Data challenges in Trans-boundary River Basins: Case Study of the Upper Indus Basin

Transcription

1 Data challenges in Trans-boundary River Basins: Case Study of the Upper Indus Basin Asif Khan Lead Author (Water chapter- AR6 IPCC) Post Doctorate (Water-Energy-Food-Climate Change, IIASA, Austria) PhD (Water and Climate Change, Cambridge University, UK)

2 Academics: PhD in Water and Climate PGS in GIS and RS EMBA Project Management B.Sc Civil Engineering

3 Work Experience: NESPAK (Site cum Design Engineer) Irrigation and Hydle Department, Khyber Pakhtunkhwa (SDO) FATA Secretariat (Deputy Director Technical) Asian Development Bank (Hydraulic Design Engineer and Climate Change Expert) University of Cambridge (Graduate Supervisor) IIASA, Austria (Research Associate) UET, Peshawar (Assistant Professor) LUMS, WIT, Lahore (Research Director)

4 Current/Past Research:

5 Outline o o o o o o Global Problems Potential and problems related to the Indus Basin Case study of the Upper Indus Basin Hydrological modelling improvement needs Conclusions and Recommendations Questions and Answers

6 Global challenges o Population growth o Global warming and climate change Source: UN: facts and trends (2006) Increased population will need more: i) water supply, ii) food production, iii) energy production/supply, iv) flood and drought mitigation, v) urbanization, and v) industrial development

7 Global challenges o o Population growth Global warming and climate change Global mean surface temperature increased by / C during , while projected expected increase is 1.4 to 5.8 C during 1990 to 2100 (IPCC 2007, 2013) Global warming is causing glacier retreat, Severity in floods and droughts, Increasing water scarcity, Increasing slope instability and landslides, Increasing Glacier Lake Outburst Floods (GLOFs) Reservoir sedimentation, Forest fires, and Increasing water losses/evapotranspiration Source: (Inman 2010) Adverse impact on Eco-system

8 The Indus Basin

9 The Indus Basin The Indus Basin originates from the Hindukush- Karakoram- Himalaya and Tibetan Plateau (HKH-TP) region, and runs from the north to south.

10 The Indus Basin The Indus Basin Irrigation System (IBIS) is one of the largest in the world Fulfills ~ 90% of the irrigation needs Cater for > 33% of energy needs (mostly in Pakistan) More than 56-70% of Pakistan and India s population is dependent on agriculture Agriculture contribute ~24% in annual GDP of Pakistan

11 Snow- and Glacier-melt runoff modelling

12 Water: water scarcity

13 Hydro-power potential in the Indus Basin The potential hydropower in the Indus Basin (within Pakistan) is 60,158 MW. The potential hydropower in the Indus Basin (within India) is about 50% compared to Pakistan, although India s current installed capacity is more than Pakistan Of the available potential, only 6,750 MW is installed, ~1,735 is under construction, while 19,353 MW is under planning in Pakistan

14 Hydro-power potential in the Indus Basin More than 22 hydro-power projects are planned/under-construction in the UIB (PPIB, 2011)

15 Issues/Problems Asian temperature rise is greater than world s average temperature rise (IPCC 2013) According to CMIP 5, under the RCP 4.5, the expected temperature rise is about 2 o C (relative to ) in the whole HKH during , The HKH-TP region has a glacier area of about 33,000 km 2 (ICIMOD, 2009) and contains about 12,000 km 3 of freshwater (IPCC, 2013) Glaciers in the western Himalayas, Hindukush, and eastern Karakoram are losing mass at a high rate (Kaab et al., 2012, 2015, Gardelle et al., 2012, 2013) Glaciers in the western Karakoram are advancing and bear slightly negative mass balance during the last decade (Kaab et al., 2012, 2015; Gardelle et al., 2012, 2013) Monsoon precipitation became more intense and frequent in the last four decades, and is responsible for floods in the region (Wang et al., 2011)

