Hydrogeomorphology - Articles List

Hydrological Impact Assessment of Land Use Change on Annual Surface Runoff at the Gharasoo Catchment by Using L-THIA Model

Volume 1, Issue 1 , January 2015, , Pages 59-73

Abstract

Catchment land use changing in an area is one of the most important factors in hydrology. As a model, L-THIA was designed to assess the long-term impacts on the hydrology of a catchment for researchers who wanted to determine the relative changes in the runoffs from one land-use condition to another. ... Read More

Analysis of Precipitation Variations of Haraz Watershed Using by Statistical Methods and Spectrum Analysis Technique

Abbasali Dadashi Roudbari; Gholamabbas Fallah Ghalheri; Mokhtar Karami; Mohammed Baaghide

Volume 3, Issue 7 , October 2016, , Pages 59-86

Abstract

Abbasali Dadashi Roudbari[1] Gholamabbas Fallah Ghalhari[2]* Mokhtar Karami[3] Mohammad Baaghide[4] Abstract Identifying the precipitation behavior is the most important principles in environmental planning. Identification of the precipitation behavior in long term period aggrades the way to local and ... Read More Abbasali Dadashi Roudbari[1] Gholamabbas Fallah Ghalhari[2]* Mokhtar Karami[3] Mohammad Baaghide[4] Abstract Identifying the precipitation behavior is the most important principles in environmental planning. Identification of the precipitation behavior in long term period aggrades the way to local and regional planning. This research aim to advance knowledge ahead flood management and process modeling using spectral analysis techniques based on Aphrodite database output over the period 1951 to 2007 in the catchment area located in the southern part of Mazandaran province. The results showed that the coefficient of variation of precipitation over the basin in the warm months of the year was more than cold period. Also, according to the disperse statistics in the catchment area; the largest clusters are created in winter season that represents the relative order of precipitation in the study area. Spectral analysis of precipitation data has revealed significantly sinusoidal cycles 2-3, 5-3, 5-11 and 11 and older. This cycle can be attributed to the impact of macro-scale Atmospheric-ocean. Trend line slope for annual precipitation was obtained 7.67 mm per decade. Exiting of These cycles can be related to the influence of large scale ocean-climate factors in the study area. Of increasing the role of mechanisms wetter, warmer and wetter wet latest in the basin has revealed. The important mechanism that can be considered for increasing trend accompanied by temperature increasing trend is wet-gets-wetter. [1]- M.A. Student in Urban Climatology, Hakim Sabzevari University, IranEmail:dadashiabbasali@gmail.com. [2]- Assistant Professor in Faculty of Geography and Environmental Sciences, Hakim Sabzevari University, Sabzevar, Iran. (Corresponding Autor), [3]- Assistant Professor in Faculty of Geography and Environmental Sciences, Hakim Sabzevari University, Sabzevar, Iran. [4]- Assistant Professor in Faculty of Geography and Environmental Sciences, Hakim Sabzevari University, Sabzevar, Iran.

The Analysis and Comparison of the Suspended Sediment in the Caspian Sea and Central Iran Drainage Basins

Manuchehr Farajzadeh; Ali Asghar Hodaei; Maryam Mollashahi; Neda Rajabi Rostam Abadi

Volume 4, Issue 11 , September 2017, , Pages 59-81

Abstract

Introduction Soil erosion as one of the most important natural hazards of each country usually results in reduced fertility, crop reduction, and desertification, particularly in arid and semi-arid areas. Two-thirds of Iran is located in the arid and semi-arid areas and one of its climatic features is ... Read More Introduction Soil erosion as one of the most important natural hazards of each country usually results in reduced fertility, crop reduction, and desertification, particularly in arid and semi-arid areas. Two-thirds of Iran is located in the arid and semi-arid areas and one of its climatic features is flood. Consequently, soil erosion is one of its environmental problems. Nowadays, since soil is important for the life of products and is directly related to the balance of the ecosystem and the water cycle, its protection and fertility are two important factors that shouldn't be ignored. The purpose of this study was to compare the suspended sediment in two drainage basins of the Caspian Sea, with a humid climate, and central Iran, with an arid climate. Methodology For research surveys, pluviometersdata, sediment and discharge assessment, slope, topography with land use, and lithology were used. Maps were obtained from survey organization, geological survey and mineral exploration, and Natural Rescues of Iran. To this end, land use maps, based on the land use type, were classified into six categories including urban area, forests land, pasture land, agricultural land, swamp land, and arid land, without vegetation cover. In addition, the geological maps, based on the stone resistance and amount of sediment production, were classified into ten categories including the hardest stones, very hard stones, so hard stones, enough hard stones, mediocre stones, enough soft stones, partly soft stones, powder stones, loose stones, and so loose stones. Finally, the data was analyzed using the SPSS software. Results and Discussion The results indicated a high and significant correlation between the rainfall and sediment. There was also a direct and significant correlation between the rainfalls, discharge, and yearly sediment of the field. In addition, a fairly good model was achieved from the rainfall, discharge, and sediments variables. Considering the distribution of the sediment in central Iran, the highest sediment volume was seen in the west of the basin at Shahrokh, Chamriz station. The lowest sediment volume, in contrast, was seen in its north and south. In the Caspian basin, the highest sediment volume was seen in Gharasou and Ran basin at Ghezaghli station. The second highest sediment volume was seen in Gharaghoni station at Sefidrood basin. The lowest sediment volume was seen in Talesh basin and in the southern stations of the Caspian Sea.

Monitoring and Predicting the Wet and Drought Periods in Tabriz Using CLIMGEN Models and SPI

Volume 2, Issue 2 , January 2015, , Pages 61-78

Abstract

The weather forecast data plays an important role in future planning in the natural and human fields. This includes the forecast of droughts and floods, etc., which can reduce potential damages that threaten the preplanned programs. Using CLIMGEN and meteorological data (1961-2009) of Tabriz station, ... Read More

Using Multi Criteria Decision Making and Remote Sensing Techniques in GIS Environment for Flood Susceptible Zones Assessment in Lighvan Chai Catchment

Asadollah Hejazi; Sogra Andariani; Farhad Almaspour; Abolfazl Mokhtari Asl

Volume 2, Issue 3 , January 2017, , Pages 61-80

Abstract

Flood is the main destructive phenomena in Iran which causes human casualties and financial damages every year. The purpose of this research is to define flood susceptible zones in Ligcanchai Catchment. To achieve this end this study provided different information layers such as slope, elevation, ... Read More

The Impact of Land Use and Climate Change on Watershed Runoff Using SWAT Model (Case Study: Garin Watershed)

Mahin Naderi; Alireza Ildoromi; Hamid Nouri; Soheila Aghabeigi Amin; Hossein Zeinivand

