, salinity, water level, suspended sediment concentration, sediment transportation, discharge of Karun and Arvanroud rivers in flood conditions. In tidal rivers such as Karun River in Khorramshahr and Arvanroud River at the Iran-Iraq border, the tidal wave causes severe changes in flow pattern, and water level, so that requires continuous measurement over a tidal cycle (about 24 hours) to estimate a net flux of water and suspended sediment. Field measurements were performed on 5th April 2019 in spring tide in two stations in Karun and Arvanroud rivers. Analysis of the data shows that in flood conditions, water level fluctuations reduced drastically, so that the tidal range in Khorramshahr has decreased from about 100 cm to 26 cm. The average of salinity and current speed in Karun and Arvanroud stations were 0.62psu and 2.1psu, and 1.6m/s and 1.9m/s respectively. The direction of the flow, against the usual, was continuously towards the sea. The maximum suspended sediment concentration were 380g/m3 and 67g/m3 at Karun and Arvanroud stations, respectively. According to the above data, the average water discharge in Karun and Arvanroud were 2153m3/s and 7883m3/s, and the average sediment flux were 142 kg/s and 454 kg/s, respectively.
Mohammad Hossein Rezaei Moghaddam; asadollah hejazi; Khalil Valizadeh kamran; Tohid Rahimpour
Abstract
1- Introduction Floods are one of the major natural hazards that annually cause extensive damage worldwide. There are numerous floods in the northwest of the country with the beginning of spring and the start of spring rains, which in most cases results in heavy damages. Aland chai catchment suffers ...
Read More
1- Introduction Floods are one of the major natural hazards that annually cause extensive damage worldwide. There are numerous floods in the northwest of the country with the beginning of spring and the start of spring rains, which in most cases results in heavy damages. Aland chai catchment suffers from destructive floods every year since the beginning of spring. The purpose of this study was to examine and analyze the role of hydrogeomorphic indices in flood sensitivity in this basin. Hydrogeomorphic parameters of sub-basins were studied from three aspects of drainage network characteristics (including order of stream, number of streams, length of streams, frequency of stream, bifurcation ratio, length of overland flow, drainage density, drainage texture, texture ratio, infiltration number, constant of channel maintenance, and Rho coefficient), shape characteristics (Including basin area, compactness coefficient, circulatory ratio, elongation ratio, form factor, and shape factor) and relief properties (relief, relief ratio, ruggedness number, and gradient). 2- Methodology With an area of 1,147.30 km2, Aland Chai basin is located in the Northwest of Iran and in the Western Azerbaijan province. This basin is located between 38°- 30¢-14² and 38°- 48¢-22² N and between 44°- 15¢- 13² and 45°- 01¢-02² E. The minimum elevation of the area is 1093 meters and the maximum elevation is 3638 meters. This basin is one of the sub-basins of the Aras basin, which flows into the Aras River after joining the grand Qotour River. SWARA multi-criteria decision analysis model was used to weight the parameters. The Step-wise weight assessment ratio analysis (SWARA) model was developed by Keršuliene et al (2010). WASPAS multi-criteria decision-making model was used to prioritize sub-basins in terms of flood sensitivity. The weighted aggregated sum product assessment (WASPAS) method was proposed by Zavadskas et al in 2012. The WASPAS method consists of two aggregated parts, namely (1) The weighted sum model (WSM) and, (2) The weighted product model (WPM). 3- Results and Discussion Hydrogeomorphic analysis is significantly involved in the analysis of hydrological behavior of the basins. In the present study, 22 hydrogeomorphic parameters were analyzed from three aspects of drainage network characteristics, shape parameters and relief properties with the purpose of examining the effect of these parameters on the flood sensitivity of the Aland Chai basin. In the first step, the study area was divided into 15 sub-basins based on topographic and drainage characteristics using a digital elevation model (DEM) with a 12.5m spatial resolution. In the next step, the information of each sub-basin was provided based on 22 hydrogeomorphic parameters using the geomorphological laws of Horton, Schumm, and Strahler in ArcGIS software. According to the comparison among 22 parameters using the SWARA method, drainage texture, texture ratio, and drainage density (weighted as 0.273, 0.273 and 0.156) had the highest impacts on the occurrence of floods in study area respectively. On the contrary, Rho coefficient, constant of channel maintenance, infiltration number, and length of overland flow exhibited the lowest weights respectively. 