Effects of Urban Construction on Vegetation and Rainfall Runoff
CHAPTER ONE
Objectives of the Study
The major objective of the study is the effect of Urban construction on vegetation and rainfall. This is to be achieved through the following specific objectives;
(i) Observations from monitoring of two adjacent catchments are utilized to characterize rainfall runoff response from different types of urban construction,
(ii) The temporal and spatial change in urbanization is mapped for a particular period and
(iii) Finally, a semi distributed hydrological model is calibrated and validated against observed rainfall runoff and subsequently used to back cast and investigate the effects of urbanization process on vegetation and rainfall runoff.
CHAPTER TWO
REVIEW OF RELATED LITERATURE
Runoff
Surface runoff occurs when rainfall exceeds a soil’s maximum saturation level and all surface depressional storage is filled to capacity. The rate of runoff flow depends on the ratio of rain intensity to the infiltration rate. If the infiltration rate is relatively low, such as when a soil is crusted or compacted, and the intensity is high, then the runoff rate will also be high. (National Soil Erosion Research Laboratory). From AMS glossary, surface runoff is the water that reaches streams (ranging from the large permanent streams to the tiny rills and rivulets that carry water only during rains) by travelling over the surface of the soil. Thus, surface runoff takes place only over the relatively short distance to the nearest minor channel. According to the Department of Atmospheric Science, Runoff is the movement of land water to the oceans, chiefly in the form of rivers, lakes, and streams. Runoff consists of precipitation that neither evaporates, transpires nor penetrates the surface to become groundwater. Even the smallest streams are connected to larger rivers that carry billions of gallons of water into oceans worldwide. Excess runoff can lead to flooding, which occurs when there is too much precipitation. Science Daily defines surface runoff as the water, from rain, snowmelt, or other sources, that flows over the land surface, and is a major component of the water cycle Wiki encyclopedia defines surface runoff as the water flow that occurs when soil is infiltrated to full capacity and excess water from rain, melt water, or other sources flows over the land. This is a major component of the water cycle.( Robert E. Horton 1933 and Robert E. Horton 2004) Runoff that occurs on surfaces before reaching a channel is also called a nonpoint source. If a nonpoint source contains man-made contaminants, the runoff is called nonpoint source pollution. A land area which produces runoff that drains to a common point is called a watershed. When runoff flows along the ground, it can pick up soil contaminants including, but not limited to petroleum, pesticides, or fertilizers that become discharge or nonpoint source pollution.( L. Davis Mackenzie and Susan J. Masten )
If the amount of water falling on the ground is greater than the infiltration rate of the surface, runoff or overland flow will occur. Runoff specifically refers to the water leaving an area of drainage and flowing across the land surface to points of lower elevation. It is not the water flowing beneath the surface of the ground.
CHAPTER THREE
RESEARCH METHODOLOGY
Research design
The researcher used descriptive research survey design in building up this project work the choice of this research design was considered appropriate because of its advantages of identifying attributes of a large population from a group of individuals. The design was suitable for the study as the study sought to examine effects of urban construction on vegetation and rainfall runoff
Sources of data collection
Data were collected from two main sources namely:
- Primary source and
- Secondary source
Primary source:
These are materials of statistical investigation which were collected by the research for a particular purpose. They can be obtained through a survey, observation questionnaire or as experiment; the researcher has adopted the questionnaire method for this study.
Secondary source:
These are data from textbook Journal handset etc. they arise as byproducts of the same other purposes. Example administration, various other unpublished works and write ups were also used.
Population of the study
Population of a study is a group of persons or aggregate items, things the researcher is interested in gathering information relevant to effects of urban construction on vegetation and rainfall runoff. Two hundred (200) residents in Lokoja were selected randomly by the researcher as the population of the study.
CHAPTER FOUR
ANALYSIS AND PRESENTATION OF DATA
One hundred and sixty (160) questionnaires were distributed and one hundred and forty (133) were returned. This figure was the sample size. Out of the one hundred and thirty-three, only one hundred and twenty (120) were properly responded to. As a result, the researcher used one hundred and twenty for this study when more than 50% of the respondents agree to the questions, the answer is taken as valid for the purpose of this study. In analyzing the data, the approach that will be adopted is to find out the percentage and positive and negative answers to the question posed.
