Los Ángeles: Los espacios del agua en el territorio urbanizado
LOS ÁNGELES: AQUATIC DYNAMICS WITHIN THE URBAN SPACE
Los Angeles water and energy infrastructures that link the city with the surrounding landscape are the largest in size in the United States. As technical tentacles, these lines connect the city with far away territories: big dams in Arizona and Nevada, aqueducts longer than 700km towards the north and east, gas pipelines, power stations and other energy supplies like the Pacific Intertie that delivers electricity along 1362km of the west coast, from Washington to the Los Angeles area. This network makes a contemporary metropolis with more than 10 million inhabitants possible.
1. LANDSCAPE CONSTRUCTION AS CULTURAL IDENTITY
Settlements in the west of the USA during 19th and 20th centuries have utilized a landscape model borrowed from Europe and consolidated on the east coast. Relationships with land and nature during the process are extraordinarily valuable as references for national identity. The 100th Meridian divides the continent in two different and opposite areas: a humid East, with more than 500mm of precipitation, and the arid West with less, and in need of irrigation to survive. A geometric grid that organizes either land or cities, deserts and wetlands defining economic and politic jurisdictions, requires the existence of major public works to enable its growth in the arid lands and the establishment of civilization in the desert. On an urban scale, the same idea leads to an exciting experiment of low density and large surface garden city in Los Angeles County.
In this context of scarcity, water management has determined wealth and development levels at the same time as urban form. Water supply systems have been essential to american industry and civilization. During the second half of the 19th century, mining in California required building large water infrastructures. The realization that water, as a resource, was valuable to the mining and other industries changed the mentality of the players. Following the industrial growth, this water was then delivered to the cities and became integrated into the infrastructure. Almost all rivers and water courses are modified or dammed and water is diverted from one ecosystems to another. Reservoirs and water ways can be found in very arid landscapes, where rain evaporates before reaching ground surface, or disappears immediately in a complete dry soil. At present 80% of fresh water in California is used for desert irrigation while at urban scale, 39% of water in Los Angeles city goes to the maintenance of grass lawns and exotic plants.
2. PHYSICAL CONTEXT
Los Angeles landscape morphology results from tectonic activity and climate regime that accomplish most of the geomorphic work. Mediterranean climate winds and water are powerful agents that shape the land through high intensity and low frequency events. Rainwater movement, from mountain ranges to the Pacific Ocean has formed alluvial fans and flood plains where a big residential and industrial area has grown. Geological composition of these soils, with high permeability, lets water percolate in underground basins. Petroleum reservoirs that have enabled economic development and are the reason for so many holes drilled into its deep subsurface can also be found.
Recent history shows a surprisingly high amount of disasters: droughts, fires, earthquakes, landslides and debris flows that tend to be organized in powerfully coupled causal chains. Research made by Mike Davis suggests that many of them in the last decades were avoidable and a result of transgression of environmental common sense made by market-driven urbanization.
Deep interaction between economic factors and productive activity on one hand, and the LA biophysical ecosystem on the other has been long studied, due to the fascinating complexity of this urban nature. At the beginning of the 70s, Reyner Banham established 4 ecologies to make metropolitan life understandable: beaches, hills, plains and highways.
Urban hydrology is the result of overlapping existing stream networks and urban patterns. Previous watershed is transformed into an architectural/infrastructural watershed with its own limits. Topography´s determinant influence is modified and adjusted by other parameters, as treatment plants and outlet locations, defining the pipe network that shapes watersheds and sewersheds. Higher density urban areas are located over Los Angeles River, San Gabriel River, and Ballona creek y Dominguez channel watersheds.
3. AQUEDUCTS: INFRASTRUCTURAL WATERSHED
Aqueducts reshape connections between city, landscape and geography. Building three linear systems for diverting water from different areas of California and other states to Los Angeles has transformed the previous local watershed.
