Causes of River pollution

http://www.newshub.co.nz/home/new-zealand/2017/02/special-report-how-polluted-are-new-zealand-s-rivers.html

Sediment: Fine material from deforestation

1. Rain falls onto deforested land

2. The rainfall spills sediment into waterways

3. The sediment forms a mat over the riverbed, cutting off life

When we get heavy rainfall events we get huge amounts of fine material from deforested areas.

This sediment comes off the land and clogs up the rivers making them brown and dirty, but the biggest impact is that the sediment then forms a mat over the bed of the stream, and cuts off all the habitat for the life in it.

Nutrients: Nitrogen and phosphorus from livestock urine and fertilizer

1. Cows urinate into the soil

2. Nitrogen from the urine travels through the soil into waterways

3. The nitrogen can create toxic algae and choke the water of oxygen

"It's not so much the nitrogen itself that's the problem, but that it's a nutrient, and it grows in the plants and the lakes, and there's algae and then algal bloom; either toxic algae, or algae that grows to such an extent that it takes the oxygen out of the river, out of the water itself and the animals die." 

Bacteria: E. Coli from livestock excrement

E. Coli comes from the faeces of animal livestock, and has become a major factor in stopping Kiwis from swimming in their rivers. E. Coli is a major health hazard - it can make you sick, especially if you drink water contaminated with it such as what occurred in Hawke's Bay in 2016.

DairyNZ regulations mean its farmers must fence off all waterways on their land and 96 percent have done so - but no such regulations exist for beef, sheep or deer farming.

Environment Minister Nick Smith wants this compulsory across all farming industries by 2030. One wonders why it has taken the Government so long to implement such a measure.

Invading species is also a massive problem

Invasive plants and animals in our waterways are still a major problem in 2017, with foreign species of fish like toy carp wreaking havoc on the natural vegetation in our Kiwi lakes, exacerbating the decline in water quality. Eg: Didymo 


Site that may be useful:
https://www.lawa.org.nz/learn