One of the chief advantages that GIS has always had as an instructional and research tool is its ability to help people understand interconnections between issues, phenomena, and data. A set of interconnections that are important to people’s everyday lives around the planet is those between the existence of surface drinking water sources, watersheds, development, the extent of forests, and threats to forests from insects, disease, and wildfires.
Forests are a critical part in keeping water clean and pollution-free. Forest are “living filters” that provide clean water by intercepting and absorbing sediment, excess nutrients, and pollutants. Trees also help store water and release it slowly over time, enhancing water quantity. Most of the world’s population lives downstream from forested watersheds, and 40% of the world’s 100 largest cities rely on runoff from protected areas.
The US Forest Service (USFS) project “Forests to Faucets” provides information that can identify areas of interest for protecting surface drinking water quality. The spatial datasets produced by the project can be incorporated into broad-scale planning and decision support tools, and sets the groundwork for identifying watersheds where a payment for watershed services (PWS) scheme may be an option for financing forest conservation and management on private unprotected forest lands. And the data can also be used in teaching and learning in geography, environmental studies, biology, mathematics, hydrology, and other disciplines, as we have written in the past here and here about teaching water topics using GIS.
Many of the layers from the Forests to Faucets program have been loaded into this web map, including watersheds, the importance of surface drinking water, and forest importance, insect, disease, wildlife, and development threats to forests important to surface drinking water. One of the things I’ve always loved about mapping is that the results often run counter to our preconceived notions. On the map below, I had been expecting to see evidence of fire threats to surface drinking water in California, but not in the southern Appalachian region. Think of the discussions that just this single web map can foster: What factors influence whether water is obtained chiefly from surface resources or from groundwater? What are the influences on forest health? What can be done to protect water quality? And GIS allows for the examination of other data layers and the use of spatial analysis techniques.
We always encourage students to be critical consumers of data. This data was created by the US Forest Service group responsible for publishing, cataloging, and managing the USFS’ authoritative enterprise content on ArcGIS Online. Does that mean the data is perfect? No, but the content includes only that which has been vetted and approved through a national governance process and by GIS and science professional staff.
For further investigation, see the other map layers published by this group, including wilderness areas, specific insect threats, and my favorite, the trends in burn severity back to 1984. For additional background, see the Forest Service’s resources and the The Nature Conservancy’s resources.