جستجوی مقالات مرتبط با کلیدواژه « تاب آوری » در نشریات گروه « آب و خاک »

The concept of resilience is particularly important in water distribution networks, which are important urban infrastructures. Estimating and evaluating resilience in each network at the time of design will reduce damage to subscribers and the network. In this research, relationships and functions related to resilience (GRA) in water supply systems and solutions for how to increase resilience using two scenarios of pipe failure and additional needs for the Kangavar network were investigated and implemented.

By modeling the initial failure modes by increasing the stress intensity and estimating the consequences that arise, the resilience of a system can be evaluated, which includes the following steps (Diao & et al. 2016):Step 1. Identify the failure mode to evaluate (eg structural failure, excessive demand).Step 2. Determining the system stress associated with the failure mode and its simulation method (for example, WDS simulation with an additional load on a node for a certain period).Step 3. Identify the appropriate system and how to measure it (eg ratio of unsatisfied demand to total required demand during the failure period).Step 4: Simulate the consequences of the failure mode at increasing stress intensity (0%-100% of maximum stress). While stress intensities up to 100% may be highly undesirable, they are theoretically possible and should be considered if a wide range of potential effects are identified. For each given stress value, the appropriate number of failure scenarios is determined.Step 5. Create a stress-resilience curve that shows the average, maximum, and minimum results produced by the simulation for each given stress value.

The worst situation for Kangavar network starts at 89% failure and remains until 100% pipe failure. In large networks like the Kangavar network, the graph of the strain duration and the stress duration have a steep slope just like the supply shortage graph. For example, for the value of five percent pipe failure, all three values of minimum, average and maximum strain duration are equal to five. That is, when only five percent of Kangavar's pipes fail, the duration of the strain reaches its maximum.Among the prevention ways to reduce the lack of supply in case of pipe failure, adding parallel pipes for pipes with a more important position compared to other pipes or looping the network in different areas of the network. For the Kangavar network, 38 pipes were added to the network. These pipes are mostly parallel to the pipes coming out of the tank. After adding only 38 pipes to the network, the amount of supply shortfall is greatly reduced.The state of excess demand is actually a state in which a number of certain nodes have a need or demand more than their defined capacity in a certain period of time. This situation is actually very similar to when a fire occurs in the network, except that in the case of a fire, the normal and usual demand of the network may decrease a little. But in this simulation, in addition to the normal need and demand, additional needs are also considered.Figure 12 shows the duration of the fire for hours 18 to 21. In this period of time, in the worst case, i.e. in 100% of the nodes with higher demand, the network faces only 10.82% supply shortage. This means that if all eleven selected points in the network have additional needs at the same time, the network will have an approximately 11% supply shortage. In this situation, it can be seen that the stress applied to the network occurs at the same moment and the duration of the strain is six hours.

The results showed that the duration of the strain increased with the increase in the percentage of pipe failure. But the graph related to the start of strain had a downward trend and approached zero with the increase in the percentage of pipe failure. The level of resilience for a network is different in different scenarios, in fact it is possible in with equal failure percentage, and the network has more resilience in one scenario than in another scenario. With a slight increase in the percentage of pipe failure in some water supply networks, the amount of strain increases greatly. While in other networks, even with a large increase in failure percentage, the size of the slope strain has started to increase slightly. One of the most important reasons for this depends on the type of network design. For example, if the water supply network is defined as a loop, in case of failure of one of the pipes, part of the lack of demand will be supplied by other pipes. Adding new pipes to the network was one of the solutions considered to increase the resilience of the network in this research.

Flood governance and risk management involve measures and strategies aimed at reducing the risk of floods and managing their impacts. This process includes identifying and evaluating risks, planning and prevention, readiness for response and performance in crisis situations, effective and rapid response to floods, and constructive measures and continuous improvement. The main approach of this research is based on five themes related to various issues related to flood risk management, which include stakeholder engagement, policies and action, research on practice, supporting tools, governance, and frameworks. The study of flood risk management has experienced significant developments over the past two decades. Attention to the application of flood risk management and comparative analysis of flood governance in flood management studies has been undertaken, which means creating a complex arrangement that shapes the behavior of governance and social actors regarding flood risk management. Based on the results of the review of research sources, the main structures of flood risk management and flood governance studies are strongly interrelated but also differ in their main structures, which are evident in the discovered keywords in the analysis. The articles were codified based on the main topics in MAXQDA software, and then the complete sets of codes in all reviewed articles were examined. The findings of the research show that improving flood resilience requires extensive efforts in the fields of physical and social sciences. Researchers should, for flood forecasting and modeling, in addition to the physical sciences, develop social science tools. These actions can help improve the planning and management of flood crises and reduce their social and economic effects.

