Islands of Sand

Animation showing the creation of islands in Dubai between 2001 & 2009 using Landsat images. Data courtesy of NASA.

This week we’re focusing on the development of Dubai’s land-coast interface between July 2001 and October 2009, looking specifically at the creation of the Palm islands and the World Archipelago. Dubai is the most populous city in the United Arab Emirates, home to 2.7 million people as of January 2017. In a place where Dubai police vehicles include a Lamborghini and a Ferrari, and where it’s possible to buy gold bars from vending machines perhaps it’s not surprising to see the creation of extravagant islands.

Palm Islands & The World Archipelago

In the animation at the top of the blog, the development of the Palm Islands and The World Archipelago are clearly visible. The first island created was Palm Jumeirah, the smallest of the three planned palm islands, and can be seen just off centre on the animation. It consists of a tree trunk, a crown with seventeen fronds and a surrounding crescent, and is approximately 25 square kilometres in size. Construction began in 2001 and was completed in 2006. The workers used GPS signals to determine the correct place to deposit sand to create the palm effect.

Built in tandem were the Palm Jebel Ali and The World Archipelago. Construction began in 2002 and was expected to be completed in 2015, however work stopped in 2008 due to the financial crisis. Work has remained suspended on Palm Jebel Ali, but development on the World may be about to start. The World has three hundred islands reclaimed from the sea, but most of them are bare sand. In the last twelve months there have been rumours that ‘The Heart of Europe’ project and floating seahorses around St Petersburg island could be developed in the near future.

It is also possible to see the preliminary creation of Palm Deira at the top of the animation. 300 million cubic metres of sand were used to form the initial reclamation. However, between 2009 and 2016 there has been no further development.

Images of Dubai in 2001, left, and 2009 taken by Landsat 7. Data courtesy of NASA.

It is also worth noting the significant urban sprawl between the first and last images. Dubai’s population increased by 95%, from 910,336 to 1,770,978, during the period we’re looking at and whilst the growth of Dubai is obvious, it is particularly visible southeast of the Palm Jumeirah development.

Creating the Time Series Animation

The animation was created using the first (blue) visible band of the Landsat 7 Enhanced Thematic Mapper Plus (ETM+) instrument. In May 2003, the scan line corrector – used to compensate for forward motion of the spacecraft, ensuring scan lines are parallel – failed. Consequently, the instrument images in a zigzag fashion; some data is captured twice, whilst some is not captured at all. As a result, 22 % of data in Landsat 7 images post May 2003 are missing. To compensate for this we’ve used a Geospatial Data Abstraction Library (GDAL) tool to fill “no data” regions by interpolating from nearby valid pixels. The results, whilst not perfect, are nearly indistinguishable at this resolution.

Impacts of the Islands

The development of these islands has not been without its criticism as it has impacted the local ecology. The dredging of sand has increased the turbidity of the seawater, with sediment transport evident in the animation, which has damaged coral reefs. In addition, water around parts of the islands can remain almost stationary for weeks, increasing the risk of algal blooms. Whilst fish have returned to these waters, they are not the same species as were there before.

Viewed from space, both the speed and scale of the development is mesmerising. It is no surprise that tourism is a vitally important part of the local economy, attracting more than 13 million visitors in 2014. With the limitations of available land in Dubai, developments are sure to start again.

 

Blog produced by Tom Jones on work placement with Pixalytics Ltd.

Our Beaches Are Shrinking!

Do you remember the fun of building sandcastles at the beach? It’s something almost every child loves to do, but perhaps not for too much longer. According to an article published in The New York Times last week, seventy-five to ninety percent of the world’s natural sand beaches are shrinking. According to Professor Gillis of Rutgers University, this is due to a combination of increased storm activity, rising sea levels and human development of the shoreline.

Landsat 8 Image of Chesapeake Bay from the 28th February 2014. Image courtesy of the U.S. Geological Survey.

Landsat 8 Image of Chesapeake Bay from the 28th February 2014.
Image courtesy of the U.S. Geological Survey.

The impact of storms was demonstrated last winter when millions of tonnes of sand were stripped from our shores. The beach at Formby in Liverpool lost thirteen metres of coastline, whilst in Cornwall Perranporth lost about a million tonnes of sand, Fistral Beach in Newquay lost thousands of tonnes of sand and the beach at Bude almost disappeared completely.

A snapshot of sediment movement can be seen in the Landsat 8 image above of the mouth of Chesapeake Bay in Maryland, USA. The Chesapeake Bay Bridge–Tunnel can be clearly seen stretching to the north, with a number of boats passing through it. The image is displayed as a pseudo-true colour composite, combining the red, green and blue wavelengths with some enhancements to bring out specific features. The suspended sediment around the coast can be seen in the complex colour patterns of turbulence and movement, and during storms this sediment will include the larger, and heavier, sand particles.

However, anyone who visited the seaside this summer might not have noticed the major loss of sand from last year’s storms. This is because beach replenishment is a major activity in many areas, either because the beach forms part of the protective barriers for the land or because the beach is tourist attraction. Sand is not an infinite resource, and most replenishment comes from other beaches, dredging or mining. For example, this year areas around Bridport and Lyme Regis in Dorset were reshaped with sand recovered from harbour dredging.

Beach replenishment is not the only usage of sand. Sand is the most consumed natural resource on earth, and the biggest user is the construction industry in the production of concrete. However, it is also used in any process that requires silicon dioxide which includes everything from wine to toothpaste, glass and computer microprocessor chips. In fact, according to The New York Times, the US sand and gravel business is fastest growing sector in their economy.

Sand is becoming scarce in the world. We need to start taking care of our sand, and think carefully about how we use it. Should we replenish every beach that loses its sand? If we don’t do start to take shrinking sand seriously, future generations of children may never experience the joy of building sandcastles on a beach.