A series of studies was carried out in relation to a proposed development at Blackbridge, Milford Haven and at the former Gulf Oil Refinery at Waterston, Pembrokeshire. These included the preparation of a Cultural Heritage Impact Assessment and an ASIDOHL2 study (Assessments of the Significance of the Impact of the Development on the Historic Landscape).
The ASIDOHL2 study was required to assess the impact of the proposed development on the Milford Haven Waterway Landscape of Outstanding Historic Interest (HLW (D) 3), which itself is subdivided into a number of separate Historic Landscape Character Areas (HLCA). These landscapes, and the character areas that comprise them, are unique to Wales and, in part, represent a recognition that historical significance can rest with specific areas as much as it does the sites and monuments that populate them.
The methodology for carrying out an ASIDOHL2 study is divided into five stages: Stage 1 consists of data gathering and the preparation of an introduction; Stage 2 assesses the direct physical impacts of the proposed development, in absolute terms, relative terms and landscape terms; Stage 3 assesses the indirect impacts of the development, in terms of both physical impacts and (non-physical) visual impacts; Stage 4 evaluates the relative importance of the Character Areas (HLCAs) affected by the proposed development, in relation to the Historic Landscape and the national context; and Stage 5 combines stages 2 to 4 to assesses of the overall significance of the impact, including an examination of mitigation or positive benefits and a concluding statement.
The ASIDOHL2 study carried out for the Blackbridge development: described the proposal and planning background in detail (Stage 1), assessed the direct impacts on two Character Areas as Slight and one as Moderate (Stage 2), assessed the indirect impacts on five Character Areas to be Slight and two as Moderate (Stage 3), evaluated the relative importance of one of the Character Areas as High and the rest as Considerable (Stage 4), and assessed the overall significance of the impact as Moderate on two of the Character Areas and the rest as Slight (Stage 5).
The study led to further development considerations, including mitigation proposals and statements on potential positive benefits.