Exploring Macrophyte Waste in Architecture
Water-Based Living is an initiative that reimagines the role of water in shaping architectural design and daily life. The first part focuses on finding ways to repurpose blue biomass waste in construction, offering a sustainable alternative to traditional disposal in landfills.
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Eutrophication occurs when bodies of water like lakes, rivers, and coastal areas accumulate excessive nutrients, especially nitrogen and phosphorus. This often happens due to runoff from fertilizers, sewage, and animal waste. A significant consequence of eutrophication is the rapid proliferation of algae and macrophytes. These algal blooms can be detrimental, releasing toxins that threaten aquatic life and human health. One method to mitigate eutrophication is aquatic plant mowing, a practice implemented in several countries worldwide.
Aquatic plant mowing controls overgrown macrophytes, reduces nutrient overload, improves water flow, supports biodiversity, and protects aquatic fauna. However, experts such as botanists Sigitas Juzėnas and Jūratė Karosienė warn against over-mowing and emphasize proper permissions and biomass disposal. Their interviews are available in the e-booklet.
While several factors influence the decision to mow aquatic plants, this practice is widely implemented in cities around the world, including Amsterdam, Berlin, and Paris. Typically, the collected biomass is transported to the outskirts, for agricultural use or bioenergy production. But, what if this locally sourced material could be used to construct small, or even larger, structures within the cities themselves?
In France, Paris is focused on reintroducing public swimming in its canals and the Seine, raising concerns about water quality and the risk of aquatic plants entangling swimmers.
In French, aquatic plant mowing is called faucardage, a term coined by Prefect Dieudonné in the early 19th century to describe the cutting of aquatic plants in waterways to prevent blockages.
Map of Faucardage Operations in the City of Paris
While faucardage happens across France, little is known about its extent in Paris, where 180 tons of aquatic plants are removed annually, a number that is expected to rise. It has been confirmed that aquatic plant mowing takes place in the Canal Saint-Martin, the Canal de l’Ourcq, as well as the Bassin de la Villette and the Arsenal.
The cut aquatic plants are sent to a storage site to be used as land deposits for agricultural operations. Although this disposal method has a relatively low environmental impact, there is potential for a more innovative approach: utilizing the biomass as a building material. This alternative could not only reduce transportation costs to the outskirts of Paris but also contribute to more sustainable construction practices. The following experimental prototypes could be applied in this approach.
Prototype Creation
The prototypes were created with a focus on simplicity and sustainability, using second-hand materials such as repurposed clay, discarded containers, and leftover wooden window frames. Biomass was collected, categorized into plants suitable for weaving or mixing with binders, and analyzed. All prototypes were created in Lithuania using biomass collected in Kėdainiai. However,this technique could be applied in many other regions as well.
For the acoustic panel experiment, an old wooden window frame (157 cm by 55 cm) was repurposed. Holes were drilled to insert wooden dowels, forming a grid for weaving. The first prototype used Stuckenia pectinata, a plant commonly found in waters affected by eutrophication, for the weaving.
The following experiment drew inspiration from the traditional wattle and daub technique. Small clay and blue biomass bricks were created by mixing various ratios of clay and ground aquatic plants until a solid consistency was achieved.
The mixture was then molded and left to dry. Multiple variations were tested to explore different consistencies, and in some cases, flax seeds were added to enhance the composite’s strength.
For the lime binder prototypes, materials included pozzolan, quicklime, water, and ground blue biomass: the same biomass used in the clay brick prototypes. During the experiment, a 47×35 cm panel was produced.
To enhance scalability, the clay and blue biomass prototypes can be adapted for insulation by adding dried aquatic plants between a double wooden frame, finished with a clay coating. On a larger scale, unshredded plants could also be incorporated for greater flexibility. Depending on the building’s thermal and structural requirements, either dried or undried aquatic plants may be used. However, material consistency may vary by location due to the availability of different types of biomass, which will require further investigation. Overall, this concept holds promise for sustainable construction in local communities.
During building demolitions, many discarded windows are typically thrown away, but they can be creatively repurposed for interior use. Similar to the acoustic blue biomass prototypes, these windows could be transformed into acoustic panels for music studios, conference halls, and offices, adding both soundproofing and decorative appeal. While this technique may currently require time and effort, collaborative efforts could help make it a valuable and innovative approach in sustainable design practices.
This experiment highlights the untapped potential of aquatic plants, often viewed as waste or an ecological burden in water systems: to inspire innovative, eco-conscious building practices. By moving from conventional disposal methods to a regenerative design approach, new pathways open for reducing environmental impact and integrating circular economy principles within the architectural field.
As urban centers worldwide confront escalating environmental challenges, the practices explored here offer a vision of urban growth aligned with ecological health and resilience. This research marks a significant step in transforming aquatic plant waste into a valuable resource that benefits communities, supports biodiversity, and reduces the environmental costs of construction. Through these strategies, architects and planners gain a framework for creating regenerative, water-centric spaces that integrate harmoniously with surrounding ecosystems.