MITIGATING LANDSLIDES MEDELLIN, COLOMBIA
Grant Murphy
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LANDSLIDE SUSCEPTIBILITY
INTRODUCTION Objectives The goal of this section is to 1. Understand why I chose to research landslides af fects on informal settlments 2. To understand the complexities of landslides and how they work 3. To recognize and identify anthropogenic influences on landslides 4. To understnad the two different opportunities when it comes to solving landslides and 5.To gain a base knowledge on Medellin, Colombia.
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“Whoever has two tunics is to share with him who has none, and whoever has food is to do likewise.” Introduction Throughout college, I had the opportunity to travel to two Latin American countries, Peru and Panama. In Peru, I was part of a missionoriented team that spent nine days travelling to multiple villages throughout the Amazon regions the country. This experience was as eye-opening for me as I could ever hope it was for the people that we encountered. As I came into these villages, I encountered a people that lived the most basic of lives imaginable. These people lived day in and day out on what they needed to survive. As I stepped off of the thatched roof boat, I saw old men, hunched over on bar stools playing poker with the local sheriff. I saw dozens of kids sharing one soccer ball on a field consisting of a dirt road and makeshift goals. In each house, the women were preparing a dinner of fresh caught fish out of the Amazon wrapped in banana leaves and being smoked on a make shift grill. As I walked around town these people, who from an American perspective, had nothing. There
was not logical system of government, no real hierarchy of power and what seemed to be no formal set of laws. However, there was an incredible sense of culture. These people, no matter how impoverished the were, gave their town a sense of place. To them, this is not some far off mission field, which they would leave in two weeks. Rather, it is home and they are proud of to call it such. Children would come out of no where, grab my hand, and take me around their town, showing off where they go to school, where they hangout, and where there friends played soccer. Mothers would show off their home by preparing elaborate meals with the freshest of ingredients in which they would work all day making. One particular township even turned on the electricity for the first time in months, so we could enjoy their town at night. These experience taught me many things, but the chief of which is that no matter how unglamarous the housing conditions may be, it is still somebody’s home, it is still someone’s culture. It is my goal, through this project to begin to address how we might protect impoverished people groups from natural disasters as well as from being completely uprooted from their original location.
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Background Impoverished communities typically can not do much in the way of protecting themselves from natural disasters. For obvious reasons, most of their income goes to basic necessities such as food, shelter, and clothing. What this project hopes to address is social, environmental, and infrastructural dilemmas of impoverished communities in landslide prone areas.
“Landscape architects trained to analyze and intervene in situations with complex natural and social territorial dynamics are in a position to make positive contributions to managing risk in such situations.”1 -Shifting Grounds
Landslides are global phenomena; they happen throughout the world and are in no way limited to impoverished communities. However, landslide-prone areas are typically not settled in ‘First World’ countries because
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Children playing in the streets of a village in the Amazonion regions of Peru
of zoning laws and the vast availability of land. However, this does not always reign true. In 2004, a landslide in Washington State killed 43 people and covered an area of roughly one square mile.2 However, this magnitude of catastrophe is rare in America and other ‘Developed’ countries across the world. I am not claiming that we can completely stop landslides, but rather I am hoping to mitigate the anthropogenic influences which increase the chance of landslides. The Need Over the course of 7 years, 2,620 non-seismic landslide events have claimed over 32,000 lives worldwide, many of which have affected impoverished communities.1 Although landslides are a natural process, human influence greatly increases the chances for the global phenomena through the loss of vegetative cover, over development, lack of proper drainage and a lack of respect for natural processes. ‘Landslide’ has become an overarching term for all types of mass movements, in this book, they will be used interchangeably. However, there are two main types of mass
movement: gradual and rapid. Most steep sloped mountains ‘creep’ at a minimum of a few millimeters each year, which constitutes the gradual mass movements.4 Rapid mass movements are much more dangerous and can occur without any warning. Rapid mass movements include rockfall, slump, and debris flow. This project will focus on two primary forms of mass movement: slump and debris flow. A slump is ‘a type of slide that separates along a concave surface...the material within the slump tends to move as a unit and not become mixed’.4 Typically a slump will occur when a layer of permeable soil sits on top of a layer of impermeable soil. Once the permeable layer becomes over saturated, it has the potential to fall at any time. The two main types of slump are block slump and rotational slump (See page 10).