Volume 5, Issue 16 , December 2018, , Pages 61-79

Abstract

Abstract Intr4oduction Changing the environmental conditions of a natural ecosystem influences the hydrological responses such as flooding and the extent of erosion and sedimentation of the area. One of the models used to investigate the effect of land use change and climate change on runoff is SWAT ... Read More Abstract Intr4oduction Changing the environmental conditions of a natural ecosystem influences the hydrological responses such as flooding and the extent of erosion and sedimentation of the area. One of the models used to investigate the effect of land use change and climate change on runoff is SWAT model which is a hydrological simulator and a continuous and semi-distributive time-space model with a physical base. Understanding the relationship between land use change and its causative factors and its secondary effects on hydrologic regimes provides essential information for land use planning and sustainable management of natural resources. Investigating the amount and trend of the changes and its effect on the hydrological processes in the basin is a way to predict the state of future changes and provide more effective plans for the sustainable development of the water resources in the basin. The construction of the Garin Dam in the Garin Basin, the risk of filling the sediment reservoir with sediment, reducing its useful life due to seasonal floods, and the effect of basin land use and climate change were the reasons for choosing this area for this research. The purpose of this study was to study the land use and climate change in the studied watershed and determine the effect of these changes on the runoff rate of this watershed in order to better it correctly. Garin Dam is located in the Zagros in the province of Hamedan. It includes the catchment area of the Sarab Gamasiab River to the Garin Reservoir Dam and its area is up to the 22,000 m2. The Garin land basin is mainly mountainous and its range of height ranges from 1833.9 to 3429.2229 m above sea level. Materials and Methods SWAT model input data included climatic and hydrological data (daily precipitation, maximum and minimum temperature, relative humidity, wind speed, dew point, and solar radiation). In this study, the ten year data of Nahavand synoptic station was uased. Topographic maps, digital elevation model (DEM), soil and land use were also used as the input of the model. A digital elevation model (DEM) was extracted using a topographic map of 1: 250,000 of the Garin River basin. SWAT CUP software was used for the calibration and validation of the SWAT model. The calibration data was from the years 2002 to 2007, but the validation data was from 2008 to 2010. In order to determine the degree of the sensitivity of the flow parameters in the SWAT model, SUFI2 software SWAT CUP were used and the sensitivity of the selected 24 parameters were measured. The Elimination of the parameters which had less sensitivity, was based on the calibration process. According to the P-value and T-Stat criteria, the sensitivity of the parameters were determined. The land use maps of 1986, 2000, and 2014 were prepared at the previous stages, and the Markov chain and the CA Markov filter were used to map the land use in 2042. In this research, the outputs of the Hadcm3 model were used to predict Garin's future climate. In addition, the SDSM statistical method was used to fine-scale the output of the general atmospheric circulation models. The SWAT model was also used in the range of calibrated parameters to simulate runoff caused by climate change in Garin basin under two A2 and B2 scenarios. After micro-sampling, the SWAT model was converted and t analyzed for the scenarios. Then, the results of the model implementation with different scenarios and the results of model implementation with the current climate conditions were compared Results and Discussion Regarding the results of the statistical indices, NS index was 0.95. P and R factors were respectively 0.47 and 0.03, and the coefficient of determination (R2) for observed and simulated floodguns was 0.6. Accordingly, the results were confirmed in the calibration phase. The validation phase was conducted to verify the correctness of the selection of the parameters during the calibration period between 2008 and 2010. Given that the Nashatcliff coefficient for Garin's catchment area at the calibration and validation stages were respectively 0.95 and 0.66, , the results were satisfactory and the SWAT model was able to simulate surface runoff in Garin River Basin. In general, due to an increased forest use, an increased permeability and water drainage to the surface and deep water aquifers, and an increased evaporation and transpiration, the amount of runoff has decreased. Regarding the results of temperature, rainfall, and runoff of the next period, it can be seen that in months when rainfall is reduced and the temperature increased, the amount of runoff in the coming period also decreases. The main reasons for this discrepancy can be attributed to the difference in the intensity of land use change as well as the extent of the altered land area, which, given the mountainous nature of the area in the Garin land basin, can be compared to other areas with flat lands with agricultural uses. It is concluded that the effect of climate change in the Garin dam basin is greater than the change in land use due to its mountainous nature. Conclusion The results of the study of the effect of land use change on runoff in the Garin basin indicated that there was a daily and monthly decline in the amount of runoff. The results of the study of the effect of climate change on runoff in the Garin western basin also indicated that there was a daily and monthly decline in the amount of runoff. In both A2 and B2 scenarios, the monthly average temperature, especially in the first and last months of the year, had an increasing trend and rainfall decreased in the spring and winter. It can be attributed to the increased temperature and evaporation, and decreased rainfall. It can also be seen that there was a decline in the average monthly runoff in January, February, April, May and December, with a decreased rainfall, but there was an increase in the average monthly runoff in June, July, August and September, with an increased rainfall. In addition, the effect of land use change on the reduction of runoff in the upcoming period is lower compared to the change effect under A2 and B2 scenarios. It will affect the climate change of the runoff more flatly and the reduction of runoff is more affected by climate change. According to the information obtained from these predictions, it is possible to properly manage the watershed and adopt appropriate management measures in accordance with the conditions of this watershed, prevent unauthorized land use changes, and reduce the damage caused by the phenomenon of the climate change.

The Estimation of Runoff Volume and Maximum Discharge by Using Curve Number (CN) Method (Case Study in Darrehshahr Drainage Basin)

Asdolla Hejazi; Mahdi Mezbani

Volume 2, Issue 5 , January 2017, , Pages 63-81

Abstract

A. Hejaci M. Mezfani Abstract A valid estimation of runoff volume and maximum discharge in the dried and semiarid regions which lack data is important for flood management. One of the estimating methods of runoff volume is related to curve number (CN) of American soil conservatives ... Read More

Identifying Effective Factors on Decline in Groundwater Level Using Wavelet-Entropy Index (Case Study: Silakhor Plain Aquifer

Mehdi Komasi; Soroush Sharghi; Vahid Nourani

Volume 3, Issue 9 , March 2017, , Pages 63-86

Abstract

Time series analysis of hydrological processes plays an important role in accurate recognition of this process. Wavelet-entropy index is a new indicator to assess the fluctuations of time series. In this paper, the effective factor in groundwater level declining in the Silakhor plain is examined using ... Read More

Consequences of Dam Construction on the Ecogeomorphology of Coastal Plains Case Study: Coastal Plains of Sedijch, Gabric and Jagin

