IMPACT OF CONSTRUCTION OF PALM JUMEIRAH ON THE NATURAL ECOSYSTEM
CRP 8420
Introduction to Dubai
- one of the 7 Emirates in UAE & contributes 41 miles to the UAE coastline
- Dubai's booming economy was built on oil reserves that were discovered in the mid 1960's
- It has worked hard to improve the tourism by constructing world's richest horse track, several multi-storey hotels and technological innovations to rule the nature
Introduction
Limited Oil reserves
- projections that the Oil reserves will get depleted by the end of this decade
- early dependence of GDP on oil based sector was more than 70%
- Dubai began to cut down this to 10% by 1990's
- presently the oil based sector contributes less than 1% to GDP
- Tourism contributes almost 20%
- Dubai is an international IT hub that serves service industries such as Finance and IT.
- Dubai Internet City, along with Dubai Media City forms the TECOM (Dubai Technology, Electronic Commerce and Media Free Zone Authority), which is an enclave who houses well-known IT firms such as Microsoft, , Dell, Oracle Corporation and IBM, and media organisations such as BBC, MBC, CNN, Reuters and Sky News (Bagaeen, 2006).
Decrease the dependence on oil reserves
Tourism on boost
- Tourism infrastructure to accomodate more than 15 million in Dubai (2016)
- Tourism contributes to more than 20% of GDP of Dubai and 66% contribution of GDP of UAE
- Dubai now boast of highest revenue by any city per room (US $175.47, Dept. of Tourism) more than New York and Paris (Higgins, 2013).
- Several celebrities and politicians own properties like Andre Agassi, Serena Williams, President Trump
Tourism rise
Proposed development on similar lines
Satellite Image of the Persian Gulf, off the coast of UAE
PALM JEBEL ALI
Palm Jebel Ali
- another artificial archipelago in list of Palm Islands
- will house 250,000 people by 2021
- development will be 8 times than Palm Jumeirah
- project will include 6 marinas, water theme park, Sea village: homes built on stilts
- includes the broadwalks that circle the fronds and spell out an Arabic poem by Sheikh Mohd. bin Rashid Al Maktoum
Image source: (Salahuddin, 2006)
PALM DEIRA
- Largest of the 3 Palm Islands
- After construction will cover an area greater than the city of Paris!!!
- Featuring 8,000 two-storey houses, villas, and town homes, it is a thriving city in itself.
- This unique man-made palm-shaped island will consist of a trunk, a crown with 41 fronds, and a surrounding crescent island that will form a water breaker.
Image source: (Salahuddin, 2006)
Palm Deira
THE WORLD ISLANDS
The World
- roughly in the shape of World map
- consists of 300 island off 2.5 miles from Dubai coast into shallow waters of the Persian Gulf
- The island in the shape of Lebanon sold at $22 million with complete developement
- Islands in the project range from 150,000 to 450,000 sq ft in area.
- The World's overall development costs were estimated at $13 billion CAD in 2005.
- Roughly 144 mi of shoreline was created.
Image source: (Salahuddin, 2006)
The construction begins.....
- by late 1990's entire Dubai coastline covered with hotel thus making the present ruler H.H Sheikh Muhammed Bin Rashid Al Maktoum engage to build new coastlines artificially
- shape of palm tree to maximize the beachfront
- Govt. controlled Nakheel assigned the task who engineered it by Belgian (Jan de Nul) and Dutch (Van Oord) dredging and marine contracting firms
Construction
Intensity of the Palm Jumeirah construction
Dubai's coastal geography and climate
- location at the south-east end of the Persian Gulf, on the west coast of (UAE).
- with a semi-enclosed marginal sea, the Gulf nearby has an average depth of 50 m with a maximum depth of 90 m.
Image source: (Lavieren et al. 2011)
Geography of Dubai
Temperature and Salinity Content
- evaporative sea surrounded by completely dry land masses
- summer temperatures soaring as high as 122 degree Fahrenheit
- high evaporation rates causes increased salinity as high as 41.5 gm salt/kg of water
- thus the natural habitat in this area is adapted to high temperatures and high salinity conditions
SHAMALS
- Gulf region experiences periodic storms known as Shamals from December to January and May to June coming out of the north/north-west and which are often laden with dust and sand.
