An interesting project in St. Paul, Minnesota emerged in this Star Tribune article “Work could begin soon to bring St. Paul’s Phalen Creek back to the surface,” which highlights the mix of ecological and cultural benefits of urban stream daylighting. Through a focus on both the benefits to wildlife habitat and ecosystem function and the connection of cultural heritage for native people and early immigrants to the area, it shows a rich story that is told through multiple lenses to provide solid rationale for daylighting projects.
One major idea of daylighting is visibility. As mentioned in the Star Tribune article, this is a typical case of burial of creeks for development, but like many other areas, the perceptions have shifted and the value of historical waterways are being restored. A big part of that is pointed out by Ramsey-Washington Metro district watershed project manager Paige Ahlborg, watershed project: “Another benefit is just restoring a community’s connection to the water,” Ahlborg said. “Seeing it makes it harder to do things that harm it. We still have a number of people who think that ‘if I put something down the [storm]sewer drain, it will be treated.'”
The history of places is expressed in place names. From the Capitol Region Watershed District site, some history on the current name: “Swede Hollow on the City of Saint Paul’s East Side is a historic immigrant neighborhood dating back to the 19th century. This lowland valley includes a portion of a stream from Phalen Creek to the Mississippi River. After housing was removed following the turn of the century, the city created Swede Hollow Park and placed some of the stream flow in a storm sewer pipe to complete its path to the river.”
Image of Phalen Creek burial in the 1920s. – via Minnesota Historical Society
As is the case with most places, the story and names is often told in European terms (i.e. Swede Hollow). The creek name as well comes from Edward Phalen, one of Saint Paul’s original colonists, who settled on the banks of the creek in 1838. Prior to this arrival, the history of place stretched far earlier as referenced in the Lower Phalen Creek Project, a native-led project:
“This creek served as a corridor for the Dakota people who lived here, as they made their way up the chain of lakes by canoe to White Bear Lake – one of many areas where they gathered wild rice.”
The daylighting has both ecological and cultural benefits. In the Star Tribune, Lower Phalen Creek Project Executive Direction Maggie Lorenz, who is both Dakota and Ojibwe, mentions: “[Phalen Creek] is an essential part of the community — it will bring more natural habitat and it means more opportunities for recreation and stormwater management. And, from a cultural perspective, we are really interested in restoring the land and taking care of the land according to our traditional teachings.”
While the goal is to extend daylighting all the way to the Mississippi River, one the first legs connects from Lake Phalen and Maryland Avenue as shown in this enlarged plan, highlighting the ecological benefits, including fish passage and enhanced in-stream habitat, establishment not just of the creek but adjacent floodplain wetlands to provide resilience and habitat for amphibians, and upland prairies that provide native riparian habitat supporting birds and pollinators.
“Consultants at Inter-Fluve, Inc. produced this visual to represent the proposed location, general design elements, and predicted habitat benefits of a restored stream channel of Phalen Creek at the Lake Phalen / Maryland Avenue project site.” via Lower Phalen Creek Project
A ton of additional information is at the LPCP site, including graphic summary of the project is found in a brochure that connects the dots between the cultural and ecological.
A project from artist Cristina Iglesias (see a post of some of her previous work here) again dives into the idea of hidden hydrology, this time in New York City. Entitled Landscape and Memory (referencing the title of one of my favorite books by Simon Schama), the work unearths a buried stream in Madison Square Park.
From The Architect’s Newspaper: “Manhattan is crisscrossed by streams and rivers that have since been buried but continue to flow, flooding their banks and the basements above when it rains. For Landscape and Memory, Iglesias will exhume an impression of Cedar Creek, which once flowed beneath where the park now stands today.”
