International Rainwater Cistern Systems Conference
Khon Kaen, Thailand
- January, 1987
Section C: Design
Analysis of Rainfall Patterns for the Design of Rain
Catchment Water Supplies an a Tropical Wet/Dry Season Climate
Guenther E. Seidel, D.I.C.
Rural Water Supply Engineer
Department of Health
P.O. Box 3991
Papua New Guinea
In Papua New Guinea extensive rainfall records are available
but they are not computerized. A method was needed which allowed a sufficiently
thorough analysis yet kept data coding at a manageable level.
A two phase approach was adopted: In phase one monthly
rainfall totals for 38 representative stations and continuous record lengths of
around thirty years were analysed to yield probability distributions of the
occurrence and severity of dry periods. The whole country was then zoned into
seven distinctive dry period rainfall regimes. Phase two of the analysis
consisted of numerical simulations of rain catchment supplies using actual
daily rainfalls for representative periods for each of the seven zones
identified in phase one. Two types of simulation were run: One for standalone
systems the other for systems with supplementary topups from external sources.
The results are a map of Papua New Guinea showing the seven
zones and sets of design tables for each zone. Tabulated are the percent
reliability of a standalone system and the number of topups required, both as
functions of catchment area and storage volume.
The computer programmes used could be run on most
microcomputers using the CP/M80 operating system.
PDF of full document (16pp, 670kb)
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