Physically-based Watershed Health, Resilience, and Priority Assessment of the Han River Basin in South Korea

Transcription

1 2016 International SWAT Conference July 27-29, 2016, Beijing, China SESSION A2: ENVIRONMENTAL APPLICATIONS Meeting Room No 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

2 Objectives 2 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

3 Introduction (why this study?) 3 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.

4 5 Major River Basins of South Korea 4 Multi-function weir Geum River North Korea Han River Basin South Korea Multi-purpose Dam Nakdong River 5 Major river basins in our country (Han, Geum, Yeongsan, Seomjin, and Nakdong) Now the Han River basin has wellestablished 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. Yeongsan River Seomjin River The Han River basin is a good candidate to apply the healthy watershed assessment.

5 Research Procedure 5 Monitoring Data & Modeling Output GIS Data SWAT Modeling Output Hydrology ( ) DEM (90m 90m) Total (PREC,TQ) Land cover (2008) Surface processes (SQ) Stream (national, Soil water dynamics local, small) (INFILT, SW, LQ) Standard Groundwater dynamics watershed unit (PERCOL, RECHARGE, GWQ) map Water quality ( ) Sediment, T-N, T-P Monitoring Data Reservoirs location and number Wetland area TDI, BMI, FAI Present & Future Data Present Data Weather ( ) Annual temperature Annual precipitation Water use (2006) Groundwater use Land cover (2008, 2014) Impervious area Future Data RCP scenario ( s) Annual temperature Annual Precipitation Water use (2020) Groundwater use CLUEs land cover (2050) Impervious area SCIENTIFIC PROCESS (Integrated Watershed Health & Vulnerability Assessment) Assessment of Integrated Watershed Health Assessment of Watershed Vulnerability Landscape Green area Riparian area Stream geomorphology Stream geomorphology Hydrology (with SWAT) Total Surface processes Soil water dynamics Groundwater dynamics Water quality (with SWAT) Sediment T-N T-P SOCIAL PROCESS (Management and Planning) Watershed Resilience Analysis Resilience screening Integrated capacity assessment Stressor exposure Social context Aquatic habitat condition Aquatic habitat connectivity Wetland Biological condition TDI BMI FAI Impervious area change Projected Impervious land cover compared with current impervious land cover Recent land cover change Recent anthropogenic land cover change Set Strategic Management Priorities Climate change Temperature and precipitation change Water use change Projected water use compared with current water use Priorities matrix for setting protection and restoration priorities using watershed health and vulnerability scores Strategy management for protection and restoration priorities National, local government

6 Study Area 6 China North Korea South Korea Han River Geum River Nakdong River (a) Watershed outlet Bukhan River SWAT Sub-watersheds: 237 Han River Basin Standard watersheds: 237 North Korea (b) Youngsan River Seomjin River Japan Multipurpose & Hydroelectric Dam Observation Station Weather Station ET & SM Station Groundwater Level Station Water Quality Station Watershed & Stream Stream Han River Basin Land cover classification Urban Rice paddy Upland crop Deciduous forest Mixed forest Coniferous forest Grassland Bare field Water Han River PDD SYD IPW YJW KCW Han River basin (34,148 km 2 ) HSD CJD Namhan River Average annual precipitation 1,395 mm/year Mean annual temperature 11.5 South Korea (c)

7 Data Collection 7 Watershed Health Components (introduced by U.S. EPA)

8 Data Collection 8 Watershed Vulnerability Components (introduced by U.S. EPA) area changes Social Context Components

9 Landscape 9 Green area (natural land cover in watershed) Active river area (natural land cover in active river area) (a) (b) Natural land cover Water Natural land cover (%) Water * Natural land cover: forest, wetland, river, and natural grassland

10 Landscape 10 Watershed health index (Landscape) Normalized sub-index Green area (natural land cover in watershed) Active river area (natural land cover in Active river area) Watershed health index Multipurpose & Hydroelectric Dam Normalized component value Sub-index Area of natural land cover in watershed Total area in watershed (Normalized value 1 + Normalized value Normalized value x) Total number of normalized values Standard watershed Green area 0.93 Active river area 0.82 Watershed health 0.89 Standard watershed Watershed health index (Sub-index 1 + Sub-index Sub-index x) Total number of sub-indices Ref.) EPA 2012, Identifying and Protecting Healthy Watersheds Green area 0.78 Active river area 0.57 Watershed health 0.66 (0) Watershed health (1)

