1st International Conference on Rain Water Cistern Systems
Honolulu, Hawaii, USA - June 1982

Section 3: Design, Cost, And Policy

Page 135

Optimal Catchment Design by Marginal Analysis

Richard J. Heggen
The University of New, USA

Rainwater Catchment Design

In many regions, roofing and cisterns provide a simple hygienic household water supply (Black and Popkin 1967; Bonilla 1967; Gillis 1967; McJunkin 1969; Ree 1976; Roberts 1967; Wagner 1959; Watson 1915, pp, 278-279; Watt 1978; USPHS 1962). An optimal allocation of resources for construction of such household rainwater catchment systems may be determined from basic engineering principles. Computer simulation may be used to investigate the effect of alternative combinations of rainfall, catchment area, storage volume, and water use rate on the adequacy of supply. Marginal economic analysis may be used to find that scale of facilities maximizing net benefits. Optimal system design includes: (1) precipitation synthesis, (2) water deficit calculations, (3) isodeficit curve construction, (4) isoquant analysis, and (5) optimal scale identification.

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