Mohammad Akbarian; Siavosh Shayan

Volume 4, Issue 13 , March 2018, , Pages 63-78

Abstract

Extended Abstract Introduction Each part of a shore should be thouroughly considered with its hydrodynamic, lithodynamic, geological, geomorphological, and other peculiarities. In modern conditions, anthropogenic factors should also be included. Only such a multilateral approach can produce results ... Read More Extended Abstract Introduction Each part of a shore should be thouroughly considered with its hydrodynamic, lithodynamic, geological, geomorphological, and other peculiarities. In modern conditions, anthropogenic factors should also be included. Only such a multilateral approach can produce results which reflect the actual situation as closely as possible. Arid lands and coastal zones are the most favourable areas for wind processes. The analysis of the forms and coastal conditions provides a valuable key for coastal management. A beach can be composed of a wide variety of materials of many sizes and shapes. The river load is one of the hydrological elements that affects the beach. Particle size windows (PSWs) are interpreted as reflecting different modes of sediment transport and deposition. In a related research on western Makoran coastal plain, Shayan et.al (2014) found that the distribution of the internal sand masses on the plain was affected by the extent of the old beds and floodplain that were exposed to the prevailing wind rather than wind function. The aim of this study was to identify the effect of river’s flows on sedimentological characteristics of the shoreline in the western part of Mokran coastal plain, Iran. The major process that formed coastal plains were fluvial processes. In semi arid areas, the geomorphological impacts of dams are very major. The purpose here was to identify the consequences of dam construction on vegetation and aeolian geomorphology with an emphasis on the ecogeomorphology of the western part of Makran coastal plain. The study area is located at 25o31’-25o50’N, 57o52’-59o02’E, in the western part of the coastal plain of Makoran, the southern part of Iran, the northern part of the Oman Sea, and the eastern part of Strait of Hormoz. In general, the region under research could be assumed a dry land with very low rain, windy, sand storm, torrent shower, thunder-storm, higher humidity, and hazy down (Akbarian et al., 2006). Geologically, it is affected by Mokran (Makoran) region's general construction and it is mainly composed of shaile, marl, and sandstone layers. Methodology Research data included spatial distributions of coastal lanforms, rivers' hydrodinamic data, data of surface morphometric specialy slope, and type of vegetation. Maps of geology and topography, satellite imagery, aerial photos, GPS and computer softwares such as Freehand and ArcGIS were used. Morphodynamic changes of the rivers were investigated by using hydrometric station's data, comparing the satelite images and areal photos, and gathering the results of other studies. The Coastal plain's topographical and geological charecteristics, the distribution map of landfoms, the vegetatin cover, and coastal dunes were also studied. Then, based on the geomorphological analysis and information from field works, the possible ecogeomorphological consequences of dam construction were studied. Discussion The exploitation of coastal rivers have had an enormously negative impact on coastal zone and a deleterious effect on the natural dynamics of river loads. The basins leading to the Coastal Plains of Sedijch, Gabric, and Jagin have high sedimentation discharge. According to the results, the hydrodynamic effects of these rivers have a special effect on the formation of plain landforms. The sources of the sedimentation of sand masses and the establishment of forest cover on adjacent coastal plain are affected by river’s hydrodynamic. Once dams constructions on these rivers are complete, sediment load virtually comes to an end. In the near future, major changes can be expected at the mouth of the rivers and along the coastal zones of this region. However, dams could cause serious environmental damage in the downstream of these rivers. They may increase the severity of wind erosion, the performance of waves in sediment drift along the coastline. They will also have negative effect on the amount of forest cover on upland of these coastal plains and especially mangrove wetlands. These results are consistent with the following researchers. According to Nanson and Croke (1992), as a result of environmental modifications on rivers, flood plains affected by major rivers evolve over time. In a study of hydrology, geomorphology and vegetation in the southeastern coastal rivers of the United States, Hop (2000) concluded that the vegetation diversity of the coastal plain has adapted to long flood periods and anaerobic conditions. Based on Berkun (2014), the natural course of fluvial alluvium transport is almost completely altered because of planned and constructed dams and coastal protection measures. Decreasing volume of sediment carried to the sea cause intensification of the shore erosion (Berkun, 2012). Sulimanirad et al. (2011) stated that the habitat of the protected area of Gabrij (the whole range of Gabriel coastal wetlands, Jengin, and Sourgelm) is threatened and possibly destroyed due to the construction of a dam on the Jegin River, camel grazing and the destruction of mangroves. Conclusion The present study showed that water and sediment discharge of rivers and their hydrodynamic has a special role in the formation of coastal landforms, specially on aeolian landforms, and the stablishment of mangrove on lagoon and Persian Gulf-Oman(Sahara-Sendi) forest habitat on upland deltas. Lake of fluvial processes in the long period will probably have destructive consequences on the ecology and geomorphology of this coastal region.

The Investigation of the Groundwater Vulnerability to Pollution Using DRASTIC and GODS Models (A Case Study: Rafsanjan Plain)

Majid Ramezani Sarbandi; Reza Ghazavi; Siamak Dokhani; Seyyed Mostafa Mortazavi

Volume 4, Issue 10 , June 2017, , Pages 65-80

Abstract

Groundwater is one of the most important natural resources in the world. Currently, the considerable part of Iran's water consumption, minly its drinking water, is provided from underground water sources. The emission of the surface contaminants to groundwater resources, especially in the arid and semi-arid ... Read More

Zoning Suitable Areas for Artificial Recharge Aquifers of Sabzab and Gotvand Plains Using Fuzzy Model and Matching of the Alluvial Fan

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 ... Read More 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.

Evaluation of the Efficiency of Time Series and Fuzzy Models in Monthly Discharge Modeling (Case Study: Kohsukhteh Watershed)

