Sur to get flood protection dam

Report
from Government of Oman
Published on 01 Jul 2012 View Original

A major flood protection project will be constructed in Sur to prevent a repeat of the death and devastation caused by flood events of recent years, including the tropical storms of 2007 and 2010. Under plans drawn up by the Ministry of Regional Municipalities and Water Resources, the flood protection scheme will comprise of a number of components at the heart of which is a new dam that will be constructed across Wadi Rafsah.

The dam will be built immediately upstream of an existing recharge dam at Fulaij. Along with other components of the scheme, which includes a reservoir and saddle dam, the project will intercept flood waters originating from the southern wadis crisscrossing the plain extending southwest from the Sea of Oman to the Eastern Hajar Mountains. This mountainous region is dissected by steep sided canyons and drained by numerous wadis that join together and flow as Wadi Rafsah.

Rampaging floodwaters unleashed by adverse weather in 2007 swept through urban parts of Sur wilayat, destroying roads and other infrastructure, inundating farms, and leaving a number of people dead. Significant damage also occurred during a similar flood event in 2010.

The New Fulaij Dam, as it will be called, will cater to floods greater than the 10,000-year return period flood (RPF), which is the estimate of the interval of time between floods. Strategically located just upstream of the Sur urban area, it will serve as an inceptor in the event of heavy flooding along Wadi Rafsah. Furthermore, the dam will help establish a large reservoir with a storage capacity of around 20 million cubic metres at Full Supply Level. A number of major contractors are lining up to bid for the ministry’s contract to implement the Flood Protection Scheme.

The successful bidder will secure a contract to construct an embankment dam with an asphaltic concrete core or plastic concrete core, similar to the Interceptor Dam built recently in Salalah. It will run a total length of about 1.1 km, and rise to a maximum height of 22 metres from the natural ground level.

Also as part of the project, a saddle dam will be built south of the flooded area. This component of the scheme will run a total length of about 550 metres and boast a height of about eight metres above the ground level.

The project also calls for the training of a significant part of the 52.4 km-long wadi. A system of weirs, and spilling and non-spilling levees, will help protect the wadi bed, while the channel will be deepened by two metres and widened to 100 metres. Of the roughly 9.12 km of wadi channel that will be trained, around 2.37 km will have a protected wadi bed.

The Wadi Rafsah Flood Protection Scheme in Sur Wilayat is the third such project to be initiated by the government with a view to securing key urban areas around the Sultanate from severe flooding. The first such scheme is already operational in Salalah, while the first component of a major protection system in Wadi Adai (Al Amerat) was commissioned recently. Similar projects are also envisaged in Al Khoudh (Muscat Governorate), and in the North Batinah and North Sharqiyah Governorates.