2016 International SWAT Conference
Physically-based Watershed Health, Resilience,
and Priority Assessment of the Han River Basin
in South Korea
July 27, 2016
So Ra AHN
Ji Wan LEE, Chung Gil JUNG, Da Rae KIM, So Yeon KIM and Seong Joon KIM
Earth Information Engineering Laboratory
Department of Civil and Environmental System Engineering
Konkuk University
SESSION A2:
ENVIRONMENTAL APPLICATIONS
Meeting Room No.2
2016 International SWAT Conference
July 27-29, 2016, Beijing, China
• Introduction (Why this study?)
• Materials and Method
Study Area
Data Collection
Data Reconstruction for Watershed Health (using SWAT model)
Data Reconstruction for Watershed Vulnerability
Data Reconstruction for Social Context
• Results and Discussion
Assessment of Watershed Health, Vulnerability, and Social Context
Analysis of Watershed Resilience and Priorities for Protection and
Restoration
• Conclusions
Objectives2
Introduction (why this study?)
A good watershed management can be defined as the integrated and repetitive
decision process to maintain the sustainability of resources through balanced
use and conservation of water quantity, land, vegetation, and other natural
resources within the watershed.
With the watershed health assessment system, we can have more success in
restoring impaired waters and get the many socio-economic benefits from the
healthy watershed.
Through the integrated assessment results, the local government can get the
helpful information of curing weak component of watershed health among water
supply, water quality, and natural ecosystem or their interactions.
The main objective of this study is to suggest an application strategy for
protection and restoration priorities at the watershed scale based on watershed
health, vulnerability, and resilience assessments (introduced by U.S. EPA) of the
Han River basin (34,148 km²) in South Korea.
3
North Korea
South Korea
Multi-purpose
DamMulti-function
weir
Han River
Basin
5 Major river basins in our country
(Han, Geum, Yeongsan, Seomjin,
and Nakdong)
Now the Han River basin has well-
established water resources
management system with 4
multipurpose dams and 3 big weirs
especially for Seoul metropolitan
and the satellite cities.
Due to the increase of population
and agricultural activities since 1970,
the watershed health has been
deteriorated in terms of water
supply capacity, required water
quality, and necessary ecological
condition.
The Han River basin is a good
candidate to apply the healthy
watershed assessment.
5 Major River Basins of South Korea
Nakdong River
Geum River
Seomjin River
Yeongsan
River
4
Research Procedure
(Integrated Watershed Health & Vulnerability Assessment)
DEM (90m×90m)
Land cover (2008)
Stream (national,
local, small)
Standard
watershed unit
map
GIS Data
Hydrology (1984-2014)○ Total (PREC,TQ)
○ Surface processes (SQ)
○ Soil water dynamics
(INFILT, SW, LQ)
○ Groundwater dynamics
(PERCOL, RECHARGE, GWQ)
Water quality (1984-2014)○ Sediment, T-N, T-P
SWAT Modeling Output
Reservoirs location
and number
Wetland area
TDI, BMI, FAI
Monitoring Data
RCP scenario (8.5 2050s)
○ Annual temperature
○ Annual Precipitation
Water use (2020)
○ Groundwater use
CLUEs land cover (2050)
○ Impervious area
Future Data
Assessment of Integrated Watershed Health Assessment of Watershed Vulnerability
Monitoring Data & Modeling Output
Weather (1984-2014)
○ Annual temperature
○ Annual precipitation
Water use (2006)
○ Groundwater use
Land cover (2008, 2014)
○ Impervious area
Present Data
Set Strategic Management PrioritiesWatershed Resilience Analysis
Priorities matrix for setting protection and restoration priorities using watershed health and vulnerability scores
Strategy management for protection and restoration priorities○ National, local government
Resilience screening○ Integrated capacity assessment○ Stressor exposure○ Social context
Present & Future Data
Green area
Riparian area
Landscape
