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Draft
Project: Second National Communication on Climate Change (SNC)
Water Resources Vulnerability and Adaptation
to Climate Change in Yemen Republic:
The Case Study of Wadi Surdud with its Contributing Catchments
Prepared by
Saif Alhakimi1, Team Leader
Abdulla Noaman2
Mansour Haidera3
Submitted to
Environment Protection Authority (EPA), Yemen
1
Assistant Professor, Faculty of Science, Sana'a University, Sana'a, Yemen
Associate Professor, Faculty of Engineering, Sana'a University, Sana'a, Yemen
3 Assistant professor, Faculty of Engineering, Sana'a Univer sity, Sana'a, Yemen
2
1
Contents
List of Abbreviations ........................................................................................... iii
List of Figures ...................................................................................................... vi
Summary ............................................................................................................... 1
1. Introduction....................................................................................................... 2
2. Objectives of this study .................................................................................... 4
3. Methodology and tools ..................................................................................... 4
4. General characteristics of the study area ....................................................... 5
4.1 Location............................................................................................................................ 5
4.2 Topography, Geology, and Land Use ............................................................................... 5
4.3 Geology and Stratigraphy .............................................................................................. 6
5. Hydro-meteorological conditions ................................................................... 8
5.1 Rainfall ............................................................................................................................. 8
5.2 Temperature .................................................................................................................. 10
5.3 Relative Humidity ......................................................................................................... 11
5.4 Sunshine duration ......................................................................................................... 11
5.5 Wind speed..................................................................................................................... 12
5.6 Potential evaportranspiration ...................................................................................... 13
6. Surface water (Runoff) ................................................................................... 13
7. Groundwater ................................................................................................... 15
8. Population ........................................................................................................ 16
9. Methodology .................................................................................................... 18
9.1 WEAP Model development .......................................................................................... 18
Catchment Area ............................................................................................................................................ 21
Deep Conductivity ........................................................................................................................................ 22
Initial Z2 ....................................................................................................................................................... 22
Soil Water (Root Zone) Capacity ................................................................................................................. 22
Root Zone Conductivity ................................................................................................................................ 22
Preferred Flow Direction ............................................................................................................................. 22
Initial Z1 ....................................................................................................................................................... 23
Crop Coefficient Kc ...................................................................................................................................... 23
Leaf Area Index ............................................................................................................................................ 23
Precipitation ................................................................................................................................................. 23
Temperature, Wind and Humidity ................................................................................................................ 23
10. Climate input base line parameters ............................................................ 24
11. Model calibration and results ...................................................................... 25
12. Strategies development and results ............................................................. 28
13. Adaptation strategies prioritization based on stakeholder criteria
weighting ....................................................................................................... 32
13.1 Discussion of results: .................................................................................................... 33
14. Policy and Institutional Issues.....................................................................35
14.1 Institutional set up…………………………………………………………………….35
14. 2 Strategic, legislative and policy issues……………………………………………….38
14.3 Constraints and gaps for vulnerability assessments……………………………… ..41
ii
14.4 List of projects or programs proposed for financing…………………………………42
15. Conclusion and recommendations .............................................................. 46
Acknowledgment ......................................................................................... 49
References..................................................................................................... 50
Annex A ........................................................................................................ 51
Annex B ........................................................................................................ 57
iii
List of Abbreviations
AGC
APF
CCU
CDM
EPA
GDP
GEF
NCCC
MDGs
MPIC
MWE
NAPA
NCAP
NGOs
NWRA
NWSA
TOR
UN
UNDP
UNEP
UNFCCC
V&A
WB
WEAP
WEC
Arab Gulf Council
Adaptation Policy Framework
Climate Change Unit
Clean Development Mechanism
Environmental Protection Agency-Yemen
General Domestic Product
Global Environment Facility
National Climate Change Committee
Millennium Development Goals
Ministry of Planning and International
Cooperation
Ministry of Water and Environment
National Adaptation Plan of Action
Netherlands Climate Assistance Program
Non-governmental Organizations
National Water Resource Authority
National Water and Sanitation Authority
Terms of References
United Nations
United Nations Development Program
United Nation Environmental Program
United Nations Framework Convention on
Climate Change
Vulnerability and Adaptation
World Bank
Water Evaluation and Planning software
Water and Environment Center
iii
List of Figures
Figure 7. Mean monthly wind speed in Wadi Surdud plain and surrounding areas……………………….13
Figure 8. Average Monthly Flow Volumes at Fag Alhussein Station (after NWRA, 2008)………………15
Figure 9. Wadi Surdud Area Population Distribution 2007………………………………………………..17
Figure 10. Distribution of bore holes in Wadi Surdud Plain……………………………………………….17
Figure 11. Schematic diagram of WEAP model for Wadi Surdud…………………………………………19
Figure 12. Soil moisture method Model (Source: Sieber, 2005)…………………………………………...20
Figure 13. Average annual rainfall of all stations in Upper Cachment (mountainous region)……………..24
Figure 14. Groundwater storage in the Quaternary aquifer under climate scenarios…………………....... 27
Figure 15. Groundwater storage in the Mesozoic and Shallow aquifers under climate scenarios……….....27
Figure 16. Strategies effect on all aquifers storage during the Reference Scenario………………………...29
Figure 17. Strategies effect on the Quaternary aquifer storage during the UKHI Scenario………………...29
Figure 18. Strategies effect on Mesozoic and Shallow aquifers' storage during the UKHI Scenario……....30
Figure 19. Coastal catchments inflows and outflows……………………………………………………….31
Figure 20. Mountainous catchments inflows and outflows…………………………………………………31
List of Tables
Table 1. lists of the weather monitoring stations including the average monthly rainfall (TDA, 2008)…….9
Table 2. Input Parameters and Sensitivity………………………………………………………………….21
Table 3. Comparison between the reported and the predicted Wadi Surdud'……………………… ……26
Table 4. Summary results of scenarios analysis and stakeholders meetings-Wadi Surdud………… …… 36
Table 5. Example of institutional and legal measures……………………………………………………..44
Table 6. Example of measures for identification, assessment and mitigation of negative climate
change impacts……………………………………………………………………………………45
iv
Executive Summary
The main purpose of this study is to assess climate change impacts (gains and losses) on water
resources and water management in Wadi Surdud drainage basin area, under certain climate change
scenarios, and to identify the required and adequate measures and adaptation strategies that can be
followed or applied in such area. The study area, Wadi Surdud drainage basin, forms one part of the
western drainage basins area of Yemen. It occupies a surface area of nearly 4050 km2, and is
featured by an arid/semi-arid climate. Wadi Surdud is considered one of the main wadis
(intermittent streams) descending from, and draining waters from, the semi-arid western mountain
slopes of Yemen, into the Red Sea basin. The upper cachment area of the drainage basin has a rough
and dissected topography, with an elevation reaching up to 3700 m (a.s.l). In an area approaching
the Red Sea region, Wadi Surdud debouches into rather flat area (Tihama Zone). The average
rainfall in the drainage basin is reported to be between 300 mm and 600 mm, for the upper and
middle catchment areas, but significantly less in the Tihama part (around 100 mm). The study area is
of a special interest due to its social and economical importance, both because it includes major
agricultural activities which support not only Alhudaida city but also Sana’a city and some other
governorates with varieties of crops. As a result, the water resources in the area generally suffer
from an escalating pressure due to the high consumption of water by agriculture to cope with the
increasing demand by population growth in cities. Therefore, reduction of rainfall, as a result of
climate change, will make the situation even worst. In this study, a Water Evaluation and Planning
System (WEAP) model was used to evaluate water demands, supplies and scarcity among all water
users sectors under a range of potential climate change scenarios and adaptation strategies. The
simulation period in this study was twenty five years (2008-2033) and the adapted strategies and
measures were, Rehabilitation of traditional irrigation channels, Conveying irrigation water
through closed conduits, and the use of drip irrigation method and changing crop pattern. The
simulation results showed that improving irrigation efficiency through using drip irrigation
technique is found to be the best strategy to be adopted, followed by the strategy of using closed
conduits for conveying irrigation water to farms, and then the least preferred strategy, the
rehabilitation of traditional irrigation channels while changing crop pattern, which was found to
have little impact on water savings for our case. The amount of water saved for the adapted
strategies, drip irrigation and closed conduits, are 157.3 MCM/y and 91 MCM/y, respectively.
1
1. Introduction
Yemen, which is currently a home to 23 million people, has limited resources notably scarce water,
a shortage of arable land and declining oil reserves. Its population is young, predominantly rural (73
percent) and rapidly growing (World Bank, 2009). The long term average amount of water available
is less than 200m3 per capita per year (van der Gun, 2009) and predicted to decline to below 150m3
per capita per year (EPA, 2009). The National Water Resources Agency (NWRA) state that the
sustainable use of water is 2100 to 2500Mm3 and that current use is about 3400Mm3; thus the
country suffers from an acute water shortage. Although agriculture contributes a small amount to
Gross Domestic Product (GDP) it provides employment and family income for more than half the
country’s labour force and consumes 95 percent of available water resources.
The Economist further revealed that Yemen ranks 6 among the nations of lowest quality of life
index (38.5 against 100 in New York); and ranks 10 among the lowest purchasing power parity (2.2
against 100 in USA). Moreover, the country stands 26th position with a very high consumer price
index of 10.8% in the year 2005. Its environmental sustainability index is one of the lowest in the
World.
According to the Statistical Year Book 2008 of CSO, Ministry of Planning and International
Cooperation, ROY, the gross domestic product (GDP) at market prices of 2008 for Yemen was
estimated at 2551994 MYR (13811 Million USD) and gross national product (GNP) at market
prices of 2008 was 2337781 MYR (12652 Million USD). The per capita GNP thus comes to
120194 YR (659 USD) for the year 2008. It is a matter of satisfaction that the per capita GNP is
showing a steady increasing trend .
The major sectors that play important roles in the country's economy are agriculture, mining,
manufacturing, trade, transport and storage, financial and other services. The share of these sectors
in GDP for 2008 was 20.06, 14.24, 9.44, 8.99, 13.25, 8.87 and 20.00 percent, respectively.
According to the Agricultural Statistics Year Book 2008, published by the Ministry of Agriculture &
Irrigation, ROY, the agriculture sector is not only the largest contributor to the national economy of
Yemen, but also it employs the majority (around 60%) of the active labour force of the country. Out
2
of the total area of 1.66 million ha, 65% area is cultivated and the remaining 35% uncultivated. The
total number of agricultural holdings in Yemen in 2004 was 1.18 million and the total cultivated
area was nearly 1.19 million ha. In other words, the average size of holding was around 1 ha.
Among the group of crops, cereals occupy about 58%, vegetables 6%, fruits 6.8%, legumes 2.7%,
cash crops 16.3% and fodders 10.2% of the total crop area of 1.19 million ha. Sorghum accounting
for 62.5% of the total area under cereals is single major cereal crop followed by millet 14.5%, wheat
12.3%, maize 5.6% and barley 5.1% of the total cereals grown in the country.
It is further revealed by the Agricultural Statistics Year Book 2004 that of the total cultivated area in
the country 45% is rainfed, 37% is well irrigated, 5% is irrigated through spring water, and the
remaining 13% is irrigated by flood or spate irrigation. In other words, groundwater resource is the
major source of irrigation in the country The study area (Figure 1) is part of the western drainage
basin of Yemen. Wadi Surdud, is located between 14° 58′–15° 35′ N and 43° 20′–43° 58′ E on the
so-called Western Escarpment of the highlands along western part of the Yemen Republic (NWRA,
2008). Wadi Surdud is one of seven major wadis, which developed in these highlands (Upper and
Middle Catchments) and flow westwards to the Red Sea across the semi-arid coastal plain locally
known as Tihama (Lower catchment), which is about 50 km far from the sea (Figure 2). The total
cachment area of Wadi Surdud, including the plain, is 2750 km2. The average rainfall is between
300mm and 600mm in the upper and middle cachment areas but significantly less in the Tihama part
(around 100mm). The annual average temperatures in the upper catchment and lower cachment
respectively are 18 and 300C and for the relative humidity are 58 and 65% (Adna, 2002, NWRA,
2008, Van der Gun, 1986). According to Water Resources Assessment Yemen project (WRAY) and
Van der Gun, and Aziz (1995) potential evapotranspiration at mountainous area is 2014mm/year and
at the coastal area is 2291mm/year.
Selection of the study area was largely based on the widespread area coverage; different
geographical and climatic regions, the Highlands, the Midlands (plateau and escarpment) and the
Low Lands (coastal plain zone) in addition to the level of socio-economic livelihood where the GDP
per capita is US$500/year and reasonably different environmental status. The study area has special
social and economical importance both because it includes major agricultural activities which
3
support not only City but even cites beyond Al-Hudaida City borders with verity of crops. As a
result, the water resources in the area generally suffer from escalating pressures due to the high
consumption of water by agriculture to cope with increase demand raised by population increase in
related cities. Reduction of rainfall, as a result of climate change, made the situation even worse
with emerging of numerous water use conflicts due to competitions between different water use
sectors. Several groundwater studies indicated an already significant drop in the aquifers water level,
which will eventually lead to depletion and rising water cost.
2. Objective of this study
The main objective of this study is to:
a. assess the vulnerability and adaptation of water resources in Surdod Drainage Basin area,
under current and future climate conditions, and consequently
b. assess future climate risks and adaptation measures with an attempt of developing an
adaptation policy framework, that can be accounted for in national development
planning.
3. Methodology and tools
The assessments conducted for the study area are accomplished through the following:

