Participatory Stormwater Management for Quito, Ecuador Ortega Watershed Demonstration Area By Ricardo da Cruz e Sousa
A professional project submitted in partial satisfaction of the requirements for the degree of Master of Landscape Architecture and Environmental Planning in Landscape Architecture and Environmental Planning in the Graduate Division of the University of California, Berkeley
Committee in charge: Professor G. Mathias Kondolf, Chair Professor John D. Radke Engineer Eduardo Flores, M.Sc.
Spring 2012
The professional project of Ricardo da Cruz e Sousa, titled Participatory Stormwater Management for Quito, Ecuador – Ortega Watershed Demonstration Area, is approved:
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University of California, Berkeley Spring 2012
Participatory Stormwater Management for Quito, Ecuador Ortega Watershed Demonstration Area Copyright 2012Š by Ricardo da Cruz e Sousa
Abstract Participatory Stormwater Management for Quito, Ecuador Ortega Watershed Demonstration Area by Ricardo da Cruz e Sousa Master of Landscape Architecture & Environmental Planning University of California, Berkeley Professor G. Mathias Kondolf, Chair
Ever since the 1970’s a significant portion of Ecuador’s rural population has moved to the Capital City of Quito. Urban expansion has encroached upon stream banks and steep slopes. These spontaneous developments negatively impact the natural water cycle, pollute water resources, cause soil erosion, landslides, and floods. Quito’s Water District, Empresa Publica Metropolitana de Agua Potable y Saneamiento (EPMAPS), has been investing in conventional systems of urban drainage. Engineered hard structures for debris control in the stream channel and conduits adjacent to stream corridors that intercept sewage from draining to the streams are the most common interventions, particularly in the southern urban edge. These structures are nevertheless stop gaps as the city continues to expand increasing the problems. An alternative solution to Quito’s drainage systems is Participatory Stormwater Management (PSM). PSM is inspired by the concept of Integrated Urban Water Management (IUWM) that is described as the practice of managing water supply, wastewater, and stormwater as components of a watershed management plan with focus on community involvement. IUWM seeks to reduce the impact of urban development on the natural water cycle by calculating the change between the natural, pre-development, water balance and the post-development water balance. The PSM envisions a community-involved process to incorporate sustainable stormwater control measures to mitigate changes to improve water quality, decrease surface runoff, and mitigate natural disasters. Through using a selected site in the Ortega Watershed as a demonstration project, this project explores the potential of PSM as a viable alternative to urban runoff that could be replicated in the entire watershed and other watersheds of the city.
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Table of Contents
INTRODUCTION VII CONTEXT 5 Quito’s Growth 6 Problems Related to Urbanization 8 Current Proposals and Solutions in Quito 9 Existing Drainage System 10 Existing Regulation 11 Demonstration Area 12 Land Ownership 15 BACKGROUND 19 Integrated Urban Water Management (IUWM) 20 Participatory Stormwater Management (PSM) 21 Stormwater Management in Humid Tropics 22 Stormwater Pollutants 23 Control Measures 24 Sizing Control Measures 27 Composite Runoff Coefficient (C) 28 The Importance of Community Involvement 29 Community Involvement in Quito 32 Orangi Pilot Project Precedent 34
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Table of Contents
OBJECTIVES 37 METHODS 40 Site Visits and Field Observation 42 Existing Flow Conditions 43 Satellite Imagery and Manipulation 45 PRELIMINARY DESIGN 51 Vegetated Swales 52 Detention Basins 55 COMMUNICATION 59 CONCLUSIONS 67 Results 68 Recommendations 69 GLOSSARY 71 REFERENCES 72
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INTRODUCTION
The development of the City of Quito, particularly on the south edge, has occupied creek banks and steep slopes causing the increase of surface runoff and peak flows. This is the reason for the deterioration of the overall quality of those creeks, the overflow of the city’s combined sewer system, floods, and other problems. Climate change will likely intensify the frequency and duration of rainfalls, generating even more runoff in cities and intensifying all the problems noted above. This is a concern for which cities must be prepared because expanding the conventional drainage systems is costly and just temporary until it reaches maximum capacity again.
Both photos from the Quitumbe Zonal Administration Archives. 1
Photo of flood consequences in the Ortega Creek, 2009.
This project proposes that an integrated approach to stormwater management can restore the water quality in the city’s creeks while minimizing risks from natural or human-induced hazards, such as floodings and landslides. These solutions restore ecological systems, carry social benefits, and improve the quality of life in the city.
Photo of flood consequences in the Ortega Creek, 2009.
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This is a project for Quito’s Water District, Empresa Publica Metropolitana de Agua Potable y Saneamiento (EPMAPS). EPMAPS has been working in improving the existing deteriorated conditions of the city’s hydrological cycle and environment. EPMAPS has been requesting comprehensive infrastructural studies to restore the western slopes of the Atacazo Mountain and the Pichincha Volcano, to manage the southwestern watersheds, and to prevent natural disasters. These studies cover only the conventional engineered solutions. Therefore, it is in the best interest of EPMAPS to study the application of feasible sustainable alternatives.
Integrated Urban Water Management (IUWM)
Participatory Stormwater Management (PSM) is inspired by the concept of Integrated Urban Water Management (IUWM). IUWM seeks to reduce the impact of urban development on the natural water cycle by calculating the change between the natural, pre-development, water balance and the post-development water balance at the watershed scale. The water balance comprises water supply, sanitation, stormwater, and solid waste. The latter is particular acute in developing countries due to the lack of a proper waste collection system that thus clogs the conventional drainage systems.
Participatory Stormwater Management (PSM)
Solid waste
2
Stormwater
The way to test PSM in the city’s policy and planning is to evaluate its feasibility. In order to do so it is necessary to use a demonstration area.
Wastewater
PSM is an application of this bigger concept that deals more specifically with urban runoff. It features sustainable control measures to mitigate changes to both quantity and quality of runoff caused by changes to land use. These measures have been applied in developed countries for years as Best Management Practices (BMPs), green infrastructure and Low Impact Design (LID) (in the United States), or Sustainable Urban Drainage Systems (SUDS) (in the United Kingdom), or Water Sensitive Urban Design (WSUD) (in Australia). These are just a few examples of different terminologies for the same basic concept of reducing urban runoff and increasing infiltration in such a way that looks to mimic the natural water cycle in the city.
Watershed level
water supply
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Proposing an alternative stormwater solution that slows, diverts and cleanses water instead of simply conveying it downstream can decrease the peak flow, reduce disasters, and improve the water quality. These are environmentally friendlier options to manage runoff.
The second trip was in January 2012. After collecting all the basic information on the first trip, maps, studies, GIS data, and photos, the goal of this second trip was to meet with the EPMAPS to present some design ideas and perform site analysis, such as percolation tests and field observation. This second trip lasted two weeks and proved valuable to synchronize the EPMAPS intent with my own. It was also useful to learn more about the city’s most recent hard-infrastructural solutions and about the study site.
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Photo by the Ortega Creek talking with local community members demanding an intervention. Nov 2011.
After the workshop I stayed for a few extra days to meet with the EPMAPS engineers, do some site visits, and further evaluate the problems. From this it became evident that a specific site within the Ortega Watershed would be an ideal demonstration area for a sustainable stormwater system.
Photo by the Ortega Creek preparing for a percolation test Jan 2012.
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During this project I visited Quito twice. The first time was in November 2011 for a workshop convened by EPMAPS about Green Infrastructures in Cities. For this workshop EPMAPS and local landscape architect and alumni from the Department of Landscape Architecture & Environmental Planning (LAEP) at UC Berkeley, Gustavo Gonzalez, invited specialists from all over the world to present their own experiences about these sustainable solutions. A group of faculty and students from LAEP was also invited to participate. In this workshop it was clear the curiosity of the EPMAPS, local institutions, and others, in the topic. As an exercise, the EPMAPS suggested several sites nearby creeks in Quitumbe for the participants to study a potential sustainable solution. The Ortega Creek was one of them.
The methods for this study are, identify the problems related to drainage of the area; analyze the current drainage system, propose an alternative sustainable drainage system and potential different uses for the areas of intervention; and propose a community engagement strategy. The objective is to study a preliminary design proposal that will serve the EPMAPS and a communication piece that will be used by the community organization, ACMQ Solidaridad. This proposal will be continued later this year in Quito, together with all the stakeholders and proceed to design adjustments and implementation by the community.
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Photo of the Ortega Creek.
The ecological and aesthetical values of the creeks are something appreciated by everyone. A stretch of the Ortega Creek was restored in recent years by the local community. Lead by the community organization, ACMQ Solidarid, to improve its environmental conditions and provide a recreational use. This is a strong evidence of the community’s interest in restoring their natural environment.
Photo of Ortega Creek stretch restored by ACMQ Solidaridad.
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The Ortega Watershed, a low-income peripheral area southwest of the city in the Quitumbe Zonal Administration (QZA), constitutes a good opportunity to test PSM, since it is a priority intervention area for the EPMAPS due to a continuing effort to restore the creek and work with the local community. The area grew rapidly, occupying areas of risk, such as creek banks that were filled leaving little room for the creek to perform its natural processes. Floods and other disasters are frequent and residents complain about the lack of sanitary conditions nearby the creek. The people’s first reaction was to request that the creek be culverted. That would inevitably lead to the occupation of the land above it. Carlos Tucci, author of several books on flood and stormwater management in cities in developing countries, mentions this fact in his work, and its reasons will be explored later, nevertheless, culvert the creek is no more than covering up the problem and not the solution for restoring the water cycle.
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CONTEXT
160
Quito is located in the Andes Mountains on the eastern slopes of the active volcano, Pichincha. Like many other cities in Latin America, Quito had an exponential growth since the 1970’s due to rural migration. According to the last census (2010) the city has a population of 2,239,191 people, 399,339 more than in 2001, corresponding to a growth rate of 2.18%. Between 1990 and 2001 the growth rate was of 2.42% (INEC). This is important data since it shows that the city, although at a slower rate, continues to grow.
140 120 100 80 60 40 20 0 Jan
Pichincha
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Quito’s average monthly rainfall intensity (black) compared to San Francisco, CA (grey) in mm.
Quito
Quito’s exceptional climate conditions reflect its particular geography. The city center is sited at 2,800 meters (9,200 ft) in elevation, making it one of the highest cities in the World. In fact, it is the second highest capital city in the world after La Paz (Bolivia). According to the Köppen climate classification, Quito has a subtropical highland climate (Peel et al. 2010). Because of its elevation and its proximity to the equator, Quito has a fairly constant cool climate, with springlike weather year-round. The precipitation regime is characterized by intense rainfalls almost every day for about 15 min. The monthly precipitation mean varies between 26.2 mm (1.031 in) in July to 149.3 mm (5.878 in) in April and the annual average precipitation is 1,010 mm (40 in), twice the precipitation of San Francisco, CA (see graph). Although, the south side of the city, at highest elevation, has highest values of average precipitation, up to 1,600 mm (63 in)(INAMHI).
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Photo of common rainfall in the city of Quito.
