Re-use of Site-won Material to Create a Wetland Environment for Migratory Birds, Grimsby
Shortlisted for Brownfield Awards Category 13: Best Biodiversity Enhancement
Re-use of Site-won Material to Create a Wetland Environment for Migratory Birds, Grimsby
This submission presents the beneficial re-use of site-won material from brownfield land to create a wetland environment for migratory birds. Brownfield land in the UK often has great potential to support resident and migratory birds, given the proximity of some of our key industrial zones to some of our most important ecological resources. AECOM helped our Client to provide real ecological value to an otherwise ecologically redundant site, utilising the sustainable re-use of soils to add value to the local and regional environment.
This project demonstrates how AECOM can use multi-disciplinary resources to provide real value for clients looking to extract natural capital from brownfield redevelopment. This case study showcases how AECOM were able to use their breadth of experience to not only enhance the biodiversity of a nationally important natural environment, they did so in a sustainable, cost-effective manner which was protective of sensitive receptors in the surrounding area.
Associated British Ports (ABP), acquired the former Huntsman Tioxide site in 2016. The site is located near Immingham, on the mouth of The Humber Estuary, which is a Site of Special Scientific Interest (SSSI), Special Area of Conservation (SAC), Ramsar Site and Special Protection Area (SPA). This area features significant natural resources but is also an economically important industrial area and port. ABP wished to use the site for the storage of vehicles for import and export and the planning permission granted for this specified that an ecological area should be created as part of the development.
Image 1 - View of the former Huntsman Tioxide site
The site was owned by Huntsman Tioxide Limited (Huntsman) until 2012, with the site used for the manufacture of titanium dioxide pigment since 1947.
Following the acquisition of the site, ABP sought planning permission for “Alterations to include new vehicular accesses, fencing and installation of lighting for the storage and distribution of vehicles associated with import/export activities at the Port of Grimsby”. AECOM supported ABP’s purchase of the site and the submission of the planning application with several phases of ground investigation and post-investigation monitoring of groundwater and surface water. One of the planning conditions imposed was that the primary scheme could not be completed until ecological works were completed to provide an environment for migratory birds. As part of this process, a pond area was to be constructed to create an appropriate environment for birds. AECOM assisted ABP by designing and enabling this scheme, thereby enhancing the value of the area for nature and releasing the potential of the remainder of the site for industrial use. The works were completed in September 2020.
Exemplary best practice, cost effectiveness, and sustainability
To enable these ecological enhancement works to be completed in the most cost effective and sustainable manner possible, AECOM developed a Materials Management Plan (MMP) in line with the processes described in the CL:AIRE Definition of Waste: Development Industry Code of Practice (DoWCoP). This involved utilising material from different parts of the site to create a habitat which was robustly constructed and would not generate any unacceptable risks to surrounding receptors. Material would be taken from stockpiles within the mitigation area (known as Phase 2) to create bunds, lined with clay taken from adjacent on-site borrow pits, and covered with topsoil from the Sports Field part of the site. With this design, no imported material was required, and the development of the ecological area was as sustainable as possible. The extraction and haulage of raw materials was avoided, thus minimising the environmental impact of the work, and providing the economic benefit of re-using site-won material.
AECOM developed the MMP with the understanding that the redistribution of material from brownfield land in close proximity to such a sensitive receptor as the Humber meant that careful management of the process was needed. AECOM undertook detailed quantitative risk assessments in accordance with the Environment Agency’s Land Contaminated Risk Management (LCRM) guidance and calculated Site-Specific Acceptance Criteria (SSAC) that governed the acceptability of material for re-use. These were designed to ensure that the soils used did not pose an unacceptable risk to ecological and controlled waters receptors. AECOM undertook additional sampling of the excavated and stockpiled material and provided specifications for the contractors undertaking the work to ensure that samples were also taken upon placement for the purposes of validation. All data was compared to the SSAC and compiled for presentation in the final MMP.
Image 2 – design schematic of the wetland enhancement area (enlarged copy appended)
Compliance with legislation, codes and guidance and adherence to diversity practice
The work was undertaken in line with the requirements of the CL:AIRE DoWCoP. The work was determined to be “Route B) Design Statement” which is used where contamination is not suspected. In line with the guidance of the DoWCoP, AECOM provided the following to the client:
A design statement;
Details of all parties that will be involved with the implementation of the MMP;
A description and quantities of the materials in terms of potential re-use;
The specification for use of materials against which the proposed materials will be assessed;
Details of where and how the materials will be stored;
Details of the intended final destination of the materials;
Details of how the materials are to be tracked;
Contingency arrangements; and
Details of the verification plan.
