3km of river habitat improvements in January!

Our phase one January projects are now complete. A series of interventions have been put in place to create 3km of connected habitat and water filtering buffer zones across two river catchments and three tributaries. This report focuses on two projects recently completed on the Clwyd.

The Clwyd Catchment is important for biodiversity and home to salmon and sea trout. An investigation into the fish populations found that salmon rod catches have been extremely low since 2013. The catchment is also in an area where the majority of land use is for agriculture.

Afon Meirchion (site 1)

Afon Meirchions’ water quality was classified as ‘moderate’ in comparison to ‘good’ for the other rivers on the Elwy. Consequently, the Afon Meirchion has been targeted for vital restoration work to improve the water quality to match surrounding rivers.

After an investigation by our lead project officer Liam Whitmore and Antony Smith, the NWRT assessed the most beneficial nature based solutions (NBS) to improve the quality of the river.

Evidence of cattle poaching near the river.

1) Issue: Livestock trampling the riverbank causing damaging silt in addition to fecal matter and urine directly entering the Meirchion. This causes anoxic conditions, killing aquatic flora, fish eggs and invertebrates.

Action: We fenced out 280m of riverbank and created a 2m riparian buffer zone along the riverbank. Previously, 40 cattle and around 200 ewes roamed freely across the pasture causing direct pollution and erosion. We also put in place drinking troughs for cattle. As their are no mains waters near this site we will install a solar pump to the troughs in the spring.

Fencing 2-5m from the river bank has created a buffer zone ready for planting.

Afon Bach (site 2)

The Afon Bach catchment suffers from road run off from the A55. The road salt is having a devastating impact on this catchment. NWRT are currently looking at NBS and the use of wetlands to mitigate run off on the upper section of the Bach.

Severe poaching along the river bank

Alongside the road pollution, the land is used for agriculture and the river often suffers from the impact of livestock and agricultural run off.

The river faced many obstructions, causing build up of debris, silt and obstruction to fish passage.

2) Issue site 2: Debris and old fencing/ building materials causing obstructions to the natural flow of the river. Livestock trampling the riverbank causing damaging silt in addition to fecal matter and urine directly entering the Bach. This causes anoxic conditions, killing aquatic flora, fish eggs and invertebrates. Exposed river bank with no habitat cover and severe poaching.

Action: We cleared debris causing obstructions in the river. Moved the existing fencing back 5m and replaced old fencing where cattle entered the river. We installed water troughs that were connected to the mains water supply on the farm, and created a 3-5m riparian buffer zone along the riverbank.

We installed drinking troughs for cattle and connected these to the mains water supply. This means no abstraction directly from the river.

Riparian buffer Zone

Lack of riparian vegetation reduces bank stability and biodiversity as well as increasing erosion. Tree planting along this stretch will have several benefits to ensure a healthy river and connected habitats.

Not only will the wetland scrapes and trees naturally filter the water, they will also provide habitat for numerous species and shelter for aquatic animals. For example, mayflies need trees to rest and to metamorphose into the final breeding stage of their lifecycle; fish will use overhanging branches and tree roots to hide from predators.

Trees will also provide leaves and woody material to the river – this is a primary input of nutrients and food for detritus shredding organisms such as Gammarus, which are important food for trout and birds such as dippers.

They provide much needed shade during periods of low flows and high temperature, reducing water temperatures and helping to maintain oxygen in the water. Too much shade can be a problem in suppressing growth of aquatic plants, but a mix of dappled light and shade is ideal. That is why The NWRT team will be designing a mosaic style plan for our buffer zones.

Liam learning about native tree populations, to create riparian buffer zones and stabilise river banks.

Lead project officer Liam says, “One of the interventions we do at NWRT is a two step approach to improving water quality. Firstly we fence out livestock and we create a minimum 2m buffer zone from the riverbank. Fencing prevents any livestock from entering rivers and streams. This reduces pollution from the livestock themselves (in the form of faeces and urine), and sediment being trampled into the water and smothering spawning grounds downstream. The second phase is the creation of natural buffer zones through deciduous tree planting and wetland strips. This buffer zone filters agricultural run off and allows bank vegetation to regenerate. Improving water quality.”

During phase 2, the team will be hard at work planting native riparian species that will be beneficial for aquatic wildlife, preventing further erosion from rain and flooding.

If you would like to join our winter 23/24 volunteer tree planting sessions, then get in touch using the contact page and put Tree Planting in the subject header.