River pollution and nutrient neutrality


This month, North Dorset CPRE’s Derek Gardiner looks at our rivers, which have become the latest rural planning application hurdle

Algal blooms consume oxygen from the water, undermining the river ecosystems and habitat

“Getting a complete overview of the health of our rivers and the pollution affecting them is hampered by outdated, underfunded and inadequate monitoring regimes. It is clear, however, that rivers in England are in a mess. A ‘chemical cocktail’ of sewage, agricultural waste, and plastic is polluting the waters of many of the country’s rivers”. This was the opinion of the House of Commons Environmental Audit Committee in its report published in January 2022.
The main sources of pollution outlined in the Committee’s report are agricultural pollution (affecting 40 per cent of water bodies), sewage and wastewater (36 per cent) and run-off from towns, cities and transport, referred to as urban diffuse pollution (18 per cent).
According to Sir James Bevan, chief executive of the Environment Agency, the quality of water in English rivers is “flat-lining”, with the farming and water treatment sectors being the main polluters. One of the major concerns is the excessive concentration of nutrients which causes algal blooms. These consume oxygen from the water, in the process undermining the ecosystems in rivers and the surrounding habitats. Nitrogen and phosphorous are naturally present in the environment – in low quantities, they are necessary nutrients. However, the high levels of nitrates found in sewage, agricultural run-off, nitrogen-based fertilisers and manure pose a problem requiring active management to resolve.
Since the UK left the EU, the Water Framework Directive (WFD), an important mechanism for assessing and managing the water environment, has been revoked. It has been replaced by similar legislation so that the UK continues to fulfil its reporting requirements under the new legislation.

Planning standstill
Following a landmark European Court ruling in 2018 (the Dutch Nitrogen Case, commonly known as Dutch-N), the government agency Natural England issued advice directing councils not to approve developments that would add to the nutrient pollution in watercourses in protected habitats, where the site in question is already judged to be in an “unfavourable condition”. In other words, the level of phosphorus and nitrogen in the watercourses should not increase (“nutrient neutrality”) as a result of such developments being built.
Figures provided by the Chief Planner, as of March 2022, showed that 74 local planning authorities have received nutrient neutrality advice from Natural England across 27 catchments, amounting to 14 per cent of England’s land area. In these areas, the granting of planning permission has been delayed until appropriate mitigation can be secured. According to the Home Builders Federation (HBF), this has led to proposals for an estimated 100,000 homes being put on hold. HBF companies have had to spend anything between £5,000 and £25,000 in order to procure works privately to mitigate potential nutrient pollution from new housing development.

The high levels of nitrates found in sewage and agricultural run-off require active management

Impact on Dorset
On 16th March 2022, Natural England notified Dorset Council of its updated advice for development proposals that have the potential to affect water quality, resulting in adverse nutrient impacts on internationally-protected habitat sites. This advice applied to the catchments of five habitat sites which together cover a large part of the Dorset Council area.
The advice was that Dorset Council should “carefully consider the nutrients impacts of any new plans and projects (including new development proposals) on habitats sites and whether those impacts may have an adverse effect on the integrity of a habitats site that requires mitigation, including through nutrient neutrality”.
The catchment areas within Dorset that this relates to are:
Poole Harbour
nitrogen and phosphorus nutrient deposition
Somerset Levels and Moors phosphorus nutrient deposition
River Avon
phosphorus nutrient deposition
Chesil and The Fleet
nitrogen and phosphorus nutrient deposition
River Axe
phosphorus nutrient deposition
The problem of nutrient pollution is particularly pronounced in Poole Harbour.
In a letter from Cllr Spencer Flower, Leader of Council Dorset Council, to The Rt Hon Michael Gove MP, Cllr Flower wrote “An upgrade of phosphorus removal at all wastewater treatment works over 250 population equivalent within the catchment, as originally suggested through the Levelling Up and Regeneration Bill (LURB), would easily provide the reduction needed to achieve the target limit for phosphorus input to the harbour. This would therefore remove the need for phosphorus neutrality, enabling development to continue”.
The current draft of the LURB proposes that upgrades to wastewater treatment works serving 2,000 or more population equivalent should be the target. Cllr Flower has requested that this be reduced to 1,000 population equivalents. “This would help in both unlocking significant amounts of housing development and delivering against other environmental priorities. These significant benefits can be realised with a targeted and proportionate approach. This would aid in reducing phosphorus deposition to a level that enables favourable status to be achieved, help meet other government targets on the environment, and the delivery of new homes to restart.”

Restoring rivers to good Ecological status is a complex challenge requiring cross-sector collaboration. The Environment Agency says: “There are multiple influences on river water quality in England. To make significant improvements will require investment from the water and farming industries and individual behaviour changes. We must continue to tackle a legacy of Victorian drainage systems, historic lack of capital investment in agriculture, sewerage and road infrastructure, and insufficient maintenance of that infrastructure … The changing climate and growing population make targets harder to reach.”



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