Presentation for BHS SWS / CIWEM - hydrology · Presentation for BHS SWS / CIWEM Climate Change and Hydrology: A Regional to Global Perspective – University of Exeter, Wednesday

Presentation for BHS SWS / CIWEM

Climate Change and Hydrology: A Regional to Global Perspective – University of Exeter,

Wednesday 6th July 2011

By Bernd R Eggen, PhD

Climate change specialist for ADB project

“Support for the National Action Plan on Climate Change”

06/Jul/2011 Bernd R Eggen 1

Climate Change Impacts on Irrigation in India

Findings from an Asian Development Bank Funded TA Project 7417

Overview

• Introduction to some climatological features

• Projected climate change affecting India

• TA 7417’s wider setting – National Water Mission

• Findings for the 3 river basins

• Recommendations


Some facts about India …



• Land area size: 3,287,263 km2

• Population est. at 1.2 billion



The biggest major rivers of India are:


Arabian Sea: Indus, Narmada, Tapti

Bay of Bengal: Brahmaputra, Ganges (with its tributaries Yamuna, Kameika, Gomti, Chambal), Meghna, Mahanadi, Godavari, Krishna, Kaveri (Cauvery)

Weather / Climate in India …

3 seasons:

“cold season” / winter

“hot” / pre-monsoon

“monsoon”



Temperatures & Rainfall

Example: Delhi

…. similar yearly total to UK, but almost all rain falls in June – September



IMD - Long Range Forecast Update for 2011 Southwest Monsoon Rainfall

• “IMD’s long range forecast for the 2011 south-west monsoon season (June to September) is that the rainfall for the country as a whole is most likely to be Normal (96-104% of Long Period Average (LPA)). There is very low probability for season rainfall to be deficient (below 90% of LPA) or excess (above 110% of LPA). Quantitatively, monsoon season rainfall is likely to be 98% of the LPA with a model error of ± 5%. The LPA of the season rainfall over the country as a whole for the period 1951-2000 is 89 cm.” [IMD, 19th April 2011]


Stability of Monsoon


Some really intense cloudbursts

World's record point rainfall values for various durations

24hrs 314.4mm Seathwaite, Cumbria 19/20 Nov 2009 – “UK record for a

single location in any given 24-hour period” (Met Office)

24hrs 994mm Mumbai and wider area of Maharashtra State 26 July 2005

Duration

Depth (mm) Location Date

1min 38 Barot, Guadeloupe 26 Nov 1970

5min 62 Port Bells, Panama 29 Nov 1911

8min 126 Füssen, Bavaria 25 May 1920

15min 198 Plumb Point, Jamaica 12 May 1916

13 Bernd R Eggen 06/Jul/2011

Changes in Rainfall Intensity


Heavy rainfall events are becoming more common R>100mm/day & R>150mm/day Goswami et al, 2006 - DOI:10.1126/science.1132027

Monsoon: Too much, too little

Bernd R Eggen 15

2011: Sri Lanka 2010: Floods Pakistan 2010: Cloudburst Leh 2005: Floods Mumbai 2002: Crop failure 1997: Crop failure 1876-78: Famine

06/Jul/2011

Model Orography – GCM vs RCM


Precipitation – GCM / Obs / RCM


A detailed study of all GCMs used for IPCC AR4 (CMIP-3) ensemble showed that a number of GCMs did not reproduce either quantity or quality (or both) of SW Monsoon.

River Basins vs RCM Grid


06/Jul/2011 19

Soil and Water Assessment Tool

i. Preparation of PRECIS precipitation data, comparison of statistics of PRECIS baseline precipitation with those of the observed gridded data sets (IMD, APHRODITE);

ii. Preparation of PRECIS temperature (T) and Eto (Evapotranspiration) data and comparisons of statistics of PRECIS baseline T data with those of observed series;

iii. SWAT model calibrations on Satluj, upstream of Bhakra reservoir; iv. SWAT model production runs on all three basins; v. Assessment of climate impacts on glacial melt in the Satluj;

vi. Water balance studies to investigate alternative water management

and cropping strategies that permit sustainable water use (surface and groundwater) for a selected distributary in the Sirhind command (about 10,000ha).



http://gisserver.civil.iitd.ac.in/natcom/ for live site

TA 7417 – Preliminary Findings

Technical Assistance to Support the National Water Mission of NAPCC has been developed following a request from the Department of Economic Affairs (DEA) on behalf of MoWR for ADB to assist towards the preparation of specific studies which would help to operationalise the National Water Mission (NWM) of the NAPCC.

Central Water Commission (CWC) additional key stakeholder.


Satluj Basin (Punjab)

• Water mainly from glacial & snow melt

• Extensive canal system & reservoirs

• Dams may increase adaptive potential

(especially Bhakra Dam)

Bernd R Eggen 23 06/Jul/2011

Projected Changes – Temp & Rain

Top map:

CC to

2050s;

below:

CC to

2090s

Baseline

1961-90

Bernd R Eggen 24

Tair Precip

06/Jul/2011

Chambal Basin (Central India)

• Over-usage of ground water

• Race to drill ever deeper wells

• Some communities set land aside for “recharge” ponds


Regional Climate Modelling


Cauvery* Delta (Tamil Nadu)

Bernd R Eggen 27

*Kaveri - Low lying & flat delta region threatened by sea level rise and saline intrusion

Crop yields (paddy) & harvest frequencies reduced; brackish water is drained out of delta

06/Jul/2011

Sea Level Change

Bernd R Eggen 28

• Sea level rise impacts on

surface and groundwater

and increases flood risk

• Interaction of extreme

events (cyclones &

tsunamis with sea level

rise)

06/Jul/2011

Overall CCA Conclusions

• 3 sub basins facing different risks from CC, exacerbating existing pressures

• Detailed strategic frameworks have been developed for each situation & India Water Systems

• Discussions underway to get funding to implement specific adaptation solutions

• Full report(s) by late July 2011


Namaste / नमस्कार !


Thank you for your attention

For final report of TA 7417 contact (by August)

Bernd R Eggen

I’m available for future assignments, both in UK and abroad – www.eggen.co.uk

http://www.eggen.co.uk/

Documents

Presentation for BHS SWS / CIWEM - hydrology · Presentation for BHS SWS / CIWEM Climate Change and Hydrology: A Regional to Global Perspective – University of Exeter, Wednesday