From the Madison Square Park Conservancy, some more info: “Nodding to historian Simon Schama’s major 1995 volume of the same name, which surveyed the history of landscape across time and terrain, Landscape and Memory is informed by Iglesias’ research into the history of the site. For the project, Iglesias located and studied antique maps that documented the water flow beneath Madison Square Park, where the Cedar Creek and Minetta Brook once coursed for two miles before flowing into the Hudson River. With nineteenth-century industrialization, streams like the Cedar and Minetta were buried underground to create additional land for building sites, underground drains, or sewers. Through Landscape and Memory, Iglesias renders this buried history visible again, inviting viewers to contemplate centuries of transformation of urban sites that were once natural.”
Excited to hear more about this and see more images, as the sketch is a bit… sketchy. You can check out the full press release here for more info. Based on some of her previous work it will be wonderful in execution. The work will be installed from May 23, 2022, through December 4, 2022 so those in New York City go check it out and report back.
It’s more of a deep dive into some of the research, but the general thrust is that water intrusion in systems has reduced capacity, and that the intentional encasement of streams and springs in pipes reduces the capacity of infrastructure which has a significant economic, environmental and social implications for the infrastructure, as it reduced the baseflow reduces the overall effectiveness of gray infrastructure.
The typical mechanism for intrusion into pipes is related to cracks, which is assumed to be residual groundwater entering pipes in ‘dry weather’ times, where there should be no flow into the system. Groundwater intrusion should not be discounted, but there are other sources of intrusion that are typically not considered, specifically “capture of streams and springs” that impact combined systems capacity.
The figure below shows the change in baseflow and runoff response due to the intrusion of the additional water from streams and springs.
The paper continues to identify the issue, also highlighting the lack of research on this topic, and answers some fundamental questions about how this capture occurs, how to identify it, what is the magnitude and impacts, and ways to manage it. Always interested in language, one item of interest explores key terminology – culverting, extraneous water, groundwater infiltration, sewer inflows and the key element, stream and spring capture. The wordplay is compelling, with some uniquely evocative terms emerging such as parasite flow, misconnected surface waters, sewer leakage and illicit connections all telling a story of water that is in a sense, ‘out of place’.
The how and why is interesting. The most basic version is to take a free flowing stream and incorporate it into a pipe (Type A in graphic above). “Urban streams were frequently culverted and buried, especially during the period of rapid urban expansion in the 19th century.” It’s not a stretch to show that the literature confirms that “old sewers were frequently the covered channels of brooks”, as early development merely hid the streams, but didn’t generate as much additonal flow to overwhelm the piped streams. This happened with additional development and expansion of cities and impervious zones. Often the buried streams become the names for the sewers themselves, such as those specifically mentioned in the article like Garrison Creek Sewer in Toronto and Minetta Brook Sewer in New York.
The baseflow in the streams, unlike sewage, is clean, so the incorporation into pipes and transportation to wastewater treatment plants means additional strain on purification infrastructure with water that doesn’t need treatment. This relates to the original conceptual idea of the Tibbetts Brook example today, with a clear path to remove ‘clean’ water that is reducing combined capacity and overall resilience to deal with larger storms.
Additional capture happens by interception (Type B in graphic above). The most visible example is the massive interceptor sewers in London developed by Bazalgette in response to the ‘Big Stink’ in the the 1850s, acting as a divertor to sewage entering the Thames. This model was copied around the globe, with numerous examples of streams disconnected from their outfalls and no longer making it to their original destinations in the name of water quality. Portland has a large, expensive example of this called the Big Pipe. Many other cities have similar interceptor systems.
Another mode of is by directly capturing and draining spring and seeps in combined sewers, in this case through leaky pipes with cracks and joint openings. Beyond being shoddy construction, this was intentional, designed as deliberately leaky to provide drainage in areas of perched or high groundwater. The 3 types are summarized graphically above, showing variations of combined sewers and stream capture typologies.
