River Training and Ecological
Restoration
Zhaoyin Wang
Professor, Tsinghua University
Chairman, Advisory Council of IRTCES
Chief Editor,International Journal of Sediment Research
Associate editor, IAHR, International Journal of Riverbasin
Management

Contents
1 Impacts on Ecology of River
Training Projects
2 Strategies of Ecological
Restoration and Improvement
3 Integrated stream restoration
with an artificial step-pool system

1 、 Impacts of River

Training and River Use
on Ecology

Impoundment of the Guanting Reservoir and numerous
dams on the Yongding River have caused 90% runoff
reduction. The water qulity has been reduced below 5grade of national standard响水堡延庆桥洋妫河石匣里桑干河八号桥

妫水大桥永定河

水河

The Yanghe River

The river bedWater Quality
1、Confluence of the Sanggan and the Yanghe Rivers: TN6.74 （below grade-5）;TP 0.17 (grade-3); NH4+ 0.11(gerade-1); CODMn3.49 (grade-2); F- 0.64 (grade-1);
2、No.8 Bridge: TN 10.37 (below grade-5）;TP 0.84 (grade5); NH4+ 3.34 (below grade-5); CODMn 5.42 (grade-3); F0.50 (grade-1);
3、Below the dam: TN 1.38 （grade-4）;TP 0.0082 (grade-1);
NH4+ 0.05 (grade-1); CODMn 2.04 (grade-2); F- 0.90(grade-1);•Only three species of macto-invertebrate are found in theRiver bed at No.8 bridge

摇蚊科Chironomidae
水蝇科Ephydridae
寡毛纲Oligochaeta

Artificial cutoff ofmeanders have
been
performed inmany river
training
projects, which
often results in
new fluvial
process andloss of habitats.

The cut-off ofmeanders andhardenedbanks in the
Rhein River
have caused
channelincision andecologicalproblems.
Humans haveto feed bed
load into theriver tomitigate theimpacts.

The Baozhusi Dam on theBailong River caused
frequent cut-off of flow in thedownstream reaches

Baozhusi dam on the Bailong River cut off the flow

Fengshuba dam on the East River causes artificial fluctuation ofdischarge which impact the ecosystem in the downstream reaches.

120

16Fengshuba
Reservoir

100

1080

S 860

640

212dn (Ind./m )

Sddnn

14

4
20

200
127

105
216
273
330
Distance to river mouth (km)

355

385

2.5

10Fengshuba
Reservoir

H2.0B

81.5

6B

H
1.0

40.5

20.00
127105216273
330
Distance to river mouth (km)

355

385

Richeness S and abundance dn, Shannon-Wiener Index, H, and the biocommunity index, B, as functions of distance to the river mouthMany mountain streams in south-west China are dried up due to water diversion forpower generation.(Baoxing River –Tributay of the Xiaojinchuan)

The Minjiang River is dried up because water is diverted from a low dam
in upper reach and transport through a tunnel to a power station in alower reach. There is no flow in the channel between the dam and thepower station.

Grand levees and channelization have resulted in separation ofhabitats and reduction of bio-diversity

Channelization and hardened banks resulted in enhancementof velocity and habitat loss

The complex Yangtze River-lakes habitat has been fragmented

140
Number120ofspecies
100River-linked lake
Seasonally river-linked lake
Isolated lake

80
6040
200
Floating-leavedplants

Emergent plants
Hygrophyte

Comparison ofbiodiversity
between riverlinked andisolated lakes inthe Yangtze Riverbasin

Floating plants

Submerged plants

Sum10090
Number80ofspecies
70

River-linked lake
Isolated lake60
50403020100
Oligochaeta

Mollusca

Aquatic insect

Other faunalspeciesSum2 、Restoration Strategies for stream
ecology
1.
2.
3.
4.
5.
6.
7.

Indicator species
Stability of habitat
Habitat diversity
Enhance the stability and diversity of habitat
Improving substrate and providing cover
Increase the area and connectivity of habitat
Control pollution below the purification capacityof streamEcologicalsystem

Criteria for Selecting Indicators
1) Sensitivity of the species to the environmental attributebeing evaluated.
2) Indicator accurately and precisely responds to themeasured effect.
3) Size of the species home range. If possible, the homerange should be larger than that of other species in theevaluation area. Threatened and endangered species,
are poor indicators because they are difficult to sample
adequately, often due to budget constraints.
4) Response uniformity in different geographic locations.
Response of an indicator species to an environmental
stress cannot be expected to be consistent acrossvarying geographic locations. If possible, the response
to a stress should be more uniform than that of otherspecies in different geographic locations.

Benthic Macroinvertebrates
Using benthic macroinvertebrates is advantageous
for the following reasons: 1) They are good
indicators of localized conditions. 2) They
integrate the effects of short-term environmental
variables. 3) Degraded conditions are easily
detected. 4) Sampling is relatively easy. 5) They
provide food for many fish of commercial orrecreational importance. 6) Macroinvertebrates are
generally abundant. 7) Many states already havebackground data.