4-Conclusion The purpose of the current study was to examine and evaluate the role of hydrogeomorphic indices in flood sensitivity of Aland Chai basin, for which SWARA and WASPAS multi-criteria decision-making models were employed. The results of prioritization of sub-basins using WASPAS model indicated that sub-basin 1 with a coefficient of 0.907, sub-basin 3 with a coefficient of 0.858 and sub-basin 2 with a coefficient of 0.818 had respectively the highest sensitivity to flooding. The results also revealed that sub-basins 4, 7, 11 and 15 in are placed in the high level category, sub-basins 8 and 9 are categorized in moderate-level category class, sub-basins 5, 10, 12 and 14 are classified in the low-level class and sub-basins 6 and 13 are situated in the very low level category in terms of flood sensitivity. The total area of sub-basins in the high and very high class of flood sensitivity is 656.72 km2, which comprises 57.24% of the total Aland Chai basin. Therefore, according to the findings of the study, which indicate that the study area has high flooding, it is necessary to adopt protective measures such as watershed planning and dam construction in highly sensitive sub-basins to prevent flooding and mitigate potential damages in cases of severe flooding. Keywords: Flood, Hydrogeomorphic Indices, GIS, WASPAS Model, Aland Chai Basin 5- References Keršuliene, V., Zavadskas, E. K., Turskis, Z. (2010). Selection of rational dispute resolution method by applying new step-wise weight assessment ratio analysis (SWARA), Journal of Business Economics and Management, 11(2), 243–258. https://doi.org/10.3846/jbem.2010.12. Zavadskas, E.K., Turskis, Z., Antucheviciene, J., & Zakarevicius, A. (2012). Optimization of weighted aggregated sum product assessment. Electronics and electrical engineering, 122(6), 3-6. http://dx.doi.org/10.5755/j01.eee.122.6.1810
Zohreh Maryanaji; Abozar Ramezani
Abstract
1- Introduction Natural hazards cause enormous damages every year. Among the natural hazards, floods, earthquakes, and droughts have special importance in financial and human losses. Meanwhile, according to the available statistics and information, floods in some parts of the world, especially in Asia ...
Read More
1- Introduction Natural hazards cause enormous damages every year. Among the natural hazards, floods, earthquakes, and droughts have special importance in financial and human losses. Meanwhile, according to the available statistics and information, floods in some parts of the world, especially in Asia and Oceania, have the highest damage. Iran is one of the arid and semi-arid regions of the world with particular climatic conditions. Inappropriate spatiotemporal distribution of rainfall in such regions has caused devastating floods. In this study, flood vulnerable areas are identified by determining the effective parameters of flood using Shannon entropy model. The results of this study can be used in flood zoning and forecasting and planning and management of water resources in the region. 2- Materials & Methods In multi-criteria decision-making problems having and knowing the relative weights of the existing indicators is a significant step in the problem-solving process. (Relations 1 to 6). (1) Aij= (2) (3) (4) Ej= i=1,2…,m (5) wj=dj/∑dj (6) wj= Entropy method is one of the multi-criteria decision-making methods for calculating the weight of criteria. This method requires a criterion-option matrix. The steps of Shannon entropy method consist of five steps of the decision matrix, normalization of the decision matrix, calculation of the entropy of each index, the calculation of deviation, and calculation of weight value Wj. In the Shannon method using the experience and knowledge of experts appropriate factors are determined and weighed. After collecting the questionnaire data and considering the geography of the study area, the scores of each factor are adjusted. 3- Results & Discussion Natural parameters of flood occurrence in Hamadan province include: climate, snowmelt, slope, soil type, Gravilius coefficient, and vegetation. Due to the climatic characteristics of the province, most of the province's rainfall is due to the Mediterranean systems. In winter, the rains are in the form of snow, and in the early spring the melting of snows is accompanied by spring rains which most of the time causes the rivers to overflow. Due to the severe destruction of vegetation in the province, the potential of the region in flooding has been increased. In general, it can be said that the occurrence of floods in any region is due to the confrontation and alignment of human and natural factors. This study only examines the natural causes of flood. The study of the effect of each parameter in the occurrence of floods based on the data-expert method showed that the six factors studied in these studies do not have the same effect on reducing or increasing floods in the basins. 4- Conclusion Based on scoring the natural factors that cause floods, according to the intensity of their impact, the flood-prone areas of the province have been identified. Based on the combined data model and Shannon entropy, the highest weighting was given to the maximum 24-hour precipitation. Vegetation factors, snow melting time, basin slope, soil type and Gravilius coefficient were identified as the most effective natural factors in causing floods in Hamadan province, respectively. Based on the final weights, a hazard map was drawn using the GIS. According to the hazard map, the very high risk regions are located in the central and southern parts of the province. Also, the northern areas including the cities of Razan, Kaboudar Ahang and Dargazin are located in high risk area. Using the results of this study, it is possible to identify the approximate time of flood occurrence and flood-prone areas in Hamedan province.