16 Issues/Problems Snow- and glacier-melt contributes more than 80% in stream flows in various subbasins of the Indus Basin Any change in temperature or snow-fall or snow-/glacier-melt will cause significant ramification on downstream water resources Land sliding and floods may affect existing and ongoing projects, such as Pak-China economic corridor Historic civilization in the northern Indus basin is under threat due to floods, and proposed reservoirs There are more than 1800 glacial lakes, of which >50 are potentially dangerous (Campbell, 2005)

17 Issues/Problems: Sedimentation Sedimentation at Tarbela Dam (Ali and Deboer, 2007) Tarbela Dam lost ~31% of storage capacity during , Mangla Dam lost ~ 18% ( ), Chashma barrage lost 51% during Sedimentation will rise with increase in snow and glacier melt

18 Hydrological Modelling Constraints in the Upper Indus Basin

19 Constraints: variability in modelled flows

20 Constraints: variability in flow components Hunza basin (Karakoram) Astore basin (Himalayas)

21 Constraints: potential causes Use of different hydrological models Use of different time period data Use of different input datasets Basin Boundaries Precipitation Datasets Snow-cover Datasets Glacier-cover Datasets Snow and ice-melt parameters Calibration Parameters

22 Use of biased basin boundaries: UIB1 is ~172,173 km 2. UIB2 is ~205,000 km 2 UIB2 is ~266,000 km 2 UIB 2 and 3 are biased overestimated boundaries Most hydrological modelling studies have used overestimated basin boundaries (UIB 2 & 3) for the UIB.

23 Main cause of inaccurate basin delineation Station Elevation in the original SRTM DEM (m) Critical Point 1a 4,253 Critical Point 1b 4,248 Critical Point 1c 4,275 Critical Point 1d 4,270 Pangong Lake Water level 4,241 (For details see: Khan et al., 2014) Beach Ridges (4,265m) are an evidence of Pangong Tso lake to be remained part of the UIB about 1,000 years ago, and current warming climate and melt-increment induces increment of water-surface level at a rate of about m per decade (Song et al., 2013; Khan et al., 2014)

24 Uncertainty in estimated basin areas

25 Potential Causes: use of different precipitation datasets

26 Climate stations density in gridded precipitation datasets Climatic stations density in APHRODITE data based on number of stations in 0.05 o grid Climatic stations density in CRU TS 3.1 data based on number of stations in 0.5 o grid

27 Precipitation datasets accuracy assessment

28 Precipitation datasets accuracy assessment

29 ISI-MIP precipitation and modelled flow

30 Uncertainty in existing studies

31 Snowmelt runoff modelling

32 Use of biased melt rates: Clean ice varies between 30-35% of total glacier area in various basins Available hydrological modelling studies adopted uniform ice melt rates for the entire glacier areas In addition whole of debris cover has been assumed to be thick *means seasonal, perennial snow and snow-covered ice

33 ISI-MIP precipitation and modelled flow

34 ISI-MIP precipitation and modelled flow

35 Climate stations density in gridded precipitation datasets Climatic stations density in APHRODITE data based on number of stations in 0.05 o grid Climatic stations density in CRU TS 3.1 data based on number of stations in 0.5 o grid

36 Modelled monthly flows (ISI-MIP)

37 Use of underestimated snow-cover: MODIS snow cover data cannot capture debriscovered ice

38 Use of underestimated snow-cover: MODIS snow cover data cannot capture small glaciers

39 Use of overestimated glacier areas:

40 Use of overestimated glacier areas:

41 ISI-MIP water scarcity

42 FAO water scarcity

43

44 Implications Ill informed modelling and planning Reshun HPS Chitral

45 Conclusions and Recommendations Input hydro-climate datasets are partly biased due to non-availability, nonaccessibility and non-sharing of trans-boundary hydro-climate datasets Almost all available hydrological modelling studies have encountered significant biases due to use of overestimated basin areas, underestimated precipitation, underestimated snow area, overestimated glacier areas, use of biased melt rates, and other biased calibration parameters; There is need of precise and accurate hydro-climatic modelling, and identification of best available datasets and techniques suitable for the UIB; Use of improved hydro-climate modelling is need of the time

46 Animation source:

47 Any Animation source: