KZN’s flood radar ‘nowcasters’

22 January 2003

A KwaZulu-Natal civil engineering researcher has started groundbreaking work to help predict floods up to six hours in advance so that authorities can be proactive rather than reactive when disaster strikes.

The Water Research Commisson is funding efforts by academic Geoff Pegram of the University of Natal to develop technology to forecast floods. This includes the ability to ‘nowcast’ where floods can be forecast up to six hours ahead, using radar technology and computer-based mathematical techniques.

“Floods are a daunting phenomenon that can cause widespread loss of life and damage,” says Pegram, adding that floods in the province are expected to become increasingly destructive.

Pegram says that using radar technology to forecast floods is more effective than using ordinary rain gauges, which do not provide real-time rainfall information and are poor at estimating rainfall in spatial detail over a large area.

The technology is already being used. A model has been installed in the Umgeni Water offices in Pietermaritzburg and at the Flood Management Centre at eThekwini (Durban) Metro Water.

“The weather radar gives an almost instantaneous picture of where rain is falling in great detail over a large area,” says Pegram.

Coastal cities like Durban will benefit particularly from weather radars, as forecasters will be able to detect what rainfall is coming in from the sea in areas where there are no rain gauges.

“An extra half-hour bought is a possible saving of life,” says Pegram.

In addition, flood-prone informal settlements can benefit as the weather radar will be used as an early warning system to reduce flood damage and give water resource managers extra time to implement preventative measures.

“It is hoped that this pilot study in KwaZulu-Natal will be so successful that other municipalities and water management authorities throughout South Africa will adopt the technology,” said university spokesperson Amelia Naidoo.

Naidoo said the Water Research Commission had granted Pegram’s research team a new contract to run for three years, entitled ‘National Flood Nowcasting System Towards an Integrated Mitigation Strategy’.

Role players in the study include Umgeni Water; Durban Metro’s Disaster Management team; Durban Metro’s Drainage and Coastal Division; the South African Weather Service’s electronic research, development and maintenance arm Metsys (Meteorological Systems and Technology); the Metsys team in Bethlehem in the Free State; and the Department of Water Affairs and Forestry.

Source: BuaNews

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