Washington Administrative Code
Title 220 - Fish and Wildlife, Department of
ENVIRONMENTAL STANDARDS AND CONSERVATION
Chapter 220-660 - Hydraulic code rules
Section 220-660-270 - Utility crossings in freshwater areas
Universal Citation: WA Admin Code 220-660-270
Current through Register Vol. 24-18, September 15, 2024
(1) Description: Utility lines are cables and pipelines that transport gas, telecommunications, fiber optics, power, sewer, oil, and water lines from one side of a watercourse to the other. An HPA is not required for utility crossings attached to bridge structures.
(2) Fish life concerns:
(a) Utility crossings pose a
risk to fish life and the habitat that supports fish life from potential
substrate changes, destabilization of stream banks and channels, loss of
riparian zone vegetation, and release of excessive sediment after stream flows
resume. Utilities not buried below bed scour depth can require rock to protect
them. This reduces habitat, inhibits channel processes, and can become fish
passage barriers due to the rock or the pipeline.
(b) Trenching through stream banks and
channels alters habitat and substrate characteristics, and therefore their
productivity and should be avoided. Trenching may also cause the proportion of
surface and subsurface flows to shift, altering stream hydrology. The
department prefers trenchless crossing methods such as high-pressure
directional drilling or punch and bore crossings that cause very little
disturbance to the stream bed and banks.
(3) Utility line design:
(a) Align the conduit as perpendicular as
possible to the watercourse.
(b)
Avoid crossing at meander bends, braided streams, alluvial fans, active flood
plains, or any other area that is inherently unstable and may lead to eroding
and scouring the stream bed.
(c)
Avoid areas of groundwater upwelling or locations within one hundred feet
upstream of documented fish spawning areas.
(4) Utility line construction:
(a) Install the conduit well below scour
depth of the watercourse to prevent natural scouring of the stream bed from
exposing the pipeline or cable.
(b)
If construction involves boring or jacking:
(i) Isolate pits from surface water flow to
prevent bore hole collapse; and
(ii) Before discharging wastewater to state
waters, route wastewater from project activities and dewatering to an area
outside the watercourse to allow removal of fine sediment and other
contaminants.
(c) If
construction involves trench excavation:
(i)
Trench widths should be as narrow as feasible to accommodate the pipe/line and
achieve the depth specified in the approved plan.
(ii) Excavate trenches in the dry or isolate
them from the flowing watercourse by installing a cofferdam, culvert, flume, or
other approved method;
(iii)
Plowing, placement, and covering must occur in a single pass of the
equipment;
(iv) Limit disturbance
of the bed and banks to the amount needed to complete the project. Before
returning flow, backfill trenches with approved materials and return the bed to
preproject condition.
(v) Dispose
of excess spoils upland or on a barge so they will not reenter waters of the
state.
(vi) Isolate the conduit
approach trench from the watercourse until the conduit is laid across the
watercourse.
(d) If
construction involves directional drilling:
(i) Design the drill path to an appropriate
depth below the watercourse to minimize the risk of frac-out and to a depth to
prevent exposure of the line from natural scouring of the stream bed;
and
(ii) Locate the drill entry and
exit points away from the banks of the watercourse to minimize impact on these
areas.
Disclaimer: These regulations may not be the most recent version. Washington may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
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