Sayed Meysam Davoudi; Reza Ghazavi
Abstract
1- Introduction The strategic management and planning is the highest level of management that has a long-term attitude in resource allocation and decision making. Relying on a combination of perspectives, policies, structures, and effective systems in this field, the strategic approach in water resources ...
Read More
1- Introduction The strategic management and planning is the highest level of management that has a long-term attitude in resource allocation and decision making. Relying on a combination of perspectives, policies, structures, and effective systems in this field, the strategic approach in water resources management prevents sudden future events and crises that will lead to the sustainable development of water resources (Pour Fallah et al., 2009). Determination and development of water resources are one of the important steps in sustainable use of water resources. There are several methods and models for this purpose, each of which contains its own concept and insight and follows specific techniques and instructions. Among the various models, the SWOT matrix, which assesses the system strengths, weaknesses, opportunities, and threats, is more common and well-known (Hill and Vetbrook, 1997). Extraction of a strategy based on the strengths and weaknesses of the internal environment and the opportunities and threats outside the management field provides realistic solutions to the decision maker, and the closeness or distance of the solutions from the sustainable development model - planning (Azarnivand et al., 2013). Although the common use of this model is mainly related to the strategic planning of production and service organizations, its unique features make it possible to use it in the analysis of various issues such as watershed management at extra- organizational levels. More recently, the use of SWOT analysis for water resources management has been proposed in previous research (Petusi et al., 2017; Negar, 2015). 2 -Methodology This study was performed in four main stages, namely identification of internal and external factors, weighting of factors, creation of matrix for the evaluation of internal and external factors, and finally selection of appropriate strategies (Ghazavi, 2019). The formation of SWAT matrix leads to the presentation of four management strategies as follows. • Competitive/Aggressive Strategy (SO): By implementing this strategy, an effort is made to take advantage of external opportunities. • Review/Conservative Strategy (WO): The goal is to take advantage of opportunities in the external environment to improve internal weaknesses. • Diversity Strategy (ST): Reduce the impact of external threats using strengths. • Defensive Strategy (WT): Defensive mode that aims to reduce internal weaknesses and avoid external threats (Sarai and Shamshiri, 2013) 3- Results and discussionAccording to the results of the present study, the total final score of internal factors was 2.98 in the evaluation matrix, which can mean the strength of internal factors. The total final score of external factors was 2.89 in the evaluation matrix, which means that Natanz city has been able to take advantage of the factors that create opportunities or situations, or avoid some of the factors that threaten the city. Based on the results, the best strategic position for Natanz urban watershed is in the offensive range, which focuses on internal strengths and external opportunities. Besides the existing capabilities and potentials in Natanz should be used in managing runoff management. 4- Conclusion In order to provide appropriate strategies and strategies for strategic management of Natanz urban watershed, strengths, weaknesses, opportunities, and threats were studied using the SWOT method. The findings show that Natanz city, despite a low level of the urban basin for various reasons, was not able to make optimal and desirable use of this natural facilities for its development and progress. The existence of impenetrable levels, digging numerous wells to supply water to factories and industries, and the lack of municipal wastewater treatment plants are some of the threats to the region. According to the results, aggressive strategy is the best structural strategy for the Natanz urban watershed.