Collection of all available and relevant data on water resources and availability, land use and
demand, water use sectors and demand, meteorological data and socio-economic aspects,
from reports, maps and other sources.

Rapid rural appraisal method was used for participatory assessments among stakeholders
and decision makers to discuss their concerns regarding issues of water scarcity and possible
adaptation measures.

Identification of key policy issues, to assist in scoping the scale of risks associated with
projected climate change, aid in the identification of priorities for adaptation and support the
development of a national adaptation strategy.

Identification of the expected outputs of the study and linking them to national development
planning priorities.
4

The use of WEAP and MCA-WEAP modeling software and tools, developed by Stockholm
Environment Institute-USA, for determining water balance conditions and evaluating water
needs and scarcity among all water using sectors, under two potential climate change
scenarios (dry and wet conditions), and various adaptation measures.
4. General characteristics of study area
4.1 Location
Wadi Surdud (2370 km2), is located between latitudes 14° 58′ and 15° 35′ N and longitudes
43° 20′ and 43° 58′ E, on the so-called the Western Escarpment of Yemen Highlands, along
the western part of Yemen Republic (Figure 1). It is one of seven major wadis, which
developed in such highlands, flowing westwards into the Red Sea, and crossing the semi-arid
coastal plain, locally known as Tihama.
.
4.2 Topography, Geology, and Land Use
The area consists of two very distinct geographical zones; the topographical low 'coastal
plain zone' in the west that forms part of the Tihama plain and the mountainous 'catchment
area' to the east. The western part is composed of a gently sloping zone at low elevation,
excluding the Qumah mountain with an elevation of 78 m a.s.l., otherwise all the eastern part
catchment area is rugged, strongly dissected by Wadi Surdod's stream network, within the
mountainous zone that reaches elevations over 3000 m above sea level. The highest elevation
in the eastern boundary is 3666 m a.s.l. (Jabal An Nabi Shuayb), the highest mountain in the
Arabian Peninsula (Figure 2). The total catchment area of Wadi Surdud basin, including its
plain, is 2750 km2.
5
Figure 1: Location of Wadi Surdud and its contributing catchments in Yemen
4.3 Geology and Stratigraphy
The geologic setting of the present Tihama Plain (Figure 2) is completely controlled by the
Red Sea Graben, which was formed during the Tertiary period, initiated by fracturing, step
faulting and rifting along an anticlinal structure of the African-Arabian shield. The
structural and stratigraphic construction of the area is controlled by the tectonic and
environment history of the Red Sea Rift System. The Red Sea rift valley is an elongate
NNW-SSE basin between the African Continent and the Arabian Peninsula, on both sides
separated by faults from the prominent escarpments of the uplifted margins of the
Precambrian shields. The main stratigraphic units are Precambrian Basement (PC),
Paleozoic and Mesozoic sedimentary rocks (P/M), Cainozoic Tertiary Formation (C) and
Quaternary Sediments (Q):
6
Figure 2: Geological map of the Surdud catchment area (SAWAS, 1996)
There are three aquifers in the study area, the Mesozoic aquifer in the mountainous area, the
Shallow aquifer along Wadi Surdud reaches and the Quaternary aquifer in the costal area.
The shallow aquifer is recharged by wadi bed infiltration from wadi flood and baseflow as
interflow from Mesozoic aquifer. In the mountainous area there are six sub-catchments
drain to six wadi tributaries which constitute the Wadi Surdud headflow are reflected in
Weap Model. In the coastal area there are thirteen agriculture lands or sub-catchments (see
Figure 3). For each sub-cachment and based on Van der Gun and Wesseling (1991) and
field investigations data on area, land use, crop pattern, crop coefficient values, kc, (FAO,
1989) and crop production costs are modeled. It was assumed that there is 1.5% annual
increase in agriculture area. Regarding municipal water, it is represented by two demand
nodes, one in the mountainous region and the other in the coastal region.
7
5. Hydro-meteorological conditions
5.1 Rainfall
Two rainy seasons can be distinguished in the study area: one in spring, and the other in
summer, with 45% of rainfall occurring during July and August. Annual precipitation ranges
from 400 mm in the mountain to 50 mm at the outlet of the study area in the sea. The number
of rainy days (>10 mm) is around 17 which is typical of desert climate. The rainy events are
characterized by a rapid onset and high intensity short duration. Shower storms are
infrequent, localized, and variable within the basin. Potential evaportransporation [ETo]
exceeds the monthly and annual rainfall amounts observed. Calculated [ETo] according to
the Penman method is around 1825 mm/year.
Rainfall in the mountainous and steep Upper Wadi Surdud catchment is quickly followed by
runoff peaks in the wadis, like elsewhere in Yemen. The rising limbs of the flood
hydrographs usually last only some 10 to 30 minutes. The recession -although slower- is
quick as well, and direct runoff is disappearing completely within one or two days after the
flood peaks.
Hydrological monitoring was considered by TDA the most essential input to a better
hydrological assessment of Wadi Surdud. Consequently, a hydrological network was
designed, installed and operated. Determination of the type and the locations of the
monitoring stations was guided by the objectives of the hydrological study and on ideas on
the hydrological processes and features in the area. Table 1 and Figure3 lists the monitoring
stations including the average monthly rainfall.
8
Table 1: lists of weather monitoring stations including average monthly rainfall (TDA, 2008)
Average rainfall (mm)
Meteorological stations
Mayan Assalf Mafhak Rujum Qadam Khamis Ghamr Zuhaif Khamlu Dhahi
Data range
1984-2007
Month
1984-1997
January
3.6
4.2
1.9
3.4
0.50
3.1
3.3
5.7
2.5
0.8
February
5.8
7.3
6.8
4.6
4.00
5.8
7.7
8.2
4.6
5.0
March
18.9
29.5
22.0
17.1
18.56
7.0
29.7
13.7
6.3
1.7
April
44.7
87.1
44.7
61.5
63.58
44.0
74.2
61.7
36.9
12.6
May
23.2
31.4
23.7
33.5
57.01
38.9
67.4
52.5
40.1
13.8
June
8.6
10.4
7.3
30.4
14.04
25.8
26.1
18.7
17.2
0.7
July
43.5
77.9
37.8
59.8
45.96
54.7
33.7
34.2
28.4
7.1
August
44.5
95.4
55.4
124.8
84.36
72.8
70.1
76.3
74.5
39.2
September
2.7
15.4
10.0
41.4
24.61
34.7
28.5
46.8
35.4
34.5
October
2.6
9.1
7.2
8.9
22.16
6.0
12.2
22.1
12.7
17.1
November
4.0
12.3
4.5
6.1
9.87
4.6
11.2
12.8
4.6
1.3
14.1
11.0
4.9
6.2
2.61
4.5
7.3
7.5
5.3
216.2
391
226.2
397.7
347.26
301.9
371.4
360.2
268.5
December
Total
450
mm
400
350
300
250
200
150
100
50
A
ss
al
f
M
af
ha
q
M
ay
an
G
ha
m
r
Zu
ha
if
R
uj
um
K
ha
m
lu
K
ha
m
is
Q
ad
am
D
ah
i
Za
yd
iy
ah
0
Figure 3. Mean annual rainfall in Wadi Surdud catchment area (after NWRA, 2008).
9
3.9
137.7
5.2 Temperature
The annual range of temperature variation in the Wadi Surdud coastal plain of the warmest and
coolest month of the year is about eight ◦C as recorded in Dahi meteorological station. Fig 4
shows that there is no big difference to west of the area to sea direction (in Hudaydah
meteorological station near coast) due to a slightly solar radiation variation over the territory and
to other associated factors, based on data for a period 1984-1991, see appendix IV. The lowest
temperature records in Dahi monitoring station is 25 ◦C as average in January and the highest is
a little more than 34 ◦C in June month. The highest temperature is always predominantly during
summer season (June-September), with a highest average rains in August and September
months in Dahi and surrounding areas. The temperature in the mountainous areas to the east
(Catchment Area) become lower and lower by increasing elevation.
40
◦c35
30
25
20
15
10
5
DAHI
Hudaydah
Zuhrah
0
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Figure 4. Mean monthly temperature in Wadi Surdud plain and surrounding areas (after
NWRA, 2008).
10
5.3 Relative Humidity
Mean monthly relative air humidity in Wadi Surdud coastal plain (middle of the projected area)
is recorded between 43 to 65 % depending on temperature and rainy seasons. It reaches lowest
values about 43 % in July with highest monthly average temperature 34 ◦C and increases to
about 50 % in August then to about 53 % in September with about 40 and 35 mm of rains
respectively. Fig 5 shows monthly average relative humidity for three meteorological stations in
the middle of the study area and to the north and the southwest direction of the area.
90
%
80
70
60
50
40
30
20
10
DAHI
Hudaydah
Zuhrah
0
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Figure 5. Mean monthly relative humidity in Wadi Surdud plain and surrounding
areas (after NWRA, 2008).
5.4 Sunshine duration
Clear skies are predominant in the region during most of the year. Recorded annual mean values
are between 5 and 8.5 hours/day in the middle of the projected area, which corresponds from 43
and 71 % of the theoretical maximum respectively in Dahi and between 4.7 and 8.7 % in Zuhara
meteorological station to the north. Figure (6) shows daily sunshine hours excluding the
minimum records during summer rainy season (July-September).
11
hours/day
10.0
9.0
8.0
7.0
6.0
5.0
4.0
3.0
2.0
1.0
0.0
DAHI
Zuhrah
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Figure 6: Mean monthly sunshine duration in Wadi Surdud plain and
surrounding areas (after NWRA, 2008).
5.5 Wind speed
The available reflected records of wind speed in the area shows that in the middle of study area
in Dahi meteorological station is low, monthly average wind speed between 0.9 to 1.0 m/s
approximately all year excluding July and August when it reaches to 1.3 and 1.2 m/s
respectively. Wind speed increasing to the west of the area and it reaches to 5.3 m/s near the red
sea, as it is obtained in Hudaydah meteorological station. Figure 7 shows monthly average wind
speed in three meteorological stations.
12
6.0
m/s
5.0
4.0
3.0
2.0
1.0
DAHI
Hudaydah
Zuhrah
0.0
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Figure 7: Mean monthly wind speed in Wadi Surdud plain and surrounding areas (after NWRA,
2008).
5.6 Potential evaportranspiration
Potential evapotranspiration (ETp) far exceeds the observed monthly and annual rainfall
amounts at Ad Dahi in the middle of the area. Potential evapotranspiration (ETp) calculated
according to the Penman method around 2082 mm/year, while the average annual precipitation
around 138 mm/year according to (Jac van der Gun and Abdul Aziz Ahmed, 1995). Reference
evaporation E0 is about 10 % higher than corresponding potential evapotranspiration ETp,
values depending on specific conditions. The ratio between average annual precipitation (P) and
annual reference evaporation (E0), 0.03<P/E0<0.25 shows that the area is classified as arid area.
6. Surface water (Runoff)
During rainy seasons drops of rain run of down-slope of Wadi Surdud catchment area as all
western slopes as overland flow to the nearest branch of drainage network to contain a quick
(direct) flow. The volume of surface water produced by the catchment is important to be
identified for potential water resources utilization. The first flow measures has been made by
Russians for 1965-1967 then GDH's WRAY project rehabilitated the stream gauging station of
Fug Alhussein installed by Hallecrow and by installing new bubble gauge recorder since the
13
beginning of 1984. The location site of the station near the boundary between mountainous
catchment area (around 2370 Km2) and coastal plain area where runoff volumes are highest and
wadi river passes through a narrow gorge. Since that, daily-recorded data is fully available for
1984-1985 and partially for 1986-1989 before the station has been stopped and damaged.
By analyzing available data and published data, some statistics can be derived: The Wadi Surdud
generally characterized by abruptly rising peaks that rapidly recede during spring and summer
rainy seasons (Instantaneous floods). In between these peaks, the wadi has a permanent base-flow
of 0.5-1.0 m3/s as observed during last years, 90 % of it yields by Khamis Bani Sa'ad branch. The
baseflow contributes around 40 % of the annual flow volumes (Jac van der Gun and Wesseling,
1990). The volume of annual runoff is between 50 and 100 Mm3, gauged calculated average for
