Longitudinal Protection
2022
JOHANNESBURG - GAUTENG - South Africa
JOHANNESBURG ROADS AGENCY
Uyapo Engineering Projects CC
BMK Consulting Engineers (JHB)
KILLARNEY STORM WATER CHANNEL
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Problem
The Killarney Golf Course is situated parallel to the M1 highway, which has a storm water network running through it. This is one of the catchments for Parktown, Killarney and Houghton (Johannesburg). The rapid urbanisation of these areas resulted in an increase in impermeable surfaces which has led to a higher volume of water flowing through the storm water channel. This caused extensive erosion on the banks and multiple failures of earth-retaining structures implemented within the channel. The client required a sustainable solution that could effectively manage the surge in storm water flow while preserving the natural beauty of the golf course.
Solution
Maccaferri designed, supplied, and supervised the construction of a 175m channel to contain a 1:10 year flood discharge of 85 cu m. Gabion side banks, of 2-3m, were designed using a 1m rapid draw down water table. To address the high velocity of the water and prevent scour, the channel bed was constructed with concrete capped gabions. Gabion anchors were implemented at ±20m intervals to prevent outflanking. It was advised that continuous maintenance was to be carried out to minimize the vegetation growth within the channel as this would decrease its discharge capacity.