This newly developed R40m Industrial site comprising of 3 platforms. The upper platform adjacent to the site’s entrance designated as Sectional 01. Has approximately 7000m² of leveled ground and 1000m² of cut bank.

Earlier Civils works of making hard engineered surfaces and the removal of vegetation changed the geotechnical properties of a soil. Resulting effect was on hydraulic conductivity meaning low seepage capacity and high surface runoff during high storm.

The surface run- off problem also attributed to the site’s geological composition. Ground on the southern side which constitutes 60% of this Section’s land size is mainly shale bedrock interbedded in layers.

For a newly developed site plans for Industrial Building Structures in the process of approved. Storm water runoff on Section 01 had not been an item of big concern up until Building Works on the lower section designated as Section 02 were underway. Flooding, debris accumulation presented serious concerns on Section 01.

Solution.

After several discussions between Developers and Dson Industries. Construction of a temporary storm channel was approved. One of goal of the goal was to establish a range of input parameters to implement a greater design standard.

Design Parameters.

• Rainfall intensity
• Protection of property
• Storms of short duration and high intensity (similar to the 10 Cotober 2017 Durban Floods )
•  To avoid flooding in the channels the minimum velocity of the flow to be 1.5 m/s.

Channel Specification

• 450mm channel 5000 mm of the bank edge along the length of the bank.
• Falling 0.8% from the centre line to one side into the existing V drain and 0.8% on the other side into a temporary manhole, to act as a silt trap.
• The ground to the opposite side of the bank be cut to a fall from 5000mm to the channel at a slope of 1:10.
• top of the bank to be cut level for 2000 mm and then fall 1:10 toward the channel for 3000 mm.
• cut along the length of the channel to accommodate the fall of +- 500mm.