The amount of detail required to undertake a structured appraisal will depend upon the type of decision that has to be made; project appraisal can be used at a variety of different levels. Technical management decisions may require a relatively simple appraisal (see below) while the inclusion of managed realignment as part of a flood defence strategy would be likely to require a more comprehensive and detailed appraisal. The figure below provides an overview of the level of detail that may be required for different types of decision, relating to different management options. The figure only provides an indication of the appropriate level of detail required, but there may be occasions where more (or less) detail is required. It also provides an indication of the point at which project appraisal could be undertaken according to the type of decision to be taken.

Overview of the level of detail needed for the appraisal of different management options; ‘main groups’ and ‘functions’

In most cases, it is likely that the simple qualitative (and, where relevant, quantitative) consideration of the types of functions and services that would be impacted by the management activities proposed (i.e. described in words) will be sufficient to ensure that the ‘best’ decision is being taken. Other cases, however, such as in circumstances where compensatory habitat may need to be provided, are likely to require more detailed appraisal of impacts at the functional level to ensure that the right sort of outcome is achieved. This may require monetary valuation of the impacts, where this would build upon a description of the impacts in qualitative (words) and quantitative (numbers) terms. However, the approach taken to economic decision making is likely to vary based on the number of impact categories that can be expressed (or not) in monetary terms and the nature of the decision being made.

A method presently being used to compare management options is the Appraisal Summary Table (AST). This provides a mechanism for recording all of the predicted impacts (qualitative, quantitative and monetary estimates) associated with different options side-by-side, such that the appraisal process is transparent and auditable, and it is easier to make comparisons. An AST also provides a useful vehicle for presentation of information to, and discussion with, stakeholders when identifying and selecting a preferred option or course of action.

Different decision-making processes are proposed for the different types of decision that are likely to be required but, in all cases, the general approach is the same. The starting point is always to identify the objectives of the proposed actions, to define the baseline environment, to compare the predicted influence of alternative actions on the baseline and then select the action that will provide the greatest benefit, preferably at the least cost.