watershed
Masoud Motaghian; Reza Ghazavi; Seyed Hassan Alavinia
Abstract
Comprehensive management is a new concept and a new approach in planning, development, management of water resources and vegetation with special emphasis on economic, social and environmental issues. The purpose of this research is to present the comprehensive management strategies of the Dubai Basin ...
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Comprehensive management is a new concept and a new approach in planning, development, management of water resources and vegetation with special emphasis on economic, social and environmental issues. The purpose of this research is to present the comprehensive management strategies of the Dubai Basin using the SWOT model and determine the implementation priority with QSPM. For this purpose, first the weaknesses, strengths, opportunities and threats of the studied basin were extracted using the brainstorming method and group decision-making for the Doabi watershed in Tehran province, and then the relative importance and final value of each factor in the matrix was determined and analyzed. In order to prioritize the strategies, the QSPM matrix was also used. The results of this study showed that the component of the presence of springs, aqueducts and rivers in the basin with a weight of 0.24 as the most important strength, two weak components of lack of water and humidity in the downstream areas of the basin and low rainfall in the outlet area of the basin with a weight score of 0.24 as The most important weak points, the component of grade 1, 2 and 3 asphalt and dirt roads with a weight of 0.16 have been identified as the most important opportunity and the component of flood and its resulting damages with a weight of 0.18 as the most important threat. The results also showed that the evaluation matrix of internal and external factors was 3.15 and 3.16, which indicated the dominance of strengths over weaknesses and opportunities over threats. In other words, the Doabi watershed is in an aggressive strategy. In order to manage opportunities and strengthen those, strategies were proposed and based on the QSPM matrix, management operations were placed as the first priority and biological operations were placed as the second executive priority.
daniyal sayyad; Ebrahim Omidvar
Abstract
1-Introduction Runoff is one of the most important components of the hydrologic cycle. Since there are no observational data in basins lacking statistics, the process of calibration and validation of hydrologic models seems impossible in these basins. On the other hand, predicting runoffs in basins lacking ...
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1-Introduction Runoff is one of the most important components of the hydrologic cycle. Since there are no observational data in basins lacking statistics, the process of calibration and validation of hydrologic models seems impossible in these basins. On the other hand, predicting runoffs in basins lacking statistics is essential for planning and management of the basin (runoff estimation, ecosystem services, flood control) (Beck et al., 2016). However, predicting the runoff in basins lacking statistics has been comprehensively discussed using the calibrated hydrologic model in basins having observational statistics through the zoning approach (Yang et al., 2019:67). The zoning approach has been identified as the cheapest and most prevalent solution for solving the prediction problem of flows in basins lacking statistics (Cislaghi et al., 2020:348). According to the definition of the zoning approach, predicting runoff in basins lacking statistics is done using data transfer from basins having statistics to the basins lacking statistics (Rojas et al., 2016). 2- Methodology To conduct this study, firstly SWAT model was calibrated and validated in the watershed basin having statistics; then, the calibrated parameters were transferred to Sukcham basin which lacked statistics, to simulate and analyze the flow using hydro office-FDC software. To analyze the sensitivity of parameters in the zoning approach and for simplifying the complex structure of hydrologic models like SWAT, minimizing the number of parameters in the modeling phases was a necessity. To this end, firstly, a sensitivity analysis was done for the basin having statistics using 14 sensitivity parameters affecting the flow. According to the global sensitivity analysis, the parameters were ranked in SWAT CUP-SUFI-2 based on the sensitivity level and considering two P-value and T-stat factors. Later, 14 parameters having high sensitivity in the basin having statistics were calibrated and transferred to the basin lacking statistics (Sukcham) using zoning and physical approaches. 3-Results and Discussion According to the obtained results from sensitivity analysis of 14 sensitive parameters in the flow simulation, SLSOIL, HRU-SLP, CH-S1, CANMX, SOL-AWC parameters were recognized as the most sensitive parameters of the region. The performance evaluation criteria of NSE, R2, and PBIAS models, respectively, for the calibration periods, were 0.6, 0.65, and 10.7 and for the validation, periods were 0.47, 0.63, and 11.88, showing the acceptable accuracy of daily discharge simulation in the daily scale. After calibration and validation of SWAT model in the basin having statistics and the basin lacking statistics (Sukcham), the daily time step was applied for the 2008-2015 period, and the calibrated parameters of the basin having statistics were transferred to the basin lacking statistics through zoning approach and using physical characteristics. Considering Table (9), the average daily outlet runoff, as well as the average volume of annual outlet runoff for the basin lacking statistics (Sukcham), were estimated. The estimation of such information from basins lacking statistics can present managerial views toward controlling the flood and preventing the occurrence of devastative floods as well as providing the required water sources for filling the aquifers and agriculture in dry regions. Considering Figure (9), the moisture indexes (Q10-Q20) were respectively 0.12 and 0.16 