Water resource in Galapagos
One would expect islands such as the Galapagos, located in Ecuador, were a lush tropical paradise with lush vegetation. However, this is not the case. The annual rainfall in the lower part of the islands is just about 60 to 100 mm, air temperature ranges between 21 and 29° C and that of the sea is very low.
This is the result of the influence of the deep Humboldt Current, which originates in the South Pacific and emerges in a region near the Galapagos Islands. This ocean current, of relatively cold water, produces temperature inversions that prevent rainfall and generate very dry areas where the land is closest to it, as on the coasts of Chile and Peru (where the Atacama Desert is located) and of course, in the Galapagos.
It is this water shortage that defines the unique ecosystems of the Galapagos, and determines the nature and behavior of their species. Giant tortoises, a symbol of the islands can withstand lack of water for a year.
Darwin’s finches wait for the rains before procreating. Palo Santo trees are without leaves during the drought. And sea lions take water from the fish they consume.
What about humans? With the exception of San Cristobal, the availability of natural water sources for agriculture and domestic use is almost nil. So how have the local people obtained this vital resource so far?
And in a rapidly developing human sector, how can you secure your supply, while conserving the integrity of the natural ecosystems and ensure the health of the population?
In the beginning…
Without doubt, it was the barren appearance and lack of water that lead Fray Tomas de Berlanga, who discovered the islands in 1535, to classify them as “hell”.
For many early visitors to the islands, it looked bleak, with an impassable terrain and lack of fresh water.
In the eighteenth century, the islands were the place for pirates and whalers to acquire fresh meat, firewood or water. The few places for fresh water they found following the footprints of giant tortoises.
In 1829, Charles Darwin, almost certainly, would not have decided to stay on the islands for long, had he not spotted from the Beagle, the only river visible on Galapagos that flows into the sea, in San Cristobal.
The first of the islands’ hydraulic works was built in 1869 in San Cristobal. Felipe Lastra, Manuel J. Cobos’ peon, owner of the island, developed a system of canals to carry water by gravity to the El Progreso hacienda and thus irrigate sugar cane plantations.
In the other populated islands (Santa Cruz, Isabela and Floreana) the principal occupation of the early settlers was to search for resources essential for survival.
They depended on rain or drank brackish water, except in Floreana where there were still small freshwater springs. According to a well-known saying of the time in Santa Cruz, such was the custom of tasting the salt in the water when the coffee was made with fresh water, “the settlers added salt!”
In 1942, while the best water source was in San Cristobal, the U.S. Air Force implemented a base in Baltra Island (north of Santa Cruz), due to the low, flat character of the island and especially its strategic location, where they could prevent an attack by the Japanese and monitor the Panama Canal. To carry the precious liquid to Baltra they used the same canals left by Felipe Lastra from the ditches of San Cristobal to El Progreso and then another pipeline to Puerto Baquerizo Moreno, where ocean barges sailed up to the air base pushed by a boat.
Today, efforts to collect and filter rainwater has given way to piped water that the islanders buy from small companies that use desalination plants, while non-potable water comes from different sources, depending on the island.
In Santa Cruz, brackish water (a mixture of rain water and seawater) located in crevices near the shore, is the main source of water for the town of Puerto Ayora. However, the growing demand for a rapidly increasing population is putting increasing pressure on this resource.
Furthermore, due to leakage after household use, the used water mixes with the same water in those crevices, creating a health risk for the population.
San Cristobal Island has a permanent and significant source of subterranean water in the upper regions – a true exception in Galapagos!
In Isabela water is extracted from wells and in Floreana from small springs.
This explains why in Santa Cruz the tap water is salty, unlike the other islands. For the agricultural zones up high, rainwater and tankers are used.
Since 2003, Heliborne geophysical surveys were made, in collaboration with the University Paris 6, the Charles Darwin Foundation, the INGALA and the municipalities of Santa Cruz and San Cristobal for the presence of subterranean resources and to understand the functioning of the hydrological cycle in Santa Cruz and San Cristobal. The survey results are contained in the doctoral thesis of Noémi D’Ozouville.