Sodabeh Behyan Motlagh; Afshin Honarbakhsh; Khodayar Abdolahi; Mehdi Pajouhesh

Volume 6, Issue 21 , March 2020, , Pages 65-86

Abstract

1-IntroductionStreamflow modeling is an important attitude generally considered for planning and management of water resources as well as watershed management practices. Thus it is highlighted as one of the fundamental issues in applied hydrology. It is also one of the methods used for modelling streamflow ... Read More 1-IntroductionStreamflow modeling is an important attitude generally considered for planning and management of water resources as well as watershed management practices. Thus it is highlighted as one of the fundamental issues in applied hydrology. It is also one of the methods used for modelling streamflow processing methods, which is considered as one of the common black–box methods that correlates input and output data. Regression techniques and time series models have been derived from data processing methods.Since 1962, use have been made of hydrologic as well as stochastic methodsfor flow discharge modeling asAutoregression (AR), Moving Average (MA), Autoregressive Moving Average (ARMA) and Autoregressive Integrated Moving Average (ARIMA) statistical models were introduced.Application of both fuzzy and time series models in discharge modeling of conducted studies, have shown the appropriate results of discharge estimation. The purpose of this study wasto evaluate the performance of two time series models (ARIMA) and fuzzy least squares regression with symmetric triangular membership function in streamflow modeling. Consideringthe background of the research, the least squares fuzzy regression method had not been used and no comparisons have been made between this model and time series model. Since both models arefrom black-boxed family, the present study have used both models and their efficacy have been evaluated.2-MethodologyThis study aimed atsimulating the average monthly discharge of KoheSokhteh Watershed. This region has been located inShahrekord, Boroujen and Kiar in Chaharmahal and Bakhtiari province.The monthly data and an average of 25 yearshave been used. The ARIMA model investigates the modelling of auto-correlated and random components shown as .It has to be noted that the values cannot be negative.-Identification of the type and rank of model for investigating timeseries modelsThe autocorrelation function (ACF) and the partial autocorrelation function (PACF) were used in order to determine the type and rank of the time series model. Having diagnosed model`s ranks, a modal of model`s figure is identified and model`s parameters are appointed through obtained correlational function. ACF charts are obtained with k delay. The other way for expressing the time dependency of the time series data is to define the PACF function. If beconsidered as partial autocorrelation function with k delay,….-Parameters` estimation and model adequacyAfter choosing an appropriate model along with its order, the next step is to estimate the parameters of the selected model. We should calculate the remaining values that follow the normal distribution with a zero mean using multi-year data for simulated discharge values. Before starting simulation, data is transformed to a normal data set.-Calculating the relationship between fuzzy least squares` regression model In this section, the dependent variable of discharge is considered as a fuzzy dataset and observations related to independent variables (precipitation, evaporation, squer root, lag time) are consideredas non-fuzzy variables. Based on this type of data and taking the 20 percent as theallowance error for the measured data, a model with fuzzy coefficients is fitted to the data.-Data used in the modelThe data was provided based onobserved data of observation matrices as well as matrix A. The matrices s and y, and also the matrices a and σ, were calculated. If Rank (x)=n+1, then the matrix A would bea definite positive. If A wasa definite positive, it would havea reverse A-1, andthe relation between σ and α would haveunique answers.-Description of the performance of least squares fuzzy regression model in watershedsWith regards to the matrix X, the observation matrix (matrix X) was calculated for watersheds. Then the calculation proceeds using the matrix of observations and matrix A. Matrix A was calculated for three of the watersheds. After calculating the matrix A, the y vector (discharge observation values) was calculated for watersheds. Then the s vector wascalculated for each watershed. Finally, the optimal fitted model applied to the data as well as α and σ matrices were obtained.3-ResultsIn order to develop time series models, it was identified in the initial analysis that once applying differentials forconverting an unstable time series to a static time series was sufficient. Nextstep wasidentifying the order of the model. ACF as well asPACF graphshave been utilized. ACF suggested MA and PACF suggested AR. Subsequently a combination of MA and AR was proposed for modeling this series. The parameters of the selected model were calculated using the MINITAB software based on the information extracted from PACF and ACF. Standard errors of the parameters for the selected model were relatively small, indicatingthe applicability of the parameters in modeling.-Fuzzy least squares regression-Estimated dischargeThe values of estimated discharge of watersheds were calculated using fuzzy least squares regression. The results of the estimated discharge have been shown in Table 2.4-Discussion and conclusionTo investigate the efficiency of the ARIMA time series model and fuzzy model at monthly forecasting scale, ARIMA model as well as fuzzy least squares regression models were utilized. Both models properly predictedmonthly discharge. The predicted discharge values using ARIMA model were lower than the observed discharge values. In the fuzzy least-squares regression model, peak discharge was well modelled but discharge with low values had further differences with the observations.During the calibration phase, the fuzzy least squares regression model showed a Nash-Sutcliff coefficient of 88% and ARIMA (211)(111) model had a Nash-Sutcliff coefficient of 84%. The least squares fuzzy regression model with low difference showed a superior to ARIMA model. The fuzzy least squares regression model`s superiority showed less effect of seasonal changes in predicting discharge, which was in contrast to Moayeni et al. (18) research.

Priority of Relative Proportion in Erosion and Sediment Yield by Using Mixing Models and Genetic Algorithm (Case Study: Tange Bostanak Watershed

Ahmad Nohegar; Mohamad Kazemi; S.Javad Ahmadi

Volume 4, Issue 12 , December 2017, , Pages 67-87

Abstract

Extent Abstract Introduction Considering the impact of accelerated rates of sediment yield and soil erosion on catchments, which results from land clearance and poor land management (Palazón et al., 2015) including soil degradation, environmental pollution, and sedimentation in dam reservoirs, ... Read More Extent Abstract Introduction Considering the impact of accelerated rates of sediment yield and soil erosion on catchments, which results from land clearance and poor land management (Palazón et al., 2015) including soil degradation, environmental pollution, and sedimentation in dam reservoirs, the reduction of the sedimentation is required to implement appropriate methods of sediment control and soil conservation in the critical areas of sediment resources in the catchment (Patrick et al, 2015). In addition, the recognition and identification of the relative importance of the sediment resources and their contribution (Chen et al., 2016) to sedimentation are necessary for identifying appropriate methods and proper implementation of soil conservation programs. The sediment finger printing is a direct approach to identify the relative contribution of each source and provides a direct approach for quantifying sources of sediment. A fingerprint of sediment sources is obtained using radionuclides, tracer metals, or other sediment properties, which enables the determination of the relative source contributions (Motha et al., 2004). Including the erosion and sediment, the important thing is to choose a model or method to estimate the actual loss or erosion of soil and the contribution of each source to its value. There are few studies estimating the level of GOF and ME on sediment fingerprinting approach to determine the relative contribution of each of the resources. GOF and ME allow making better informed decisions on sediment management (Minella et al., 2008) and can reliably determine mixing the contribution of each sediment source in mixing models (Collins et al., 2010). Methodology The study area, Tange Bostank catchment, covers an area of 81.73 km2 and is located at about 80 km far from the Northwest of Shiraz, at the geographical location of 52° 03' 43'' to 52° 13' 36'' in the East and 30° 16' 33'' to 30° 25' 18'' in the North. Geological formations maps were provided as Razak, Kashkan, Bakhtiari, Quaternary, PabdehGurpi, and Asmari formations using SFF method. Land use maps were also provided as rangelands, forests, gardens, and irrigations using ML method with Landsat satellite image 8 of OLI sensor. Discriminating sediment sources to confirm the discrimination of the potential sediment sources was done in two steps. The first step was based on the use of the Kruskal–Wallis H-test to discriminate the potential sources by the fingerprint properties. In the second step, stepwise multivariate discriminant function analysis (DFA) was used to identify the optimum combination of the tracers passing the Kruskal–Wallis H-test and to maximize discriminating between the potential sources. The multivariate mixing model (Walling, 2005) involves minimizing the sum of the squares of the residuals between predicted tracer values for each source in sediment samples and the observed values. The sediment source apportionment involved a comparison of the results obtained using several multivariate mixing models. Using an optimization source proportion minimizes the errors in mixing models. We minimized the sum of the squares of the relative errors (R) in the objective functions( Eq.s 1-5). Eq.1: Eq. 2: Eq. 3: Eq. 4: Eq. 5: where: ci = concentration of fingerprint property (i) in sediment samples; Sij = concentration of fingerprint property (i) in source category (j); X j = percentage contribution from source category (j); Z j = particle size correction factor for source category (j); Oj = organic matter content correction factor for source category (j); Wi = tracer discriminatory weighting or tracer specific weighting; SVji = weighting representing the within-source variability of fingerprint property (i) in source category (j); VARij = variance of the measured values of tracer in source area j; mj = the total number of samples for an individual source; n = number of fingerprint properties; m = number of sediment source categories. Genetic Algorithm optimization (GA) was employed to find the optimal source sediments contribution. In addition, goodness of fit (GOF) equation and Mean Error (ME) were used to determine the results of each of the mixing models (Eq.6 and Eq.7) Eq.6: Discussion Soil erosion and sediment yield are the most destructive phenomena that cause a lot of damages in different regions. However, in order to combat them, it is needed to be aware of the sediment sources location in the region. Sediment fingerprinting technique, based on geochemical tracers, organic and isotopic ratios, and various mixing models, is used in the recognition of the contribution of the different sediment sources in an area. In this study, the optimum combination of organic and rare tracers was used to separate the different sources. In addition, to determine the contribution of this erosion and sediment yield resource, Collins, Collins modified, Motha, Landwehr and Slattery models associated with genetic algorithm optimization were used. The results of the discriminant analysis showed Compounds of C, Cu Si, and Ti as tracers for land uses and four tracers (Nd143/144, Cu, Si,Ti) to discriminate between geology formation’s source categories. To determine the best model, GOF and ME indexes were used. Tables1-4 render the results of applying the ME and GOF indices to select the best models in formation and land use units. The M Collins and Collins mixing models with GOF and ME indices of 99.95%, 99.996% and 99.16%, 99.977% were respectively selected as the best models in land use and formation units. According to ME and GOF results, the calculated relative contributions of the range lands and the Asmari formation with 65% and 56.5% were the highest. Moreover, sedimentation rates of sub basins number 6 and 5 with 59.11% and 58.7% were very important in the management of the soil conservation (the highest proportion in sediment and erosion basins) and sub basins number 31 with 7.54% were not important in the management of the soil conservation (minimal role in Sediment yield of Tange Bostanak watershed). Conclusion Soil erosion and sediment yield are the most destructive phenomena that cause a lot of damages in different regions. However, in order to combat them, it is needed to be aware of the sediment sources location in the region. Sediment fingerprinting technique, based on geochemical tracers, organic and isotopic ratios, and various mixing models, is used in the recognition of the contribution of the different sediment sources in an area. In this study, the optimum combination of organic and rare tracers was used to separate the different sources. In addition, to determine the contribution of this erosion and sediment yield resource, Collins, Collins modified, Motha, Landwehr and Slattery models associated with genetic algorithm optimization were used. The results of the discriminant analysis showed Compounds of C, Cu Si, and Ti as tracers for land uses and four tracers (Nd143/144, Cu, Si,Ti) to discriminate between geology formation’s source categories. The M Collins and Collins mixing models with GOF and ME indices of 99.95%, 99.996% and 99.16%, 99.977% were respectively selected as the best models in land use and formation units. According to ME and GOF results, the calculated relative contributions of the range lands and the Asmari formation with 65% and 56.5% were the highest. Moreover, sedimentation rates of sub basins number 6 and 5 with 59.11% and 58.7% were very important in the management of the soil conservation (the highest proportion in sediment and erosion basins) and sub basins number 31 with 7.54% were not important in the management of the soil conservation (minimal role in Sediment yield of Tange Bostanak watershed).

