Spatial Technologies-GIS in Resource Management30 Jun, 2006 By: James L. Sipes
Guardians of the environment use spatial technologies to monitor land, water and air
The conservation and preservation of natural resources is a daunting task because the resource areas include tens or hundreds of thousands of acres, and the issues that need to be addressed are very complex. Resource managers need to understand the effects development will have on the lands they oversee. These effects may be obvious, such as urban sprawl, or more subtle, such as carbon dioxide from traffic traveling through or near an area. GIS is an ideal tool for natural resource management because the profession focuses primarily on the opportunities and constraints inherent in a landscape.
Uses of GIS in resource management vary from simple map analysis, such as calculating area and measuring distances, to more sophisticated modeling procedures that seek to simulate natural processes.
GIS is the perfect tool for resource managers because most data they use is geospatial in nature. With GIS, resource managers can ask critical what-if questions. How can we minimize the effect of air pollution on sensitive ecological areas? Where should we limit development to minimize surface runoff? Where best can we harvest timber to minimize environmental impacts? What are the migration patterns for particular species?
Resources to get you started
Resource managers use GIS for applications such as groundwater assessment, soil erosion potential evaluation, water resource assessment, watershed planning, irrigation water management, vegetation mapping, land-use planning, evapotranspiration assessment, ecosystem analysis, conservation planning, risk assessment, costal zone management and hazard mapping, When it comes to water-oriented resources, GIS has been used to map coral reef habitat, movements of glaciers, speed of tidal currents, spread of oil spills, impacts of typhoons, changes in sea temperature, changes in shoreline, changes in oyster bed density, growth of sea grass and plankton and the location of red tides.
Resource managers with the U.S. Forest Service are concerned with how to achieve an economically viable level of timber harvesting while still maintaining a balanced and healthy environment. Most federal land-management agencies, including the Forest Service, have used some form of GIS since the early 1980s. In the years before GIS, these agencies relied on a combination of institutional memory and educated guesses to determine when, where and how much timber to harvest.
The Wisconsin DNR (Department of Natural Resources) uses GIS to help provide access to information about the state's land, water and air resources. The data sets used by DNR were developed to be applicable for a variety of purposes. Many of these data sets are managed in a central data repository, but some are controlled by individual departments within DNR. Collectively, these data sets are used as the foundation for spatial analysis and management that supports policy decisions made by DNR.
GIS also can be used for participatory mapping that allows a community to get involved with land-use decisions. This ability is important because many times resource managers are trying to meet human needs while also protecting natural resources. In Finland, for example, public participation tools such as surveys and decision analysis are combined with GIS applications to influence forestry within the country. The technology is not as effective, however, at resolving value-based conflicts.
The AGNPS (Agricultural Nonpoint Source) pollution model was developed by the U.S. Department of Agriculture to help understand the effect of agricultural land on water quality. The program uses variables such as soil type, land cover, management practices, slopes and surrounding land uses to help determine this impact. Environmental modeling is possible because GIS applications can integrate the wide array of data needed to make such simulations reliable. These types of modeling techniques include simulating the way a fire spreads, predicting how surface runoff occurs, forecasting potential changes in vegetative patterns and anticipating urban sprawl tied to population growth and land-use planning. It's worth noting, though, that a model is only as good as the accuracy of the methodology used to define a particular process and the quality of the data input into the model.
The CRMS (Center for Remote Sensing and Mapping Science) at the University of Georgia is conducting several GIS projects involving natural resources. The Center's work focuses on interdisciplinary research projects that include ecology, forestry, geography, geology and hydrology. CRMS has been actively studying natural resource management, soil erosion, water runoff and global mapping. To study soil erosion, the center worked with the U.S. Department of Agriculture to develop GIS methods for measuring erosion, which is linked closely to the flow of fertilizers and pesticides into waterways. CRMS also worked with the Georgia Department of Natural Resources to develop models that would simulate how sediments move through a watershed.
At the Sapelo Island National Estuarine Research Reserve, CRMS used GIS to create detailed maps of the land use and vegetation on the island and surrounding marshes. The project helps preserve some of the last unaltered salt marshes on the Atlantic coast. Researchers used aerial photographs dating back to 1953 to see how marshes changed over the years.
