Stage: Water Quality and Flushing Requirements of Lake IJsselmeer

How much water is needed to keep a freshwater lake healthy and maintain good water quality in a changing climate? During this internship, you will investigate flushing requirements of large freshwater lakes and explore what they mean for the future management of Lake IJsselmeer, one of the Netherlands' most important freshwater reservoirs. Your research will contribute to long-term decisions about water availability, water quality and investments in water infrastructure. Interested in combining scientific research with real-world water management challenges? Keep reading to learn more.

Please note: This is a research internship with a strong focus on literature review and analysis. The internship runs for approximately three months, from May to August 2027, and combines scientific research with its practical application to water management at Rijkswaterstaat .

Background

Climate change will increase evaporation rates, increase the length of dry periods, and raise freshwater demand for agriculture, drinking water supply, industry, and nature conservation in the Netherlands.

As a result, less freshwater may remain available for flushing Lake IJsselmeer as well as the Wadden Sea. Major investments are planned over the coming decades in discharge capacity at the Afsluitdijk (pumps and discharge sluices) to maintain the required water levels (safety, water availability and water quality). To support long-term decision making, a better understanding is needed of the minimum flushing requirements of Lake IJsselmeer and the associated operational conditions for the future water system.

Objective

This study will identify reported flushing requirements for large freshwater lakes and estuarine systems, with a primary focus on freshwater lakes, and assess their relevance for the future management of Lake IJsselmeer.

The central question is twofold:

Which flushing requirements are reported for Freshwater Lakes and (to a lesser extent) Estuarine Systems, required to sustain or reach the desired water quality.

What relevance may be found in (some of) those requirements for the future management of Lake IJsselmeer?

Part 1: International Literature Review (approximately two-thirds of the effort)

A structured review of international scientific and technical literature will be conducted on flushing needs (residence time, water renewal, etc.) to reach or maintain good water-quality in large freshwater lakes, in different continents and settings. To a lesser extent estuarine systems may also be considered.

The review will focus on:

Terminology, definitions, and information sources (literature as in Science Journals, Web-based info, etc.) for flushing requirements, water residence time, renewal time etc.

Methods used to determine or approximate minimum “flushing requirements“ for water quality.

Indicators which are used to deternine flushing requirements and/or appropriate water residence time.

Relationships between flushing rates and (specific) water quality (targets), e.g. salinity control, nutrient accumulation / eutrophication, harmful algal blooms, oxygen conditions, ecological functioning.

Examples from managed lake systems where water allocation competes with environmental and water-quality objectives.

Lessons learned regarding climate change impacts and reduced freshwater availability.

The review will additionally provide some information on:

Part 2: Implications for Lake IJsselmeer (approximately one-third of the effort)

The findings from the literature review will be evaluated on transferability to the IJsselmeer region: Are the flushing requirements, from different lakes in different settings, applicable to Lake IJsselmeer? One or two findings which are sufficiently comparable will be translated to the specific context of Lake IJsselmeer and -to a lesser extent- to Lake Markermeer. The analysis will consider:

A basic analysis of the hydrological functioning of these lakes regarding residence time (lake average, local variety).

Indicative residence-time and flushing requirements relevant for maintaining water quality and ecological conditions. Different water quality standards will necessitate different flushing needs.

Potential consequences of reduced freshwater availability due to higher evaporation and increasing water withdrawals.

Possible complications for the realization of specific goals for nature conservation/nature development.

Possible implications for long-term operation and sizing of discharge infrastructure at the Afsluitdijk.

Preliminary boundary conditions and knowledge gaps for future water management strategies.

The translated findings will be briefly evaluated with respect to:

Deliverables

The study will deliver:

A concise synthesis report of international knowledge on water-quality based flushing requirements for (primarily) freshwater lakes and (to a lesser extent) estuarine systems.

A concise description of the hydrological functioning, residence times/refreshment of Lake IJsselmeer and Lake Markermeer.

An assessment of the relevance of the (literature) flushing knowledge for Lake IJsselmeer and – to a lesser extent, lake Markermeer.

