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Southern Institute of Water Resources Research - Water related issues in the Mekong Delta

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This presentation is part of the ProSPER.Net Young Researchers' School 2017 ‘Water Security for Sustainable Development in a Changing Climate’.

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Southern Institute of Water Resources Research - Water related issues in the Mekong Delta

  1. 1. 1 1 ‘Water Security for Sustainable Development in a Changing Climate’ Discussion about water issues under changing climate TOPIC: WATER RELATED ISSUES IN THE MEKONG DELTA By: To Quang Toan, toan_siwrr@yahoo.com VIỆN KHOA HỌC THỦY LỢI MIỀN NAM Southern Institute of Water Resources Research 658 Vo Van Kiet street, Dist 5, HCM city Tel: 08 39238320 Fax: 0839235028 Webs: www.siwrr.org.vn 2 1. Mekong Delta and water related issues 2. Unusual climate and hydrological condition in Mekong delta 3. Vietnam national projection for climate change and sea level rise 4. Change of hydrological flow: impact to flood and dry season flow 5. Salinity intrusion status 6. Change on sediment, riverbank and coastal zone erosion impacts 7. Sea water level rise, land subsidence and typhoons 8. Impact of climate change to Mekong delta 9. Conclusion and delivery messages CONTENTS 3 MEKONG DELTA AND WATER RELATED ISSUES 1 4 Ú Ú Ú Ú Ú Ú Ú ÚÚ Ú Ú Ú ÚÚ Ú â â â â Pakse Kratie Ch©u §èc Jinghong Chiang Saen Luang Prabang T©n Ch©u H Néi Bangkok Vientiane Phnom Penh Trung Quèc Myanma Th¸i Lan Campuchia ViÖt Nam L o QuÇn ®¶o Ho ng Sa QuÇn ®¶o Tr−êng Sa BIÓN §¤NG BIÓN T¢Y PhÇ nth−î ng l−u tõ biª ngií iTrung Qu èc vÒ ®Õn Kra tie PhÇn th−îng l−uthué cTrung Quèc vMya nma PhÇn th−îng l−u thuéc Campuchia ë d−íi Kratie Vïn g®ån gb»n gCh©u thæ s«n gMªC«n g §ång B»ng S«ng Cöu Long, ViÖt Nam BiÓn hå To nle Sa p C¸c ®Æc tr−ng chÝnh DiÖn tÝch l−u vùc: 795.000 km (21) ChiÒu d i dßng chÝnh: 4.800 km (12) L−u l−îng b×nh qu©n h ng n¨m: 15.000 m /s 16% 2% 18% 35% 18% 11% 2 3 70 0 70 140 210 280 350 Kilometers L−u vùc s«ng Mª C«ng h¹ thuéc L o, Th¸i Lan, Campuchia v VN Th−îng l−u tõ TrungQuèc ®Õn Kratie Th−îng l−u §BSCL thuéc Campuchia sau Kratie §ång B»ng S«ng Cöu Long v Phô cËn BiÓn Hå Tonle Sap Th−îng l−u vùc s«ng Mª C«ng thuéc TrungQuèc v Myanma Vïng Ch©u thæ Mª C«ng C¸c nh¸nhchÝnh trªn l−u vùc Ú VÞ trÝ c¸c tr¹m quan tr¾c trªn dßng chÝnh Mª C«ng â Th nh phè, thñ ®« Ranh giíi c¸c qu«c gia trong khu vùc Dßng chÝnhs«ng Mª C«ng S N EW B¶N §å L¦U VùC S¤NG M£ C¤NG GHI CHó Total area: 3.9 million ha Population: 18 million people Cultivated area: > 2 million ha of rice, up to 7crops per 2years The Mekong Delta Key figures of in the Mekong Delta 5 Area: 12% of Vietnam Population: 21.5% of Vietnam Contribute 50% of food production, 90% of exported rice come from Mekong delta 70% of fruit production >60% of the aquaculture production (catch 44%, culture 75%) and 80% national expoted value Month Problems 1 2 3 4 5 6 7 8 9 10 11 12 Flood Salinity Intrusion Acid sulphate soil and acid water Drought River bank erosion Sedimentation Water pollution Related problems in the Mekong delta In addition: upstream development, climate change-SLR, land subsidence… 6
  2. 2. 2 7 UNUSUAL CLIMATE AND HYDROLOGICAL CONDITION IN MEKONG DELTA2 Unusual climate condition in the South of Vietnam High temperature: 35-37 deg., 20ys Cool temp.: Dec-Jan 16-17 deg., 10ys. High spring tidal during Oct to Feb: 170 cm at Phu An, while previous calculation max WL with P1% 130 cm Rain fall distributed infrequent: start earlier some time, (as of 2009, 2010, 2016 P>50mm) and stop later (2006, 2016), Continuos High flood 2000 to 2002 Severely drought: 1998, 2005, 2010, 2012 and typical 2016 The longest low flood period from 2003-2010, 2012-present Typhoons and hurricanes increase in number and intensity: Linda 5 Nov 1997, Durian 17Nov 2006, Nov 2008 Unusual flow of the Mekong river Mekong delta flood 2011 Pakhar Storm 1st April 2012 Sources: www.nld.com.vn Climate change in the Mekong delta Sea water level rise about 3 mm/year 12 VIETNAM NATIONAL PROJECTION FOR CLIMATE CHANGE AND SEA WATER LEVEL RISE3
