the radar-graphic method for evaluation of the ......eco-environment. the requirement of landscape...
TRANSCRIPT
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The SIJ Transactions on Advances in Space Research & Earth Exploration (ASREE), Vol. 1, No. 2, November-December 2013
ISSN: 2347 – 6087 © 2013 | Published by The Standard International Journals (The SIJ) 43
Abstract—Over the past decade in Taiwan, ecological engineering methods acted principally in river
remediation and slope protection. In order to examine the effectiveness of stream restoration, the Index of
Stream Restoration Guidance (ISRG) and Radar-Graphic Method (RGM) were used to describe the overall
stream condition. Six criteria must be considered in the evaluation of a stream’s ecological environment: water
quality, habitat quality, eco-hydrology, flood prevention, aesthetic and recreational demand, and bank stability.
Using the assessment results in the Jilong River overall improvement project, a river located in northern
Taiwan, five conclusions were drawn: (1) ISRG scores on stream’s ecological environment and biological
performance are higher at the upstream than at the middle and downstream; (2) good ecological performances
were observed under the condition of a gentle revetment and wider green belt; (3) type of revetment which are
porous and permeable will create better biodiversity; (4) the ecological performance at the middle and
downstream depends on the human disturbance; (5) the proposed methodology establishes a quantitative
assessment tool and provides a guide to planning and implementing stream restoration projects.
Keywords—Biodiversity; Index of Stream Condition; Jilong River; Radar-Graphic Method; Stream Ecological
Engineering; Stream Restoration.
Abbreviations—Ephemeroptera, Plecoptera, Trichopetera (EPT); Indexes of Biological Integrity (IBI); Index
of Stream Condition (ISC); Index of Stream Restoration Guidance (ISRG); Family-level Biotic Index (FBI);
Radar-Graphic Method (RGM); Rapid Bioassessment Protocol III (RBP III).
I. INTRODUCTION
UE to the increase of ecological awareness, Taiwan
started to seek advanced technology from other
countries in order to modify traditional civil
engineering practices which prioritized development and
human demands. In the late 1990s, a field research associated
with environment beautification was launched. The new
philosophy of ecological engineering began to attract
academic institutes’ attention gradually. Government also
initiated all sorts of funding for the purposes of a) the
possible limitation of applying it in Taiwan, and b)
establishing localized applicable methods in river
reconstruction. Slightly after the water resources related
agencies’ action, this new trend started to affect soil
conservation practices by introducing river bank stabilization
methods. Followed by valuing the advantage over water
quality control, ecological engineering also contributes to
Taiwan’s environmental engineering since 2003. This
abstract is a brief introduction to the subject of ecological
engineering method, which is a whole new concept in the
field of civil engineering. The advantages of using the
ecological engineering method are not only to satisfy the
demand of safety (i.e. natural hazards control) but also that of
protecting ecosystem and landscape aesthetic.
In Taiwan, typhoons are very common during the
summer and bring huge amount of precipitation with them.
The development and management works of the rivers in
Taiwan were, in the early days, primarily focused on water
control for hydraulic facilities, but also considered overall
eco-environment. The requirement of landscape creation and
eco-environment protection from people are on the rise with
the recent ecological protection concepts. For this reason,
Taiwan Water Resource Agency executed the “Jilong River
Overall Master Plan (Earlier Plan)” from 2002 to 2005
[National Taipei University of Technology, 2012] to reduce
D
*Assistant Professor, Department of Civil Engineering, National Taipei University of Technology, Taipei, TAIWAN, ROC.
