Effects of Anthropogenic Activities on Nworie and Otamiri River

A Case Study


Bachelor Thesis, 2019
66 Pages

Free online reading

TABLE OF CONTENTS

Title page

Certification

Dedication

Acknowledgement

Abstract

Table of Contents

List of Tables

List of Figures

CHAPTER ONE

1.0 INTRODUCTION
1.1 BACKGROUND OF STUDY
1.2 STATEMENT OF PROBLEM
1.3 AIM AND OBJECTIVE OF THE STUDY
1.4 SIGNIFICANCE OF STUDY
1.5 SCOPE OF STUDY

CHAPTER TWO

2.0 INTRODUCTION
2.1 STREAM MORPHOLOGY
2.2 CHANNEL PROCESSESS
2.2.0 EROSION
2.2.1 TRANSPORTION
2.2.2 DEPOSITION
2.3 EFFECT OF ANTHROPOGENIC ACTIVITIES ON CHANNEL MORPHOLOGY
2.3.1 OBSTRUCTION OF NATURAL FLOW
2.3.2 WATER POLLUTION
2.3.3 DEFORESTATION AND LOSS OF NATURAL HABITAT

CHAPTER THREE

3.0 INTRODUCTION
3.1 STUDY AREA
3.2 LAND USE CHANGE
3.2.1 DATA COLLECTION
3.2.2 RESEARCH DESIGN (DATA ANALYSIS)
3.3 FIELD SURVEY
3.3.1 SELF-ADMINISTERED QUESTIONNAIRE
3.3.2 PARTICIPANT OBSERVATION
3.3.3 SAMPLING FRAME AND TECHNIQUE
3.3.4 TOOLS OF DATA ANALYSIS (SOFTWARE USED)

CHAPTER FOUR

4.0 INTRODUCTION
4.1. IMAGE CLASSIFICATION ACCURACY 4.1.1
LULC CLASSIFICATION MAPS AND OUTPUT
4.1.2 LAND USE LAND COVER DISTRIBUTION.
4.1.3 RESULT OF RESPONDENTS
4.1.4 RESULTS OF FIELD MEASUREMENT
4.2 DISCUSSION
4.2.1 LAND USE CLASSES AND CHANGE IN LAND USE LAND COVER
4.2.2 EFFECTS OF LAND USE LAND COVER CLASSES ON THE HYDROLOGICAL REGIME

CHAPTER 5

5.0 INTRODUCTION
5.1 SUMMARY
5.2 CONCLUSION REFERENCE

Appendices

LIST OF FIGURES

Figure 2.1: The Longitudinal Profile of a typical river

Figure 2.2: an image showing knick point

Figure 3.1: A map showing the study area

Figure 4.1: 1986LULC Classification of the Study Area

Figure 4.2: 2000 LULC Classification of the Study Area

Figure 4.3: 2016LULC Classification of the Study Area

Figure 4.4: LULC Change Distribution (1986 - 2000 – 2016)

Figure 4.5: Activities of the dominant in the area

Figure 4.6: Ratio of land owners surveyed

Figure 4.7: observed land uses by the owners41

Figure 4.8: Changes in the study area42

Figure 4.9: Respondent’s observation on changes in river channels44

Figure 4.10: A morphological map of the Nworie /Otamiri River 45

Figure 4.11: an image showing an eroding part of the Otamiri River49

LIST OF TABLES

Table 3.1: GPS coordinates of some locations along Nworie River26

Table 3.2: GPS coordinates of some locations along Otamiri River26

Table 3.3: showing the source of Satellite Images 27

Table 3.4: Land use land cover classification scheme28

Table 4.1: summary of overall classification accuracy and kappa coefficient.32

Table 4.2: Land Use Land Cover Distribution (1986, 2000 and 2016)36

Table 4.3: LULC Change between 1986, 2000 & 201638

CERTIFICATION

This is to certify that this project entitled Effects of Anthropogenic Activities: A Case Study of Otamiri AND Nworie River, Imo State Nigeria was carried out by Okorofor Johnpaul, 20121824514 of the Department of Environmental Technology, School of Environmental Sciences, Federal University of Technology, Owerri

Dr. Martin Iwuji Date (Supervisor)

Date

Prof P.N Okeke Date

Date

(Head of Department)

Date

(External Examiner)

Date

DEDICATION

This project is dedicated to God Almighty, My Family and friends for their contribution to my education.

ACKNOWLEDGMENT

I would like to express my heartfelt gratitude to my supervisor Dr Martin Iwuji of environmental technology department for allowing me to complete this work under his elegant supervision and guidance. His encouragement throughout these times of difficulties was something that cannot be expressed with mere words. I am deeply indebted to him My thanks also to my head of department prof P.N Okeke and my course adviser Dr Amangabara for their hearty cooperation during my research work and other lecturers Dr Ihejirika, Dr Ogbuagu, Dr Akinbare, Mrs Ogechi, Dr Vela, Dr J.D Njoku and Dr P.C Njoku who all contributed a lot in moulding me into a considerable academic shape.

I immensely appreciate the effort of my family Mr and Mrs Okoroafor and My siblings Master Peter and Master Patrick, who remembered me in their prayers. To my friends Promise Christopher, Eesbay Ruben and Jacob Okoro, you have been such a wonderful companion.

Finally, everything in this nature is time bound, so thanks to “God Almighty” for successful completion of the work in time.

OWERRI

OKOROAFOR J

2017

ABSTRACT

This research work seeks to study the effects of anthropogenic activities on the

Nworie and Otamiri river morphology in Imo State Nigeria. Using land use/ land cover change analysis to evaluate the degree of the effect anthropogenic activities have on the morphology of the river and the major human divers causing this geomorphic change to the catchment.

GIS was a major tool for the analysis of aerial photographs gotten from Landsat

5, 7 and 8 satellites. The images from years 1986, 2000 and 2016 were all analysed and land use/ land cover were classified into 5 classes namely water body, light forest, thick forest, bare surface and built up area. Questionnaire was used to retrieve data during the field work. 100 respondent answers were analysed to gain information about observed human activities around the study area. The combined results from the analysed images and questionnaires formed the basis of the research findings.

The findings of the research suggest morphological change to the Nworie and Otamiri River. This is primarily as a result of human activities such as farming, dumping of refuse, building of structures like roads, sand mining and dredging. This activities cause the widening and narrowing of the River banks.

In order to protect the river morphology, strict government policies that protect environmental landforms from degradation must be implemented and stringent penalties should be awarded to defaulters.

