Sahar Daraei; Abdolreza Bahremand; Hamid Karimi
Abstract
The land use changes cause changes in components of the hydrological cycle and increase or reduce the amount of runoff. Subsurface runoff is one of the most important parts of the runoff in wet areas, especially in steepy lands with higher vegetation. Given the advantages and capabilities of distributed ...
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The land use changes cause changes in components of the hydrological cycle and increase or reduce the amount of runoff. Subsurface runoff is one of the most important parts of the runoff in wet areas, especially in steepy lands with higher vegetation. Given the advantages and capabilities of distributed hydrological models, these models are appropriate to assess changes in land use and quantitative estimates of changes. In this study, evaluation of the effects of land use change scenarios on the subsurface flow rate was investigated using WetSpa model on daily basis in Horo-Dehno Watershed with an area of 263.43 Km2. Daily hydro-meteorology data including evapotranspiration, precipitation and temperature from 2006 to 2010 were used to run the model, . The model input maps included DEM, land use and soil texture maps. According to the watershed potentials, four scenarios of land use change were planned in ArcGIS and entered in the calibrated model for simulation. In order to use model to simulate the effects of land use change scenarios, sensitivity and uncertainty analysis and calibration were performed manually and afterwards with the PEST optimization program. In addition, to compare the output hydrograph of subsurface flow in current situation of four scenarios with simulated results, changes in hydrological processes and parameters were evaluated. This analysis showed that improving land use is the reason of increasing of subsurface flow, increasing of deep infiltration, reducing of surface runoff and increasing of watershed time of concentration . Whereas, land degradation reduces the amounts of subsurface flow, permeability to deep and surface aquifers and increases runoff volume. Therefore, maintaining and improving current land uses are one of the major alternatives for watershed surface runoff management.
Mehran Lashanizand; Kianfar Payamani; Eraj Vyskarami
Abstract
Water shortage is one of the major problems in most countries, especially countries with a growing population and Iran is one of these countries. Iran is located in a hot and dry weather and its annual rainfall is one-third of the world. Water shortage and recent droughts have reduced available water ...
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Water shortage is one of the major problems in most countries, especially countries with a growing population and Iran is one of these countries. Iran is located in a hot and dry weather and its annual rainfall is one-third of the world. Water shortage and recent droughts have reduced available water resources. Therefore, managing agricultural water consumption should be considered as one of the most important headlines of water resources management. In this study, irrigation efficiency was computed after measuring water consumption of three agricultural products of wheat, clever and alfalfa.. Results showed that the highest and the lowest of efficiency index of 1.85 and 1.43 belong to alfalfa and clever respectively andirrigation water consuming efficiency were 61.9, 76.01 and 150.1 for wheat, alfalfa and clever, respectively. Also, results demonstrated that efficiency-added product index for all three products of wheat, alfalfa and clever were 6112.7, 6505.2 and 4870.3 Rial/m3, respectively. Finally, according to the result, alfalfa has the highest productivity compared to other products.
Hamzeh Noor; Amin Salehpour Jam; Seyed Hossein Rajai
Abstract
The degree of public participation in watershed management programs is a major determinant of success or failure of the programs, but the factors which make people participate still remain unknown. The main objects of current study are comparison evaluation of effective factors on preventing participation ...
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The degree of public participation in watershed management programs is a major determinant of success or failure of the programs, but the factors which make people participate still remain unknown. The main objects of current study are comparison evaluation of effective factors on preventing participation of rural societies in watershed management plans based on all people and experts’ viewpoints in Emarat Watershed of Khorasan Razavi Province. In the current study the effective factors on preventing participation of rural societies were classify in four classes include "economic", "educational-extension", "design-executive" and "social" indicators and 14 sub-indicators. Then the indicators and sub-indicators were prioritized using Fuzzy Analytical Hierarchy Process and Friedman Test. Finally, the two-sample Kolmogrov–Smirnov Test was also used to examine the agreement of the two views on the importance of the items. The results showed that, from the perspective of both groups of experts and peoples, economic indicator has a greater role in preventing people participation in relation to other indicators. The results of sub-indicators prioritization based on local people and expert’s viewpoints showed that “ignoring people´s income as a direct economic motivation” and “shortage of education of watershed residents about plants and their purposes”, respectively, were ranked as the most important sub-indices. The most important difference of the sub-indices from the perspective of local people and expert are related to the “ignoring people´s income as a direct economic motivation” and “lack of stakeholder’s consultation in the design and development of projects”. The overall conclusion is that considering the benefits of stakeholders, and multi-purpose projects and factors such as stakeholder consultation, and training of local communities can provide the basis participation of people in the watershed development projects.
Mohsen Zabihi; Seyed Hamidreza Sadeghi; Mehdi Vafakhah
Abstract
Soil erosion as a threatening phenomenon for the world population is mostly the result of the combined effects of unsuitable land use and climatic factors. Among climatic factors, rainfall is considered as one of the main causes of soil erosion and therefore detailed study of the different properties ...
