Transcription of Chapter 5 SURFACE WATER - WHO
{{id}} {{{paragraph}}}
Example: confidence
Chapter 5 SURFACE WATER - WHO
Chapter 5 SURFACE WATER SURFACE WATER originates mostly from rainfall and is a mixture of SURFACE run-off and ground WATER . It includes larges rivers, ponds and lakes, and the small upland streams which may originate from springs and collect the run-off from the watersheds. The quantity of run-off depends upon a large number of factors, the most important of which are the amount and intensity of rainfall, the climate and vegetation and, also, the geological, geographi- cal, and topographical features of the area under consideration. It varies widely, from about 20 % in arid and sandy areas where the rainfall is scarce to more than 50% in rocky regions in which the annual rainfall is heavy. Of the remaining portion of the rainfall. some of the WATER percolates into the ground (see "Ground WATER ", page 57), and the rest is lost by evaporation, transpiration and absorption.
of nuisance mosquitos and for Aedes aegypti, the mosquito vector of yellow fever in many areas of the world. Such conditions may be avoided by keeping the drains in good repair and by giving them diagonal slope towards the cistern. Frequent inspections will …
Loading..
Tags:
Information
Domain:
Source:
Link to this page:
Please notify us if you found a problem with this document: