Rainwater Harvesting (RWH) Systems: Is the Conservation of Water in Colombo Urban Areas Worth It?

Abstract

In Sri Lanka, the wet zone of Colombo and other urban areas usually experience urban flooding situations. Furthermore, the urban setting is rapidly changing. The community perceives flood control and water conservation relatively poorly. Rainwater harvesting is a low-impact development (LID) method to control urban flash flood situations. However, considering people’s interest in and awareness of rainwater harvesting (RWH), it was found that RWH is a lost factor in urban conservation. Therefore, using economically attractive choices, this study estimated the trade-off of residents practicing RWH in urban areas affected by high surface water runoff. The study’s selected area was the Thimbirigasyaya Divisional Secretariat Division (DSD) flooding spots, an ideal location to estimate the preferences/trade-offs of individuals regarding rainwater harvesting practices. This estimation was calculated using a choice experiment (CE) method, which is an economic valuation method. Under this method, the conditional logit model was used to analyze people’s preferences. The results showed that people are motivated and prefer to use RWH due to selected attributes in the field survey. This promising result implies that individuals prefer to use the RWH system as a method of stormwater management and water conservation. Moreover, most residents are willing to adopt these systems looking at their monthly water bill reduction and as promoters of green building concepts.