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Soil erosion as a threatening phenomenon for the world population is mostly the result of the combined effects of unsuitable land use and climatic factors. Among climatic factors, rainfall is considered as one of the main causes of soil erosion and therefore detailed study of the different properties of rainfall such as rainfall erosivity is necessary. However, investigation of spatial variability of rainfall erosivity factor at different scales at national level has been less considered. Therefore, the present study aimed to investigate the spatial variability of rainfall erosivity factor in Universal Soil Loss Equation (USLE) for monthly, seasonal and annual scales in Iran. Towards this attempt, the amounts of rainfall erosivity factor were calculated through calculation of kinetic energy and maximum 30-minute intensity over 12,000 showers occurred at 70 stations in the study period of 20 years (1984-2004) in Iran. The spatial patterns of temporal variation were also in different time scales. According to the results, existing stations in the south west and north of the country had the first priority of annual rainfall erosivity factor hazard. The west and south west stations and south east stations had also the highest and the lowest seasonal and monthly risk rainfall erosivity factor, respectively. Also, results showed Tangpich in Khuzistan, Anzali in Giulan and Poleshalo in Khuzistan had the maximum rainfall erosivity factor whereas Bande Enherafi in Semnan, Tabas in South Khorasan and Bam in Kerman Provinces had the minimum annual rainfall erosivity factor hazard country wide. The average annual rainfall erosivity factor in the country was ultimately obtained 14.13 tm.ha-1.cm.h-1.
Tayeb Raziei
Abstract
In this research, the target area were regionlized into few distinctive homoginious sub-regions by applying principal component alalysis to the SPI time series at 3-, 6- and 12-months time scales and the resultant PC scores were considered as the regional SPI time series for drought forecasting using ...
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In this research, the target area were regionlized into few distinctive homoginious sub-regions by applying principal component alalysis to the SPI time series at 3-, 6- and 12-months time scales and the resultant PC scores were considered as the regional SPI time series for drought forecasting using time series modellingineach identified sub-region. The probability of occurences of dry, normal and wet events were also predicted for all the considered stations using Markov chain model and the results were spatially mapped and analysed. The expected drught numebr and drught length of the prediceted drought events were also estimated and mapped to spatially display their results in order to ease their spatial variability comparrison. Furthermore, different time series models were fitted to the Regional SPI series (PC scores) to identify the best fitted model for each region in order to use for drought forcasting. The result shows that the ARMA is the best fitted model for SPI time series at 3- and 6-months time scales while for the 12-months time scales the SARIMA model is the best fitted model. Using the identified models the magnitude of the SPI was forcasted for the leading times. The result shows that the time series models can favorably forcast SPI values for three months ahead, wherease the predicted results for more than three months ahead is not reasonably accurate.
Payam Amouzegari; Mostafa Panahi; mir khalagh mirnia
Abstract
Groundwater resources are the most important source of fresh water in the world. In Iran which is located in the arid and semi-arid region, mismatch of consumption needs with rainfall time along with climate change has increased the demand for groundwater. Excessive extraction of groundwater in the Alashtar ...
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Groundwater resources are the most important source of fresh water in the world. In Iran which is located in the arid and semi-arid region, mismatch of consumption needs with rainfall time along with climate change has increased the demand for groundwater. Excessive extraction of groundwater in the Alashtar Watershed reduced the water level in the aquifer of the plain and water resources of this area have faced a negative balance. Due to the inherent limitations of the country's water resources and increasing the split between supply and demand, the use of economic instruments and the establishment of the water market for optimal allocation of groundwater is a necessity. Accordingly, this study in order to determine the market price of groundwater with the aim of accurately identifying the local markets for groundwater and also measure the views of local water market operators about some of the strategies for advance the water market designed and implemented. The statistical population in this research was all rural exploiters are the main reservoirs of groundwater in the basin who contribute to the buy and sale of these resources. Regarding market prices in the study area, the average price of groundwater was 1,749 Rials per cubic meter, and the total value of groundwater was estimated as 555,307.5 Milion Rials. The results showed that in 103 villages there is a market for the buy and sale of groundwater. Those villages that have a local groundwater market, 76% of the villages have been established by creating popular organizations and the water regulatory council and 43% of the villages by create a bulletin board agreed to facilitate the buy and sale of groundwater resources.
Eqbal Mohammadi; Ali Akbar Mehrabi; Baharak Motamedvaziri
Abstract
Introduction
The requirement of a comprehensive water law is the drafting and revision of laws and the scientific and legal regulation of water distribution laws. The idea of a comprehensive law is consistent in many countries to eliminate the fragmentation of laws. The comprehensive water law means ...
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Introduction
The requirement of a comprehensive water law is the drafting and revision of laws and the scientific and legal regulation of water distribution laws. The idea of a comprehensive law is consistent in many countries to eliminate the fragmentation of laws. The comprehensive water law means the thematic examination of the laws and legal rules related to water, the realization of which requires spending a lot of time. Lack of water resources and drought, increase in population and excessive consumption of water, the existence of vague and unenforceable laws in the water sector are among the most important challenges of the country, and for the fair allocation and implementation of the correct management of the protection of water resources in watersheds, it is necessary to formulate a comprehensive water law. Failure to examine the legal position of environmental rights, as the cause of destruction of wetlands in Iran on the one hand and the indiscriminate use of river water on the other hand, causes various changes in the water flow regime and destruction of the river ecosystem and It has become wetlands and it shows the importance of drafting a comprehensive water law in Iran. The results of clarifying and drafting a comprehensive law will lead to an increase in social security and public welfare. Failure to pay attention to this type of research will lead to an increase in injustice, destruction of water and soil resources, loss of national rights and rights of people, and destruction of the environment. The purpose of the research is to examine the water laws in Iran in order to solve legal challenges and provide the basis for the development of the country's comprehensive water law.
