Reducing nitrates in the Solent

Reducing nitrates in the Solent

Southern marsh orchid © Lukas Steigerwald

A nature-based solution to the Solent nitrates issue

Decades of pollution from wastewater, urban runoff and agricultural discharges have caused the Solent to reach crisis point.

Read our response to the Solent nitrates issue

Read our blog: Reducing nitrates in the Solent 

Land at IoW Donkey Sanctuary, restored as part of Down to the Coast

Land at the Isle of Wight Donkey Sanctuary, restored as part of Down to the Coast © Lianne de Mello

Nitrates polluting the Solent

The high input levels of nitrogen and phosphorus to the Solent’s water environment are causing eutrophication. The resulting dense mats of green algae are impacting negatively on the area’s protected habitats and bird species. Algal mats covering the mudflats stop oxygen reaching the animals in the sediment and cause mass mortality, especially in hot weather. Algae also forms a barrier to many birds which rely on probing the mud or picking off tiny invertebrates from its surface. These mats can also smother some of our most threatened habitats: seagrass beds and saltmarshes, choking them to death and risking erosion.

Barton meadows © Martin de Retuerto

The impact on development

These nutrient inputs are caused mostly by wastewater and diffuse sources from existing housing and agricultural runoff.

The granting of planning permissions across parts of South Hampshire and the Isle of Wight has been temporarily suspended due to Natural England's decision to halt any development which could contribute to nitrate pollution in the Solent. 

This is good news as it recognises that our environment cannot continue to be damaged indefinitely.  However, it is only causing a delay to development. There is a broad suite of mitigation measures being developed by various organisations including water companies and local authorities as well as private landowners. These include agricultural land being taken out of intensive use, improvements to wastewater treatment works and on-site wetland construction. Once these are in place, development will restart.

The Wildlife Trust's nitrate reduction programme

Our programme, in simple terms, will provide a means of mitigating and reducing the nitrate impact of planned housing as well as creating new habitats for wildlife.

Our local seas are being suffocated by untenable levels of pollution and we have to find ways of reducing the levels of nitrates entering the Solent.  By taking the most polluting land and re-wilding it, not only are we relieving the pressure on our marine environment, but we will also create wonderful wildlife-rich habitat, reducing pollution, capturing carbon and helping nature to recover.  We must now ensure that we are creating great places for both people and wildlife to live and thrive.
Debbie Tann, Chief Executive
Hampshire & Isle of Wight Wildlife Trust

This nature-based solution works by acquiring intensively managed farmland in certain locations which is currently releasing nutrients into the Solent, and rewilding it, returning it to natural habitats, such as traditionally grazed meadows, wetlands, or woodlands. Our solution will reduce nitrogen inputs from farming to mitigate and reduce the additional inputs into the Solent arising from new houses – and create new nature reserves to benefit wildlife.

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There are a range of mitigation schemes coming forward and so the Wildlife Trust’s scheme is not the only option that local authorities or developers have. Whether the Trust or another body provides the mitigation, the planned houses will be built.

Our aim is to deliver a better mitigation option, one that delivers additional wildlife and pollution reduction benefits and transforms intensive agricultural land into nature reserves that are safeguarded for ever. There is more information in this paper, explaining exactly how it will work.

This scheme is only for developments that have met all other planning requirements, such as the habitats regulations and biodiversity protections.  By working constructively with local authorities, Natural England and developers, the Trust can shape development that is better for nature and set the bar higher so we see net gain for wildlife rather than net loss. 

Our ethical principles

We are clear that any mitigation we deliver must be in line with our ethical principles. The Trust will only provide nitrate mitigation for developments that have satisfied all other planning and legal requirements, particularly those relating to biodiversity. The planning process requires all developments to demonstrate that their proposals will not result in unacceptable impacts to existing important biodiversity. We have already refused to provide mitigation for developments which we have an objection to.

Where possible we will give preference to smaller developments, and to those who agree to incorporate wildlife gains into their plans, including contributing positively to the local nature recovery network.

We are committed to working positively with developers wherever possible to find ways of incorporating wildlife benefits into proposals. We feel it is important that we retain the ultimate decision whether to be involved in, or provide mitigation for, any particular project.

Frequently Asked Questions

Where are the locations of the mitigation sites?

Mitigation sites map

The Trust has recently acquired Little Duxmore Farm on the Isle of Wight, which is acting as a pilot, allowing us to demonstrate proof of concept and to test out how the scheme might be rolled out more widely.

The site, a former arable farm, discharges into the Wootton Creek which in turn runs into the Solent. As the Trust restores it to natural wildlife habitats, this will directly reduce nitrate inputs into the Solent.