Investigation and Estimation on the Rate of Aras River Displacement in its Floodplain

Maryam Bayati Khatibi; Fariba Karami

Volume 5, Issue 14 , June 2018, , Pages 67-89

Abstract

Introdution Alluvial floodplains, and in particular those associated with the world's largest rivers, have a complex relief that is produced by recurring erosional, and depositional events.The magnitude, heterogeneity, spatial distribution, and connectivity of this relief controls river floodwater ... Read More Introdution Alluvial floodplains, and in particular those associated with the world's largest rivers, have a complex relief that is produced by recurring erosional, and depositional events.The magnitude, heterogeneity, spatial distribution, and connectivity of this relief controls river floodwater routing and storage, sediment dispersal, and biogeochemical cyclingChannel Lateral movement and course changes are main causes for floodplain extend ,bank erosion and soil loss due to cut bank .Aras river that located in NW of Iran(from 45°E to 48°E), have many curvatures on course and due to this reason Aras is made high rate movement yearly .Aras is a boarder river and for this reason is very important that direction is determined . Methodology In this article for determining the rate of lateral movement is used landsats 5,2 (Mss) landsat5™landsat 7(ETM+) and landsats(OLI) with 30 and 15 resoulation in 1985 to 2015 epoch. In this study is used Rm, R and MI for rate and degree movement and rate of river course curvature . In order to determining of power flow against instability of mater in this article is used MI idex: MI=S√Q/D50 And for determining of rate of displacement of channel, is used of Rm index: Rm=(A/L)/Y Discusses Investigation on the curvature radial Aras channel show that average rate of radial is 509.62 m. In other site this rate is 515.71 m. The study also show that changes in Aras river course is vary .When wide is high ,channel migration is excess .In recent time this changes is high ,but rate of migration in Iran site and other site is decrease to compare of past time .The average of channel migration to Iran site is 27,21m in 2010 and other site rate is 28,32 m. Results Sum all area that located at other site due to displacement are 1410255 m3 (1985-2015).Area in site of Iran is 2230869 m3 (1985-2015).That is to say ,difference is 820614 m3.This has meaning that our land and soil is placed other site due to channel movement .Yearly average displacement of channel Aras river is 475 m at Iran site and 353 m at other site .So ,displacement at two site is vary .Over the past three decades, the fluvial dynamics of meander bends, including processes related to outer bank erosion, have been the focus of numerous scientific investigations. Despite this effort,a comprehensive understanding of the hydraulic processes of outer bank erosion—especially the role of flow turbulence—remains elusive.Because natural river flows are fully turbulent, the erosive stresses acting on the banks of meandering rivers should be related to turbulent stresses. Current models of outer bank erosion, however, rely on simple parameterization of the flow via excess velocity, excess shear stress at the bank toe, or excess flow depth . Aras River is very dynamic .This river make curvature in its curse and cut bank .When river make meander in flow curse ,cut power of flow is increase .This high power is energy for bank cut and movement .Soil lost is other result for cut bank .This story is happened in northern border of Iran .

