A modular water transport system
Urbanisation, irrigation and changing rainfall have left the Mediterranean area short of fresh water. In particular, countries like Greece are struggling to cope with massive seasonal demand for water created by millions of tourists in the dry summer months. The EU-funded XXL-REFRESH (Bringing a modular technology for fresh water sea-transportation to full scale) initiative has developed an innovative and affordable way to transport large quantities of fresh water from water-rich to water-poor areas by sea using modular flexible barges. To do this, researchers improved the design of 'waterbags', flexible plastic containers developed during a previous EU-funded project. Their main goals were to scale up the original concept to commercial size and to reduce drag created when the waterbags are pulled by tugboat. Their new design introduces two key modifications to the waterbags. They used open modular textile containers connected by extra-strong watertight zips, and an online monitoring system to control container deformations during transport by sea. The zipper makes it easy to customise the size of the waterbag simply by adding or removing individual segments. Fibre-optic sensors attached to the bags' fabric monitor stress and deformation, allowing the captain to adjust the tugboat's speed to prevent the zips from bursting. To check whether their new design would work at a commercial scale, XXL-REFRESH transported 2 000 cubic metres of water at sea in a 60 m-long prototype. Having found that the waterbag worked as predicted, researchers compared its techno-economic performance against alternative methods used to transport water. Their assessment suggests that XXL-REFRESH's waterbags can deliver the same service as currently used tankers and pipelines, at lower cost and with less environmental impact. Unlike tankers and pipes, the waterbag can be unzipped and stored flat. XXL-REFRESH will help small and medium-sized communities ensure a regular supply of water, particularly during times of high demand. This technology can also be used to provide water as part of an emergency response to drought or other natural disasters.
Keywords
Water transport, Mediterranean, fresh water, XXL-REFRESH, waterbags