Manuel Aliaga Martinez
LA PAZ
2014-2015
meshing water flows
meshing water flows A landscape urbanism investigation of
LA PAZ
2015 K.U. Leuven Master of Urbanism and Strategic Planning, European Postgraduate Masters in Urbanism Author: Manuel Aliaga Martinez Promotor: Bruno De Meulder
LANDSCAPE URBANISM THESIS PROMOTOR Bruno De Meulder TUTORS Claudia Rojas Bernal Matteo Motti Julie Marin
MORE INFO ? MAHS / MAUSP / EMU Master Programs Department ASRO, K.U.Leuven Kasteelpark Arenberg 1, B-3001 Heverlee, Belgium Tel: + 32(0)16 321 391 Email: paulien.martens@kuleuven.be © Copyright by K.U.Leuven Without written permission of the promotors and the authors it is forbidden to reproduce or adapt in any form or by any means any part of this publication. Requests for obtaining the right to reproduce or utilize parts of this publication should be addressed to K.U.Leuven, Faculty of Engineering – Kasteelpark Arenberg 1, B-3001 Heverlee (België). Telefoon +32-16-32 13 50 & Fax. +32-16-32 19 88. A written permission of the promotor is also required to use the methods, products, schematics and programs described in this work for industrial or commercial use, and for submitting this publication in scientific contests. All images in this booklet are, unless credits are given, made or drawn by the author (Leuven 2015).
The confluence of three main rivers: Hua単ajahuira, Choqueyapu and Irpavi in the city of La Paz
2
intro
THE INVISIBLE ABSCENCE OF [Development] URBANISM The city of La Paz and its lack of development urbanism, understood under the transformation of the built and natural environment by connecting the context specificity of design practice with non-specific issues such as social-exclusion, poverty, unsustainable construction and urban growth [1], is barely recognized and openly accepted as such, hence it is invisible. The reason for this belief is that there is still a very strong presence and aspiration for the dogmatic modern project attached to urbanism. The last traceable attempt of modernist urbanism in the city of La Paz was when the architect Emilio Villanueva draw the plan for the then new Neighbourhood of Miraflores in 1941, thus influencing the regulator zoning plan for the city in 1956, regularly updated until now. Since that period a feeling of trying to catch up with progress, along with the neverquestioned outlines of the modern project, are still today the paradigms to be followed in the mind of many of La Paz´s citizens in their roles of actors and decision makers. The rivers and creeks of La Paz provide a two way example of the developing condition of the settlement: on one hand a strong presence of vernacular practices of dealing with water and on the other hand the aspiration to follow the modernist city where such vernacular practices do not have a place. As a direct result of the disadvantaged conditions of the developing water system; rivers and creeks are polluted because they are used as sewages and later used for irrigation. Rivers and creeks are also transformed into streets and avenues on a frequent basis, as part of the normal and unique path to achieve modernity. Streets and avenues have become one of the most important and popular cards of urbanism in the local practice, not because everyone has a vehicle, as the discussed examples of La Paz´s developing conditions, but because in the street is projected an aspiration of public space, services and maybe more importantly recognition. The research project has been developed in this frame of developing urbanism: recognizing the contextual limitations as opportunities for urban intervention without giving up the ambition of urban design inherited from the modern movement. In other words this work tries to bridge and design both in the specificity of the context of La Paz, while dealing with the non-specific issues such as urban growth, unsustainable water management and climate change.
[1]. D´Auria Viviana, De Meulder Bruno, Shannon Kelly, “The Nebulous Notion of Human Settlements”, Human Settlements Formulations and (re) calibrations,, Sun, Amsterdam, 2010.
3
Chapter 0 Urbanization without landscape/ landscape without urbanism
analysis Chapter 1 Enclave of 3 Eco[logics] 3 Ecosystems Framing the Settlement in the valley Compact settlement/ dense tissues
Chapter 2 La Paz catchment The city and the rivers The rivers and the city Recovering the invisible rivers
hypothesis Chapter 3 Water flows Upstream/ Downstream flow Micro stories/ Issues Water flow system Meshing water flows
project Chapter 4 Exploring scenarios for the water mesh
intro Chapter 0
LA PAZ Urbanization in Latin American cities is often characterized by the unbalance of condensed capitals that have at disposal a vast and available territory that is rarely planned. The case of the city of La Paz shows that a great part of the subsistence of this great urban centre rely mainly on the consumption of natural resources of the surrounding landscape. The unrestricted consumption of land, water and other resources keeps extending the city and its borders indefinitely. As a result of this model of urbanization, water management has transformed natural features (such as streams and rivers) into hybrid figures that flow across the city (its main river now is both a sewage and a stream) that with climate change have proved to result unmanageable. The city of La Paz, located at an altitude of 3500 above the sea level, is the main city of Bolivia and becomes an interesting case study. The city has grown slowly for more than 436 years, and experienced a spontaneous growth in the past 30 years, due to countryside migration that led nowadays to a population of almost two million inhabitants along with its twin city: El Alto. The city is settled on a highly dense hydrological system as part of a complex sequence of valleys and hills in which the riverbanks were mostly used to contain the growing city, therefore the system of rivers and creeks have served in the beginning as clean water supply and later as drainage for the consumed
water. For centuries the frozen water on the highest peaks of the Andean east mountain range have feed more than 300 creeks of fresh water through the valleys of La Paz. The relevance of the river valleys has given a serpentine structure of urbanization that nowadays continues guiding the city´s growth. Another image of La Paz is valleys and rivers frozen in architecture and streets. These small and large streams were gradually reduced on size and used as sewers and culverts that flow openly across the new urbanized areas and under vaults in the oldest areas of the city. Grey water and dark water flow into these streams creating a hybrid between a natural stream and an outdoor sewage that crosses all over the city, where it is difficult to identify weather it is an open sewage or a contaminated river. The main rivers and tributaries receive an important volume of water coming from the ice melting stratum, from the human consumption and additionally from the increasing heavier rain season that lasts four months, all these amount of water ends up in the reduced in size and canalized rivers. The capacity of the current system is already collapsing and other issues such as water supply, climate change, and contamination are still matters pending to be reconsidered.
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AS A RESULT OF THIS MODEL OF URBANIZATION NATURAL FEATURES SUCH AS STREAMS AND RIVERS HAVE BECOME HIBRID FIGURE AS THEY ALSO ARE THE CITY´S SEWAGE THE PRESSING ISSUES ONLY GENERATE MORE VULNERABILITY TO AN ALREADY EXISTING INSTABLE URBAN ENVIRONMENT
The renovated Bolivian constitution [1] subscribes accessibility to clean water as a right, this status was achieved through an active and constant struggle of social movements that started in the year 2000 [2]. In the city of La Paz water supply reaches to 92% of the population [3], 70% of the consumed water goes straight into La Paz´s main river Choqueyapu: while the rest 22% of consumed water uses its tributaries of the same river as sewage. Due to the lack of treatment plants, adequate sewage infrastructure and mainly due to a linear centralized water system, the polluted hydrology is affecting the metabolism of the city [4] that not until so long ago was still sustainable. Nowadays downstream crops, sold in markets of the city, are irrigated with contaminated water [5] , showing alarming levels of contaminated food. In addition climate change has put in risk the convenient coverage of water supply obtained so far, due to its static dependence on the reducing frozen layer on top of the
peaks. Warnings about cutting the service due to the incapacity of the system have already been made, and the new master plan for water management needs another 36 years to implement water supply for the whole population. However a much more palpable symptom of lacking an integrated vision is that each year La Paz and Bolivia suffer an increasing manifestation of phenomena disasters whose origins come from hydro meteorological conditions [6]. The pressing issues described above only generate more vulnerability to an already existing instable urban environment threated constantly by landslides, flooding and water excavation. “...water had become an extremely pressing issue: water as a resource and necessity, water as a potential threat, with growing water consumption that has become difficult to fulfil and water pollution reaching such levels that the most basic ecological balances were disturbed.� (7) 5
Urbanization without landscape
Since the foundation of the city of La Paz in 1548 by commandment of the Spanish Crown, the superimposition of the grid would constitute the first step of a rooted urbanism practice that believes that urban planning consists in reproducing the latest urban figure. In this sense is that the contextual qualities of La Paz were never taken into account, furthermore little attention was paid to the specificity of the landscape and the social scape.
