Sustainability and Site Design PDF

CHAPTER 1 Sustainability and Site Design H umans have a significant impact on the world environment. It has been said that 60 percent of the earth’s land surface is under the management of people but that 100 percent of the world is affected by the practices of that management. Whether we are aw...

CHAPTER 1 Sustainability and Site Design H umans have a significant impact on the world environment. It has been said that 60 percent of the earth’s land surface is under the management of people but that 100 percent of the world is affected by the practices of that management. Whether we are aware of it or not, our activities have an effect on the world. Paul Erhlich and John Holdren (1971) used the formula I = PAT (Impact = Population × Affluence × Technology) to illustrate the relationship of people, per capita rate of consumption, and the economic efficiency of consumption. Although the United States has more efficient and cleaner technologies than some nations, these benefits may be offset by the rate of consumption afforded by its relative affluence. Even though China has many more people, their relative affluence and level of technology were low historically, but China’s affluence and technology level have been increasing rapidly in recent years. In either case the environmental footprint is significant. In 1987 the Brundtland Commission published Our Common Future, which recognized that to avoid or at least minimize the environmental impacts of human behavior it is necessary for society to adopt a sustainable approach to development. Sustainability was defined as “meeting the needs of the present without compromising the ability of future generations to meet their own needs.” In February of 1996 the President’s Council on Sustainable Development (PCSD) published Sustainable America—A New Consensus for Prosperity, Opportunity and a Healthy Environment for the Future. The PCSD identified 10 goals, but the first 3 really encompass them all: health and the environment, economic prosperity, and equity. Equity refers to social equity (equal opportunity) and intergenerational equity (equity for future generations). To meet the challenges of sustainability we need to change our behaviors—to adapt to a paradigm of economic prosperity, social equity, and environmental sustainability—but these goals have traditionally been viewed as antagonistic or mutually exclusive. We tend to think in extremes: the worst of economic activities compared to the best of the environment, or the most restrictive impact of environmental regulations and resulting dire economic consequences. Economic health and environmental sustainability are not mutually exclusive. The challenge we face is to reconcile our economic interests with our environmental interests. We have learned that gains or improvements in one area may be offset by increases in another. Between 1980 and 1995 per capita energy consumption in the United States fell, but total energy consumption increased by 10 percent due to a 14 percent increase in population. From 1995 to 2005 the per capita trend in energy has been flat, perhaps 1 2 Chapter One even declining a bit, but as the U.S. population increases at a rate of about 3 million people per year, total energy use rises as well. Likewise, although modern cars are 90 percent cleaner than cars built in 1970, there are so many more of them that the efficiency gains are offset to some degree by the increase in the volume of pollution. The impacts of development and land use patterns were well documented during the last half of the twentieth century. Impacts include a loss of water quality, fragmented and lost wildlife habitat, human health issues, introduction of invasive exotic plants, loss of biodiversity, falling groundwater tables, and more. A 2007 University of Ohio study found that landscape fragmentation—the loss of cohesive patterns of connectedness in a landscape—had increased 60 percent between 1973 and 2000 (Irwin and Bockstael, 2007). Fragmentation is known to be closely associated with a loss of biodiversity and resilience in landscapes. As development proceeds, isolated “islands” of green space and narrow visual buffers give some aesthetic appeal to the finished site, but they are commonly without significant ecological value. A variety of studies and reports detail the public and personal health impacts of some development patterns. Human health impacts range from obesity, hypertension, and respiratory problems to mental health concerns. The causes are equally diverse and include reduced air quality, traffic noise and vibration, sedentary lifestyles, and a loss of social capital. Public costs are higher as well. Numerous studies have found that suburban development as it is typically done does not raise sufficient tax revenue to pay for itself and so drives the need for higher taxes for existing communities. Goetz, Shortle, and Bergstrom (2004) summarized more than one hundred studies and found that for every new dollar of revenue raised by development $1.11, on average, was spent providing services to those same developments. A Maryland report found that school bus budgets in that state more than doubled to $492 million from 1992 to 2006, yet the miles driven by buses increased only 25 percent (Sewell, Ahern, and Hartless, 2007). Although some states have laws that allow impact fees, even a quick analysis reveals that these sorts of ancillary costs usually are not captured by them. In addition to these local impacts, human activities are having significant affects on global climate. People around the world have become more aware and concern is being turned into action. This awareness is made more critical by the population increases expected in the coming decades. The United States currently has a population of more than 300 million people and is expected to grow to between 420 and 438 million by 2050, an increase of nearly 3 million people per year. It is expected that 20 percent of the U.S. population in 2050 will be foreign-born legal residents and that 82 percent of the increase in population will be due to immigrants, their children, and their grandchildren. To respond to this population increase, it is necessary to build the equivalent of a city the size of Chicago every year going forward. What will that development look like? About 80 percent of the buildings in the United States have been built since 1960. Buildings are responsible for 48 percent of the increase in greenhouse gases produced by the United States since 1990, an increase greater than emissions from either industry or transportation. A building constructed in the European Union typically uses about 25 percent of the energy of a similar building in the United States. The patterns of growth in the United States have changed as well. Sewell, Ahern, and Hartless (2007) found that today most suburban development or sprawl is occurring in bands located 55 to 80 miles from urban centers. This pattern of growth has been underwritten in part by road improvements that enable people to live further from the city centers and Sustainability and Site Design encourage more