“….in terms of internal erosion potential of the foundation, Mosul Dam is the most dangerous dam in the world… If a small problem [at] Mosul Dam occurs, failure is likely.” U.S. Army Corps of Engineers, September 2006 Presentaion - Nadhir Al-Ansari Professor - Department of Civil, Environmental and Natural Resources Engineering Lulea University of Technology Key Facts The Mosul Dam provides critical irrigation, flood control, and hydropower to NW Iraq Leaks were discovered within months of operation U.S. Army study concludes that the dam is at a “high risk” of failure Projected loss of life from dam failure 500,000 (U.S. Embassy est. 1.47 million) Only permanent solution is to construct a second dam at estimated cost of $2 billion

1. Mosul Dam: The most
dangerous dam in the
world.
OVERVIEW
Nadhir Al-Ansari
Professor, Lulea University of Technology, Sweden
Member of the Iraqi Forum for Intellectuals and Academics

2. Tigris River
Mosul reservoir reservoir
Spillway
Mosul dam site
North Al-Jazeera pumping
station
Hydropower generation

3. Mosul Dam Scheme

4. Mosul dam project (1986)
Main spillway

5. Mosul Dam is one of the biggest water projects in
Iraq.
Purpose
•Flood control
•Irrigation of area (2500ha projected)directly from
Mosul Reservoir and 750000ha from dam releases at
middle and south Iraq.
•Hydropower generation(4 turbines with total
generating capacity of 750 MW) + 300 MW (Pump
storage and Reregulating Dam).

7. • The total volume of material for the embankment is
reported to be around 37.7 million m3
• The upstream and downstream embankment slopes
are inclined 2.5:1 (horizontal: vertical) below El. 330
m, which is the normal high operating pool level.
• Above El. 330 meters, both slopes are inclined at
1.73:1.

8. Total Storage Capacity 11.11km3
Live Storage 8.16km3
Dead Storage 2.95km3

9.  Geotechnical
• Site selection
• Foundation
Problems

10. Karstified limestone and gypsum in the foundations of the dam

12. Solution crack

14. Sinkhole under a concrete pavement

15. Soil failure in a village on left abutment

16. Upstream right abutment, open fissure resulting from
slab slide

17. Sinkholes and Dissolution Phenomena
In March 2002 a large
dissolution tunnel was
discovered in a gypsum/
anhydrite layer in the right
bank of the reservoir . The
height of the cave was 1.3
meters with a floor level of
315 compared to 330.
which was the maximum
operation water level

18. Seepage from left abutment (photos taken in 2003)
The situation was stable with continuing dissolution .
Discharge showed strong correlation with reservoir water
level

19. Sinkholes and Dissolution Phenomena
The existence of (Wadi
Dermalih) under ground
aquifer was established
during the construction of
the underground caverns and
tailrace tunnel of the PS
scheme . The excavation of
the caverns was only possible
after completing grout
shields and drainage tunnels
around them. This photo
shows the huge spring which
had erupted from a gypsum-
breccias layer during the
tailrace tunnel excavation . A
great amount of grouting was
done to plug this spring

20. The Reservoir
W. A - 380 Km2

21. Boat path

22. Mosul reservoir boundary at 300 m a.s.l
Areas of sedimentation

24. Why we are worried now?

25. 1.Continuous seepage: It seems that the seepage
is increasing in 2015 (USACE)

27. 2.Development of sinkholes downstream and
upstream the dam.

28. 3.One of the two bottom outlet gates in not
functioning since 2013.

29. 4.Indications of settlements (USACE and
Richard Coffman, University of Arkansas ).

30. Globesar: settlement rate 5-10 mm/year

31. 5.Expected flood.

32. Consequences

33. Mosul
Tikrit
Water Depth: 24 m
Time: 4 hr
Q: 405000m3
/sec
Water Depth: 4 m
Time: 38 hr
Q: 46000 m3
/sec
Water Depth: 15 m
Time: 22 hr
Q: 185000 m3
/sec

35. • Projected loss of life from dam failure 500,000 (U.S.
Embassy est. 1.47 million)
• Flood wave will destroy the infrastructure of the cities on both
banks of the River Tigris downstream the dam to Baghdad.

36. Solution
Grouting

37. Mosul
Tikrit
Badush dam