Overview
Establishing and characterising the environmental baseline conditions is a critical step in the EIA process and is achieved through gathering information from a number of sources. Initially, desk-based resources are used to establish key aspects of the baseline. Where there are gaps in information, or more detailed or accurate information is necessary, site visits and surveys are undertaken to ensure precise and robust data is obtained.
Surveys are conducted throughout the year and, depending on the type of survey, sometimes multiple times to ensure the gathered data are robust. Surveys can be either intrusive (requiring excavation of boreholes and trenches, for example) or non-intrusive, but most require landowner access to be agreed.
Approximately 6,450 surveys and site visits have been completed since 2020 to support the development of the proposals and inform the ongoing EIA process. Further surveys have taken place during 2024 and will continue through 2025.
Desk-based information
Desk-based information can be gathered from a wide-range of sources. This includes publicly available information from local authorities and other government agencies, such as data relating to air quality management areas, local ecological and historical records, and protected sites. Understanding the location of sensitive environmental features is essential to the application of the Mitigation Hierarchy and is fundamental as a first stage in informing what further study is required.
Other information that is gathered includes high-resolution satellite imagery, geological data and topography models. This information is used for a number of topics and is sometimes as the basis for detailed modelling, such as for noise or visibility impacts.
EWR Co has also worked with other projects, such as National Highways’ A428 Black Cat to Caxton Gibbet improvements scheme (with the new A421 dual carriageway currently under construction) and the Greater Cambridge Partnership’s Cambourne to Cambridge guided busway and active travel projects, to share information gathered from surveys and studies undertaken.
People-focused surveys
There are several EIA topics that need information collected through surveys to enable an understanding of the project and its relationship to the people living and working along the route and surrounding area.
As well as having collected existing air quality data from local authorities, NOx monitoring to understand the baseline air quality conditions has been undertaken at approximately 65 locations. The results will be analysed and fed into impact modelling presented in the ES.
For traffic and transport, surveys include traffic count surveys (both automatic and manual) to record road use, car parking surveys of current patronage, and monitoring of usage of public rights of way (PRoW) to inform impact assessment and diversion needs. So far approximately 1080 surveys relating to traffic have been completed across the route.
Baseline noise surveys are used to establish the existing noise levels and around 60 noise surveys have been completed to date. Some background vibration monitoring may also be needed for certain sensitive users along the route.
Farm business interviews are currently underway to understand how the project and its construction could impact farming practices. Both soil resource surveys and Agricultural Land Classification surveys will be carried out to understand soil types and the quality of farmland affected by the project. Much of this can rely on existing survey data undertaken for other projects, with further surveys planned.
Nature-focused surveys
Surveys of ecological receptors are required to characterise the status and distribution of habitats and certain species or groups of animals. These include aquatic surveys, habitat mapping, and fauna surveys for bats, badgers, otters and others. Bird surveys record species present, and walkovers inspect for insects and other terrestrial invertebrates and veteran trees will be recorded across the route.
Since 2020 approximately 4,500 ecological surveys have been carried out with further surveys planned. These surveys are continuing to provide additional data on the likely presence and distribution of protected and notable habitats and species. As more information becomes available, and as the project design and construction phasing plans develop, mitigation plans will evolve, following the Mitigation Hierarchy.
Water and flood risk surveys will be used to identify groundwater dependent terrestrial ecosystems and identify private water supplies across the study area, whilst Water Framework Directive (WFD) surveys will consider the river morphology, and river and ditch conditions for watercourses across the route. The majority of these surveys will be undertaken in 2024 and 2025.
In addition, the project will undertake ground investigation to include contamination testing of soils, groundwater and surface water to confirm the ground conditions, groundwater regime and any surface water groundwater interaction.
Landscape and historic environment surveys
Landscape surveys are required to help understand the character of the landscape or townscape, identifying key features that contribute to character. Photographs are used to illustrate the landscape and visual baseline assessment and to establish the likely visibility of the project. The surveys will be informed by desk-based research using published landscape character assessment, mapping and aerial photography. Since 2020, around 900 surveys have been completed.
The majority of locations selected for the field surveys are on PRoW and other publicly accessible places such as public roads, footways, car parks and open space. In inaccessible areas where access cannot be agreed with the landowner, the land or premises are private, or there are no nearby suitable PRoW, professional judgement is used to describe the likely landscape/townscape character of the area or the likely view from these locations.
For the historic environment, an evaluation phase has started to establish an enhanced understanding of the historic character and development along the route. The evaluation phase will include a range of desk-based investigation and analysis and field surveys. The results of archaeological, geoarchaeological, historic landscape, and built environment surveys will be brought together to develop a fuller understanding of the historic environment as a whole and allow for a combined approach to the assessment.
A range of field surveys supported by desk-based investigation will be undertaken to understand the potential for surviving archaeology and how important that archaeology is likely to be in contributing to wider knowledge of the area. Some surveys have already started, with geophysics and remote sensing surveys in progress in some areas. Following these surveys and additional desk-based research, a suite of targeted intrusive surveys, including trial trenching, will be developed in collaboration with stakeholders to allow for a detailed and robust baseline to inform the assessment and design development.
Geoarchaeological character will be investigated by using existing borehole data and data gained from ground investigation surveys carried out for the project to develop a deposit model.
Surveys will be undertaken to understand the historic environment along the route. These surveys will be informed by desk-based research using online and archive materials. Walkover surveys will also be carried out to identify key heritage assets, both designated and non-designated, and to get an understanding of the varied historic character along the route and its level of survival.
The assessment is continuing to investigate and understand the historic development of the area crossed by the project to inform the EIA work and to help manage the historic and cultural environment as part of design and mitigation work. The approach to this assessment is set out in the Approach to Historic Environment factsheet.
Modelling
Transport modelling
The East West Rail Strategic Highway Model (EWRSHM) has been developed and used as an interim tool to assess traffic impacts. The preliminary results are presented in the Transport Update Report(TUR). The model has provided information on baseline and future traffic flows, providing predictions on how these could change with the introduction of the project construction traffic and then consequently as a result of the operation of the new East West Rail services. Further information is available in the TUR.
Following this consultation additional transport modelling will be undertaken using a new and bespoke corridor-wide model, before the proposals for the project are finalised, and the results presented in a Transport Assessment (TA) to accompany the DCO application.
Flood modelling
Flood models are developed to reflect baseline conditions as closely as possible before potential impacts of new infrastructure can be modelled and the effects understood, which can then be used to inform approach to avoid impacts, manage impacts or mitigate them.
Initial development of existing baseline flood models was undertaken in 2021 to support earlier stages of the project development. These addressed 11 watercourses crossed by the proposed new alignment between Bedford and Cambridge.
Further development of these models, as well as others between Oxford and Bedford, is underway and will utilise existing Environment Agency models, new survey data and models and models developed for the new A421 dual carriageway.
As the project design develops, further modelling will be undertaken where required to inform flood risk assessments that support the project. This modelling will be undertaken in consultation with the Environment Agency (responsible for flood risk management activities on Main Rivers), Lead Local Flood Authorities (responsible for managing local flood risks from surface water, ordinary watercourses and groundwater) and other risk management authorities as appropriate.
