Understanding of Flooding and Major Floods in Melbourne - Assignment Example

Executive summary The aim of this paper is to enhance the understanding of flooding and its impacts by analysing major floods in Melbourne. Flooding is defined as the situation when water overflows and floods areas that are normally supposed to be dry and without water. In the current application and in urban areas, the covering of water is seen to submerge buildings and other infrastructure, resulting to damage and destruction of property and lives. In some cases, water could be flowing from existing water bodies such as rivers, lakes, and even oceans. However, in other cases, flooding can be caused by blockages of drainage systems. Consequently, during the rainy seasons, water flow is compromised leading to flooding. The effects of flooding vary depending on the area in which the flooding is occurring. These effects include destruction of property, loss of life, and injuries. Other effects include displacement of people and businesses, reduction in the mobility of people in the region thereby inhibiting movement, transport, and other uses for infrastructure. The report finally, analyses the recommendations that should be followed in a bid to manage flooding. The report targets the flooding that is brought about by natural events as well as those to which manmade features have contributed. Introduction Floods are common, and they differ in impact and length. Some are short lived but have huge impacts in terms of lost lives, injuries and property damage while others take time before water dries up. A flood is a temporary phenomenon that is caused by extreme, wet weather conditions that cause rapidly unusual accumulation of runoff water in great amounts thus partially or completely covering an area of land that usually is not covered by water (Wake, 2013). A flood plain is an area/land that is vastly flat in nature on either sides or both sides of a river that normally/frequently floods when the river overruns/overflows from its usual course of channel (Wake, 2013). There are different types of flooding; however, river flooding is the most common and frequent one. Each type of flood has different causes including heavy rainfall, coastal storm surges, high tide, high wind cyclones, tsunamis, high tide, dam failure, and earthquakes. Australia is generally divided into four major topographical areas: the great western plateau, the eastern highlands, the lowly sandy coastal plain and the central plains. The coastal plains have the most frequent incidences recorded in history (Wake, 2013). Flooding in the flat inland regions of Australia may cover thousands of square kilometers of land and may take up to several weeks to drain. Floods are often devastating. However, they have few positive impacts. Regions suffering from long extensive periods of drought, for example,somehow benefit when floods hit their regions. Farmers can harvest floodwater and use it to irrigate their land and crops during the dry season and provide drinking and household water as well.Floods help in redistributing and returning rich sediment that is enriched with nutrients to the soil and thus replenishing wetlands with those nutrients (Wake, 2013). Natural debris that is carried along with floodwater help to offer natural habitats to organisms living in rivers. Flooded soil receives extra fertility thus allowing new vegetation to grow especially on riverbanks. However, the negative impacts of flooding seem to overwhelm the positive ones and thus the need to focus and emphasize more on them. Every year, there never lacks a region in Australia that floods and this has resulted in millions of dollars lost in terms of damages to property, crops, animals, infrastructure and loss of lives. The average annual cost of damages between the years 1967 to 2005 is estimated to be a whooping A$377million (Middelmann-Fernandes, 2010, p. 89). The year 1974 was the most costly at A$2.9 billion when cyclone Wanda in Brisbane caused 16 human deaths, over 300 injuries, and over 9000 homes destroyed amongst other types of damages to businesses, and infrastructure(Middelmann-Fernandes, 2010, p. 89). Due to the extensive damages caused by floods, the Australian government introduced standard definition of flood in the interest of insurance purposes. It was therefore defined as “The covering of normally dry land by water that has escaped or been released from the normal confines of: any lake, or river, creek or other natural watercourse, whether or not altered or modified: or any reservoir, canal, or dam”(Carter, 2012, p. 1). This definition will hold, be used and apply when an insurer offers a flood cover to an individual or company. Experts in climate changes predict that severe weather conditions and global warming will continue to change and increase the extreme effect in just but a few decades ahead. Therefore, it is expected that incidence of flooding will increase in frequency and magnitude. Urban development is grossly on the rise as Australia’s and the world population increases. This creates a need for flood risk assessment and awareness. An analysis of data from previous floods is required in a bid to assess, predict, prevent, and manage floods when and if they do occur. This strategy will help in preventing or reducing damages and loss of lives. Types of floods Floods differ with impact, occurrence, and the type and extent of damage that it causes. The three main types include coastal surge, fluvial (river flood), and pluvial flood (surface flood), all which are common and frequent in Australia(Pittock et al., 2006). Coastal Surge Flood As the name implies, costal surge floods occur in coastal, low-lying areas near or aroundthe ocean, sea,and lakes. Severe weather conditions manufacture extremely huge types of tidal waves that in turn cause the flooding when they hit the shores. Extremely high winds from raining storms in the water or hurricane cyclones carry huge loads of water onshore thus causing the flooding. This type of flooding is the leading type of flooding in coastal regions. Flat and low-lying coastal areas/land become overwhelmed by the water and become flooded thus causing a great extent of damage to property, crops and loss of lives. Coastal flooding can also be as a result of underwater earthquakes that are of great magnitude in nature, underwater volcanic eruptions, man-made underwater explosions, by falling glaciers, landslides, falling meteorites and any other underwater and/or above water displacements. All these phenomenon cause a very gigantic wave of water called a tsunami. Also known as a seismic wave, a tsunami is a series of water tidal