Fifty years of shallowing former sandand gravel pits in the Netherlands:
: from win-win opportunity to major headache

  • Wouter Klein Koerkamp

Student thesis: Master's Thesis


What around 2008 looked like a win-win situation for applying soil and sediment from dredging rivers grew to be a major headache file for Dutch governments. In the Netherlands, nearly 500 artificial lakes have been created for mining gravel and sand. Making these lakes shallow (shallowing) seemed a solution to both increase the ecological quality of deep lakes and find an affordable location for contaminated soil and sediment.
The Dutch government works on a new policy. This study aims to provide recommendations for new policies. This is executed by reconstructing the evolution of past and current policies. Coding assumptions in policy
documents led to the reconstruction of the assumptions behind policy between 1970 and 2023. At these times, the first policy was drafted, and the current policy ceased to exist and was replaced by the 2024 Environment Act. Expert workshops, Evolutionary Governance Theory and Multiple Streams Framework where used to explain how and why the governance path is shaped by dependencies and how policy issues reach the governmental agenda. To do so, the question was answered as to which factors affect the policy for handling dredged material and soil for shallowing quarry lakes in the Netherlands, which lessons can be learned, and how these can be translated into policy recommendations.
The first factor affecting policy development is the continuous influence by three policy streams targeted at finding locations for leftover dredged material, environmental protection, and the need for materials for agricultural/building or natural development purposes. The interplay between these streams shaped the
governance path, formulation and implementation of policy and legislation, and depositing practices.

The idea of beneficial use emerged as a compromise in the presence of pragmatic solution in the ongoing search, serving as an institutionalised solution that could be implemented through a window of opportunity,
where the three streams converged. However, the mutual gains of the economic and ecological objectives also resulted in unforeseen consequences. There were doubts about whether practices meet ‘the spirit of law’ because a ‘demand’ for dredged material and soil that is created when beneficial uses where conceived in increasing numbers of initiatives. Other examples include the increased import of foreign materials and impact on groundwater and surface water. In 2019, the thus far, the obvious win-win situation was negated by ecologists, and the file emerged increasingly into a headache file.

The government re-implemented past solutions based on permission to migrate the effects. Once adopted, policies and regulations are not easy to change; they create a path and, thus, work through. This study showed that the use of past solutions is easy because they often meet community values, are publicly
acceptable, and have access to resources, skilled staff, and government infrastructure. The question however is whether policy bases on a system with generic barriers, which we know blocks the system of dredging –
transport – depositing behind the Dutch water infrastructure, is a logical choice. The study shows that these easy adjustments are viable and lead to societal rest in the short term but eventually lead to a dead-end path in the long term. The discussion is whether a radical change in policy is needed to anticipate long-term challenges related to circularity and climate. In addition, the once-thought ending of active policy-making for dredged material appeared to be wrong, which forces actors within and around the government to scale up
knowledge on policy and technical aspects of large-scale application in surface water again.
Date of Award30 Aug 2023
Original languageEnglish
SupervisorRaoul Beunen (Examiner), Jean Hugé (Co-assessor) & A.J. Wijdeveld (Supervisor)

Master's Degree

  • Master Environmental Sciences

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