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Planbook Introduction BACKGROUND In Los Angeles, the natural cycles of waste and water have been broken. In an urban system, unlike in a cyclical forest ecosystem, green waste is removed from the ground and shipped to landfills. Open space and waterways are paved, diverting stormwater to concrete channels and underground storm drains rather than letting it flow naturally back into the ground, starving the soil of life giving water while sending pollutants downstream to foul our beaches. Although reconnecting these broken natural cycles is a challenging task, the results will improve environmental quality, reduce government expenditures, create jobs, and foster more liveable neighborhoods. In the past, most environmental problems have been addressed in isolation, with little effective cooperation between jurisdictional agencies. Although some progress has been made, the Los Angeles region continues to struggle for solutions to domestic water shortages, landfill closures, urban run off pollution, flood threats and poor air quality. TreePeople, one of LA's oldest and largest environmental groups, has taken a step toward reconnecting these broken cycles by creating and leading the Transagency Resources for Environmental and Economic Sustainability (T.R.E.E.S.) project. This project seeks to unite various agencies in an effort to address shared concerns through using shared resources. The TREES project has the following goal: To show the environmental, economic, and social benefits of cooperative approaches to designing and managing our urban landscapes as functioning mini-watersheds. This project includes five integrated components. The first of these components, a four-day design charrette, was held May 14 to 18, 1997. This charrette produced design proposals for improving the environmental function of five typical Los Angeles-area sites. The second component of the TREES project is this PLANbook, which contains the results of the design charrette. The single-family home demonstration site is the third component of the comprehensive TREES project. The hydrological and ecological performance of this demonstration site will be monitored over the long term to help determine the problems and opportunities associated with treating each Los Angeles-area site as a mini-watershed. The fourth component of the TREES project is a cost-benefit model that will help decision-makers determine the cost savings that would result from employing the proposals outlined in this book (as well as other related strategies) so as to attain the maximum public benefit. The fifth and final component of the TREES project is an implementation plan, which will identify capital investment strategies for financing large scale retrofit roadblocks in the way of more responsible site management and ways to encourage property owners to make their sites more sustainable. THE SECOND NATURE PLANbook In this book we will illustrate practical design principles that could make every parcel in our region a healthy mini-watershed. We will attempt to show that by reducing each site's dependence on imported water and energy, we will also be reducing our regional water pollution and flooding problems. We will also demonstrate that the best and most economical way of tackling these interrelated problems is to focus on where they originate-at the beginning of the pipe, not at the end. We hope that this book will be of great use and interest to many groups and individuals: the government agencies that manage our environment; the politicians who struggle to develop ways to improve our environment; environmental groups who need communication tools and technical support; educators who work to teach people that environmental problems often begin and end at home; and, finally, to citizens who want to participate in making their local and regional environment a healthier place in which to live, work and play. The PLANbook is divided into three sections. The Introduction describes the environmental problems, along with the cost-benefit envelope, that the designs in the second section attempt to solve. The second section, Design, includes each charrette team's ideas for the five case study sites, including plans, sketch details, and preliminary cost-benefit assessments. The third section, Best Management Practices, includes five detailed best management practices (BMPs) for the single-family home site. THE DESIGN CHARRETTE: SECOND NATURE - ADAPTING LA'S LANDSCAPE FOR SUSTAINABLE LIVING The four-day Second Nature Design Charrette brought together engineers, landscape architects, building architects, urban foresters, and other experts to develop sustainable landscape designs for specific residential, commercial, industrial, and public properties that are representative of those found in the Los Angeles region. Most people are not familiar with the word "charrette." A charrette is a design activity in which participants are assigned a very complicated design project and are asked to complete it within a very short period of time. Members of the school of architecture at the École des Beaux-Arts in Paris coined the phrase at the end of the nineteenth century. The faculty at this school would issue problems that were so difficult that only a few students could complete them. When the allotted time elapsed, a push cart, or une charrette, rolled past the drafting tables where the students continued to work. The students would throw their drawings into the cart in various stages of completion, for to miss it meant an automatic grade of zero. The participants in the Second Nature Design Charrette produced the proposals and most of the illustrations contained in this book in a similar environment to that of the École des Beaux-Arts. We allowed them only three days to produce complete designs that would otherwise take several weeks or months. The "cart" came by at 