Solent nitrates, fluvial catchments

Is it right for developments in south Hampshire to be mitigated elsewhere?

It seems strange to some that a farm on the Isle of Wight farm can provide mitigation for houses on the south coast of Hampshire, and it seems unfair that some areas will benefit from new wildlife sites whilst others will not.

This is a fair criticism of the scheme which is designed to deal with nitrate pollution of the Solent only, and not other issues such as local biodiversity or provision of greenspace.

The suitability of mitigation sites is based on their ability to remove nitrates from the right part of the Solent ecosystem, in the timescale required. Nutrient budgets are based on hydrological modelling, taking into account nutrient loading from different land use types and the way in which runoff moves through catchments, recognising the variety of soil types and how water travels through surface water and groundwater and ultimately into the Solent. Because of this, it means that it is not always possible to secure appropriate farmland close to where new houses are being built.

Looking ahead, the Trust is aiming to acquire a number of similar nitrate mitigation sites across the Solent sub-region if possible. We would like to secure at least one strategic land acquisition in each sub-catchment area so that permanent environmental and wildlife benefits are delivered across the whole area.

Why is the Wildlife Trust involved?

Some people are questioning why the Wildlife Trust is involved, as it may seem counterintuitive that we should work constructively with planners and developers on positive solutions rather than trying to stop development.

In fact, the Trust has worked with the planning system for decades, and we continue to invest a significant amount of time in influencing planning at a strategic level, both within our two counties and nationally. We continue to challenge the most damaging developments and over the years have won a few important campaigns.

We have made some good progress in changing policy too, for example, many of the planning policies and regulations that force developments to take wildlife into account, and for mitigation to be secured, have come about due to campaigning by ourselves and others. Indeed, many of today’s well-loved nature reserves (such as Blashford Lakes, Fishlake Meadows, Swanwick Lakes, Testwood Lakes and Barton Meadows) were secured as forms of mitigation through the planning system.

However, it is also true that we have little or no influence on housing numbers or broad locations which are set by central government. Indeed, when we recently analysed our development control work over several years (i.e. objecting to planning applications) we found we were rarely successful as decisions had already been made.

While the nitrates issue has undoubtedly delayed house building in the area, solutions are now becoming available. The development of sites allocated within local plans will take place with or without the Wildlife Trust’s involvement.

In choosing to be involved, we aim to provide a better mitigation option – demonstrating that protecting and improving the environment is essential to a strong economy and that solutions are not only possible but can deliver additional benefits for wildlife and people as well.

Is there a risk of environmental protections being weakened?

The delays to development in south Hampshire have become national news and have resulted in significant and growing political pressure against nature and environmental legislation which is being held up as a barrier to economic progress. There is no doubt the government is frustrated with the Solent nitrates ‘issue’. In the local area, Natural England has been under immense pressure for at least a year to find a solution and this has led to the various mitigation schemes, some by commercial organisations, coming forward.

The demand for economic growth, especially post Covid-19, poses real risks to the environment. We saw a glimpse of the likely direction of travel in Prime Minister Boris Johnson’s ‘Build, Build, Build’ speech on 30th June in which the prospect of diluting wildlife and environmental protections to accelerate house building was clearly stated. The EU Habitats Directive and many other important European laws have not yet been enshrined in domestic legislation for when the UK leaves the EU in January 2021. Post Brexit the government will be free to introduce legislation that will dilute or remove the protections currently in place.

If this happens, the impact of nitrates will be unmitigated and our most important wildlife sites will lose their protection. No further sites will be acquired for wildlife through this route. There will be no requirement for any mitigation for the Solent and the developments currently held up will restart straight away with no investment in cleaning up pollution or helping wildlife. Further unrestrained development of our coastal landscape and damage to the environment will be even more likely.

The Environment Minister George Eustice has made it clear for some time that there will be a reform of planning and environmental protection rules. More details of proposed planning reforms have recently been announced by the Housing Minister Robert Jenrick: the-planning-system.

We, with other NGOs continue to campaign and lobby against any changes like these where they will be detrimental to the natural environment.

But we are also positioning nature-based solutions as a positive answer so that those driving economic growth can start to appreciate the vital role of investing in nature to support society and a sustainable economy.

Will mitigation mean that even more houses will be built?

Housing numbers are set by government targets and the local plan. House building has been held up whilst nitrate mitigation solutions are found, and the provision of mitigation will allow planning permissions to proceed that have been held up temporarily. This will not, in itself, lead to additional houses being built.

