Yes, says Iain Maxwell, Regional Manager of Fish & Game NZ. He’s talking about the upper Mohaka in the Taharua valley.
The source? This small area is home to a third of the region’s total dairy herd, some 9,000 dairy cows. Saturate a free-draining pumice soil with that many cows and the situation is right for the increased nutrient levels observed in the upper reaches of the river.
Says Maxwell: “The increase in nutrient is almost certainly the result of concentrated urine patches from 9,000 dairy cows leaching nutrient into the groundwater and then appearing in the surface waters of the nearby Taharua River.”
Lest one doubt the decline in water quality in this area of the river, watch this underwater video shot by Maxwell above and below the confluence of the Taharua and Mohaka Rivers. Above the point of their merger, clear water … below the merger, murky algae-ridden water.
These “above” and “below” photos are lifted from the video (click on photo to view full size) …
Maxwell notes that the Mohaka is the only river in Hawke’s Bay supposedly protected by a Water Protection Order, yet it appears to be deteriorating … in part because the Regional Council lacks the appropriate mechanisms in its Resource Management Plan to regulate the land use that is the suspected cause.
Fish & Game will be pushing the Regional Council on this issue. BayBuzz looks forward to the HBRC’s response to Maxwell’s video. We’ll be lending a hand however we can.
For more on the issue, here is Ian maxwell’s article, Dairying and the Mohaka, from the August issue of BayBuzz Digest.