The connection here to lost rivers is outlined in the article: “Not all streams and springs are fully captured by these modes of entry. London’s lost rivers diverted into the High, Mid and Low Level Interceptors to the WwTW, (wastewater treatment works) such as the Walbrook, Fleet, Tyburn and Westbourne, do still discharge to the River Thames during heavy storm events, where the original courses of the rivers serve as CSOs.” This is also a pattern in the United States (New York) and Asia (Tokyo) where many of the piped streams never make it to their original drainage water bodies.
The 19th Century was a historic time for burial of waterways, as the rate of urbanization outpaced the ability of natural streams to remove wastes. Thus: “Urban streams that had become open sewers were frequently culverted and buried to provide more sanitary conditions, and this concept is a popular narrative predominantly explaining the conversion of many smaller watercourses to combined sewers (type A).” Beyond the main drivers of pollution reduction and removal of the streams to create land for development, the introduction of seeps and springs provided some necessary baseflow to ‘flush’ sewers as a method of ‘self-cleansing’, and thus was in common practice in sewer design.
It is obviously difficult to identify these captured streams, as they exist under the surface and the original hydrology has been erased. This is where hidden hydrology methodology, using mapping and other primary sources to show where routes of surface flows used to run. Often these were parts of combined sewers, but in some cases the streams were just dumped into pipes. While still important, it is less impactful to combined systems and wastewater treatment facilities as they are often just draining into the same waterbodies that the original creek flowed in to.
Urban exploration is another method of finding routes of streams mentioned (which I’ve covered in depth here in many cities). Mapping of sewers and streams supplement this work, with many cities having robust sets of maps dating centuries in the past to fill in gaps of knowledge of what was there and what was replaced. More sophistical modeling can be helpful, but simple cues like place and street names and other subtle clues can also be extra data to be used to pinpoint old routes of waterways. As mentioned:
“Relevant information on lost urban watercourses helps to establish the pre-development hydrology, but the usefulness of historic maps depends strongly on spatial and temporal coverage, with many older towns and cities having altered the hydrological landscape before the first available maps. The smallest streams and springs may also not be marked on maps at certain scales, particularly intermittent and ephemeral channels.”
The ability to quantify these captured streams is equally challenging – there is adequate knowledge of the phenomenon but lacking in specific data on volumes, routes and baseflow contributions to the systems. While even knowing the levels would be helpful, measuring current flows will yield radically different results today versus pre-development conditions. When quantities can be estimated, the economic benefits can be modeled to see impacts, but this is not common. How the water is distributed is also variable and depends on unique qualities of each stream.
The major consequences are two-fold. First, the introduction of clean stream water increases the amount of water handled by treatment plants, which has larger infrastructure costs in terms of facility construction and operations. Second, loss of surface streams has impacts to habitat, less ecological connectivity, and overall less ecosystem services, including amenity value. It can even have secondary impacts on urban heat by reduction of linear corridors of riparian vegetation. While the anecdotal benefits of ‘flushing’ using the streams was developed early-on, it’s not understood if there’s actual value of these approaches.
A summary of the impacts on the industry are included:
More land and costs needed for wastewater treatment infrastructure
Additional operational costs and use of chemicals
External impacts, such as public health impacts of CSOs, impacts due to loss of ecosystem services due to diversion of local streams, and economic losses.
There’s a more detailed cast study from Zurich, Switzerland that’s worth exploring more. In summary, the authors mention the city as a pioneer through “innovative management of capture streams and springs in combined sewers,” typically through separation using daylighting. This was driven by understanding the “lost social ad environmental values of watercourses that had become culverted and had historically been used as wastewater sewers.”
The benefits to the public include amenity spaces, and also more efficient infrastructure through additional capacity. This dual benefit is key to the Stream Concept, and became codified into planning policy and laws. The dramatic reducing in streams due to urbanization is similar to other cities, with development displacing larger areas of open space and burial of streams, many of which were converted into combined sewers between 1850 and 1980 as seen in the figure below.