After 1941, the city has progressively lost its range of action upon urban planning, during the coming decades the city suffered spontaneous growth due to rural migration leaving no space for urban planning. The river became the city drainage and the river valleys the city dumps.
Until today this logic of reproducing automatically models, images and figures on the city without looking at the contextual conditions of La Paz leads general public to believe that many of the water related problems are present because of the inefficient size and volume of the infrastructures containing the trapped rivers, and that the only two possible solutions for the exciding volume of water in the city is thicker concrete, stronger bridges, heavier foundations, wider containers for garbage. The biggest mistake of La Paz is believing it is a city like elsewhere.
6
THE BIGGEST MISTAKE OF LA PAZ IS BELIEVING IT IS A CITY LIKE ELSEWHERE
THE POLLUTED HYDROLOGY IS AFFECTING THE METABOLISM OF THE CITY [5] THAT NOT UNTIL SO LONG AGO WAS STILL SUSTAINABLE
Landscape without urbanism The extreme contamination of La Paz´s main river, the water shortage , plus the big flooding in 2002 and the landslide in 2011 seem to uncover the issues related to a questionable water system in the city: while the water supply is mainly fed by the melting of mountain glacier, with climate change the provisions of freshwater threaten to diminish accessibility to freshwater in the coming years, yet during the rainy season the city becomes an instable environment in which disasters are reported yearly due to a large volume of water discharged into sewage and streams producing ground excavation. The contradiction relies in having a current model of urbanization that puts pressure on natural features by transforming them into artificial (the main river becomes the major sewage collector) while artificial originated events (landslides, flooding's) become natural disasters forces to be domesticated.
This problematique leads to formulate the research question on what if a Meshed Water System that performs as a Grid provides the opportunity to deal with climate change, water pollution, water scarcity, while generating a new stream based urbanization? [1] 2010: a new constitution was approved within an important participation process. [2] 2000: This year is considered as the starting point of the social changes experienced in the recent history of Bolivia, of which the new constitution is also part of this transformation. The event that triggers the sense of inconformity with the radical neoliberalism model is when the then national government approved an international company “Suez” to privatize the existing natural sweet water reservoirs including possible rainfalls. [3] 2010: Source EPSAS Agency of water supply. [4] Wolman Abel, The metabolism of cities, 1965. [5] Several lab studies confirm that the polluted agents found in the river return in form of diaseases in the vegetables cultivated downstream. [6] 2010-2011: a thousand and nine adverse events have been registered only in this year according to UN Program for development. [7] De Meulder Bruno, Shannon Kelly, Water Urbanisms East. UFO 3: Explorations of Urbanism. Park Books: Zurich, 2013.
Kenning Willy, 1995 . The friction between two strong forces: urban development and landscape
7
WHAT IF A MESHED WATER SYSTEM THAT PERFORMS AS A GRID PROVIDES THE OPPORTUNITY TO DEAL WITH CLIMATE CHANGE, WATER POLLUTION, WATER SCARCITY, WHILE GENERATING A NEW STREAM BASED URBANIZATION?
The northern valley of La Paz 1915 before rapid growth at the end of the century.
The city´s struggle; a clash between the built and the natural environment
10
analysis Chapter 1
Enclave of 3 Eco[logics]
WATER Amazonian catchment
GROUND Andean Mountain Range
RELIEF Andean High Plateau
11
WATER + GROUND + RELIEF
An important section of the south American continental Land is defined by three impressive ecological systems: The Amazonian catchment, The Andean Mountain Range and the Andean High Plateau or “altiplano” .
12
Amazonas
Madeira
WATER Beni Lake Titicaca
Lake Poopo
GROUND
5 4 3 2 1km
RELIEF Altiplano
TEXTURE
13
WATER + GROUND + RELIEF + TEXTURE
The source of water of the Amazonas River comes from the melting layer of the east glaciers of the Andean Mountain Range. La Paz´s system of rivers becomes part of this water course. In a very short distance the topography dissension goes from the peaks at 5000 meters above the sea to less than 1000 in the tropical plain. The city of La Paz and the water course in this area is characterized by the speed of discharge. In this section the Andes splits into
two ranges (east-west), creating the high flat plateau at a great altitude. The water system on the high plateau between the mountains is closed, the two main lakes Titicaca and Poopo and river form part of this isolated water system. The sequence of the textures along this section, show a drastic and contrasting change in climate and vegetation defined by the altitude. From the dry and cold high plateau, through the humid and cloudy mountains to the 14
warm and rainy tropical plain, the drastic shift between ecologies is characteristic of the tropical glacier water course..
analysis
3 Ecosystems
El Alto
La Paz
HIGH PLATEAU
MOUNTAIN RANGE
15
TROPICAL VALLEY
ALTIPLANO
ANDES
The high plain is a unique ecosystem at an elevation altitude between 4000 and 45000 meters were many of the ancient civilizations of the region first established. Many of these early settlements occupied territories around the Lake Titicaca catchment the highest lake in the world. This lake is part of the closed water hydrology that runs inside the plateau. The city of El Alto the second largest city in Bolivia is settled on this ground right next to the valley of La Paz.
The Mountain Range runs northsouth of the continent, this orientation structures a diverse sequence of landscape transects. At its widest transect it splits into two branches holding the high plain in-between, the city of La Paz is settled next to the plateau beneath the eastern arm. The melting layer of the peaks along the mountain range feed several lagoons, La Paz´s clean water supply comes from these artificially enlarged lagoons that later become the source of the Amazonas.
YUNGAS
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The “yungas� or the tropical mountain system is a very humid and fertile system, the sudden drop of altitude from higher peaks to the tropical plain allows to have a radical change in the climate: gaining a degree in temperature for every km down stream. Taking advantage of this ecological levels most of the productive lands are settled along water courses, having the city of La Paz settled on an important irrigation water course. The city becomes a distribution enclave, as well as a consumer of the produce.
analysis
Framing the settlement in the valley
TOPOGRAPHY The valley of La Paz is characterized by a troubled topography and steep slopes, product of an upstream hydrology erosion in two epochs: upper glacier erosion– lower valley erosion. The altitude in the highest point of the valley is 4000 m while in the lower reaches to 2800 m.
GROUND The confluence of three parallel river valleys running from northeast towards south define the central plain, where the city has settled and grew. This systems of valleys and hills opens up as altitude and slope decrease towards south hence the urban growth has been guided in this direction.
SETTLEMENT Urbanization has followed the river plain areas in order to colonize, the slopes and the hills. Growth of the city has been empirically oriented by the conditions of the terrain yet never achieved an harmonic integration.
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TOPOGRAPHY + GROUND + SETTLEMENT
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LEVELS + TOPOGRAPHY The valleys are product of water erosion, having as a counterfigure the hills, hence there is a remarkable difference in the levels. The sequence of levels conveys into a central white area in the south corresponding to an altitude of 3300m in contraposition to the dark hills in the north at 4500 m in a distance of 10 km.
