Pokeno wastewater scheme - an innovative solution to complex hydraulics

Pokeno is situated on the south side of Bombay Hills complete with shallow basalt, undulating topography, 1,200 population on septic tanks, and an approved 800 lot subdivision due to come on stream this year. Currently serviced only by septic tanks, GHD were tasked by Waikato District Council (WDC) with design of a wastewater scheme for a target population of 7,500 people in 2040, which needed to work within the constraints of limited budget, significantly increasing flows over time and sewage age, odour and septicity caused by the need for a 8.4km rising main to Tuakau. This paper describes the solution that was developed to meet these challenges – including scheme staging options, cash flow, funding strategies and innovation in the design process e.g. Esflow Storage and low pressure reticulation systems.