Materials and methods
Research materials and methods include collecting statistics and information on water laws and identifying and separating the main and secondary laws related to water, valid ruling laws from non-valid ruling and obsolete laws, and examining the thematic, conceptual relationship and analysis of water laws from a legal and structural point of view. An organization that includes the statistical population of all laws enacted during the legislative period from 1906 to 2021. In this research, a list of the main and secondary water laws, including valid and obsolete laws and expired, rejected and conflicting laws, was prepared in the form of tables and histograms, and based on the reference, ID number and date of approval, it was collected and analyzed from library and internet sources. It was conducted qualitatively in the form of theoretical framework, content analysis and conceptual model, and the parameters of the number of obsolete, conflicting, expired, repealed and valid ruling laws were quantitatively analyzed.
Results and discussion
The research results show that out of 364 water-related laws, only 6.6% are in the form of statutes and about 21.7% are valid laws. 30% are related to protocols, agreements, conventions and contracts. 6.6 percent of the laws of the water sector are explicitly and implicitly repealed, 6% are expired and 29.1% of the existing laws are repealed, which can often be repealed during the revision process and will provide the basis for the development of the country's comprehensive water law.
Conclusion
The analysis of the questionnaire also shows that 95% of the respondents by choosing a very high option and 5% by choosing a high option consider it necessary to revise the comprehensive water law. Among the respondents, 89% believe that the drafting of the comprehensive water law has an effect on attracting people's participation in preserving water resources and watershed management. Therefore, the answer to most of the questions is affirming the necessity of developing a comprehensive water law.
Jafar Rezaei; Heydar Seydzadeh; Alireza Shadmani
Abstract
Flood control, artifcial feeding of ground water aquifers and effort to optimize the productivity of natural resources are component the most results that have gotten from implementation of spreading project in spreading statious of country. One of the most important goals of spreading is the creation ...
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Flood control, artifcial feeding of ground water aquifers and effort to optimize the productivity of natural resources are component the most results that have gotten from implementation of spreading project in spreading statious of country. One of the most important goals of spreading is the creation of positive changes in economical variables of area including agricultural and rangeland productionsand their development. In other words, each of spreading projects implemented in different stations have specific economical effects in desired area. The goal of this project is determination of economical effects of floodwater spreading project on Dehloran aquifer through monitoring and surveying its behavior and recording relevant data steadily. For this purpose, profit ability and economical justification of the project have been determined through economical indicator evaluation of projects. Results demonstrated that irrigated lands of downstream villages have been inceased 3.5 times in 2010 compared to the year1995. The added value of the injected floodwater was estimated to be 14.6 billionRial. The added value of rangeland products was about 1353.96 billion Rial. The added value of wood production was estimated about 13.38 billion Rial. The added value of agricultual products was about 657.05 billion Rial. NPV, ROR and B/C of the project were 1398.61 billion Rial, 0.38 and 2.87, respectively that show economical justification of the project.
Ali Khodaie; Rahman Zandi
Abstract
Occurrence of numerous floods in different regions of the country has always caused a lot of damages in various fields. Therefore, it seems necessary to prepare and compile a comprehensive plan in the field of flood control. The study area is influenced by the Mediterranean climate and within the radius ...
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Occurrence of numerous floods in different regions of the country has always caused a lot of damages in various fields. Therefore, it seems necessary to prepare and compile a comprehensive plan in the field of flood control. The study area is influenced by the Mediterranean climate and within the radius of the Caspian and Caucasian climates. Due to the high altitude differences, it has a variety of climates and high variability in rainfall, and known as one of the areas exposed to destructive floods. The purpose of this study is to identify flood prone areas based on multi-criteria decision making and neural network model in Khodaafarin Watershed. For this purpose, according to the factors affecting the occurrence of floods, the information layers of the region including Curve Number (CN), Gravilius coefficient, runoff height, precipitation, distance from waterway, soil retention, waterways, slope, drainage density, geology and vegetation, according to the study of maps, reports, satellite images and field surveys. In order to weight the criteria in the present study, network analysis method (ANP) and Super Decisions software were used. The factor of runoff height with the amount of 0.241, slope with the amount of 0.207 and precipitation with the weight of 0.169 were the most important in relation to flood occurrence. Finally, by combining these layers according to their weight in the GIS environment, a flood risk zoning map was extracted in five classes. The results also showed that, 43 square kilometers (3% of the area) of the watershed is in the very high flood risk class and 288 square kilometers (18% of the area) in the high flood risk calss. More than 21% of the area is among the areas with high and very high flood potential. Therefore, it seems that the need for surface water management in the region in order to prevent floods and the proper use of water in the region is necessary.
Zarin Foroughi; Siyavash Shayan; Parviz Kardavani
Abstract
The human interventions role, particularly land use changes, is investigated in this research in Kor River hydromorphologic state (upstream of Dorudzan Dam, Fars). Within the steps of this research, there are discrete methods frameworks such as hydrologic model using HEC-HMS, to investigate the effect ...
