The development of flood protection structures could strengthen Budapest's long-term security

The effects of climate change are becoming increasingly tangible across Europe, especially in cities located along major rivers. Due to the extremes of the Danube's water levels, more frequent and intense flood waves, and the growing vulnerability of urbanised areas, flood protection is no longer a development opportunity but a fundamental safety issue.

With the selection of the winning contractors, the complex development of the Pest–North flood protection lines in northern Budapest can continue with European Union support, according to TED.

Overview of the Pest–North flood protection project

We previously reported on the project announcement, and the recently published notice discusses the results. The client for the investment is the Budapest City Council, and the project will be implemented in two separate parts:

• At flood protection section 101 of Pest–É, the winning contractor is A-Híd Építő Zrt., while
• in the case of defence lines 37–38 of the Pest–É flood protection section, the Colas Alterra Zrt.

The total contract value awarded is approximately 6.1 billion Hungarian forints, and the construction period in both cases is 23 months.

What will happen at defence line 101?

Protective Line No. 101 surrounds the North Pest Wastewater Treatment Plant and its buffer zones. The total length of the protective line is approximately 1,630 metres, along which:

• approx. 840 metres of flood protection embankment,
• approx. 790 metres of watertight reinforced concrete retaining wall,
• and 1630 metres of maintenance road is being built, uniformly MÁSZ (i.e. the standard flood level) +1.30 metres level of protection.

These will be the tasks on defence line sections 37 and 38.

The other half of the project concerns sections 37 and 38 of the Pest–North flood protection system, which are closely linked and will be implemented in a densely built-up urban environment.

Section 37 connects to the end point of defence line 101 at Zsilip Street. From here, the defence line runs roughly parallel to one of the Danube's bays and an existing box culvert, then reaches Váci Road on the south side of the petrol station at 16 Váci Road. The total length of the section is approximately 500 metres.

Section 38 starts at the end of Section 37, i.e. on the south side of the petrol station at 16 Váci Road, and continues along Váci Road to the transformer station located at the planning boundary. The total length of this section is approximately 585 metres.

The task of Colas Alterra is the comprehensive design and implementation of flood protection works in both sections.

615 metres of watertight reinforced concrete retaining wall and 135 metres of slotted wall will be constructed.

As regards the main technical solutions and quantities, the original retaining wall on a 220-metre section of stage 37 has already been widened using reinforced concrete walls and slotted walls. As part of this investment, mobile flood protection wall system elements will be purchased and installed on this section to supplement the existing wall structure.

A new 115-metre-long reinforced concrete retaining wall will be built on section 38, together with the associated waterproof substructure, constructed to a uniform protection level of MÁSZ +1.30 metres.

Looking at the two sections together:

• A total of approximately 615 metres of watertight reinforced concrete retaining walls will be constructed, partly supplemented with mobile elements.,
• In addition, a watertight reinforced concrete partition wall will be constructed over a length of approximately 135 metres, which will provide the necessary level of protection with mobile elements built from ground level.