driving and more energy consumption. A study of land development by Woods Hole Research Center (2007) found that development in the study area had increased 39 percent from 1986 to 2000. The center concluded that we should expect a 60 percent increase in total development in metropolitan areas by 2030. The environmental, economic, energy, and public health issues resulting from development as it has been done since 1960 provide a compelling argument that change is required. Much of the growth in the United States is not a function of population growth, however. Several studies have looked at the trends in growth and found that only about 50 percent of U.S. development can be explained by population growth (Pendall, 2003; Kolankawicz, 2007). What is worse is that states with growth control programs and legislation seem to fare no better than states without such controls when it comes to limiting sprawl (Anthony, 2004). These patterns of development and land use are clearly unsustainable, yet much of existing public policy is focused on encouraging and subsidizing such growth at the expense of existing urban areas. Community leaders are frequently seen in local papers turning over a spade of earth to celebrate new business outside the existing urban center. The new facility, often with tax incentives of one sort or another, will draw employees to it, create traffic, require new infrastructure, and generate housing at the expense of the existing community. New roads must be constructed and sewers and water lines extended, and with new housing come the need for schools and community services. Very often this growth is unaccompanied by real population growth; more land is consumed to support the same number of people. If sustainability is the objective, these events might better be viewed as failures of planning rather than successes. Generally it takes 20 to 30 years for technology to move from the research and development phase to use in the land development and construction field. Reasons for the lag time vary but include developing the awareness and demand necessary to bring along ordinances; however, a more common reason is the natural and predictable resistance of people to change. The various parties to development all bring their own interests to the process, and, in turn, each stakeholder assesses development differently: how will the site fit into the community, will it be a financial success, does the plan meet code and ordinance? It is the job of the designer to find the synthesis of all these often adversarial views. The designer also has the greatest opportunity to innovate and introduce alternatives to the planning and design of sites and landscape. With a duty and responsibility for the health and safety of the public, the professional designer has the burden to make the site “work.” With the realization of the impacts of site development, introducing alternative, more sustainable practices to site development can best be done by site design professionals. Regulatory agencies may create a framework for more sustainable design practices, but in the final analysis the site design professional must implement these guidelines. Public officials and reviewers, however, share responsibility in educating the public and elected officials regarding the importance and desirability of change. Our experience with change is largely based on introducing new materials or methods into design and construction. The change required by the introduction of new regulatory or permitting programs is a familiar experience for most of us. Contemporary site planning and design is changing to adopt into practice much of the knowledge and information gained as our awareness of environmental risks has improved (Table 1.1). Sustainability requires a broader and deeper view of site planning. The leadership of this change is coming from many different places, but changing emphasis may require 3 4 Chapter One High-risk problems Medium-risk problems Low-risk problems Habitat alteration and destruction Herbicides/pesticides Oil spills Oil spills Species extinction Toxins, nutrients Groundwater pollution Overall loss of biodiversity Biochemical oxygen demand and turbidity in surface water Radionuclides Stratospheric ozone depletion Acid deposition Acid runoff to surface water Global climate change Airborne toxins Thermal pollution Adapted from The Report of the Science Advisory Board Relative Risk Reduction Strategies Committee to the EPA (Washington, D.C.: U.S. Government Printing Office, September 1990). TABLE 1.1 Relative Environmental Risks as Ranked by Scientists many of us to reevaluate our past work and assumptions and begin to approach design differently. There can be a great deal of resistance to such change; methods and principles that have been acceptable in the past and that we thought were successful may have to be abandoned for other methods and for new ways of thinking. Some of the logic we have used to plan and design sites will be augmented with new and additional considerations. In some cases it may be replaced entirely. It is difficult to objectively study the impacts of past practices and not recognize that a new paradigm is in order. If we are to build the equivalent of another Chicago every year to respond to our growing population and minimize the impacts of doing so, the practices we follow and the principles we employ must change. During this period of change, the design principles of land development in a sustainable postindustrial society will be determined. It is an exciting time for design professionals. In the United States site design has always been an issue of local control and practices because, in part, the conditions and needs of local communities and landscapes are too diverse to be addressed in any single ordinance or set of regulations. Nonetheless, common, if not universal, practices and methods have served design professionals and communities well. The increasing awareness of the need for more sustainable land development includes emergent practices that also have broad application and value. In recent years the federal government and many states have passed incentives to encourage green building. Some states offer tax incentives to encourage energy efficiency and the use of green methods and materials. It is a practical certainty that being able to provide such service to clients will be a competitive necessity in only a few short years. It is through the design professions that these changes to land development, site planning, and design will be introduced to most communities. This is the subject of Chap. 2. Population and Demographics Trends in population and demographics have important implications for planners, and the U.S. population is projected to increase to at least 420 million by 2050. Much of the population growth in the United States is occurring in the southwest and southeast. Known as the Sun Belt, much of this area is semiarid to arid land where water may be Sustainability and Site Design FIGURE 1.1 Dryscaping for a desert home reduces the need for water and other inputs to maintain a healthy and attractive landscape. in short supply. Shifts