european study tour – REALM research
As an extension to the work that REALMstudios is undertaking with Alluvium for Melbourne Water’s Channel Naturalization Program – the key objectives of integrating livability and environmental outcomes with their assets to create healthy places and people – Tamara Obradovic, Senior Landscape Architect and Urban Designer from REALMstudios Sydney carried out a study tour of a number of recently completed channel restructuring and water management projects across Europe.
The projects ranged from; an award winning renaturation of the river Aire in the rural outskirts of Geneva, to a WSUD driven eco-neighborhood in Nantes, to a closed loop flood mitigation system integrated into an urban plaza in Freiburg and the daylighting of an ancient stream hidden beneath a carpark in the center of Sheffield.
All 4 projects are driven by the fundamental objectives of promoting resilience and livability by regaining nature as well as revealing history of place. Each project is able to create a new site program which creates places for people underpinned by ecological principles and a deep appreciation of the evolution of place and landscape as process.
By creating moments for engaging and interacting with the water in different ways these renaturation projects allow us to gain a deeper understanding of water systems and ways in which they can:
- Help to build resilience
- Successfully be integrated into the urban fabric
- Inspire contemporary WSUD typologies
- Support local ecologies and restore biological functions
- Provide a setting for a diverse range of activities/ experiences for people
- Contribute to place making/ community building
- Strengthen human connection to nature
- Integrate with existing land uses
- Combine with other sustainable technologies – renewables – to support self-sufficiency of an entire neighbourhood
- Reveal a deeper understanding of the geology, geography of an area
- Influence/ reveal the historic evolution of place
- Become outdoor testing laboratories
- Contribute to an evolving landscape
1. The Renaturation of the River Aire (2015) frees the river from its linear constraints and allows it to flow through a newly formed and broadened river bed adjacent to the original canal. The formation of the river bed, inspired by the study of historical traces of ancient meanders of the Aire river, aims to create greater morphological and ecological diversity through an established pattern which accelerates the process of erosion and shaping of the new stream and associated natural habitat. In this way, the project becomes an open air laboratory through careful monitoring of the evolution of the river system and the continuous interplay between the flow of the river and the prepared terrain.
By reducing the hydrological functions of the original canal, the canal now takes on a new function as a rural parkland consisting of a linear sequence of differentiated places and spaces carefully balancing engineering, nature and public amenity. Introducing topography further reinforces a distinct hierarchy of pathway systems that create a considered distribution of people, movements, and site program.
2. The Bottiere-Cheai Eco-District in Nantes, 2015 , is able to draw from its unique geology which created underground water stores and a significant market garden history, to create a new organizational typology which allows an uncovered brook to become the heart and collection point for a new neighbourhood and ensures historic and cultural continuity by keeping the framework of parcels from past agricultural occupation. It provides a careful distribution of community facilities, market gardens, open space areas and medium density living around a comprehensive WSUD program which seamlessly integrates into the urban fabric in the form of raingardens and detention basins.
The landscape takes precedence becoming a continuous system above which float the physical connectors, a comprehensive network of pedestrian pathways ensuring permeability and connectivity through the whole neighbourhood. The project further promotes sustainable practices through rainwater collection and harvesting wind energy for water provision for the allotments.
Whilst the project has been successful in achieving positive ecological and social outcomes, the continuously evolving nature of these types of projects poses questions for long term performance with regards to both public amenity and ecology.
For example, when nutrient levels in the waterway are high then maintenance becomes an issue. Stream vegetation can become a deterrent and obstruction. Over the course of a couple of years the brook has largely become overgrown, limiting access to the water edge in areas, raising issues of safety and access to sunlight along the stream edge.
There is also a noted absence of trees in the project, especially in the streetscape. Whilst understorey plantings support bio-filtration processes and provide greening, trees are essential to maintaining human comfort and responding to climate change, particularly in harsh urban environments.
3. The Zolhallen Plaza in Freiburg (2010), provides a closed loop flood mitigation system, disconnected from the formal collection system, which supports infiltration, storage, and ground water recharge whilst creating a useable public space. Blurring the boundaries between the built and the natural it cleverly integrates historical features/forms and materials to create subtle level changes and division of space and planted zones. The resultant plates accommodate a variety of experiences including a series of intimate seating areas and a large plaza space for community gathering and events.
The plaza has, however, suffered substantial plant loss over the years. In harsh urban environments, appropriate plant selection is critical to ensuring performance over time with particular consideration to fluctuating seasons/rainfalls and climate change.
4. The Porter Brook Pocket Park (2016), in the centre of Sheffiled is a fine example of how a small project can be a catalyst for urban regeneration and environmental improvement. Located in the heart of Sheffield’s industrial zone, a small stretch of the River Porter which has previously been hidden in a culvert buried beneath a carpark has been revealed and naturalized through a specific habitat creation scheme for trout. A small ampitheatre has been created to provide a small riverside park, a green oasis in the centre of Sheffiled, which both aids with flood mitigation and becomes the first section of riverside walk as part of a broader strategy for reconnecting the city with its waterways.
There is, however, already evidence of weed infestation in the stream. Once again it becomes clear that maintenance is a critical success factor for renaturation projects such as these (especially in urban environments) and if left can limit the biological functions of the waterways.