Ministry of Regional Municipalities & Water Resources
Dams in Oman
2012
Ministry of Regional Municipalities & Water Resources
Dams
in the Sultanate of Oman
2012
www.mrmwr.gov.om
HisMajesty Majesty Sultan Sultan Qaboos Qaboos Bin His Bin Said Said
His majesty Speech Of all the Gifts with which God has blessed us, water is the greatest. It must be cherished and husbanded. Every effort must continue to be made to develop this resource. If extravagance is forbidden by Islam, it is even more applicable to water. Indeed, Islam emphasizes in its teaching that it is our duty to conserve it. We cannot stress too strongly the need to observe the conservation measures laid down by the government in this respect. The use of this vital resource throughout the world can have a great impact on future development strategies and indeed could become a decisive factor in political tension and thus world security.
His Majesty Sultan Qaboos Bin Said 18th November 1991
Foreword Dams, in the broadest sense, are major water projects that 6
contribute to development of water resources for use in different domestic, agricultural, and industrial usages in any country. Dams are engineering structures constructed on valleys, rivers, and depressions for the purpose of capturing and storing the maximum possible quantity of water. They are usually classified in terms of form, material and purpose. Since water resources are limited in Oman, the government has exerted great efforts in developing such resources through building recharge dams and small storage dams.
wadi reservoir dam water released for recharge
7
Aerial view of Al Khoud recharge dam during the 1997 flood
Groundwater Recharge Dams
bedrock aquifer
The concept of recharge
The main purpose of these dams is to enhance ground water aq-
alluvium downstream of the dam, after which it can be extracted
uifers through making use of flood water which is often lost to
for use.
the sea and desert. This can be done by storing such water under
The wise government has constructed 43 recharge dams during
the ground in order to use it later for various purposes. Moreo-
the periods (1985-2011) with a total storage capacity of more
ver. these dams provide some degree of protection against floods
than 95.401 million cubic meters all over Oman. These dams
as well as in curtailing intrusion of sea water into ground wa-
have captured about 1431.3 million cubic meters of flood wa-
ter aquifers. Recharge Dams are constructed on alluvial valley
ter from their commissioning to operation up to the end of the
channels for storing flood water in dam reservoirs for a tempo-
year 2011. The first recharge dam in the Sultanate is Al Khoud
rary period of not more than fourteen days to avoid evaporation
recharge dam which was constructed from December 1983 to
losses and health risks. Then the stored water is released slowly
March 1985. The length of the dam is 5100 m and the height is
through controllable culverts. to allow it to infiltrate into thick
11m with a storage capacity of 11.6 million cubic meters.
8
Wadi Dayqah Dam Wadi Dayqah Dam is one of the main wadies in the Sultanate and is located, 100 kilometers on the eastern mountains chain, south east of Muscat with a total catchment area of 2000 square kilometers. The catchment area is the total rainfall area forming many tributeries to later combine one major flow stream called wadi and usually the catchment is impounded by high mountains separated from other adjacent catchments.
Wadi Dayqah catchment is located among a number of Wilayates namely Wilayat Quriyat from the east, Wilayates of Bid Bid and Al Mudhabi from the west and Wilayat of Dama and Al Tayyin forms the majority of the catchment area. Wilayates of Al- Qabil, Wadi bani Khalid, Sur and Ibra are at the southern borders of the water catchment and wilayat Samail from the west and wilayat Al -Amerat at the northern border.