Estimation of Actual Evapotranspiration by Mountain SEBAL Algorithm Based on Pea Plants (Case Study: Semi-Northern Half of Ardabil Province)

Mehdi Asadi; Khalil Valizadeh Kamran; Mohammad Baaghideh; Hamed Adab

Volume 7, Issue 22 , June 2020, , Pages 67-85

https://doi.org/10.22034/hyd.2020.14583

Abstract

Monitoring evapotranspiration has important implications for global climate modeling. Therefore, the evapotranspiration rate of different land uses in the northern half of Ardebil province based on object-based classification with Kappa coefficient of 0.945 and overall accuracy of 0.956, using Landsat ... Read More

Application of M5 Tree Model in Forecasting Drought (Case Study, Maragheh, Iran)

Mohammadtaghi Sattari; Rasoul Mirabbai Najafabadi; Masood Alimohammadi

Volume 3, Issue 8 , December 2016, , Pages 73-92

Abstract

Received: 2015.08.16 Accepted: 2016.11.18 Mohammadtaghi Sattari[1]* Rasoul Mirabbasi Najafabadi[2] Masood Alimohammadi[3] Abstract Accurate prediction of droughts in arid and semi-arid countries, like Iran, have important role in water resources management and designing appropriate plans for coping with ... Read More

Determination of Effective Factors in Locating Runoff-prone Areas and Rainwater Extraction of Kermanshah Siahkhor Watershed

Fariba Darabi; Alireza Ildoromi

Volume 8, Issue 28 , December 2021, , Pages 1-18

https://doi.org/10.22034/hyd.2021.10524

Abstract

Rainwater harvesting is a way to develop the utilization of water resources in arid and semi arid regions with the aim of increasing the quantity and quality of water resources. The purpose of this study was to determine the factors influencing the location of areas susceptible to the construction of ... Read More

Investigation of Groundwater Nitrate Pollution with Different Interpolation Methods (Case Study: East Azarbayjan, Bilverdy Plain)

Volume 1, Issue 1 , January 2015, , Pages 75-92

Abstract

Abstract Nowadays application of geostatistical interpolation methods is very important in estimating the spatial distributions in all aspects of water science. Likewise, acquiring sound knowledge on the quality and conditions of the groundwater for different usages is vital. However, the measurement ... Read More

The Groudwater Potential Assessment by the Use of AHP and Fuzzy Technuques (Case Study of Northern Basins of Ilam Province)

Sorayya Abbasi; Masoud Heydari

Volume 3, Issue 6 , January 2017, , Pages 75-93

Abstract

Sorayya Abbasi[1] Masoud Heydari[2] Abstract One of the important issues in water resources management is the identification of ground water behavior. The aim of this paper is the estimation and comparison of two methods for potential ground water, sites by the use of Analytical Hierarchy Process (AHP) ... Read More

The Determination of the Influential Parameters in Hydrochemistry of Hard Rocks and Karstic Groundwater in the West of Urmia, Iran

Hamed Jafarian; Abdorreza Vaezihir; Hossein Pirkharrati

Volume 5, Issue 15 , October 2018, , Pages 75-94

Abstract

Abstract Introduction The investigation into water resources of hard rocks and limestone, is very important because of their quality and role in the supply of the portable water. More than 10 percent of Iran is covered with hard rocks formations which increases up to 25% in the northwest of Iran. Because ... Read More Abstract Introduction The investigation into water resources of hard rocks and limestone, is very important because of their quality and role in the supply of the portable water. More than 10 percent of Iran is covered with hard rocks formations which increases up to 25% in the northwest of Iran. Because of the high quality of hard rock and karstic aquifers and their suitable location for supplying the drinking water of rural areas, the exploration and exploitation of groundwater from these formations are of interest. In quantitative terms, while the frequency of springs in hard rocks is normally more than that of karstic aquifers, the discharge of karstic springs is normally higher. The hydrochemistry of groundwater in hard rocks and limestone is influenced by aquifer body material, groundwater flow velocity, and residential time of water in aquifer. Methodology The study area was located in the west of Urmia City, northwest of Iran as a part of Lake Urmia watershed. The geological units is mainly carbonate rocks (limestone and dolomite). In order to investigate the quality of groundwater resources, 15 samples of springs were collected and analyzed for the major ions (HCO3, CL, SO4, Mg, Ca, Na, K). Other parameters such as TDS, PH and EC were also measured. Various diagrams and techniques like Durov and Gibbs diagrams, saturation index, and ion ratios were employed to determine the water type and faces and the source of ions. Also some diagrams were used to check water quality for agricultural and drinking usages. Results and Discussion Pie diagrams of SO4, Na, and EC showed that the basin area located in young alluviums bearing gypsum caused an increase in SO4 and EC. Marls of Miocene formation in the area also had increased the concentration of Na in some water samples Based on the samples position in the Piper, Durov, and Gibbs diagrams, most types of groundwater was bicarbonate and calcic types. The main factors which controled the groundwater chemistry were processes such as ion exchange (due to the presence of clay minerals), weathering, and dissolution of limestone and dolomite formations. It was also found that the watersheds of the large number of springs were located in Permian limestone and detrital Miocene units. Wilcox diagram showed that most of the samples were in the class C2-S1, which indicated their low salinity and their appropriateness for agriculture. Schoeller diagram also showed that the groundwater region had good and acceptable quality for drinking. Saturation index survey showed a highest value of unsaturity related to dolomites for the samples which is influenced by Silvana dolomitic formation. Under saturity of samples related to gypsum, halite, and anhydrate was expected because of the absence of saline gypsiferous formations in the area. Conclusion The results of this research showed that the groundwater of the study area has a water with calcic and bicarbonate types with a high hydrochemical quality, which is appropriate for agriculture and drinking uses. It was also found that lithology has a major role in the hydrochemistry and quality of the groundwater. Weathering and solution of Routeh and Tertiary limestone karstic formations, and Silvana dolomitic formation have more impact on the groundwater quality of the study area. However, alluvial gypsiferous and Miocene formations with marl beds have a little impact on the quality of groundwater in the north, center and east of the area.

Evaluating the Quality of Mehraban Plain Groundwater Resources Using GQI and FGQI Methods

Volume 2, Issue 2 , January 2015, , Pages 79-98

Abstract

Mehraban Plain is located in the eastern part of the East Azarbaijan province. In this plain groundwater resources are the main source of water supply for drinking. In this area the bedrock of the aquifer and its surrounding high lands are mainly formed by Neogene sediments including gypsy and ... Read More

The Assessment of Salinity and Arsenic as the Destructive Factors Affecting on Surface and Ground Water Quality of Sahand Dam water Basin

Atallah Nadiri; Fariba Sadeghi Aghdam; Asghar Aghari Moghaddam; Keivan Naderi

Volume 2, Issue 4 , January 2017, , Pages 79-99

Abstract

Ata Allah Nadiri[1]* Asghar Asgharai Moghaddam[2] Fariba Sadeghi Aghdam[3] Keivan Naderi[4] Abstract Water demand management and water supply for different usages associated with identification, control and reduction of water pollution for improving water quality and environmental indices are the main ... Read More Ata Allah Nadiri[1]* Asghar Asgharai Moghaddam[2] Fariba Sadeghi Aghdam[3] Keivan Naderi[4] Abstract Water demand management and water supply for different usages associated with identification, control and reduction of water pollution for improving water quality and environmental indices are the main purposes of water resources management in the country. Sahand Dam reservoir is the main source of water to supply drinking, industrial and agricultural demands. Therefore, the illness reported from residents due to high concentration of arsenic (200 times more than the permissible limit of drinking water) in drinking water, show the importance of the study of water quality in the area. To determine the quality of water resources for different consumptions, 50 water samples were collected from the water resources of the area and analysed in the hydrological lab of the Geolology Department of Tabriz University. In addition, data collected by the researchers sector of East Azerbaijan Regional Water Authority for studying the Sahand Dam also were used. In this research, Factor analyzing and time series variations methods for determing factor effecting on hydrogeochemistry of the area were used. Quality monitoring and hydrochemical factors affecting water resources of Sahand Dam identify two main factors affecting hydrochemistry of groundwater of the study area which are arsenic and salinity anomalies. In this regard the main anomalies, origins and areas affected by these anomalies were recognized and the distribution maps of these factors in the study area were prepared. [1]- Ph.D of Hydrogeology, Assistant Professor, Faculty of Natural Science, University of Tabriz (Corresponding author), Email:nadiri@tabrizu.ac.ir. [2]- Ph.D of Hydrogeology, Professor, Faculty of Natural Science, University of Tabriz. [3]- M.Sc of Hydrogeology, Department of natural science, University of Tabriz. [4]- M.Sc of Hydrogeology, Department of natural science, University of Tabriz.