5:00 p.m. on Saturday, May 17th, the evening of the charrette public presentation. Charrettes of this type have several major advantages over other problem-solving design activities. For one, they elicit the most creative solutions for addressing the most difficult problems, from the most accomplished designers, in the most compressed period of time possible. Under no other circumstances, would these individuals come together to stimulate each other, teach each other (and their student partners), and compete with each other to produce the best possible answers to a design problem. Charrettes also create an exciting and fertile atmosphere for collaboration between members of different disciplines. Too often these people don't talk to each other, even when they are working on very similar problems in the same location. Charrettes encourage members of different disciplines to communicate across the boundaries of their field in order to come up with holistic and appropriate design solutions. An important cautionary point must be made, however. Given the short time allowed, no one should think of the designs produced at this charrette as complete. It is especially important not to assume that the technical questions have been worked out to the point where any of these designs could be built as shown. Much more design and engineering work is required. These designs are beginnings, rather than endings, and they provide points of departure for later work. They demonstrate broadly applicable principles rather than describe specific plans relevant to specific sites. The exception to this rule is the TREES Demonstration Site, where many of the ideas from the Second Nature Design Charrette have been implemented. The plans for this site were later elaborated upon by a team of landscape architects and engineers before they began to renovate the site itself. A similar process would be required if any of the other four sites were retrofitted or if these plans were to be adapted for use at other sites. Charrette Goal The goal of the charrette is to demonstrate how retrofitting individual urban sites as functioning mini-watersheds would help to solve our region's most serious environmental problems. Charrette Objectives
Five design teams were assembled for the charrette. Each team included two landscape architects, one building architect, one civil engineer, and one urban forester or plant specialist. Many of the team members came from Southern California, others were recruited for their particular expertise from other parts of North America. Each of the five teams worked on a different site. We chose our five sites with the idea of providing a representative sample of the most common types of sites in the Los Angeles-area. These sites include a single-family home, a multi-family complex, a commercial and retail center, an industrial site, and a public school. Each team attempted to improve the ecological performance of its site with regard to each of the five environmental challenges discussed below. Each site had reasonable targets for water conservation, stormwater run off mitigation, air-cooling energy cost reductions, air quality improvements, and green waste reduction. These targets were based on the best data available and were keyed to publicly established targets for environmental improvement. FIVE ENVIRONMENTAL CHALLENGES FOR LOS ANGELES Challenge 1: Excessive Consumption of Potable Water Rates of Use Southern Californians have an almost unquenchable thirst for water. Our history is one of going longer and longer distances in order to get more and more water. All of the water imported to our region is fit to drink, yet less than 2% of it is actually consumed by humans. Almost all of the rest goes to flushing toilets, washing clothing, bathing, landscape irrigation, and industrial processing. All residential uses combined account for 59% of all water consumed in Southern California. The average use of fresh water per day is 256 gallons per dwelling unit with, on average, about 75 gallons per day being used for outside uses, primarily for irrigation. The commercial sector accounts for about 19% of all water used. The average use of fresh water is 80 gallons per day per employee, with 23 gallons of this being used for outside uses. The industrial sector accounts for about 6% percent of all water used. The average use of fresh water per employee is 103 gallons per day per employee, with 13 gallons of this being used for outside uses. The public sector accounts for about 6% of all water used. Virtually all of this water is used for irrigation. The remaining 9% is attributable to "unaccounted uses" (e.g. not metered, system losses, etc.). Cost-effectiveness Southern California water customers in all sectors are charged approximately $0.004 per gallon of water consumed. There is much debate about the extent to which this figure represents either the true cost of bringing a gallon of water to the consumer and to what extent this figure factors in the environmental costs to the various watersheds that are tapped for this purpose. Given this lack of clarity, and for the sake of this exercise, team members were told to feel comfortable valuing water at up to $0.01 per gallon. At that rate, an 80% reduction in off-site water imported for irrigation would be worth about $219 per year per dwelling unit. A 40% reduction in the volume of water imported for domestic consumption produces an additional benefit of about $264 per dwelling unit. These figures may serve as a useful guide in assessing the cost-effectiveness, over time, of the proposed solutions. Whatever the actual cost of imported water, the West Basin Municipal Water District is seeking to reduce water importation by 50% by 2020, at which time it is expected that the population of the region is expected to increase by over 25%. Obviously, the performance of the region's sites will need to improve dramatically