Project Summary
With their ability to manage rainwater, coupled with improving biodiversity and mitigating the urban heat island effect, it’s easy to see why blue-green roofs are so valuable, particularly in the world’s more extreme climates.
EPG was appointed to design the multi-level blue-green roof design with passive irrigation for rainwater harvesting at the Bank of Oman Headquarters in Muscat. The design was developed to include IDF (intensity duration frequency) curves, managing a 100-year storm event to mitigate any flood risk on the site. The blue-green roof had a complex variety of vegetation which was carefully selected to be suitable for the climate.
As well as the blue-green roof, the project integrated design plans for the car park which was built upon a Permavoid podium to mimic natural water management, bringing SuDS into an urban environment. Weight restrictions for the car park were factored into the design for car loading, as a crane was required on the structure during the build, so the car park floor was essential to accommodate this.
Challenges
Delivering a robust design to manage extreme weather made this project complex. Not only rain, but sandstorms. When sand is mixed with rainwater, it creates a thick concrete texture, making construction of the design more challenging.
Solution
To manage the storms, access points were established which could be cleaned out and a rigorous maintenance schedule was implemented. The passive irrigation strategy also ensured that when the weather conditions was dry, the vegetation remained watered and healthy.
Results
The Bank of Oman Headquarters adopted EPG’s SuDS design which remains in place over eight years later*. Adapting to the extreme weather events in the region, the vegetation not only aesthetically improved the building, but improves biodiversity for the city centre. The blue-green roof influences a climate resilient environment by reducing carbon emissions and the urban heat island effect. Flood risk for the car park is mitigated through the permeable paving and the water quality is improved. A 12-month maintenance plan was provided following the build for the SuDS elements, ensuring the infrastructure continues to work smoothly and is a long-lasting feature for the building. *Project designed in 2017
