The removal of urban litter from stormwater conduits and streams: Paper 1 - The quantities involved and catchment litter management options

A large quantity of urban litter is Ending its way into the drainage system s from where it is potentially able to travel via the stormwater conduits, streams, rivers, lakes and estuaries until it eventually reaches the open s ea. Along the way items are entangled amongst the vegetation along the bank s or strewn along the beaches to become an eyesore and a potential health h azard. The potential annual cost of cleaning South Africa's waterways of ur ban litter assuming current practices is conservatively estimated to be in the order of. R2 bn. at current prices. The main factors influencing the qu antity of litter finding its way into the waterways are identified, and sug gestions are made for reducing this quantity through catchment titter manag ement. Data from Australia and New Zealand are also reported to illustrate the potential for major reductions in the quantity of litter entering South Africa's waterways. On the assumption that it will take a while for effect ive catchment litter management to be implemented, some South African data on current urban litter loading rates related to land use, vegetation, the level of street cleaning and the type of rainfall are presented. The influe nce of these factors is then summarised in the form of simple equations to assist designers in the sizing of litter traps.