Based on the deliverables 1, 2 and 3: a set of indicative hydrological and operational boundary conditions that can support future decisions on water allocation and investments in discharge and pumping capacity at the Afsluitdijk.

Hier kom je te werken

Over Rijkswaterstaat

Rijkswaterstaat is de uitvoeringsorganisatie van het ministerie van Infrastructuur en Waterstaat en bestaat uit 6 landelijke en 7 regionale organisatieonderdelen. Al meer dan 225 jaar werken we dagelijks aan een veilig, leefbaar en bereikbaar Nederland. We beheren en ontwikkelen de rijkswegen, -vaarwegen en -wateren en zetten in op een duurzame leefomgeving. Samen met anderen werken we aan een land dat beschermd is tegen overstromingen. Waar voldoende groen is, en voldoende en schoon water. En waar je vlot en veilig van A naar B kunt. Samenwerken aan een veilig, leefbaar en bereikbaar Nederland: dat is werken bij Rijkswaterstaat.

Talent als basis, diversiteit als kracht

Rijkswaterstaat is een inclusieve organisatie. Een organisatie die ruimte biedt aan iedereen en die de kracht van de diversiteit van medewerkers gebruikt om samen betere resultaten te halen voor Nederland. Inclusief betekent dat iedereen zich betrokken en gewaardeerd voelt; niet ondanks, maar dankzij de verschillen. Daarom nodigen wij jou graag uit, als jij je herkent in deze vacature, om te solliciteren.

Midden-Nederland

Wil jij werken bij Rijkswaterstaat voor Midden-Nederland (MN)? Deze regio is verantwoordelijk voor het onderhoud, het beheer en de aanleg van (snel)wegen en hoofdvaarwegen in Utrecht, Flevoland en de randen van de omliggende provincies. Met specifieke kennis en expertise beheert MN een van de drukste regio’s van Nederland. De belangrijkste highlights binnen deze regio zijn:

het IJsselmeer: Nederlands grootste zoetwaterreservoir

de wegen rond Utrecht: de draaischijf van Nederland

diverse waterwegen, waaronder het Amsterdam-Rijnkanaal, het drukst bevaren kanaal van Nederland

In totaal werken er ongeveer 350 mensen binnen MN, verspreid over 3 directies: Netwerkontwikkeling, Netwerkmanagement en Bedrijfsvoering.

Bijzonderheden

Additional information

This internship combines research and practical work experience.

The internship is expected to take place over a period of approximately three months in 2027.

The assignment may be combined with other internship projects.

The assignment may be combined with a comparable internship with a literature review focused on estuarine systems and the Wadden Sea

You can only undertake an internship at Rijkswaterstaat if you are enrolled at an educational institution.

Rijkswaterstaat applies a Bring Your Own Device (BYOD) policy for interns regarding laptops and mobile phones. Exceptions may be made in consultation with your internship supervisor.

What we're looking for

You are enrolled in an academic undergraduate or university-level programme.

You study Ecological Engineering or a related field.

You are curious, analytical and eager to learn.

You are comfortable interacting with different stakeholders and colleagues.

You are fluent in English and have sufficient proficiency in Dutch.

€800

Onderzoeksstage

1 feb 2027 -

30 apr 2027

24 - 36 uur

Dit bieden we nog meer

Werk je minder dan 40 uur? Dan is je vergoeding naar rato. Naast je stagevergoeding heb je recht op betaalde vakantieuren.

Indien je geen studentenreisproduct hebt, kom je in aanmerking voor een mobiliteitskaart van Rijkswaterstaat. Let op! Dit geldt alleen indien je geen recht meer hebt op een OV-chipkaart. Indien je wel in het bezit bent van een studentenreisproduct, maar extra reiskosten maakt ten behoeve van de uitvoer van je stagewerkzaamheden dan kun je deze reiskosten declareren.

Rijkswaterstaat plaatst de vacatures op werkenvoornederland.nl, de vacaturesite van de overheid. Wij halen ze daar op.