Earnscleugh resident Lynne Stewart discusses the effect irrigation has on rivers in a continuation of our Protecting our Water series.
Our Manuherikia River water is valued for health, for life. Human health for recreation, as well as aquatic ecosystems’ health.
Historically, Central Otago irrigators can take almost all this Manuherikia River water using gold-mining permits that do not expire until 2021.
Our natural environment is fast being lost and our rivers diminished here in Central Otago.
Why do irrigation schemes get way more water than we, the public, who use our rivers for recreation, and aquatic life and ecosystems? If there are galaxids or any of our native fish, maybe even eels, in our Manuherikia River, they surely couldn’t survive hot days in tiny amounts of water that would soon heat up with no shade and no riparian planting.
I ask this after walking up the Manuherikia recently way beyond the Galloway flats, to where the Manuherikia River is unevenly divided.
Galloway irrigation gets most of our Manuherikia River water. A photo looking upstream from the divide shows all the Manuherikia River water that comes down to a location about 9km upstream of the Galloway Rd bridge.
A subsequent photo shows stones and shingle that have been bulldozed to allow a good amount of water to go down a channel to the Galloway weir/water races, off to the right [of the photo], and on the left the tiny amount of water to go down the riverbed to be our “Manuherikia River” at Shaky Bridge.
These photographs accurately reflect what is currently occurring at the Galloway Irrigation Society water intake.
Otago Regional Council information provided about the Galloway Irrigation Society consent says: “The irrigators’ wall [from riverbed gravels] shall be no more than 5m wide at the base, 3m wide at the crest and 1.5m high at the downstream face, and extending not more than 50m into the river channel from the left bank.”
The consent says the public, using the Manuherikia River, “receive a water depth of at least 150mm and a water width of at least a 300mm, for their recreation and to maintain fish passage”.
Fifteen centimetres deep by 30cm wide. This is the small amount of water that goes on down the river and, when we were walking there, was seldom more than ankle deep. Close to the Shaky Bridge, our Manuherikia River water smells bad and is full of slime.
Central Otago – A World of Difference?