Stream geomorphology
Hydrology (with SWAT)
Water quality (with SWAT)
Aquatic habitat condition
Biological condition
Stream
geomorphology
Total
Surface processes
Soil water dynamics
Groundwater dynamics
Sediment
T-N
T-P
Aquatic habitat
connectivity
Wetland
TDI
BMI
FAI
Projected Impervious land
cover compared with
current impervious land
cover
Impervious area change
Recent land cover change
Climate change
Water use change
Recent anthropogenic land
cover change
Temperature and
precipitation change
Projected water use
compared with current
water use
SOCIAL PROCESS
(Management and Planning)
Monitoring Data & Modeling Output
SCIENTIFIC PROCESS
5
Namhan River
Bukhan River
Han River
SYD
HSD
CJD
KCWYJW
IPW
PDD
Study Area
China
Japan
South Korea
Han River
Nakdong River
Seomjin River
Youngsan
River
Geum River
(a)
(b)
Watershed
outlet
SWATSub-watersheds: 237
Han River BasinStandard watersheds: 237
Land cover classificationUrban
Rice paddy
Upland crop
Deciduous forest
Mixed forest
Coniferous forest
Grassland
Bare field
Water
Dam & Weir
Multifunction Weir
Multipurpose & Hydroelectric Dam
Observation Station
Weather Station
ET & SM Station
Groundwater Level Station
Water Quality Station
Watershed & Stream
Stream
Standard Watershed
Han River Basin
Han River basin (34,148 km2)
Average annual precipitation 1,395 mm/year
Mean annual temperature 11.5℃
6
(c)
North Korea
South Korea
North Korea
Data Collection
Watershed Health Components (introduced by U.S. EPA)
7
Data Collection
Watershed Vulnerability Components (introduced by U.S. EPA)
Social Context Components
8
area changes
Green area
(natural land cover in watershed)
LandscapeActive river area
(natural land cover in active river area)
Natural land cover
Water
Standard Watershed
Natural land cover (%)
0 - 20
21 - 40
41 - 60
61 - 80
91 - 100
Water
Standard Watershed
(a) (b)
9
* Natural land cover: forest, wetland, river, and natural grassland
Watershed health index (Landscape)
Low
(0)
High
(1)
Watershed health
Normalized sub-index
Watershed health index
Normalized
component
value
Area of natural land cover in watershed
Total area in watershed=
Sub-index
(Normalized value 1 + Normalized
value 2 + ... + Normalized value x)
Total number of normalized values=
Watershed
health
index
(Sub-index 1 + Sub-index 2 + … +
Sub-index x)
Total number of sub-indices=
Ref.) EPA 2012, Identifying and Protecting Healthy Watersheds
Standard watershed 100201
Green area 0.78
Active river area 0.57
Watershed health 0.66
Standard watershed 101206
Green area 0.93
Active river area 0.82
Watershed health 0.89
Green area
(natural land cover in watershed)
Active river area
(natural land cover in Active river area)
Landscape
Dam & Weir
Multifunction Weir
Multipurpose &
Hydroelectric Dam
Standard Watershed
Mid-watershed
10
Stream order (1~9) Stream geomorphic condition
(reference condition)
Poor
Fair
Good
Reference
Standard Watershed
Stream Order 9
Stream Order 8
Stream Order 7
Stream Order 6
Stream Order 5
Stream Order 4
Stream Order 3
Stream Order 2
Stream Order 1
Standard Watershed
(a) (b)
Geomorphology11
Watershed health index (geomorphology)
Low
(0)
High
(1)
Watershed health
Normalized sub-index
Normalized
component
value
=
Sub-index
(Normalized value 1 + Normalized
value 2 + ... + Normalized value x)
Total number of normalized values=
Watershed
health
index
(Sub-index 1 + Sub-index 2 + … +
Sub-index x)
Total number of sub-indices=
Ref.) EPA 2012, Identifying and Protecting Healthy Watersheds
Standard watershed 100201
Stream geomorphology 0.93
Watershed health 0.93
Standard watershed 101206
Stream geomorphology 0.94
Watershed health 0.94
Stream length
(reference condition)
Stream geomorphology
(reference condition)
Stream length of reference condition
Total stream length in watershed
Geomorphology
Dam & Weir
Multifunction Weir
Multipurpose &
Hydroelectric Dam
Standard Watershed
Mid-watershed
12
Watershed health index