These abstract blue lines go through crop patterns as well as through the enormous extension of empty and amazing eerie landscapes, searching for the right slope for water flow. Pumping stations, reservoirs, siphons along their length manifest internal organization laws related to precision and technology. Contrast between surrounding aridity and enormous water bodies reveal a surprising artificiality. Such gigantic size gives them a real monumental and sublime character. This entanglement of nature and construction forms the Los Angeles county´s operating watershed.
The Los Angeles Aqueduct, built in 1913, delivers water from Owens River in Sierra Nevada, California, along 359km and two hydroelectric power stations. It works by gravity only and produces energy by water flow. In 1940 a second branch extended the first aqueduct to the north and in 1970 a whole second line, that though shorter, requires pumping.
The Colorado River Aqueduct, built in 1941, delivers water from Lake Havasu in Arizona, along 390km. It raises water over 492m high by means of 5 pumping stations. The Hoover Dam construction near Las Vegas built in 1936, upstream in the Colorado River, starts a process of water delivery and modifies the river´s natural flooding seasons. Hoover Dam was the biggest dam in the world for decades. Together with other engineering public works it has transformed the ideas of monumentality and public space in the American West, and at the same time it has made possible the development of an urban landscape based on private gardens.
The California Aqueduct belongs to State Water Project, and takes water from San Joaquin and Sacramento rivers in northern California and delivers it along 714 km and 5 pumping stations for crop irrigation in the Central Valley and water delivery for Los Angeles city. Most of its length is an open concrete channel, with trapezoidal section and an average depth of 9m.
Water consumption has been reduced during the last two decades, from 653 liters per person per day in 1990 till 442 at present, but it still remains one of the highest in the world. With a future scenario of growing population, there are legal restrictions to the amount of water that aqueducts are diverting from other ecosystems as a result of ecological damage and conflicts over water rights. Expected climate change will also reduce precipitation and snowpack, higher temperatures will increase evaporation and earlier snowmelt, as well as varying the climate and altering rain patterns to less frequent, less predictable and more torrential. These monumental public works are having a difficult time assuring an ever scarcer water supply.
Such long distances and the transportation of water over high mountain ranges definitely link water supply with energy consumption in California. This is one of the main problems that within a context of growing energy prices, leads to reconsidering the relationship between water and territory. Drinking water and wastewater treatment and delivery account for 7% of California’s electricity demand. Water systems comprise ~56% of a California city’s total energy use. In Southern California, almost 70% of the energy needs of urban water systems stem from the supply of water. With absolute numbers, water conveyed the entire length of the State Water Project consumed 6,034 GWh of electricity in 2001.
4. ENTROPHY AND ISOLATION. LANDSCAPES IN UPPER WATERSHED
Urban landscape construction corresponds with entropic processes in other ecosystems. Through extension of city´s ecologic frontier, the urbanization of nature and city naturalization are linked phenomena.
To enable such a fascinating experiment of extensive private garden, big surfaces have inverted their working and evolution, losing the necessary water to survive. Massive land purchase in upstream territories has been necessary to acquire water rights in order to preserve water quality and avoid any operation that could provoke pollution. These measures have completely stopped any possible development.
The extension of these surfaces and the control strength are related to chemical and filtration treatments in city plants.
Owens Lake is now a 250km2 dry beach formed by sand, alkali and mud dunes covered with salt, that originate toxic dust storms. A long process in the Supreme Court finished in 1998, changing the trend and introducing mitigation efforts. Sprinklers with fiber-optically controlled valves have been installed to reduce dust emissions in the lake and recover shorebird habitat. Underground water extraction has lowered water table level, now far away from local plants´ roots. The speed of this process has made it impossible for vegetation to adapt to new conditions and colonize exposed surfaces, nor new alluvial sediments to neutralize the salt layer, which in this soil contains arsenic and selenium. The dryness of the Aral Sea in the old USSR is a similar ecologic disaster. The surface of Owens Lake has acquired intense colors because of the presence of halobacterias that turn water and salt bright red. Algae sometimes stain the water with green color too. Energy transfers and entropy processes relate private gardens in Los Angeles with this ecosystem of salinity soil and dust storms.