CHAPTER ONE

INTRODUCTION

1.0 BACKGROUND OF STUDY

It is quite obvious that human actions leave a mark on the environment, stating since the 18th century, and now they have increased in influence and actively affect the functioning of earth systems (Negrel, Merly, Gourcy & Sedan. 2014). These human imprints are often referred to as anthropogenic activities which may be point source (having direct impact) or non-point source (having an indirect impact). Lal (2006) classifies anthropogenic activities as either agricultural activities, industrial activities or urbanization. Isik, Dogan, Kalin, Sasal & Agiralioglu (2008), further lists these human activities such as industrial and agricultural needs, sand mining, diversion of bed material or flow, water withdrawal for urban use, change of land use and construction of dams, levee and bridges.

There is an observed connection between our actions as human beings and geomorphological changes onplanet earth. The term Anthropocene, introduced some years back (Crutzen, 2002), has only recently become widely, but informally, used in the global change research community (Steffen, Crutzen & Mcneil 2007). The Anthropocene corresponds to the current epoch in which humans and our societies have become a global geophysical force. The development of the Anthropocene started around the 18th century with the advent of industrialisation as analyses of air trapped in ice caps in the Polar Regions suggested an increase in the carbon dioxide and methane concentrations in the environment. Since its introduction, Anthropocene was used in many studies of the environment such as sediment investigations, land cover change or rather more political reflections (Negrel, 2014). It is for this reason Urban & Rhoads (2003) pointed out that comprehending the connection between the effects of geomorphological processes and human activities in shaping the form of fluvial systems not only informs public deliberation about environmental management of streams, but also contributes to peripheral knowledge about the role of humans in shaping stream morphology.

Channel morphology, is a branch of geomorphology in which the focus is on the area influenced by large bodies of water, including seas and oceans, and large lakes (McCann, 2013). Fashea & Faniran (2015) however stated thatriver morphology depicts the form of a river along its length and across its width and consequently its shape. River morphology is explained by channel patterns and channel forms, and is influenced by such factors as water surface slope, depth and width of the channel, discharge, water velocity, amount and size of the transported material and river bed materials. Although McCann (2013) further adds that in the study of rivers, channel geometry changes with time and there are five main physical factors described that affect the channel morphology: bank and bar stability; sediment size distribution; sediment supply; flow variability; and downstream slope, width and height. It is for such reasons that river morphology has been a subject of great challenge to scientists and engineers who recognized that any effort with regard to river engineering must be based on a proper understanding of the morphological features involved and the responses to the imposed changes (Chang, 2008).

1.1 STATEMENT OF PROBLEM.

For a while now, stream morphology researches has been carried out by scientists in a wide variety of disciplines, yet our understanding of channel morphology, features and the factors influencing them is still incomplete. Most geomorphological investigations involving channel morphometry are concerned with the definition, measurement and analysis of quantitative indices describing the cross section, the bed form and longitudinal profile as well as the plan geometry of rivers (Fashea & Faniran, 2015).This is because of differences in the land use setting where climate, physiography and geology could influence how geomorphic conditions react to urban development as stated by Paul & Meyer (2001).

The individual characteristics of each river should be studied so that the responses of the river due to any encroachment in the flood plain and more in the case of future man-made structures may be anticipated and preventive measures as considered necessary may be planned beforehand (Maurya, 2013). The morphological characteristics of the Nworie and Otamiri River has changed over time, this is majorly because of the activities such as dredging, sand mining, agriculture and building near the bank. These activities have caused the water level to recede that is places water once covered is now bare land.These morphological changes have increased the tendency of flooding in the nearby communities. This research seeks to identify these changes and their relative human cause to see if mitigation methods could be implemented in order to prevent the occurrence of a major flood disaster

1.2 AIM AND OBJECTIVE OF THE STUDY

The aim of the study is to ascertain the degree of change, anthropogenic activities has brought on the Nworie and Otamiri River morphology The specific objectives of this research are:

1. To evaluate the amount of anthropogenic activities taking place around the Nworie and Otamiri River by conducting land use and land cover change analysis.
2. To investigate key anthropogenic activities that have significant environmental impact on the Nworie and Otamir iRiver morphology.

1.3 SIGNIFICANCE OF STUDY

The significance of this study is to serve as a tool for land use planning in years to come, so as to mitigate errors such as building on flood plains and to serve as a yardstick for future research in the subject of urbanization with regards to the Nworie River catchment.

1.4 SCOPE OF STUDY

This study is limited to land use and land cover change and its degree of influence by investigating the man-made events and processes responsible for change in the current channel morphology of Nworie River.

CHAPTER TWO

LITERATURE REVIEW

2.0 INTRODUCTION

Rivers are the major pathway through which excess water flows to the ocean. Rivers portray its significance in various cultural beliefs for example The Slavs (ancient Slovakian, Ukrainians and Czechs) believe rivers are very important, and that the motion of the water suggest that it was alive (Cotterell, 1999).Rivers have always played an important role in human affairs. All the early great civilizations rose on the banks of large rivers: Mesopotamia sat on the banks of the Tigris and Euphrates; Egypt lay in the fertile valley of the Nile; the Yellow River, called “the Mother River,” was the cradle of early Chinese civilization; and the Indus River on the subcontinent of India was the birthplace of Indus Valley Civilization. Rivers change naturally over time, as a result of climatic and tectonic influences (Tarbuck, Lutgens & Tasa, 2014).

Most rivers in developing countries like Nigeria are subjected to an increase in the amount of pollution load as a result of the inflow of effluents of different kinds from human activities, which have become a major threat to the quality of water (Arimoro & Osakwe 2006). Taniguchi (2015) also suggested that urbanization also increases drainage density through the establishment of manmade drainages, this increases flow velocities of overland and channel flow. In other words, progressive change in land use, vegetation and an increase in impervious surfaces will result to an increase in runoff ratio, the amount of peak discharge and the rate of stream flow (Wel & Oye, 2014) although flood hazard is natural, human modification and alteration of nature’s right of way could constitute a problem, while the disastrous consequences are dependent on the degree of anthropogenic activities and occupancy in vulnerable areas (Ogba and Utang, 2008). Taniguchi (2015) further notes that hydro modification, can induce stream channel erosion, often leading to infrastructure and property damage and degradation of water quality and aquatic ecosystems. That is why understanding the connection between stream morphology and humsn activities is important for storm water management and proper land use..

2.1 STREAM MORPHOLOGY

Most medium to large rivers flow on beds of sediment that they have deposited and can transport again. The unconsolidated sediment in the river valley, lying above the bedrock “basement” of the river, is called the valley fill. Its thickness ranges from just a veneer to hundreds or even thousands of meters. In the case of rivers flowing across areas of the crust that have undergone substantial and prolonged subsidence, the valley fill is buried so deeply that it is at least partly lithified, and the material grades over into what would be considered the “ancient sedimentary record” (the term geologists use for sedimentary rocks that are very old by human standards).