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Quito’s Growth
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1760 1921 1956 1983
Quito’s growth since the European settlement. The red square represents an area of 16 km2.
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1987 Today
Problems Related to Urbanization Post-urbanization
Discharge
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These volatile weather conditions create several issues related to urban drainage. Poor water quality, landslides and floods are concerns of the local authorities. Therefore they have been implementing during the past years expensive engineered hardinfrastructural solutions to minimize these problems.
Pre-urbanization
Time Hydrograph showing the highest peak flow and shorter lag time of the post-urbanization condition.
Modifications of land surface during urbanization produce changes in the type or magnitude of runoff processes. The major change in runoff processes results from covering parts of the watershed with impervious roofs, sidewalks, roadways, and parking lots (Dunne and Leopold 1978). Standardized urban infrastructures such as gutters, drains, and sewers convey water rapidly causing stormwater to accumulate downstream more quickly producing high flood peaks. Even if the total volume and peak rate of runoff from the land surface were not increased by urbanization, which of course they are, the increased velocities in the channels would still decrease the lag between rainfall and runoff (Dunne and Leopold 1978). The consequences of this change are a decrease of water quality, because runoff flushes down litter and pollutants from streets to receiving water bodies, an increase of floodings, landslides, and erosion. In cities in developing countries the main problems related to urbanization are predominantly caused by fragmented approaches to development and lack of capacity to effectively manage the rapid growth of unplanned settlements. Urban master plans do not generally take into account all infrastructural components related to urban water management. As a result, outputs are poor with few indicators of efficiency (Tucci 2007). The majority of water supply and sanitation services in cities in the humid tropics do not take into account all the components of the urban water cycle. This results in the connection of sewers to the stormwater drainage system; a lack of, or inefficient wastewater treatment; flood increases due to lack of capacity in the combined sewer system; excessive losses in the water supply network; and solids in the drainage system (Tucci 2007). 8
In 2010 another study, Plan de Manejo Integral de las Laderas del Eje Pichincha-Atacazo (PMILEPA), looked at the urban development on the slopes of the Pichincha-Atacazo axis, identified several problems, and presented some long term plans and projects to deal with this illegal occupation. One of the plans concerned the management of Quito’s watersheds. This plan is part of a general land use plan for the entire metropolitan district due to be complete by 2025. Both studies highlight the causes for the city’s problems in the past few decades related to urban growth, such as occupying areas of difficult access, steep slopes and river/creek banks. They also set basic infrastructure as one of the goals that needs to be achieved in these urban expansions, as well as, risk reduction and the mitigation of negative effects on the environment. The main concern of the local authorities is to improve the living conditions in these communities. Channels, conduits, pipes, and other conventional solutions to convey water as fast as possible have been implemented all over the city. On the west side, up the slopes of the Pichincha volcano, even dams were built to prevent flood hazards in the city center. These are still, in the decision-makers and technicians minds, the only solutions. But the lack of understanding of the natural processes and the problems of urbanization is reflected in the prevelance of these solutions and has implications on the general efficiency of the systems.
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Photo of hard-infrastructural solutions in the creeks.
In 2009 the study, Protección de Laderas, Cauces y Colectores de las Cuencas Comprendidas entre las Quebradas Sunipamba y Saguanchi (PLCC-SAFEGE), requested by EPMAPS, considered the execution of more hard-infrastructures to minimize risks of disasters, and set ground to rehabilitate some specific neighborhoods on steep slopes and creeks in the south side of the city and therefore protect the city center located downstream.
Photo of litter deposited by the creek.
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Current Proposals and Solutions in Quito
There are basically two types of sewer systems, the separate storm sewer system and the combined sewer system. The conventional separate sewer system does not provide any stormwater treatment. The biggest concern regarding stormwater treatment is to remove specific pollutants and treat what is known as the “first flush�. The first flush is the dirtiest runoff, usually generated during the beginning of a rain event; it mobilizes the majority of the pollutants and debris that have accumulated on impervious surfaces since the last rain. Combined sewer systems also treat most urban runoff, including the first flush and most additional stormwater runoff. However, when the capacity of the system is exceeded by larger storm events, localized flooding and combined sewer discharges (CSDs) can occur. In the event of a CSD, the system discharges a mixture of partially treated sanitary effluent and stormwater to receiving water bodies (Beaupre et al. 2009). There’s also a problem of understanding the function of this system. Litter frequently accumulates by creeks, storm drains, and other drainage structures, causing obvious inefficiency of the drainage system and pollution of the water. The community needs education about the natural processes and the importance of such systems.
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Photo of litter accumulated by storm drain.
Most of the city of Quito is served by a combined sewer system but some areas of the urban periphery lack of any sort of stormwater or sewer infrastructure. In these areas stormwater flows directly to creeks without treatment and wastewater is flushed out to septic tanks. The combined sewer system conveys wastewater and stormwater in the same pipes. The combined flows will then receive treatment at wastewater treatment plants before being disposed of back to the creeks. This is currently being implemented by EPMAPS as part of their strategy to improve sanitary conditions in city expansions. However this proposal will demonstrate that there is a better and more economical way to treat stormwater. This analysis of the existing conditions is essential to determine what types of stormwater management goals can be achieved.
Photo of litter in drainage trench.
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Existing Drainage System
There is no water legislation in Quito except water quality regulations. There are specific water quality parameters for different uses that are established by national environmental law, Norma de Calidad Ambiental y de Descarga de Efluentes: Recurso Agua. The only related legislation that affect this project concerns land use, particularly adjacent to creeks. According to the municipal regulation, the creeks must have a protection buffer depending on the creek’s morphology. Thus, Art. 57 of the Ordenanza Municipal 264, reviewed in December of 2008, entitled “Areas of protection of creeks” states: In creeks there should be the following areas of protection and conditions: a) In creeks with slopes smaller than 10 degrees, the area of protection will be of 6,0 m in horizontal longitude measured from the upper edge of the creek; b) In creeks with slopes bigger than 10 and smaller than 60 degrees, the area of protection will be of 10,0 m in horizontal longitude measured from the upper edge of the creek; c) In creeks with slopes bigger than 60 degrees, the area of protection will be of 15,0 m in horizontal longitude measured from the upper edge of the creek; d) The upper edge of the creek shall be determined by the Dirección Metropolitana de Catastro. In the definition there should be mentioned the slope information of the creek in degrees and percentage for each parcel and will establish the limit of the zoning for the protection of the creek. Nevertheless, the land adjacent to creeks is often occupied by illegal developments, some settled from many years back. The law in Ecuador states that if a piece of land is occupied for more than 15 years without dispute the resident gains right to that property. This is the situation in many of the properties adjacent to the creeks in Quito where properties have been passed to second or third generations and is now difficult to negotiate the eviction of these families. 11
Photo of building adjacent to the Ortega Creek.
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Existing Regulation
Quito is divided into 8 zonal administrations and 32 urban parishes. The demonstration area is located in the south side of the city in the Quitumbe Zonal Administration (QZA). Quitumbe has a population of almost 300,000 and by 2001, 38% of the population lived bellow the poverty line and 16% lived in extreme poverty conditions (SAFEGE 2009). The organizational structure of the neighborhoods, supported by the QZA, involves specific neighborhood policies, committees of public safety and neighborhood sports leagues. Some of these neighborhoods are still in the process of legalization, but nevertheless are pretty consolidated with leaders that constantly defy the authorities and pressure the local government. A typical character in these neighborhoods are “developers� or land dealers, who by not respecting municipal ordinances and exploiting the need of the residents, encourage the illegal status of large sectors of the population. The cohesion levels in the neighborhoods are low, which is a factor that increases the risk, since prevention and immediate response to disasters are limited. Finally, the poor management of solid waste from the population as well as the collection and disposal from the city are aggravating factors of risk and vulnerability of the area.
City of Quito. The red square indicates the area of Quitumbe.
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Demonstration Area
Table with data from SAFEGE 2009.
Parishes of Quitumbe
Nr of Houses
2001 (hab.)
2010 (hab.)
Hab/ Ha (in 2010)
Potable water
Solid waste collection
Sewers
Guanami
11.305
39.101
56.821
42
50.5%
76.7%
68.3%
Turubamba
9.396
31.493
58.675
39
41.1%
79.6%
73.0%
La Ecuatoriana
11.126
40.147
52.476
22
76.7%
87.2%
81.6%
Quitumbe
11.466
38.113
78.915
71
74.5%
87.3%
75.6%
Chillogallo
11.591
42.585
44.553
29
77.3%
90.2%
85.0%
Total
54.884
191.439
291.439
262
65.5%
84.6%
77.1%
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Location of the demonstration area. The red line limits the Ortega Watershed.
Following the EPMAPS and the QZA request, the EPMAPS chose an area upstream from the previous community intervention to demonstrate an alternative system of stormwater management. The idea is to develop a proposal that the EPMAPS and the QZA can pass on to the local community organization and involve the community in further planning, designing, construction, and maintenance of their own stormwater system. For years the local community has suffered from poor water quality in the creek, a degraded environment, and floods. The community members are demanding that something must be done to improve the creek. Therefore this is an high priority intervention area for the city’s decision-makers. There has been several requests from the QZA on behalf of the community to restore specific places along the creek within the area, but denied by the City and the EPMAPS because of the high level of contamination of the water making it a serious public health problem.
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Aerial photograph of demonstration area.
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As noted above, the most effective way to deal with stormwater management is to plan at a watershed scale. The EPMAPS and the QZA are working with local communities to restore some local creeks. The Ortega Creek has an emblematic community restoration project that the EPMAPS and the community organization ACMQ Solidarid are proud to display. This intervention is located at the downstrem edge of the Ortega Watershed (top right corner of the side photo). The EPMAPS, in the person of its current General Manager, Eng. Othon Zevallos, is promoting the idea of continuous interventions along the city’s creeks, revitalizing and tranforming them into healthy green corridors. This vision was born when Othon Zevallos was in charge of the Environmental Sanitation Program of the EPMAPS, Programa de Saneamiento Ambiental (PSA), that deals directly with many of these new interventions in the creeks on the outskirts of the city, in particular up the slopes of the Pichincha Volcano and the Atacazo Mountain.
The problem with this solution is that the interceptor will convey the water from the combined sewer system, which, as mentioned before, means that it will convey wastewater and stormwater together to be treated in the future treatment facility. This increases greatly the cost of water treatment since the volume of water that requires treatment is much bigger than if it was just from one source of discharge. Therefore, treating the stormwater runoff in situ by using sustainable stormwater control measures optimizes a combined sewer system and slows and reduces the volumes and peak flows of stormwater entering the sewer system. Volume reductions and peak flow desynchronization can help reduce the number of CSDs, reduce flooding, and improve water quality without the need of a treatment facility. As a result, these measures improve the capacity and efficiency of the city’s treatment facilities because they diminish the volume of water being treated. This has of course economic benefits.