11 Geomorphology 11 Stream order (1~9) Stream geomorphic condition (reference condition) (a) (b) 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 Poor Fair Good Reference

12 Geomorphology 12 Watershed health index (geomorphology) Normalized sub-index Stream length (reference condition) Stream geomorphology (reference condition) Watershed health index Multipurpose & Hydroelectric Dam Normalized component value Stream length of reference condition Total stream length in watershed Standard watershed Sub-index (Normalized value 1 + Normalized value Normalized value x) Total number of normalized values Stream geomorphology 0.94 Watershed health 0.94 Watershed health index (Sub-index 1 + Sub-index Sub-index x) Total number of sub-indices Ref.) EPA 2012, Identifying and Protecting Healthy Watersheds Standard watershed Stream geomorphology 0.93 Watershed health 0.93 (0) Watershed health (1)

13 Hydrology 13 Comparison of the water balance components 30 years ( ) SWAT modeling results Total Precipitation (mm) Total Q (mm) Surface Processes Surface runoff (mm) SWAT model (Soil and Water Assessment Tool) Soil Water Dynamics Infiltration (mm) SW storage(mm) Lateral Q (mm) Weather Hydrology Sedimentation Plant growth Nutrient Cycling Pesticide Dynamics Management Bacteria Groundwater Dynamics Percolation (mm) GW recharge (mm) Return Q (mm) Ref.) Arnold et al., 1998, Large area hydrologic modeling and assessment: part I. Model development

14 Hydrology 14 Watershed health index (hydrology) 30 years ( ) Normalized sub-index Total (PREC,TQ) Surface Processes (SQ) Soil Water Dynamics Groundwater Dynamics (INFILT,SW,LQ) (PERCOL,RECHARGE,GWQ) Watershed health index Multipurpose & Hydroelectric Dam Normalized component value Sub-index Watershed health index Simulated value of watershed Avg. value for all watersheds (Normalized value 1 + Normalized value Normalized value x) Total number of normalized values (Sub-index 1 + Sub-index Sub-index x) Total number of sub-indices Ref.) EPA 2012, Identifying and Protecting Healthy Watersheds Standard watershed Total 0.01 Surface Processes 0.16 Soil Water Dynamics 0.78 Groundwater Dynamics 0.17 Watershed health 0.06 Standard watershed Total 0.97 Surface Processes 0.61 Soil Water Dynamics 0.99 Groundwater Dynamics 0.95 Watershed health 0.96 (0) Watershed health (1)

15 Water Quality 15 Comparison of the water quality components 30 years ( ) SWAT modeling results Sediment (ton) T-N (kg) T-P (kg) SWAT model (Soil and Water Assessment Tool) Sediment (mg/l) T-N (mg/l) T-P (mg/l) Weather Hydrology Sedimentation Plant growth Nutrient Cycling Pesticide Dynamics Management Bacteria Ref.) Arnold et al., 1998, Large area hydrologic modeling and assessment: part I. Model development

16 Water Quality 16 Watershed health index (water quality) 30 years ( ) Normalized sub-index Sediment T-N T-P Watershed health index Multipurpose & Hydroelectric Dam Normalized component value Sub-index Simulated value of watershed Reference value in watershed (Normalized value 1 + Normalized value Normalized value x) Total number of normalized values Standard watershed Sediment 0.52 T-N 0.91 T-P 0.46 Watershed health 0.77 Standard watershed Watershed health index (Sub-index 1 + Sub-index Sub-index x) Total number of sub-indices Ref.) EPA 2012, Identifying and Protecting Healthy Watersheds Sediment 0.05 T-N 0.43 T-P 0.41 Watershed health 0.10 (0) Watershed health (1)

17 Aquatic Habitat 17 Aquatic habitat connectivity Wetland (a) (b) Reservoirs Stream Wetlands Stream

18 Aquatic Habitat 18 Watershed health index (aquatic habitat) Normalized sub-index Habitat connectivity Wetland Watershed health index Multipurpose & Hydroelectric Dam Normalized component value Sub-index Number of reservoirs in watershed Total stream length in watershed (Normalized value 1 + Normalized value Normalized value x) Total number of normalized values Standard watershed Habitat connectivity 0.00 Wetland 0.99 Watershed health 0.90 Standard watershed Watershed health index (Sub-index 1 + Sub-index Sub-index x) Total number of sub-indices Ref.) EPA 2012, Identifying and Protecting Healthy Watersheds Habitat connectivity 0.46 Wetland 0.34 Watershed health 0.28 (0) Watershed health (1)

