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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Rainfall intensity, kinetic energy and erosivity of individual rainfall events on the island of Mauritius

Mongwa, Themba January 2011 (has links)
On most tropical volcanic islands the risk for soil erosion is enhanced due to a complex topography, high intensity rainfall and the exploitation of land for agriculture. Mauritius is a typical maritime tropical volcanic island with a distinct elevated interior. Rainfall is dominated by tropical weather systems and trade winds and the island is under intensive cultivation. Rainfall depth, duration, intensity, kinetic energy and erosivity were analysed for 385 erosive rainfall events at five locations over a five year period (2004 to 2008) on the island of Mauritius. Two stations located on the west coast and three stations sited on the Central Plateau above 550 m a.s.l. are used to provide detailed rainfall data at six minute intervals. Erosive storm events, defined here as a total rainfall exceeding 12.5 mm and a maximum 6-minute intensity exceeding 25 mm/hour, are found to differ markedly between the coastal lowlands and the elevated interior with regards to the frequency, the total rainfall generated, the duration, total kinetic energy and total erosivity of individual events. However, mean kinetic energy, mean and maximum rainfall erosivity (EI30) and maximum intensities (I30) from individual erosive events do not show this distinct differentiation. Erosivity measured during summer exceeds that recorded in winter, but the data indicate that large percentages of winter rainfall on Mauritius are defined as erosive and non-tropical cyclone rainfall can pose a substantial erosion risk. In this maritime tropical environment with its elevated interior, soil erosion risk occurs from storm scale to synoptic scale rainfall events and extreme events generate the bulk of the erosivity. Findings show that using rainfall records at an event scale within soil erosion risk assessments on tropical islands with a complex topography will increase the effectiveness of erosivity estimates

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