Project Description

Ship Building and Repair Facility, Washington

Dakota Creek Industries, a large ship fabrication facility in Anacortes, Washington, sought the input of a local consulting engineering firm to install stormwater treatment for the facility to reduce concentrations of zinc, copper, suspended solids and turbidity to below the stormwater benchmarks. The engineering firm recommended StormwateRx to design and supply the industrial stormwater treatment system that included two Aquip enhanced stormwater filtration systems to bring the facility into permit compliance.

TARGETED POLLUTANT: Copper, zinc, TSS, and turbidity


zinc b gone stormwater treatment


The Dakota Creek site encompasses roughly ten acres of mixed gravel and pavement surfacing. Each year additional gravel surface is paved as a structural stormwater best management practice and to improve operational efficiency; the new paved surface adds to the volume of runoff but reduces erosion and mass of pollutants generated. The challenges of this site were typical of most large fabrication facilities ̶ intensive industrial operations with heavy equipment, multiple pollutant point sources, both paved and gravel operating areas, buildings, fabrication areas, and material staging areas, and an evolving drainage system – all generating stormwater pollutants associated with industrial activities.

StormwateRx supplied two Aquip enhanced stormwater filters for the site – an Aquip 50SBE and an Aquip 210SBE. A detention tank located in front of the Aquip treatment systems enabled StormwateRx to provide treatment with a lower hydraulic capacity than is typical of a site of this size, at the expense of simplicity and loading capacity – the detention required the addition of pumps and controls, and more stormwater volume per unit treatment surface area was processed through the treatment system.

The StormwateRx treatment systems were able to reduce discharge concentrations to below the benchmarks.

Treatment Characteristics: Treatment sizing meets the Western Washington Hydrology Model stormwater sizing method that diverts approximately 91% of the annual average runoff volume through treatment.

Project Design Parameters

  • Industrial Processes:  Metal fabrication including cutting, grinding, welding, blasting, painting; engine work, fiberglass work, trucking, etc.  The facility includes a maintenance shop and administrative offices.
  • Drainage Characteristics:  Paved and unpaved surfaces totaling 10 acres.
  • Treatment Characteristics:  Treatment sizing meets the Western Washington Hydrology Model with approximately 91% of the annual average runoff volume being treated prior to discharge.


Filtration is meeting individual permit requirements.