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Site Report: Alyeska Dietrich Camp

Site Name: Alyeska Dietrich Camp
Address: Dalton Highway MP 210; 0.25 Mile W of Alyeska Pipeline MP 202.60; ~32 Mile NNE of Coldfoot, Coldfoot, AK 99701
File Number: 330.38.129
Hazard ID: 26323
Status: Active
Staff: Laura Jacobs, 9074512911 laura.jacobs@alaska.gov
Latitude: 67.681111
Longitude: -149.738611
Horizontal Datum:WGS84

We make every effort to ensure the data presented here is accurate based on the best available information currently on file with DEC. It is therefore subject to change as new information becomes available. We recommend contacting the assigned project staff prior to making decisions based on this information.

Problems/Comments

This site was formerly operated by Alyeska Pipeline Service Company as Dietrich Camp in the 1970s during the Trans Alaska Pipeline System construction. A total of at least 2,854 gallons of diesel, gasoline, hydraulic fluid, lube oil, and waste oil spilled due to camp activities. In October 2012, the Alaska Department of Transportation and Public Facilities was investigating the site for use as a gravel source and diesel contamination was discovered in two borings evident by hydrocarbon smell at the groundwater interface at 8 feet below ground surface. One soil sample collected at this depth contained diesel range organics at 1,260 mg/Kg and residual range organics at 73.7 mg/Kg. Note: the soil sample collected in November 2012 was not analyzed until February 2013.

Action Information

Action Date Action Description DEC Staff
12/23/2014 Site Added to Database A new site has been added to the database Mitzi Read
12/23/2014 Exposure Tracking Model Ranking Initial ranking with ETM completed for source area id: 79715 name: Miscellaneous Fuel Releases Mitzi Read
6/30/2015 Site Characterization Report Approved On this date, ADEC received the Revised 2015 Dietrich Camp Assessment Work Plan submitted by SLR and dated June 2015. Grant Lidren
3/11/2016 Site Characterization Report Approved On this date ADEC received the Dietrich Camp Assessment Report Dalton Highway Milepost 210 submitted by SLR and dated February 2016. A total of 63 soil borings were advanced to characterize the pad for potential reuse of gravel for DOT Dalton highway improvements. The locations of the borings included: at eight historical fuel storage locations, at the two DOT contaminated test holes discovered in 2012, and at nodes of a 177’ by 177’ grid. Additional borings were stepped out to characterize newly discovered contamination encountered at the southern edge to the pad. Based off field screening and groundwater interface, at least one analytical soil sample was collected from 22 of the 63 borings for a total of 34 soil samples. Contamination above cleanup levels was found at the southern portion of the pad in the subsurface within 2 feet of the groundwater interface. Groundwater was encountered at depths of 3.4 to 10.3 feet bgs throughout the pad. Twelve out of the 34 soil samples collected contained contaminant concentrations above method two cleanup levels with DRO up to 12,400 mg/kg, RRO up to 17,100 mg/kg, 1-methylnapthalene up to 12.6 mg/kg and 2-methylnapthalene up to 12.1 mg/kg. Contaminant concentrations above cleanup levels were not detected in surface soils. (note: at the north end of the pad at the diesel storage area, boring B2 contained DRO at 239 mg/kg (above the method one cleanup level of 200 mg/kg) with a PID head space of 7.3 ppm from a sample collected 0 to 1 ft. bgs. Additionally, adjacent borings D3 and D4 contained head space readings of 5.2 ppm (3 to 4 ft. bgs) and 2.7 ppm (1 to 2 ft. bgs) respectively). Analytical soil samples were not collected from D3 or D4. Grant Lidren
6/6/2018 Update or Other Action Email correspondence with DOT on this date. DOT does not plan to use Dietrich pad gravel for road work but, may in the future. If this is the case, ADEC must receive a gravel handling plan prior to field activities for ADEC approval in accordance with 18 AAC 75.325 Site Cleanup Rules. Grant Lidren
7/30/2018 Site Visit On this date, ADEC visited site. A DOT camp was present and gravel was being mined for Dalton Hwy roadwork. According to DOT, the mining areas were located so that the DOT would not be mining within the contaminated areas identified in the 2016 Final Dietrich Camp Assessment Report. ADEC was not notified prior to land disturbing field activities. Grant Lidren
7/5/2019 Site Characterization Workplan Approved On this date, ADEC received the Dietrich Camp Monitoring Well Installation Work Plan Revised submitted by SLR and dated July 5, 2019. Two borings will be advanced and completed as monitoring wells in 2021. Soil and groundwater samples will be collected. Grant Lidren
2/26/2021 Document, Report, or Work plan Review - other ADEC staff reviewed and approved the 2019 work plan to install two monitoring wells and collect samples just off of the camp pad to check groundwater flowing toward the dredge pond and Dietrich River for contaminants of concern. Laura Jacobs
8/2/2022 Document, Report, or Work plan Review - other The 2021 well installation and monitoring report was reviewed and approved. The 2022 proposed work plan was approved. DEC requests that the RP delineate the remaining groundwater contamination resulting from the two identified areas with elevated hydrocarbon levels in soils that were found in 2014. Laura Jacobs
6/23/2023 Document, Report, or Work plan Review - other The groundwater and surface water sampling report, received December 7, 2022 was reviewed and approved. Groundwater samples collected from the two monitoring wells resulted in detection of hydrocarbons but all below DEC cleanup levels. The concentration of naphthalene found in MW-1 decreased from a level above the DEC groundwater cleanup level in 2021 to below that concentration in 2022. Diesel range organics (DRO) was the only petroleum compound present in the sample collected from MW-2 but was well below the groundwater cleanup level. The surface water sample result from the gravel pit pond south of the pad had polycyclic aromatic hydrocarbons (PAHs) detected at low levels well below the DEC Alaska Water Quality Standard (AWQS). Laura Jacobs
6/23/2023 Document, Report, or Work plan Review - other DEC approved the 2023 Dietrich Camp Groundwater Monitoring Work Plan for continuing the groundwater and surface water sampling event at the site to ensure remaining petroleum contamination is not migrating to the Dietrich River. Laura Jacobs

Contaminant Information

Name Level Description Media Comments

Control Type

Type Details

Requirements

Description Details

No associated sites were found.

Missing Location Data

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