This study presents an examination of conditions prevalent along the South Platte River in Colorado throughout the twelve mile stretch within the Denver metropolitan area, a strategic plan for the rehabilitation of the river, and illustrative design scenarios which address a variety of typological conditions found within the corridor.
As the study began, we discovered a story of a forgotten rive, a river whose natural character has been forsaken by industrial use and general neglect. We also uncovered a story of a city which was founded along the banks of a once life-giving river, but which is now virtually separated from its source. The river has not been recognized as a physical part of the city, nor is it seen as a meaningful component of the life of its inhabitants.
We would like to encourage the development of a symbiotic relationship between the river and the city wherein the river may be allowed to restore itself to an ecologically viable system and where the city could once again look to the river as a founding part, so that the process of reclamation from a physically abandoned and socially neglected area to an integrated city core may begin.
According to the 1990 US census, the areas adjacent to the Platte have the highest infant and youth population, the highest Native American and Hispanic population, the highest numer of female as head of household with children populatioin, the lowes percnetage of high school graduates,t he lowest income per household, and the lowest employment rate. According to the physical inventory of the same areas, the enviroment alon the Plattte has high levels of distrubances, noise and pollution,m low biodiversity, low degree of relationship with surrounding neighborhoods, low consideration as a place and an overall low quality that makes the river a dump instead of a core. The combination of social and physical issues gives complelling reasons for the development of a revitalization plan.
Physical Character and Natural Systems
River Form
The form and processes of the South Platte River drainage basin have changed greatly in the last 130 years. Early maps and reports show a meandering, braided river wtih banks up to a mile wide in places. Major changes in the river channel and in its tributaries are recordes as early as the mid-nineteenth century, when the first large migrations from the eastern United States began to settle the West.
Cotton wood associations along the South Platte and Cherry Creek were felled for lumber and firewood, exacerbating the intensity of the sun in a highly arid climate and disrupting the continuity of wildlife habitat. The flow of water ranged from a trickle to a torrent, causing flooding problems and making it difficult for early settlers to use the river as a consistent water supply. Control measure began almost immediately, and the stretch of river through the Denver area is now channeled with flows carefully controlled by the upstream dams and reservoirs. While useful to make a predictable regime for city purposes, the se changes have megative impact on river prerogatives. Water quality and wildlife habitat have been damaged and the aesthetic value almost deleted.
The concept of a two stage channel can be applies to mitigate some of the losses the Platte has suffered. Within the main channel of the waterway, a narrower, deeper channel with an alternating pool and riffle sequence, will accommodate the low/medium flow, so increasing water velocity, and re-establishing natural processed of scouring , erosion, depostion and oxygenation. The existing stabilized banks allow this inner channel to migrate to some degree in meanders proportionate to its width. Vegetation will be allowed to grow between the inner low/medium flow and the outer high flow channels contributing to wildlife habitat and diversity.
In areas wehre a tow stage channel is not desirable, meander can bne encouraged within the banks of the channel by creating an asymmetrical cross-section at potential bends. a 3:1 slope on the opposite bank will facilitate point-bar formation, emulating the natural process of meander establishemnt. In some areas of the South Platte, long-term planning could include the restoration of original meanders, beyond the current channel, possibly in combination with tow-stage channel design.
The gulches
Five small gulches are a significant part of the urban South Platte River system. In addition to being a natural drainage way in an artificial environment, the gulches may serve as corridors for wildlife and people.
By identifying the three functions of the gulches, the typical requirements for porposals could be outlined. Any proposal must safely and efficiently convey storm water from populated areas, provide sufficient vegetation in deffective patterns for wildlife movement, and provide a trail system to channel people through the city to the existing Platte River Trail. The general form for a typological design comes form the patterns recommended for effective wildlife corridors; linear progression of vegetation offering grass, shrub and tree layers; planting in patterns perpendicular to the corridor with sulpeted edges to aid birds in the identification of the greenway.
Restoring vegetation will mitigate some of the damage related to urban run-off and give the gulches an image more identifiable as a natural drainage system. This form may distinguish the gulch corridor as a unique space within the grid of the city, so that people far form the main branch might have a mental and physical connection to the river.
Wildlife
Primary goal of the intervention are to reconnect people and nature in an extremely disconnected system and to crate an environment that could be beneficial both for humans and woildlife. The river is aligned wit the annual North/South mirgatory route, and migratory birds and forest bird species crossing the grasslands use the South Platte for food and shelter. IN order to sustain this role of the river, the study identifies patches adjacent to and beyond the river to be connected between themselves and to the South Platte River corridor. These new corridors will combine with the existing tributaries of the Platte to reinforce the system.
