Water Used to Plan Water Supply For Merged Maritzburg City
The new South Africa continues to pose challenges for engineers. In the old days, water supply lines were often added on "as required" with little or no long term planning. Chris Brand, head of the Water Section at Jeffares & Green Parkman in Pietermaritzburg, has taken on that challenge designing a new bulk water master plan for the new merged city that now includes Edendale.
This huge project is a part of the Integrated Development Plan and forms part of the Regional Services Water Plan. "When we have finished the plan, the engineers will be able to guide the planners to maximise the use of the existing infrastructure," says Chris.
"We recently had a situation where one pipe broke, and a sizable part of the population was without water for 2 weeks, and that is unacceptable."
"There are many variables to take into account in this project, for instance there are 24 000 existing residential units, but there could be as many as 180 000 units when you start projecting into the future," says Chris. "The area we are dealing with is 3 360 hectares."
"The area currently gets its water from the Umgeni, with two feeder pipes into the north-west section, and one into the south western section. Obviously we need to be able to supply as much of the demand under gravity as possible," says Chris.
"This entails replacing the existing command reservoir with smaller ones.
There are 22 existing reservoirs and 6 pump stations and about 62km of 500-110mm pipes.
The existing demand is 276 l/sec peaking seasonally at 414 l/sec. "The pressures are also quite high - 260bar."
"There are also large tracts of land where the owners cannot be traced. We looked at many different models to try and establish defined supply zones."
"I have come to appreciate the handiness of the Water module of Civil Designer," says Chris. "It is very helpful be able to be able to put the drawing in the background. Using the model, you can plug in demand values to see the most cost-effective ways to develop."
"Civil Designer is becoming like a tool the more I use it; I can simply get on with designing. It is also user-friendly and informative. It has meant huge savings to us."
"This is a challenging project to undertake. We have been busy for 11 months now and we are still not finished," says Chris. "The council will be able to use the model to roll out phased implementations."