The catchment consists of 62 tributies and wadi Dama, wadi Al Tayyin and wadi Khabbah form the main tributeries of this wadi. Wadi Al Tayyin flows from the west side and meets with wadi Dama flowing from the south and flow to the east and joinning with wadi Khabbah flowing from
9
the south east to form the main stream of Wadi Dayqah which flows to the east south direction to end up in its final destination to the Gulf of Oman. The annual average flow of Wadi Dayqah
Dam Reservoir
at Al Mazara village (60) million cubic meter of which 10 million cubic meter of the annual average is utilized annually in agricultural purposes for the farms of Al Mazara, Hail Al- Ghaf and Dahgmer. The rest of the annual average flow goes in vain to the sea. Many studies were carried out to take advantage of this potentiality of the wadi by constructing a storage dam to achieve the maximum benefit of the water available. Hydrotechnical study carried out in 1993 was the most important one and recommended that the proposed site location at
Al Mazara is feasible and require further detailed study. In 2003 an economic and technical feasibility study was carried out and also prepared preliminary design of Wadi Dayqah Dam project and water supply to Muscat & Quriyat Project. This study proved that the dam will provide 35 million cubic meter per year of water with 95% reliability and Internal Rate of return of 12.2%, 10.381 million cubic meter of which will be utilized by the villages at the lower stream of the dam for
agricultural purposes. 3.99 million cubic meter will be used for domestic uses at Wilayat Quriyat and 20.629 million cubic
Dam Length
410m
Dam HeightÂ
75.43m
Dam Top width
5m
Dam Base width
55.4 m
Volume of RCC
590,000 m3
Design flood
18,398 m3/s
The main dam
Spillway lengthÂ
201.74 m
The main dam was constructed on the main flow stream of
Spillway height
67.5 m
Number of outlets
11
Outlets diameter
1 to 1.6 m
meter for domestic uses at Muscat. It is worth mentioning that through the wadi flow calculations, during the last few years, concluded that the dam lake will be able to secure water supply for three consecutive years during drought periods. The government has constructed Wadi Dayqah dam from 10
1/8/2006 till 31/10/2009 and the project consists of two dams; main dam constructed from Roller Compacted Concrete (RCC) and a saddle dam, the details are as follows:
Wadi Dayqah and it was constructed from Roller Compacted Concrete (RCC). The dam takes an arch shape with a vertical front at the side facing the reservoir. The dam also includes an-intake tower with 11 controlled pipes at various heights to control the discharged water at different levels. The following table shows the dam details:
The following table shows the saddle dam details:
Saddle dam
The saddle dam
Dam Length
360m
Dam Height
49.16m
Dam Top width
10m
Dam Base width
183m
Stones,earthfill/rock fill, filters and vertical wall
11
947,395 m3
This dam was constructed in the depression between two moun-
Reservoir
tains (the left side of the reservoir) to store water and prevent
The reservoir covers an area of (350) hectare when the dam is
it from flowing through this passage when the water raises in
full and extends to 6 km upstream, the reservoir perimeter is
the reservoir. The dam is constructed by compacted earth fill/
about (28) km.
rock fill and it has been provided with impermeable vertical
The reservoir storage capacity is about (100) million m3, which
cut-off wall and central core in the dam body. At the top of this
equals the average flow of the wadi for two years according to
dam there is an asphalted road extending to the main dam. The
the monitoring data of wadi flow. The annual evaporation aver-
road is about (0.6) m higher than the reservoir level when it is
age of the reservoir is (2.5) m, however it does not affect the
full.
volume of stored water.
and approximately 20 Km of pipelines were built. The first set of the second stage of the project was executed in 1996, which included four storage dams and three service reservoirs for water collection. In the period between 1999-2004, 12 storage dams were constructed in Jabal Shams villages, and in 2004, 3 storage dams were also constructed in Jabal A’ Surah, Wilayat of Ibri. 12
Storage Dams The purpose of building these dams is to provide and develop water resources for villagers and settlements spreading near wadi channels,. and mountainous areas which suffer from lack of water resources, and also to encourage human settlement in these areas. A study was carried out in 1989 regarding possible means to develop water resources in the Jabal AI Akhdar region as the population of such areas is increasing despite limited water resources. This study confirmed that the best way is to collect water in small storage dams. This idea was accepted by citizens due to its minimal adverse effects on current downstream users. The first stage of this project which serves twenty nine villages was completed in 1994. Twenty six small storage dams and three service reservoirs for water collection with ancillary works
In the same year (2004), the second phase of the dams and hydraulic structures project was implemented in Jabal A’ Surah, Wilayat of Ibri. This phase included the construction of 9 storage dams, three of them were in Al Jabal AL Akhdar, 4 dams in Jabal Shams, one dam in Jabal AL- Kawr and one dam in Wadi Amti. Another 4 storage dams were constructed in the same year in the mountainous areas of Dhofar Governorate. In 2007, two small storage dams were constructed in Jabal Shams and one dam in Jabal A’ Surah, and another 7 storage dams were constructed: one in each of Al-Jabal AL Abyadh in Wiylayat Dima & Al Tayeen, Jabal AL-Marrat and Jabal A’ Surah Wilayat of Ibri, two in Jabal Dhawi in Wilayat of AL Rustaq and two in Wilayat Ibri . At the end of 2011 another 20 storage dams were also constructed in AL- Jabal AL- Akhdar and one storage dam was constructed in Jabal Al Abyadh in Wilayat Dima & Al-Tayeen. The total number of storage dams in the Sultanate is 89 and estimated total storage capacity of these dams is about 231,191m3.
