Previous cyclones and floods

Cyclone Helen 2008 – urban and rural impact

In the early hours of 5 January 2008, Cyclone Helen a Category 2 cyclone, came close to Darwin and rural areas.

‘Helen’ caused considerable damage to our suburbs, including significantly disrupting the delivery of power, water and sewerage services, even though it did not track directly over Darwin.

In almost every case damage to Power and Water services was caused by falling trees and was not because the power and water systems had stopped working.

At the time of the ‘all clear’ at 6am, more than 15,000 homes and businesses were without power.  Damage to the power network included broken high voltage and low voltage conductors, broken or twisted cross arms, bent and twisted power poles as well as some streetlight damage.

Water and sewerage services sustained less damage, again mostly affected by trees falling on or uprooting equipment.

Power and Water’s response

  • At the ‘all clear’ Power and Water repair crews were out on the roads evaluating damage and restoring power, based on importance.
  • Our priorities were to repair and restore major feeders safely and not endanger people by connecting fallen powerlines and house services.
  • By late afternoon electricity supply was restored to some 12,000 customers.
  • By the next afternoon less than 560 properties were without power. These were mainly in rural areas, which in some cases were inaccessible due to flooding.  Others were individual properties with damaged service connections to their homes.
  • Standby generators were used at sewerage and water pumping stations affected by power outages, also sewage pump out trucks were prepared to ensure sewage overflows did not happen.
  • Power and Water repair crews worked 12 hour shifts, day and night, over four days to restore services as quickly as possible.
  • Call Centre staff were on duty in Darwin and Alice Springs throughout the weekend and took more than 3000 customer calls in the first 48 hours.
  • Regular updates about restoring power and water were issued via print, radio and TV.

Gunbalanya (Oenpelli) flooding 2007 - remote area impact

Gunbalanya is located about 330 kilometres east of Darwin and 60 kilometres north east of Jabiru near the East Alligator River in Arnhem Land with an estimated population of 1100 (including outstations). In early March 2007, a cyclonic low developed into Tropical Cyclone George and 930 millimetres of rain fell in seven days with 311 millimetres on 1 March 2007, causing significant flooding at Gunbalanya. The potable or drinking water supply continued to flow with no apparent damage to the reticulation system, and the water mains had maintained positive water pressure with no evident risk of contamination. All sewerage pump stations were submerged under flood water.

Power and Water’s response

  • A ‘boil your water alert’ was issued in case there was contamination.
  • Power and Water sampled and tested the water to confirm it was safe to drink.
  • Waters began to recede on Sunday 4 March 2007 and Power and Water employees returned to the community on 5 March to evaluate the water and sewage situation.
  • There was some water damage to the electrical control switchboards that needed checking. These were repaired straight away in time for the flood water to subside.
  • By Monday 5 March two main sewerage pump stations were operational and the flood water was moving back. The two remaining pump stations were still under the flood water.
  • Power and Water employees travelled by helicopter to check the bore field which had suffered extensive flooding, but there was no damage to the infrastructure or to the power distribution system.
  • The bores were functioning and there was no threat of water contamination as the bore heads were sealed.
  • Power and Water employees, and contractors worked to renew the electrical components of the main switchboard that were water damaged, and contractors continued to repair the measurement system which captures and measures information in remote areas, and transmits it to a central point, in this case the borefield tank.
  • Communications between the borefield tank and the main town tank were lost during the flood and the system had to switch to manual operation.
  • All essential repairs were completed within three weeks from the time of the flood.

Cyclone Monica 2006 – remote area impact

On 24 April 2006, Cyclone Monica, a Category 5 cyclone, moved from the Queensland east coast into the Northern Territory, affecting the small islands north of Arnhem Land.  It made landfall on the northwest Arnhem Land coast, about 35 km west of Maningrida, and cut through a number of remote communities including: Yirrkala, Mangarr, Galiwinku, Elcho Island, Ramingining, Ngangalala, Yathalamarra and Millingimbi.

A small but intense cyclone, it also caused significant damage to the Arnhem Land communities of Oenpelli and Maningrida before striking Jabiru.

Much of the damage was to power poles and powerlines.  Power in remote areas is especially crucial as it often runs the bores for water and the pumps to refuel aircraft that deliver essential supplies to these areas.

In most remote communities Power and Water’s local representative is an Essential Services Operator, or ESO. Our Remote Operations employees worked with the ESOs and contractors to restore essential services.

Power and Water’s response

  • In the early hours of Tuesday 25 April, the town of Jabiru had no power but by 10.30am power had been restored to most of the town.
  • Power and Water flew a repair crew to the town and two additional crews drove to Jabiru to help complete the recovery process.
  • By Wednesday a detailed inspection of the network had been undertaken.
  • A tree trimming program was set up in the town to prevent more extensive damage to the network.
  • In remote areas the damage to services was repaired and power was restored in a day.
  • Four Power and Water staff flew to Maningrida to help with repairs, along with electrical contractors.

Katherine/Daly River region flooding 2006 - urban and rural impact

On 6 April 2006, Katherine flooded for the second time in eight years, resulting in hundreds of people being evacuated from homes and businesses. The town was completely cut off due to flooding on the roads. The communities of Daly River, Beswick, Jilkminggan, Binjarri, Barunga and Eva Valley were also affected by flood water. In Katherine, electricity had to be disconnected to 130 customers because of flooding or expected flooding. Community members from Jilkminggan were evacuated to Mataranka.

Power and Water’s Remote Operations employees worked in difficult and trying conditions to ensure the safety of our customers and to make sure that infrastructure and equipment were protected, and remained operational. There was slight damage to facilities and services upgraded after the 1998 floods.

Power and Water’s response

  • Once the flood water had receded, Power and Water networks' employees checked houses and customers who were not affected by flooding, and restored their power.
  • Casablanca Estate had to be isolated as flood water had covered low voltage pillars and power was restored after the infrastructure was checked by Power and Water employees.
  • Network employees isolated the whole of Kalano until water subsided, checked the system and then restored power.
  • Town water supply was switched from river water to bore water and systems were checked. Once water had receded the water supply was flushed and tested.
  • All sewer pump stations were monitored and pump stations that were under water continued to run. All sewer pump station switchboards were clear of flood water.
  • A sewerage dump point was needed for travellers and Power and Water worked with Environmental Health.
  • In Mataranka properties either side of the Little Roper were isolated by the Essential Service Operators because of flooding. When it was safe they restored the electricity.
  • In Jilkminggan, all systems were checked by Remote Operations employees by helicopter. The automatic chlorination unit had stopped working and was repaired. Employees then visited the site to flush the water supply and chlorinate it as needed.