- strength of shamal winds has been measured up to 78 kph though the average wind speed is 48 kph
- being the principal force behind wave action in the Persian Gulf, shamals produce average wave heights of 1 m to 2 m and typically last one to three days.
- the subsequent currents (called Shamal currents) have pushed sunken barges and planes around, on the bottom of the Gulf near Dubai
Periodic wind storms
Arabian Gulf is also characterized by shallow waters. Its depth ranges from about 35 meters on the Arabian side to about 81 meters on the Persian side. Also, the slopes leading into the basin are low and shallow; hence the waters of Dubai are shallow enough to allow land reclamation.
Dubai's coastal slope
Main features of Palm Jumeirah
(Gibling (2013), Higgins (2013), Rutz (2012)).
BREAKWATER FEATURES
Breakwater Construction
- primary protective barrier against shamals and stong waves in a crescent shape
- contains two 100 m gaps or openings at 3' o clock and 9' o clock to allow tidal flushing and complete water circulation within 13 days once
- 11 km long and 200 m wide and can withstand waves up to 5.2 meters high.
- Its triangular shape allows it to slow waves and force them to break at a distance 15-20 meters away from the main structure.
- At 5.2 meters above mean sea level, the breakwater extends 1.7 meters above the height of the highest waves ever recoded in the area.
- Atop the breakwater is a 1.2-meter-high wall to further protect the development. Next to the wall lies a road that is 36 meters wide, providing a buffer against any unpredictably violent storms that might rarely occur in a centuary
FRONDS FEATURES
- Desert sand being too fine, was replaced with an ideal supply of sand, 6 nautical miles from the site which was coarse enough to be packed densely
- GPS technology was used to check the linearity of constructed fronds
- A total of 70 million cubic meters of sand was used in the construction of the fronds.
- The trunk section was about 5 km long and 457 meters wide while each of the 16 palms were about 5 km long.
Fronds Construction
Safety features enabled in Palm Jumeirah
Additional features
- able to withstand to 1 m sea level rise
- able to withstand earthquake up to 6.0 on Richter scale
- estimated rate of subsidence is 5 mm/ year
Construction features
Flawed estimation of the construction density
Plans for Palm Jumeirah originally projected 1400 villas and 2500 apartments.
By 2005, those doing the maths had arrived at a far denser figure of 8000 domiciles and is still rising.
Source: http://www.keoic.com/Projects/Details/1248
Density on the 'breakwater'
Mass mortality of the marine organisms
Impacts on the marine life
- Construction caused sediment flow away from the island and the absence of cloth silt screens enabled them to clog the nutritive openings of the marine organisms
- Dimensions of Palm cause sediment to transport to almost 3 times its own area
- Nakheel's assumption that the breakwater will provide for a new habitat to the corals and marine life is not based on logical testing results (Salahuddin, 2006).
Mass mortality of coral reefs
- The Palm construction would bury almost 0.83 to 1.25 sq.km of coral beds under it, roughly a million sq. m of 'coral foundation bed'
- sand leakage from dredgers, transporters and cascading off will cause suffocation to the coral in construction debris. This debris would kill an additional 2,500,000 sq.m of coral.
- dead coral generated by Palm Jumeirah's construction will have a longer length that Palm itself when placed in the line
Impact on coral reefs
Source: (Lavieren et al. 2011).
- Extensive dredging of sand from offshore areas necessary for construction have impacted the sea grass beds on a large scale
- sediment starvation have damaged the positive effects the mangroves play in the coastal ecosystem
Impacts on sea grass beds and mangroves
- Dissolved oxygen concentrations varied seasonally within the lagoon, remaining ~10% lower than at reference sites, but stayed consistently above the 3.2 mg/L minimum critical for fish survival.
- Nitrate levels (plus nitrite) were higher than expected (~5 microM). Levels were not depressed during periods of high phytoplankton growth, suggesting abiotic replacement of N from the sediments.
- Marine larvae cannot settle on the bottom of the gulf due to loose CaCO3 sediment forcing it to reside in the breakwater areas facing constant disturbances by anthropogenic activities (Cavalcante et al. 2012).
