Awa Spi Earth-Fill Dam Project
Qaradagh, Kurdistan, Northern Iraq
Total Excavation: 1,200,000 m3
Total Filler Material: 640,000 m3
Total Dumped Concrete: 95,000 m3
Project Budget: 18,500,000 USD
Developer: Ministry of Water Resources – Iraq Kurdistan Region
Project Manager: PM Global Project Management Inc.
Contractor: Maksomer Construction Inc.
Consultant: General Directorate of Dams & Water Resources
Construction Period: 2011-2014
Awa Spi Dam is on the Awa Spi valley / Qaradagh district which is at 44 km North of Kifri town, and at 61 km South West of Chamchmal District. The catchment area of the earth-fill dam is equal to 872 km2. The dam reservoir area is about (2.23 km2) at elevation level 472 masl (meters above sea level) which is the elevation of spillway crest level and this elevation gives live storage equal to 19,500,000 m3. The above figures show that there are four valleys discharging their flow into the dam reservoir.
The general purpose for developing Awa Spi dam is to control and store water to be used in irrigation of about 2400 acres of agricultural area and to supply water for population living around this district and livestock at Awa Spi area, and improve the environment condition of the region around the reservoir and the tourism in the region.
The main function of this structure is diverting water from upstream to downstream to keep the construction site dry. The main dam can be classified as a moderate height clay core-shell filter earth-fill dam (Height about 27m) with a coffer-dam. The construction period is three years.
The main structures of the dam
The dam embankments are earth fill consisted of clay core with shell material, filter and toe drain.
The dam structure consists of two reinforced concrete box culver of inner dimensions equal to (4×4) m at the inlet bed invert level of 453 masl for the diversion structure which is controlled by a coffer dam of crest level equal to 462 masl. This structure is designed on 3 years return period peak discharge according to flood discharge calculations in hydrology study which is equal to (274 m3/sec).
Concrete Weir Vertical Drop Type Spillway
Also, the dam structure includes impact basin which will be used at downstream of the dam to reduce the velocity and to dissipate the energy of the flow. Thus, uncontrolled free flow weir with 150 m waterway and crest level at 475 masl, maximum water level during flood reaches 478 masl for spillway location.
Bottom Outlet Design
Using 0.6 m diameter pipe for the bottom outlet to draw water from the reservoir for water demand, the pipe must be extended to dead storage elevation (463m).