Results
Litter estimation
Large litter loads were found in the upper reaches of the Lotus River due to informal settlements and high density residential zones in this area. The distrubution of litter informed the development of an implementation strategy.
Implementation strategy
Due to a lack of recent litter loading data, it is proposed that a phased approach be undertaken. This would allow for smaller upstream traps to act as pilot projects in order to inform the design of future traps further downstream. A three phase approach is recommended.
Suitable Trap Sites
Research conducted showed that two traps were ideal for the study area. The Stormwater Cleaning Systems Structure (SCS) is suitable for areas where there is a sudden change in elevation (head change). The Urban Environmental Management (UWEM) concept is ideal for flat areas. Four suitable sites were found for the SCS structure and three were found for the UWEM structure.
Hydrological assessment
The peak flows were determined for the proposed Phase 1 traps. This was done using the PCSWMM programme and a 1 in 2 month return period. This period uses probability to determine the maximum flow that can occur every 2 months.
Conceptual trap design
The conceptual design of the Phase 1 traps were completed. Both these traps were that of SCS structures.
Model shows peak flow at two locations.
Model shows peak flow at two locations.