The objective of this assessment is
to provide resource managers and area stakeholders with a summary document of the
pertinent scientific information that will help them prioritize future assessment and project
action in salmon habitat planning and decision making. This report focuses on Catherine
Creek, from its confluence with the Grande Ronde River to the confluence of the North
and South Forks of Catherine Creek. The work described in this report was accomplished
by a multidisciplinary team with expertise in fisheries, vegetation, and physical processes
(hydraulics, hydrogeology, geomorphology, and hydrology). All work was coordinated
with local stakeholder involvement that consisted of meetings with an interdisciplinary
team (IDT).
As a result of this tributary scale assessment, the 55-mile area is subdivided into three
valley segments and seven geomorphic reaches that distinguish sections of Catherine
Creek with relatively distinct physical characteristics. The lower valley segment, from the
mouth at the Grande Ronde River to near Pyles Creek contains two distinct reaches (reach
1 and reach 2) that are separated due to the redirection of the Grande Ronde River into
State Ditch. The middle valley segment contains one unique reach (reach 3) that consists
of the Catherine Creek alluvial fan, beginning just upstream of the mouth of Pyles Creek,
and ending just upstream of Union, Oregon. The mountainous upper valley segment is
segregated into four reaches (4, 5, 6, and 7) based on lateral valley confinement; reaches 4
and 6 are unconfined with moderate floodplain interaction, while reaches 5 and 7 are
confined and naturally have little to no floodplains.