Historic wildlife habitat areas are dependent primarily on topography, vegetative cover, access to food source and proximity to water. This type of geospatial data can be readily modeled in GIS for any individual species. When rebuilding U.S. Highway 93 in western Montana was discussed, one of the key issues was the effect on wildlife. This part of the state has an abundance of wildlife. The highway traverses the Flathead Indian Reservation, and wildlife is part of the local tribes' cultural heritage. One major decision made by the design team and supported by federal, state, and tribal governments was to realign the existing highway to avoid wildlife habitat, protect culturally significant areas, and minimize impact to the land.
Getting wildlife across U.S. 93 was critical, because if the highway posed a barrier to wildlife migration, it would threaten the health of the animals. An estimated one million vertebrates—amphibians, reptiles, birds and mammals—are killed on U.S. roads and highways each day. By looking at wildlife habitat areas and roadkill data, and tracking information and sightings, the design team members identified the historic migration patterns that were disrupted by the construction of Highway 93. Most of this information had already been put in GIS format by tribal resource managers. This data was the foundation for making many of the decisions about aligning the road.
The final design incorporated more than 40 wildlife crossings, more than any other highway in North America. These crossings are not just signs to slow traffic, but implement multifaceted strategies to funnel migrating wildlife to safe crossings under and over the road bed. They range from culverts for fish to bridges and a major underpass for larger animals. Where necessary, specially designed fencing will be tucked into the surrounding landscape to control animal movement and direct it toward crossings.
Imagery and GPS
The availability of aerial photographs and satellite imagery has improved efforts to manage natural resources. "Sixty percent of our time in the past was used to create ortho-imagery for our projects," says Marguerite Madden, director of CRMS. Because aerial and satellite imagery is so readily available, resource managers have more time to focus on the issues.
LIDAR (light detection and ranging) provides a level of detail that enables users to see detail not only on the ground plain but also in tree canopies and understory plants. LIDAR's biggest limitation is that it is expensive, but costs will drop over time, as with all technologies. Madden believes that everyone will have access to LIDAR data in 10 years or so.
A potential problem with new technologies such as LIDAR, though, is that they produce an amazing amount of data, and researchers don't yet have a way to use it effectively. One important concept is the idea of generalization, which involves using filtering techniques to make a data set more manageable by deleting redundant data. For example, if you have five or six data points that give you basically the same information, generalization routines evaluate which point is most accurate and then delete the other five points. Generalization not only reduces the amount of data you have to work with, it also makes it easier to work with the data. This is particularly valuable when accessing data using handheld units with very small viewing screens.
GPS had a tremendous impact on how resource managers do their job, because they were able to accurately locate natural features on-site for the first time. Botanists use GPS to locate endangered plant species, wetland geologists use the technology to delineate wetlands and wildlife biologists can clearly mark movement trails and habitat areas.
"The biggest benefit of GPS technology is that it allows us to put resource management tasks in a spatial context, so we can look at distribution patterns and how the landscape changes over time," says Madden. This capability helps resource managers make better decisions about protecting resources.
As in every profession, resource managers are in a constant struggle to do more with less. Budgets are getting smaller, while at the same time the issues they deal with are more complicated than ever. GIS is a way to enable resource managers to do their job better and more efficiently, as long as they can find a way to balance the budget at the same time. Trends indicate that this reliance on GIS is likely to continue.
"The technology is becoming much more assessable to younger and younger scientists," says Madden. Previously, bottlenecks often occurred because only one or two people in an organization knew GIS. Now, notes Madden, you don't have to train for years to use the technology: "The technology is more transparent and more accessible than every before. Programs like Google Earth are putting geospatial technology in the hands of the public."
A lot of work done in resource management has depended on automated techniques that seek to obtain meaning from aerial and satellite imagery, but one major trend is a move toward greater reliance on human perspective. "We realized the significant limitations of automated techniques," says Madden. "The human brain can interpret results much better than any computer program."
For those interested the use of geospatial technologies in resource management, ASPRS (American Society of Photogrammetry and Remote Sensing) is a good place to start. Madden is the president-elect of ASPRS, which has been in existence since 1934. Its more than 7,000 members come from various organizations representing government, academia and industry. Its mission is to promote the responsible applications of photogrammetry, remote sensing, GIS and supporting technologies.
James L. Sipes is a senior associate with EDAW in Atlanta, Georgia, and the founding principal of Sand County Studios in Seattle, Washington. Reach him at email@example.com.