Sanaz Daei; Meysam Salarijazi; Khalil Ghorbani; Mahdi Meftah Halaghi
Volume 5, Issue 17 , March 2019, , Pages 145-163
Abstract
Introduction
There are many models for flood prediction that are based on different conceptual bases. The standard SCS-CN method was developed in 1954 and it is documented in Section 4 of the National Engineering Handbook (NEH-4) published by Soil Conservation Service (now called the Natural Resources ...
Read More
Introduction
There are many models for flood prediction that are based on different conceptual bases. The standard SCS-CN method was developed in 1954 and it is documented in Section 4 of the National Engineering Handbook (NEH-4) published by Soil Conservation Service (now called the Natural Resources Conservation Service), U.S. Department of Agriculture in 1956. The document has been revised several times. It is one of the most popular methods for computing the volume of surface runoff for a given rainfall event from small agricultural, forest, and urban watersheds. The method is simple, easy to understand, and useful for ungauged watersheds. The method accounts for major runoff producing watershed characteristics, viz., soil type, land use/treatment, surface condition, and antecedent moisture condition. Recent researches focus on the improvement of this model and improve its efficiency but it is necessary to evaluate the improved models for Iran's watersheds. The purpose of this study was the comparison of standard SCS-CN and developed three parameter Mishra-Singh models for flood hydrograph and peak estimation using data of five watersheds in Golestan Province.
Methodology
Study Area and Used Data
Five watersheds (including Galikesh, Tamer, Kechik, Vatana, and Nodeh) located in Golestan Province were considered to evaluate different models for flood hydrograph estimation. The characteristics of the selected watersheds are different. For Tamer, Galikesh, Kechik, Nodeh, and Vatana watersheds, the areas are equal to (1527, 401, 36, 790 and 11 km2), the parameters are (289, 139, 26, 208 and 20 km), the mean altitudes are (1131, 1358, 928, 1540 and 899 m), the mean slope of the watersheds are (19, 27, 19, 28 and 33%), the length of the main channels are (94, 58, 10, 66 and 8 km), and the number of rainfall-runoff events are (10, 13, 3, 9, and 4 cases).
Descriptions of Models
The standard curve number (SCS-CN) model was based on the following basic equations:
(1)
(2)
P is total rainfall, Q is excess rainfall, CN is curve number, Ia is initial abstraction, and S is maximum retention.
Using the concept of the degree of saturation (C=Sr), where C is the runoff coefficient (= )), Mishra and Singh (2002) and Mishra et al. (2006) modified the original SCS-CN model after the introduction of antecedent moisture Mas:
(3)
The relationships developed by Mishra et al. (2006) for Mare:
(4)
(5)
P5 is prior 5-day rainfall depth.
Three model accuracy criteria including root mean square error (RMSE), Nash-Sutcliff efficiency (NSE) and percentage error in peak (PEP) were applied to compare the results of models (Adib et al., 2010-2011).
