PNW REACH FILE TOOLS

The PNW Reach file includes a stream-based route system for referencing stream data and uses unique identifiers (LLIDs) to identify streams. In 2001, the National Hydrography Dataset (NHD) was completed through a joint effort of the U.S. Environmental Protection Agency and the U.S. Geological Survey. The NHD introduces a reach-based route system for referencing stream data. StreamNet, in cooperation with the EPA, has developed an application for converting data between these two systems (NHD and LLID). Also included at the application site are a set of NHD files with the LLID route system built onto them, and help documentation.

The PNW Reach Files carry the U.S. Environmental Protection Agency's (US EPA) reach codes. The result is a regional hydrography data set ready for use in a GIS package and portable to a spreadsheet or database system. If you do not have access to GIS software and would like to examine these files graphically, follow the instructions on how to use ARCEXPLORER, a free program which can view and query these files.

These files were prepared on a Windows NT platform, and if you have trouble importing them on a UNIX machine, you may need to use a UNIX2DOS translation program. A listing of frequently asked questions regarding these files and the process by which they were compiled is also available.