m2/s (10 and 20 percent of the days in a year (33 and 73 days)), discharges were 0.12 and 0.16 m2/s or more. Considering the average extracted index from the curve, flow duration was obtained, respectively, 0.115 (30% of days in a year (110 days)), 0.111 (40% of days in a year (146 days)), 0.094 (50% of days in a year (183 days)), 0.081(60% of days in a year (219 days)) m2/s. Moreover, the scope of low flow index (Q70 toQ95) for 256 and 347 days of a year was obtained 0.058 and 0.024, respectively. In addition, the flood index (Q5) was 0.28 m2/s (5% of days in a year (18 days)), for which the flood discharge equaled 0.28 or more. 4-Conclusions Considering the performance evaluation criteria, the performance of SWAT in dry basins having statistics was good and satisfactory in the daily scale of calibration and validation phase. According to the results of administering the SWAT model in the basin lacking Sukcham statistics, the average daily runoff flow (0.107 m2/s) and the average volume of total annual outlet runoff (million m2) of this basin have been estimated. Then, the flow duration curve was drawn for the Sukcham River in the hydro office-FDC software. Considering the results of the flow duration curve of the Sukcham River, it could be concluded that the scope of moisture, moderate and low flow indexes were respectively, (0.12-0.16), (0.081-0.115), and (0.024-0.058) m2/s. Moreover, the flood index (Q5) was obtained 0.28 m2/s for Sukcham River; which meant that regarding 5 % of the days in a year (18 days), the flood discharge equaled 0.28 m2/s or more. The extraction of these results may help in better recognition of hydrologic behavior of basins lacking statistics for planning and management purposes of water sources such as controlling sudden floods and providing drinkable water and agriculture.
Sayed Meysam Davoudi; Reza Ghazavi
Abstract
1- Introduction The strategic management and planning is the highest level of management that has a long-term attitude in resource allocation and decision making. Relying on a combination of perspectives, policies, structures, and effective systems in this field, the strategic approach in water resources ...
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1- Introduction The strategic management and planning is the highest level of management that has a long-term attitude in resource allocation and decision making. Relying on a combination of perspectives, policies, structures, and effective systems in this field, the strategic approach in water resources management prevents sudden future events and crises that will lead to the sustainable development of water resources (Pour Fallah et al., 2009). Determination and development of water resources are one of the important steps in sustainable use of water resources. There are several methods and models for this purpose, each of which contains its own concept and insight and follows specific techniques and instructions. Among the various models, the SWOT matrix, which assesses the system strengths, weaknesses, opportunities, and threats, is more common and well-known (Hill and Vetbrook, 1997). Extraction of a strategy based on the strengths and weaknesses of the internal environment and the opportunities and threats outside the management field provides realistic solutions to the decision maker, and the closeness or distance of the solutions from the sustainable development model - planning (Azarnivand et al., 2013). Although the common use of this model is mainly related to the strategic planning of production and service organizations, its unique features make it possible to use it in the analysis of various issues such as watershed management at extra- organizational levels. More recently, the use of SWOT analysis for water resources management has been proposed in previous research (Petusi et al., 2017; Negar, 2015). 2 -Methodology This study was performed in four main stages, namely identification of internal and external factors, weighting of factors, creation of matrix for the evaluation of internal and external factors, and finally selection of appropriate strategies (Ghazavi, 2019). The formation of SWAT matrix leads to the presentation of four management strategies as follows. • Competitive/Aggressive Strategy (SO): By implementing this strategy, an effort is made to take advantage of external opportunities. • Review/Conservative Strategy (WO): The goal is to take advantage of opportunities in the external environment to improve internal weaknesses. • Diversity Strategy (ST): Reduce the impact of external threats using strengths. • Defensive Strategy (WT): Defensive mode that aims to reduce internal weaknesses and avoid external threats (Sarai and Shamshiri, 2013) 3- Results and discussionAccording to the results of the present study, the total final score of internal factors was 2.98 in the evaluation matrix, which can mean the strength of internal factors. The total final score of external factors was 2.89 in the evaluation matrix, which means that Natanz city has been able to take advantage of the factors that create opportunities or situations, or avoid some of the factors that threaten the city. Based on the results, the best strategic position for Natanz urban watershed is in the offensive range, which focuses on internal strengths and external opportunities. Besides the existing capabilities and potentials in Natanz should be used in managing runoff management. 4- Conclusion In order to provide appropriate strategies and strategies for strategic management of Natanz urban watershed, strengths, weaknesses, opportunities, and threats were studied using the SWOT method. The findings show that Natanz city, despite a low level of the urban basin for various reasons, was not able to make optimal and desirable use of this natural facilities for its development and progress. The existence of impenetrable levels, digging numerous wells to supply water to factories and industries, and the lack of municipal wastewater treatment plants are some of the threats to the region. According to the results, aggressive strategy is the best structural strategy for the Natanz urban watershed.
