Geological and Geotechnical Study of Badush Dam, Iraq

Badush Dam is a combined earthfill and concrete buttress dam; uncompleted, it is planned to be a protection dam downstream of Mosul Dam, which impounds the Tigris River. Mosul Dam is also an earthfill dam; it is the largest dam in Iraq. The safety of Mosul Dam is a matter of debate since its commissioning in 1986. This is attributed to the geological conditions at the dam site are not suitable due to thick exposures of karstified gypsum rocks, which extend, deep down, into the foundations. Therefore, Badush Dam was planned and designed to protect the population and present infrastructures downstream of Mosul Dam, if the latter would collapse. The geological conditions at Badush Dam site are similar to those at Mosul Dam site, which means; the foundations of the dam, are located on karstified gypsum beds also. Grouting works were planned and designed, and they were partly performed simultaneously with the beginning of the construction of Badush Dam in 1988 and continued until the suspension of the construction in 1991. The constructed parts attained about (30 – 40)% of the work items. The design of the Badush Dam indicates clearly the temporary nature of its use, which is reflected in the thin inclined clay core and other embankment details. The basic design considerations of the dam were to have a dam, which is high enough to contain the full volume of Mosul Dam wave of 10 X 109 m3 when routed through its reservoir, and to limit at the same time the released discharge within the capacity across the downstream reach of the river without causing flooding. In this study, we have presented and discussed the geological and engineering geological conditions; whether Badush Dam can function as a protection dam or can it be remodeled to become a normal storage dam to replace Mosul Dam