Comparison of the water balance components 30 years (1985-2014) SWAT modeling results
Hydrology
Total Q (mm)Precipitation (mm) Surface runoff (mm)
Percolation (mm)
SW storage(mm) Lateral Q (mm)Infiltration (mm)
GW recharge (mm) Return Q (mm)
Total Surface Processes
Soil Water Dynamics
Groundwater Dynamics
• Weather
• Hydrology
• Sedimentation
• Plant growth
• Nutrient Cycling
• Pesticide Dynamics
• Management
• Bacteria
SWAT model(Soil and Water
Assessment Tool)
Ref.) Arnold et al., 1998, Large area
hydrologic modeling and assessment:
part I. Model development
13
Watershed health index (hydrology) 30 years (1985-2014)
Low
(0)
High
(1)
Watershed health
Normalized sub-index
Normalized
component
value
Simulated value of watershed
Avg. value for all watersheds=
Sub-index
(Normalized value 1 + Normalized
value 2 + ... + Normalized value x)
Total number of normalized values=
Watershed
health
index
(Sub-index 1 + Sub-index 2 + … +
Sub-index x)
Total number of sub-indices=
Ref.) EPA 2012, Identifying and Protecting Healthy Watersheds
Standard watershed 100201
Total 0.97
Surface Processes 0.61
Soil Water Dynamics 0.99
Groundwater Dynamics 0.95
Watershed health 0.96
Standard watershed 101206
Total 0.01
Surface Processes 0.16
Soil Water Dynamics 0.78
Groundwater Dynamics 0.17
Watershed health 0.06
Surface Processes
(SQ)
Soil Water Dynamics
(INFILT,SW,LQ)
Groundwater Dynamics
(PERCOL,RECHARGE,GWQ)
Total
(PREC,TQ)
Hydrology
Dam & Weir
Multifunction Weir
Multipurpose &
Hydroelectric Dam
Standard Watershed
Mid-watershed
14
Watershed health index
Water Quality
Sediment (ton) T-N (kg) T-P (kg)
Sediment (mg/L) T-N (mg/L) T-P (mg/L)
Comparison of the water quality components 30 years (1985-2014) SWAT modeling results
• Weather
• Hydrology
• Sedimentation
• Plant growth
• Nutrient Cycling
• Pesticide Dynamics
• Management
• Bacteria
SWAT model(Soil and Water
Assessment Tool)
Ref.) Arnold et al., 1998, Large area
hydrologic modeling and assessment:
part I. Model development
15
Watershed health index (water quality) 30 years (1985-2014)
Water Quality
Low
(0)
High
(1)
Watershed health
Normalized sub-index
Normalized
component
value
Simulated value of watershed
Reference value in watershed=
Sub-index
(Normalized value 1 + Normalized
value 2 + ... + Normalized value x)
Total number of normalized values=
Watershed
health
index
(Sub-index 1 + Sub-index 2 + … +
Sub-index x)
Total number of sub-indices=
Ref.) EPA 2012, Identifying and Protecting Healthy Watersheds
Standard watershed 100201
Sediment 0.05
T-N 0.43
T-P 0.41
Watershed health 0.10
Standard watershed 101206
Sediment 0.52
T-N 0.91
T-P 0.46
Watershed health 0.77
T-N T-PSediment
Dam & Weir
Multifunction Weir
Multipurpose &
Hydroelectric Dam
Standard Watershed
Mid-watershed
16
Watershed health index
Aquatic Habitat
Reservoirs
Stream
Standard Watershed
Aquatic habitat connectivity Wetland
Wetlands
Stream
Standard Watershed
(a) (b)
17
Watershed health index (aquatic habitat)
Low
(0)
High
(1)
Watershed health
Normalized
component
value
Number of reservoirs in watershed
Total stream length in watershed=
Sub-index
(Normalized value 1 + Normalized
value 2 + ... + Normalized value x)
Total number of normalized values=
Watershed
health
index
(Sub-index 1 + Sub-index 2 + … +
Sub-index x)
Total number of sub-indices=
Ref.) EPA 2012, Identifying and Protecting Healthy Watersheds
Normalized sub-index
Habitat connectivity Wetland
Standard watershed 100201
Habitat connectivity 0.46
Wetland 0.34
Watershed health 0.28
Standard watershed 101206
Habitat connectivity 0.00
Wetland 0.99
Watershed health 0.90
Aquatic Habitat
Dam & Weir
Multifunction Weir
Multipurpose &
Hydroelectric Dam
Standard Watershed
Mid-watershed
18
Watershed health index
TDI
(Trophic Diatom Index)
Biological Condition
BMI
(Benthic Macroinvertebrate Index)
FAI
(Fish Assessment Index)
(a) (b)
A (Poor) 0≤~<30B (Fair) 30≤~<45C (Good) 45≤~<60D (Best) 60≤~≤100
