RECOVERY AFTER a NATURAL DISASTER 04 April 2014
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RECOVERY AFTER A NATURAL DISASTER 04 April 2014 FMA Conference-May 2014 “Of Utes and Flooding Rains” RECOVERY AFTER A NATURAL DISASTER Executive Summary Northern Grampians Shire is situated at Western Victoria around 230 km from Melbourne along western highway. Geographically, it covers around 5,918 Sq.km of area. It consists of Stawell and St Arnaud as its major town ships and Great Western, Halls Gap, Navarre, Marnoo and Stuart Mill as its sub towns. It has a total population of 11,942 people. Stawell itself accommodates around 6000 people and St. Arnaud houses for nearly 3500 people and rest of population is spread all over the shire. Recently, there were a couple of successive major storms swept through most of the areas of the shire. More than 90% of the shire’s infrastructure was badly affected by the consecutive floods in September 2010 and January 2011 Floods. The devastations were mainly caused by the over spilling of the main rivers and streams which are running across the shire. (Refer Fig. 01) The catastrophe was considered as urgent, so immediate and long term plans and actions have been taken to mitigate the effects of the damages to the community and the shire as a whole. Fig.01- Major Streams & Rivers Running Across the Shire Origin of the Disaster The Northern Grampians Shire was severely impacted during September 2010 flood. Major rivers which are running across the shire such as Wimmera, Avon, Avoca and Richardson brought huge amount of water into the Northern Grampians region. The second flood on January 2011 was caused by around 270 mm (10.8 inches) of rain, recorded at the Mt William weather station over the 72 hours of 12-14 January 2011. So the intensity of the storm is very high. This was due to the fact that the entire shire terrain was already saturated with rain water due to the September 2010 flood and the terrain itself has low permeability at most of the areas in the shire. Lower permeability of the terrain coupled with high intensity of the rain, made it worse for the rain water to infiltrate through the ground surface which in turn created many flash floods in several areas of the shire. So that, Council’s road infrastructure network was severely impacted by the floods, with damage recorded at 1,707 individual locations. (Refer Fig.02). Fig.02-Locations Depicting the Flood Damages Areas of Damage All most all parts of the shire were affected by the devastating flood. The initial estimate showed that the flood caused around 20 Million worth of damage for the entire shire infrastructure. The damages shall be divided into following categories. 1. Shire Infrastructure 2. Private Properties 3. Areas belongs to other Authorities Shire Infrastructure The flood swept away most of the shire infrastructure and caused severe deterioration to them. The followings were the common infrastructures impacted by the catastrophe. Road Networks The Roads asset group, totalling 3,481 km of roads under council jurisdiction based on the Council’s Road Management Plan 2013. It contains 738 km of bitumen sealed pavements; 2,203 km of unsealed pavement; 470 km of formed roads (no gravelling or sealing); 157 km of kerb & channel; and 105 km of footpaths. Council Roads are further classified into Urban and Rural under the sub classification of Link Roads, Collector Roads, Residential Access Roads and Property Access Roads. Nearly 90 % of the road network was damaged due to the flood. Gravel roads with form tracks were the major prey for the flood waters. Most of the gravel roads were eaten away and the table drains with cut off drains were also ruined by the flood water. So the drainage structures for the roads were very badly damaged and the water started to stagnate everywhere on the roads and thus made them impassable by the public. Sealed roads were also undermined by the flood water and the bitumen seal were lifted off in several locations along the roads due to the high velocity of flood water. Bridges and Culverts According to the Council Service Asset Management Plan for Bridges and Major Culverts, Council has the responsibility to maintain around 533 Bridge & Major Culvert Structures. Most of the Bridges and Flood ways across the major rivers and creeks had gone under the water. The batters and water ways of most of the water way structures were scoured very badly. Water ways were blocked by debris and silt which were brought by the flood and thus reduced the capacity of the water way area across the road; this in turn inundates the roads across those Bridges. Decking and abutments Page 3 of 22 were undermined and scoured severely. In some locations, culvert pipes were pulled apart due to the huge force of the flood water. Drainage Pipes and Pits Council is accounted for the maintenance