Stormwater Underground Injection Control (UIC) Remediation

ESA  Image

The City of Portland, Oregon, has approximately 9,000 underground injection controls (UICs) that collect stormwater from public rights-of-way and discharge the water below ground. The continuous operation and maintenance of UICs, and compliance with Department of Environmental Quality (DEQ) regulations, are critical to Portland’s comprehensive watershed strategy of using stormwater as a resource.

ESA provided hydraulic and hydrologic engineering services for 25 sites in southeast Portland to bring the facilities into compliance with DEQ standards. Stormwater has been managed historically by collecting runoff from roadways and discharging it into the UIC systems. We provided abandonment and shallowing of UICs, design of subsurface infiltration facilities, and design of green street facilities throughout these sites. Recently, we were contacted to provide engineering services for an additional 56 UIC sites. Our team reviewed existing predesign information, provided infiltration testing, coordinated right-of-way improvements, and prepared plans, specifications, quantity takeoffs, engineering cost estimates, and bid document support.

After our team completed 60 percent design and construction drawings, DEQ notified the City that the separation distance between seasonally high groundwater and the bottom of the UIC could be reduced from 10 feet to 5 feet. We evaluated the implications of this new separation requirement and found that it would significantly reduce the amount of work necessary to make the existing 56 UIC facilities compliant with DEQ regulations. We tested the existing capacity of 10 facilities within the project and developed a method for estimating the reduced capacity of a shallowed UIC.

ESA partnered with the City of Portland to bring into compliance 76 UICs, helping to prevent, minimize, and control pollutants at the surface before stormwater is discharged to the ground.

Specialized Services

  • Clean Water Act
  • County and city regulations and mandates
  • Design specifications and construction bid packages
  • Engineering design and construction documents
  • Hydrologic assessments
  • Rainfall-runoff modeling
  • Runoff management plans
  • Stormwater management