Definitions; In addition to the definitions in OAR
635-412-0005, for the purpose environmental restoration weirs the following
definitions shall apply:
(1) "Ancient
floodplain" means channel adjacent areas and surfaces constructed by fluvial
processes that functioned as floodplains or areas for overbank deposition prior
to channel incision.
(2)
"Applicant" means a person applying for the Department's approval of the
construction of an environmental restoration weir as defined in this
section.
(3) "Environmental
restoration weir" means one or more structures that are constructed:
(a) For the purpose of delaying or slowing,
but not preventing, streamflow to promote restoration of stream and habitat
conditions;
(b) Such that the
structures do not store or appropriate water in a manner that would require a
permit from the Oregon Water Resources Department;
(c) To be no larger than necessary to cause
overbank flooding onto the lands constituting the ancient floodplain during
ordinary periods of high streamflow. Ordinary periods of high streamflow are
times when the water elevations would reach the ordinary high water line in an
unaltered stream condition; and
(d)
From wood (including untreated fence posts), earth, dirt, rock or other natural
materials. Treated wood, metal, concrete, gabions or other engineered material
do not qualify as natural materials.
(4) "Healthy native migratory fish
population" means a population of native migratory fish that, as determined by
the Oregon Department of Fish and Wildlife:
(a) Demonstrates appropriate life stages
throughout the year; and
(b)
Reproduces at sufficient levels to be a self-sustaining population into the
foreseeable future.
(5)
"Incised or eroded stream" means a stream that has been scoured by erosion to
the extent that the channel bed elevation has lowered relative to its ancient
floodplain and the stream has lost connectivity with the ancient floodplain, as
characterized by:
(a) The loss of natural
wetland, riparian or meadow conditions in the adjacent surfaces;
(b) The absence of overbank flooding or
deposition during ordinary periods of high streamflow;
(c) The loss of historic diversity of native
fish or other species; or
(d) The
presence of dry land species that have encroached from adjacent uplands,
including but not limited to sagebrush, bunch grass, juniper and
pine.
(6) "Qualifying
stream" means an incised or eroded stream, a designated reach of an incised or
eroded stream or a designated set of adjacent reaches of an incised or eroded
stream that, prior to commencement of a project approved by the Department:
(a) Has an estimated median monthly natural
streamflow of less than one cubic foot per second during at least two months of
the year;
(b) Has not had a healthy
native migratory fish population for at least three years prior to the time of
Department approval; and
(c) Is
incised or eroded to the extent that the channel bed elevation has lowered by
two feet or more relative to the elevation of the ancient floodplain.
(7) "Reach" means a section of a
stream that is similar in flow topography and habitat characteristics and is
between 50 and 500 feet in length.
(8) "Summit of the Cascade Mountains" means a
line beginning at the intersection of the northern boundary of the State of
Oregon and the western boundary of Wasco County, thence southerly along the
western boundaries of the counties of Wasco, Jefferson, Deschutes and Klamath
to the southern boundary of the State of Oregon.