Diverse and continuous vegetation along the greenways will build a network of alternative paths to and from the hills, the reservoirs, the countryside, to provide small mammals, small non-game birds, and waterfowl continuous habitat. Vegetation of different size will be planted at different stages to fill missing layers of trees or shrubs to maximize diversity, and in such patterns to attract birds (sculpted edges, peninsulas, perpendicular connections).
Fish
The quality of fish habitat is related to water temperature, amount of oxygen in the water and level of water flow. Currently the water of the South Platte is clean when leaving Waterton Canyon. As the river goes through the urban environment, the quality worsens.
While we urge state and federal agencies to implement stronger policies, procedures, and controls for wastes discharged into the river, we can implement remedies for some immediate mitigation: adding wetlands, meadow and catchments at inlets in the urban setting to aid in cleaning and settling pollutants out of the water before entering the river; shading the river by planting the banks to aid in cooling the water; meander and deepening the channel; creating riffles and pools which will add oxygen and provide feeding places for fish.
Wildflower Plantings
The banks of the river currently display a high level of disturbance. Erosion and trash piles scar the surface. To recreate entirely what was there before the settlers arrived is not a possibility. However we can establish a new image both aesthetically pleasing and environmentally sensitive.
the South Platte River corridor originally had an abundance of wildflowers interspersed with a variety of prairie bunch grasses. Many of these species are gone today because of the plowing of Buffalo Grass ( Buchloe dactlyoides) and Grama Grass (Chondrosum gracile) for development. These grasses helped prevent erosion and dust storms, and wildflowers grew best when combined with them. Replanting wildflowers and bunch grasses native to the area will improve the aesthetic experience by encouraging understanding of the natural history and processes of an ecosystem as in heightening awareness of seasonal change of colors and textures; will reduce maintenance costs; will promote biodiversity by attracting wildlife, contributing to better water quality and bank stabilization.
Seed stocks should be collected within a 100 mile radius of the river where desirable species are growing in similar condition. Micrositing and both mechanical and chemical protections will be necessary. Mycorrhizal inoculation is key to the plants survival and their ability ot filter phosphates and heavy metals. A mutualistic symbiosis between roots and fungi will help alleviate drought stress, stabilize soil and reduce transplant shock. All wildflowers must have a good germination potential and a physical purity which will help cover banks quickly. As plants mature, they will provide seed stock for further implementation, Careful timing of mowing is important to insure re-germination.
Planting in this developed contest will be thought of as integration rather than imitation. As in the Texas roadside planting program on seventy thousand miles of highways, where landscapes are not natural but planted, and still became scenic attractions for botanists, painter and photographers from around the world.
Wildflower planting will be especially concentrated in highly visible areas for people to see it and take notice, defining places of interest and access to the water; areas around bridges, heavily used sections of the bike path as well as neighborhood connections. They will provide transition between formally maintained landscapes and relatively unmanaged areas. Plants with seasonal character and bright colors will be primarily used according to sequences of color schemes. The powerful scent of some of the wildflowers, which in some stretches will replace disagreeable odors from nearby industries, will contribute to the overall sense of place.
The urban interface
The line and the grid.
Urban rivers thoughout the world cut through an incredible variety of city organizations. In the case of American cities this is often the Jeffersonian grid established during the westward expansion. Observation of the relationship betweeen the city grid of Denver and the natural path of the South Platte River shows that the river has been signifficantly altered in order to adapt to the city grid, but also that in some cases the city grid has been influenced by the presence of the river’s path. The lack of definition of the space along the river creates a tear that breaks the city in two, rather than creating a place that embraces the two banks. Several maps were overlaid for the observation of the city-river relationship; the historic map of the area in 1862, the flood plain map, the street map, the zoning map.
The combination of these maps brings several considerations. The pre-settlement map shows the river in a meandering form, a large flood plain within sloping banks, and the lines of the Jeffersonian grid preparing for the inhabitation of the land. The new map shows the overpowering presence of the city grid. Ther river has been straightened in to a narrower corridor whose scale disappears against the streets. The flood palin has much more width variation than the void space of the corridor would suggest; the edges in most cases extend beyond the grid’s edges. The prevalent use of the corridor is currently industrial. While in the past there were practical reasons for this choice, there are no reasons now to occupy this unique area for land uses not associated with it.
A new map was developed to visualize where the structure of the city grid ends towards the direction of the river. This proximity map groups areas where the edge of the city grid is close to the river (0’-800’), at mid-range (800’-2000’)) and far from the river (2000’+). The space within these lines is a mix of amorphic associations of buildings and areas of empty space.
