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2.1.1 Narrative
Refer to prior POLREPS
2.1.2 Summary of Response Actions
Only the pup tank was overturned
during the incident. The rear compartment of the overturned trailer
contained approximately 1,700 gallons of “E-10” unleaded gasoline. This
compartment was compromised during the incident and subsequently released
gasoline into the north road side ditch for an estimated duration of 6 hours at
a rate of approximately 2 gallons per minute through a small hole.
Absorbents were deployed along the road side ditch to recover standing product. A temporary
catchment basin was constructed tocapture the gasoline as it was
released from the tank. Product recovery from the catchment basin was
conducted using a pneumatic diaphragm pump at a rate corresponding to the flow
rate from the compromised vessel. The catchment basin was effective in
providing near complete recovery of the remaining product in the ruptured
tanker with only occasional, de minimus additional losses of product to soils
once recovery efforts were initiated.
Additional emergency response and
recovery actions at the site conducted by various agencies included deployment
and collection of absorbent materials in the roadside ditch, offloading of all
accessible product from the trailer, deploying 200’ of absorbent boom along the
riverbank adjacent and downstream of the release site, and assessing the riverbank for any visual evidence of hydrocarbon sheen or
product. A total of six, 55-gallon drums of saturated absorbents were
collected by WCEC personnel during product recovery activities.
City Service Valcon provided an
Updated Incident Product Reconciliation which indicated that 35 gallons of
Clear Diesel and 1,169 gallons of Unleaded E-10 gasoline were lost during the
incident. Based on data obtained from the Updated Incident Product
Reconciliation and the volume of product contained in the absorbent materials,
the volume and nature of the release is believed to have consisted of
approximately 1,000 gallons of Unleaded E-10 gasoline.
Excavation & Monitoring
Excavation of impacted soils from
the north roadside ditch line was conducted on November 21 & 22, 2011
according to the approved Initial Cleanup Action & Investigation Work
Plan [WCEC, 2011] and Idaho Transportation Department (ITD) Encroachment
Permit. Approximately 184 cubic yards of impacted soils were removed
during the excavation and delivered to the Bob Jackson licensed landfarm
facility in Kooskia, Id for disposal.
Following the excavation at the
release site, the following monitoring and sampling was performed along the
Lochsa River in accordance with the Revised Technical Memorandum (RTM)
[WCEC, 2012]. :
· Weekly, then monthly river shoreline and rock
slope assessment and monitoring which continued through September 2015. A
total of 62 follow-up river shoreline and rock slope assessments were conducted
from December 2011 through September 2015;
· Periodic surface water monitoring at 3 locations
along the Lochsa River as specified in the RTM. A total of 8 surface water
sampling events were conducted from November 2011 to September 2015;
- Evaluation
of the results of the surface water sampling events and initiation of the
appropriate Pathway as specified in the Site Decision Process outlined in
Section 7.2 of the RTM;
- Preparation
and submittal of Surface Water Monitoring Reports following each sampling
event, with the final report issued in October 2015;
Completion
Assessment and monitoring
activities conducted following the cleanup actions at the site have demonstrated attenuation of gasoline derived constituent
concentrations in all environmental media impacted as a result of the release.
No free product or sheen was ever noted in the Lochsa River
including during the initial response activities, excavation, initial surface
water monitoring, or the 62 follow-up river assessment events conducted from
December 2011 through September 2015. No detections of gasoline
constituents have been noted at the Downstream sampling point of compliance
throughout site history. Constituent concentrations at the Boom sampling
location have remained below IDTLs and aquatic ecological health standards for
the last three surface water monitoring events beginning in August 2014. These
data indicate that any residual impacts remaining in soils upslope of the
Lochsa River do not pose a threat to surface water quality or aquatic
environments. No further action is required.
2.1.3 Enforcement Activities, Identity of Potentially Responsible Parties (PRPs)
Refer to prior POLREPS
2.1.4 Progress Metrics
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