Att_04_Soil_Temperatures___Gas_Mntrg_Rpt.pdf

Tetra Tech

P.O. Box 30615, Billings, MT 59107 618 South 25th Street, Billings, MT 59101

Tel 406.248.9161 Fax 406.248.9282 www.tetratech.com

July 30, 2010

Mr. Mark Siedlaczek Project Manager - Engineering Xanterra Parks and Resorts P.O. Box 587 Yellowstone National Park, Wyoming 82190 msiedlaczek@xanterra.com

Subject: Summary Report - Soil Temperature and Gas Monitoring

Laurel Dormitory Old Faithful, Yellowstone National Park Tetra Tech Project No. 550365.100

Dear Mr. Siedlaczek:

Tetra Tech is pleased to present this report summarizing the results of soil temperature and gas monitoring conducted at the Laurel Dormitory site located at Old Faithful, Yellowstone National Park, Wyoming (Figure 1). The monitoring included the measurement of soil temperatures and concentrations of geothermal gases, including carbon dioxide (CO2) and hydrogen sulfide (H2S). This monitoring event was conducted in accordance with Tetra Tech’s Proposal to Conduct Soil Gas Monitoring, Laurel Dormitory, Building, Old Faithful, Yellowstone National Park, Wyoming dated May 12, 2010. The following sections presents a detailed description of the sampling methods used for collection of data, results, and comparisons to the current National Park Service (NPS) Hydrothermal Resource Protection Criteria of Cessation of Old Faithful Kitchen/Laundry Renovation Project Criteria 2 and 3 standards.

METHODS

Tetra Tech personnel Mr. Shane Ewert and Mr. Shawn Reinhart conducted soil gas and temperature monitoring at the site during June 7-22, 2010. Prior to collection of data, the investigation area was delineated into a grid with sample points defined on ten feet by ten feet centers. These drill points’ geoposition coordinates were recorded using a Topcon®

Model GR3E12-XT geographic positioning system (GPS) unit with a horizontal precision of

0.033 feet and the datum NAD 1983 Wyoming State Plane. Three-quarter inch diameter holes were drilled in each delineated test area using a rotary hammer drill with 36-inch drill bit. Each test area was drilled to ten-inch intervals with a final depth of thirty inches. Figure 2 shows the boring grid layout; and all sample locations are included in Table 1.

Measurements of CO2 and H2S concentrations and soil temperature (degrees Fahrenheit) were collected at 10-inch, 20-inch, and 30-inch depth increments and recorded on a field sheet (Attachment B). The temperature data was converted to Celsius using a Microsoft Excel® spreadsheet. CO2 concentrations were measured using a RKI® EAGLE 72-5401RK gas monitoring unit. H2S concentrations were measured using a RAE® QRAE2P.

Temperature was measured using a TCI Velocicalc® meter. The CO2 and H2S instruments mailto:msiedlaczek@xanterra.com

Xanterra Parks and Resorts were factory calibrated by TRS Environmental on June 2, 2010 (Attachment A) and re-checked daily to zero ambient air conditions.

CO2 measurements were measured in the field as a percent in air volume and following collection converted to parts per million (ppm) and using the following formula:

1% CO2 by volume = 10,000 ppm, so Result x 10,000 = total ppm

H2S concentrations were measured in the field in ppm. Several borings were not drilled or dvanced to the full 30-inch depth for the following reasons: a the boring location was in close proximity to potential underground utilities;

the boring location was obstructed by a parked vehicle which could not moved as the owner could not be located;

water was encountered in the boring;

the clay confining layer was encountered;

an obstruction was encountered during drilling and the drilling depth could not be advanced; or the boring location was in a large surface water puddle.

The crawl space beneath the Laurel Dormitory building was also tested during this investigation. Tetra Tech drilled 29 borings on approximately 10 foot centers to depths of 30 inches using the same procedures and equipment as for the outside drill points (Figure 2).

Additional soil borings could not be drilled in the crawl space due to space limiting issues such as water and sewer utilities constricting the height, less than two feet of available crawl space, or standing water.

Copies of the field reports are included in Attachment B. Pertinent site photos are included in Attachment C. The GPS Shape files in Universal Transverse Mercator (UTM) Zone 12 units are included in Attachment D.

