RESILIENT CITIES 2011

Transcription

1 RESILIENT CITIES 2011 EKO ATLANTIC CITY PROJECT AS A CLIMATE CHANGE ADAPTATION STRATEGY Presentation by Prince Adesegun Oniru ( Honourable Commissioner, Lagos State Ministry of Waterfront Infrastructure Development)

2 SHORELINE PROTECTION PROJECT BAR BEACH VICTORIA ISLAND LAGOS Introduction and review of Engineering Works executed from June 2007

3 SHORELINE PROTECTION WORKS What was the condition of Bar Beach immediately prior to the award of the contract in December 2005?

4 Storm event 0ctober 31 st 2005 The storm destroyed large sections of the nearside carriageway of Ahmadu Bello Way Sand in excess of 400mm thick was deposited on both sides of the carriageway rendering it impassable for motor vehicles Sea water entered the compounds and ground floor of adjacent dwellings

5 Ocean surge floods the beach

6 Encroachment of sea water

7 Flooding of road

8 sand deposits on carriageway

9 Erosion of beach front (west)

10 Erosion of beach front (east)

11 What is the Extent of the Erosion? Studies have determined that: Between 8 14m of beach-front is eroded annually along Bar Beach 2,800m 3 (average) of sand eroded daily

12 Introduction and Brief History Bar Beach, once a popular and prestigious beachfront, was the a poor reflection of its former glory Severe coastal erosion has removed in excess of 2 km of beach front and at times the adjacent road; resulting in acute disruption to traffic flow and flooding of properties The erosion is a direct result of the construction of rock moles between ; to protect the harbour access The moles interrupted the natural Littoral Drift along the African West Coast which transports and deposits sand along the beaches of Western Nigeria Since the early 1950 s to date in excess of US$250 million expended in regular sand replenishment to restore the beach, without providing a permanent solution

13 Search for a Permanent Solution Developers Energyx submit a privately financed proposal for a permanent solution in April 2004 subject to concluding further technical and financial reviews Energyx proposal reviewed with other alternative proposals by a joint Lagos State & Federal Government commission on 1st September 2004 Review continues into 2005 Mr. President authorises Lagos State Government to implement an agreement with a Developer for a Permanent Solution in August 2005

14 The Engineering Works Commence 12 th December 2005 Lagos State Government awarded a Contract to Hitech Construction to perform Shoreline Protection Works. 1,000m length of the most severely eroded section of the beach to be protected.

15 Cross section of shoreline protection ROCK ( Kg) ROAD SAND ARTIFICIAL SLOP ARTIFICIAL SANDFILLING SAND NATURAL SLOP ROCK ( Kg) Drawing Title: SOO1 SCALE 1: 100 DATE 15/05 /06 DRAWN JIHAD KAMEL (S.M) CHECKED AD de BEST (P.M) LEGEND kg kg SAND XBLOC Project: Drawing Title: SHORELINE PROTECTION TYPICAL CROSS SECTION BAR BEACH PROJECT VICTORIA ISLAND Engineer HITECH CONSTRUCTION CO. LTD. 8th Floor,1682 Sanusi Fafunwa Street Victoria Island,Lagos (234) Fax: (234) STRUCTURAL CIVIL ROAD ENGINEERS

16 Summary of Construction Process Sand Replenishment Contour Sand to required profile Lay Geo-Textile matting to beach-front Place first Layer of Rock (10 60kg) 300mm thick Place second Layer of Rock ( kg) 700mm thick Place x-blocs Further compacted sand layer on beach-top Lay Geo-Textile matting to beach-top Place Layers of Rock on beach-top to rear of x-blocs Cast 150mm thick concrete bed on remaining beach-top Form roadside drain and beam

17 SHORELINE PROTECTION WORKS COMMENCEMENT OF WORK.

18 Turning of Sod Celebration 5 th February 2006 Governor s speech

19 Turning of sod celebration inspecting the yard based model

20 Delivery of first x-bloc mould

21 Placing concrete in x-bloc moulds

22 First casting concrete x-bloc s 20th January 2006

23 Aerial view of pre-cast yard

24 x-bloc storage area

25 Concrete x-bloc production A total of 5,000 x-blocs were cast for the project over a period of 6 months Making use of chemical additives to the concrete mix maximum use of the steel mould was achieved with 2 castings every 24 hours from each mould utilising 2 teams of operatives working in shifts Frequent tests were made to each batch of concrete and each x-bloc to insure adherence to specification and strength attainment before transfer to the stock area and final location