Photo of combined sewer system discharge into the creek.
p a r t i c i p a t o r y s t o r m w a t e r m a n a g e m e n t f o r q u i t o e c u a d o r l a n d s c a p e a r c h i t e c t u r e & e n v i r o n m e n t a l p l a n n i n g p r o f e s s i o n a l p r o j e c t u n i v e r s i t y o f c a l i f o r n i a , b e r k e l e y 2 0 1 2
The EPMAPS is planning to expand their sewer system in this area by building an interceptor along the creek that will capture the water from the nearby neighborhoods, currently discharged directly to the creek, and convey it to a future treatment facility plant further downstream.
Proposed sustainable solution using vegetated swales to capture stormwater runoff.
Conventional combined sewer system as it exists in Quito.
14
The poorer people who come to cities from other places are not mad or mistaken. They flock to urban areas because cities offer advantages they could not find in their previous homes (Glaeser 2011). These newer communities still have linkages to a rural lifestyle and due to economic and cultural reasons it is still very common to witness the practice of several forms of agriculture in the interstices of this recently built urban matrix, specifically in empty or underused parcels. To implement a sustainable stormwater system, space is of great importance. One of the concerns with these types of systems is that they require considerable bigger areas to function than typical pipe systems. Thus, an analysis of the land ownership in the demonstration area is vital to be able to understand the feasibility and type of control measures of a sustainable stormwater system. Because of the absence of planning or regulation in this part of the city, there are not standard parcel or street sizes. Everything is unique and varies from block to block. The parcel sizes are also, in general, very small due to the subdivision among generations of land owners. The biggest and most important parcels, because of their downstream location, are located adjacent to the creek. Some of this land is already owned by the City, but a lot of it is private and built and occupied with families living right next to the creek, vulnerable to floodings and landslides.
15
Photo of occupied parcels by the creek.
As stated before, since the 1970’s Quito, like most cities in Latin America, experienced a rural population migration to the city. This rapid and spontaneous occupation of land around the city has caused a lot of problems to the city’s environment, in particular to the water cycle.
Photo of same location before the wall. Flood of 2009.
p a r t i c i p a t o r y s t o r m w a t e r m a n a g e m e n t f o r q u i t o e c u a d o r l a n d s c a p e a r c h i t e c t u r e & e n v i r o n m e n t a l p l a n n i n g p r o f e s s i o n a l p r o j e c t u n i v e r s i t y o f c a l i f o r n i a , b e r k e l e y 2 0 1 2
Land Ownership
Green parcels are public property. Yellow parcels are private not built. Brown parcels are private built.
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The PLCC-SAFEGE included a Mitigation Measures for Constructions at Risk study that is being implemented by the PSA of EPMAPS. These measures include several total or partial expropriations of parcels next to the Ortega Creek and other mitigation measures such as retaining walls. Again, this is a complicated problem of negotiating expropriations with families that have been living in these houses, some of them for more than 50 years. This relates to the issue of the lack of land use regulations in the past that incited “developers� to develop these lands for families moving in from the rural areas. Due to the fact that a lot of the parcels surrounding the creek are private, the City has now to invest and negotiate with the land owners to acquire this land in order to preserve the safety of the people that occupy this land and improve the environmental quality of the entire area.
cross section through parcel 5
landfill
Cross section from Eng. Elena Davila. EPMAPS Consulting work, 2009. (no scale) 16
p a r t i c i p a t o r y s t o r m w a t e r m a n a g e m e n t f o r q u i t o e c u a d o r l a n d s c a p e a r c h i t e c t u r e & e n v i r o n m e n t a l p l a n n i n g p r o f e s s i o n a l p r o j e c t u n i v e r s i t y o f c a l i f o r n i a , b e r k e l e y 2 0 1 2
cross section through parcel 9
cross section through parcel 13 (looking upstream)
Cross sections from Eng. Elena Davila. EPMAPS Consulting work, 2009. (no scale)
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p a r t i c i p a t o r y s t o r m w a t e r m a n a g e m e n t f o r q u i t o e c u a d o r l a n d s c a p e a r c h i t e c t u r e & e n v i r o n m e n t a l p l a n n i n g p r o f e s s i o n a l p r o j e c t u n i v e r s i t y o f c a l i f o r n i a , b e r k e l e y 2 0 1 2
Table resuming the SAFEGE study evaluation of the parcels ajacent to the creek.
ID
Owner
Parcel Area (m2)
Value/ m2
Total Value $
Construction Area (m2)
Construction year
1
Barrera J.
1435.00
18.07
93234.76
308
?
2
Camacho C.
575.50
19.87
11434.35
0
?
3
Sanguano A.
570.00
20.77
11838.90
459.43
1955
4
Sanguano M.
382.56
18.40
7039.10
144.96
?
5
Toapanta M.
342.26
18.40
6297.58
440.49
?
6
Vega J. V.
1415.00
18.40
26036.00
0
?
7
Mostrenco B.
2167.44
25.88
56093.35
0
?
8
?
603.72
?
0
?
Targeted in the study
9
Ramirez I.
696.02
20.88
164.68
?
The construction of a protection wall paid by the owner. If this agreement is not accepted the construction must be torn down.
10
?
425.93
?
0
?
Targeted in the study
11
?
539.80
?
0
?
Targeted in the study
12
Jimenez M. B.
6000.00
28.80
172800.00
0
?
13
Chamorro C.
950.00
42.48
61137.29
303.65
1955
14
Chamorro E.
328.80
43.20
43098.48
229.32
1994
15
Aucacama A. 868.80
43.09
41850.88
65.45
1955
16
Sarco P. E.
40.10
71766.16
141.48
1977
1500.00
14532.90
18
The Mitigation Measures for Constructions at Risk study (PLCC-SAFEGE) recommendations
The partial expropriation. If an agreement is not accepted the construction must be torn down.
Agree the tearing down of the constructions closer to the creek. If an agreement is not accepted the City must tear down the construction.
p a r t i c i p a t o r y s t o r m w a t e r m a n a g e m e n t f o r q u i t o e c u a d o r l a n d s c a p e a r c h i t e c t u r e & e n v i r o n m e n t a l p l a n n i n g p r o f e s s i o n a l p r o j e c t u n i v e r s i t y o f c a l i f o r n i a , b e r k e l e y 2 0 1 2
BACKGROUND
p a r t i c i p a t o r y s t o r m w a t e r m a n a g e m e n t f o r q u i t o e c u a d o r l a n d s c a p e a r c h i t e c t u r e & e n v i r o n m e n t a l p l a n n i n g p r o f e s s i o n a l p r o j e c t u n i v e r s i t y o f c a l i f o r n i a , b e r k e l e y 2 0 1 2
Integrated Urban Water Management (IUWM) The emergence and eventual widespread acceptance of the paradigm of IUWM has occurred globally during the last 25 years or so (Marsalek 2001). Several North American authors have attributed the origins of IUWM, in part, to the activities of the Urban Water Resources Research Council of the American Society of Civil Engineers, during the late 1960s and early 1970s (Grigg 1999). Certainly, the Council’s head, M. B. McPherson, was a strong advocate of applying the idea of a water balance to urban water resource issues, and introduced the need for a more holistic and integrated understanding about the way water supply, sanitation, and drainage systems operated (Mitchell 2006). IUWM has different definitions and interpretations depending on the institutions. According to the UNESCO book, Integrated Urban Water Management: Humid Tropics, IUWM is the practice of managing freshwater, wastewater, and stormwater as components of a basinwide management plan. This is a crucial scale for understanding the water issues and propose solutions. It builds on existing water supply and sanitation considerations within an urban settlement by incorporating urban water management within the scope of the entire river basin (Tucci, Goldenfum, and Parkinson 2009). This paradigm shift from how to approach water issues is the result of different international efforts on how to reenvision water resources management to serve the people, without damaging the environment. The “Dublin Statement” (International Conference on Water and the Environment 1992) formulated a number of principles that since have formed the basis for Integrated Water Resources Management (IWRM). IWRM addresses the issue of water management from a river basin perspective, since this is the scale that includes all relevant cause-effect relations and stakeholder interests. The “Agenda 21” (UN Department for Sustainable Development 1992) has worked out the “Dublin Statement” in some more detail for urban areas. The objective of “Agenda 21” is to develop “environmentally sound management of water resources for urban use”, IUWM (Tucci, Goldenfum, and Parkinson 2009).
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International Conference on Water and the Environment (1992)
Dublin Statement
Integrated Water Resources Management (IWRM)
Agenda 21
Integrated Urban Water Management (IUWM)
The traditional model adopted for the management of urban runoff is based on a misconception, as it involves draining runoff from urban surfaces as quickly as possible through a system of pipes and channels. However, this increases peak flow and the costs of stormwater management. Moreover, as there is no control measure, peak flow increases at minor drainage levels and impacts the central drainage system. To cope with this problem, many cities and public administrations have developed additional works, such as channels. But, this type of solution only transfers problems from one section of the basin to another downstream, with high consequential costs. In addition, water quality decreases, since runoff contains a larger amount of solids and a higher concentration of metals and other toxic components (Van der Steen 2006). There are two different approaches to deal with stormwater runoff, the traditional conveyance-oriented approach, designed to collect and rapidly convey stormwater to a discharge point; and, the storage-oriented approach, which function is to temporarily store the stormwater runoff at or near the point of origin and then slowly release it downstream (Walesh 1989) and infiltrate it to recharge the groundwater. The latter approach allows for a more sustainable system that can more closely restore the natural water cycle. The problem of increasing impervious surfaces and how it affects the runoff processes has been discussed for decades by many different authors such as Leopold (1968), McHarg (1969), Dunne (1970), or Hewlett (1970).
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Example of a conveyance system, channelized LA River. Source: Downtowngal, 2010.
PSM comes from IUWM as it envisions an integrated sustainable approach to deal with urban runoff. The reason why it is integrated is because it foresees the involvement of all stakeholders in planning, designing, building, and maintaining a system that promotes a environmental friendly way to detain, infiltrate and treat stormwater before it reaches the creek. It is also an opportunity to educate the community about the natural processes, urban watershed problems and how to solve them.
Example of a storage system, wetlands in Greenville, SC. Source: retentionponds.com.
p a r t i c i p a t o r y s t o r m w a t e r m a n a g e m e n t f o r q u i t o e c u a d o r l a n d s c a p e a r c h i t e c t u r e & e n v i r o n m e n t a l p l a n n i n g p r o f e s s i o n a l p r o j e c t u n i v e r s i t y o f c a l i f o r n i a , b e r k e l e y 2 0 1 2
Participatory Stormwater Management (PSM)
When designing these control measures for humid tropical or subtropical climates like the ones in most cities in developing countries, some parameters have to be carefully considered. The principal climatic-related impacts on water and wastewater facilities in the humid tropics are as follows: a) Rainfall intensity is about 25% higher than in temperate climates. This requires more investment for the same level of drainage control, since peak discharges of runoff are higher in proportion to higher rainfall intensity. b) Design conditions are based not only on local rainfall intensity, but also on rainfall duration. Low-intensity and long-duration storms maintain a high water level in the drains over long periods, creating a backing up of water from the large downstream (major) drainage system into the smaller, upstream (minor) drains, which contributes towards increased flooding. In this situation, the runoff exceeds the hydraulic capacity of the drainage system and streets are flooded. c) High temperatures in the tropics create conditions for water and waste treatment not found in temperate climates. These allow for the proliferation of microorganisms in waters (Tucci, Goldenfum, and Parkinson 2009).
