تأثير تغير المناخي على تشغيل شبكات مياه الامطار: دراسة الحالة في مدينه كربلاء

CLIMATE CHANGE EFFECT ON OPERATION OF STORM WATER NETWORKS A CASE STUDY IN KARBALA CITY

The flooding of a storm water network may caused by climate change, land-use change, increase in urbanization, and the wider population. Therefore, this study deals with the development of computer model to extrapolate future change in rainfall events in order to protect the infrastructure of the storm water network from flooding. For the current study, the Al-Abbas quarter in Karbala city, Iraq was chosen as a case study. The historical data for the period of 1980-2016 was utilized to predicted rainfall intensity for future period 2017-2070 and study the effect of climate change on such prediction. The artificial neural network ANN model was used to analyze the data. The input layers that enter to ANN model include climate change parameter such as monthly rainfall, minimum and maximum temperature, wind speed, humidity, and sunshine. These data were divided in two groups: the first group 95% of the data and represent the training data, while the second represent the test data 15% of the data and used for calibration. Output parameter includes rainfall intensity. Following this, a Storm Water Management Model (SWMM) model is constructed in order to assess the flood conditions of the study area for expected rainfall intensities. The results indicate that the maximum rainfall intensity will reach 46.48 mm/h. in 2067. This value represents three times of the design intensity. The percent of the flooding manhole increase with the progress of time. Five design stages were selected for each specific time period during the design period of the study which was 53 years to show the variance in the flooding of manholes. It’s an example, the flooding rate during the first stage decrease by 39.2% in 2070 while in the second stage the rate increase by14.2%, the third stage increasing in 6 time, the fourth stage has no change, and fifth stage increase with a rate about 6% compared to the beginning period (2017).