26 SHORELINE PROTECTION WORKS QUALITY CONTROL

27 Taking concrete samples for laboratory testing

28 Storing concrete test cubes

29 Concrete slump test prior to casting

30 Crushing test cubes to insure design compliance in compressive testing

31 Taking core samples for testing

32 Crushing core samples to determine tensile strength compliance

33 Site testing of concrete

34 Dial indicating test result

35 Testing compacted sand for moisture content and degree of compaction

36 Testing sand quality

37 SHORELINE PROTECTION WORKS SITE WORK

38 Delivery of sand to beach-front to replenish and widen beach

39 Compaction of sand with dozer roller and water-tanker

40 Surveyor establishing levels on beach-front and shoreline

41 Establishing final profile on beach-front

42 Jointing of geo-textile material in yard to form large sheets

43 Placing weights on matting to insure anchorage on sea-bed

44 Forming initial rock barrier to waves

45 Aerial view of rock barrier to waves

46 Placing geo-textile on sea bed

47 Timing is critical the sea is unforgiving

48 Placing geo-textile to slope

49 Stretching geo-textile up slope and over beach-top

50 Placing first rock layer to base

51 Placing first row of x-blocs

52 Placing rock to sloping face

53 Placing x-blocs to slope

54 View at toe of x-blocs

55 Completed section of beach-front showing interlocking of x-bloc s and 10m of rock extending seaward

56 Levelling sand to beach top

57 Laying geo-textile to beach top

58 Setting out steel forms for concrete slab on beach top

59 Compacting concrete with vibrator

60 Placing and levelling concrete in slab

61 Protecting concrete slab from rainfall

62 Trowelling surface of concrete

63 Treating concrete surface with curing agent

64 Placing final rock boulders

65 Placing pre-cast concrete beams

66 Finished beach top / walkway

67 SHORELINE PROTECTION WORKS VIEWS OF THE FINISHED STRUCTURE

68 Elevation ocean side

69 Elevation beach top

70 Elevation roadside

71 Aerial view 1

72 Aerial view 2

73 A TIMELY INTERVENTION The Shoreline Protection Project was awarded on 12 th December 2005 for completion on 12 th December 2006 Between 16 th -18 th November 2006 Bar Beach was subjected to the worst storm on record for the previous 10 years

74 THE POTENTIAL FOR A DEVASTATING FLOOD Sea levels were elevated 1.5m above the average for the time of year It was estimated that during the peak of the storm the length of the structure was bombarded by approximately 5,000 cubic metres of sea water every 10 seconds

75 FACT It is rarely appreciated that the junction of Ahmadu Bello Way and Akin Adesola road a point along Bar Beach protected by the Shoreline Protection Works is actually THE HIGHEST POINT OF ELEVATION IN VICTORIA ISLAND The opposite end of Akin Adesola (Falomo Bridge ramp) is at an elevation 2m lower

76 A DISASTER AVERTED Given the severely depleted condition of Bar Beach in November 2005 (refer to slides 3 to 8) there was no present barrier to any storm condition whatsoever prior to the construction of the Shoreline Protection Works. The exceptional ocean surge of November 2006 would have engulfed a greater part of Victoria Island dumping 1,800,000 tons of sea water EVERY HOUR over the length of the beach during the peak of the storm.

77 SHORELINE PROTECTION WORKS CONDITIONS RECORDED DURING THE STORM OF 16 th 18 th NOVEMBER 2006

78 High elevated wave

79 The destructive power of the waves

80 Wave breaking at toe of structure

81 overspray crashing on the walkway

82 overspray repelled by beam

83 Yet still the road remains dry

84 SHORELINE PROTECTION PROJECT RECOGNITION AND AWARDS

85 CED FORUM AWARD 2006 AWARD OF EXCELLENCE

86 The West African Direct Marketing Award 2006 West Africa s Best Shoreline Project

87 SHORELINE PROTECTION PROJECT Mission accomplished The whole works were officially completed on 4 th December days ahead of schedule

88 EKO ATLANTIC CITY The protection continues

89 EKO Atlantic City development

90 The overall area to be reclaimed is 820 Hectares or 8,200,00m2. The total length of the Development is 6,500m and on average 1,260m wide. To the Southern Boundary is the main Revetment 6,500m in length. To the East Boundary is a Revetment of 920m in length and incorporates a large Marina with access to the sea. To the Northern Boundary is the existing Victoria Island and more specifically the existing Ahmadu Bello Way highway which is planned to be extended to an 8 lane highway known as Coastal Road under proposed Government planning. Incorporated in the Development will be central waterway 30m wide providing water transport facilities connecting 3 Marinas.

91 Other facilities comprise: An international standard road network Surface water drainage Dedicated electrical power generation plant and underground distribution. Water Supply, treatment and distribution mains Sewage collection mains leading to a modern plant. A network of service ducts to provide IT services. Post construction maintenance and management of the facility.

92 EKO ATLANTIC CITY LAY OUT

93 DREDGING OPERATIONS FOR EKO ATLANTIC CITY 93

94 SANDFILLED PORTION OF EKO ATLANTIC CITY 94

95 Work Done so far

96 Where we are Today

97 Award by Clinton Climate Initiative

98 THANK YOU EKO ONI BAJE.