Project to secure Muscat Governorate against flooding
MUSCAT -- Europe's leading engineering consultant, Sogreah, has been awarded a contract to provide consultancy services linked to the development of a major flood management scheme that will secure key residential suburbs of Muscat Governorate against severe flooding. As part of its brief, Sogreah will study the feasibility of constructing a system of flood protection dams in the upper catchment of Wadi Samayil, one of the Oman's biggest wadis that cuts through the capital region en route to the sea. In addition to undertaking the detailed design of work on this flood protection system, the consultant will also advise the government on upgrading the recharge dam at Al Khoudh into a full-fledged flood protection dam.
The project is one of several large-scale flood protection schemes drawn up by the Ministry of Regional Municipalities and Water Resources in an effort to prevent severe flooding in flood-prone areas of Muscat Governorate, and the Batinah and Sharqiya regions. Parts of the capital and the Sharqiya region in particular were severely affected by flooding during the adverse weather conditions of June 2007.
According to officials, Sogreah will study the most economically advantageous engineering solution for protecting flood prone areas of Al Khoudh, Seeb and Maabelah from flooding. The consultant will identify suitable sites for the construction of flood protection structures in the entire Wadi Samayil catchment, including the development of one or more flood protection dams. The dams will be designed with a large reservoir capacity catering to a flood frequency of a 1-in 200-year event or more.
In designing the dam capacity, the consultant will be required to take into account the latest hydrological data gleaned from the recent unusual weather conditions in the Sultanate. Experts point out that 2 or more dams will be necessary in the upper catchment if inhabited areas downstream of Wadi Samayil are to be secured from possible flooding.
The comprehensive study will cover a huge catchment area, which includes the entire Wadi al Khoudh catchment (flood plain) starting from the mountains in the upper catchment in the Samayil, Fanja and Bid-bid to the downstream reaches in Al Khoudh and Seeb in Muscat Governorate. It also includes the area around Wadi al Khoudh dam located some 5 km upstream of the Muscat-Sohar highway from the Al Khoudh roundabout. The total catchment area of the entire Wadi Samayil stretch is about 1700 km2, while that of the existing Al Khoudh dam is 1635 km2. Furthermore, the Al Khoudh recharge dam will be considerably strengthened and expanded.
The height of the dam is proposed to be raised by a few metres to roughly double its reservoir capacity. Additionally, the dam's length will be increased from the present 5.1 km to more than 6.2 km. These improvements are designed not only to enhance the overall safety of the structure, but also to give the function of a full-fledged flood protection dam. Besides identifying the need for repairs to damage caused by last year's weather conditions, the consultant will also design an improved dyke complete with suitable discharge channels to ensure that any overflow will run off into the main wadi channel and not flood inhabited areas downstream.
Sogreah is a major European independent consulting and engineering group specialising in the fields of water, environment, energy and urban development. The company has 15 permanent overseas offices mainly in Europe, Asia, Africa and the Middle East. Its Oman office has currently studying initiatives in the fields of flood protection structures and groundwater recharging. Sogreah is also providing assistance to the Gulf Cooperation Council in studying the feasibility of establishing a GCC water grid.
By Conrad Prabhu
© Oman Daily Observer 2008