in order to meet this goal. Reduction Strategies Employed by the Design Teams The five charrette teams suggested a variety of strategies for reducing water use. Low-flow showers, faucets, and toilets can dramatically reduce the use of water at little cost, and most teams assumed that this equipment would be installed. For site irrigation most teams adopted a strategy for capturing rain water in cisterns for later application to lawns and planting beds. The commercial site team suggested that the need for any irrigation could be virtually eliminated by using native plants, which, once established, can easily withstand the long summer dry season. Challenge Two: Flood Management The Los Angeles River has always been prone to flooding. Billions of dollars have been spent to channel this river in order to protect the valuable properties along its route. Presently, there is concern that in the event of a 133-year storm, the Los Angeles River will overflow its banks, inundating much of Los Angeles County in the process. Government officials have proposed adding concrete parapet walls to the river banks. These walls will rise up to 8 feet above grade along southern sections of the river and cost up to a quarter billion dollars. The existing system is no longer adequate because the Los Angeles urban landscape has become increasingly impermeable. Sites send stormwater into the storm drains immediately, taxing the Los Angeles River's flow capacity as soon as it rains. If this discharge rate can be reduced, and the flood level lowered, then the present system could handle a major rain event such as a 133-year storm. Run off Rates Presently, downtown Los Angeles averages about 80% impervious material. With this degree of impermeability, the peak run off rate per urban block (300 X 600 ft.) is 2,020 gallons per minute. Compare this with Hacienda Heights, which averages about 30% impervious material. Hacienda Heights has a peak run off rate per urban block of 1,257 gallons per minute. Reduction Strategies Employed by Charrette Design Teams The storms that cause the most damage occur after a series of back-to-back storms when the ground is saturated and when even lawn surfaces have run off rates approaching those of asphalt. Teams were asked to plan for this "worst-case" situation, as it represents the conditions under which floods occur. The Army Corps of Engineers uses a 133-year "design storm" of 9.78 inches in a twenty-four-hour period. The alternative systems proposed by the charrette design teams were designed to hold at least three inches of this 133-year design storm, since a 30% reduction in peak run off throughout the LACDA area would obviate the need for the parapet walls on the Los Angeles River. All five teams included some kind of hybrid cistern to both conserve water and to partially alleviate flooding. Cisterns that collect rain also reduce the amount of water flowing to the rivers, and thus help alleviate flooding. All five teams also made changes that enhanced their respective site's performance with regard to flood management, only. Generally, these changes had to do with strategies that held water in the soil, in the plants, in mulch beds, in infiltration and recharge basins, and in other inexpensive locations where later retrieval was not a concern. Since the rains that cause flooding come almost entirely during December, January, February, and March, the problem becomes one of balancing the desirability of storage capacity against the desirability of limiting cost. Each team struggled to reserve cistern or dry well capacity when floods threatened. Most teams developed ways to empty these storage areas in advance of flooding, so that storage areas would be available when needed the most. Cost-effectiveness The cost effectiveness of on-site flood management strategies is very difficult to calculate; however, for our purposes we determined that if on-site storage systems were widespread enough to reduce peak urban run off rates during storm events by 30%, then the parapet walls being built on the Los Angeles River would no longer be required. We estimate that there are about one-quarter million acres in individual sites in the urban portion of the Los Angeles River watershed, and we accept the projected cost for the parapet walls to be a quarter billion dollars. Therefore the value per acre in avoided public costs of water holding systems would be $1,000. While this number probably will not, by itself, "pay" for the on site-storage system, it can, when combined with other benefits in other areas, be of considerable importance. This figure includes neither the value of reducing the strain on existing drainage systems (ie., those not needing upgrading) nor the value of avoiding the more frequent threats of local area floods on the Los Angeles River tributaries and channels that would be the result of adopting these strategies on a wide scale. Presently the flood management system for the Los Angeles River tributary storm lines and channels is designed to accommodate only the 25 year flood. This analysis suggests that local area flooding will occur with much greater frequency than will wide scale inundation from the Los Angeles River. On site retention of stormwater would, logically, be even more effective at preventing frequent and very costly local area flooding. Challenge Three: Water Pollution Most urban stormwater run off flows directly into the San Pedro and Santa Monica Bays without being treated. The suspended solids, trash, faecal matter (mostly from pets), and chemicals (mostly from cars) that sit on the region's sites and streets are washed into the storm drains with the first winter rain. The first strong rain of winter always causes the most problems at the beaches, forcing frequent closures. In 1995 the beaches of Santa Monica Bay received an "F"-rating on 39% of the days that it rained. If present trends continue, the number