Abolghasem goorabi; Mojtaba Yamani; Seyyed Javad Hoseini
Volume 5, Issue 16 , December 2018, , Pages 81-100
Abstract
Abstract
Introduction
Rivers' pattern is seldom stable and is always subject to change. Rivers' banks have long been the most important areas of population settlement, especially in the semi-arid regions of Iran. This has made the recognition and assessment of the geometric deformation of rivers an ...
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Abstract
Introduction
Rivers' pattern is seldom stable and is always subject to change. Rivers' banks have long been the most important areas of population settlement, especially in the semi-arid regions of Iran. This has made the recognition and assessment of the geometric deformation of rivers an important applied topics. Alluvial beds of a river are divided into two groups of stable and unstable. While in a stable bed, the walls and the floor are stabilized, in the unstable bed, the walls and the floor are not constant and have a changing state. Zanjanrood is regarded as the natural bio-economical artery of Zanjan province. In the present study, by recognizing the temporal and the spatial hydro-geomorphological changes of Zanjanrood during the years 1955 and 2011, and in the western part of the river, which is more important for agriculture, the amount of morphological changes is calculated and presented in the form of a map.
Methodology
The method of the study was analytical by spatial-local comparison based on the direct and the indirect observations using satellite images, aerial photos, and maps.
In this method, the intervals were classified into distinct parts based on the morphology-hydrodynamic similarity. Then, by applying spatial analysis on the raster maps, the pattern and variation of the changes were estimated by plotting tangential transects on the extension and restriction areas in the right and left sides. By determining the extension and restriction areas in river sides, the type and amount of stream’s variation in various reaches was determined. Afterwards, the total areas of extension and restriction on both sides of the stream were computed. Transects are rectangles with constant angles whose area variations indicate the changes of the river banks in different time ranges. This technique was used to determine the area dominated every progression and regression area in order to analysis and assess of the main factor(s) affecting this change.
Result
The results of the study showed that the outcome of the action-reaction of the factors affecting Znjanrood changes in the studied area had been a stable trend over the past 56 years. The most important factors involved in this trend were the development of the agricultural activities, the increase of management actions to stabilizing the river for agriculture and infrastructure proposes, and dam construction. However, the effect of slope and geological conditions (neo-tectonic) should not be neglected as well.
Discussion and conclusion
The results indicated that the overall trend was to reduce the width of the channel to its axis. However, the process has increased from the first period (1955-1985) to the second (1985-2011) and the third periods (1985-2011), so that at the end of the given time intervals, there was an increase in the relative stability of the stream. The change in flow to the outlet reduced the erosion power of the river flow and increased the stability and relative stabilization of the bed. The development of the fairly stable gardening activities dispersed on the flood bed played an important role in the stability of the stream in the studied area, so that the gardens and fields on the stable river main bed sides exhibited great changes in the images and photographs.
The role of the human factors in the Zanjanrood Basin due to its relative geographical position (east to northwest transit), has been the basis for the development and launch of several road construction projects (railways, roads and freeways) during the period of 1955 to 2011 in Zanjanrood and caused the change of Hydro-geomorphological-Hydrodynamic systems. A quantitative assessment of the Zanjanrood river bed changes shows that the rate of change, overcoming the general trend of stability and stabilization, has increased from the first period to the last period. Indeed, while the stabilization rate in the first period was 0.16 km2, in the second and final periods, it was respectively 1.91 and 2.01 km2. Progressions are concentrated in the beginning and end of the research (Transects 1, 2, 6, and 9 to 13), which affects the lands of the villages of Nikpey, Darelik, Dolanab, Naji, Idalou, and Baghloja and Saifabad. The recessions are also focused on transects 3 to 8, excluding transect number 6. Based on the results, Zanjanroud shows the overall stability trend. The adjacent area of the upper and lower parts of the studied research (the areas around the villages of Nikpey and Baghloja) are among the most sensitive areas of the research.