in populations will put increasing pressure on existing supplies and require more conservation. Dryscaping and infiltration of storm water are already becoming standard practices as part of conservation efforts (Fig. 1.1). The emergence of energy as an issue in California in 2000 and 2001 is an example of the complexity of the problems we face. Consumers are interested in access to affordable power but have been reluctant to authorize construction of new generating plants. Clean alternatives for generating electricity, such as wind generators and large solar installations, often have met with local resistance. Although conservation has not been a significant part of our national strategy, designers might anticipate more opportunities for innovation in site design that contribute to energy efficiency as well as water conservation. Conservation-related design is viable because it pays for itself and contributes to the bottom line of business. According to the U.S. Census, 77 million people in the United States were over 50 years old in 2000. In the midwestern and northeastern states populations are growing older. In some northern states the number of births per year is less than the replacement level, and these states may experience a decline in population as other parts of the country expand rapidly. Florida is well known as a retirement destination, but populations are growing older in Pennsylvania, West Virginia, Iowa, and North Dakota as well. In part this is because many younger people are moving to the Sun Belt states while older folks tend to remain close to home even in retirement, “aging in place.” Retirees are not evenly distributed across the country (Fig. 1.2). In 2003 Florida had the greatest percentage of residents over age 65 at 17 percent, but California had the largest population of older residents (about 4 million). The next oldest states include 5 6 Chapter One Negative net migration Positive net migration FIGURE 1.2 Moving to the Sun Belt: net migration of population over 65, 1995–2000. Retirees tend to relocate to a few parts of the United States, concentrating the need for services. (Source: U.S. Census Bureau, August 2005. Internal Migration of Older Population: 1995–2000. Used with permission of the University of North Carolina Institute on Aging.) Iowa, North Dakota, Pennsylvania, and West Virginia with about 15 percent each. The states with the fastest growing populations over age 65 were Nevada and Alaska. This distribution seems to demonstrate two general trends in retirement: one group that prefers to stay in their life-long communities and another that uses retirement to move to what they believe to be a more habitable climate or area. The number of older people is expected to double by 2025 in Montana, Idaho, Wyoming, Colorado, New Mexico, Arizona, Utah, Nevada, Washington, Oregon, the Carolinas, and Texas. Although many Americans are moving away from urban centers, immigrants tend to concentrate in “gateway” cities like Chicago, New York, and other former industrial cities. The number of immigrants to the United States promises to continue to be a factor in overall population growth. It is expected that by 2030 about 20 percent of the population of the United States will be aged 65 or older. About 78 million people are planning on retiring in the next 20 years. The oldest baby boomers enjoyed their 60th birthday in 2006. Boomer retirements will begin in earnest in 2010 and continue far beyond 20 years. As this is being written, the fastest growing age group in the United States is the 85+ group. The implications of this aging population are significant in many facets of our society and economy. This is true for planners and site designers as well. To appreciate the scope of the impacts and how we might prepare for and respond to them, some introductory discussion is appropriate. First, it may be necessary to reconsider what our view of aging is (Fig. 1.3). Key among our considerations is that the people who comprise this growing graying demographic are not easily captured by any one set of characteristics. For example, reports often relate how healthy the aging population is, and in fact the relative health of older people has continued to improve; but about 20 percent of them still report some form of disability or chronic illness. This will include more than 14 million people should the Sustainability and Site Design Percent of total population over 65 25–29.9 (0) 20–24.9 (0) 15–19.9 (3) 10–14.9 (42) 5– 9.9 (5) FIGURE 1.3 The graying of America: percent of total U.S. population over 65 in 2000. (Source: U.S. Census Bureau, 2005. State Interim Projections by Age and Sex: 2004–2030. Used with permission of the University of North Carolina Institute on Aging.) rate remain flat through 2030 (Fig. 1.4). It also means that any adult community is likely to be a microcosm of the various characteristics that make up the demographic. Design, therefore, should attempt to accommodate the community as a whole rather than any subset. It is true that as one ages mobility, balance, and perception are all subject to change, but the degree to which that happens to an individual is influenced by many different factors. What this means from a practical standpoint is that there is no average person on which to base a design. Percent of total population over 65 25–29.9 (6) 20–24.9 (19) 15–19.9 (23) 10–14.9 (2) 5–9.9 (0) FIGURE 1.4 The graying of America: percent of total U.S. population over 65 in 2030. (Source: U.S. Census Bureau, 2005. State Interim Projections by Age and Sex: 2004–2030. Used with permission of the University of North Carolina Institute on Aging.) 7 8 Chapter One The relative wealth of the retiring boomers has also received a good deal of interest. Much of this trend in retiree wealth is due to company-funded retirement, private savings, and Social Security—the often discussed “three-legged stool.” DeVaney and Chiremba (2005) found that the degree of preparation for retirement declined as one moved from early boomers (born 1946 to 1954) to the younger boomers (born 1955 to 1964) and on to Generations X and Y. Furthermore, the number of people participating in company retirement plans also has declined significantly, effectively removing one of the three legs from the retirement stool. Butrica and Uccello (2004) found that while early boomers are more likely to enjoy retirement at pretty much preretirement levels, younger or later boomers are less likely to be able to maintain their lifestyles. So it would appear that the earliest retirees from the boomer group are likely to be the best prepared for retirement, and as the retirement boom proceeds, the economic well-being of the group as a whole will decline to some degree. This reality may cause designers and planners to rethink how to accommodate the portion of older citizens without the resources to enjoy the active adult lifestyles and care so often portrayed as retirement in the United States. Implications With the anticipated increase in population, the need for water and energy conservation and planned growth becomes even more important and “smart growth” becomes critical. For communities