1. (a) The master plan for the development of the area was approved by the City of Ekurhuleni Metropolitan Municipality. A layout plan was obtained from Ekurhuleni Metro showing the development upstream of the culvert in the flood plain. From this layout plan it is clear that City approved developments based on a 1:20 year flood, which was not shown on the plans, and not based on the 100 year flood as per legislation applicable. The development of the erven is in the flood plain that acted like a natural retention pond. Calculations by our independent experts indicate that the development is in fact below the 20 year flood line. Prior to the property development within the flood plain the culvert acted adequately. Due to the risk associated with the downstream flooding of property if culvert sizes are increased, the size of the culverts cannot just be increased without substantial improvement to downstream drainage by City of Ekurhuleni Metropolitan Municipality.
(b) Due to risk associated with the downstream flooding of property the size of the culverts cannot just be increased without substantial improvement to downstream drainage by City of Ekurhuleni Metropolitan Municipality on their land.
2. SANRAL is aware of the problems in the area especially regarding flooding in the vicinity of Boeing Road and the engineers are in discussion with the City of Ekurhuleni Metropolitan Municipality to address the problem. In addition SANRAL is in a process of appointing professional consulting engineers to assist with a detailed investigation/design to find a solution in consultation with City of Ekurhuleni Metropolitan Municipality.
3. (a) Retention ponds were only mentioned in the flood study as a possible solution to the problem but there were some reservations as to how effective these would be. The limited land space on both sides of the N12 highway will determine the size of the pond/s that can actually be constructed, and thus the size of the flood event that can be retained.
(b) SANRAL has already commenced with the appointment of its own professional consulting engineers to assist with detailed investigation/design to find a solution in collaboration with the City of Ekurhuleni Metropolitan Municipality.