An MMP form was obtained from the CL:AIRE website, completed and reviewed by a Qualified Person under the scheme. Care was taken to ensure that the Qualified Person submitting the MMP declaration was “arms length” from the project in order to protect the integrity of the process.
The DoWCoP is underpinned by UK guidance and regulations on waste and land conditions; primarily the UK government guidance on managing land contamination Land Contamination: Risk Management (LCRM), British Standard BS10175 “The Investigation of Potentially Contaminated Land” and The Waste Framework Directive.
The driver for the establishment of the bird mitigation area was the Conservation of Habitats and Species Regulations 2017 and saved policies GEN1 and NH1 from the now superseded North East Lincolnshire Local Plan and Policies 6 and 40 of the since adopted North East Lincolnshire Local Plan 2016.
Effective public/stakeholder engagement
A number of stakeholders were engaged in the execution of the project. North East Lincolnshire Council were consulted at all stages of development on both the ecological and land contamination requirements of the project. Natural England were consulted in the design of the bird mitigation area and in ensuring that the development did not impact the Humber SSSI, SAC, SPA and Ramsar designations. AECOM were able to successfully maintain these relationships through the lifecycle of the project and ensure that stakeholder requirements were successfully incorporated into the project.
Real environmental/economic/social benefit
The development has created an important habitat for feeding/ roosting curlew (and other high tide roosting birds relevant to the Humber SPA designation) and in turn helped to ensure that development is compliant with the Conservation of Habitats and Species Regulations 2010; specifically in respect of maintaining sufficient high tide roost areas for wintering/ passage birds that are functionally linked to the Humber Estuary SPA/Ramsar. In addition, it also creates additional habitat for water voles which have been noted in ecological studies of the site. This enhances an already important area for a number of species and therefore demonstrates real environmental benefit.
Image 3 – photograph of Sea wall (northern site boundary) with the Humber Estuary beyond.
A robust, sustainable and defensible solution
AECOM has provided a robust, cost-effective, sustainable and defensible solution that allowed a client’s development to proceed and also created tangible benefit for an important ecological system. We were able to find practical solutions to an ecological enhancement condition placed on the development, ensuring that the development could proceed successfully, on budget and within the timescales required by the client to meet their operational needs, while also benefiting local ecological systems.
Demonstration of respect for local ecosystems in a brownfield project, with long term planning to enhance biodiversity and amenity value
ABP’s recent news article on this work can be found here Associated British Ports | Curlew flock to new ABP mitigation site in Grimsby (abports.co.uk) and states:
Curlews, a species of wading bird, which has become one of the UK’s most important conservation priorities, have been making good use of mitigation land created by Associated British Ports (ABP) in Grimsby.
The Curlew breeding population has been declining in the UK for many years. Globally their breeding ground productivity has also been in decline, meaning their IUCN Red List status, a critical indicator of the health of the world’s biodiversity, is ‘near threatened’. The decline is thought to be a result of breeding habitat loss, predation, climate change, and a combination of these issues.
The five hectare site was completed last summer. It was required as part of the planning permission for the Grimsby Automotive Terminal, which is on the site of the former Huntsman Tioxide factory works.
Ecologists have reported excellent numbers of wading birds using the site. On a recent count, 225 Curlews, 153 Redshanks and 13 Dunlins were recorded. The area provides many benefits to waders, which feed on invertebrates within the mud and roost during high water periods, reducing the need to fly longer distances, saving valuable energy.
Ecologist, Richard Baines, from Wold Ecology, who has been monitoring the site said: “ABP’s investment in this expertly designed scheme, has certainly paid off, with an impressive result of wading birds using the area to feed and roost within.”
ABP Humber Director, Simon Bird, said: “ABP is committed to ensure that its port related activities and developments are carefully considered. It is pleasing to hear that the mitigation area is working as we expected, attracting many species of wading birds that use the Humber Estuary. We look forward to seeing the area go from strength to strength.”
The ecological enhancement work completed at this brownfield site has both enabled the land to be repurposed for beneficial re-use that supports the local economy as part of the port development, and resulted in a wetland area that should provide long-term beneficial habitat for wading birds.
Image 4 – enlarged image of design schematic of the wetland enhancement area