Wadi Dayqah dams

Supply drinking water to the cities of Muscat and Quriyat – that was the objective of this project entrusted to VINCI Construction Grands Projets by the Government of the Sultanate of Oman, which called for the construction of dams on the Wadi Dayqah some 80 kilometres from the capital city of Oman. The project included construction of a roller-compacted concrete main dam 572,000 cubic metres in volume, 75 metres high, and 435 metres long as well as an ancillary, earth-fill dam 960,000 cubic metres in volume, 48 metres high, and 360 metres long.

BACKGROUND

In this arid country with little precipitation (it rains rarely more one or two weeks a year), the total water supply for the population is below the recommended values set by the World Health Organization. Water supply is critical to ensuring public health and the country’s development.
That is why we were mandated to build main and ancillary dams to retain and store water from the Wadi Dayqah and supply it for irrigation and domestic use. Today, these structures supply around 100 million cubic metres of water to the people of Muscat.

TECHNICAL OVERVIEW

The project consisted in building two upstream gauging stations and an ancillary earth-fill spillway, conducting underground works to create the drilling and injection gallery and diversion works including maintaining the flow of the Aflaj (an irrigation water-course), building permanent access roads, installing electrical equipment, including cables, switches, and distribution channels, and putting the whole system into operation.
The soil on which the main dam sits is limestone with karst features. The ancillary dam is made up of sandstone and clay.
The main dam reaches a maximum height of 75 metres and was built with roller-compacted concrete; its total approximate volume is 570,000 cubic metres. The ancillary dam is an earth-fill structure that measures 48 metres in height and 960,000 cubic metres in volume.
To limit waste production, we implemented two measures: (1) we recycled materials; and (2) we raised awareness among our workforce of the need to manage waste at the worksite and base camp.
Waste was sorted on site and sent on for reuse. As a result, wood was used by local residents as kindling and steel was collected and sold locally for the purpose of recycling.

The shortage of water in certain regions of the world is a leading 21st-century challenge. This infrastructure was designed to address this challenge by supplying 100 million cubic metres of water in the desert.

IMPACT

As one of the largest dams in Oman, this structure located in the southernmost part of the Arabian peninsula, is designed to support the country’s economic growth.
The Wadi Dayqah dams provide drinking water to the cities of Muscat (the capital of the Sultanate of Oman) and Quriyat.
The human needs for hygiene, irrigation, and personal consumption are basic necessities. This infrastructure contributes to the country’s public-health objectives and its human and economic development.

Project participants

Client
Government of the Sultanate of Oman

Project management
Black & Veatch, Nespak, Suyapi

Key figures

Implementation dates
August 2006 to March 2010

Concrete
636,750 m3

Reinforcement
1,810 t

Excavation
1,016 million m3