E-flows Yellow River (downstream) pilot

ACEDP Project: Environmental Flows in The Lower Yellow RiverJiang XiaohuiYRCC

Workshop, Beijing

2012 Feb 23

Contents

Background

General environmental flow assessment methodology

Brief description of work

Experience and recommendations

Sanmenxia

Xiaolangdi

Dam

N

Lake

City

Hydrological station

River

Lijin

Luokou

Aishan

Sunkou

Gaocun

Huayuankou

Dongping Lake

,

Kaifeng

Lijin

Zibo

Tai an

Dongping

Liaocheng

Qinyang

LuoyangSanmenxia Zhengzhou

Jinan

Survey

Site three

Study AreaBackground

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

In China there is a strong awareness of the need and importance of

environmental flows. Environmental flow assessments have been undertaken in

a number of rivers,

Environmental 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

General environmental flow assessment methodology

General environmental flow assessment

Brief description of work

Select sites and reaches

Field trip、 sample 、 workshop and literature search

Mengjinwetlands

Zhengzhouwetlands Kaifeng

wetlands

DongpingLake

Deltawetlands

River channelReaches

1

2

3

4

Identify ecological assets

• 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”).

River asset

Assets in the low Yellow River

• Fish species, e.g. Yellow River Carp• Wetland vegetation• Birds

• Spawning process• Sediment transport• Water quality

• Geomorphology

Develop conceptual models linking asset health and flow componentsGeomorphology, plants, fish, macroinvertebrates, water quality, birds…

Flow regime

Low flows Flow pulses High flows

Maintain depth of water in

refuge pools

Maintain adult fish population

Maintain larval andjuvenile habitat in river channel

Sediments from upstream and catchments increase. and DO decreases

Maintain backwater refuges and food resources for fish. Fish mortality increases.

Floods

Stimulate spawning

Food resources

Figure. The links between individual flow components and flow requirements for carp

July-OctoberAverage D > 0.8 m; V: 0.5 ms-1-1.2ms-1

FloodProvide new habitat and feeding opportunities for fish, but increased sediment and low DO may increase mortality

July-OctoberAverage D > 0.7 m; V: 0.3 ms-1-1ms-1

High flowProvide new habitat and feeding opportunities for fish

April - JuneD: 1-2 m at peak of flow pulse.Inundated beach area, and increase back water V<0.3 ms-1

Flow pulseStimulate spawning

Nov-Mar,April-June

Max D > 1.5 mV: 0.1-0.8 ms-1

Low flowMaintain sufficient water depth in pools for large bodied fish

TimingHydraulic criteriaFlow component

Objective

Table. Flow components and hydraulic criteria relevant to Yellow River Carp requirements. D = depth, V = velocity

Fish

No. Flow component Hydraulic/hydrologic criteriaF1 Cease-to-flow; Low flow Q ≥ YRCC warning standards of low flow emergency; maintain area‡

≥ critical depth* at pool crossings (specified each month)

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 V1F15 High flow and low flow See Vegetation objective V7F16 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

PlantsNo. Objective Flow component Hydraulic/hydrologic criteria

V1 Maintain submerged aquatic vegetation (e.g. Vallisneria, Potomageton and Myriophyllum spp.)

High flow Inundation to ≤ 1 m

V2 Maintain meadow vegetation High flow Inundation to ≤ 0.3 m

V3 Maintain Tamarix/Salix shrubland High flow, low flow and low flow pulse

100% of time shallow groundwater; Jul – Sep 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 flow pulse

100% of time shallow groundwater (at 1.5 – 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 grassland

High flow and low flow 100% of time waterlogging; varying inundation 0 – 0.5 m deep (1.5 m max.; 0.3 m mean) in summer

Birds

No. Objective Flow component Hydrologic/hydraulic criteria

B1 Foraging Low flows Expose CarexB2 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 mudflatsB4 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 creation

Bankfull An annual event that supplies enough sediment load to at least maintain delta area

B8 Summer-autumn habitat area

Bankfull An annual event to inundate backwaters and wetlands

Geomorphology

Geomorphologic-based objectives and flow requirements.

No. Objective Flow component

Hydrologic criteria Mean annual frequency/duration

Inter-annual frequency

Timing Reach Reference

G1 Scour and deposition processes to maintain dynamic and diverse habitats in the channel and connected floodplains

Bankfull 2,600 - 4,000 m3/s ≥ 1 per year / ≥ 1 day* duration

≥4 in 5 years Jun – Sep

Reach 1 Richards et al. (2002)

G2 Maintain channel capacity at 4,000 m3/s

Bankfull 2,600 - 4,000 m3/s ≥ 1 per year / ~10 – 30 days duration; rates of rise and fall within natural range

≥4 in 5 years Jun – Sep

All reaches

Liu et al. (2006)

G3 Seaward progradation of the delta

Bankfull Sediment load >3.45 × 108 tonnes at Lijin; event mean sediment concentration ≥ 35 kg/m3

≥ 1 per year ≥4 in 5 years Jun – Sep

Reach 4 Wang K et al. (2007); Wang et al. (2010)

G4 Flow into delta wetland channels to maintain channel form (and also provide freshwater and nutrients to the delta wetlands)

Bankfull >3,000 m3/s to allow gravity flow

≥ 1 per year / ≥ 10 days* days duration (or as required)

≥4 in 5 years Jun – Sep

Reach 4 Jiang Xiaohui (YRCC, pers. comm., November 2010)

* Based on expert opinion; refinement of this criterion will require investigation.