periods 1965-1969 and 1984-1989 is 69.3 Mm3 (Figure 8). A double peaked floods event is
common, the observed maximum flood peak 600 m3/s was recorded in May 1984 (Jac van der
Gun, 1985) and there was no records after 1991. Year to year variation of stream flow is high.
The monthly distribution of flows (Figure 4) gives an impression of the regimes of the wadi.
Generally, there are two flood seasons, corresponding with the rainy seasons mentioned in
paragraph above. The records also show that the summer season bring s slightly more water than
the spring season.
Due to data variable reliability and accuracy, Jac vander Gun and Abdul Aziz Ahmed, 1995
estimated mean annual runoff volumes for runoff producing catchments in Yemen by using a
uniform depth of rain water over the entire catchment area (mean 29.2 mm/year for Wadi Surdud
catchment area) this was by estimating average annual rainfall about 440 mm/year and Runoff
Coefficient (RC) for Wadi Surdud as 0.066 and scaling down the runoff volumes to uniform
catchment size and rainfall rate (m3 of runoff per m2). The result was 65 Mm3/year, which is
about equal to gauged volume.
14
6
Mean Monthly Flows at Faj Al Hussein
(Records 1965-1967,1984-1989)
5
Mm3
4
3
2
1
0
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Figure 8: Average Monthly Flow Volumes at Fag Alhussein Station (after NWRA, 2008)
7. Groundwater
Groundwater in Wadi Surdud is present virtually everywhere, but a condition of groundwater
exploitation it varies widely from zone to another. The principal aquifer system in Wadi Surdud is
formed by the Quaternary deposits underlying the Tihama coastal plain and covers about 1275km2
(Adnan, 2002). Mesozoic complex is another main aquifer in Wadi Surdud upper catchment. This
aquifer is consisting of Tawilah sandstone and Amran limestone and covers an area around
1000km2. The initial storage for Quaternary and Mesozoic aquifers is estimated to be 2700MCM
and 1000MCM respectively (Adnan, 2002, Van der Gun, and Aziz, 1995). There is another less
important aquifer extends along Wadi Surdud reaches (Shallow aquifer) is very dependent on
Runoff and baseflow with initial capacity estimated to be around 500MCM. Surfacewater in Wadi
Surdud is in the form of runoff as excess of rainfall contributed by six mountainous agriculture subcatchments through six tributaries wadis (see Figure 3). This flow is divided into two parts: direct
flow and baseflow. Direct flow is associated with the channel precipitation, overland flow and
interflow. The baseflow is a regional aquifer system of Mesozoic sediments, drained by the so-called
Ayoun Surdud ("Surdud springs"). The baseflow rates of Wadi Surdud immediately downstream of
the confluence with Wadi Dayan are typically in the range of 18.92- 31.54 MCM/year, not counting
15
possible underflow through the wadi bed. Only some 10% of this baseflow is contributed by Wadi
Dayan (SAWAS, 1996). This baseflow is a vital source of water for the people living along the
wadi, and it is diverted at many locations along the wadi course to irrigate small plots of land on the
valley terraces. Due to return flows and other inputs downstream, the baseflow rate does not change
very much between Bab Dayan and Fug Alhusain, but is completely disappear after this location
through bed infiltration to Quaternary Aquifer (SAWAS, 1996). The average annual amount of
surface water involved (direct flow) is between 50 and 100 MCM/year. The average annual amounts
measured at Fug Alhusain until 1991 was 69.3 Mm3 (for details refer to Adnan, 2002, Van der Gun,
and Aziz, 1995, NWRA, 2008, SAWAS, 1996). This direct flow is almost utilized downstream of
Fug Alhusain at the Lower Catchment (Coastal area) by thirteen agriculture sub-catchments.
According to the 2004 Census, the population resides in coastal area is about 401961 inhabitant
with average growth rate 3.258% and in the mountainous area is 522519 inhabitant with average
growth rate 2.796%. It is assumed that at mountainous area domestic water use is 40l/c.d and in the
coastal area is 70l/c.d (Adnan, 2002).
8. Population
The total population of the project area reached 299,641 inhabitants according to 'The Final Results
of Population, Housing & Establishment Census, 2004'. The rural population rate is 80% and urban
population rate is only 20% that means more population is distributed in rural areas, while total male
rate is 51%. The main towns and urban centers are Az Zaideyah, Ad Dahi, Al Kadan, Al Meghlaf
and As Salif.. Figure 9 shows the population distribution in the wadi surdud area.
Well inventory study has been carried out in 2008, by NWRA; field works implemented by two
crews. Total number of wells has been inventoried around 4948 wells,. The inventoried wells are
classified into dug wells its number 1500, which represent about (30%); borehole wells 1835, which
represent about (37%); dug/bore wells 1604, which represent about (32%) and only nine springs,
which represent about (0.18% ) of total, where they located in Wadi Al Hawdh easting boundary of
Wadi Surdud plain . Figure 10 shows the wells distribution in costal plain of the wadi Surdud.
16
As Salif Urban
1,206
Al Munirah Rural
0%
32,741
10%
Al Munirah
Uraban, 8,127
2%
As Salif Rural,
5,485
2%
Al Meghlaf Rural
39,607
12%
Az Zaideyah
Urban 20,093
6%
Az Zaideyah
Rural, 86,501
25%
Al Meghlaf
Urban, 5,203
2%
Bajel Rural,
79,679
23%
Ad Dahi Urban,
25,473
7%
Ad Dahi Rural,
36,578
11%
Figure 9 Wadi Surdud Area Population Distribution 2007 (after NWRA, 2008).
Figure 10 Distribution of bore holes in Wadi Surdud Plain (NWRA,2008)
17
9. Methodology
In the case study area extensive stakeholder consultations and data collection were conducted to
characterize current water availability, future water resource vulnerability, and possible adaptation
strategies to mitigate water scarcity. Stakeholder consultations were undertaken using rapid rural
appraisal techniques and focused on local perceptions of water scarcity, climatic factors, and
development challenges; overall strategy preferences of various interest groups (e.g., farmers, policy
makers, water utilities officials) were collected based on perceived feasibility, cost, and value in
terms of water savings. These structured stakeholder discussions were then synthesized into a set of
inputs for water resource modelling and prioritizing adaptation initiatives.
Current water demand and supply data and estimated future trends in water use, obtained from a
number of Yemeni and international data sources, were incorporated into a scenario-driven water
balance modelling platform - the Water Evaluation and Planning (WEAP) software (Yates et al.,
2005). WEAP was used for each case study to analyze water availability for a number of adaptation
and climate scenarios, including a reference scenario (herein referred to as ‘Reference’) that projected
existing trends in water supply and demand into the future (2033) in the absence of adaptation
options. In the Reference scenario , the climate sequence for future years was developed by repeating
the sequence of available historical data and assuming a similar periodicity into the future period
(2008-2033).
In addition, two different climate change scenarios incorporated changes in precipitation and
temperature through 2032, as predicted by the Oregon State University model (OSU Core) and U.K.
Meteorological Office High Resolution General Circulation model (UKHI), developed during the
Netherlands Climate Change Studies Assistance Program (NCCSAP : 1996-2000). The OSU Core
model represented an ‘expected’ climate trajectory, whereas the UKHI model represented a ‘worst
case’, drier trajectory.
9.1 WEAP Model development
After compiling the necessary data, the WEAP model is used for water balance analysis of
Sana’a Basin. The schematic diagram is shown in Figure 11.
18
WEAP supports the use of three hydrologic modeling methods: the Rainfall Runoff method FAO
(Food and Agriculture Organization of the United Nations), the Water Requirement FAO
approach, and the Rainfall Runoff Soil moisture method. The Rainfall Runoff Soil moisture
method was chosen because it offers the most comprehensive analysis by allowing for the
characterization of land use and/or soil type impacts to the hydrological processes (Sieber, 2005).
The Soil moisture method is a one-dimensional two-soil-layer algorithm for calculating
evapotranspiration, surface runoff, sub-surface runoff and deep percolation for a defined land
area unit. A conceptual diagram of the equations incorporated into the Soil moisture method
water balance calculations are shown in Figure 12
Figure 11.Schematic diagram of WEAP model for Wadi Surdud drainage basin.
19
Figure 12. Soil moisture method Model (Source: Sieber, 2005)
Using the Soil moisture method which relatively accurately describes the hydrologic response of the
basin implies that more detailed hydrologic and climatic parameters are required for the model.
Consequently, the parameters and data are often difficult to define with certainty. The basic input
parameters are listed in Table 2, along with the sensitivities identified for each parameter, which are
a result of the work of Jantzen et al, (2006). WEAP imposes a model structure in terms of input
parameter resolution, meaning that WEAP forces certain parameters to describe the entire catchment
and others to describe smaller land unit areas such as the soil classification or land use category.
20
Table 2. Input Parameters and Sensitivity
Parameters
Unit
Resolution
Sensitivity
Land use
Area
Sq km
Catchment
High
mm
Catchment
Highi
Deep Conductivity
mm/day
Catchment
Moderate
Initial Z2
No unit
Catchment
No Influence
mm
Soil
Moderate
Root Zone Conductivity
mm/day
Soil
Moderateii
Preferred Flow Direction
no unit
Soil
Moderate
Initial Z1
no unit
Soil
No influence
Crop Coefficient, Kc
no unit
Land use
High
Leaf Area Index
no unit
Land use
High
Catchment
High
C
Catchment
Moderate
m/s
Catchment
Low
%
Catchment
Low
Deep Water Capacity
Soil Water Capacity
Climate
Precipitation
Temperature
Wind
Humidity
mm
o
Catchment Area
A fundamental parameter of any hydrologic model is the catchment area. The catchment areas of
the sub-basins delineated and measured in this study was found to be well in line with the previous
studies.
Deep Water Capacity
Deep Water Capacity is the effective water-holding capacity, in millimeters, of the deep soil layer or
the second bucket in the Soil moisture method.
21
Deep Conductivity
The Deep Conductivity parameter represents the conductivity rate of the second bucket, in
millimeters per day. Deep Conductivity controls the transmission of base flow. WEAP applies a
single value of Deep Conductivity to the entire catchment. This value is very low or zero in Sana’a
Basin as base-flow in the Wadis is negligible.
Initial Z2
The “Initial Z2” parameter is the relative storage given as a percentage of the total effective storage
of the Deep Water Capacity at the beginning of a simulation. WEAP, like Deep Water Capacity,
forces Initial Z2 to be constant for each basin.
Soil Water (Root Zone) Capacity
Soil Water or Root Zone Capacity is the effective water-holding capacity in millimeters of the first
bucket in the Soil moisture method.
Root Zone Conductivity
Root Zone Conductivity or soil conductivity is the conductivity in the first bucket. Conductivity
rate typically varies among soil and land use classifications.
Different values are assigned
depending on land use characteristics (runoff producing characteristics P1, A1, etc.) defined in
earlier sections.
Preferred Flow Direction
The Preferred Flow Direction parameter is used to partition flow out of the root zone layer to the
lower soil layer or groundwater. Preferred flow direction can vary by land use classification and
ranges from 0 to 1. A preferred flow direction of 1 indicates 100% horizontal flow direction while 0
indicates 100% vertical flow direction.
22
Initial Z1
The Initial Z1 parameter is the relative storage given as a percentage of the total effective storage of
the Root Zone Water Capacity at the beginning of a simulation.
Crop Coefficient Kc
The crop coefficient parameter Kc represents the effects of vegetative evapotranspiration and soil
evaporation, which vary by land class type. The parameter was created to study the required soil
moisture to maximize crop biomass production.
Hence, Kc is typically used to calculate the
required evapotranspiration using the equation:

(Evapotranspiration) required = Kc * (Evapotranspiration) reference,

Kc value adopted is used as presented in earlier sections.
Leaf Area Index
Leaf Area Index (LAI) is a parameter that varies by land use and is used to control the surface runoff
response. Runoff tends to decrease with higher values of LAI.
Precipitation
Monthly Precipitation values of all stations in Wadi Surdud catchment are used. The stations are
described in earlier sections.
Temperature, Wind and Humidity
Temperature data are entered in degrees Celsius. Humidity is the relative humidity entered as a
percentage and Wind values are entered in meters per second.
23
10. Climate input base line parameters
The historical average annual rainfall in the upper cachment (Figure 13) during the previous
twenty three years is not uniform and decreases with time which may attribute to climate change.
For the adopted simulation period (2008-2033) for Reference Scenario, a possible future rainfall
sequence was determined using the Water Year method using this historical data. Characteristic
water year statistics for very wet, wet, normal, dry, and very dry were determined from the 90th,
75th, 50th, 25th, and 10th percentile flows in this dataset. The ratio of each characteristic flow
relative to a normal flow obtained values of 1.34, 1.26, 0.81, and 0.66 for very wet, wet, dry, and
very dry years (1.0 being normal). For local precipitation in each sub-cachment, the average
monthly values were taken from the relevant rainfall stations recorded by Tihama Development
Authority (TDA) for the period 1984-2007. Two climate change scenarios were also used, the
UKHI dry weather and OSU Core which downscaled to local condition in the study area either the
mountainous or the coastal region. The UKHI scenario assume 23% decrease in rainfall in the
mountainous area and 27% decrease in rainfall in coastal area by the end of simulation period
(2033). The OSU Core scenario assumes increase in rainfall of 5% in the mountainous area and 9%
in coastal area by the end of simulation period.
500
450
Rainfall, mm/year
400
350
300
250
200
150
100
50
2007
2006
2005
2003
2002
2001
2000
1997
1996
1992
1991
1990
1989
1988
1987
1986
1985
1984
0
Year
Figure 13. Average annual rainfall of all stations in Upper Cachment (mountainous region)
24
11. Model calibration and results
The result of the base condition is compared with the observed (or reported) values then for
verification the model is calibrated. Table3 shows the calibration result where the model result is
very close to the observed values especially at coastal catchment except for sub-surface flow which
is assumed (Adnan, 2002; Van der Gun, and Aziz, 1995) to undergo to the Red Sea. In The Model
all the excess surface water infiltrates to the quaternary aquifer which even could not cope with
annual decrease in water storage (Figure 14 Table 3) which is about 288.62 MCM/year (0.23m
annual drop) and thus the existing storage will be depleted within 93 years during the Reference
Scenario and within 70 years during the UKHI Scenario (0.26m annual drop). In recent time due to
overexploitation from some places of western area like Al Urg, Al Jarb and Al Turbah areas, the
groundwater flow direction in these areas changed from all directions to the center of cone of
depletion and seawater intrusion hazard became more serious, where about 5000 borehole are in the
coastal area (NWRA, 2008). The conclusion is that groundwater flow pattern evidently related with
the aquifer deposits types and with the total abstraction from the aquifer (NWRA, 2008). For the
mountainous region the Model surface flow result is very close to the observed values while the
groundwater abstraction and recharge result is respectively about 21 and 12% more than the
estimated values by Adnan (2002) and Van der Gun and Wesseling (1991) which are based on
water balance method but not on real measurements. Data that could be used to determine the
recharge from precipitation is not available for the upper Wadi Surdud catchment. Also, information
on irrigation losses is scarce. Most of the studies are concentrated on coastal plain and thus a detail
study on upper cachment of Wadi Surdud is vitally needed especially on groundwater abstraction
and infiltration. Regarding groundwater storage it is nearly stable with just with about 1 to 2 cm
annual drop (Figure 16 during the Reference Scenario and will be more stable with no drop in
storage in the OSU Scenario but it will be affected during the UKHI Scenario especially in the
Mesozoic aquifer where the annual water storage drop will reach 10cm.
25
Table3: Comparison between the reported and the predicted Wadi Surdud' Model values
Surface water (average)
Ground water abstraction
Mm3/yr
Mm3/year
At
Catchments
Mountainous
Irrigation
sub-catchments
&
evaporation
Mountainous
Area
Model
Run
Base
along the
off
flow
wadi
45.65
25.298
1.646
At Fug
Alhusain
Total
Aquifer
Irrigation
Municipal
Recharge
14
8.52
36
16.8
8.52
*40.31
364.12
12.22
97
370.33
12.22
*93.93
surface
flow
Mesozoic
69.3
&
Shallow
46.274
25.3
1.604
69.97
At
Irrigation
At
&
Fug Alhusain
evaporation
along
coastal
Coastal Area
agricultural
Run
Base
off
flow
Lands
Assalif
area
(close to
Red
Sea)
Quaternary
Total
Subsurface
flow
Model
45.65
23.652
35
34.3
46.274
23.696
32.9
0
* Infiltration to aquifer from catchments, from wadi bed, from transmission links losses and municipal return flow
26
Billion Cubic Meter
Groundw ater Storage
Aquifer: Qaternary Aquifer, All months
OSU Core scenario
Reference
UKHI Dry Scenario
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Jan Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec
2008 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033
Figure14. Groundwater storage in the Quaternary aquifer under climate scenarios
Groundw ater Storage
Selected Aquifers (2/3), All months
OSU Core scenario
Reference
UKHI Dry Scenario
1,600
1,500
1,400
1,300
1,200
1,100
1,000
900
800
700
600
500
400
300
200
100
0
Jan Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec
2008 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033
Figure 15. Groundwater storage in the Mesozoic and shallow aquifers under climate scenarios
27
12. Strategies development and results
Three strategies were introduced to improve the irrigation efficiency during the Reference and
UKHI dry weather scenarios. These strategies are Using Drip Irrigation (assumes 30% gain of
water), Using Closed Conduits (assumes 15% gain of water), Rehabilitation of Traditional Irrigation
Channels (assumes 10% gain of water). In addition, there is another strategy, Changing Crop Pattern
by replacing Banana with Sorghum and Qat with Coffee. Generally, it can be seen in Figure 16 that
when these strategies are applied to all catchments during the Reference Scenario the most effective
strategy is drip irrigation followed by closed conduits then traditional irrigation channels. For drip
irrigation technique and in terms of storage improvement percentage, it is about 6.3% for the coastal
aquifer and 4.4% for the mountainous aquifers followed by closed conduits with half of those values
then Rehabilitation of Irrigation channels with third of those values. Changing crop pattern has very
limited effect where in terms of storage improvement percentage it is only 1.4% for the Quaternary
aquifer and 0.1% for the Mesozoic and Shallow aquifers.
This sequence of strategies is also evident in Figures 17 and 18 when they are applied under the
UKHI dry weather scenario but with less effect. The drip irrigation technique is very effective in
improving the storage capacity of the Quaternary aquifer in the coastal area (Figure 8) but less
effective for the Mesozoic and Shallow aquifers in the mountainous area. This is because the
agriculture sub-catchments in the coastal area are very dependent on groundwater than rainfall or
surface water (See Figure 19 & Table 3), while the reverse happens in the mountainous agriculture
sub-catchments (See Figure 20 & Table 3). Thus, during the UKHI dry weather scenario some
other strategies should be applied instead in the mountainous region such as construction of storage
facilities (dams, cisterns etc.) to capture the runoff.
28
Groundw ater Storage
All Nodes, All months
Changing crop pattern
OSU Core scenario
Reference
Rehabilitation traditional irrigation channels
UKHI Dry Scenario
Using closed conduits for irrigation
Using drip Irrigation
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Jan Mar Jun Sep Dec Mar Jun Sep Dec Mar Jun Sep Dec Mar Jun Sep Dec Mar Jun Sep Dec
2008 2009 2010 2011 2012 2014 2015 2016 2017 2019 2020 2021 2022 2024 2025 2026 2027 2029 2030 2031 2032
Figure 16 Strategies effect on all aquifers storage during the Reference Scenario
Groundw ater Storage
Aquifer: Qaternary Aquifer, All months
Changing crop pattern
OSU Core scenario
Reference
Rehabilitation traditional irrigation channels
UKHI Dry Scenario
Using closed conduits for irrigation
Using drip Irrigation
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Jan Mar Jun Sep Dec Mar Jun Sep Dec Mar Jun Sep Dec Mar Jun Sep Dec Mar Jun Sep Dec
2008 2009 2010 2011 2012 2014 2015 2016 2017 2019 2020 2021 2022 2024 2025 2026 2027 2029 2030 2031 2032
Figure 17 Strategies effect on the Quaternary aquifer storage during the UKHI Scenario
29
Groundw ater Storage
Selected Aquifers (2/3), All months
Changing crop pattern
OSU Core scenario
Reference
Rehabilitation traditional irrigation channels
UKHI Dry Scenario
Using closed conduits for irrigation
Using drip Irrigation
1,600
1,500
1,400
1,300
1,200
1,100
1,000
900
800
700
600
500
400
300
200
100
0
Jan Mar Jun Sep Dec Apr Jul Nov Feb May Sep Dec Mar Jul Oct Feb May Aug Dec Mar Jul
2008 2009 2010 2011 2012 2014 2015 2016 2018 2019 2020 2021 2023 2024 2025 2027 2028 2029 2030 2032 2033
Figure 18 Strategies effect on Mesozoic and Shallow aquifers' storage during the UKHI Scenario
30
Demand Site Inflow s and Outflow s
Scenario: Reference, All months, Selected Demand Sites (14/21)
Consumption
Inflow from Qaternary Aquifer
Inflow from Wadi surdud
Outflow to Qaternary Aquifer
Precipitation
350
300
250
200
150
100
Million Cubic Meter
50
0
-50
-100
-150
-200
-250
-300
-350
-400
-450
-500
-550
2008
Figure 19: Coastal catchments inflows and outflows
Demand Site Inflow s and Outflow s
Scenario: Reference, All months, Selected Demand Sites (7/21)
Consumption
Inflow from Mesozoic Aquifer
Inflow from Shaloow aquifer
Outflow to Fug Alhusain
Outflow to Mesozoic Aquifer
Outflow to Shaloow aquifer
Outflow to Wadi Alahgur
Outflow to Wadi Dyan
Outflow to Wadi Kasaba
Outflow to Wadi Rugum
Outflow to Wadi Sara
Precipitation
All Others
650
600
550
500
450
400
350
300
250
Million Cubic Meter
200
150
100
50
0
-50
-100
-150
-200
-250
-300
-350
-400
-450
-500
-550
2008
Figure 20: Mountainous catchments inflows and outflows
31
13. Adaptation strategies prioritization based on stakeholder criteria weighting
Based on analysis of the collected data on water vulnerability in the case study area and the
stakeholder consultation findings several adaptation strategies which address water scarcity in the
case study area were identified. A WEAP application for the study area was then developed based
on the collected data such as, water use sectors and consumption (domestic and agriculture),
available conventional and unconventional water resources (ground water, surface water,
wastewater), land use, future projection of (population, agriculture area) climate parameters
(rainfall, temperature, humidity, wind etc.) and climate change trend.
The results of the WEAP application in terms of water saving as evaluating criterion are arranged in
respected manner as follows:
1. Using drip irrigation
2. Using closed conduits
3. Rehabilitation of traditional irrigation channels
4. Changing crop pattern
From the previous result it can be seen that each strategy could be adopted to alleviate water scarcity
but in terms of affordability the situation certainly will be different. Therefore, the stakeholder
consultation is one of the main activities which are needed in order to discuss their concerns
regarding issues of water scarcity in the study area and suggested strategies. Meetings were
conducted with ten stakeholders and decision makers in the case study area to evaluate the suggested
strategies in terms of the following:
a. Capital cost (implementation cost)
It includes cost of infrastructure implementation (building, instruments, rehabilitation,
further treatment, conducting training or awareness campaigns etc.)
b. Maintenance cost
Cost to maintain infrastructure in a good condition to insure sustainability
c. Quantity of water saving
The quantity of water can be offered by an adapted strategy
32
d. Sustainability
The infrastructure life time of an adapted strategy with a proper maintenance.
e. Knowledge to implement and maintain
Eligibility of a stakeholder to implement and maintain a strategy
f.
Preservation of local practice and lifestyle
To which extent an adapted strategy, compared to another, can insure that a stakeholder will
continue his existing way of living without shifting to another job.
A structured questionnaire was prepared addressing the adopted strategies and their evaluation
criteria (Annex A). First, the purpose, the structure of the questionnaire and the adapted strategies
were explained to the stakeholders associated with the WEAP application criteria results of water
quantity saved and number of years each strategy can cope with demand. After discussion with the
stakeholders the information provided were filled into the questionnaire, in addition to any provided
remarks, complains and reservations. The result of stakeholder consultations regarding the suggested
strategies and evaluation criteria are summarized in Table 4. This information were analyzed with
changing the qualitative information into qualitative values and then input into the MCA-WEAP
(Model 4 in the Annex A) for determining preferences and prioritization for adaptation strategies.
13.1 Discussion of results:

Changing crop pattern
It can be seen from Module 6 that changing crop pattern from Qat to coffee trees have high
priority than others strategy though the applied area is about 255.1 ha which is just 1% of the
suggested irrigated area by drip irrigation or using closed conduits (24413 ha). This is
because water saved by replacing Qat trees in this tiny area is very high i.e. about half what
is saved by the area suggested for closed conduits strategy which is 96 times bigger. This
reflects the huge amount of water consumed by Qat trees (up to 90% of total irrigation
water).