A floodplain is a flat depositional surface adjacent to active river channels that are constructed by river processes and built with alluvial sediments (Latrubesse & Park, 2017). During floods the floodplain receives a layer of fine sediment that settles out of suspension as the flood waters spread over the floodplain and decrease in velocity. If the river is not undergoing net aggradation, then the floodplain builds up to a level where the rate of removal of fine sediment by erosion back into the main channel at times of low water is great enough to strike a balance with the rate of addition of fine sediment from suspension during floods. Most river floodplains are heavily vegetated, and, depending upon climate, are often dotted with shallow lakes and swamps. Floodplains are among the best areas for agriculture, because they continually receive fresh influxes of fertile soil. Alongside many river channels are low ridges called natural levees, formed by deposition of the finer fraction of suspended sediment from flood waters passing across the river banks when the river is above flood stage.

The river channel itself can be characterized most fundamentally by its cross- section shape and cross-section area. The width refers to the distance from bank to bank; obviously the width depends majorly on the river stage as well as on the average size of the river. The depthof the river varies from point to point across the section. A good way of encapsulating the lateral dimensions of the river is to specify the hydraulic radius: the ratio of the cross-sectional area to the wetted perimeter at a given cross section. For a very wide channel with a nearly rectangular cross section, with an approximately level bottom and steep banks, he hydraulic radius is nearly equal to the flow depth. The longitudinal profiles of most rivers are concave upward, as shown in

Abbildung in dieser Leseprobe nicht enthalten

Figure 2.1. The Longitudinal Profile of a typical river. Source: Brown, (2013). pp 12

Source: Brown, (2013). pp 12

As the river grows larger, the ratio of cross-sectional area to wetted perimeter increases. Because the slope of the river depends largely, on the relative magnitude of the downslope driving force of gravity, which is affected by the whole volume of the river, and the upslope resisting force of friction, which is affected by the area of the riverbed, the slope decreases downstream.

Fluvial processes cease where a river flows into a large lake. This is referred to as the base level as introduced by John Wesley Powell (Leopold & Bull, 1979). The base level changes with time: lake levels fluctuate as a consequence of variations in precipitation in the watershed of the river or because the outlet of the lake is eroded downward, and sea level changes, for various reasons and often very substantially, over a great variety of time scales, ranging from decades to tens of millions of years. If base level rises, some of the sediment that’s carried along by the river toward the river mouth is deposited along the way to raise the river bed, thereby establishing a new equilibrium longitudinal profile. If base level falls, the river erodes its bed to adjust toward a new, lower equilibrium profile.

When there is a dramatic change in base level through isostatic rebound, tectonic uplift, a change in catchment area size possibly by a stream capture event the point of change in slope is called a knick point (Moffatt, 2013)

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Figure 2.2 Diagram showing a knick point

Source: Moffiat, 2013. pp 5

The position of a knick point is marked by a waterfall or rapids. Knick points migrate slowly upstream; thereby extending the new, lower longitudinal profile as the river eats its way upstream. If a floodplain has developed in the river valley, the old floodplain downstream of the knick point survives, for a long time, as a pair of terraces above the new, lower river channel Because the difference between old and new equilibrium profiles decreases upstream, other things being equal (the elevations of the highlands in the headwaters of the river are very conservative), the height of this knick point decreases as it migrates upstream. Often, if base level drops abruptly a number of times during some long period of time, more than one knick point is present along the river course, each slowly making its way upstream.

As the river lowers its bed in response to a fall in base level, and at the same time shifts its course laterally, it develops a new floodplain that’s entrenched below the level of the old floodplain. The result is a pair of flat-topped river terraces, one on either side of the river. The slopes at the edges of the modern floodplain retreat without much change in their shape (Easterbrooke, 1999).

2.2 CHANNEL PROCESSESS

2.2.1 EROSION

Erosion is a hydraulic action and is derived from the energy of running water (Matsuda, 2015). Negrel (2014) states that it could affect all the river basin area through various erosion processes.Tarbuck et.al (2014) describes these processes as quarrying (which involves the removal of blocks from the bed of the channel. This process is aided by fracturing and weathering that loosen the blocks sufficiently so they are moveable during times of high flow rates), Abrasion (The process by which the bed and banks of a bedrock channel are ceaselessly bombarded by particles carried into the flow) and corrosion (a process in which rock is gradually dissolved by the flowing water).These processes either widen the channel or deepen the channel. Matsuda (2015) explains that if deepening erosion predominates, a canyon is formed. Lateral erosion forms a channel with a broader river bed.

2.2.2 TRANSPORTION.

The capacity of a river to transport sediment load depends on the water velocity. Streams sort the solid sediment they transport because finer, lighter material is carried more readily than larger, heavier particles. Streams transport their load of sediment in three ways (Tarbuck et.al, 2014). They are corrosion, suspension and traction. Corrosion is the process in which stream water corrodes rocks and brings them invisibly into solution. Such fine materials as clay, silt, fine sand and materials lighter than water are transported in the water or on the water surface without contact with the river bed. This process is called suspension, and materials carried in suspension are the suspended loads.

Suspended load creates the turbidity of stream water. Gravel of larger diameter slides or rolls, and sand hops or bounds on a river bed. These processes are called traction. Sediment load carried by traction is known as bed load (Matsuda, 2015).

2.2.3 DEPOSITION

Tarbuck et.al, (2014) describes deposition as when flow velocity is less than the settling velocity; as a stream’s flow velocity decreases, sediment begins to settle, largest particles first. In this manner, stream transport provides a mechanism by which solid particles of various sizes are separated and an alluvium plain is formed. Deposition occurs whenever a stream slows, causing a reduction in competence. Regions of the stream dominated by deposition are characterized by extended deposition features and the absence or limited occurrence of erosion features (Bizzi & Lerner, 2015) regions such as the lower course of the stream.

2.3 EFFECT OF ANTHROPOGENIC ACTIVITIES ON CHANNEL MORPHOLOGY

Human activities around a river catchment play a major role on the geomorphology of the water body. Some of the effects of the anthropogenic activities on river catchments are:

2.3.1 OBSTRUCTION OF NATURAL FLOW

One common anthropogenic activities on most channels is the Obstruction of the natural flow. River water is one of the major sources of drinking water. With decrease in rainfall and fall in ground water level, the dependency on river for drinking water is increasing (Jatan, Istak & Nibedita, 2015). An example of human induced change in river morphology is dam construction, which alters the ebb flow of fluvial water and sediment, therefore creating or shrinking estuarine channels.