in some parts of the country, development pressure will grow, and local government will have the opportunity to deal with growth-related issues including open space and public facilities before the crush. Community consideration of the standards to be used for that future growth should be undertaken as soon as possible: what is the community’s vision for its future? The growing older population nationwide represents opportunities for design firms but also represents significant challenges in some states where the majority of population growth is among the oldest people. The percentage of older people will continue to increase in the coming years, representing about 1 out of 5 people in the United States by 2050. It is expected that the baby boomers will enjoy a relatively healthy and active retirement that may represent a continuing demand for housing and recreation. The nature of these products should be expected to change, however. Some cultural observers anticipate a return to simpler values and even a growing spirituality in the culture as the boomers reach retirement. These trends may indicate a growing philosophical awareness of the boomers or may simply reflect lower retirement income. Communities that allow for real estate and school tax abatement for older taxpayers may experience shrinkage in local tax revenues at the same time that the population ages in place and demand for services for older citizens rises. This is especially true in those states in which the trend in the average age of the population increases as young people move away and older residents remain. Early indicators of two seemingly contradictory trends have been observed as retiring baby boomers move back into traditional large urban centers and into small towns. The reasons for these anticipated trends are equally diverse. Some retirees desire the cultural, civic, and social resources provided in large cities; others seek to escape the city for the perceived benefits of small rural towns. Their decisions may in part lie in the costs associated with these choices. Small town life may be less expensive than an active urban lifestyle. In the end these would appear to be quality of life choices by a very diverse demographic group. Both have important implications for communities and for site designers (Table 1.2). Sustainability and Site Design Population age 65 and older Total population State Alabama 2000 2025 % change 2000 2025 % change 4,451 5,224 17.4 582 1,069 83.7 Alaska 653 885 35.5 38 92 142.1 Arizona 4,798 6,412 33.6 635 1,368 115.4 Arkansas 2,631 3,065 16.5 377 731 93.9 California 32,521 49,285 51.5 3,387 6,424 89.7 Colorado 4,168 5,188 24.5 452 1,044 131.0 Connecticut 3,284 3,739 13.9 461 671 45.6 Delaware 768 861 12.1 97 92 (5.2) District of Columbia 523 655 25.2 69 92 33.3 Florida 15,233 20,710 36.0 2,755 5,453 97.9 Georgia 7,875 9,869 25.3 779 1,668 114.1 Hawaii 1,257 1,812 44.2 157 289 84.1 Idaho 1,347 1,739 29.1 157 374 138.2 Illinois 12,051 13,440 11.5 1,484 2,234 50.5 Indiana 6,045 6,215 2.8 763 1,260 65.1 Iowa 2,900 3,040 4.8 442 686 55.2 Kansas 2,668 3,108 16.5 359 605 68.5 Kentucky 3,995 4,314 8.0 509 917 80.2 Louisiana 4,425 5,133 16.0 523 945 18.2 Maine 1,259 1,423 13.0 172 304 76.7 Maryland 5,275 6,274 18.9 589 1,029 74.7 Massachusetts 6,199 6,902 11.3 843 1,252 48.5 Michigan 9,679 10,072 4.1 1,197 1,821 52.1 Minnesota 4,840 5,510 13.8 596 1,099 84.4 Mississippi 2,816 3,142 11.6 344 615 78.8 Missouri 5,540 6,250 12.8 755 1,258 66.6 Montana 950 1,121 18.0 128 274 114.1 1,705 1,930 13.2 239 405 69.5 Nebraska Nevada 1,871 2,312 23.6 219 486 121.9 New Hampshire 1,224 1,439 17.6 142 273 92.3 New Jersey 8,178 9,558 16.9 1,090 1,654 51.7 New Mexico 1,860 2,612 40.4 206 441 114.1 TABLE 1.2 Population Change from 2000 to 2025 9 10 Chapter One Population age 65 and older Total population State 2000 2025 New York 18,146 19,830 7,777 9,349 102.2 20.2 662 729 10.1 99 166 67.7 11,319 11,744 3.8 1,525 2,305 51.1 Oklahoma 3,373 4,057 20.3 472 888 88.1 Oregon 3,397 4,349 28.0 471 1,054 123.8 Pennsylvania 12,202 12,683 3.9 1,899 2,659 40.0 Rhode Island 998 1,141 14.3 148 214 44.6 3,858 4,645 20.4 478 963 101.5 777 866 11.5 110 188 70.9 5,657 6,665 17.8 707 1,355 91.7 Texas 20,119 27,183 35.1 2,101 4,364 107.7 Utah 2,207 2,883 30.6 202 495 145.0 617 678 9.9 73 138 89.0 Virginia 6,997 8,466 21.0 788 1,515 92.3 Washington 5,858 7,808 33.3 685 1,580 130.7 West Virginia 1,841 1,845 0.2 287 460 60.3 Wisconsin 5,326 5,867 10.2 705 1,200 70.2 525 694 32.2 62 145 133.9 North Carolina North Dakota Ohio South Carolina South Dakota Tennessee Vermont Wyoming % change 10.9 991 2000 2025 2,358 3,263 2,004 % change 38.4 Adapted from U.S. Census Bureau, 2000. TABLE 1.2 Population Change from 2000 to 2025 (Continued) Anticipated Effects of Global Climate Change Global climate change models anticipate a broad range of impacts. These impacts are believed to be under way already and will begin to manifest significant changes on the environment within the next 25 years and beyond. Many of these changes and impacts have direct implications for the development of land. North America has a largely urban population; 75 percent of the population lives in cities or the suburban fringe of metropolitan areas. Moreover, 75 percent of the population lives in what are termed coastal communities, that is, communities influenced or situated by large bodies of water. The United States is the world leader in the production of greenhouse gases, the human-cause of climate change. As governments around the world have recognized the trends indicating climate change is already occurring, international pressure has been increasing for the United States to change its behavior. Sustainability and Site Design Most climate change models are based on a doubling of carbon dioxide in the atmosphere. Carbon dioxide is a minor constituent in the atmosphere, representing only about 0.03 percent in the atmosphere. At the time the industrial revolution began, there were about 280 parts per million (ppm), down from 1600 ppm about 300 million years ago. Much of the carbon dioxide from earlier epochs has been sequestered in deposits of coal and oil, in peat bogs, and in tundra. In 2008 carbon dioxide was about 385 ppm, approximately a 35 percent increase from the preindustrial revolution level. It is estimated that carbon dioxide is increasing by about 2 percent annually and that a doubling of carbon dioxide over preindustrial revolution levels will occur in the second half of the twenty-first century. Current trends indicate the atmosphere will contain about 500 ppm by 2050 if current practices are not changed. It is anticipated that there will be important changes in world climate with such a rapid and dramatic increase in carbon dioxide levels. The models used to predict climate change trends are projections based on complex sets of factors. Different models give different results, but in general there is valid and significant agreement on global climate trends. There is a great deal of variability in the climate and weather of the United States and Canada. Projections of these models may have limited use on a local level, but it is