Territory Stories

Alice Springs Flood Investigation and Floodplian Mapping Study

Details:

Title

Alice Springs Flood Investigation and Floodplian Mapping Study

Creator

WRM Water & Environment Pty Ltd; Northern Territory. Department of Lands, Planning & the Environment

Editor

Roads, Greg

Collection

E-Publications; PublicationNT; E-Books; EXTA1463

Date

2015-10-12

Location

Alice Springs

Description

Made available via the Publications (Legal Deposit) Act 2004 (NT).; WRM Water & Environment (WRM) was commissioned by the Department of Lands & Planning (DLP) to undertake a flood study of the Todd River in the Alice Springs area. The aim of the study is to develop a 2 dimensional flood model, which allows flood flow in a complex flood plain to be modelled, to determine the extent and severity of riverine flooding in the town of Alice Springs and the Alice Springs rural area south of Heavitree Gap. The purpose of the study is to produce floodplain maps of the Alice Springs and its rural area for land use planning and counter – disaster purposes. This study is an extension of the Alice Springs Farms Area Floodplain Mapping Study (WRM, 2006), undertaken by WRM on behalf of the Department of Planning & Infrastructure in 2006 in order to develop detailed Todd River floodplain maps for the rural area south of Alice Springs.

Table of contents

1. INTRODUCTION -- 2. CATCHMENT DESCRIPTION -- 3. AVAILABLE DATA -- 4. CALIBRATION AND AND VERIFICATION EVENTS -- 5. HYDROLOGIC MODEL CALIBRATION AND VERIFICATION -- 6. HYDRAULIC MODEL DEVELOPMENTLOPMENT -- 7. HYDRAULIC MODEL CALIBRATION -- 8. FLOOD FREQUENCY ANALYSIS -- 9. DESIGN EVENT HYDROLOY -- 10. DESIGN FLOOD LEVELS AND EXTENTS -- 11. CONCLUSION -- 12. REFERENCES

Language

English

Subject

Flood control -- Northern Territory -- Alice Springs; Flood damage prevention -- Northern Territory -- Alice Springs; Floodplain management -- Northern Territory -- Alice Springs; Alice Springs Flood Investigation; Floodplain Mapping

Publisher name

WRM Water & Environment Pty Ltd

Place of publication

Darwin (N.T.)

Series

EXTA1463

Format

vii, 95 pages : colour maps ; 30 cm.

File type

application/pdf.

Copyright owner

Check within Publication or with content Publisher.

Parent handle

https://hdl.handle.net/10070/259732

Citation address

https://hdl.handle.net/10070/494349

Page content

0269-02-C1 12 October 2015 79 10.3 FLOOD EXTENTS Detailed flood extent and depth maps for the various design floods are provided in Appendix A. The extent of the predicted floodplain for each design event is discussed below. It is of note that the DEM available for use in the study does not cover the full extent of the eastern Emily Creek floodplain, and as such it should be noted that flooding from Emily Creek extends beyond the model extents. 10.3.1 20 Year ARI Flood Figure A.1 shows the extent of flooding and depth profile for the 20 Year ARI design flood. The following is of note: Upstream of Wills Terrace floodwaters are generally confined to the Todd and Charles river channels. Part of the eastern overbank immediately upstream of the Stott Terrace bridge is inundated, including the botanic gardens and the grounds of nearby properties. A number of properties on the eastern bank of the Todd River south of the Tuncks Road causeway are inundated to depths of up to 0.3m above ground level. Floodwaters overflow the western bank of the Todd River about 200m upstream of Stephens Road inundating the nearby properties. The overflowing floodwaters drain in a south-west direction via Gap Road towards the Stuart Highway before entering the stormwater drain adjacent to the railway, which discharges to the Todd River upstream of Heavitree Gap. The south-western corner of the Convention Centre carpark is inundated. The Stuart Highway may be inundated to shallow depths north of Heavitree Gap due to backwater flooding from the Todd River into Chinaman Creek and the stormwater drain adjacent to the railway. Between Heavitree Gap and the Ross Highway bridge, floodwaters are confined to the Todd River channel. Part of the Ross Highway south-east of the bridge is inundated to a shallow depth (by 0.3m), which is still likely to be trafficable. The Ross Highway is overtopped at the Stegar Road drain (by 0.2m) due to local catchment runoff, which is still likely to be trafficable. Floodwater overflowing from the Stegar Road drain upstream of the Ross Highway drains east through properties between Baldissera Drive and Heenan Road before draining south-east towards the Todd River at Amoonguna. Floodwaters overflow south from the Todd River channel at the racecourse, draining in a south-easterly direction across the AZRI site towards the western edge of the rural residential area on Colonel Rose Drive. Floodwaters overflowing from Ilparpa Swamp drain along an the St Marys Creek channel in a confined manner before spreading out upstream of Colonel Rose Drive; Floodwater overflowing from the Todd River at Heffernan Road drains south at a shallow depth through existing rural residential properties towards Colonel Rose Drive. Floodwater also overflows from the Todd River channel east of Chateau Road, inundating properties at the north-eastern corner of the rural residential area. The southern areas of Ragonesi Road and Stegar Road are inundated. Much of the land between the Todd River main channel and the community of Amoonguna is inundated where an old flood channel is located. The Amoonguna settlement is not inundated;