SLOPE The short black arrows show a steeper slope, while the longer ones represent areas where the inclination is less steep. The white central area is where the city first settled expanding gradually to the valley slopes, when these were increasingly more difficult to occupy urban growth kept expanding its sinuous linear figure.
WATER + URBAN IMPRINT
Urban imprint is the result of settlement along the main rivers plains running diagonally and the colonization of slopes from the central valley to the river valleys on the periphery according to the gradient of inclination.
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LEVELS/TOPOGRAPHY + SLOPE + WATER/URBAN IMPRINT
4500 m
3900 m
0
3700 m
3300 m
3500 m
1 km 20
4300 m 4100 m
3900 m
analysis
Compact settlement/ dense urban tissues
3500
3400
0
3300
500 m
ON TOP OF HILLS
ON VALLEY SLOPES
21
ON RIVER PLAINS
Urbanization on top of hills Urbanization on valley slopes Urbanizations on river plains
0
TOP OF HILLS The urban tissue on the top of hills and small plateaus is normally planned, reproducing a small scale suburban typology having a front and a back courtyard. The density of this tissue is not medium-high: the buildings don´t reach more than 5 stores because the plots have a medium size , they don´t allow high rise buildings and they are not compressed by terrain conditions. Informal settlement grows around areas with more distinctive natural borders such as cliffs and cracks.
1 km
VALLEY SLOPES This kind of tissue is normally planned in the areas near roads, but also has its unplanned counter part in the steeper slopes of river valleys. Thus settlements and buildings are both formal and informal. Planned buildings usually have wider plots, while further up urbanizations have narrow plots because of the increasing slope. The density of this tissue has a tendency to be high due to the construction of taller buildings (5-6 stores) in the lower areas and also due to the intensive use of the land in steep areas. 22
RIVER PLAINS The urbanization in the river (flood) plains can be described as the “better placed” because is the most stable and important urban destinations as well as important buildings are normally settled on these plains. The city grew up following river plains; it counts with large plots, it is in between important roads, hence it is accessible, and lastly it allows for high rise development to take place. The taller constructions are precisely on central river plains. The density has a tendency to be high due to the increasing investment in towers.
Lanza, Leonardo. 1877
The rivers of La Paz are usually backside spaces until they are covered and become avenues.
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analysis Chapter 2
La Paz catchment
CATCHMENT AREA The catchment area gathers three main courses upstream at the source around the mountains of Chacaltaya in the north. The valley of La Paz is placed in the middle course of the catchment, where similar mountain source tributaries meet.. Agricultural lands are settled in the lower catchment area having smaller rivers from underground and pluvial source in the south.
Kaluyo
NATURAL WATER FLOW
Choqueyapu
The main course of water receives the name of Jhunu Tincu Jauira in the upstream melting source, after joining with other two streams it is called Kaluyo river. When entering the city it becomes Choqueyapu, becoming Río La Paz further down after the confluence of the eastern tributaries.
Río La Paz
RELIEF The relief is defined firstly by the three major ecosystem on the territory, in the catchment area four parallel valleys run diagonally from northeast to southwest. The valleys are defined by four tributaries of the main course: Orkojahuira, Irpavi, Achumani and Huañajahuira. After crossing a perpendicular hill system, from which the valley becomes a more recognozible figure, carrying water towards south only to make a turn to the north to reach the Amazonas.
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CATCHMENT AREA + WATER + RELIEF
0
5 km
26
analysis
Sinuous growth + rapid urbanization
La Paz is an old city, up till now trails of pre Columbian cultures can be found dispersed along the valleys. Originally funded in the Altiplano in 1548 , it was temporally placed in the former valley for the assigned Royal comadment. In the colonial period the evolution of the settlements and its population was not significant, although its position between Cuzco and Potosí, as originally planned, consolidated La Paz in the valley definitely. From 1790 with 53.340 inhabitants [Mesa, Gisbert La Paz en el siglo XVII] until 1912 with 78.856 urban growth has been much less acceler-
ated. The great expansion happened during the end of the twentieth century. “The present century is fundamental in the history of the city. The balance kept between the physical implantation and its natural space suffers a significant transformation” (1). In the first period of this century many infrastructures of great relevance were implemented, however the effect of these projects was rapidly overcome by population in a matter of years, meanwhile the expansion of the city followed the less steep areas meaning river 27
plains, this generated a linear figure that started to twist and turn. “The urban expansion project of Miraflores is the most serious attempt to decentralize some of the urban functions […] in addition to offer areas for high density” (2). In the decade of the 70´s the economic system led to a strong dependency of the urban centres.
Flows of migrants coming from small towns across the plateau arrive to the city and consequently an important expansion of the urban imprint has taken place in every direction, first the river valleys and after the slopes creating a sinuous system of lines that follow the winding river valleys over the territory. The population growth overcame largely the investments, the environment changed extremely, the rural area suffered deterioration as well as the land, environment and water.
Occupation of areas that represented risk for construction, pollution, erosion and more important low quality in the new living conditions of the city dwellers were the first signs of the loss of planning and control over the territory.
Between 1990 and 2000, the deterioration of the city´s natural and built environment was already visible affecting the hydrological system significantly, additionally during this period it was registered several disasters attributed to nature, including major landslides due 28
to the densification of the valley´s steep slopes. [1] Free translation Villagómez Carlos, La Paz ha muerto, La Paz 2004. [2] Free translation Cuadros Alvaro, La Paz, La Paz 2003. .
analysis
The city and the rivers
Gerardus Mercator 1569
One of the first cartographers to draw the region was Mercator; in his series of maps of the world in 1569. The city of La Paz is a small village on a river drawn under the name of “Cuchiao”, the native name of the river in the valley. In 1613 according to Guaman de Poma chronicles the city of La Paz was still called “Civdad de Chvqviiapo” which is refering in an ancient Spanish, to city on the river currently called “Choqueyapu”.
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Guaman Poma de Ayala
The first name of the city of La Paz was precisely after its main river “Choqueyapu”. By 1652 the city is called La Paz, unlike the Mercator map in the map in which the settlement is drawn as part of the puna, 83 years later in the map of Nicholas Sanson d´Abbeville the river is correctly drawn as part of the Amazonian catchment.
Amazonas
La Paz 1652
Adapted from Sanson d´ Abbervile 1652
30
During the colonial period in Bolivia (century XVI-XVIII) the division between the Spanish city and the indigenous city was of course not only spatial, there were marked social classes and the indigenous population was not able to enter the Spanish city. This restriction led the development of a marginalized city established in the periphery of the Spanish grid, where the Choqueyapu river was the border.
First settlements in 1548
For the majority of the population the river, the main indigenous church (San Francisco) and the regional roads defined important spatial structures where most of their everyday activities took place (Cuadros 2003).
The Spanish city century XVI, Mesa Gisbert 1960
The painting by M. Florentino Olivares 1880 is a representation of the siege that took place in 1796, when an indigenous rebellion isolated the city of La Paz leaving the colonial city, its Spanish inhabitants and its defensive wall in precarious survival conditions. This siege lasted nine months, but the colonial border stayed longer.
M. Florentino Olivares 1880 [upside down for orientation] 31
TOPOGRAPHY+ HISTORICAL MAP 1796
0
1 km
Adapted from the first official map of the city 1796
32
La Paz of 1846, maps of the National Territory, 1859
The urban development of La Paz revealed in this period the need to expand throughout routes and connections from the compact settlement defined by the Spanish grid, therefore in this period the construction of bridges across the different sections of the rivers is a remarkable aspect of the period (up to 1880 a total of 21 bridges were built). Similarly, the consolidated neighbourhoods communicating arteries were improved according to structural reforms of the time, with the projection of the city’s urban expansion.