important to note that observed changes in weather and climate are consistent with the predictions of global climate change. Uncertainty exists in the models partly because of the limitations of data and science’s ability to model something as complex as world climate, but also because it is unknown how people and governments will react to the information. If governments and business respond and reduce the emissions or alternatively increase the sequestration of carbon, for example, the impact and degree of change may be less. All of the models presume a doubling of carbon dioxide by 2100; more recent data from the International Panel on Climate Change (2007) indicates the doubling may occur faster than originally expected. Global average temperature increased 1°F in the twentieth century, but most of the increase occurred in the past 30 years, indicating that the rate of warming is increasing (Table 1.3). The 2007 report from the Intergovernmental Panel on Climate Change (IPCC) was significant for several reasons. First, it acknowledged that the evidence for humancaused global climate change was “unequivocal.” This was the strongest language used in any of the four IPCC reports. Second, the fourth assessment report was the first to rely primarily on observed changes in global climate rather than model-based predictions. Even the best-case scenarios of climate change indicate significant effects, but the effects are not expected to be the same everywhere. The area of greatest temperature change is expected to be in a zone from northwestern Canada, across southern Canada and the northern United States, to southeastern Canada and the northeastern United States. Average temperatures are rising significantly because the lows are not as low as they used to be. Average temperatures are expected to increase as much as 4°F over the next 100 years. This increase in temperature will decrease the area and length of time of annual snow cover and should result in earlier spring melts. The risk of rain-on-snow storms will also increase, and with it the risk of associated floods. Further, the reductions in snowpack have a direct influence on water supply. For most of the western United States, snowpack is the largest reservoir of water storage and directly affects stream flow. The world’s oceans are warming as well. The temperature of the sea is expected to rise and influence the weather. Thermal expansion of the ocean and increases in runoff 11 12 Temperature change (°F) Precipitation change (%) State Spring Summer Fall Winter Spring Summer Fall Winter Alabama 3 2 4 2 10 15 15 No change Alaska 5 5 5 10 15 10 Slight change Slight change Arizona 3–4 5 3–4 5 20 Slight change 30 60 Arkansas 3 2 3 2 15 25 15 No change California <5 5 <5 5 20–30 No change 20–30 >20–30 Colorado 3–4 5–6 3–4 5–6 10 Little change 10 20–70 Connecticut 4 4 4 4 <10–20 <10–20 10–20 >10–20 Delaware 3 4 4 4 <15–40 15–40 <15–40 >15–40 Florida 3–4 3–4 3–4 3–4 Little change Little change Little change Little change Georgia 3 2 4 3 10 15–40 15–40 10 Hawaii 3 3 3 3 Uncertain of changes Uncertain of changes Uncertain of changes Uncertain of changes Idaho 4 5 4 5 10 Little change 1 20 Illinois 3 2 4 3 10 25–70 15–50 10 Indiana 3 2 4 3 10 10–50 20 10 Iowa 3 2 4 4 10 20 15 10 Kansas 2 3 4 4 15 15 15 Little change Kentucky 3 <3 >3 3 20 30 20 <10 Louisiana 3 3 >3 <3 Little change 10 10 Little change Maine <4 >4 >4 <4 Little change 10 10 30 Maryland 3 4 4 4 <20 20 <20 20 Massachusetts 4 5 5 4 10 10 15 20–60 Michigan 4 4 4 4 5–15 20 5–15 5–15 Minnesota 4 <4 4 4 Little change 15 15 15 Mississippi 3 2 4 2 10 15 15 Little change Missouri 3 2 3 3 15 20–60 15 Little change Montana 4 4 5 5 10 10 10 15–40 Nebraska 3 3 4 4 10 10 10 15 Nevada 3–4 5–6 3–4 5–6 15 (10) 30 40 New Hampshire 4 5 5 5 Little change 10 10 25–60 New Jersey 4 >4 >4 4 <10–20 10–20 10–20 >10–20 New Mexico 3 5 4 5 15 Slight decrease Slight increase 30 New York 4 >4 >4 4 <10–20 10–20 10–20 >10–20 North Carolina 3 3 3 3 15 >15 >15 15 North Dakota 4 3 4 4 5 10 20 25 Ohio 3 3 4 3 5–25 25 20 5–25 Oklahoma 2 3 3 4 20 20 Slight increase Little change Oregon 4 5 4 5 Slight increase Slight decrease 15 15 Pennsylvania <4 >4 >4 <4 10 20 50 20 Rhode Island 4 5 5 4 10 10 15 25 South Carolina 3 3 3 3 15 >15 >15 <15 South Dakota 3 3 4 4 10 10 10 20 Tennessee 2–3 <2–3 2–3 2–3 20 30 20 Slight increase TABLE 1.3 Anticipated Temperature and Precipitation Impacts of Climate Change (Continued) 13 14 Temperature change (°F) Fall Precipitation change (%) State Spring Summer Winter Spring Summer Texas 3 4 4 4 10 10 10 (5–30) Utah 3–4 5–6 3–4 5–6 10 (10) 30 40 Vermont 4 4 5 5 Little change 10 10 30 Virginia 3 3 4 3 20 20 20 20 Washington 4 5 4 5 Little change Little change Little change 10 West Virginia 3 3 4 3 20 20 20 >20 Wisconsin 4 <4 4 4 Little change 15–20 15–20 15–30 Wyoming 4 5 4 6 10 Slight decrease 10 30 Adapted from the U.S. EPA. TABLE 1.3 Anticipated Temperature and Precipitation Impacts of Climate Change (Continued) Fall Winter Sustainability and Site Design from glaciers and ice fields are expected to continue and result in rising ocean levels. In places such as Texas and Louisiana, rising seas may be made worse by concurrent land subsidence. The world’s oceans are expected to rise by 20 inches or more by 2100. Such an increase has significant implications for coastal communities. An increase in the intensity, though not the frequency, of hurricanes has been observed as the world’s oceans have warmed. Perhaps a more troubling issue is the acidification of the world’s oceans. In point of fact the world’s oceans are slightly alkaline, but there has been a reduction in the alkalinity of the seas as carbon dioxide levels in the atmosphere have increased. The seas absorb carbon dioxide from the atmosphere and in so doing help to mitigate the accumulation of the gas in the atmosphere. As the amount of carbon dioxide dissolved in seawater increases, so do the hydrogen ions and hence the pH is lowered. As the oceans become more acid, it is expected that there will be a negative impact on calcifiers—organisms that use calcium carbonate to construct shells or skeletons—because calcium carbonate readily dissolves in acidic conditions. These organisms represent an important part of the marine food chain. They include corals and shellfish and are widely distributed throughout the seas. The science on this point is not conclusive; some calcifiers actually became slightly more robust under some circumstances of mild acidification. As sea levels continue to rise, increases in shore and beach erosion should be anticipated along coastlines. Barrier island communities may experience significant losses. Local and state governments will be required to devise strategies for affected communities that may require significant public expense. Insurance for coastal properties can be expected to rise significantly. Reinsurance companies have reported catastrophic insurance losses associated with weather, increasing to $300 billion worldwide through 2007. Several major insurance companies announced in 2007 that they would no longer write new flood insurance policies for properties within 2500 feet of the