Regional rainfall level zoning for rainwater harvesting systems in northern Taiwan

Rainwater harvesting systems had been widely accepted as solutions to alleviate the problems of water shortages. The main objective of this paper is to convert a rainfall station system based on a point concept to one based on a spatial concept in order to cope with the problems of rainfall data. A two-step cluster analysis was used to classify the sample areas into several regions in accordance with rainfall level characteristics and spatial continuity. The acquired rainfall level classification represents the homogeneity of rainfall intensity and duration because of the minimum combined difference within a cluster; the efficiencies of actual potable water savings in an identical rainfall cluster can approximately reflect a specific range with fewer variations because of the similarity of rainfall intensity and duration. This rainfall zoning system would contribute to the standardized regional precipitation database for the rainwater harvesting application.