This layer highlights the 1 km channel cells which are upstream of an ERIC flash flood reporting point (Figure 1). The cells are coloured according to the exceedance probabilities of different return period thresholds at the ERIC reporting point at the downstream end of the shaded cells. The rules for shading the cells are shown in table 1 below. The intention of this layer is to highlight the river channel network which may be susceptible to flash flooding.

Figure 1. Example of the ERIC Affected Area Layer shown in the yellow, red and purple shaded cells
Cell ShadingExtremity LevelExceedance Probability (P) Class

Medium

P(RP2 > 15%)

&

P(RP5 <= 5%)

High

P(RP5 > 5%)

&

P(RP20 <= 10%)

Severe

P(RP5 > 5%)

&

P(RP20 > 10%)

*RPxx = return period threshold level, e.g. RP5 is the 5 year return period.

Table 1. The exceedance probability rules for shading the 1 km cells upstream of each ERIC reporting point shown in the ERIC Affected Area layer.