Results
There were 39 rainfall-runoff events, of which 25 and 14 events were respectively selected for the calibration and validation steps. The parameters of investigated models for different events and watersheds and related model accuracy criteria were calculated. The root mean square error (RMSE) and Nash-Sutcliff efficiency (NSE) criteria can be used for the analysis of the flood hydrograph simulation while percentage error in peak (PEP) criteria is suitable for the analysis of the flood peak discharge simulation. In the Gallikesh watershed, for the developed three parameter Mishra-Singh and standard SCS-CN models, the RMSE criteria values were (16, 11.05, 2.8, and 10.63) and (17.94, 14 , 6.56 and 13.56), the values of NSE values were (-0.88, -84.44, -0.9 and -4.77) and (-1.37-, -1.38, -9.7, and -8.4), and the PEP values were (0.4, -1.4, 0.55, -0.3) and (0.24, -2.11, -1.39 and -0.62). For the Nodeh watershed in different events, the RMSE criteria values were (13.22, 23.57, 79.53 and 68.15) and (11.83, 22.74, 88.96 and 69.92), the NSE values were (-6.88, -2.7, -0.17 and -66) and (-5.31, -2.46, -0.46 and -69.5), and the values of PEP were (-1.19, -1.98, 0.83, -2.48) and (-1,-2.4, 0.99 and -2.57) for the developed three parameter Mishra-Singh and standard SCS-CN models were calculated. In the Tamer watershed for two models of developed three parameter Mishra-Singh and standard SCS-CN, the values of different criteria estimated as the RMSE criteria values were (13.04, 26.85, 5.9 and 19.26) and (12.04, 92.62, 5.26 and 48.81), the values of NSE criteria were (-0.92, -20.3, -4.9 and -0.14) and (-0.73, -252.5, -3.75 and -6.37), and the PEP criteria values were (0.52, -0.2, -0.8, and 0.62) and (0.62, -5.14, -0.74 and 1.09). In Vatana and Kechik watersheds for the developed three parameter Mishra-Singh model different criteria were calculated as the RMSE values (2.5) and (1.5), the NSE criteria values (0.51) and (-0.07), the PEP criteria values (0.45) and (-0.3). However, in these two watersheds for the SCS-CN standard model, the RMSE criteria values were (4.8) and (2.91), the NSE criteria values were (-0.82) and (-2.93) and the PEP criteria values were (0.95) and (0.6).
Discussion and Conclusion
The values of root mean square error (RMSE), Nash-Sutcliff efficiency (NSE) showed that the developed three parameter Mishra-Singh model improved the accuracy of the flood hydrograph estimation relative to the standard SCS-CN model for 71% of the studied events and the difference between two models for remaining 29% event was negligible. Also, the values of percentage error in peak (PEP) revealed that the three parameter Mishra-Singh model led to a decline equal to 78% in flood peak estimation in comparison with standard SCS-CN model application. In addition, the standard SCS-CN and the three parameter Mishra-Singh models were respectively 64% of and 57% of the studied cases. In this study, the accuracy of the standard SCS-CN andthedeveloped three parameter Mishra-Singh models compared the flood hydrograph and peak estimation considering data of five watersheds in Golestan Province. The investigation of the model accuracy criteria revealed that the developed model led to a considerable improvement of flood estimation in studied watersheds.
Amir Hossein Halabian; shamsolah Asgari
Volume 4, Issue 12 , December 2017, , Pages 153-177
Abstract
Extent Abstract Introduction One way to decrease flood damage is to zone the potential of flood in watersheds. In other words, separating the flooding areas and determining the effective factors in flooding can play a special role in preparing a suitable medium and long term policy making for optimal ...