In the Sultanate, factors such as high steep mountains with dry climate and variable rainfalls lead to high peak flash floods that cause damage to life and property. In order to protect against such incidents, a number of flood protection dams were constructed. In Muscat Governorate 11 dams were constructed, namely, Muscat Dam, Al-Ansab Dam & Al-Jifnayn Dam. These are supervised and administrated by Muscat Municipality. The Ministry of Regional Municipalities and Water Resources has completed conSalalah Flood Protection Dam
Flood Protection dams
struction of Salalah Interceptor Guard Dam in Salalah, Dhofar Governorateand flood protection dam at Al – Amerat Heights. This is one of a series of flood protection dams (7nos) that will
Floods directly endanger human life and properties in differ-
be constructed in wadi Aday catchment. In addition to that,
ent countries and eras. Nevertheless agricultural areas are also
MRMWR has completed carrying out consultancy studies to
exposed to floods. A lot of dams in the world have been con-
construct flood protection dams in different wadis in Muscat
structed for flood protection and most of the multi-purpose
Governorate, Al – Batinah, Sharqia and Al-Dhakhilia. This is in
dams built do the role of flood protection.
order to protect against biggest floods of Gonu type.
13
Filter F Filter C 60,75
62,20
Rip Rap
Chimney Drain
Rip Rap
14 Filter C
Filter F 0
1
3
5
10 m
Dam components 1. Storage reservoir
2. Spillway
which the greatest possible quantity of water is collected.
it is designed to receive maximum flood water. The spillways of
Spillways are designed to be as large as possible to avoid erosion
groundwater recharge dams in the Sultanate should be of large
risks, and also to help in extending water to large areas down-
capacity as they are mostly located in the lower reaches of val-
stream the dam and accordingly increase groundwater recharge.
leys. Since they flow from large catchments of arid mountains,
in these areas.
flash floods produce extremely high flow which-peaks in these
It is one form of artificial reservoir on both sides of the dam in
It is that part of the dam which safely discharges flood water, and
conditions.
3. Stilling Basin
The main function of the stilling basin is to reduce the velocity of water overflowing the dam and to prevent erosion.
4. Dykes
These lie on both sides of a dam. Each dam has 15
left and right dykes and we usually find that the right dyke differs in length and height from the left one. The components or materials used in
in Dam’s Hydrological Monitoring System
constructing these dykes differ from one dam to another. Some are made of pure earth protected with rip rap, and others are built with gabion boxes and stones,
6. Monitoring Network
together with rip rap backfilling. Others are built with gabion
Groundwater recharge dams are provided with monitoring net-
boxes with stones and backfilling of each dyke with special earth
work consisting of stations for measuring rain water, surface wa-
and sand up to the rocky sides of the valley. Moreover, these
ter levels, water flow, aflaj flow, and groundwater level through
dykes contain sand filter to discharge infiltrated water and pro-
a number of monitoring wells. This is done for the purpose of
tect the dam, together with a concrete cutoff wall.
getting accurate hydrological and hydro geological information
5. Discharge Outlets
which could help to enrich knowledge about characteristics of aquifers, their capacity, and main relation between runoff and
These outlets are normally located on the spillway to release the
ground water recharging. Such information may be used to as-
stored water in the reservoir to the downstream area to allow
sess the effectiveness of dams and devise modern methods to
water to infiltrate into the aquifer. They are usually lined with
make necessary improvements to secure performance and safety
the normal wadi channels.
of these dams.
Dams and development of water resources 16
According to the monitored results of the operation of these dams, we can say, with thanks to God, they have not only achieved their intended purpose but some of them have realized greater dividends, as the dam value is recovered, in terms of water, in a very short period. Moreover, they have a number of positive impacts such as reducing saline water intrusion, increasing groundwater, and improving standard of living of mountain area residents in addition to preserving the stability of such communities. All citizens of this precious land should protect and safeguard all achievements of the blessed Renaissance. They should also participate in the development embarked upon by the Sultanate. In terms of dams, this should be through protecting their components especially measuring instruments which record data and information about water levels and wadi flow.