By the late nineteenth century, this expansion had come to agricultural areas that were urbanized transforming them into residential neighborhoods. It is estimated that the urban area consisted of 184 hectares, and housed around 42,842 inhabitants (Villagómez, 2004).
Engraving of the main Plaza of La Paz, 1877
Engraving of the main Plaza of La Paz, 1880
33
TOPOGRAPHY+ HISTORICAL MAP 1877 + MAIN RIVERS
0
1 km
Adapted from Leonardo Lanza 1877
34
After the Federal War (1899), La Paz is set as the final political centre of the country. The importance of the city within the national scale had an important influence on its urban development, reflected in a map that begins to show the peripheral areas as an inevitable new destination for the most recent settlements.
Train crossing the river, early XX
Water excavation caused by the river, tram lines hanging. 1933
Choqueyapu river before Avenida Montes, early XX
35
The rapid urbanization process, in the earlier century, was materialized in a significant amount of works. These transformations became a significant improvement of the urban quality of life, such as opening of new avenues, improvement of the canals and water recollection reserve system, and the installation of electric lighting in 1905 along with other urban constructions. This process was accompanied by a significant population growth in the city. (Villag贸mez 2004).
TOPOGRAPHY+ HISTORICAL MAP 1912 + HIDROLOGY
0
1 km
Adapted from the municipality official map 1877
36
By 1950 the sinuos figure of urban expansion following river valleys had been consolidated; the expansion to the then new river valley in Miraflores defined by the Orkojahuira river had already been traced and followed, and this gave rise to expansion towards the southern Valleys. Rivers started being canalized as a usual practice for urban expansion, it is the starting point of and incipient but increasing contamination of water bodies and the start of an urban practice of expanding infrastructures on creeks and rivers in order to become urbanized areas.
From the aerial picture it is possible to recognize how much the river plains were reduced, already by 1950 the Choqueyapu river is under a vault in the historical centre.
Vaulting the river opening Avenida Troncal 1935
Choqueyapu canalized, before Avenida del Poeta , 1960 37
AERIAL PHOTO 1950 + HIDROLOGY
Adapted from aerial photo 1950
38
micro story
Canals & Vaults 2010
2010
1900
2010
2011
2010
39
Felipe Aliaga, 2010
Archive Miguel Irigoyen, 1950
“THIS IS THE FIRST INDICATOR OF A PRACTICE OF URBAN ARTICULATION BY BRIDGES, THAT IS CHARACTERISTIC IN THE URBAN DEVELOPMENT OF LA PAZ”[1]
canalized 1960 In the city of La Paz, Choqueyapu; the main river and its tributaries, have performed in different ways along the history. In the colonial period the river was more than a natural barrier as it served to separate the Spanish city from the indigenous city, its name means Lord of Gold, which in the native language talks about another of the earlier functions of the stream: gold washing. Rather soon the first infrastructures were built on the Choqueyapu, the bridges are an earlier stage of what later upgrades into canals to become vaults and maybe streets or avenues. After the colonization of the valley of La Paz and after using the river to segregate people, the next stage was (and still is a usual practice) canalizing the river in order to gain more space for urban expansion. The practice of vaulting rivers comes from the need to trace avenues and the need to cover the pollution of the rivers that gradually became sewage. A vault is an extended bridge and/or a sewage.
double vault 2010
street 2012
The river valleys have served for different spaces, facilities and functions of the city. The Choqueyapu runs next to the main access highway, later when entering into the city it is vaulted and becomes the main avenue of La Paz. Its remaining bank in the centre has become the Central Urban Park, although the river lies under two massive vaults through the park. After 3.5 kilometres under a vault it is open again between canals of 6 meters where the second largest river of the city the Orkojahuira joins its course. The river runs across newer areas of the city for 4 and a half km. In the lower course after joining waters with two other main rivers it runs openly without canal.
The double vault 2011, in the Central Urban Park is the most recent and visible practice of large infrastructures upon rivers, the construction is not part of the designed master plan of the park, it was built to stabilize the talud of both slopes as well as to cover the polluted river from being used as dumping area. Now it is a pedestrian street. The double vault is part of a restoration project of the vaults in the city centre. “It has been worked in the structural reparation of canals and vaults” of the Choqueyapu river and its affluent. (3).
“In the city of La Paz, the courses of the rivers can be classified according to the existence of hydraulic infrastructures: Rivers without infrastructures 10%, open canals 30%, former canals and vaults 60%.”(2)
40
[1] Free translation Villagómez Carlos, La Paz ha muerto, La Paz 2004. [2] Free translation Estrada Liz , Propuesta técnica para la implementación de sistemas ecológicos de desinfección de las aguas del río Choqueyapu, Thesis presented to the faculty of industry engineering Bolivian Catholic University, La Paz 2004. [3] Free translation , Publication of the Municipal Government of La Paz, La Paz 2010.
analysis
The rivers and the city
Case study section
N
AERIAL PHOTO 1950
CASE STUDY SECTION 2015
Contunuos vaults
2015
41
NATURAL COURSE
1796
1846
1877
1912
Trunk Avenue project
1950
42
analysis
Uncovering the internal hydrology
INTERNAL HYDROLOGY + TOPOGRAPHY
URBAN IMPRINT + TOPOGRAPHY
URBAN IMPRINT + URBAN FABRIC
43
INTERNAL HYDROLOGY + URBANIZATION + TOPOGRAPHY
44
INTERNAL HYDROLOGY
VISIBLE HYDROLOGY
45
It is rather difficult to map the hydrology in the city of La Paz, since main rivers and creeks have been vault and put into thin channels, they are no longer visible. Contemporary data provides an insight of what the hydrological system could look like, hence it is possible to make an interpretation of the internal hydrology that lies under the city, therefore it results important to make a distinction between the internal (originated by nature) hydrology and the one that is visible. The changes in the natural hydrology of the valley, that are not natural changes, has an important influence in the performance of the greater system. The rapid variation in the altitude of the terrain accelerates water in upper courses such as the one in the valley of La Paz causing rapid erosion. By
reducing the size of the rivers, water flows even faster gaining speed and becoming an massive force capable of excavating concrete and carrying big stones. The progressive work of infrastructures upon rivers has reduced significantly the presence of space for water in the valley, once a vast mountain creek wetland, the city of La Paz is trying hard to transform its arid atmosphere. The visible hydrology shows incipient rivers and discontinous flows. The main rivers disappear or become thin lines. The internal hydrology on the other hand shows indeed a very dense hydrological system spread out through the valley. By comparing both the visible hydrological system and the internal hydrology the result is a very
46
contrasting final image between each other. “With urban growth and the canalization, [rivers] have not only hidden , but in some cases diverted their natural courses.“ (1)
[1] Free translation, Medinaceli Ximena , “¿La Paz ciudad de cerros o de ríos?”, Ciencia y cultura no 7, Universidad Católica Boliviana, La Paz 2000.
intermediate conclusion
Recovering the invisible rivers
LEVELS + HYDROLOGY
GROUND + HYDROLOGY
LEVELS + GROUND
LEVELS + URBANIZATION
HYDROLOGY + URBANIZATION
TOPOGRAPHY + URBANIZATION
INFORMAL SETTLEMENTS
HISTORICAL TISSUE
VOIDS
47
CONCLUSION MAP OF ANALYSIS
10
48
The municipality official map, of 1912
49
Water pollution and water accessibility facing climate change are the main challenges ahead.
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hypothesis
Water flows
DRINKING WATER FLOW The drinking water supply comes from the melting ice cape of the surrounding Range, the four lakes artificially enlarged become the drinking water reservours: Milluni, Incachaca, Hampaturi , Tuni condoriri and Ajuan khota. Three main pipe lines supply the drinking system network, two purification plants are located away from the city and the two plants located within the city are the sources of distribution to the rest of the city.
