Washington Administrative Code › Title 220 - Fish and Wildlife, Department of › ENVIRONMENTAL STANDARDS AND CONSERVATION › Chapter 220-660 - Hydraulic code rules › Section 220-660-200 - Fish passage improvement structures

Current through Register Vol. 24-14, July 15, 2024
The provisions in this section apply to fish ladders, weirs
				  constructed for fish passage management, roughened channels, trap-and-haul
				  operations, and hydraulic design culvert retrofits.
(1)
Description:
Fish passage
				improvement structures facilitate the passage of fish through or around a
				barrier. They restore upstream and downstream fish access to habitats that have
				become isolated by human activities such as placing culverts, dams, and other
				artificial obstructions.
(2)
Fish life concerns:
Barriers can block fish from using upstream
				spawning and rearing habitat. The main goal is to remove fish passage barriers
				and ensure unimpeded passage of fish at all life stages, as well as to maintain
				natural channel processes and function. However, when it is not feasible to
				remove a barrier, a fish passage improvement structure may be an alternative
				mitigation measure. The department does not generally recommend using fish
				passage improvement structures because they can be partial barriers to fish
				passage and generally require maintenance. Fish passage improvement structures
				that mainly pass one species or class of fish may unintentionally limit the
				passage of other species.
(3)
Fish passage improvement structure design:
(a) Fish passage improvement structures
				should not be used to bypass permanent natural barriers except in limited
				situations where they are needed to restore native fish species.
(b) A person must provide site and biological
				information relevant to the specific project, such as information on species
				present, hydrology and topography, and existing adjacent structures.
(c) The department may require compensatory
				mitigation if a fish passage structure cannot pass all fish species present at
				all mobile life stages.
(d) The
				design must consider site-specific conditions that could affect the function of
				the fish passage improvement structure. These include meander migration or
				vertical change in stream bed elevation, debris and bedload movement,
				tampering, vandalism, and poaching.
(e) The fish passage structure design must
				withstand the maximum expected flow.
(f) The fish passage structure must not
				result in significant migratory delays as determined by the department or
				mortality to fish life due to disorientation, distraction, predation, stress,
				or injury.
(g) The fish passage
				structure must accommodate expected run sizes to prevent crowding and
				significant delay of fish migration as determined by the department.
(h) The department will determine the
				inspection interval depending on the type of fish passage improvement structure
				and watershed conditions.
(i) The
				department may require the installation of a temporary fish passage structure
				to provide passage through temporary obstructions. The department may not
				require a fish passage structure if a barrier exists for such short duration
				that the department determines that no lasting impacts to fish life will
				occur.