Flooding in Melbourne City

Flooding happens when rain or waterway water floods in a zone with poor drainage. The channels in which the water flows are filled with water such that there is no good drainage of water. The floods happen if a tidal wave comes across the sea, therefore, causing the sea or the ocean water to flow to the dry land.

            Almost all floods are unsurprising before occurring, along these lines giving the objective individuals the adequate amount of time to relocate or repair the seepage frameworks. Nonetheless, flooding of a dam is capricious in this way greatly hazardous. Dam floods or breaking clears everything on the land hence the most perilous sort of flood. Floods are classified according to the likelihood of happening in a given time. Floods which take a long time to happen are most dangerous[1]. They happen once per one hundred years. Practically they have a probability of about one percent happening. The occurrence of floods in Melbourne city happens seasonally according to the data provided by the meteorological department.

             The amount of rain is estimated by use of the rainfall measurements. Rainfall is measured by use of rain gauge in mm. Amount of rainwater in an area is estimated by checking the measurements of the rainfall intensity. The estimation process needs time and rainfall quantity parameters. The chosen city is Melbourne city and the suburb areas. The variables include time and rainfall measurements given by the rain gauge. The volume of collected water in the rain gauge is given by the formula: (depth x diameter x diameter x 3.142/4). The depth of rain gauge measurements is given in the data as 16.2mm. The standard diameter for rain gauge calibration is 20mm. the volume for water collected in the rain gauge is thus (16.2*20*20*3.142/4)= 5090.04 ml. Let’s work with an estimation of one-hour rainfall duration.  The estimated area of Melbourne City is 36 sq. Kilometers. The amount of rain is thus 5090.04*4*(36*10000*10000)/ (3.142*20*20) = 9.1333*10^9 cubic meters of water.

            The water goes to the rivers and natural water collection bodies such as dams and lakes. The water forms a small channel along the footpaths and roads.  The water in Melbourne City is tapped into tanks and water storage weirs. The water is tapped through gutters and directed to the tanks.

            The amount of water that goes directly to the earth is a function of the water collection and number of rivers. The water that goes to the earth is approximately 80% of the total rainfall. Melbourne city has a high number of water catchment areas hence the quantity of water that goes back to the earth is approximately 60%. In suburb regions, the amount of water that drains into the earth is approximately over 80% due to the low number of tanks and weirs. The amount of water that goes to the gutters and drains into the sea is approximately 20%. Most of the rainwater goes back to the earth. The quantity of water that drains into the sea from Melbourne city is approximately 25%. The town has several man-made channels which direct the water into seas and lakes. Flooding across the rivers occurs during the rainy season when the water flows over the banks[2].  Such floods are experienced in the larger rivers. For example, flooding has been occurring in the Melbourne valley for long time affecting agriculture and construction industry. When a river overflows and the water flows through the inland, most of the structures and poorly constructed buildings are eroded and destroyed. The enormous waterways and the trees developing around are cleared away.

Collected and Reused Water

            The amount of water collected depends on the number of tanks and water collection structures.  Water is collected via the gutters and directed to the tanks by use of pipes. Most of the collection facilities have the good network to direct the water into collection points. Melbourne city has a high number of collection tanks. From the above description, the amount of the water collected is 20% of the total quantity. The expression below shows the calculation: 20% * 9.1333*10^9 cubic meters of water.

            The water is re-used in doing some domestic activities such as washing and watering plants. Water is re-used mostly in suburbs than in the city. Residents in Melbourne city do not re-use water because they have an adequate supply of piped water unlike in the suburbs where there is a water shortage. Sometimes the water is purified to be fit for human consumption. Purification process happens in water treatment plants to kill the germs and clean the water. Melbourne city residents prefer re-using water rather than purifying because it consumes large amounts of energy and time to treat rainwater. Grey water is highly re-used compared to drinking water. Drinking water must be purified before it is re-used.

Why Certain Locations (Roads Or Buildings) Are Prone To Flooding?

            Some locations are prone to floods due to the topography and type of soil in the region. Flooding happens due to the inability of water to drain.  If the soil has poor drainage, the rate of water seepage is low hence flooding occurs. Again some places have flat topography. The flat region prevents water from flowing freely through gravity. Such regions lack channels where water can flow through.

Figure 1: Melbourne City

            Some of the buildings are situated in swampy areas without proper drainage. Again, the roads with poor drainage are affected by floods. Such roads are built on soil with poor drainage and they are flat. Such roads are found in the outskirts of the town. Buildings without proper foundation are prone to flooding.  Such places occur in places without raised foundations. Such foundations require an approximately high amount of ballast to raise the structures.

Size of Drains

            There are no rivers within the central business district in Melbourne City.     The city has drainage systems to direct water into channels and rivers. The volume of surface runoff water is high in places with large buildings as compared to the outskirts.

            Weirs are used to regulate the flow of rivers and open flow channels. In some of the applications, the level of water in the weirs is used to determine the discharge at the downstream. The notches are either V-shaped or rectangular. Some notches have sharp edges so that the water springs clear the plates as it passes through the notch. The V-shaped notches are supplied with angles of 15 and 45 respectively. A contraction section leads the water to a short channel, into which either the rectangular or V-notched weir plate may be fitted. Water flows over the notch and is collected over the exit tank. The outlet leads via a drain port to the weigh tank of the hydraulic bench.

            The size of drains depends on the terrain and number of buildings in the area. A flat region has the high number of channels to drain water away as compared to sloppy area. Buildings increase the amount of runoff water. Some of the water channels direct water from the gutters to rivers. Therefore, places which have a high number of buildings have huge water drainage systems[3]. The channels are either rectangular or V-shaped.  The rate of water discharge from the channels depends on the slope and the number of buildings around. The high the number of buildings the high the volume of runoff water. The drainage systems should be built in places with a high number of buildings ad flat regions. The drainage system should have good layout and distributaries which bring water to the main channels. Some of the distributaries should collect water from buildings and direct to the sewage reservoirs.

The Impact Caused By the Train Cancellations

            Train cancellations lead to congestion and delay in dispatch of goods in various places. Most of the train passengers are business people. The number of businesses that come on hold during floods increases by 20%. The distribution of goods in the city is affected. Perishable goods expire before they reach customers. The general consequence is decline entrepreneurial activities. Most the business people use trains to travel in different places to distribute goods and deliver services[4]. The halt of business activities leads to a decrease in the economy.  Melbourne city should construct good drainage systems to minimize train cancellations which bring the city into a halt.

Bibliography

Aubrey, Carol. Mathematics teaching in the early years: an investigation of teachers’ subject knowledge. Routledge, 2013.

Halpern, Diane F. Thought and knowledge: An introduction to critical thinking. Psychology Press, 2013.

Lesh, Richard A., and Susan J. Lamon, eds. Assessment of authentic performance in school mathematics. Routledge, 2013.

Saxe, Geoffrey B. Culture and cognitive development: Studies in mathematical understanding. Psychology Press, 2015.

[1] Aubrey, Carol. Mathematics teaching in the early years: an investigation of teachers’ subject knowledge. Routledge, 2013.

[2] Halpern, Diane F. Thought and knowledge: An introduction to critical thinking. Psychology Press, 2013.

[3] Lesh, Richard A., and Susan J. Lamon, eds. Assessment of authentic performance in school mathematics. Routledge, 2013.

[4] Saxe, Geoffrey B. Culture and cognitive development: Studies in mathematical understanding. Psychology Press, 2015.