On 20 Sep 06, an Associated Petroleum Products (APP) fuel truck slid off the road and over an embankment at Howard Hanson Dam. Incident resulted in the release of approximately 600 gallons of #2 diesel fuel into the soil. The tanker truck has been removed from site.
Initial soil analysis predicted that the fuel would quickly move vertically through the soil until it reached the water table.
This fuel has traveled from the spill site to the reservoir shore. Temporary measures have been put in place to minimize the fuel impact to the water. This has been accomplished with a series of trenches dug with absorbent materials placed in them and also a combination of oil only absorbents and rigid containment boom.
• Site access has been reestablished since the floods in November. Sheen monitoring was conducted during the duration of the high water period. No sheen was observed on the pool reservoir or in the groundwater wells during the flood event.
• Additional groundwater samples were collected on November 10, 2006 two days after highest water elevation. Sample results were not detected for constituents of concern.
• Booms have been removed from the site. TPU will be responsible for the monitoring for sheen in the future.
• On December 14,2006 a meeting was held telephonically between Ecology, EPA, TPU, Whatcom, APP, and USACE to discuss future monitoring requirements. All concurred that based on the results of the infiltration test, the future action at the site would be monitored natural attenuation. Ecology expressed concerns with respect to changes in flood elevation and seasonal variations as they related to potential releases of contaminants. Ecology requested that three additional months of sampling be conducted starting in January to evaluate the variation of dissolved releases at the site. Groundwater and reservoir samples will be collected when the pool elevation is below 1140’ for at least 48 hours. Samples will be collected for TPHD, TPHG, and BTEX. Groundwater elevation, pool elevation and rainfall during sampling will also be recorded.
• Whatcom will then present a summary of the results in memorandum form in March 2007. Frequency and type of additional data needed following the 3 months will be discussed following review of the data. At a minimum, quarterly samples will be required for one year.
• Data on the next 3 months of sampling will be provided to the team by Whatcom as it becomes available.
• TPU will continue to monitor for the presence of sheen in the reservoir. Potential for erosion on the slope will also be monitored. Updates on observations will be provided to team if they occur.
None anticipated.
This represents the final polrep for the site, as this release is no longer emergency in nature. Future coordination between parties on long term monitoring requirements will be held via phone calls and email if necessary.
None.
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