Flooding

Volume 2G Appendix Q: Part 01 Flooding and Drainage

Ben Aveling Flooding

Volume 2G Appendix Q: Part 01 Flooding and Drainage (pdf)

Contents Pages
Glossary of terms and abbreviations vii
Executive summary xi
Overview xi
Existing environment xi
Assessment of construction related issues xi
Assessment of operational related issues xi
Assessment of potential mitigation measures xii
1 Introduction 1
1.1 Overview of the project 1
1.2 Project location 1
1.3 Secretary’s environmental assessment requirements 4
1.4 Relevant policies and guidelines 7
1.5 Study area 10
1.6 Purpose and layout of this report 12
1.7 Available data 12
2 Proposed project 14
2.1 Project features 14
2.2 Construction activities 15
2.4 Flooding and drainage related components 19
3 Assessment methodology 21
3.1 Overview 21
3.2 Adopted minimum hydrologic standards 21
3.3 Definition of present day flooding behaviour 22
3.4 Assessment of construction related impacts 23
3.5 Assessment of post-construction related impacts 23
4 Existing environment 26
4.1 General 26
4.2 Rainfall and evaporation 26
4.3 Topography 26
4.4 Catchment description 26
4.5 Characteristics of flooding 29
5 Assessment of construction related issues 31
5.1 Overview 31
5.2 Flood risk at construction ancillary facilities 31
5.3 Flood risk during tunnelling 31
5.4 Flood risk during cut and cover tunnel construction 32
5.5 Flood risk during surface earthworks 32
5.6 Flood risk during bridge construction 33
5.7 Potential impacts of construction activities on flooding behaviour 33
6 Assessment of operational flooding impacts 45
6.1 Overview 45
6.2 Operational related flood risk and project related impacts on flooding behaviour 45
6.3 Impact of project on future development of affected land 58
6.4 Potential impacts of future climate change 58
7 Assessment of potential mitigation measures 61
7.1 General requirements 61
7.2 Mitigation of construction related impacts 61
7.3 Mitigation of post-construction related impacts 64
8 Conclusion 71
9 References 72
Appendix A Overview of previous studies A
Appendix B Background to hydrologic model development B
Appendix C Background to hydraulic model development (continues in part 2 groundwater) C