E-Mail: [email protected]
**Professor, Department of Civil Engineering, National Taipei University of Technology, Taipei, TAIWAN, ROC. E-Mail: [email protected]
***Chief Secretary, Water Resources Department, New Taipei City Government, New Taipei City, TAIWAN, ROC.
E-Mail: [email protected]
****Master, Department of Civil Engineering, National Taipei University of Technology, Taipei, TAIWAN, ROC.
E-Mail: [email protected]
Chia-Chun HO*, Jen-Yang LIN**, Tsung-Ming YANG*** & Kuan-Han CHOU****
The Radar-Graphic Method for
Evaluation of the Effectiveness of
Stream Ecological Engineering
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The SIJ Transactions on Advances in Space Research & Earth Exploration (ASREE), Vol. 1, No. 2, November-December 2013
ISSN: 2347 – 6087 © 2013 | Published by The Standard International Journals (The SIJ) 44
the risk of flooding and improve the environment. Figure 1
below shows the failure of the Jilong River revetment which
suffered a serious flooding in 2001. Because of this,
ecological engineering methods were adopted to rebuild the
revetment. Figure 2 shows the current status of this revetment
using gabion method and vegetation blanket. In order to
understand the effectiveness of revetment while using
ecological engineering method, the ecological investigation
and basis of construction work of the Jilong River was
divided between the upstream, midstream and downstream.
The project was completed over several years, mainly due to
the fact that the river ecological data had to satisfy the design
and guidelines of an eco-environment adapted for the river.
Thus, the investigation of the before and after conditions
were necessary. After reviewing the effect of the environment
due to the changes brought by the master plan, reinforcement
strategies and suggestions should be proposed as to reach
higher ecological environment influence.
(a) Upstream (b) Midstream
Figure 1: A Failure Cases of Revetment
(a) Upstream (b) Midstream
Figure 2: The Current Status after Construction
II. THE ASSESSMENT OF THE STREAM
CONDITION
The effectiveness of the stream remediation mostly focused
on the hydraulic structure safety. It is rarely from an
ecological point of view that we examine the effectiveness.
However, the performance of the biological environment
should be included in the assessment of stream remediation
projects. Researchers have published several studies on the
biotic index.
2.1. Biological Index
Previous studies proposed a different index for bio-
environment. Karr (1991) adopted fish to be a bio-indicator
and proposed the Indexes of Biological Integrity (IBI).
Depending on the IBI score, the biological condition can be
classified within four categories, as shown in Table 1.
Table 1: The Biological Condition Category and Score Range of IBI
Biological Condition Category Score Range
Non-impaired 30-39
Slightly impaired 21-29
Moderately impaired 11-20
Severely impaired 0-10
Base on the water quality and water pollution resistance
of fish, a Family-level Biotic Index (FBI) was proposed by
Hilsenhoff (1998). Table 2 shows the FBI score range.
Table 2: Water Quality and Score Range of FBI
Water Quality Score Range Water Quality Score Range
Excellent 0.00-3.75 Fairly Poor 5.76-6.50
Very Good 3.76-4.25 Poor 6.51-7.25
Good 4.26-5.00 Very Poor 7.26-10.00
Fair 5.01-5.75
Plafkin et al., (1989) adopted seven bio-indexes to
evaluate water quality and stream environment, and therefore
the Rapid Bio-assessment Protocol III (RBP III) was advised.
The indexes include taxa richness, Hilsenhoff biotic index,
ratio of scrapers/fil. collectors, ratio of EPT (Ephemeroptera,
Plecoptera, Trichopetera) and chironomid abundances,
contribution of dominant taxon (%), EPT index, and
community loss index. Table 3 shows the biological
condition scoring criteria.
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The SIJ Transactions on Advances in Space Research & Earth Exploration (ASREE), Vol. 1, No. 2, November-December 2013
ISSN: 2347 – 6087 © 2013 | Published by The Standard International Journals (The SIJ) 45
Table 3: Biological Condition Scoring Criteria of RBP III
Water Quality Biological Condition Scoring Criteria
6 4 2 0
Taxa richness >80% 60%-80% 40%-60% 85% 70%-85% 50%-70% 50% 35%-50% 20%-35% 75% 50%-75% 25%-50% 90% 80%-90% 70%-80%
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The SIJ Transactions on Advances in Space Research & Earth Exploration (ASREE), Vol. 1, No. 2, November-December 2013
ISSN: 2347 – 6087 © 2013 | Published by The Standard International Journals (The SIJ) 46
Figure 3: Assessment of Stream Condition using the ISC [Ladson et
al., 1999]
2.3. Index of Stream Restoration Guidance (ISRG)
Base on the Index of Stream Condition (ISC) and
incorporation factors unique to Taiwan, Lin et al., (2005)
proposed the Index of Stream Restoration Guidance (ISRG)
and developed six indices for evaluating stream restoration
projects using the ecological engineering methods. These
indices include considerations for stream ecological
environment, water quality and habitat, eco-hydrology, flood
prevention, aesthetics and recreation demands, and bank
stability requirements. The indicators and score within those
six indices are shown in Table 5. According to the score of
those six indices, the Radar-Graphic Method (RGM) was
used to evaluate the effectiveness of stream ecological
engineering. Figure 4 shows the best performance of RGM on
stream restoration. Three of the indices scores (flood
prevention, aesthetics and recreation demands, and bank
stability requirements) are very low. It indicates not only that
the hydraulic design for this stream is satisfactory but also
that the effectiveness of ecological environment is superior.