Read More
Extent Abstract Introduction One way to decrease flood damage is to zone the potential of flood in watersheds. In other words, separating the flooding areas and determining the effective factors in flooding can play a special role in preparing a suitable medium and long term policy making for optimal exploitation of lands. Some of the studies which were based on zoning the potential of flooding worldwide and Iran includes Hawkins (1979), James et al. (1980), Bales et al. (1981), Enayat Rasoul et al. (1994), Suwanwerakamator (1994), Singh (1997), Francisco et al. (1998), Stephen (2002), Sinnakaudan et al. (2003), Sanyal and Lu (2004), Levy (2005), Meyer et al. (2009), Cook et al. (2009), Qin et al. (2011), Bakhtyari Kia et al. (2011), Al-Ghamdi et al. (2012), Ismail et al. (2013), Demir and Kisi (2016); in Iran: Qaemi and Morid (1375), Qanavati and Farajzadeh (1379), Abdi and Rasouli (1380), Omidvar et al. (1389), Malekian et al. (1391), Lajevardi et al. (1392), Nasrinnejad et al. (1393). In this research, Mishkhas watershed was studied in terms of flooding potential using multivariate statistical methods of factor and cluster analysis and geographical information system (GIS). Finally, the watershedflooding map was drawn in three classes of low, moderate and high. Zoning the flooding potential in this watershed can help reduce the damage caused by this natural hazard. Such studies can be a basis for future planning of regional and local developments. Methodology One of the appropriate criteria for understanding the potential of flooding in basins is classifying them according to geometry, physiography, permeability, and climatic criteria. In this study, the topography maps of geographic organization (1:50000), and the geological map of vegetation (1:250000), land use, soil maps of Ilam province (1392), precipitation data, and multivariate statistical methods of factor and cluster analysis have been used. In this research, Mishkhas watershed was divided into 12 sub-watersheds and their flooding intensity was classified into 3 classes. According to the aim of the research, the maximum instant debit, daily precipitation, and the date of watershed floods during the statistical period were selected. In addition, the effective criteria in watershed flooding was calculated using ArcGIS software including geometry, physiography, permeability, and climatic parameters for Mishkhas sub-watersheds. Then, they were analyzed using factor analysis and 28 parameters were summarized in the form of 5 main factors (form, stream, slope, drainage, and runoff). Finally, the intensity of the sub-watersheds' flooding were c 3 high, moderate, and low classes according to the mentioned criteria. Discussion In this research, the total criteria which were used were operating by a type R factor analysis. The results of this research decreased 28 initial criteria to 5 superior factors including (1) form, (2) stream, (3) slope, (4) drainage, and (5) runoff. According to calculations done on the criteria in the first factor, sub-watersheds 1, 2, 3, 5, 9, 11, and 12 with the highest flooding, sub-watersheds 6, 8, 10 with moderate flooding and sub-watersheds 4 and 7 with the lowest flooding intensity were identified. The first factor indicated the reverse relationship between the watershed's form and flooding intensity. That is, the more its length and area, the less its flooding intensity. In the second factor (stream) it was specified that sub-watersheds 1, 10, 3, and 12 have high flooding, sub-watersheds 7, 8, 5, 2, and 9 have moderate flooding, and sub-watersheds 11, 4, and 6 have low flooding. It was also indicated a reverse relationship between stream density and flooding intensity. In the third factor (slope), it was specified that sub-watersheds 6, 5, 1, 9, 10, and 11 have high flooding intensity, sub-watersheds 2, 4, and 8 have moderate flooding intensity, and sub-watersheds 7 and 12 have low flooding intensity. The sub-watersheds with high flooding intensity are located in northeastern and eastern parts of the basin which are mostly mountainous and have high height difference and slope. Sub-watersheds with low flooding intensity have little height difference, low slope, and relatively suitable vegetation. The calculations done on the fourth factor (drainage) indicated that sub-watersheds 12, 7, 4, and 2 have high flooding intensity, sub-watersheds 5, 6, 10, and 11 have moderate flooding predisposition, and sub-watersheds 1, 3, 8, and 9 have low flooding predisposition. Sub-watersheds with high flooding have been operated as the main drain of watershed. The results indicated that 33% of sub-watersheds have high flooding in terms of drainage factor. According to calculations done on the fifth factor (runoff) sub-watersheds 12, 3, 4, and 5 have high flooding intensity, sub-watersheds 1, 2, 6, and 8 have moderate flooding intensity and, sub-watersheds 7, 9, 10, and 11 have low flooding intensity. According to the factor's score, Mishkhas watershed is divided into three high, moderate, and low flooding classes and the zoning map of sub-watersheds' flooding intensity has been prepared. Conclusion In this research, factor analysis and cluster analysis were used for studying the flooding intensity of Mishkhas watershed and the role of sub-watersheds in flooding of this area. According to factor analysis results, 28 initial criteria reduced to 5 factors including form, stream, slope, drainage, and runoff. Analyzing the factors indicated that sub-watersheds 3, 5, 8, and 9 in form factor, sub-watersheds 1, 6, and 11 in slope factor, sub-watersheds 2 and 7 in drainage factor, and sub-watersheds 4, 12, and 10 in runoff factor have extra flood hazard intensity. Sub-watersheds were divided into 3 groups including high, moderate, and low flood producing based on the similarity of flooding intensity, erosion, vegetation, and human activities. For separating the sub-watersheds in homogenous groups, three homogenous groups were identified after data standardization by a standard model and applying Euclidean distance and Ward method. The first group's sub-watersheds 1, 2, 3, 4, 5, and 6 have high power to produce run off because of having high height and slope, low vegetation and permeability, and high flooding capacity. The second group's sub-watersheds 7, 8, 11, and 12 have high power to produce runoff, because of high slope, low vegetation, high height, low permeability, and high flooding power. In the third group's sub-watersheds 9 and 10, the flow was decreased because of decreasing the slope and increasing the permeability, so they indicated lower power to produce runoff. In fact, sub-watersheds play fundamental roles in flooding of this watershed that affect large downstream agricultural lands.
