Causes and Effects of Watershed Degradation

7239 Words Apr 28th, 2011 29 Pages
USING SUITABLE EXAMPLES FROM KENYA, EXAMINE THE CAUSES AND EFFECTS OF WATERSHED DEGRADATION AND SUGGEST POSSIBLE INTERVENTION MEASURES

TABLE OF CONTENTS

CAUSES, EFFECTS AND SOLUTIONS TO WATERSHED DEGRADATION

PREAMBLE Page 4

1. INTRODUCTION Page 4 - 6

2. Causes of Watershed Degradation Page 7 2.1 Land degradation 7 - 8 2.2 Deforestation 8 2.3 Removal of vegetation 8 2.4 Shifting cultivation without adequate fallow periods 9 2.5 Overgrazing 9 2.6 Poor farming methods 9 - 10 2.7 Cultivation of marginal lands 10 - 11 2.8 Improper crop rotations 11 2.9 Unbalanced fertilizer use 11 2.10 Pests and diseases 11

3. Underlying causes
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But a watershed is more than a collection of streams and adjacent land areas--it is a natural resource system in which humans and other organisms interact with the land and its associated resources for sustenance, shelter, and security. The physical condition of a watershed, therefore, directly affects the health and well being of natural and social systems within its divides and indirectly affects those systems beyond its divides.

Degradation of a watershed can have various forms: depletion of water resources, soil erosion and land degradation, impoverishment of the vegetative cover, and damage to the infrastructure. Land degradation is responsible for reduction of the vegetation cover. It can be caused by inadequate land management, overexploitation, and reduced soil fertility, but also by climatic factors. A poor vegetation cover leads to a reduced infiltration rate of the water into the soil and to a loss of water through surface runoff. Surface runoff is one of the reasons for the depletion of water resources on the one hand and for soil erosion on the other hand. Most of the surface runoff is not controlled or effectively used and so lost for the community. In order to profit from the rainwater it has either to infiltrate into the soil and be available for crop production or be intercepted and actively used for