mean high tide line in states from Delaware to Mississippi, including waterfront along the Chesapeake Bay. This makes publicly funded insurance the only source of support for affected landowners. Beach replenishment will become an increasingly expensive and perhaps more futile effort (Table 1.4). Barrier islands should be expected to shift landward in response to deepening oceans. Necessary mitigation methods such as the construction or improvement of existing sea walls or bulkheads or installation of revetments or levees on bayside beaches would add costs to the beach replenishment efforts. It is important to note that some of these costs are already being paid. Sea level rise has significant implications for water supply as well. Saltwater encroachment may become a larger problem as coastline communities continue to grow and groundwater use increases. It is expected that as much as 50 percent of the coastal wetlands will be inundated. Louisiana is currently losing 35 square miles of wetland each year due to saltwater intrusion. Coastal wetlands generally can adapt to nominal sea level rise and fall. As vegetation experiences seasonal diebacks, decaying detritus adds to the wetland soil and allows the wetland to “lift” in response to moderately rising seas. This capacity is believed to be limited to about a 2 millimeter (mm) per year lift. Sea level rise along much of the eastern coast of the United States has exceeded this rate, and the rate of sea level rise appears to be increasing, in effect drowning the wetlands. Rising sea levels will also complicate floods on tidal influenced rivers and streams. Increased storm surges may back up streams and change flood plain characteristics. It has been calculated that a sea level rise of 40 inches (1 meter) would result in a flood 15 16 Chapter One State Cumulative costs of shoreline protection (millions of dollars) Alabama 60–200 California 174–3,500 Connecticut 500–3,000 Delaware 34–147 Florida 1,700–8,800 Georgia 154–1,800 Hawaii 340–6,000 Louisiana 2,600–6,800 Maine 200–900 Maryland 35–200 Massachusetts 490–2,600 Mississippi 70–140 New Hampshire 39–104 New Jersey (Long Beach Island only) 100–500 bulkheads and sea walls New York (Manhattan Island only) 30–140 bulkheads and sea walls North Carolina 660–3,600 Oregon 60–920 Rhode Island 90–150 South Carolina 1,200–9,400 Texas 4,200–12,800 Virginia 200–1,200 Washington 143–2,300 Compiled from U.S. EPA information. TABLE 1.4 Estimated Cost of Sand Replenishment for a 20-inch Rise in Sea Level with a frequency of 15 years actually inundating the same area a 100-year flood did previously (Table 1.5). FEMA estimated that rises of 12 and 36 inches would increase the area affected by a 100-year flood from 19,500 square miles to 23,000 and 27,000 square miles, respectively. Damage resulting from these floods would be expected to rise 36 to 58 percent for a 12-inch increase and from 102 to 200 percent for a 36-inch increase. Precipitation patterns along the Gulf Coast, central and northern plains, and parts of the midwestern and northeastern United States may increase as much as 10 to 20 percent annually. More frequent storms of higher intensity may change the distribution of precipitation and result in less infiltration and a greater amount of runoff. The result would be falling groundwater tables and less water in streams and lakes. The shortened Sustainability and Site Design State Temperature change +/(-) (°F) Precipitationa (% change) Sea level changeb Anticipated sea level change (inches) (2000–2100) 20 Alabama (Tuscaloosa) (0.1) 20 9 Alaska (Anchorage) 3.9 10 – Arizona (Tucson) 10 c 3.6 20 – Arkansas (Fayetteville) 0.4 20 – – California (Fresno) 1.4 20 3–8 13–19 Colorado (Fort Collins) 4.1 20 – – Connecticut (Storrs) 3.4 20 8 22 Delaware (Dover) 1.7 10 12 23 2 d 7–9 18–20 13 25 6–14 17–25 Florida (Ocala) Georgia (Albany) (0.8) 10 Hawaii (Honolulu) 4.4 20 e Idaho (Boise) <1 20 – – Illinois (Decatur) (0.2) 20 – – Indiana (Bloomington) 1.8 10 – – Iowa (Des Moines) (0.02) 20 – – Kansas (Manhattan) 1.3 <20 – – 10 – – Kentucky (Frankfort) Louisiana (New Orleans) (1.4) No change 5–20 Maine (Lewiston) 3.4 20 3.9 14 Maryland (College Park) 2.4 10 7 19 Massachusetts (Amherst) 2 20 11 22 Michigan (Ann Arbor) 1.1 20 – – Minnesota (Minneapolis) 1 20 – – Mississippi (Jackson) 2.1 20 5 15 Missouri (Jefferson City) (0.5) 10 – – Montana (Helena) 1.3 (20) – – f Nebraska (Lincoln) (0.2) 10 – – Nevada (Elko) 0.6 20 – – New Hampshire (Hanover) 2 20 7 18 New Jersey (New Brunswick) 1.8 5–10 15 27 TABLE 1.5 Climate and Sea Level Change 17 18 Chapter One State Temperature change +/(-) (°F) Precipitationa (% change) Sea level changeb Anticipated sea level change (inches) (2000–2100) New Mexico (Albuquerque) (0.8) 20 – – New York (Albany) >1 20 10 22 North Carolina (Chapel Hill) 1.2 5 2 12 North Dakota (Bismarck) 1.3 (10)g – – Ohio (Columbus) 0.3 10h – – Oklahoma (Stillwater) 0.6 20 – – i Oregon (Corvallis) 2.5 20 4 6 Pennsylvania (Harrisburg) 1.2 20 – – Rhode Island (Providence) 3.3 20 2 12.4 South Carolina (Columbia) 1.3 20 9 19 South Dakota (Pierre) 1.6 20 – – Tennessee (Nashville) 1 10 – – Texas (San Antonio) 0.5 (20) 25 38 Utah (Logan) 1.4 20 – – Vermont (Burlington) 0.4 5 – – j Virginia (Richmond) 0.2 10 12 23.3 Washington (Ellensburg) 1 20 8 19 101 10 – – (20) – – West Virginia (Charleston) Wyoming (Laramie) 1.5 a Change may not address all parts of a given state Rate of change historically c Some parts of Arizona have experienced a 20 percent decline in precipitation d Precipitation has decreased in the south and keys and increased in the north and panhandle e Precipitation has decreased as much as 10 percent in some parts of Idaho f Except in western Nebraska, where precipitation has fallen by 20 percent g Except southeastern part of South Dakota, where precipitation has risen slightly h Precipitation has decreased in southern Ohio i Except leeward side of Cascade Mountains, where precipitation has decreased by 20 percent j Other parts of Virginia have shown a decrease in temperature Compiled from U.S. EPA information and James G. Titus and Vijay Narayanan. 