There is a great opportunity for dust control infrastructure to initiate the cultural shift from parasitic exploitation of resources and territory, to being an agent of mutuality for rural regions (not just the generator of urban conditions).
Owens Lake. Great Basin Unified Air Pollution Control District http://www.gbuapcd.org
Colorado River water, during its way through the desert is diverted to irrigate farming communities. “When water percolates in the soil and returns to the river, it goes through thick mineral salt deposits, easy to find in the arid west. During the irrigation season, temperatures in the desert oscillate around 40ºC, water evaporates as if heaven was a sponge” increasing soil salinity with every irrigation. In the River´s delta in Mexico, 95% of wetlands have disappeared and the estuary has been salinized. System failure and alternative conveyance of floods in 1905 gave rise to a reverse situation that ended with the Salton Sea formation in Imperial Valley. Water presence has changed local ecosystem evolution, with many new species of fauna and flora. Water increases its salinity due to high evaporation rates and industrial and agricultural sewage dumping.
California aqueduct diverts 70% of fresh water from a complex and delicate ecosystem of the San Joaquin and Sacramento delta near San Francisco. Several channels and dams have altered the natural water drainage, with the result that the water table and soil levels have sunk in the San Joaquin valley. Reduction of flow and sewage dumping are threatening the quality of water supply at the southern area of the delta. Irrigation of croplands in the Central Valley with state water project is also increasing ground salinity, exhausting its production capacity- The changes in water use caused by the Hoover Dam’s construction has had a large impact on the Colorado River Delta. The construction of the dam has been credited with causing the decline of this estuarine ecosystem. For six years, after the construction of the dam and while Lake Mead filled, virtually no water reached the mouth of the river. The Colorado River had experienced natural flooding before the construction of the Hoover Dam. The dam eliminated it, which imperiled many species adapted to the flooding, including both plants and animals.
So many environmental disasters, that are damaging upstream ecosystems and water quality, have caused the reduction of water intake to the aqueducts, thus lowering levels below their nominal capacity. Soil salinity, aquifer depletion and progressive sedimentary accumulation in dams and reservoirs are problems with unknown solutions for the time being, that reveal hydraulic infrastructures´ vulnerability . Systems based in big works, that modify in a radical way the normal running and equilibrium of arid ecosystems have an uncertain future.
5. URBAN CHANNELS
Rivers in Los Angeles go through one of the most complex urban watersheds. With more than half of its surface covered with buildings, open space and forests are located at the northern area, close to the San Gabriel Mountains. Before the channels´ construction, form and flow of water were variable and unpredictable, flooding extensive areas. As a seasonal stream, it was formed by run off from torrential rain in the mountains, and during droughts the water came from springs. Nowadays water table levels are drastically reduced, and surface imperviousness has reduced natural percolation and aquifer recharge. Until the completion of the first aqueduct in 1913, rivers and aquifers were the only source of fresh water for the city.
Construction of a complex systems of concrete channels by the Army Corps of Engineers as a flood control system from 1935 on, radically transformed its running and character, establishing an intricate relationship with other urban infrastructures.
San Gabriel River. Imagen satélite Nasa.
The Los Angeles river channel is the largest public works in California after the Hoover Dam. Aerial photographs show its intense infrastructural character. Along its way through city´s surface, its form is narrow, soft and precise. Its designed curves and precise lines are moving softly and rhythmically in a controlled trajectory, increasing its dimension as it finds its tributaries in an elegant confluence. This very efficient mathematical geometry, has transformed rivers into a stormwater drainage channel system, that are part of a complex device for water flow control, that release water in a coordinated way as it is managed by the system.
