An artificial island is planned for York’s River Ouse, to boost the natural life of the waterway.
Plans are in to create a ‘floating ecosystem’ on the river next to North Street Gardens on Wellington Row.
Created by Scottish firm Biomatrix, which specialises in wetland habitat restoration, the island would be maintained by environmental York charity St Nicks.
The floating ecosystem would be made from modules made of plastic floats bound together with stainless steel. It would be anchored to the river wall by North Street Gardens.
Between 20 and 30 aquatic plants would be planted in the coconut fibre, or coir, covering the pontoon and the roots would be in the water. “Once established (after 1 year) the ecosystem will look like natural river side habitat,” planning documents state.
“Floating Ecosystems are engineered to improve water quality within rivers, lakes, ponds and canals as they increase aquatic life, leading to a balanced and revitalised waterscape,” the documents go on.
They can be “the injection of life an area needs, as the islands provide an opportunity for nature and wildlife to take hold”.
Not affected by flooding
Measuring 16.45m by 2.34m (54ft by 7.6ft), the floating ecosystem would be attached to the river wall. It would “rise and wall with flood levels meaning it will not be seen from the gardens which are within a conservation area, unless people directly look over the boundary fence,” a design statement says.
“The floating ecosystem will be more visible from the opposite riverbank which is mostly made up of hospitality businesses.”
Its location means it could only be accessed from the river, “ensuring there is no safety concerns of antisocial behaviour,” the statement adds.
How floating ecosystems work
“Islands break up open water surfaces and provide shade under water. Microbes in amongst the plant roots break down pollution and nutrients, and are a shelter and feeding ground for small fish.
“The water purifying function can be aided with adding mechanical aeration or fountains to bring movement and oxygen into the water. Birds can find an undisturbed nesting and resting space in areas where there is often little safety.”
Source: planning documents
“For most of the year the ecosystem will float between 3-4 metres below the top of the river wall and the gardens.
“During high flooding the ecosystem will rise with the flood levels but the gardens are closed off as a flood defence when the water level approaches the gardens. Therefore, the ecosystem will still not be accessible when it rises with flood water.”
There have already been meetings to discuss the project with City of York Council, the Environment Agency and the Canal and Rivers Trust, who have “navigational responsibility for the river and have approved the project”.
Public engagement about the project will take place in the summer. You can read and comment on the plans here.