Client: Simpson Timber Company, Shelton, WA.
Project Specifications: Simpson
Timber Company operates sawmills
in Washington and California
producing dimension lumber.
This project at the company’s
400-acre Shelton facility
involved two key on-site
improvements at the Simpson
Mill #5 and log-sorting yard.
The first was mitigation
of localized flooding affecting
the areas around the mill
during heavy rains. The second
was ensuring that the facility
as a whole met Department of Ecology stormwater discharge standards.
To meet those goals, Hatton Godat Pantier provided full stormwater retrofit design services,
including engineering of detention, treatment and conveyance systems.
Key Challenge: Although the Simpson Timber sawmill’s production technology
was “cutting-edge,” the ground adjacent to the log yard often turned into a
mud pit during heavy rains. The runoff drained into a storm pond, which emptied out into
a local creek. Though serviceable, the system was at risk of running afoul of state environmental regulations
and needed to be significantly upgraded.
The Point of Difference: “We
engineered a system using
large settling ponds and
a ‘decanting’ process
to settle out suspended particulates – i.e.,
mud,” said Steve Hatton. “After
the redesigned system was
engineered and constructed,
the client was able to meet
strict state and federal
NPDES guidelines for stormwater