Table 5: Indicators used in the Index of Stream Restoration Guidance [Lin et al., 2005]
Sub-Index Indicators within Sub-Index Score
(X) Conversion Coeff. Sub-Index Score
A. Stream ecological environment
Width of streamside zone 0-4
(X)(10/10) 0-10 Longitudinal continuity 0-4
Cover of vegetation 0-2
B. Bank stability requirements
Geology of river bank
0-4 (X)(10/4) 0-10 Erosion of river bank
Erosion of bank toe
C. Water quality and habitat River pollution index 0-16
(X)(10/20) 0-10 Fish species and populations 0-4
D. Flood prevention
Protected targets
Flood history
Flood damages
Investment cost
0-10 (X)(10/10) 0-10
E. Eco-hydrology
Ecological instream flows 0-10
(X)(10/18) 0-10 Aquatic habitat environment 0-4
Bed stability 0-4
F. Aesthetics and recreation demands
Landscape aesthetics
Promenade recreation
Environmental education
Irrigation
0-10 (X)(10/10) 0-10
Figure 4: Illustration of the Best Performance of RGM on Stream
Restoration
This paper is a case study using ISRG and furthermore
the ecological environment investigation was carried out in
great detail to confirm the feasibility of RGM.
III. THE EVALUATION RESULTS OF JILONG
RIVER USING RGM
“Jilong River Overall Master Plan (Earlier Plan)” was
proposed after permission of the Taiwan Executive Yuan in
May, 2002. The 3 year plan was executed between 2002 to
2005 and received a funding of $12 billion US dollars. The
plan has now been completed for 7 years and has undergone a
Indicator
RatingCorresponding reference category
Example values:
pH range
4 Very close to reference state 6.5-7.5
3 Minor modification from reference state 6.0-
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The SIJ Transactions on Advances in Space Research & Earth Exploration (ASREE), Vol. 1, No. 2, November-December 2013
ISSN: 2347 – 6087 © 2013 | Published by The Standard International Journals (The SIJ) 47
number of typhoons. In order to know the performance of this
plan, RGM was used to evaluate of the effectiveness of
stream ecological engineering in this study. Further analysis
of significant improvement master methods has been
performed to provide as criterion for further master plan of
other reaches. Assessment of non-significant master methods
has been executed and reinforcement strategies have been
proposed in this study. In order to understand the
effectiveness of stream ecological engineering, three survey
stations were investigated which were located upstream,
midstream and downstream. According to the six sub-index
of the ISRG, to calculate their scores and graph the RGMs.
3.1. Upstream of Jilong River
The upstream channel of Jilong River, with a length of
11.7km and a mean height of 12.6m, was improved using
gabion, stone-paved and geo-grid reinforced revetment. River
investigation of current status and the change of environment
before and after master plan have been executed to review the
influence and improvement of the master plan. The
assessment results at the upstream are shown on Table 6.
Table 6: The Assessment Results of ISRG at the Upstream of Jilong River
Sub-index Indicators within sub-index Point
(X) Conversion Coeff. Sub-Index Score
A. Stream ecological environment
Width of streamside zone 3
7(10/10) 7.0 Longitudinal continuity 3
Cover of vegetation 1
B. Bank stability requirements
Geology of river bank
1 1(10/4) 2.5 Erosion of river bank
Erosion of bank toe
C. Water quality and habitat River pollution index 12
16(10/20) 8.0 Fish species and populations 4
D. Flood prevention
Protected targets
Flood history
Flood damages
Investment cost
1.8 1.8(10/10) 1.8
E. Eco-hydrology
Ecological instream flows 10
16(10/18) 8.9 Aquatic habitat environment 3
Bed stability 3
F. Aesthetics and recreation demands
Landscape aesthetics
Promenade recreation
Environmental education
Irrigation
3 3(10/10) 3.0
Radar-Graphic Method (RGM)
A. Stream Ecological Environment
The sub-index of stream ecological environment includes
width of streamside zone, longitudinal continuity and cover
of vegetation. Figure 5 shows the current situation of stream
ecological environment. The width of the streamside zone is
127.5 meters and it is 2.56 times the breadth of the river’s
active channel. This area shows a good performance from the
vegetation except the zone under the bridge, furthermore the
vegetation cover rate at the upstream is 78% done by
shrubbery and grass. The comprehensive improvement
observed in result to our field investigation ensued in a sub-
index score of 7.0 on stream ecological environment.
Figure 5: The Current Situation of Stream Ecological Environment
at the Upstream of Jilong River [Ho et al., 2013]
02468
10A
B
C
D
E
F
A: Stream ecological environment
B:Bank stability requirements
C:Water quality and habitat
D:Flood prevention
E:Eco-hydrology
F:Aesthetics and recreation demands
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ISSN: 2347 – 6087 © 2013 | Published by The Standard International Journals (The SIJ) 48
B. Bank Stability Requirements
In order to know the river bank stability and its erosion
situation, the bathymetry survey of each cross-section were
employed in this study. Choosing one of the cross-sections at
the upstream and comparing its bathymetry results between
the 2006 and 2011 survey (see Figure 6), we can notice a
slight difference in the improvement works completed after 1
year (2006) and 6 years (2011) of Section K-70. We can
therefore say that the bank stability requirement is very low
and scored 1.0 point; hence the sub-index score is 2.5.
Figure 6: The Results of the Bathymetry Survey in 2006 and 2011.
(Section K-70)
C. Water Quality and Habitat
There are 5 water quality monitoring stations at the upstream
of Jilong River. Their evalutation of the average value for
total phosphorus in 2011 is 0.005 mg/L, turbidity is 8.97
NTU, conductivity is 182 mho/ cm-25°C, and pH is 7.8. According to the scoring criteria of ISRG, the score for the
river pollution index is 12 points.
Moreover, the aquatic life in Jilong River was
investigated from 2010 to 2012 and recorded 14 species of
fish at the upstream. All of the fish are native species
including the Varicorhinus barbatulus, Acrossocheilus
paradoxus, Zacco platypus, Formosania lacustre, and so on
(Figure 7). Hence, in accordance with the scoring criteria of
ISRG, the score of fish species and populations is 4 points.
Consequently, the sub-index score of water quality and
habitat is 8.0.
(a) Varicorhinus barbatulus (b) Acrossocheilus paradoxus
(c) Zacco platypus (d) Formosania lacustr
Figure 7: The Native Fishes at the Upstream of Jilong River
D. Flood Prevention
The land purpose surrounding the Jilong River’s upstream is
predominantly based on agriculture and forestry. The
protected targets in potential flooding regions consist of only
some of the constructions such as roads, bridges, and
buildings. The heavy rainfalls brought by typhoon NARI in
September 2001 had not caused significant damages to roads
and properties at this area. In view of the above, the sub-
index score of flood prevention is 1.8.
E. Eco-Hydrology
The score for the ecological instream flows is 10 because the
flow rate throughout the year has been consistently greater
than 0.5 cms, even without lateral construction in the river
channel at the upstream. It is a near ideal aquatic habitat with
numerous pieces of coarse wood debris from indigenous
species and so scored 3 points. Furthermore, it has good
vegetative cover, some minor isolated erosion, and no
continuous damage to the bank structure or vegetation itself,
bringing the indicator for the bed stability to 3 points. Finally,
when calculating the sub-index for the eco-hydrology, we get
a score of 8.9.
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ISSN: 2347 – 6087 © 2013 | Published by The Standard International Journals (The SIJ) 49
F. Aesthetics and Recreation Demands
The upstream of Jilong River has some small-scale farms by
the streamside which makes use of stream water for
irrigation. Therefore, the sub-index score of aesthetics and
recreation demands is 3.0.
The chart of Radar-Graphic Method is also show in
Table 6. It indicates the steep riverbank caused by the poor
performance of vegetation at the upstream; hence the score of
sub-index A is not high. The good water quality and flow rate
provide an excellent biological environment and
consequently got the high score on sub-index C and E.
Moreover, the riverbank is located on the bedrock, and
therefore does not produce the erosion of bank toe. For this
reason, the score on bank stability requirement is low.
Briefly, the ecological engineering method achieved
remarkable improvement in the upstream and the shape of the
RGM presents a triangle arrow.
3.2. Midstream of Jilong River
The midstream channel of Jilong River has a length of
19.9km and a mean height of 10.2m. Besides gabion, stone-
paved and geo-grid reinforced revetment, the revetment
improvement works used a number of concrete banks to
protect the residents living by the river side as well as spread
vegetation blanket on the surface of concrete banks.
Investigation of the river’s current status and the before and
after environment change of the master plan have been
executed to review the influence and improvement of the
master plan. The assessment results at the midstream are
shown on Table 7.
Table 7: The Assessment Results of ISRG at the Midstream of Jilong River
Sub-index Indicators within sub-index Point
(X)
Conversion
Coeff.
Sub-Index
Score
A. Stream ecological environment
Width of streamside zone 4
9(10/10) 9.0 Longitudinal continuity 4
Cover of vegetation 1
B. Bank stability requirements
Geology of river bank
1 1(10/4) 2.5 Erosion of river bank
Erosion of bank toe
C. Water quality and habitat
River pollution index 11
14(10/20) 7.0 Fish species and populations
3
D. Flood prevention
Protected targets
Flood history
Flood damages
Investment cost
4.0 4(10/10) 4.0
E. Eco-hydrology
Ecological instream flows 8
12(10/18) 6.7 Aquatic habitat
environment 2
Bed stability 2
F. Aesthetics and recreation demands
Landscape aesthetics
Promenade recreation
Environmental education
Irrigation
7.5 7.5(10/10) 7.5
Radar-Graphic Method (RGM)
A. Stream Ecological Environment
Figure 8 shows the current situation of stream ecological
environment. The width of the streamside zone is 136.7m and
it is 3.12 times the breadth of the river’s active channel.
Because of the wide and gentle beach, the vegetation shows a
nice performance in this area. Furthermore, the vegetation
cover rate at the midstream is 89% done by shrubbery and
grass. The comprehensive improvement observed in result to
our field investigation ensued in a sub-index score of 9.0 on
stream ecological environment.
02468
10A
B
C
D
E
F
A: Stream ecological environment
B:Bank stability requirements
C:Water quality and habitat
D:Flood prevention
E:Eco-hydrology
F:Aesthetics and recreation demands
A: Stream ecological environment
B:Bank stability requirements
C:Water quality and habitat
D:Flood prevention
E:Eco-hydrology
F:Aesthetics and recreation demands
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ISSN: 2347 – 6087 © 2013 | Published by The Standard International Journals (The SIJ) 50
Figure 8: The Current Situation of Stream Ecological Environment
at the Midstream of Jilong River [Ho et al., 2013]
B. Bank Stability Requirements
Figure 9 shows a comparison of the results of the bathymetry
survey performed in 2006 and 2011. Some minor isolated
erosion cases could be noticed on the river bed from the
improvement works completed after 1 year (2006) and 6
years (2011) of the Section K-88. However, the surface of the
river bank and its toe are still stable as well as no
displacement happened from 2006 to 2011. So the sub-index
of bank stability requirement score is 2.5.
Figure 9: The Results of the Bathymetry Survey in 2006 and 2011.
