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Historical Flood in. Incheon Gyo Watershed. Online Collaboration. Web Platform Web Platform was used as part of the communication media and storage of documentation. MSN and Adobe Connect. Remote Desktop for available technical software. About Incheon.
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Historical Flood in Incheon Gyo Watershed
Online Collaboration Web Platform Web Platform was used as part of the communication media and storage of documentation. MSN and Adobe Connect. Remote Desktop for available technical software.
About Incheon Located in the mid- west Korea peninsula near Yellow Sea 37° 29 N, 126° 38 E 3rd biggest city in Korea Area: 1002.7 km2 Gateway of North East Asia Facilitated with both international airport and port.
Gaja WWTP Pump Station Juan station Gansuk station Study area City Hall Project Overview 1. Incheon Gyo Total area: 34㎞2 Elevation: 0 ~ 201m(EL+) Average of slope: 0.01% Reclamation land. Tidal difference of Yellow sea which is linked with Incheon Gyo watershed is 9m. Concentration of rainfall is usually in August.
Project Overview 2. Flooding Occurrence Occurred at coastal area located at the downstream of drainage system. despite the heavy rainfall return period of 2-3 years. Max. rainfall (1997-present) In 1997: 260.8mm/day 3. Impact • Direct: • buildings and houses destroyed • quality of life decrease • profit losses • costly repair and management. • Indirect: country’s economy and security.
Simulation Process Solution analysis (output) Preparation (input) Tools (software) Geography Hydrology DHI ISIS Sobek Results format: video; figure; table… Analysis: Physical meaning & comparing with observed data • Catchments • Building • Manholes • Road • Rainfall intensity • Duration • Time interval • Storm return period Mike Flood Retry Mike 21 Mouse Mike Zero Suggestion
Hydrology Analysis • Precipitation data • Design Precipitation • Observed Real Precipitation • Runoff Coefficient • Total Runoff Coefficient • Sub-catchments Runoff Coefficient
mm/hr mm/hr Precipitation DataDesign Precipitation • Suggested probability rainfall intensity formula in Incheon
Precipitation DataDesign Precipitation Intensity-Duration-Frequency curvesfor Incheon-Gyo area
Precipitation DataDesign Precipitation Design precipitation hyetographs from IDF relationships
ArcGIS • GIS files: • Catchment • Manholes • Building • Road • Contour • GIS files were used to create TIN, DEM, and also others, being converted to ASCII files to produce necessary input for MIKE (Simulation) + Simulation (MIKE)
DHI MIKEIntroduction • To analyze the flooding problem we try to obtain a real approach of rain impact on Incheon Gyo catchment. • We have simulated the general Incheon Gyo characteristic with the MIKE software. • It is easy and efficient to report the realistic aspect of the flooding reality with DHI software
DHI MIKEIntroduction • There are several processes to simulate the flood. • To simulate the flood imputation of the sewer network (Mouse) and the DEM (MIKE 21) must be connected to observe the catchment behavior. • It is necessary to couple with MIKE21 MIKE FLOOD
DHI MIKEProcess Flowchart MIKE ZERO MIKE 21 MOUSE Bathymetry Simulating the surface flow Simulating the sewer network flow MIKE FLOOD Coupling MOUSE with MIKE21
Bathymetry • Bathymetry file from MIKE Zero to MIKE 21
Simulating the surface flow DHI MIKEProcess Flowchart Bathymetry Boundaries conditions MIKE 21 Simulation period
Simulating the surface flow DHI MIKEPart Concept • Removed the bad node to obtain good result from the simulation (conflict between bad node and building altitude) Sewer Network Simulation Period Rainfall Data & Water Level Boundaries Conditions Mouse
DHI MIKEPart Process • We can calculate the water level and flooding and the real reaction of the sewer network. • With retention pond, • Downstream water level : 4,64 m, • Reference rainfall intensity = 1997/08/04 Time = 24 hours H= 207,6 mm
DHI MIKEPart Process After the first simulation containing the 6 extremes rainfall value of 1997 : • Research of the principal nodes of junction where there are some flood problems. • Creation of under reservoirs in these nodes junction to reduce the rain impact on the sewer network (330 m3 each under reservoir)
Proposed SolutionBuried Retention System • Integrated reservoir to get the water out. Bottom Inlet discharge Outlet discharge Storage water 330 m3 1.1m
Retention System Without Storage Basin Discharge: 25.503/ 24.795/ 26.082 With Storage Basin Discharge: 26.748/ 25.888/ 26.944
Attempt on Other SoftwareHalcrow ISIS • Initial idea of using another software for validation of simulation. • However, due to time constraint focus was given to 1 software (MOUSE)