We looked at the sustainability of the onsite approach using the triple bottomline approach. We wanted to see what it takes a solution that it acceptable in the environmental domain to be acceptable also in the economic and social dimensions. We selected two types of flood control mechanisms for the study. One is the decentralized online systems consisting of infiltration galleries. The other one is centralized water retention structures that would collect excess stream flow and retain it till the floods subsided along the riverside.
The environmental constraint was the containment of 1:5 year return period rain induced floods. Then we considered measures consisting of 100% distributed measures to 100% centralized measures and in between combinations that can accomodate the environmental constraint. Then we computed the cost of installation for each of these combination and found that there is an optimal combination of centralized and distributed systems that will give the minimum cost solution.
Then to assess we surveyed 1000 households asking if they are willing to install infiltration facilities at their households. For 500 of the participants we also distributed a DVD highlighting the advantages of the infiltration systems and the environmental benefits they bring. The results were very revealing. Only 17% of participants who were not informed of the benefits were interested to deploy the systems, but once they were informed 37% were willing to participate.
This shows that we need to place a very strong emphasis in motivating and keeping public engaged if we are to succeed in adopting decentralized measures.