Figure 01
A debris flow is the most rapid of the two. A debris flow typically contains vary sizing of rock, debris and soil that liquefy and then run out of bowl-shaped depression. 5 As the soil leaves the source-bowl, it runs rapidly down hill, carrying anything that stands in its way with it. Once the water-saturated material reaches a flatter area, it will all come to a halt and end in the deposition site. Depending on the size of the soil particles that make up the debris flow, it can reach speeds up to 35 mph (See page 10). 5 Landslides are caused by geological, physical and anthropogenic factors. This list presents two components that cannot be addressed by humans: geological and physical. Geological factors include elements such as weathered rock, permeable soils, natural disasters, natural erosion and natural deforestation. Physical elements might include immense rainfall, freeze-thaw soils, slope angle, shrink-swell soils, surface runoff, and groundwater changes. Both the geological and physical factors are naturally occurring and are not affected by human influence. However, the final of the three part, anthropogenic influences, is something we can affect. Humans increase the likelihood of landslides through deforestation, negatively affecting water flow, soil loading, mining, and vibrations.3 Each of these three sets contribute to the susceptibility of a site to a landslide.
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November 9, 2001 Kerala, India Casualties: 40
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March 21, 2003 Colombia Casualties: 10
November 22, 2001 Colombia Casualties: 23
Figure 10
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January 10, 2005 California Casualties: 10
March 26, 2004 Sulawesi, Indonesia Casualties: 32
February 17, 2006 Leyte, Phillipines Casualties: 1126
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Dember 05, 2010 April 14, 2011 Medellin, Colombia Manizales, Colombia Casualties: XX Buries Casualties: 14 Many Dember 08, 2010 August 8, 2010 Medellin, Colombia Gansu, China Casualties: 100’s Casualties: 1,287
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May 10, 2010 Saint-Jude, Quebec Casualties: 4
Figure 16
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June 16, 2013 Uttarakhand, India Casualties: 5,700
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December 13, 2014 April 28, 2015 October 1, 2015 Java, Indonesia Salvador, Brazil Guatemala Casualties: 32 Casualties: 14 Casualties: 220 Missing: 76+ Missing: 350 April 23, 2015 May 18, 2015 Badakhshan, Afghanistan Atioquia , Colombia Casualties: 52 Casualties: 78 Missing: 37
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November 13, 2015 Zhejiang, China Casualties: 38
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September 6, 2008 Cairo, Egypt Casualties: 119 June 11, 2007 Chittagong, Bangladesh Casualties: 123
January 4, 2010 Gilgit-Balistan, Pakistan Casualties: 20
August 9, 2009 Kaohsiung, Taiwan Casualties: 439-600
March 1, 2010 Beduada, Uganda Casualties: 100-300
February 20, 2010 Madeira, Portugal Casualties: 42
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March 22, 2014 Washington Casualties: 43
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May 2, 2014 Afghanistan Casualties: 350-500 Displaced: 4,000
August 2, 2014 Sunkoshi, Nepal Casualties: 156+
July 30, 2014 Maharashtra, India Casualties: 136 Missing: 100+
Timeline The timeline shows the severe impact that mass movements can inflict on both the landscape and people. The timeline depicted covers a sample of the major landslides over the last 15 years. There is no absolute cataolog that records all mass movements. As mentioned before, the areas landslides have the most impact is in impoverished communities where there is often no formal government. Because of
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October 29, 2014 Badulla, Sri Lanka Casualties: 100+ Missing: 100’s August 20, 2014 Hiroshima, Japan Casualties: 50
this, it is difficult to calcualte the fatalities as there is no formal census to track people. David Petley, a geologist at the University of Durham, analyzed data from 2004-2010. During this 7 year period the Durham Fatal Landslide Database (DFLD) recorded 32,322 fatal deaths from landslides.6 This number is starkly juxtaposed from many other fatality estimates, leading Durham to the conclusion that landslide fatalities are vastly underestimated worldwide.
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Slump landslide General Information [def.]-’a mass of soil breaks free and slides along a planar or curved surface’7 Slope-45-900 Speed-N/A Types-rotational and block crest slump block scarp
earth flow
Earth flow
General Information [def.]-’Water-saturated finegrained slope material that liquefies and runs down hill ’7 Slope-5-90 Speed-0.11-35 mph Types-debris flow and mudflow
bowl shaped depression
main track
deposition
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‘Natural’ Influences
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O
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EARTHQUAKE
soil conditions
Cause Shifts within the landscape that cause landslides
Depth, minerology, soil moisture, soil temperature
prolonged rain
shrink-swell
Causes permeable soils to become overly saturated and collapse
Shrink-swell conditions /Thaw-freeze conditons cause shifts in the landscape
steep slopes 45
Natural diaster
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The greater the slope, the more unsuitable to build and the greater chance for a landslide
Produce unanticipated shifts within the landscape that cause landslides
ANTHROPOGENIC Influences deforestation
Removal of deep rooted vegetation for logging or other purposes
mining
Disrupting the ‘natural’ tectonics of a site, as well as causing vibrations
soil loading
Constructing houses, roads, etc. and increasing the load on the soil
Vibrations
From machinery, nearby traffic, and consturction
excavation
Removal of soil to allow room for buildings, roads, etc.