19 Biological Condition 19 TDI (Trophic Diatom Index) BMI (Benthic Macroinvertebrate Index) FAI (Fish Assessment Index) (a) (b) (c) TDI BMI FAI A (Poor) 0 ~<30 A (Poor) 0 ~<45 A (Poor) 0 ~<25 B (Fair) 30 ~<45 B (Fair) 45 ~<60 B (Fair) 25 ~<56.2 C (Good) 45 ~<60 D (Best) 60 ~ 100 C (Good) 60 ~<80 D (Best) 80 ~ 100 C (Good) 56.2 ~<87.5 D (Best) 87.5 ~ 100

20 Biological Condition 20 Watershed health index (biological condition) 6 years ( ) observed data Normalized sub-index TDI BMI FAI Watershed health index Multipurpose & Hydroelectric Dam Normalized component value Sub-index Observed value for watershed Reference value in watershed (Normalized value 1 + Normalized value Normalized value x) Total number of normalized values Standard watershed TDI 0.70 BMI 0.98 FAI 0.92 Watershed health 0.91 Standard watershed Watershed health index (Sub-index 1 + Sub-index Sub-index x) Total number of sub-indices Ref.) EPA 2012, Identifying and Protecting Healthy Watersheds TDI 0.69 BMI 0.98 FAI 0.72 Watershed health 0.83 (0) Watershed health (1)

21 Watershed Health 21 Landscape Stream geomorphology Integrated Watershed Health Index Standard watershed 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 Hydrology Water Quality No data Standard watershed 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 Aquatic habitat condition Biological condition Standard watershed 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 Multipurpose & Hydroelectric Dam (0) Watershed health (1)

22 Impervious Area Change 22 Vulnerability index (Impervious area change) Normalized sub-index Impervious area (2008) Impervious area (2050 by CLUEs) Impervious area change (2008 vs. 2050) Watershed vulnerability index Multipurpose & Hydroelectric Dam Normalized component value Sub-index Impervious area in Impervious area in 2008 Impervious area in 2008 (Normalized value 1 + Normalized value Normalized value x) Total number of normalized values Standard watershed Impervious area change 0.00 Watershed vulnerability 0.00 Watershed vulnerability index (Sub-index 1 + Sub-index Sub-index x) Total number of sub-indices Ref.) EPA 2012, Identifying and Protecting Healthy Watersheds Standard watershed Impervious area change 0.68 Watershed vulnerability 0.68 (0) Watershed vulnerability (1)

23 Climate Change 23 Vulnerability index (Climate change) Normalized sub-index Baseline ( ) vs. HadGEM2-AO RCP 8.5 (2050s) Precipitation change Max. temperature change Min. temperature change Watershed vulnerability index Multipurpose & Hydroelectric Dam Normalized component value Sub-index Watershed vulnerability index Avg. annual precip. in 2050s under the RCP scenario - Avg. annual precip. for baseline ( ) (Normalized value 1 + Normalized value Normalized value x) Total number of normalized values (Sub-index 1 + Sub-index Sub-index x) Total number of sub-indices Ref.) EPA 2012, Identifying and Protecting Healthy Watersheds Standard watershed Precipitation change 0.39 Max. temperature change 0.62 Min. temperature change 0.64 Watershed vulnerability 0.40 Standard watershed Precipitation change 0.98 Max. temperature change 0.73 Min. temperature change 0.78 Watershed vulnerability 0.95 (0) Watershed vulnerability (1)

24 Water Use Change 24 Vulnerability index (Water use change) Normalized sub-index Domestic water use change Industrial water use change Agricultural water use change Watershed vulnerability index Multipurpose & Hydroelectric Dam Normalized component value Sub-index Water use in Water use in 2006 Water use in 2006 (Normalized value 1 + Normalized value Normalized value x) Total number of normalized values Standard watershed Domestic water use change 0.17 Industrial water use change 0.26 Agricultural water use change 0.35 Watershed vulnerability 0.22 Standard watershed Watershed vulnerability index (Sub-index 1 + Sub-index Sub-index x) Total number of sub-indices Ref.) EPA 2012, Identifying and Protecting Healthy Watersheds Domestic water use change 0.15 Industrial water use change 0.39 Agricultural water use change 0.57 Watershed vulnerability 0.28 (0) Watershed vulnerability (1)