The transformation of streams from this point in 1980 shows the changes in approach used by Zurich in the Stream Concept. This is outline in the existing condition (1) which includes stream capture in a traditional combined sewer system, a severing of the hydrological system and piping; the first transformation (2) consisting of separation of the combined systems to removed capture streams, and eventually the final phase of the Stream Concept (3) “separating captured streams and springs into daylighted urban watercourses.”
An important aspect which reflects my approach allows for hybrids of ‘daylighting’ without and zero-sum outcome of daylight or nothing, but allow for a continuum of potential options – as I’ve discussed, between art and science (abstraction vs. pure restoration) or more specifically, interventions that can be located in a triad of artistic, design, or engineering. The street streams, per the articles:
“Naturalistic stream channels and riparian corridors are used where possible, but where space is limited, engineered “street streams” are installed. The latter may have a lower ecological potential, but nevertheless offer architectural value in urban areas.”
The two different typologies seen above show a ‘naturalistic’ approach in a more suburban location (Albrisrieder Dorfbach), versus the more urban ‘street stream’ in Zurich (Nebelbach). The street streams may mimic green infrastructure solutions like green streets as linear corridors, with the conceptual difference of being able to be hydrologically connected from source to outfall to re-connect the old stream corridor, versus merely being site specific insertions.
The article concludes that there is value in disconnecting streams and springs from combined systems (or if we could spin time back, not connecting them in the first place), with economic, environmental and social benefits. The diversion of clean, constantly flowing water out of combined systems provides capacity, and by daylighting (vs. piping) these streams, we have the additional ecosystem benefits. The need for more research is mentioned: “By using daylighted urban streams to convey the clean water baseflow, highly promising social and environmental benefits have been suggested; an independent peer-reviewed appraisal of this approach would be strongly recommended.” Since this is a 2013 article, I’m curious what additional scholarship has emerged in the last decade.
I also am intrigued by two of the US examples identified in the article were in Portland and Seattle, both of which mention combined sewers with springs running in them. Worthy of more exploration, but both of these do related to a location where a stream was buried and integrated into the pipe infrastructure of the city, which was common in many streams in both cities (for instance Ravenna Creek in Seattle, or Tanner Creek in Portland). Perhaps with the continual increasing impacts of climate change on these systems would drive another look at some daylighting to increase the resilience of the pipes to handle more capacity, while also providing habitat, amenity, recreation, and a range of other essential urban ecosystem services?
Full Citation: A.T. Broadhead, R. Horn, D.N. Lerner, Captured streams and springs in combined sewers: A review of the evidence, consequences and opportunities, Water Research, Volume 47, Issue 13, 2013, Pages 4752-4766, ISSN 0043-1354, https://doi.org/10.1016/j.watres.2013.05.020
Header Image: Figure from the article: Historic loss of Zurich’s streams (water in blue) with increasing urbanisation (grey).
The recent article in the New York times on the daylighting project at Tibbetts Creek reminded me, based on some of the comments, of the poem by Robert Frost called “A Brook in the City”. I knew of the poem, but hadn’t really made the connection to hidden hydrology, but the tones of industrialization that . Some analysis of the poem explains the context, as the poem “was written somewhat in early 1920 when history was witnessing Industrial Revolution and urbanization. It was at that time man became an evil and the outcome was the devastation and extinction of nature.”
West Running Brook No. 3 – J.J. Lankes (via Book Porn Club) – one of the woodcuts of another Frost collection of poems ‘West Running Brook’.
The brook becomes the symbol for that devastation, and the domination of nature the culprit: “…because of man’s modernization the brook which was a symbol of force is now nothing more then a weak and meek sewer. At night it still flows. A time would come when people would forget that there was a brook which existed. It would only exist on maps. The poet wonders if man could ever ever understand his mistake.”
An interesting piece of poetry that hits at the root of loss, memory, and the essence of hidden hydrology. Sad and beautiful, be still resonant a century after it was written, and somewhat poignant to consider as we daylight and restore the brooks… reversal of some of that old wounds made right. Enjoy.
