Implications of climate change on existing and planned water resource development in the Upper Blue...

Implications of climate change on existing

and planned water resource development in

the Upper Blue Nile

AFRICA 2013 Conference: 16-18 April 2013

Matthew McCartney, Michael Girma and Solomon Demissie

• Simulate water demand for major production activities

(existing and planned)

• Evaluate the possible implications of CC on water resources/scheme performance (how do long-term benefits change?)

• Assess impacts of water resources development and CC on river flows

Objectives

Modeling

Climate change simulation (CCLM)

• temperature

• rainfall

• potential evapotranspiration

Hydrological modeling (SWAT)

• actual evapotranspiration

• groundwater recharge

• river flow

Water Resources Modeling (WEAP)

• irrigation

• hydropower

• river flow

Application of WEAP

• Water accounting model (mass balance) –

simulates water use across a range of

demands

• Data from:

– MoWR/EEPCo/NMA

– Basin Master Plans

– Irrigation efficiency studies

– New scheme feasibility studies

• Simulation 1983-2100 (monthly time step)

Development Scenarios

A1B scenario run with three development scenarios:

• Current Development (baseline)

• Intermediate Development: Planned development

(feasibility studies)

• Full Development: Potential development

(Basin Master Plans)

Schematic of development scenarios

Current

development

Intermediate

development

Full

Development

Existing and Planned schemes

Current

Development

Intermediate

Development

Full

Development

Irrigation (ha) 15,345 272,018 364,355

Hydropower (MW) 218 2,194 10,276

Storage (Bm3) 11.6 70.2 167

Hydrological Impacts

-60

-40

-20

0

20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18% c

han

ge in

an

nu

al f

low

Sub-Basin

A1B scenario: changes in flow

2021-2050 2071-2100

-40

-30

-20

-10

0

10

20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18% c

han

ge in

an

nu

al fl

ow

Sub-Basin

A1B scenario: changes in groundwater recharge

2021-2050 2071-2100

Climate Impacts (A1B scenario)

19

20

21

22

23

24

25

26

27

1980 2000 2020 2040 2060 2080 2100

Tem

per

atu

re (

oC

)

Basin: annual temperature (oC)

600

800

1000

1200

1400

1600

1800

2000

1980 2000 2020 2040 2060 2080 2100

Rai

nfa

ll (m

m)

Basin: annual rainfall

1200

1250

1300

1350

1400

1450

1500

1550

1600

1650

1980 2000 2020 2040 2060 2080 2100

Pote

ntia

l eva

potr

ansp

irat

ion

(mm

)

Basin: potential evapotranspiration

Impacts greatest in the

second half of the century

Climate impacts summary

Average annual

temperature (oC)

Average annual

rainfall (mm)

Potential Evapotranspiration

(mm)

1983-2102 20.9 1,310 1,363

2021-2050 21.9 1,290 1,405

2071-2100 24.9 1,110 1,535

Irrigation (1)

6,000

7,000

8,000

9,000

10,000

11,000

12,000

1980 2000 2020 2040 2060 2080 2100

Ave

rage

an

nu

al ir

riga

tio

n

Req

uir

men

t (

m3h

a-1)

Basin average irrigation requirement

1983-2012: 8,2442021-2050: 8,4912071-2100: 9,726

0

500

1,000

1,500

2,000

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecIrri

gati

on d

eman

d (m

3ha

-1)

Average monthly requirement

1983-2012 2021-2050 2071-2100

Irrigation (2)

1983-2012

2021-2050

2071-2100

0

500

1000

1500

2000

2500

3000

3500

Current

Development

Intermediate

Development

Full development

Mm

3

Irrigation water delivered Unmet demand

0

500

1000

1500

2000

2500

3000

3500

Current

Development

Intermediate

Development

Full development

Mm

3


0

500

1000

1500

2000

2500

3000

3500

Current

Development

Intermediate

Development

Full development

Mm

3


Hydropower (1)

0

10,000

20,000

30,000

40,000

50,000

60,000

19

83

19

89

19

95

20

01

20

07

20

13

20

19

20

25

20

31

20

37

20

43

20

49

20

55

20

61

20

67

20

73

20

79

20

85

20

91

20

97

Hyd

role

ctri

city

Gen

erat

ed (

GW

hy-1

)

Current development Intermediate Development Full Development

Hydropower (2)

Current Development Intermediate Development Full Development

Electricity

Generated

(GWhy-1)

% of

potential

Electricity

Generated

(GWhy-1)

% of

potential

Electricity

Generated

(GWhy-1)

% of

potential

1983-2012 1,397 100 12,814 98 40,803 91

2021-2050 1,390 100 12,962 99 44,245 98

2071-2100 1,138 82 8,422 64 28,449 63

Lake Tana: water levels

1,783

1,784

1,785

1,786

1,787

1980 2000 2020 2040 2060 2080 2100

Wat

er le

vel (

mas

l)Lake Tana: average annual water level


Flows

0200400600800

1,0001,2001,4001,600

1980 2000 2020 2040 2060 2080 2100

Flow

(m3s-1

)

Annual flow at Kessie


0

500

1,000

1,500

2,000

2,500

3,000

1980 2000 2020 2040 2060 2080 2100

Flow

(m3s-1

)Annual flow at the Ethiopia-Sudan border


Flow Summary (m3s-1)

Current Development Intermediate Development Full Development

Outflow

Tana

Kessie Border Outflow

Tana

Kessie Border Outflow

Tana

Kessie Border

1983-2012 177 617 1,655 81 522 1,622 87 528 1,599

2021-2050 158 659 1,713 61 563 1,678 63 564 1,683

2071-2100 45 444 1,327 10 409 1,305 21 421 1,301

Conclusions

• Combining climate, hydrological and water resources models provides a useful tool to assess the possible water resource implications of CC.

• Results indicate:

• long time horizon for full effect of climate change (“end of the century“)

• considerable spatial variability in hydrological impacts of CC

• clear trends but increasing variability in many hydrological variables

• Mid-range climate change is likely to impact the

performance of planned irrigation and hydropower schemes significantly by the end of the 21st century.

Thank you

Implications of climate change on existing and planned water resource development in the Upper Blue...

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