POTENTIAL IMPACTS OF THE SUPER SEA DYKE (SSD) AT RACH GIA BAY ON THE VALUES OF MANGROVES IN KIEN GIANG PROVINCE - MEKONG DELTA, VIETNAM

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1 1 POTENTIAL IMPACTS OF THE SUPER SEA DYKE (SSD) AT RACH GIA BAY ON THE VALUES OF MANGROVES IN KIEN GIANG PROVINCE - MEKONG DELTA, VIETNAM Dr. Trinh Thi Long SOUTHERN INSTITUTE OF WATER RESOURCES RESEARCH 658 VO VAN KIET, DISTRICT 5, HO CHI MINH CITY ttlongvn@gmail.com Website:

2 Outline The Super Sea Dike (SSD) Ability of freshening water The fate of mangroves and their lost values (Total Economic Value) Summary 2

3 TRUNG QUỐC MYANMAR LÀO VIỆT NAM HÀ NỘI Hải Phòng VIENTIANE Đồng Hới Hải Nam THÁI LAN BANGKOK Huế Đà Nẵng BIỂN ĐÔNG VỊNH THÁI LAN PHNOMPENH TP.Hồ Chí Minh Vũng Tàu Cần Thơ Nha Trang GHI CHÚ Lưu vực sông MeKong Đồng bằng sông Cửu Long

4 INCREASING POPULATION URBANISATION INDUSTRIALISATION CLIMATE CHANGE DROUGHT SALINITY INTRUSION ACID WATER SPREADING INCREASING WATER DEMAND POOR W.W MANAGEMENT POOR RUNOFF WM? WATER SCARCITY

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6 1 m sea level rise Land area inundated: 39% 35% PEOPLE DIRECTLY AFFECTED Source: MONRE 2009 & 2012

7 over 4.7 million people affected, or 82% of all affected people in Viet Nam The sea level rise impacts fall mainly in the Mekong River Delta, where 85% of the total National inundation will affect all provinces and cover 12,376 sq km.? Source: ICEM International Centre for Environmental Management, 2007

8 OP1: surface water area: 357 km ² Capacity: 600 Million m3 length 30 km OP2: surface water area:425 km ² Capacity: 795 Million m3 length 31.8 km OP3: surface water area:823 km ² Capacity: 2.58 billion m3 length 47.5 km OPTION 1

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10 Tole Sap lake Karatie 1D-hydraulic network Can Dang from Karatie to the East Sea more than 2500 branches of rivers and canals, cross-sections and more than 2500 structures For water discharge, the boundaries have been taken at Karatie, Tole Sap lake and East Vai Co river. For water level, the boundaries havebeen taken at the boundaries from Soai Rap mouth to Vinh Te mouth. 1 D

11 COMBINED 1D & 2D The 2D-hydraulic network set for the entire Bay of Rach Gia The network is divided into 5493 irregular triangular elements and 2864 computation points At the Rach Gia Bay area, the boundaries are getting from the 2D model for the entire East Sea. Besides, the boundaries inside the project area are calculated from the ability of water supply and drainage in the fields

12 The 2D model network of the 3 options

13 ABILITY OF FRESHENING WATER Vi tri cong [g/l] Rach Gia [g/l] OP1&2: OP3: 2 months 5-7 months 8-9 months Vi tri June cong [g/l] Rach 2007 Gia [g/l] July 2007 August 2007 September 2007 October 2007 November 2007 HOW ARE THE MANGROVES? nd June Mekong 2000Climate Change Forum July 2000 August 2000

14 FAO and Wetlands International, 2006 Biosphere Reserve 0,2% ha

15 LOST OF MANGROVE FOREST OP 1&2: ha OP 1&2: ha VALUE? 15

16 Total economic value (TEV) Consumptive Use value (UV) Non-Consumptive Use Value (NUV) Direct use value (DUV) Indirect use value (IDUV) Option value (OV) Bequest value (BV) Existence Value EXV TEV = UV+NUV = (DU + IDUV) + (OV + BV + EXV)

17 Seafood production generated by mangrove ecosystems: direct biophysical support to capture fisheries, and natural products and ecological services sustaining aquaculture. Source: Patrik Ronnback, 1999

18 AQUACULTURE - This freshening water will - break aquaculture planning of the province, altering ecosystems and natural conditions, affecting the structure of aquaculture.

19 AQUACULTURE AREAS AFFECTED (OP1 & OP2)

20 AQUACULTURE AREAS AFFECTED (OP3)

21 Lost food providing, place of birth, nurturing nursery for Estuary juvenile fish and species of coastal fish due to lost of mangrove forest, The life cycle of the crab Scylla olivacea Estuary Megalopae( final larval stage) 5 9 days 1st crab instar days Since residing in the mangroves into adulthood crab days 14 days Adult mud crabs move offshore Offshore Egg and zoea larval stage Source: Moser (2001) Macintosh: from Moser (2001) Egg-bearing female crab

22 Value the Mangroves for 1 ha Value items Value of 1 ha (M.VND/year) OP 1&2 (M.VND/year) OP3 (M.VND/year) Min Max Min Max Min Max A Direct use value 1 Wood value Firewood value Medicines value ,038 3,912 3,716 4,785 4 Sea food value , ,666 23, ,176 B Indirect use value 1 Carbon accumulation value , , , ,024 2 Tourism value ,572 5,129 5,592 6,275 3 Protection value ,482 40,710 45,851 49,799

23 LOST VALUE / YEAR(USD) Value items OP 1&2 OP 3 Damage overcome lost Damage overcome lost OP1&2: 6.6 million USD/year A Direct use value Wood value Firewood OP3: 8 million USD/year 3 Medicines Sea food B Indirect use Carbon 1 accumulation value Tourism value Protection value Total

24 SUMMARY Building the dike will seriously impacts on the Mangroves in Kien Giang coastal areas of the Mekong Delta. The average lost up to 6.6 million USD/year for the OP 1&2 and up to 8 million USD/year for the OP3 It needs to be carefully consider whether or not to buid the dike to conserver Mangrove forest and support aquaculture in the region.

25 25 Thank you very much for your attention!