Conveying irrigation water through closed conduits
For improving irrigation efficiency this strategy come in the same rank with drip irrigation
method. However, this method is more practical and less expensive than drip irrigation
method. This is because the closed conduits are usually plastic pipes or fabric pipes, though
33
in the latter some of the irrigation water is evaporated from fabric skin. This practice has
already been practiced by some farmers and it is, comparatively, easy to afford, implement
and maintained.

Using drip irrigation
This strategy is the best in terms of water saving and sustaining the farmers existing life style
but more expensive compared with closed conduits strategy as it contains some sophisticated
tools (pumps, drippers, regulators etc.) which needs some training on operation and
maintenance. If this strategy is subsidized it will be then the best in terms of water saving
and can be afforded by a wide sector of farmers which are mostly poor.

Rehabilitation of irrigation channels and structures
This strategy is the last one in ranking though it is the most practiced strategy in the study
area. This traditional method costs farmers lots of money every year to maintain irrigation
channels and structures in a good condition. In addition, the life time of rehabilitated
channels and irrigation structures is very short compared to other aforementioned strategies
especially when they are subjected to frequent flush floods.
34
14. Policy and Institutional Issues
14.1 Institutional set up
Recognizing climate change threats, the government of Yemen ratified the United Nations
framework Convention on Climate Change (UNFCCC) on 21 February 1996 and
immediately initiated a process to meet its commitments under the Convention. With the
GEF/Netherlands financial/technical assistance (1997-2001), the GOY completed important
enabling activities for climate change including, the Initial national communication (INC),
and currently the Second National Communication (SNC) is underway and about to be
finalized (2008-2010).
The creation of the Ministry of Environment & Tourism (now Ministry of Water and
Environment) in May 2001 (Decree No. 46/2001) constituted an important step. By lifting
environmental concerns to cabinet level, it has raised hopes that environment protection will
receive better attention in the future.
In June 2001 the Environment Protection Council (EPC) was replaced by the Environmental
Protection Authority (EPA) (Decree No. 99/2000). This “new” agency is entrusted with a
wider mandate, including the formulation of policies, strategies and action plans, drafting
and implementation of pilot programs, drafting of environment-related laws and by-laws,
provision of technical feed back and advice on regional and global environmental
conventions, coordination, monitoring and evaluation of activities of different
environmental protection agencies, establishing of contacts with regional and global
agencies dealing with environmental issues, and implementation of a public awareness
program.
The Government of Yemen has made important steps for setting a comprehensive
development strategy both on the policy as well as the institutional framework levels. The
MDG needs assessment and the Third National Development Plan for Poverty Reduction
have established national development priorities and are expected to guide future efforts.
The National Environmental Action Plan (NEAP) is in the process of updating. The role of
35
the EPA has been strengthened by the incorporation of the Minister of Water and
Environment into the Cabinet, stronger coordination functions and an expanded mandate.
The government of Yemen is intending to develop a new policy framework that has the
strength and components of meeting the country needs, including enhancing governance
through decentralization and public participation; social investment and poverty reduction
targeting vulnerable sectors and the rural poor; preserving the environment by rationalizing
water use and combating desertification; and ensuring effective monitoring and evaluation,
follow-up and donor coordination systems, among others.
UNDP’s support to Yemen in terms of sustainable environmental development has focused
assistance towards compliance with international environmental conventions, aiming at (a)
promoting environmental governance in mainstreaming sustainable development and
implementing relevant policy, legal and regulatory measures, and (b) capacity development
to implement global environmental conventions primarily through UNDP-GEF portfolio for
Climate Change, the Yemen’s Initial National Communication to the UNFCCC (19982001),
Top-up
Enabling
Activity
(1999-2001)
and
Yemen’s
Second
National
Communication to the UNFCCC (2008-2010).
At present, two UNDP/GEF projects are supporting the government of Yemen to address
the issue of climate change in Yemen; 1)National Adaptation Action Plan (NAPA) has been
prepared to broadly communicate to the international community priority activities that
address Yemen’s urgent needs for adapting to the adverse impacts of climate change. 2)
National Capacity Self Assessment (NCSA) is preparing national strategy and action plan
for addressing capacity constraints faced by the GOY to respond to the global conventions
including the UNFCCC.
The Ministry of Water and Environment (MWE), along with its acting authorities, are
currently the main responsible parties and coordinators for implementing water and
environment policies. In reality, the actual implementation of policies depends on a wide
range of entities from both public and private sectors, on national and local levels. The
36
MWE makes efforts to integrate the water and environment policy into other policies
developed by the country, through establishment of closer coordination and cooperation
with other ministries and authorities. In response, the other authorities/relevant bodies have
shown their willingness to accept their responsibility for implementing the water and
environmental protection plans in their sectoral policies, and to include it in the overall
development policy of the country. The integration of the water and environment policies in
other policies as a process is becoming more intensive and more comprehensible now than
before, and is reflected in the strategic and programme documents adopted by concerned
authorities in the country.
In accordance with its responsibilities, the MWE carries out regular collection, processing,
formatting, and proper keeping of the data from monitoring networks of all water and
environment media in areas of air, water, soil, noise and waste. It also submits data to the
UNFCCC and other relevant international organizations.
The Ministry of Planning and International Cooperation (MPIC), along with other
concerned international organizations, for example ESCWA, are currently leading the
process of development of National Set of Environmental Indicators for Yemen Republic.
Working Groups have been formed for verification and supplementing the indicators for the
objective of their final adoption for the chapters: air, biological diversity, climate change,
soil, waste, water, agriculture, energy, fishery, transport, health, and tourism. Specifically
for climate change, the Yemen Republic ratified the UN Framework Convention on Climate
Change (UNFCCC), Kyoto Protocol. The MPIC coordinated all activities related to
ratification of the Convention and Protocol including activities on raising public awareness
During the preparation of Yemen’s Initial National Communication to the UNFCCC (19982001), the Climate Change Unit (CCU) was set up within the Environment Protection
Authority (EPA). Furthermore, more recently, a National Climate Change Committee
(NCCC) was established as an advisory body for policy-making related to climate change
issues. It is composed of key governmental agencies. However, such committee has not yet
included academia non-governmental organizations and private entities.
37
14. 2 Strategic, legislative and policy issues
In addition to the institutional set-up, the Yemen Republic in addressing climate change is
focusing its activities at several levels: strategic, legislative, regional, bilateral, and
multilateral levels. At a strategic level, the climate change issue was included in the National
Environmental Action Plan (NEAP). Furthermore, the Government of Yemen has recognized
the possibilities for achieving the goals of economic, social, and sustainable development, as
well as those for transfer of knowledge and technologies and promotion of environmental
investments through the implementation of the Clean Development Mechanism (CDM) of
the Kyoto Protocol. The CDM practical application lies in its contributing to the general
commitment of the Government of Yemen towards attraction of investments, in this case
manifested through "environmental investments". In 2007, the Government has adopted a
program for the first commitment period 2008-2012 according to the Kyoto Protocol. Carbon
financing is treated as an additional source of financing within a national strategy for
environmental investments.
At the legislative level, climate change issues are yet to be incorporated within amendments
for the law on environment, including details on preparation of inventories of GHG
emissions and removals by sinks as well as an action plan on measures and activities to abate
increase of GHG emissions and to mitigate the adverse impacts of climate change. In future
amendment of the law on environment, it is stipulated that a national plan for climate change
be adopted, for the purpose of stabilization of GHG concentration at a level that would
prevent any dangerous anthropogenic impact on the climate system within a timeframe
sufficient to allow the ecosystems to naturally adapt to the climate change, in accordance
with the principle of international cooperation and the goals of the national social and
economic development. In addition, provisions on the Clean Development Mechanism will
be introduced into the amended law on environment.
For the purpose of providing consistent and coordinated implementation of the policy in the
areas of its competence, except for the regular annual programming of the activities, the
MPIC has adopted the Third Strategic Development Plan for the period 2006-2011. The plan
38
contains precise strategic objectives and environmental priorities, as well as activities for
their realization for the five-year period. Special attention is given to the development
element, and to the identification of the necessary human and financial resources that will
enable feasible implementation of the plan.
At the strategic level, environmental policy in Yemen (as a component of sustainable
development policy as well as by itself) is covered by the following documents: National
Strategy for Sustainable Development (NSSD) and the Second National Environmental
Action Plan (NEAP). Evidently, if not yet accomplished, the principles of sustainable
development need to be incorporated in the constitution of Yemen, as an amendment, as well
as their incorporation into the law on environment.
The National Strategy for Sustainable Development (NSSD) has recently been implemented
(2008) through UNDP-Yemen, and in coordination with EPA. The strategy identifies several
key driving priorities for making Yemen Republic sustainable: Arabian Gulf Council (AGC)