The Study of the Periods of Drought and its Impact on Groundwater Resources of the Gorgan Roud River Basin

Narjes Bay; Shima Niko; Vahid Feizi; Haydeh Ara

Volume 4, Issue 13 , March 2018, , Pages 79-97

Abstract

Abstract Introduction Drought, with its gradual, tranquil, and crawling occurrence, is one of the most important natural disasters that affects various aspects of human life. This phenomenon, as a disastrous climatic phenomenon, directly affects communities through changes in their access to water ... Read More Abstract Introduction Drought, with its gradual, tranquil, and crawling occurrence, is one of the most important natural disasters that affects various aspects of human life. This phenomenon, as a disastrous climatic phenomenon, directly affects communities through changes in their access to water resources. One of the most important effects of drought on water resources is the reduction and drop in groundwater aquifers and the decrease in river flow rates. The hydrological drought, with the effects of periods of atmospheric drops, affects the sources of groundwater or surface water supplies such as river flows, reservoirs, lakes, and groundwater. Therefore, the effect of the rainfall shortage on the components of the hydrological system such as soil moisture, river flow, surface of reservoirs, and groundwater is seen after a long time. Climatological drought with a time lag in one place leads to a hydrological drought which, consequently, leads to water stress. Determining the starting and ending dates of droughts, their severity, continuity, spatial distribution, assessment, and quantification is one of the most important issues in the study area. Accordingly, the main objective of this research was to determine the extent of the continuity of meteorological and hydrological droughts and the relationship between them. Methodology The Gorganroud River watershed forms 48% of Golestan Province with an area of 11393.1 km2. It is located in the geographical range of '36 ° 36 'to 37 ° 37' the northern latitude and '00 ° 54 'to '29 ° 56 the eastern altitude. It is located in the national scale of the Gorgan River basin in the north of the country. From the south east to the eastern Alborz, from the east to mount Aladagh and mount Glydiyah, from the north to the Atrak basin, and from the west to the Caspian Sea and the Gharasso basin. The Gorganroud River has 17 main branches that are connected in different parts and, ultimately, flood the Caspian Sea. The basin is used as a forest in the south and east, but in the north and west, alluvial plains are exploited in agriculture and pasture. In order to study droughts, the standardized precipitation index (SPI) and standardized water-level index (SWI) were used. The data used in this study was extracted from 16 meteorological stations and 31 piezometric wells, with a common statistical period of 30 years (1362-1392). To analyze the droughts' trend, seven scales of 1, 3, 6, 12, 24, and 48 were used in a monthly and annual scales. In this study, to reconstruct the statistical errors and homogenize the data, acorrelation and normal ratio methods were used. Then, the SPI and SWI indices and the quantitative analysis of droughts of basin were used to evaluate the trend of rainfall and underground water in different spatial and temporal scales. Result According to the calculations and checking the map of the annual extent of meteorological drought, the western and eastern regions of the basin were affected by drought more than other regions. In addition, according to the map of the annual extent of the groundwater droughts, the southwestern, western, and northern parts were affected by drought more than other regions. Considering the duration of the meteorological drought, the northeastern, western, and southwestern parts had longer durations than other regions. Considering the duration of the groundwater drought, the northern, southwestern, and central parts of the basin had the longest duration.

The Boundary of the Quaternary Glacial Morphogenes System in the Water Basins of the Northwest of Iran

Gholam hassan jafari; Nasrin Hazrati

Volume 6, Issue 18 , June 2019, , Pages 79-96

Abstract

Introduction The climate change that has started since the Quaternary period continues to shape the current morphology of the Earth. During the Quaternary period, glacial and interglacial periods have been continuously occurring and have undeniable geomorphologic evidence. Using this evidence, it is ... Read More Introduction The climate change that has started since the Quaternary period continues to shape the current morphology of the Earth. During the Quaternary period, glacial and interglacial periods have been continuously occurring and have undeniable geomorphologic evidence. Using this evidence, it is possible to determine the ELA and the extent of glacial expansion and the study of climate change. This is because of the fact that exogenous Earth-changing processes have not been able to completely eliminate the remaining effects of quaternary glacial erosion (Yamani & Zamani, 2007: 100). The Northwestern unit, which is the intersection of the northern and southwestern mountain ranges of Iran, is a mountainous region. There is an extensive evidence of Quaternary glacial activity remained in this unit. In this regard, this article seeks to estimate the Quaternary ELA considering the glacial effects of the region. Talrghani (2012) has introduced the Northwestern unit as a mountainous region of Iran, as the north and southwest mountain ranges of Iran meet with different structures in the area; in addition, since the northwest is the intersection and the density of the three plateaus, it has led to its complexity and disorder of its terrains. Methodology Among the basic issues in glacial studies are the ELA and the water and ice equilibrium line .Using topographic maps with the scale of 1: 50000 and the reflection of the glacial evidence on maps, more than 4000 cirques, dispersed among the basins of Aras, Sefidrud and Lake Urmia, were identified. The overall direction of the identified cirques was determined according to the continuity of the terrains in a way that the main ridge of each basin determined the direction of the formation of the cirque. Using the geological map with the scale of 1: 100000, the lithological conditions of the cirques location were investigated. The data of those cirques located in sediments that had not undergone diagenesis such as conglomerate and were loose (such as marl, clay, and evaporite sediments) were extracted. Considering the mountainous nature of this region, glacial cirques were identified in the western, eastern and central parts of the unit. The ELA was estimated by Wright, Cirque-floor altitude, Terminus-to-Head Altitude Ratio (of Wright and Porter), and Altitude Ratios' methods.ResultsIn this geomorphic unit, glacial cirques can be formed from a height of 1800 m above the surface. The analysis of the ELA estimated by cirque-floor altitude method indicated that it was more consistent than the other methods due to the reflection of the direct effects on ELA. The ELA between 2453 m (Aras basin) to 2685 m (Sefidrud basin) was estimated (with 232 m height difference). This difference indicated a decrease in the ELA from the south to the north. The average elevation of the ELA was 2586 m. The average elevation of the ELA in the Aras basin, Lake Urmia, and Sefidroud were respectively 2453, 2621, and 2685 m. The analysis of the findings showed that this unit was controlled by the glacial system during the cold periods.Discussion and conclusionSince the quaternary survey was about 12000 years ago, it was obviously impossible to accurately estimate the ELA, and there were inevitable differences in the estimated ELA by different methods. The highlands of the Northwestern geomorphic unit were located in the western, eastern and centeral parts. The Aras River, Lake Urmia and Sefidrud basins were located in this unit. The terrains’ direction of this unit was in six directions of north-south, east-west, and northeast-southwest. There was a possibility of the formation of a cirque glacial. 4059 cirques identified in this unit with the dispersion of 1,215 cirques in the Aras Basin, 1442 cirques in the Sefidrud Basin, and 1643 cirques in the Lake Urmia Basin. After the removal of pseudo-cirques (2720), remained the landform Cirques. The percentage of cirques was then estimated in different directions. The findings showed that while 71.25% of the identified cirques were in the Nesar slopes, 28.69% of them were in the Negar slopes. After identifying the cirque, the Wright method was used to estimate the ELA. By applying this method, in the first stage, the lowest ELA was estimated in the Aras Basin (1826 m). In the second stage, with the elimination of cirques pseudo-data, it was allocated to the Lake Urmia Basin (2360 m). Estimated ELA in different methods indicated that the ELA was less 232 m from the southern basin (Sefidrud) to the northern basin (Aras).

