Asburton River North Branch Stopbank

Overview Environment Canterbury Regional Council (Canterbury Regional Council, the Council, the Principal) is seeking a suitably experienced contractor to construct a new stopbank on the North Branch of the Ashburton River (NBAR). About The Council has a statutory function under the Soil Conservation and Rivers Control Act 1941 to manage land use within the region to prevent and mitigate damage caused by floods and erosion (see s126 of the Act). In the 2021 Ashburton Floods, a breakout flood at this location caused extensive damage and risk to life. A stretch of approximately 4 km of the river around Shearers and Walkhams Road, where this breakout occurred, has been identified as an ongoing major flood risk. This reach is significantly narrower than the general stopbank-to-stopbank width in the North Branch of the Ashburton River, increasing the likelihood of a breakout. Severe aggradation through this reach has also caused the river to be perched well above the surrounding land, decreasing the capacity of the river and increasing the out-of-river flow risk. Modelling conducted of the whole NBAR identified an opportunity to address some of this risk, through relocation of the stopbank and widening of the river. Purpose The Council is proposing to construct a new stopbank to address the identified flood risk through relocation of the stopbank and widening of the river. Scope The scope includes: Extraction of approximately 35,000 to 40,000 cubic metres of gravel from the reach Construction of approximately 770 metres of new stopbank Deconstruction of the existing stopbank Site preparation for the new stopbank Gravel extraction to supply stopbank construction material Stripping and stockpiling of topsoil Placement and compaction of gravels to form the new stopbank Deconstruction of the existing stopbank and placement of this material to form groyne bunds to protect the new stopbank Gravel will be extracted from the river under the Council's resource consent to undertake works in the river, and the Council's gravel authorisation. Contractor Requirements Suitably experienced contractor who will work collaboratively with the Council and its professional advisors to deliver an outcome which fully meets all time, stakeholder requirements, cost and quality objectives Contract Terms and Conditions Construction of the new stopbank is proposed to start in November/December 2026