| dc.description.abstract |
The challenges that managers and urban planners have long observed are preventing
urban flooding, and failure of drainage structures. Only stormwater drainage systems
hydraulically with high reliability can accomplish this. The objective of this study was to
evaluate the hydraulic performance of the existing stormwater drainage systems in Woreta
Town. Maximum annual rainfall data from 1987 to 2016 were used. The intensity duration
frequency curves of the study area was developed using the Log-person type III. The
physical parameters of the sub-catchments, especially the terrain of the catchments of the
study area, were examined using Google Earth and ArcGIS. The SCS TR-20 method was
utilized in HydroCAD to determine the culvert catchment peak discharge. The analysis of
the culvert flow overtopping was performed using HY-8. The maximum channel flow rate,
maximum velocity, and maximum water level were assessed using a stormwater
management model. The 213-hectare region was chosen for the SWMM area because it
has drainage problems and has historically been prone to flooding. 42 sub-catchments
make up the model's area, and its drainage system consists of 56 conduits, 57 junctions,
and 7 outfalls. The two most sensitive parameters N-pervious and N-impervious were
calibrated using ten channel flow depth observations in 2021 until the simulated and
observed flow depth values reached an acceptable threshold, and seven events in 2022 to
verify the model. The SWMM model performs best at C21 (R
2
=0.95, d=0.97, and NSE
=0.84), C36 (R
2
=0.93, d=0.96, and NSE =0.85), and C21 (R
2
=0.79, d=0.94, and NSE
=0.78), and C36 (R
2
=0.71, d=0.82, and NSE =0.58), respectively, in terms of calibration
and validation. According to the SWMM finding, the research area has poor freeboard
performance on several channels. But there is high velocity performance on almost all
channels except C39. The weighted System reliability is 68%. This shows that while the all
over system's performance is acceptable, it is not exceptional. The HY-8 model's findings
show that culverts 1 and 3 have overtopping problems. This study suggests redesigning
road culverts that have issues with overtopping and storm drainage to meet the minimum
freeboard standard.
Key Words: HydroCAD, HY-8, SWMM, Reliability |
en_US |