CONSUMED WATER FLOW Consumed water follows the natural courses of the rivers meaning that the rivers work as the consumed water collectors, due to the lack of independent pluvial-rivers system and sewage system. The quality of water is defined by the Index of Water Quality that throughout chemical and biological tests it can be defined [1] where blue is very good, green is good, yellow is medium, orange is bad and red is very bad. The water flowing in rivers in the city is very bad, while the flow leaving the city does not improve its quality significantly. (1) Free translation ICA Indice de calidad de Agua, Report on the contamination of the catchment of the River La Paz. Bolivian national comptrollers office, 2013.
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WATER FLOWS + QUALITY OF WATER drinking water very good quality
good quality
medium quality
bad quality
Tuni condoriri
Milluni Ajuan khota
kaluyo Incachaca
Hampaturi Orkojahuira Choqueyapu
Irpavi Achumani
Huañajahuira
Río La Paz
0
5 km
52
very bad quality
WATER FLOWS+ GROUND + PLACE
FLOW SOURCE Andes Eastern Range
FLOW ARRIVAL Agricultural fields valleys
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WATER FLOWS+ GROUND + RELIEF
FLOW SOURCE Andes Eastern Range
Purification plants
FLOW ARRIVAL Agricultural fields valleys
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hypothesis
Upstream / downstream flow
Water courses in the valley of La Paz perform accordingly to the altitude or section; at the higher section of the course it is used for water supply, in the middle section it is used as an effective flush, and in the lower section it is used to irrigate crop fields. This changing performance has not been properly considered since any intervention made in a section of the course of the river will definitely have an important impact in the following section of the course. A distinction can be made between water flows according to its performance. There is a drinking water flow which has been properly engineered in order to take advantage of the natural
system as the melting flows of the peaks provide a valuable source of clean water, this input is stored in artificially enlarged reservoirs which trough piping reaches to filtering plants that distribute drinking water to the city. Already at this section of the course there is a hybrid natural and artificial flow system. The second flow refers to the course of water that follows after is been consumed in the city, this flow of gray and black water, but also water from industry is flushed trough out the natural systems of creeks and rivers off the city, this action created a contradiction: Are the rivers polluted or are they an open sewage?
DRINKING WATER FLOW
CONSUMED WATER FLOW
NATURAL WATER FLOW 55
Perhaps the most visible example of the impact of this hybrid natural-artificial flow system is that downstream agriculture fields are irrigated by the city´s water flow. The natural-artificial system built so far from source until the city becomes natural again. Rio La Paz recovers its natural state (it is open without any hydraulic infrastructure anymore), however the quality of its
Kenning Willy, 1995 Aerial view of Rio La Paz a nd agricultura fields
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water remains still as bad (orange color). An artificial flow system has been introduced to the natural flow of the course of waters to provide water supply and water drainage. Consumed water doesn´t have enough distance to depolluted on its own before is used to irrigate agriculture crops downstream. Little attention has been paid to the water flow system as a whole.
polluted water polluted food
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micro story Issues
WATER POLLUTION decreases the quality of life of people that uses water for consumption or for production , not having direct control of this variable , that is controlled by economic agents where populations does not receive any compensation in exchange.“ (2)
The city of La Paz with its 793.000 inhabitants uses most part of the catchment as residual water collectors. In the city there is no separated system between pluvial, domestic and industrial consumed waters, where most part of the contamination of the river responds to industrial and domestic water flows, occasionally tributaries are also used as dumping sites. According to a study of the Japanese agency Jica 1993 the water of four affluent of La Paz´s main river show that the quality of the water is similar to residual water treatment plants than to other comparable rivers.
In 2013 an important study led by comptrollers office concluded to the same recommendation stated by Jica in 1993; the quality of water of the main rivers in La Paz is not suitable for irrigation or consumption. This last study unlike others urges to public institutions to take actions and urges to the elaboration of projects and plans. In response currently is under revision a Master plan for water management for the next 36 years for the metropolitan area of La Paz, the depollution proposed project returns to the highly engineered centralized view of the Jica project which focuses on building a major treatment plant that aims to de-pollute the water flows onwards. The problem with this kind of approach is not only the lack of space for such big infrastructure between the city´s border and the agricultural fields down stream, taking into account that the city is expanding, but that it assumes that the river and its catchment is indeed a sewerage , that environmental integral sustainability is not a goal and that water can be controlled in centralized systems. Water pollution in the city of La Paz is may be the most urgent challenge after vulnerability to overcome in the immediate future. “ The study concludes that an ecosystem constituted of polluted water bodies has been damaged and real risk and consequences for public health derives from this issue.” (3)
Rivers have a self cleaning quality and are able to bear some pollution, this is not the case of the Choqueyapu and La Paz rivers anymore as the polluted waters irrigate agriculture fields downstream that are sold later in the city markets. “ The Choqueyapu river of the city of La Paz is a clear example of water pollution, it is estimated that 50.000 litters of urine and 0.2 ton of excrement are poured into the river daily. Everyday it is poured big quantities of garbage , construction waste and even high toxic liquids from dumps. […] These waters that flow almost through the whole city carrying great stink irrigate approximately 600 hectares down stream, that is mostly used for agriculture and the production of fruit trees having these products being commercialized in the different markets of the city” (1). Studies have concluded that at least in three communities downstream in which the main activity is agriculture, present unacceptable crop production for human consumption. With this negative cycle closed, pollution comes back to people in the city, diminishing significantly the quality of life and public health.