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Example of a natural water treatment system in Havana, Cuba. Source: Baez, Y, Masters Thesis, 2008.
p a r t i c i p a t o r y s t o r m w a t e r m a n a g e m e n t f o r q u i t o e c u a d o r l a n d s c a p e a r c h i t e c t u r e & e n v i r o n m e n t a l p l a n n i n g p r o f e s s i o n a l p r o j e c t u n i v e r s i t y o f c a l i f o r n i a , b e r k e l e y 2 0 1 2
Stormwater Management in Humid Tropics
p a r t i c i p a t o r y s t o r m w a t e r m a n a g e m e n t f o r q u i t o e c u a d o r l a n d s c a p e a r c h i t e c t u r e & e n v i r o n m e n t a l p l a n n i n g p r o f e s s i o n a l p r o j e c t u n i v e r s i t y o f c a l i f o r n i a , b e r k e l e y 2 0 1 2
Stormwater Pollutants Stormwater runs off of surfaces, such as asphalt, concrete, and other types of pavement, rooftops, and even lawns, it carries different kinds of pollutants. These pollutants if not treated end up in creeks causing their degradation. This table summarizes the main categories of pollutants found in stormwater, their sources, and their environmental impacts.
Pollutant
Source
Environmental Impacts
Oxygen demanding materials
Vegetation, excreta and other organic matter.
Deplection of dissolved oxygen concentration, which kills aquatic flora and fauna and changes the composition of the species in the aquatic system. Odours and toxic gases form in anaerobic conditions.
Inorganic compounds of nitrogen and phosphorus.
Fertilizers, detergents, vegetation, animal and human urine, sewer overflow and leaks, septic tank discharges.
In high concentrations, ammonia and nitrate are toxic. Nitrification of ammonia micro-organisms consumes dissolved oxygen. Nutrient enrichment (eutrophication) causes excessive weed and algae growth blocks sunlight, which affects photosynthesis and causes oxygen depletion.
Oils, greases and gasoline.
Roads, parking areas, garages and gas stations (spillages and leakages of engine oil), and industry. Vegetable oils from food processing and preparation.
Pollution of drinking water supplies and impacts on recreational use of waters. Reduction of oxygen transfer at the water surface. Carcinogenic compounds may cause tumours and mutations in certain fish species.
Heavy metals, pesticides, herbicides and hydrocarbons.
Industrial and commercial areas. Leachate from landfill sites and improper disposal of household chemicals.
Toxic to aquatic organisms and accumulate in the food chain impairing drinking water sources and human health. Many of these toxins accumulate in the sediments of streams and lakes.
Suspended solids, sediments and dissolved solids.
Erosion from construction sites, exposed soils, street runoff and stream banks.
Sediment particles transport other pollutants that are attached to their surfaces. Sediments interfere with photosynthesis, respiration, growth and reproduction, and deposited sediments reduce the transfer of oxygen into underlying surfaces.
Higher water temperatures.
Increase in water temperature as runoff flows over impervious surfaces (asphalt, concrete, etc.).
Reduced capacity of water to store dissolved oxygen. Impact on aquatic species that are sensitive to temperature.
Trash and debris.
Domestic and commercial refuse, construction waste and various types of vegetation.
Blockages and constrictions to drainage channels, aesthetic loss and reduction in recreational value.
Source: Parkinson and Mark, 2005.
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The U.S. Environmental Protection Agency (EPA), the agency in charge of administering the Clean Water Act, gives this definition of stormwater management BMPs: A BMP is a technique, process, activity, or structure used to reduce the pollutant content of a stormwater discharge. BMPs include simple nonstructural methods, such as good housekeeping and preventive maintenance. BMPs may also include structural modifications, such as the installation of bioretention measures. BMPs are most effective when used in combination with each other, and customized to meet the specific needs (drainage, materials, activities, etc.) of a given operation. The focus of EPA’s general permits is on preventive BMPs, which limit the release of pollutants into stormwater discharges. BMPs can also function as treatment controls (EPA 2000). Many cities in the United States have been implementing these solutions broadly which are mandatory for any new development. For instance, in Portland, the Bureau of Environmental Services provides a Stormwater Management Manual (SWMM) that can be downloaded from their website. This is a technical document that outlines the City of Portland’s stormwater management requirements. The requirements defined in this manual apply to all development and redevelopment projects within the City of Portland on both private and public property (SWMM 2008). The City of Portland’s approach to stormwater management emphasizes the use of vegetated surface facilities to treat and infiltrate stormwater on the property where the stormwater runoff is created. Infiltrating stormwater onsite with vegetated surface facilities is a multi-objective strategy that provides a number of 24
Photo of vegetated swale along street in Portland. Source: Kadir, Khalid 2012.
Control measures, also called Best Management Practices, were terms initially used to refer to auxiliary pollution controls in the fields of industrial wastewater control and municipal sewage control. The term “Best Management Practice,” or BMP, originated in the Clean Water Act of 1972, and is now commonly used in the language of environmental management (UCSC Storm Water Management Program 2009).
Photo of curb detail for vegetated swale in Portland. Source: Kadir, Khalid 2012.
p a r t i c i p a t o r y s t o r m w a t e r m a n a g e m e n t f o r q u i t o e c u a d o r l a n d s c a p e a r c h i t e c t u r e & e n v i r o n m e n t a l p l a n n i n g p r o f e s s i o n a l p r o j e c t u n i v e r s i t y o f c a l i f o r n i a , b e r k e l e y 2 0 1 2
Control Measures
In February 2007, Port and SFPUC staff initiated a community planning effort to develop a regulatory guidance document that fulfills state and federal requirements for post-construction stormwater runoff control. The Guidelines represent the culmination of this effort. The Guidelines describe an engineering, planning, and regulatory framework for designing new infrastructure in a manner that reduces or eliminates pollutants commonly found in urban runoff. The Guidelines are designed to work within the context of existing San Francisco regulations and policies, and are consistent with the City’s and Port’s Building Code and Planning Code requirements (Beaupre et al. 2009). Portland and San Francisco, as many other cities in the United States and other developed countries, made the decision to have specific stormwater regulation and design guidelines accessible to their citizens.
25
Photo of detention basin in school in Portland. Source: Kadir, Khalid 2012.
In San Francisco the Public Utilities Commission (SFPUC) also released a manual that can be downloaded from their website, Stormwater Design Guidelines (Guidelines). Like many California municipal agencies, the SFPUC and the Port of San Francisco administer Stormwater Management Programs developed in accordance with the federal Clean Water Act and a State of California National Pollution Discharge Elimination System (NPDES) Permit. NPDES permits for stormwater specify a suite of activities that municipalities must undertake to reduce pollution in stormwater runoff. One of these is the development, implementation, and enforcement of a program to reduce pollutants in stormwater runoff from new development and redevelopment projects. This effort is commonly referred to as a post-construction stormwater control program (Beaupre et al. 2009).
Photo of vegetated swale in Portland. Source: City of Portland Website.
p a r t i c i p a t o r y s t o r m w a t e r m a n a g e m e n t f o r q u i t o e c u a d o r l a n d s c a p e a r c h i t e c t u r e & e n v i r o n m e n t a l p l a n n i n g p r o f e s s i o n a l p r o j e c t u n i v e r s i t y o f c a l i f o r n i a , b e r k e l e y 2 0 1 2
benefits, including but not limited to pollution reduction, volume and peak flow reduction, and groundwater recharge. These benefits play a critical role in protecting stormwater infrastructure and improving watershed health. The SWMM complements and supports the City’s Portland Watershed Management Plan, System Plan, Revegetation Program, Greenstreets Program, and other City standards and practices (SWMM 2008).
After selecting the type of treatment control measure that are appropriate for the site conditions and target the pollutants of concern, it’s necessary to size these control measures to achieve the required stormwater performance standards (Beaupre et al. 2009).
26
Photo of retrofitted street with vegetated swales in Seattle. Source: Kadir, Khalid 2012.
Existing site conditions, design and development goals, and the pollutants of concern for the site guide the selection of stormwater treatment control measures. On-site percolation tests and geotechnical investigations must be done during the site analysis to determine whether infiltration-based control measures are feasible for the site. However, infiltration based control measures need not always be eliminated based upon this information. Rather, a modified design solution can make a control measure feasible. Vegetated swales can be used for stormwater treatment in areas with poor infiltration or contaminated soils provided that they are lined with an impermeable liner, underdrained, and constructed with clean import soil. Steep slopes can limit the range of appropriate control measures for a given site because they can cause high flow rates and instability. Terracing the site is one design solution that could allow the implementation of slope-dependent control measures on a steep site. Check dams can also be used to mitigate problems caused by steep slopes.
Photo of detention basin in Portland. Source: Kadir, Khalid 2012.
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Stormwater management control measures are planned, designed, and built to mitigate changes to both quantity and quality of urban runoff caused through changes to land use. Generally control measures focus on water quality problems caused by increased impervious surfaces from land development. Control measures are designed to reduce stormwater volume, peak flows, and/or nonpoint source pollution through evapotranspiration, infiltration, detention, and filtration or biological and chemical actions.
Treatment control measures whose primary mode of action depends on volume capacity to remove pollutants, such as retention or infiltration structures, should be designed to treat a volume of stormwater runoff equal to: - The maximized stormwater quality capture volume for the area, based on historical rainfall records, determined using the formula and volume capture coefficients; or - e.g. in California, 80 percent of the volume of annual runoff, determined by using local rainfall data. In California, treatment control measures whose primary mode of action depends on flow capacity, such as swales, sand filters, or wetlands, should be sized to treat:
Photo of constructed wetland in Portland. Source: Kadir, Khalid 2012.
There are two sizing standards for building treatment controls, volume-based sizing and flow-based sizing.
- 10% of the 50-year design flow rate; or - The flow of runoff produced by a rain event equal to at least two times the 85th percentile hourly rainfall intensity for the applicable area, based on historical records of hourly rainfall depths; or - The flow of runoff resulting from a rain event equal to at least 5 mm per hour intensity (BASMAA 2003). The formula used to size the control measure is V = CAd where, V = volume of water, A = size of the drainage area that drains to the proposed control measure, C = composite runoff coefficient, and d = design rainfall depth.
27
Photo of vegetated swale in Berkeley. Source: City of Berkeley Website.