of "F"-rated days is expected to rise to 52% of rainy days by the year 2020. On most rainy days far too much water is discharged into the bays to be effectively treated. Some treatment capacity has been, and will continue to be, installed to treat water that flows in the system on "dry flow" days. However, this limited treatment system will, at best, solve only a small part of the problem. Reduction Strategies Employed by Charrette Design Teams All design teams incorporated strategies, systems, and devices for pollution mitigation. In most cases they were integrated with design strategies employed for water retention and flood management. In some cases polluted water from nearby streets was taken onto the site and bio-remediated. Design strategies include, but were not limited to, vegetated swales and filter strips, recharge areas located under parking lots, holding tanks and cisterns under playfields, surface area holding ponds, turf grass filters, and riparian retention and treatment areas. Cost-effectiveness The cost effectiveness of pollution control strategies is difficult to quantify, as no one has seriously considered alternatives to off-site end-of-the-pipe strategies for solving this problem. Plans exist to use "excess" capacity in sanitary treatment plants to treat stormwater when flow rates are low (eg., residual flows, groundwater seepage, hydrant flushing, water from resident's washing cars, some industrial water wastes, etc.). The cost of treating stormwater in central facilities will likely be close to the cost of treating an equal amount of sanitary waste. The cost of treating sanitary waste is now estimated to be approximately $1.37 per 100 cubic feet. Assuming that the average urban site has a run off coefficient of 0.7, every 1 acre of urban land discharges 38,088 cubic feet of water into the storm system per year. The cost of treating this amount of storm discharge would therefore be $522 per acre per year. It should be noted that no one is seriously considering treating all of the stormwater discharged from these sites; at most, officials are proposing to treat the first tenth of an inch of each storm. Clearly, this end-of-the-pipe strategy will not solve the problem of water pollution in the bays and on the beaches. Without some way of controlling the lion's share of this discharge, by the year 2020 we can expect the beaches of Santa Monica Bay to be unswimmable on more than half of the days following storms and on 15% of dry days (two to three months per year total). Thus, it seems clear that if this problem is to be solved at all, it will be solved on the urban sites and city streets where it originates. Challenge Four: Building Energy Use In Los Angeles more electric energy is used to cool buildings than for any other purpose. The demand for cooling is not spread evenly over the year or evenly over the day. The peak demand occurs when it is hot outside, and everyone turns on his or her air-conditioner at once. During peak periods, over 40% of electricity consumed goes to air-conditioning. The electrical system that serves the region must be built to supply this peak demand. New capacity is always being added to the grid for this purpose, and such additions are many times more expensive per unit than is maintaining the old capacity. Thus, the real cost of the energy needed to supply this peak demand is much greater than is the average cost of electric energy. Meanwhile, those who live far from the cooling Pacific breezes and who cannot afford (or do not choose to have) air-conditioning bake in poorly designed and unshaded homes. Finally, power plants are major producers of CO2, the "greenhouse gas" produced by burning fossil fuels. Reducing our production of greenhouse gasses to 1990 levels, as required by the Tokyo treaty on global warming, would be facilitated if we cut our peak demand for air conditioning. Trees and vines can be the means for this reduction. Reduction Strategies Employed by the Charrette Design Teams This charrette focused primarily on site-related retrofit strategies rather than on construction techniques for the buildings themselves. Designers were asked to explore ways of reducing peak-load energy consumption, primarily through the use of on site systems, site structures, and plants. Since air temperature affects cooling demand, designers used heavy tree planting to reduce the ambient air temperature, not just on the site, but also throughout the city, in an attempt to reverse the energy-wasting heat island effect. Dramatic improvements in our local climate would result if most of our city's sites included large shade trees. For example, neighborhoods in Houston that still retain a virtually continuous overhead canopy enjoy air temperatures several degrees lower than those of the adjacent downtown area. Each degree reduction in air temperature significantly reduces the demand for air-conditioning. Ironically, in Los Angeles, where plants seem to be everywhere, a very small percentage of the land surface is shaded by trees. In residential areas the figure is less than 20%, and in commercial and industrial zones there is virtually no tree canopy at all. The average canopy cover in the City of Los Angeles is about 10%. Preventing the direct rays of the sun from striking the building is even more important than is lowering ambient air temperature. In the summer months, when cooling demand is greatest, the sun strikes east and west walls for many hours, heating building surfaces to temperatures far above that of the air. Much of this extreme heat build-up is radiated back into the structure. Peak cooling energy demand occurs in the afternoon, when the sun is striking west facing walls; thus, it is especially critical to protect these particular walls. The strategic planting of trees is the most effective means of shading building surfaces from the sun. Vine-covered trellises, as well as vines that adhere