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Introduction on the Delta Study of Viet Nam with respect to impacts assessment

Dr. Nguyen Anh Duc National CCAI Coordinator, Viet Nam National Mekong Committee The “ Study on the Impacts of Mainstream Hydropowers on the Mekong Study - MDS accumulative impact assessment of the entire cascade of 11 mainstream) initiated hydropower by Viet projects Nam focuses on the Mekongon the will Deltahave aof wider Viet Namscope and in termsCambodia. of the causes of impacts (not only focusing on mainstream” (the hydropower Mekong but Thealso “Study on other on areasthe Sustainable of development) Management and a widerand geographicalDevelopment scope of inthe terms Mekong of (impact MRCriver Councilincluding areas (Study Impacts of entireMainstream Mekong riverHydropower basin Projects” ) The MDS and the Council studies will complement each other during implementation). aimed to avoid duplication and independently and objectively cross-check relevant almost conclusions on the impact of mainstream hydropower

Mekong River Commission 6 – 8 October 2014 2 2nd Mekong Climate Change Forum Siem Reap, 1. To develop a complete database on baseline conditions for the LMB, particularly the Mekong Delta (floodplains of Viet Nam and Cambodia). 2. To quantitatively assess impacts of proposed mainstream hydropower projects on the downstream system including (i) the flow regime, (ii) transport of sediments and nutrients, (iii) biodiversit (v) fisheries, (vi) navigation, and(vii) related socio-economic issues. 3. To facilitate achievin y, (iv) water quality, of impact assessment of the proposed mainstream hydropowerg consensus projects on onthe the results Mekong Delta and determine avoidance, mitigation and enhancement measures Mekong River Commission 6 – 8 October 2014 through close consultation with3 relevant 2nd Mekong Climate Change Forum Siem Reap, Cambodia stakeholders. Inception PhaseInception . Identification of objectives, scope . Impact assessment methodology . Plan and Implementation Arrangements Baseline Assessment Phase . Baseline data collection and surveys . Linking water-related models to other sectors . Linking bio-physical models to socio-economic values . Development of assessment framework and indicators Impact Assessment Phase . Linking models, EIA framework for each sector . Scenario formulation . Scenario simulation . Impact assessment for each sector . Evaluation and prioritization of avoidance measures Avoidance, Enhancement and Mitigation Additional Studies . Avoidance measures . Enhancement measures Mekong River Commission 6 – 8 October 2014 . Mitigation measures4 2nd Mekong Climate Change Forum Siem Reap, Cambodia 2015

Avoidance, Enhance- ment and Mitigation

Impact Assessment

2014

Additional Studies

Baseline Assessment

2013

Inception Review and collect existing data

Agriculture SWAT Navigation Economy MikeBasin Fisheries

MIKE11 Bio-Diversity Mike Custumized Nutrients MIKE21C Sediment Livelihoods Outputs: Water Quantity and Quality and Quantity Water Outputs:

Additional studies Mekong River Commission 6 – 8 October 2014 2nd Mekong Climate Change Forum Siem Reap, Cambodia SWAT/ 1. Hydrological model ( MIKE Basin

MIKE21C 2. Basin simulation model ( 3. A 1-D-hydrodynamic SWAT)river model MIKE11/ ; Ecolab simulating flow and morphologyMikeBasin of SWAT/ the Mekong Mainstream ( ); MIKE Basin 4. Detailed 2-D hydrodynamic and

morphological models (MIKE11 MIKE11/ Ecolab simulating flow and morphology); of mainstream reservoirs and dams; MIKE MIKE21C 21/Ecolab 5. A coastal and estuary model ) (MIKE21 Mekong River Commission 6. Water quality) model6 – 8 October( 2014 2nd Mekong Climate Change Forum Siem Reap, Cambodia

Ecolab ) SWAT Water demands Land cover Q(t), Se(t), Tributaries N(t) Soil type Meteorology

DEM Hydrology (Q,H) MIKE BASIN

Structure Sediments Q(t), Se(t), N(t)

River network data Input Water Quality MIKE 11/ Cross-section Salinity Ecolab Mainstream Q(t), H(t), Se(t), N(t) MIKE 21C/Ecolab (Reservoirs)

Q(t), H(t), Q(t), H(t), Se(t), N(t) Se(t), N(t) MIKE11/ MIKE 21/Ecolab Delta (Tonle Sap) Ecolab

Q(t), H(t), Se(t),N(t),Sa(t) East Sea Coastal MIKE 21/ MIKE 21 Ecolab Q(t), H(t), Mekong River Commission 6Se(t),N(t),Sa(t) – 8 October 2014 2nd Mekong Climate Change Forum Siem Reap, Cambodia 1. Baseline Scenario, year 2008 conditions (will be extended to 2011/2012) 2. Impacts of LMB Hydropower cascade; combinations of dams covering different levels of impacts; operations and dam-break 3. Cumulative impact with others: change, hydropowerChinese development cascade ofin reservoirs,tributaries, water abstraction/ diversion in the Climate catchments, basin changes (hydrology and water demands) etc.