A (Poor) 0≤~<45B (Fair) 45≤~<60C (Good) 60≤~<80D (Best) 80≤~≤100
A (Poor) 0≤~<25B (Fair) 25≤~<56.2C (Good) 56.2≤~<87.5D (Best) 87.5≤~≤100
(c)
TDI BMI FAI
19
Watershed health index (biological condition) 6 years (2008-2013) observed data
Low
(0)
High
(1)
Watershed health
Normalized sub-index
Normalized
component
value
Observed value for watershed
Reference value in watershed=
Sub-index
(Normalized value 1 + Normalized
value 2 + ... + Normalized value x)
Total number of normalized values=
Watershed
health
index
(Sub-index 1 + Sub-index 2 + … +
Sub-index x)
Total number of sub-indices=
Ref.) EPA 2012, Identifying and Protecting Healthy Watersheds
Standard watershed 100201
TDI 0.69
BMI 0.98
FAI 0.72
Watershed health 0.83
Standard watershed 101206
TDI 0.70
BMI 0.98
FAI 0.92
Watershed health 0.91
BMI FAITDI
Biological Condition
Dam & Weir
Multifunction Weir
Multipurpose &
Hydroelectric Dam
Standard Watershed
Mid-watershed
20
Watershed health index
Watershed Health
Low
(0)
High
(1)
Watershed health
Integrated Watershed Health Index Standard watershed 101206
Landscape 0.89
Stream geomorphology 0.94
Hydrology 0.06
Water quality 0.77
Aquatic habitat condition 0.90
Biological condition 0.91
Integrated watershed health 1.00
Standard watershed 100201
Landscape 0.66
Stream geomorphology 0.93
Hydrology 0.96
Water quality 0.10
Aquatic habitat condition 0.28
Biological condition 0.83
Integrated watershed health 0.91
Standard watershed 101801
Landscape 0.17
Stream geomorphology 0.63
Hydrology 0.85
Water quality 0.03
Aquatic habitat condition 0.68
Biological condition 0.26
Integrated watershed health 0.25
Landscape Stream
geomorphology
Hydrology Water Quality
Aquatic habitat
conditionBiological
condition
Dam & Weir
Multifunction Weir
Multipurpose & Hydroelectric Dam
Standard Watershed
Mid-watershed
No data
21
Vulnerability index (Impervious area change)
Normalized sub-index
Normalized
component
value
Impervious area in 2050 - Impervious area in 2008
Impervious area in 2008=
Sub-index
(Normalized value 1 + Normalized
value 2 + ... + Normalized value x)
Total number of normalized values=
Watershed
vulnerability
index
(Sub-index 1 + Sub-index 2 + … +
Sub-index x)
Total number of sub-indices=
Ref.) EPA 2012, Identifying and Protecting Healthy Watersheds
Impervious Area Change
Impervious area
(2008)
Impervious area change
(2008 vs. 2050)
Impervious area
(2050 by CLUEs)
Standard watershed 100201
Impervious area change 0.68
Watershed vulnerability 0.68
Standard watershed 101206
Impervious area change 0.00
Watershed vulnerability 0.00
Low
(0)
High
(1)
Watershed vulnerability
Dam & Weir
Multifunction Weir
Multipurpose &
Hydroelectric Dam
Standard Watershed
Mid-watershed
22
Watershed vulnerability index
Avg. annual precip. in 2050s under the
RCP scenario - Avg. annual precip. for
baseline (1976-2005)
Vulnerability index (Climate change)
Normalized sub-index
Normalized
component
value
=
Sub-index
(Normalized value 1 + Normalized
value 2 + ... + Normalized value x)
Total number of normalized values=
(Sub-index 1 + Sub-index 2 + … +
Sub-index x)
Total number of sub-indices=
Ref.) EPA 2012, Identifying and Protecting Healthy Watersheds
Climate Change
Precipitation change
Min. temperature change
Max. temperature change
Watershed
vulnerability
index
Standard watershed 100201
Precipitation change 0.98
Max. temperature change 0.73
Min. temperature change 0.78
Watershed vulnerability 0.95
Standard watershed 101206
Precipitation change 0.39
Max. temperature change 0.62
Min. temperature change 0.64
Watershed vulnerability 0.40
Low
(0)
High
(1)
Watershed vulnerability
Dam & Weir
Multifunction Weir
Multipurpose &
Hydroelectric Dam
Standard Watershed
Mid-watershed
Watershed vulnerability index
23
Baseline (1976-2005) vs. HadGEM2-AO RCP 8.5 (2050s)
Vulnerability index (Water use change)
Normalized sub-index
Normalized
component
value
=
Sub-index
(Normalized value 1 + Normalized
