negin binesh

Sustainable management of Urban Drainage Systems (UDSs) is challenging since the hydraulic characteristics and pollutants discharged into catchment areas are constantly changing. Quantifying the resilience of UDSs is a crucial step towards long-term and sustainable management of these chatments in urban areas. This study was performed to evaluate the resilience of UDSs against flooding through combining hydraulic performance of stormwater drainage network with the system performance function. To conduct this performance evaluation extreme rainfall intensity values for different return year periods ranging from 2 to 100 years were used for catchment drained into the West Flood-Diversion (WFD) system in Tehran. Both hydraulic and hydrodynamic simulations were performed for these stormwater drainage system under two scenarios: with and without BMPs. To further evaluate the systems performance and resilience, additional simulation analysis was performed using one specific flooded node under extreme rainfalls with different return periods. The results showed that adding a vegetative swale to the drainage system would decrease the nodal flooding duration and the flood volume up to 15% and 47%, respectively. The results also shown that the resilience against flooding will increase from about 0.4% up to 6% under the above-mentioned conditions. From the results of this study, we can conclude that employing some types of BMP along with the existence low-impact development measures within the traditional urban drainage areas may be sufficient to increase the system resilience and sustainable control of flooding.

Urbanization has been one of the challenges of the present century that have consequence including its effects on reducing the amount of surface runoff to the ground and the occurrence of urban floods. Contamination of these runoffs to variety of elements in urban environments is also a problem that with low levels of surface runoff which makes it difficult to direct applied them for other purposes. Today, one of the best ways to reduce the volume and pollution of surface runoff is the use of best management practices (BMPs) that have been the focus of most cities around the world. In the present paper, the effects of some of these strategies, including garden-canal and permeable pavement, on reducing runoff contamination in the study area, which is part of Tehran Municipality 10, It has been studied using surface runoff management software. Different scenarios have been considered for using these management strategies. In all cases, the results show that the efficiency and effectiveness of using these two types of BMPs have been in reducing the volume and peak runoff and runoff contamination. The results showed that the permeable pavement had a better performance in reducing the peak and elimination of pollution in the studied area and the best option in most scenarios was the combination of garden-canal and permeable pavement practices.

The impacts of climate Change, more than being influenced by the change in precipitation amount, is affected by the changes imposed by this phenomenon on rainfall regime (intensity and frequency); it means that climate change can cause extensive droughts/floods due to impact on temporal and spatial rainfall distribution, and hence, conducting some studies on return period of extreme rainfalls seems to be necessary. Current paper investigates and analyzes the effect of climate change on extreme regime in WFD catchment at three time horizons (2036, 2060, and 2090) under A1B, A2, and B1 emission scenarios. Investigations (performed by the authors during previous researches) show that the most accurate which is capable of simulating the trend of precipitation variations in the studies catchment, would be MRI-CGCM3 Downscaling was performed using Change Factor (CF) method. The results are representative of reduction in rainfall amount in future time periods, So that the predicted rainfall reduce between 4.12 to 11.69 percent compared to observed baseline precipitation. In addition the result of extreme rainfall analysis show that by moving towards the distant future, the amount of annual extreme rainfalls decrease for a specific return period. However intensity and return period of a specific extreme rainfall increases significantly and therefore, applying adaptive measures for urban flood prevention in the catchment appears to be necessary.Also the probability of extreme rainfall occurrence with a given value in distant future is greater than near future.

The two factors of the trend of climate change and urban development pose a challenge to urban drainage infrastructures due to the adverse impacts on precipitation extremes and urban environment. Nowadays, Sustainable Urban Drainage Systems (SUDS) have become quite popular as a result of their positive effects on the water quality, quantity, amenity, and recreational affairs in urban landscapes. Today, the majority of the world agrees that a sustainable drainage approach has an influence in reducing global climate change and adapting to this phenomenon (which has already started). The current paper reviews recent progress in the development of sustainable drainage, based on interdisciplinary studies. First, the reasons behind moving towards a sustainable urban drainage system are mentioned and then, existing models and decision-aid tools to assess different types of SUDS are compared and discussed. This paper also explains some limitations and challenges related to applying SUDS in practice and finally, the results and conclusions are presented.