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The human interventions role, particularly land use changes, is investigated in this research in Kor River hydromorphologic state (upstream of Dorudzan Dam, Fars). Within the steps of this research, there are discrete methods frameworks such as hydrologic model using HEC-HMS, to investigate the effect of land use changes on flood characteristics and Rosgen geomorphologic evaluation model to investigate the effect of land use changes s on environmental resources and geomorphologic changes of the river. Results of hydrologic studies by HEC-HMS indicated that in the studied time interval, the number and the value of peak discharges are increased and the delay time and concentration time are reduced. Through simulation results for 1993-2013, this indicated that land use changes have increased the amount of flood discharge by 15% in this region and these findings are corresponds with observed floods. The results of Rosgen geomorphologic evaluation model, indicated that during studied time interval, maximum hydromorphologic changes in level 1 and 2 of Rosgen model were related to spatial ranges 1 and 2 and then ranges 4, 5 and 3 followed. In all studied spatial intervals, there are numerous transversal and longitudinal changes due to erodible boundaries and maximum changes are related to 2, 1, 3, 4 and 5 spatial intervals, respectively. The transversal changes were due to slope change, hydrologic regime, suspended and bed load, aggression to riparian lands and constructing dams.
Mohammad hossein Nassajian Zavareh; Hossein Malekinezhad; Mohammad reza Ekhtesasi; Mohammad Zare
Abstract
The increasing exploitation of groundwater reserves and consequently the drop in the water level and reduction of the reserves have seriously caught the attention of officials and planners to the integrated management of groundwater and surface water resources. The evaluation and management of water ...
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The increasing exploitation of groundwater reserves and consequently the drop in the water level and reduction of the reserves have seriously caught the attention of officials and planners to the integrated management of groundwater and surface water resources. The evaluation and management of water resources are considered as one of the key factors in comprehensive development. Boein Aquifer in Isfahan Province located in the Gavkhooni Basin is studied in this study. The Standard Precipitation Index (SPI), Reclamation Drought Index (RDI) and Groundwater Standard Index (GRI) in the time scales of three, six, 12, 24 and 48 months and Cultivated Land Index (CLI) in annual time scale are calculated. Results showed that the highest correlation between the SPI and GRI is in 18 and 24 months' time scale, and there is a delay of 1.5 to 2 years between these two droughts. Contrary to the results of some references, the correlation between meteorological drought index and GRI does not always increase with increasing the time scale. A synchronic study of the SPI, GRI and CLI shows a large difference between the SRI and the other two indicators in 2004-2008 periods that may be related to the poor management of the region. However, more close values obtained for these three indices in the recent years mainly due to the better management of water consumption by relevant organizations. To determine homogeneous drought regions, different combinations of temporal and spatial scales were used by creating 39 different scenarios and running 390,000 simulations. None of the heterogeneity measures were met in 90% of cases. This indicated that the linear moment technique is not a suitable method for determining homogeneous arid regions of groundwater probably due to the non-random data. Therefore, the linear moment technique will be more useful if the data is random.
Ashkan Banikhedmat; hosein salehi; saeed golian; farshad koohian afzal; nazanin ezati boorestan
Abstract
Introduction
One of the methods for estimating the amount of runoff resulting from precipitation is the use of hydrological models. The SWAT model is one of the widely used tools for simulating the quantity and quality of water at the watershed level. This model is a conceptual model that is capable ...
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Introduction
One of the methods for estimating the amount of runoff resulting from precipitation is the use of hydrological models. The SWAT model is one of the widely used tools for simulating the quantity and quality of water at the watershed level. This model is a conceptual model that is capable of simulating large watersheds with different management scenarios. One of the major challenges of this model and many other hydrological models is the calibration of effective and sensitive parameters for estimating the amount of runoff. In general, calibration methods can be divided into two groups: manual and automatic. Manual calibration of a model requires the modeler to have a good understanding of the model's physics. On the other hand, due to the time-consuming nature, existing complexities and the development of new optimization algorithms, nowadays automatic calibration has gained more attention. Automatic calibration is based on three components: the objective function, the optimization algorithm, and the station information. The use of a single objective function in model calibration may lead to an increase in error in other aspects of the simulation. Scientific experience in single-objective calibration has shown that no single objective function, even with high efficiency, can accurately represent all the characteristics and properties of a watershed. Therefore, the use of an appropriate optimization algorithm to improve calibration results includes the use of multiple objective functions to identify a set of efficient solutions.
Materials and methods
The study area is located in the western part of Iran, in Kermanshah Province, with an area of 5467 square kilometers. The minimum and maximum elevations in the area are 1275 and 3360 meters, respectively. The average precipitation in the watershed is about 505 mm, with the highest rainfall occurring in the months of November and Decemeber, and the lowest rainfall in the months of Julay and August. The main rivers in this watershed are Mark, Gharehsoo, and Razavar. In this study, the SWAT rainfall-runoff model was calibrated using the NSGA-II algorithm under three calibration scenarios. For model calibration, the first scenario used the NSE objective function, which focuses on maximum flows. In the second scenario, to focus on minimum flows, the logarithmic transformation of the simulated and observed streamflow series was used, and the NSE efficiency coefficient was adopted as the objective function, represented as LogNSE. The third scenario was a combination of the first and second scenarios, where the non-concordant objective functions NSE and LogNSE were used simultaneously.
Results and discussion
The results of this study showed that based on the NSE evaluation index values (0.83, 0.74 and 0.83 for the first to third scenarios) and the model overestimation and examination of the flow graph in the first scenario, which showed a tendency towards higher flows, this scenario would be more efficient in estimating maximum flows. Additionally, considering the LogNSE evaluation index (0.69, 0.74 and 0.72 for the first to third scenarios), the second scenario with the LogNSE single objective performed better in minimum flows. However, the model constructed using two non-concordant objective functions aimed to achieve a balance and showed satisfactory performance in simultaneously estimating maximum and minimum flows.
