Sponge city principle in the Moldauhafen neighbourhood
On Hamburg's Grasbrook, a new district is taking shape across approximately 47 hectares of former industrial and logistics land. Directly opposite HafenCity, the municipal development company is developing two neighbourhoods that will ultimately provide around 3,000 homes and 16,000 jobs. The area is supplemented by 18 hectares of public open spaces, sports grounds and playgrounds, alongside a direct link to the city centre via the planned extension of underground line U4.
A central element of the infrastructure provision is rainwater management based on the sponge city principle. Instead of discharging precipitation directly into storm sewers, HafenCity Hamburg GmbH is installing extensive underground storage reservoirs with a combined capacity of 6.3 million litres. Dr Andreas Kleinau, Chief Executive of the development company, explained that this system harnesses precipitation as a direct resource for local vegetation whilst noticeably mitigating urban risks such as heat and heavy downpours.
The concept was formulated in partnership with municipal utility HAMBURG WASSER as part of the RISA programme. Martin Gerhardt, Technical Managing Director of HAMBURG WASSER, pointed out that rainwater management has been an integral part of the public realm from the very beginning. The system makes it largely possible to dispense with conventional road storm sewers, conserves drinking water resources and strengthens local climate resilience.
Infrastructure, energy and marketing schedule
Alongside water infrastructure, energy supply is a focal point of the plans. Under a concession awarded in October, at least 90 percent of the heating supply from the start of operations in 2031 will be covered by renewable sources and unavoidable industrial waste heat. In the subsequent phase, the share of renewable energy is set to rise progressively to 100 percent. The cooling supply will be powered entirely by renewable energy right from the outset.
- —Start of construction on the first storage facilities in October 2026, with completion scheduled for early 2027
- —Complete installation of the 6.3 million litre storage system expected by 2030
- —Launch of marketing for the first plots in the Moldauhafen neighbourhood in December 2026
- —Planned structural construction on the marketed plots starting from 2028
With the completion of the entire storage network expected by 2030 and the imminent start of the structural building phase from 2028, Grasbrook is taking shape as a forward-looking urban development project in a direct Hamburg waterfront location.