Climate change level rise 4. Assessing levels of: Basin-wideimpacts of developmentchange + Sea

Mekong River Commissionactivities to the Mekong Delta 6 – 8 October 2014 2nd Mekong Climate Change Forum Siem Reap, Cambodia Hydrological Impact Assessment Nutrient and Sediment Assessment Fisheries Assessment Biodiversity Assessment Agriculture Assessment Navigation Assessment Economy Assessment Livelihood Assessment

Mekong River Commission 6 – 8 October 2014 2nd Mekong Climate Change Forum Siem Reap, Cambodia Biodiversity assessment

Mekong River Commission 6 – 8 October 2014 2nd Mekong Climate Change Forum Siem Reap, Cambodia Biodiversity Assessment Framework Biodiversity Model Impact Causative Factors outputs Analyses

Variations in seasonal Flows Landscape – Hydrology Inundation depths Level habitat

Extent of Flooded Areas

Timing Tonle Sap Flow Reversals Biodiversity ` Hotspot Sediment Transport Floodplain Sedimentation

In Chennel Feature Morphology Rare & Vulnerable Water Species quality Erosion

Nutrient Deposition Sediment and Nutrient Migration Routes Transport Physical Barriers Mekong River Commission Habitat connectivity 6 – 8 October 2014 2nd Mekong Climate Change Forum Siem Reap, Cambodia Mekong River Commission 6 – 8 October 2014 2nd Mekong Climate Change Forum Siem Reap, Cambodia #Y #Y #Y Sisophon #Y Stung Treng %#Y Siem Reap #Y

#Y Kampong Luong #Y Kampong Thom #Y #Y #Y

% Kratie #Y % #Y #Y #Y Kampong Chhnang #Y%

AreaKampong Cham (%)#Y #Y Prek Dam (km2) % PHNOM PENH #Y Total wetlands area in 19,985 #Y% Legend the floodplain#Y of the#Y #Y kb23_mfld_00 MK delta of VN VALUE #Y No flood Area impacted #Y 2,251 11.3 Tan Chau 0 - 0.5m Chau Doc % #Y 0.5 - 1.0m Chau Doc #Y% #Y 1.0 - 1.5m #Y #Y 1.5 - 2.0m #Y #Y #Y #Y My Tho 2.0 - 2.5m Ha Tien #Y #Y 2.5 - 3.0m 3.0 - 3.5m #Y #Y #Y Legend3.5 - 4.0m µ kb2300-rf4.0 - 5.0m Value #Y 5.0 - 6.0m Tra Vinh Giam 6.0 - 7.0m Kilometers 7.0 - 8.0m #Y #Y 012.5 25507510025 50 75 100 >8.0mTang Soc Trang Ca Mau Mekong River Commission 6 – 8 October 2014 2nd Mekong Climate Change Forum Siem Reap, Cambodia Change in Flooding extent of Tram Chim Hotpots

Mekong River Commission 6 – 8 October 2014 2nd Mekong Climate Change Forum Siem Reap, Cambodia  Field surveys –to gather additional data wildlife and vegetation

communities Bassac Marsh  Dry season (Feb –Apr)  Transition period (May – June)

 Rainy season (Aug –Sep) Lang Sen Tram Chim

 Wetlands classification maps update –based on the most recent and Ha Tien available aerial photography and/or • Othersatellite sources: imagery of Additional the Delta and data the flood plains needed for RTE species habitat Thanh Phu usage characterization acquired from review of available scientific publications and study reports Fisheries assessment

Mekong River Commission 6 – 8 October 2014 2nd Mekong Climate Change Forum Siem Reap, Cambodia Drivers Causative Factors Sectors

River flows volumes

Computation Capture floodplain inundated and duration fisheries Flows Professional yield inundation depths judgment

Timing and duration floods Computation Timing and duration of low flow periods Professional Aquaculture judgment Production Sediment, Salinity Intrusion Nutrient River sediment deposition, nutrient

Professional judgment Migration Routes Diversity and Fish Physical Barriers Habitat connectivity Migration Mekong River Commission 6 – 8 October 2014 2nd Mekong Climate Change Forum Siem Reap, Cambodia Mekong River Commission 6 – 8 October 2014 2nd Mekong Climate Change Forum Siem Reap, Cambodia #Y #Y #Y #Y #Y Sisophon Stung Treng % #Y Siem Reap

#Y

Kampong Luong Kampong Thom #Y #Y #Y Kratie #Y #Y % #Y #Y Kampong Chhnang % #Y Kampong Cham #Y % #Y Prek DamItem Area#Y (%) PHNOM(km2) PENH % #Y Legend Total fish habitat#Y area #Y #Y 38,469 100 kb23_mfld_00 % VALUE in the MK#Y delta No flood Tan Chau 0 - 0.5m #Y Ho Chi Minh City 0.5 - 1.0m Chau Doc #Y 1.0 - 1.5m Area impacted % 1,537 4.07 1.5 - 2.0m #Y #Y My Tho 2.0 - 2.5m Ha Tien #Y % 2.5 - 3.0m #Y #Y 3.0 - 3.5m #Y Legend #Y #Y #Y 3.5 - 4.0m #Y #Y kb2300-rf4.0 - 5.0m µ Value 5.0 - 6.0m #Y #Y Tra Vinh Giam #Y 6.0 - 7.0m Kilometers 7.0 - 8.0m 025507510012.5 >8.0mTang #Y Soc Trang Mekong River Commission Ca Mau 6 – 8 October 2014 2nd Mekong Climate Change Forum Siem Reap, Cambodia #Y #Y Mekong River Commission 6 – 8 October 2014 2nd Mekong Climate Change Forum Siem Reap, Cambodia 22 Thank you for your kind attention