Water Shortage in the Middle of the Ocean

A notable hardship facing many island nations, which I have alluded to previously, is a shortage of local freshwater. While more elevated islands and continents face this difficulty, such shortages are perhaps a more urgent concern for low-lying coral islands. After all, humans and many terrestrial organisms require a freshwater supply for long-term sustenance, and small islands tend to have less voluble (and more vulnerable) reserves of fresh groundwater. Like many other environmental concerns, this trend has been aggravated by a warming climate, especially rising sea levels. While I have previously explained the link between rising sea levels and the increasing fragility of water tables on low-lying islands, I will rehash it in more detail for the reader’s convenience. Most of the world’s lowest and flattest islands have coral foundations, formed from the accumulated fossil remains of dead coral. As this mineral structure is porous, the freshwater lense (i.e. the groundwater supply) of a coral island is easily penetrated by the salty sea water around the island, making it more brackish. A rising sea raises the level of saltwater infiltration, as well as the contact area between the ocean’s saltwater and the island’s freshwater, increasing the volume of saltwater which mixes with the latter. If my explanation seems a bit confusing, here is a visual diagram from the EPA website which illustrates the situation.

As can be seen, sufficient rainfall raises the freshwater lense above the level of saltwater penetration, providing a measure of potable groundwater. However, rain is by no means consistent between seasons, and droughts happen. Again, it is low coral-based islands which are most reliant on rain for their freshwater, and most vulnerable to seasonal or climatic changes, especially heavy storms or droughts. One such drought in 2011 affected the countries of Tuvalu and Tokelau, along with parts of other Pacific nations, as reported in The Guardian. The situation became so dire that both countries were forced to meet their needs with bottled water and desalination machines. On the main atolls of Tokelau, the freshwater supply was depleted, and locals were forced to survive on bottled water from Samoa. At one point, on one of the islands of Tuvalu, only 16 gallons (73 litres) of fresh water were left for 350 residents; even in the capital of Funafuti, water was rationed to two buckets per day. As would be expected, this also had a negative impact on health and hygiene. In Tuvalu, food supplies were diminished by the drought and saltwater, while government officials opted to bathe in the lagoon so as to save water. In Tokelau, schoolchildren were required to return home if they needed to use a toilet, and domestic tasks requiring water use were suspended. Most of us can only imagine facing such extreme circumstances. However, even in the crisis related above, it can be seen that humans are quite capable of adapting when an absolute need to do so arises. Speaking of which, I will take some time to briefly address the means of adaptation which have been employed by islanders in response to reduced freshwater availability. Two such means were mentioned already: the import of bottled water, and desalination machines. While imported water on its own is not a viable means of long-term sustenance, it does provide for short-term relief. Desalination, or the removal of salts from seawater via machine, is perhaps more viable as a long-term local supplement. Another common method used to cope in dry environments is the construction of catchment systems, that is, structures and features designed to collect and store rainwater. Evacuation, while remaining a possibility, is reserved as an absolute last resort. As I came to realize in my last post, true adaptability means being open to multiple possible solutions, rather than resigning to the worst case scenario.