MOVEMENT PATTERNS OF RIVERINE LITTER

Aspects of litter movement were looked at in a variety of ways. River bank clearances provided valuable information on litter accumulation and movement, showing a distinctive correlation between flood events and litter movement. Introduction of litter outside of channel deposition (diffuse sources) were limited in the study area in South Wales, UK. A rise in litter deposition occurred for some time after flood events, with the main accumulation occurring in the mid-bank zone. As only some litter types have an increased input during flood events e.g. sewage-derived material from combined sewer outfalls (CSO), accumulation of other litter types, e.g. plastic sheeting could be due to their distribution throughout the catchment. A positive correlation between litter stranding and vegetation was found. During high flows, (75.59 cumecs) litter is removed from sites with little restraining vegetation and deposited where stranding potential is high. Smaller items such as feminine hygiene products were more susceptible to stranding than larger plastic sheeting.