Three situations exist. Where the city is far from the river, the South Platte still keeps some of its identity. In these locations we propose to bring th eriver back to its meandering form and use adjacent land to spread the character of the corridor. Where the city is very close to the river, the South Platte is practically swallowed by the dominant presence of the city. These locations may offer to the city that borders them an urban riverfront, especially oriented for pedestrian use. In the intermediate range, specific site conditions will determine whether to extend the natural attributes of the river or to incorporate the city form around it. In all of the three conditions designs are to address both systems.
The river and the evolution of the city form.
The physical landscape of the area has been primarily shaped by the South Platte River and its tributaries, which have carved riverbeds into the soft alluvial fan along the eastern edge of the front range. The city’s urban structure may be described as consisting of four layers. The first layer is the physical landscape of the South Platte River and the gulches and creeks that are its tributaries. The second layer is the movement corridor, made of the early trails, roads and railways, and canals and ditches. The third layer is the American grid system of streets, blocks and lots. The fourth layer, which has its origin at the time of the “Denver City Beautiful” movement, adds on the parks and parkways systems developed during the first decades of the twentieth century.
Native Americans, Pioneers and Industrial Era
“The Moonshell is, for the most part, a quiet river, an unobtrusive river. It is not deep, nor fast, nore useful for navigation. It does not transform the countryside through which it flows, but nestles gently into it; a partner wit the land rather than a destroyer.” This is a description given by the Native Americans who lived beside the South Platte River. These Plains Indians saw the river as a center point in their life rhythms. They occupied the banks for their seasonal settlements and corn farming.
The first pioneers saw the river much differently. The river was referred to as the “finest natural highway in the world.” Pioneers crossing the plains used the south Platte as a natral pathway in which water was always available and the path was always sure. With the development of permanent settlement, agriculture on the river banks became a significant activity and had its focus at the Denargo Market where Denver and the small town of Argo shared a common boundary. The farmers were Italian immigrants who relied on the rich soil of the flood plain for orchards and crops such as sweet basil, garlic, beans of all types, onions, cabbage and grapes. These crops were originally sold locally by the farmers themselves through the residential neighborhoods. During the first year of operation at Denargo, five hundred growers and sellers were present daily to sell their produce.
As the settlement grew, the north and west boundaries of the original towns of Denver, Auraria, and Highland were shaped by the banks of the South Platte. The main circulation corridors, the interstates, Highway 285, Santa Fe Drive and Speer Boulevard followed the easiest way along the flood plain banks of the river and its tributaries. The rest of the city, following the American grid, was by nature at odds with the meanders fo the Platte. The grid expanded to obliterate the South Platte as the spinal organizing element of the city.
The river was then still present as the non-visible support system for the city green system providing recreation and relief from the urban environment. Through the diversion of the Platte River water into the artificial waterway of City Ditch, the arid landscape was transformed into an environment able to support plants and crops native to regions far more temperate than Colorado’s front range. City Park, Washington Park, Cherry Hills Golf Course, Denver Country Club, and several tree lined streets were made possible by irrigation with river water captured in the Ditch.
As we design for Denver and the river we must consider the role of the river in the development of the modern era, and include in the narrative the artifacts of this industrial heritage. Starting at the southernmost end of the river as it enters Denver, is the Robinson Brick Company, one of Denver’s oldest “manufactories”. Because of the shortage of lumber in this region, brick is Denver’s most important building material. Denver is in fact often referred to as the Brick City. Robinson Brick owns 50 acres on this site and manufactures two million bricks daily. Its bricks have been used for many of Denver’s historical buildings as well as for the modern Coors Field arena.
The next point of industrial history along the river, just east of the Confluence and hovering over Cherry Creek, is the Ady and Crowe grain elevator, constructed of wood and brick and believed to be the only one of its kind in Denver. It was built in 1910, with various additions and repairs made until 1946.
Next to the grain elevator are five train trestles, three of which are abandoned. These are relics of Denver’s possibly most important industry, the railroad. It was because the Platte River Valley afforded a wide and relatively easy area for track construction that Denver became the financial and commercial trading center of the West, and so to this day, train tracks are a significant presence along the banks.
Another significant presence is perhaps Denver’s quintessential trade, the cattle industry. During the mid to late 18 th century the Denver Union Stockyards thrived, especially after the railroads located here providing market alternatives to the long and arduous cattle drives that were previously used to move cattle to Denver. The stockyards moved to this site in 1880 and remained here until 1971. Many of the original pens and offices are still in place.