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Minimal Intervention [def.] using minimal site-scale interventions to mitigate the increased chance of landslides examples reforestation, hydrologic restoration, soil restoration, educational information
Figure 19
Significant Intervenion [def] rebuilding the entire site from the ground-up using a highly engineered solution to mitigate the increased chances of landslides examples/sites rebuilding homes, planned townships, highly engineered soil stabilization
Figure 20
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Both minimal and significant interventions have advantages over the other. One preserves culture, while the other threatens to decimate it. One uses highly engineered solutions, while the other uses native materials. One uses a skilled labor force, while the other utilizes a local labor force. One offers structural protection, while the other offers surface level protection. Is there a ‘better’ solution? No, each situation is unique and requires a specialized approach. Let’s start with the minimal intervention. Figure 21
Minimal Interventions Minimal interventions offer unique opportunities that significant interventions cannot. Minimal interventions have the potential to use a local labor force and local materials. This gives the impoverished community an economic driver, all the while creating a safer environment. A few of the possible interventions include revegetating in a process known as green nailing (fig. 22). This process implements previouslyv identified shrubs or trees known for an extensive root system and plants them to counteract deforestation. Another example includes channelizing stormwater runoff and controlling the route of all post-consumption water. This prevents a portion of the stormwater from entering the groundwater table, thus helping to keep the soil from becoming oversaturated. This method in particular can benefit from the use of a local labor force (fig. 23&24). Other implementation can include retaining soil through bamboo check dams (fig. 21) and recycled tires (fig. 19)
Figure 22
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MOSSAIC is an organization that specializes in the implementation of small scale, minimal, site-specific interventions. MoSSaiC (Managment of Slope Stability in Communities) aims to not only engage the locals within the community, but engage policy makers, project managers and practicioners. The organization produced a 400+ page book that offers guidance on how communities can begin to address the daunting task of mitigating landslides. Rather Figure 24
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than offering a holistic design solution, the company describes the process of a succesful community based-landslide mitigation design.
Figure 25
Significant Interventions Significant interventions provide a more holistic approach. As a generalization, the significant interventions will provide a greater level of security and safety to the residents of the community. However, this comes a at cost. First, quanitfiably, it requires a specialized labor force, specialized equipment, and a lot of start up money. For example, Medellin, Colombia has designed a complete overhaul of the informal settlments along the periphary of their city. Putting aside any moral qualms with leveling neighborhoods, the design solution is estimated to cost $283 Billion US Dollars.
Figure 26
Figure 27
Figure 28
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Un-quantifiable is the cost of culture. Significant interventions typically will not respect what is already existing on the site. Rather, the significant intervention will take an engineers approach and only focus on their site boundaries and not what exists on the outside of the site.
Abstract On the edges of Colombia’s second largest city, Medellin, is a community of impoverished people vulnerably situated on the side of a landslide-prone mountain. We know that landslides are exacerbated by human interaction (Anderson). Therefore, my capstone will address the social, environmental, and infrastructural dilemmas of a particular community in Medellin. The goal of my project is to design a selfsustaining, resilient community in the slums on the outskirts of Medellin that provides solutions to mitigate and improve the economic and environmental conditions. My capstone will address a synergistic balance between combatting future landslide occurrences through interventions such as reforestation and hydrologic restoration, while providing a stable social and economic structure within the community.
