Water: a warning or a threat?
From Vesuvio to Cotopaxi, 3 crossing points to survival
Who does not like Robert Harris, the novelist? In his 2003 novel Pompeii, he tells the story of Marcus Attilius Primus, who arrives in the Bay of Naples from Rome to take charge Aqua Augusta, the aqueduct that supplies water to the many towns in a region encompassing the Bay of Naples and Mount Vesuvius. Springs were failing for the ﬁrst time in generations. With aid from Pliny the Elder, a famous naturalist and natural philosopher, Attilius assembled an expedition to travel to Pompeii, the closest town still being supplied with water, and then on to the blocked section of the Aqua Augusta, to look into the problem.
The problem in the water supply system, as we discover, was caused by the accelerating eruption process of Mount Vesuvio, a stratovolcano laying the Gulf of Naples, about 9 km east of the beautiful city of Naples.
Unfortunately, Harris has this amazing ability to use real facts to build credible historical fiction. In fact, as we know well, the eruption of Mount Vesuvio was no joke, and the only hints of an eruption came a few days before the event, when the underground water sources ran dry and a minor earthquake occurred. Also, Pliny the Elder really existed. According to his nephew’s report, he died on Aug. 24, 79 AD, in an attempt to learn of an unusual cloud formation, later found to have resulted from the eruption of Mt. Vesuvius.
Underground water flow was the only sign, the only hint, the only warning. Run. Go away. Water was a friend that no one listened to. KaBOOM.
2015. I wake up at 5AM. At about 5:35AM, on any clear day on my way to work from Cumbaya to Quito I see a beautiful mountain: Cotopaxi. Besides looking like an amazing symmetrical upside down gelato-cone, Cotopaxi is also an active volcano, located about 50 km south of Quito.
In April 2015, the volcano began to show signs of unrest and came back to life. There was a large increase in earthquakes and SO2 emissions. On August 14 and 15, an ash and steam eruption occurred.
79 AD. Vesuvio. Water. A warning.
2015 AD. Cotopaxi. Water. A threat.
The production process of potable water in the Metropolitan District of Quito starts from the springs and slopes from which the Empresa Publica Metropolitana de Agua y Saneamiento de Quito (EPMAPS) gets its water. There are four systems:
La Mica – Quito Sur, which captures the waters coming from the Volcán Antisana, with a capacity of about 1,650 liter per second;
El Sistema Conducciones Occidentales, which captures the waters from the sub-systems of Atacazo, Lloa and Pichincha, with a capacity of about 700 liter per second;
El Sistema Papallacta Integrado, which captures the waters from the Antisana reserve, with a capacity of about 3,000 liter per second;
El Sistema Conducciones Orientales, which captures the waters from río Pita, with a capacity of about 3,000 liter per second.
Why would water be a threat? Well, it would be a threat for these systems from the Cotopaxi itself … The main problem relies in the destructive force of the lahar, a hot or cold mixture of water (with glacial ice and snow) and rock fragments flowing down the slopes of a volcano and river valleys. When moving, a lahar looks like a mass of wet concrete that carries rock debris ranging in size from clay to boulders more than 10 meters in diameter. Depending on the slope characteristics, it can reach a speed up to 100 kilometers per hour and flow distances of more than 300 kilometers, causing absolute destruction in its path.
Now imagine: the Cotopaxi glacier has an estimated volume of 1.0 km3. Its snow and ice fields cover approximately 20 km2. In case of an eruption, catastrophic lahares could potentially spring and flow down river valleys, which would become natural drainage canals.
EPMAPS’s water distribution system passes under river valleys in 3 points:
In the San Pedro river, with waters belonging to the Papallacta system
In the Pita and Santa Clara rivers, with waters belonging to the Mica Sur System.
Three key crossing points that are at risk. They are so important: in the most pessimistic scenario, lahares flowing down the Pita and Santa Clara rivers would break the distribution pipes and interrupt the water flow from the Pita and La Mica systems. Additionally, the syphon that crosses the San Pedro River would be damaged, breaking a precious connection in the distribution system of the Papallacta system.
This scenario would represent a loss in the water volume for EPMAPS water supply of about 80%. Just for three crossing points that at the moment are key for the whole distribution system.
EPMAPS is taking extra-ordinary measures to deal with the situation and the Quito Municipality and the Central Government are acting fast.
The clock is ticking…Will we make it? Men against volcanoes. Again.
Water. We need your help again. A hint. A warning.
See also previous blog on water as life and destruction: http://blogs.iadb.org/agua/2014/01/26/entre-vida-y-destruccion/