Project: Railton Flood Mitigation
Update August 2023:
Good progress is being made by IPD consulting including the refining of peak flow rates and total flow volumes for various storm events. The concept to divert excess water into a culvert along Morrison Street to cater for the largest practical flow rate, that being equivalent to the 2011 flood event is well underway. Opportunities to upgrade the system in the future for a higher level of protection and climate change impacts when additional funding might become available are also being considered to ensure further works can be staged into the future and that the current project remains integral to the mitigation against flooding.
In late August 2023 landowners in close proximity to the proposed works were recently advised by letter which included:
Progressing design work for the Railton Flood Mitigation Project requires on-ground surveys for flora, fauna and heritage values as well as geotechnical investigations in key areas. Council has engaged consultants to do this.
This work needs to extend out beyond the footprint of the project and your property has been identified as potentially being in the general area requiring assessment.
Whilst most of the survey works will be through visual inspections, the geotechnical survey will require machinery to dig or drill inspection holes. Not all properties will require a geotechnical survey, and those that have been identified will be contacted separately prior to the works.
These surveys are planned to be undertaken when specialist consultants are available during September to December this year. The information gathered will inform the design, enabling a mitigation solution to the flooding issues in Railton to be further developed and shared with the wider community.
Our consultants will carry proof of identification with them and will door knock when they arrive on site.
If you have any general queries or specific requirements before entering your property, please make contact with Mr Paul Ellery as project manager for the Railton Flood Mitigation Project by phoning 0427 053 807 or e-mailing paul.ellery@bluetier.com.au.
Consultants will be presenting an update to councillors in early October. The intention is for the majority of works to be undertaken in the upcoming 2024/25 financial year and funding agreements are being adjusted accordingly.
Update - March 2023
Council received a draft alternative concept design and supporting option engineering assessment report from IPD Consulting and resolved at the January 2022 Council meeting to further the possibility with them. The recommendation endorsed by Council follows:
- Engage IPD Consulting to continue work on the alternative flood mitigation solution to divert water along Morrison Street in a box culvert as outlined in the Recommendations section of their memo titles Railton Flood Mitigation Project (RFMP), Option Engeineering Assessment;
- Approach State and Federal Government representatives for additional funding of 1/3 each of the latest total project estimate; and
- Advise the community of this work continuing with a current proposed project completion date of 1 November 2024.
Council officers are working with IPD Consulting to further this solution.
This work will continue noting the current Federal Government Community Development Grant project completion date of 1 November 2024.
Click here for a High Resolution version of the map: Railton Flood Map - 100 Year AEP Planning Map
Other links
Flood Information - Kentish Council
SEMF - Review of Railton Flood Mitigation Options
Railton Flood Guide - Tasmania State Emergency Service
A large flood in 2011 had a severe economic, infrastructure and environmental impact on the community of Railton when 60 houses and 14 businesses were flooded. A later event in 2016 had a lesser impact but still resulted in properties being inundated and a high level of anxiety.
Entura, the consulting arm of Hydro Tasmania, were engaged to complete a hydraulic assessment and to design a flood protection system suitable to withstand an event equivalent to the 2011 event, which was determined at the time as having a 1% chance in happening in any one year.
Community feedback indicated concern in relation to works along the creek in developed private properties as well as proposed alignments of the water course.
Recent developments with the larger mitigation project are outlined below:
- Funding agreements with the State and Federal governments have been updated to reflect the current project scope and timelines.
- The concept design consultant, Entura (the consultancy arm of Hydro Tasmania), has completed their commissioning to validate flood modelling and prepare a concept design.
- Additional consideration has been given to community feedback received late in 2021 that raised concern in relation to works along the creek in developed private properties and that alternative alignments should be further investigated.
- Localised flooding that occurred on the 3 August 2022 was observed in relation to the Redwater Creek project, noting that Council has a capital works budget allocation to improve drainage in the Foster Street area between Dowbiggin Street and Leake Street.
- Various initial improvements have been made along Redwater Creek including enlarged watercourse openings under the railway line.
An informal onsite review of a potential alternative concept design has been held with a possible contractor for the project. They raised concerns with the potential for a very limited number of suitably resourced and qualified contractors tendering on a project of this current design, risk, and magnitude.
The main reservations being that the majority of the works are located in multiple private properties which is likely to result in delays in negotiating access, and the level of detail required to scope, undertake, and reinstate so as to complete the works most efficiently and to a tight program and budget.
Given feedback from the community consultation, and specialist industry advice, the opportunity to potentially provide a flood bypass will be further assessed. Providing a bypass is not dissimilar to the design under construction for the Latrobe mitigation project, although the Railton solution is likely to be more passive in operation.
The potential alignments are similar to what appears to be an original water course located north-west of Redwater Creek or along Morrison Street, and then discharging under the Railway and connecting to Redwater Creek near the TasWater sewage lagoons.