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Harrison Grierson was commissioned by Greater Wellington
Regional Council (Greater Wellington) to develop a model of
rainwater tanks in the urban environment for the cities in the
Wellington region; Lower Hutt, Upper Hutt, Porirua and Wellington.

This report presents the findings for Upper Hutt and discusses the
costs of installing rainwater tanks. The model is set up to calculate
the volume of water in the tank each day using the rainfall over
the roof area as the flow into the tank and the household demand
as the flow out of the tank. The tank was assumed to supply only
outdoor usage and toilet flushing.