Last week, I had the honor recently of presenting at a conference with one of my idols of landscape architecture, Anne Whiston Spirn. Aside from stimulating conversation, she presented the old and new of her work from The Granite Garden through her ongoing work on the Mill Creek Project in Philadelphia, i was reminded of the tenets of persistence and the need to not work behind the scenes, but to continue to strive outwardly to make ecologically driven, research based, green and livable cities. As many know that is inspired in me through work with water and watersheds, but also storytelling and ways to make evident that which is lost or merely hidden. That inspiration comes many sources, but very much from the work of Ms. Spirn.
To capture my work and continue it in some form – i transferred some posts from the early days of my firm back in 2010 that formed the foundation of an ongoing work that is gaining more momentum in recent weeks, and worthy of a dusting off. Partially as the blog is an archive of work and things i want to capture and remember – partially it is an opportunity to rework and re-frame these issues in a new time with some new energy. Some folks will have seen this before in various forms – to others this might be new. Over the next few days, i will repost some of the inspirations, starting today with the introduction – followed by some origins gleaned from others through the readings and explorations. In all, it the various threads of this perpetually wandering generalist may be coming together to form a web, and with luck and work, a tapestry.
Hidden Hydrology – Portland Series Introduction
Originally published on Terra Fluxus – 12/21/2010
In the next year, TERRA.fluxus will be initiating a multi-phase project to explore the Hidden Hydrology of the city of Portland as the main research activity for the near future. I have been fascinated with this since my first glimpse of the Disappeared Streams map published by Metro (will get my hands on one soon and give a glimpse) and it’s eventual configuration into a 2006 ASLA Presentation on ‘Neighborsheds for Stormwater Management‘ as an preliminary exploration of the concept. The particular Metro map highlighted ‘historic’ streams that had been buried and piped through development of the City of Portland over the course of the last 150 plus years, showing existing as blue and those ‘disappeared’ in red. While many westside creeks still ran free, the entire eastside was vivid red, long covered by roads, industrial buildings, houses, parks, and more. While the methodology on that particular map was suspect (relying more on topographic analysis than hydrological markers), there are plenty of sources for historic waterways in maps, photos, and on-site investigation.
Thus the focus of the project, utilizing multiple sources to gain a more complete understanding of the underlying hydrological history of the area, with an aim towards using this information both in traditional planning and design manners, but also as the touchstone for a series of speculative works.
Portland, of course, has always been, and still is, a river city. We live around waterways and bridge lifts, and relying on water for our recreation and port traffic, as well as giving us the overall image of our city. Tucked along the banks of the Willamette and its confluence with the Columbia, the history of water mirrors the history of urbanization, from the initial settlement patterns and grids of the 1850s up to modern conditions. The early, or ‘pre-development’ snapshot is best captured in this compilation map of the 1852 Cadastral Survey, which was created right after the incorporation of Portland as a city in 1851. This map, and others (a great collection of which can be found at the Bureau of Environmental Services site), will play parts in analysis throughout the project.
You can spend hours looking at this map, and placing the vision of this early city compared to it’s eventual form. While Portland’s rivers and streams are beautiful – they are also highly troubled, with dual issues of industrial pollution and combined sewer overflows working in tandem to create issues for native fish (and people), landing many of our major waterways on lists of the most polluted rivers. The idea of hidden hydrology is evident not in the still visible (although they are intimately connected), but those ‘urban’ waterways that over the years have changed from open streams and creeks to become piped as ‘infrastructure systems’ to deal with expanding growth of the metropolis. Thus we look at the slow erasure of natural topography and hydrology at work in a political sphere, and begin to see what remains of this palimpsest.
The most urban example is found in Tanner Creek, the historic downtown river that wound through downtown for over fifty years, remaining intact (in form if not in quality) through urbanization, as seen in this 1881 illustration looking at downtown towards the northeast.
The proximity of this creek to development (and the Tannery) led to pollution and sanitation issues downstream, so as with many urban creeks, a period of modernization happened, in this case the 1917 implementation of the Tanner Creek Sewer project. This forever buried the main stem of this historic creek through the heart of downtown in brick vault sewer (many of which are still functioning, or have recently been replaced).
:: images via Bureau of Environmental Services
While the historic are interesting in their own right (and there are ample sources of material to digest so more to come on this), the interaction of the new and old is both dynamic and informative. Moving to the Southeast Quadrant, we can isolate the more detailed Cadastral maps (the survey developed the township, section geometry used today, thus giving us the ability to overlay old and new with a measure of precision). The coverage through the 1850s and 60s is quite extensive, and will be useful when reconciled with the existing GIS coordinate systems. An inverted version of the original survey maps gives an indication of their density of information. The study area will be in the upper right hand quadrant of this township scale map.
A series of maps utilize GIS layering along with historical mapping underlayment to create a modern ‘routing’ for a stream in the lower Taggart basin. First a section of the historical map (1852) was analyzed for hydrologic features (river, stream, wetland, etc.) based on the map features present at the time of the survey. These are accented to show their location for referencing to other maps.
The topography and street grid are overlaid to show the relationship of water features to current configurations. The addition of hillshade allows for fine-tuning of hydrological features to match remnant topographic that has not been leveled or erased through development.
Following this, the combined ‘hybrid’ map is reconciled into a workable base that is accurate to the historical location of ‘urban streams’ as well as current urban form. Additional layers are added, and the iterations of analyses are only limited by time and usefulness. Groundwater, soils, historical aerial photos, vacant lands, floodplains, and vegetative cover are just a few that spring to mind from glancing at Metro’s stock of layers. I am also already other gathering data for a planned comparison with BES Subwatersheds, which mirror directly the configuration of subsurface pipe infrastructure that replaced these open channels sometime in the last 100+ years. While our technology allows us to perform feats unbelievable to the 19th century Portander in lifting, pumping, and moving materials, there is still an inherent consistency and efficiency of using gravity to move water and waste that still makes these historic systems relevant as blueprints for existing conditions.
The other idea is to use this information for potential projects and interventions – looking opportunistically at the relationship of these systems over time and space. To kick of this aspect, the next phase of analysis for this area will also be to ‘ground-truth’ the map hybrids – through a series of documented urban explorations (in the spirit of the Center for Land Use Interpretation perhaps?), along with further refinement, historical research, and analysis throughout 2011.
Stay tuned for more info after the new year.