Upgraded Orange Grove culverts ‘to boost safety’

14 February 2017

 

The upgrading of two old underground water pipes lying beneath the Patterson Park South Recreation Centre in Orange Grove in Region E to increase their capacity to carry increased flood water is “progressing very well”.

 

The project, which is spearheaded by the Johannesburg Development Agency (JDA), the City of Johannesburg’s infrastructure development and maintenance entity, is expected to be completed by the middle of the year, according to JDA Chief Executive Officer Thanduxolo Mendrew.

Mendrew says of major significance, the upgraded underground water pipes or culverts would enhance the safety of residents and protect properties in surrounding areas.

The project was initiated after it was established that the recreation centre’s building lay in the drainage line of the Norwood Stream.

Further hydrological evaluations revealed that the culverts were inadequate to carry flood water in accordance with modern practice. They can only carry water equivalent to a 10-year flood. Modern practice stipulates that a 100-year flood should be the design standard.

“What this essentially means is that the current capacity of a 10-year flood can only accommodate flood levels for the kind of flood that has a 10% chance of occurring in any given year. To adhere to the modern design standard, the capacity of new culverts will be to build to accommodate the kind of floods that have 1% chance of occurring in any given year,” says Mendrew.

“Such floods were recently experienced on two consecutive days in Johannesburg in November last year.”

The upgrading of the two culverts, which started in June 2016, will result in their enlargement, which will increase their capacity to intercept water in the valley bottom under the existing tennis courts and from the western culverts.
The convergence of the waters from these two culverts will form a pond, called the Celebration Pond.

From the Celebration Pond, the stream will flow naturally for about 400m to Louis Botha Road, where the water will re-enter the existing drainage system.

“The advantages that will come from this project include safety and ecological benefits,” says Mendrew.

The park will be further greened and landscaped and the recreation centre and properties in the area protected from floodwater. The two pedestrian bridges being constructed will assist residents and visitors to cross the stream.