Soils

Policy POSP3: Soils

  1. Proposals shall:
    1. Protect the best and most versatile agricultural land, defined as Grades 1, 2 and 3a of the Agricultural Land Classification (See map in supporting text);
    2. Address decontamination where needed in order to improve quality;
    3. Re-use topsoil locally;
    4. Principally, leave soils that are carbon sinks in situ;
    5. Manage soils in a sustainable way during construction;
    6. Take particular care in the transportation and disposal of soil during development to
      prevent possible movement of invasive species; and
    7. Address soil erosion and possible contamination of the water environment.
  2. Where significant development of any grade of agricultural land is demonstrated to be necessary, detailed field surveys should be undertaken and proposals should seek to use areas of poorer quality land in preference to that of higher quality.
  3. The Authority will require all applications for development to include realistic proposals to demonstrate that soil resources were protected and used sustainably in line with accepted best practice, including the DEFRA safeguarding soils strategy.

Reasoned Justification

The NPPF seeks the protection and enhancement of soils. The NPPF2023 also says at footnote 62, ‘Where significant development of agricultural land is demonstrated to be necessary, areas of poorer quality land should be preferred to those of a higher quality’.

The NPPG identifies soils as: an essential natural capital asset that provides important ecosystem services – for instance, as a growing medium for food, timber and other crops, as a store for carbon and water, as a reservoir of biodiversity and as a buffer against pollution.

The peat and alluvial gley soils on the grass marshes are rich in carbon (see next policy relating to peat specifically).

Best and most versatile agricultural land

The following map shows the best and most versatile agricultural land in the Broads, defined as Grades 1, 2 and 3a of the Agricultural Land Classification[48]. Development of the best and most versatile agricultural land will not normally be permitted unless it can be demonstrated that the need for the development clearly outweighs the need to protect such land in the long term, or in the case of temporary/potentially reversible development that the land would be reinstated to its pre-working quality, and there are no suitable alternative sites on previously developed (brownfield) or lower quality land. Where a development would result in a sizeable area being lost (and there is no existing detailed soil information available), then a soil quality survey may need to be completed.

Map showing Agricultural Land Classification

Contaminated land

Soil pollution can arise from different sources including agricultural activities and fuel storage. Where development is proposed on land that could be contaminated, a site investigation will usually be required.

Non-native invasive species

The Broads has a number of non-native invasive plant and invertebrate species which are easily transferable between sites via machinery, soil and damp equipment. These species can alter entire ecosystems by displacing or outcompeting local species, spreading disease, changing the ecology, and physically clogging the waterways.  Any proposal for development on or near water, or on land with record(s) of invasive species present should include appropriate biosecurity measures:

  • ‘Clean, Check, Dry’ machinery, equipment and clothing before moving between sites – for more information see www.nonnativespecies.org/checkcleandry
  • Avoid transfer of vegetation or viable seeds or propagules in topsoil or other material. If possible, reuse soil on the same site.
  • Avoid importing topsoil which is unscreened.

Soil erosion

Soils are susceptible to erosion which can pollute ditches and waterbodies via sedimentation or addition of nutrient contained in the soil, and the Authority works actively with landowners to address this. The sediment and nutrient released into water can smother vegetation and invertebrate life, and result in algal blooms which cause further damage to the ecology. Mitigation strategies should include:

  • Leaving an appropriately sized buffer strip (3-5m wide) of vegetation between work site and surrounding ditch network.  If necessary, use appropriate ground protection system to keep machinery disturbance of vegetation to a minimum in the buffer area.
  • Rapidly re-establishing native vegetation cover over exposed and disturbed ground.  Where it is necessary to store soil, keep it covered to avoid erosion.
  • Use of sediment traps, such as earth bunds or via creation of new ponds to slow the flow of water and prevent sediment reaching ditches.

Soil runoff can carry sediment and nutrients into the local watercourses where they can reduce water quality, smother fish spawning grounds, and increase the risk of local flooding. Soil runoff can come from many sectors including construction sites, eroded rural roads and agriculture through heavy rainfall on compacted soils or cropped fields which are not properly managed. Advice is available for the agricultural sector on minimising runoff and managing soils. Construction sites shall be required through the planning process to take adequate steps to minimise soil runoff.

Resources

As part of the Government’s ‘Safeguarding our Soils’ strategy[49], Defra has published a code of practice on the sustainable use of soils on construction sites[50], which may be helpful in development design and setting planning conditions.

