Pamukkale: Cotton Castle

The travertine terraces of Turkey’s Pamukkale (translates to Cotton Castle) take a fair amount of work to keep them pearly white. In the past they were mistreated – a hotel was built overlooking the site with access roads cutting through it and people were free to scramble over and bathe in the pools (check out the postcards from yesteryear). It’s now been realised that this practice is not sustainable and guards are continually chirping their whistles to keep tourists from taking that extra step. Like the Mammoth Hot Springs of the USA and Huanglong of China, as water surfaces from underground thermal springs, carbon dioxide degasses from it, and calcium carbonate is deposited. Initially the deposit is a soft jelly, but this eventually hardens into travertine. Temporary diversion of the mineral spring flow gives an opportunity for the sun to bleach the natural pools and tourists to cover themselves with mud in the synthetic pools (win-win!).

The SPICE Project

Seeing these photographs side-by-side reminded me of Dr Hugh Hunt’s SPICE (Stratospheric Particle Injection for Climate Engineering) Project.

The SPICE project investigates the benefits, risks, costs and feasibility of solar radiation management through the deployment of reflective aerosols in the stratosphere. We propose that particles can be delivered to the stratosphere through a high-pressure pipe suspended by a balloon tethered at an altitude of 20 km. An ultra-high pressure pumping system would deliver a particulate slurry to be dispersed at altitude. The resulting particulate cloud would then lead to global cooling by increasing the albedo of the planet in just the same way as the planet cools after a large volcanic eruption. The project falls under the general heading of “Geoengineering”, ie how to cool the planet if we fail to control global CO2 emissions. SPICE presents many novel engineering challenges, especially the design of the pipe and pumping systems to withstand pressures up to 4000 bar and tensions up to 500 tonnes. Source: Monash Univeristy

Marina Barrage: Reservoir in the City

On researching a few facts about the engineering marvel that is the Marina Barrage, I learned that the Singapore International Water Week was recently held, attracting 10,000 attendees from over 85 countries/regions. From my own country, Tom Mollenkopf from the Australian Water Association presented on Meeting Australia’s Water Infrastructure Needs and Ross Young from the Water Services Association of Australia presented on Current Water Challenges, Drivers for Reform and Up and Coming Infrastructure Projects.

Mainly focussing on desalination projects around Australia, Young concluded his presentation by stating that the impacts of climate change are driving unprecedented capital expenditure programs and that despite the challenges the Australian urban water industry is in good shape to address them. One such project is the highly contentious Wonthaggi desalination plant which is something I’ve taken a bit of an interest in due to its proximity to home. I think it is quite clear that if it rained more, there would be no argument.

Unlike southern Australia, it actually rains in Singapore. And oddly enough, they too face the same challenges in meeting the needs of their people in securing potable water. Given the size of the country (~710 sq. km and expanding due to land reclamation) they have had to become creative in building reservoirs.

Built across the mouth of the Marina Channel, the Marina Barrage creates Singapore’s 15th reservoir, and the first in the heart of the city. With a catchment area of 10,000 hectares, or one-sixth the size of Singapore, the Marina catchment is the island’s largest and most urbanised catchment. Together with two other new reservoirs, the Marina Reservoir will increase Singapore’s water catchment from half to two-third’s of the country’s land area. Source

With 405 solar panels supplementing the daytime power requirements of the Marina Barrage facility, the Sustainable Singapore Gallery housed within is an excellent means by which to educate the visiting public on the significant environmental and water issues the world is currently facing. There is also an interesting scale model of the barrage which simulates rain, tides and the synchronisation of the crest gates with the drainage pumps.

Acting secondly as a tidal barrier to alleviate flooding in the city, if it rains heavily during low tide, the crest gates of the Marina Barrage will be lowered to release excess water from the reservoir into the sea. If, however, it rains heavily during high tide, then the crest gates will remain closed and the giant drainage pumps will be activated to move excess water into the sea.