A Brook in the City – Robert Frost
The farmhouse lingers, though averse to square With the new city street it has to wear A number in. But what about the brook That held the house as in an elbow-crook? I ask as one who knew the brook, its strength And impulse, having dipped a finger length And made it leap my knuckle, having tossed A flower to try its currents where they crossed. The meadow grass could be cemented down From growing under pavements of a town; The apple trees be sent to hearth-stone flame. Is water wood to serve a brook the same? How else dispose of an immortal force No longer needed? Staunch it at its source With cinder loads dumped down? The brook was thrown Deep in a sewer dungeon under stone In fetid darkness still to live and run— And all for nothing it had ever done Except forget to go in fear perhaps. No one would know except for ancient maps That such a brook ran water. But I wonder If from its being kept forever under, The thoughts may not have risen that so keep This new-built city from both work and sleep.
Header image – excerpt of woodcut from J.J. Lankes from another Frost collection of poem, “West Running Brook” – via Book Porn Club
I feel like I’ve been overcomplicating my explanations of the connections of climate change and hidden hydrology and Sanderson just nailed the concept in a few words. While the explanation is simple, the complex interactions between that hidden (buried) strata beneath the surface that have been erased from our urban areas and how these areas are poised to re-emerge in the urban sphere in dangerous ways as zones of flooding during extreme weather events is a topic worthy of more examination.
We have plenty of extreme events and flooding here in the Pacific Northwest to see this phenomenon play out in similar ways, causing water levels to rise in creeks or streams, or with high-precipitation rainfall that accumulates faster than it can drain in cities. Hurricanes, however, seem to be a special case in exacerbating issues just by the sheer scale and concentration of impacts in a short duration. These continual, cyclical events along the Eastern Seaboard ad Gulf Coast highlight the danger or urban flooding and as Sanderson points out, offers clear connections with the current flood events in locations of historical, now buried, waterways.
Hurricane Sandy opened many eyes to the risks. At the time there were a number of articles that caught my eye, particularly the idea that inundation and flooding at the margins were related to the idea of land filling and shoreline creation and the margins, replacing natural shorelines with hardened urban edges and bringing development out into these areas. In this June 2013 article in the Daily Mail, “How Hurricane Sandy flooded New York back to its 17th century shape as it inundated 400 years of reclaimed land.” the .
Expanded Shoreline of Manhattan from 1650-1980 – via Daily Mail
Looking at the extent of flooding in Hurricane Sandy (map below) and a number of studies on flood risk, it’s possible to do a quick mental overlay ad show the vulnerability related to the ‘made land’.
This is obviously not unique to New York City, and I’m interested in researching other places where flooding and made land has a similar correlation. In these cases, the conceptual connection started to take shape in the impacts of flooding at the edges, and how filled land can become a marker for shoreline flooding, which will inevitably be impacted more by sea-level rise in cities that have claimed1 this land from their adjacent water bodies.
The most recent events, during Hurricane Ida, Sanderson points out, go even more fine grain to individual inland areas where historic creeks or wetlands intersect with, such as Central Park (where wetlands were removed in construction of the park) and various other areas, including fatal incidents of basement flooding, in areas of where creeks, streams, wetlands and tideflats existed even up the the early 1900s.
A specific example of flash flooding in the subway in Manhattan at 28th Street and 7th Avenue (see video on Twitter post which is bonkers for both the intensity of the flooding and the utter lack of reaction from New Yorkers watching on the platform). As the article mentions the location of the flooding: “Right in the middle of a wetland clearly shown on 18th-century maps, the headwaters for The Old Wreck, a stream that fed Sunfish Pond, on the south side of Murray Hill, before reaching the sea at Kip’s Bay.”
