Strengthening Adaptive Capacity of Water Supply Systems to Climate Change - the Danshuei River Watershed

Transcription

1 Strengthening Adaptive Capacity of Water Supply Systems to Climate Change - the Danshuei River Watershed Prof. Ching-pin Tung ( 童慶斌 ) National Taiwan University Prof. Pao-shan YU ( 游保杉 ) Hydraulic and Ocean Engineering National Cheng Kung University Prof. Ming-hsu Li ( 李明旭 ) Institute of Hydrological and Oceanic Sciences National Central University

2 Contents Background and Goals Analysis of Current Hydrology Assessment of Climate Change Impacts Adaptations Final Remarks

3 Background Extensive development requires more resources and discharges more pollutants, which may degrade eco-environment. Sustainable development requires to meet the needs of both current and future generations. Development of sustainable watershed management plans is crucial, and changing climate is the most important challenge and should be seriously considered.

4 Water resources engineering is designed according to physical rules and statistic information derived from historical observation. Those statistics are assumed to be constant in design process.

5 Climate not only changes but also is changing. Can hydrological statistics be constants? Can water resources systems still provide reliable services in future? How and what should we do?

6 Goals of our study Evaluating the reliability of water supply systems. Identifying effective strategies to strengthen adaptive capacity of water supply systems, which can Continuously support social and economic developments and Sustainably conserve eco-environment

7 Study Area - the Dan-Shuei River Watershed Sindian River Keelung River Dahan River Shih-Men Reservoir Fei-Tsui Reservoir Three major Tributaries Sindian River Dahan River Keelung River Two reservoirs Shih-Men Reservoir Fei-Tsui Reservoir

8 Sansia River (Dahan River) Keelung River Shih-Men Reservoir Banxin District Taoyuan District Keelung District Taipei District Dahan River Fei-Tsui Reservoir Sindian River (Figures provided Bioenvironmental by Prof. Li) Systems Engineering

9 Analysis of Current Hydrology

10 Trend of Rainfall Intensity [Prof. Li ( 李明旭 ), NCU] 30 Rainfall Intensity 35 Rainfall Intensity 25 Linear Fit y = x Linear Fit y = x ) y a /d 20 m ( m s ity n 15 te I n l f a 10 in a R 5 0 淡水站 Year ) 25 y a /d m ( m 20 ity s n te I n 15 l f a in a R 基隆站 Year 30 Rainfall Intensity Linear Fit 25 y = x ) y a /d 20 m ( m s ity n 15 te I n l f a in 10 a R Year 台北站 50 Rainfall Intensity 45 Linear Fit y = x ) y a 35 /d 30 m ( m s ity n 25 te I n l 20 f a in a 15 R Year 竹子湖站

11 Trend of Dry Day durations average Linear Fit y = x average Linear Fit y = x s y a D 4 s y a D Year Year Taipei Dansheui

12 Trend of flow/rainfall ratio Fei-Tsui Reservoir [Prof. Li ( 李明旭 李明旭 ), NCU] Q/P Linear Fit A nnual Q /P A nom aly 集水區雨量站之相關位置圖 D epth (m m ) Year 集水區年逕流比值距平圖 Rainfall Rainfall STD Year 集水區年降雨深度與年逕流深度歷線圖

13 Assessment of Climate Change Impacts

14 Methodology Development of systematic tools to identify vulnerable components of water supply systems Natural components Atmosphere - climate and weather Hydrosphere - Stream flows, groundwater Human components Facility reservoirs, treatment plants, distribution systems Management plans demands and operations

15 KY05 KY06 TO11 KY04 # # TO09 KY03 KY02 TO08 KY01 TO07 TO10 # TO06 # TO01 TO03 TO02 TO04 TO05 數個擬模減增量流 Procedures GCM Predictions Impact Inoformation for Decision Making 短期中期長期 氣候預設情境 Downscaling W N S E SiChou TouChen ChuLin RuiFeng Future Climate Scenarios Water Supply System Dynamics Model <the tendays of year> FeiCui Rule A FeiCui Rule B FeiCui Rule C <ZhiTan Total Supply> <QinTan Total Supply> FeiCui Power Station FeiCui Volume Depth FeiCui Reservoir Operation Rules Flow ZhiTan Aqueduct Max Capacity QinTan Aqueduct Max Capacity ZhiTan WTP Max Capacity ZhiTan Supply QinTan Supply QinTan WTP Max Capacity FeiCui Reservoir ZhiTan Dam QinTan Weir BeiShi river 1 FeiCui Rule Flow FeiCui Overflow B point 1 NanShi river XinDian river 1 XinDian river 2 ZhiTan Dam Overflow B point 2 QinTan Weir Overflow FeiCui Reservoir Volume Max ZhiTan Dam Volume Depth XinDian river 3 QinTan Weir Side flow ZhiTan Dam Max Volume QinTan Weir <NanShi river> volume depth QinTan Weir Max Volume FeiCui Reservoir flow <BeiShi river 1> Km Weather Generation Hydrological Model

16 Downscaling Methods Simple Downscaling Climate changes of a local area are assumed the same as the nearest grid point Statistical Downscaling Finding the statistical relationships between regional climate and local climate.