Identification of species of invertebrates:

The invertebrates are examined（a） predator-dragonfly; (b) scraper-snails; (c) collector-filter - cadisfly; (d)蚬 (filter and collector); (e) shredder-沼梭)Fish
The advantages of using fish as bioindicators are
as follows: 1) They are good indicators of longterm effects and broad habitat conditions.2) Fishcommunities represent a variety of trophic(nutrient) levels. 3) Fish are at the top of theaquatic food chain and are consumed by humans.
4) Fish are relatively easy to identify. 5)Water
quality standards are often characterized in termsof fisheries. 6) Nearly one-third of theendangered vertebrate species and subspecies in
the United States are fish.

Fish samples

Cyprininae ~90% of Chinese fish are cyprinids“includes common carp 鲤科and goldfish”

2) Stabiltiy of habitat• Analyzing 300 samples from about
60 rivers concluded that
• Stability of aquatic habitat is themost important for stream ecology

Streams with stable bed have the best aquaticecology•

襀翅目

Plecoptera

短尾石蝇科Nemouridae•石蝇科Perlidae蜉蝣目Ephemeridae
扁蜉科Heptageniidae•小蜉科
Ephemerellidae

小蜉科
Ephemerellidae

小蜉科
Ephemerellidae

小裳蜉科
Leptophlebiidae

四节蜉科Baetidae毛翅目

Trichoptera
纹石蛾科
Hydropsychidae
长角石蛾科
Leptoceridae

短石蛾科
Brachycentridae

原石蛾科
Rhyacophilidae

小石蛾科Hydroptilidae

•

鞘翅目

Plecoptera
扁泥甲科
Psephenidae

•

腹足纲

溪泥甲科
Elmidae水龟甲科
Hydrophilidae

觿螺科Hydrobiidae

Gastropoda

摇蚊科

•

双翅目

Antocha属

花翅大蚊属
Hexotoma

Diptera•

端足目

Amphipoda钩虾科Gammaridae

Chironomidae

龙虱科

泥甲科

Dytiscidae

Dryopidae

Incised streams have less species
•

鞘翅目
沼梭科

Plecoptera•

溪泥甲科
ElmidaeHaliplidae

蜉蝣目

Ephemeridae

四节蜉科Baetidae

二尾蜉科小蜉科

Siphlonuridae

Ephemerellidae

小石蛾科

短石蛾科

Hydroptilidae

Brachycentridae

纹石蛾科
Hydropsychidae• 毛翅目
Trichoptera
水蝇科

蚋科

• 双翅目
DipteraEphydridae

Simuliidae
花翅大蚊属
Hextoma

水虻科
Stratiomyiidae

Aggradating streams have only few species• 蜻蜓目Odonata箭蜓科
Gomphidae•

大蜓科Cordulegasteridae

蜉蝣目

河花蜉科
细蜉科

Ephemeridae

Potamanthidae

Caenidae蜉蝣科
Ephemeridae• 双翅目
Diptera•

鞘翅目

Plecoptera

蠓科
Ceratopogonidae
摇蚊科Chironomidae

水龟甲科Hydrophilidae

Streams with strong sediment transportation have theworsest ecology

3). Habitat Diversity
Habitat has a definable carrying capacity, or suitability, tosupport or produce wildlife populations. The capacity
depends on the habitat diversity.
The physical conditions of stream habitat are mainly 1) thesubstrate; 2) water depth; and 3) flow velocity.
A habitat diversity index, HD, is proposed as follows

H D = N h N v ∑α ii

Table 10.3 Substrate diversity, α , values for different substrates (Wang et al., 2008)
Substrate

Flu id clay

Silt

Sand

Unstable sand,mud(0.02(0.2~2 mm)gravel, and silt

cobbles(D<0.02m~0.2bed(D＞200m)mm)(0.02~20 mm)

BouldersAquaticGravel

andgrass(2-200 mm)mm)

α6543

210

If a streambed has three parts with different substrates: boulders andcobbles, aquatic grasses, and fluid clay mud, and each of the threeparts is larger than 1/10 of the total stream area, the sum of the -values
for the stream is∑α i = 6 + 5 + 3 = 14i

If the streambed is covered by moving sand and gravel or the bed is very
unstable, the substrate diversity is zero.

3.0
2.0
H
1.0
0.0
02040
HD6080020406080

1612B

840HDFig. 10.36

Re lation between habitat diversity, HD , and Shannon-Weaver inde x, H(upper); and the relation

between habitat diversity, HD , and bio-commun ity inde x, B (lo wer)4)、Enhancing habitat diversity

Riprap weirs

Robber weirs on a mountain stream create stable
habitat for fishes

Deflectors – increase habitat diversityDeposition induced both upstream and downstream fromlimestone deflectors in a channel in England. One year
after the implementation vegetation has become
established on the deposit (Brookes).

