THE INFLUENCE OF RAINFALL DURATION ON SPLASH PRODUCED FROM A LOAMY SAND SOIL

ABSTRACT
At the event of soil erosion, rain splash erosion supplies materials for subsequent transportation and entrainment. The influence of rainfall duration on splash produced from a loamy sand soil in Camp area of Abeokuta, Ogun State was studied in the laboratory using a laboratory rainfall simulator. The study area is always subject to serious erosion. The objectives of the study are to analyze the characteristics of splash erosion on the soil due to different rainfall duration at different compaction levels. Soil samples were collected from the top 20cm depth of the soil profile, dried and sieved to pass through 2mm sieve. Rainfall intensity of 118.75mm/hr similar to tropical rainfall intensity was used to determine the splash produced by the soil for 5, 10, 15, 20 and 25 minutes with compaction levels of 5, 10, 15 and 20 proctor compaction blows respectively at 12% moisture content.
The results indicated that splash detachment increased with high duration of rainfall up to 15 minutes and further duration of rainfall produced insignificant difference in splash produced up to 25 minutes when the experiment was stopped.
The amount of soil particles that were detached was weighed and the implications of the results obtained are discussed. The amount of soil particles detached during rainfall event varies with the duration of rainfall. The result of the experiment shows that splash erosion is critical for the first 15 minutes of rainfall duration. Also, the compaction level of the soil is a factor that determines the amount of particles detached, the more compacted the soil the less the quantity of soil particles detached.
TABLE OF CONTENT Title page Certification Dedication Acknowledgement Abstract Table of content List of plates List of figures
CHAPTER ONE INTRODUCTION 1.0   General Background 1.1   Problem Statement 1.2   Objective
CHAPTER TWO LITERATURE REVIEW 2.0   Rainsplash detachment and transport 2.1   Effect of rainfall duration on soil erosion 2.2   Water Erosion 2.2.1 Sheet Erosion 2.2.2 Rill Erosion 2.2.3 Gully Erosion 2.2.4 Slumps and Slips 2.3    Erosion and Agriculture 2.4    Erosion and Forestry Operations 2.5    Erosion and Urban Environments 2.6    Erosion and Recreational Impacts 2.7    Economic Impacts
CHAPTER THREE MATERIALS AND METHOD 3.0    Study area 3.1    Materials 3.2    Particle size analysis using the hydrometer method 3.2.1 Materials 3.2.2 Procedure 3.2.3 Calculations 3.2   Compaction 3.2.1 Apparatus 3.2.2 Procedure
CHAPTER FOUR RESULTS AND DISCUSSION 4.0   General 4.1   Rainfall intensity in relation with height of simulator 4.2   Rainfall intensity in relation with soil particle detachment
CHAPTER FIVE CONCLUSION AND RECOMMENDATION 5.0   Conclusion 5.1   Recommendation        REFERENCES        APPPENDICES