The validity of spatial data-based EIA screening decisions

Screening is an important step in the EIA process as it is here where the significance of possible impacts associated with a proposed development is first considered and the need for an assessment is determined. There is no one-size-fits-all approach to screening, but approaches can broadly be categorised into discretionary approaches and prescriptive approaches. In both types of approaches spatial information can be used to inform screening decisions and, in some cases, determine the screening outcome altogether. This paper explores the validity of spatially based screening decisions by evaluating the possible influence of spatial data on decisions – especially as it relates to data accuracy and scale. A sample of ten screening decisions for South African case studies are reviewed and spatial information analysed to illustrate the possible effects of data accuracy and scale on screening decision making. It was found that screening based on spatial data can lead to both unnecessary EIAs being conducted as well as potentially important EIAs being screened out. It is recommended that screening approaches should allow for more flexibility and allow for discretion where spatial data is concerned.