Ezzatollah Ghanavati; Ali Ahmadabadi; Mansour Sadeghi
Volume 6, Issue 18 , June 2019, , Pages 139-159
Abstract
IntroductionA flood is an exceptional stream that may be flooded from the natural bed of the river. Usually, the maximum observed discharge during a year is named a flood or an annual flood. It is one of the natural disasters which has the highest damage in the world, after an earthquake. Losing life, ...
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IntroductionA flood is an exceptional stream that may be flooded from the natural bed of the river. Usually, the maximum observed discharge during a year is named a flood or an annual flood. It is one of the natural disasters which has the highest damage in the world, after an earthquake. Losing life, land, and property, especially along the river, are among its most perilous environmental hazards. A comprehensive flood management seeks to use structural and non-structural methods to prevent flood intensity and minimize its human and financial losses. Although we can minimize their damage, there is not any possibility of controlling floods. Qomroud Basin with an area of 3563 km2 (356300 hectares), is located in provinces of Markazi and Qom and in a geographical position of 50° 2 33 to 50° 54 29 East and 33° 57 37 to 34° 39 28 north latitude. Its minimum and maximum heights are respectively 964 m and 3145 m and its average slope is 13.6 %. The perimeter of the basin is 452.7 km and is part of the main catchment area of Iran's central plateau. After several destructive floods with significant damage in recent years, especially after the huge flood of April 2009, the need for desirable flood management in the Qomroud River basin is very urgent.MethodologyThe purpose of this research was to control the floodwaters of the Qomroud Basin by determining the appropriate flood conservation areas using a multi-criteria decision-making technique. Flood diversion and storage is a well-known method for dealing with the risks and damage of a flood. It can also improve the quality and quantity of underground water. In fact, flood control and artificial feeding of aquifers are among its important results. The Weighted Aggregates Sum Product Assessment (WASPAS) model is a new multi-criteria decision-making technique (MCDM) that was introduced in 2012 and can be effective in complex decision-making issues. It is based on the combination of two models of multi-criteria decision making WSM (weight aggregate model) and WPS (weighted production model) and is more accurate and has the ability to rank. Its application has four stages. In this hybrid model, it has been attempted to use a combined benchmark to determine the final importance of each option, which combines the parity contribution from WSM and WPS for the final evaluation of the options. In this study, the variables of gradient, soil, land use, groundwater depth, landform, surface permeability, roughness, accumulation flow index, lithology, elevation, and drainage density as effective factors in location for diversion and flood storage were used. The model (WASPAS) which is one of the most recent multi-criteria decision-making models was used to calculate the indicators' weights and rank the options and prepare the final map.ResultThe results obtained through this model have identified the areas susceptible to flood storage, with high accuracy and in the least possible time. Scoring each criterion is based on their relative importance. After determining the score of each criterion, a multi-criteria evaluation of the GIS was obtained using the overlapping operation, WASPAS model, and the final map (synthesis) of land potential relative to the flood reserve. The relative heights of slope and land use were respectively 0.136, 0.12. The relative weights of the height and the density of drainage were respectively 0.06 and 0.04, with the least importance for zoning susceptible flood reservoirs.Discussion and conclusionBy combining their results with the WASPAS model, it was possible to identify the susceptible areas to storm-storing with high precision and in the least possible time. The results showed that the Qomroud basin was divided into five classes including very high with 24 percent, high with 28.2 percent, moderate with 24.9 percent, low with 15.2 percent, and very low with 7.7 percent. Thus, there were nine very suitable areas found in the central, south, northwest and eastern parts of the basin for flood diversion and storage. The aforementioned areas were also recognized for field purposes for the desired purposes.
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.
