TKI- Urban Water Buffer

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Project date

01/06/2016 - 31/12/2018


  • KWR Watercycle Institute
  • Wareco
  • Codema
  • Gemeente Rotterdam
  • Gemeente Rheden
  • Gemeente Den Haag
  • Hoogheemraadschap Delfland
  • HoogheemraadschapSchieland en Krimpenerwaard
  • Rioned
  • Evides Waterbedrijf

Underground storage and recovery of rainwater in urban areas

Urban areas are increasingly facing flooding due to intense rainfall, as well as water shortages resulting from longer periods of drought. The current solutions are based on discharge and external supply, which are often expensive and not sustainable. How can we retain rainwater in the subsurface of urban areas longer and more effectively? And can we then subsequently make use of this water? 

Field Factors is working together with different water managers, companies and institutes in the Urban Waterbuffer project (UWB), which investigates how can rainwater in the urban area can be held longer and more effectively in the subsoil and recovered for later use.Two pilots sill be implemented in Rotterdam and Rheden.

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Need for space
The space needed for water retention and infiltration in urban areas is limited. This results in conflicts with other uses of space or in the implementation of costly solutions. With the Urban Waterbuffer (UWB), rainwater in urban areas can be purified and retained for longer, without conflicting with other spatial functions. The UWB uses deeper aquifers to infiltrate, store and extract rainwater through wells. The purpose of the project is to explore whether this solution can make a significant positive contribution to preventing flooding and improving water supply in urban areas.

In the first phase of the TKI- UWB project, the location, the water balance, the preliminary design and the projected costs of actually installing a UWB system has been identified for four cases: Spangen-Rotterdam, hNI- Rotterdam, Rheden and The Hague. The results show that, particularly in the case of the targeted locations in Rotterdam and Rheden, a UWB could make a concrete contribution in the short term to the discharge of surplus rainwater and thus to flood prevention. The aspects requiring particular attention are the speed with which the peak precipitation loads can be infiltrated into the subsurface, and the pre-treatment of the rainwater with a view to preventing clogging.


Pilot case: Spangen, Rotterdam

The stored rainwater in Spangen, Rotterdam will be used as a source of high-grade freshwater to replenish a pond and to irrigate artificial turf fields at the Sparta Stadium. These applications would likely cover a large part of the annual costs related to the depreciation, maintenance and management of the pre-treatment, infiltration and recovery. 

Pilot case:  Rheden

In Rheden, no use of the infiltrated water is envisaged at this moment, but the potential benefits are related to the limited surface space required, and to the relief of the municipal sewerage system.


Currently the definitive design and the implementation of pilot systems in Rotterdam and Rheden is on going. The operation of the systems will be monitored within this project.


Urban Water Buffer in Spangen

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30.000 m2

Disconnected paved surface

15.000 m3

Use of rainwater

50 mm

Retention capacity

Saving drinking water

Spangen, a neighbourhood located in the west of Rotterdam, is vulnerable to pluvial flooding during heavy precipitation events due to a lack of retention capacity. At the other hand, the Sparta Stadium, located in the neighbourhood, uses a significant amount of water for the irrigation of the sport fields.

We are working together with the Municipality of Rotterdam, Waterboard Delfland, Evides Water Company, KWR Watercycle Institute and BE-de Lier, on a pilot project to implement underground rainwater storage and recovery.

The aim of the project is to collect, filter, and infiltrate rainwater in the underground to solve the need for retention capacity in the neighbourhood; and to use the stored water to provide the Sparta Stadium with a decentralised source for irrigation.

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Exploring the possibilities.

A feasibility study has been executed, to explore the possibilities to integrate the system in the surrounding and to define the technical criteria for the design of the system. The starting point of the study has been the accommodation and spatial integration of the different functions of the system, including pre-treatment, water storage, and installations, without conflicting with the existing spatial functions, such as routing, parking, and green. The goal has been to integrate the system in such a way that it contributes to the enhancement of the surrounding.

Adding green and spatial quality, while making Spangen water resilient.
— How might we create value


Defining the technical criteria, drafting the spatial implementation

Based on the spatial possibilities, a technical design of the system with the associated technical specifications has been executed.


In close collaboration with designers and urban managers of the Municipality of Rotterdam, a definitive design for the square around the Sparta Stadium is currently being executed, integrating the functions of the UWB system, while giving the neighbourhood a pleasant public space.



The implementation of the project is expected to be executed by the beginning of 2018.

CORE: Flood-proofing through rapid prototyping in Bangladesh


300 m2

Discharged paved surface

150 m3

Stored clean water

50 users


Securing freshwater in times of flood

CORE is a research project led by UNESCO-IHE Flood Resilience Group in collaboration with the Bangladesh University of engineering and Technology focusing on community-based innovation, development, and implementation of small-scale technical innovations that alleviate immediate flood-related nuisance in a town in Bangladesh. 

Field Factors will develop and demonstrate a circular biofiltration & drainage system to be implemented at the CORE’s experimental learning space in Bangladesh, providing a sustainable solution for effective drainage during extreme rainfall while helping users to cope with water shortage during dry seasons. The system will be designed adapted to the location specific hydrological, environmental, social and economic conditions of urban Bangladesh. 

We aim at: 

  • Delivering on the intrinsic needs and economic opportunities in the local urban context of Bangladesh.
  • Making use of local available materials and resources to build sustainable water infrastructure.
  • Stimulating local adoption, ownership and replication of our solution. 

The implementation of the project is expected to start in 2018.  


Understanding the users and their needs.

Through field trips and workshops with local stakeholders and end-users, we have gathered insights into the users' needs and the local context, which we have translated into the definition of an impact project. 


Currently, we are working on the analysis of a primary school as a project site. We will provide a solution for sustainable drainage during extreme rainfall, while ensuring access to freshwater in times of flooding. By embedding the system in the context of a primary school, it will serve as and educational tool about sustainable water management and flood protection of critical infrastructure. 

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NAIAD: Mainstreaming Nature Based Solutions



R&I in EU

22 partners



NBS to be applied

Business models

Project outputs

Operationalising the insurance value of ecosystems

NAIAD is a H2020 project which examines how the insurance value of ecosystems for water related risk mitigation can be deployed. This is executed by developing and testing concepts, financial instruments and applications on 9 case studies across Europe, within the framework of Nature Based Solutions (NBS). 

The aim is to propose NBS as technically sound and financially viable option for investors at local and regional level, and especially for the insurance sector.


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Identifying stakes, risks and nature based solutions.

Focusing on specific casestudies in Rotterdam, technical and regulatory frameworks for risk management and the role of insurance will be identified, seeking to the give insights into the feasibility of applying small-scale green infrastructure systems as a sustainable measure for urban water management. The description of stakes and relative risks s confirmed through the elaboration of relevant local stakeholders. 

Understanding the socio-economic value and effects on pluvial flooding and periods of drought.
— How might we upscale the implementation of green infrastuctures


NBS scenarios to reduce the risk of floods and drought.

Design scenarios of green infrastructure will be compared with traditional grey infrastuctures.



New business models on the insurance value of ecosystems.


Strategies for adopting NBS in risk management.