Australian Weather News
Special Report


Friday, 09 to Monday 12 MAR 2001

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Floods approach record levels on NSW N Coast 15Mar01, 20Mar01
Rainfall for the week to 9am Sunday 11 March  BoM

The flood situation on the NSW North and Mid North Coasts worsened Friday despite an apparent easing of rain after mid-morning. As the immensity of the flooding began making international news, the State Government extended the area declared a natural disaster area to cover all coastal river systems from the Manning north to the Queensland border. With the Clarence River threatening to reach record levels, plans were triggered for the mass evacuation of over 10,000 people in Grafton, one of the region's largest cities, as a precaution against levee breach.

This report covers events from Friday to Monday 9 to 12 March, and other aspects of the aftermath of this notable flood event.

The weather situation and flood forecasting difficulties

Although the surface low had weakened, strong middle level circulation continued over the NSW North Coast. This 500hPa (about 18,000 feet) chart for 11am Friday shows strong relative vorticity or circulation centred over the NSW/Qld border. FNMOC

Rain on the NSW North and Mid North Coasts eased Friday after mid-morning. The low responsible for torrential rain yesterday and overnight moved slowly into Queensland and dissipated, but, to the dismay of those anxiously watching river heights and levee banks, heavy showers continued to rake the area Friday and into Sunday, delaying or prolonging flood peaks, and in some cases resulting in second peaks.

A surface trough from the remnant low still lay across the area on Friday and Saturday, its cyclonic curvature encouraging uplift in a continuing moist easterly flow. Cool air and strong circulation aloft enhanced instability, and resulted in widespread heavy showers, with the heaviest falls in the ranges between Coffs Harbour and Port Macquarie. This gave flood forecasters, already battling with a broad scale event, the added problem of estimating variable, heavy and difficult to forecast rain over about 75,000 square kilometres of mostly rugged country not well served by rain gauges. An added complexity in tidal reaches of the major rivers, which included the Macleay at Kempsey, was the timing of flood peaks and king tides. With major flooding pushing toward record territory in several well populated river systems, these uncertainties translated into a worrying time for authorities and individuals as flood gauges and levee banks were watched and evacuation decisions considered.

Rainfall

As the animation below shows, after torrential rain of up to 400mm in the 24 hours to 9am Friday, heavy showers brought 50 to 150mm to the Mid North Coast generally over the following 24 hours to 9am Saturday. These moved north and became lighter over the next 24 hours into Sunday, though heavy falls on the NSW Northern Tablelands and Slopes produced moderate flooding in some west-flowing rivers (see story 10 March).

The top map shows total rain for the week ended 9am Sunday 11 March. Much of the NSW coast and nearby ranges north of Newcastle received over 200mm, while the highest falls of 600 to over 800mm were on the eastern side of the Dorrigo plateau and in the Bellinger River Valley. It appears that it was the heavy falls on the Dorrigo that fed through the Nymboida river into the Clarence, threatening Grafton with a record flood.

Daily rainfall for the 24 hours to 9am for 7, 8, 9, 10 and 11 March  BoM

Selected high weekly and daily totals for the area:

  5 6 7 8 9 10 11 Week
LOWANNA (CAVANAGHS ROAD) 5 51 56 112 364 155 141 884
DORRIGO (OLD CORAMBA RD) 7.4 24 108 179 329* 114.7 98 860.1
BOWRA SUGARLOAF 10 19 95 114 231 250 100 819
BELLINGEN HYDE STREET 3.8 33 125 166 170 97.6 44.6 640
POINT LOOKOUT 5 26.2 94.6 74.8 235.4 129.6 45.4 611
COMBOYNE POST OFFICE 14 45 168 69 124.4 122 38 580.4
MILLBANK (FAIRLIE DOWNS) 2 26 48 58 137 142 25 438
BELLBROOK (MAIN STREET) 1.8 4.2 54.4 34.6 141.6 132.2 36.8 405.6
UPPER ROLLANDS PLAINS (GREENACRES) 0.4 5.4 115 54 67.2 119 42.4 403.4
COFFS HARBOUR MO 8.6 77 95 50.8 122.6 15 15 384
ELANDS (BLACK SANDS CREEK) 7.6 18.6 117.8 85.4 74.4 57 17 377.8
EVANS HEAD RAAF BOMBING RANGE 9 32 27 32 153 100 17 370
FORBES RIVER (BIRDWOOD) 6 18 90 34 74 132 8 362
GRAFTON OLYMPIC POOL 0 1.4 10 43.6 207 43 25 330
BOWRAVILLE COHALAN ST 3.5 18.5 71 52 103.5 61 19.5 329
KEMPSEY AIRPORT AWS 2 16 98 40 84 39 31 310
GLOUCESTER (UPPER BOWMAN) 5.4 12.8 58 40.4 144.8 35.8 4.8 302

*It is likely that the total of 329mm to 9am Friday 9 March at Dorrigo (Old Coramba Road) was higher, as the observer reported that the gauge had overflowed at the 9am reading. A Bureau pluviograph a few kilometres away registered 376mm for this period.