Groundwater Recharge Dams in the Sultanate No. Name Location
Capacity Year of (Mm3) Completion
No. Name Location
1 AL-Khawd
Seeb
11.6
1985
23
2
Hilti / Salahi
Sohar
0.55
1985
24 Bani Kharus
3
Quryat
Bahla
0.13
1986
25 A’Sarooj
4
Khasab
Khasab
16.00
1986
5 Shariya
Khasab
1.50
6 Mawa
Khasab
7 AL-Jizi 8 Tanuf 9
Ghul
10 AL-Kabir 11 Ma’awil 12 Fulayj (Sur)
Nakal
0.07
2004
Musannah
5.00
2004
Mudha
1.35
2004
26 A’Ssahtan dam1
Rustaq
0.04
2006
1986
27 A’Ssahtan dam2
Rustaq
0.07
2006
1.40
1986
28 Al Awabi
Al-Awabi
0.29
2006
Sohar
5.4
1989
29 Al Khab
Diba
2.80
2006
Nizwa
0.68
1989
30 Thumaid
BidBid
0.10
2006
AL-Hamra
0.45
1989
31 Al Guwaif
Biraimi
0.42
2006
Ibri
0.50
1990
32 Sahna
Madha
0.530
2010
Braka
10.00
1991
33 Wadi Al -Sarrin d/s Al-Amerat
1.070
2011
0.78
1991
34 Wadi Al -Sarrin u/s Al-Amerat
0.720
2011
Sur
Mistal 2
Capacity Year of (Mm3) Completion
13 Fara
Rustaq
0.60
1992
35 Wadi Musayiq
Mahdhah
1.750
2011
14 Fulayj (Halban)
Halban
3.70
1992
36 Wadi Mahdhah
Mahdhah
1.100
2011
15 AL-Taww
Barka
5.10
1992
37 Masah
Mahdhah
0.030
2011
16 Sahalnawt
Salalah
6.4
1993
38 Haywan
Mahdhah
0.012
2011
17 Ahin
Saham
6.80
1994
39 Abu Qala
Mahdhah
0.046
2011
18 Hawasinah
Kabura
3.70
1995
40 Naam
Al – Qabil
0.722
2011
19 AL-Ala (1)
Bahla
0.04
1996
41 A’Rasah
Al – Qabil
0.775
2011
20 Al Ruhbah
Bahla
0.05
1996
42 Uqaiidah
Al – Qabil
0.435
2011
21 AL-Muaydin
Nizwa
2.50
2002
43 Saih Al Berair
Sohar
0.02
2011
22
Nakal
0.18
2004
Mistal 1
17
Storage Dams in Sultanate of Oman Muscat Governorate No. Dam Location 1 Dayqah
Quriyat
Capacity (Mm3) 100
770
Height Year of the completion (m)
(Main dam + Saddle dam )
18
Length (m)
75.43
2009
Al Jabal Al Akhdar No. Dam
Capacity (m3)
Length (m)
Height (m)
Spillway Length (m)
Pipe Length (m)
1
Dar Al Hajimat Dar Al Atam
5000
53.2
7
30.8
990
2
Wadi Bani Habib
9000
26.3
9
20.7
220
3
Sayq
7000
44.75
7.5
29.15
890
4
Al Shurayjah
10200
46
6
42
1440
5
Al Ayn
3600
36
4.5
20.4
1120
6
Hayl Al Yaman
3800
28.65
8
23.6
350
7
Manakhir-1
8400
38.05
6.5
23.2
1840
8
Manakhir-2
6000
42.2
5.5
22.5
170
9
Salut
5500
23.08
5
19.1
710
10 Masirat Al Ruwajih
8750
94.4
5.5
38.1
150
11 Marwah
1050
26.6
14.75
590
12 Al Ru’us
1050
27.35
5.5
13.35
260
13 Qart Shamis
1500
26.5
5
13.4
300
14 Qayut
1300
29.5
7
22.4
350
15 Masirat Al Jawamid
1250
18.85
6
10.95
60
16 Hulaylat
1300
15.6
5
11.4
330
8
17 Hayl Al Hadab
2700
32.55
5
22.15
970
18 Mahbat
1000
15.3
5
15.3
140
19 Aqbat Al Bayut
840
19.9
7.5
13.45
310
20 Al Ghalil
1200
20.87
5
13.9
810
21 Salylah Al Maqul
1300
20.45
8
15.1
1370
22 Al Elaylinah
900
52.55
5
26.2
680
23 Al Gharir Al Sufalah
900
26.2
7
15.3
1610
24 Sharjat
850
27.15
4
11.6
130
25 Al Kuhuf
750
21.45
5
17.95
490
26 Kaf Al Ahmar
2200
34.75
5
19.2
840
27 Khudriaya
4500
25
5
23
500
28 Al Shurayjah
3150
50
8
40
1150
29 Juwail Al Nasl
350
22
5.5
14.5
300
30 Amti
240
31 Al Soograh