What is the effectiveness of mitigation and ‘nutrient neutrality’?

There have been some criticisms that achieving neutrality alone will not result in significant improvements to the Solent’s important habitats.  We agree, and there are a number of ways in which we are working to reduce the impact of nutrient pollution overall.  

The concept of nitrate mitigation is complex and there are various options to achieve this including the creation of interceptor wetlands and appropriate land being taken out of high nitrogen uses such as intensive farming.

There is a publicly available document which explains the methodology used by Natural England to calculate the nitrogen budget of different types of developments and the basis on which mitigation will work. The calculations are based on the best available evidence on nutrient loading from different land use types and the way in which runoff moves through various parts of the different catchments, recognising the variety of soil types and how water travels through surface water and groundwater and ultimately into the Solent.

The Natural England methodology includes a precautionary buffer of approximately 20% to recognise that there is an element of risk in relation to the exact amount of nutrients coming from developments if the actual occupancy rates and use of water by individuals differ from the assumptions used.  The calculations are based on the concept of nitrate balancing to achieve nutrient neutrality as this is the legal requirement for planning.  The Trust is comfortable that the methodology and approach satisfy the required legal tests.

In addition, there are other initiatives in place, such as Catchment Sensitive Farming, which help to curb excessive nutrient loads from agriculture more broadly. The Trust is actively involved in influencing the new Agriculture Bill and we campaign with other NGOs for the continued reduction of chemicals and artificial fertilisers in farming. We have an active and successful Farm Advice programme which works directly with many farms and large estates to reduce their impact on the environment. We also influence water policy and have campaigned for more investment from water companies in better wastewater treatment. 

We continue to push for more to be done for nature, and we also aim to demonstrate what we mean by delivering high quality solutions and seeking to raising the bar overall. The Wildlife Trust’s nutrient mitigation scheme is therefore designed to be rather different from the other mitigation measures being put forward.

Our scheme is the only one which will deliver significant additional benefits for wildlife as any mitigation sites delivered by us will be transformed into wildlife rich spaces and nature reserves which will be safeguarded in perpetuity. In addition, we aim to incorporate additional headroom into our calculations to provide more capacity for nutrient reduction where possible. Each mitigation site is considered on a case by case basis, and the nitrate reduction potential depends on several factors as described above. However, we will always strive to achieve more than neutrality as this is clearly needed to improve the quality of the Solent’s habitats.

What are the calculations and financial details?

It is Natural England’s job to determine the final exact figure for the kilograms of nitrogen that each mitigation site will deliver, using the published methodology mentioned above. This requires precise mapping (to exclude any hedgerows or woodland for example) and 5 years of agricultural cropping records for each site acquired.

As an example, Natural England has determined that the Trust’s plans for rewilding Little Duxmore Farm will remove 848 kgs of nitrogen per year from the Solent ecosystem. The Trust has agreed to take off a further amount to provide headroom and thus deliver not only the mitigation amount but a net reduction in pollution. Little Duxmore Farm will therefore provide 800 nitrate credits – providing mitigation for approximately 400 houses, contributing towards nitrate reductions and delivering additional wildlife benefits.

We have to balance the costs of acquiring and managing the site with the affordability of the credits, but on this site 5% headroom can be accommodated. Each site is considered on a case by case basis and the amount of mitigation and headroom will depend not only on affordability but also the hydrological monitoring and nitrate budget calculations for each situation.

The 800 credits from Little Duxmore Farm will be sold for c.£2,500 each, providing a fund of £2,000,000 which will cover legal fees, repay the loan for the purchase of the land itself, and provide a long-term management fund ‘in perpetuity’. This is explained further below.

As a charity the Trust must show, and our auditors must be satisfied, that we have made provision to cover the costs and liabilities of our ongoing commitments, and so the money will be placed in a designated fund for this purpose. Drawing on this fund each year is overseen by the Board of Trustees.

The Trust is committed to Little Duxmore Farm as a nature reserve and the site is already recovering from decades of intensive farming after only a few months with wildlife bouncing back. We will undertake a programme of ecological monitoring to establish and communicate the wildlife gains as we rewild the site over the coming years. If the nitrates scheme collapses for any reason, we will seek alternative finance for this particular acquisition, but no more sites will be secured through this route.

What does ‘in perpetuity’ actually mean?

In planning terms ‘in perpetuity’ is considered to be between 80 years and 125 years, and this is normally set by the local planning authority. For Little Duxmore Farm the period has been set at 125 years. This figure is then used to establish the ‘commuted sum’ required to create an adequate long-term management fund. The sums are based on how much the land costs to buy, capital works required, and how much is needed each year to manage the site. The Trust is a non-profit organisation and so the sum is based on what is realistically needed to manage and protect the land.