The Guide to assessing development proposals on agricultural land says to use the post 1988 ALC Magic map and detailed site survey reports to help you assess whether a development proposal is likely to affect BMV agricultural land. If no suitable data exists, you may need to carry out a detailed survey to support your planning application.

Reasonable alternative options

No policy

The original policy, with no amendments.

Sustainability appraisal summary

The following is a summary of the assessment of the policy and alternative(s).

A: No policy. 0 positives. 0 negatives. 5 ?

B: Keep original policy. 4 positives. 0 negatives. 0 ? Overall, positive.

C: Preferred Option - amend policy. 4 positives. 0 negatives. 0 ? Overall, positive.

How has the existing policy been used since adoption in May 2019?

According to recent Annual Monitoring Reports, the policy has been used and applications have been determined in accordance with the policy.

Why has the alternative option been discounted?

The amended policy is preferred because it provides clarification and emphasises the properties and importance of soils.

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Policy PODM11: Peat soils

See map: Appendix 10: Location of peat soils

  1. Sites of peat[51] soils will be protected, enhanced, and preserved.
  2. There will be a presumption in favour of preservation in-situ for peat soils.
  3. Development resulting in the loss or deterioration of peat (an irreplaceable habitat) will be refused, unless there are wholly exceptional reasons (see supporting text), and a suitable compensation strategy exists, and it is demonstrated that:
    1. There is not a less harmful viable option; and
    2. The amount of harm has been reduced to the minimum possible; and
    3. An evaluation is submitted to assess the impact of the proposal in relation to palaeoenvironments, archaeology, biodiversity provision and carbon content; and
    4. Satisfactory provision is made for the evaluation, recording and interpretation of the peat before commencement of development; and
    5. The peat is disposed of in a way that will limit carbon loss to the atmosphere.
  4. Development that seeks to enhance biodiversity but may result in some peat removal will still need to demonstrate the criteria i) to v) and that the biodiversity benefit will outweigh carbon loss.
  5. Proposals to enhance peat and protect its qualities will be supported.

Reasoned Justification

Peat is an abundant soil typology in the Broads and an important asset. While there is a certain irony in protecting the peat soils in an area where the lakes originated from peat extraction, peat is a finite resource.

Ecosystem services

Peat has many qualities and provides many ecosystem services:

  • Climate change: The soils formed by the Broads wetland vegetation store 38.8 million tonnes of carbon[52] . Peat soils release previously stored carbon when they are dry. UK peats therefore represent both a threat and an opportunity with respect to greenhouse gas emissions. Correct management and restoration could lead to enhanced storage of carbon and other greenhouse gases in these soils, while mismanagement or neglect could lead to these carbon sinks becoming net sources of greenhouse gases.
  • Biodiversity: Peat soils support internationally important fen, fen meadow, wet woodland, and lake habitats. 75% of the remaining species-rich peat fen in lowland Britain is found in the Broads. Milk parsley, the food plant of the Swallowtail caterpillar, grows only on peat soils. Fen orchids have their UK stronghold in the Broads, so the peat soils are critical for the survival of this species. Other rare and important plant and invertebrate communities (collection of species) are supported by the peaty soils.
  • Archaeology: Historic England has identified the Broads as an area of exceptional waterlogged heritage. Because of the soil conditions in the Broads, there is great potential for archaeology to be well preserved, giving an insight into the past. Archaeology is discussed in more detail in the Heritage section of this Plan.
  • Palaeoenvironments: The peat has accumulated over time and thus incorporates a record of past climatic and environmental changes that can be reconstructed through, for example, the study of its stratigraphy and pollen content, leading to increased knowledge of the evolution of the landscape.
  • Water: Peaty soils help prevent flooding by absorbing and holding water like a sponge as well as filtering and purifying water. Peat can absorb large quantities of nutrient and other pollutants, although peat soils can under certain conditions release these chemicals back into the surrounding water.

How peat quality can be impacted

Land management that could impact on the quality of the peat soil includes land drainage, introduction of polluted water, burying the peat under hard surfaces or gardens, compacting peat and peat removal to change the land use.

Priority habitat. Irreplaceable habitat.

