The structure and design of future urban development can have significant adverse effects on air pollutant emissions as well as other environmental factors. When considering the future impact of ...growth on mobile source emissions, we generally model the increase in vehicle kilometers traveled (VKT) as a function of population growth. However, diverse and poorly planned urban development (i.e., urban sprawl) can force higher rates of motor vehicle use and in return increase levels of pollutant emissions than alternative land-use scenarios. The objective of this study is to develop and implement an air quality assessment tool that takes into account the influence of alternative growth and development scenarios on air quality.
The use of scenario-based techniques in land use planning has been around since the late 1940s and been tested in many different applications to aid in decision-making. In this study, we introduce the development of an advanced interactive scenario-based land use and atmospheric chemistry modeling system coupled with a GIS (Geographical Information System) framework. The modeling system is designed to be modular and includes land use/land cover information, transportation, meteorological, emissions, and photochemical modeling components. The methods and modularity of the developed system allow its application to both broad areas and applications.
To investigate the impact of possible land use change and urbanization, we evaluated a set of alternative future patterns of land use developed for a study area in Southwest California. Four land use and two population variants (increases of 500k and 1M) were considered. Overall, a Regional Low-Density Future was seen to have the highest pollutant emissions, largest increase in VKT, and the greatest impact on air quality. On the other hand, a Three-Centers Future appeared to be the most beneficial alternative future land-use scenario in terms of air quality. For all cases, the increase in population was the main factor leading to the change on predicted pollutant levels.
While landscape planning can help society meet its goals, the ultimate success of today's decisions will be determined, in part, by factors that are difficult to control or to forecast. This study ...explored how uncertainties related to urban growth in the biologically rich, but rapidly developing area between Los Angeles and San Diego might influence the natural systems of the region and, in turn, contribute to land stewardship pressures. The work was focused through a set of ecological management concerns of the region's military installations. As urbanization removes or degrades habitat, these large and largely un-built properties are increasingly important for the maintenance of regional biodiversity. Looking forward, stakeholders are asking how might growth affect the “rules of engagement” that allow the military to fulfill its mission and native species to continue to exist in the area? A set of scenarios describe possible interactions of macro-scale forces of change and commensurate regional responses; associated analyses locate and quantify the consequences. Each scenario presents unique potential challenges and the set captures a range of alternative management contexts. In examining what the future
might become rather than what it
should become, this approach provides a geographic vulnerability analysis that can help stakeholders assess the long-term success of pending local environmental plans and, thereby, make decisions that are more robust to uncertainties related to exogenous forces of change.
Studies of future management and policy options based on different assumptions provide a mechanism to examine possible outcomes and especially their likely benefits and consequences. The San Pedro ...River in Arizona and Sonora, Mexico is an area that has undergone rapid changes in land use and cover, and subsequently is facing keen environmental crises related to water resources. It is the location of a number of studies that have dealt with change analysis, watershed condition, and most recently, alternative futures analysis. The previous work has dealt primarily with resources of habitat, visual quality, and groundwater related to urban development patterns and preferences. In the present study, previously defined future scenarios, in the form of land-use/land-cover grids, were examined relative to their impact on surface-water conditions (e.g., surface runoff and sediment yield). These hydrological outputs were estimated for the baseline year of 2000 and predicted twenty years in the future as a demonstration of how new geographic information system-based hydrologic modeling tools can be used to evaluate the spatial impacts of urban growth patterns on surface-water hydrology.
