Transcript Rainwater Harvesting in Oman

Sultanate of Oman
Ministry of Regional Municipalities & Water Resources
WATER RESOURCES
MANAGEMENT IN OMAN
Dr. Aisha M. Al-Qurashi
Surface water Expert
Directorate General of Water Resources Assessment
Geographical Location
• Oman is located at the
southeast tip of the Arabian
Peninsula lying on the Arabian
Sea and the Sea of Oman.
• Oman covers a total area of
approximately 309,500 km2.
• The coastline extends for 3,165
km in length.
• The land area is composed of
varying topographic features:
valleys and desert account for
82% of the land mass; mountain
ranges, 15%; and the coastal
plains, 3%.
Climate and Hydrology
The Climate in the Sultanate of Oman varies from region to
another and from one season to another but can be divided mainly
into two seasons, namely:
• Winter: It begins in November and last until April. Average
temperatures are mild and pleasant, ranging between (20 - 28 0C) in
Muscat Governorate and varies slightly in other regions. In this season
the country is affected by thermal cycles which cause rainfall in the
eastern parts of the Sultanate.
• Summer: it extends from May to October, and temperature average
ranges between (27 - 37 0C) in Muscat Governorate, varying slightly in
other regions. During this season, the tropical climate moves to the
north towards the Arabian Peninsula, and the southwest monsoon
affects the far south of the country and the south-east. Dhofar Region
can be regarded as the exception, as it has a strong monsoon climate
and receives warm winds from the Indian Ocean
Rainfall Distribution in Oman
Precipitation continued…
There are four major ecosystems causing rain in the Sultanate, which
can be summarized as follows:
• High air pressure caused by cold boundaries: It is common during winter
and early spring, where it leads to rain fairly constant in the northern parts of
the country, and scattered showers of rain in the central and south of the
country.
• Tropical cyclones from the Arabian Sea : The thick cyclones originate over
the Arabian Sea and reach the Sultanate in an average of five years in Dhofar
and ten years in Muscat, and lead to heavy rains on the southern and eastern
shores of the Sultanate during the months of May and December.
• Seasonal coastal currents: These currents are common during the period
from June to September, associated with surface currents over the Arabian
Sea, where these currents are dominated by the south-west current, and may
be mixed partly with air current coming from the Gulf of Aden. As a result, the
summer in the Governorate of Dhofar is characterized by high humidity, a
decrease in the level of evaporation and fog during the months of June and
July.
• Convectional Rainfall : This kind of rain is the result of the presence of local
convectional storms, which can occur at any time during the year.
Climate and Hydrology, Continued …
Evapotranspiration
• The high summer temperatures and low humidity in the interior
region allow high evaporation conditions.
• Daily evapotranspiration average exceeds 12 mm, while it drops in
the coastal areas of Al Batinah and Salalah to reach less than 10
mm per day, as a result of high humidity.
Available Water Resources
1. Conventional Water Resources (represents 84%) and can be
divided into :
• Surface water resources:
– Rainfall: the total average annual amount of rainfall is estimated
at about 9,481 Million m3. About 80% of this quantity (7,585
Million m3) is lost to evaporation.
– Wadi Flows: During floods significant quantities of water (1,422
Million m3) replenishes the shallow alluvial aquifer through direct
recharge along the coarse wadi gravel and the gradual release
of water from recharge dams. The remaining (474 Million m3) is
lost to the sea.
– Ghaili aflaj: which are based on the perennial flow in a wadi.
These type of aflaj represent 48% of the total number of aflaj in
the Sultanate.
– Springs: Most of these springs are located in the mountainous
areas. Springs on the northern side of the mountains discharge
hot water and are used for therapeutic purposes
Conventional Water Resources, continued…
•
Groundwater resources:
– Represents 94% of the available conventional water resources and
can provide about (1,295 Million m3 /year) of water.
– It is the most important source of available water in Oman and
usually used through dug wells and Daoudi aflaj.
– The geological characteristics of Oman regions play an important
role in forming groundwater resources; therefore it differs in quality
and quantity from a region to another.
– exists in renewable alluvial aquifers (unconfined and shallow)
recharged from infiltration of surface water flow along wadis.
– The non renewable groundwater resources are found in relatively
deep confined aquifers which receive little or no recharge.
Available water Resources
Use of Non-Conventional Water resources
It represents 6% and can be divided into :
•Desalination of Seawater and Brackish Water
•Wastewater Treatment and Reuse
•Treatment and Reuse of Oil Production Water
•Cloud seeding
Use of Non-Conventional Water resources
Water Use in Oman
During the last ten years, the Sultanate witnessed a great transformation
in water uses. Consumption of water for industrial, commercial, municipal
and tourism increased by 300% times than normal rate from (86 Million
m3) in 1998 to (399 Million m3) in 2007. The increase is attributed to the
growing economic activities in all sectors in that period. The agricultural
sector is the main consumer of water with a consumption of about 78%
followed by the domestic uses (12%), the commercial, industrial and
municipal uses (6%), the environmental uses (3%) and livestock (1%).
Water Deficit
Available data indicate that the quantities of consumed water exceeds the
available resources by about (378 Million m3) per year.
Water Resources Supply Management
These was carried out through:
– Water Resources Monitoring
– Water Resources Exploration and Assessment
– Water Resources Development
Water Supply Management
1- Water Resources Monitoring
Rain Stations
Region
Flo
dam
planet
w
s
s
peak
16
6
1
5
24
173
70
5
0
21
1
9
0
35
123
72
16
28
10
5
17
25
228
24
6
0
5
5
9
88
AlBuraimi
7
1
1
4
10
AlDhahira
11
0
1
9
AlDakhili
18
1
7
13
3
5
AlWusta
AlBatina
Wadi
Automatic
Salinity
Well
Afla
measurement
j
Springs
lagoon
Well
Wel
Fala
s
drainag
l
j
0
45
75
420
0
0
22
72
371
0
0
0
38
24
399
1
0
0
0
0
1
115
242
18
0
0
0
9
18
310
21
274
70
0
0
0
25
70
481
10
23
341
113
6
6
0
71
119
709
0
3
41
206
116
0
0
40
15
116
553
4
1
0
16
183
40
0
0
0
32
40
321
0
0
0
2
0
24
0
0
0
0
0
0
26
s
Sum
e
South
AlBatina
North
Musanda
m
a
AlShariya
North
AlSharqia
South
AlNajd
4
0
0
6
17
55
0
0
0
0
96
0
178
Salalah
6
0
1
18
15
170
0
37
11
139
353
48
798
Sum
135
26
31
79
236
2107
524
64
11
179
706
538
468
1
315
1289
Water Supply Management
2- Water Resources Exploration and Assessment
Water resources exploration and assessment programs have been
implemented in various areas and governorates of the Sultanate during
the past decades. These programs led to the discovery of a number of
groundwater aquifers which allowed the implementation of water supply
schemes, the most important of which are:
• Al Masarrat Project
• Ash'Sharqiah Project
• Wadi Al Maawil Project
• Project of Wadi Rawnab in Al Wusta Region
• Al Najd
Water Supply Management
3- Water Resources Development
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The Government of the Sultanate of Oman is exerting great efforts to develop water
resources in order to meet the increasing water demands resulting from the
successful, economical, industrial and social development the various fields. Several
programs related to water resources development have been implemented among
these:
•
Dams:
- Recharge Dams: The main purpose of these dams is to enhance groundwater
storage through getting use of valleys flood water which is often wasted in sea
and desert. The number of recharge dams that have been constructed during the
period from 1985-2001 are (39).
- Flood Protection Dams: There are (14) dams are being constructed in Muscat and
Musandam Governorate to protect occupants of downstream areas from flood risks
and can be used for recharge when ever possible.
•
Rainwater harvesting:
– Small retention dams
– Cisterns
– Quarry pits
Water Resources Development
Rainwater Harvesting in Jabal Al-Akhdar
In order to solve the problems related to water shortage, the Government
studied the implementation of several techniques, among them is the rain
water harvesting.
