Gholam hassan jafari; Mina Avaji
Abstract
1-IntroductionEarth's climate is one of the most important structural factors. More natural and human trappings are affected by the weather. The coefficient of variation of less precipitation is reagent stability and steady time distribution (Fatahi, & Rezaei, 2009). The quaternary climatic changes ...
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1-IntroductionEarth's climate is one of the most important structural factors. More natural and human trappings are affected by the weather. The coefficient of variation of less precipitation is reagent stability and steady time distribution (Fatahi, & Rezaei, 2009). The quaternary climatic changes have created different landscapes, such as glacial circus, glaciers, and especially erratic rocks, according to the first topography of Iran that found in high regions of Iran. Geomorphologists' permanent snowline altitude is determined to help the circus of mountain effects. The continuous snow line, altitude above which or latitude beyond which snow does not melt in summer (Ramesht, & Shah Zidi, 2011). The temperature conditions quaternary reconstruct based on a permanent snowline altitude temperature difference compared to today. They also estimate the maximum expansion of tabs by ice moraines, the erratic rocks, valleys of glacial sediments and granulometry, and its height to consider as ice and water equilibrium line altitude. The water and ice equilibrium line is where ice flows entirely replace the water ice flows wholly replacing the water. The quaternary climatic changes, according to particular topography of Iran, have inherited different figures and landforms such as glacial circus, glaciers, and especially wanderer rocks. We cannot analyze by changing one element changes made; a complex mix of elements change been led to changes in the process and enduring numerous landforms. Any anomalies in each component s will cause defects and commotion in the whole system. 2-MethodologyAccording to the geomorphological landform, the remaining lake last is one of the methods of forecasting and estimating their condition. The Climatic factors role has particularly essential in the current situation of the Iranian domestic water hole. We used to examine the relationship between climatic factors and its effect on local lakes, dewatering of the temperature and precipitation data of the 50-year-old Asfazari database in cells 15 x 15 km (Masoudian, 2012). In addition to measurements of temperature and precipitation of central tendency, indexes used of dispersion indexes in statistical processes (Standard deviation and Coefficient of variation). Since the standard deviation is not used to compare the distribution of both characteristic varies with different units, the coefficient of variation (CV) used. Since most time, the Earth's surface has a temperature higher than the surrounding air, in this study were rainfall receiving below two degrees Celsius on the Basin. The coefficient of snow by reducing the temperature was estimated. With put, the factors in its relations appropriate amount of heat and precipitation determined in the Quaternary cold periods. We expect the coefficient of snow and temperature changes and precipitation decrease of 3, 6, and 9°C temperature for sub-study briefly. We cannot continuously study the effect of all elements and factors related to Quaternary climate changes. Still, we are trying to interpret the lake volume fluctuation due to climate change as a system through changes in temperature, precipitation, the coefficient of rain below 2°C, the ratio of variation coefficient of variation of temperature and precipitation.3-Results and DiscussionThresholds obtained show that the basin con ensures the exit of the lake that to be the average temperature of less than 15.78, average annual rainfall more than 215 millimeters, snowy coefficient more than 13 percent, the coefficient of variation of precipitation less than 40 percent and the ratio of difference of temperature more than 7.43. All basins inside Iran changed to a temperature not fit in the Quaternary. Status and evidence there are of lakes dewatering in the Quaternary do not match whit precipitation double and decline of temperature 6-12 degrees compared to the current conditions. So that line equilibrium of water and land could be the effects of the Quaternary terrace lacks by reducing three, nine, and 12-degree temperatures and increased precipitation. Change the line equilibrium of water and land cannot interpret with a temperature and precipitation changes alone, and causality of these changes in the line equilibrium of lakes water and soil must search in changes of precipitation regime and geomorphology of the region4- ConclusionsTo investigate the impact of climate parameters on the dewatering amount of water, we used primarily average of them. Accordingly, they are receiving basins Maharloo (375), Urmia (372), and Meighan (314 mm) maximum and basins Yazd (92), Bafgh (95), and Ardestān (114 mm) minimum of basin precipitation average. The basin has a higher temperature water demand more. If they receive Precipitation equal, drought intensity increases, the average temperature of pond, and their condition are such that allocated the lowest temperature to the basins of Urmia, Meighan, Gavkhoni, and the highest temperature to the lakes Qom and basins Jazmurian, Lute, the Bafgh and Qatruyeh. Basins of Urmia and Meighan have the best conditions. The basins Bafgh and Yazd have the worst conditions dewatering in terms of combining two elements of climate, temperature, and precipitation. These parameters alone will not be able to estimate the dewatering basins' performance reliable be due to the difference in average temperature and precipitation in the basin. Therefore, we used other vectors such as the coefficient of variation of climate (temperature and precipitation) and the coefficient of rain below 2°C. Investigation and compared the ratio of precipitation below 2°C on precipitation full in fourteen basin studies represents that the basins Meighan 21%, Urmia 20.8% and Qom 20.4% allocated to the most extensive and basins Jazmurian 1% and Qatruyeh 0.6% accounted to the lowest percentage of precipitation in below 2°C. To estimate sufficient rainfall in dewatering lakes, we can put number 40 in equation (2) instead of CVp, and we expect threshold precipitation of the basins. Number 40 is a threshold effect coefficient of variation Precipitation in dewatering lakes.Keywords: Quaternary, Climate, line equilibrium of water and land, Interior Lakes of Iran. 5-ReferencesFatahi, E., & Rezaei, T. (2009). Pattern of Daily Climate Circulation on Iran, Journal of Geographical Research, Isfahan University, No. 93: 45-74Masoudian, A. (2012). Iranian Climate, Sharia Toos Publications, Isfahan.Ramesht, M., Shah Zidi, S. (2011). Geomorphology Application in National, Regional, Economic, Tourism Planning, Second Edition, Isfahan University Press.
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 ...
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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.
