TABLE OF CONTENTS

Title page    –         –         –         –         –         –         –         –         –         i

Certification          –         –         –         –         –         –         –         –         ii

Dedication   –         –         –         –         –         –         –         –         –         iii

Acknowledgement           –         –         –         –         –         –         –         iv

Table of Content    –         –         –         –         –         –         –         –         v

CHAPTER ONE : INTRODUCTION       –         –         –         –         1-3

CHAPTER TWO: FACTORS AFFECTING WATER SEDIMENT

2.1 Weathering      –         –         –         –         –         –         –         –         4-5

2.2 Temperature    –         –         –         –         –         –         –         –         5-6

2.3 Silting    –         –         –         –         –         –         –         –         –         7-9

2.4 Waste Deposition       –         –         –         –         –         –         –         8-9

2.5 Water current   –         –         –         –         –         –         –         –         9-10

CHAPTER THREE: THE ROLES OF WATER SEDIMENT IN HUMAN HEALTH       

3.1 Habitat/Deposit for Benthos –         –         –         –         —       –         11

3.2 Source of Nutrient to Aquatic Plant and Benthos         –         –         11-12

3.3 The Impacts of Sediment on the Chemical Composition

of the Overlying Water    –         –         –         –         –         –         12-13

3.4 The Rate of Sediment Growth       –         –         –         –         –         13-14

3.5 Impact of Sediment on Human Health     –         –         –         –         14-15

3.6 Impact of Sediment on Aquatic Habitat/Fishes  –         –         –         16-17

3.7 Management Options –         –         –         –         –         –         –         17-18

CHAPTER FOUR: SUMMARY AND CONCLUSION

4.1 Summary         –         –         –         –         –         –         –         –         19

4.2 Conclusion       –         –         –         –         –         –         –         –         20

REFERENCES

CHAPTER ONE: INTRODUCTION

Sediment is the loose sand, clay, silt and other soil particles that settle at the bottom of a body of water. Sediments can form from soil erosion or from the decomposition of plants and animals. Wind, water and ice help carry these particles to rivers, lakes and streams (Griffiths et al., 2006).

Sediment transfer from continents to oceans via rivers is one of the important processes regulating river-bank stabilization, soil formation, biogeochemical cycling of elements, crust evolution and many other earth-related processes. Due to changes in continental positions during the geologic past, water flow and sediment loads in rivers have also shown variations during different time periods. Recent estimations budget sediment flux from rivers to oceans of about 18×10⁹ tons annually. However, it is estimated that the present-day sediment load in rivers has been greatly altered due to large-scale human perturbations. Factors such as relief, channel slope, basin size, seasonality of rains and tectonic activities control sediment loads in rivers. Human interventions in the form of reservoirs for water storage have impounded and trapped huge sediment loads on the continental parts. Similarly, land use patterns also had their effects on sediment flux to the oceans (Chakrapani, 2005).

Sediment entering water bodies degrades the quality of water for drinking, wildlife and the land surrounding streams in the following ways:

Sediment fills up storm drains and catch basins to carry water away from roads and homes,  which increases the potential for flooding; Water polluted with sediment becomes cloudy, preventing animals from seeing food; murky water prevents natural vegetation from growing in water; sediment in streams beds disrupt the natural food chain by destroying the habitat where the smallest stream organisms live and causing massive declines in fish populations; sediment increases the cost of treating drinking water and can result in odour and taste problems; sediment can clog to fish gills, reducing resistance to disease, lowering growth rates, and affecting fish egg and larvae development; Nutrients transported by sediments can activate blue-green algae that release toxins and can make swimmers sick; sediments deposits in rivers can later alter the flow of water and reduce water depth, which makes navigation and recreational use more difficult (Langland and Cronin, 2003).

Several factors affect river sediments, this factors control the volume of deposition of river sediment, its transportation, composition, stability and properties. These factors includes; water current, temperature, silting, waste deposition and weathering.