[1] Free translation Revollo Daniel, “Contaminación del río Choqueyaou”ABC Economía y Finanzas No 38, La Paz 2003. [2] Free translation Ibidem
Besides the contamination of the river should be analysed as a negative external issue because the contamination
[3] Free translation Report on the contamination of the catchment of the River La Paz. Bolivian national comptrollers office,
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micro story Issues
WATER ACCESSIBILITY / CLIMATE CHANGE CHACALTAYA SOURCE MELTING GLACIER
INCREASING RIVER TORRENTS
59
“The children that today arrive to the world won´t believe that we used to play with water” (1)
The major contradiction of looking at La Paz´s main source of clean water being reduced drastically in a couple of years and having an increasing rainy season that lasts four months in which the amount of water overpasses the built infrastructures, speaks about the fragmented way of managing water that has been put into practice until climate change has made it clearly evident. The melting of the Chacaltaya Glacier illustrates how oblivious and fragile is the current urbanization model in the city of La Paz. Climate Change and the challenge of getting fresh water to the city is still a question to be answered. On the other hand during the rainy season from November to February citizens live in Alert state due to the heavy rain that overcomes canals, vaults and come in forms of torrents or water excavation, with the promise of increasing the size and volume of infrastructure, there isn´t an integral and critical reading of the interrelation of issues. Climate change has shifted the source of recharge of water reservoirs since today only 35% comes from tropical melting glaciers while the rest 65% comes from pluvial precipitations, if the source of clean water supply has changed why hasn´t the system. “..the melting of tropical glaciers that was projected within the next 50 years, has accelerated and the loss of ice registered in this rhythm would reduce the environmental disaster within the next 20 years. (2)
The coverage of water supply in the city reaches to 93% of the population while sewage system reaches to 70% (Epsas 2012). Within this 23% that is not connected to the formal sewage system 4578 housing units make use of septic tanks and cesspits, 1100 use river and creeks to discharge consumed water, 454 discharges on streets and 15 discharges to lakes and small wetlands (National official results of conducted census of housing and population 2012). These discharges that are not part of the formal sewage system are often part of unplanned settlements that establish on the periphery of the valleys. More over what results also quite interesting is that 8146 housing units get drinking water from public faucets, 6272 get clean water from rain , creeks, rivers and springs. In a more broader perspective Bolivia has managed to incorporate in its new Constitution (2010) access to water as a right. This transformation is product of many reflections discussed in workshops, and seminars but mainly due to strikes and public demonstrations that had their critical moment in the year 2000 in Cochabamba with the so called “water war”. “The unreliable and limited services resulting from the implementation of Centralized state and private water management institutions produced pandemic civil Unrest, which manifested itself public social protest.(3) An important characteristic of development plans in Bolivia is the contradiction of having a set of laws, norms and regulations that provide a solid legal platform based on a deep understanding of structural issues, such as water management, that compared to the instruments and vocation of the final outcome planning process and vision seemed to be diametrically 60
opposed. The city of La Paz is a clear example of this mismatch where the legal framework is not able to find the correct partner in the practice that can integrate and bridge current challenges such as water accessibility, climate change and the desired vision on water achieved finally in 2010. Hence the need of rethinking a more comprehensive water system that deals with both contradictions the first one : having a water supply system based on melting glaciers that only contribute with 30% and having increasing volumes of rainwater that don´t know where to go, and the second one: having an strong and innovative legal platform for water management and returning to traditional approaches for projects and plans. [1] Free translation, Fernandez Katherine, “Gestión integral del agua bajo la vision del acceso al agua como derecho humano”, Ciudades y Cambio climático, La Paz 2012. [2] Hidraulic and Hidrology Institute , Universidad de San Andrés, 2011, as cited by Fernandez Katherine, “Gestión integral del agua bajo la vision del acceso al agua como derecho humano”, Ciudades y Cambio climático, La Paz 2012. [3] Chan, A., Kahn, V., Scott, C., & Vetere, P. Bolivian Water Wars, 2007
hypothesis
Water flow system CURRENT WATER FLOW SYSTEM The current system of water supply was built having the melting layer as the main source of clean water, the melting water of the glacier is contained in 3 big reservoirs: and 2 small ones, the water is piped to water cleaning plants in which the water becomes drinkable. These three plants distribute drinkable water to 243 683 housing units in La Paz and some prevailing industry in the northern area. Consumed water (dark and grey) from housing and industry goes to the two main rivers of La Paz Choqueyapu and Orkojahuira that act as collectors. The flow of consumed waters share the canalized rivers and the open creeks as a single drainage system, this means that there is no distinction between water from creeks, from rain, dark water, grey water and water from industry that doesn´t receive any treatment. The degradation of the quality of water in the river starts with industrial discharges at the entrance of the river, while the degradation of the tributaries of the main rivers, starts been polluted in the peripheral urban areas. Creeks that initially arrive with clean water (blue) soon become sewage in the new areas (yellow), once the creek or river is canalized this water flow becomes orange. When reaching to the central areas of the city, creeks and river go definitively under vaults and are considered the formal sewage where it already shows high pollution (red). Later on when urbanization stops the canals and vaults disappear, the quality of water improves (returning to orange) yet is not good enough to irrigate the agriculture fields down stream, production that later is sold in markets carrying diseases.
CURRENT WATER FLOW SYSTEM CLIMATE CHANGE SCENARIO With climate change the current system presents increasing flaws, first of all since an important part of the melting cape has drained, the reservoirs depend only 35% of this source, the remaining 65% comes from precipitation, the systems of reservoirs were not intended for water rain caption hence they are adapted to the new source. Since adaption of the system depends uniquely on the rainy season, during the dry season there is water shortage. With heavier rain and a lack of control over water, unplanned settlements in the periphery are vulnerable to suffer landslides caused by water infiltration and water excavation. Although river and creeks temporally improve the quality of their waters because of the increasing amount of water coming from the rain, the canals and vaults run the risk of being overwhelmed by torrents causing flooding and infrastructures damage. The most vulnerable place is downstream, crops that are being cultivated are flooded and the production on the fields is damaged during the rain season. The formalization of rivers as the main water drainage means that the system does not only have to bear with the volume of water coming from the natural system but it has to cope with the consumed water flow from house holds and the extra volume of rain derived from climate change.
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62
WATER SUPPLY/SEWAGE COVERAGE
Public authorities estimated that by 2036 100% of the population in La Paz will access both services water supply and sewage, meanwhile the conditions show that currently 93% of the population has access to drinking water, while 70% are formerly connected to the sewage system.
This figures show that there is still an important number of people who rely on alternative systems apart from the one provided by the city. According to the national census of 2013 out of the 243 683 households, still 17 354 use alterna-
tives methods to get clean water such as: from rain and creeks 6272, from public faucets 8146 and from wells, ponds and lagoons 2942. Regarding sewage system out of the 243783 documented housing units, 205211 of them have a connection to the formal sewage while 4578 claim to discharge into septic tanks, and 1100 into creeks and rivers. In order to look for design strategic logics it is fundamental to acknowledge the potential of vernacular practices that are currently dealing with water supply and water discharge. 63
“These knowledge and Andean wisdom are still kept involved in the among the daily practices of many people that dwell in zones of the city of El Alto and on the slopes of the city of La Paz as a result of the continuos flows and bonds of inmigration citycountryside and that are […] or could be , if not already, an alternative to adapting to climate change” (1)
[1] Free translation, Ichuta Jose Luis, “Lo que hacían nuestros abuelos”, Ciudades y Cambio climático, La Paz 2012
WATER SUPPLY COVERAGE SYSTEMS
WATER SEWAGE COVERAGE SYSTEM
64
PROPOSED WATER FLOW SYSTEM The proposed system aims to divert the courses of clean water, store and filter rain water, separate grey and dark water, implement properly treatment of industrial residual water and dark water., in addition to convey complementary strategies that are expected to close cycles and have a more efficient metabolism. The proposed flow starts by enlarging one of the cleaning plants and transforming it into an industrial treatment plant, this plant does not only treat industrial water properly but also separates the metals of the industrial water and extract the metals for reuse. In the periphery of the city the course of creeks are diverted to benefit from their good quality, the flow from creeks is also fed by rain that is captured in small ponds, this water can be used for washing, for the supply toilet even for bathing. In addition to the formal water supply system, that may or not be available in the periphery, tanks for rain water storage are implemented in houses in order to be filtered becoming ready for human consumption or as part of the clean water course. This strategy is also to be implemented in the rooftops of the more formal high rise buildings. Additionally the grey water is separated in these more formal typologies where there is more range of regulation, these flows from grey water can be used for irrigation of parks and humid recreational areas and finally join the main course of rivers. On other peripheral areas where some of the 23% of people with out sewage is expected to be, dry toilets are to be implemented were Humanure can be collected and sold to the farmers downstream as natural fertilizer. Water tanks for collection of rain are also implemented and creeks water flow are diverted. It is also important to intervene in the core of the flows, were river valley voids are to be transformed into cleansing forest ponds, that allow to depollute water and slow down the current. By creating a system of water flows that allow to reduce volume of water and pollution downstream, agriculture production is to be improved while creating new opportunities to deal with water accessibility and adaption to climate change in a sustainable framework.
65
66
hypothesis
Meshing water flows
CURRENT WATER FLOW DIAGRAM
The diagram represent the current flows in which the many discharges increase the volume of a centralized linear system where the central line is the Choqueyapu River. All the flows contribute to this single centralized linear system, here pluvial water, consumed water, industrial water and water from creeks and rivers is collected in a unique central sewage. This unique canal presents a highly contaminated flow of water represented in red colour, as households and industry contribute with residual discharges deteriorating rapidly 67
the good quality of water in creeks represented in colour blue. The volume of water is been added in a canal that was originally a river causing saturation in the system. Hence the final outcome is a massive orange line that is representing the final volume of water poured into the system together with a very contaminated water quality.
