The deepwater drainage tunnel built to help Dubai tackle stormwater issues has reached the pre-operational stage. AVK Gulf and Orbinox delivered the valve solution for the terminal pumping station that supports sustainable processes as well as the marine environment in the area.
Storms, heavy rain and flooding has previously caused damage and disruption in the area. In the hope of mitigating the effects, an extensive drainage solution was initiated. Exhibited as one of the most important exceptional infrastructure projects in Dubai, the stormwater system will serve the whole of Dubai South. The system will collect stormwater and surface water from a total area of 500 km2 – equivalent to around 40% of the entire urban city – transporting water through a 10.3 km long deep tunnel with an internal diameter of 10 m and a depth of 40-60 m.
The tunnel ends at the terminal pumping station near Jebel Ali Port, where water is drained through a double system, which can drain excess water through pumps connected to lines extending 600 m into the sea with high operational efficiency. This makes the main pumping station highly integrated when it comes to services, buildings, and facilities in the management of stormwater and surface water drainage. Offering protection to the marine environment, the collected stormwater will be discharged into the sea only after climate change and sea level has been considered, therefore, supporting the principles of sustainability and taking into account the safety of the marine environment.
One of UEA’s sustainability projects.The scope of work included the construction of a 30 m3/s and 55 mWC pumping station, auxiliary buildings and associated facilities.
Stantec was appointed as consultants, and the main contract to execute the job was awarded to Archirodon back in 2017. Archirodon was responsible to design and construct the terminal pump station. The station measures 150 x 175 x 62.5 (depth) m, and has an overflow structure with shoreline outfall, with 3 x 500 m HDPE pipes, 2,000 mm diameter outfall pipes, hydraulically actuated penstocks and valves, HVAC installation, power supply distribution network, power transformers and switchgears, as well as all associated buildings, including mechanical, electrical, instrumentation and control works and external works.
Finding the right valve solution
After Archirodon was awarded the job, they proposed three different designs to the client, Dubai Municipality, to meet the project requirements. AVK & Orbinox stayed in close contact with Archirodon from the early stages, and were therefore able to bring their expertise within especially engineered big valve solutions to influence the design proposal. As the specifications for the valve were not clearly defined, and even though the initial requirement was of a metal seated gate valve with hydraulic actuator, team from AVK Gulf and Orbinox focused on an Orbinox knife gate (DN2200) as the preferred suggestion. The gates were to withstand several challenges due to the collection of highly corrosive groundwater under high-pressure (PN 10), making the knife gate made of super duplex (SA2507) material with hydraulic actuator stood out as the ideal solution. After several meetings and visits, the knife gate solution was finally proposed as the most convenient solution for the client.
In September 2019, the job was awarded to AVK & Orbinox, not only beating tough competition from other European providers but also considering that a DN2200 metal seated gate valve that can be hydraulically operated is actually very difficult to find. Moreover, Orbinox’ WS model is a cost-effective solution with a proven track record of delivering similar solutions for various dams and reservoirs around the globe.
Due to the size, weight, and dimensions of these huge, heavy valves, installation at the site came with its own set of challenges – not eased by the fact that they were to be installed at a depth of 42 m below ground.The entire process was slow and labour-intensive, enabling accurate and precise installation at the very first attempt for every valve, which each came with a weight of 20 tones. However, the actual fixing of the valves to the pipes was relatively straightforward as they are fixed with bolts.
The hydraulic cylinders operating the valves were also installed with extreme precision and accuracy enabling them to operate smoothly. Close teamwork, engineering expertise and local support have proved to be our strengths throughout the project, securing a total project value of EUR 3.4 Million, opening an entryway into Dubai Municipalities’ robust project pipeline.
- 4 x hydraulic-operated knife gate valves, PN10 (DN2200)
The deep tunnel stormwater system is considered the first of its kind in the region to drain stormwater and surface groundwater, by collecting water and storing it for the next 100 years.