(Section K-88)
C. Water Quality and Habitat
A total of 4 water quality monitoring stations were
established at the midstream of Jilong River. Their evaluation
of the average value for total phosphorus in 2011 is 0.0143
mg/L, turbidity is 18.54 NTU, conductivity is 325 mho/cm-
25°C, and pH is 7.5. According to the scoring criteria of
ISRG, the score of river pollution index is 11 points.
Moreover, the aquatic life in Jilong River was
investigated from 2010 to 2012 and recorded 19 species of
fish at the midstream. At this particular segment of the river,
not only native fishes were found but also exotic ones such as
Cyprinus carpip, Oreochromis sp., Channa striata,
Hypostomus placostomus, and so on (Figure 10). Hence, in
accordance with the scoring criteria of ISRG, the score of fish
species and populations is 3 points. Consequently, the sub-
index score of water quality and habitat is 7.0.
(a) Cyprinus carpip (b) Oreochromis sp
(c) Channa striata (d) Hypostomus placostomus
Figure 10: The Exotic Fishes at the Midstream of Jilong River
D. Flood Prevention
The land purpose of Jilong River’s midstream is
predominantly based on agriculture and small town. The
protected targets in potential flooding regions include roads,
bridges, and buildings. Hence, the sub-index score of flood
prevention is 4.0.
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ISSN: 2347 – 6087 © 2013 | Published by The Standard International Journals (The SIJ) 51
E. Eco-hydrology
The score of ecological instream flows is 8 due to the flow
rate throughout the year being greater than 0.5 cms, achieved
with some lateral construction in the river channel. It is a
moderate variation from an ideal aquatic habitat with
moderate visible pieces of coarse wood debris from
indigenous species, therefore the scored attributed if of 2
points. Furthermore, as the banks were held by discontinuous
vegetation and showed a generally stable toe, the indicator of
bed stability received 2 points. Finally, the calculated sub-
index score of eco-hydrology is 6.7.
F. Aesthetics and Recreation Demands
The riverside of the midstream has a number of bicycle paths,
parks, and river-accessible spaces. Therefore, the sub-index
score of aesthetics and recreation demands is 7.5.
The chart of Radar-Graphic Method is also show in
Table 7. The current situation displays a nice result on
vegetation of gabion revetment wall and provides a good
biological habitat environment. Thus the score of sub-index
A, C and F are high; nevertheless, they are lower than the
score observed at the upstream. That can be explained by the
bad results in water quality and a higher human disturbance
than at the upstream. In addition, the aesthetics and recreation
demands are higher than at the upstream.
3.3. Downstream of Jilong River
The downstream channel of Jilong River has a length of
15.2km and a mean height of 8.7m. Because it is adjacent to a
dense residential area, a large number of concrete banks were
adopted in its improvement project. In order to build a good
ecological environment, vegetation blankets were spread on
the surface of some concrete banks. . Investigation of the
river’s current status and the before and after environment
change of the master plan have been executed to review the
influence and improvement of the master plan. The
assessment results at the downstream are shown on Table 8.
Table 8: The Assessment Results of ISRG at the Downstream of Jilong River
Sub-index Indicators within sub-index Point
(X) Conversion Coeff. Sub-Index Score
A. Stream ecological environment
Width of streamside zone 2
5(10/10) 5.0 Longitudinal continuity 2
Cover of vegetation 1
B. Bank stability requirements
Geology of river bank
1.8 1.8(10/4) 4.5 Erosion of river bank
Erosion of bank toe
C. Water quality and habitat River pollution index 10
12(10/20) 6.0 Fish species and populations 2
D. Flood prevention
Protected targets
Flood history
Flood damages
Investment cost
8.0 8(10/10) 8.0
E. Eco-hydrology
Ecological instream flows 7
10(10/18) 5.6 Aquatic habitat environment 2
Bed stability 1
F. Aesthetics and recreation
demands
Landscape aesthetics
Promenade recreation
Environmental education
Irrigation
8.5 8.5(10/10) 8.5
Radar-Graphic Method (RGM)
A. Stream Ecological Environment
Figure 11 shows the current situation of the downstream
ecological environment. The downstream width of the
streamside zone is 102.3m and it is 0.67 times the breadth of
the river’s active channel. In this region, the concrete banks
hold a discontinuous vegetation and has a cover rate of 63%
achieved by shrubbery and grass. The comprehensive
02468
10A
B
C
D
E
F
A: Stream ecological environment
B:Bank stability requirements
C:Water quality and habitat
D:Flood prevention
E:Eco-hydrology
F:Aesthetics and recreation demands
A: Stream ecological environment
B:Bank stability requirements
C:Water quality and habitat
D:Flood prevention
E:Eco-hydrology
F:Aesthetics and recreation demands
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ISSN: 2347 – 6087 © 2013 | Published by The Standard International Journals (The SIJ) 52
improvement observed in result to our field investigation
ensued in a sub-index score of 5.0 on stream ecological
environment.