RESULTS

Results from the June 2010 subsurface gas testing are presented in Table 1. Figures 3 through 6 show the carbon dioxide and temperature data for the 10-inch and 20-inch boring depths. Due to the limited data collected at the 30-inch depth, figures depicting the carbon dioxide concentrations and temperature values were not prepared. For the 10-inch boring depth the summary statistics are as follows:

Soil temperatures ranged from 12.4 to 43.9 degrees Celsius;

The average soil temperature was 22.9 degrees Celsius;

Carbon dioxide concentrations ranged from zero to 196,000 ppm;

The average carbon dioxide concentration was 10,046 ppm; and Hydrogen sulfide was only detected in Drill Hole O13 at 24.1 ppm.

For the 20-inch boring depth the summary statistics are as follows:

Soil temperatures ranged from 16.7 to 50.6 degrees Celsius;

The average soil temperature was 27.5 degrees Celsius;

Xanterra Parks and Resorts

Carbon dioxide concentrations ranged from zero to 422,000 ppm;

The average carbon dioxide concentration was 34,474 ppm; and Hydrogen sulfide was only detected in Drill Holes P70 at 70.0 ppm and Q19 at 25.6 ppm.

For the 30-inch boring depth the summary statistics are as follows:

Soil temperatures ranged from 18.6 to 56.7 degrees Celsius;

The average soil temperature was 31.7 degrees Celsius;

Carbon dioxide concentrations ranged from zero to 174,000 ppm;

The average carbon dioxide concentration was 23,014 ppm; and Hydrogen sulfide was not detected in any drill holes.

CO2 concentrations detected during the gas testing exceed the National Park Service (NPS) Hydrothermal Resource Protection Criteria of Cessation of Old Faithful Kitchen/Laundry Renovation Project Criteria 3 standard of 800 ppm at approximately 92 percent of the soil borings. Temperatures recorded were in excess of the Criteria 2 standard of 35 degrees Celsius (95 degrees Fahrenheit) in approximately 12 percent of the soil borings.

Approximately 31 drill points at the 20-inch depth had carbon dioxide concentrations greater than 10 percent (100,000 ppm) and these locations appear to be scattered in the investigation area. However, a limited number of temperature values greater than 35 degrees Celsius at the 20-inch depth appear to be located in the building crawl space and on the north side of the building.

Tetra Tech appreciates the opportunity to provide this service to you, and we look forward to providing industrial hygiene services to you on future projects. If you should have any questions or need any additional information, please feel free to call Paul Lemire or Jeffrey Rice in our Billings, Montana office at (406) 248-9161.

Respectfully Submitted, Tetra Tech

Paul E. Lemire Jeffrey R. Rice Project Scientist Environmental Group Manager

PEL/JRR/ba

N:\TYPING\ENV-FAC\550365\Xanterra OFI Laurel Dorm Report\Summary of Soil Temperatures and Gas Mntrg Rpt.doc

Attachments: Figures

Table Attachment A: Field Instrument Calibration Certificates Attachment B: Field Notes Attachment C: Site Photographs Attachment D: GPS Shape Files

FIGURES

TABLE

ATTACHMENT A

FIELD INSTRUMENT CALIBRATION

CERTIFICATES

ATTACHMENT B

FIELD NOTES

ATTACHMENT C

SITE PHOTOGRAPHS

Old Faithful Laurel Dormitory Soil Temperature and Gas Monitoring

Project No. 114-550365.100

PHOTOGRAPH 1 Gas testing equipment. PHOTOGRAPH 2 Drill points facing east.

PHOTOGRAPH 3 Drill points facing southeast. PHOTOGRAPH 4 Gas collection at drill point.

PHOTOGRAPH 5 Drilling boring.

PHOTOGRAPH 6 Drill points on north side of Laurel

Dormitory.

Old Faithful Laurel Dormitory Soil Temperature and Gas Monitoring

Project No. 114-550365.100

PHOTOGRAPH 7 Crawl space under Laurel

PHOTOGRAPH 8 Crawl space under Laurel

PHOTOGRAPH 9 Drainage channel in crawl space under Laurel Dormitory.

PHOTOGRAPH 10 Access to the west addition.

PHOTOGRAPH 11 Drainage channel in crawl space under Laurel Dormitory.

PHOTOGRAPH 12 Crawl space in west addition.

ATTACHMENT D

GPS SHAPE FILES