Reza Ghazavi; Maysam Nadimi; Ebrahim Omidvar; Rasul Imani
Volume 5, Issue 15 , October 2018, , Pages 54-79
Abstract
Abstract
Introduction
Information about river flow change and subsequent changes in water quality characteristics can help to manage and plan water resources. The environmental and socio-economic impacts of river flow changes are very important in an environmental water management. Climate change is an ...
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Abstract
Introduction
Information about river flow change and subsequent changes in water quality characteristics can help to manage and plan water resources. The environmental and socio-economic impacts of river flow changes are very important in an environmental water management. Climate change is an important challenge that should influence different parts of human life on earth such as rivers and lakes. The Evaluation of the impact of climate change phenomenon on the hydrological processes of rivers can decrease the challenges of managers and planners of water resources in the next period. The selection of suitable models is important for evaluation and prediction of the effects of climate changes on rivers and watershed discharge. Several hydrological models were used to evaluate the effects of climate change on a hydrological cycle. The Soil and Water Assessment Tool (SWAT) has been extensively used, mainly by hydrologists for watershed hydrology related subjects, since 1993. SWAT model should include both a forecasting model and weather generating model. This means that the generated weather data of the future should be presented to SWAT model for forecasting future rainfall and temperature. This is a new possibility for future river and watershed hydrology studies. The main aim of this study was to evaluate the effect of the future climate change on river discharge of the Heruchay River in Ardebil using SWAT model.
Methodology
In this study SWAT2009 model was used to in investigate and predict the quantitative changes of the discharge of the Heruchay River. For the period of 2014-2041, the daily rainfall and temperature data were predicted under three scenarios of A2, B1, and A1B, using LARS_WG climate model. The simulated data was used as the entered information of SWAT model and the model was implemented for 2014-2041 period.
SWAT is a river basin scale model that should work on a daily time-step. It was developed to predict the effect of the management decisions and climate change on the water cycle. In this study, SWAT model was used for its ability to simulate and forecast stream flow and evaluate the effect of climate change on river discharge.
A topographical map (Digital Elevation Model), climate data (daily rainfall, Maximum and minimum temperature), and soil and land use maps were prepared using GIS and measured data. As the precipitation is an important key input that influences flow and mass transport of the rivers, 5 rainfall gauging stations and 2 weather stations located in the study watershed were used.
Result and Discussion
The results of this study showed that SWAT model had an acceptable performance for discharge simulation during calibration and validation periods with coefficients of variation of 0.81 and 0.8 respectively for calibration and validation. Based on the results of A2 and B1 scenarios, the flow rate of the study river increased, whereas a decrease in the flow rate was predicated based on the results of the A1B scenario. The results of the climatic model indicated that the pattern of the rainfall should change in the prediction periods as the rainfall decreases in the winter and spring, while it increases in the summer.
Conclusion
This study offered a methodology for flow simulation and forecasting of future discharge via SWAT model. The effects of future climate change on flow quantity were examined. In this study, SWAT model was used to predict the impact of the future climate changes on river discharge. Model evaluation was done via Nash and Sutcliffe (NS), coefficients of determination (R2), P-factor, and R-factor. After model calibration, the predicted data under several climatic scenario were presented to the model. The results showed that the average of discharge will increase based on the A2 and B1 scenarios, while it will decrease under the A1B scenario. Therefore, it can be concluded that SWAT is a suitable model for discharge simulation in semi-arid areas. The results of this study also indicated that the combination of the results of LARS-WG and SWAT model should lead to an acceptable prediction of hydrological behavior of the rivers. It is important to notice that in this study only the effects of climate change on river discharge was evaluated. For a sustainable management strategy, other aspects of the watershed such as population pattern changes, land use change, and industrial development should be considered. The impact of the climate and land use change on water quality and soil erosion should also be investigated in the future studies.
Reza Ghazavi; Majid Ramezani
Volume 4, Issue 12 , December 2017, , Pages 111-129
Abstract
Extend Abstract Introduction Groundwater is one of the most important resources of fresh water in the world, especially in arid and semi-arid areas. In these areas, the demand for groundwater has increased due to the decline of rainfall, population growth, and industrialization, while its quality has ...
