JHB WATER: AN OVERVIEW

Derrick Kgwale, COO of Johannesburg Water, gives a perspective on water security within South Africa’s largest metropolitan municipality – City of Johannesburg (CoJ).

Established in 2001, Johannesburg Water is owned by CoJ and is tasked with the operation and maintenance of the water and sewer network.

As the biggest potable water consumer out of the Vaal River Catchment, CoJ accounts for 40% of water consumption volumes out of the Rand Water Supply System. Water supply security is key to ensuring population and economic growth within CoJ. The Gauteng City Region Water Security Plan (GWSP) outlines CoJ’s obligation for water security and sustainability.

GWSP interventions include:

• reduce water demand

• manage variability to prepare for drought and/or water scarcity

• invest in alternative water sources and tools for water conservation

• manage water quality to limit pollution and achieve environmental goals. The WC/WDM (water conservation and demand management) strategy aims to reduce demand by 37 123 Mℓ/ annum through the following strategic interventions:

• repairs of leaking reservoirs and tower infrastructure

• repair and replacement of zonal bulk water meters

• active and passive leak detection

TABLE 2 Reservoir storage rehabilitation

• establishing new pressure management zones and minimum night flow analysis

• retrofitting and removal of wasteful devices (Infrastructure upgrade and renewal)

• by-law enforcement (illegal connection cut-off and reconnection, as well as tampering of City infrastructure for scrap metal)

• replacement and refurbishment of large gate valves

• water pipe replacement

• domestic and large consumer meter replacement.

Ageing infrastructure

Johannesburg Water’s infrastructure assets have a current replacement cost of R115.4 billion. Its asset management plan dictates that a renewal rate of 2% per annum is required. Current expenditure patterns indicate an average renewal rate of 0.92% is achieved with

City Of Johannesburg

• Largest metro in South Africa: 1 626 km2

• 7 administrative regions

• 135 wards

• Population: estimated at >5.7 million

• Population growth (p/a): 2.49%

• 1.8 million households current. Alarmingly, 25% of the asset base has a remaining useful life of less than 10 years.

“Partnerships with the private sector are of extreme importance to Johannesburg Water. This is because we need further investment into our infrastructure to meet increasing water demand. Our rate of investment into infrastructure is smaller than the rate of deterioration. For example, we would like to replace 925 km of pipes in the next five years (185 km/annum); we can only replace 117 km with our current funding. Water losses have increased from 24% in 2019 to 31% in 2022. The lack of capital investment has continued to have an impact on the infrastructure failure rate. The increase in the infrastructure failure rate has resulted in an increase in physical losses,” states Kgwale.

Reservoirs

“Reservoirs are critical to CoJ’s water security. A limited number of reservoirs inhibits CoJ’s capacity to deliver water. There is a need to repair a few old reservoirs and build a few new ones in certain areas,” adds Kgwale.

Pressure management

Johannesburg Water has 765 pressure management zones within its entire water reticulation. Only 22 are smart-controlled. According to the WC/WDM strategy, a further 177 new pressure management zones will be established over the next 10 years. This will be done in a prioritised format to ensure the most beneficial zones are established first. A total of 37 of the new PRV (pressure-reducing valve) zones will be smart-controlled pressure management stations that will be either time- or flow-based.