The Essay On Impact Of Paved Surfaces On Flash Floods In Urban Areas.

Causes of Flash Floods and Storm Runoffs

The green spaces in urban areas are slowly being replaced with car parking lots and walking pavements. This has led to an increase in flash floods and huge amounts of surface runoff. The increase in surface area of waterproof surfaces such as the car parks and walking pavements has greatly reduced the amount of water that seeps in to the ground through the soil leading to an increase in the amounts of water that move as surface runoff. This has become a major cause of storm runoffs and flash floods. With the continued rise in population, there is more need for housing a better facility as well as more vehicles being bought by the people. This means that the green surface faces increased risk of depletion especially in urban areas and hence more flash floods and more storm runoffs. It is for this reason that more research should be done in order to assess the exact situation and help in decision making and policy making to improve the human lives as well as maintain a good environment in our urban areas. In Leicester, United Kingdom, there have been a rise in the number of floods that are experienced in the area (Mack and Bedford, 2021). The floods are so strong that they sometimes cause the closure of roads and flooding of hospitals as well as homes and hospitals. It should be noted that Leicester has more than 8,500 spaces for parking within the city center alone whole it also has 1,500 parking spaces at the park and ride schemes which are three. An average parking space has an area of 16.7 square meters. this means Leicester has a total parking space area of averagely 167000 square meters. This area is approximately 2.3% of the total city area which is a high risk for the city especially considering the high amounts of floods that it experiences. Leicester experiences a climate that is classified by the Köppen-Geiger system as Cfb (Wikipedia Contributors, 2019). Here, even during the driest months, a lot of rain is still experienced. The average annual rainfall received in Leicester is 707 mm per year. This rain therefore produces large amounts of water which require a lot of ground surface to undergo seepage into the ground. It is therefore necessary to have as much green surface as possible which therefore means that the huge parking spaces put the city at risk of experiencing flash floods and storm runoffs.

• The clear aim of this research is to be able to analyze data and triangulations from satellites as well as other publications in order to determine the likely outcome and effects of the increase in concrete and paved surfaces such as car parking spaces and walking pavements which have been constructed at the expense of green surfaces
• This research shall also help to clearly show the need for more green surfaces in Leicester as well as other urban areas especially in the fight against flash floods and storm runoffs

Flash floods are sudden local floods that mostly occur after heavy rain. The water flows mainly from high altitude areas towards low lying areas. Apart from heavy rains, flash floods can also be caused by meltwater from ice or snow. Storm runoff on the other hand is free flowing rainwater that flows on the earth surface. It occurs when rainwater falls on paved surfaces that do not allow water to seep in to the ground. These paved surfaces include roads, parking lots, pavements, driveways and rooftops. Storm water runoff is a major cause of stream impairment in towns and cities. Leicester is an area located in the United Kingdom, Leicester experiences heavy rains throughout the year. The average annual rainfall received in Leicester in 707 mm per year. The climate in Leicester can be classified as Cfb according to the Köppen-Geiger system of classifying climate zones. The fact that Leicester experiences heavy rains throughout the year means that there is a lot of ground water in the area throughout the year. Without enough ground cover for this water to seep through, there are high risks of flash floods and storm water runoff occurring every time it rains. However, the number of paved surfaces in Leicester keep on increasing and raising the surface area of paved surfaces as the surface area of ground cover reduces. This is directly increasing the chances of these natural disasters happening. Despite the mitigation measures put in place such as trenches and sewer systems, the huge amounts of water on the surface often strain the mitigation measures and the flash floods and storm water runoffs keep occurring. We can use satellite data and triangulation to estimate the effect of these developments as well as to predict what could happen if the trend continues. This includes collecting rainfall data as well as geographical data on the topology of the area. The satellite data and triangulation can also help us to estimate the impact the flash floods and storm water runoffs could have on the environment as well as to predict and estimate the probability of their occurrence. The different types of soils can also be determined using satellite data and triangulation. This will help to understand which areas allow the most amounts of water to seep through and which areas allow water to run on the ground surface as surface runoff and ends up causing flash floods and the storm water runoffs. We can also be able to determine the surface area of all paved surface and be able to calculate the ratio of paved surfaces to ground surfaces. This can be achieved through maps and other map services such as google maps which are all facilitated by satellite data and triangulation.  By implementing the mentioned research ideas and by using the appropriate research methods, we can be able to compare the research data obtained against data from publications and to be able to draw reasonable conclusions that can help us to determine the most probable impact that storm water runoffs can have on paved gardens and concrete surfaces especially in the area of Leicester

Impact of Paved Surfaces on Flash Floods and Storm Runoffs in Leicester, UK

To determine the impact of flash floods and the storm water runoffs that come with them, different methods of research shall be used to obtain information to be used to draw conclusions. Some of the information that will be required include:

1. Amount of rainfall and the rainfall distribution in the area
2. Topography of the area
3. Ground surface area and area of paved surfaces in Leicester
4. Soil and soil distribution in Leicester

Materials needed

1. Data from the meteorological office
2. Satellite data

Results

Below is meteorological data of the area of Leicester showing the rainfall amounts and other meteorological information as collected from climate-data.org (en.climate-data.org, n.d.)