Jabal Al-Ahdar is one of the mountainous remote area that located in
Northern Oman. It is a unique area and known for its spectaculars scenery
and it comprises an important historical heritage and cultural treasures.
Even though, the mean annual rainfall is about 300 mm which is higher than
other parts in Oman, the areas suffers from natural water resources. The
rugged terrain with steep mountain slopes which can retain little rainfall water
and the bigger part infiltrates into rock fractures or it drains off directly to the
foothills where it reaches the aquifers of the adjoining plains.
Rainwater Harvesting in Jabal Al-Akhdar
Water Situation in Jabal Al-Akhdar
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Water is supplied by aflaj which are fed by springs or underground mother
wells
Currently, the water demand is rising due to the natural increase in
population and improvement of the standard of living, new wells with
additional water abstractions for non agricultural purposes that affected
the aflaj system, beside the rainfall pattern where the average rainfall has
decreased in the last few years.
Water shortage caused the abandonment of some farms and believed to
has some effects on the soil
The limitation of the existing water supply facilities is believed to have
some effects restricting population growth.
Shortage of water, which occurred occasionally, forced people to ration
their water provisions, to obtain water from distant sources, or migrate to
other villages or to abandon their settlements
Jabal Al-Akhdar
Rainwater Harvesting in Jabal Al-Akhdar
Different Studies on Possible Solutions
To support the locals in the mountainous areas and to provide a sufficient
basis that allows them to continue their traditional way of life with respect and
retain of the social structure of settlements, while profiting from modern
achievements, the government had made great efforts to study the best ways
and techniques. Hence, many studies were carried out in the area to study the
situation and possible solutions for solving water resources shortage
problems
The Main Studies that were carried out can be briefed below:
• In 1989 a reconnaissance survey and study of water resources in the Jabla
Akhdar was carried, “Development of Water Resources for Agricultural Use in
Jabal Akhdar”. The report identifies a number of ways in which the water
supply facilities of region could be improved.
• In 1990, a study was carried out,’ Jebal Akhdar, 64 Hydraulic Structures”.
The study aimed to evaluate the potential for improving the water supply
resources of a number of settlements, principally in the higher reaches of the
Jabal Akhdar, for which retention dams were listed as the preferred option.
Rainwater Harvesting in Jabal Al-Akhdar
Different Studies on Possible Solutions
In 1999, The Ministry carried out s Feasibility Study for Flood water
Harvesting Techniques in Oman to:
– Identify, study, evaluate, rank, and recommend suitable sites of disused quarry
pits as recharge pits and sites for other flood water harvesting techniques
suitable in Oman. Eight water assessment regions were comprised
– Spate irrigation system were also studied
– Injection wells, recharge shafts were also suggested with recommendation of
further studies
– Economic analysis, Socio-economic and environmental aspects, operation and
maintenance aspects, and ranking and prioritization of quarry pits, were all
considered in this study
The study concluded that 11 quarry out of the 45 that were studied were
considered as viable recharge pits (infiltration ponds) in Oman
Rainwater Harvesting in Jabal Al-Akhdar
Possible Solutions
The survey and studies indicated that the most efficient way for water
augmentation is the construction of retention dams for the following reasons:
– Artificial recharge is not feasible in the higher reaches of Al-Jabal Al-Akhdar due
to the non existence of suitable aquifer
– Natural groundwater storage and transport occurs mainly in rock fractures and
this source of already used by the traditional water supply systems such as aflaj
– Only retention dams were found to be not affecting adversely the existing water
supply systems
– It is a traditional and well known method in Jabal Al-Akhdar and therefore, fully
accepted by the villagers without unwanted social impacts on the communities
– Agricultural villages can use the natural stored water for irrigation through aflaj
system and the stored water by the retention dams for domestic use, livestock,
and expanding agriculture activities
– The stored surface water allows for preserving the high quality spring water for
drinking purposes only which will help in counteract the trend of increasing well
abstraction
Rainwater Harvesting in Jabal Al-Akhdar
Construction of Small Storage Dams
As a results of the above mentioned water resources situation in Jabal AlAkhdar, fifty small storage dams were constructed in Al Jabal Al-Akhdar to
provide and develop water resources of village occupants and population
spread near wadi channels, and remote mountain areas which suffer from lack
of water resources.