to building surfaces, are also effective if planting trees is either not possible or is otherwise inappropriate. All five design teams found ways to add green to their sites, thus cooling and moisturizing the air, providing shade, and lowering energy use. Cost-effectiveness Emerging research allows us to quantify some aspects of the cost benefits associated with tree planting. Generally, tree planting has two benefits: the reduction of pollution and the reduction of energy demand for heating and cooling. On average, mature urban trees reduce the amount of carbon dioxide (CO2) in the air by about 115 pounds per year. They do this in two ways: ( 1 ) by using CO2 in photosynthesis, and ( 2 ), by lowering the amount of CO2 released into the atmosphere by power plants by reducing demand for electricity through shading buildings and lowering air temperatures. Of ( 1 ) and ( 2 ), ( 2 ) is many times more important per urban tree than is ( 1 ). The California Energy Commission has estimated that reduced CO2 emission has a dollar value of $920 per year. Thus, for the purposes of this charrette, it was suggested that each tree has a yearly value of $52.90, or a "lifetime" value over a thirty-year "amortization period" of $1,587. This value is far in excess of the cost of installing a shade tree. Challenge Five: Green Waste Green waste consists of grass clippings, leaves, and branches removed from sites as part of normal landscape maintenance. On average, each household in the Los Angeles region generates 1.3 tons of green waste per year. This represents roughly a third of all household waste. Removing organic material from sites prevents trees from recycling their own detritus. In forest systems, the forest floor is thick with decayed remnants of leaves and branches. This thick organic layer (humus layer) eventually decays and returns to the tree as food. It also improves the structure of the soil over time, making it increasingly capable of supporting trees. Urban trees would be healthier if this natural cycle could be emulated. Thirty-three percent less waste would be delivered to the landfill if green waste was somehow returned to the soil of the site. The often heavy and sterile soils of the Los Angeles region would gain improved fertility, aeration, and water-storing capacity if green waste was allowed to work its way back into the soil. Reduction Strategies Employed by the Charrette Design Teams Systems, areas, and devices for returning composted waste into the soil are a feature of each of the designs. In some cases mulch beds do double-duty as water storage areas. Deep mulch beds can store copious amounts of water (up to 60% of their volume) and hold it for a very long time. It was suggested that plants capable of withstanding this unusual hydrological situation be employed in these areas. Cost-effectiveness Direct cost-benefits associated with keeping green waste on-site are not insignificant. The cost of hauling and tipping the 1.3 tons of green waste generated by the typical Los Angeles region dwelling is $81 per year. This figure does not include labor costs related to gathering and collecting the waste for pickup. On a per-acre basis, a figure of $648 for a typically landscaped site (the school site, for example) can be used as a reasonably accurate guide to cost. Perhaps of more significance, the Southern California Association of Governments is committed to steady increases in the percentage of household wastes recycled. Presently, 25% of all household waste is recycled. The plan calls for that figure to rise to 67% by the year 2020. These reduction targets have been given the force of law in AB 2020, the legislation that requires all solid waste to be reduced by 50% by the year 2020. If that target is to be reached, virtually all green materials will need to be kept out of the waste stream. The only truly logical place to put this "green waste" is back on the site, thus transforming green waste into a "green resource." THE DOLLAR VALUE OF ENHANCED ECOLOGICAL PERFORMANCE We might all agree that no one can really put an accurate dollar value on the environment. However, in the absence of an ascribed dollar value, the cost of environmental impacts have, until recently, been pencilled in at zero. But with an environmental crisis becoming more and more immediate, many of the direct costs of our wasteful practices are becoming evident. For this charrette we used the direct costs that were available as the basis for our cost-benefit framework. In some cases, when there were no actual costs available (e.g., stormwater pollution), we used the costs of mitigating analogous environmental impacts (e.g., septic discharge). We believe that our approach to determining costs is quite conservative; most experts who attempt to ascertain the "full cost" of environmental degradation place it much higher. Yet even on the conservative basis of immediate and avoided costs, a strong argument can be made for the cost-efficiency of the designs presented in this book. A "full-cost" assessment would only make our argument many times stronger. We used our best estimate of immediate and avoided costs per unit improvement in each of five environmental issue areas. Each team was challenged to enhance the ecological performance of its site based on the size of their respective sites. Upon successfully meeting the performance thresholds for each of the five issue areas, they were able to rationalize spending up to about $202,800 per acre for the strategies, systems, and devices needed to bring about performance improvements. We compiled all of the cost-benefits per unit performance improvement (discussed above) on the matrix shown below. This matrix was provided to each charrette participant and established the cost-benefit envelope for each team's design proposals.
SECOND NATURE DESIGN CHARRETTE COST-BENEFIT MATRIX
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