Conclusion
In general, it can be concluded that if the objective of the study is to investigate maximum and minimum flows, such as flood or drought studies, single-objective algorithms will perform better. However, if the objective is to control the water balance and achieve satisfactory performance of a model in both maximum and minimum flows, a two-objective scenario with a non-concordant approach can yield better results compared to single-objective algorithms.
Rahim Kazemi; Jahangir Porhemmat; Forood Sharifi
Abstract
The Flow Duration Curve (FDC) is a classical method used to graphically represent the relationship between the frequency and magnitude of stream flow and is required as a prerequisite for water resources management projects. In this study, by analyzing daily data of hydrodynamic stations, 47 stations ...
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The Flow Duration Curve (FDC) is a classical method used to graphically represent the relationship between the frequency and magnitude of stream flow and is required as a prerequisite for water resources management projects. In this study, by analyzing daily data of hydrodynamic stations, 47 stations with the appropriate statistics and the common period between 1976 and 2011 was selected in a semi-arid region of the country. Using a topographic map with a scale of 1: 50000 and determining the position of the stations, the study area was determined and 11 physiographic parameters influencing the flow duration curve including: average height, basin area, gravilillus coefficient, basin slope, main river length and hydrological parameters including annual rainfall, Base flow index, hydrograph recession constant, curve number, permeability and the number of rainy days were extracted for each basin. The flow duration curve indices were then extracted using daily flow data. Then factor analysis was performed and independent factors influencing the flow duration curve were determined. Finally, homogeneity was performed based on independent main factors and the regression relations of the curve indices were extracted in each homogeneous region.In order to investigate the validity and accuracy of the models in homogeneous regions, error-independent test methods, normal distribution of errors and control stations were used. The results showed that the selected factors for factor analysis in semi-arid climatic zone (75.875 percent) of the variance of data were explained. The six parameters of precipitation, curve number, slope, rainy days, permeability and area were known as the most effective parameters. The results of the accuracy assessment of the models using the control stations showed that the relative error of the relations presented in the homogeneous region was 0.17, 2.17, 2.73, 1.53 and 1.94, respectively. The normal distribution of errors, the coefficient of determination of more than 0.90 and the Durbin Watson coefficient between 1.5 to 2.5 also Nash-Sutcliff near "one" indicate the reliability of the regression relations presented for estimating the flow duration curve indices in the ungagged catchments in semi-arid areas of the country.
Fahimeh Razi
Abstract
Long meteorological drought can lead to the onset of hydrological drought. In this research, the lag time between the two types of drought was investigated for determining the hydrologic drought onset after realizing the climatological drought. This is a matter to provide managers with enough time for ...
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Long meteorological drought can lead to the onset of hydrological drought. In this research, the lag time between the two types of drought was investigated for determining the hydrologic drought onset after realizing the climatological drought. This is a matter to provide managers with enough time for decision making before the occurrence of water shortage in the watershed. The SWAT water balance model was used to determine and predict the lag time between the two types of drought for Foomanat (Anzali wetland) watershed in Gilan province Due to the ability to simulate the long-term flow of representative rivers in the basin. The OAT method was employed for the sensitivity analysis of the water balance model. Among the parameters used in SWAT, three parameters including curve number, available water, and the evaporation compensation factor in the soil were recognized as the most effective parameters for the results of the model. Calibration and validation of SWAT were performed using SCH model. The calculated Nash-Sutcliff and correlation coefficient in estimating runoff as well as determining and predicting the lag time between the two types of drought by SWAT were acceptable. The Nash coefficient was obtained as 0.68 and 0.8 for calibration, and 0.65 and 0.79 for validation periods, respectively. Using the calibrated model, one can predict the water balance situation and the lag time between the onset of meteorological drought and the emerging hydrological drought in the watershed for any interested meteorological drought scenarios. Based on the results, the chance of having a one -month lag time, is more than 70 percent, while the chance of a 2-month lag time in the Foomanat watershed Anzali wetland) is more than 23 percent.
Saeedeh Nateghi; Elham Rafiiei sardooi; Ali Azareh; Farshad Soleimani Sardoo
Abstract
Changes in water cycles in different parts of the world is one of the effects of climate change in recent decades. Evapotranspiration, as the part of the hydrological cycle, will also undergo these changes. Therefore, in the present study, the effect of climate change on potential evapotranspiration ...
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Changes in water cycles in different parts of the world is one of the effects of climate change in recent decades. Evapotranspiration, as the part of the hydrological cycle, will also undergo these changes. Therefore, in the present study, the effect of climate change on potential evapotranspiration changes in Halilrood Watershed, under RCP2.6, RCP 4.5 and RCP 8.5 scenarios using LARS-WG downscaling model and the output of the general circulation model of HadGEM2 in future (2021-2040) was studied and the rate of evapotranspiration at the basin scale was calculated based on the predicted climatic parameters using Tornthwaite method in future. According to the results of the LARS-WG model, in the study area, precipitation will decrease and the temperature will increase under all scenarios in future compared to the baseline period. Evapotranspiration will also increase based on the predicted temperature and precipitation. So that, at the basin scale, evapotranspiration will increase by 3.4, 6.8 and 8.5 under RCP 2.6, RCP 4.5 and RCP 8.5 scenarios in future (2040-2021), respectively. According to the results, the highest increase in temperature and evapotranspiration and the highest decrease in precipitation at the basin scale is related to the RCP 8.5 scenario. The results of this study can be used in studies related to water resources management, agricultural and environmental studies.