In open channels, the distribution of velocity, shear stress and other related quantities such as the diffusion and dispersion coefficients and thus all transport processes are three-dimensional, according to the three-dimensional convection and diffusion principles. Determining the velocity distribution- as a key parameter for estimating other hydraulic parameters- has always been the subject of attention. Velocity distribution in the inner region of the flow (y0.2D). The log-Wake law is of the most accepted laws for velocity distribution in wide open channels, this law modifies the logarithmic law by adding a Wake function; but in case of narrow open channels, the log-Wake law deviates from the measured data near the free surface. Because the profile by the log-Wake law depicts the velocity which increases with the increase of distance from the bed monotonically and is not able to show the velocity negative gradient near the free surface which happens in narrow open channels. In narrow open channels, the three dimensional structure of the flow and the transport momentum from the side walls to the central zone due to strong secondary currents, causes the maximum velocity to occur below the water surface which is called velocity-dip phenomenon. The velocity dip phenomenon was first reported more than a century ago. Since that time, numerous investigations have been conducted by many researchers in order to propose new models to be able to not only describe the dip phenomenon and negative gradient of velocity near the free surface, but also to predict the position of the maximum velocity accurately and fit the experimental data throughout the whole flow depth.
This paper introduces an analytical model based on Reynolds Averaged Navier Stokes (RANS) equations and an eddy viscosity distribution, to estimate velocity distribution in turbulent fully developed flows. The proposed model is suitable for both narrow and wide open channels, and is capable of predicting the dip phenomenon. The results by the model verified with data measured in several rectangular lab channels and data collected from an actual sewer channel. Since the proposed equation for velocity distribution is dependent of Coles Wake parameter (Π), the effect of this parameter on level of accuracy and description of velocity profile as well as prediction of dip phenomenon and location of maximum velocity has been studied. Many researchers proposed different values for Coles parameter, and it seems there is no universal constant value for this parameter. In this study, the value of Coles parameter was proposed by fitting the data from different channels, based on the least error calculated in predicting the velocity profiles by the proposed model. The results show that the profiles by the model agree well with experimental data and predict the velocity-dip phenomenon; also the model provides little errors compared to measured data in the channels, which is representative of high level of accuracy in defining velocity distribution profile of the flow. The value of Coles parameter estimated for channel-sewer was less than that for lab channels.

Rainfall and flow rate are of the most important climatic and hydrologic parameters whose investigation and determination of their behavior are of great importance in water resources management. One of the most suitable methods available for assessment of hydro-climatological conditions in the watershed is trend analysis which is used to examine the changes of a variable during time. Current study has been implemented in two parts. The first part of the study investigates the effect of rainfall changes on Darakeh river flow rate between 1989- 2012. To do this, monthly recorded data of rainfall from Haft Howz station (on Darakeh river) and methods such as graphical Mann-Kendall and linear regression tests were used. In addition, rainfall and river discharge anomalies were examined during the 24-year period. The results indicates that rainfall time series in Darakeh watershed has a positive and rising trend, though this trend is not significant. Also river flow rate increases with a slight slope during the studied time period and doesn’t show a significant trend. Totally it can be concluded that except for some particular time periods, increase and decrease in the amount of rainfall and river flow rate has not been concordant. The second part predicts the future rainfall in the catchment using MRI-CGCM2.3.2a under A1B emission scenario for three time horizons (2030, 2060, and 2090). The overall results are representative of reduction in rainfall in Darake river basin in the future.

Health Centers, as the most involved organizations at the time of occurrence disasters, need to be considered more important than other parts of society from functional, structural and non-structural viewpoints. The objective of this research is identification of internal and external factors that affect non-structural and functional vulnerabilities of Imam Khomeini Hospital in Songhor township (Kermanshah province), and ranking them in order to determine the best strategy for reducing vulnerability against earthquake.
This is a descriptive-analytical survey research which applies AHP-SWOT hybrid method. First internal factors (strengths and weaknesses) and external ones (opportunities and threats) were recognized by using SWOT model, and then these factors were weighted and ranked through applying AHP method in order for the best strategy to be find. Data gathered through literature review, observation, interview with the staff and applying questionnaire among the personnel.
Findings: According to the findings of this survey and the questionnaires distributed among the personnel in different sections of the hospital, several factors including warning system, drills, temporary housing facilities, staff training, and emergency evacuation were determined as the most important factors related to reducing vulnerabilities of the Hospital. About 95% of the respondents believed that an appropriate and effective warning system is necessary for hospital. 20% of the staff stated that lack of training for personnel for acting properly at the time of occurrence of earthquake, is the weak point of this hospital; while others mentioned problems related to “emergency evacuation in critical conditions” as the weak point.
Data analysis and prioritizing defined criteria related to seismic vulnerability of the said hospital demonstrated that external opportunities and internal weak points gained the highest score among the main four factors. Finally WO strategy (with a final score of 0.39) ranked first and was chosen as the best strategy; which means that through utilization of available external opportunities, internal weak points will be eliminated or reduced. In this way, seismic vulnerability of the hospital will be reduced as well.