Last century changing conditions have modified water source. Natural flooding plains have been built. Treated sewage is the main source of its small stable flow. Thousands of drainage overflows finish in the channels, adding urban runoff from irrigation and street cleaning with pollution and waste. During storm events, channel section is completely full, and comes back to its normal flow only 16 hours later, delivering water immediately to the ocean. A small part comes from polluted aquifers
10m below street level, the Los Angeles River has no urban presence, however it is a publically owned corridor that channels stormwater and sewage, as well as movements of trains and cars, electricity and waste along 80km to Long Beach Harbor. Despite this artificiality and the change in water sources, rivers continue being the spine of watersheds.
Its value as a living system as described by David Fletcher “contains a vibrant mixture of ecologies, vegetable, animal and human. It certainly doesn’t agree with arcadian ideals of a pure and bucolic nature. Nevertheless it is an infrastructural ecology, opportunistic and emergent, that feeds on human excess. We need to elaborate new narratives to understand and appreciate urban watersheds and how they work…better than bucolic, freakology is the key to understanding the current river. As a combination of nature and infrastructure, redefining the watershed, Los Angeles river is the most intense space in Southern California” as a device for flood control, it manages not only water but also debris and enormous amounts of sediments from tributary watersheds, dams and reservoirs. “Urban waste is a threatening for ecology, it has turned into an essential component of riparian ecosystems; debris has been incorporated into the vegetative community, forming a structural substrate that fixes organic nutrients and “. Winter storms carry all sediments out from river channels except big rocks, removing all the material necessary for life
Water dynamics imprint big scale marks in the landscape, within the endless pattern of dwellings and private lawns, introducing spaces with other size and character, whose natural value makes them attractive for public leisure programs
Water reservoirs are located depending on topography, where concave geometries and potential energy can work together with filtration plants and later urban delivery. Open reservoirs assure supply and coordinate entering volumes with current demand .
Attempts to stabilize the natural working of the ecosystem requires an enormous effort to control water movement and all the sediments that it carries with it. Geological composition with soft sedimentary rocks and non-cohesive soils, with slopes over 60% in 2/3 of forest area mean landslides and avalanche risks. Southern California presents one of the highest erosion rates in the world. Constant fire risk makes the situation worse, as it destroys vegetation that contributes to the stabilization and turns soil hydrophobic. Breaking sprawl rectangular patterns, urban dams appear as big slopes with enveloping curve forms. Its interior is a flooding area with ephemeral leisure programs related to greenery. Outside buildings fill the flood plain along the waters course. Sediments that should consolidate soils and river estuaries are now stored inside dams, reducing their capacity and modifying natural processes of geomorphic work.it is expected to deal with 66hm3 by mechanical extraction during the next 20 years. Areas currently available for debris gathering have a capacity for 8,8hm3, and for that reason ground surface profiles should be somehow reorganized, modifying their geometry. All kinds of solutions have been considered to solve erosion and non-stop sediment accumulation: withdrawal by channeling or pipes, train or truck transportation, and delivery to landfills, to consolidate beaches, or to refill quarry excavations. The search for options is directed at reintroducing natural-like processes and considering these sediments, as well as stormwater, as urban assets
Spreading grounds are shallow water surfaces built in permeable and non-polluted soils next to river channels, to improve deep percolation and aquifer replenishment. Different types of dams divert water from concrete channels to the spreading grounds, shaping an amazing aquatic landscape. Soil filtration seems to be enough for purifying water pollutants, as no change in underground water quality can be observed.
In such a homogeneous and uniform urban context, built with no typological diversity, infrastructures and productive surfaces have special relevance, contributing to increasing legibility and improving spacial quality. The role of highway systems in the image and understanding of the city is a reference to show the possibilities of these big scale landmarks based on their geometry, size and character. Providing them with visibility and accessibility, both important qualities of public spaces, could transform them into an essential part of the city´s spatial heritage.