Hasan Alipoor; Arash Malekian
Abstract
The precipitation is important factor among climatic factors and factors that affect on hydrology and water balance of a watershed and prediction of its behavior is very important for ecosystem management and water resources. In this study, long-term precipitation threshold trend was assessed using Non-parametric ...
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The precipitation is important factor among climatic factors and factors that affect on hydrology and water balance of a watershed and prediction of its behavior is very important for ecosystem management and water resources. In this study, long-term precipitation threshold trend was assessed using Non-parametric statistical approaches (Spearman Rho, Kendall's Tau, Mann-Kendall and Sen's slope Estimator) and Homogeneity tests (Von Neumann, Buishand, Standard normal homogeneity and Pettitt) at eight synoptic stations during 1984 to 2013 in north-west Iran. According to the results of non-parametric and homogeneity tests, all precipitation thresholds had decreasing trend at 0.01 significant level and showed sudden descending changes at 0.05 significant level in Maragheh station. Mann-Kendall, Spearman and Kendall's Tau tests together provided similar results in all series that were different by Sen method results in some thresholds. These means that all precipitation thresholds have trend by 26% of non-parametric tests, in order to determine change point of precipitation thresholds. Buishand, Standard normal homogeneity and Pettitt tests provided similar results that were different with Von Neumann results in all thresholds. In this research, 25.92 percent of precipitation threshold was heterogeneous in the study area by studying these sudden changes. It was found that natural and unnatural factors including meteorological droughts or human factors have caused sudden changes in precipitation threshold.
Abdorrahim Fazeli khiavi; Bromand Salahi; Masoud Goodarzi
Abstract
Climate change is an effective phenomenon on many natural processes, including hydrologic cycle. The evapotranspiration as one of the parts of the hydrologic cycle will be at the forefront of these changes. Due to the importance of evapotranspiration in water resources management and agricultural planning, ...
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Climate change is an effective phenomenon on many natural processes, including hydrologic cycle. The evapotranspiration as one of the parts of the hydrologic cycle will be at the forefront of these changes. Due to the importance of evapotranspiration in water resources management and agricultural planning, the present study was conducted to investigate the effect of climate change on this parameter in Moghan Plain. For this purpose, the HadGEM2 atmospheric and oceanic circulation model was used under RCPS and Lars-WG6 downscaling in 2011-2030 and 2030-2060 periods. Also, Penman-Monteith and Hargreaves-Samani methods were used to calculate evapotranspiration. This study showed an increase of 6 to 8.4% of calculated evapotranspiration with Penman-Monteith method in each of the scenarios in 2030-2011 and 2030-2060 periods compared to the observed years. Also, calculated evapotranspiration of the Hargreaves-Samani method will increase from 4.5 to 7.7% in each scenario in 2030-2011 and 2030-2030 periods compared to the observation years. These increases affects on water demands of Moghan and Khodafarin irrigation and drainage networks in the maximum months, which requires appropriate solutions to adapt to climate change conditions.
Saman Javanroodi; Mohammad Mahdavi; Baharak Motamedvaziri
Abstract
In order to determine the role of hydrological statistic data periods on flood forecasting in Sefidrood Watershed, maximum daily flows were collected from hydrometric stations, thus seventeen valid stations with long-term statistical data period was chosen and in some cases which data were corrupted, ...
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In order to determine the role of hydrological statistic data periods on flood forecasting in Sefidrood Watershed, maximum daily flows were collected from hydrometric stations, thus seventeen valid stations with long-term statistical data period was chosen and in some cases which data were corrupted, data has been reproduced by considering common time base.. At the second step, maximum daily flow data have been divided in to statistic series with 10, 15, 20, 25, 30 and more than 30 years data periods. Fitting statistic distribution of Normal, Normal log, Normal log 2 parameters, Normal log 3 parameters, Pearson log 2, Pearson log 3 and Gamble were determined by “Smada” software, also flood with two, three, five, 10, 25, 50, 100 and 200 return periods were calculated either. Statistic distribution for all of seventeen hydrometric stations were determined separately with RMSE method in Excel and SPSS for maximum daily flow.. Regarding zero-error in forecasted floods for long statistic data period (more than 30 years) in related return periods, compared with short statistic data period (10, 15, 20, 25 and 30 years), flood’s estimated error was calculated for all stations. In general, results indicated that increasing of statistic period, will enhance the accuracy of forecasting in hydrometric stations, and applying short-term data period will result in high levels of error.
Aliakbar Abbasi
Abstract
Investigations show that in some cases the distance between check dams are decreased due to wrong ultimate slope. In this Study, a survey and investigation implemented on Gush and Bahreh catchments, Kartian, Kameh and Dasht watersheds which are located on upstream of Kardeh, Torogh, Shahid Yaghubi and ...