  3. 3. 3 Biến đổi khí hậu - NBD 13 (MONRE 2016) o RCP4.5:To increase 1,7oc*1,9oc, Rainfall increase 5*15%, SLR 32* 78 cm o RCP8.5:To increase 3,0oc*3,5oc, Rainfall increase >20%, SLR 48*106 cm 14 CHANGE OF HYDROLOGICAL FLOW FROM MEKONG RIVER: IMPACT TO FLOOD AND DRY SEASON FLOW 4 abnormal operation of hydropower dams Abnormal water storage may change a normal hydrological year to a droughty year and opposite way - may resulted from close dam at completed construction, trial operation, other purposes 15 3 operated perious of China dams in 2016 . 2: Hydrological change Dry season flow in 2015-2016 China dams operation 2nd times (from 23- 28/2/2016) 3th (from 9/3/3016) 1st times (from 19- 27/1/2016) Operation scenario: early/late water retention Early water retention operation may reduce the discharge at early stage of rainy season, salinity water may happen a longer period 17 Late water retention operation may reduce the discharge at early of dry season, salinity intrusion happen earlier dry season Late storage water Early storage water Natural flow condition With flow regulation 18 SALINITY INTRUSION STATUS 5
  4. 4. 4 Salinity intrusion in dry season 2015-2016 • Potential salinity intrusion (without salinity intrusion control systems) in 2015-2016 • Salinity concentration was too high aquaculture cultivation plan is inactively Source: SIWRR Salinity concentration was too high, over suitable thresholds for shrimp cultivation Orchard areas were affected by saline intrusion to reduce yield product Province Number of family (household) Number of family lack of drink water in 2016 (household) Percentage of family lack of water (%) Ben Tre 300.000 86.200 28.7 Soc Trang 311.000 43.000 13.8 Kien Giang 415.000 25.000 6 Tra Vinh 244.000 21.400 8.8 Long An 351.000 15.500 4.4 Ca Mau 289.000 14.500 5 Tien Giang 408.000 7.000 1.7 Bac Lieu 209.000 3.200 1.5 Vinh Long 247.000 2.500 1 Hau Giang 182.000 2.500 1.4 Total 220.800 7.5 B n Tre, Sóc Trăng, Kiên Giang, Trà Vinh… Number of schools, clinics hotels, factories were also lack of water supply 3: Salinity intrusion In recently period Affected to drinking water supply in 2016 21 CHANGE ON SEDIMENT, RIVERBANK AND COASTAL ZONE EROSION IMPACTS6 TT Scenario Description Sediment load at Kratie (Mil ton) Reduction vs 1998 condition (%) Reductio n vs present conditio n (%) Max Min Averag e 1 KB0 Baseline – China dams (CND) 97,0 34,0 59,6 63% 2 KB1 CND+Xayabury 89,3 31,5 54,5 66% 9% 3 KB3 CND+ (Pakbeng, Luang Prabang, Xayabury) 81,7 28,4 48,3 70% 19% 4 KB10 CND+ 10 mainstream hydropower dams in Lao PDR 58,3 21,3 34,9 78% 42% 5 KB12 CND+ 12 mainstream hydropower dams 49,1 17,7 29,4 82% 51% 6 KB12+ CND+ 12 mainstream hydropower dams+tributaries dams 29,4 11,1 17,9 89% 58% Other study (MDS) 13,88 mil tons 4: Change on sediment Impact of upstream development Sediment change based on some simulation scenario (KC08.13/11-14, SIWRR) 4: Change on sediment Existing of mangrove forest belt 23 Lost 500 ha/year 24 SEA WATER LEVEL RISE, LAND SUBSIDENCE AND TYPHOONS7