1995. “The Probability of Sea Level Rise.” EPA 230-R98-008. b TABLE 1.5 Climate and Sea Level Change (Continued) Sustainability and Site Design snow season may result in less snowpack in western states and earlier runoff. Reservoirs built to collect runoff for use throughout the year may begin to have a longer service period and experience shortages earlier in more frequent dry years. Earlier runoff may result in lower stream and river flows later in the summer as well. Reduced flows could affect hydroelectric production in some places. More frequent and intense rains will result in increases in storm runoff, erosion, and slope instability. The increase in runoff may require a rethinking of the maximum probable storm event in many places. It may require retrofitting exiting storm water collection and control devices to retain more water and encourage infiltration. Paradoxically, along with an increase in precipitation there is expected to be an increase in the number and severity of droughts. Increased temperatures will result in an increase in evaporation and a loss of soil moisture. The loss of soil moisture and the increased runoff associated with more intense storm events may result not only in lower streams and rivers but also in warmer streams and rivers. Cold water fisheries may become endangered in the southern-most ranges. Falling levels in the Great Lakes have already been observed, and it is possible that falling levels could limit commercial traffic in the St. Lawrence River at certain times during dry years. This may be offset, however, by a longer ice-free season in the Great Lakes. The causes of the declining levels in the lakes are still being evaluated, but several causes are thought to be at work: reduced snowfall and rain in the contributing watersheds and the combined effects of gravel mining and widening and dredging the St. Clair River to facilitate commercial traffic. In essence the latter activities may have resulted in an unintended draining of the upper Great Lakes. An increase in carbon dioxide should result in more robust plant growth. Some have observed that this is the “upside” to global climate change and will increase food and fiber production. Other studies have found that as carbon dioxide levels increase, some plants reduce their rate of photosynthesis. Still others observe that the increased production of plant mass results in an increase in plant litter and thereby changes the carbon-nitrogen ratio in the soil, in effect reducing the amount of nitrogen available for plants. The increase in leaf area will also increase the amount of transpiration, contributing to the drying of soils. Implications The implications of climate change may be significant. It is possible that most of the United States will experience an increase in the frequency of precipitation, both in terms of the amount of rainfall and its distribution. Increased erosion and perhaps slope destabilization in some places can be expected with such an increase. Coastal communities may experience an increase in flooding and beach erosion. Flood prone areas may increase in size as the sea levels rise. Public health officials and communities may become more sensitive to areas of standing water as subtropical and tropical diseases expand their range. Design strategies in affected coastal communities may provide significant opportunities for innovation and problem solving. Site planners and designers will have to respond to these trends in both retrofitting existing facilities and designing new projects. While infiltration will continue to be an important element of site planning, perhaps the wet pond will be less desirable with the spread of West Nile Virus or malaria. Clearly site planners will have to account for the life cycle and habitat preferences of the mosquitoes that transmit such diseases in their design and planning. 19 Chapter One Anticipated warming in most places will result in increasing cooling costs for buildings and homeowners. Properly locating a building on the site and planning plantings to lower energy costs will become even more important elements of the site plan. As temperatures increase, plants growing at their southern range may be subject to significant heat and increasing drought-related stresses. Some places may see a shift in “native species,” particularly those living at the margins of their tolerance. Land Use Since World War II the growth of suburban development has been the most important and possibly the most environmentally damaging trend. At the beginning of the twentyfirst century more people live in the suburbs than in the former urban centers. There has been a growing awareness that suburbs as they have evolved are unsustainable, but that awareness has done little to slow growth or change consumer preference. There is a general acknowledgment that cities offer a greater cultural experience, but populations have not started to return in significant numbers. People have voted with their feet and their checkbooks and shown their preference for suburban living over city living. Builders respond to market demand; they do not, for the most part, create it. Changing such a trend would require changes to public policy that are politically difficult, if not impossible, to achieve. Local ordinances tend to favor low-density development and highways rather than parks and higher-density development. It is difficult for planners and designers to influence this trend on a site-by-site basis, but planners and designers can address the impacts of suburban development through design. Figure 1.5 illustrates the effect of urban or suburban expansion without population growth. As sprawl continues, we consume more and more land per person, more infrastructure per person, and have a greater environmental impact as well. 60 Percent growth 20 51.5% 50 40 30 22.6% 20 10 0 Per capita land consumption growth Rate of sprawl FIGURE 1.5 Growth in per capita land consumption compared to overall sprawl rate. The overall rate of sprawl was more than double the growth of per capita land consumption (1970–1990) in the average of the one hundred largest U.S. urbanized areas. (Source: U.S. Bureau of Census reports on Urbanized Areas, 1970 to 1990.) Sustainability and Site Design FIGURE 1.6 A traditional street and neighborhood. In surveys people express a preference for neighborhoods with traditional characteristics such as narrower streets and shopping and recreation within walking distance. Paradoxically, many people living in the suburbs seem to prefer what might be considered urban values and character. The National Association of Home Builders (NAHB) study (Currens, 2004) found that those surveyed would prefer to live within walking distance of schools, shops, and community facilities (Fig. 1.6). The study also found that in spite of the standard practices of most zoning ordinances people would rather live in a place with narrower streets and more public open space (Fig. 1.7). During a time when American families have become smaller by nearly half, new houses have ballooned to more than twice their previous size. As the population has become older, however, there is an increasing interest in smaller homes. In some metropolitan areas most of the homes built and purchased are townhouses and condominiums. Part of this popularity may be due to the cost of housing in urban areas, but many of these units are higher-end dwellings located near shopping or social and cultural features of the city. The popularity of the southwestern United States has its own significant challenges (Fig. 1.8). The influx of people from more humid parts of the country has brought with it an expectation of life and an aesthetic that often is simply out of place in the desert. The native people of these dry places have long ago found ways to live that recognized the character of their region. Our culture is faced with learning and acting on the lessons already known by so many, but our footprint is so much larger and deeper. It remains to be seen whether we can find ways to live sustainably and successfully in the desert. 