Asadollah Hejazi; Sogra Andariani; Farhad Almaspour; Abolfazl Mokhtari Asl
Volume 2, Issue 3 , January 2017, , Pages 61-80
Abstract
Flood is the main destructive phenomena in Iran which causes human casualties and financial damages every year. The purpose of this research is to define flood susceptible zones in Ligcanchai Catchment. To achieve this end this study provided different information layers such as slope, elevation, ...
Read More
Flood is the main destructive phenomena in Iran which causes human casualties and financial damages every year. The purpose of this research is to define flood susceptible zones in Ligcanchai Catchment. To achieve this end this study provided different information layers such as slope, elevation, soil hydrological units, curve number, runoff height, lithology, land use and landcover, hydrography density, compactness coefficient of 23 basins by using maps, reports, satellite images and field studies. All layers were then weighted with criteria and sub criteria. The study used the hierarchical method to weight criteria and fuzzy logic to weight sub criteria. Then 5 flood susceptible zones were defined by using multi-criteria evaluation and linear combination was weighted. The results show that around 28 percent of the Catchment has high and very high flood risk and that these areas are located near Tabriz city. Since flood events destroy the infrastructures and cause human casualties every year, substantial actions must be taken to prevent the high and very high flood risks. These activities must be planned in the integrated watershed management plans, and the flood risk management in order to improve the watershed vegetation in the watershed to minimize financial damages and human life losses.
Mousa Abedini; Mohammad Hossein Fathi
Volume 2, Issue 3 , January 2017, , Pages 99-120
Abstract
Flood is one of the most common natural worldwide hazards that causes enormous losses of life and property throughout the world. Therefore, the development of flood mapping forecast models is curial in decision making before the flood and for the after flood management. The aim of this study is to determine ...
Read More
Flood is one of the most common natural worldwide hazards that causes enormous losses of life and property throughout the world. Therefore, the development of flood mapping forecast models is curial in decision making before the flood and for the after flood management. The aim of this study is to determine the flood hazard zones in the khiav Chai basin using the network analysis process. To implement this model in the area under study, various data such as rainfall, land use, slope-morphological characteristics such as convexity (profile curvature) convergence divergence slopes (plan curvature), steep slopes, vegetation index (NDVI), distance from major rivers and drainage network density were considered. The results obtained from the network Analyzer model shows the fact that more than 15 percent of the area affected by the floods with very high potential risk of occurrence are mainly located at the bottom of the basin. These levels are often less than 35% in slope, with low vegetation density profiles, converged areas with concave surfaces, and areas near rivers. Analysis of the final weights derived from the AHP in relation to flood risk shows that the slope of the geological formations operating by 0/99, and 0/822 value, have the highest impact and influence, regarding the high degree of control and influence they have on the amount of runoff and discharge of the surface area. The importance and influence of the SPI with 0/226 and 0/065 STI are of less important compared to other factors.
