- In the last 150 years, sedimentation has been 22 times greater than the last 10,000 years!
- Approx 500,000 t of silt surges down our rivers to be deposited in Bay of Islands waters every year.
- That's 2.4 mm on the seabed each year.
It covers shellfish beds, displaces kelp forests, turns rock seabeds to mud, and extinguishes important deepwater habitats.
Where it comes from
- Beef and dairy farming contribute 51%.
- Clear felled pine forests contribute 19%.
Native forest and manuka scrubland contribute a miniscule 5%, even though they make up 20% of the land cover.
What can we can do to reduce it?
Riparian planting, wetland restoration, sediment traps – and generally being savvy about slowing rates of runoff during heavy rains – can reduce the dirtying of our waters and minimise sedimentation.
Fish Forever's sister working group Living Waters has three riparian planting projects currently underway, all volunteers welcome!