5.4.1 Environment

The key environmental attributes and characteristics of the study area must be summarised.  This should draw attention to the particular qualities of the area, making reference to specially designated parts within the study area and to known proposals for change.

The collation of environmental baseline data is important at the outset to allow an informed view to be taken of the vulnerability of the study area to likely changes associated with transport or other options under consideration.  Baseline data is required to inform both the Part 1 and Part 2 Appraisals.  For the Part 1 Appraisal, the data will be generally limited to readily available existing information.

The collection of information may involve, in the first instance, desk studies of existing records. Where information does not exist or is inadequate for the purposes of making accurate predictions about potential impacts, additional field surveys may need to be undertaken.  Field surveys are less likely to be required where environmental assessment is being undertaken on a strategy, plan or programme rather than an individual more specific option or option level, as the emphasis is likely to be on identification of relevant environmental issues and the broad scale and nature of potential impacts rather than on detailed predictions.

Baseline data should, as far as possible, be adequately documented and of known quality and updated at regular intervals in accordance with reliable procedures.  Gaps and uncertainties in data should be identified.

The key purpose of the Part 1 Appraisal is to allow a comparison of alternative options, enabling those options which are unsuitable on environmental grounds to be filtered out at an early stage. It will also help to scope required appraisals at Part 2.

In summary, it is important to:

• Confirm the nature of the option including the alternatives under consideration;
• Identify if an Environmental Impact Assessment, or Strategic Environmental Assessment is required;
• Identify the range of likely impacts on the environment;
• Identify the extent to which these impacts need to be investigated;
• Identify methodologies to be employed;
• Define data availability and further data gathering requirements;
• Set the indicative thresholds and significance criteria to be used in the Evaluation of impacts;
• Identify broad mitigation measures; and
• Agree the above with statutory bodies.

At the Part 1 Appraisal stage, a qualitative assessment should be completed using the seven point scale assessment, considering the relative size and scale of its impacts.  The supporting information could include:

• How the option will contribute towards reducing emissions of CO₂ and other pollutants, and promote better air and water quality;  
• Are there significant impacts on the environment? and
• What are the distributional impacts, who will be the gainers and losers?

Impact assessment relies on reliable and readily available baseline information to give an indication of the significance of impacts.  The topics for which more in-depth data are to be collected should be agreed between parties following the Part 1 process.