According to Science Learning Hub (2017), dams alter the temperature, flow and sediment in river systems. Reduced flow alters aquatic habitats – reducing or removing populations of fish, invertebrates and plants that depend on the flow to bring food. Reduced flow also decreases tributary stream flow, changing habitats and altering the water table in the stream aquifer.

2.3.2 WATER POLLUTION

Pollution, caused by runoff from agricultural chemicals, is poorly-managed and sometimes out-of-date industrial processes, and lack of adequate treatment for sewage and other urban waste also cause water pollution. The results may include water that is unfit to drink, massive fish kills, and complete loss of underwater plants. Yet many effects of pollution are more insidious, only becoming clear after toxic substances have been building up in the food chain for many years.

Water pollution constitutes ever-increasing problem. By its origin, it is advisable to subdivide water pollutants into three groups [Goudie, Viles, 1997]: 1) municipal wastes; 2) industrial wastes; 3) agricultural wastes. Municipal wastes mainly consist of human faeces and contain relatively few chemical pollutants; yet, they are notable for high concentration of pathogenic organisms.

Communal wastes, or sewage, make approx. 20% of all effluents’ volume, and their share constantly increases as the amount of industrial effluents decreases. They have more or less permanent structure. A person daily produces 65 gram of suspended matter, 8 gram of ammonia nitrogen, 3.3 gram of phosphates, 9 gram of chlorides, and 60-75 gram of organic matter [Rudskiy and Sturman, 2005].

2.3.3 DEFORESTATION AND LOSS OF NATURAL HABITAT

Anthropogenic activities such as farming may lay waste to riparian vegetation in a dire need to provide land space for the growing of crops. This exposes the top soil to agents of denudation, which in turn leads to degradation. Now this loss of vegetation would cause an altercation to the ecology.

Research has been done in this field and majority share the common idea as stated in Ahmed & Dinye (2012) that “water resources has come under a lot of threat in recent years from human activities especially in the urban environment. These human impacts are population growth, rapid physical development and incompatible land use activities”. In addition to the impact of humans, the resource for the conduct of widespread information and awareness programmes has been rather inadequate (Mtisi and Nicol, 2003).Various research have been carried out with regards to the impact of anthropogenic activities on stream morphology. Most of them share a common idea on how human activities impact the stream form

Isik et.al (2008) observed that heavy human activities began in 1975 in the lower Sakarya area and the annual flow in the river reduced by 20% after 1975. As a result of this change, the flow of the river was altered with respect to the various seasons and there was an increase in low flows and a decrease in high flow.

Jiongxin (2004) also investigated the major anthropogenic seasonal rivers in China such as the Lower Yellow River and the Haihe River, and some of their tributaries. He found that, due to strong human activities, some perennial rivers in north China have been changed into seasonal rivers. He explained that these rivers can be regarded as a new category of rivers, and used the term “anthropogenic seasonal river” to describe such rivers.

Clark &Wilcock (2000) research gave rise to a conceptual phrase known as “Reverse Channel Morphology” which simply refers to a downstream decrease in channel size that is contrary to the expected geometry of selfadjusted channels, but is consistent with the presence of partially evacuated sediment remaining. This research explains that from 1830 to 1950 in NorthEastern Puerto Rico land was cleared for agriculture this led to a 50% increase in runoff and sediment load in the channel. Over 50 years later there was a shift in land use from agriculture to industrial and residential purposes. This further elevated runoff but decreased amount of sediment load supplied to the channelthis in turn caused channels to re-adjust in order suit runoff needs.

The work further suggests that Identification of reverse channel morphology along individual watercourses may be obscured in multi-watershed compilations in which other factors produce a consistent, but scattered downstream trend. Identification of reverse channel morphology along individual streams in areas with similar land-use history would be useful for identifying channel disequilibrium and anticipating future channel adjustments.

Gregory (2006) argued that the direct consequences of human on the river channels through engineering works, including channelization, diversion and culverting has been long recognized. Downs & Gregory (2004), had earlier catalogued the major ways in which human influence has affected river channels over the last 5000 years through dam construction, river diversions and engineering since the first phase of the early hydraulic civilisations affected river channels.

Gregory (2006) further noted that there are five major challenges considering human roles on channels: First of all prediction of the nature and amount of likely change at a particular location is not certain, and because the contrasting responses of humid and arid systems needs to be considered, modelling is required to reduce uncertainty, Secondly, feedback effects incorporated within the relationship between changes at channel, reach and network scales can have considerable implications, especially because changes now evident may have occurred, or have been initiated, under different environmental conditions. Third, consideration of global climate change is imperative when considering channel sensitivity and responses to threshold conditions. Fourth, channel design involving geomorphology should now be an integral part of restoration procedures. This requires, fifthly, greater awareness of different cultures as a basis for understanding constraints imposed by legislative frameworks.

Jatan, Istak & Nibedita (2015) research highlighted some anthropogenic activities and there relative impact, some of which are:

1. Barrage construction across the dam to provide irrigational facilities in the agricultural fields especially in the dry season, caused a decrease in the competency and capacity of the river to transport sediment load.
2. Sand extraction is intense in countries subject to urban development and this act caused channel deepening which is often referred to as incision.
3. There is an obstruction of the water flow from the river due to the need of drinking water. Purification plants were built near the river and these plants obstruct the flow of water, thereby causing a reduction in the ability of the river to carry load because of the lack of water currents.
4. Construction work in the river and river banks like bridges caused a sudden flow of unwanted debris from the banks into the river which in turn causes a decrease in channel depth.

Barr (2017) considered anthropogenic activities from a different perspective due to the high level of flooding around the world. The author suggested that an understanding of geomorphology is important, in order to understand urban morphology, an analysis beyond the norms of geomorphic change is required, this means looking past impervious surfaces and into social influence often referred to as human intervention (this refers to channel changes caused by human engineering in order to fit infrastructural need) in river channels which is most often discussed in most studies. The aim of the study was to expand our understanding of urbanized channels by conducting a socio-geomorphologic investigation. That is investigating the natural and policy driven events and processes leading to the current channel form. The conclusion of the research was, not all urban rivers undergo the same type of morphological change due to the difference between local socio-political processes and the local contingency. History is also an important consideration with channel physical attribute which could provide a detailed understanding of urban morphological outcome of a combined interaction of the natural and socio-political circumstance.