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Sizing Control Measures
p a r t i c i p a t o r y s t o r m w a t e r m a n a g e m e n t f o r q u i t o e c u a d o r l a n d s c a p e a r c h i t e c t u r e & e n v i r o n m e n t a l p l a n n i n g p r o f e s s i o n a l p r o j e c t u n i v e r s i t y o f c a l i f o r n i a , b e r k e l e y 2 0 1 2
Composite Runoff Coefficient (C) This variable corresponds to the relation between rainfall and runoff. It is the most difficult variable to estimate because it relies on intuitive interpretation. It is the result of many factors such as soil type, slope, and ground cover. In fact, the variable can change depending on seasonal conditions, i.e., soil moisture and capacity for infiltration. Therefore, it is common to use average values to simplify the calculations. In most cases, a drainage area is composed of subareas with different runoff coefficients, thus a composite coefficient for the total drainage area is calculated by dividing the sum of the products of the subareas and their coefficients by the total area (Development Services Center (DSC) 2008):
URBAN AREAS Street: Asphalt
0.70-0.95
Concrete
0.80-0.95
Brick
0.70-0.85
Drives and walks
0.75-0.85
Roofs
0.75-0.95
Lawns: Sandy soil, gradient ≤ 2%
0.05-0.10
Sandy soil, gradient ≥ 7%
0.15-0.20
Heavy soil, gradient ≤ 2%
0.13-0.17
Heavy soil, gradient ≥ 7%
0.25-0.35
The values above can be used, together with areas of each type of surface measured from a map or aerial photograph, to compute weighted average values of C. RURAL AREAS Sandy and gravelly soils: Cultivated
0.20
Pasture
0.15
Woodland
0.10
Loams and similar soils without impeding horizons: Cultivated
0.40
Pasture
0.15
Woodland
0.30
Heavy clay soils or those with a shallow impeding horizon; shallow soils over bedrock: Cultivated
0.45
Woodland
0.40
Source: Dunne and Leopold. Water in Environmental Planning, 1978.
Composite C = ∑(Cindividual areas)(Aindividual areas)/Atotal area
The table is the result of a compilation of values from the American Society of Civil Engineers 1969, Rantz 1971, and others. 28
0.50
Pasture
The idea of public participation in urban planning, first initiated in the 1960s, became really popular in mid-1970s after the sites and services housing schemes received funding and acceptance by the World Bank in the developing countries (Hamdi and Goethert 1997). However, the use of public participation has been done in a careless manner in many projects claiming to have public participation as a component of the process leading to an ineffective real community involvement. First, the term community has both “social and spatial dimensions” and generally the people within a community come together to achieve a common objective, even if they have certain differences. Communities are not necessarily always organized and cohesive. For community participatory projects, it is not an imperative to have an already well-organized community right from the beginning because the sense of community can be achieved during the course of the project, which can also be one of the objectives of including community participation in development projects. Public participation is a powerful idea that “refers to the process by which professionals, families, community groups, government officials, and others get together to work something out, preferably in a formal or informal partnership”. Public participation was initially an outcome of the public pressure demanding “environmental justice” (Hamdi and Goethert 1997). Christopher Alexander explains that “participation is inherently good; it brings people together, involves them in their world; it creates feelings between people and the world around them, because it is a world they have helped to make.” People enjoy changing their environment, having a sense of ownership and identifying with it. (Center for Environmental Structure 1975). 29
Community working in landscaping, Vermont, USA. Source: central-vt.com
Community involvement is widely understood as critical to achieving the level of support necessary for successful implementation of new policies, plans and projects (Iacofano and Lewis 2011). There are several definitions of community involvement, also called public participation, presented by various theorists, as well as different stages and levels of public participation in the entire, planning through construction and maintenance, process.
Community meeting in Quitumbe, Quito, 2009.
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The Importance of Community Involvement
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There are different stages in the overall process where public participation can be accomplished: initiation, planning, design, implementation and maintenance. Initiation is the first stage of the process where the project goals and scope are defined. The planning stage involves working out the project details, budgeting and resource identification. In the design stage, the details are further developed, with the actual execution of the project in the implementation or construction phase. The maintenance or management stage is a long-term process and involves the upkeep of the project (Hamdi and Goethert 1997). The involvement of the community at different stages of the process will determine the level of participation. Sherry R. Arnstein, in the article “A Ladder of Citizen Participation,” published in 1969 in the Journal of the Planning Association, classifies public participation in eight different types arranged in a ladder pattern with each step corresponding to the extent of citizens’ influence in the final outcome of a project or plan. From bottom-up the steps are: manipulation, therapy, informing, consultation, placation, partnership, delegated power and citizen control. The steps at the bottom of the ladder are the ones with least citizen participation or “nonparticipation” and include Manipulation and Therapy. Informing, consultation and placation occupy the middle steps of the ladder and border between manipulation at the bottom and citizen control at the top and is termed as “tokenism” where the people are allowed to participate only to the extent of expressing their views but have no real say that influences the outcome. The last three steps, partnership, delegated power and finally citizen control at the top of the ladder, are termed equivalent to “citizen power” and this is where true and meaningful participation takes place. This categorization of the various types of people involvement is extremely crucial in clarifying the confusion between “non-participation” and true “citizen power” and to identify the real motives behind participatory projects (Arnstein 1969).
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8. Citizen control
7. Delegated power
Citizen power
6. Partnership
5. Placation
4. Consultation
Tokenism
3. Informing
2. Therapy Nonparticipation 1. Manipulation
Eight Steps on the Ladder of Citizen Participation, Source: Sherry R. Arnstein, 1969.
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Public participation can roughly be distinguished in two approaches, the top-down or bottom-up (Moser 1989). By the end of the 1960s, bottom-up community participation initiatives started to surface along with top-down participation programs in the form of squatter settlements around the world. These bottom-up initiatives of the community in order to house themselves resulted after the failures of top-down housing projects in different cities of the world. However, by the 1970s, many governments of developing countries and donor agencies realized the potential of these community-based initiatives which resulted in a major change of approach in housing in the form of upgrading and sites and services projects (Moser 1989). Another author, G. Narayana Reddy, in his book Empowering Communities through Participatory Methods, says that in the topdown model of participation, the governments decide and supply for the communities which develops a sense of dependence and idleness among the people. His solution to the top-down model is a “partnership model� where the government and communities work together in planning and decision-making with longer-lasting results as shown in the figures next.
Top-down model: giving everything for free
doing everything for them
community
dependency
lethargy
Public participation can be used to achieve local urban improvements such as housing projects, sanitation programs, etc. but it can also lead to actual social benefits to the community. Partnership model: Participating in all steps of the project development, from planning, designing, building and maintaining it, gives the community a feel of ownership and autonomy. planning and decision control over their making together affairs working and benefiting together permanent partnership
community
dignity to the poor sustainability of project Top-down vs Partnership models by G. Narayana Reddy, 2002
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Community Involvement in Quito In recent years Ecuador has evolved towards democracy and decentralization of power. Until the 1980’s, military governments ruled the country. The first democratic elections were held in 1979 and since then democracy it has been consecrated in the country’s Constitution that it has a unique, decentralized, and participative government. One of the fundamental characteristics of community involvement in Ecuador is that it did not emerged from a grass roots movement. It was not an earned right of the masses. Quite the contrary, it was superimposed by an elite coalition (left wing Christians, Environmentalists and Humanists) that arrived to power under special circumstances. In the first decade of the 21st century, the traditional political parties had become so corrupt that the entire political system was brought to a collapse. The void created by the party system gave rise to the coalition mentioned above. They wrote a new constitution that is very advanced and idealistic. It included among other things the creation of a fourth power: citizen participation in the main decisions of government. But since Ecuador has not had a tradition of public participation, some of the same idealistic new politicians, who are now in power at the national level, have gone back to the old ways of populism and manipulate this fourth power for their own interests (email conversation with anonymous planning practitioner in Ecuador). Following the principle of the Constitution, the City of Quito has, according to its regulatory framework, the responsibility of providing the integration and community participation in identifying their needs and in the planning of projects destined to answer those needs (Articulo 2 – Ley Orgánica de Régimen para el Distrito Metropolitano de Quito). The promotion of public participation is orchestrated by a set of institutions that are structured in a broad and complex way: the Quito Assembly, different scales of cabildos,1 parish meetings, etc. However, despite the effort from the City to develop a successful participatory process, by even creating a Participative Management System which aims to articulate and define opportunities for participation, there are still several issues: 1
. A neighborhood system of assemblies with elected representatives. 32
• The procedures and municipal structures have not been modernized enough, so there are still bureaucratic practices that block community involvement; • Although it has been more efficient in providing services, the municipal management model, which forms corporations, foundations and local companies, has weakened the ability of authorities to implement public participation as a policy; • The Participative Management System is in its initial stage of implementation and does not yet have a final regulatory framework; • The lack of coordination between different participatory agencies causing duplication and lack of awareness of current initiatives; •
And other problems such as:
o Difficulties by municipal employees in managing the time dedicated to public participation with other personal responsibilities; o
Low educational levels of the population;
o Misconception of public participation processes as decision-makers seek to present immediate results, and long-term processes are aborted. o Politicization by groups who see the participatory process as a political platform for personal ambitions (García 2010).
But still, the community involvement is not perfect in terms of autonomy, mostly because it seems that there is a lack of an educational and communication components to explain the natural processes, the causes of the existing problems, and the alternative solutions in a way that is accessible and interesting for the community members. These are also new solutions for the technitians and engineers in the field talking to the communities. Therefore this message has to reach not only the community but all the stakeholders.
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Â
Community meeting in Quitumbe Quito, 2009.
Other local community organizations emerged in recent years as well and are doing valubale work with the poorest communities. For instance, as mentioned above, the Ortega Creek was restored recently by the community organization – AMCQ Solidaridad – that employs and educates local impoverished citizens. It not only coordinated the intervention in the creek to improve its quality and recreational use but it also has its hand in community housing, financial aid, etc.
Community meeting in Quitumbe, Quito, 2009.
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However, in the recent studies requested by the EPMAPS, public participation has been an important component of the work. In 2009 the PLCC team organized several meetings with the local communities to access the risk awareness of occupying steep slopes and floodplains, and to show the projects that were being studied to prevent potential disasters. Until today the teams of the EPMAPS in charge of managing this process are still in the field making periodic visits to communities and barrios. The municipality, through its Zonal Administrations, also has community involvement task teams that know the people, the problems, and the community leaders.
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Orangi Pilot Project Precedent There are a vast range of examples, methods and approaches of community involvement in developing countries. Some examples are: the Community Action Planning (Microplanning) approach, developed by the Nabeel Hamdi and Reinhard Goethert in Sri Lanka as part of the Million Houses Program and now used worldwide, in Bangladesh, South Africa, USA, and Poland; the ZOPP (Goal Oriented Project Planning) is used and promoted by the Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ). The ZOPP has been criticized for its rigidity and sometimes failed due to the disinterest of local partners; and the Urban Community Assistance Team (UCAT) approach where a selected interdisciplinary team of professionals together with local supporters prepares recommendations and development schemes. The UCAT originates from the R/UDAT – Regional/Urban Design Assistance Team – events pioneered by the American Institute of Architects since 1967, hence its design orientation and its prevalent use by architects and physical planners (Hamdi and Goethert 1997). However, due to its simplicity and effectiveness, the Orangi Pilot Project (OPP) is exemplary. It was started by Dr. Akhtar Hameed Khan as a sanitation program for a low-income area in the City of Karachi, Pakistan. Dr. Khan’s preliminary investigation concluded that the residents were quite aware of the twin problems of sanitation and drainage. They clearly saw the causes of damage to their health and property. Then why did they not exert themselves to construct their sanitation and drainage as they had exerted themselves to build their streets and houses?
