"This is also approximately 8km upstream of the Manawatū River at the end of Kakahukura Rd which we understand to be approximately the location the fisherman was referring to."
Both the Tamaki River and the Kumeti (Mangapuaka) stream flow into the Manawatū between Timber Bay at the road end and the Oruakeretaki joins it a short distance downstream.
"The Tamaki, Kumeti and Oruakeretaki were all visited on Monday for periphyton monitoring, as was the Manawatū at Weber Rd [upstream of the Mangatera confluence] and Manawatū at Hopelands [approximately 20km further downstream]," Patterson said.
"I am confident that we have a reasonable coverage of the river in this reach and surrounding major tributaries."
Samplers have noted the presence of cyanobacteria at some of these sites and also filamentous green algae.
"This is consistent with a period of extended low flows and high water temperatures at this point," Patterson said. "Generally speaking there is a lot of periphyton around the region at the moment because of these weather conditions."
Mulinder believed the stench was coming from human waste in the river, but Patterson said the sampling team did not note anything unusual in the Manawatū or any of the aforementioned tributaries, nor anything that would be linked to a wastewater treatment plant discharge outside of normal periphyton growth.
"Due to the extended period of low flows, it is very likely that periphyton has been exposed and is slowly degrading which can result in a smell or unpleasant appearance," he said.
"Likewise, cyanobacteria can result in a musty smell at times that can be quite noticeable and it is likely these factors explain what the complainant experienced."