site.btaDay 92: Assoc. Prof. Tzankov Says Bulgarian Antarctic Base Can Have Gravity-fed Water Supply from Nearby Glacier
Three main water sources were surveyed during the 31st Bulgarian Antarctic Expedition, from which water could be drawn to supply the building complex of the Bulgarian base "St. Kliment Ohridski" on Livingston Island, Assoc. Prof. Boris Tzankov, Vice-Rector for Development and Information Technology at the University of Architecture, Civil Engineering and Geodesy and lecturer at the Department of Hydraulics and Hydrology, told BTA in an interview. Tsankov is a participant in the Bulgarian Antarctic expedition as a specialist in hydraulic facilities. An uninterrupted water supply at the base, which is currently lacking, is one of the priority goals for the Bulgarian Antarctic mission.
"We intend to supply the current buildings and the newly constructed laboratory complex from an existing water supply that draws water from the nearby glacier via a siphon line. The route will take the water to a reservoir on the laboratory complex site, located at a lower elevation than the water level of the current water intake. This means the water can be gravity-fed to the laboratory," explained Tzankov, adding that water will flow into the base round the clock, which will also provide protection from freezing. If some of the water in the tank overflows, it will drain into the ocean, he said.
As an emergency supply, water is to be pumped from a storage facility with a weir to the new reservoir and from there water will be gravity-fed back down to the building stock. Separately, it is planned that each of the buildings will have its own reservoir with a capacity of about 5-6 cubic metres so that water can be provided to the complex when temperatures fall below freezing and the water supply freezes. A reservoir of about 30 cubic metres is envisaged for the new laboratory and, adding this to the remaining 15-20 cubic metres, in the event of a freeze the complex will have a water supply sufficient for about a week to ten days to ensure normal life and work at St. Kliment Ohridski", said Tzankov.
"Since we cannot predict the life of the water sources - how sustainable they will be in time, for now we see only the Todorini Buzi Lake as sustainable. From there we will transfer water as a filling derivation to the lower facilities, but this will happen at a later stage - in the next 2-3 years," he noted.
"There is another option of water extraction, but it is still subject to study - the desalination of ocean water. In such a case, a borehole would be drilled on the shore and fed by drained ocean water, which would be transferred to a facility for reverse osmosis and subsequent desalination," Tzankov explained.
The challenge to building a water supply system is the uneven terrain around the Bulgarian base. "We have to route the terrain. It would be difficult to design a route on a map and to situate it on a map. The laying is superficial - by studs and brackets on the terrain, which is made up of fractured rock and stones of different types and sizes. The studs are difficult to drive into places - it has to be ascertained by trial and error where the relevant support will fit firmly into the terrain. Unstable ground mass must also be avoided, for example tracing through glaciers as they move. This is why tracing can only be done in the field," the specialist explained.
As part of the 31st expedition, a 100-metre-long pipeline was also laid on an experimental basis to check the condition of the route after the Antarctic winter, and how winds and snow drifts affect the route. "On the next expedition, we are resuming work with the laying of new polyethylene pipes to the existing building stock on the base and running a route to the future tank of the laboratory complex under construction," added Tzankov.
BTA's Daily News editor Konstantin Karagyozov is the only member of the media who is travelling on board the ship to Livingston Island and back and covered the Bulgarian expedition on site throughout its stay in Antarctica.
All media outlets can use the Bulgaria-Antarctica BTA's Log for free.