CURRENT URBAN GROWTH
Urbanization has extended its growth following the main tributaries, these tributaries have become central drainages as well, creating a linear configuration of the city.
mary until what point inhabitants of La Paz will abuse of a place that historically was not good enough for a stable and balanced urban development? “(1)
As the urbanization keeps extending its branches the city gradually loses its compactness and becomes a line that will keep consuming space of the rivers.
[1] Free translation, VillagĂłmez Carlos, La Paz ha muerto, La Paz 2004.
“Considering the magnitude of the projected numbers for the XXI century and the present problems, it becomes relevant to ask in the epilogue on which areas potentially [and currently] used for agriculture will we build? In sum68
HYPOTHESIS GENERAL STRATEGY
The general strategy aims to create a network of water flows, that can act as a grid: distributing the volume of water poured into the central canal, but also diverting the clean water from the polluted one. By creating a new network of water flows we designate smaller elements on which the flow is solved. As the diagram becomes a discrete representation of the problem., diverting the clean water from the more polluted one, and connecting this flow to similarly flows becomes part of meshing water flows. 69
This water grid not only performs as an engineering principle but also cooperates with nature and values the community sense of sharing clean water that is to become the main public space. It is by its nature incremental , this reduces costs for water a long term infrastructures.
RETENTION STRATEGY
As a complementary strategy retention of water results fundamental for reducing the volume of discharge in the main canal, as represented in the diagram the volume of water in the central canal is expected to be reduced by the implementation of clean water ponds. Diverting creeks with unpolluted water along with the creation of new water ponds and small canals of water serve also as the first source of clean water supply, taking into account that the creation of ponds and water canals is part of the vernacular practices in some 70
areas of the city. “What are uma k´otañas? They are small concavities that are created in the surface of the terrain with help of pickax and spade, their main function is to store water from rain or creeks. (1)
[1] Free translation, Ichuta Jose Luis, “Lo que hacían nuestros abuelos”, Ciudades y Cambio climático, La Paz 2012
CLEANSING STRATEGY
Apart from the retention of water and the new water flows mesh, it is important to work in the core of the most polluted areas of the linear canal. This purpose is tackled by slowing down the speed of the contaminated water flow and store it in bigger ponds in voids where natural system such as cleansing forests can be implemented. The quality of the proposed phytoremediation forest varies depending on the opportunities of possible flooding areas along the central canal.
71
These could be in the middle, next to it or along a confluence. The main criteria for this strategy to take place is finding the urban voids in which these decentralized voids along the primary course of the river can reduce the discharge of pollutants thus restoring ecologically the polluted stream.
STRUCTURE FOR NEW URBANIZATION
Finally new and more resilient urbanization is expected to be onwards guided by the reconfiguration of the new structures. In addition it is expected to reduce the volume of water in the main canal by having a new water network capable of retaining water along with new urban typologies. New resilient tissues with high density typologies that are both capable of providing enough housing and at the same time inserting themselves among water course system and valuing it..
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Lastly a significant decrease in the pollution of water courses is achieved, water accessibility is increased within a climate change scenario. The water is everywhere again.
micro story
73
Map of the upgraded areas and the lines of “Teleferico” system
S
trong actions have taken place in the city of La Paz along with a visible improvement in other areas such as security, participation, education, etc. These changes are widely seen as positive and were led mainly by two consecutives mandates of the mayors Juan del Granado and Luis Revilla, from the same political party which allow them to recover municipal authority 20 years ago and implement several important projects 10 years ago. The national government has also steeped in the change of La Paz by implementing the “Teleferico” lines, a cable car system meant for massive transportation alternative. May be the most important transformation started already in 2002 when the municipal government along with international partners such as the world bank invested in a significant informal settlement upgrade, that aimed to be as integral and as active as possible meaning not only an improvement of the urban environment, but also an important process of engagement with local actors and neighbourhood boards
through workshops and meetings . The key aspect of this project does not rely in a single transformation sample but it rather constitutes as a permanent simultaneous improvement that up till now keeps upgrading new neighbourhoods.
self regulated system the quality of transportation is irregular having unreachable areas and lack of accessibility during peak hours. The new bus system aims to provide effective displacement within peripheral areas and the city centre.
“46 zones of the laderas have been transformed under the project of Barrios de verdad through integral projects of improvement of which 39.157 inhabitants benefited..” (1)
In the year 2014 the cable car system Teleférico was implemented, this important infrastructure has two lines connecting La Paz with El Alto (and some of the most un favoured neighbourhoods on the west slope) and one of these also connects a residential zone of the centre with the southern zone where most of the new urbanization is. Another five lines are to be implemented in the city adding a new way of displacing. La Paz is experiencing an important moment public authorities with major support have taken the initiative, yet the field of urban design and urban planning is still waiting to step in and contribute to this important stage. The result is that these strong actions have changed the way of living in the city.
In the year 2011 a three stretch bridge was inaugurated in order to connect the dense tissues in an area where of three important river valleys become one. The big infrastructure is conceived under the rooted urban practice of articulation by bridges where the car has become once again the guide for developing such vital connections, although an important flow of pedestrians make use of the stretches that link very different areas of the city. In the year 2013 the municipal government implemented a new bus system that aims to improve the mobility conditions as the existing public transport constitutes of selfemployed and unions. Because of this 74
[1] Free translation, Publication of the Municipal Government of La Paz, La Paz 2011.
Mount Illimani the symbol of La Paz
Water urbanism a resilient opportunity for the reconfiguration of the city
design
New urban structures
CURRENT HYDROLOGY
0
2km
The current hydrology is the result of a progressive domestication of the creeks and rivers in order to give rise to urbanization, the hydrology is a discontinuous structure, that guided urban growth, by reducing its size and providing its natural flows. The performance of the hydrology for such different use needs to be strengthen and recalibrated.
PROPOSED HYDROLOGY
0 The new p roposed hy drology performs like a mesh, a grid allows water to follow different paths. The branches of the hydrology respond to sometimes restored old connections, close sources or same level confluents. Urban voids become opportunities for course to recover space, therefore these voids become either ponds or floodable areas. River restorations, not only ecological restoration but also in terms of form
2km
and performance along with clean water course ditches, retention ponds and rain water storage in buildings build new the blue structure of the mesh.
design
HYDROLOGY FLOWS 0
2km
The direction of water is defied by topography, the new canals and streams considers the change in the altitude to let gravity play in favour. The direction flows follows the natural course , the restored natural course, a parallel course of the same plain and the most ambitious course follows curves of levels, which allow to connect important main courses.
Pampahasi forest Pura Pura forest
PROPOSED GREEN STRUCTURE
0 It is expected to generate a vegetal secondary structure that follows some of the new courses of water. This green natural structure also contributes to the performance of the mesh, creating corridors of forest along clean water courses, and becoming the elements to slow down the current in main courses and de-pollute contaminated streams, parks and new natural areas within the city are irrigated by grey water from housing becoming receptors of this
2km
water flow. The only two exsisting patches of forested areas in La Paz: the fores of Pura Pura and the Pampahasi forest become part of the new structure.
design
PROPOSED URBAN STRUCTURES La Paz as a city settled in a difficult geographical condition of valleys, creeks, rivers and slopes, the amount of pressure on habitable land is huge, this is readable in the lack of open space. Due to the excessive attention paid to the urbanized centre of La Paz, the new blue and green structures intervenes in a larger scale prioritizing peripheral or secondary elements (such as rivers, patches of vegetation, slopes, curves levels, creeks) and where urban voids are only part of a major network. By taking advantage of these often forgotten secondary elements the new mesh explores the possibility to add a natural layer that performs according to the water related pressing issues, but also aims to re-introduce open space to an already overcrowded built environment..
