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As our focus on the role of archaeology within planning continues, this latest blog explains what a desk-based assessment (DBA) is, what it includes, its purpose, and the most common types.

What is a desk-based assessment?

A desk-based assessment is a study of existing information used to evaluate the known or potential heritage assets of the historic environment of a specific area.

The definition of ‘historic environment’ is provided in the National Planning Policy Framework (NPPF) glossary as “all aspects of the environment resulting from the interaction between people and places through time, including surviving physical remains of past human activity, whether visible, buried or submerged, and landscaped and planted or managed flora”.

As outlined in this definition, the historic environment encompasses a wide range of assets including buildings, buried sites, earthworks, ancient woodlands, historic parks and gardens, among others.

To inform a desk-based assessment, a variety of sources must be consulted. These include, but are not limited to, data from the local Historic Environment Record (HER), local archives, historical maps, aerial photography, LiDAR imagery and regional research frameworks. A site visit is also typically conducted to assess the character of the area, identify visible historic features, and evaluate factors that may affect the survival and condition of known or potential heritage assets.

What does a desk-based assessment include?

A desk-based assessment typically includes:

information on the topography and geology of the site and its surroundings
details about the proposed development
a historic environment baseline search, identifying and briefly describing known heritage assets within a defined study area (using the HER data)
consideration of factors that may have affected the condition or survival of heritage assets
an assessment of the potential for archaeological remains within the site, their likely significance and the impact of the proposed development
a review of relevant regulations, policies and guidelines

The purpose of a desk-based assessment

Desk-based assessments can be used for a variety of reasons; however, in this blog we focus specifically on their role within the planning context.

A desk-based assessment is usually the first step in the process of investigating and informing on the historic environment in relation to pre-application advice or a planning application. It helps inform the local planning authority’s decision on the impact of a proposed development on the historic environment and whether further investigation, such as fieldwork, is necessary to mitigate that impact.

Section 207 of the NPPF requires that, when determining planning applications, local planning authorities should ask applicants to describe the significance of any heritage assets affected.

If a proposed development site includes or has the potential to include heritage assets with archaeological interest, the local planning authorities should require the submission of an appropriate desk-based assessment and, where necessary, a field evaluation. The level of detail should be proportionate to the assets’ importance and no more than is sufficient to understand the potential impact of the proposal on their significance.

Types of desk-based assessment

The two most common types of desk-based assessment within the planning process are the historic environment desk-based assessment (HEDBA) and the archaeological desk-based assessment (ADBA).

Although the principles, sources used and structure of these two reports are very similar, their main difference lies in their focus.

HEDBAs cover all aspects of the historic environment, including archaeological remains, historic structures, listed buildings, landscapes, registered parks and gardens. In contrast, ADBAs are primarily focused on archaeological remains, whether buried or visible on the surface, including scheduled monuments.

The type of desk-based assessment required for a proposed development depends on the characteristics of the specific site and its surrounding historic environment. They are a vital first step in establishing what is already known about the historic environment of a proposed development site, assessing the potential of archaeological and historic environment assets to be present within the site, and determining the potential impact of the proposed scheme on any such assets.