waves inside a large water body that is brought about by the displacement of large volumes of water. The waves usually vary in the time they take to get to shore; varying from minutes to even hours. Their wavelength reaches tens of meters and though limited to coastal regions, the extent of their reach and damage sometimes covers entire ocean basins (Pittock et al., 2006). Coastal flooding has three basic levels of categorization: i. Minor: Flooding that covers over a small area of coastal land resulting into minimal amount of erosion of the beach as well as minimal damage to property, crops and lives. ii. Moderate: In this instance, flooding occurs over a large area of coastal land resulting in average damage to property, crops, and lives and mild/moderate amount of beach erosion takes place. The threat to life and infrastructure is not very huge and can be contained or managed. iii. Major: Flooding occurs over a vast area of coastal land leading to very serious damage to property, crops, infrastructure, and imminent threat to life. Safety of life should be regarded first and necessary precautions put in place including evacuation of people if necessary (Pittock et al., 2006). The severity and extent of flooding in coastal regions is directly dependent on factors such as wind strength, its speed, direction, and size of the storm. Topography onshore and offshore also determines the extent of flooding that will take place. Collection of this data is crucial in determining the extent or magnitude of a coastal flood and how probable it is to happen. This and data from past floods in the same area and areas similar to it are crucial in creating coastal flood models that can be used to predict, manage and resolve coastal flooding. Fluvial (River flood) It is caused by excessive rainfall over a considerable amount of time. Surface runoff gets into a river such that the latter has an excess amount of water exceeding its holding capacity. Consequently, there is overflow over its banks, which floods land on either or both sides of the river. It can also occur due to huge amount of snow melting upriver thus causing an excess amount of water to flow downstream and overwhelm its holding capacity leading to flooding of the low-lying flat areas below. The overflow of water affects other rivers and streams further downstream causing widespread massive damage, which causes dams and dikes to break and over flooding swampy areas (Pittock et al., 2006). Riverine flooding categorized into two major types: i. Overbank flooding: water gradually increases in a river over time rising above the edge and overflow onto the low-lying land around it and eventually flooding it. This can occur in any type and size of river channel and streams and is the most common type of riverline flooding (Pittock et al., 2006). ii. Flash flooding: Occurs very rapidly without any notice at all. This is as a result of large, intense, and high velocity movement of water in an already existing river channel. This is caused by heavy rainfall or ice melting further up the river or valley, which causes massive and abrupt increase of water content forcing it to move down stream at very high speeds due to the force from the intense quantity of water. Flash floods are extremely dangerous because they occur without any notice. They usually find people unpreparedleading to huge losses, and deaths. In addition, fast flowing water carries stones, trees, cars, and other material alongside, which add to the destructive nature of flash floods. Moreover, this material block water channels leading to further flooding (Pittock et al., 2006). Riverine flooding is highly dependent of the amount of rainfall in an area, duration of rainfall, type of saturation of the soil in the area and the surrounding topographical terrain around the river. In low-lying and flat areas, water flood rises slowly, spreads out vastly to form a shallow flood, which in most cases remains stagnant for days and takes a while to drain. In highly mountainous and hilly areas, floodwater rises quickly and can occur within minutes after a heavy rainfall. Water does not spread out vastly rather accumulates in a smaller area and drains soon after (Pittock et al., 2006). Similar to coastal flooding, fluvial flooding can be predicted and managed using previous flooding data in the region with the addition of soil precipitation samples, topographical terrain data, river water levels and forecasted temperatures and rainfall. Pluvial/Surface flooding In this type of flooding, heavy downpour creates the flood independent of any water body and flowing water. It occurs in any types of topographical terrain. It is categorized into pluvial flooding from intense rainfall and pluvial flooding from runoff. In the former type, heavy rainfall overwhelms and saturates soil and drainage systems of an area forcing water to overflow onto streets and nearby structures thus causing flooding. The second subtype is pluvial flooding from run-off of rainwater from hillsides. Heavy rainfall uphill may overwhelm the hillsides leaving them unable to absorb the excess water causing it to overflow to the surrounding areas on the hillside. The most commonly affected areas are hillsides that suffered from recent forest fires (Pittock et al., 2006). Most of the time, pluvial flooding takes place in combination with fluvial and coastal flooding. It rarely goes beyond a few centimeters depth of floodwater but still it can cause great extent of damage (Pittock et al., 2006). Other man-made structure such as faulty/poorly built dams that hold large volumes of water may cause massive flooding and extreme damage to property, crops and massive loss of lives when they give in to the overwhelming weight of the water they hold. In such a scenario, they release it all at once flooding the area below. Urban Flooding In urban or developed areas, flooding is experienced in a slightly different way than those in other areas. The main aspects that are involved in the flooding of urban areas include primarily the presence of poor drainage systems. This indicates that in urban areas, the urban areas are the designated pathways for water that comes from rainfall. However, in some cases, the rain becomes too much and overwhelms the designated drainage system overflowing onto the surface. This results to the onset of flooding as the intensity of rain increases. In other cases, due to poor management and standards, in the urban areas, these drainage pathways areblocked by trash and poorly disposed items such as plastic containers. When it rains, the water, which should effectively run through these drainage pathways, fails to find these paths and