Rainfall and land use/cover analysis in four agricultural watersheds of Ethiopia

International Water Management Institute

Roundtable on Building Resilience to Climate Change through Community Dialogues

September 20, 2016, Addis Ababa

Overview of presentations

1. Introduction

2. Description of study areas

3. Rainfall analysis

4. Land use/cover changes

5. Implication/conclusion

1. IntroductionGenerally, agriculture in Ethiopia depends on rain-fed systems (10 M ha: 99.2%) which play and will continue to play a dominant role in providing food and livelihoods for an increasing population of the country.

Given that crop production is predominantly rain-fed, variability and unpredictability of rainfall has always been a major concern in the country.

Spatial and temporal variability including dry spells of rainfall have resulted in variation in rain-fed agricultural productivity and production.

Understanding trends in rainfall variability is important to develop resilient agro-ecosystems to support and transform livelihoods depending on rain-fed systems.

1. Introduction…1. Introduction…

The main objective of this report is to understand rainfall variability/trends and land use/cover changes in four watersheds of Ethiopia.

Expected results of the study are how:

i) change in rainfall characteristics enhance and/or undermine farmers efforts to transform livelihoods

ii) provide information and baseline for adaptation through AWM and-or landscape/land use changes

2. Study watershedWatersheds Region Basin Area (ha)

Alekit-Wonz (AW) Amhara Nile 470

Emba-hasti (EH) Tigray Awash 1,145

Borodo (BR) Oromia Awash 545

Jawe-gumbura (JG) SNNP Gibe 11,837

Water

sheds

Annual

rainfall (mm)

Kiremt season

rainfall (mm)

Belg season

Rainfall (mm)

AW 1478 (27) 1217 (29) 151 (45)

EH 749 (18) 454 (25) 162 (62)

BR 1096 (14) 736 (15) 252 (36)

JG 1185 (15) 616 (15) 379 (28)

3. Rainfall analysis: Annual rainfall trends

Kendall’s test shows significant decreasing trend of annual and kiremt rainfall

Kendall’s test shows significant decreasing trend of annual and belgrainfall - Decrease of belgmeans it is now so low that essentially cannot be cropped due to the high risk of too little rainfall

3. Rainfall analysis: Onset of kiremit rainfall • The average onset for

Borodo,Alekit-wonzand Jawe-gumburawas June 9/10 (Julian day=162/162).

• In Emba-hasti it seems to be very high variability of onset

• It will be particularly critical to get onset right here as the typical season is already short and with an long-term average sallow as 340 to 560 mm for long rainy season

y = -0.1949x + 551.97R² = 0.0237

150

160

170

180

190

200

1980 1985 1990 1995 2000 2005 2010 2015

On

set o

f kire

mit

rain

fall

(Ju

lian d

ays)

Borodo

Mean onset: 162

Standard deviation:

10.5 daysy = 0.1216x - 81.222

R² = 0.0123

150

155

160

165

170

175

180

1985 1990 1995 2000 2005 2010 2015

Alekit-wonz

Mean onset: 162

Standard deviation: 8

days

y = 0.0707x + 159.65R² = 0.0056

160

170

180

190

200

On

set o

f kire

mit r

ain

fall

(Ju

lian d

ays)

Jawe-

gumbura

Mean onset: 161

Standard deviation: 9 days

y = -0.1383x + 468.83R² = 0.0088

180

185

190

195

200

205

210Emba-hasti Mean onset: 192

Standard deviation: 16

3. Rainfall analysis: Dry spells (Emba-hasti watershed)

The average DS length in June, July, August and September were 25, 7.4, 4.5 and 12.5 days, respectively.

Distribution: Dry spells more than 10 days seriously affect and lower crop growth,

Trends: an increase of dry spells longer than 10 days fro June and September, increasing risk and making it difficult to enhance resilience in livelihood systems

Hence, it seems increasingly challenging to have predictive systems to help transform livelihoods,

4. Land use/cover changes

Photo: Zenebe Adimassu / IWMI

4. . Land use/cover change: Emba-hasti watershed

1986 2003 2006 2016

Source: IWMI

Land use /cover 1986 2003 2006 2016

Area

( ha)

% Area

( ha)

% Area

( ha)

% Area

( ha)

%

Roads 3.2 0.3 11.1 1.0 30.4 2.7 45.5 4.0

Bare land 206.8 18.1 281.8 24.6 248.2 21.7 158.2 13.8

Built up areas 0.1 0.0 0.3 0.0

Cultivated land 616.7 53.9 610.1 53.3 554.3 48.4 517.1 45.1

Forest land 126.1 11.0 123.3 10.8 166.9 14.6 250.6 21.9

Grazing land 5.2 0.5 14.5 1.3 20.9 1.8 24.6 2.1

Shrub/bush

land

186.8 16.3 104.1 9.1 125.5 11.0 150.0 13.1

4. Land use/cover change: Emba-hasti watershed

SWC structures on smallholder farms

Source: IWMI

Major SWC practices

Photos: Zenebe Adimassu / IWMI

-15

-10

-5

0

5

10

15

Bare land Cultivated land Forest land Grazing land Shrub/bush land

Ch

ange

in l

and

use

/co

ver

(%

)

Alekit-wonz Emba-hasti Borodo watershed Jawe-gumbura

Summary of land use/land cover changes (%) over 30 years (approx.) in four

watersheds in Ethiopia

4. Land use/cover change: summaryDespite rainfall trends , there has been 're greening' in terms of land use change into more permanent vegetated areas .