For details of all heavy falls, go to the AWN pages for 9 March, 10 March and 11 March.

The general flood situation

Major flooding, bringing widespread inundation and dislocation of services, occurred in the lower Clarence, upper and lower Macleay, the upper Hastings rivers and the length of the Bellinger. Moderate flooding occurred in parts of all other systems from the Manning at Taree north to the Richmond at Coraki and Wilson at Lismore. Details of flood peaks are given on the AWN pages for 9 March, 10 March and 11 March.

Both main river and local flooding progressively cut the region's only through route, the Pacific Highway, in more and more places on Friday. During the morning it was closed by floods north and south of Grafton, and by a jack-knifed truck and fallen tree south of Urunga. Later in the day, the highway was also closed at Taree, Kempsey and Macksville. Secondary roads throughout the region were impassable with low-level bridges under water, downed trees, washaways, and sheet and runoff flooding. Rail services were suspended. By Sunday, the Pacific Highway was closed to all but local traffic between Taree and Coffs Harbour, and as of Wednesday 14 March it was still cut at Kempsey and south of Ballina, though detours were available.

Emergency workers used helicopters and boats to evacuate or supply isolated homes. By Sunday, additional helicopters had been brought in from State Forests, Northpower, the National Park Service, the Australian Navy and Westpac Rescue and private operators to keep up with the food drops and medical evacuations needed. The whole Bellinger Valley was isolated, as were scores of small communities west of Coffs Harbour, and around Kempsey, Port Macquarie and Taree.

Thousands of people were without power after Thursday night's strong winds brought down trees onto powerlines and substations were affected by flooding. The region's main city, Coffs Harbour, sustained widespread damage to trees and powerlines. A man was injured when a tree fell on his tent south of Iluka.

The flood situation, river by river

Richmond: Lismore, which suffered major flooding a month ago, recorded moderate flood levels with no damage reported. In the lower Richmond Valley downstream from Coraki major flooding isolated farm properties in the Bungawalbyn and Tabbimobile areas.

Clarence: By late Saturday afternoon, the SES began evacuation of the entire northern section of the city, worried by a forecast flood peak initially of 8.1m revised downwards to 8m, to occur midnight Saturday night. The record flood level for Grafton was 7.90m set in 1890. The city's flood levee system, built in the late 60s and early 70s  had never been tested by a flood of this height. The plan was to move more than 10,000 people from Grafton and Ulmarra to Coffs Harbour by train. Nursing home residents and patients from Grafton Base Hospital were taken by bus and ambulance to Casino, 80km north. One train of about 500 evacuees left for Coffs Harbour on Saturday evening, and an estimated 2000 people in all were evacuated from the city. Police sealed off the city to the north and south late Saturday. However, when the flood level evened out at 7.67m during the evening, evacuation was suspended and everyone held their breath, hoping it had peaked. It rose a further 8cm to peak at 7.75m at 10pm Saturday. Most people in Grafton subsequently returned to their homes on Monday.

The focus now shifted to the downstream towns of Ulmarra, Maclean and Yamba where the river was expected to peak on Sunday. Forty elderly people were evacuated from Ulmarra on Saturday afternoon, while the remainder of the town's population of 470 was evacuated later on Saturday. Three hundred people were evacuated from Maclean on Saturday, with a further 400 expected to be evacuated Sunday. Two caravan parks at Maclean were cleared. About 200 homes between Maclean and the coast at Yamba were threatened, and sandbagging was in progress at Yamba.

Bellinger: Major flooding continued on Friday. Some evacuations were carried out at the eastern end of Bellingen and from villages to the west, while food drops were made to the outlying communities at Kalang and Darkwood. With Bellingen itself isolated, the SES brought 3000 litres of milk for the town by flood boat early Saturday morning. The heights reached by the flood peak are not clear, with autographic equipment failures placing reliance on manual gauge reading. ABC news stated that the river reached 8.6m at Bellingen, the highest since 1974, and 8.0m at Thora, the highest since 1953.

Receding floodwaters on Monday revealed that three bridges in Upper Bellinger valley above Thora had been washed away. About 1000 people live in the valley, and the damage is expected to take months to repair. Lack of access also made restoration of basic services, such as phone and power, difficult.

