Performance Assessment of Storm Water Drainage Systems (Case study of Debere Berehan Town)
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Date
2018-12-10
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Publisher
Addis Ababa University
Abstract
A drainage system degrades by multiple factors and its performance reduces in time. Since such
infrastructure play a key role in preventing urban floods, their performance should be monitored
and quantified. Debere Berehan town is one of the rapidly expanding and selected as factories
center now a day in Ethiopia. Unfortunately, street flooding and over topping drainage system
problems are occurring at the rainy season in a town. Because of flooding the area are becomes
water soaked soil which difficult to move easily for Transport. The objective of the study is to
assess the Performance of drainage systems of Debere Berhan Town. The study employed both
primary and secondary data collection. To achieve the specific objective SWMM5 Model and
LID control used as method. Model calibration and validation were done and The performance
of SWMM5 was carried out using Coefficient of Determination (R
Performance Assessment Of Storm Water Drainage Systems
(Debere Berehan Town Case Study) Page ii
2
) ,The Nash-Sutcliffe
coefficient (NSE) and Relative Error (RE).According to simulation almost all of the modeled
drainage systems are flooded for each event scenario rain. For T-25 event 35% of closed
rectangular channel and 32.5% of Open rectangular channel of the Study area were flooded.
More over the total average flow1.64 m
3
/s and total volume to outfall 87.75*10
3
m
3
were
occurred from all 17 sub catchments. After LID control provided the discharge values were
lesser than that before LID provided. In comparison to the current conditions, bio-retension
reduced total outfall volume by 46.2% and average peak flow by 25.4%, the infiltration trench
scenario as well reducing total volume to outfall 34.4% and average peak flow by 23.7% as
compared to current conditions. In general, the LID results shows bio-retension are best
alternative to minimize the peak flow rate and total volume of the area. And applied to the
selected area 3.6 ha at S8, S9, S10, S11, S13, S14, S15, S16 and S17 catchments were
recommended.
Description
Keywords
urban drainage, SWMM5, model calibration and verification, LID control