Enabling works and EIA

25th April 2013

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Richard Farmer, from Jacobs, talks about how the environment impact assessment (EIA) process influences enabling works and potential issues with the programming of ecological mitigation

Enabling works are the preparation of a site in readiness for the first stage of development. Examples include installing perimeter fencing, carrying out ground clearance, building access routes and putting up safety signage. Enabling works may also include preliminary construction work, such as groundworks. The result is a site that is ready and equipped for the main body of works to begin.

Enabling works are often the first activities on a site, so their completion is a critical period for the installation of environmental mitigation, particularly ecological mitigation.

Typical activities that might be undertaken during this period include the installation of tree protection fencing, fitting wildlife boxes and the translocation of protected species.

These activities have to be undertaken prior to commencement of the main works to ensure appropriate protection to the species or habitats concerned. Disturbing protected species or damaging their habitats is a criminal offence and can lead to fines of up to £5,000 per offence (for example, for each animal killed) and/or up to six months imprisonment.

EIA is the key tool for identifying all ecological constraints and ensuring that programming constraints (such as avoiding hibernation periods) are identified at an early stage.

An EIA should also identify when ecological mitigation is to be implemented, so it can be included in the construction programme and contract documents. This is particularly useful for large projects where multiple contractors are involved as a means of clearly defining who is responsible for the implementation of mitigation.

Construction programmes are often tightly scheduled with site costs increasing for every month a site is active. Enabling works must therefore be planned effectively to allow the main construction works to commence without restrictions.

Ecological constraints can restrict construction activities as some mitigation measures can only be implemented at particular times in the year to reduce the risk of ecological impacts. Many of the restriction periods are not in alignment, so careful consideration of the practicality of undertaking the work, in combination with the restrictions, is required.

For example, a construction project starting in January requires tree removal before the main works can be initiated. However, the only access is via a field which has been identified for great crested newt. The trees cannot be removed before the bird breeding season (March to August), but translocation of great crested newts from the access track is not possible until after the newt hibernation period (November to February).

In this instance the main construction works can not commence until September. This is because site access is required before felling can begin, so translocation exercises must be undertaken first, but they are restricted until March. And, once access is permitted, tree felling can only begin after the bird breeding season has ended in August.

This is a basic example and actual sites can be characterised by many other ecological constraints, such as populations of dormouse, bats and badgers, for example.

Key to ensuring the practicality of implementing the ecological mitigation prescribed in the EIA during the enabling works is the continued interaction between ecologists and design teams throughout the development of the EIA.

Early engagement of a contractor will ensure that the firm understands the constraints that will be imposed on it and will enable discussion of the practicality of the construction works and the detailed steps required to undertake a task.

An environmental action plan is a useful tool to highlight all of the ecological constraints in an EIA and the timings/responsibilities of when mitigation activities should be undertaken.

An added difficulty when trying to programme ecological mitigation arises from the fact that wildlife habits (such as hibernation periods and breeding seasons) are highly dependent on local weather conditions.

The EIA and contractor’s programme must also account for the potential risk to the project caused by delays to certain ecological mitigation works. This risk should be carefully communicated to all parties, as significant follow on effects could arise.

Key things to remember when undertaking EIAs in relation to the enabling works:

  • Continued liaison between the design team and ecologists reduces the risk of ecological constraints and programming restrictions impeding the works.
  • Early engagement with contractors may improve the programming of ecological mitigation during the works and outline any issues not already considered.
  • Ensure that the client/contactor is aware of the ecological and programme constraints so that these can be taken into account in the construction programme from the start, along with any associated risks of delay (owing to weather conditions, for example).
  • An environmental action plan is a useful tool to outline the site-specific ecological constraints and programming restrictions, to communicate these to the contractor and for ongoing monitoring.
  • The implementation of ecological mitigation is highly dependant on local weather conditions and so this risk must be included in EIAs and communicated to the wider team.

This article was written as a contribution to the EIA Quality Mark’s commitment to improving EIA practice.

Richard Farmer is a senior environmental consultant in the Jacobs environmental assessment team


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