CHAPTER THREE

RESEARCH METHODOLOGY

3.0 INTRODUCTION

This chapter deals with the data used in the analysis for the case study with respect to their sources, and the methods used in integrating the data obtained for proper analysis. Documented data was the source of secondary data while primary data was sourced directly from sampled locations within the study area catchment. Both quantitative and qualitative approaches were used in this research

3.1 STUDY AREA

The study area, Owerri is located within latitude 5°17’50”N to 5°32’20”N and longitude 6°58’10”E to 7°3’0”E as shown in Figure 3.1 and covers an area of about 24.88 km2. The area has an annual rainfall of 1900-2900mm and monthly temperature of 25°C at a minimum and 35°C and a maximum. Owerri metropolis area has a tropical wet and dry climate. The north - east trade wind causes the dry season as it advances south wards while the south-west trade wind causes the rainy season as it moves inland towards the north. Dry season starts from November to early March while the rainy season starts from March to October and reaches their peak in September after the “little dry season. Owerri is located in the rain forest zone. The rainfall is characterized by high rainfall in most of the rainy months of the year.

There are various land use patterns in the study area which include residential, commercial and administrative land-uses. The built up of the town is within the confluence of the Nworie and Otamiri Rivers. The commercial market and traditional housing district are both in the central parts of the town while the southern parts of the town are high density residential district. Low density residential area and public establishments and major educational institutions are concentrated in the north east axis of the town. Owerri among other areas in the south-eastern Nigeria is made up of the tertiary geological formation succession. This is built on the coastal plain sand formation during the Miocene epoch of the Cenozoic era. The sediments of the coastal plain were particular, and consolidated and sandy.

The study area lies at the northern section of the eastern coastal lowland, which is characterized by southward dipping slope. To the southwest of the town, the terrain is flat while tolling hills runs in a north south direction to the east at about an elevation of 30m. The vegetation of the basins can be described as secondary forest. The vegetation cover shows a varied combination of different types of plant group which reflect the extent of interference by man on the original vegetation cover. In some parts of the study area, the vegetation cover is marked by the frequent occurrence of the umbrella tree (Musanga decropoides). The southern part of both Owerri is relatively undisturbed. The forest is dense and consists of 3 layers; high dominant trees, low dominant trees, shrubs and herds all interwoven by lianas and climbers. Tress here attains the heights of between25-30 meters. The average population according to the 2006 census is 401,873 and the major occupation of the people is agriculture and small-scale industries.

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Figure 3.1. A map showing the study area

Source: National Space Research and Development Agency (2016)

3.2 LAND USE CHANGE

This section presents primary and secondary techniques of data collection and techniques of data analysis and the procedures used to meet the proposed aim and objectives of the study that sought to determine the temporal and spatial land use changes in Nworie and Otamiri river sub-catchment from 1986 to 2016.

3.2.1 DATA COLLECTION

Primary data was collected using structured questionnaires which was carefully administered randomly by the interviewer to residents and all occupants within the catchment (Appendix).This enabled the researcher to ensure that the respondents were those that were needed to respond to the questionnaire, so as to improve reliability of the data (Saunders, Lewis & Adrian, 2009). The targeted population for the study was 100 residents along the river course which was mapped out in the map of the study area, (see figure 1.1). The sample size of 95 used in the study was based on the formula by UNICEF (1995):-

Abbildung in dieser Leseprobe nicht enthalten

Where:

n is the necessary study sample, t is the confidence level at 95%, p is the estimated number of residents in the catchment and m is the margin of error at 5%.

Data on land cover change was obtained from the Owerri Capital Development Authority (OCDA) along Port Harcourt Road Owerri. Photographs were also taken at various sites to reveal key land use types. During field investigation, the GPS coordinates of the sampled deforested areas was recoded to be used to overlay on the satellite processed data like the Land use land cover. This was adopted as the reconnaissance survey in the study.

Table 3.1 and 3.2 summarizes the locations sampled and their respective coordinates and altitudes.

Table 3.1 GPS coordinates of some locations along Nworie River

Source: Field work by Researcher 2017

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Table 3.2 GPS coordinates of some locations along Otamiri River

Source: Field work by Researcher 2017

Secondary data from satellite imageries including Landsat 4 and Landsat 5, Thematic Mapper (TM) of 1986 and 2000 respectively and Landsat 8 Enhanced Thematic Mapper Plus (ETM+) acquired from path 188 and raw 56 of 2016. The above satellite imageries was obtained from United States Geological Survey (USGS) earth explorer web archive, which was used to generate land use land cover map for 1986, 2000 and 2016.The Landsat imageries are made up of seven bands but only three bands (band 4, 3 and 2 of RGB) were combined for false colour composite which was used for the land use land cover analysis. In order to estimate to near 100 percent of the vegetation lost, the false colour composite was adopted for this study. All the archived Shape files ArcGIS data used for the production of the Administrative maps and local Government Map of Nigeria was acquired from the National Space Research and Development Agency (NASRDA).

Table 3.3 showing the source of Satellite Images

Source: Field work by Researcher 2017

Abbildung in dieser Leseprobe nicht enthalten

3.2.2 RESEARCH DESIGN (Data Analysis)

Land use land cover map from 1986 to 2016 was generated from satellite imageries listed in (table 3.1). False color composite (band 4-Red, 3-Green and 2-Blue) were used to process the images for the years 1986, 2000 and 2016. The above mentioned band were combined and the area of interest was extracted by layer stacking using studies area boundary. Sample signature was created and used for supervised classification adopting maximum likelihood classification scheme. The Land use land cover classification identified five classes namely: bare surfaces, built up area, bare surface, light forest and thick forest. Vectorization of the classified images was conducted in ArcGIS software.

Development of a Classification Scheme

Based on observation of the study area for over 20 years and a reconnaissance survey done during the field work with additional information from previous research literatures in the study area, a classification scheme was developed for the study area after Anderson, Hardy, Roach & Witmer (1967). The classification scheme developed gives a rather broad classification where the land use land cover was identified by a single digit.

Table 3.4 Land use land cover classification scheme

Abbildung in dieser Leseprobe nicht enthalten

Source: Anderson et’al 1967

The classification scheme given in table 3.4 is a modification of Anderson’s in 1967

3.2.3 DATA ANALYSIS AND PRESENTATION

Five main methods of data analysis were adopted in this study

(i) Band combination and image processing
(ii) Maximum Likelihood Classification
(iii) Calculation of the Area in hectares of the resulting land use/land cover types for each study year and subsequently comparing the results.
(iv) Overlay Operations
(v) Change detection of LULC variability

The methods above were used for image processing and identifying change in the land use types. Therefore, they have been combined in this study. The satellite imageries were resampled and classified using the maximum likelihood classifier scheme of Anderson et. al, 1967. The comparison of the different layers was done using the overlay technique in ArcMap. The comparison of the land use land cover statistics assisted in identifying the percentage change and trend of change in the study area between 1986 and 2016.

