Learning Implementation of the Kier Decision for the Haringvliet Sluices: an innovative approach in Dutch water management

Introduction

In 1970, the Haringvliet was closed off from the sea by the Haringvliet sluices. Since 2018, the sluices have been allowed to be set slightly ajar to let migratory fish pass, as laid down in the Kier Decision. HydroLogic supported Rijkswaterstaat in elaborating the Learning Implementation approach and guided the associated research programme, in order to arrive, in a risk-driven way, at a responsible new operating programme for the Haringvliet sluices.

Duration: 2017-2025
Clients and parties involved: Rijkswaterstaat, water boards, knowledge institutes
Partners: Svasek Hydraulics, GoswinITP, Infram
Keywords: Haringvliet sluices, Kier Decision, fresh-salt dynamics, salinisation, fish migration, water management Netherlands
Models & Tools: research plans, field trials and measurement campaigns, three-dimensional salt models, data analysis, expert interpretation

Background

Kier Decision

The closure of the Haringvliet in 1970 caused the salt water, the greatest tidal action, and also certain fish species to disappear from Dutch waters. The Kier Decision is intended to make fish migration possible again by also opening the sluices partially at high tide, within preconditions for flood safety, freshwater supply and shipping. However, the fresh-salt “behaviour” in the Haringvliet under different conditions still involves uncertainties at present. There was virtually no experience with it, which means important knowledge is still lacking, for example to be able to analyse possible scenarios in advance using models.

It was therefore not possible to determine a priori an operational programme that provides the required certainty with regard to the freshwater supply. For instance, it was expected that the salt water would move mainly through the deeper parts (for example the old tidal channels) of the Haringvliet. However, it was still unclear at which (river) discharge the position of the fresh-salt transition can be controlled under different conditions, especially in the deeper parts.

Method

Learning implementation

The Kier Decision fits the trend in Dutch water management of serving various interests (shipping, flood safety, freshwater supply, ecology, recreation) alongside each other as much as possible through smart, flexible and situational operational water management. In cooperation with Rijkswaterstaat, an expert team and a sounding board group, HydroLogic drew up the implementation plan to put learning implementation into practice. The aim of the implementation plan was to arrive quickly and carefully at a new operating programme.

Research opportunities

Important for this was making use of research opportunities, carrying out studies and analyses in parallel where possible, creating synergy between modelling and practical research, and a continuous focus on managing risks. HydroLogic then coordinated the research programme and carried out the associated analyses, in close cooperation with partners, managers and knowledge institutions. Results were fed back directly into practice and used to improve the operating protocol of the Haringvliet sluices.

The result

Future-proof

The programme has led to a thorough understanding of the fresh-salt dynamics in the Haringvliet under different conditions. This laid the groundwork for the new operational operating programme for the Haringvliet sluices. Among other things, it incorporates knowledge on how to anticipate smartly the (variable) chloride concentration on the sea side, and the risk of rapidly changing Rhine discharges. With the basis for the new operating programme, the expected effects on fish migration could also be calculated by ecologists, and ideas for optimisations were included in follow-up research.

What did the project deliver?

Insight into the fresh-salt dynamics when admitting salt water into the Haringvliet
The basis for the new operating programme of the Haringvliet sluices
Through which, in addition to flood safety and freshwater, ecological goals are also served via the Haringvliet sluices
Substantiated by measuring, modelling and expert knowledge

“With a period of developing knowledge on the job, we have worked in an innovative way towards an effective, widely supported and workable basis for the operational operating programme of the Haringvliet sluices.”

Meike Coonen | Senior advisor