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8 Soft-modelled impacts Terrestrial ecology and landscape 8.1 INTRODUCTION In this chapter we are going to discuss areas of impact assessment repre-senting in some respects the end of the spectrum opposite to those discussed in the last chapter, being areas where the presence of simulation modelling is virtually non-existent. To focus our discussion we have chosen the areas of terrestrial ecology (a heavily researched scientific area) and landscape, a more subjective area of impact assessment. The reasons for the absence of simulation modelling are very different for each of the two areas, but they have in common the fact that the logic of the thinking pro-cess is more dominated by the substantive content of their disciplines than by the logic of applying particular rules and simulation models of one level of sophistication or another, as was the case with the areas of impact discussed in the previous chapter. In addition, even if both areas conform in general terms to the stages and general sequencing sketched out before (baseline, prediction, assessment, mitigation), they each adopt very different approaches. 8.2 TERRESTRIAL ECOLOGY The breadth and complexity of this field has been well introduced and discussed over the years in the corresponding chapters in well-known manuals: Hanes (1980) and Westman (1985) are good examples of “first generation” discussions of ecology in the context of impact assessment manuals. In more recent times, Petts and Eduljee (1994a), Morris (1995), Wathern (1999) and specially Morris and Emberton (2001) provide more up-to-date discussions which show the considerable complexity of this area of assessment, to the extent that it can be argued that the investigation of this area is so “open-ended” that it goes against the grain of an expert systems approach © 2004 Agustin Rodriguez-Bachiller with John Glasson Soft-modelled impacts 235 (Beaumont, 1994),34 which by definition requires a certain degree of closure. We shall not try to reproduce those expert discussions here, but seek to reduce that open-endedness as much as possible to a logic which could potentially be automated – with particular attention to the role GIS could play – in much the same way as in the previous chapter. For the practice of impact assessment, this area of study is broken down into two: flora and fauna and, in turn, their study can be applied to a terrestrial environment or to a water (fresh, marine, estuarine) environment. In this chapter we shall concentrate on the terrestrial case. As in the case of noise or air pollution, ecological questions can be addressed at various stages in the compilation of an Environmental State-ment: when considering alternatives for the project, when studying the baseline situation, when predicting future effects of the operation of the project, and when considering mitigation measures. However in the case of ecology it is the baseline study that dominates in the consideration of ecological issues and impacts. Although “the best mitigation is by site selec-tion” (Beaumont, 1994), ecology is very rarely investigated when deciding the location of a project. Such investigation is usually not budgeted for by developers, and the most common situation is that impact assessors are called upon when the developer has already acquired the site. Although the detailed assessment of ecological issues is quite complex, the overall logic of ecological impact assessment is quite simple, resulting from the contra-position of the project and all its features with the ecological environment and all its qualities (Figure 8.1). Figure 8.1 The logic of terrestrial ecology impact assessment. 34 The knowledge acquisition for this part was greatly helped by conversations with Nicola Beaumont, of Environmental Resources Management Ltd (Oxford branch), and Owain Prosser helped with the compilation and structuring of the material. However, only the author should be held responsible for any inaccuracies or misrepresentations of views. © 2004 Agustin Rodriguez-Bachiller with John Glasson 236 Building expert systems for IA 8.2.1 Project characteristics and potential impacts The potential ecological impacts from projects relate directly to the land affected by the project, considered under two main headings (Figure 8.2): the land-take by the project itself; and area affected by the functional impacts from the project. The project land-take relates to the area occupied by the various features of the project at various stages in its life. In terms of the information to be collected about the project, it can be seen as the three-dimensional combination (it can be thought of as a three-dimensional “table”) of the project features, the project stages they apply to, and how temporary they are. First, the identification of what the project will involve can follow a typical checklist of all those elements of the project (the main plant and the infrastructure) that will disturb the natural environment in that area: • demolitions to be carried out and safety areas around them; • access roads (and areas around them needed for their construction); • earth-moving/in-filling; • storage areas (and possible safety areas around them); • maintenance and repairs; • buildings; • structures (and safety areas around them); • parking areas; • areas paved for circulation or other reasons; Figure 8.2 Project characteristics for terrestrial ecology impact assessment. © 2004 Agustin Rodriguez-Bachiller with John Glasson Soft-modelled impacts 237 • infrastructure and services; • boundaries (fencing, bunding). Second, it is essential to determine at what stages of the life of the project the different features on the list will have an impact: • pre-construction stage if there is one (demolition of existing structures, clearing the site); • construction; • operation; • decommissioning (if relevant), although, for terrestrial ecology, it is common for this stage to have “positive” rather than negative impacts, as it can involve restoring the environment to its situation prior to the project. Third, whether these features will be temporary or permanent. All these considerations are intended to define and measure the presence and areal extension of the various project features in its various stages. Occasionally, areas inside the perimeter of the project site can remain undisturbed and can be excluded from the consideration for impact assessment, as long as they remain connected to their natural surroundings and are not left as “islands” encircled by man-made areas, or are separated by fences from other natural areas. The functional impacts from the project can also affect the ecology of areas which must be added to those affected by direct land-take. These can be derived from a standard short list of typical functional impacts: • traffic; • emissions into air, water or soil (from the project and from traffic); • noise emissions (from the project and from traffic); • water abstractions; • waste generation. Land-take is the most direct of the impacts on terrestrial ecology, but the land affected by some of the project’s functional effects should also be part of the investigation, as it can involve impacts like depositions from emissions, or indirect impacts like those from traffic and access routes, all of these producing potentially dangerous effects (Petts and Eduljee, 1994a). The assessment of these functional and indirect impacts is part of the respective impact assessments studies (air pollution, noise, etc.), but the identification of the land affected should be an important consideration from the ecological assessment point of view. This should involve, for instance, extending the ecological baseline-study to areas where air pollution is going to impact on the ground, which in turn would mean either postponing the start of the ecological area characterisation until such impacts had been calculated, or © 2004 Agustin Rodriguez-Bachiller with John Glasson 238 Building expert systems for IA anticipating (even if roughly) the extent of the area likely to be affected: for example, a few kilometres downwind in the dominant wind direction in the area. This can be more difficult for some impacts than for others, and is bound to be based on previous experience with similar types of projects, knowing for instance that industrial noise is likely to “carry” over several hundred metres, while motorway noise carries over several miles. As a logi-cal corollary to this emphasis on the identification and measurement of the areal extension of different parts (and effects) of the project and how they overlap with the natural environment, we can already anticipate that the mapping of the project in its environment is going to be central to the whole process, giving a potentially pre-eminent role to GIS and similar technologies. 8.2.2 Area characterisation and ecological baseline Ecological impact is one of the “classics” in impact assessment; therefore it is one of the first to be considered for inclusion in impact studies and is rarely added later as an afterthought. However, some level of scoping is necessary to determine the types of surveys needed, using a form of “scoping desk-study” (Beaumont, 1994) to plan the study and put the necessary team together, based on documentary evidence and second-hand informa-tion. This type of information very rarely refers to the specific site, but focuses more on providing a general picture of the area and its potentially sensitive spots in order to carry out the necessary surveys and collect first-hand information (Figure 8.3). Standard sources for this initial area characterisation are: Figure 8.3 Area characterisation and ecological baseline. © 2004 Agustin Rodriguez-Bachiller with John Glasson ... - tailieumienphi.vn
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