With increasing variability in rainfall, rehabilitation of creeks and their floodplains is vital for retaining aquatic biodiversity.
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It's also critical for production - keeping water on farm stored in soil and floodplains grows more grass and contributes to retaining water in our landscape for longer.
This has benefits for production and our aquatic life.
The dry of the last year has had a major effect on creek flows in many of our subcatchments.
First and second order streams - those intermittent creeks and gullies that characterise the southwest slopes are suffering from the lack of winter recharge, erosion and sedimentation.
Species like the endangered southern pygmy perch, which rely on deep, permanent pools for refuge in dry times are suffering.
Creek geomorphology varies but in general when a creek gets deeper, it means the bed is actively eroding.
This speeds the water up, creates more erosion and changes pools and riffles to straightened, shallow channels.
Soil moisture from the floodplains "drains" back in to the channel instead of staying in the soil and growing grass.
As the slopes decreases downstream, the sand and sediment from erosion deposits in-stream and fills up pools and holes.
The result is less areas of open water and deep pools that can sustain populations of aquatic insects, frogs, fish and other dependent species through the dry times.
Landcare has facilitated the fencing and revegetation of creeks and gullies on farms for the last 30 years. This has contributed to terrestrial biodiversity goals, but now communities need to look at doing something in-stream if we are going to improve anything for aquatic life.
Fencing creeks to keep control of stock access is a key strategy that allows in-stream vegetation like phragmites (common reed) to grow and stabilise the floor and banks. It doesn't mean stock are excluded year-round, but you have control over what happens.
Slowing the water by vegetation and retaining and adding big woody material is important to create the turbulence and eddies that create holes and deeper waters that are refuge in drought and habitat for fish.
Holbrook Landcare recently undertook some rehabilitation with a grant from the NSW Environmental Trust's Restoration and Rehabilitation program to create habitat for the endangered southern pygmy perch to do some of this work. The group hopes to do more in the future to retain water and habitat in these systems.
There are rules for in-stream work in third-order streams in Victoria and NSW, so seek advice from your CMA or Water NSW.