Figure 11: The Current Situation of Stream Ecological Environment
at the Downstream of Jilong River [Ho et al., 2013]
B. Bank Stability Requirements
Figure 12 shows a comparison of the results of the
bathymetry survey performed in 2006 and 2011. An obvious
erosion of the river bed of Section K-101 can be noticed from
the improvement works completed after 1 year (2006) and 6
years (2011); moreover, some damage to the bank structure
and vegetation can be clearly noticed. The situation of this
region is moderate bed degradation and therefore the sub-
index of bank stability requirement score is 4.5.
Figure 12: The Results of the Bathymetry Survey in 2006 and 2011.
(Section K-101)
C. Water Quality and Habitat
A total of 4 water quality monitoring stations were placed in
the downstream of Jilong River and their monitored average
value for total phosphorus in 2011 is 0.0265 mg/L, turbidity
is 27.9 NTU, conductivity is 383 mho/cm-25°C, and pH is
7.6. According to the scoring criteria of ISRG, the score of
river pollution index is 10 points.
Moreover, the aquatic life in Jilong River was
investigated between 2010 and 2012 and recorded 22 species
of fish at the downstream. Most of the exotic fishes and the
peripheral division freshwater fishes in midstream were also
reported to be living in the downstream, such as Mugil
cephalus, Nematalosa nasus, Awaous melanocephalus,
Acanthopagrus schlegeli, and so on (Figure 13). Hence, in
accordance with the scoring criteria of ISRG, the score of fish
species and populations is 2 points. Consequently, the sub-
index score of water quality and habitat is 6.0.
(a) Mugil cephalus (b) Nematalosa nasus
(c) Awaous melanocephalus (d) Acanthopagrus schlegeli
Figure 13: The Peripheral Division Freshwater Fishes at the Downstream of Jilong River
D. Flood Prevention
The land surrounding the Jilong River’s downstream is
predominantly urban. It is a densely inhabited district and the
protected targets in potential flooding regions include roads,
bridges, and buildings. This region also is an important
business area. Heavy rainfalls brought by typhoon NARI in
September 2001 caused serious damages to the roads and
properties at this area. Hence, the sub-index score of flood
prevention is 8.0.
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ISSN: 2347 – 6087 © 2013 | Published by The Standard International Journals (The SIJ) 53
E. Eco-hydrology
The score of ecological instream flows is 8 due to the flow
rate throughout the year being greater than 0.5 cms, achieved
with some lateral construction in the river channel. It is a
moderate variation from an ideal aquatic habitat with
moderate visible pieces of coarse wood debris from
indigenous species, therefore the scored attributed if of 2
points. Furthermore, as the banks were held by discontinuous
vegetation and showed a generally stable toe, the indicator of
bed stability received 1 point. Finally, the calculated sub-
index score of eco-hydrology is 5.6.
F. Aesthetics and Recreation Demands
The downstream riverside has a number of bicycle paths,
parks, playground, tennis court, and river-accessible spaces.
Therefore, the sub-index score of aesthetics and recreation
demands is 8.5.