2.2.0 FIELD SURVEY

2.2.1 SELF-ADMINISTERED QUESTIONNAIRE

The research also used self-administered questionnaire to solicit the individual views of heads of households regarding the research questions. Respondents had equal range of questions to answer under the supervision of the researcher. This was because the questions needed to be interpreted to respondents (because of inability to effective read and/or write) and the replies aggregated by the research hence a more generic name of the “self-administered questionnaire” is referred to as “self-completion questionnaire” Through this, the various responses could be compared and contrasted to establish a pattern of thoughts.

2.2.2 PARTICIPANT OBSERVATION

Participant observation or ethnography was another important data collection technique used to generate qualitative data. Through this technique first-hand information were obtained in relation to the various aspects of the research questions. Majority lived near the water bodies. As a result of their educational background and the proximity of their residence from the water body, they all had a notable comment about the changes that occur on the water body.

Some participants based their comments on religious or superstitious belief.

3.3.3 SAMPLING FRAME AND TECHNIQUE.

The stratified random sampling techniques was used in the study. This method was used to guide the selection of appropriate sample to ensure that, generalization of sample findings are representative of the population which is a key characteristic of all probability sampling techniques. This technique was used to select household heads for the questionnaire administration. The stratification was based on gender (male and female strata), and respondents were then randomly sampled from these strata. The other technique adopted was purposive sampling which Bryman (2008) argues is used to selected subjects based on their relationship with the research questions. This technique was used to identify key informants like traditional rulers and assembly man to conduct the interviews.

3.3.4 TOOLS OF DATA ANALYSIS (SOFTWARE USED)

Software were used for data analysis this research include;

a) ArcGIS – This was also used to compliment the processing and display of the data
b) ERDAS 2014 – This was used for the development of land use land cover classes and for change detection analysis of the study area.
c) Microsoft word – was used basically for the presentation in the research.
d) Microsoft Excel was used in producing the bar graph.

CHAPTER FOUR

RESULT PRESENTATION AND DISCUSSION

4.0 INTRODUCTION

This chapter is concerned with the presentation of the result of this study. The result presented here are in accordance with the research questions that guided the study. Results of the various image analyses done are presented in the form of maps, charts and statistical tables reflecting the static, change and projected land cover of identified classes within the watershed zone.

4.1. IMAGE CLASSIFICATION ACCURACY

The image classification accuracy as derived for this classification, and results obtained are summarized in Table 4.1 below

Table 4.1 Summary overall classification of accuracy and kappa coefficient

Abbildung in dieser Leseprobe nicht enthalten

Source: Field work by Researcher 2017

As shown in the table 4.1, the lowest overall classification accuracy was 82.5% and the highest was 86.8%. The highest kappa coefficient was 0.83 and the lowest was 0.80.

4.1.1 LULC CLASSIFICATION MAPS AND OUTPUT

The Land use/Land cover distribution maps and area coverage in percentage of each LULC types for year 1986 and 2016 are presented in figures 4.1 and 4.2:

Abbildung in dieser Leseprobe nicht enthalten

Figure 4.1: 1986 LULC Classification of the Study Area.

Source: National Space Research and Development Agency (1990)

Abbildung in dieser Leseprobe nicht enthalten

Figure 4.2 2000 LULC Classification of the Study Area

Source: National Space Research and Development Agency (2002)

Abbildung in dieser Leseprobe nicht enthalten

Figure 4.3 2016 LULC Classification of the Study Area.

Source: National Space Research and Development Agency (2017)

4.1.2 LAND USE LAND COVER DISTRIBUTION.

The land use land cover distribution for each study year as derived from the classification are presented in the table below:

Table 4.2 Land Use Land Cover Distribution (1986, 2000 and 2016)

Abbildung in dieser Leseprobe nicht enthalten

Source: Field work by Researcher 2017

Abbildung in dieser Leseprobe nicht enthalten

Figure 4.4: LULC Change Distribution (1986 - 2000 – 2016)

Source: Field work by Researcher 2017

Table 4.3 LULC Change between 1986, 2000 &2016

Abbildung in dieser Leseprobe nicht enthalten

Source: Field work by Researcher 2017

Table 4.2 above represents the area of each land use and land cover category for both of the study years. The land use and land cover types for the study area were described as built-up area, water body, thick forest, light forest, and bare surface. Of the total area in this classification, thick forest covered the largest percentage in 1986 with an estimated area of 21953.1 Ha (58.8%), reducing to 15047.7 Ha in the LULC result of 2000, i.e. about (40.3%). The thick forest loss continued as it further reduced to 11994.9 Ha, in 2016 which was about 32.1% of the entire LULC. The result revealed that thick forest in the study area was lost with a magnitude of about 9958.1Ha. (26.7 %) in 2016 to other land cover, that is a huge loss.

Light forest covered about 5627.2 Ha. (15.1%) in 1986. In 2000 LULC classification result, the area covered with light forest was observed to increase to a total of 10081.2 Ha. (27.0%). In 2016, the light forest further increased to 12000.1 Ha. (32.1%) of the entire area coverage. There was a significant increasing trend observed in Built-up Area. A total of 6184.1 Ha. (16.6 %) in 1986 was observed to be occupied by Built-up area, which increased to 8483.7 Ha. (22.7%) in 2000 and there was a further observed increase of 9954.5 Ha. The Built-up Area generally increased with a total area of 3770.5 Ha. Which was about 10.0% of the entire area converted to Built-up area within the study year from 1986-2016.

Apart from built-up areas, the forest cover was observed to be reducing simultaneously in the LULC results, every other land use land cover experienced deficit and these include thick forest as explained above. Water bodies suffered the worst land cover changes: Water body (Otamiri River and Nworie River) occupied about 468.0Ha i.e. about 1.2 % in 1986. In the year 2000 the river increased to about 880.7 Ha (2.3%) and later in 2016, the water body reduced to about 698.69Ha making about 1.9% of the entire land cover.

4.1.3 RESULT OF RESPONDENTS

Abbildung in dieser Leseprobe nicht enthalten

Figure 4.5: Activities of the dominant in the area

Source: Field work by Researcher 2017

The respondents described that the major activities within the surveyed area was sand excavation. This is because the study focused on the riverine areas where there is significant changes in the stream morphology. 34 percent of the respondents strongly agreed that farming was the major activities in the area. However this is due to much farmers who plant at the riverine areas all round season for steady irrigation. Other activities were automobile mechanics and civil servants in the study area

Abbildung in dieser Leseprobe nicht enthalten

Figure 4.6: Ratio of land owners surveyed

Source: Field work by Researcher 2017

Abbildung in dieser Leseprobe nicht enthalten

Figure 4.7: observed land uses by the owners

Source: Field work by Researcher 2017

From the respondents, 90 percent of land owner stated that over the past one decade their land was previously a farmland or forest vegetation which was previously used as farmlands on two-year interval. However due to need to own a house and based on the demand for survival the population of the town is increasing daily putting more pressure on Land.

