Earth Today | Research paper champions rainwater harvesting
On the heels of the World Water Day 2021, celebrated on March 22, there is a new research paper that champions a relook at rainwater harvesting (RWH) as one option for secure water storage and security for the Caribbean.
“Whilst there are many handbooks and practical how-to guides for designing and implementing household RWH systems, the uptake has not been what has been hoped for. Even in those jurisdictions where there are statutory requirements to install storage for rainwater, such as in The Bahamas, Barbados, etc, the actual use has been low. The issue is then not one of technology but, rather, of cost, maintenance, a lack of interest, and of incentives,” notes Anika Cole and Dr Adrian Cashman, authors of the Global Water Partnership-Caribbean perspectives paper, titled Status, need and role of freshwater storage in the Caribbean.
At the same time, the duo write that water utilities have, over the years, seen RWH systems as competition, leaving them unwilling to get involved in their provision. The researchers suggest there is a basis for a change in attitude.
PERSONAL TANK PROGRAMME
“In Barbados, the water authority is seeking to roll out a Personal Tank Programme (PTP) as a response to interruptions in supply, and, hence, to ensure water availability to affected households. The PTP has two strands, one to support vulnerable households and the other to make low-cost financing available to encourage uptake through a revolving fund. The catch is, though, that this is a loan which must be repaid, there are no other financial benefits, rebates or other incentives offered; households still must pay their water bill, interruption or not. Whilst some have suggested that this could be an extension of services provided by utilities, based on experience to date, only better-off and sustainability-minded households are likely to invest, in the absence of regulatory or financial incentives,” they said.
Cole and Cashman propose a solution, given prevailing climate change realities.
“An alternative approach, which has not yet been trailed, might be for water utilities to consider RWH as a climate change adaptation in the form of distributed storage. Climate change is expected to decrease water availability from existing sources and to increase variability, whilst water demand is anticipated to increase in most countries. Water utilities have several response options; whilst not dismissing the role of demand management for the supply side, this means looking for additional sources,” Cole and Cashman write.
Further, they insist that there is value in the pursuit.
“In circumstances where the economic cost of developing distributed storage harnessing rainwater is lower than other alternatives, then this should be seriously considered as an option for a water utility – the implication being that the cost of implementation would be borne by the utility. Indeed, it could also be the case that households agreeing to participate would receive some form of incentive along the lines of a renewable energy feed-in tariff, to offset domestic use,” they write.
“For the utility, the potential benefits, apart from deferring the need to develop new sources, could be a reduction in operational costs such as treatment and energy. Of course, there are many caveats that would have to be addressed, the existing concerns over RWH among them, and as with innovation, many issues to be addressed,” Cole and Cashman add.
“The harvesting of rainwater has been with us for a very long time. Traditional approaches, whereby it forms part of household storage and supply, look set to continue, and with growing concerns over climate change and water scarcity, interest and uptake may well grow. However, there is at the same time an emerging, state-led approach which sees RWH as a disaster–resilience and risk-reduction measure to support communities. There is the transformative approach which redefines RWH as a business opportunity for water utilities to extend the scope of services they provide to customers and consumers. In this, water storage is reconceptualised from being a matter of private initiative at an individual level to a public initiative at the corporate level,” they said further.