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Investigations show that in some cases the distance between check dams are decreased due to wrong ultimate slope. In this Study, a survey and investigation implemented on Gush and Bahreh catchments, Kartian, Kameh and Dasht watersheds which are located on upstream of Kardeh, Torogh, Shahid Yaghubi and Golestan dams, respectively. In this way, longitudinal section profile, ultimate slope, location, distances and height of dames with acceptable performance about upstream ultimate slope has been measured. Meanwhile, characteristics related to bed aggregates has been sampled and determined. Then, with the measure of dimensions regarding the ultimate slope, some equations which were based on primary slope of river direction has been developed. Our investigations claim that unsuitable design in ultimate slope had been lead decreasing the distances between dams; consequently, some of upstream weirs had been buried under sediments. To wrap it up, we have to argue that definition of distance between dams based on the measured ultimate slope could result 25.4 percent descend in expenses of all studies weirs and dams construction and protection.
Aliasghar Alesheikh; Zahra Chatrsimab; Behzad Vosoghi; Mahdi Modiri; Mohammad Sadegh Pakdaman
Abstract
Earth's subsidence is one of environmental hazards that humankind faces in recent decades due to the extraction of groundwater resources in the plains. Over the past years, the desertification of plains in Iran has caused a great deal of economic and social damages to the country due to the decline in ...
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Earth's subsidence is one of environmental hazards that humankind faces in recent decades due to the extraction of groundwater resources in the plains. Over the past years, the desertification of plains in Iran has caused a great deal of economic and social damages to the country due to the decline in groundwater levels. Marvdasht Plain Aquifer has been significantly affected by this phenomenon in recent years. On the other hand, considering the location of historical monuments like Persepolis in this village, the issue of subsidence checking is important. Therefore, the present study investigates the relationship between the amount of groundwater extraction and subsidence situation in this region. In this study, Kriging statistical method was used to study the changes in groundwater level, and radar differential interferometry and COSMO-SkyMed radar images were used to estimate the rate of subsidence. Results showed that the average annual groundwater loss is 45 centimeters. On the other hand, the highest rate of subsidence in the oblast area is between 2.5 centimeters and about 15% of the area has a subsidence of less than one cm in the period from 2013/10/01 to 2014/02/01. Comparing the map of the groundwater level and the map of the earth's surface displacement, showed that the areas with the highest groundwater abundance have the highest displacement and ground falls about one cm for every 45 cm of groundwater level drop. Comparison between amplitude and subsidence pattern obtained from the results of radar interferometry technique with location, the density of wells and groundwater abstraction in this plain shows that subsidence has occurred in the same areas where the density of these wells and extraction of groundwater resources is high.
Mohammadtaghi Sattari; Mohammadreza Abdollah Pourazad; Rasoul Mirabbasi Najafabadi
Abstract
Floods are the main natural disasters that produce serious agricultural, environmental, and socioeconomical damages in many parts of the world. Accurate estimation of river flow in streams can have a significant role in water resources management and in protection from possible damages. This study aims ...
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Floods are the main natural disasters that produce serious agricultural, environmental, and socioeconomical damages in many parts of the world. Accurate estimation of river flow in streams can have a significant role in water resources management and in protection from possible damages. This study aims to compare the abilities of Support Vector Machine (SVM), M5 model trees and Linear Regression (LR) methods in forecasting hourly discharge flow of Aharchay River. The hourly water level-discharge and 14 flood events data of Aharchay River measured at the Tazekand hydrometric station was used for modeling. The results showed that the SVM method gives more accurate results than the M5 model and LR method in forecasting river flow for next one and two hours with the R2=0.96 and RMSE=0.0472 (m3s-1) and the R2=0.90 and RMSE=0.1596 (m3s-1), respectively. Comparing the performance of SVR and M5 models indicated that, however the SVR approach may present more accurate results than the M5 model tree, but the M5 model provides more understandable, applicable and simple linear relation in forecasting hourly discharge. Thus, the M5 model tree can be used as an alternative method in forecasting hourly discharge.
fatemeh bayati; rasoul mirabbasi; Roohollah Fatahi Nafchi; mahdi radfar
Abstract
One of the most important challenges of researchers in rainfall-runoff modelling is the estimation losses and extracting excess rainfall, which can affect on accuracy of the model and hydrograph characteristics. In the present study, at first the infiltration index of was estimated based on the depth ...
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One of the most important challenges of researchers in rainfall-runoff modelling is the estimation losses and extracting excess rainfall, which can affect on accuracy of the model and hydrograph characteristics. In the present study, at first the infiltration index of was estimated based on the depth of runoff and rainfall and also effective rainfall time. Then, instantaneous unit hydrograph was computed through Russo Method and the dimensions of direct runoff hydrograph were determined for 20 rainfall- runoff events. Then in order to increase the precision in estimating the dimensions of obtained hydrograph, the value of penetration index was estimated based on bivariate distribution resulted from infiltration index and one of rainfall characteristics which obtained from Copula function. For this purpose, at first the correlation between infiltration index of , characteristics of rainfall hyetograph and runoff hydrograph was calculated, then the best- fitted marginal distribution on each variable was specified. Finally, Galambos function was chosen as the best copula function for creating bivariate distribution for pairs of infiltration index of and rainfall height, infiltration index of and maximum velocity, infiltration index of and average flow and also infiltration index of and velocity. Therefore, the hydrograph dimensions were obtained for each event. Comparing the various dimensions of computed and observed hydrograph by copula function in Russo method showed that the infiltration index of can be estimated more accurately by using the copula function.
Amirhossein Halabian; Nasrin Nikandish; Motahare Akbari
Abstract
In the present study is to identify patterns causing floods in the Mazandaran province to predict these patterns through before the flood could necessary precautionary measures to prevent the damage and take advantage of precipitation. In this reserch, two databases composed of two variables is necessary. ...
