Landscape & Visual Impact Assessments (LVIAs) are used by developers to bring about change within the landscape while avoiding, reducing or offsetting negative impact on the landscape. Local planning authorities (PLAs) often review LVIAs as stand-alone reports within a planning application, or as part of larger Environmental Statement (ES), in order to assess the likely impact of proposed development on the landscape. LVIAs focus in on the two distinct aspects of 'landscape character' & 'visual amenity'.

'Landscape character' is a term used to describe the uniqueness of a particular landscape. For example: a landscape could be described broadly as being 'rural' or 'urban'. Furthermore, a 'rural landscape' could be described in more detail as having 'gentle hills, characterised by a patchwork of fields, hedgerow & wooded areas' & each of these individual attributes described in greater detail so the 'wooded areas' for example, could be defined as a mix of 'ancient woodland & broadleaf woodland'.

'Visual amenity' is a term used to describe how the landscape is seen, perceived & appreciated by people. For example: a 'bridge over a canal' is viewed & appreciated very differently by a person living on canal-boat near the bridge, to someone walking over the bridge or a motorist driving past on an adjacent road. 'Visual amenity' is the measure of pleasantness experienced by people from different situations.

In order to assess the likely impact of a proposed development on a landscape, a defined Study Area is required. While there is no fixed size for a Study Area, it is ultimately defined by the landscape architect but should include the area of proposed development & the full extent of the wider landscape that the development might significantly influence. Typically this might extend up to a 2-3km offset from the development boundary but it could be much bigger (25km) or significantly reduced (500m). The size, scale, massing & particularly the height of a proposed development can have a significant impact on the size of the Study Area & ultimately the cost of an LVIA.

The LVIA's 'Baseline Assessment' identifies, describes & records information about the existing landscape features, landscape character & landscape characteristics, while visual amenity is usually articulated through a series of representative views or 'Viewpoints' within the Study Area. Both landscape character & visual amenity use five key factors (susceptibility, value, size/scale, duration & reversibility) to determine their significance. The word 'significance' can sound like throw-away term, but in planning terminology, significance is both quantifiable (major / moderate / minor / negligible) & qualifiable (beneficial or adverse) so is always somewhere on a continuum & has meaning. The assessed 'significance' of both existing landscape character & existing visual amenity provides a benchmark against which potential change can be measured.

The Baseline Assessment is followed by a detailed description of the 'Proposed Development' that gives sufficient detail for the reader to understand how the development might potentially impact the surrounding landscape character & visual amenity. For example, a residential development project would describe the number, massing, type, height, dimensions & physical appearance of the houses, a description of the landscape masterplan including a hard landscape strategy & soft landscape strategy, & other planned mitigation strategies.

The Assessment Stage of an LVIA identifies the landscape character & visual amenity components (known as 'landscape receptors' & 'visual receptors' (also know as Viewpoints) that are likely to be affected by the scheme & projects forward to different stages of the project's existence (construction / operational / decommissioning) to determine the likely impact, known as 'Significance of Visual  Effect' & 'Significance of Landscape Effect' respectively. This is also measured on the 4-point scale.

At this stage, the LVIA explores possible design measures that could be introduced into the scheme & used mitigate adverse effects before the LVIA process is reworked to measure the effectiveness of introduced mitigation until a satisfactory result is achieved.

Informed professional judgement should be used to determine what makes 'Significance' but decisions should be methodical, evidence based & able to be justified. Ideally long term-term residual effects of a proposed development should not exceed 'Minor Adverse' in terms of significance to the overall landscape character & visual amenity.