Currently, the northern part of the runway and the runway safety area slope downward slightly more than FAA design standards allow. There are also humps, ruts and depressions, including Glencoe Swale, that are larger than allowed by current FAA standards.

Maintaining the existing condition allows the airport to operate Runway 13R-31L within an acceptable level of safety until the project can be completed.

The Port of Portland worked with the FAA to develop six different design alternatives to bring the runway and runway safety area into compliance with current standards. Alternatives considered included reducing the runway length, shifting the runway location, and redirecting Glencoe Swale, among other options.

The proposed alternative, the alternatives evaluated, and the screening results are available in the Draft EA and summarized on this website.

The NEPA schedule below outlines the environmental review process and timeline.

The Proposed Action would include the following:

• The slope (grade) of the northern 500 feet of Runway 13R and its runway safety area would be adjusted to meet current FAA standards.
• Taxiway A1 would be reconfigured and Taxiway A2 would be removed.
• Glencoe Swale would be realigned through a 500-foot-long box culvert, 14 feet wide by 6 feet high, through the runway safety area. This culvert would be designed to allow fish passage.
• A wildlife gate would be installed at each end of the culvert to keep wildlife, such as coyotes, from entering the culvert. Small wildlife, such as frogs, would be able to pass through the gates. The gates could be closed in the dry summer months and open during the wet, rainy season.
• Where fill material is needed to adjust the slope of the runway and runway safety area, material currently stored in stockpiles on the airport property would be used for a portion of the needed fill. A layer of topsoil would be imported.
• Filling in portions of the Glencoe Swale floodplain may have an impact on how much stormwater the swale can hold during a heavy rain event. To offset this impact, the project would create additional areas of flood storage along Glencoe Swale on the airport property to store and absorb stormwater.
• All construction work would occur within the boundary of the Hillsboro Airport. During construction, some construction vehicles would travel on local roads to haul materials.
• Construction best management practices (“BMPs”) would be implemented to minimize and avoid impacts during the construction process.
• All required permits would be obtained prior to construction.

Under the No Action Alternative, no improvements to the runway safety area and runway would be constructed. The runway safety area and north end of the main runway would continue to not meet current FAA design standards.

• The Proposed Action would avoid significant long-term impacts to water resources through the incorporation of mitigation measures.
• Glencoe Swale would be realigned and routed through an underground culvert across the runway safety area. Following realignment, the speed (velocity) of water flowing through the swale would be similar to the existing conditions.
• With a net reduction in the area covered by impervious surfaces (e.g., pavement, gravel), the project would result in an overall reduction in stormwater flowing off the airport property.
• Water quality filter strips (vegetated areas designed to remove pollutants and sediment) would be installed to manage water quality of stormwater from new and modified impervious (paved/gravel) surfaces to improve water quality.
• Changes to the floodplain associated with the segment of Glencoe Swale on airport property would not affect flooding upstream or downstream of the airport. The project would modify the existing 100-year floodway associated with Glencoe Swale. The additional fill within the runway safety area would result in the loss of flood storage, but this would be offset by an equivalent amount of compensatory storage created upstream and downstream of the new culvert and would occur entirely on the airport property.
• With the proposed grading changes, there would be a decrease in ponding area when water levels are at their highest; less standing water should reduce the attractiveness of Glencoe Swale to waterfowl compared to existing conditions, improving safety for aircraft operations.
• Rerouting Glencoe Swale to create a smooth surface in the runway safety area would require filling of some wetlands, vegetated corridors (wetland and stream buffers), and portions of Glencoe Swale. Permanent impacts to wetlands, streams, and vegetated corridors would be offset through in-kind, off-site (not on airport property) compensatory mitigation at local mitigation banks.
• During construction, Glencoe Swale would be temporarily diverted into a pipe and pumped around the construction area.
• The floodplain associated with Glencoe Swale would be disrupted during construction while the swale is being rerouted and the compensatory flood storage areas are being excavated; however, construction would occur during the driest months of the year when Glencoe Swale has minimal or no flow. By fall, when rain becomes more frequent, construction would be completed.
• Vegetated areas temporarily disturbed during construction would be restored in place by reseeding after grading is complete. Temporarily-disturbed wetlands and portions of Glencoe Swale would function the same as before construction.
• Erosion control measures would be implemented to minimize construction runoff, erosion, and sedimentation that could result from construction activities, such as pavement removal and excavation.
• Construction fencing would be installed to protect existing water resources and vegetated corridors outside of the construction limits.

• The Proposed Action would have no long-term impact on noise levels.
• Runway conditions would be the same before and after the Proposed Action is constructed, with no change in aircraft operations, therefore no long-term direct or indirect noise impacts would result from the Proposed Action.
• During construction, south of the airport near the end of Runway 31L there would be negligible changes in aircraft sound levels of less than 1 decibel. The criteria for significant impact is a 1.5 decibel or greater increase in noise levels.

• The Proposed Action would have no long-term impacts on federally-listed fish and wildlife species or their designated critical habitats.
• Wetland and stream habitat converted to grassland as a result of relocating Glencoe Swale into a culvert, would be replaced through in-kind, off-site compensatory mitigation to ensure no net loss of habitat in the watershed.
• The new culvert would be designed to meet Oregon Department of Fish and Wildlife’s fish passage requirements, which would result in an improvement to in-stream habitat quality for fish species, should they occur in the future.

• The Proposed Action would have no long-term or short-term (construction related) impacts on cultural and historic resources.
• A cultural resources survey, including the excavation of 40 shovel probes within the project area, found no historical, architectural, archaeological, or cultural resources present in the area of potential effect where construction would occur.