CHAPTER FIVE
SUMMARY, CONCLUSION AND RECOMMENDATION
Introduction
It is important to ascertain that the objective of this study was to ascertain effects of urban construction on vegetation and rainfall runoff
In the preceding chapter, the relevant data collected for this study were presented, critically analyzed and appropriate interpretation given. In this chapter, certain recommendations made which in the opinion of the researcher will be of benefits in addressing the challenges of effects of urban construction on vegetation and rainfall runoff
Summary
This study was on effects of urban construction on vegetation and rainfall runoff. Three objectives were raised which included: Observations from monitoring of two adjacent catchments are utilized to characterize rainfall runoff response from different types of urban construction, the temporal and spatial change in urbanization is mapped for a particular period and Finally, a semi distributed hydrological model is calibrated and validated against observed rainfall runoff and subsequently used to back cast and investigate the effects of urbanization process on vegetation and rainfall runoff. The researcher used questionnaires as the instrument for the data collection. Descriptive Survey research design was adopted for this study. A total of 133 respondents made up of students, civil servant, business owners and youths were used for the study. The data collected were presented in tables and analyzed using simple percentages and frequencies
Conclusion
Runoff is the component of the hydrologic cycle through which water is returned to the ocean by overland flow. The term runoff is considered synonymous with stream flow and comprises surface runoff resulting from precipitation and that portion of the stream flow that is contributed by groundwater flow entering the stream channel. In this term paper, the effects and impacts of runoff is greatly expatiated but I will conclude from the perspective of an engineer that a large segment of engineering practice deals with the control, conservation and utilization of that water which the hydrologist classifies as Runoff. The recent upward trend in the number and size of hydraulic projects reveals a creditable public determination to make full use of this resource. The present day practicing engineer, therefore, requires an understanding not only of the laws, principles, magnitudes and fluctuations in stream flow but also of the laws and principles governing surface and subsurface water before it reaches defined channels. Hydraulic power generation, irrigation, flood control and municipal and industrial water works are only a few of the manifold applications of engineering to the development of a public resource.
Recommendation
The impact of underground runoff is complex. Here, the land-use change has been only studied from the perspective of underlying surface permeability. Nonetheless, we are aware of other land-use change indexes that do not consider the use of permeable pavements, which may lead to the impermeable facilities being classified into the same underlying surface. Therefore, the analysis index of the underlying surface could be further improved, which would lead to more accurate statistical results.
References
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- Dingman S. L. (1994) Physical Hydrology, 575 pp. New York – Oxford – Singapure – Sydney: Maxwell Macmillan International. [A useful attempt to introduce hydrology as a systematized science about the Earth]
- Gupta R. S. (1989). Hydrology and Hydraulic Systems, 739 pp. Englewood Cliffs, NJ, USA: Prentice Hall. [Description of methods and procedures of physical and stochastic hydrology in application both to natural objects and to those created by humans
- Kundzewicz Z. W., Gottschalk L. and Webb B (Eds.) (1987). Hydrology 2000. The Report of Hydrology 2000 Working Group, established 1983 and disbanded August 1987, 100 pp. IAHS Publication no 171. [It presents the views of some hydrologists on the hydrology state at the end of the 20th century]
- Liebscher H-J. (Ed.) (1990). Lehrbuch der Hydrologie, Band 1 Allgemeine Hydrologie, 673 pp. Berlin – Stuttgart, Deutschland: Gebrüder Borntraeger. [It broadly presents traditional ideas of hydrology and runoff]
- Lvovich M. I. (1986). Water and Life [in Russian], 256 pp. Moscow, USSR: Mysl. [It presents the views of hydrologist-geographer on the water balance and water resources in conditions of anthropogenic impact]
- Manning J. C. (1992). Applied Principles of Hydrology, 294 pp, New York – Oxford -Singapore – Sydney: Maxwell Macmillan International. [Description of the elements of hydrological cycle with consideration of the examples of solution of a number of practical tasks]