Innovative measures to mitigate risk

Arriyadh Stormwater Masterplan Review

Riyadh, Saudi Arabia

In 2010, the Riyadh Municipality commissioned local engineering consultants to assess the baseline stormwater infrastructure for the city of Riyadh, and to propose a masterplan to upgrade and extend the storm drainage network to serve the rapidly expanding city’s urban development.

In November 2013, at the same time as the masterplan was being finalised, the city experienced the heaviest rainfall in more than 25 years. This caused severe and devastating flooding, resulting in the loss of life and bringing the city to a standstill.

Challenge

While such tragic events are rare in this region, they highlighted the lack of infrastructure in place to cope with intense rainfall events. As a result, the Governor of Riyadh instructed the Arriyadh Development Authority (ADA) to undertake a comprehensive review of the emerging masterplan to ensure that it was appropriate and fit for purpose.

Of particular concern to the city authorities at that time was the potential flood risk to Riyadh’s new Metro system that was under design when the flood occured, with construction about to commence.

Solution

In early 2014 the ADA appointed BuroHappold Engineering to conduct a comprehensive and independent technical review of all aspects of the stormwater masterplan, and requested a detailed action plan with recommendations and solutions to deal with any potential shortcomings found.

We undertook a thorough review of hydrology using our extensive knowledge of the Riyadh area, including a comprehensive hydrological review of the Wadi Hanifah and Wadi Sulay catchments that receive both urban stormwater discharge, and runoff from the rural catchments beyond the city limits.

Value

Looking at how storm profiles develop specifically in Riyadh, rather than applying standard profiles for the whole of the Kingdom, is a significantly different approach to take and, together with HR Wallingford, we demonstrated with an appreciable evidence base that this was the most appropriate approach for this review.