Formatted Title

Case Study: Implementing a PFAS Construction Management Plan (CMP) during a Major Airport Expansion Program

Background/Objectives

Austin-Bergstrom Airport (AUS) is beginning a decades-long Airport Expansion and Development Program (AEDP) in 2024, with many projects expected to disturb soil and/or groundwater contaminated with per- and polyfluoroalkyl substances (PFAS).  This case study examines the issues, technical approach and solutions involved in implementation of a PFAS CMP for the AEDP.

Approach/Activities

AUS was formerly occupied by Bergstrom Air Force Base from 1942 to 1993.  The base was closed and the Austin municipal airport was relocated to the site in 1999.  Site-wide remediation during the base closure resulted in the cleanup of several hundred, mostly minor, environmental sites.  Legacy PFAS issues were unexpectedly encountered by the City of Austin during construction of stormwater/deicing treatment ponds in 2016. The resultant construction delays and change order costs provided incentive to improve the management of future projects by developing a PFAS CMP in 2020.

AEDP will begin construction activities in mid-2024.  In preparation, our team has implemented and expanded upon the existing PFAS CMP.  In October 2022, a position statement for the management of PFAS-contaminated environmental media was completed and confirmed with the Texas Commission on Environmental Quality (TCEQ).  A Phase II Environmental Site Assessment for the first phase of construction (a new terminal, associated taxiways and other infrastructure improvements) was completed in June 2022.  A Soil and Groundwater Management Plan (SGMP) was completed in July 2023. 

Contract documents to bid and procure an on-call remediation contractor are currently in development and that contractor is expected to be available prior to the start of AEDP construction.

The City has also used this opportunity to coordinate the activities of various stakeholders/tenants at AUS, including the U.S. Air Force and Texas Air National Guard to avoid redundancy in site investigations and ensure a unified approach that aligns with current regulatory requirements.

Future activities will include continuous improvement of the PFAS CMP to reflect industry best management practices and current State/Federal regulations, tracking regulatory development and monitoring activities at other airports.

Results/Lessons Learned

A 2016 airport construction project was unexpectedly delayed and resulted in a $2.5 million dollar change order due to the unexpected discovery of PFAS groundwater contamination.  As a result, a PFAS CMP has been implemented for the AEDP. Every planned project will include a careful evaluation of the PFAS presence or absence and the necessary resources for handling, storage, and disposal of contaminated media will be in place well in advance of construction.