NPPF (2023) para 186c) says ‘development resulting in the loss or deterioration of irreplaceable habitats (such as ancient woodland and ancient or veteran trees) should be refused, unless there are wholly exceptional reasons63 and a suitable compensation strategy exists’.

Footnote 67 says ‘For example, infrastructure projects (including nationally significant infrastructure projects, orders under the Transport and Works Act and hybrid bills), where the public benefit would clearly outweigh the loss or deterioration of habitat’.

The NPPF glossary defines ‘irreplaceable habitats’ as ‘habitats which would be technically very difficult (or take a very significant time) to restore, recreate or replace once destroyed, considering their age, uniqueness, species diversity or rarity. They include ancient woodland, ancient and veteran trees, blanket bog, limestone pavement, sand dunes, salt marsh and lowland fen’.

Peat is not a habitat that can be recreated elsewhere as the deep soils take many thousands of years to form. Indeed, a site in Salford that formed part of Greater Manchester’s local spatial framework Places for Everyone was removed by Inspectors due to the development proposal’s public benefits not outweighing the loss of deterioration of peat[53].

The Authority therefore considers peat is an irreplaceable habitat and so the tests set out in the NPPF will need to be passed for development that negatively impacts peat to go ahead.

Lowland Fen

Lowland fen is a priority habitat under the UK Biodiversity Action Plan and the EU Habitats Directive because of the quality and diversity of species it supports. Lowland Fen is also classed as an ‘irreplaceable habitat’ in the NPPF. The JNCC[54] says ‘fens are peatlands which receive water and nutrients from the soil, rock and ground water as well as from rainfall: they are minerotrophic’.

Biodiversity enhancements schemes

On occasion, for nature conservation benefits, peat can be removed to create shallow turf ponds or scrapes (areas of temporary open water) on areas of fen or scrub habitat to maximise the biodiversity value and hold back succession to woodland habitat. The removal of peat can also be necessary for conservation management – for example, the most biodiverse areas of UK fen occur in areas where the turf has been stripped and vegetation subsequently grown back. This policy allows for such operations, provided they can justify the proposal against the criteria set out in the policy.

Excavation of peat as a mineral resource

The NPPF and NPPG mentions peat soils specifically in relation to its excavation as a mineral resource, rather than the issue in the Broads relating to impact due to groundworks from development and inappropriate land management.

If the public benefit of a scheme is proved to clearly outweigh the loss or deterioration of peat

The policy and NPPF seeks protection of peat soils through changes in the location of development in the first instance and then designing proposals to minimise disturbance to the qualities of the peat and the amount of peat removed. Development proposed on areas of peat would require justification for the need to site the development on peat, and subsequently a peat assessment that shows how efforts have been made to reduce adverse impacts on peat. Proposals that would result in removal of peat are required to assess the archaeological and paleoenvironmental potential of peat and make adequate recordings prior to removal.

To prevent the loss of carbon to the atmosphere that is sequestered in peat soils, disposal is of great importance. The Authority expects peat to be disposed of in a way that maintains the carbon capture properties. Peat needs to go somewhere where it can remain wet (and hence retain its function to lock up carbon and prevent it being released into the atmosphere) or potentially provide a seedbank (the potential for ancient peat to provide a viable seedbank may need to be evidenced) or be reused for local benefit (for example by boosting organic matter in degraded arable soils). When dry, peat changes its properties and oxidizes, so transfer to the receiving site would need to be immediate.

The Broads Authority have produced a guide to understanding and addressing the impact of new developments on peat soil. This Guide provides additional information to help applicants meet the requirements of the related peat policy. It seeks to reduce the amount of peat excavated, ensure the special qualities are addressed and ensure that any peat excavated it disposed of in a way to ensure stored carbon is not emitted into the atmosphere.

Reasonable alternative options

No policy

The original policy, with no amendments.

Sustainability appraisal summary

The following is a summary of the assessment of the policy and alternative(s).

A: No policy: 0 positives. 0 negatives. 3 ?

B: Keep original policy: 3 positives. 0 negatives. 0 ? Overall, positive.

C: Preferred Option - amend policy: 3 positives. 0 negatives. 0 ? Overall, positive.

How has the existing policy been used since adoption in May 2019?

According to recent Annual Monitoring Reports, the policy has been used and applications have been determined in accordance with the policy.

Why has the alternative option been discounted?

The amended policy is preferred because it provides clarification and makes the policy more consistent with the NPPF.

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