E-flows Yellow River (downstream) pilot

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E-flows Yellow River (downstream) pilot

  1. 1. ACEDP Project: EnvironmentalFlows in The Lower Yellow RiverJiang XiaohuiYRCCWorkshop, Beijing2012 Feb 23
  2. 2. ContentsBackgroundGeneral environmental flow assessmentmethodologyBrief description of workExperience and recommendations
  3. 3. Background Study Area Survey N Site three Lijin Lijin Zibo Luokou Jinan Liaocheng , Tai an Aishan Sunkou Dongping Dongping Lake Dam Xiaolangdi Gaocun Sanmenxia River Qinyang Kaifeng Huayuankou Hydrological station Luoyang Sanmenxia Zhengzhou City Lake
  4. 4. Lower Yellow River Flow Issues• “Mother River” – High water demand – High degree of regulation• Climate change and human activities – Flows reducing over past 50 years, cease to flow sometimes from 1970s to 1990s• Sediemnt – A very high sediment load to the lower river,flood• Yellow River Delta – a dynamic estuarine Ramsar wetland – Depends on sediment supply for growth• Riverine wetlands – Mostly disconnected due to flood dyke construction• Aquatic ecosystem – lost diversity
  5. 5. In China there is a strong awareness of the need and importance ofenvironmental flows. Environmental flow assessments have been undertaken ina number of rivers,
  6. 6. General environmental flow assessment methodologyEnvironmental flow methods used in China:• Hydrological--Tennant• Hydraulic rating-Wetted perimeter method, R2CROSS(Focus on one or a few key species)• Habitat simulation-IFIM (focus on one or a few key species)• Holistic• --Consider the entire ecosystem• --Not constrained by the analytical tools• --Consider other water user• --expensive
  7. 7. General environmental flow assessment
  8. 8. Brief description of work Select sites and reaches
  9. 9. Field trip 、 sample 、 workshop and literature search
  10. 10. Reaches River channel 4 3 Delta 2 wetlands Dongping Lake 1 ZhengzhouMengjin Kaifeng wetlandswetlands wetlands
  11. 11. Identify ecological assets
  12. 12. River asset• A river asset is any attribute of the natural ecosystem of value to society. The value could be ecological, social and/or economic.• River assets include species, biological communities, habitats and ecosystems of conservation importance (collectively referred to as “conservation assets”).
  13. 13. Assets in the low Yellow River• Fish species, e.g. Yellow River Carp• Wetland vegetation• Birds• Spawning process• Sediment transport• Water quality• Geomorphology
  14. 14. Develop conceptual models linking asset health and flow componentsGeomorphology, plants, fish, macroinvertebrates, water quality, birds…
  15. 15. Flow regime Low flows Flow pulses High flows Floods Sediments from Maintain depth upstream and of water in Food resources catchments refuge pools increase. and DO decreases Maintain Stimulate Maintain larval Maintain backwater refuges adult fish spawning and and food resources for fish. population juvenile habitat in Fish mortality increases. river channelFigure. The links between individual flow components and flow requirements for carp
  16. 16. Table. Flow components and hydraulic criteria relevant to Yellow River Carp requirements. D = depth, V = velocity Objective Flow Hydraulic criteria Timing component Maintain sufficient water Low flow Max D > 1.5 m Nov-Mar, depth in pools for large V: 0.1-0.8 ms-1 April-June bodied fish Stimulate spawning Flow pulse D: 1-2 m at peak of flow April - June pulse. Inundated beach area, and increase back water V<0.3 ms-1 Provide new habitat and High flow Average D > 0.7 m; July-October feeding opportunities for V: 0.3 ms-1-1ms-1 fish Provide new habitat and Flood Average D > 0.8 m; July-October feeding opportunities for V: 0.5 ms-1-1.2ms-1 fish, but increased sediment and low DO may increase mortality
