RIV_2600611 Rangitata/Rakitata River Flood Resilience – Groyne Rockwork Reinstatement

Canterbury Regional Council (Environment Canterbury) (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). The Council is seeking responses to this Request for Proposal from suitably experienced contractors to undertake construction of new groyne structures on the true right bank of the Rangitata/Rakitata River, below the Arundel bridge. This contract involves the construction of four groynes. Details of works required are included in the Specifications in Part C and Construction Plans in Appendix 3. Note the number of groynes constructed may vary between two and four depending on tender prices as the project has a fixed budget for these improvements. Environment Canterbury will agree to the final scope of work with the selected contractor prior finalising contract documents. The work sites for the groynes are located on riverbed and in river berm. Access to the work sites will be via the Rangitata South Irrigation Limited (RSIL) pond access road, property owned by Rangitata Water Limited. All necessary agreements are in place with the landowner with regard to this work. Works will require the clearance of berm vegetation, removal of existing groynes, and clearance of any unsuitable material from the works area, prior to the construction of the four new groynes. It is possible that Rangitata River braids will be located near or within the proposed works site. The Contractor may therefore need to undertake diversion works to ensure that the groyne construction can proceed in the dry. The works will require the carting and placing of approximately 5500 tonne of rock from a RSIL stockpile adjacent to the site to form the new groynes. A further 9000 tonne of rock will need to be procured and imported to the site to form the further groynes. Rock from the existing groynes slated for removal may be suitable[JN1.1] for reuse and may reduce the amount of imported rock required. It is assumed that river diversion works will be required during construction of the groynes.