Physically-based Watershed Health, Resilience, and ... · Physically-based Watershed Health,...

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


Green area 0.93

Active river area 0.82


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

component

value

=

Sub-index




Watershed

health

index


Sub-index x)




Stream geomorphology 0.93





Stream length


Stream geomorphology


Stream length of reference condition

Total stream length in watershed

Geomorphology

Dam & Weir

Multifunction Weir

Multipurpose &

Hydroelectric Dam

Standard Watershed

Mid-watershed

12


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

component

value

Simulated value of watershed

Avg. value for all watersheds=

Sub-index




Watershed

health

index


Sub-index x)




Total 0.97

Surface Processes 0.61

Soil Water Dynamics 0.99

Groundwater Dynamics 0.95



Total 0.01

Surface Processes 0.16

Soil Water Dynamics 0.78

Groundwater Dynamics 0.17


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


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

component

value

Simulated value of watershed

Reference value in watershed=

Sub-index




Watershed

health

index


Sub-index x)




Sediment 0.05

T-N 0.43

T-P 0.41



Sediment 0.52

T-N 0.91

T-P 0.46


T-N T-PSediment

Dam & Weir

Multifunction Weir

Multipurpose &

Hydroelectric Dam

Standard Watershed

Mid-watershed

16


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




Watershed

health

index


Sub-index x)




Habitat connectivity Wetland


Habitat connectivity 0.46

Wetland 0.34



Habitat connectivity 0.00

Wetland 0.99


Aquatic Habitat

Dam & Weir

Multifunction Weir

Multipurpose &

Hydroelectric Dam

Standard Watershed

Mid-watershed

18


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

component

value

Observed value for watershed

Reference value in watershed=

Sub-index




Watershed

health

index


Sub-index x)




TDI 0.69

BMI 0.98

FAI 0.72



TDI 0.70

BMI 0.98

FAI 0.92


BMI FAITDI

Biological Condition

Dam & Weir

Multifunction Weir

Multipurpose &

Hydroelectric Dam

Standard Watershed

Mid-watershed

20


Watershed Health

Low

(0)

High

(1)

Watershed health

Integrated Watershed Health Index Standard watershed 101206

Landscape 0.89


Hydrology 0.06

Water quality 0.77

Aquatic habitat condition 0.90

Biological condition 0.91

Integrated watershed health 1.00


Landscape 0.66


Hydrology 0.96

Water quality 0.10





Landscape 0.17


Hydrology 0.85

Water quality 0.03




Landscape Stream

geomorphology

Hydrology Water Quality

Aquatic habitat

conditionBiological

condition

Dam & Weir

Multifunction Weir


Standard Watershed

Mid-watershed

No data

21

Vulnerability index (Impervious area change)


Normalized

component

value

Impervious area in 2050 - Impervious area in 2008

Impervious area in 2008=

Sub-index




Watershed

vulnerability

index


Sub-index x)



Impervious Area Change

Impervious area

(2008)

Impervious area change

(2008 vs. 2050)

Impervious area

(2050 by CLUEs)


Impervious area change 0.68

Watershed vulnerability 0.68




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

component

value

=

Sub-index





Sub-index x)



Climate Change

Precipitation change

Min. temperature change

Max. temperature change

Watershed

vulnerability

index


Precipitation change 0.98

Max. temperature change 0.73

Min. temperature change 0.78



Precipitation change 0.39

Max. temperature change 0.62

Min. temperature change 0.64


Low

(0)

High

(1)


Dam & Weir

Multifunction Weir

Multipurpose &

Hydroelectric Dam

Standard Watershed

Mid-watershed


23

Baseline (1976-2005) vs. HadGEM2-AO RCP 8.5 (2050s)

Vulnerability index (Water use change)


Normalized

component

value

=

Sub-index





Sub-index x)



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


Domestic water use change 0.15

Industrial water use change 0.39

Agricultural water use change 0.57



Domestic water use change 0.17

Industrial water use change 0.26

Agricultural water use change 0.35


Low

(0)

High

(1)


Dam & Weir

Multifunction Weir

Multipurpose &

Hydroelectric Dam

Standard Watershed

Mid-watershed


24

Vulnerability index (Recent land cover change)


Normalized

component

value

Anthropogenic land cover in 2014

- Anthropogenic land cover in 2008

Anthropogenic land cover in 2008=

Sub-index




Watershed

vulnerability

index


Sub-index x)



Anthropogenic land cover

(2008)

Recent land cover change

(2008 vs. 2014)

Anthropogenic land cover

(2014)


Recent land cover change 0.79





Low

(0)

High

(1)


Recent Land Cover Change

Dam & Weir

Multifunction Weir

Multipurpose &

Hydroelectric Dam

Standard Watershed

Mid-watershed

25


Watershed VulnerabilityWatershed Vulnerability Index



Climate change 0.40

Water use change 0.22


Integrated vulnerability 0.20



Climate change 0.95






Climate change 0.15




Impervious

land cover

change

Climate

change

Water use

changeRecent

land cover

change

Low

(0)

High

(1)


Dam & Weir

Multifunction Weir


Standard Watershed

Mid-watershed

No data

26


Social Context Index

Normalized

component

value

=

Sub-index





Sub-index x)



Financial independence rate

Water management public officer

GRDP (gross regional domestic

product )

Observed value of watershed

Maximum value for all watersheds

Watershed

vulnerability

index


Financial independence rate 0.22

GRDP 0.27

WM public officer 0.33

Social context 0.23


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


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


Standard Watershed

Mid-watershed

Protect

Protection Priority

Restore


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


Resilience (≥medium)

Standard Watershed

Mid-watershed

High

Medium

Low

Standard Watershed

Mid-watershed

Resilience

+ Restoration Priorities

(a) (b) (c)

Protect

Protection Priority

Restore


Standard Watershed

Mid-watershed

Resilience + Priority

Dam & Weir

Multifunction Weir


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/

mailto:[email protected],kr

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