Landholdings have decreased and that rainfall trends shows more variable.

And so we can assume this is the pay off of SLM investments and farmers adaptive strategies

But we cannot say if these measures have managed to keep the crop-livelihood systems resilient : we don't know if the SWC measures have managed to maintain necessary yield levels despite the changes in rainfall.

5. Implications/Conclusion

The study shows there has been a trend of decreasing annual and belg (short) rainfall, and decrease in annual total wet days, and a decrease in heavy and very heavy rainfall Significant in Emba-hasti and Alekit-wonz.

Dry spells of more than 10 days were frequently observed in Alekit-wonz and Emba-hastiwatersheds affecting potential yields.

Rainfall trends slowly undermines farmers livelihood systems , and make them more vulnerable for shocks. To adapt and possibly transform , farmers need strategies to ensure livelihoods and income in new climatic realties

There is also continuous need to invest into soils and land to ensure the maximized benefit from rainfall to livelihood systems

5. Implications/Conclusion

In all watersheds, except Jawe-gumbura, there have been improvements in forest cover.

The positive change in forest land is at the expense of cultivated and grazing lands in most of the study areas: Management and ‘business’ plans are needed to sustain the positive change in forest cover.

There has been a tendency of decreasing forest land in the Jawe-gumbura watershed. This indicates that more effort and investment is required to maintain the existing forest land and afforestation of bare landscapes.

There s a need to provide baseline information on what the re-greening (increasing in forest/ tree cover) means for other ecosystems including healthy flows of water in landscapes and biodiversity

Thank you for your attention

For more information, please contact:

Zenebe Adimassu, IWMI E-mail: z.adimassu@cigar.org

Jennie Barron, IWMIE-mail: j.Barron@cigar.org

Photo: Zenebe Adimassu / IWMI

More information

Landsat 1986

Roads Bare

land

Built

up

areas

Cultivat

ed land

Forest

land

Grazi

ng

land

Shrub

/bush

land

Water

bodies

Geo

Eye

-1

20

16

Roads 96.55 0.00 0.00 0.45 0.00 0.96 0.00 0.00

Bare land 0.00 0.00 0.00 1.34 1.26 0.86 0.00 0.00

Built up areas 0.00 0.00 0.00 0.00 0.54 0.00 0.00 0.00

Cultivated

land

0.00 50.00 0.00 69.05 57.19 22.85 14.29 0.00

Forest land 0.00 50.00 0.00 17.52 27.52 5.45 57.14 0.00

Grazing land 3.45 0.00 0.00 8.65 10.25 68.93 0.00 0.00

Shrub/bush

land

0.00 0.00 0.00 2.99 3.24 0.96 28.57 0.00

Water bodies 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Land use/cover transition matrices (%) between 1986 2016 in Emba-hasti watershed

Land use/cover area and proportions in Alekit-wonz watershed over the years

Land use classes 1986 2001 2006 2014

Area

( ha)

% Area

( ha)

% Area

( ha)

% Area

( ha)

%

Roads 2.61 0.56 3.42 0.73 4.23 0.92 4.86 1.03

Bare land 0.72 0.15 0.9 0.19 16.65 3.64 5.76 1.23

Built up areas 0.09 0% 0.27 0

Cultivated land 321.66 68.5 326.7 69.5 286.02 62.4 272.7 58.0

Forest land 50.04 10.7 43.65 9.3 43.29 9.5 75.96 16.2

Grazing land 94.14 20.0 86.58 18.4 89.46 19.5 97.92 20.8

Shrub/bush land 0.63 0.1 8.55 1.8 6.84 1.5 12.33 2.6

Water bodies 0.09 0.0 * 0.0

Clouds and

Shadows

0 0 0 0 24.30 5.3 0 1.03

Total 469.8 469.8 471.0 470.0

Land use/cover area and proportions in Borodo watershed over the years

Land use classes 1986 2000 2006 2015

Area

( ha)

% Area

( ha)

% Area

( ha)

% Area

( ha)

%

Roads 5.76 1.06 13.68 2.55 14.49 2.66 18.36 3.48

Bare land 5.40 0.99 7.92 1.48 27.99 5.14 63.54 12.06

Built up areas 0.45 0.08 0.27 0.05

Cultivated land 306.63 56.26 332.91 62.15 281.07 51.65 267.39 50.75

Forest land 154.08 28.27 158.76 29.64 149.13 27.40 157.95 29.98

Grazing land 0.00 0.00 0.18 0.03 16.47 3.03 0.18 0.03

Shrub/bush land 72.90 13.38 31.32 5.85 54.63 10.04 37.08 7.04

Water bodies 0.00 0.00 *** ***

Total 544.77 544.77 544.23 544.77

Land use classes 1986 2001 2015

Area ( ha) % Area ha) % Area( ha) %

Roads 51.21 0.43 100.89 0.86 393.57 3.37

Bare land 1597.14 13.49 1196.37 10.18 800.55 6.85

Built up areas 130.68 1.10 149.58 1.27 256.32 2.19

Cultivated land 5570.64 47.06 6348.69 54.01 6290.10 53.84

Forest land 2127.78 17.98 2561.13 21.79 2102.13 17.99

Grazing land 1569.51 13.26 953.46 8.11 1057.59 9.05

Shrub/bush land 783.54 6.62 437.49 3.72 771.21 6.60

Water bodies 6.12 0.05 7.47 0.06 10.80 0.09

Total 11836.62 11755.08 11682.27

Land use/cover area and proportions in Jawe-gumbura watershed over the years