  17. 17. No. Flow component Hydraulic/hydrologic criteria F1 Cease-to-flow; Low flow Q ≥ YRCC warning standards of low flow emergency; maintain area‡ ≥ critical depth* at pool crossings (specified each month)Fish F2 Low flow Maintain area‡ ≥ critical depth* with V ≤ 2.0 m/s1,2 F3 High flow, high flow recession Maintain longitudinal connectivity and area‡ ≥ critical depth* over barriers (shallow areas) F4 Low flow Maintain area‡ with depth ≥ critical depth* in pools F5 High flow pulse Achieve area‡ with depth ≥ critical depth* over barriers (shallow areas) F6 High flow Maintain area‡ with D = 0.5 – 1.0 m1,2 and V ≤ 1.4 m/s1,2 F7 High flow Maintain area‡ with velocity 1.0 – 2.0 m/s1 F8 High flow pulse Maintenance of appropriate† salinity gradient in estuary F9 Low flow and high flow Maintain area‡ of D ≥ 1.5 m1,2 and V ≤ 1.0 m/s1,2 F10 Low and high flow pulses Achieve sufficient depth* to replenish/maintain water in river associated wetlands and backwaters F11 Low flow and high flows Maintain adequate cross-sectional area/discharge* to transport nutrients required to sustain primary productivity F12 Bankfull 2,600 - 4,000 m3/s - see Geomorphologic objective G1 F13 Bankfull 2,600 - 4,000 m3/s - see Geomorphologic objective G2 F14 High flow See Vegetation objective V1 F15 High flow and low flow See Vegetation objective V7 F16 Low flow Maintain mean pool velocity ≥ 0.01 m/s F17 High flow and low flow Sufficient discharge* to maintain morphology in and around the estuary mouth F18 Bankfull 2,600 - 4,000 m3/s - see Geomorphologic objectives G3 and G4
  18. 18. Plants No. Objective Flow component Hydraulic/hydrologic criteria V1 Maintain submerged aquatic High flow Inundation to ≤ 1 m vegetation (e.g. Vallisneria, Potomageton and Myriophyllum spp.) V2 Maintain meadow vegetation High flow Inundation to ≤ 0.3 m V3 Maintain Tamarix/Salix shrubland High flow, low flow and low 100% of time shallow groundwater; Jul – Sep flow pulse waterlogging; inundation by summer flow pulse events ≤ 30 days; soil salinity 10 – 30 psu V4 Maintain Tamarix/Salix woodland High flow, low flow and low 100% of time shallow groundwater (at 1.5 – flow pulse 3.0 m); inundation by summer flow pulse events ≤ 30 days; soil salinity 10 – 30 psu V5 Maintain sand flats High flow and low flow 100% of time shallow groundwater (at ≤ 1.8 m); soil salinity ≥ 30 psu V6 Maintain Suaeda salsa High flow pulse Inundate once per year for ≤ 30 days or 30 to 180 days of varying depth from -0.1 to +0.1 m; 100% of time shallow groundwater (at 1.8 m); soil salinity 5 – 30 psu V7 Maintain Phragmites australis High flow and low flow 100% of time waterlogging; varying grassland inundation 0 – 0.5 m deep (1.5 m max.; 0.3 m mean) in summer
  19. 19. Birds No. Objective Flow component Hydrologic/hydraulic criteria B1 Foraging Low flows Expose Carex B2 Foraging Low flows Shallow water (<0.3 m) over submerged or emergent aquatic plant community with mud or sand base B3 Foraging Low flows Expose mudflats B4 Wintering area Low flows Maintain ice free water bodies* B5 Food supply and breeding High flows Inundate areas of submerged macrophytes (Vallisneria, Phragmites, Typha, Carex, Tamarisk) B6 Foraging High flow recession Gradually receding water levels from Bankfull peak B7 Mudflat foraging habitat Bankfull An annual event that creation supplies enough sediment load to at least maintain delta area B8 Summer-autumn habitat Bankfull An annual event to area inundate backwaters and wetlands