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Medellin, Colombia The site is nestled in a valley of Medellin and is part of the Andean mountain range. Medellin is the second largest city in Colombia and is the top economic producer in the Antioquia Department (or district) and accounts for 69% of it’s GDP. The city is approximately 147 square miles and is located 5,000 feet above sea level. Colombia has an average monthly income of $692, which is less than 50% of the global average of $1,480.8 Medellin is a sprawling metropolis, rich with culture and setting the standard for revitalizing a city. In 1991, it was believed that Medellin supplied 80% of the world’s cocaine.9 Pablo Escobar, also known as ‘The King of Cocaine’, was a very clear representation of what Medellin used to be. Escobar was born in a quiet country town in southern Colombia, as a teenager, he moved to Medellin and began his criminal career. He started out with small acts such as stealing grave markers, but he quickly become one of the most notorious drug smugglers of all time. In 1989, after the height of his career, Escobar was recognized by Forbes magazine as one of only 22 billionaires in the world. They listed his net worth at $2 billion and his cash flow at $3 billion.10 Pablo ran his entire organization through the ‘Medellin Cartel’. It is believed that the people of Medellin often served as lookouts for him. Eventually, in 1933 Escobar’s lifestyle caught up to him and he was gunned down in Medellin. Legend has it that he turned the gun on himself and commited suicide, but no one can confirm either way. How did one man affect the fabric of a city? Greatly. In the 1980’s, Medellin was classified as one of the most dangerous city’s in the world.12 Escobar in essence ran the city, he controlled the slums and the government. Even if someone wanted to implement policy during this time to prevent the settling of steep-sloped mountain sides, they would
have to go through Escobar first. Escobar used the slums as hiding places for his money, drugs, and people, why would he want them gone? Along with Escobar’s death in the early 90’s, came the uprising of a great leader in the early 2000’s. Sergio Fajardo served as Mayor of Medellin from 2003-2004 and currently sits as the governor of Antioquia. In 2003, when Fajardo was first elected, he was a revolutionary for the city of Medellin. “Fajardo’s approach was based on sequential planning and strategic implementation of a number of projects that focused on education, cultural reform and social inclusion”.13 Fajardo used a sort of urban acupuncture to reach out and affect the entire community of Medellin. He identified the most dangerous areas of the city and wanted to change them. Rather than sending in the police and military, Fajardo decided to build library parks, schools, botanical gardens and much more. Just as one man, Pablo Escobar, negatively affected the urban fabric of Medellin, one man, Sergio Fajardo, positively changed the fabric of the city.
‘We regect the paradigm that, when it comes to poor people, any little thing will do-that they will be happy just to get anything at all” -Mayor Sergio Fajardo Since the late 19th century, landslides have accounted for over 750 deaths and 7800 critical injuries to peoples within the Medellin Valley.1 Despite the cities susceptibility to landslides, the population has grown over six times in the last 65 years, leaving the poorest communities in the most vulnerable areas. Colombia’s drug related violence is causing many locals to flee from the countryside and
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Medellin
to seek shelter in the city. As these people arrive, they cannot afford to live within the city itself and are forced to find a home in the slums along the steep mountainsides of the adjacent city. These steep-sloped mountainsides are rendered unusable by the landowners because no conventional use can take place in these areas. Although landslides are a natural process, human influence greatly increases the chances for the global phenomena through the loss of vegetative cover, over development, lack of proper drainage and a lack of respect for natural processes.
More than 50% of disaster deaths occur in low-human development countries even though only 11% of people exposed to hazards live there. 11 What Now? Medellin has taken great strides towards
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mitigating the drug and violence problems that once plagued their city. The city has proven itself to be a world leader by addressing the complex issues of informal settlements. Unlike many other cities, Medellin has not turned it’s back on the impoverished community, but rather began to embrace it by building metro cables to it and investing money into its urban fabric. It is the goal of this project to address Medellin’s potential in protecting it’s impoverished citizens by giving the people the tool’s needed to protect themselves. My research has shown that small scale interventions, implemented across a large scale site can greatly reduce the potential impact of landslides. However, is this the right solution? Medellin has drafted a plan known as ‘The Greenbelt’ which offers a completely different solution to ‘solving’ informal settlements.
URBAN FABRIC OF MEDELLIN19
Violence in the Countryside
Traditional Housing is Full
Urban Sprawl
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Dense Urban Sprawl
2,273,727
2012 population Growth Management in Medellin, Colombia
21%
of population live in slums
KTH Architecture
1300 ft.
elevation increase from the city center to the city limits
101,887
internally displaced people received in 2011
Growth Management in Medellin, Colombia
KTH Architecture
Growth Management in Medellin, Colombia
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Figure 30
The Greenbelt, or ‘Cinturon Verde Metropolitano’ offers a significant intervention-style solution. The Greenbelt offers a 72 kilometer solution to the entire metopolitan area of Medellin.13 At best, the solution is insensitive, but affective. At worst, the city is planning on destroyong tens of thousands of homes. The proposed solution will strip away a large portion of the culture in Medellin. The proposed section (fig. 30) offers a four part solution to containing urban sprawl while respecting the land around it. The highest band, the buffer strip, allows for ecological restoration. This band is abutted by a pedestrian corridor that includes bike lanes and a trails throghout the ecological corridor. The pedestrian corridor is followed by a transition strip that allows for public facilities and water mangement. This will allow for public recreation fields and increased slope stabilization. This band is followed by the mobility corridor which undoubtably will help to alleviate some of Medellin’s traffic condtion. It will provide a loop around the entire city. The final band is reffered to as urban consolidation. In this band, high rise residential towers are offered as a soltuion to all of the displaced people groups that were affected due to the implentation of The Greenbelt. 14
a great solution if there were not already people living in these communities. Implementing this stragey destroys homes, jobs, relationships and peple sense of safety
“The plan aims to address complicated issues of land squatting, barrio upgrading, governance, and ecosystem loss through one general proposal that does not adequately take into account issues at the local community level”14 Is there a way to do this without completely destroying the entire culture?
