Ruimte voor water - Centraal Holland

In response to rising pressures from climate change, FABRICations' "Room for Water" project in Centraal Holland identifies transformative strategies for water resilience, particularly to cope with increasing water nuisance and longer periods of freshwater scarcity. This research identifies measures to adapt to these situations in the future and bridges the technical implications with spatial planning.

  • Location
    Centraal Holland (Deltaprogramma), Netherlands

    Year
    2024

  • Rijkswaterstaat
    Provincie Utrecht
    Waterschap Amstel, Gooi en Vecht

  • Provincie Noord-Holland
    Hoogheemraadschap van Rijnland
    Hoogheemraadschap Hollands Noorderkwartier
    Hoogheemraadschap de Stichtse Rijnlanden

  • Project leader
    Rens Wijnakker

    Team members
    Mark Slierings
    Duong Bui
    Arina Novikova
    Samuel van Engelshoven
    Georgia Kokolaki

Together with Rijkswaterstaat, four water boards and two provinces we worked on a comprehensive "quick-scan" analysis, mapping out spatial demands and prerequisites for enhanced water management over three scale levels:

  • Polder system: low lying fields were rain falls and needs to be pumped out from or where there is a need for freshwater.

  • “Boezem” (in English: atrial) system: as intermediary of the system this network has a transport function and a low range of accepted fluctuation.

  • Main water system: In Centraal Holland the main water system consists of the river Lek, Amsterdam Rijnkanaal and Noordzeekanaal up until and including the IJmuiden Sluice and Pumping Station Complex. This system also allows only a narrow range of fluctuations, which can quickly impact functions such as shipping.

In general, there are three principals for a future-proof water system, in order to be resilient in the future all of these options should materialize:

o   Adapting the Water System: by increasing the pump capacity of the boezem- and main water system, reducing salt water intrusion and increasing the capacity of water inlets.

o   Making the System More Robust: by creating spaces for temporal water storage, conservation zones for freshwater (in the context of Centraal Holland this requires a very big implementation for it to be effective) and sponge city measures.

o   Adapting Land Use: through accepting more water (eg. extensive agriculture or nature development), reducing demand for freshwater (eg. by optimizing groundwater flows).

Water Nuisance

Water nuisance can arise in various ways, including (heavy) rainfall or technical failures (such as a pumping station outage). This can lead to nuisance at different scales. To minimize this as much as possible, several measures can be implemented. We identified three main measures to limit (damage from) water nuisance.

  • Establishing retention areas to locally mitigate damage within the polder system.

  • Creating retention areas that relieve pressure on the boezem system (managed by the water boards) or the main water system (managed by Rijkswaterstaat).

  • Increasing pump capacity to external waters.

While local water retention areas in Centraal Holland are vital yet space-demanding, they can integrate with other land uses such as nature, recreation, and housing. Retention areas linked to the boezem and main water systems have a limited amount of possible locations while posing uncertainties regarding capacity needs. This highlights the need for a comprehensive approach, where targets for the level of robustness need to be set and - in return - met through regional planning.

2_Measures water retention in polder system.png
3_Measures water retention in boezem and main water system.png

Freshwater scarcity

During dry summers, freshwater shortages can emerge. In these cases the amount of water that is let in from the Lek and Markermeer is insufficient to lower the salinity levels that are entering the main water system through the lock complex at IJmuiden. In this case fragile functions and soils like nature (in case of irreversible damage), peat (oxidation), stability of water barriers, energy and drinking water facilities are prioritized over shipping, which can result in the temporal closing of the lock complex. This illustrates that the issue is not simply a lack of freshwater; instead, it hinges on the choices we make between economic activities, like shipping, and land use functions.

  • Spatial measures to combat local freshwater shortages are mostly still under research. This quick scan includes the following measures:

  • Demand reduction through adjusted water management and spatial adaptation

  • Limiting water loss through limiting drainage and better use of seepage flows.

  • Retaining local water in specific situations.

Our quick scan indicates the pressing need for clear objectives in managing freshwater shortages, particularly as climate change increases demand while reducing supply in Central Holland. Without specific long-term goals, investment direction remains uncertain, complicating our response to these challenges. While large-scale water conservation poses practical challenges, simpler demand reduction measures can provide immediate local benefits, although their full impact is still being studied. Additionally, the relationship between water availability and quality needs more attention, as reduced water availability complicates compliance with regulations. Effectively addressing freshwater shortages requires a strategic approach that balances competing needs and acknowledges the complex interplay between water management objectives.

4_Measures freshwater scarcity demand reduction through adaptive watermanagement and spatial adaptation.png
5_Measures freshwater scarcity limiting water loss through limiting drainage and better use of seepage.png
6_Measures freshwater scarcity retaining local water in specific situations.png

Spatial demand

Dealing with excess or scarcity has significant spatial implications across various regions. Certain areas stand out due to either high uncertainty yet potentially large spatial impacts, like those involving pumping stations or main water system storage areas, or due to layered challenges where solutions are difficult to combine, such as balancing storage with conservation. Our hotspot map highlights regions where water challenges overlap or where spatial impact could be substantial. This map focuses exclusively on water-related issues, providing a clear view without consideration of other spatial developments, like urban expansion. Next steps will comprise of better understanding specific spatial conditions for these measures as well as synergy opportunities for multiple forms of land-use.

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