Thousands of planned houses have been placed on hold due to water pollution in the Stodmarsh Nature Reserve just outside of Canterbury. The contaminated water has paused the construction of the controversial Mountfield Park in Canterbury, which would see 4,000 new homes. It has also stopped 725 additional houses being built in Conningbrook Lakes in Ashford, with numerous other developments in the surrounding areas affected.
The Stodmarsh Reserve is a popular spot for dog walkers and nature lovers. This unique area of wetland, with reed beds, grasslands and woodland, provides an environment rich in wildlife. It is home to many bird species and also houses the rare water vole and the ‘Shining Ramshorn Snail’.
River and water pollution stops housing development
Local councils were made aware of the water issue when a survey completed by Natural England last year revealed that there were high levels of phosphorus and nitrogen in the Stour.
Councils need to provide housing for residents and they need to meet development targets, but they are now faced with uncertainty about how to build in this large area when water courses in Kent are getting more polluted.
Green Party Councillor, Liz Wright, from Ashford said, “We should be protecting our natural environment and our heritage as a top priority and we have to combat this environmental catastrophe in any way that we can. If we need to stop building to think about this then that’s what we need to do. This is a warning of how seriously modern agricultural processes are impacting the environment with all these pollutants. We need to take a moment to pause.”
Future housing must be nutrient neutral
Experts have advised that future developments can only go ahead if they are ‘nutrient neutral’. This means that they cannot add any further to the current level of nutrients in the water supply.
The reserve is home to various wildlife which is being put at risk by increasing levels of nutrients. Natural England said, “These nutrient inputs are currently thought to be caused mostly by wastewater from existing housing and agricultural sources. The resulting nutrient enrichment is impacting on the Stodmarsh site’s protected habitats and species.”
East Kent authorities are currently working on a unified approach to improve the water quality and enable housing developments in the area to continue.
Eutrophication in our rivers
The excess nutrients in the Stodmarsh water supply lead to a process called eutrophication.
When a water supply becomes overly nourished with nutrients like phosphorus and nitrogen, algae begin to grow and thrive. The algae form a layer on the surface of the water, blocking out the sun to the wildlife below.
Over time, this lack of sun will kill the plants at the bottom of the lake and this allows bacteria which are more suited to this environment to multiply. These bacteria take in oxygen and give off carbon-dioxide, resulting in an oxygen deficient environment which will eventually kill the fish.
This process starts in the rivers and lakes but it then runs into the sea, having a much larger effect on marine life as a whole.
Over 97% of the Baltic sea is affected by eutrophication and this vast area is particularly difficult to manage due to five large rivers which filter into this sea.
Environmentalists are seeking to reform traditional agricultural processes to prevent run off waste from entering the water supply.
But the pollution also comes from household sewage as the waste works are allowed to discharge overflow into the water courses.
The plan at Sturry to capture household sewage
In Canterbury, a development near Sturry has suggested plans to have a large sewage containment tank buried in the ground to capture all the household waste. This would need to be emptied by the council and taken away from the site.
Residents objected to this model, with many saying it would be difficult to manage and would create congestion as the waste needs to be removed by road.
Local resident David Wadmore, 72, of The Hamels said, “Sturry has suffered from the effects of pollution for a long time. One of the big problems in this area is the road network. It is quite poor and there is no money for infrastructure. The people of Sturry are not against future developments but we think the council needs to make their plans sustainable and they are currently not doing this. The council needs to look at investing in public transport and making the ‘park and ride’ free instead of relying on developers to pay for the community as part of their contracts. They can have pretty incompetent planners who won’t admit if they have made a mistake.”
New targets need money
Natural England has put together a series of steps that developers in Kent can follow to meet the new targets of nutrient neutrality and prevent nutrients entering the water. These include councils creating a nutrient budget with a precautionary buffer to avoid any significant rises in the nutrients in the water courses. But a successful plan has not yet emerged enabling the councils to move forward.
Experts are currently investigating the wastewater treatment works that discharge into the River Stour and the connection to the water pollution of the Stodmarsh Nature Reserve. This report will be available in 2022.
Update 1 July
Applications for farm planning are also being held up in Kent, in the Stour catchment area, because of the problem of potential increase in phosphate and nitrate run-off, according to the Farmers Weekly. This, says the FW ” is required as a result of a European Court of Justice (ECJ) ruling in a case known as the “Dutch N case”, which centred on the need to comply with the Conservation of Habitats and Species Regulations 2017.”