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Dr. Khan’s research discovered four barriers: 1. The psychological barrier: Orangi residents firmly believed that it was the duty of the official agencies to build sewerage lines as free of charge. Their leaders encouraged and confirmed the belief in free gifts. 2. The economic barrier: the conventional cost for sanitary latrines and underground sewerage lines built by official or commercial agencies was beyond the paying capacity of low-income families. 3. The technical barrier: the low-income families had indeed built their houses, mostly with the advice of masons, and they had also built bucket latrines and soakpits. But neither the people nor their advisors, the masons, possessed the technical skill required for construction of underground sewerage lines. 4. The sociological barrier: construction of underground sewerage lines requires not high technical skill but also social organization for collective action. This did not exist in Orangi streets in 1980 (Khan 2005).
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Thus, Dr. Khan’s started the OPP, which did not carry out development work, but promoted community organizations and co-operative action, and provided technical support to such initiatives. In a nutshell the OPP functioned like this: “Dr. Khan came across a number of Orangi activists who had an element of radicalism in them. Some of them had been members of political movements against exploitation and injustice. Some of them had also been involved in settling Orangi with the help of the informal developers. They were at ease in Orangi, “like fish in water”, they were “uncut diamonds” and the people also knew them well. Dr. Khan recruited four of these activists as social organizers of the OPP. The first step for providing such a support was the creation of a technical unit within the OPP. This was established. An Orangi-based engineer was recruited along with a local plumber, a draftsman and a technician. Survey and leveling instruments were provided to the team. The next step towards building a sewerage system was the creation of community organizations. The street, which in Orangi consists of about 20 to 30 houses, was made the unit of organization. First the OPP social organizers, who were Orangi residents and activists, would hold meetings in the street and with help of slides, models and pamphlets, explain the program to the people, along with its economic and health benefits. The motivators would tell the people that if they formed an organization in which the whole street participated, elected, selected or nominated street managers, and applied to the OPP for assistance, then the OPP would help them. In the second stage, the organization was born and chose its street managers who, on behalf of the street, formally asked for assistance. In the third stage, the OPP technical staff surveyed the street, established benchmarks, prepared plans and estimates (of both labor and materials), and handed over this data to the street managers… Lastly, the street managers collected the money from the people and called meetings to sort out any sociological or technical problems involved in the work. The OPP staff supervised the process. At no time, however, did the OPP handle the money of the people”. (Hasan 2010) 35
Photo of street in Orangi before the installation of the sewer system. Source: Akhtar H. Khan, 2005.
So what lessons can be taken and applied to Quito? Identify community organizations and prominent individuals in the community (the activists) and listen to them to set community goals. EPMAPS and the QZA have already completed this task and transmitted their needs and demands. Community-wide goal setting is essential to determine needs and priorities (Hester 1985). For instance, a known request from the community around the study site is the restoration of the public pool that has been closed for a long time. The QZA believes that incorporating this project within the general scope of the proposal will trigger a support effect from the entire community. Another lesson from the OPP is the importance of providing the people the know-how and tools to implement their own system. This is most likely the greatest achievement of this project and the biggest lesson to take under account for a successful community involvement process.
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Community meeting in Orangi. Source: Akhtar H. Khan, 2005.
This project was so successful that the World Bank and the UN have copied it in other developing nations around the world.
Community in Orangi installing their sewer system. Source: Akhtar H. Khan, 2005.
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Everyone quickly realized that the cost of building this sewerage system was reduced to a surprising extent by a) simplifying designs and methods of construction, and b) eliminating kickbacks and profiteering by providing free technical guidance to street managers and enabling them to work without contractors. (Khan 2005)
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OBJECTIVES
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The objective of this proposal is to design an alternative, more sustainable drainage solution to tackle the problems of water quality and natural disasters that afflict the City of Quito using a specific site, in the Ortega Watershed, in one of the most impoverished areas of the city as a demonstration area. This area still has daylighted streams and available space, which are valuable conditions and provide an opportunity to implement this sustainable solution. Natural disasters, such as floodings and landslides, are directly related to increases of impervious areas and channelization, in which human-made conduits and drainage channels are designed to drain runoff as quickly as possible. These floods are not natural events and are created as a result of urban development (Tucci, Goldenfum, and Parkinson 2009). Since the 1970s in developed countries, the concept of stormwater management has evolved through the application of new technologies, such as detention and retention ponds, permeable surfaces, infiltration trenches and other source control measures. This approach has been implemented through municipal regulations in developed countries and the land developer pays the cost of implementation and control (Tucci 2007).
Before urbanization the infiltration was high, the groundwater recharge was high and the surface runoff was minimum.
However, in developing countries, this type of control usually does not exist and the impacts are transferred downstream into the major drainage system. The cost of the control of this impact is transferred from the household to the public domain, since the municipality has to invest in hydraulic structures to reduce the downstream flood impacts (Tucci, Goldenfum, and Parkinson 2009). Where urban runoff occurs, a disturbance has taken place; mitigation and restoration are necessary. In the midst of a city, restoration of ecological processes depends on human protection and management. The characteristics of a place can make the processes through which hydrologic and ecological restoration takes place visible and comprehensible. Design is capable of revealing and integrating (Ferguson 1998).
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Now the infiltration is less, the groundwater recharge is minimum and the surface runoff is high.
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Urban infiltration constitutes the restoration of a site’s hydrologic process. It restores groundwater to the earth and balanced flow regimes to streams. In addition to addressing flooding and erosion, which are targeted by conveyance and detention systems, infiltration supports groundwater recharge, stream base flows, water quality, aquatic life, and water supplies. Because it turns the hazard of storm flows into the resource of base flows, it is environmentally the most complete solution to the problem of urban stormwater (Ferguson 1998). Although it is known that these control measures increase the storage and infiltration capabilities in the watershed, reducing flooding and erosion, and improving the general environment and thus the quality of urban life, the challenge is how to implement them in a low-income and poorly educated community. These systems require careful maintenance and the ideal situation would be that the community would take charge of that. Thus, involving the community in the identification of the problems, explaining to the community the ecological processes functioning in the neighborhood, and presenting some alternative solutions with different uses that they can build and maintain themselves is ideal. An effective community involvement process is essential for the successful implementation of the project. Learning from other case studies making people responsible for their actions as well as for their solutions is essential. Therefore the purpose of this project is not only to propose an alternative, a more sustainable solution for stormwater runoff, but how to pass that message to the community. From all the problems caused by runoff, especially in this area, water quality is the one that people most complain about. So the design has to focus particularly in this problem of how to use landscape based control measures that can slow, divert, and treat the water before going into the Ortega Creek. Increasing storage and infiltration capabilities in the streets is one way to achieve a more sustainable stormwater system. 39
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METHODS
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This chapter will explain the methods used for this project. Planning and designing a stormwater system comprises several steps and different technicalities, like determining the steepest slope where a detention/ retention site can be excavated; or determining if a sedimentation basin will be required; and selecting the plant material accordingly to the flooding periods. Also, other non-technical issues need to be addressed, such as determining the community recreation needs along with developing a multipurpose storage system; and assessing safety hazards and find out how to control them (Walesh 1989). Although a common practice in the United States, this kind of stormwater management is not well known in cities in developing countries. Thus, the methods used in cities like San Francisco or Portland are references for this design. The community involvement was inspired by precedents such as the OPP, using a communication outreach to educate not only the community but also the EPMAPS’ engineers and technicians. The methods include: site visits and field observation; satellite imagery analysis and manipulation to determine land cover; percolation tests; existing runoff flow mapping; delineation of drainage areas; water quality analysis; rainfall record data analysis; hydrologic calculations; mapping of different parameters such as land ownership and existing and projected sewer systems; selection of control measures; overall functioning of the system; and communication of ideas. The design proposal should be verified again on site as the team becomes more familiar with the problems and needs in the watershed and within the larger community. There may be an opportunity to solve some other problems and satisfy some of these needs while advancing the implementation of the stormwater system (Walesh 1989).
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The selection of the demonstration area was done during the site visits with the staff of the EPMAPS and confirmed with the staff of the QZA. It was also useful to see the work of the community organization, ACMQ Solidaridad, and contact some of the people behind it. The community organization showed interest from day one in following up with this project. During the trips to Quito several meetings were held to present some ideas of sustainable stormwater alternatives as well as the idea of involving the community in the planning, designing, building and maintaining the proposed stormwater system. It was also interesting to observe the characteristic climate conditions, in particular the precipitation. Short and intense rainfalls, especially in the south side of Quito are constant and something that the team needed to take under consideration when designing the system.
Photo of digging for percolation test.
Together with data collection, site visits and field observation are fundamental to understand the problems and evaluate opportunities. Talking to the people involved was essential, not only the engineers from the EPMAPS, but also with the sociologists and staff in the field that contact directly with community members.
The percolation test was done during the second trip to Quito in January. The percolation consisted in digging two holes in different locations along the creek to determine roughly the infiltration rate of the soils surrounding the creek. This information is vital to choose the appropriate control measures. The percolation test was a normal landscape test typically used by landscapers to determine the type of soil in order to chose the right plant material. The holes were 1 cubic feet each, filled with water from the site, and then covered. Twenty-four hours later the team visited the site again to uncover the holes and find the same amount of water in them. It was not exactly a surprise because the soils are mostly clay and saturated due to the constant rain. This information indicates that water infiltration for this site is difficult without some soil mixture. Introducing a layer of gravel on the bottom of the control measures is one solution. 42
Photo of hole filled with water.
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Site Visits and Field Observation
The process involved in determining the current flow patterns requires the following information: topography, in this specific case the topography used was 1 m contour map; the parcels outine to map the street grid; and, the combined sewer system along the streets. All this original data was provided by the Geoprocessing Department from the EPMAPS. By overlaying these three differents data sets it is possible to have an accurate idea of the flow patterns along the streets and where in the creek they discharge. Of course, like all cartographic information error has to be accounted for. The accuracy of the survey or of the data input into digital is a typical problem that designers and planners have to deal with. Positional errors are inevitable when data are manually digitized. These error may be “small� relative to the intended use of the data, for example less than 2 m when only 5 m accuracy is required. However these relatively small errors may still cause problems when utilizing the data (Bolstad 2005).
Topography - 1 m contours.
The first step in designing a stormwater system is to evaluate the existing runoff conditions of the site. It is important to understand where the current runoff flows to in order to antecipate specific locations to install the control measures. Ideally the control measure will capture the confluence of the runoff and carry it downstream.
Therefore, it is important, in a future developing stage of the project, to confirm these existing flow patterns in the field. Following the runoff during a rainfall event or talking to the local people, to figure out where in the neighborhood it usually floods, are two methods that fill the gap of the remote sensing analysis and need to be done before the final hidrologic calculations.
Street grid.