Santa Fe Dam en el curso de San Gabriel River y láminas de infiltración
7. SYSTEM OUTLETS AND CLOSING THE CYCLE.
Rains are variable, seasonal and torrential, as already stated above, and such conditions make water management more difficult, with sporadic high peaks. Surface concrete channels and underground drainage pipes have replaced the existing stream network. In this way water becomes invisible, and follows a similar but geometrized way, established by the street grid. Influence of topography in the drainage basin and in water flow direction is very important. However outlets are different and network drainage takes distance from ground surface, adopting its own geometry of concavities.
Urban runoff that now disappears through this network is an important local source of water and humidity. In a future scenario of growing population and water scarcity, retaining as much water as possible into the ecosystem is, with flood control the main objective, related to water in Los Angeles. Changes in urban morphology are required for this purpose, to establish different relationships with performative capacities. Increasing water´s presence in urban spaces unleashes ecologic, programmatic and social phenomena
Re-use and infiltration
Hydrologic conditions make infiltration easier than other types of re-use. As a result of climate change, using recycled water to recharge groundwater supplies is a subject of increasing interest. Groundwater basins and aquifers have the potential to store significant amounts of water from a variety of sources, potentially including stormwater and treated wastewater for later recovery. . The opportunity to use the ground as storage avoids the inconvenience of building big and expensive tanks, and the need for a place dedicated to it.
Currently, wastewater that is used for groundwater recharge is subject to tertiary treatment with disinfection and in some cases microfiltration or reverse osmosis before being discharged for infiltration or injection. Public concern about mixing recycled water with groundwater appears to be partly alleviated by the knowledge that infiltration, percolation, and underground residence time exposes the water to natural cleansing processes. Presently, California has not approved direct potable re-use projects, that is, where recycled water is piped directly from a treatment plant into a drinking water supply. Due to rain distribution patterns, infiltration projects can be located anywhere in the city, considering soil permeability and pollution.
1. linear projects: green streets
“Green streets” are linear systems of run off management for residential neighborhoods prone to flooding, that include permeable paving and soil construction in linear branches of streets, pedestrian paths, parking lots and other esplanades. Small modifications of slopes convey water flow to bioswales, trenches and biofilters. Subsurface design includes infiltration galleries, and climate-adapted native vegetation is also used. Stormwater drainage is driven to these small retention areas to improve ground percolation before it can reach the pipe network. The performance of these streets is not visible but through landscaping transformation. Grass lawns disappear to give way to native and Mediterranean planting.
Elmer Street Avenue is the first of this kind of project, finished in May 2010. It manages run off from 40 acres of chronic flooding problems in the San Fernando Valley. The demonstration project is being monitored to evaluate surface water quality improvements, quantify groundwater recharge, water conserved on landscapes, changes in property values, and other benefits.
The maintenance and care of their new landscapes is the principal difficulty for increasing results
Woodman Avenue Stormwater Capture Project, also in San Fernando Valley works in a similar way. It would capture run off from a surrounding area of 130 acres. The project will build several sidewalk and median improvements, including a vegetated infiltration swale and underground pre-treatment and retention/infiltration systems, along Woodman Avenue. The proposed improvements, which are expected to be completed in November 2012, will capture runoff from a surrounding area of approximately 130 acres and serve as a demonstration project to illustrate innovative techniques and emerging technologies on stormwater capture and recharge.
2. linear systems: salt water barriers
Fresh water infiltration in wells forming a coastal barrier is a special case of linear infiltration solution. The water table in the west coast basin has been lowered due to excessive extraction and as a result, salt water pressure has increased, and enters into fresh water basins deteriorating water quality.
The West Coast Basin Barrier consists of a line of 153 injection wells from the Palos Verdes Hills north to the Los Angeles International Airport, a distance of approximately nine miles. A combination of recycled and imported water is injected into The 200-Foot Sand, The Silverado, and The Lower San Pedro Aquifers. Complementing the injection wells are 296 observation wells. They serve as key indicators of system performance. The observation wells are either internodal wells placed between injection wells or located off the immediate barrier alignment. The wells are used to monitor water surface elevations and depth specific chloride levels.