Stabilize the banks with rootwad log

The protruding rootwads effectively reduce flow velocities at thetoe and increase habitat diversity.

5)、Improving substrate and providing
cover1.
2.
3.

Cobbles and high aquatic plant are the best substrate forfaunal community；Mud layer is also good.
Sand bed does not suitable for animals to live
Cover attracts many fish and invertebrates

Replacing the substrate with cobbles andgravel increased biodiversity

Field experiments by replacing the substrate withgravel and stones

Provide cover (increase habitat diversity)

Engineered logjams can restore riverine habitat and in somesituations provide effective bank protection

Artificial wetland (South Korea)

- Fish ladderFish ladder7)、Control pollution below the stream
purification capacity for pollutants andenhance the purification capacity

Aquatic plant species and macro-invertebrate
species in the Juma River
Plant：Potamogeton perfoliatus (穿叶眼子菜)、Chara fragilis Desv (轮藻)、Myriophylum verticillatumLinn (狐尾藻)、 Potamogeton
malaianus (竹叶眼子菜)、团藻
Benthic macro-invertebrates（ind/m2 for each species)
四节蜉科 Baetidae 191
萝卜螺属 Radix 111
蜉蝣科 Ephemeridae 90
Limnophilidae 70寡毛纲 Oligochaeta 58
扁蜉科 Heptageniidae 57
摇蚊科 Chironomidae 48
螨形目 Acariformes 29
无齿蚌属 Anodonta 16
细蜉科 Caenidae 14
蚬科 Corbiculidae 15其他蜉蝣目 Ephemeroptera 13
大蚊科 Tipulidae 8
方格短沟蜷 S.cancellata 5
龙虱科 Dytiscidae 4双翅目Diptera 4
蠓科 Ceratopogonidae 4
箭蜓科 Gomphidae 3
小裳蜉Leptophlebiidae 2
蛭纲 Hirudinea
2
纹石蛾科 Hydropsychidae 1
半翅目 Hemiptera 1
扁形动物 Platyhelminthes 1

Purification capacity of stream per lengthTNTP
Reac（mg/L （mg/Lh））lenth（km）

Purification
capacity per
length for TN(mg/L·km）

Purification
capacity perlenth for TP(mg/L·km）

L1-2

0.15

0.001120.0750.00055

L2-3

0.23

0.00023.5

0.06570.000057

L1-3

0.38

0.00135.5

0.06910.000234

3、Integrated stream restoration
with an artificial step-poolsystemThe Diaoga River isan incised mountainstream and there isno naturally
developed step-poolsystemAquatic ecology is bad

Collision in two phase debris flows resulted in many
Stone spheres

Measurement of bed load transportationMacro-benthic invertebrate
sampling in the Diaoga Ravine

Make the stones overlapping and interlocking like tilesCreate habitats for aquatic biocommunity

1000
2

water surface area (m )with articificial step-pools
800

without artificial step-pools

600
400
200
00.00.5

1.0

1.5

2.0

3

discharge (m /s)

Water surface area as a function of discharge before and after theartificial step-pools

Variation of longitudinal profile of experimental reach
1845
July-1June-18

elevation(m)

1843
1841
1839
1837

E x per im e

1835
1833
050

reac
h

100

150

200

distance downstream (m)1845elevation (m)ntalAugust-9
June-18

1843
1841
1839
1837
1835
1833
020

406080100120

distance downstream (m)140160180200Main species before the artificial step-pools
Gammaridae
Heptageniidae

Lymnaeidae

Ceratopsyche sp.

Newly appeared species
Gaenis spWith
StepPools

Simuliidae

Empididae,Tabanus
Perlidae
Limnephilidae

Table 2 variation of taxa richness and diversity before and after
artificial step-pool system

NaturalchannelWith
artificial
steppools

NumberTaxa
Samplinrichnes density
g date(ind/ms2)

Dominant species(number density of the individual invertebrate
per m2)13-Jun1761.5

Hydropsychidae (17); Baetidae (9); Haliplidae,Haliplus sp (7)28-Jun39

881.5

Baetidae (492); Simuliidae (150); Tipulidae,
Antocha (65)612.8

Baetidae, Baetis (330); Baetidae, Baetiella sp.
(70); Chironomidae sp1 (57); Chironomidae sp2(48)

11-Sep28

The stream is now
green and thelandscape is greatly
improvedCreate beautiful landscapeConclusions
1. River training projects impact the stream ecology greatly.
2. 河流治理应从“以人为本”改为 “以河为本” The focal
point of river training projects should shift from human’s
demands to river’s.
3. River management should follow the principles: I –Extending the duration of river water on the continent; II–Controlling erosion and reducing sediment transportation;
III – Increasing diversity and connectivity of habitats;and IV – Restoring natural landscapes
4. Biodiversity is proportional to habitat stability anddiversity.
5. Artificial step-pool system is the best strategy for stream
stabilization and ecology improvement

Thank you !