Nezam Asgharipour Dasht Bozorg; Mohammad Reza Servati; Pervez Kardavani; Siavash Shayan
Volume 5, Issue 17 , March 2019, , Pages 65-84
Abstract
Introduction
Alluvial fans have a great importance in terms of their high efficiency to create natural aquifer and groundwater storage. Increasing the rate of water demand and relying on groundwater has caused a remarkable decline in groundwater resource and aquifer level. On the other hand, flood spreading ...
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Introduction
Alluvial fans have a great importance in terms of their high efficiency to create natural aquifer and groundwater storage. Increasing the rate of water demand and relying on groundwater has caused a remarkable decline in groundwater resource and aquifer level. On the other hand, flood spreading is known as an applicable and an effective method for artificial aquifers recharging in arid and semiarid regions. Sabzab and Gotvand plains (fig. 1), in Khuzestan Province, have experienced vivid decline in groundwater-level due to over pumping of aquifer resources, since last decades. Therefore, these plains have been selected to implement methods of artificial recharging of groundwater, especially flood spreading.
Methodology
The research methodology included comprehensive methods of field observations, application of ArcGIS, 10.3 tools, and modeling. Accordingly, a geographical information system was used for the zoning of the suitable areas to implement artificial recharging by a flood spreading method based on the fuzzy logic model. Imported data for zoning included Landsat ETM+ satellite images (2010, 28.5 m resolution), topographic maps of Gotvand and Sarbishe regions (1:25000 scale), geological map of Dezfol region (1:100000 scale), precipitation data, soil permeability data, and the measurement of the electrical conductivity of floods region. The zoning procedures provided 6 GIS-ready map layers including quaternary deposits of the region, slope, infiltration, electrical conductivity, thickness of alluvium, transmissivity, and drainage density. In the second step, the effective factors were formulated in a fuzzy manner and GIS-Ready layers were overlapped using Sum, and, OR, Product, and Gamma operators. Finally, the zones with high suitability for flood spreading were overlaid over the alluvial fans outcrops.
Results and discussion
Several thematic maps were produced on the basis of the fuzzy method. The suitability zoning as the main objectives of the research was obtained in four classes ranged (fig. 5) from high suitable to unsuitable (table 1). The results showed that high-suitable areas were often at the bottom of the Bakhtiari conglomerate formations and alluvial fans (Fig. 7). In addition, alluvial fans which had mainly composed of coarse size sediments had close genetic relationship with Bakhtiari conglomerate formation and represented the remarkable matching with two high-suitable and suitable classes. The mean rate of 83 % of the different fuzzy operators showed the most comparability with high suitable and suitable areas.
Conclusion
The research hypotheses were successfully confirmed by the resultant data. The present research indicates the importance of geomorphological landforms in terms of artificial groundwater recharge and it should be protected as a source of water. Therefore, incorrect changes to this lands form should be avoided. Furthermore, the fuzzy method has represented a useful manner to find suitable zones for flood spreading. The research method is also recommended to be used in other similar geological conditions in Khuzestan Province.
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.
Mojtaba Yamani; Abolghasem Goorabi; Shirin Mohammadkhan; Hamid Ganjaeian
Volume 4, Issue 12 , December 2017, , Pages 1-23
Abstract
Introduction Qorveh, one of the cities of Kordestan province, has high amount of precipitation and, consequently, a significant resource of water. Geological surveys, physiography and hydrology, and in particular field studies, have revealed rivers' significant role and influence on the formation ...