The Analysis of the Hydrological Droughts in the Northern Part of Lake Urmia

Jamshid Yarahmadi; G. Rostamizad

Volume 6, Issue 19 , September 2019, , Pages 79-100

Abstract

Introduction Hydrological droughts occur after meteorological and agricultural droughts. In other words, this kind of drought is the final stage of the drought cycle and is affected by global climate change. Nowadays, many studies on hydrological droughts are based on the Threshold Level method, which ... Read More Introduction Hydrological droughts occur after meteorological and agricultural droughts. In other words, this kind of drought is the final stage of the drought cycle and is affected by global climate change. Nowadays, many studies on hydrological droughts are based on the Threshold Level method, which is based on the Run Theory. According to this view, a drought is described as the length of a period in which hydrological variables, or discharges, are below the specified threshold level. To the researchers' knowledge, there have never been a major research on hydrological droughts in Iran and studies in this field are very limited in comparison with other types of droughts. Most of the researches in hydrological droughts have been done in the monthly and annual time intervals. However, the present study was conducted to investigate the hydrological droughts on a daily basis with the objectives of identifying and monitoring them and determining their occurrence and severity in the studied area. Methodology In this research, the Threshold Level Method was used to identify the hydrological droughts in the DaryanChai sub-basin in the northern part of Lake Urmia. Using the computer program NIZOWKA2003 based on the partial time series (PDS), the droughts in the hydrometric station of the Daryan during a thirty one year period (1982-2014) were calculated. Hydrological drought characteristics including time of occurrence, duration, severity, and minimum observed flow during dry period were calculated based on the NIZOWKA2003 software. In addition, frequency analysis, probability of the number of drought occurrences, duration, and volume deficiency in different return periods were calculated using the mentioned computer program. Here, the threshold level was chosen based on the flow duration curve (FDC), which was based on the daily flow rates of the selected hydrometric station and prepared using the NIZOWKA2003 program. The IC method was used to integrate the minor and mutual dependency periods of hydrological drought. Based on the characteristics of dry periods, the probabilistic distribution and frequency analysis of dry periods, the probability of the occurrence of drought and characteristics of dry periods (duration and volume deficit), fitting different types of statistical distributions and selecting the most suitable ones based on the fitting values (chi Score) were calculated using the NIZOWKA2003 computer program. Results The results of the calculations showed that a total of 38 periods of a hydrological drought occurred in this river. Approximately about 20 events from all detected drought occurrences lasted more than 200 days. The longest period of drought with 577 days lasted between the end of June 1988 and March 1990. Less than two months later, the second largest hydrological period with 365 days lasted between the beginning of May 1990 and the end of June 1991. Regardless of these two months, the largest hydrological drought period with 950 days was between 1988 and 1991. The severest hydrological periods were respectively 8987 and 6133 cubic meters, coincided with the largest hydrological drought periods. Moreover, the calculations showed that this river's water volume has fallen by 117 million cubic meters over the period of 31 years. Based on the results of Chi-square test and Akaya's criterion, Poisson distribution was the most appropriate distribution of the probability of the occurrence of drought occurrence. Among the various probabilistic distributions, Weibull's distribution was the most appropriate distribution of the duration of the hydrological drought events. Accordingly, the probability of the occurrence of a dry period of at least 13 day duration is likely to occur in this river. Additionally, the maximum observation dryness event of 578 days was estimated with a probability of non-exceeding 0.99 % at the Daryan hydro-station. The probable distribution of Weibull was selected as the most suitable distribution of the hydrological drought severity. Based on the Weibull method, the maximum water deficit volume was estimated at 13730 cubic meters with a low probability (0.01%). In contrast, the highest probability of the severity of drought (about 70%) in the Daryan Chai was estimated at 253,000 cubic meters. The results of the calculation of the return periods showed that in half of the cases, the probability of the occurrence of a dry period was with a duration of 170 days and an intensity of 2276 cubic meters with a 2-year return period. Discussion and conclusion Until the last decade, little research has been conducted on the hydrological droughts in Iran.In very few studies, the analysis of the low flows from the point of view of frequency analysis has been addressed.The lack or shortage of hydrometric data in many parts of the world has been the main limitation in hydrological drought studies. In this research, the Threshold Level Method was used to extract thehydrological dry periods and their characteristics. Despite the fact that this method has been extensively used in drought studies, its selection is still one of the controversial issues in such studies. Using the daily time series can provide complete and accurate information from the start and end dates of drought events. However, the use of this time basis in drought studies, especially hydrological droughts, is not common in the world and in Iran.The only studies in Iran, based on the daily time series, were conducted by Bayzidi and Saghafian (2011), Mesbahzadeh et al. (2017), and Mostafa Zadeh et al. (2018). Almost all other studies have been based on monthly or annual basis. However, the use of a daily time series is often associated with the problem of having minor andmutual dependency periods. There are several ways to overcome this problem. The Interevent Critria. (IC) is one of these methods which was used in this research.The efficiency of this method has been previously reported by Zelenhasićand Salvai(1987), Hisdal et al. (2003), Tallaksen et al. (2004), and Baiziidi and Bayzidi and Saghafian (2011).

Volume 11 (2024)

Volume 10 (2023)

Volume 9 (2022)

Volume 8 (2021)

Volume 7 (2020)

Volume 6 (2019)

Volume 5 (2018)

Volume 4 (2017)

Volume 3 (2016)

Volume 2 (2015)

Volume 1 (2015)

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