17 Future Climate Scenarios Simple Downscaling SDSM GCMs CGCM2 ECHAM4 HADCM3 CCSR/NIES R30(GFDL) CSIRO-Mk2 HADCM3 SRES A2 B2 A2 B2

18 Impacts on Stream Flows [Prof. Yu ( 游保杉 ), NCKU]

19 HBV Model Parameters FC(Field Capacity) β LP (Parameter) UZL(Outflow height) Recession Coefficient K 0 (UZL) K 1 (upper tank) K 2 (lower tank) Ce (coefficient of ET) PERC (Percolation) Q 0 =K 0 (S uz -UZL) Quick response Runoff(Q) Q 1 =K 1 S uz Q d =K 2 S lz Rainfall Evapotranspiration Slow response Q s UZL PERC S sm S uz S lz Soil moisture Upper response tank Lower response tank

20 Impacts on Stream Flows Dry Period [Prof. Yu ( 游保杉 游保杉 ), NCKU] Fei-Tsui Reservoir Inflows Scenarios A2 B2 Simulation Scenarios HAD3_A2 HAD3_B2 Simulation Flow ( mm/day ) 12 8 Flow ( mm/day ) (%) Simple Downscaling (%) SDSM Downscaling

21 Impacts on Stream Flows Wet Period [Prof. Yu ( 游保杉 游保杉 ), NCKU] Keelung river Scenarios A2 B2 Simulation Scenarios HAD3_A2 HAD3_B2 Simulation Flow ( mm/day ) 20 Flow ( mm/day ) (%) Simple Downscaling (%) SDSM Downscaling

22 Impacts on Reservoir (C.P. Tung) ( 圖片來源 : 水利署十河局網站 ) 圖片來源 : 海洋大學河海工程系

23 Water Supply Flood Mitigation ) 尺公方立萬 ( 百量水蓄 下限蓄水量嚴重下限蓄水量 25percentile average 75percentile ) 尺 ( 公 244 位水 242 庫水 壩頂標高操作上可容忍的高度 HAD_A2_ 短期 HAD_A2_ 中期 HAD_B2_ 短期 HAD_B2_ 中期 HADCM3_A2_ 短期 HADCM3_A2_ 中期 HADCM3_B2_ 短期 HADCM3_B2_ 中期 月份 小時 Less space for flood mitigation More Active Storage? More space for flood mitigation Less Active Storage

24 Modifications of Operational Rules due to More Extreme Events_HADCM3

25 Impacts on Water Supply (C.P. Tung) Dahan River Shih-Men Reservoir Keelung River Sindian River Fei-Tsui Reservoir

26 Water Supply System Dynamics Model - the Sindian and Dahan River River Channel Beishie Feitsui Reservoir Chih-Tan Dam Nanshie Sansia River Dahan Shihmen Reservoir Hou-Chiu Weir Agriculture Shihmen Canal Taoyuan Canal Ching-tan Dam Sansia Weir Yuan- Shan Weir Taoyuan District Taipei District Banxin District

27 Water Supply System Dynamics Model - the Sindian and Dahan River Treatment Plant River Channel Withdraw Ditch Beishie Feitsui Reservoir Chih-Tan Chih-Tan Dam Changshin Ching-tan Dam Gungkuan Nanshie Sansia River Sansia Weir Dahan Shihmen Reservoir Hou-Chiu Weir Yuan- Shan Weir Lungtan Danan Banxin Pingzheng Shihmen Taoyuan District Agriculture Shihmen Canal Taoyuan Canal Taipei District Banxin District

28 The Sindian Water Supply System Dynamics Model CT 4th capacity CT 5th-add capacity CH Max Capacity CT Max Capacity Chang-Hsing WTP <Total Water Demand> CT Aqueduct Capacity Nan Chih-Tan WTP <Total Water Demand> separate point Kung-Kuan WTP <Chih-Tan WTP> overflow Aqueduct Aqueduct Capacity KK Max Capacity Pei Fei-Tsui Reservoir combined point Chih-Tan Dam Ching-Tan Weir volume-depth Pei-Shih River downstream Hsin-Tien River upstream Hsin-Tien River Hsin-Tien River downstream Power Station Operation Rules: water to dilute pollution delay <Total Water Demand> Rule-up Rule-down Rule-down seriously <Nan> <volume-depth> <days of year>