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

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

Key obj.

Obj. met Objectives description Flow component

A F1; M1 Prevent habitat loss through drying of shallow areas Cease to flow

B B1; B2; B3 Expose Carex and mudflats; shallow water over submerged aquatics Low flow

C F2 Maintain shallow habitats with moderate-high velocity for shallow water dwelling species and spawners during low flow periods

Low flow

D WQ1, WQ2, WQ3, WQ4

Dilute contaminants to Grade III standard Low flow and high flow

E V3; V4 Maintain Tamarix/Salix shrubland and woodland Low flow and high flowF M2; M5; F3; F4; F11;

F16Maintain reasonable area of habitat for most of the time for longitudinal connectivity, survival of large-bodied fish, maintenance of primary productivity in the estuary; and maintenance of DO levels in deep pools

Low flow and high flow

G F6; F7; F9 Provide suitable habitats for spawning, allow access of large bodied fish to backwater and wetland habitats; maintain downstream transport of semi-buoyant eggs within the water column; and sufficient depth in pools for large-bodied fish

High flow

H 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

maintain salinity gradient for anadromous fish spawning migrationHigh flow

K V3; V4; F10 Maintain Tamarix/Salix shrubland and woodland; and replenish/maintain water in river associated wetlands and backwaters

Low flow pulse

L F5; F10 Stimulate spawning, migration (anadromy and potadromy) and maintain habitat continuity between near-shore/estuarine and freshwater habitats to allow free upstream passage; and replenish/maintain water in river associated wetlands and backwaters

High flow pulse

M G1, G2, G3, G4, WQ6; B6; B7; B8; M7; M8; F12; F13;

Scour and deposition processes to maintain dynamic and diverse habitats in the channel and connected floodplains; maintain channel capacity at 4,000 m3/s; seaward 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

Bankfull

Hydrological and hydraulic modellingDetermine the characteristics of the flows (magnitude, duration,

frequency and timing) required to meet the objectives

Hydraulic model

• 1-dimension– Inexpensive– Cover a long reach– Cross-section average

• 2-dimension– Expensive

– Cover a short reach– Depth-averaged

Mean velocity V Depth D

Mean velocity VDepth D

Convert Hydraulic index to flow index

1-D HEC-RAS model output

2-D River2D model output

Velocity Flow direction

Mesh Depth

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

Establish flow rulesIntegrate 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

Huayuankou recommendation – low riskObjectives met Flow component Hydrologic criteria Mean annual

frequency/durationInter-annual frequency

Timing

F1; M1 Cease to flow No cease to flow Continuous 100% of the time All yearB1; B2; B3, F2; WQ1, WQ2, WQ3, WQ4; V3; M2; M5; F3; F4; F11; F16

Low flow Dec ≥ 307

Jan ≥ 280

Feb ≥ 321

Mar ≥ 377

Apr ≥ 463

May ≥ 430

Continuous ≥ 75% of the time Dec - May

F6; F7; F9; V1; B5; M3; M4; F14

High flow Jun ≥ 434

Jul ≥ 783

Aug ≥ 1,137

Sep ≥ 1,124

Oct ≥ 866

Nov ≥ 543

Continuous ≥ 75% of the time Jun - Nov

V3; V4; F10 Low flow pulse ≥ 2,000 ≥ 1 per year /1 – 30 days; rates of rise and fall within natural range

≥4 in 5 years Nov - May

G1, G2, G3, G4, WQ6; B6; B7; B8; F12; F13; F5; F10

Bankfull 3,000 – 4,000 ≥ 1 per year / ~10 – 30 days duration;rates of rise and fall within natural range

≥4 in 5 years Jun – Sep

Not provided

V3; V4; F10

Jun – Sep≥4 in 5 years≥ 1 per year / ~10 – 30 days duration;rates of rise and fall within natural range

3,000 – 4,000BankfullG1, G2, G3, G4, WQ6; B6; B7; B8; F12; F13; F5; F10

Jun - Nov≥ 75% of the time

ContinuousJun ≥ 265Jul ≥ 466Aug ≥ 754Sep ≥ 744Oct ≥ 534Nov ≥ 335

High flowF6; F7; F9; V1; B5; M3; M4; F14

Dec - May≥ 75% of the time

ContinuousDec ≥ 185Jan ≥ 174Feb ≥ 191Mar ≥ 229Apr ≥ 284May ≥ 263

Low flowB1; B2; B3, F2; WQ1, WQ2, WQ3, WQ4; V3; M2; M5; F3; F4; F11; F16

All year100% of the time

ContinuousNo cease to flowCease to flow

F1; M1

TimingInter-annual frequency

Mean annual frequency/duration

Hydrologic criteria

Flow component

Objectives partly met

Huayuankou recommendation – medium risk

Model water resources availabilityWhat are the impacts on river users from the flow options?

Experience and recommendations

Experience

--- Get new think, method from Australian expert

---The result close to the think of river manager, and can be implement

Recommendation

---The e-flow assessment can be applied in other river in China

THANK YOU FOR YOUR ATTENTION