18th Century Map showing location of wetland in area of 28th Street Station – via NY Times
The takeaway of cause and effect is summed up by Sanderson:
“The city even has a map where the extreme flooding happens, compiled from 311 reports and official observations. It is, for all intents and purposes, a map of the old streams.”
The action here is simple – avoid damage and loss of life from these events, because they are not going to stop any time soon. Increase resilience (both social and eco/hydrological) helps, and as the OpEd mentions, there are many other socio-economic factors involved that increase risk. But Sanderson looks for solutions (the old ways of knowledge) and points out “The losses are mainly the result of our inability to read the landscape where we live and conceive fully what it means to live there. We need to see the landscape in new, by which I mean old, terms.”
Where we location development must respect the hydrological history, as we’ve seen time and time again our inability to overpower nature, and ultimately the failure of forgetting what we buried. Worth a read for the article is a great explication of a terribly absent land consciousness and ethic, but at a practical level, there are some hints that allow us to connect historical ecology to solutions such as making room for water and using Nature based solutions such as wetland restoration and tree planting, many of which are continuing to take a rightful place in climate and resilience plans.
Perhaps the ending, again, for all of our complex machinations, allows us to think more simply about the solution and find opportunities for this simple action:
“Let’s let the streams run free.”
Endnotes
Maybe my own rant, but there’s a whole series of posts and discuss related to the concept of ‘reclaiming’ land from the sea, which is the common parlance in this case. I do prefer ‘claiming’ and the idea of ‘made land’, as it’s really impossible to reclaim something you never possessed in the first place.
Header image – NY Times – photo by Anthony Behar/Sipa – Associated Press
A recent article on Belfast’s River Farset jogged my memory that I’ve got a ton of great info the hidden rivers in many cities around the world, so figured I’d start writing about them. For this post, I’ll focus on Belfast, and return shortly to discuss Dublin to round out Ireland, then move on to other locales. As mentioned in the most recent article, “For 170 years, the river that gave Belfast its name has been buried underground in a hidden tunnel.” It goes on to discuss how, similar to many stories of cities worldwide, the river was slowly changed from vital aquatic resource that fueled manufacturing such as linen mills, to it’s transformation as dumping ground, leading to the eventual encasement: “One million bricks and 40 years later, the last section of the Farset that flowed through the city centre was buried underground in 1848, and it has remained hidden from sight ever since.“
In the 1800s, the Farset helped to power Belfast’s textile mills, factories and distilleries PHOTO: De Luan/Alamy (via Daily Trust)
From the article:
“Belfast, or Béal Feirste (‘the sandy ford at the mouth of the Farset’, in Irish) not only owes its existence to this river, but also its growth and early prosperity. Yet, for the last 170 years, this ancient waterway has been sealed off from the outside world by a series of tunnels, and is largely forgotten by those walking just above it.”
The desire to open up the Farset is a common theme, with plans “…to redevelop land around an exposed part of the river and also produce a full heritage package – including an exhibition, Farset app, public information signs, and tours with trained guides – that will highlight the heritage to local people and also attract tourism.”
Another article echoing this sentiment in the Belfast Telegraph traces “The lost river that gave Belfast its name” and offers an exploration as well: “Old drawings show a bustling river which powered Belfast’s industrial development and ferried traders into what is now High Street. But most locals would be hard-pressed to pinpoint exactly where the Farset flows before it reaches the city centre – because almost the entire route is now hidden beneath our feet in the form of culverts. The Greater Shankill Partnership recently revealed it wants to transform one of the few open stretches of the Farset into a public amenity as part of its long-term Shankill Greenway plan.”
Tracing the source of the Farset river in Belfast from the hills over looking Belfast to its end at the Lagan Weir Shankill cemetery where the river behind – image via Belfast TelegraphTracing the source of the River Farset in Belfast: river ends at the Big Fish at Customs House Square –
This similar theme is expressed in stories from 2015 from the BBC, “Hidden History of Belfast’s lesser-know rivers brought to the surface”, which includes the Farset, as well as the Blackstaff rivers, both of which “determined the shape of the city that grew up around the narrowest bridging point of the Farset, where High Street is today.”