The shape of RGM for the downstream section (Table 8)
is different to the results shown at the upstream and
midstream sections. Because of the dense human habitation
surrounding the downstream, the flood prevention, aesthetics
and recreation demands are more important than for the
upstream and midstream. This results in a higher score on
sub-index D and sub-index F. A concrete revetment was used
to protect the inhabitants living adjacently to the river. Due to
the steep and smooth surface of the concrete revetment, a
poor plant growth was observed. These conditions paired
with some serious human disturbance results in a poor
biological performance in the downstream and consequently
the score of sub-index A, C and E was lower than for the
upstream and midstream.
IV. CONCLUSIONS
The shape of RGM is represented in the form of a
triangle arrow for the upstream. It indicates the
excellent effectiveness of stream ecological
engineering. Moreover, the scores of ISRG for the
stream ecological environment and biological
performance are higher than for the middle and
downstream.
For the downstream, high quality and hard
protective works had to be used to ensure the safety
of the dense human habitation and therefore induce a
poor performance of the ecology environment.
Good ecological performances were observed under
the condition of gentle revetment and wider green
belt at the midstream.
Revetment including porous and permeable
functions will create better biodiversity, such as
gabion, stone-paved and geo-grid reinforced
revetment.
The ecological performance at the middle and
downstream was greatly affected by human
disturbance.
ISRG and RGM establish a quantitative assessment
tool and provide a guide on how to plan and
implement stream restoration projects.
REFERENCES
[1] National Taipei University of Technology (2012), “Closure Report of Investigation and Evaluation after Jilong River
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[2] J.R. Karr (1991), “Biological Integrity: A Long-Neglected Aspect of Water Resource Management”, Ecological
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[3] W.L. Hilsenhoff (1998), “A Modification of the Biotic Index of Organic Stream Pollution to Remedy Problems and Permit its
Use throughout the Year”, Great Lakes Entomologist, Vol. 31,
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[4] J.L. Plafkin, M.T. Barbour, K.D. Porter, S.K. Gross & R.M. Hughes (1989), “Rapid Bioassessment Protocols for Use in
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[5] A.R. Ladson & L.J. White (1999), “An Index of Stream Condition: Reference Manual”, Department of Natural
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[6] A.R. Ladson, L.J. White, J.A. Doolan, B.L. Finlayson, B.T. Hart, P.S. Lake & J.W. Tilleard (1999), “Development and
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[7] J.Y. Lin, F.C. Yu & M.S. Wu (2005), “Using the Radar-Graphic Method as a Guide for Stream Ecological Engineering
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[8] C.C. Ho, J.Y. Lin & K.H. Chou (2013), “An Evaluation of the Effectiveness of Stream Ecological Engineering using the
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Chia-Chun HO Education: Ph. D., Hydrology and
Environment, Joseph Fourier University,
France
Position: Assistant Professor, Department of
Civil Engineering, National Taipei
University of Technology
Research interest: Environmental and
Ecological Engineering, Geotechnical
Engineering, Geosynthetics Application, Erosion Behaviour of
Revetments
Number of papers published: 8
Number of conferences/seminars attended: 26
Jen-Yang LIN
Education: Dr.-Ing., Civil Engineering,
Kassel University, Germany
Position: Professor, Department of Civil
Engineering, National Taipei University of
Technology
Research interest: Watershed Modelling and
Management, Ecological Engineering
Number of papers published: 19
Number of conferences/seminars attended: 50
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The SIJ Transactions on Advances in Space Research & Earth Exploration (ASREE), Vol. 1, No. 2, November-December 2013
ISSN: 2347 – 6087 © 2013 | Published by The Standard International Journals (The SIJ) 54
Tsung-Ming YANG
Education: Master, of Construction
Engineering, National Taiwan University of
Science and Technology, Taiwan
Position: Chief Secretary, Water Resources
Department, New Taipei City Government,
New Taipei City, Taiwan
Research interest: Water resource
Management、Waste water Treatment、Flow Measure
Number of papers published: 2
Number of conferences/seminars attended: 11
Kuan-Han CHOU Education: Master, Civil Engineering,
National Taipei University of Technology,
Taiwan
Position: Engineer, 5th River Management
Office, Water Resource Agency, Taiwan
Research interest: Geosynthetics application,
Erosion behaviour of revetments
Number of papers published: 1
Number of conferences/seminars attended: 2