Ali Nasiri khiavi; Raoof Mostafazadeh; Abazar Esmali Ouri; Omid Ghafarzadeh; Mohamad Golshan
Abstract
The hydrological regime of a river is the main influencing factor on the dynamics of river ecosystem and damming operations have a significant impact on river flow discharge. Therefore, the main objective of this research was to investigate the combined effects of changing climate variables and ...
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The hydrological regime of a river is the main influencing factor on the dynamics of river ecosystem and damming operations have a significant impact on river flow discharge. Therefore, the main objective of this research was to investigate the combined effects of changing climate variables and the Yamchi Dam construction on the discharge flow of the Balkhlu-Chai River in Ardebil using IHA Software 7.1 during the pre and after dam construction period (1973-2003) and (2004-2014). Toward this, the trend in the amounts of precipitation, temperature and evapotranspiration variables were evaluated using MAKESENS software. Then, the changes to 33 hydrological parameters and Range of Variability Approach (RVA) were firstly estimated. Subsequently, changes in the parameters of the flow rate in the periods before and after dam construction were investigated in the magnitude, duration, timing, frequency and rate of change categories. According to the results of trend analysis the precipitation had a significant decreasing trend, while, the temperature has been increased during the available time period. Based on the results, about 92% of the minimum flow discharge was attributed to that after the dam construction, while 25% of the maximum discharge belongs to this period, which indicates a decrease in the magnitude of discharge flow due to the dam construction and decreasing trend of rainfall. Also, the number of high flow pulses during the period of before dam construction was 38% higher than the period of after dam construction, while the number of low pulses in the period after dam construction was reduced by 60.7% compared to the period pre-dam construction. The value of Rise Rate index in the after-dam construction period is 0.11, but in the period before the dam construction is 0.3, which indicates a notable decrease in the mentioned indicator. Generally, based on the Magnitude group parameters, it can be concluded that the average amount of river flow during the period after the construction of the dam decreased by 52% compared with the period before the dam construction which lead to considerable environmental issue regarding the river ecosystem and flow condition. It should be noted that the variation in the hydrologic indicators is mainly influenced by the dam construction and also the change of climate variables has also been influential in this regard, and the separation of affecting factors need to be considered in further studies.
Roghayeh Asiabi-Hir; Raoof Mostafazadeh; Majid Raoof; Abazar Esmali-Ouri
Abstract
Availability and supplying adequate water is a fundamental prerequisite for socio-economic development of human societies. The purpose of this study was to evaluate the sustainability of surface water resources. The following criterion including resources (availability, variability), access (access to ...
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Availability and supplying adequate water is a fundamental prerequisite for socio-economic development of human societies. The purpose of this study was to evaluate the sustainability of surface water resources. The following criterion including resources (availability, variability), access (access to health), usage (domestic water use, agricultural water consumption), environment (baseflow, natural vegetation, environmental flow) and socio-economic capacities (literacy rates, the economically active population, employment in non-agricultural sector) were used to assess effective components on surface water sustainability in 21 sub-watersheds of Ardabil Province. The values of different criteria were standardized based on maximum method according to their numerical interval. The comparison of different water related components was provided using multi-dimensional spider-plots in the study area. The lowest and highest values of resource criteria (water per capita and rainfall coefficient of variations) were obtained in Shamsabad (16) and Hir (93) watersheds, respectively. The Nir, Pol-Almas, and Doostbeiglou watersheds having 60, 58, and 54 scores were identified as good condition, considering environment criteria and the other watersheds are critical. The capacity index had the highest and lowest values in Pol-Almas and Polsoltan watershed, respectively. Considering the access criteria, Shamsabad and Ahmad-Kandi watersheds had the highest and lowest scores, respectively. The mean standardized values of resource, usage, access, capacity and environment were 50, 60, 42, 38 and 25, respectively. In conclusion, the results showed that the access and resource criteria had the highest variations, and the environmental criteria were defined as undesirable conditions over the study area. It should be noted that the Central and Eastern parts of the study area had the same condition in terms of their criteria scores.
Khadije Haji; Raoof Mostafazadeh; Abazar Esmali-Ouri; Shahnaz Mirzaei
Abstract
Assessment of temporal and spatial variations of runoff and sediment is needed to sustainable management of watersheds, soil erosion and sediment control, and watershed conservation projects. The amount of discharge and sediment concentration rates were assessed in 15 river gauge stations located in ...
