Mobility especially in the form of transportations requires an increasing share of land, both within cities and in rural areas. Effective utilization of land encourages urban activities, and roads and other transportation facilities are maintained so as to allow for new transportation-related activity. Creating new roads or expanding existing ones increases the attractiveness of the land they pass through, promoting new urban facilities. When cities are growing slowly, it is easy for land utilization and traffic planning to match pace. In times of rapid economic growth, however, demand for land use accelerates and development of transportation facilities may be unable to keep up.
Many cities experiencing a high degree of economic growth will therefore experience heavy congestion and other transportation problems. Landuse planning is necessary to assure sound land transportation system (NRC (2008). Severe weather such as hurricanes, thunderstorm, storm surge, flooding, lightning, and rise in sea level has adverse impacts on the transport system. Flood profoundly affects transportation. Landuse. Flooding increases the cost of designing, operation, construction, maintenance, rehabilitation, and repairmen costs of transportation landuse.
Another impact of flooding is that it causes delay, disruption or closure of transport network operations ((DTLR) (2002)
The road transportation system has many economic importance. At present, roads are carrying about 70% of the goods, and the trend is rising. However, flood adversely affects road transport system in many ways. Frequent occurrence of flood causes roads to create potholes a short period of time after their construction while the exist¬ing one will deepen rapidly and easily.
Flooding may shorten the service life of black-top road surfaces. In this manner, poor roads resulting from substantial flood-induced potholes results in car crashes and causes vehicular congested driving conditions which prompt more fuel utilization notwithstanding considerable time wasted. Benin city suffered from flooding effect on the transportation landuse resulting feeder streets being destroyed, bridges collapsed and culverts were destroyed due to heavy flooding (Dipanjan, 2014). Temperature in the earth surface will increase by 2˚C in 2050. Budyko, (2016) studied the consequences of flooding on the road in three southern African countries (Malawi, Mozambique, and Zambia). The study concluded that these three countries are facing a potential $596 million price tag for maintaining and repairing roads damaged directly related to flooding Verkerk, Kuemmerle, & Schrammeijer (2018) researched the effect of flooding in five European countries (Italy, German, Belgium, the Netherlands and Spain) road and rail transport infrastructures.
This research concluded that flooding increases maintenance & repair costs for the road by 30% up to 50% or 10 billion €/year. Gabriel (2017) also studied the economic impact of flooding on land-based transportation in Australia. He found that the total the costs of the impact on the road transport sector were about € 47 million per year. When analyzed across cost categories, the lion’s share of costs is owing to harms to road infrastructure which is € 39 million every year (82% of the aggregate). The second largest cost component was vehicles damage (€ 5 million per pear) which accounts for 10% of the total cost. Francisco (2012) found that road cracking and potholes in five European countries namely Italy, Spain, Belgium, German and the Netherlands is due to the effects of flooding. According to this study, the maintenance cost for pothole and cracking road due to flooding was 500 to 170 million €/year. EPA (2010) also indicated that the Accra floods in 2009 practically rolled off the asphalt on the Kaneshie Highway while flooding in Swedru thoroughly washed away parts of the main road in the town. According to Djei-Mantey, 2014), due to this flood about $44.2 million was incurred in the greater Accra region of Ghana. Madan (2009) studied the impact of the flood in Bangladesh and concluded that the damage done to the road transport landuse by 2007 floods was $363 million. Sea level rise (SLR) is a important in understanding flood effect on transportation landuse in areas with coastal areas (Nicholls and Cazenave, 2010). Sea level rise can flood unpaved and graveled roads adjacent to the seashore. If sea level rises by 1m in Europe will costs € 18.5 billion. In Benin flooding is more intense during raining season. Heavy rains may result in flooding, which could disrupt traffic, delay construction activities, and weaken or wash out the soil and culverts that support roads, tunnels, and bridges. Flooding causes pavement to soften thereby creating rutting and potholes, particularly in high-traffic areas. Flooding can also generate stress on bridge joints (Odemerho, 2008). Floods limit construction activities, particularly in areas with high humidity. As a result of these problems it is very difficult and costly to build and maintain roads and highways. Exposure to flooding shortens the life expectancy of highways and roads. The stress of flood may cause damage, requiring more frequent maintenance, repairs, and rebuilding. Road transportation system in Benin city is particularly sensitive to more frequent flooding from the blockage of water channels and overflow of River banks. Flooding could occur more frequently if the ground cannot absorb water. Landslides and wash-outs could also occur more frequently, as saturated soils are exposed to more rainwater.