In the proposed designs, the artifacts containing these four of Denver’s “heritage industries”, are returned to educational and recreational activities for Denver’s inhabitants and visitors.
Awareness of the River
The South Platte is nowadays still visible looking at maps of the city. Yet it is not looking from within the city. Increasing public awareness of the rive is then at the basis of every intervention. Different sets of actions are to be taken inside the channel and outside the channel.
At the city scale educational programs in conjunction with city museums, parks, and schools will introduce the South Platte to people, while physical and mental connections will be developed. In areas in proximity of the river, designs will create visual sequences, open views to the river, refer to its presence in bridges, plan observation areas, etc. Within the channel, the subtlety of educational awareness by means of design without use of traditional signage was considered. Designs are developed to increase awareness of seasonality, speed, changing width and levelof the water, sound, associations of plants and other episodes.
Through community participation we can answer to the question of what do we want to see in the designs about the river; geologic and cultural history, water hydrology, pollution, how the river has been used for food, transportation, recreation, a garbage dump, source of income via minin, etc. Finally, what the river menas ot usin terms of sound, smell, movement, cooling, a boundary to cross, a peaceful place for retrospection, a landmark in the prairie, etc.
Visual Disturbances
As a society we have designed and planned American cities under the illusion that infrastructure should be separated from the landscapes that nurture us spiritually and economically. Visual tension is generated when infrastructures occur in unexpected settings.
This is evident in several places along the Platte which are used for electricity generation or water treatement, including the Arapaho and the now vacant Northside treatment plants; the Arapaho and Zuni power plants; and several smaller electric substations. Other examples are industrial stretches of manufacturing plants and warehouses. The fact that these types of sites are also surrounded by acres of vacant land walled off from human contact compounds the perceptual problem. We tend to read these sites as visual disturbances, and not to consider thei critical functional or historical connection to the Platte. The result has been a disconnection from vital processes that sustain us and a disownership of the built structures that house them as “blights upon the landscape.” Because the forms of these structures do no often reveal the processes occurring within, they are hard to understand and appreciate.
Other cities have renetly taken a new approach to infrastructure, using ecological features, functions and character of the landscape to incorporate these processing systems into the landscape. The city of Phoenix, for example, has begun to redevelop and strengthen its infrastructure while at the same time transforming these public works into landmarks that help both visitors and residents locate themselves within that city’s sprawling urban landscape. This approach has resulted in the transformation of a cross-town expressway into a parkway planted with native desert vegetation; a highway overpass transformed into a community gateway; and a garbage transfer station which has become a public landmark and environmental education center. Infrastructure is now a part of citizen’s mental map, cognitive landscapes that help define the place in which they live.
Other experiments have worked with large areas of vacant land surrounding public works complexes. Landscape architect Richard Haag suggested a different perception of industrial artifacts in Gas Work Park in Seattle, WA. In Byxbee Park, recently completed in Palo Alto, CA, landscape architect George Hargreaves carves out thirty acres of urban refuge in the middle of an airport, antenna fields and a still active landfill. Abstracting both natural and cultural forces (underground garage, nearby landing fields, prevailing winds) he creates a sense of place from what was once an eyesore.
Drawing upon these recent precedents, illustrative design schemes have been proposed to transform vacant land surrounding various public works and industrial sites along the South Platte River into productive spaces that reveal their function as well as serve as landmarks for way finding along the river. Three prototypes have been developed.
The power plant typology is derived from condition at the Arapaho and Zuni electric plants: the transformer grid; the sue of steam to generate power; and the large cooling ponds that hold water before it can be safely released into the Platte. An illustrative design is developed for the Zuni site with abstracts these features and transforms surrounding space into an educational park.
The water treatment typology derives form conditions at the Arapaho and Northside treatment plants, drawing on the form and arrangements fo containers for filtering and treating water. The illustrative design for the Arapaho site, presented in the master plan, develops a sequence of hydroponic gardens that utilizes these concepts and forms.
Last, the industrial typology speaks to the idea of mass production and repetiion inherent in manufacturing and warehousing. In both industries the building form, repetitive massing and simple façade, reflects processes within. The illustrative design for the vacant area near the Gates Rubber plant shows a sequence of detention ponds to gather storm water. The ponds are lined with recycled rubber and when dry can be used for skateboards and other sports.
All the interventions are to be founded on a comprehensive framework that includes the different issues, goes though the cycles of developing solutions and checking them against each other to deepen knowledge of the system and to heighten the appropriateness of the actions.