Methods And Approaches Applied At NAIAD

What this list is

The methods on this page were established practice before the project began. They are the ones a reader is most likely to already have access to, through a consultant, a national guidance document or their own training, and the reason to list them separately is that a reader can begin with them and adopt the project's own methods later if they need to.

Each was applied to a question it had not been applied to before. Life cycle costing had not been used to compare a natural system with a built one over the period over which the natural one matures; damage functions had not been applied to a hazard that the intervention itself changes; a choice experiment had not been used to establish what a population would trade for the co-benefits of a measure it had not yet seen. Those applications are the entries' substance.

Economic methods

Life cycle costs methodology — the costing convention, applied across the whole life of an intervention including its maintenance, renewal and the treatment of the asset at the end.

Economic damage costs — the depth-damage approach, applied to a hazard whose extent and depth are changed by the intervention under appraisal.

Co-benefits valuation and cost-effectiveness — the valuation of effects that have no market price, and the expression of the result as a cost per unit of effectiveness where the objective is fixed.

Co-benefits assessment through choice experiment — the stated-preference method, applied to establish the relative weight the population places on the different effects a measure produces.

Modelling methods

Hydrological and hydraulic modelling — the standard chain from rainfall to flow to inundation, applied to configurations of measures whose effect depends on where in the catchment they are placed.

Cost-effectiveness estimation using the flood-excess volume — the published screening technique, applied to establish quickly whether a scheme is worth a full appraisal.