Flooding affects the operability of railway transportation system. Railway tracks are usually designed to withstand a sensible flood and temperature range (Chapman et al., 2005). Flooding may cause material wear, including clasped rails. Duinmeijer and Bouwknegt (2004) studied the adverse effect of flooding on rail transportation system failures in Ghana in the year 2003. The findings revealed that roughly 5 to 10% of all failures were flood-related. A large portion of the flood-related failures are caused by excess rainfall. As indicated by Daniel (2017), the present normal yearly flood-induced costs in the rail transportation in Australia were €18million. With regard to the cause of damage, around 95% of all rail way damages were activated by surge and rain. In Bening city flooding leave debris on railways, disrupting rail travel. Like roadways, railways and subways are subject to floods from sea level rise. This is particularly true in underground pathways and tunnels, which are often already below sea level. Damages from flooding may require rail lines and subway infrastructure to be rebuilt. More frequent and severe heat waves may require track repairs or speed restrictions to avoid derailments.
Flood mitigation involves the management and control of flood water movement, such as redirecting flood run-off through the use of floodwalls and flood gates, rather than trying to prevent floods altogether. Mitigation could be structural or non-structural (Ainullotfi, Ibrahim, & Masron, 2014). Structural Mitigation is the physical changes or act of protection from disasters or hazards. For example, structural mitigation could be reinforcing an area to make it more wind proof, flood proof or earthquake proof. In addition, other structural mitigation examples could be things like creating a sandbag barrier around the area where flood might occur. In general structural mitigation is the direct actions that people take, build, or move in order to better preserve their life and or property. Non-structural mitigation in emergency management involves what people can do on a personal level that is not structurally or physically evident as a protective defense such as a surge wall or a storm shelter. Non- structural mitigation in general involve things such as having flood insurance. In addition another example could be creating an emergency plan. Any mental preparedness, training, insurance, discussion, and planning could be considered items of non-structural mitigation Hazards cannot be prevented from occurring especially natural hazards such as flooding but the vulnerability associated with flood disaster can be mitigated by one aspect of disaster management: preparedness. Preparedness action is closely related to how individuals perceive and act on risk information (Ologunorisa, 2009). Preparedness measures have the big advantage of being able to address root causes and dynamic pressures instead of symptoms in a system, which is more stable than after a disaster (Enenkel, 2010). It is also true that no two flood events and disasters are exactly the same, but the many aspects of the full life cycle of disaster management can help mitigate a flood disaster. Flood preparedness plan (FPP) is about putting in place a set of appropriate arrangements in advance for an effective response to floods. This is an important phase of flood disaster management which is almost being neglected in developing countries such as Nigeria. There is a tendency to rely more on what the government can do while neglecting self-help options. Thus disaster risk reduction measures that reduce the vulnerability of flood disasters are advocated for in view of the fact that the cost implication of recovery and rehabilitation measures are enormous compared to preventive strategies such as preparedness actions. Herath (2003) used five research-proven criteria : (1) Effective and efficient waste management board (2) Having a non-moribund Ministry of Environment (3) Embracing effective horticulture and greening of the environment (4) Effective and efficient transport management agency (5) Having a central and well-managed motor park Others are: – Desilting of drainages – Drainage networks – Creation of canals – Sand bags – Proper landuse planning – Flood insurance
This study anchored on Disaster Risk Management (DRM) approach promoted by the United Nations through the International Agency for Disaster Reduction – ISDR. One of the main aspects in this approach is that disasters are not seen as events of nature by itself but the product of intricate relationships linking the natural and organizational structure of a society (UN-ISDR, 2005). Given the strength of the physical forces involved and the human socioeconomic interdependence on climate and the environment, it is unlikely that adverse impacts from climate (e.g. flooding) events can ever be totally eliminated (UNDP, 2002). Natural disasters such as flood are inevitable, no matter the amount of the study carried out and the precautions taken in this direction, the natural disasters cannot be prevented, but the efforts can always be put and be successful in reducing the impact of them on people and communities. So identifying and studying the flood disaster and taking appropriate actions to control or manage them are government and the community. 2.10 Empirical Review Inu Pradhan and Jiba Raj associated urban flooding to the impacts of urbanization and climate change in Kathmandu]. Their research explored the relationship between the increasing urban runoff and flooding due to increased imperviousness and extreme rainfall events due to climate change in the study area. The findings of the research show that future climate change conditions with present urbanization will increase pluvial flooding. Schneider et al. reported on climate change impacts on urban flooding. In their paper, they estimated changes in the potential damage of flood events caused by increases of CO2 concentration in the atmosphere.
