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Floodplain Risk Management Study and Plan

Wee Waa Levee Risk Management Study & Plan

Study Objectives

Narrabri Shire Council commissioned the Levee Risk Management Study and Plan for the township of Wee Waa. The overall objectives of the Levee Risk Management Study (LRMS) were to assess the impacts of flooding, review existing Council policies as they relate to development of land in flood liable areas, consider measures for the management of flood affected land and to develop a Levee Risk Management Plan (LRMP) which:

  • Proposes modifications to existing Narrabri Shire Council policies to ensure that the development of flood affected land is undertaken so as to be compatible with the flood hazard and risk.
  • Sets out the recommended program of works and measures aimed at reducing over time, the social, environmental and economic impacts of flooding.
  • Provides a program for implementation of the proposed works and measures.

While the LRMS focuses principally on the existing, continuing and future flood risk associated with the urbanised parts of Wee Waa which are bounded by an 8.6 km long earthen ring levee (Town Levee), recommendations for managing the flood risk in a 228 ha area which lies to the south-east of Wee Waa which is zoned R5 Large Lot Residential are also set out in the report.

Study Activities

The activities undertaken in this LRMS included:

  1. Undertaking a consultation program over the course of the study to ensure that the Wee Waa community was informed of the objectives, progress and outcomes over the course of the study. Consultation was also undertaken with the insurance industry to gauge the likely reduction in insurance premiums that would be achieved by upgrading the Town Levee.

  2. Undertaking of a preliminary geotechnical assessment of the condition of the Town Levee.

  3. Analysis of historic stream flow data to update the flood frequency relationship that has been derived for WaterNSW’s Namoi River at Mollee stream gauge.

  4. Updating of the hydraulic model that was developed as part of the Wee Waa Levee Flood Investigation (URS, 2015), as well as the development of a new hydraulic model which was used to define local drainage patterns internal to the Town Levee.

  5. Assessment of the economic impacts of flooding, including the numbers of affected properties and estimation of flood damages.

  6. Review of current flood related planning controls for Wee Waa and their compatibility with flooding conditions.

  7. Strategic review of potential floodplain management works and measures aimed at reducing flood damages, including a freeboard analysis for the Town Levee and an economic assessment of several measures.

  8. Ranking of works and measures using a multi-objective scoring system which took into account economic, financial, environmental and planning considerations.

  9. Preparation of a draft LRMP for Wee Waa.

Additional Information

Field Value
Title Wee Waa Levee Risk Management Study & Plan
Commission Date 1 December 2018
Publication Date 1 December 2019
Themes Land and Resource Management
Spatial Extent
Map data © OpenStreetMap contributors
Council/LGA Narrabri Shire Council
Author/ Prepared by Lyall &Associates Consulting Water Engineers
Publish date 20 April 2020
Update date 24 April 2020
Place Name Wee Waa
Approval State Approved
Submitted for approval 23 April 2020
Submitted by Tom Rooney
Approved 25 April 2020
Approved by ses-sysadmin
Identifier e6f9a45f-c295-4572-97e8-f3837a9fd082