The river Wye is a chalk stream internationally rare due to the geology and therefore a key habitat in the Chilterns. We are lucky enough to have 9/200 of the worlds chalk rivers in our area of outstanding natural beauty.
As the Wye flows from its source to the west of High Wycombe in the verdant Radnage valley, it soon becomes an urban river.
It has been abused by humans over the years in a number of ways: we have straightened and culverted (put in a pip underground), weirs installed (which are a big problem for fish passage) meaning its is often far from a river and more like a canal- which is no way to treat such an important river.
Where possible and in partnership with many others Environment Agency, Ccs as part of Revive the Wye
We are working to restore it as much as possible to a more natural state with meanders and colourful vegetation such as yellow flag and purple loosestrife in the margins.
As we try to restore the ecological and morphological balance we are sometimes limited by concrete river banks and beds.
Sometimes we are limited by actual beds too but fly tipping and litter is a different topic !
The berms are roughly semi circular, their uprights are made from chestnut stakes (chosen for their high tannin content and thus long life in water) which are driven into the river bed. We then weave branches such as hazel and sycamore. These have been scavenged from nearby projects – can you spot a coppice hazel stool in Wye Dene????
These branches are then wired into place . In time, river vegetation reeds bulrushes sedges and flowering plants like water mint and marsh marigold takes hold providing nesting and foraging habitat for ducks, moorhens, coots and even Water Rail! The invertebrates these plants flowers attract provide food for Grey wagtails and at night Daubenton’s bats!
The berms create meanders in the stream and help narrow the stream to speed up the flow. This is critical as it washes the gravel and this flow speed keeps silt from being deposited in the main channel.
This clean gravel with oxygen rich water is perfect for fish to spawn in and a key driver for this whole project.
The deflectors – logs pinned into the bankside and go into the water at an angle . We use logs from tree works in the local vicinity – such as the Bassestsbury Lane Cycle way. These complement the berms doing similar job scouring the gravel but also creating slack water.
This is where vegetation such as Brookline the wonderful scientific name for which is Veronica beccabunga can become established and this different part of the river supports a different assemblage of plant and invertebrate life.
This is only half the story though….
Under the water, the woody debris is a vital & safe (ish) hiding place for the rich variety of aquatic life of a chalk stream. Invertebrates in their larval form can grow in relative safety until they are ready to leave the water. When conditions are right, they hatch and fly off – be it for a spring day like the Mayfly or for several wonderful weeks in the summer like dragonflies and damselflies.
The underwater cover is also a refuge for brown trout fry and small fish like 3 spiked stickleback – unless they are picked off by the marauding yet elegant little egrets or diving bombing Kingfishers.
These small changes bring a more natural look and feel to the river and help restore it to one teeming with life.
Please help us keep it this way:
1 Don’t drop litter
2 Use water wisely at home. Every litre we use is a litre taken out of this precious ecosystem.
3 Join us on a volunteer session to help look after the river and it’s wildlife
See photos below of river before berms were installed.
See photos below of the making of the berms