Tobias Peteler

Summary

“We use stories to regulate our emotions and govern our behavior; use stories to provide the present we inhabit with a determinate point of reference – the desired future. The optimal “desired future” is not a state, however, but a process – the (intrinsically compelling) process of mediating between order and chaos“

Jordan B. Peterson

One of the central tragedies of the impending climate change is the cognitive dissonance that is generated by the general acknowledgment of its existence on the one hand and a lack of corresponding action on the other hand. While the signs of the imminent and drastic impact on climate, society, and landscape are already clearly palpable, the dynamic is still perceived as abstract, distant, and decoupled from the behavior of the individual. One reason for this alienation can be found in the temporal and spatial intangibility of a global phenomenon. Due to their gradual changes, both climate and landscape are often experienced as static entities eluding human perception and subsequently hindering a sense of responsibility and affinity.

To counter the prevailing human exceptionalism and individualism the Heraclitean philosophy proposed a worldview in which existence is not considered static and detached, but rather part of an eternal, dynamic process. Everything is united by being part of a constant change of substance and form. To represent the dynamic and interconnected nature of the physical world, the ever-changing nature of the flow of a river was utilized as a guiding allegory.

Following this line of argument, in my thesis, I aspire to translate this allegory into the physical world. By revealing and unmasking the complex past, entangled presents, and contested future of a tangible and acquainted body of water, the intricacy, volatility, and vulnerability of the global water cycle are made comprehensible to a broader public.

For my project, the river Sihl was determined as a site of intervention. Historically, the city of Zurich identified itself with the calm Limmat River. Meanwhile, the “wild” Sihl was considered to be the inferior river that could be shaped and controlled unrestrictedly according to civilizational will. Along its course, the water of the Sihl is consistently controlled and diverted to serve the ever-increasing demand of the sprawling metropolis for energy, water, and security. Yet, by placing the corresponding infrastructure underground the complex metabolism within the landscape is disguised at first glance.

The dam of the Etzelwerk hydroelectric power plant is a prime manifestation of this parasitic yet hidden approach. Only 80 years after its construction and the concomitant flooding of more than 10 km2 of the Sihl Valley resulting in the eviction of 

500 inhabitants, the Sihlsee is now perceived as a natural body of water. This infrastructure can be considered a key component for the increasing urbanization process of the city of Zurich. On the one hand, the Sihlsee transformed an entire valley into a storage for much-needed electric energy. On the other hand, the dam allowed for unprecedented control over the wild mountain river that was known to flood the lowlands around the city. This new configuration enabled a dense build-up along the course of the river increasingly constraining the flow of the meandering river. In its current state, only a few sections of the former floodplain in the basin of Zurich are still undeveloped.

While in the recent past, a shift towards a more respectful treatment of the Sihl is observed, the attitude is still compromised by a dichotomic view with an original state formed by nature and an artificial state designed by human interventions. In line with this perception, the approach in current revitalization projects tends to recreate and imitate a pseudo-natural state that remains highly artificial and unsustainable. One prominent location where the inherent fragility of the river and its dependency on human interventions is disguised is the Allmend Brunau, south of the city border.

With my project Panta Rhei I respond to this complex reality with two interventions: Regarding the Sihl lake, linear structures are embedded in the southern, shallow part of the lake to promote the formation of wetlands. Bogs offer a diverse habitat for endemic wildlife and, by acting like a sponge, could dampen the stress generated by the highly fluctuating water level of the lake. Both, the swift change of the water level and the gradual formation of wetlands are made perceivable by a bird watching tower that is constantly altering both in appearance and accessibility according to the dynamic of the lake.

At the Allmend Brunau a landscape park is transforming the meadow into a flood plain, drawing a clear line between the protected and exposed. It is intended as a counter proposal to the relief tunnel in Thalwil, which is currently under construction, costing more than 175 Mio. CHF and generating earth movements of more than 260’000 m3. Instead of following the prevailing logic of hiding and disguising infrastructure, the immense effort and invasiveness of human interventions are revealed to the visitors of the park.

In both projects, I seek to question the unilateral human authority over the landscape and strive for a different architectural articulation that accentuates the intricate interplay between human and non-human formative forces. By revealing, exposing, and making tangible the intertwined and dynamic nature of the surrounding waterscape the proposed interventions aspire to counteract a segmented and abstracted perception of the landscape, hinting towards a stronger global awareness.

The Sihl and its Hidden Metabolism

Following this line of argument, in my thesis, I aspire to translate this allegory into the physical world. By revealing and unmasking the complex past, entangled presents, and contested future of a tangible and acquainted body of water, the intricacy, volatility, and vulnerability of the global water cycle are made comprehensible to a broader public. 