All of this sounds great, right? It does sound like Figure 31
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Citations In-Text 1. Joseph Claghorn & Christian Werthmann (2015) Shifting ground: Landslide risk mitigation through communitybased landscape interventions, Journal of Landscape Architecture, 10:1, 6-15, DOI: 10.1080/18626033.2015.1011419 2. Snohomish County Medical Examiner’s Office (July 23, 2014). “Snohomish County Medical Examiner’s Office Media Update”. Retrieved July 27,2014. 3. “What Causes Landslides?” Australian Government: Geoscience Australia. Web. 31 Jan. 2016. 4. Kuehns. “Mass Movement.” Washington & Lee University. Web. 31 Jan. 2016. <http://home.wlu.edu/~kuehns/geo100/ w10/landslides6.pdf>. 5. Girty, G.H. Perilous Earth: Understanding Processes Behind Natirual Diasters. San Diego University: Department of Geological Sciences. Print. 6. Petley, David. “Global Patterns of Loss of Life from Landslides.”Geology [Boulder] 40.10 (2012):927-930. GeoRef. Web. 28 Jan. 2016 7. Varnes D. J.: Slope movement types and processes. In: Schuster R. L. & Krizek R. J. Ed., Landslides, analysis and control. Transportation Research Board Sp. Rep. No. 176, Nat. Acad. oi Sciences, pp. 11–33, 1978. 8. “Medellin”. Encyclopædia Britannica. Encyclopædia Britannica Online. Encyclopædia Britannica Inc., 2016. Web. 31 Jan. 2016 9. McFadden, Robert D. “Head of Medellin Cocaine Cartel Is Killed by Troops in Colombia.” The New York Times. The New York Times, 1993. Web. 31 Jan. 2016. 10. Touryalai, Halah. “Watching Netflix’s Narcos? Here’s Pablo Escobar in Forbes’ First-Ever Billionaire Issue in 1987.” Forbes. 15 Sept. 2015. Web. 11. Anderson, Malcolm, et al. “Implementing Low-Cost Landslide Risk Reduction: A Pilot Study In Unplanned Housing Areas Of The Caribbean.” Natural Hazards 3 (2008): AGRIS. Web. 1 Feb. 2016.
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12. Drost, Nadja. “In Medellin, a Disturbing Comeback of Crime.” Time. 25 Feb. 2010. Web. 13. Devlin, Matthew. “Sergio Fajardo Valderrama.” Successful Societies. Princeton. Web. <http://successfulsocieties.princeton. edu/interviews/sergio-fajardo-valderrama>. 14. Retos Y Oportunidades Para Las Lderas Y El Cinturion Verde De Medellin Y El Valle De Aburba. Medellin: Universidad Eafit: Abierta Al Mundo, 2012. Print. 15. Barrows, Lisa, Lingjun Bu, Ellis Calvin, and Anne Krassner, Et al. Growth Management in Medellin, Colombia. New York: Columbia U. Print. Image Credits 1. news.bbcimg.co.uk 2. i.telegraph.co.uk 3. 100resilientcities.org 4. thehindu.com 5. thejakartapost.com 6. 7. primenews.com 8. msnbcmedia.msn.com 9. static-secure.guim.co.uk 10. inapcache.boston.com 11. news.bbcimg.co.uk 12. static-secure.guim.co.uk 13. thekeyofknowledge.net/ 14. images.indianexpress.com 15. newsfirst.lk 16. theupcoming.flmedialtd.netdna-cdn. com 17. i2.cdn.turner.com 18. blogs.agu.org 19. wp.preventionweb.net/ 20. dsiamerica.com 21. savethehills.blogspot.com/ 22. etivernetinternational.blogspot.com 23. mossaic.org 24. mossaic.org 25. jcbaldwin.com 26. jcbaldwin.com 27. worldlandscapearchitect.com/ 28. 29. chrisontour84.files.wordpress.com 30. w.arch.columbia.edu 31. w.arch.columbia.edu 32. w.arch.columbia.edu 33. w.arch.columbia.edu