1. Hammamet, Tunisia, 25-26 September 2014
National Workshop on Water Resources and Livelihoods in the Dry Areas Considering Climate Uncertainty
Hammamet, Tunisia, September 2014
INTEGRATED TECHNICAL AND ECONOMIC ASSESSMENT OF WATER HARVESTING INTERVENTIONS IN PERSPECTIVE FOR CC MITIGATION (Case of Oum Zessar Watershed)

2. OUTLINE

3. Introduction & general approach
Review of conducted works
WLI and CRP-DS findings
Conclusions & prospects

4. INTRODUCTION

5. Socio-economic mutations
Climate
Soil
Rainfed dominated
Socio-economic mutations CC

6. WH
Biophysical
Environmental
Economic
Social CC

7. OVERVIEW OF CONDUCTED WORKS

8. Catchment
Cropping Area
400
100
Jessour
Dike

9. Mean annual temperature (°C) 20
Oum Zessar
Area (km2)
350
Annual rainfall (mm)
180
Mean annual temperature (°C) 20
Altitude (m)
0-715
Population (inhabitants)
24000

11. Water balance Hyd. Year ETrel (2/1) ETrel (3/1) ETrel (3/2) Wet 1.1 -
Water balance on the terrace
Hyd. Year
ETrel (2/1)
ETrel (3/1)
ETrel (3/2)
Wet
1.1 -
Dry
2.3
2.5
Very dry
12.0
15.6
1.3
Hyd. Year: type of the hydrological year
ETrel: relative ETa
1: ETa with only rainfall on the terrace
2: ETa with rainfall and runoff on the terrace
3: ETa with rainfall, runoff and supplemental irrigation

12. Recharge structures Capacity loss of the gabion structures Wadi
Location
Sediment (cm)
Loss (%)
Oum Zessar
Down 5
Koutine 50 14
Mid 20 18 21
Nkim 56
Hallouf Up
150 88

13. Recharge well filter transmission capacity
Runs
K (cm/h)
Loss (%) 1
193.5
0.0 5
52.7
72.8 6
40.2
79.2 7
33.0
82.9 13
7.0
96.4

14. Effets des aménagements
Piézométrie et exploitation de la nappe de ZK
Effets des aménagements
Exploitation accrue !!!
Chute de la de la PZ quelque soit la pluviométrie

15. SC0
SC1
SC2
SC3 mm %
Rainfall
183.9  - - ET
107.0a
58.2
147.2b
80.1
150.9 b
82.0
Outflow
34.3 a
18.7
4.0 b
2.2
0.1 c
0.0
Perco
14.5 a
7.9
24.3 b
13.2
28.2 b
15.4
28.3 b
TLOSS
28.0 a
15.2
8.2 b
4.4
3.1 c
1.7
3.2 c
Seepage
0 a
1.1 b
0.6
0.9 b
0.5

16. SC0
SC2 VD D N W VW VD

17. WLI CRP-DS FINDINGS

18. Chabeat Anez Site

19. Loudayette site

20. Oued Moussa Site

21. Integrated impact assessment of livelihood & water management practices in oum zessar watershed

22. Methodology
Extended cost-benefit analysis (ECBA) to environmental externalities : It was carried out in order to assess the costs and benefits of WHT works implemented by the WLI project in the selected farms. External economic and environmental phenomena, tangible as well as intangible effects have been integrated in the analysis. Evaluation criteria used were the Net Present Value (NPV) and the Internal Rate of Return (IRR). Data for CBA come from a survey conducted during An appropriate time horizon was set at 30 years
Sustainable Livelihoods Approach (SLA): this approach is carried out in order to assess patterns and drivers impacts on livelihood condition. SLA is an analytical framework that helps to understand the factors that influence the ability of people to achieve sustainable development in a particular circumstance. The livelihood framework is based on five capital assets; social, human, physical and financial capital. To evaluate the five livelihood assets in the up-stream, mid-stream and down-stream of Oum Zessar watershed, data has been gathered using socio economic survey (139 surveys) conducted in LADA approach was adapted in order to select indicators and carry out the scoring for each asset.

23. List of indicators by type of livelihood capital
Sustainable Livelihoods Approach (SLA)
List of indicators by type of livelihood capital
Natural capital
Financial capital
Physical capital
Human capital
Social capital
Livestock
Farm size
Land quality
Water quality
Olive trees
Agriculture income
Livestock income
Off-farm income
Jessour
Ownership of plowing means
Education,
Household size
Age
Households expenditure
Member of association, Distance to nearest hospital , Certificate of Ownership, SONEDE network

24. Social capital is the most dominating capital in the three locations followed by physical capital mainly in Beni khdeche and Sidi Makhlouf.
Financial capital seems to be not representative in the different location due to the low agriculture and livestock incomes. Projections indicate that the livelihood assets will be changed during period.
Physical, human and social capital will be improved with very little increment in financial capital.
Natural capital will slowly decrease. Factors that contributed to the decline of natural capital were agricultural intensification and poor land management.

25. Trends of different livelihood capitals over time

26. IRR and sensitivity analysis (WHT investment at farm level)
IRR %
Observed
Costs + 10 %
Benefits - 20 %
Financial CBA
24%
27%
21%
Economic CBA
29%
23%
Extended CBA
20%
Net Present Value , WHT investment
NPV (DT)
Discount rate 
12%
10% 8%
Costs + 10 %
Benefits - 20 %
Finacial CBA
2491
3615
5231
2340
1691
Economic CBA
3023
4283
6092
2884
2140
Extended CBA
2073
3027
4402
1910
1333

27. The CBA shows that the WHT works are profitable at the private level with an IRR of 24 % and an NPV (at 12 % discount rate) of 2491 DT.
The inclusion in the analysis of the off-site benefits improves the economic profitability considerably, with an NPV (at 12% discount rate) of 3023 DT DT and an IRR of 27 %.
The incorporation of other external and indirect effects with no market prices (failure of jessour) resulted in a decrease NPV (at 12 % discount rate) of 2073 DT and IRR of 23 %.
The sensitivity analysis confirm the basic analysis.
The WHT works are apparently beneficial at private and social levels for local population within the watershed.
Conclusion
Integrated impact assessment can be a useful tool for community inclusion and livelihood strategy assessment. Sustainable land and water management practices and livelihood strategies improve rural livelihoods of farmers in dry area. The presented results are under finalization, the next steps consist of hypothesis verification and scenario building.

28. CONCLUSIONS & PROSPECTS

29. Water harvesting techniques have been developed since antiquity to cope with climate variability in the dry areas.
They played major role in the development of rainfed agriculture and others (recharge, flood control, etc.)
With the prospect of CC, those systems/techniques would be more useful.

30. Technical adaptation and adoption (SI, etc.)
However:
Economic profitability is becoming increasingly low and variable
Migration (due to cities attractions) and competition of other sectors would favor abandonment
Need for new paradigm (water productivity, local products value chain, etc.)
Technical adaptation and adoption (SI, etc.)
Other functions (ecosystem services, etc.)

31. Thank you