Minimsing environmental impact through a targetted river discharge approach

The townships of Waipukurau and Waipawa in the Central Hawke’s Bay currently discharge treated wastewater (effluent) directly to the Tukituki and Waipawa Rivers respectively. In 2011 a new scheme was proposed to prevent a large portion of the effluent from entering the rivers and irrigate it to two large parcels of land, planted as production forestry. Considerable periphyton growth occurs within the Tukituki River system during summer. Generally the periphyton growth is phosphorus limited. For this reason both Central Hawke’s Bay District Council and Hawke’s Bay Regional Council are trying to reduce the phosphorus entering the river from the effluent discharge.

This paper discusses involvement that Pattle Delamore Partners Limited has played in developing the Dual Discharge scheme for Waipukurau and Waipawa. The scheme which proposed to dispose of effluent to both land and river and store effluent when neither form of discharge was available. It was expected to remove about 50% of the total volume of effluent from the Tukituki River system.