Water Pipelines in Arid Regions: The Arteries of Industry
As reserves of clean, fresh water rapidly diminish, global water supply is an increasingly fundamental concern. Arid areas in particular either require water to be transported long distances or rely on costly desalination plants. With this in mind, Rowan Watt-Pringle investigates the challenges and rewards involved in piping water into arid locations.
According to the Fraunhofer Society, Europe's largest application-oriented research organisation, more than a billion people worldwide do not have access to clean drinking water, despite the UN General Assembly's recent resolution that this is a basic human right.
The German research institute also highlights the fact that water is fast becoming the most important resource on the planet and will soon be of more strategic importance than petroleum: on top of people's basic need for drinking water, "water is a pre-eminent economic factor because agriculture and industry consume more than four fifths of this precious commodity". This is even more pertinent in arid regions, where access to clean fresh water is limited at best.
The UAE: oasis in the desert
In February 2011, Lindenberg-Emirates will complete the construction of a major water supply pipeline to a group of islands off Abu Dhabi, opening the area up to industrial and residential expansion.
Dubai Electricity and Water Authority (DEWA) CEO Saeed Mohammed Al Tayer told members of the press that the pipeline was part of DEWA's flexible strategic plan to combat rising demand for its services, citing the fact that demand for water in Abu Dhabi increased by 5.9% in 2010 compared with 2009.
The islands under development – Saadiyat, Jubail, Al Fahid and Yas – will be able to receive approximately 76 million gallons of water a day from the DEWA subsidiary, Abu Dhabi Transmission & Dispatch Company (TRANSCO), which originally awarded the construction contract to Lindenberg in January 2008.
Reports from Lindenberg highlight the fact that the pipeline is the first phase of a world-class development infrastructure spanning investment opportunities in residential, business, cultural and leisure sectors. Lying just 500m off the coast of Abu Dhabi, Saadiyat Island alone represents a planned $27bn development scheduled for completion in 2018; without the pipeline the entire venture would effectively be dead in the water.
Bridging the gap
The pipeline project, which will eventually cost a total of $157m, has to cross the four sea channels to link the group of islands to the mainland and highlights many of the challenges and rewards involved in constructing water pipelines.
The 1,600m stretch of 48in-diameter carbon steel pipes between Jubail and Al Fahid islands – completed in May 2010 – lies 25m below the seabed and required the use of the highly advanced technique of horizontal directional drilling (HDD). This section of the pipeline represents the longest submarine HDD crossing in the world.
A number of other processes need to be considered in the laying of submarine cables, such as impressed current cathodic protection (ICCP), which uses anodes connected to a DC power source to prevent saltwater corrosion of the carbon steel pipes.
Telecommunications and instrumentation works include the laying of fibre optic cables for both onshore and submarine pipelines, with the latter placed alongside the pipeline in HDPE heavy-duty pipes via bi-directional drilling.
Freshwater pipeline to quench Chile's thirst
Chile, meanwhile, is planning a $3.85bn freshwater pipeline to stimulate social and economic development in the country's arid northern region, according to reports from United Press International (UPI) in November 2010.
The project – planned for three construction phases over the next five years – will include roughly 600 miles of subsea pipeline.
Technology transfer foundation Fundacion Chile, along with the Chilean branch of French construction giant Vinci, believes that major industrial consumers will be integral to the success of the project and hope that they can persuade key consumers to switch to freshwater, thereby saving the energy required for the desalination process.
UPI quotes experts' claims that transporting water from the south will be more economical than desalination in the north, with desalination in Chile costing $1/m³ of water, compared with $0.49/m³ of piped freshwater.
One potential challenge is the relative frequency of earthquake tremors off Chile's coast, however the project continues nonetheless, with the country's former Public Works Minister Eduardo Bitran offering his backing to the pipeline by saying, "Never has water been so scarce, so transporting it is good business ... [it] is the gold of the future."
In order to combat the earthquake threat, UPI says that the pipeline will be secured to the seabed at varying distances from the coastline and will be built "using a proprietary technology – submariver – that provides greater resistance to rocks and to internal and external pressure changes".
Fraunhofer Alliance SysWasser
The Fraunhofer Society comprises 80 research units throughout Germany, including 59 Fraunhofer institutes. 14 of these institutes have banded together to form the Fraunhofer Alliance SysWasser to research sustainable water system technologies.
At the IFAT / Entsorga fair held in Munich in September, the alliance unveiled several technologies to meet challenges faced by water pipelines and other water systems.
The HydroDyn management solution, which is already in use in arid regions such as Mongolia, Libya and Saudi Arabia, was developed with drinking water suppliers to calculate the optimum operating regime for drinking water supply systems, plan system expansions and automatically localise leaks.
Another innovation comes in the form of "intelligent" probes that check pipelines from the inside to pinpoint damage, while long-distance ultrasound waves can also find cracks or pipe corrosion – particularly valuable in arid regions where the detrimental effect of lost water is magnified.