Continuing water woes ahead
For well over a year now, Barbados has been experiencing what have come to be known as its ‘water woes’; supplies to homes and communities interrupted for days on end, water tasting salty, bans on watering lawns, complaints that Government ministers and the Barbados Water Authority (BWA) are doing nothing and not listening to the people.
Public meetings have been held, even churches getting involved in the debate. So what has brought Barbadian society to this sorry state? We would argue that it is due to a combination of circumstances, some of which are of our own making. Firstly, there can be no doubt that the severe drought that started towards the end of 2014 and increased in intensity during 2015 did reduce the islands water resources – the water available from our aquifers/groundwater.
But this does not explain the rise in outages and supply interruptions. That is down to complacency and years of under-investment in the maintenance and management of the water infrastructure, about which much has been said and written. Is this, though, a glimpse of what the future holds? The short answer is yes and it could get worse, if we ignore the wake-up call we are having. Recent research by Centre for Resource Management and Environmental Studies (CERMES) into the future availability of water to meet the needs of Barbados illustrates the potential scale of the problem we may be facing.
We have been looking at how much water Barbados will need in 2050 and where that would come from, taking into account climate variability and climate change. Although 2050, some 34 years into the future, may seem like a long way off, in terms of how long our water infrastructure has to last and what it must cope with and how long it takes to design and build, it really is not that far away. We have looked at how Barbados’ economy is likely to grow, particularly the tourism sector, and the linkages to global economic changes and, the changes in domestic demand for water as well as that of other sectors such as agriculture and commerce has been factored in.
From these calculations, we have been able to describe four scenarios and the average water demand associated with each of them. Factored into these calculations have been the losses that are experienced from the water supply system, because we know that what comes out of the tap is less than what gets pumped out of the ground and put into the water supply system. This assumes that there are no supply constraints and that all the demand can be met. However, we already know that all of the demand for water cannot be met, otherwise we would not be experiencing shortages.
The next piece of the puzzle was to look at how much water could be safely and sustainably pumped from the ground in the future. That is how much can be taken out without causing seawater to come into the aquifers or for the water levels to drop so that it becomes harder and harder to pump. A bit like a bank balance, making sure that at the end of the month, you have as much in there as you started the month with (or perhaps just a little more).
The amount of water that can be sustainably pumped out depends primarily on the climate; how hot it is, how much it rains and how much gets into the aquifers. To do this, we used the projections of future climate change that have been produced by Professor Michael Taylor’s group at UWI Mona and applied them to a model of Barbados’ groundwater aquifers that was developed for this work. In this way, we have been able to project what the sustainable yield from Barbados’ aquifers is likely to be around 2050. In addition to this, we have added the water produced by the existing Spring Garden Desalination Plant, as this contributes to the available supply.
The results can be seen in the graph and it is worrying to say the least. What this work is suggesting is that by 2050, compared to present, the demand for water will have increased by X% and the sustainable supply will have dropped by Y%; there will not be enough water to meet demand. There are, however, plans to commission two further seawater desalination plants, of a similar capacity to the Spring Garden Plant.
Even if we add these two into the supply, there would still not be enough water available. It is also obvious from this simple illustration that the losses of water from the system have to be addressed as a matter of urgency. By how much the losses can economically be reduced is a matter for discussion and has to be weighed up against other adaptation and policy options. We will consider the options available and the implications in a further piece.
Of course, as with all studies of this nature, there are assumptions and simplifications that are necessarily made and, the results are only as good as the data on which they are based. However, the results presented here are in-line with earlier work. Not only that, our recent experience of drought conditions provides us with a foretaste of what we might expect in the future. Furthermore, the magnitude of the difference between the calculated demand and sustainable supply is such that even accounting for uncertainties, it serves as wake up call to us all.
It should bring home the urgency with which we need to develop and implement adaptation options that are resilient to climate change and climate variability. If we don’t, then the people and the economy will suffer.
(Adrian Cashman CEng, PhD, MCIWEM is Senior Lecturer in Water Resources Management and Director of the Centre for Resource Management and Environmental Studies based at the University of the West Indies, Cave Hill Campus)