Page content Page content Section navigation Topic navigation Accessibility keys Sitemap Search Contact us www.govt.nz portal
Go to Waikato Regional Council homepage
search icon mail icon contact us icon

  Services » Publications » Technical reports - by year » TR200210

Report on the Thames Coromandel and South Waikato districts flood event 21 June 2002

Report: TR 2002/10
Author: Adam Munro

Abstract

This report examines the key aspects of the “Weather Bomb Event, June 21 2002”, which resulted in two Civil Defence emergencies being declared for the Thames Coromandel and South Waikato Districts. It has been produced as part of Waikato Regional Council’s internal reporting requirements.

The purpose of the report is to provide a comprehensive overview of the storm event that brought torrential rain and strong winds to many parts of the region, particularly the Thames Coromandel (TCDC) and South Waikato (SWDC) Districts. As a result, both districts declared states of civil defence emergencies. TCDC declared at 2.30am on Friday June 21 due to a significant number of homes being flooded (forcing evacuations), widespread power cuts, and water treatment issues. SWDC declared at 8am on the same morning due to public health concerns, public safety issues, and unknown extent of damage.

The event produced rainfall intensities in the order of 100mm in one hour registering return periods of 100 years and creating river levels ranging from 5 year to 100 year return interval events. Trickling hillside streams became raging torrents in just a few minutes, carrying fallen trees, boulders, and many thousand tonnes of mud through homes, properties and roads.

The report also discusses how the event was managed, what lessons were learnt, recommendations for operational improvements, and the drawing together of general event information to ensure responses to future emergencies are carried out to the best extent possible.

The Weather Bomb 21 June 2002
(1433 kb, 204 seconds to download, 56k modem) 

Table of contents

1 Introduction 3
2 The Storm 4
3 Rainfall 4
  3.1 Severe Weather Warnings 5
4 Wind 6
5 Barometric Pressure (BP) 6
6 River Levels 7
  6.1 June Climate Update 9
  6.2 July to September Outlook 9
7 Flood Warnings 9
8 Civil Defence Response 9
9 Media Releases 10
10 Extent of Damage 10
  10.1 Environment Waikato (EW) 10
    10.1.1 Coastal Areas 10
    10.1.2 Waihou Valley Scheme 10
    10.1.3 Piako River Scheme 11
    10.1.4 Thames Valley Drainage Area 11
    10.1.5 Scheme Performances 11
    10.1.6 Issues 12
    10.1.7 Emergency Works Undertaken 12
  10.2 Thames Coromandel District Council (TCDC) 15
    10.2.1 Observations 15
    10.2.2 Proposed Actions 16
  10.3 South Waikato District Council (SWDC) 17
    10.3.1 Observations 17
    10.3.2 Proposed Actions 18
  10.4 New Zealand Fire Service 18
  10.5 WEL Energy 19
  10.6 United Networks 19
  10.7 Tranzrail 20
  10.8 Transit New Zealand 20
  10.9 Telecom 20
  10.10 Insurance Industry 20
  10.11 Work and Income New Zealand (WINZ) 21
  10.12 Health Waikato Limited 21
  10.13 Damage Reported from other Areas 21
11 Summary of Costs 22
    11.1.1 Estimated Costs to Repair Scheme Assets (EW) 22
    11.1.2 TCDC Response & Damage Costs 23
    11.1.3 SWDC Response & Damage Costs 23
    11.1.4 Agency Response Costs (Summarised) 23
    11.1.5 Total Cost of Weather Bomb Event 23
12 Operational Improvements 23
    12.1.1 Emergency Management Room set-up 23
    12.1.2 Emergency Management Staff Roster 24
    12.1.3 Review of the Flood Warning Telemetry System 24
13 Follow-up Actions Required 25
14 Conclusions 26
Appendix A: Severe Weather Warnings 27
Appendix B: Regional Rainfall Totals 33
Appendix C: Regional River Levels 39
Appendix D: Media Releases 42
Appendix E: Debrief Memos 44
About this site     Contact us     Feedback and complaints