29 Keelung Water Supply System Dynamics Model <NN4> <Proportion of CF WTP Responsibility> <CF Max Capacity> point 3.6 ChungFu WTP <Proportion of AL WTP Responsibility> <AL Max Capacity> AnLe WTP abstraction NN4 NN4 Max Capacity MaSu River 1 HsinShan Reservoir MaSu inflow MaSu River2 HsinShan WTP YJ River YuJui Weir KangHao Keng Weir KHK River 1 <JF Max Capacity> ChiLung River 1 point3.1 JuiFang WTP ChiLung River 2 <Proportion of JF WTP Responsibility> point 3.7 <PT tendays MaSu River3 water right> PT Max AnLe Capacity abstraction <Proportion of HS WTP Responsibility> <Proportion of CH WTP Responsibility> KHK inflow YJ inflow <Proportion of PY WTP Responsibility> PaTu abstraction TaWuLun River <HS Max Capacity> YJ water right YJ overflow abstraction CH1 CH1 Max Capacity KHK River 2 PaiYun WTP YJ tendays water right <PY Max Capacity> point3.3 point 3.4 point 3.5 point3.6 point 3.9 point 3.10 ChiLung River 3 ChiLung River 4 point 3.11 point 3.12 Chilung River 5 ChiLung River 6 ChiLung River 7 ChiLung River 8 ChiLung River 9 ChiLung River 10 ChiLung inflow TSK overflow NuanNuan River NN3 Max Capacity TungShih Keng Weir point3.2 MLK overflow MaLing Keng Weir MLK water right TSK River abstraction NN2 TSK water right TSK tendays water right TSK inflow HS water right HS overflow MLK River PCK water right PaoChang Keng Weir PCK River PCK overflow abstraction NN1 Max Capacity PT tendays water right abstraction NN3 <abstraction NN4 NN1> <abstraction NN2> <Proportion of NN WTP Responsibility> MLK tendays water right <the? month of year> PCK tendays water right MLK inflow S overflow LiuTu WTP <LT Max Capacity> <Proportion of LT WTP Responsibility> PCK inflow CH2 CH2 Max <abstraction Capacity CH1> <Proportion of CH WTP Responsibility> <Proportion of NN WTP Responsibility> HsiShih Reservoir KungLiao Weir abstraction NN1 Shuang River NN2 Max Capacity <the? month of year> HS inflow S water right HS River S inflow <Proportion of KL WTP Responsibility> <KL Max Capacity> KungLiao WTP S tendays water right <the? month of year>

30 Current Water Supply Capability (1991~2001, unit: 10 4 CMD) W/O Ban I Project W/ Ban I Project District Demand Supply Demand Supply Taipei ( 支援板新 支援板新 ) Banxin ( 臺北支援 臺北支援 ) Taoyuan Keelung

31 Trend of Water Supply Capacity SRES-A2-Simple Downscaling %~-5% -5%~-10% <-10% 0~5% 5%~10% >10% -6 Taipei 台北 Banxin 板新 Taoyuan 桃園 Keelung 基隆

32 Trend of Water Supply Capacity SRES-B2-Simple Downscaling %~-5% -5%~-10% <-10% 0~5% 5%~10% >10% -6 Taipei Banxin Taoyuan Keelung

33 Trend of Water Supply Capacity SRES-A2-SDSM Downscaling SDSM 降尺度 A2 情境環境承載力變化趨勢 台北板新桃園基隆 0%~-5% -5%~-10% <-10% 0~5% 5%~10% >10%

34 Trend of Water Supply Capacity SRES-B2-SDSM Downscaling 6 SDSM 降尺度 B2 情境環境承載力變化趨勢 %~-5% -5%~-10% <-10% 0~5% 5%~10% >10% -6 台北板新桃園基隆

35 Ability to Meet Water Demand The Taipei District Water supply for the Taipei is still sufficient for next 20~30 years, and it can deliver extra water to other districts. The Banxin District The ability of water supply of the Banxin district may decrease due to reduced streamflows in dry periods. Water delivered from the Taipei district will be a very important strategy.

36 The Taoyuan district Water supply may decrease due to lower flows in dry periods. Water demand increases significantly, which causes more water shortage. Water demand management is very important. More water sources and new facility may also be required for the district.