Impact on other organisms
Degradation of natural coastline of Dubai
- sediment starvation is expected downstream
- long shore current will be forced around the structure and thus causing increased velocity and scour
- the beaches to the east of the Palm are worst affected since the primary direction of the sediment transport is the eastward
- Dubai municipality estimates loss of 10,000 to 15,000 cu. m of sand annually
- 3 Palm Islands are expected to make the shoreline starve up to a distance of 40 km out of 65 km total distance.
- Tidal in-working are also altering the size of fronds
- Lack of visibility due to sediments, down from 20 to 5 m creating a problem for divers in the region (Salahuddin, 2006).
Impact on natural coastlines
Continuous re-nourishment
- recent replenishment of 7 beaches along 8 km coastline required around 3,500,000 cu. m sand causing beach extension of 30 m.
- Breakwaters contain around 540 tons of hard rock that prevent the sediment transport
- employment of sand bags
Dubai's efforts to prevent coastal erosion
- The mean residence time of water within Palm Jumeirah after 15 days.
- This image shows that
(1) flushing is less efficient inside the fronds close to the stem, especially on the west side where water exchange is still only about 50% after 2 weeks and
(2) water becomes trapped between fronds which leads to residence times > 2 weeks.
- Both indicate a potential for water quality problems.
Irregular flushing time
Source: (Cavalcante et al. 2012).
Construction of artificial reefs
- Nakheel plans to construct dive sites to resemble the reef structures all over the world as Bali, Great Barrier Reef, Cayman Islands, Red Sea
- Artificial reefs are combatible to Shamals
- create provision for coral larvae to settle upon and larger corals to be grafted into it
- Installation of silt nets to catch the flowing sediment
Steps taken to mitigate the impacts
Artificial Runde Reef
- concrete core measuring 2.5 m in height, from which the core sprout scores of recycled, polyethylene tubes radiate in all directions expanding the structure’s diameter to 5 m.
- This 8-ton reef generates 250 sq. m of outer surface area and 340 sq.m of cavity space for marine flora and fauna to colonize
- installation of 3 Runde Reefs about 400 m beyond the center of The Palm Jumeirah’s breakwater to attract coral, algae, fish and shellfish
- After 2 months, divers observed algae and one fish at the Runde Reefs.
- After 4 months, divers observed soft coral polyps, mollusks, and 8 species of fish (Salahuddin, 2006).
Runde Reef Case Study
Images of developed ecosystem
After 2 months of installation
After 4 months of installation
Source: (Salahuddin, 2006)
- Dredge and fill procedures cause sedimentation and turbidity during and after periods of construction due to re-suspension of fine sediments.
- Pre-construction evaluation was inadequate
- specific design aspects of an island development can introduce significant physical and chemical challenges that may degrade habitat quality and prevent colonization by desired species of aquatic organisms.
- Breakwaters may provide alternative habitat for fish and benthic organisms.
Conclusion & References
References
- B. Salahuddin (2006) The Marine Environmental Impacts of Artificial Island Construction. Duke University, 2006
- Cavalcante, G.H., Kjerfve, B., Feary, D.A., 2012. Examining the residence time and its relevance to water quality within a coastal mega-structure: The Palm Jumeirah Lagoon. Journal of Hydrology 468-489 (2012) 111-119.
- Higgins, K. (2013). ‘Engineering Challenges of Palm Jumeirah’. PT-2013: Coastal and Ocean Engineering ENGI 8751
- Rutz, K. (2012). ‘Artificial Islands versus Natural Reefs: The Environmental Cost of Development in Dubai’, International Journal of Islamic Architecture 1: 2, pp. 243–267, doi: 10.1386/ijia.1.2.243_1
- Van Lavieren, H., J. Burt, D.A. Feary, G. Cavalcante, E. Marquis, L. Benedetti, C. Trick, B. Kjerfve, and P.F. Sale. 2011. Managing the growing impacts of development on fragile coastal and marine ecosystems: Lessons from the Gulf. A policy report, UNU-INWEH, Hamilton, ON, Canada.