• The project comprised the storage dams, pipelines to the villages and farms,
and small service reservoirs or water tanks
• Local material were used when ever is possible, using donkeys to transport
them to the site, otherwise helicopters were used to transport the material as
only few sites have been accessible by vehicles.
Rainwater Harvesting in Jabal Al-Akhdar
Small Storage Dams
Rainwater Harvesting in Jabal Al-Akhdar
Small Storage Dams
Rainwater Harvesting in other Remote Areas
• The success of the construction of small dams in Jabal Al-Akhdar let
to construct similar small surface storage dams in different areas of
the Sultanate to provide water for agricultural and livestock use.
• A total of 90 small dams were constructed in Oman with a total
capacity of (137.9) Million m3;
– 6 dams in Jabal Kor
– 5 dams in Jabla Surat
– 4 in Dhofar Governorate
– 2 in Jabal Al-Abyadh
– 3 in the mountainous areas in Ibri
– 3 in Rustaq
Other Storage Dams
Wadi Dayqah Dam : The largest concrete storage dam in the Arabian
peninsula. The maximum storage capacity of this dam is 100 Million m3. The
expected yearly yield is in the order of 35 Million m3 to augment priority
domestic supply in the Capital Area (20 Million m3/year) and to provide the
Wilayat of Qurayat with both domestic and irrigation water supplies (15 Million
m3 /year).
Other Rainwater Harvesting Techniques
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Birkats or Cisterns: it is a traditional system of water harvesting that is
designed to collect and store rainfall – generated flows.
It comprises an excavated chamber or naturally occurring hallow structure.
For centuries the utilization of birkats has been vital for the survivals and
development of many remote settlements in the Musandam peninsula
where they serve as the only source of water to meet domestic and
livestock requirements.
The government decided to maintain the cisterns as they are important in
enhancing the water resources in Musandam.
An inventory of these cisterns was undertaken in Musandam Governorate
with a view to establishing location, assessing structure status and water
use, and determining maintenance requirements together with estimated
cost. A total of 967 cisterns were located, where 80% were found
operational.
The Government decided to aid in maintaining theses cisterns through
providing the required materials to the owners of these cisterns
About 147 cisterns were maintained in Bukha, 225 in Daba, and 595 in
Khasab, were maintained in the last few years.
Other Rainwater Harvesting Techniques
Birkats or Cisterns
Water Demand Management
Water-demand management consists of all activities to increase efficiency in
water supply and water usage and promote water recycling.
• Incentives will be given to agricultural activities using modern irrigation
systems, industries that practice water reuse since they contribute directly to
water-demand management and to the reduction of effluents.
• New housing, commercial and industrial estates shall be fitted with watersaving devices, including rainwater harvesting devices.
In order to insure the success of water demand management strategy in Oman
three major projects aiming at the evaluation of water use and the development
of water resources database in Oman were undertaken. These are:
• The national well inventory project:
• The Aflaj inventory project:
• The hydrogeological maps project:
The Way Foreword in Water Resources
Management
The main issues to achieve these principles are:
• Balancing water uses to water availability
• Adopting improved irrigation techniques and selecting appropriate crops to
reduce agricultural water use
• Managing water resources effectively and efficiently
• Increasing the use of treated wastewater and desalinated water
• Minimizing water pollution, flood damages and drought consequences
• Provision of sufficient water to spur and sustain economic
• Provision of access to safe, adequate and affordable water supply, hygiene
and sanitation
• Protecting the groundwater resources in qualitative and quantitative terms
• Creating and cultivating conservation awareness;
• Establishing an integrated program for the conservation and management of
the resources at basin level
• Controlling saline intrusion by reducing abstraction below the long-term
recharge
• Controlling urban water losses
• Using Rainwater harvesting techqniques for remote areas when ever possible
Thank You