Riverine Flooding (Fluvial) and Surface Water Flooding (Pluvial) Model

Overview

Flooding from fresh water (as opposed to sea water) is referred to as riverine flooding. Surface Water flooding (Pluvial) covers situations of surface flows, flash floods or storm water. Riverine flooding (fluvial), which is flooding due to rainfall, or snow melt in the entire catchment upstream of the location. Surface water flooding (pluvial), which is flooding due only to rainfall in the immediate area.

Local Context Data Use

Flood maps used in the Climate Risk Engines analysis must contain water depths and flood extents for flood events characterised by Annual Return Intervals (ARI), for example, a flood map for a 1-in-100-year flood that shows the depths of the flood water.

Baseline Hazard Data

To consider changes to the probability of flooding due to climate change, projected changes to precipitation must be examined.

Climate Change Projections

Climate change impacts on precipitation and flooding use the locally downscaled modelling of future precipitation changes using GCM and RCMs. The Climate Risk Engines use annual maxima of daily rainfall totals from climate simulations and historical observations to estimate the changes in return frequency of floods. The Climate Risk Engines automatically select GCM data based on those models which have strong precipitation signals over the region in which they operate.