The characteristics of ‘abrupt wave front’ floods on Pennine catchments, northern England, and their transmission downstream

Visible flood waves, described as abrupt wave front events (AWF), have been identified on rivers in northern England rising in the Pennines, from both historical and recent gauged data. The focus of this paper is on the characteristics of two gauged AWF events on the Rivers Wear and Tees in 1983 and their comparison to ‘normal’ floods. The description and analysis is based on contemporaneous photographs and observations and on digital level and flow records. The rapid 15-min rise in these events is compared with the maximum rate of rise in annual maximum peak floods by comparing flood hydrographs. The propagation of the flood wave downstream is illustrated. The 15-min increase in discharge is compared in relation to the peak flow for AWF and normal floods at different gauged locations down the catchments showing striking differences. The character of the AWF response in the vertical or near-vertical wave front and rapid increase in both level and discharge points to the occurrence of kinematic shock waves.