4000
25
32 Qatam (Al Widyah)
8000
33 Al Qanfoor (Downstream)
23.6
3
21
150
7.5
21
600
28
8.5
24
1500
4100
28
6
24
600
34 Al Qanfoor (Upstream)
1400
14
3
12
-
35 Al Duwakhla
6000
28
6
23
1000
36 Al Ayana
2000
5,27
8
24
400
37 Saqa
1000
23
7
20
450
38 Al Ketet
5000
32
7
26
950
39 Al Lthuib
500
17
6
14
100
40 Al Dubia
2000
8
7
5
-
19
Al Jabal Al Akhdar No. Dam
20
Capacity (m3)
Length (m)
Height (m)
Spillway Length (m)
Pipe Length (m)
41 Al Majaza
4000
5,17
7
14
100
42 Al Kashada
3000
22
7
19
-
43 Hafrat Al Gareeqa
200
20
4
17
-
44 Suloot Al Sufla
800
5,33
5
28
-
45 Al Khumaira Al Alya
3000
15
6
12
-
46 Al Khumaira Al Sufla
2000
20
6
15
-
47 Al Mudahf
3000
29
7,5
26
500
48 Al Gheeran
2000
32
6
29
500
49 Sahra
3000
38
8
35
500
50 Al-Sheef
2000
25
7
22
300
Spillway Length (m)
Pipe Length (m)
Jabal Al Kawr No. Dam
Capacity (m3)
Length (m)
Height (m)
51 Dhum
7000
44.3
8
41.45
200
52 Dar Al Quroun
900
16
4
14.6
200
53 Dar Al Qurnayen
700
18.6
4
18.6
200
54 Ras Al Wadi
700
20.2
4.2
17.7
600
55 Sant
1422
27.4
4
23
-
Jabal Shams No. Dam
Capacity (m3)
Length (m)
Height (m)
Spillway Length (m)
Pipe Length (m)
56 Al Ghuwail
573
17.5
4
17
-
57 Hail Al Req
9500
26
6.5
20
700
58 Hail Al Shibak
2000
22
7.5
16
-
59 A’Suwaiqat UP
525
47
4.5
12.3
-
60 A’Suwaiqat DW
535
46
4.7
12.1
-
61 Dar Al Qil
850
14
4.25
13.7
550
62 Dar Al Lathib
530
36
3.5
16.2
-
63 Tawi Al Aqbah
1800
30
7
18
-
64 Wadi Harma
1260
16.5
6
15
1350
65 Dar Al Mahatta
800
24.5
5
22.5
950
66 Hail Dan Al-Daqiqah
300
7.5
5
6.5
100
67 Hail Al khadra
550
24
4.5
22
-
68 Dar Al - Aqur
600
18
5
15
300
69 Dar Lawa
313
15
4
14
300
70 Makhta Jabir
1547
12
6
10
1800
71 Al Laysilo
175
17.6
6.5
16
500
72 Sebaib
1500
20
6
18
-
73 Yasib
1700
18
6
16
-
21
Jabal A΄Surah No. Dam
Capacity (m3)
Length (m)
Height (m)
Spillway Length (m)
Pipe Length (m)
74 Hail Al Jawari
535
14.5
4
10
-
75 Dar Al Gnooz
2000
16
4.5
12
-
76 Aqbat Al Mishbak
450
17
4.3
13
-
77 Aqbat Al Suqbah
880
14
5
12
-
78 Ghulail Adinah
4700
30
5
23
600
Spillway Length (m)
Pipe Length (m)
22
Jabal Dhofar No. Dam
Capacity (m3)
Length (m)
Height (m)
79 Anjalah
830
61
2.5
80 Baal Dhad
1080
44
5
16
81 Shakhoo
3000
32
5
26
-
82 Kizatkhif
1830
105
3.8
12
500
61
67
Jabal Dhawi No. Dam
Capacity (m3)
Length (m)
Height (m)
Spillway Length (m)
Pipe Length (m)
83 Al Dar
326
14.4
4
9
500
84 Al Duwairat
4000
22
5
17
500
Jabal Al-Marrat No. Dam 85 Al Higar
Capacity (m3)
Length (m)
Height (m)
Spillway Length (m)
Pipe Length (m)
5000
39
7
35
600
Ibri 86 Sudadib
5200
40
4
23
-
87 Al Basatin
5000
38
8
27
-
Jabal Al Abyadh 88 Hail Al Kufoof
3800
15.7
5
11.7
600
89 Hail Al Huraim
4000
30
9
25
1000
Flood Protection Dams in the Sultanate of Oman No. Dam Location 1 Salalah 2
Al Amerat(B15)
Salalah Al Amerat
Length (m)
Height (m)
Capacity Year of (Mm3) Completion
6121
23
77
2009
5800
23
22
2012
23
24
25