Central Hawke's Bay Wastewater Inflow and Infiltration Management

⁠⁠⁠Central Hawke’s Bay District Council (“Council”) have identified a need to minimise inflow and infiltration (I&I) to the wastewater networks serving a number of communities whose Wastewater Treatment Plant (WWTP) discharges are due to be reconsented. These communities are:

• Waipukurau
• Waipawa
• Otane
• Takapau
• Porangahau and Te Paerahi

Current wastewater discharge consents require I&I management plans which demonstrate reductions in I&I. The high levels of inflow and infiltration (I&I) from rainwater and groundwater entering the sewer network poses a risk to the current wastewater upgrade projects, “The Big Wastewater Story” in terms of potential for higher capital costs (than necessary) and inefficient operation. Given the scale of investment anticipated it is important the design of the scheme is optimised which includes the reduction of network flows through managing I&I in order to efficiently size the wastewater treatment facilities and to minimise potential for uncontrolled discharges to the receiving environment.

The scope of work in this contract consists of two distinct types of work as follows;

• Investigation and identification of I&I sources across the networks. This work includes the implementation and management of the strategy to discover these sources over the course of the contract period
• Repairs to and / or replacement of specific assets to mitigate and reduce the incidence of I&I across the networks