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Watershed Assessment Manuals
OR Watershed Assessment Manual
Each chapter of the manual is available for download in PDF format. For further information, please call (503) 986-0178.
Ecoregion Descriptions
This appendix includes information on interpreting watershed conditions; ecological characteristics of Oregon's ecoregions; and descriptions of potential riparian conditions, disturbance regimes, hydrologic conditions, stream channel types and other characteristics of watersheds in each ecoregion. The Riparian and Hydrology sections of the manual utilize this information to simplify their assessment process. Addendum 1 at the end of this document gives the percentage of watershed area for each fifth-field watershed in Oregon by Ecoregion type.
Hydrologic Process Identification for Eastern Oregon
Analysts conducting watershed studies should understand which types of hydrologic processes are producing peak flows in their watershed prior to selecting appropriate analysis tools.​ This appendix provides background information on both the season in which peak flows occur and the type of hydrologic processes which generate peak flows in Eastern Oregon. Peak flow increases in response to land use activities can be problematic if they alter the channel geometry and subsequently produce negative impacts to aquatic habitat. 
Hydrologic Process Identification For Western Oregon
This appendix identifies the hydrologic processes which produce peak flows throughout western Oregon and ​basic information about the types of flood events occurring in a watershed. The analysis of peak flows and changes in their magnitude is often undertaken to assess land use impacts on aquatic resources. Peak flow increases in response to land use activities may alter the channel geometry which could have potential negative impacts on habitat. (September 1998- courtesy of Boise Cascade)
Estuary Assessment

This estuary assessment and prioritization method constitutes Component XII of the Oregon Watershed Assessment Manual. This module can serve as a stand-alone method, but is best used as a component of the larger assessment. Introductory material in this document describes the basic characteristics and functions of estuaries and tidal wetlands. The remainder of the document outlines the estuary assessment in seven steps.  
Estuary Assessment (PDF)