Alignment of the barrier was selected on the basis of geology, hydrology, and availability of rights-of-way. These factors resulted in the selection of Prospect Avenue as a suitable south -to-north alignment through Torrance, Redondo Beach, and Hermosa Beach. The alignment then jogs towards the coastline to connect to the original test project along the Santa Fe Railroad right-of-way in Hermosa Beach.
Imported water is supplied to the barrier at the terminal metering location. Downstream of this connection, the water flow splits between the City of El Segundo’s water system and the barrier project. Downstream of a backflow preventer, reclaim water is supplied by the West Basin Municipal Water District. Secondary effluent is pumped from the Hyperion Plant to the West Basin Water Recycling Plant Title 22 and Barrier Treatment Facility and then on to the barrier pipeline transmission system.
3. vacant public spaces
Other kind of projects introduce different relationships between public spaces and stormwater management, interrupting existing drainage pipe networks where possible, and transforming lines into ponds and wetlands, that bring small treatment and infiltration solutions distributed throughout the city. Decompression of water flow and multiplication of possibilities of reclamation and landscaping improvement through topography modeling, activate natural processes and space quality.
The importance of these projects is demonstrating small scale capacity for solving problems that affect the whole watershed. If these solutions worked as a networked infrastructure, tanks and infiltration devices could form a flood control distributed system and massive water reclaim.
Wastewater is the second main outlet of the ecosystem. Black and grey water have been damaging existing watercourses and coastal areas for decades, as a serious problem for public health in the city.
Hyperion treatment plant is the biggest in the US west, located in Santa Monica bay. During 20th century, it has been discharging wastewater with different treatment levels, because fast city growth made it impossible to process such volumes. The area close to the plant was totally polluted, decreasing healthiness in the whole bay area, that couldn´t preserve any aquatic life. The last extension in 1987 ended with a system overflow introducing secondary treatment for all effluent. Debris and organic waste are processed and transformed into biosolids that can be used as fertilizer for landscaping and agriculture and compost. Energy from bio-gas is used to produce steam for digesters.
The need for a different pipe network for recycled water means that re-using projects should be located close to the treatment plants, to reduce investment costs. customers of non-drinking water are golf courses, parks, public buildings with large irrigation areas, refineries and other industrial processes where water is used for cooling, besides the amount used for underground water recharge.
Garber Street Recycled Water Tank Project in Pacoima is necessary to further expand the LADWP “purple pipe” system in the San Fernando Valley. The site will provide the elevation needed for the tanks to maintain system pressure to serve current and future recycled water customers, the Valley’s Hansen Dam Golf Course among them.
Century and the Rio Hondo Water Reclamation Programs form a looped system of 65 miles of dedicated pipelines utilizing two pump stations to deliver up to 22,000 acre-feet of reclaimed water per year from the two largest Sanitation Districts’ Water Reclamation Plants (WRPs will supply tertiary-treated. with the reduction of imported water pumping comes energy savings of up to 66 million kilowatt hours per year, equivalent to 35,800 barrels of oil. This will result in the reduction of air pollutant emissions by up to 50 tons annually. East Valley Water Recycling Project which will bring treated wastewater to the spreading grounds below Hansen Dam for recharge into the groundwater
Bottled water brands and other drinks, like beer, create another loss of water. Their location in the territory indicates the presence of non-polluted aquifers and water sources.
8. FUTURE SPACES
The relationship between urban form and character with its green space network was essential from the beginning, its exceptionally mild weather, prone to dissolution of inside-outside limits and to programmatic confusion between both. Mediterranean climate and landscape values were included from very early as an attractive message by developers. ”outside space was the base of an economy capitalized in climate, sports and outdoor leisure” , however urbanization has not respected natural heritage areas. During the century several proposals have been made asking for urban planning that controlled private development, including social and ecological criteria with no success, and a lack of public spaces has been always growing.
