Floods Physical Processes and Environmental Impact on Human
CHAPTER ONE
Objectives of the Study
The aim of this study is to investigate the physical processes of floods and environmental impact on human. The specific objectives of this study are to:-
- Identify the causes of flooding prevalent on transportation land use.
- Examine the environmental problems of flooding on transportation land use.
- Recommend possible control measures on the problems of flooding on transportation land use.
CHAPTER TWO
LITERATURE REVIEW
General consequences of a flood
Floods can be classified in four types ( Peterson, 2001) based on their characteristics of the flood event:
- flash floods of a few hours duration;
- single event flood of long duration;
- multiple-event floods; and seasonal floods.
Similarly, based on the source type, floods my be classified mainly as:
- Rainfall flood,
- Snowmelt flood,
- Sea surge or tidal flooding,
- Dam brake flood.
Broadly floods can be classified as River floods and Coastal & Estuarine floods:
- River floods: caused by rainfall, snow and ice-melt, ice jams, landslides
- Coastal and Estuarine floods: caused by coastal storm surges, tides, earthquakes.
The common to all of these floods is the economic, social and environmental effect.
The phenomenon of flooding is a natural occurrence, which may bring both adverse and beneficial environmental changes. Flood is an event that generates loss of lives and properties. If such an event is not so much of life threatening one, it will still generate collective stress and serious disruption of community live even after a long time later. Flash floods generate sudden and massive impacts, whereas the gradually occurring floods may allow longer period of time for evacuation and protection of properties.
Flood impacts are evaluated on the extent of inundation in the floodplains (maximum depth and duration of flooding); velocity of flow, and rate of rise of flood levels.
Basic environmental impacts of flood are on morphological changes along the river course. The shape of the river valley is often determined more by the catastrophic event than by the gradual but insidious process of erosion and deposition that takes place at flows which are confined within banks.
Morphological process is a primary factor in forming the natural habitat for flora and fauna (Gardiner,1992). Consideration of environmental impacts of the flood regime should also include the direct as well as indirect impacts including those associated with human activities.
CHAPTER THREE
RESEARCH METHODOLOGY
Introduction
This chapter covers the description and discussion on the various techniques and procedures used in the study to collect and analyze the data as it is deemed appropriate
Research Design
For this study, the survey research design was adopted. The choice of the design was informed by the objectives of the study as outlined in chapter one. This research design provides a quickly efficient and accurate means of assessing information about a population of interest. It intends to study floods physical processes and environmental impact on human. The study will be conducted in Edo state.
Population of the Study
The population for this study were residents in Oredo local government, Edo state, Nigeria. A total of 134 respondents were selected from the population figure out of which the sample size was determined. The reason for choosing Edo state is because of its proximity to the researcher.
CHAPTER FOUR
DATA ANALYSIS AND INTERPRETATION
Introduction
This chapter deals with the presentation and analysis of the result obtained from questionnaires. The data gathered were presented according to the order in which they were arranged in the research questions and simple percentage were used to analyze the demographic information of the respondents while the chi square test was adopted to test the research hypothesis.
Table 1 above shows the gender distribution of the respondents used for this study. Out of the total number of 100 respondents, 65respondents which represent 65.0percent of the population are male. 35 which represent 35.0 percent of the population are female.
CHAPTER FIVE
CONCLUSIONS AND RECOMMENDED RESEARCH
Extreme flooding events are reset mechanisms for nature, civilization, and political policy. Driven by an instinct to master his surroundings and prevent the periodic regressions created by floods, man has warped natural systems by greatly altering hydrologic regimes. Some forms of structural flood control are now known to increase the frequency of extreme high water. Nonstructural flood control presents an opportunity to reduce the frequency and magnitude of extreme events and improve aquatic environments. Hey and Philippi (1995) estimate that 13.3 million acres of wetlands would provide the Mississippi River basin with non-structural flood control capable of handling the once in 100-year event. Missouri was one of nine states that sustained significant damages in the Great Flood of 1993 (Meyers and White, 1993). In Missouri alone, 227,585-acres of cropped floodplain lands were covered by over nine inches of sand and are unlikely to ever return to agricultural production (U.S. Congress, 1994). Assuming that only five of the other eight states sustained similar agricultural losses to those in Missouri, ten percent of the area required by Hey and Philippi’s plan is now dormant under a blanket of sand. At the very least, a large-scale study area of the now nonarable land should be used as an experimental site for floodplain restoration and wetland construction. Recommended research areas pertaining to this manuscript are Continued study of managed floods as tools for reestablishing natural dynamics. The Glen Canyon dam flood expanded the scope of controlled floods to include the initiation of geomorphic processes important in maintaining aquatic habitat for native species. This was an invaluable contribution. In large low-gradient systems, the biotic production boost from flooding in wetlands and floodplains should be quantified for a range of return frequencies. This would refine controlled flooding as a tool for biologists and environmental managers. Identify system weaknesses and operational shortcomings based on historic floods and develop conceptual improvements, including the integration of non-structural alternatives, in anticipation of major floods instead of in response to them. This may be accomplished by approaching problems holistically. By considering the entire system, operational plans should integrate existing and proposed structural and non-structural flood control measures to compose comprehensive flood management strategies. If severe flooding remains the major impetus for policy change, a plan in hand will allow full utilization of the post-flood window of opportunity created by heightened social awareness and disabled structural controls. • Continued study of the quantitative environmental aspects of severe flooding. A new branch of study should include ecological and biological modeling. Currently, there are computer models available for modeling aquatic habitat (Bovee, (ed.), 1996) and fish populations in temperate river systems (Cheslak and Jacobson, 1990; Bartholow et al., 1993). As these models rely on hydraulic calibration data that are best gathered at low flows, use of these evaluative natural system models is suspect at the high flow levels critical to population dynamics. Even though geomorphic changes during extreme events upset characteristics of the physical stream habitat, the validity of model responses to extreme flows should be tested. The game of hydrologic roulette can be weighted in our favor by incorporating nonstructural flood control measures into flood management. This includes the restoration of wetland areas and reconnection of key floodplain areas. By applying new science to old lessons we can break the cycle of policy change in response to destruction.
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