Nature-Based Solutions by Drinking Water Supply Company PWN We spoke to Ruud van der Neut, senior drinking water engineer and project manager, and researcher Tim de Groot about the LIFE WATERSOURCE project - led by PWN. Their work focuses on pioneering nature-based solutions to strengthen the ecosystem of Lake IJsselmeer, ensuring sustainable drinking water and resilience against climate change, salinization, and emerging contaminants. PWN is the primary drinking water supplier for
Climate Buffer Lake IJsselmeer
the province of North-Holland. Over 70% of the drinking water which is produced by PWN has as source water from Lake IJsselmeer. This source is increasingly under pressure due to climate change, leading to more frequent extreme weather events such as drought, heavy rainfall, and extreme heat waves (KNMI 2023). These conditions impact both the quantity and quality of the water in Lake IJsselmeer. Predictably, the likelihood of scenarios where the annual average water becomes too saline for the drinking water production, like the dry summers of 2018 and 2022, is increasing. Future projections (2050) anticipate salinization events every 8 years and water shortages every 5 years, according to the stress-test for the IJsselmeer area in 2021 (Pouwels et al 2021). Furthermore, the surface water of Lake IJsselmeer poses challenges to purify due to the presence of suspended solids and organic material in the water, as well as the increase in contaminants of emerging concern (CECs), like pesticides, PFAS, microplastics and pharmaceuticals. Also, the likelihood of water quality deterioration (such as algal blooms) due to a combination of climate change and insufficient ecological resilience is increased. On top of this, PWN can expect an increase in customers of 300.000 households due to new housing projects. To address these challenges, initiative-taking climate adaptation measures are essential.
The Klimaatbuffer IJsselmeer (KIJ) project, or ‘Climate Buffer Lake IJsselmeer,’ proposes a system of deep-water storage basins surrounded by a natural purifying landscape to support PWN’s drinking water production. These interconnected basins, approximately 25 meters deep with variable water levels, serve to pre-purify water and
final treatment step using bank filtration in which a — typically applied along rivers but here integrated within a still-water basin — exemplifies a nature-based solution to enhance water purification efficiency. The KIJ concept integrates these natural pretreatment methods, although their full potential and optimal configurations remain to be explored.
“The LWS project proposes a groundbreaking approach to ensure a secure, sustainable drinking water future for North-Holland, aligning human activity with broader ecological goals by using nature-based solutions where possible and technical solutions where necessary.” increase storage capacity, giving PWN greater flexibility in selectively sourcing high-quality water from Lake IJsselmeer. Sediment from the basin excavation will be used to create this surrounding purifying landscape, which enhances local ecology and contributes to additional water filtration. The gradual land-to-water transition around the KIJ boosts biodiversity in Lake IJsselmeer and can possibly offer recreational spaces for the community in the future. The natural purified water is stored in the deep-water basins, where a
Demonstration Project: LIFE WATERSOURCE Part of this exploration is the LIFE WATERSOURCE (LWS) project. Demonstrating the Climate Buffer Lake IJsselmeer concept is essential to ensure a secure, climate-resilient drinking water supply for North-Holland according to senior drinking water engineer Mr Van der Neut, water quality engineer and project manager. With climate change introducing greater variability in water availability, salinization, and emerging contaminants, a small-scale
Water inlet towards a purifying landscape.
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