Wroxall Stream is a rural waterbody that flows for 8km in a northerly direction from the Island’s southern downs to Great Budbridge where it joins the Eastern Yar river.
The watercourse is classed as ’failing’ due to the composition of macrophytes (aquatic plants) and high levels of phosphates. Invasive Non-native species (INNS) are listed as a contributing factor to the failure. It flows into the Eastern Yar which has issues with high levels of nitrogen accumulating in Bembridge Harbour.
Working with local experts, landowners, contractors and volunteers Natural Enterprise co-ordinated a suite of projects designed to arrest the flow of sediment containing phosphate and nitrate into Wroxall Stream and one of its tributaries.
The agricultural land around Arreton is criss-crossed by agricultural drains. These can be a source of phosphate and nitrate. The drains are often broken and water appears in the floodplain before finding its way to the stream.
Working with two local landowners we have created two small and one large wetlands, planted with reeds. It is hoped that once established, they will filter the water before it enters the watercourse.
Lightening the riverbank
Herbs and grasses play an important role in arresting the flow of sediments into rivers. Their roots also bind the greensand through which the river flows, giving the soil a structure less likely to erode. However when the riverbank becomes overgrown with trees, brambles and invasive non-native plants, the natural vegetation is shaded out. In places on Wroxall Stream there is a need to redress the balance and remove a small amount of trees and scrub. This is good for the river as well, as fish like to have sunny and shady spots.
We planted over 1600 native trees. Most of these were in a field by a tributary of Wroxall Stream where they will help to intercept and uptake diffuse sources of nitrogen and phosphate from higher intensive arable fields before it reaches the tributary.
And a few small interventions
Not everything needs to be big to be effective. By resurfacing this poached muddy gateway we hope to stop sediment entering a tributary of Wroxall Stream. Strategically placed coir logs will hopefully arrest the flow of sediment from these ditched and from a bridleway.