membership, establishing a policy and legal framework (as the backbone of any strategy
development
and
implementation),
administrative
and
enforcement
capacity
for
environmental improvement, structural changes in energy pricing, comprehensive strategic
work and plans in rural development; identification of unemployment as a key social issue
and identification of small and medium-sized enterprises, infrastructure, and industry as solid
industrial groundwork..
A National Water Resource Strategy for the country has been developed and is well under
implementation. It is considered as a key priority and driver for many other systems and
sectors. Thus, adaptation issues in water sector can be considered as a priority, taken in
account climate change conditions and risks in future.
Adaptation measures related to water resources are divided into two major classes:
adaptation of the supply and adaptation of the demands. The first class is linked to the
reduced available water resources and the other one to the increased water demands. The
supply adaptations mainly could be realized through rehabilitation of the existing physical
39
infrastructure, construction of a new water infrastructure, and adapted management of the
existing water management systems to climate change conditions. The demand adaptation
can be implemented by improved efficiency, technological change, and market/price-driven
transfers to other activities. All types of measures, classified into two groups – structural
(hard engineering solutions) and non-structural – can be presented for each domain of
intervention (irrigation, water supply, flood and droughts, erosion and sedimentation, water
resources management, monitoring, and water quality). Some of the adaptation measures that
are considered as intersectoral are presented in this report. The high priority adaptation
measures that were not considered in this report and need to be accounted in future studies
are the following:
- Implementation of improved design standards for each domain of adaptation
intervention.
- For example, in the domain of irrigation and water supply for the population:
reducing of the water losses by reconstruction of the water delivery network of both
irrigation and water supply systems; implementation of water efficiency schemes;
water pricing; credit facilities; insurance. For water supply, adaptation measures
are: use of a dual water supply network and other sources of water (for drinking and
for technical purposes – watering parks and lawns, washing the streets, etc.);
recycling of water for non-potable use and construction of new water supply
systems in rural areas.
- For floods and droughts, the following adaptation measures are necessary:
rehabilitation of the existing and construction of new flood protection and drainage
systems; improvement of forecasting system; adaptation of the operational
management practices of the capacity of the reservoirs to the climate change
conditions including droughts and floods; upgrade of wastewater and storm-water
systems; preparation of flood defense and protection plans; initiating insurance
schemes against flood and drought damage.
40
- Measures for the domain of erosion and sedimentation include: reforestation of
upstream basin catchments; technical protective measures for torrent regulation and
regular dredging of the sediments from dams and reservoirs
.
- In the domain of water resources management, the following structural measures
are suggested: increase of reservoir capacities; integration of separate reservoirs
into a single system; construction of new dams (reservoirs); and water transfer from
one drainage basin to another or within a drainage basin (for example, from MaribAl-Juff area to Sana'a Basin, or from Surdod basin to Al-Mahweet and Twilah
urban highland areas).
63
- The most successful structural adaptation measure in the domain of water quality is
the construction of wastewater treatment plants, especially for the larger cities in
the country.
- The structural measures for adaptation in the domain of monitoring are needed: they
lead to improvement of data processing; implementation of the predictive models in
real time; and strengthening of the capacities of the institutions responsible for
monitoring and provision of sufficient funds on a regular basis for monitoring
activities.
- For the purpose of illustration, some examples of dealing with institutional and
legal measures and identification, assessment and mitigation of negative climate
change impacts, were given in Tables 5 and 6.
14.3 Constraints and Gaps for Vulnerability Assessment
Several major constraints and gaps were identified during preparation of this study on the
vulnerability assessment. The most persisting one is a problem of data availability,
consistency, and transparency. Existing monitoring stations in climate and groundwater
conducted by the Meteorological agency and Hydro-Service in the country are facing
permanent problems in organization and dissemination of data, especially when dealing with
41
the meteorological agency of the country, the only agency that has the ability and capacity to
update government units and concerned agencies with climate data, free of charge or with
little charge. In addition, some other problems exist, for example, slow modernization of
equipments and limitation of monitoring network stations, etc. Therefore, improvement of the
hydrological monitoring stations (for surface and especially for groundwater) including
stations for monitoring the water quality, improvement of the data processing, implementation
of the predictive models in real time and modernization of the equipment (in the field, in
laboratory, software, and hardware) are of the highest importance in the near future.
Soil monitoring does not exist in the country, as well as real groundwater monitoring through
observation and peizometric wells. Basic maps and databases are limited, and the existing
ones are quite old and some are unavailable (vegetation maps, land-use map, etc.). There is a
need for increasing the technical capacities for monitoring and updating of basic data sets.
Modern tools for vulnerability assessment are needed almost in all vulnerable sectors
(hardware, software, and training of personnel). Training of experts in modern technologies
for adaptation is also requested, although some short training sessions have been offered to
some national experts, through the implementation of NCAP project by UNDP and EPA, and
with coordination with WEC, during the year 2006 and 2007 .
Determination of the climate system components should be established by setting of a new
and modern climate observing system which would be established over the whole territory of
the Yemen Republic, that is, in all climatic areas, as well as by all climate parameters. It
means that an automated climate observing system should be established by which the
following climate system components would be performed in every moment and their
changes: daily, ten-day period, monthly, seasonal, annual, and many-year period in all
climatic areas in Yemen Republic.
Establishment of an automated climate observing system in Yemen, as well as in other
countries is necessary because of the following aspects:
42
1. Measurements and observations should be performed in a unique and non-subjective
way;
2. Investigation of data homogeneity should be performed as well as testing of the quality
of obtained information;
3. Information should be delivered to the Climate Change Unit (CCU) or other
established national climate centers, daily by special climate telecommunication units
or by Internet communications tools;
4. The way of data processing should be performed by unique methodology of
processing;
5. Results of the measurements should be delivered to the public precisely, and they
should be comparable with other average climate data which are available at each
meteorological station in all climatic areas in the Republic of Yemen;
6. Information should be accessible to the public by internet and its exchange should be
also performed for the necessity of other users and media.
14.4 List of Projects or programs proposed for financing
In the process of preparation of the case study data and upon the analysis of adaptation
elements and strategies, some priority projects were identified and listed below, for water
resources sector and adaptations and for other related sectors.
For the water resources sector, the projects proposed for future financing are:
- Adaptation Measures for Reducing Vulnerability to Climate Change of the Irrigation
System in the drainage basins of Wadi Surdod, Wadi Zabeed, and Wadi Moor, in
Hudeidah Governorate.
- Development of a Reliable Methodology for Groundwater Vulnerability Assessment
in Yemen Republic, under Climate Change Conditions, based on previous climate
change research and current case studies conducted on some basins.
- Development of Adaptation Measures to Combat Negative Effects of Climate
Change in Agricultural Production in Yemen Republic.
43
Table 5. Institutional and legal measures
Problem
Identified
No
approximated
Legislation and
strategic
development
documents
from climate
change aspect
1
Measures
Legislation
approximation and
strategic
development
documents from
climate change
aspect
Actions
Incorporate climate change
adaptation measures in:
- Spatial plan
- Agricultural strategic
development documents
- Strategic and planning
documents stemming
from the water law
(development of national
strategy on water,
finalization of water
master plan, and drainage
basin management plans,
including change of
available and demanded
water resources due to
climate change impacts,
priority by-laws)
- Physical and urban plans
- Strategic impact
assessment
- Action plan on
environment and
children's health
44
Responsible
party
MPIC, MAI,
MWE,
MOH, MOT
Time frame
2011/2012
Table 6. Measures for identification, assessment and mitigation of negative climate change impacts
Problem
Identified
Data
unavailability for
all sectors
Continuous data
collection, development
of databases and their
management
2
Climate change
vulnerability
3
Responsible
party
Time
frame
Development of database of
extremes (droughts and
floods)
MWE, MOH,
MPIC, MAI
2011/2013
Preparation of basic maps in
GIS format to a scale of 1:
50,000 (soil, vegetation,
erosion. ..etc
MWE, MAI,
MOMR
2011/2013
Measures
Adaptation measures
Actions
Development of adaptation
programme on climate
change in forestry sector
Production of native species
plants and
afforestation of hundreds of
hectare of bare land per year
Identification and
introduction of species
resistant to climate change,
implementing measures for
agricultural support
Introducing adaptation
measures and techniques
concerning climate change
(organic matter
turnover/water protection
and agro-techniques) Bura'a
directorate
Modernization of irrigation
systems
45
MWE, MAI
2011/2013
MWE, MAI
2011/2013
MWE, MAI
2011-2015
MAI,
2011-2013
MWE,
2011-2014
15. Conclusion and recommendations
The study area has special social and economical importance because it includes major
agricultural activities which support many cities beyond local borders with verity of crops. By
analyzing current and future water resources vulnerability due to climate change and driving
various water demand sectors it can be concluded that:

The area generally suffers from escalating pressures due to the high consumption of water by
agriculture in order to cope with increase demand by the population increase in crops
demanding cities.

The dominant water consumption in the coastal area is agriculture which consumes 97% of
the abstracted ground water and only 3% for municipal use. Up to date there is more than
5000 borehole in the coastal area alone which eventfully leads to overexploitation of
groundwater unless some strategies to stabilize water supply and demand patterns are
introduced.

At the present time, annual withdrawals from the Quaternary aquifer exceed renewable
resources where the annual drop in water depth reaches 0.3m and will likely to continue into
the future in the absence of a vigorous policy intervention.

In the mountainous region it seems that groundwater is nearly stable due to higher rainfall
compared with coastal area which leads the people to rely more on rainfall as main source
for agriculture and groundwater as a supplementary source where 66% of abstracted water is
used for agriculture and 33% for domestic purposes.

The climate variability and climate change is less influential than current and predicted
patterns of agricultural and household water consumption.

The choice of adaptation strategy depends on the influencing conditions of the particular
case study region, including both physical and stakeholder inputs.

For the coastal area the implementation of drip irrigation was identified as the best strategy
in terms of water savings and application of water on farmlands followed by conveying
irrigation water through closed conduits. As the majority of farmers are poor and barely
coping with existing living costs, subsidization or donor support would be needed for
implementation.
46

For the mountainous region, improved efficiencies through drip irrigation and improved
water distribution systems will have demonstrable effects when combined with other
supporting adaptation initiatives such as water harvesting/diverting structures (e.g. dams,
cisterns etc.).