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Assessment of temporal and spatial variations of runoff and sediment is needed to sustainable management of watersheds, soil erosion and sediment control, and watershed conservation projects. The amount of discharge and sediment concentration rates were assessed in 15 river gauge stations located in the West-Azarbaijan Province in a 20-years recorded data using double-mass curve and annual variation analysis (coefficient of variations, annual distribution of regulating coefficient, and concentration rate). The logarithmic rating curve equation was used to sediment estimation according to the nature of discharge and sediment load variations. According to the results, the maximum discharge and sediment amount were observed in the May of spring season that can be related to the high amounts of snow melt and spring precipitation and associated high river flow discharge in the study area. The cumulative double mass curve of the runoff and sediment had a constant slope in the Pole-Bahramlou, Choplojeh, Sarighamish, Peighale, Naghadeh, Dorood, and Chapasabad stations, in which the sediment load is consistent with the runoff amounts. While, the decreasing pattern of sediment load was observed in the Dizaj, Urmia, Dashband, Ghasemlou, and Bayazidabad, which can be related to rainfall decrease and conservation measures (dam construction) and lower sediment amount in the study period. The highest coefficient of variation of runoff and sediment was observed in Pole-Bahramlou (16 and 173 percent), respectively. The highest monthly runoff-sediment uniformity was identified in Chaparabad station, where the lowest concentration rate of runoff and sediment were observed by 0.25 and 0.35 percent respectively; while, the Urmia station identified as a high rate of runoff and sediment concentration rate with 0.58 and 0.84 percent in the study area. It can be concluded that the seasonal variations of runoff and sediment had a consistent manner and some different spatial variations due to climatic, hydrologic and anthropogenic conditions.
Raoof Mostafazadeh; Sonia Mehri
Abstract
Rainfall-runoff relationship is one of the most sophisticated hydrological processes which helps to understand the watershed hydrologic response assessment. The rainfall-runoff relationships of Ardabil Province watersheds were analysed to investigate the spatial variability of rainfall-runoff responses ...
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Rainfall-runoff relationship is one of the most sophisticated hydrological processes which helps to understand the watershed hydrologic response assessment. The rainfall-runoff relationships of Ardabil Province watersheds were analysed to investigate the spatial variability of rainfall-runoff responses using precipitation-runoff polygons technique at a monthly temporal time scale. Therefore, variations of recorded precipitation and runoff data were analysed over a period of 22 years from 1990-2011 in 20 watersheds of the Ardabi Province. According to the results, the maximum runoff coefficient is corresponding to Doostbeighlou Station by the value of 33%. The analysis of precipitation-runoff polygons reveals that the Arbabkandi, Polealmas, Samian and and Doostbeighlou watersheds had the higher amount of runoff coefficient. As well as, the hydrologic response of Shamsabad, Kozetopraghi and Ahmadkandi are similar and homogeneous in term of runoff generation. Based on the relationship between monthly runoff coefficient and the area, the highest correlation coefficient was observed in the March (0.92), and the lowest was assigned to August (0.0089). The larger the area of the polygon and the highest coefficient of variation is corresponding to Doostbeighlou and Samian watersheds. The distribution of the runoff coefficient over the months showed that the Hir and Ahmadkandi watersheds had the highest runoff coefficient in June and August which is related to the delay in runoff production. Based on the results, precipitation-runoff polygon technique is a suitable way to compare the hydrological response and changes in rainfall-runoff relationship of watersheds. It should be noted that the comlexity of rainfall-runoff process causes an overlapping in polygon portions and irregular shapes which caused a difficulty in interpretating of watershed response and needs much more furture researches.
Raoof Mostafazadeh; Mohsen Zabihi; Maryam Adhami
Abstract
Self-similarity characteristic of climate variables provides the spatial and temporal analysis, using fractal dimension. Therefore, the application of fractal geometry in predicting the nature of many natural processes (e.g. rainfall) in several areas is of great importance. The purpose of this study ...
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Self-similarity characteristic of climate variables provides the spatial and temporal analysis, using fractal dimension. Therefore, the application of fractal geometry in predicting the nature of many natural processes (e.g. rainfall) in several areas is of great importance. The purpose of this study is to determine and calculate the fractal dimension of wet and dry periods, interpret and evaluate the spatial characteristics of dry and wet periods over 40 rain gauge stations in Golestan Province. Toward this attempt, the box-counting method has been employed to determine the number of wet-dry months at one to nine months temporal scales and the calculation of fractal dimension. Then, the regression lines are used to estimate the corresponding fractal dimensions over rainy and non-rainy periods. As well as the severity and duration of wet-dry durations were presented over the study area. The results indicated that variations of rainy/non-rainy durations vary in a range of 11 percent. According to the results, the number of consecutive wet-dry months decreased in coarser time scales (months). The analysis of fractal dimension showed that the dry periods have a lower frequency. The fractal dimension values were considered to determine the variations of precipitation regime over studied stations. Also, the intensity of wet durations is higher in central and eastern parts of the study area, while the western part of the Golestan Province had experienced more persistent wet periods.