Mahmood Alaei Taleghani; Najmeh Shafiei; Marzyeh Rajabi
Volume 4, Issue 13 , March 2018, , Pages 21-41
Abstract
Introduction Groundwater resources, due to being sweet and having chemical compounds, fixed temperatures, lower pollution rates, and higher levels of reliability in supplying water resources, are considered as reliable resources, especially in arid and semi-arid regions. In addition, due to the ecological ...
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Introduction Groundwater resources, due to being sweet and having chemical compounds, fixed temperatures, lower pollution rates, and higher levels of reliability in supplying water resources, are considered as reliable resources, especially in arid and semi-arid regions. In addition, due to the ecological potential of the region, it is an important and effective phenomenon in the economic development, ecological diversity, and community health. Relying on groundwater resources, especially in dry and semi-arid lands, has led many scholars to study how to form or access them. The main objectives of this research are to investigate the effective role of geomorphologic factors in the potential of underground water resources in the region and the possibility of proper management of water resources in the studied basin and to be more knowledgeable about groundwater issues,. Therefore, studying and identifying the hydro geomorphology of the area and the factors affecting the aquifers is essential. The study area is located in the geographical boundary of the west of the country in the northeast hillside of the Zagros range. The area of Meiandareh, with an area of 329 km2, is located in the northern part of Kermanshah Province. Methodology The method used in this research was based on the analytical and weight-empirical analysis carried out in separate steps. First, an inferential method was used to determine the direction and amount of groundwater flow, the role of nutrition of various geomorphological phenomena in the plain, the position of the piezometer wells, and the groundwater level map for the plain. Second, weighing index based on expert opinion and expert of Delphi-completed questionnaire of various weighted layers were used. Finally, the potential of the plain and its favorable regions were studied using the pairwise G.I.S. software. Discussion In the maps of the groundwater level of the plain, it was indicated that while the maximum level in the eastern margin of the eastern part of the region at the beginning of the apple flank was about 25 m, in the boundary of the Ghareh Souz River and flood plains, it was about 3 m. Thus, the groundwater flows from the northern and eastern parts to the central parts and outlet of the basin. Indeed, the farther from the heights, the lower the thickness and the higher the level of the stairway. Therefore, the river is located in the Al-Qaer plain line and plays the role of the drainage of the plain and the outlet of the water of the upper land. In 1382, the water table was the lowest with a depth of 3-16 m. In 2009, however, it was the highest water table with a depth of 3.17-25 m. it was also shown that there was a decline in the amount of the groundwater since 1388 in comparison to 1382 due to harvesting. Conclusion The map obtained from the composition of the layers indicated the importance or weight of each zone in the groundwater potential. The final configuration was divided into three classes with a very suitable, appropriate, and inappropriate potential. Regarding the results and the status of discharge, the eastern and central boundaries of the middle reaches have high potential for the artificial feeding of groundwater. There is also a lower risk for drilling wells. In general, the aquifer of the plain is considered as the limit of humidity and rainfall absorption and water supply required by the middle reaches plain. Physical weathering of the rocks and proper rangeland cover caused plenty of gaps and increased groundwater nutrition in this area. It seems that one of the important reasons for water guidance in the axis of the plain of the navy building and the direction of the slopes of the China's flanks is the drainage of the surface water and the underground water. However, the volume of groundwater in the plain is the only function. The result of the study of water behavior in exploratory and piezoelectric wells has shown that the low drainage density plays the main role in feeding plain in flood plains, coniferous fringes of eastern plains, slopes of 0-2%, and low altitudes. These lands are usually highly influential and because of the fertility and access to surface and underground water resources, the establishment of the demographic and agricultural lands can be seen within them. A significant level of plain lands is flood plain, which plays a very important role in the nutrition of groundwater resources of the plain. According to the maps, the depth of the groundwater level, the main flow of underground water in the plain are from north to south, which indicates that the main river plain in this region plain and evacuates underground water from the area. Sedimentary plain with infiltration infrastructure and young alluvial coverage is the most potential area for water resources in Meiandareh.
