Using Historic Landscape Characterisation

Using Historic Landscape Characterisation
ASIDOHL is a 5-Stage process, of which Stage 4 is the most interesting for HLC
applications.
Cadw anticipates that Stage 2-4 results should be relatively readily agreed by all
parties at a public inquiry, thus focusing debate constructively on the key issue of
impact assessment in Stage 5.
Stage 1 – summarise the context of proposed development, and scope of ASIDOHL.
Stages 2 & 3 – qualify physical (direct) and non-physical (indirect – e.g. visual) impacts
of the proposed development, measuring them against both the footprint of the
proposed development and the large HLC Character Area(s) on which it impinges. The
essential link between site assessment and landscape assessment, which provides
landscape-scale context for historic features.
Stage 4 – moves on to evaluating the importance of the various aspects of the historic
environment affected by the proposed development. It does this by using the Register
descriptions and also the more detailed mapped and text-based HLC characterisations
that are prepared for register areas by the Welsh Trusts. This assessment operates at
landscape scale by setting the evaluation in relation to
the whole of the HL Character Area(s) affected, then
the whole of the Registered landscape area(s) in which they sit, and finally
an assessment of where these aspects fit in a Wales-wide national context.
In terms of English HLC, the relevant levels would be
HLC Type and/or Broad Groups
LCA character areas, in historic units such parishes
HLC at county level (other areas with similar mixes of HLC types)
at national level (and in future regional too).
Stage 5 – uses a predefined quantitative scale (with six levels, e.g. very severe,
moderate, very slight) to measure overall impact.
ASIDOHL is a complex and sophisticated technique only crudely summarised here.
The full method, with a recommendation that it should be used by ‘archaeologists with
historic landscape expertise or landscape practitioners, familiar with landscape
approaches to the historic environment’ can be found in the Guide to Good Practice in
Using the Register of Landscapes of Historic Interest in Wales in the Planning and
Development Process (Cadw 2003) and, with case studies, on the web pages of CCW
(www.ccw.gov.uk) and Cadw (www.cadw.wales.gov.uk) or those of the Welsh Trusts
www.acadat.com, www.cpat.org.uk, www.ggat.org.uk, www.heneb.co.uk.
For characterisation – for its wider view, contextual framework and conceptual
parameters – it is Stage 4 that is most relevant. Interpreted broadly, and through as
wide a process of participation, this method should enable HLC to play a significant
role in responding to known specific proposals and therefore takes its place in the
EIA/Development Control process. As such it is one of the key areas of HLC’s wide
palette of applications. The nature of its use and value for this differs from the
strategic evaluation contributed by HLC to, for example, work on the M11 and
Thames Gateway Growth Areas, but HLC should be used at both stages – at the
strategic masterplan level and at the stage of evaluating detailed proposals.
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