of around 59km of drainage pipes and 2,296 numbers of drainage based on the Council Asset Management Plan. Drainage pipes and pits over flowed because of the incapacity of those structures to cater for that big storm event. Pit Lids were lifted off and taken away by the massive force of flood water. In some of the locations, pipes and pits were undermined and pulled apart and thus made the structures to lose their key functionality. Buildings Council holds the responsibility for around 149 nos of building according to the Council Asset Management Service Plan for Buildings including halls, libraries, community centres, public toilets and community hubs. Some of the halls in the rural area were flooded with water. The dampness decayed the timber structures of the buildings and made the foundation weak. Once the flood water had receded, most of the buildings were found, filling with debris and silts. And for the worse case, some of them swayed aside to a certain degree which in turn prevented the buildings from using them for their intended purpose. Kerb & Channel (K&C) and Foot path There are around 145km of K&C and 102 km of Foot Paths under the Council Asset Register. Foot paths are again classified based on the construction material such as concrete, seal and gravel. Some of the concrete footpaths were undermined and sealed foot paths were lifted off and gravel foot paths were scoured and washed away by the roaring flood waters. K&C were undermined and lifted off in some of the area where the flood action was very severe. Parks & Garden It includes Parks, Recreation Reserves, Playgrounds and Trees. Some of the soft fall areas were scoured and washed off by the flood. Even in some areas, park furniture and garden beds were washed away. Trees were uprooted in several locations especially in urban areas. Because of that, the general transport through the areas or roads was temporarily ceased and it was cost a lot to remove those fallen trees across Page 4 of 22 the transport routes immediately in order to implement the immediate flood recovery activities. Private Properties The damage to the private properties are analysed in to two categories such as Households & Farm Lands and Life Stocks. Households and Farm Lands These properties mainly include farm lands, fences, crops, houses and sheds of private people not owned by the Council. Even after the flood, it was observable in most of the farm lands that the fences were leaned to one side due to the debris trapped between barbed wires and fence posts were scoured and uprooted. In some areas, fences were totally washed away from the properties. Crops were uprooted and washed away which made immense lost to the farmers. Houses and sheds were inundated and the properties inside the houses were damped, rotted and even in some areas those were washed away. Live Stocks Sheep, Cattles, Poultries and Piggeries were affected by flood under this category. Their shelters were damaged or washed away and their staple food like hay bales and stock foods were washed away and grazing land were covered by flood water. Most of them were left unattended as refugees. They suffered from starvation and diseases and most of them eventually died. Even, some of them were washed away by the flood. This one made a great impact on the farmers’ economy. Areas belongs to other authorities Most of the river basin and creeks are belongs to Catchment Management Authority (CMA). So these stream beds and embankments were scoured severely and washed away by the flood water. And the water ways was blocked with debris in several locations. Some of the Roads and Bridges or Culverts and channels in the shire are belongs to Vic Roads and Grampians Wimmera Mallee Water (GWMW) Authority. These assets were also very badly affected by flood as to the same degree as for the shire’s infrastructure. Page 5 of 22 Some of the roads through the Department of Sustainability and Environment (DSE) land are belong to DSE. These were also badly affected by the flood. Actions taken by Council In order to mitigate the adverse impacts caused by the calamity, Council took immediate steps as well as long term actions with the careful planning and considerations. Immediate Actions • Worked in collaboration with State Emergency Services (SES) in order to save the people those who were surrounded by flood water especially in rural areas. • With the help of other Service Organisations, arranged temporary shelter facilities, food and other basic facilities for the community whose households were swept away or deluged by flood. • Deployed the depot crews to inspect the bridges, culverts and flood ways in the roads especially which are more prone to go under flood water and to install temporary signage for those impassable roads in a way to warn the community not to use those inundated roads for safety reasons.