UKWIR/FRMRC Integrated Urban Drainage

Model application in Torquay with 1D & 2D surface flow modelling

21st October 2009

Overview

Study Objectives Background Data Modelling 1D Modelling 1D/1D Modelling Imperial College 2D Modelling - Infoworks

Results Conclusions

Study Objectives

To apply and evaluate the new 1D surface flow model developed bythe FRMRC to support the better management of urban flooding. Application will be within a sub-catchment of Torquay, Devon as agreed with the Project Steering Group using selection criteria prepared by the FRMRC researchers.

Working with the FRMRC model developers, to identify any required improvements prior to the models being applied in further demonstration catchments.

Compare the results from the new 1D surface flow model with the results from the Infoworks CS 2D model.

Background: Torquay

Background: Torquay Flooding Locations

Background: Historic Flooding Locations

Market Street, Torquay - 1984

Background: Historic Flooding Locations

John Menzies Union Street, Torquay - 1986

Background: Major Flood Alleviation Schemes

Hele Tank

Ellacombe TankUpton Tank

Background: Recent Flooding Events

29th May 1999 24th October 1999 19th August 2000 20th August 2007

Background: Torquay - Dry Photos

Background: Flooding 1999

Fleetwalk/Union Street Flooding Movie- 1999

Background: Flooding 20th August 2007

Data: Data Collection

Sewer Records Mastermap Mapping Data Digital Terrain Data Aerial Photography Historic Flooding Records Rainfall Data Verified Hydraulic Model

Data: Lidar Ground Based

Data: Lidar Ground Based

Data: Lidar Ground Based

Data: Lidar Ground Based

Data: Lidar Merged Data

Data: 1D Modelling Ground Intensity Image

Data: 1D Modelling Integrated Model

Modelling

Base Model - 1D Model Enhanced Model - 1D/1D Model Integrated Model 1D/1D Model Infoworks 2D Base Model Infoworks 2D Integrated Model

Modelling: Base Model - 1D

Type 2 Model (WaPUG Guide) Originally Produced in 1993 Updated to include modifications

Modelling: Study Area

Modelling: Enhanced 1D/1D

Format Input Data for use with Imperial College Software Use Imperial College Software Produce Ponds Produce Pathways

Import Data into Infoworks Clean up data

Modelling: Enhanced 1D/1D - Input data

Data required

Modelling: Enhanced 1D/1D - Imperial College Software

Modelling: Enhanced 1D/1D - Infoworks data import

Modelling: Infoworks 2D

Base model + 2D mesh Integrated model + 2D mesh 2D Mesh 17,083 triangles based 11,263 vertices 12.43 ha max triangle area 10m2 min mesh element area 5m2 min angle 25 degrees

Modelling: Infoworks Coarse 2D Modelling

Coarse model bare earth (10 mins mesh) Coarse model with buildings (1 day mesh)

Results Infoworks 2D 24th October 1999

Results

Historic flooding locations replicated Overland flows accurately predicted in

both 1D & 2D models Depth of flooding under-predicted in 1D

model Graphical representation of 2D results

impressive

Conclusions

Objectives successfully completed Imperial Software required further

development No appreciable benefit between

Integrated and Enhanced model 1D rapid assessment tool Infoworks 2D preferred for design

solutions

UKWIR/FRMRC Integrated Urban Drainage OverviewStudy ObjectivesBackground: TorquayBackground: Torquay Flooding LocationsBackground: Historic Flooding LocationsBackground: Historic Flooding LocationsBackground: Major Flood Alleviation SchemesBackground: Recent Flooding EventsBackground:Torquay - Dry PhotosBackground:Flooding 1999Background:Flooding 20th August 2007Data:Data CollectionData:Lidar Ground BasedData:Lidar Ground BasedData:Lidar Ground BasedData:Lidar Ground BasedData: Lidar Merged DataData: 1D Modelling Ground Intensity ImageData: 1D Modelling Integrated ModelModellingModelling: Base Model - 1DModelling: Study AreaModelling: Enhanced 1D/1D Modelling: Enhanced 1D/1D -Input dataModelling: Enhanced 1D/1D - Imperial College SoftwareModelling: Enhanced 1D/1D -Infoworks data importModelling: Infoworks 2DModelling: Infoworks Coarse 2D ModellingResults Infoworks 2D 24th October 1999ResultsConclusions