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Extend Abstract Introduction Groundwater is one of the most important resources of fresh water in the world, especially in arid and semi-arid areas. In these areas, the demand for groundwater has increased due to the decline of rainfall, population growth, and industrialization, while its quality has declined via industrial and urban contamination. The removal of the groundwater pollution is very costly and time-consuming. Consequently, the prevention of the groundwater contamination is the best way for groundwater protection. The main aim of this study was to investigate the trend of groundwater quality and quantity changes in the Rafsanjan plain in relation to the groundwater discharge and rainfall change. Methodology The study area is the Rafsanjan plain with an area of 5459.36 km2 (with an altitude of 45°, 30¢ to 56°, 30¢ and latitude of 29°, 59¢ to 29°, 15¢). In this study, the essential maps including topography, drainage, piezometric wells location, and groundwater quality and quantity maps were created using GIS10.1. The groundwater level in 80 pizometric wells and the groundwater quality in 50 wells were investigated and analyzed for a period of 10 years (2002-2012). The groundwater unit hydrograph and rainfall pattern were compared to indicate the impacts of rainfall variability and the groundwater over-extraction on the groundwater level variation. Water quality maps were created using Vilcox method. Based on kriging interpolation method, the quantitative and qualitative maps of the study area were prepared using geographic information system (GIS). Results The groundwater hydrograph of the study plain indicated that the groundwater level declined continuously. As during the past 10 years, the groundwater decline was 8 m, so the annual groundwater decline in the study plain was 0.8 m. comparing the groundwater level of 2002 and 2012 via piezometric wells indicated a significant decline of the groundwater level. In 2002, for 81% of the study plain, the groundwater level was between 30-90 m, while it declined to 68% in 2012. The maximum groundwater decline was related to the area where groundwater level in 2002 was between 30 and 60 m. The area where the groundwater level was between 90 to 120 m, it increased from 683.8 km2 in 2002 to 999.7 km2 in 2012. Also the area where groundwater level was more than 120 m, it increased by 5.3%. A significant relationship was observed between the groundwater level and the volume of the groundwater extraction in 10 years of the study (R2 = 0.6). However, no significant relationship was observed between the groundwater level and the average rainfall between 2002 and 2012 (R2 = 0.04). These results indicated that the impact of the groundwater extraction on the groundwater level decline was more important than the rainfall change. In this study, Wilcox method was used for the investigation of the variability of the groundwater quality. Based on Electric conductivity (EC) and Sodium absorption rate (SAR) in Wilcox method, 16 classes of groundwater quality should be investigated. According to these results, in 10 years of the study period, the number of wells located in C3S2 and C4S2 classes of groundwater quality declined by 2 and 4% respectively. The number of wells located in C4S4 increased from 33% in 2002 to 38% in 2012. Cumulative discharge of all study wells decreased from 610 liter per second to 469 liter per second. The maximum decline was related to C4S3 and C4S2 groups. Discussion The results of this study indicated that the groundwater quality and level declined in the study area. According to the results of the water quality maps, the area of the aquifer with groundwater quality located in C3S2 and C4S2 respectively decreased by 6 and 1.4 %, while the area of the aquifer with groundwater quality located in C4S4 increased by 4.5 percent. The study of the piezometric wells with a depth of 30 m and less indicated that 15% of these wells dried between 2002 and 2012 due to groundwater level declination. The water quality of the profound wells (with a depth of 31 to 200m) decreased by 8.5%. These results indicate that the groundwater quality decreases with increasing of the groundwater level. Conclusion According to these results, the groundwater decline due to the rainfall decline, and the role of the groundwater abstraction in the agricultural area were more important than the rainfall deficits. The qualitative and quantitative maps of groundwater were also prepared via kriging interpolation method and GIS. Based on these results, it can be suggested that rainfall decline leads to the decline of groundwater, but excessive removal of groundwater resources in agricultural lands is a major factor that should reduce the quality of the groundwater in the study area.
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 ...
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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 regions with a limited water resources is a serious problem. In this research, the DRASTIC and GODS methods were used to study Rafsanjan plain's potential vulnerability to pollution. To this end, seven layers including groundwater depth, net recharge, aquifer media, soil, topography, and unsaturated zone hydraulic conductivity were produced for the DRASTIC method. In addition, to create potential vulnerability maps using GIS for the GODS method, four layers including type of groundwater, unsaturated zone, water table depth, and soil environment were combined. The degree of the changes of the electrical conductivity of the plains was used for the validation of the models. According to the results, the DRASTIC index is between 61.33 and 183.75 for the region, categorizing Rafsanjan plain to five classes of vulnerabilities including very low 0/54%, low 32/93%, medium 55/40%, high10/54%, and very high 0/59%. The GODS model, in contrast, classifies the region to three classes of vulnerability including low 32/27%, medium 67/04%, and high 0/69%. In both models, the most part of the study area was classified into medium level of vulnerability which were respectively 55.40 and 67.04 in the DRASTIC and the GODS models.
