Toward Sustainable Communities

After mountain man Joe Walker rode horseback over the Sierra Nevada in November 1833 and discovered the giant redwoods, he descended through tangled foothill forests into the spacious oak parks and grasslands of the valley floor. Behind him, the mountain wall reared up, wringing moisture from the air masses that ascended its bulk from the Pacific and letting it go in tumbling rivers that watered California’s golden valley.Eight generations later, a person pounding down the Interstate 5 corridor might see only glimpses of the staggering natural bounty that led to the settlement of the Central Valley. It is ironic that development can consume the beauty of a landscape to the point that it loses the qualities that first drew people there. But there is hope for more enduring landscapes in the future, for the challenge of accommodating the population of this next century presents us with the extraordinary opportunity to design and build sustainable communities.Today 34 million people live in California. On a nighttime flight over the metropolitan areas of the great valley, the glittering grid that spreads mile after mile in the darkness below is a grim reminder of millions of kilowatts of power required to light this network of civilization. If we are flying by day, the miniature landscape that glides by below-with its antlike cars on the lattice of roads and its neat neighborhoods quilted with green lawns-has a gamelike quality. But as anyone who has worked as a planner or fallen under the spell of a session with Sim City knows, balancing the demands for infrastructure, water, fuel, jobs, and resources to support a megalopolis can be daunting. While some areas flourish, others fall into decay and are abandoned. The trick, of course, is to make everything work at once without having to continue to build anew.The New Math of Ecosystem ServicesThe concept of sustainable development is not new. It has been one of the special domains of planning, architecture, and landscape architecture for many years. Most of us can point to a structure in our neighborhood or business district that was built with conservation in mind: a solar house, a library constructed in an insulating outer envelope, or a building designed to withstand heat in summer and conserve it in winter. Until recently, such stand-alone ventures have been thought not to compete successfully with the economics of mass construction that rely on pattern book house plans, standard materials, and coin-of-the-realm construction methods. But, as people engaged in environmental economics increasingly agree, this depends on how you do the math.Consider, for example, the way we build new neighborhoods: Mass grading allows an economy of scale so that standard floor plans and foundations can be fit easily to the ground, resulting in savings for developers and home buyers alike. But preparing lots in this way results in other expenses for new homeowners: soil amendments and nutrients, plants, labor, applications of water, and the costs of ongoing maintenance to reestablish and maintain vegetation where, just recently, native plants thrived. These activities support the garden store at the foot of the newly graded hill where the new neighborhoods have just been built, but they do not immediately result in recovery of the predevelopment landscape services.Break-Even Points Are ChangingToday environmental economists are looking beyond direct-vs.-indirect development costs and discovering new break-even points for investment in conservation. They are calculating the dollar value, over time, of the ecological services provided by healthy soils and plant associations. These services include rainfall interception, modulation of air and water temperatures, infiltration of stormwater, and the buffering effects of natural areas on streams, wetlands, and wildlife habitats. If we can assign actual dollar values to these services, these costs can be used as a basis for allocating expenditures on conservation-conscious development and redevelopment.Unintended Consequences

Conifer trap stormwater on their needles, which buffers urban stormwater systems from flashy storm flows and their effects.The relatively recent urban goal to protect ecosystem services arises from studies that show the tremendous expense of environmental impacts stemming from centralized stormwater collection. In a typical curb-and-gutter neighborhood, such as the new neighborhood described above, stormwater is collected and piped to a discharge point, usually the nearest stream. EPA has found that runoff of pesticides, herbicides, nutrients, and pet feces from many such neighborhoods contributes to eutrophication of lakes and streams and to the degradation of aquatic life, drinking water, and water-based recreation. Add to this the water-pollution impacts of the materials shed by cars (hydrocarbons, metals, and asbestos from the linings of brakes, for starters) and the costs of these impacts on the health of people, wildlife, and aquatic systems. Consider the erosion of channels forced to accommodate more frequent and higher flows from rapidly draining impervious surfaces. Viewed in this light, the efficiency of curbs, gutters, and piped stormwater drainage systems does not seem as cost-effective as once thought.On a winter morning’s flight over the Los Angeles Basin just after a heavy rainfall, a person can peer down and see sunlight flashing on thin sheets of water held for a moment or a few hours on millions of parking lots, roads, lawns, and rooftops. Some say that if the roughly 15 in. of precipitation that falls on this megalopolis each year could be stored, it could satisfy half the region’s water needs. Yet a network of storm canals, curbs, gutters, and sewers hurries this precious commodity to the Pacific Ocean where the polluted stormwater forces health warnings and beach closures. In the age in which dilution has been the solution to pollution, the reality of contaminated beaches hits home hard. We are tempted to think that the ocean is so large, it would be almost impossible for people to affect its quality. But studies conclude that runoff from storm drains, streets, and highways; livestock operations; sewage plants; agricultural fields, lawns, and golf courses; and eroding ditches and streams is contaminating shellfish, causing gastrointestinal diseases in swimmers and algal blooms and hypoxia in coastal waters. In the nearshore zone of the Pacific Ocean off the LA Basin, trash itself recently has been named an element of water-quality impairment.Almost everyone loves a trip to the beach. EPA reports in Liquid Assets 2000 (www.epa.gov/water) that one-third of all Americans visit coastal areas each year, largely as ecotourists, to fish, walk along the beaches, and visit wildlife areas. For these coastal pleasures, American tourists spend about $44 billion annually, a sum that clearly speaks for the value citizens place on a healthy environment.It Starts at Home

Undisturbed natural areas along urban stream corridors provide much-needed sanctuaries for people and wildlife.