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Existing Flow Conditions
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Drainage Areas
A
B
C
D
E
F
G
Size in m2
62 708
69 492
22 443
49 965
47 990
20 139
32 621
H 9 754
This is the first piece of information for sizing the control measures. This demonstration project does not aim to restore the water quality of the creek. It aims to demonstrate the alternative stormwater system solutions that can be implemented to balance the natural hydrologic conditions of the site and improve the water quality of the stormwater runoff. To treat the water from the entire creek this type of solution should be implemented at the watershed scale and to all watersheds upstream.
Existing stormwater flow.
From this information it is possible to delineate and quantify eight different drainage areas within this study area that drain directly from the site to this stretch of the creek.
Drainage areas.
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As shown in the image the existing runoff flow patterns follow the street grid and discharge into the creek in specific locations. This runoff from the streets washes the pollutants into the creeks, decreasing the water quality. The water quality is not just affected from the stormwater runoff and sewage discharge from this site but also from other peri-urban areas upstream.
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Neither the City of Quito nor the EPMAPS have recent aerial imagery of the north or south edges of the city. To perform this analysis the team had to acquire satellite imagery from June 2011 from a remote sensing and surveying company, Satellite Imaging Corporation, based in Texas. The image coordinates are 0˚20\’07\’\’S, 78˚35\’05\’\’W, 0˚17\’30\’\’S, 78˚32\’57\’\’W, corresponding to the southwestern quadrant of the City of Quito (side image). The imagery files included in the package are the orthorectified 16 bit Multi-Spectral Multi-Layer GeoTIFF with a 2 m resolution and a 16 bit Panchromatic image with a 50 cm resolution. This information is important because these are the minimum requirements for this analysis. The multi-spectral means that the image supported a 4-band (infrared) which is used for ground cover analysis. The infrared feature is particularly relevant because it will show the different levels of radiance and distinguish between soft and hard surfaces. The steps to manipulate the imagery are the following:
Original acquired satellite image.
This procedure will demonstrate how to run a land surface analysis in order to classify and quantify runoff coefficients based on the table from the American Society of Civil Engineers 1969, Rantz 1971, and others (pag. 28).
Load the MS image to ArcMap 10. When loaded, images often show up on screen fully black. To fix this, go to layer properties and change stretch in symbology to “Standard Deviations”. This will make the image clear. Then, still in properties, change the Red, Green and Blue channels to bands 4, 3 and 2, respectively, and the infrared image will show up. The infrared image has a 2 m resolution, which is not the best definition, so the panchromatic sharpening is useful. Panchromatic sharpening uses a higher-resolution panchromatic image (or raster band) to fuse with a lower-resolution multiband raster dataset. 45
Close up of demonstration area.
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Satellite Imagery and Manipulation
The IHS transformation was the one used in this case. It converts the color image from an RGB color model to an IHS color model. It replaces the intensity values with those obtained from the panchromatic image being used to sharpen the image, a weighting value, and the value from an optional, near-infrared band. The resultant image is output using the RGB color mode.” (ESRI) Because, the fourth band of the raster dataset is the infrared band, it’s necessary to check the “4th band as Infrared Image”. The next step is to classify the image according to the different ground covers. There are three distinct ground covers observed in the image and from the visits to the site, naked ground, rooftops, and asphalt. Rooftops and asphalt have, according to the table on pag. 28, very similar runoff coefficients, so it was assumed to classify it as one. Thus, the image was classified in hard-surfaces and softsurfaces.
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Infrared image.
“Panchromatic sharpening is a radiometric transformation available through the user interface. Several image companies provide lowresolution, multiband images and higher-resolution, panchromatic images of the same scenes. Panchromatic sharpening is used to increase the spatial resolution and provide a better visualization of a multiband image using the high-resolution, single-band image. ArcGIS provides four image fusion methods from which to choose to create the pan-sharpened image: the Brovey transformation, the IHS transformation, the ESRI pan-sharpening transformation, and the Simple Mean transformation. Each of these methods uses different models to improve the spatial resolution while maintaining the color, and each is adjusted to include a weighting so that a fourth band can be included (such as the near-infrared band available in many multispectral image sources). By adding the weighting and enabling the infrared component, the visual quality in the output colors is improved.
Infrared image with panchromatic sharpening.
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The result produces a multiband raster dataset with the resolution of the panchromatic raster where the two rasters fully overlap.
Add the Image Classification toolbar. The Image Classification toolbar provides a user-friendly environment for creating training samples and signature files. A signature file records the spectral signatures of different classes across a series of bands) for supervised classification. (Blog ESRI) Then collect training samples of the areas of interest. In this case, a few samples from the rooftops and asphalt and a few samples from naked ground. Once done collecting training samples save the signature file. Then, to actually classify the image, use the Maximum Likelihood method for supervised classification. Based on the maximum likelihood probability theory, this method assigns each pixel to one of the different classes based on the means and variances of the class signatures (stored in the signature file you saved earlier). (Blog ESRI)
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Brown represents hard-surfaces (impervious). Green represents soft-surfaces (pervious).
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“The image classification process involves conversion of multiband raster imagery into a single-band raster with a number of categorical classes that relate to different types of land cover. There are two primary ways to classify a multi-band raster image; supervised and unsupervised classification. Using the supervised classification method, an image is classified using spectral signatures (i.e., reflectance values) obtained from training samples (polygons that represent distinct sample areas of the different land cover types to be classified). These samples are collected by you, the image analyst, to classify the image. With the unsupervised classification method, the software finds the spectral classes (or clusters) in the multi-band image without the analyst’s intervention, thus being unsupervised. Once the clusters are found, you then need to identify what the cluster represents (e.g., water, bare earth, dry soil, etc…).” (Blog ESRI)
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With the image classified according to soft vs. hard surfaces, it is necessary to load the shapefiles of the individual drainage areas. Clip the classified raster image with each of the drainage areas. This will create a raster data set for each individual drainage area. Finally, for each drainage area the only procedure is to open the properties of the corresponding raster data set and see the pixel count (each pixel corresponds to a 4 m2 area) for the soft and the hard surface areas. The values for asphalt vary between 0.70 and 0.95 and the values for rooftops vary between 0.75 and 0.95. Thus the value of 0.85 was assumed as the runoff coefficient for all hard surfaces of the site. The soil type, from field observation, consists of a lot of clay so although the terrain isn’t particularly steep the runoff coefficient chosen for the naked ground areas was 0.30. Assuming a 0.85 runoff coefficient for hard surfaces and a 0.30 runoff coefficient for soft surfaces. The composite runoff coefficients for each drainage area are:
Drainage Areas
A
B
C
D
E
F
G
H
Soft (m2)
8 304
9 136
4 472
7 724
9 344
2 712
5 304
3 348
Hard (m2)
54 760
60 372
18 000
42 268
38 672
17 332
27 204
6 444
Added Total A.
63 064
69 508
22 472
49 992
48 016
20 044
32 508
9 792
Real Total A.
62 708
69 492
22 443
49 965
47 990
20 139
32 621
9 754
Error
356
16
29
27
26
-95
-113
38
C
0.78
0.78
0.74
0.77
0.74
0.78
0.76
0.66
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For a matter of representation the team decided to assume a 1 m deep detention basins for treating the runoff volume of water from each drainage area. Therefore, each drainage area needs a different area for control measures. The image shows the resulting area requirements (red squares) for each of the eight drainage areas. The values range from 100 m2, for the smallest drainage area, and 600 m2 for the biggest ones. The follwoing step is to study where to allocate these areas in the site. To do this the team looked into parcel ownership to try to figure out what parcels could be available to locate the control measures, more specifically the detention basins. As it can be seen in the image, there is a lot of available public space along the creek, ideal to locate some detention basins.
Red squares represent the requirements in terms of area for 1 m deep control measures.
From the rainfall records that the team had access to from the EPMAPS and from the internet, the maximum rainfall registered in a day in Quito is average 10 mm. The team decided to design the control measures based on this number. The precipitation in Quito is, as mentioned before, characterized by intense 15 minutes rainfall events. Thus, the 10 mm, also correspond to that flush of runoff that drags the pollutants from the hard surfaces and needs to be captured. The objective is to catch the runoff from the streets and convey it, slowly, to detention basins, where the water is filtered and cleaned before being discharged into the creek.
PUBLIC: BUILT NOT BUILT PRIVATE: BUILT NOT BUILT
Parcel ownership map.
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With the information from drainage areas and corresponding runoff coefficients it is possible to conceive the control measures to a desired rainfall depth.
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Location of the 11 cross sections.
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Finally in terms of spatial analysis the last thing that was verified was the slope along the streets and into the available areas along the creek. This was done by tracing 11 cross sections throughout the study site to illustrate slope. Verifying the slope is important to determine if there are any stretches with steeper slopes, higher than 7%, to which the control measures would have to adjust. Check dams along the swales is one solution to deal with steeper slopes. This is a design solution that needs to be confirmed on site.
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PRELIMINARY DESIGN
Vegetated Swales Swales are open channels with unobstructed flow. They are vital parts of almost any drainage system and any landscape. Drainage in contact with soil increases vegetative variety, reduces velocity, decreases downstream peak flow, permits infiltration, symbolizes interaction with nature, and supports wildlife habitat and potential human amenity (Thayer and Westbrook 1990). As water flows through vegetated swales, its quality is affected to some degree. Unlike smooth, impervious gutters, pipes, and channels, vegetated swales store runoff while conveying it at low velocity and provide a large surface area in contact with vegetation and soil for biophysical treatment and infiltration (Ferguson 1998). The special criterion for runoff biofiltration is limiting velocity to 0.5 fps (0.15 m/s). Swales with this velocity capture 63 to 83 percent of particulate pollutants and those other pollutants that adhere to vegetation, including sediment, metals adsorbed on sediment, and oils. Swales are less effective for dissolved metals and nutrients (29 to 46 percent removal), and their effectiveness for bacteria is variable. Where a biofilter swale is added specifically for pollution control, it should be at least 200 feet (60 m) long so that residence time in the swale is at least nine minutes (Ferguson 1998).
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Proposed location of the vegetated swales.
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This chapter explains the preliminary design idea based on the previous analysis. It is relevant to emphasize the preliminary stage of this project. Several parameters need to be verified in the field in order to come up with a more detailed design. This is a suggestion of the types of control measures and how they can be implemented that needs to be discussed with the client, the EPMAPS, and also with the local community.
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The vegetated swales will capture the stormwater runoff and convey it downstream to detention basins. This will prevent the water from entering the combined sewer system and therefore the need to treat it in the future treatment facility plant. The image bellow illustrates the typical existing street cross section with the combined sewer system and the proposed alternative with the vegetated swale.
Stormdrain Sewer pipe
Existing combined sewer system.
Vegetated swale
Proposed alternative solution.