value 2 + ... + Normalized value x)
Total number of normalized values=
(Sub-index 1 + Sub-index 2 + … +
Sub-index x)
Total number of sub-indices=
Ref.) EPA 2012, Identifying and Protecting Healthy Watersheds
Water Use Change
Domestic water use change
Agricultural water
use change
Industrial water use change
Water use in 2020 - Water use in 2006
Water use in 2006
Watershed
vulnerability
index
Standard watershed 100201
Domestic water use change 0.15
Industrial water use change 0.39
Agricultural water use change 0.57
Watershed vulnerability 0.28
Standard watershed 101206
Domestic water use change 0.17
Industrial water use change 0.26
Agricultural water use change 0.35
Watershed vulnerability 0.22
Low
(0)
High
(1)
Watershed vulnerability
Dam & Weir
Multifunction Weir
Multipurpose &
Hydroelectric Dam
Standard Watershed
Mid-watershed
Watershed vulnerability index
24
Vulnerability index (Recent land cover change)
Normalized sub-index
Normalized
component
value
Anthropogenic land cover in 2014
- Anthropogenic land cover in 2008
Anthropogenic land cover in 2008=
Sub-index
(Normalized value 1 + Normalized
value 2 + ... + Normalized value x)
Total number of normalized values=
Watershed
vulnerability
index
(Sub-index 1 + Sub-index 2 + … +
Sub-index x)
Total number of sub-indices=
Ref.) EPA 2012, Identifying and Protecting Healthy Watersheds
Anthropogenic land cover
(2008)
Recent land cover change
(2008 vs. 2014)
Anthropogenic land cover
(2014)
Standard watershed 100201
Recent land cover change 0.79
Watershed vulnerability 0.79
Standard watershed 101206
Recent land cover change 0.36
Watershed vulnerability 0.36
Low
(0)
High
(1)
Watershed vulnerability
Recent Land Cover Change
Dam & Weir
Multifunction Weir
Multipurpose &
Hydroelectric Dam
Standard Watershed
Mid-watershed
25
Watershed vulnerability index
Watershed VulnerabilityWatershed Vulnerability Index
Standard watershed 101206
Impervious area change 0.00
Climate change 0.40
Water use change 0.22
Recent land cover change 0.36
Integrated vulnerability 0.20
Standard watershed 100201
Impervious area change 0.68
Climate change 0.95
Water use change 0.28
Recent land cover change 0.79
Integrated vulnerability 0.86
Standard watershed 101801
Impervious area change 0.00
Climate change 0.15
Water use change 0.70
Recent land cover change 0.15
Integrated vulnerability 0.20
Impervious
land cover
change
Climate
change
Water use
changeRecent
land cover
change
Low
(0)
High
(1)
Watershed vulnerability
Dam & Weir
Multifunction Weir
Multipurpose & Hydroelectric Dam
Standard Watershed
Mid-watershed
No data
26
Normalized sub-index
Social Context Index
Normalized
component
value
=
Sub-index
(Normalized value 1 + Normalized
value 2 + ... + Normalized value x)
Total number of normalized values=
(Sub-index 1 + Sub-index 2 + … +
Sub-index x)
Total number of sub-indices=
Ref.) EPA 2012, Identifying and Protecting Healthy Watersheds
Financial independence rate
Water management public officer
GRDP (gross regional domestic
product )
Observed value of watershed
Maximum value for all watersheds
Watershed
vulnerability
index
Standard watershed 100201
Financial independence rate 0.22
GRDP 0.27
WM public officer 0.33
Social context 0.23
Standard watershed 101206
Financial independence rate 0.18
GRDP 0.47
WM public officer 0.29
Social context 0.18
Low
(0)
High
(1)
Social Context
Social context
Dam & Weir
Multifunction Weir
Multipurpose &
Hydroelectric Dam
Standard Watershed
Mid-watershed
27
Resilience + Priority
Watershed resilience analysis
(Recovery potential)
Stressor Indicator Summary Scores
Inte
gra
ted
Cap
acit
y
Ind
ica
tor
Su
mm
ary
Sc
ore
s
Pass
Fail
Zone A Zone B
Zone D Zone C
Priorities matrix for setting protection and
restoration priorities
* Circle size increases with social context summary score value
Ref.) (Norton et al., 2009, A Method for Comparative Analysis of
Recovery Potential in Impaired Waters Restoration Planning.