Although it is important for people to be able to visit clean lakes, rivers, and coastal areas, in the cities of the 21^st century, it will be essential for people to be able to enjoy healthy ecosystems close to home. As the population swells, clean water and aesthetically pleasing greenspaces will be evermore important attributes of the everyday quality of neighborhood life. People will walk, jog, play, and ride bikes in nearby multifunctional linear parks and greenways where natural areas soften the visual impacts of urbanization and provide wildlife habitat and passive stormwater treatment and infiltration.These concepts create a remarkable opportunity to retrofit existing urban places. Model retrofits are being undertaken in Los Angeles by T.R.E.E.S. (Trans-Agency Resources for Environmental and Economic Stability), whose mission is to create cross-jurisdictional and cross-disciplinary connections between people and institutions responsible for components parts of the urban ecosystem. TreePeople (www.TreePeople.org) helped coordinate a round of charrettes focused on retrofits for a range of urban sites. Five design teams participated, each with two landscape architects, one building architect, one civil engineer, and one urban forester or plant specialist. The teams were charged to develop cost-effective reduction strategies to improve their sites’ ecological performance. They came up with strategies to reduce waste or minimize resource degradation. These are summarized in the table below. Table 1. Strategies to Improve Site Ecological PerformanceChallenge Strategies to Reduce Waste or Degradation of Resources Excessive consumption of potable water “¢ Install low-flow showers, faucets, and toilets.“¢ Capture rainwater in cisterns for later application to lawns and planting beds.“¢ Use native plants to eliminate need for irrigation after plants are established. Flood management“¢ Capture at least 3 in. of large storm events in cisterns.“¢ Hold stormwater on-site in soils, mulches, plant beds, and infiltration and recharge basins. Water pollution “¢ Integrate water pollution – control strategies with strategies for water retention and flood management.“¢ Implement vegetated swales and filter strips, recharge areas under parking lots, holding tanks and cisterns under play fields, surface-area holding ponds, turfgrass filters, and riparian retention and treatment areas. Energy use by buildings “¢ Reduce peak-load energy consumption by means of onsite systems, site structures, and plants.“¢ Reduce heat island effect of site and surroundings by means of heavy tree plantings.“¢ Protect east and west building walls from direct rays of the sun by means of trees and vine-covered trellises. Greenwaste “¢ Keep greenwaste on-site. Summarized from Second Nature: Adapting LA’s Landscape for Sustainable Living by TreePeopleThe teams then calculated the dollar value of direct costs that would be saved by implementing the strategies for enhanced ecological performance. These amounts are shown in Table 2, below. Table 2. Cost-Benefit MatrixIssue Amount Changed Unit Estimated Value per Year Estimated Value per 30 Years Estimated Value of 30-Year Value per Acre¹ Water for irrigation 80% reduction Per dwelling unit $219 $6,570 $52,560 Water for domestic consumption 40% reduction Per dwelling unit $264 $7,920 $63,360 Flood management Hold 3 in. of water during flood emergency Per acre $1,000²(parapet walls) $10,000³ $10,000⁴ Water pollution Bioremediate all first-flush water on-site Per acre $522 $15,660 $15,660 Air pollution Strategic shade for structures, general planting for heat island Per acre, 20 trees strategically placed at $52.90/tree $1,058 $31,740 $31,740 Greenwaste Recycle all greenwaste on-site Per dwelling $81 $2,430 $19,440 Total value of all remediation strategies to apply to construction and maintenance per acre: $192,760 Source: Second Nature: Adapting LA’s Landscape for Sustainable Living by TreePeople¹For simplicity, this 30-year amortization figure assumed zero interest and constant dollars.² This figure was derived just from the cost of the concrete parapet walls proposed for the Los Angeles River. No costs for local flooding or for sizing storm systems for quick discharge are included. Real costs are much higher.³ Assumes the inclusion of other end-of-the-pipe investments required during this period.⁴ This figure is not changed since we are assuming the savings derived by not installing the concrete parapet walls are a one-time-only occurrence.

Undisturbed soils and native vegetation play important roles in runoff management and infiltration.

Some low-volume roads can be designed to support vehicles while serving as BMPs to facilitate stormwater infiltration.Together the strategies comprise a set of guiding principles and BMPs for retrofitting urban sites so they can function as miniature urban-forest watersheds. This is exciting to Andy Lipkis of TreePeople, who notes in his introduction to Second Nature: Adapting LA’s Landscape for Sustainable Living, “Urban and community forestry hold the key to saving our cities in ways we could not have envisioned 25 years ago…. What began as simple tree planting has grown into a project that extends to urban infrastructure management.” Lipkis notes that these new practices will require profound new levels of education. They will cast individuals and families in the role of landscape stewards and allow agencies to serve as educators, facilitators, and monitors rather than enforcers.And they will cost money. But in light of recent findings by Tom Schueler of the Center for Watershed Protection (The Economics of Watershed Protection [http://cwp.org]), and the Institute for Southern Studies (Green and Gold), environmentally sound policies and healthy economies tend to go hand in hand. And when economies of scale can both conserve natural resources and reduce society’s costs for their consumption and management, savings for ratepayers and utilities can be profound.TreePeople demonstrated this in the LA basin’s Sun Valley watershed, where a $42 million flood-control channel had been in the works. They invited utility stakeholders to design a project to capture and recycle the runoff instead. After considering energy, water quality, and water supply, stakeholders opted to invest $100 million for a sustainable project that would reap $500 million in benefits. Lipkis was delighted. “This raises the crescendo on the symphony of sustainable development. Money always seems available to construct large-scale public infrastructure projects that attempt to solve problems caused by urban development. A sustainable environment requires that we stop the leaking away of our natural resources-including wildlife, nutrients, energy, money, water, and the energy of people. We must begin to spend public money in a way that integrates the management of all of our resources so we can build a beautiful, sustainable environment and enjoy a thriving economy.”