The situation has also increased the pressure placed of river-bed, sand is excavated daily thereby disturbing the aquatic ecosystem and their habitats making it difficult for the river to have the natural purification process making the river turbid almost all year round. Now this small particles in the river act on a micro level thereby eroding minute particles of the bank wall. The sum of all the individual micro corrosion would result to a major corrosion of the river bank and river bed.

Abbildung in dieser Leseprobe nicht enthalten

Figure 4.8: Changes in the study area

Source: Field work by Researcher 2017

Figure 4.9 revealed the respondents observed the changes within the study area, few respondents who engage in sand mining noted that there is severe land slide occurring in most of their work site, the can be attributed to over exploitation of the water and land resources due to increasing demand in the developing city of Owerri. Thus, due to current urban expansion. Most of the land owners and the indigenes have resorted to exploring lands of the riparian zone for agricultural activities and thus erosion was their greatest nightmare. Also due to unmanaged drainage system, overland flow was discovered to flow out of drainage channels causing erosion and destruction of roads and farmlands

From “question 5 part C in the questionnaire” the respondents revealed that the color of the water body has always been dirty and brownish in color. Even the respondents who has lived 11-30 years strongly agreed that the color of the river has been dirty both in rainy and dry seasons. They agreed that this was as a result of the water body serving as a receiving river channel of the city overland flow and waste water during rainy and dry season respectively.

Abbildung in dieser Leseprobe nicht enthalten

Figure 4.9: Respondent’s observation on changes in river channels

Source: Field work by Researcher 2017

The greater percentage of the respondents agreed that the river channel is widening, the reported that this could be attributed to dredging and river sand mining which is a daily occurrence in the study area. Majority of the respondents were artisans and laborers dwelling at the riverine area for a daily bread thus they said they remit tax to the government for their activities.

4.1.4 RESULT OF FIELD MEASUREMENT

The average width of River Otamiri FUTO is 33.0m, Nworie River at Warehouse junction is 100m and Nworie River at Akwakuma/New road is 58m width. Figure 4.10 illustrates a morphological map of the Otamiri and Nworie

River.

Abbildung in dieser Leseprobe nicht enthalten

Figure 4.10 a map showing the morphological map of River Nworie and Otamiri

Source: Field work by Researcher (2017)

4.2 DISCUSSION

4.2.1 LAND USE CLASSES AND CHANGE IN LAND USE LAND COVER

An important aspect of change detection is to determine what is actually changing to what i.e. which land use class is changing to the other. This information will reveal both the desirable and undesirable changes and classes that are “relatively” stable overtime. This information will also serve as a vital tool in management decisions. This process involves a pixel to pixel comparison of the study year images through overlay.

In terms of location of change, the emphasis is on hydrological phenomena in this case water bodies. Fig 4.1, Fig 4.2 and Fig. 4.3 shows this change between 1986 and 2016.

However, the most significant changes occurred in the land use land cover dynamics of light forest, Water bodies and Wetlands. It is clearly observed from the result that the light vegetation areas might be farmland and the extent at which Forest cover is being converted to Built-up areas is alarming. The clearing of vegetation (Thick forest, Light forest (possibly farmland), and riparian vegetations) has resulted in the increase in floodplain areas, leading to the deposition of sands. What can be inferred further from these land cover changes is that the Otamiri and Nworie River Basin is now vulnerable to severe gully erosion with net contribution of sediments to the river system which affects its flow capacity making them to ephemeral. The cumulative effect of vegetation clearance whether thick, light or riparian showed an overwhelming increase in floodplain in 2000 and 2016.

4.2.2 EFFECTS OF LAND USE LAND COVER CLASSES ON THE HYDROLOGICAL REGIME

In 1986 water bodies occupied an area of 880.69 Ha in 2016 it decreased to about 468 Ha,. This represents a loss of about 412.7 Ha. This occurrence is primarily as a result of erosion at the river banks. This ultimately has had a negative impact on the hydrological regime of the river system.

The riparian zones of the upper section of the River has heavily been lost to sand excavation and river sand mining, from these activities, if close to water body can be a source of sediment load to the river, causing river bed erosion.

Downstream of the Otamiri and Nworie River Basin, major riparian vegetation retain water in the form of back swamp floods, vernal pools and extended flood plain waters after the seasonal floods, but when there is a depletion of these vegetation, the capacity to hold water is often impeded and the area quickly dries up leading to the reduction in water channels which is reflected in the hydrological regime of the basin, during Rainy seasons, flood events occur in magnitude higher than the previous this is because the riparian trees and vegetation that would have acted as buffers to reduce the flood have all been removed by farmers, sand excavators and miners in stream.

During the wet seasons, discharge is swift and fast flowing, the channel width is increased and stage (volume) quite high as a result of floods. The reverse becomes the case in dry season. There is no adequate vegetation to reduce evaporation, so the water rescinds, the flow becomes slow, stage greatly reduced and coupled with in stream mining activities downstream, and the water becomes turbid.

More also physical degradation of soil (poor structure, compaction, crusting and waterlogging) in the riverine areas affect the terrain and the physical nature of the water body. Excessive rainfall, or excessive irrigation, resulting in the passage of water through the soil profile through deep percolation will carry with it soluble nutrients, particularly nitrate, sulphate and boron, etc. thus, polluting the water body.

4.2.3 MORPHOLOGY OF THE NWORIE/OTAMIRI RIVER

From the field operation in the study area it has been observed the present form of the river is strongly dependant on the amount anthropogenic activities in the area. There is a higher concentration of activities such as bank farming, dredging and sand excavation around ware house as compared to Akwakuma. This has caused a widening in the river morphology due to erosion of the river bank as a result of soil instability caused as a result of this continuous human activities. River Nworie is a victim of anthropogenic activities although the most prominent is the cutting down of riparian vegetation for the sole purpose of raising buildings. This human activity is most predominant in river Otamiri flowing through Federal University of Technology, Owerri. There are notable changes on the river bank as a result of mass movement. As shown in the figure 4.11 is a part of the bank of the Otamiri River, which is subject agents of denudation as a result of farming.

