The variability of two lake gravel beaches (Loch Lomond, Scotland) is described in the context of changing environmental conditions. Waves, water levels and wind orientation and velocity were recorded for 1 year. The wave climate comprises small amplitude, high frequency, short-period waves and periods of calm (mean frequency = 0.92 secs; mean significant wave height = 0.08 m). Incident wind-wave direction was an important influence on beach morphology. Water levels fluctuate and there is a general increase in level. Wave activity combined with high water levels affects the upper beach and backshore although here, the highest waves were recorded at low water levels which minimised wave damage.
Cliff erosion rates were recorded. Beach morphological changes showed highly variable profile types which were closely related to beach elevation, exposure and sediment supply. Sections of beach represented by individual profile types showed re-occurring profile types and different sections of beach responded differently to similar conditions. Specific characteristics e.g. narrow beach form, steep foreshores, scarps, beach ridge formation and preservation were noted and a morphological classification for coarse clastic beach profile types was devised. Beach planform is complex and antecedent morphology can persist for some 10 years. Sediment movement is restricted to individual bays which behave as sediment cells. Recommendations for shore management plans which are closely linked to the geomorphological and sedimentological conditions at specific sites within the context of the whole shoreline are given. These have wider application for restricted-fetch coarse clastic beach sites.