For my project, the river Sihl was determined as a site of intervention. Historically, the city of Zurich identified itself with the calm Limmat River. Meanwhile, the “wild” Sihl was considered to be the inferior river that could be shaped and controlled unrestrictedly according to civilizational will. 

Yet, it continuously resisted this exertion of dominance by human agency. Through devastating flooding events or by pressing thick sheets of ice into the territory of the city of Zurich it reminded the residence of its ferocious nature. Revealingly, the name “Sihl”, which is of Celtic origin, can be translated as “the wild” or “the strong”. 

Along its course, the water of the Sihl is consistently controlled and diverted to serve the ever-increasing demand of the sprawling metropolis for energy, water, and security. Yet, by placing the corresponding infrastructure underground the complex metabolism within the landscape is disguised at first glance. 

With the hydroelectric powerplant Etzelwerk the flow of the river is effectively shorted. Currently, only 12% of the river is allowed to pass through the dam into its original bed, while the majority is discharged into the lake of Zurich. 

Downstream in the Sihl valley 25000 cubic metres meters of spring water are collected daily in over 100 spring captures. Using gravitational force, the spring water is directed towards the city of Zurich and consequently revoked from its original watershed. In the city it is either used undiluted as water for over 400 public fountains or mixed with lake water from the waterwork Moos to be used as fresh water by the residents of Zurich. 

Moving closer to the border of the city, the aspect of flood protection becomes increasingly pronounced. Immediately upstream of Langnau am Albis, the newest protective infrastructure is currently under construction. If completed in 2026, a relief tunnel with a diameter of 6.6m is planned to protect the urban area downstream against extreme flooding events. Up to 400 cubic meters of water per second can be diverted from the Sihl river into the lake of Zurich. 

While being distinct in purpose all these infrastructures have in common that they are to a large extend constructed underground, hiding the complex metabolism within the landscape, and thus disguising the unilateral dependencies between the city and the hinterland.

Project Description

With my project Panta Rhei I respond to this complex reality with two interventions: 

At the Sihl lake, linear structures are embedded in the southern, shallow part of the lake to promote the formation of wetlands. Bogs offer a diverse habitat for endemic wildlife and, by acting like a sponge, could dampen the stress generated by the highly fluctuating water level of the lake. Both, the swift change of the water level and the gradual formation of wetlands are made perceivable by a bird watching tower that is constantly altering both in appearance and accessibility according to the dynamic of the lake. While during the high waters during summertime, the tower is only reachable by boat and accessed by a latter, during the dry season it can be reached by food and accessed through an external staircase. The structure as well as the façade are segmented into two parts according to the level of the lake. Everything above the high-water mark is constructed of timber, while all components below are made of steel or aluminum. The lower limit of the façade indicates the average level of the lake during summertime. Consequently, the tower is constantly shifting between being partially submerged and levitating above the surface of the lake. A concrete pedestal, serving as an entry during the dry season, is marking the lowest permissible lake level during summertime. Thus, its emergence serves as an indicator of the start of the winter season.

My second intervention is located on the Allmend Brunau, which is an open plain of about half a square kilometer right at the edge of the city of Zurich. With the addition of a meandering damlike structure this meadow is transformed into a flood plain, drawing a clear line between the protected and  exposed. It is intended as a counter proposal to the relief tunnel in Thalwil. Instead of following the prevailing logic of hiding and disguising infrastructure, the effort and invasiveness of human interventions are revealed to the visitors of the park. Core of the project is an arena that works as a hinge in between the density of the urban fabric and the openness of the plain. Here the dynamics of the Sihl are experienced in twofold: On the one hand it is part of the flood protection and works as a retention basin when the Sihl is bursting its banks. On the other hand, the arena reveals the dynamics of the River on a more subtle way. By being lowered into the ground by almost 5 meters, its floor lies below the high-water mark of the ground water. Thus, if an increased level of the Sihl is raising the ground water table, the arena will be flooded from below, transforming it into a shallow pond. Thus, while being a public space during most of the year, the arena can unsuspectedly transform into a stage of the river.

In both projects, I seek to question the unilateral human authority over the landscape and strive for an architectural articulation that accentuates the interplay between human and non-human formative forces. To follow the advice of Latour and reterritorialize ourselves within the territory that we inhabit means to drastically reconsider our attitude and actions towards all non-human actors. Especially our dominant stance against water and its agency might turn out detrimental in times of a rapidly changing climate. Instead of building higher dams, larger relief tunnels or more sophisticated infrastructure for flood protection we have to learn to relate again to a shared agency and overcome our human abstraction from our environment.