Flooding in urban areas is increasing due to population growth with improper land use planning and climate change-induced increase in extreme rainfall events. Flood risks have affected the largest proportion of the world's population (45%) compared to other natural disasters and caused 5424 recorded deaths between 2000 and 2017, and if our cities are to be resilient and better able to deal with the consequences of floods. city to cope, it is expected that they will adopt sustainable strategies to adapt to the new climatic and socio-economic conditions. Accordingly, the purpose of this research is to evaluate the resilience of Shiraz city against floods in order to identify areas of low resilience and take the necessary measures to increase it. Their resilience should be done.

The research method of this research is descriptive-analytical and practical in terms of purpose. Based on the background of the research and refinement of the variables based on the conditions of the research area, four dimensions and 24 criteria were determined, including demographic (8 variables), economic (3 variables), environmental (4 variables) and infrastructure (9 variables).

AHP method was used for weighting and access to critical infrastructure for action and recovery has the highest weight with a weight of 0.115, and infrastructure with a weight of 0.395 has the highest weight. The estimated CR of the model is equal to 0.07, which it shows the acceptable accuracy of the model. For zoning, the Vikor model has been used, and based on the output of the model, 9.92% of the area is in the zone with low resilience, where about 16.63% of the population of Shiraz lives in this zone, and about 75.43% of the area is in the zone with medium resilience. 74.56% of the population lives in it, and the area with high resilience is 14.65%, where 8.81% of the population of Shiraz lives.

Iran is located in an arid and semi-arid region, where a large part of its water needs is provided by groundwater resources. In severe and prolonged periods of drought when it is not possible to supply water from surface water resources; Groundwater will be the only source of water supply. Not paying attention to demand management and not controlling over-harvesting during the drought period can further reduce the groundwater storage. Preventive strategies are necessary to reduce the effects of drought and protect groundwater. But unfortunately, most of the strategies to reduce the destructive effects of drought are passive (or reactive) and seek to supply water shortages from groundwater resources during the drought period, and attention to the active strategies of combined groundwater-drought management has been neglected. Therefore, due to the increase of severe and long-term droughts under climate change, it is necessary to pay attention to active strategies and new approaches. Demand management and harvesting reduction as a proactive approach can reserve groundwater in normal and wet years and increase drought resistance by preserving underground resources and ensure water supply security during severe droughts. This article is compiled in two parts in order to explain this approach. The first part describes the planning of related organizations for the combined management of drought and groundwater, and in the second part, the new approaches implemented in California as well as its application in Iran are explained.

The inadequacy of water resources to meet the needs of food production is a very important issue that will increase in importance in the future. If local renewable water sources (in soil) and water (in rivers, lakes, reservoirs, aquifers) are sufficient to produce a reference food supply (including 3000 kcal of daily requirement, of which animal products include 20 percent) for all residents. If not, we consider a food production unit to have a lack of green-blue water. If it is not enough for all residents, we consider a food production unit to have a lack of green-blue water. The number of people living in food production units affected by green-blue water scarcity has increased from 360 million people in 1905 (21% of the world's population at that time) to 2.2 billion (34%) in 2005. During this period, the lack of green-blue water has spread to large areas and has increased in previous areas. Water security is a concept that is examined in different dimensions and aspects. Four dimensions of these cases were identified, each of which consists of two complementary aspects: direct-indirect, macro-micro, technical-political and peace-conflict. In this study, the indirect role of water on food security on a global scale was investigated using a quantitative spatial approach. Since food security is intertwined with water security in many ways, the role of water scarcity on the disruption of food production and the impact of trade on this interaction was analyzed, and while examining the relationship of social resilience with these issues, the areas that It was identified that they were facing certain challenges in this field. With this work, the concept of water security became systematic and finally related to the issues of vulnerability, resilience and sustainability.

Resilience is recognized as a potential capacity of a community at risk that faces hazards for adaptation or resistance to change to achieve or maintain an appropriate level of performance. Occurring environmental changes, rural areas are affected more and more vulnerable. Considering the importance of resilience in understanding the syntax of dealing with critical issues, this study examines the role of livelihoods diversity in resilience and welfare of the rural community in facing climate change using the factor analysis method with 5 indicators and 38 sub-indices in 2019-2020. In this study, 206 questionnaires were completed in the village of Jaro in Alborz province. To achieve the research goal, using Cronbach's alpha was first used to ensure the reliability of the questionnaire. The results show that 38 factors are questioned in eight groups. In the first group (the most important group), many indicators such as participation in collective employment activities, familiarity with new market needs, business development through the use of new technologies, business development through the use of new technologies, experience in a variety of occupational environments, learning new skills in economic activities reflect the importance of recognizing the basic needs of the market and increasing the ability of villagers to carry out alternative agricultural activities in crisis.

