What is a Walkover Survey?
A walkover survey allows the assessor to see visible signs of contamination at a site to determine the potential risk to site users or to confirm the absence of such contamination. It is often an essential part of a contaminated land investigation for a planning application.Get In Touch
How To Conduct a Walkover Survey?
In order to carry out a Phase 1 Preliminary Risk Assessment (desk study), a walkover survey will usually be required to allow the assessor to identify visual or olfactory evidence of contamination on a site that would otherwise be impossible to identify without visiting the site. A walkover survey for a contaminated land investigation is a simple process that involves visiting a site to make observations of potential contamination sources and pathways. The Environment Agency’s Land Contamination: Risk Management provides guidance for a walkover survey for contaminated land investigations:
Identify Contamination Sources - As outlined in Environment Agency's Land Contamination: Risk Management guidelines, a site walkover should record information such as the:
• current use and status of the site - occupied or vacant
• general condition of site and surrounding land use
• presence of visual surface staining and odours
• topography and surface condition - open ground, hardstanding and other geotechnical or surface features
• local surface water features
• presence and type of vegetation
• presence and extent of any invasive plant species
• buildings and below or above ground structures such as fuel tanks
• above and likely below ground services
• access and security
Conceptual Site Model - Once potential sources of contamination have been determined by the walkover survey, potential pathways are identified to assess the possibility of pollutant linkages being present. This will involve collecting information on the:
• type, extent, location and behaviour of potential contaminants
• information on site drainage and other man-made potential pollutant pathways
• type of receptor you are dealing with - for example, human health, controlled waters, ecology or property
• characteristics of the people and the environment potentially affected by the contaminants
Why Do I Need a Walkover Survey?
A desk study alone may not be able to identify contamination sources that aren’t visible on maps and in photos so these may go unnoticed. For example, very rural sites are unlikely to be very detailed on a map and there may not be a lot of information available for the site in online databases. Therefore, a walkover survey is necessary to identify site specific contamination risks.
Even small sites where contamination is not expected to be present a walkover survey will often be needed in order to confirm the absence of contamination sources and confidently conclude a low level of risk. During a site investigation, a walkover survey can also allow the assessor to obtain anecdotal evidence of potential contamination at a site, from site owners, users or neighbours, which would otherwise be impossible to identify without visiting the site and talking to local residents or workers.
Walkover surveys are often an essential part of a contaminated land investigation for a planning application. Contaminated land planning conditions on a decision notice are often shown as a phased process with the first stage being a Preliminary Risk Assessment or desk study that will often require a supporting walkover survey to be accepted by the local authority.
I Need a Walkover Survey & Desk Study - We can carry out walkover surveys as part of contaminated land investigations for planning applications and due diligence.
1. Contact us and let us know your requirements
2. Following initial consultation we can provide an outline proposal detailing how we can help and the costs involved
3. Our environmental consultants will then carry out a walkover survey as part of a Phase 1 Preliminary Risk Assessment
4. We can visit your site to carry out a walkover survey within days of your initial enquiry allowing you to stick to schedules and minimise any disruption to your project