  20. 20. Geomorphology Geomorphologic-based objectives and flow requirements.No. Objective Flow Hydrologic criteria Mean annual Inter-annual Timing Reach Reference component frequency/duration frequencyG1 Scour and deposition processes Bankfull 2,600 - 4,000 m3/s ≥ 1 per year / ≥ 1 day* ≥4 in 5 years Jun – Reach 1 Richards et al. to maintain dynamic and diverse duration Sep (2002) habitats in the channel and connected floodplains 3G2 Maintain channel capacity at Bankfull 2,600 - 4,000 m /s ≥ 1 per year / ~10 – 30 ≥4 in 5 years Jun – All Liu et al. (2006) 3 4,000 m /s days duration; Sep reaches rates of rise and fall within natural range 8G3 Seaward progradation of the Bankfull Sediment load >3.45 × 10 ≥ 1 per year ≥4 in 5 years Jun – Reach 4 Wang K et al. delta tonnes at Lijin; event mean Sep (2007); Wang et sediment concentration al. (2010) 3 ≥ 35 kg/mG4 Flow into delta wetland Bankfull >3,000 m3/s to allow ≥ 1 per year / ≥ 10 days* ≥4 in 5 years Jun – Reach 4 Jiang Xiaohui channels to maintain channel gravity flow days duration (or as Sep (YRCC, pers. form (and also provide required) comm., November freshwater and nutrients to the 2010) delta wetlands)* Based on expert opinion; refinement of this criterion will require investigation.
  21. 21. Set objectives for each asset and important process•Ecological management objectives (what level of river health is desired? taking account of constraints, and other uses of the river) •Hydraulic/hydrologic objectives to achieve the ecological objectives
  22. 22. Set objectives• 18 Fish objectives• 6 Water quality objective• 8 Bird objective• 8 Macroinvertebrate objectives• 4 Geomomorphic objectives• These can be rationalised to a smaller group for evaluation – 13 objectives
  23. 23. Key Obj. met Objectives description Flow componentobj.A F1; M1 Prevent habitat loss through drying of shallow areas Cease to flowB B1; B2; B3 Expose Carex and mudflats; shallow water over submerged aquatics Low flowC F2 Maintain shallow habitats with moderate-high velocity for shallow water dwelling species Low flow and spawners during low flow periodsD WQ1, WQ2, WQ3, Dilute contaminants to Grade III standard Low flow and high flow WQ4E V3; V4 Maintain Tamarix/Salix shrubland and woodland Low flow and high flowF M2; M5; F3; F4; F11; Maintain reasonable area of habitat for most of the time for longitudinal connectivity, Low flow and high flow F16 survival of large-bodied fish, maintenance of primary productivity in the estuary; and maintenance of DO levels in deep poolsG F6; F7; F9 Provide suitable habitats for spawning, allow access of large bodied fish to backwater High flow and wetland habitats; maintain downstream transport of semi-buoyant eggs within the water column; and sufficient depth in pools for large-bodied fishH V1; B5; M3; M4; F14 Maintain submerged aquatic vegetation High flowI V2 Maintain meadow vegetation High flowJ M6; F8 Maintain favourable salinity at estuary and mouth for rearing of Chinese shrimp; and High flow maintain salinity gradient for anadromous fish spawning migrationK V3; V4; F10 Maintain Tamarix/Salix shrubland and woodland; and replenish/maintain water in river Low flow pulse associated wetlands and backwatersL F5; F10 Stimulate spawning, migration (anadromy and potadromy) and maintain habitat High flow pulse continuity between near-shore/estuarine and freshwater habitats to allow