A computer image showing the original course of the rivers Farset and Lagan in Belfast – via BBC
Additionally, the Connswater, which was featured in Van Morrison’s song “Brown-Eyed Girl“, but also has a larger history as a locus of whiskey production, ” In Victorian times, two-thirds of whiskey exported from Ireland came from Belfast, and around half of that came from two distilleries – the Connswater distillery and the Avoneil distillery. “ Today, remnants run under the 400-year old bridge in east Belfast. Portions of the river runs through Orangefield park and supports wildlife, “The river used to run along fences at the back of the houses, which were susceptible to flooding. Instead of building floodwalls, here the river has been ‘moved’ to become a central feature of the park.”
The 400-year-old Connswater Bridge in east Belfast – via BBC
HEADER: Partially hidden view of River Farset in Belfast – via Belfast Telegraph
An interesting case study in hidden hydrology from a region I’ve yet to discuss, Greece. Via the Telegraph, an article “Athens hatches ambitious plan to uncover fabled river, once the haunt of Socrates, and turn it into a park.” The river in question is the Ilissos, which, due to lack of maintenance on the subsurface tunnel in which the river flows has led to structural issues that has caused issues with the tram line running on the surface, and opened up opportunities for restoration of this ancient waterway. As mentioned:
“An 1821 water colour of the Ilissos River and the Temple of Olympian Zeus” – via Telegraph (image credit Alamy)
“Urban planners have suggested that rather than spending millions of euros on reinforcing the tunnel and repairing the track, the tram line should be diverted along a different route and the river opened up. They are proposing the creation of a park along a one mile stretch of the formerly forgotten river.”
Some context on the significance of this river, via the HYDRIA Project, “Ilissos river was considered in antiquity as the second main river of Athens, forming an horizontal landmark in its southern and eastern sides. Ancient writers mention various activities by its banks, varying from civic processes, cults -including a sanctuary dedicated to the river himself, by Ardittos hill- or social walks and philosophical endeavours in idyllic landscapes, as for Socrates and his disciples (Plato, Phaedrus 229-230, link). “
View of Athens from the River Ilissos – painting by Johann Michael Wittmer – via Greek City Times
Due to the dry climate, the Ilissos and the other river in Athens, the Kifissos, are often dry, as mentioned in the article. “Given Greece’s dry, hot climate, neither is huge – they are nothing like the Thames in London or the Tiber in Rome.” They do, however, act as places for floodwaters to run after winter rains, and the depths can reach up to six feet.
From the BBC “Athens to open up ancient river“, the plan by Nikos Belavilas from the Urban Environment Lab shows the route of the proposed daylighting, restoring it after it was paved over in post-WWII development. You can see the location of the current configuration in the context of the historical routing above, including the Stadium and the Temple of Olympian Zeus, built by Hadrian.
Beyond daylighting, the restoration also has bigger implications, as a strategy to avoid future issues. As mentioned in the BBC article:
“But it is not just a simple matter of reclaiming the city’s past, but also of saving its present.”If the Ilisos tunnel collapses, it will block the natural course of the river, and could flood the entire city centre,” Mr Belavilas warns – “That doesn’t bear thinking about.”
Currently, only a small section is now visible on its path from the mountains, as mentioned in the Telegraph: “It originates in the mountains on the edge of the city and eventually flows into the Saronic Gulf, after passing almost unseen beneath the streets of the capital. It does emerge briefly, in reed beds behind the Temple of Olympian Zeus, which was built over several centuries starting in the second century BC. “
The only uncanalised part of the bed of Ilissos river that once ran outside the old city of Athens. – via Wikipedia
HEADER: River Ilisos and Stadion Bridge, ca. 1900 – via Wikipedia
“Old Denver pulsed with H2O, water that snaked through the creeks and irrigation canals crisscrossing Colorado’s high prairie before 150 years of urban development buried most of them or forced them into pipes.”