Nambucca: Sandbagging began on Friday as the heavy overnight rain in the catchment forced flood predictions higher, and authorities were at one stage reported to be considering evacuating the town of Macksville, much of which is on the floodplain. However, the river peaked at Macksville Friday evening with moderate flooding.

Macleay: Emergency controllers became concerned late Friday when it became clear the river would exceed the forecast 5.2m peak, flooding scores of additional properties on the surrounding floodplain. An evacuation alert was issued for people to leave while access roads were open. Hundreds of families were moved to Kempsey's two high schools. SES volunteers and townspeople spent much of the day sandbagging businesses and raising goods. As the river reached 6.3m early Saturday morning, floodwaters breached the town's levee system for the first time since 1963, forcing evacuation of the central business district. The river at this time was expected to peak at 6.5m at noon Saturday, later revised to 6.7m/8pm Saturday, then to 6.9m/late Saturday evening. By late evening, the river was at 7.2m and still rising slowly, with most of the town's 30,000 residents isolated. The river peaked at 7.8m early Sunday morning, making it the worst flood in Kempsey since 1949.

About 100 people were evacuated from the Mirriwina Gardens settlement 50km northwest of Kempsey on Saturday, while evacuation began of the floodplain villages of Smithtown and Gladstone, downstream of Kempsey, to South West Rocks. Sixteen helicopters were involved in the evacuation and in making food drops in the Macleay Valley. However, because Kempsey was now isolated, the town itself was running out of basics. On Monday, plans were made for a further 600 residents to be evacuated from Smithtown and Gladstone to South West Rocks as raw sewage leaking into floodwaters sparked a health scare. However, only about 100 evacuated, the others wanting to stay and prepare for the clean-up.

A search began for a missing canoeist on the flooded Styx River in the upper Macleay catchment on Friday after a rescue attempt resulted in a 4WD being swept away by floodwaters. The driver and a second canoeist raised the alarm. The result of the search is not known.

Hastings: Two flood peaks moved down the Hastings, one on Friday morning and a second larger one on Saturday. While major flood levels were briefly reached in the upper Hastings, which appears to have provided most of the flow, these had diminished to moderate levels at Wauchope and minor levels in tidal areas. However, flows were still strong enough to force suspension of the Hastings River ferry at Port Macquarie.

Manning: A moderate flood peak moved down the lower Manning Friday. There were no press reports of damage.

Paterson and Hunter: Although major flooding occurred in the Paterson River and moderate flooding in the Williams, levees held and no homes were threatened. Large areas of farmland were inundated and several roads closed in the Maitland to Paterson area. The Hunter River experienced only minor flooding in the lower reaches just above minor flood level at Maitland.

The aftermath

The natural disaster declaration, paving the way for joint state/federal loans and hardship assistance to councils, residents, farmers and businesses, was extended on Friday to cover the whole North Coast from Taree and the Manning River north to the Richmond River. The NSW Premier, Bob Carr, visited Grafton and Kempsey on Sunday, and praised SES workers, especially those that had the unenviable task of deciding whether or not to evacuate Grafton. The Deputy Prime Minister, John Anderson, toured the area on Tuesday, and assured the community that the Federal Government would meet any shortfalls in funding.

A State Government taskforce, set up to streamline government response to the flood disaster, met on Tuesday to work out strategies for assisting flood victims. Damage and immediate needs are being assessed, with the most urgent being food, fresh water, sewage disposal, and temporary housing for those whose homes have been inundated or damaged.

Inspections of the Macleay and Richmond rivers following the flooding led the NSW Fisheries Department to close both rivers to recreational and commercial fishing for a month, as low oxygen levels caused by decaying vegetation have caused large fish kills. Thousands of dead fish were reported washed up on beaches at South West Rocks, at the mouth of the Macleay NE of Kempsey.

The Nature Conservation Council issued a statement blaming upper catchment clearing and disturbance of floodplains and wetlands for heightening the impact of the flooding. The Council's Catherine Ridge was quoted by ABC News as saying "Because we've been clearing the upper catchment, what we've done is exacerbate the impacts of flooding, so the same amount of water in our rain or flood events is now causing a greater effect downstream in the river system, because of the way we've used our catchments."

Press and political questions were raised as to why the Bureau of Meteorology had not tracked Thursday's damaging low pressure system as it would have a cyclone. As reported in AWN for Thursday, the system exhibited all the characteristics of a category 1 or 2 cyclone, except that it lacked a tropical origin. Ballina MP Don Page pressed for an overhaul of the BoM's classification of severe weather events. He was quoted by the ABC as saying that, had the system developed in tropical waters, it would have been classified as a cyclone, and its strength and movement more closely monitored.