free upstream passage; and replenish/maintain water in river associated wetlands and backwatersM G1, G2, G3, G4, Scour and deposition processes to maintain dynamic and diverse habitats in the Bankfull WQ6; B6; B7; B8; M7; channel and connected floodplains; maintain channel capacity at 4,000 m /s; seaward 3 M8; F12; F13; progradation of the delta; allow flow into delta wetland channels for habitat provision and physical maintenance; provide low velocity littoral habitats for small bodied species; and maintain shallow pool crossings with moderate-high velocities
  24. 24. Hydrological and hydraulic modellingDetermine the characteristics of the flows (magnitude, duration, frequency and timing) required to meet the objectives
  25. 25. Hydraulic modelConvert Hydraulic index to flow index • 1-dimension – Inexpensive – Cover a long reach – Cross-section average Mean velocity V Depth D • 2-dimension – Expensive – Cover a short reach – Depth-averaged Mean velocity V Depth D
  26. 26. 1-D HEC-RAS model output
  27. 27. 2-D River2D model output Mesh Depth Velocity Flow direction
  28. 28. Lower Yellow River data• 370 cross-sections – Surveyed every year • Use for 1-D model of whole river• 3 sites surveyed in detail – Lijin – Huayuankou – Yiluo junction • Use for 2-D model
  29. 29. Establish flow rules Integrate the information through collaboration: •Produce a set of practical flow rules that stakeholders agree on•Create options with different levels of risk to the health of the assets
  30. 30. Huayuankou recommendation – low riskObjectives met Flow component Hydrologic criteria Mean annual Inter-annual Timing frequency/duration frequencyF1; M1 Cease to flow No cease to flow Continuous 100% of the time All yearB1; B2; B3, F2; WQ1, Low flow Dec ≥ 307 Continuous ≥ 75% of the time Dec - MayWQ2, WQ3, WQ4; Jan ≥ 280V3; M2; M5; F3; F4; Feb ≥ 321F11; F16 Mar ≥ 377 Apr ≥ 463 May ≥ 430F6; F7; F9; V1; B5; High flow Jun ≥ 434 Continuous ≥ 75% of the time Jun - NovM3; M4; F14 Jul ≥ 783 Aug ≥ 1,137 Sep ≥ 1,124 Oct ≥ 866 Nov ≥ 543V3; V4; F10 Low flow pulse ≥ 2,000 ≥ 1 per year / ≥4 in 5 years Nov - May 1 – 30 days; rates of rise and fall within natural rangeG1, G2, G3, G4, Bankfull 3,000 – 4,000 ≥ 1 per year / ~10 – ≥4 in 5 years Jun – SepWQ6; B6; B7; B8; 30 days duration;F12; F13; F5; F10 rates of rise and fall within natural range
  31. 31. Huayuankou recommendation – medium risk Objectives partly met Flow Hydrologic Mean annual Inter-annual Timing comp criteria frequency/duratio frequenc onen n y t F1; M1 Cease to No cease to flow Continuous 100% of the All year flow time B1; B2; B3, F2; WQ1, Low flow Dec ≥ 185 Continuous ≥ 75% of the Dec - May WQ2, WQ3, WQ4; Jan ≥ 174 time V3; M2; M5; F3; Feb ≥ 191 F4; F11; F16 Mar ≥ 229 Apr ≥ 284 May ≥ 263 F6; F7; F9; V1; B5; M3; High flow Jun ≥ 265 Continuous ≥ 75% of the Jun - Nov M4; F14 Jul ≥ 466 time Aug ≥ 754 Sep ≥ 744 Oct ≥ 534 Nov ≥ 335 G1, G2, G3, G4, WQ6; Bankfull 3,000 – 4,000 ≥ 1 per year / ~10 – 30 ≥4 in 5 years Jun – Sep B6; B7; B8; F12; days duration; F13; F5; F10 rates of rise and fall within natural range V3; V4; F10 Not provi ded
  32. 32. Model water resources availabilityWhat are the impacts on river users from the flow options?
  33. 33. Experience and recommendationsExperience --- Get new think, method from Australian expert ---The result close to the think of river manager, and can be implementRecommendation ---The e-flow assessment can be applied in other river in China
  34. 34. THANK YOU FOR YOUR ATTENTION

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