Farmers along the wadi reaches identified improving indigenous methods (e.g.
Rehabilitation of traditional irrigation channels) for wadi flow use as the highest priority
initiative. The farming communities along this wadi are well aware of the need to harvest
wadi storm flows.
47
Table 4: Summary results of scenarios analysis and stakeholders meetings-Wadi Surdud
Adaptation Strategy
Cost of implementation
Sustainability
Criteria for Evaluating Strategy
*Water saving
Preserves local
practice and lifestyle
Knowledge to implement and
maintain
Using drip irrigation
high ($800-1000) per hectare
(total $21,972,150) required
for purchasing of equipments,
implementation and training.
high (long lifetimes for equipments with
proper maintenance up to 15 years),
.
(Increases crop yields by 20%)
Very high (technique saves 157,291,920 m3 per year
compared to business as usual;
(assuming 25% of water reused)
high; farmer continue as
they have for
generations
Medium: with enough training
farmers can implement and
maintain the system. Some
farmers already have such a
system
Using closed conduits
medium ($600-700) per
hectare (total $16,868,775)
required to purchase pipes and
install them
medium ($700-800) per
hectare required (total
$21,994,500) this includes
sediment removal and
rebuilding the destroyed
channels and lining with
cement mortar; in addition
protection with gabions if
needed
High($1200-1500) per hectare
(total $344,385) required to
purchase remove Qat trees and
plant Coffee plants
high (long lifetimes for pipes with proper
maintenance up to 20 years)
high (technique saves 91,058,000 m3 per year compared to
business as usual
medium; farmers
continue as they have
for generations
Medium: many farmers already
implemented such a system and
well maintained
medium; farmers
continue as they have
for generations
Low: all the farmers are
familiar with this traditional
irrigation system, and
practicing and maintaining it
for centuries
high; farmers continue
as they have for
generations
High: all the farmers are
familiar with this method
Rehabilitate traditional
irrigation channel
Changing crop
patterns
aData
low (less lifetime 5-10 years where damage of
rehabilitated channels depends on frequent
high floods.
(assuming 15% of water reused)
medium (technique saves 66,346,800 m3 per year compared
to business as usual
(assuming 10% of water reused)
High, long life time with adequate service up
to 40 years
low; saves 44,925,240 m3 per year compared to business as
usual,
appearing obtained from WEAP modeling.
48
Acknowledgment
This study was financed by the United Nations Development Programme (UNDP) which aims
at assisting Yemen with the enabling activities necessary to prepare and report the Second
National Communication to the Conference of Parties (CoP) in accordance with guidance of
the UN Framework Convention on Climate Change (UNFCCC). The study is implemented
under supervision of the Environmental Protection Authority in Yemen (EPA). The authors
would like to thank Eng. Mahmoud Shedewah, the chairman of EPA Yemen and Eng. Anwar
Noaman, the head of the climate change unit for their support.
49
References
Adnan, M. 2002. Water resources management in arid/semi-arid basins. PhD thesis, Cairo
University, Cairo, Egypt.
CSO, 2008 .Statistical Yearbook 200. Central Statistical Organization (CSO), Ministry of
Planning & International Cooperation, Yemen.
FAO,1989 .Crop stage growth and Crop Coefficients. FAO Irrigation and Drainage Paper
No.24.
IPCC (2007) Climate Change 2007. Climate Change Impacts, Adaptation and Vulnerability.
Summary for Policymakers. Working Group II Contribution to the Intergovernmental
Panel on Climate Change Fourth Assessment Report, Geneva, Intergovernmental Panel on
Climate Change.
MOAI, 2007 .Agricultural Statistics, Year Book 2007. General Dept. of Agricultural Statistics
& Documentation, Ministry of Agriculture & Irrigation (MOAI),Yemen.
NWRA, 2008 .Well inventory in the Tihama plain (Wadi Surdud). National Water Resources
Authority (NWRA), Ministry Of Water And Environment, Yemen.
O’Brien, K., Sygna, L., and Haugen, J. E. (2004) Vulnerable or Resilient? A Multi-Scale
Assessment of Climate Impacts and Vulnerability in Norway, Climatic Change 64(1-2)
193-225.
SAWAS, 1996, "Surface Water Assessment of Upper Wadi Surdud", Technical Report No 10,
National Water and Sanitation Authority (NWSA), Yemen, and TNO Institute of Applied
Geoscience, Delft, the Netherlands.
Sieber J, Swartz C and Huber-Lee A (2005) Water Evaluation and Planning System User
Guide for WEAP 21. Stockholm Environment Institute. Tellus Institute, Boston,
Massachusetts.
Smit, B. and Wandel, J. (2006) Adaptation, Adaptive Capacity and Vulnerability, Global
Environmental Change 16 282-292.
Van der Gun, J.A.M. , 1986. Water resources of the Wadi Surdud area. Main report. Report
WRAY-4, YOMINCO/TNO, Sana'a/Delft.
Van der Gun, J.A.M., and Wesseling, H., 1991. Water resources of the Wadi Surdud area:
pilot study on water resources management. Report WRAY- 22, GDWRS/TNO,
Sana'a/Delft.
Van der Gun, Jac A.M. , and Abdul Aziz Ahmed, 1995. The Water Resources of Yemen. A
summary and digest of available information. Report WRAY-35. MOMR, General
Department of Hydrogeology, Sana'a, Republic of Yemen, and TNO Institute of Applied
Geoscience, Delft, The Netherlands.
Yates, D., et al., 2005. WEAP21 – A demand, priority, and preference driven water
planningmodel. Part 1: Model characteristics. Water International, 30 (4): 487-500.
50
Annex A
51
Module 4: Evaluation Criteria
Summary of evaluation criteria
Menu
Start page
List of criteria
Type
score of 1 to 100
Short name
Descriptive Name
Type of measurement unit
Measurement unit
cost to build it
Quantitative; low score best
Thousands US Dolars
cost to maintain it
Quantitative; low score best
Thousands US Dolars
Physical Water saving
water saved when a strategy is adopted
Quantitative; high score best
Million m3/year
Physical Sustainability
life time for adopted strategy
Quantitative; high score best
years
Physical Applicable land
Land applied under a strategy
Quantitative; high score best
hectares
Module 1: Vulnerability
Economic Capital cost
Module 2: Stakeholders
Economic Maintenance cost
s1
ls1
Module 3: Initiatives
Module 4: Criteria
Module 4: Criteria list
Module 5: Weighting
Social
Knowledge to
implement &
maintain
the amount of learning required to implement the
strategy
Qualitative (1-100); high score best
score of 1 to 100
Social
Preserving local
livelihood
farmers continue reasonably their way of living
Qualitative (1-100); high score best
score of 1 to 100
Module 6: Ranking
Module 7: Help,
Reports
Exit
52
Module 4: Evaluation Criteria
Criteria scores (central estimates)
Menu
Start page
Module 1: Vulnerability
Module 2: Stakeholders
Module 3: Initiatives
Module 4: Criteria
Module 4: Criteria
Scores
Module 5: Weighting
Module 6: Ranking
Module 7: Help,
Reports
Exit
click here to enter a range
i
Enter criteria scores
Criteria short
Maintenance
Capital cost
Water saving Sustainability
cost
name>>>
Applicable
land
Knowledge to
implement &
maintain
Preserving
local
livelihood
Type of
Quantitative; Quantitative; Quantitative; Qualitative (1- Qualitative (1Quantitative; Quantitative;
high score
high score
100); high
100); high
measurement low score best low score best high score
best
best
best
score best
score best
unit>>>
Thousands
Thousands
US Dolars
Million
m3/year
years
hectares
22000
1100
66.34
10
29326
100
45
21000
1000
157.3
15
24413.5
0
90
Using closed conduits
17000
850
91
20
24413.5
90
60
Changing crop Pattern
344
30
44.9
40
255.1
95
30
Units >>> US Dolars
Rehabilitation of
traditional irrigation
structures (channels)
Using drip irrigation
method
53
score of 1 to score of 1 to
100
100
Module 6: Ranking of Iniatives
Total central scores
Menu
Start page
Module 1: Vulnerability
Module 2: Stakeholders
Results
Criteria short
Maintenance
Capital cost
Water saving Sustainability
cost
name>>>
Criteria weighting
>>>
very high
(17%)
Applicable
land
Knowledge to
implement &
maintain
Preserving
local
livelihood
very high
(17%)
very high
(17%)
high (13%)
very high
(17%)
average
(10%)
average
(10%)
very strong
very strong
strong
strong
average
average
Total central
score
0
0
7
3
17
10
5
42
0
1
17
5
14
0
9
45
Using closed
conduits
0
1
10
7
14
9
6
46
Changing crop
Pattern
17
17
5
13
0
10
3
64
Module 3: Initiatives
Module 4: Criteria
Module 5: Weighting
Module 6: Ranking
Module 6: Central
scores
Module 7: Help
Save and exit options
Stakeholder
very strong
consensus >>>
Rehabilitation of
traditional irrigation
structures
(channels)
Using drip irrigation
method
54
Module 6: Ranking of Adaptation Initiatives
by central scores
Menu
Final ranking (by central scores)
Start page
Total
central
score
Module 1: Vulnerability
Initiative \ Score
Module 2: Stakeholders
Changing crop Pattern
64
Module 3: Initiatives
Using closed conduits
46
Using drip irrigation method
45
Rehabilitation of traditional irrigation structures (channels)
42
Module 4: Criteria
Module 5: Weighting
Module 6: Ranking
Module 6: Rank
(central)
Module 7: Help
Save and exit options
55
Implementation
costs
Maintenance
cost
ُEvaluation criteria
Water Sustainability
saving
Adapted strategies
(Infrastructure
life time)
Thousand Dollars
Rehabilitation of traditional irrigation
channels
Using drip irrigation method
Using closed conduits
Changing crop pattern
Thousand
Dollars
MCM/y
years
66.34
157.3
91
44.9
Weight 1-5
56
Preserving
local
livelihood
1-100
Knowledge
to
implement
and
maintain
1-100
Remarks
Annex B
Photographs
(Only 2 photographs were included in this document. For obtaining the rest of the photos,
please refer to the preliminary draft submitted at earlier time)
57
Picture 1: Wadi Surdud base flow and water use upstream of Khamees Bani Sa'ad
Picture 5: Meeting with Farmers in Khamis Bani Sa'ad
58
59