The work of the Directorate of the Galapagos National Park
The Directorate of the Galapagos National Park, considering current levels of population growth in the archipelago and worried about the problems of water shortages, which have occurred in recent years in urban and rural areas, considers a plan and control of the use of water resources a priority.
Good management of water resources is essential not only for human development, but to preserve the integrity of natural ecosystems.
Under stringent studies and monitoring of water quality, in collaboration with other institutions, local, national and international, the DGNP seeks to minimize the risk of contamination and waste of fresh water from the local population.
With the assistance of the Japan International Cooperation Agency (JICA), the National Directorate of Galapagos began in 2005 a project to know the status of water quality in the Santa Cruz Island and then from 2007 on the islands of Isabela and San Cristobal.
Today, there is continued quarterly monitoring at permanent sites established for sampling and clinical analysis.
To determine the contamination level, the Technical Standard on Environmental Quality and Wastewater Discharge of Water Resources 2003, developed under the aegis of the Environmental Management Act for the Prevention and Control of Environmental Pollution, which regulates activities that could be sources of contamination to water resources and currently governed in Ecuador, are used as a basis.
This standard establishes a large number of parameters (amount of oil and grease, fecal coliform bacteria, detergents, mercury, lead, hydrogen potential among others) to determine water quality, which essentially addresses the possible contaminants that can exist in the water, effected by human activities, which must be below the maximum permissible limit (MPL).
Water quality in populated areas
Santa Cruz Island
For water quality monitoring in the Santa Cruz Island, water samples are taken to monitor terrestrial and coastal sites for physical, chemical and biological analysis.
In the monitoring of terrestrial sites, most of the places where water is drawn for the town of Puerto Ayora (the INGALA Crevice) and the Bellavista and Santa Rosa parishes are free from contamination.
However, there was a high content of fecal coliform in the Grieta del Colegio San Francisco where 27% of the water for Puerto Ayora is drawn.
In the monitored coastal sites, the laboratory results are more worrisome. The results of oils and grease, and mercury were above the MPL in some of the sites monitored. High amounts of phenols and mercury were also detected. Most notable was the very high fecal coliform contamination found in Laguna de las Ninfas, a place used as a recreational site by locals, national and foreign tourists.
San Cristobal Island
The study cited indicates that there are no problems of water supply coverage in Puerto Baquerizo Moreno, and that 100% of the urban area is served by the distribution network and the suburban areas are supplied by tankers.
However, the results obtained in the laboratory for analysis of fecal coliform, for water in Puerto Baquerizo Moreno, does not meet the established parameters of quality established for human consumption.
Indeed, unlike the samples taken from the Municipal water treatment plant, which is the collection site where water arrives from Upper Island sources before being distributed to the population of the island, the water in some houses of Puerto Baquerizo are highly contaminated.
This demonstrates that there is no disinfection treatment and that instead of reducing the coliforms have increased, threatening the health of the population. The results also show very low levels of chlorine residual, to be of use as a disinfectant.
Water obtained for human consumption is derived from underground crevices. It is characterized as fresh on the surface, originating as rainfall that penetrates and discharges into the sea; at a few meters deep it is brackish and salty at a greater depth.
In the monitoring results; concentrations of nutrients such as nitrites and nitrates and the total value of phosphorus are not high, which allows us to determine that water from Isabela Island does not have an excessive amount of nutrients.
However, in samples taken in Manzanillo, where the Provincial Council draws water for distribution by tankers to the inhabitants of the upper and the urban area of the canton, and in samples taken directly from the tap in different houses in Puerto Villamil, analysis for fecal coliform was positive.
At other monitoring sites, such as in Poza Salinas, a visitor site of ecological importance, since it is the habitat of species endemic and native to the area, contamination parameters were not found.