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TOPSOIL (PLANTING MIX) 0.3 M DRAIN ROCK (GRAVEL) 0.3 M
NATIVE SOIL PERFORATED PIPE (TO DRAIN INLET)
1.5 - 2 M
1M
2:1
VEGETATED SWALE DETAIL
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MA X
Extended detention aims at improving water quality. In the still water of a pond, solid sediment particles and the pollutants attached to them settle out and microbiota may begin to degrade some dissolved constituents. Improving water quality requires a longer ponding time than flood-control detention (Ferguson 1998). Extended detention basins can limit peak runoff flow, floods, downstream erosion, and control of pollutants such as suspended solids. This basin type includes a permanent pool of water. Another type are “dry detention basins� which can be covered with gravel. While basic detention ponds are often designed to empty within 6 to 12 hours after a storm, extended detention basins improve on the basic detention design by lengthening the storage time, for example, to 24 or 48 hours. Longer storage times tend to result in improved water quality because additional suspended solids are removed (EPA). The location of the detention basins is a relocation of the same treatment areas requirements noted on page 49 into public or not built parcels along the Ortega Creek in order to catch the flow from the vegetated swales. The stormwater runoff will be caught by the vegetated swales, slow down, partially infiltrate, cross the road adjacent to the creek through installed pipes into the detention basins (see page 56). In the detention basins there is an initial sedimentation basin to collect trash and debris. The water will then flow into the pool where it percolates through different layers of soil until it drains again through a pipe into the creek (see next page). In case of a bigger rainfall event the system is prepared to overflow without disturbing the overall functioning of the basin.
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Proposed location of the detention basins.
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Detention Basins
p a r t i c i p a t o r y s t o r m w a t e r m a n a g e m e n t f o r q u i t o e c u a d o r l a n d s c a p e a r c h i t e c t u r e & e n v i r o n m e n t a l p l a n n i n g p r o f e s s i o n a l p r o j e c t u n i v e r s i t y o f c a l i f o r n i a , b e r k e l e y 2 0 1 2
SEDIMENTATION BASIN
PERFORATED STANDPIPE BIORETENTION SOIL MIX 0.6 M
INLET
DETENTION BASIN DETAIL Dimensions vary according to location. Depth of detention basin is 1 meter minimum.
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GRAVEL 0.1 M CRUSHED STONE 0.3 M PERFORATED RISER
BYPASS
PERFORATED SUBDRAIN
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Vegetated swale Detention basin
Street Juan Vasquez
SCHEMATIC DETAIL OF CONNECTION BETWEEN VEGETATED SWALE AND DETENTION BASIN
Dimensions vary according to location.
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Vegetated swales Detention basins
OVERVIEW OF ENTIRE SYSTEM
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COMMUNICATION
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The idea of this proposal is to involve the community in the planning, building, and maintenance of this alternative stormwater system. There is a growing community interest in participating in these type of activities, a proof of that is the work of the ACMQ Solidaridad in the Ortega Creek. From the conversation with the EPMAPS it was clear their interest to also emphasize on the social aspect of the proposal and to include the community, since they wish to work on this with ACMQ Solidaridad. One of the concerns with these alternative stormwater solutions is how to convey the message of their value not only to the communities but to all the stakeholders, since they could be seen as merely aesthetic improvements. That is why a strong educational component has to be included in any such proposal, in particular, for developing countries where these solutions are inexistent. So how to explain the project? How to explain the natural processes and the problems driven from urbanization? How to make it accessible to everyone? That’s when the idea of creating a cartoon short story came about. The script is based on the idea of having a grandfather and his grandson sitting by the Ortega Creek and talking about its problems, causes, solutions, and the benefits of sustainable control measures in a non-technical speach. This communication piece will be published and distributed to schools, local neighborhoods and associations, other community organizations, etc. It is written to please and educate readers from all ages and it can be a powerful tool to create awareness of the situation and trigger an involvement process.
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one sunny afternoon by the ortega creek on the south side of the city of Quito...
... A LONG TIME AGO THE CITY WAS SMALL BUT IT HAS GROWN OVER YEARS AND YEARS, CAUSING A LOT OF CHANGES ON THE LAND.
1760 grandpa why is the creek so smelly and dirty?
1956
1983
1987
Today
well diego that’s a long story...
you see, when we build houses and roads we are hurting the natural water cycle...
huuh... I probably missed that day!
the water cycle?
you haven’t learn about that in school yet?
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hmmm... ok
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you see diego, our planet has a limited amount of water. water just keeps going around and around and around in what its called the
evaporation is when the sun heats up water in rivers or lakes or the ocean and turns it into vapor. The vapor then goes up in the air...
water cycle
this cycle is made up of evaporation, clouds, rain, and water in rivers, lakes and oceans.
the vapor in the air gets cold and transforms into clouds.
... plants lose water to vapor too!
when the clouds get too heavy it rains!
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rain may fall in water or it may fall on land. when it falls on land, it will either soak into the ground and become part of groundwater or it runs slowly to the ocean, lakes or rivers, and this is when the cycle starts again!
so what happens when it falls in the city?
so when the rain hits it it just...
in the city there’s a lot of asphalt and concrete...
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...wooo shes down!
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there’s more water running down causing floods...
dragging litter and other bad things to the creeks...
and by not soaking into the ground, less water will be available for plants and animals!
i guess no drinks tonight.
it is so ferocious that it eats away the land...
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and that is why the creek is so dirty?!
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yes diego, what is in the creek was washed from the streets around.
why don’t people do something about it?
they build pipes and sewers to send the dirty water to treatment facilities. there the water is treated and sent back to us.
so we just need to build more pipes!?
it’s not that easy diego. those solutions are expensive...
and as the city keeps growing more and bigger pipes will be needed... so when does it end? It’s a temporary solution. 65
well, people have been doing something...
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so what can we do about it?
that’s a good question diego. I know that in other cities people came up with alternative solutions
in many cities people have built natural systems to slow and clean the water on the streets.
really?
?
they are made of soil, rocks and plants...
the plants and soil allow water to infiltrate and at the same time they clean it.
we could build them in our streets too...
they become beautiful gardens where animals come to look for shelter and food.
... they are quite simple and prevent water from going into the sewage system. instead, the water flows naturally in these systems, gets cleaned and goes to the creek! 66
cool grandpa lets do it!!
p a r t i c i p a t o r y s t o r m w a t e r m a n a g e m e n t f o r q u i t o e c u a d o r l a n d s c a p e a r c h i t e c t u r e & e n v i r o n m e n t a l p l a n n i n g p r o f e s s i o n a l p r o j e c t u n i v e r s i t y o f c a l i f o r n i a , b e r k e l e y 2 0 1 2
CONCLUSIONS
p a r t i c i p a t o r y s t o r m w a t e r m a n a g e m e n t f o r q u i t o e c u a d o r l a n d s c a p e a r c h i t e c t u r e & e n v i r o n m e n t a l p l a n n i n g p r o f e s s i o n a l p r o j e c t u n i v e r s i t y o f c a l i f o r n i a , b e r k e l e y 2 0 1 2
The participatory stormwater management proposal as to be seen as pilot project of a partnership model of participation of all the stakeholders, the EPMAPS, the QZA, and other local intitutions, and the ACMQ Solidaridad, and other community organizations. The objective is to educate, plan, build, and maintain a sustainable stormwater sytem that restores the environmental quality of the area, by improving the water quality in the creek, mitigate floods, landslides and erosion, and contributing to a social, ecological, and recreational enhancement of the city.
Results Since the project has yet to be implemented there is no real data to measure. Although, the objectives and expected outcome for the control measures in terms of stormwater quality are the following: - 70% or more, total suspended solids removal; - 70% or more, lead and copper removal; - 60% or more, zinc removal; - 60% or more, oil/diesel removal; - Up to 100% fecal coliform removal. This is the main problem that is being targeted and to which there is a sustainable answer. The control measures will also reduce the peak flow from the streets, thus reducing the runoff erosive potential, local floodings and landslides. By preventing the stormwater from entering the sewer system, this will also alleviate the functioning of the system, diminishing the combined sewer dischages (CSDs) and localized flooding due to oveflow. It will also reduce treatment costs as the volume of water to treat will be considerably less.
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The main obstacles to this project were the distance to the study site and lack of some information which made it difficult to further develop the proposal and test other solutions. This will have to be done in the next phase of this project. Although, EPMAPS was extremely helpful in providing information and data, the distance and some technical communication issues delayed the project. This delay and lack of information made it impossible to present an integrated master plan for the neighborhood. The restoration of the existing pool, one of the community requests, could not be properly studied due to the lack of conclusive water quality results that constraint the choice of adequate control measures.
Recommendations This is a preliminary project. It has to be presented and discussed with all the stakeholders mentioned above. The hydrologic design and calculations also need to be verified on site. A landscape architecture master plan has then to be studied, presented and discussed again. It is the desire of the team that helped putting together this project to travel back to Quito and develop further this idea. It is also the EPMAPS objective to start implementing this project as soon as possible. The EPMAPS will receive this project, study it, and propose changes. Another aspect is the community perception and needs that can be adjusted and included in the project. For instance, urban farming is a popular land use in these peripheral areas of the city. It could definitely be a part of the project for potential multi-uses spaces along the creek. Other potential uses, such as recreational and educational, can be proposed to the community and integrated in the general master plan for the site. Thus, responding to different needs and increasing the value of the project.
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The stormwater system should be implemented at a very local scale. Ideally each drainage area should be an individual project. The organization of the community needs to be discussed with all stakeholders and planned according to their best interest. For instance, the OPP organized the community according to streets. The community outreach is the first step to involve the community and this can be done by distributing the communication piece in schools and locally through ACMQ Solidaridad. Involving children is essential to promote the concept and the project. Before implementation it is necessary to hold community meetings to further explain and revise the project. This is something that has been done in the Quitumbe Zone for other projects and for which EPMAPS and other stakeholders can start preparing. The materials to present in the meetings should cover, at least, the explanation of the ecological processes in the neighborhood, the alternative stormwater system solution, multi-purpose uses, and costs. Someone with a significant insight of the project and the functioning of these sytems should facilitate the meetings. Once the program is agreed a final estimation of costs must be done to evaluate the feasibilty of the project and stipulate who is paying what. The PSA of EPMAPS already expressed interest in including this project in their budget, but the community should also have a share of expenses and labor. To assure the efficiency of the project, once the first drainage area stormwater system is completed, the water quality must be regularly monitored. EPMAPS has qualified technicians and laboratories to perform such work. The results should then be presented to the community and general public as proof and as an incentive for the implementation of the system in other areas of the city.
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GLOSSARY
Erosion. Process by which soil and rock are removed from the land’s surface by water flow, and then transported and deposited in other locations. Flooding. Temporary inundation of all or part of a well defined channel or temporary localized inundation occuring when the surface water runoff moves via surface flow, swales, channels, and sewers toward well-defined channels. Infiltration. Process by which water on the ground surface enters the soil. Landslide. Down slope movement of soil and/or rock under the influence of gravity. The failure of the slope happens when gravity exceeds the strength of the earth materials. Peak flow. The highest flow over time. Runoff. Water that doesn’t infiltrate and therefore flows over the land. Stormwater. Water that originates during precipitation events. Watershed. A drainage area that discharges at one point.
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