  5. 5. 5 25 5: Sea level rice, land subsidence and typhoon Land subsidence To what extent? 1.6 – 2.5 cm/year Delta now faces the twin threats of subsidence and rising sea levels. Sinking at rates many times faster than global sea level is rising”. Sea water level rise (1,6-2cm/year??) Station Period Rate of Sea WLR (mm/year) Vũng Tàu 1980-2015 4.85 Gành Hào 1996-2015 16.6 2000-2015 19.6 (2cm/year) Sông Đ c 1996-2015 13.3 2000-2015 11 R ch Giá 1996-2015 2.9 2000-2015 5.3 (Na Uy: 1,9 – 2,8 cm/năm) (ICEM: 1,9 – 2,8 cm/năm) Natinal projection for sea level rise: 2100: 100 cm 2030: 17 cm Max high of wave in KB1 (level 13): 3.5 m WAVE LEVEL IN TYPHOON 5: Sea level rice, land subsidence and typhoon Typhoon e.g: Typhoon wind speed level 13 Distribution of water level rise in high typhoon KB1 (level 13) 5: Sea level rice, land subsidence and typhoon Typhoon e.g: Typhoon wind speed level 13 28 IMPACT OF CLIMATE CHANGE TO MEKONG DELTA 8 Agriculture and aquaculture development in Mekong delta 29 Change of salinity intrusion by concentration in simulated scenarios
  6. 6. 6 Change of salinity extent in 1g/l Tidal inundation change in SLR scenarios Flood changes in case of Mekong river flood as year 2000 + SLR Possible impact of Climate change and Sea level rise to the Mekong delta With the pre-simulated results on the impact of CC&SLR to the Mekong delta it may concluded that there will be a large change to the natural conditions (soils - inundated area, water resources, floods, salinity intrusion, water quality…), to the ecology conditions (plants, animals and microorganism, insects…) and affected to infrastructure, socio-economic and sustainable development in the Mekong delta. Posible impact to agriculture in dry season Evaluation the impact of SLR to Rice cultivation area
  7. 7. 7 Rice yield reduction and rice production reduction Impact Type of land use Affected area (ha) Rice yield reduction (T/ha) Rice production reduction (Ton) Fresh turn to salty 3-rice crops 14180 -6.0 -85081 Brackish turn to salty 3-rice crops 71290 -5.5 -392095 Fresh to brackish 3-rice crops 103135 -1.2 -123762 Brackish to fresh 3-rice crops 77 1.1 84 Salty to brackish 3-rice crops 0 3.5 0 Salty to fresh 3-rice crops 0 5.0 0 Fresh to salty WS-SA 3750 -6.0 -22498 Brackish to salty WS-SA 32891 -5.5 -180899 Fresh to brackish WS-SA 75053 -1.2 -90064 Brackish to fresh WS-SA 4 1.1 4 Salty to brackish WS-SA 0 3.5 0 Salty to fresh WS-SA 0 5.0 0 Fresh to salty WS-SA 40 -6.0 -242 Brackish to salty SA-M 23855 -5.5 -131203 Fresh to brackish SA-M 11848 -1.2 -14217 Brackish to fresh SA-M 0 1.1 0 Salty to brackish SA-M 0 3.5 0 Salty to fresh SA-M 0 5.0 0 Total 336.123 -1.039.973 Posible impact to agriculture in flood season Impact to bio-diversity Changes of inundation extent in Cape Camau Park Possible impact to biodiversity (e.g Cape Camau Park) The living environmental condition for reptiles and crustaceans is shallow and temporary daily inundation. The earned foods for births and other animals are also come from the similar conditions. What is happening here? Impact to infrastructures Increase the flooding condition of cities and towns in the delta: Cần Thơ, Mỹ Tho, Bạc Liêu, Long Xuyên... Impact to infrastructure of roads and others; Impact to current hydraulic structures: the crest of the salinity intrusion gate is about 2.0-2.5m – water would run over the top of sluice gate Current dikes and roads would not meet the SLR condition ... Flooding condition in Can Tho city in SLR scenarios
  8. 8. 8 Flood warning mark 44 CONCLUSION AND DELIVERY MESSAGES 9 45 Inside Mekong delta: Land subsidence/ tidal inundation/ salinity intrusion/ drought/water quality… 6: Challenges: Conclusion Delivery messages The Main stream Mekong hydro power cascades Cut ‘MekongMekongMekongMekong DragonDragonDragonDragon’ INTO PIECES - loss the God’s Gift to Mekong’ people: water with natural flow, protit and fertilizers - loss the ability to forecast and do early warning for floods and drought. – With reservoir water levels can not predict the real discharge. Mekong hydropower Cascades cause a considerable losses of sediments, fisheries, agriculture causing drought, salinity intrusion, erosion, environmental problems. Water resources development in the Mekong basin needs an integrated approach. Give a hand to save the Mekong River! 46