LA RIVER revitalization master plan.
The role that the river has been taking in the general imagination has led to discovering the chance of turning it into a connector and backbone of a new hydrological and public space strategy. The plan is focused on recovering the river´s performative capacity and stormwater autoregulation in the watershed, without reducing current flood control, and enhances its potential as linear public space and an ecological corridor.
Current hydrologic features of concrete channels, with a much smaller section than original flooding plains, mean very high flow velocities for storms occurring every 25, 50 or 100years. Identifying areas where the river´s waters can expand, increasing capacity and reducing velocity, are combined with rubber dams and other devices to increase and control inside channel flow. The idea is very similar to the project built for Rio Besós in Barcelona.
Recovering riparian habitats and other landscape-based treatment systems contribute to improving water quality. Design guidelines for surrounding urban spaces, including permeable paving, bioswales and other domestic devices captures local water and treats them on site, reducing pressure on the channel.
Public access to water and river banks as places to stay or pedestrian routes contribute to transforming current concrete channels into public linear green spaces, which connect and articulate different neighborhoods. Also surrounding areas will be transformed to facilitate the rivers accessibility and legibility within the city.
The master plan proposes a full revision of watershed hydrologic performance, distributing stormwater control, harvesting, treating and re-using at different scales, showing the possible integration between public buildings and spaces and urban water management. Despite existing expectations of a river restored to its original state, based on arcadic archetypes of urban nature, the master plan shows infrastructural ecosystems as something worthy, and its possible transition to a more efficient situation, performative and more diverse.
Iconic palm trees have given place to a more performative concept of urban nature, related to ability to modify environmental conditions, as organic machines that provide shadow and oxygen. Other plant species more efficient and less water dependent will be considered. In this context of entanglement of plants and housing, the operating capacity of green systems, understood as organic infrastructure, is especially interesting.
Building large scale technological systems for water supply, irrigation and energy is an essential element in the rationalization of nature. Integrating the hydrological cycle in urban dynamics has produced not only a material change of urban environment, connecting natural landscapes of California with a multiplicity of private spaces within the city, but also a symbolic landscape of political and cultural power.
The combination of utilitarian modern aesthetics with a functional compromise with regional resources rationalization becomes the symbol of a new sort of public space. these “democratic pyramids”, sharing Lewis Mumford´s words, represent a unique conjunction of technology, nature and public politics, but its longevity shows the fragility of the particular political and cultural circumstances that gave place to its construction. The initial relationship between water scarcity and public works has been displaced by increasing concerns about water quality and the difficult maintenance of the tangled mess of pipes, connections and relationships that constitute the invisible city that supports urban life.
This change of paradigm leaves doors opened to other ideas about urban nature, “it is only by radically reworking the relationship between nature and culture that we can produce more progressive forms of urban society. The reworking of modern nature is a collective project that applies the human imagination to the transform of urban space and affirms the interdependencies that sustain a flourishing civic realm” .
Carolina González Vives
Source Los Angeles Department of Water and Power. Urban water management plan, 2010
It is interesting to compare these numbers with the distance from Valmayor reservoir in Madrid, to the Canal de Isabel II tank inside the city, which is shorter than 40km
source Institute of the Environment, UCLA
Marc Reisner “Cadillac desert. the American west and its disappearing water”,(1986) pg. 6,8
superposition of historic cartography and current city is a very useful tool in order to reorganize urban runoff, see http://www.ballonahe.org
Mike Davis, idem
Warren Techentin, “landscape: tree huggers“ article en “The infrastructural city. Networked ecologies in Los Angeles” edited by Kazys Varnelis (2008)
Matthew Gandy “Concrete and clay: reworking nature in new York city” (2002)