1. 1 RMM Pradeep and N T S Wijesekera URBAN FLASH FLOOD MITIGATION USING A DYNAMIC HYDRO-GIS TOOL : AN APPLICATION AT THE THIMBIRIGASYAYA WARD OF COLOMBO MUNICIPAL AREA, SRI LANKA Capt RMM Pradeep & Prof NTS Wijesekera

2. 2 RMM Pradeep and N T S Wijesekera Urban Flash Flood Scientific Reasoning Rajagiriya - November 10, 2010

3. 3 RMM Pradeep and N T S Wijesekera Before Urbanization

4. Whilst Urbanization Changes to slope, soil & landcover

5. No Infiltration After Urbanization

6. Add Detention Pit Engineering Option

7. 7 RMM Pradeep and N T S Wijesekera Detention Pit Sizes ? 2009 (1986) Planning and Building Regulations of the UDA “Minimum equivalent rainwater holding provision requirement” Available Hydro-GIS Tool No Single Tool Source : The Gazette of the Democratic Socialist Republic of Sri Lanka No 1597/8 – Part I : Sec. (I ) Page :(13A)

8. 8 RMM Pradeep and N T S Wijesekera Objective Develop Rational Stormwater Management Capable Dynamic User-friendly GIS tool Capture key parameters Compute stormwater generation Compare pre and post development

9. 9 RMM Pradeep and N T S Wijesekera Identify the Key Requirements Objective Identification Literature Review Conceptual Design Software Development Testing and Modification Result

10. 10 RMM Pradeep and N T S Wijesekera Technical Parameters Parameter for User Friendliness Objective Identification Literature Review Conceptual Design Software Development Testing and Modification Result

11. 11 RMM Pradeep and N T S Wijesekera Incorporation of Modifications Comparison of Runoff Generation Dynamic Detention Pit Objective Identification Literature Review Conceptual Design Software Development Testing and Modification Result

12. 12 RMM Pradeep and N T S Wijesekera Land Management Tool Coefficient Comparison Extension Dynamic Detention Pit Extension Objective Identification Literature Review Conceptual Design Software Development Testing and Modification Result

13. 13 RMM Pradeep and N T S Wijesekera Evaluate user friendliness Accuracy of tool Objective Identification Literature Review Conceptual Design Software Development Testing and Modification Result

14. 14 RMM Pradeep and N T S Wijesekera Objective Identification Literature Review Conceptual Design Software Development Testing and Modification Result Product Delivery

15. 15 RMM Pradeep and N T S Wijesekera Study Area LayerScale Administrative boundary 1 1:10,000 Parcel layer 1 1:10,000 Soil layer 2 1:100,000 Contour layer 1 1:10,000 Land use layer 1 1:10,000 Sources: 1.Survey Dept, Sri Lanka 2.National Atlas of Sri Lanka

16. 16 RMM Pradeep and N T S Wijesekera Conceptual Design Incorporation of Land Modifications Computation of Runoff Generation Incorporation of Detention Pit

17. 17 RMM Pradeep and N T S Wijesekera On-Screen Modification Precious Modification Option Incorporation of Modification

18. 18 RMM Pradeep and N T S Wijesekera Incorporation of Modification Guided Attribute Update

19. 19 RMM Pradeep and N T S Wijesekera Comparison of Runoff Generation UnionUnion Land Use Slope Soil Composite Runoff Combined Layer Lookup Table

20. 20 RMM Pradeep and N T S Wijesekera Dynamic Detention Pit Conceptual Design Unit Hydrograph Detention Pit After Before Detention Pit Effect of the Dynamic Pit

21. 21 RMM Pradeep and N T S Wijesekera Evaluation Process (Pew & Mavor, 2007) Formative Evaluation Refine Summative Evaluation Initial Product Final Product

22. 22 RMM Pradeep and N T S Wijesekera Hydro- GIS Integration (Sui and Maggio, 1999) Source : Sui and Maggio (1999) Hydrological Modeling GIS Embedding GIS in Hydro Models GIS Hydrological Modeling Embedding Hydro Models in GIS Hydro Modeling Hydro Modeling GIS Statistical Tools Loosely Coupled Hydro Modeling Hydro Modeling GIS Statistical Tools Tightly Coupled

23. 23 RMM Pradeep and N T S Wijesekera Hydro- GIS Integration (Sui and Maggio, 1999) Source : Sui and Maggio (1999) GIS Hydrological Modeling Embedding Hydro Models in GIS

24. 24 RMM Pradeep and N T S Wijesekera Spatial Data Security Source : Sui and Maggio (1999) Spatial information Spatial Code Value Non-spatial information Non spatial Code Value Final Code Value

25. 25 RMM Pradeep and N T S Wijesekera Verifications Software Adequacy – 31 samples Cont..

26. 26 RMM Pradeep and N T S Wijesekera Verifications Formative evaluation – 34 and 31 samples Cont.. …Cont

27. 27 RMM Pradeep and N T S Wijesekera Verifications Summative evaluation– 34 samples Cont.. …Cont

28. 28 RMM Pradeep and N T S Wijesekera Verifications Tool Usability – 5 Users UserMap ReadingIT KnowledgeGIS Software knowledge 1AdvancedMS OfficeArcGIS Basics 2AdvancedMS officeNil 3BasicProgrammingNil 4 ProgrammingNil 5BasicMS OfficeArcGIS Basics Spec:Computer 1Computer 2Computer 3 CPUP IV 2.6 GHzP III 1.5 GHzCore 2 Quad 2.5 GHz RAM1 GB256 MB2 GB VGA256 MB shared64 MB Shared1 GB Separate ArcGIS Version9.2, Desktop 9.3, Desktop Users Computer Specification Cont.. …Cont User Map Reading IT Knowledge GIS S/W Knowledge ComputersCPUVGA ArcGIS Version

29. 29 RMM Pradeep and N T S Wijesekera Verifications Hydrological Calculations …Cont

30. 30 RMM Pradeep and N T S Wijesekera Technical Details ArcGIS and Visual Basic Rational Method (US Army Corps of Engineers, 1997) and Unit Hydrograph Concept Linear Tank Model – Mays (2001) 5 User Usability Testing model - Virzi (1992), Neilson (2000)

31. 31 RMM Pradeep and N T S Wijesekera GIS to Manage Urban Stromwater Considering Land Enhancement Tool

32. 32 RMM Pradeep and N T S Wijesekera On-screen Incorporation of Land Modifications

33. 33 RMM Pradeep and N T S Wijesekera Comparison of Pre and Post Development

34. 34 RMM Pradeep and N T S Wijesekera Incorporation of Dynamic Detention Pit

35. 35 RMM Pradeep and N T S Wijesekera Desktop Spatial Data Security Message display Modified parcel highlighted

36. 36 RMM Pradeep and N T S Wijesekera Research Contribution Application Unique Hydro-GIS tool to flash flood management Methods Desktop GIS data security GIS GUI guidelines Dynamic Tool Easy comparisons Independent base data Visualize

37. 37 RMM Pradeep and N T S Wijesekera GIS Tool for Urban Watershed Mangers Optimized Modification Engineering Option to Mitigate Flash Flood GIS Tool User friendliness Confidence

38. 38 RMM Pradeep and N T S Wijesekera A user friendly Dynamic GIS tool with user manual Dynamically compute the stormwater generation Dynamic detention storage facility User friendliness and user satisfaction Security and accuracy