A unit of Lasting Forests Sustained forests; sustained profits evolving since March 30, 1999

Watersheds are mappable. Most people can realize that what people above them on an area do can affect them. Water runs down. There is less interest in what will become of pollution when it leaves an area and runs down. Watersheds are one way for land managers to map and analyze land and related phenomena. They are primarily of value for analyzing runoff and sediments. This includes floods, dams, and recreational issues related to water such as fishing, swimming, boating, and sight-seeing or ranging. Given the wide spectrum of land use issues, the above is a small set. There are many issues and topics not related to runoff or silt. Many issues are political and political boundaries and jurisdictions do not follow watershed boundaries.

The conditions on one side of a stream within a watershed are not the same as on the other side. The rare exception does not deny the rule. There are differences in slopes, shade, soil, geology, precipitation...etc. To aggregate all of these differences into a single watershed unit is to over aggregate, to waste money in detailed data collection. At one scale (in the past) people had to make major generalizations. With computer aids, there is less need to do so.

The Alpha Unit is a map pixel or picture element. It is 30 meters by 30 meters in area (Universal Transverse Mercator projection). Throughout the world data bases exist that can provide over 20 map layers or factors about every Alpha unit in the world. There is now less need to aggregate. Areas can be managed pixel by pixel with discrimination. At lease the differences can be seen and noted. Perhaps the funds, access, etc. are not available but the modern manager starts with detailed knowledge and backs off from it as required by the practical dimensions of a situation. They do not start with an over-aggregation and generalization and desperately wish for more information in very difficult decision situations.

So What?

Watersheds do not have to be the land management unit. Any area can be selected and the realities of historical and political boundaries addressed. Watershed analyses (for runoff and silt) are needed but they are only one of many analyses needed for modern wildland management. The Alpha Unit requires detailed knowledge of the site to be used in the context of knowledge about ecology, economics, and other forces. It is past time for the over-generalizations and area exclusions (The area was in the management area but outside the watershed!) allowed by a watershed approach to be de-emphasized. Land use management will improve faster with the Alpha Unit approach than with that of the watersheds.

This Web site is maintained by R. H. Giles, Jr.
Last revision January 17, 2000.