A similar story to many cities across the globe, “…developers focused on filling in creeks to make way for the construction of railroads, streets, smelters and housing — all laid out across a grid imposed on the natural landscape.” This can be remedied today “…by reconstructing the urban landscape where possible, they’ll slow down water, filter it through vegetation to remove contaminants, control storm runoff and nourish greenery to help residents endure the climate shift toward droughts and rising temperatures.”
DENVER, CO – AUGUST 27: Newly planted grasses grow along Montclair Creek on August 27, 2018 in Denver, Colorado. The City of Denver is working on restoring the creek to help with future flooding. (Photo by RJ Sangosti/The Denver Post)
It’s heartening to see this large of a paradigm shift, and engineers, such as Bruce Uhernik, whom quoted saying:
“We’re just trying to take back that space and make waterways more natural and more beautiful. Why would people not want something to be more natural? This is being responsible — not just to what the city and people need, but to the environment’s needs. Birds. Fish. Trees that should be growing along these corridors. All these work in unison. If you break the chain, things fall off course.”
I appreciate some of the language, but the term “undoing history” is a bit strange to me as I always think of projects like this, in any form, as redoing history. I guess it’s your take on what is history: the original pre-development condition that needs to be restored, or the interventions and filling as the history that needs undoing. As mentioned, there’s plenty of history as “Historic Denver maps from the late 1800s show multiple irrigation canals and curving dotted lines denoting unnamed waterways, including a creek that flows through the Montclair Basin from Fairmount Cemetery toward north Denver industrial areas where smelting and rendering plants were located along the South Platte.”
Either way, it’s a cool project, and has some unique components and context, much of which can be found in the Denver Public Works ‘Green Infrastructure Implementation Strategy‘, a document broad interventions for stormwater and habitat. The prevalence of creeks is seen in the map of Recieving Waters (page 7) shows that while there are a number of urban creeks, they are impacted by residential, commercial, and industrial development throughout the region,
A series of maps in the report outlines pollutants of concern like Fecal bacteria and E.coli, Total Suspended Solids (TSS), Nitrogen, Phosphorous. This map (page 21) shows subbasin level designations of Nitrogen, which is elevated by human activity, and can lead to algae blooms, and issues with aquatic species.
A focus on the urban core includes the Platte to Park Hill (Part of area 20 above (City Park/Park Hill), which integrates a number of systems. As mentioned in the report: “Stormwater Systems is taking a comprehensive green infrastructure approach to better protecting people and property against fooding while improving water quality and enhancing public spaces. Four projects are part of the Platte to Park Hill… Collectively, the four coordinated projects will increase neighborhood connectively, add new park and recreation spaces, provide critical food protection, and improve water quality.” (page 54) The Globeville Landing Outfall project is one of these segments, as part of the strategy, using open channel design, which “…will help clean storm water naturally when possible and will move the water to its ultimate destination, the South Platte River.” A rendering of the plan:
The 39th Avenue Greenway (also seen in the header) also includes open channels for flood control and storm events. The opportunity to layer community function with these facilities is key, as they are “…designed using a community-focused approach to provide the following benefits in addition to flood protection… “ which includes new open space, bike/walking trails, and more. A rendering shows this integration.
An additional article from the Denver Channel provides a bit more perspective in video form on the Montclair Creek Project, including the “gray to green” approach “correcting past mistakes” focusing on the daylighted river weaving through a golf course and some more urban parts of the City, along with a greenway as mentioned above prior to outlet into the South Platte River. The funds for the project, which were not insubtantial at $300 million, were voter-approved, with “daylighting of old waterways that were forced into pipes and buried during the industrial revolution in favor or streets, railroads and homes.”