Resilience is a criterion for measuring the strength and stability of a system and its ability to absorb changes and distribute them, while at the same time maintain relationships between system variables. The ability of societies to live and develop with dynamic environments is known as ecological resilience. When the accessibility of a vital resource (such as water) varies between overabundance and extreme scarcity due to natural or man-made phenomena, management should be flexible and the authorities adapted with maintaining legitimacy. So, the prediction of ecological resilience in water resources such as rivers is an important issue that needs to be considered for better management of land-use systems and water supplies. For this purpose physical and chemical parameters in rivers should be monitored to predict and understand the behavior, flexibility and interaction between living-beings of rivers. The ecological importance and reorganization features of algae, as well as being directly influenced by chemical and physical parameters make them eligible to be considered as indicators of nutrient pollution and to be the endpoints for numeric nutrient criteria developed for water quality management aims. But, most environmental models do not address water quality in relation to river biology over time and offer little prediction for future periods. Time series modeling and forecasting have importance in various applied studies, such as resilience in which resistance to chronic stress and time series are to be significant. In spite of various studies on intelligent modeling in the field of water management, no study has yet investigated the environmental resilience of the river in Iran, using the time series and artificial intelligence models. The resilience indicators examined for rivers have included four criteria: the biology, impact of pollutants, climate change, and time. The mentioned criteria were investigated in accordance with the following factors: Diatom algae, chemical parameters, discharge variations, and 10-year time series. The input data for modeling relations in the river ecosystem for Diatom were based on the factors influencing the physical and chemical parameters of these algae (EPA2017), and also on the basis of statistical methods of their correlation coefficients. Resilience index in the current study was determined based on Diatoms population with regard to Diatomic-Trophic index. In this respect, this study proposes a gene expression programming (GEP), hybrid wavelet-gene expression programming (WGEP), support vector machine (SVM) and wavelet support vector machine (WSVM) for prediction of monthly variations in Lavarak Station’s water quality that affect bio indicators. The 10-years (2002-2012) monthly data used in this study were measured from Aliabad River located in Tehran, Iran. First, the measured discharge (Q) and other quality parameters that affect the bio indicators data sets were initially decomposed into several sub-series, using discrete wavelet transform (DWT). Then, this new sub-series was imposed on the (GEP) and (SVM) models as input patterns to predict monthly bio indicator one month ahead. The results of the new proposed WGEP and WSVM models were compared with SVM and GEP models. The performance of this model was evaluated using Nash-Sutcliffe efficiency (NS), root mean square error (RMSE), and mean absolute error (MAE). A comparison between the four models showed the superiority of the hybrid models over the classic models. The achieved results even pointed to the superiority of a single SVM model over the GEP model. With regard to the studies conducted to determine the bio - resiliency index, the abundance of Diatom algae in the river within the standard of resilience the WSVM hybrid model was better while the WGEP was the second best. But due to the modeling process and the results, the WGEP model was used to determine the formula and the effect of each parameter was defined in the scenario. This model can also be effective in expressing changes in one or more independent parameter. The results of this study indicated that considering the capacity and the ability of AI models to deal with the nonlinear nature and dynamics of hydrological processes, the ability of wavelet analysis to extract certain periods of a time series is potentially more to gain reasonable prediction in different environmental processes and planning for them.

The pressure on ecosystem and the reduction of welfare and livelihood in human communities are one of the most important effects of drought which, if the severity and duration of this event increases, could become one of the most catastrophic natural disasters. Therefore, many countries have different climate-based policies in facing water stress issue, such as severe and prolonged droughts. However in almost all of them, groundwater has been considered as a strategic resource because of its reliability in water stress situations. Strategic groundwater resource refers to the volume of fresh groundwater that should be stored in an aquifer for various activities, especially for drinking water, and also to be gradually used for human needs in some serious long-term droughts. Strategic groundwater reserve is the most important support of water supply management in water stress conditions of "severe and prolonged droughts" particularly in arid and semi-arid areas. Unfortunately for many years, the concept of balancing water resources and developing sustainability has received little attention in Iran, consequently this unique water resource is continuously declining. This study sought the necessity of developing the concept of Probable Maximum Drought (PMD) as the basis for determining the maximum withdrawal of groundwater, as the most important factor for increasing resilient development in water stress conditions by preserving strategic groundwater reserves. The lack of attention to maintaining strategic resources could bring irreparable damage and cause changes in society. Finally, this study introduces suggestions for drought risk management based on the aforementioned concept hence, it is important to develop a comprehensive program for drought risk management in the event of severe and long-term droughts for each study area.