Ali Abdollahzadeh; Majid Ownegh; Amir Sadoddin; Raoof Mostafazadeh
Abstract
Identification the source areas of surface runoff and flood prone zones and their impact on residential expansion are important. The aim of the present study is to consider the impact of potential runoff coefficient and flood inundation for different recurrence intervals in analyzing residential expansion ...
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Identification the source areas of surface runoff and flood prone zones and their impact on residential expansion are important. The aim of the present study is to consider the impact of potential runoff coefficient and flood inundation for different recurrence intervals in analyzing residential expansion for the current land use pattern as well as suitable land use allocation based on the systemic land use planning of Iran in the Ziarat watershed in Golestan Province. The pre-processed Landsat TM image 2010 was used to determine the land use map of the study area and then a suitability analysis is then carried out to establish the potential residential development area in the framework of Iranian systemic land use planning model. The raster layers of slope, soil type, and land use were prepared and the potential runoff coefficient values were determined using the attributes. Floodplain zonation maps were delineated by integrating HEC-RAS and ArcGIS in different return periods. The results indicate that the residential area covers 3.4% of the study area and 9% of the study area was assigned as 1 and 2 suitability classes, according to land use planning model. On the basis of the potential runoff coefficient map, the average runoff coefficient was 0.51%. Based on the combined flood zone maps and runoff coefficient, the flood prone areas will increase for 25, 50, 100, and 200 year floods for both current and determined residential land uses. The areas of flood-secure regions in current residential land use were 318.47, 317.46, 316.44, and 316.44 ha for different design floods respectively. Increasing the return period from 20-50 to 100-200 years lead to an increase of flood zone extent (3.5 ha).
Seyed Hamidreza Sadeghi; Raoof Mostafazadeh; Amir Sadoddin
Abstract
Assessment of suspended sedimentgraph (SG) and rating loops are important tools for analyzing the behavior of watersheds and successful implementation of watershed management measures in reducing sediment. However, the development and analysis of SGs and rating loops and influencing factors need more ...
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Assessment of suspended sedimentgraph (SG) and rating loops are important tools for analyzing the behavior of watersheds and successful implementation of watershed management measures in reducing sediment. However, the development and analysis of SGs and rating loops and influencing factors need more attention in watershed-scale. Therefore, the present study aimed to conduct the analysis of 13 observed and simulated sedimentgraphs (SGs) during October 2011 and November 2012, in Galaz-Chai Watershed with an area of 103km2 located in West-Azarbaijan Province, Iran. Towards this attempt, the SG of observed events was derived using instantaneous unit sediment graph (IUSG) concept, and the effects of different land uses were investigated. Also, the variation and patterns of the simulated sedimentgraphs (SGs) and rating loops were plotted and interpreted with the respective land use types. Based on the results, an early peak occurred in SGs with respect to the observed hydrograph peak rates and consequently had clock-wise pattern. Increase in falling limb of hydrograph could be attributed to the participation of sediment production from agricultural land in watershed upstream. The model predicted SGs with good accuracy according to the Nash-Sutcliffe criterion (70%). Analysis of results indicated that the type and distribution pattern of different land uses had significant effect on the shape of SGs and sediment rating loops.
Raouf Mostafazadeh; Amir Sadoddin; Abdolreza Bahremand; Vahedbordi Sheikh; Habib Nazarnejad
Volume 2, Issue 2 , July 2010, , Pages 83-93
Abstract
Assessment of flood control projects in the same conditions is essential in order to improve decision making that assist us in watershed management purposes. Focus of this study is on assessing hydrological effects of the Jafar-Abad watershed management project. The study area (109 km2) located in north ...
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Assessment of flood control projects in the same conditions is essential in order to improve decision making that assist us in watershed management purposes. Focus of this study is on assessing hydrological effects of the Jafar-Abad watershed management project. The study area (109 km2) located in north of Iran in the Golestan province. Paired t-tests were performed for Indicators of Hydrologic Alteration (IHA) in Taghi-Abad gauging station, located in the outlet of the catchment, before and after construction of 58 check dams. HEC-HMS model was calibrated using 12 storm events and validated for study area. Calibrated HEC-HMS model was applied to rainfall-runoff modeling in sub-catchments and Level-pool method used for reservoir elements. Design flood hydrographs for 2-100 year return periods were simulated for both before and after check dams construction periods. The results of statistical analysis indicate that existing flood control measures had no significant impact on the hydrologic characteristics measured by IHA in 95% confidence level. The results indicated that constructed structures do not have important effect on IHAs and the amount of these effects was less than 1.5 percent in all cases. Also, by increasing in return period, the effects of structures on peak discharge and flood volume were reduced.