25 Recent Land Cover Change 25 Vulnerability index (Recent land cover change) Normalized sub-index Anthropogenic land cover (2008) Anthropogenic land cover (2014) Recent land cover change (2008 vs. 2014) Watershed vulnerability index Multipurpose & Hydroelectric Dam Normalized component value Anthropogenic land cover in Anthropogenic land cover in 2008 Anthropogenic land cover in 2008 Standard watershed Sub-index (Normalized value 1 + Normalized value Normalized value x) Total number of normalized values Recent land cover change 0.36 Watershed vulnerability 0.36 Watershed vulnerability index (Sub-index 1 + Sub-index Sub-index x) Total number of sub-indices Ref.) EPA 2012, Identifying and Protecting Healthy Watersheds Standard watershed Recent land cover change 0.79 Watershed vulnerability 0.79 (0) Watershed vulnerability (1)

26 Watershed Vulnerability 26 Impervious land cover change No data Climate change Watershed Vulnerability Index Standard watershed 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 Impervious area change 0.68 Climate change 0.95 Water use change 0.28 Recent land cover change 0.79 Integrated vulnerability 0.86 Water use change Recent land cover change Standard watershed Impervious area change 0.00 Climate change 0.15 Water use change 0.70 Recent land cover change 0.15 Integrated vulnerability 0.20 Multipurpose & Hydroelectric Dam Watershed vulnerability (0) (1)

27 Social Context 27 Normalized sub-index Financial independence rate GRDP (gross regional domestic product ) Water management public officer Social Context Index Multipurpose & Hydroelectric Dam Normalized component value Sub-index Observed value of watershed Maximum value for all watersheds (Normalized value 1 + Normalized value Normalized value x) Total number of normalized values Standard watershed Financial independence rate 0.18 GRDP 0.47 WM public officer 0.29 Social context 0.18 Standard watershed Watershed vulnerability index (Sub-index 1 + Sub-index Sub-index x) Total number of sub-indices Ref.) EPA 2012, Identifying and Protecting Healthy Watersheds Financial independence rate 0.22 GRDP 0.27 WM public officer 0.33 Social context 0.23 (0) Social context (1)

28 Integrated Capacity Indicator Summary Scores Watershed Health Resilience + Priority 28 (a) Watershed resilience analysis (Recovery potential) (b) Priorities matrix for setting protection and restoration priorities Zone A Zone B Zone A Zone B Pass Protect Protection Priority Fail Restoration Priority Site-specific Determination Restore Zone D Zone C Zone D Zone C Stressor Indicator Summary Scores * Circle size increases with social context summary score value Vulnerability Ref.) (Norton et al., 2009, A Method for Comparative Analysis of Recovery Potential in Impaired Waters Restoration Planning. Environmental Management 44: Ref.) U.S. EPA. 2012, Identifying and Protecting Healthy Watersheds: Concepts, Assessments, and Management Approaches. EPA 841-B

29 Resilience (Recovery Potential) 29 Integrated capacity indicator summary scores (Health) Stressor indicator summary scores (Vulnerability) Social context summary scores Watershed Resilience Analysis Cluster Analysis Medium Integrated (hydrological + water quality + ecological) Han river basin Medium Multipurpose & Hydroelectric Dam

30 Protection and Restoration Priority 30 Integrated Watershed Health Index Zone A Integrated Watershed Vulnerability Index A B C D Protect Protection Priority Restore Restoration Priority Zone BD Protection and Restoration Priorities Protect Protection Priority Restore Restoration Priority Zone BD Zone C Multipurpose & Hydroelectric Dam

31 Resilience + Priority 31 Watershed Resilience Analysis Medium Protection and Restoration Priorities Protect Protection Priority (a) (b) Restore (c) Restoration Priority Resilience + Restoration Priorities Restore Restoration Priority Resilience ( medium) Multipurpose & Hydroelectric Dam

32 Summary and Conclusions 32 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.

33 Thank you Earth Information Engineering Lab. So Ra AHN Dept. of Civil and Environmental System Engineering Konkuk University, Seoul, South Korea Phone: Web: