Build up of gravel (aggradation) in rivers within the Upper Tukituki has been an issue for more than a decade. The higher elevation of the riverbeds has compromised the level of service within the scheme.
Hawkes Bay Regional Council developed a strategy for gravel management in the Upper Tukituki (UTT) with funding from the Governments Kānoa – REDU recovery fund. This reduces costs associated with extracting gravels from five rivers in the Upper Tukituki Scheme (Upper Tukituki, Waipawa, Magaonuku, Tukipo and Makaretu), making it comparable to the cost of extracting elsewhere within Hawke’s Bay.
The overall project value is $8 million with $5,120,000 grant from Infrastructure Reference Group (IRG) and $2,880,000 loan funded through UTT scheme rates, following consultation with the UTT Scheme ratepayers during the 2021-31 Long Term Plan (LTP).
Extracting gravels from rivers within Hawke’s Bay has been an effective way to increase river capacity and reducing risk of water inundation of neighbouring properties during flood events. The gravels are typically used for industrial purposes, both processed and unprocessed pending on the characteristics of the gravel and the desired use.
The limited funding generated by the UTT scheme and distance to civil and infrastructure projects within the Hawke’s Bay Region has hindered any significant gravel extraction. Reduction in gravel levies has been used to incentivise extraction within the scheme, however this has had limited success.
Without gravel extraction, aggradation will continue and reduce the Level of Service of the UTT rivers. The overall desired outcome of the project is to provide a 1 in 100 year flood protection to the UTT scheme.
To date, survey has been undertaken to determine volume of available gravel, material testing of gravels to confirm engineering properties and prioritisation of cross sections/reaches.
The Regional Council have undertaken a Registration of Interest (ROI) through Government Electronic Tendering System (GETS) to prequalify potential tenderers to undertake gravel extraction activities. Successful tenderers will be allocated cross sections/reaches to bid upon. The Regional Council shall also identify possible capital projects through Local Authorities, NZTA or other stakeholders to maximise the volume of material to be extracted.
Estimated project completion November 2023.
