It’s been raining!
As the water runs off the land and into the creeks running into the wetlands, it picks up sediment and the water becomes turbid (muddy). We measure this turbidity with the NTU scale – 1 is a clear water sample and 100 is quite muddy but it can go higher (Lake Mokoan at its worst was up to over 200 NTU).
At our recent water quality testing run, Restoration Scientist, Dr Lisa Farnsworth, discovered first-hand the value of wetlands filtering out sediment and contaminants from water. Water runs into part of the wetlands at 11 Mile Creek and the turbidity was 60 NTU (image 1).
The water then travels through the series of shallow wetlands and into Boggy Bridge Swamp. Lisa measured the turbidity at the point where the water flowed from Boggy Bridge and into Green’s Swamp. At this point, after being ‘filtered’ by the wetlands, the water was 5 NTU (image 2), the cleanest we have recorded for some time!
This is a great example of the wetlands performing a vital “ecosystem service” of water quality treatment. The wetlands essentially act as the ‘kidneys of the landscape’, filtering and capturing sediment, and helping settle it to the bed of the wetland and the plants use these nutrients to grow which supports the whole ecosystem.