Abbildung in dieser Leseprobe nicht enthalten

Figure 4.11 an image showing an eroding part of the Otamiri River

Source: Field work by Researcher (2017)

CHAPTER 5

SUMMARY AND CONCLUSION

5.1. SUMMARY

From the data analysed, findings suggest that changes in land use and land cover has had effect on the morphology of Nworie and Otamiri River catchments. Satellites photographs of the past 30 years from 1986 to 2016 were analysed and five major land use/land cover classes were identified within the catchment, namely; Water Body, Bare Surface, Built-up Area, Light Forest, and Thick Forest. Analysis of images was done in two sets, images gotten from 1986 to 2000 were classified in one category while images of 2000 to 2016 in another.

From analysis the findings are; the water body experienced a 1.1% increase in area covered from 1986 to 2000, while there was a 0.46% decrease in land area covered by 2000 to 2016. Bare surfaces experienced a decrease from 1986 to 2016, 0.7 % and 0.41% in 1986 to 2000 and 2000 to 2016 respectively. Built up areas are portions of land dedicated to buildings such as residential apartments, office structures etc. Built up area increased from 1986 to 2016, a 6.1% rise in 1986 to 2000 and a 3.94% rise in 2000 to 2016. There was a percentage increase in the amount of land covered by light forest as a result of the relative decrease in the amount of thick forest. The values stand at 11.9% and 5.14% increase of light forest from 1986 to 2000 and 2000 to 2016 resp0ectively. While thick forest decreased by 18.5% and 8.7% from 1986 to 2000 and 2000 to 2016 respectively.

The spatial increase and decrease in land use and land cover classes stated above is majorly as a result of human activities around the catchment. From the questionnaires distributed around the study area major anthropogenic activities identified were Sand Mining, farming, mechanic workshops and civil service. Over 54% of the respondents suggested Sand mining as a major human activity in the study area, 34% suggested farming while 8% and 6% suggested mechanic workshop and civil service respectively.

5.2 CONCLUSION

The findings of the study indicate that there has been spatial change in land use over the years in the sub-catchment. This change was characterized by both increase and decrease land area covered by Water Body, Bare Surface, Built-up Area, Light Forest, and Thick Forest. This study has shown that river bank erosion, loss of riparian vegetation and land sliding occurs along the banks Nworie and Otamiri river catchment. This subjected the river channel to widening, and narrowing in some regions of the bank depending on the amont of human activities. These changes depend on the course of the river, that is widening is more predominant in the upper course of the river while narrowing is more predominant in the lower course of the river because at this stage of the river, the most predominant river process is deposition.

5.3. RECOMMENDATIONS

1. Environmental awareness programs should be set up in order to educate residents on the impact of anthropogenic activities on stream morphology.
2. Monitoring agencies should be set up by the government to help enforce rules that maintain the morphology of the river basin.

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APPENDIX

QUESTIONNAIRE

Dear Respondent

Department of Environmental

Technology,

Federal University of Technology

Owerri

P.O. Box 1526 Owerri

10th September, 2017.

I am a final year student of the above address currently undertaking a project on ―Anthropogenic impacts on Stream morphology: A case study of Nworie River. I request you to kindly respond to this questionnaire. Your responses will be held in confidence and used for academic purposes only. Thank you in advance. Okoroafor Johnpaul.

Questionnaire No…

Sampling Station…

PART A: Personal Details Gender of Respondent: Male [ ] Female [

]

Age: 1[ ]. Below 24. 2[ ]. 25-34. 3[ ]. 35- 44. 4[ ]. 45-54. 5[ ]. 55

& Above 65

Marital Status: 1[ ] Single 2[ ] Married. 3[ ] Widow/Widower. 4[ ]

Others

Education Level: 1[ ] None 2[ ] Primary 3[ ] Secondary 4[ ]

Tertiary

Occupation:

PART B: Socio-Economic and Land Use Data

1. How long have you lived/farmed in this area? 1[ ] 1-5yrs, 2[ ] 6-10yrs, 3[ ]

1130yrs, 4[ ] 31-above

2. Do you own land? Yes [ ] No [ ]

3. If yes, how big is it?

A) Less than 0.5 Hectare. B) 0.5 Ha. C) 1 Ha. D) More than 1 hectare

4. How far is your Land/House/Office from the river? 1[ ] Next to the river bank. 2[ ] 100-250m 3[ ] 250-400m 4[ ] No Idea,

5. What are the major human activities within your Area?

..

6. What have you currently used your land for?

7. is this the same way you have utilized your farm even in the past years?

Yes [ ] No [ ]

8. If the answer is no, what changes have you made as pertains to land use?

a) What land use has been stopped completely.

b) What land use has increased in size over the years

9. What is the portion of land that you have devoted to each one of the land uses mentioned above?

10. What was the land use/cover when you acquired the land/started farming on this land?

PART C: River Flow, Erosion and Morphology

1. Has the fertility of soils on your farm increased, reduced or has remained the same since you acquired the land/moved to this place?

2. If it has decreased, what could be the reason(s)?

3. Have there been any of the following incidences at the river bank/ in your farm/area? A) Soil erosion [ ], B) Land sliding [ ], C) Caving in of land [ ], D) Flooding [ ], E ) Removal of forest along river bank [ ] 4. If yes, when did it/ does it occur?

5. What is the color of water? a) During rainy season? .. b) During dry season? .

6. Is this the same color of the river in the past few years? a) Yes [ ] b) No [ ]

7. What is the level of the water in the river during? A) Rainy season? I) Higher [ ] I) Normal [ ] III) Lower [ ] B) Dry season? I) Higher [ ] II) Normal [ ] III) Lower [ ]

8. Is this the same level the river used to get in the past few years?

a) During the dry season? Yes [ ] No [ ] b). During the wet season? Yes [ ] No [ ]

9. If no, what used to be the water level? (a) Rainy season? .. (b)

Dry season? ...

10. Has the river channel changed in any of the following ways since you came to this place?

1) Widening [ ] 2) Narrowing [ ] 3) Shifting [ ] 4) unchanged [ ]

11. What are the major drivers of the changes in the river channels?

12. Please list the major activities within the

River?

Thank you for Responding to this Questionnaire.

[...]

66 of 66 pages

Details

Title
Effects of Anthropogenic Activities on Nworie and Otamiri River
Subtitle
A Case Study
College
Federal University of Technology, Owerri
Course
Environmental Technology
Author
Year
2019
Pages
66
Catalog Number
V457354
ISBN (Book)
9783668911413
Language
English
Tags
effects, anthropogenic, activities, nworie, otamiri, river, case, study
Quote paper
Johnpaul Okoroafor (Author), 2019, Effects of Anthropogenic Activities on Nworie and Otamiri River, Munich, GRIN Verlag, https://www.grin.com/document/457354

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