It’s a choice that’s so logical you can learn it with some pictures from the Wairarapa:
Take a plentiful mixture of suffering cows: All of their shade trees have been cut down to make room for more grass; Their tails, their natural defense against biting and stinging insects, have been cut off so they don't sling their poo around while in these forced, crowded conditions; Their grass is green from over-use of chemical fertilizer that runs off into the streams; Their meat and milk are full of antibiotics and hormones.
Add pumping of nearby streams for irrigation of that green grass that dries out so fast in the hot sun. This is ironic irrigation along the edge of the lake that was once lush, vital wetland.
Then, just a pinch of barrage gates between the river and the lake to control the flow of the water and keep native fish from migrating and the lake from freshening...
And the result is polluted streams with little water. Maybe even just some hot pools with suffocating fish. Notice also how the streambank is not fenced off from the cattle? How about some cow poo sauce?
...heaps of toxic algae as a garnish. Notice that you shouln't even handle the stuff on the river bank!
Ready for an alternative recipe?
Take a some happy, healthy cows who have shade, their own gosh-darn tails, heaps of natural grasses that don't need irrigation, and their free-roaming babies to raise without hormones or antibiotics...
Add a good fence to keep them from trampling and pooing in the nearby stream….
Toss in the greens: Heaps of native plants all around the stream to keep it cool and give good hiding spots for native fish and juicy invertebrates...
Enjoy a healthy stream filled with inanga, banded kokopu, bullies, insect larvae, and of course...
Happy, healthy kids who can swim and play with all the eels!