thus overruns streets or surfaces. When this happens, infrastructure such as roads and electricity grid becomes overwhelmed and in other cases, it is destroyed completely. Due to the high population in the urban areas, the devastation that is caused by flooding per square mile might be more than that in other areas. However, the infrastructure and houses that are destroyed in the urban areas are the equivalent to the vegetation and homes that can be destroyed by river flooding in sparsely populated areas. Aim of this assignment The report intends to look at the flooding situation in Australia. The main reason for this is to understand the flooding incidences that have been witnessed in the country. The report undertakes to look at the areas that have faced severe flooding, scrutinize the possible reasons for the extensive flooding, and finally attempt to find out what can be done to stop or reduce flooding. The situation in Australia is unique and rendered intense because of the increased incidences that have been witnessed especially in the past century. The report also aims at the establishment of general and specific factors that are responsible for the high incidence of flooding in the country. This is done through the scrutiny of a number of reports and secondary data that have information about flooding in Australia. Intriguingly, there are areas that have been seen to be prone to flooding, and others that have been seen to not have any flooding incidences. Further, there are areas and flooding incidences that experience extreme flooding condition compared to the rest of the country. Even within the areas that are seen to be highly prone to flooding, there are those that seem to be safe from flooding. The specific features present in the areas that are prone to flooding, are also scrutinized in order to ensure that it is possible to find out if they are natural or manmade. Finally, the report will show the beast approach to reduce the impact of flooding especially in places where it is almost inevitable. This includes prevention of loss of lives and the destruction of property. Methodology Research is carrying out a diligent inquiry or a critical examination of a given phenomenon. It involves a critical analysis of existing conclusions or theories with regard to newly discovered facts. This means that it is a continued search for new knowledge and understanding of the world around us. Research is a process of arriving at effective solutions to problems through systematic collection, analysis and interpretation of data. This study uses a descriptive survey. A descriptive survey is essential in describing the characteristics of existing phenomenon in soliciting information flooding casesin Australia and its effects on decision-making process as far as the policies against future flooding are concerned. Descriptive survey design is used since it provides insights into the research problem by describing the variables of interest. It is used for defining, estimating, predicting, and examining associative relationships. This helps in providing useful and accurate information to answer the questions based on who, what, when, and how. Correlation research is used to relate events that have occurred in the past to current events. It also enables the researcher to relate the research problem to the missing gaps of other research work,which have been covered and show what the other researchers overlooked possibly due to time differences or economics and social factors. The target population is the two main cities in Australia, Melbourne, and Sydney. Since it is impossible to study the whole of the target population, the researcher has identified and defined an experimentally accessible population also referred to as survey population. The scientific process is used to provide rationale and identify accessible population based on consistency and not convenience. During this research, the researcher will take note of the ethical considerations as expressed above. This means that data and information will not be misrepresented to influence and impactthat research and the direction that the research is meant to take. The scrutiny of Melbourne and Sydney cities will be essential in the management of the data and information that is collected from the secondary sources and it will bring in a sense of direction because of the reduced or narrowed down focus in the research. It is easier to work with narrowed down results and reach recommendations and conclusions that can be linked to a region as opposed to general recommendations. Conclusion The relationships between two or more variables can usually take several forms. These forms are used to explain and portray the direction in which the relationship is skewed and in essence, form the nature of the relationship. Among the relationships that can exist between two or more variables, there could simply a correlation. Correlation means that the variables are related. The paper shows that while there were a myriad of incidences in Melbourne and Sydney in Australia, the problems might lie in people of the regions and their habits as opposed to begin purely natural events. According to Carbone and Hanson (2012), the destructions that flooding incidences in Australia experience are brought about by the contribution in part of the people in the regions, who are intent on building in the path of water and floods. They further argue that regardless of history of the flooding incidences, which have been many in the country, the management of the regions has allowed human and animal populations to swell in areas that are considered low-lying floodplains, or areas that are simply prone to flooding. However, there are commendation that the Australian authorities are keen and active as far as managing and handling such emergencies is concerned. However, there is need to have solutions that are more permanent and the proactive approaches to manage the incidences as they arise. He also warns that this is not strictly in the cases of flooding, but all natural disasters that have been witnessed in Australia .Floods are increasingly causing damages and havoc in the Australian agriculture and infrastructure, and as experienced in the past, they have been fatal. However, they are observed to also increase and assist in some major parts and aspects of the natural cycles. They play a huge part in distributing seeds, sediments to new areas. Dangerous floods have occurred in every Australian state over the last 150 years. References Wake, B., 2013. Flooding costs. Nature Climate Change, 3(9), pp.778–778. Available at: http://www.nature.com/doifinder/10.1038/nclimate1997. Read More