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Introduction Qorveh, one of the cities of Kordestan province, has high amount of precipitation and, consequently, a significant resource of water. Geological surveys, physiography and hydrology, and in particular field studies, have revealed rivers' significant role and influence on the formation of human activities and settlements. Unfortunately, much of the locally carried out planning has ignored hydro-geomorphological factors. In addition, population growth and the growth in residential and industrial areas have caused uneven progress of the residential areas towards the riverside which has, consequently, changed the natural shape of the river such as its width, length, slope, sediment, and the like. These problems shows the importance and necessity of thorough hydro-geomorphological studies. Therefore, the main objective of this study was to investigate the hydro-geomorphological status of the Shoor River's basin and evaluate the its lands' capabilities to develop urban areas, determine the optimum location based on hydro-geomorphological criteria, minimize the undesirable impacts of inhabitants of cities and villages on the highlands, especially the catchment areas, and minimize the harmful effects of the environmental hazards on agricultural products and inhabitants. Materials and methods The study is based on field, library, and software methods. Firstly, using the topographic maps, the study area of the basin was specified. In this study, 8 factors of lithology, faults, slope, aspect, elevation, distance from the river, vegetation, and land use were used in order to evaluate and zone suitable areas for urban development of Qorveh. After the preparation of the information layers, the coefficients and their values were estimated by the use of ANP model. In this model, like AHP, the measurement of the amount of the relative importance is done by pairwise comparisons with the help of the range of 1 to 9. Number 1 represents the equal importance of two factors and 9 represents the extreme importance of one factor over the other. To this end, for each model, a total of 15 questionnaires were distributed among specialists (5 Land use planning, 5 urban planning, and 5 geomorphology specialists) to rate each of the factors. After analyzing the questionnaires, to calculate the final weights of each criteria and subcriteria (according to the internal relations), Super Decisions software was used for the ANP model. Then, indicators and variables affecting urban development, using the Fuzzy function, were sub-Fuzzed and all layers of the study were standardized and compared. The coefficients were transmitted to the GIS polygonal descriptive databases to make them more quantitative and comparable. Finally, the final maps were made by overlaying the information layers maps. Discussion and results In the present study, to locate suitable areas for urban development, 8 factors were used and the classification was done. On this basis, the suitable areas for future development of the city have a slope of less than 11 %, the lithology persistent for building, low elevation, barren land use, and the changeable vegetation. In addition, they are distant from the fault lines and they are near the riverside. Additionally, the map of each criteria was prepared and the final map was obtained by combining the information layers, based on the weight obtained through ANP. Conclusion The ANP Model, because of having features such as simplicity, flexibility, simultaneous use of qualitative and quantitative criteria and final ranking of the options, can provide a suitable framework for analyzing the issue and determining the final ranking of the options. However, since allocating evaluation weights cannot provide enough reliability, the use of fuzzy logic, for more integration between layers and fixing possible errors, is needed. Finally, the study area was divided into five regions in terms of available potential and the ability for the purposes of the urban development. According to the criteria which was considered in this zoning, it can be said that, areas with the highest score, are located in ideal areas and away from danger. However, it should be noted that the significant presence of the geomorphologic phenomena, such as Bader and Parishan mounts in the southern parts of the study area, as well as the existence of faults in the southwest and southeast of the area have caused the basin to be in a very inappropriate class in relation to the development of the space. The results of this study indicate that the Shoor River's basin has a high potential for spatial development and urban planning in the future.
Ezzatollah Ghanavati; Feridoun Babaee Agdam; Taher Hemmati; Masoud Rahimi
Volume 2, Issue 3 , January 2017, , Pages 121-135
Abstract
Khiav Chai basin is located in Ardabil province as the sub basin of Gharasou basin. The
main river of this basin is Khiav Chai basin originating from the Sabalan Mountain,
which after passing through the Moeil valley flows into Gharasou River. Since the
Meshkin Shahr city is located downstream of ...
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Khiav Chai basin is located in Ardabil province as the sub basin of Gharasou basin. The
main river of this basin is Khiav Chai basin originating from the Sabalan Mountain,
which after passing through the Moeil valley flows into Gharasou River. Since the
Meshkin Shahr city is located downstream of this basin and is facing the frequent
danger of flooding, there should be special attention to prevent the flooding risk in this
area. This study focuses on the zoning potential floods in Khiav Chai basin using the
Fuzzy logic. To achieve this end, 8 parameters are used in this study including
vegetation density, drainage density, distance from drainage, lithology, land use,
rainfall, altitude and slope. In this model, all the layers with raster format were uploaded
into the Arc GIS software. Then the layers were fuzzified according to their functions.
In the next step, using different Fuzzy model functions, the zoning of the flooding of the
basin was completed. The results showed that the valleys, thalwegs with concave
slopes, and downstream areas were the most effective watershed areas in preventing
flood hazards. The results of this research can help reduce the loss of life and property
in downstream residential parts in the area, and can also be used as a basis for further
studies in relation to natural hazards.