This they presented in two parts: 1. The modeling of flood frequency and magnitude under global warming and associated rainfall intensities and 2. The use of greenhouse flood data to assess changes in the vulnerability of flood-prone urban areas. Stephen (2011) observes that it is evident from research that residents contribute greatly to flood problems of their area and their act jeopardizes the environment which attracts many people for economic, social and recreational facilities. Aderogba carried out a study to examine the peculiarities of the flood in Nigerian urban areas and its challenges. The research involves a study on the incidence of the flood in twenty-five towns in Nigeria using data on flood depth, width, frequency, and duration obtained between 1981 and 2001. He observed flood and administered the questionnaire to obtain relevant information on the incident of flood and concluded that human factors are the cause of flooding in Nigeria. He asserts that torrential rain is not the main cause of flood but the living habits of the residents and lack of proper planning of the physical environment. Ogundele et al. examined the environmental consequences of an urban flood on the growth and development of Ado-Ekiti, Nigeria by administering the questionnaire on respondents in the study area. Results from this study revealed that high intensity of rainfall, surface roughness, dumping of refuse on drainage channels, poor construction of drainage channels and poor town planning practices are the main causes of urban flood problems in the study area. The result is in line with Adeloye and Rustum observed that the basic cause of the urban flooding was man’s modification of the basic drainage network and channels characteristics during the process of settlement development on the floodplain. He noted that natural surfaces were replaced by more impermeable roads and concrete which have very low infiltration capacity. Olajuyigbe et al. observed that flood was the most of serious physical development problem in most cities in Nigeria. The research methodology involved the use of remote sensing and questionnaire administration on one hundred and sixty-six households and members of the Lagos State Planning Authority. Three neighborhoods in the settlement that annually experience flood were used for the analysis. Data on population, the extent of areas affected by the flood, households, and buildings were collected and analyzed. The result showed that perennial flooding problem in Mile 12 was as a result of blockage of drainage channels by refuse and other wastes, consistent high rainfall, and water releases from the Oyan dam. Olajuyigbe et al. recommended the provision of sufficient set back from the river floodplain, construction of roads with good drainage, channelization, and building of more dams to avoid excess loading of the existing dam. This research was in agreement with the conclusion of Nwafor who listed surges in water level, poor planning and development control, inappropriate drainage capacity and poor waste management as causes of urban flooding. Olorunfemi made a comparative assessment of the impacts and response to flood risk among the urban poor living in the highly vulnerable informal settlements in the Cape Town, South Africa and those of Asa in Ilorin Nigeria. The paper explored the vulnerabilities of the two areas and suggested ways of tackling them. He employed an integrated hazard and vulnerability paradigm to examine the cause of vulnerability and impact of flood in the communities studied. Ologunorisa investigated flood risk mitigation strategies in the Niger Delta of Nigeria by examining the flood control measures in place and observed that the structural method of flood control tends to give a false sense of security to floodplain dwellers thereby encouraging investments in flood prone areas. He observed that non-structural methods, (public relief funds, flood insurance, flood forecasting and warning schemes), though found frequently used in rural areas were basically behavioral adjustments to flooding. Ologunorisa observed that no attempt was made by the people at risk to adjust to the hazard except to replace lost or damaged goods following a flood event. He X-rayed the short comings inherent in the flood alleviation measures and recommended the establishment of coastal zone management authority, land use zoning and proper legislation to guide the use of land.
The study examines environmental impact of flooding on transportation land use in Benin city, Edo State. The present chapter reviewed several literatures in relation to the topic of the study. An attempt was made to analyze the causes of flood on transportation landuse. Flood prone areas in Benin city were identified. The chapter investigated the major impact of flooding in transportation land uses based on the two major mode of land transportation (road and railway). Mitigation strategies for control of floods were reviewed. Disaster management approach was identified as suitable for the study. Previous studies reviewed were based on the effect of flood hazard on urban cities, the present study has come to cover the gap in literature by choosing the topic of the study.