37 The Keelung District Although the ability of water supply may increase in the Keelung district, significant increase of demand may still result in water deficit. Currently, the utilization rate of the Keelung river is still low, more water treatment facility could be installed to increase water supply.

38 Adaptations

39 Principles to Strengthen Adaptive Strategies Identify the most vulnerable components and their corresponding strategies. Insufficient water resources? Less flexible water management plan? Too many water demands? Develop an early warning systems to trigger actions.

40 Key points on Strengthening Adaptive Capacity of Water Supply Systems Demand Management Water Saving Land Planning Water Management Ability Connecting different systems Natural conservation New Water Sources & Facility Groundwater Rainfall Harvesting New Treatment Facility

41 Early Warning Systems to Strengthen Adaptive Capacity (a) Shortage Warning (b) (c) Adaptative Capacity Adaptative Capacity Action Warning Adaptative Capacity High Vulnerability time Strengthen Adaptive Capacity time Reduce Demand time

42 Early Warning and Risk Management Systems Systems Time Scale Responses Real time Hourly, Daily Operational Measures Seasonal Season, Half year Management Near-term Several years Management Long-term Ten years Planning Management

43 Long-term Planning Adaptations to Changing Climate Ranking Adaptation Strategies

44 Decision making on Adaptation Actions Taking actions depends on several factors, including (1)Time left to take action, (2)Uncertainty, (3)Effectiveness in reducing risk & vulnerability, (4)Costs (regret or non-regret) Action = F(T, U, E, C) Ranking Tool: Analytic Hierarchy Process

45 Example of AHP Analysis GOAL Ranking Adaptive Strategies in Taoyuan Cost-Benefit Time Principle Effectiveness Uncertainty No-Regret Justice Vulnerability Reversable Ta-Han River Southern Re-allocation (SRA) Alternative Lung-Tan Water Desalination Plant Treatment Plant (DP) Expansion(WTPE) 45

46 Results Weightings of all Principles Cost-Benefit Time Effectiveness Uncertainty Weightings of all Alternatives SRA WTPE DP Cost-Benefit Time Effectiveness Uncertainty Ranking SRA WTPE DP Lung-Tan Water Treatment Plant Expansion (WTPE) is the best of the three assessed Adaptative strategies in Taoyuan. 46

47

48 Functions Analyzing historical hydrological data Preparing climate scenarios (10 GCMs and 3 SRES scenarios) Generate daily weather data Simulate impacts on stream flows (the HBV and GWLF models) Simulate Impacts on water supply systems (Link to a pre-developed system dynamics model, VENSIM) Rank adaptation strategies (Analytic Hierarchy Process)

49 Initial Setting

50 Weather Generator

51 HBV MODEL

52 More functions will be added Better statistical downscaling methods Better impact simulation on water resource systems Agricultural Water Demands Groundwater Rainfall Harvesting Systems Water Quality Better water resources management tools Conjunction uses of surface and ground water Modification on reservoir operational rules

53 Seasonal Forecasts and Responses to Climate Variability 1. Forecasts on water demand and supply 2. More flexible management strategies

54 Seasonal Climate Forecasts Streamflow Irrigation Demand Groundwater Reservoir Level Beginning time Ending time

55 Seasonal Storage Forecasts - January, February, March (JFM, 2002) 上限下限嚴重下限預測低水位預測高水位 蓄水量 ( 千立方公尺 ) 旬

56 Seasonal Storage Forecasts - February, March, April (FMA, 2002) 上限下限嚴重下限預測低水位預測高水位 蓄水量 ( 千立方公尺 ) 旬

57 Seasonal Storage Forecasts - March, April, May (MAM, 2002) 上限下限嚴重下限預測低水位預測高水位 蓄水量 ( 千立方公尺 ) 旬

58

59 Benefits of Applying Seasonal Information Actual Estimate Year Stop Farming Area (ha) Money paid to Farmers (100 Million) Stop Farming Area (ha) Money paid to Farmers (100 Million) Benefits (100 Million) ,439(3 月休耕 ) 4,700(5 月休耕 ) 11.8 (11.3) 10, ( +3.6) , (10.6) case (+10.6) case ( +6.4) , (27.9) 21, (+15.2) , (13.8) (+13.8) B/C = NT$4,960,000,000/NT$285,000 = 17,403 Total: +55.6(+49.6)

60 Final Remarks Sustainable uses of water resources is our goal. The abilities to evaluate climate change and to strengthen adaptive capacity are very important to reach the goal. Uncertainty is the major constraint on taking actions. Early warning and risk management systems are very important for adapting to future climate.

61 Thanks for Listening! All Questions are Welcomed! Ching-pin Tung ( 童慶斌 ) cptung@ntu.edu.tw