Low groundwater levels have been a cause for concern in the Netherlands for some time now. The adverse consequences of this are often referred to as ‘groundwater flooding’. As well as, for example, the drying out of natural habitats and agricultural crops and increasing pressure on the drinking water supply, groundwater flooding can also lead to damage to foundations, buildings and infrastructure. This is caused by subsidence and/or pile rot.
For instance, the Dutch Association of Insurers states, based on research, that at least one million homes and other buildings in the Netherlands are at risk. Furthermore, the damage could run into tens of billions by 2050. The cause of groundwater overload in a particular area is usually not straightforward. In many cases, the groundwater level is influenced by multiple factors. These factors include, for example, water abstraction, water level management, drainage (such as from leaking sewers), surface sealing, and extreme drought.
A further complication is that the relative contribution of each factor to the local problem is usually unclear. This makes it difficult not only to pinpoint a single ‘culprit’, but also to work towards a targeted, structural solution to the problem.
This raises the question of how damage caused by groundwater flooding can be prevented or mitigated, and who is responsible for this. Often, the first measures considered are those aimed at tackling the consequences of groundwater flooding. These might include the use of techniques to prevent subsidence and repair foundations.
On the one hand, this offers scope for innovation and presents opportunities for the market. On the other hand, it is costly and therefore not affordable for everyone, nor is it a priority for all. In some cases, the costs of remedial measures can be recovered from water abstractors under the Water Act. However, the scope of this scheme is limited and, as mentioned, the damage is often not (solely) the result of water abstraction.
Since damage caused by prolonged low groundwater levels is generally not covered by insurers either, those seeking to recover costs are often reliant on liability claims. This involves high legal costs. Parties can easily become entangled in issues of causality and other legal complexities. This often results in them still being left to bear the costs themselves.
Apart from the question of whether this is socially desirable and whether, for example, a national fund should be set up to compensate for such restoration costs, one might wonder whether this form of ‘treating the symptoms’ is really the best solution. It is certainly not a structural solution to the wider groundwater problem.
One might therefore also consider structural measures to tackle the root causes. Apart from private initiatives, such as disconnecting downpipes and reducing the impermeability of gardens to encourage water infiltration into the soil, the government could, for example, permanently raise the groundwater level. This could also be achieved by permitting fewer (large-scale) abstractions, regulating abstractions more strictly, and taking tougher action against illegal abstractions. It is also possible to reduce hard surfacing in public spaces on a large scale or to prevent certain forms of water-dependent land use.
These solutions lie primarily within the remit of water management and spatial planning. In addition to substantial investment, they require a fundamental re-evaluation of land use and spatial planning at local and regional levels. Such measures may come at the expense of deeply entrenched existing interests. They may, in turn, lead to other forms of (flood) damage and disadvantage.
The necessary social and political support for such far-reaching measures is therefore by no means a given. Furthermore, the technical and legal-administrative feasibility of these measures has not yet been sufficiently assessed. It remains unclear what the cost to the taxpayer might be.
It is therefore clear that much more research is needed into possible solutions. Further research is also required into the social consequences and costs involved. Only then can a serious political and social debate take place. Subsequently, the foundations of Dutch society, which have been undermined by groundwater-related damage, can be sustainably restored.
By: Herman Kasper Gilissen
(Herman Kasper Gilissen is an Associate Professor at the Centre for Water, Oceans and Sustainability Law at Utrecht University.)