As a charity the freehold land we own becomes a heritage asset and cannot be disposed of without a complex legal process. In our 60-year history we have never disposed of a heritage asset. The Trust is committed to managing Little Duxmore in line with our charitable objectives (for wildlife, education and science) beyond the 125-year period and this is also written into the legal agreement we will be entering into with the local authorities. So, our sites will effectively be safeguarded for ever.

How does this fit with the Wildlife Trust’s mission?

Some people have questioned if the Trust is acting in line with our charitable objectives and strategic plan. We have carefully considered whether offering a mitigation scheme to reduce nitrate pollution in the Solent is the right thing to be doing, and we have discussed and developed our approach over several months in consultation with the charity’s Board of Trustees, legal advisors and auditors, senior staff and our in-house ecologists, as well as Natural England and the local authorities.

We are firmly of the view that delivering nitrate reduction together with the wider benefits described above as part of a range of nature-based solutions is entirely consistent with our mission to create a wilder Hampshire and Isle of Wight.

The Trust recognises the urgency of the ecological crisis and we have recently shaped a new strategy in response. This was developed over 18 months through a series of events and consultations with our staff, Trustees, members, supporters and partners – starting with the launch of our Wilder discussion document in 2018 and leading to the launch of our Wilder 2030 strategy in October 2019. For wildlife to recover, we are clear that at least 30% of our land and sea must be made wilder by 2030. The concept of a nature recovery network is key to achieving this vision.

To achieve this, we need to use all the mechanisms available to us, including working with farmers, private landowners, schools, community groups, businesses, public bodies, government agencies, planners and developers. The nature recovery network does not exclude anyone, and we have community engagement and education programmes in place to encourage people to make space for wildlife in their gardens, schools, parks and streets.

We know that intensive agriculture is by far the main cause of wildlife decline, and with farmland covering almost 80% of our land surface it is vital that we work proactively to change this. Our so-called ‘green and pleasant land’ is often devoid of wildlife and so working with farmers and landowners to incorporate wildlife into their businesses, influencing agriculture policy, and creating new large wild areas for nature in the countryside are all high priorities for us.

We also know that developments can, if designed well, result in an overall net gain for wildlife, and we are keen to demonstrate what good development looks like through our new Building with Nature service. Developed areas still represent less than 10% of the total area of Hampshire and Isle of Wight and whilst we appreciate the failings of the planning system to provide adequate green infrastructure for people, we are keen to influence the design of developments where we can so that they achieve positive outcomes.

And as part of our collective responsibility to tackle climate change and our journey to net zero greenhouse gas emissions, we will be offering ways in which carbon can be removed from the atmosphere through restoring natural habitats – another nature-based solution.

Is the Wildlife Trust facilitating development?

Our priority is nature’s recovery. We recognise that more homes may be needed but we want to make sure that development is sustainable and gives back to nature more than it takes away - every building project should deliver ambitious ‘net gain’ for nature.  

We are willing to work with local authorities and developers, as long as they can demonstrate clearly that they are meeting their regulatory requirements with regards to biodiversity.   

We will only accept funds for nitrate mitigation where all other planning issues have been resolved. We have turned down proposals brought to us by developers that do not properly support nature’s recovery.  

By accepting a site into our scheme, we are not supporting the planned development; our goal is to reduce the nitrates polluting the Solent and damaging internationally important habitats. In addition to this we will be creating new areas for wildlife to thrive - aiming to reverse the declines in wildlife we have seen in recent decades.  

Throughout this we will continue to challenge both policy makers and house builders to secure the best outcomes for wildlife and people. 

What might happen if we do nothing?

Several alternative schemes to offset nitrates are now coming forward - economic pressures are forcing solutions to be found.  The Wildlife Trust's scheme is the only one that puts the restoration of wildlife at its core.  

Other options to address the issue either will not lead to any wildlife gains or, if an alternative solution cannot be found, the Government could reduce the legal protection afforded to our internationally important wildlife sites. These protections are underpinned by European Law.  After 1st January 2021 the UK Government will be able to amend these laws and we fear that the prohibition on development around the Solent will be used as a reason to dilute protections across all internationally important sites. 

Will this scheme be bad for farmers and food production?

The nitrates scheme will target lower quality farmland that has less agricultural potential than other areas - often the reason why nitrate pollution is an issue in the first place.  This represents a very small fragment of available farmland in the area and will not have a negative impact on farming and food production.