Oman Dam Safety, Oman

PÖYRY PROJECT SUMMARY
Project Description
Consulting services for the safety evaluation of existing
recharge dams
Sultanate of Oman
The Ministry of Regional
Municipalities, Environment and
Water Resources (MRMEWR)
required safety evaluations of seven
existing recharge dams built between
1985 and 1992 in the Sultanate of
Oman. The objective of the study was
to evaluate the condition of each of
the dams and to assess their compliance
with public safety requirements.
The Safety Evaluation of Existing
Dams (SEED) procedure was used to
determine the condition of each dam
with respect to its structural and
operating integrity. This procedure
identifies any existing or potential
safety deficiencies and confirms them
by analyzing existing or developed
data.
Any engineering and geological
deficiencies identified from the site
inspection and/or from other sources
are entered into a database and
classed according to their degree of
seriousness. The measures analysed
covered the full range of issues that
normally apply to dams and included,
typically, hydrology and sedimentation,
hydraulics, seismo-tectonic risk,
geological, geotechnical and
structural issues, as well as the
required monitoring and maintenance
works. The analyses were made using
state-of-the-art techniques and
methods available amongst all
relevant disciplines, and were carried
out in the following two phases:
Client
Ministry of Regional Municipalities,
Environment and Water Resources
(MRMEWR), Sultanate of Oman
Project
Evaluation of the present condition of
seven existing flood protection and
ground water recharge dams.
Services
� Detailed inspection of the dams to
determine their present condition
� Review and analysis of geology,
hydrology and hydraulic data
� Tendering of sub-contracts for in
situ and laboratory testing
� Supervision of site investigation
works and laboratory testing
� Structural (stability) analyses
� Definition of remedial works
� Cost-benefit analysis of proposed
remedial measures
Execution Period
2005 – 2007
Phase 1 (inspection and examination)
was a technical assessment based on
all available data from site inspections
and reports on the dams. If the results
of this phase were inconclusive, a
Phase 2 study (investigation and
analysis) was required. This was a
more detailed study and included the
special field investigations and
laboratory tests needed to establish
the necessary design parameters for
the more sophisticated analyses of
the dams and their related structures.

Depth [m]
Sultanate of Oman: consulting services for safety evaluation of existing recharge dams,
Key data
Name of dam
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
1.60
1.80
2.00
Gypsum vs. Depth
Gypsum content [%]
0 5 10 15 20 25 30
TR-1
5
2
TR-2
7
Type of
structure
5
2 D2
7
Completion
year
TR-2
8 8
Max. height
of dam
TR-1
8
TR-1
Total length
of dam
Max. storage
volume
Capacity of
spillway
Wadi Al Jizi Zoned embankment 1989 20.40 m 1'234 m 0.66 Mm 3 7'800 m 3 /s
Wadi Al Khoud Zoned embankment 1985 11.00 m 5'100 m 11.60 Mm 3 12'500 m 3 /s
Wadi Fulaij (H) Zoned embankment 1992 7.70 m 3'346 m 3.70 Mm 3 2'200 m 3 /s
Wadi Ghul Gabion cascade weir 1989 7.60 m 415 m 0.09 Mm 3 2'800 m 3 /s
Wadi Khasab Zoned embankment 1986 23.00 m 830 m 16.00 Mm 3 1'000 m 3 /s
Wadi Shariya Zoned embankment 1986 9.20 m 740 m 1.50 Mm 3 400 m 3 /s
Wadi Mawa Zoned embankment 1986 8.00 m 820 m 1.40 Mm 3 350 m 3 /s
Dams covered by study with main characteristics.
Seepage along downstream toe of the right wing embankment of
Wadi Fulaij (Halban) dam following heavy rain and impounding in
February 2006.
Evaluation of laboratory tests: distribution of gypsum with depth (the numbers
refer to the number of the trial pit or trench from which samples were obtained).
In situ investigation works at Wadi Fualij (Halban) dam; drilling in
reservoir area to locate possible seepage zones in gypsum.