21 22 Chapter One FIGURE 1.7 A contemporary urban neighborhood. FIGURE 1.8 Homes should reflect their region and environmental characteristics as does this development in the southwest. Sustainability and Site Design The southeastern United States is also growing and facing problems with water supply as well as significant declines in other environmental indicators such as air quality, biodiversity, and human health. This move to the south and the suburbs leaves many cities with declining populations and tax bases but faced with underutilized infrastructure and the remains of an industrial past that lasted only 50 years in many places. Brownfield opportunities in cities in the last few years have provided designers with unique challenges. This requires a different mind-set and more than a few new skills. Site designers must confront the impacts of industrial contamination; we can no longer assume that a site is healthy. Professional boundaries often blur within the context of these projects, and design professionals may find themselves working on more diverse project teams as they search for innovative solutions to complex problems. Energy It is widely believed that the world is facing a time of increasing energy supply issues. The modern global economy and the U.S. economy have grown in part on the foundation of relatively inexpensive energy primarily provide by various forms of fossil fuels. We have leveraged the tremendous concentration of energy found in these fuels to create ever-more productive processes and systems, which in turn enabled the production of lower cost products, faster, cheaper transportation, and new materials. Today the United States is the largest consumer of oil in the world but produces less than 50 percent of its consumption. In 1994 the United States consumed 17.7 million barrels of oil each day (mb/day). By 2007 that amount increased 17 percent to 20.7 mb/day. China’s consumption in that time rose 140 percent from 3.16 to 7.58 mb/day. Other Asian nations also increased oil consumption 60 percent in this time as they moved toward ever-more modern economies. Total world oil production of OPEC and nonOPEC producers in 1994 was 75.76 mb/day. By 2007 this had risen to 85.36 mb/day, an increase of 12.6 percent. Total reported global demand for oil in 2007 was 85.36 percent. Even a cursory review of global oil production trends suggests the time of oil surpluses has ended. Ever-growing demand will result in higher energy costs and tighter supply, and energy conservation and efficiency will become more important considerations in development of all forms. Buildings represent a significant source of energy demand associated with land development, and site designers will be called upon to participate more broadly and to contribute to the new principles that are already being used in the marketplace. Water Much of the United States enjoys an adequate supply of water although the amount of precipitation and surface water availability declines as we move from east to west (see Table 1.5). Local variability is significant, ranging from 1 inch per year in the southwest to more than 60 inches per year in the southeast. Such variability suggests the difficulty in finding wide-ranging solutions. Although water is a renewable resource, supply issues do exist and promise to become more significant as time passes. Annual natural variations in precipitation can result in local and regional water management issues and conflicts. It is unclear to what degree these natural variations will be exacerbated at the local level by climate change, but most climatologists agree that extreme weather events and patterns will become more frequent and more persistent. This suggests that 23 24 Chapter One periods of wet or dry weather patterns may last longer and be more intense. Water policy tends to be a regional concern, but clearly there is a role for the site planner in water management issues. Water supply is an issue in many localities and efforts at water conservation in communities in the southwestern and western states are notable. In recent years concerns with supply have become greater in the eastern states as well as populations grow and demand rises. Water use on a per capita basis peaked in 1975, but population has increased dramatically since then so total water use continues to rise, albeit more slowly. Planners generally use a figure of 100 gallons per day per person for planning based on historic records, but this figure includes only domestic use by individuals. Most water is used for other purposes including irrigation, power generation, and commercial use. In general as a community grows, water demand increases several times faster than the domestic use alone would indicate. In 1990 water use in the United States was about 1300 gallons per person per day. About 70 percent of this is withdrawn but eventually returned to the source; the remaining water is “consumed.” There are limited practical opportunities to develop or expand new sources of potable water. These include recycling water, desalinization, expanding the use of existing sources, and conservation. Recycling water through gray water systems and other approaches have been successful in many places, but most often they are used in limited applications. The cost of recycling water on a community basis is at least several times more expensive than developing new public or community water. Desalinization is energy intensive, and though technologies in recent decades have reduced the cost of desalinized water, it remains an expensive source of water. As energy costs continue to rise, the cost of desalinized water also may rise unless new advances can keep pace. Desalinization may be affordable in areas where brackish water is to be treated; however, affordability is relative to community resources. Expanding withdrawal from existing sources may be more affordable, but as pressure on these resources increases so does their vulnerability to the effects of drought. Conservation is the most affordable and practical approach to the water issues facing communities. Designers have an important role to play in water conservation. It is recommended that low-impact design be utilized to reduce the water demand of a site and to maximize the amount of runoff retained on the site. Employing vegetated swales, constructing rain gardens, using permeable paving, and reducing lawn areas are important elements of water conservation in the site design. The use of gray water and recycled water for landscape purposes, selecting native plants, and collecting and storing runoff on site also contribute to reducing the impact of site development. Working with architects to install green roofs and designing on-site sewage collection systems can also be part of the conservation strategy. Site design and planning today have started to move beyond the practices and paradigm of the past. Designers working in the contemporary marketplace are or soon will be expected to bring solutions to the problems discussed in this chapter for their clients. While many of the professionals’ familiar skills will still be needed and valuable, they will undoubtedly be informed by the emerging considerations and concerns of the communities and clients they serve.