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In the present study is to identify patterns causing floods in the Mazandaran province to predict these patterns through before the flood could necessary precautionary measures to prevent the damage and take advantage of precipitation. In this reserch, two databases composed of two variables is necessary. a group of variables and atmospheric data including geopotential height at 500 hPa, zonal wind(uwnd), meridional wind(vwnd) and specific humidity(shum) in Synoptic four hours in the range 0 to 80 degrees north and 0 to 120 degrees east at a spatial resolution 2.5 × 2.5 degree from the database (NCEP / NCAR) have been harvested and other group of precipitation and discharge data in area, during the is 28 Aban to 2 Azar 1388. Then, taking advantage of environmental- circulation approach to mapping 500hpa circulation patterns, atmosphere thickness patterns of the levels1000-500 hPa, moisture flux convergence function and frontogenesis function in 500,925 and 1000 hPa levels on the occurrence of floods. The results of this research have shown that flood generating precipitation in the Mazandaran area are mainly caused by the eastern Mediterranean frontal lows. At the same time, thickness patterns have illustrated intense depressure zone that caused by meeting of cold air mass of the high latitude with humid and hot air mass of the southern Mediterranean. Analysis of the moisture flux convergence(MFC) patterns also have shown that flood generating precipitation are caused by moisture flux of water masses of the Caspian Sea and Black Sea to the Mazandaran area. Analysis of the frontogenesis function maps indicate that occurrence of flood generating precipitation in the study area is caused by the formation and occurrence of front in the Caspian sea and the Black sea in middle levels and east these two of water masses at lower levels of atmosphere (925 and 1000 hPa).
Nader Heydari
Abstract
Karkheh watershed is located in the western to southwestern region of Iran and in a dry to semi-arid region. The existence of different agricultural systems, including irrigated and rainfed agriculture, low water efficiency, the existence of production limitations (salinity and drainage management in ...
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Karkheh watershed is located in the western to southwestern region of Iran and in a dry to semi-arid region. The existence of different agricultural systems, including irrigated and rainfed agriculture, low water efficiency, the existence of production limitations (salinity and drainage management in the downstream), poverty and lack of livelihood of local communities (upstream), the issues of upstream-downstream impacts of the basin, environmental issues, etc., led to the proposal of the Karkheh watershed as a suitable model in the country for the CGIAR Global Water and Food Challenge Program (known as CPWF). Therefore, this basin was chosen as one of the representative watersheds among the other nine watersheds of this global program, as a model for arid and semi-arid regions of the world, and the program was implemented during phase one of the program (2004 to 2008). In the implementation of this program, approaches, organization and mechanism, management structure, technical and program criteria, basin management principles, stakeholders' participation, innovations and ways of presenting outputs, in different stages of basin selection, program start and during The implementation of projects approved by the program were adopted and used. The main objective of this article is to document the methodology used during the process of implementing the CPWF international research and development program in the Karkheh Basin, so that its hidden knowledge is revealed, related experiences and achievements are documented, and used for future uses in other similar projects in this or other basins in the country. The study method is mainly based and derived from the study and analysis of program documentation archives, reports, discussions held during the meetings, the results of workshops and national and international conferences and the reports of the field visits carried out during the implementation of the global CPWF program and the implementation of this program in Karkheh basin. Among the important achievements and methodologies and the documented indicators of the program, one can include the methodology of collaborative development of technologies, the examination of the paths of project results, the criteria for selecting research sites, and the methodology for determining the principles of integrated watershed management which are presented and explained in detail in this article.
Aboalhasan Fathbabadi; Mahnaz Kohneshin; Ali Heshmatpour; Masome Farasati
Abstract
During last decades hydrological models were extesively used in rainfall-runoff modeling. These models contain some constant parameters that must be optimized through appropraite mthods. In addation to model structur, the efficieny of hydrological models depend on these optimized parameters. In this ...
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During last decades hydrological models were extesively used in rainfall-runoff modeling. These models contain some constant parameters that must be optimized through appropraite mthods. In addation to model structur, the efficieny of hydrological models depend on these optimized parameters. In this study, the efficiency of three automatic optimizing algorithms including Dynamically Dimensioned Search (DDS), Shuffled Complex Evolution and Genetic algorithms in calibration lumped hydrological model HyMod in Ghorchay Ramian Catchment were investigated. For these mehods, convergence speed and variability of final optimized values were investigated. Results showed that Genetic algorithm converged faster than two other methods. Following, DDS algorithm converged faster than Shuffled Complex Evolution algorithm. Shuffled Complex Evolution and Genetic algorithms took shorter and longer time per each epock, respectively. Highest and the least variability of final results were obtained for DDS and Shuffled Complex Evolution algorithms, respectively. With respect to final results variability, Shuffled Complex Evolution algorithm was more satable and had better performance than other methods. Using analyse variance and comper means in Shuffled Complex Evolution algorithms for complexes less than 12, the model performance was increased as the number of complexe increased. As alpha value increased, the model performance decreased and model had the best performance at the value of 0.58. Conversely, model performance was increase as beta values increasd and the best perfromnce was obtained for beta equal to 1. For Genetic algorithm, the best performance was obtained when the value of values crossover, mutation and chromosome number was equal to 0.2 and 0.3 and 16, respectively.