Environmental Management 44:356-368.
Ref.) U.S. EPA. 2012, Identifying and Protecting Healthy
Watersheds: Concepts, Assessments, and Management
Approaches. EPA 841-B-11-002.
(a) (b)
ProtectProtection
Priority
Restoration
PriorityRestore
High
High
Low
Low
Wa
ters
he
d H
ea
lth
Vulnerability
Site-specific
Determination
Zone A Zone B
Zone D Zone C
28
Resilience (Recovery Potential)Stressor indicator
summary scores
(Vulnerability)
Integrated capacity indicator
summary scores
(Health)
Social context
summary scores Watershed Resilience Analysis
High
Medium
Low
Standard Watershed
Mid-watershed
Dam & Weir
Multifunction Weir
Multipurpose & Hydroelectric Dam
Standard Watershed
Mid-watershed
Han river basin
High
Medium
Low
Integrated(hydrological + water quality + ecological)
Cluster Analysis
29
Protection and Restoration Priority
Integrated Watershed
Vulnerability Index
Integrated Watershed
Health Index
Protect
Protection Priority
Restore
Restoration Priority
Standard Watershed
Mid-watershed
Dam & Weir
Multifunction Weir
Multipurpose & Hydroelectric Dam
Standard Watershed
Mid-watershed
Protect
Protection Priority
Restore
Restoration Priority
A
B
C
D
Zone A Zone D
Zone B Zone C
A
D C
B
Protection and Restoration PrioritiesStandard Watershed
30
Protection and Restoration
Priorities
Watershed Resilience
Analysis
Restore
Restoration Priority
Resilience (≥medium)
Standard Watershed
Mid-watershed
High
Medium
Low
Standard Watershed
Mid-watershed
Resilience
+ Restoration Priorities
(a) (b) (c)
Protect
Protection Priority
Restore
Restoration Priority
Standard Watershed
Mid-watershed
Resilience + Priority
Dam & Weir
Multifunction Weir
Multipurpose & Hydroelectric Dam
Standard Watershed
Mid-watershed
31
Summary and Conclusions
The analysis of resilience and protection and restoration priorities was conducted through the
quantification of watershed health, vulnerability, and social context for watershed management
strategy in Han River basin.
The resilience screening was conducted to assess the recovery potential of watershed
using the results of integrated capacity, stressor exposure, and social context.
The results of watershed health and vulnerability assessments can be used to set
strategic management priorities at the watershed scale.
Most of the regions in the SYD and CJD watersheds in the upstream area of the Han River
basin required protection or protection priority, and most regions in the downstream area of
the PDD watersheds required restoration or restoration priority.
The sub-index results of the watershed health assessment for each component can be used to
guide the master planning process for watershed management at the watershed scale based
on specific management objectives and can be combined with any of the other sub-indices in
the Han River basin for use in determining priority conservation areas.
We intend to further study and adapt climate change-based algorithms for the protection and
restoration priorities of watersheds nationwide. We feel that further work on the management
approaches to integrated watershed assessment will support decision making by national and
local governments.
32
Thank you
Earth Information Engineering Lab.
So Ra AHNDept. of Civil and Environmental System Engineering
Konkuk University, Seoul, South Korea
Phone: +82-2-444-0186
Email: [email protected],kr
Web: http://konkuk.ac.kr/~kimsj/
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