Whether or not the HWMF site selection process is specified by existing national or local regulations, as determined in Task 4 above, the following comprehensive, multi-step process can be used to supplement that process. The site selection process needs to follow the public consultation plan designed for this project in Task 5 above in compliance with applicable regulatory requirements. 

Step 6.1  Identify and Evaluate Site Selection Factors

Based on inputs from Task 4 above, identify regulations that specify locational criteria for different types of HWMFs.  Note that the first and most important site selection consideration is whether the relevant government authority has established a law or policy prohibiting or restricting hazardous wastes generated in one jurisdiction from being transported through, or disposed of in, any other jurisdiction.  Locational criteria will include both inclusionary criteria, i.e., natural or manmade landscape features the facility site should be located on or near, and exclusionary criteria, i.e., features the site should avoid locating on or within some specified distance of. Table X provides an illustrative list of potential site locational factors. For each such criterion, determine the method of scaling it, i.e., absolute quantitative (e.g., actual wind speed), relative quantitative (e.g., using a score of 3 is best for a given factor, 2 is moderate, and 1 is worst), or purely qualitative (e.g., indicating types of nearby land use).  Then assign an importance value to each locational factor relative to the other locational factors. 

Step 6.2 Map and synthesize site selection factors to identify candidate sub-regions or search areas

 Utilizing a suitable base map obtained from the relevant local or regional government’s planning or public works departments, map the occurrence of each value or interval of values for each locational factor. Then overlay and synthesize the individual locational factor maps to yield sub-regions, or “search areas”, ranging from least to most suitable with respect to impacts on human health and environment for any given type of HWMF.  A Geographic Information System, or “GIS”, can be used to facilitate this process. A GIS is a system of specialized computer hardware and software that can store, manipulate, and display large amounts of spatial data.  For more information on GISs, go to www.gis.com.  Figure Z shows a series of schematic maps illustrating the process of narrowing down the geographic scale of site selection which is described in Steps 6.2 through 6.4.

Step 6.3 Screen Search Areas to Identify Long List of Candidate Sites

With some candidate search areas thus identified, the next stage of the process focuses on identifying specific candidate sites and relies more on technical and economic feasibility factors, as well as a more detailed evaluation of the environmental and social factors screened earlier. For most types of HWMFs, this would include transport distances from generator or accumulation areas, search area size and configuration relative to the necessary facility footprint and layout, proximity to population and sensitive land uses such as hospitals or schools, and proximity to protected areas such as wetlands or biodiversity preserves. For a hazardous waste incinerator, additional factors for evaluation would include wind direction and speed at different times of the year, area topography relevant to air emissions dispersal, etc. Evaluations at the search area scale will be done in more depth than the regional overlay mapping and will involve field checking. Note that some factors may have already been addressed at the regional scales, but need to be confirmed through field observation visits at the search area scale. This stage of the process yields a long list of candidate sites meeting minimum criteria concerning technical, economic, social, and environmental suitability.

Step 6.4 Screen Long List to Select Short List of Candidate Sites

Study the long list of candidate sites in more depth at the site-specific level, involving not only site visits but actual testing as well. Site-specific evaluations include land area/configuration, availability, and cost; soil testing for geotechnical engineering characteristics; and surrounding topography as it would affect wind speed and direction at the site. From this information, narrow down the long list of candidate sites to two or three final candidate sites and rank them in order of preference. These sites should then be the focus of a full environmental impact assessment, including a preferred site and one or two alternatives, as described below in Task 7.

Alternative Site Selection Process.  An alternative and more intuitive site selection process can be used where the needs of the facility are more straightforward and/or the landscape is less complex regarding where those needs are best met or not met. Such a process would involve skipping the systematic regional and search area evaluations above and going straight to a long list or short list of candidate sites, usually based on qualitative judgments by locally recognized experts relative to the locations of certain most constraining locational factors, e.g., already disturbed or abandoned areas not near population or sensitive land uses. However, while these processes may appear to save money in the short run, their lack of procedural and quantitative rigor, or their assumptions about the suitability of already disturbed areas, may result in poor site selections and costly problems in the long term.