0
2km
design
Blue structure
Clean water course ditch
Retention ponds
Rain water storage River restoration
RIVER RESTORATION
CLEAN WATER COURSE DITCH
RETENTION PONDS
RAIN WATER STORAGE
design
Green structure
Forest corridor
Phyto remediation Parks and new natural areas
PHYTO REMEDIATION
FOREST CORRIDOR
PARKS AND NEW NATURAL AREAS
design
BLUE STRUCTURE
GREEN STRUCTURE
GREEN + BLUE STRUCTURE
The two proposed blue and green structures interplay meshing flows of water., allowing to have a wide range of intervention that focuses as much as in the congested city centre as in the unflavoured periphery.
design
Clean course of water defined by curve of level contained within a forest corridor encircles an unplanned settlement, providing a source of clean water gathered from rooftops, rain and creeks. This infrastructure becomes public space in which community activities take place.
In the core of the city urban voids perform within a larger scale and become a fragment of a major structure. In this image a riparian forest mimics natural restoration of river; it slows down current and restores the polluted stream.
design
New urban areas learn from the flaws of previous models of urbanization, by integrating firstly to the natural conditions of the river, maintaining the vital activity of agriculture for the city, and lastly providing new typologies capable of dealing with housing demand and sustainable use of water systems that can be easily plugged in the restored water mesh system.
La Paz is a city originally settled on the course of high Mountain streams, therefore the rivers that sculpted the complex relief are the essence of this place, La Paz needs to become again a city of rivers, the city of the 300 rivers, not only because is part of its internal nature but because water is the most valuable resource to be preserve for the city´s inhabitants. Many rivers have been buried physically and metaphorically, therefore it is important to restore the living ones, and to give rise to new ones, a new water net work needs to flow again upon La Paz. The city is waiting for its water flows to be meshed.
references
Bibliography Acciavatti Anthony. Ganges Water Machine: Designing New India's Ancient River. Oro Editions, 2013 Amerasinghe Anojie, Dehaene Michiel. Matara: Structuring dispersion. Antilope Printers: Lier, 2007. Bolivian national comptrollers office. Report on the contamination of the catchment of the River La Paz. Chan, A., Kahn, V., Scott, C., & Vetere, P. Bolivian Water Wars, 2007. Constitución Política del Estado. Bolivia. Cuadros Alvaro. La Paz. La Paz, 2003. D´Auria Viviana, De Meulder Bruno, Shannon Kelly. “The Nebulous Notion of Human Settlements”, Human Settlements Formulations and (re) calibrations. Sun: Amsterdam, 2010. De Meulder Bruno; Shannon Kelly. Water Urbanisms East. UFO 3: Explorations of Urbanism. Park Books: Zurich, 2013. Estrada Liz , Propuesta técnica para la implementación de sistemas ecológicos de desinfección de las aguas del río Choqueyapu. Thesis presented to the faculty of industry engineering Bolivian Catholic University: La Paz, 2004 Fernandez Katherine, “Gestión integral del agua bajo la visión del acceso al agua como derecho humano.” Ciudades y Cambio climático. La Paz, 2012. Franken Margot. Gestión de Aguas, conceptos para el nuevo milenio. 2007. ICA Indice de calidad de Agua, Report on the contamination of the catchment of the River La Paz. Bolivian national comptrollers office, 2013. Ichuta Jose Luis, “Lo que hacían nuestros abuelos.” Ciudades y Cambio climático: La Paz, 2012. Mathur Anuradha, da Cunha Dilip. SOAK Mumbai in an Estuary. Rupa & Co, 2009. Medinaceli Ximena. “¿La Paz ciudad de cerros o de ríos?” Ciencia y cultura no 7, Universidad Católica Boliviana: La Paz, 2000. Revollo Daniel. “Contaminación del río Choqueyapu.” ABC Economía y Finanzas No 38: La Paz, 2003. Secchi Bernardo; Viganò Paola. Antwerp. Territory of a New Modernity. Explorations n.02. Sun: Amsterdam, 2009. Urquizo Carlos. Metrópoli Andina. Centro de Apoyo al Desarrollo Laboral: La Paz, 2004. Villagómez Carlos. La Paz ha muerto. La Paz, 2004. Wolman Abel. The metabolism of cities, 1965. *Publication of the Municipal Government of La Paz, La Paz 2010. *Publication of the Municipal Government of La Paz, La Paz 2011. * Hidraulic and Hidrology Institute ,Universidad de San Andrés, 2011, as cited by Fernandez Katherine, “Gestión integral del agua bajo la vision del acceso al agua como derecho humano”, Ciudades y Cambio climático, La Paz 2012.
Maps Bingmaps, 2015. First official map of the city 1796. Gerardus Mercator, 1569. Guaman Poma de Ayala, 1613. Google Earth, 2015 Imágenes históricas de Bolivia: La Paz, 1915. Lanza, Leonardo. 1877. M. Florentino Olivares 1880. Mesa Gisbert, The Spanish city century XVI, 1960. Maps of the National Territory, 1859: La Paz of 1846. Municipality official map, 1877. Sanson d´ Abbervile, 1652. Unknown. First settlements in 1548. * aerial photo 1950 (pag. 39)
Websites *GeoBolivia: http://geo.gob.bo/ (july 2015) *Gobierno Autónomo Municipal de La Paz: http://www.lapaz.bo/ index.phpoption=com_gmapfp&view=gmapfplist&Itemid=446 (june 2015) *Instituto Nacional de Estadística (INE) de Bolivia: http://www.ine.gob.bo/ (july 2015) *Ministerio de Medio Ambiente y Agua: http://mmaya.gob.bo/ (june 2015) *Fotos antiguas La Paz: https://www.facebook.com/groups/552392304808975/?fref=ts (august 2015) Photos *The northern valley of La Paz 1915 before rapid growth at the end of the century (pag. 22) https://www.facebook.com/ groups/552392304808975/?fref=ts *Engraving of the main Plaza of La Paz, 1877 (pag. 34) http://www.delcampe.net/page/item/id,115715813,var,GRABADO-GRAVURE-DU-1877--La-Paz--Bolivia--Vista-de-la-plaza-principal--De-fotografia,language,F.htmlEngraving of the main *Plaza of La Paz, 1880 (pag. 34) http://books.openedition.org/ifea/6085?lang=it *Train crossing the river, early XX (pag. 36) https://www.facebook.com/groups/552392304808975/?fref=ts *Water excavation caused by the river, tram lines hanging. 1933 (pag. 36) https://www.facebook.com/ groups/552392304808975/?fref=ts *Choqueyapu river before Avenida Montes, early XX (pag. 36) https://www.facebook.com/groups/552392304808975/? fref=ts *Vaulting the river opening Avenida Troncal 1935 (pag. 38) https://www.facebook.com/groups/552392304808975/?fref=ts *Choqueyapu canalized, before Avenida del Poeta , 1960 (pag. 38) https://www.facebook.com/groups/552392304808975/? fref=ts * Aerial photo 1950 (pag 42) https://www.facebook.com/groups/552392304808975/?fref=ts * Proposed new image (pag 89) adapted from Pablo Villalobos http://www.panoramio.com/user/4942325 Special thanks to Miguel Irigoyen and the collaborators of the Facebook group “Fotos Antiguas La Paz”. Interested parties for photo credits contact manuel.aliaga@yahoo.com