Case Study: Port of Portland T4 Storm Water Management

The Port of Portland is a leader in the use of innovative environmentally friendly storm water management systems. As a part of a larger citywide effort to go above and beyond baseline requirements, the Port of Portland showed their dedication to their surrounding environment by installing top of the line storm water systems in their Terminal 4 facility, ensuring that no polluted runoff would reenter the Willamette River without extensive treatment.

Toyota Logistic Services is a current tenant of Terminal 4 and are primarily responsible for the installation of the extensive storm water management systems. The Toyota facility provides a first point of rest for off-loaded vehicles, a processing plant where each car receives the necessary accessory installments, a holding area where the cars are parked before being transported, a rail loading facility, and a truck loading facility. A site of this size contains a significant amount of impervious surfaces, resulting in high runoff velocity and volume as well as the potential to pick up large amounts of sediment and pollutants.

Toyota Logistic Services Trucking Area

The trucking area of the Toyota facility contains three storm water structures that work together to ensure water leaving the trucking area polluted by oil and hydraulic fluids is suitable to enter the Willamette River. The map below highlights the trucking area, the curb inlets equipped with catch basin inserts, the oil water separators, and the bioswale. Based on the large amount of oil and other pollutants running directly into the curb inlet a storm water treatment system of this complexity appears necessary.

Curb Inlets w/ Catch Basin Inserts:

Toyota utilizes two different types of catch basin inserts at their facility. These inserts are used as pretreatment mechanisms to the downstream systems. The first is referred to as a “witch hat” made of geotextile fabric (learn more). The “witch hat” is utilized in the area North West of the trucking facility where there is no pollution coming directly from the trucks. The “witch hat” is primarily intended to capture sediment but can also hold up to 1.38 gallons of hydrocarbons. These units are typically under $100.

The second and more advanced catch basin insert system is a stainless steel insert with an oil and sediment filter (learn more). These inserts are used in areas adjacent to the trucking facility where the storm water picks up the greatest amount of oil. In this area spills from trucks are inevitable, and often times are not properly contained by the truck driver responsible. Toyota used a product called the Flo-Guard Plus manufactured by Kristar Enterprises. Kristar claims a 70% removal rate of oil and grease, 80% of TSS, 40% of total phosphorus, and captures debris and sediment. These units range from $650-700 per unit and require maintenance anywhere from once a month to twice a year depending on the environment.

Oil Water Separator w/ Coalescing plates:

After sediment and larger oil particles have been removed by the catch basin inserts, the storm water enters an oil water separator where it receives secondary treatment. Instead of using a traditional oil water separator that relies entirely on gravity to separate the oil and water, Toyota utilizes coalescing plates that increase the speed of the separation and also removes a greater amount of oil (learn more). VortClarex, an oil water separator with coalescing plates, manufactured by Contech, claims a 99% removal rate of oil droplets 60 microns or larger. Standard oil water separators typically only remove oil droplets larger than 150 microns.


After the water has passed through the catch basin inserts and the oil water separator with coalescing plates, the water flows into a bioswale planted with native grasses, shrubs, and trees. The main purpose of this bioswale is to cool and slow the water before it enters the river, but it can also filter out pollutants that were not removed by the previous two treatment systems. This feature made Toyota eligible for a Salmon Safe certification because it supports riverbank stability and prevents warm water from entering the river.

Toyota Logistic Services First Point of Rest (FPR)

The First Point of Rest at the Toyota facility is a large expanse of impervious pavement capable of holding thousands of new cars. Although the new cars rarely leak any fluids, the facility is located downhill from a road with heavy traffic from trucks and older vehicles as well as a major railroad line. For this reason Toyota installed three hydrodynamic separators called Downstream Defenders. Hydrodynamic separators utilize the vortex created by water moving in a swirling motion to remove particulate matter and oil and grease (learn more). Depending on the size, a Downstream Defender can handle a peak flow from 3-25 cubic feet/second ranging from $8,500-$43,500 per unit.

Terminal 4 Rail Yard Adjacent to Kinder Morgan

Kinder Morgan bulk terminal, a tenant of Terminal 4, transports large amount of soda ash and potash using the Union Pacific Railroad. However, being located on the Willamette River the Port of Portland takes precautions to minimize impacts to the river by using a top of the line storm water treatment system. The port utilized the StormFilter manufactured by Contech Stromwater Solutions. The StormFilter is a small cartridge filled with a filter media dependent on the target pollutant. This filtration system can remove particulate matter as small as 15 microns, whereas most other systems only remove particulate matter greater than 50-100 microns. The Port of Portland installed a vault configuration containing over 10 StromFilter cartridges, preventing the small particulate matter from the soda ash and potash from polluting the Willamette River.