Observations

From the above data, a few points can be noted about rainfall:

i) July is the month that receives the highest amount of rainfall, 69 mm while February is the month that receives the lowest amount of rainfall at 45 mm.

ii) That from the driest month to the wettest month, there is a rainfall difference of 24mm

iii) July is the least humid month with a relative humidity of 71.80% while December is the most humid month with a relative humidity of 86.94%

iv) January with 12 rainy days is the month with the highest number of rainy days while September has the least number of rainy days at 9.97 days

Data Analysis

The above data shows how much rainfall the area of Leicester receives in a year. The data is distributed monthly for better clarity and to give more useful details that can help a researcher to understand the rainfall distribution throughout the year

Figure 1: A graph showing the temperature and rainfall of Leicester

From the above data and graph, its clear that the area of Leicester experiences high amounts of rainfall throughout the year. This means that there is always huge amounts of water on the ground surface which transform into surface runoff. There is also high humidity with low temperatures hence loss of water through evaporation is low. This therefore means most of the rain water that falls on the ground surface is either lost through seepage or moves across the surface as surface runoff.

As most of the water collects on the paved surfaces, it accumulates and leads to formation of huge flash floods that come with very strong storm water runoffs. This huge amounts of water on the ground can lead to accidents, injuries and destruction of property. As the height of the floods keeps on rising, the more dangerous the floods and storm water runoffs become. The strong floods also lead to destruction of paved surfaces as they occur frequently and with huge magnitudes.

Leicester as an area has an altitude of 62 meters. Its topographical map is as shown below. The map is obtained from topographical-map.com (topographic-map.com, n.d.)

Figure 2: A map showing the topography of Leicester and its surrounding areas

From the map, it can be seen that Leicester is a lowland that lies at the foot of two hills.

• Crown hills
• Dane hills
• Mowmacre hills

Leicester has an altitude of 62 meters. It is also a gently sloping land.

Leicester as an area lies at the foot of three hills. It is a low altitude area which is fairly flat. Therefore, because of its location, Leicester receives a lot of surface runoff from the three hills. All the water that collects at the top of the hills and on their escarpments flows rapidly down the slope towards the area of Leicester. This increases the amount of ground water that turns in to surface runoff. It also means that most of the mitigation measures put in place to prevent flash floods are often strained and therefore Leicester is always at risk of getting flash floods due to the water from the hills

Research Ideas using Satellite Data and Triangulation

The slope of Leicester also does not help as much as it is gently sloping or fairly flat which means the speed of water on the surface significantly. This raises the levels of flooding as most of the water collects on the paved surfaces and remains stagnant for large periods of time

The effect of this is that most of the paved surfaces are destroyed by the huge amounts of water that hit the ground with force as they move downhill and then remain stagnant on the surface for long periods causing decay and destruction of the paved surfaces. Hence the paved surfaces in Leicester require frequent maintenance due to the frequent destruction caused by rainwater

There are different types of soils (ABOUT CLASSIFICATION OF SOILS BY CONE

PENETRATION TEST, 2019). The different types of soils are classified based on their particle sizes. Sandy soils have large particles and therefore allow a lot of water to seep through hence reducing the amount of surface runoff. Sandy soils have low water retention ability. Clay soils on the other hand have very fine particles hence the do not allow a lot of water to seep through but allow it to pass on the surface as surface runoff. Clay soils have very high water retention ability as compared to sandy soils.

The soils in Leicester are very deep while being poorly drained. The soils are formed from coarse sandy soil and loam soils. The soils have moderate permeability which means they allow moderate amounts of water to seep through. The surface runoff in Leicester is slow while the saturated hydraulic conductivity is high. Due to the high amounts of rainfall throughout the year and the slow speed of surface runoff, the water table of Leicester is mostly at the ground surface or near the ground surface for the better part of the year.

Leicester also experiences low average temperature throughout the year; hence the rate of evaporation is always low. With this kind of conditions, we can conclude that the soil is always soaked. This greatly affects the paved surfaces as the soil is not strong enough to carry their weight. The water in the soaked soil also destroys the paved surfaces through erosion, weathering and decay. This leads to frequent destruction of the paved surfaces as well as frequent maintenance

During the research, there are quite a number of issues related to ethics that can be encountered (Felt, 2012).

One such issue is plagiarism. Since we are using satellite data and data from triangulation, there is a high risk of plagiarism. This is countered by making sure every source has been well cited and included in the references.

A few risks can be encountered during this research. Such risks include physical harm e.g., muscle strains due to long working hours. This risk can be prevented by taking breaks during tasks to ensure the body is well rested

The researcher also faces a risk of misrepresentation especially since the data requires his validation. The researcher should ensure his/her conclusions are solely based on the data collected and that he/she eliminates all ambiguity

Reference list

ABOUT CLASSIFICATION OF SOILS BY CONE PENETRATION TEST. (2019). ?????????? ????????, XIV(4). doi:10.25296/1993-5056-2019-14-4-6-23.

en.climate-data.org. (n.d.). Leicester climate: Average Temperature, weather by month, Leicester weather averages - Climate-Data.org. [online] Available at: https://en.climate-data.org/europe/united-kingdom/england/leicester-17/.

Felt, L. (2012). Book Review: Ethics Protocols and Research Ethics Committees: Ethics Protocols and Research Ethics Committees: Successfully Obtaining Approval for Your Academic Research. Journal of Empirical Research on Human Research Ethics, 7(3), pp.91–92. doi:10.1525/jer.2012.7.3.91.

Mack, T. and Bedford, C. (2021). Leicester floods after torrential rain hits Leicestershire. [online] LeicestershireLive. Available at: https://www.leicestermercury.co.uk/news/leicester-news/live-updates-flooding-torrential-rain-5722834.

Met Office (2019). UK regional climates. [online] Met Office. Available at: https://www.metoffice.gov.uk/research/climate/maps-and-data/regional-climates/index.

topographic-map.com. (n.d.). Leicester topographic map, elevation, relief. [online] Available at: https://en-gb.topographic-map.com/maps/19/Leicester/.

Wikipedia Contributors (2019). Köppen climate classification. [online] Wikipedia. Available at: https://en.wikipedia.org/wiki/K%C3%B6ppen_climate_classification.