tech memo -eqt mvp railroad crossings construction - 2018-06 … · 2019. 9. 10. · below 55 dba...

SLR International Corporation, 6001 Savoy Drive, Suite 215, Houston, TX 77036‐3322 713 789 9400 slrconsulting.com

Technical Memorandum To: Mr. William Jones, P.E. Mountain Valley Pipeline, LLC

Engineer – MVP Compression Design Email: [email protected] Office: (724) 873-536 Cell: (304) 761-2079

From: Ronald R. Spillman, P.E. Principal SLR International Corporation 6001 Savoy Drive, Suite 215 Houston, Texas 77036 [email protected] Date: June 19, 2018 Subject: Construction Noise Study Pipeline Crossings at Rail Lines Sites in Virginia and West Virginia

1. INTRODUCTION

As part of the Mountain Valley Pipeline Project, Mountain Valley Pipeline, LLC will install pipeline under existing railroad tracks. Standard construction techniques will be used, but boring at the rail crossings will require 24-hour construction work due to railroad company safety requirements. As requested, SLR International Corporation (SLR) has modeled the anticipated construction noise for three crossings. Nighttime work is expected to last for only two to three days at any given crossing, but could extend to 14 days if problems are encountered.

2. SOUND LEVEL CRITERIA

As per the latest FERC guidance1 (FERC 2017), “Construction activity that would or may occur during nighttime hours should be performed with the goal that the activity contribute noise levels below 55 dBA Ldn and 48.6 dBA Leq, or no more than 10 dBA over background if ambient noise levels are above 55 dBA Ldn” at all surrounding NSAs. NSAs are typically residences, schools, churches, or hospitals.

In addition to the 55 dBA Ldn and 48.6 dBA Leq nighttime sound level targets, for this project, the nighttime construction contributions have been compared to the existing nighttime ambient sound levels, to calculate the short-term increases expected due to the construction equipment.

1 Federal Energy Regulatory Commission. Guidance Manual for Environmental Report Preparation for Applications Filed Under the Natural Gas Act, February 2017

June 19, 2018 Pipeline Crossing at Rail Lines Construction Noise Study

SLR International Corporation slrconsulting.com

3. NOISE SENSITIVE AREAS

Overnight sound monitoring was conducted at three crossings. These have been designated Railroad Crossings 2, 4, and 8. The Railroad Crossing locations, NSA distances, directions, and ambient sound levels for the monitored locations are summarized below. These locations are shown on the attached Figures 1 through 3.

Table 1: NSA Distance, Direction, and Ambient Sound Levels

Railroad Crossing Number, County, State, and Mile Marker

NSA Direction Distance,

feet

Measured Levels, dBA

Ambient

Ld Ln Ldn

2: Lewis Co, WV, MP 65.4

21 Southeast 1,850 47.5 44.2 51.2

3 East 2,400

4: Greenbrier Co., WV, MP 140.4

1 South 1,800 53.9 39.7 52.8

8: Montgomery Co., VA, MP 230.8

1 Southwest 370

44.6 42.6 49.3 2 Northwest 400

3 West 470

Note 1: “NSA 1” at rail crossing 2 was initially assigned to a location that is not actually an NSA.

4. NOISE IMPACT ASSESSMENT

4.1. Construction Equipment and Operation

The work at each rail crossing is expected to use the same or very similar equipment. An auger boring machine will be employed, and ancillary earthmoving and light plant equipment will be needed. The contractors estimate that 24-hour operation will be needed for two to three days at each crossing. The duration could extend up to 14 days if problems are encountered during construction. The pipeline construction beyond the rail crossing zones will take place during daytime only.

4.2. Construction Equipment Assumptions

The exact complement of construction equipment is not yet known. An auger boring machine will be used, similar to the Barbco HD48RCBM. That manufacturer reports that the auger produces 87 dBA at 20 feet. We applied standard engine spectral assumptions, and assumed that six light plants and two backhoes (or similar engine-driven earthmovers) will also be used at the rail crossings. Sound level data for the ancillary equipment was derived from the Federal Highway Administration’s Roadway Construction Noise Model (FHWA 2008)2. The sources were used as

2 FHWA (2008) Roadway Construction Noise Model, Federal Highway Administration, US Department of Transportation. Version 1.1, December 8, 2008.



inputs in a three-dimensional computer noise model developed using Cadna/A acoustical modeling software.

4.3. Predicted Sound Levels

Table 2 shows the predicted sound levels at the NSAs due to the noise contribution from the construction sites. Figures 4 through 6 show sound level contour maps of the predicted construction noise contributions overlaid on aerial photographs of Railroad Crossings 2, 4, and 8, respectively.

Table 2: Potential Short-term Sound Level Increase During 24-Hour Construction

Rai

lro

ad C

ross

ing

NS

A

Direction Distance

ft

Measured Levels, dBA

Predicted Sound Levels, dBA

Ambient Construction Contribution

Ambient Plus Construction

Potential Short-Term Increase

Ld Ln Ldn Ld Ln Ldn Ld Ln Ldn Ld Ln Ldn

2 2 Southeast 1,850

47.5 44.2 51.2 44.7 44.7 51.1 49.3 47.5 54.2 1.8 3.3 3.0

3 East 2,400 24.9 24.9 31.3 47.5 44.3 51.2 0.0 0.1 0.0

4 1 South 1,800 53.9 39.7 52.8 32.6 32.6 39 53.9 40.5 53.0 0.0 0.8 0.2

8

1 Southwest 370

44.6 42.6 49.3

61.4 61.4 67.8 61.5 61.5 67.9 16.9 18.9 18.6

2 Northwest 400 57.5 57.5 63.9 57.7 57.6 64.0 13.1 15.0 14.7

3 West 470 59.4 59.4 65.8 59.5 59.5 65.9 14.9 16.9 16.6

The sound level contribution of the railroad crossing construction is below 55 dBA Ldn at Railroad Crossings 2 and 4, and the short-term increase is less than 4 dBA, even at night. The anticipated noise impact is therefore barely perceptible or not significant at these crossings.

At Railroad Crossing 8, the railroad crossing construction contribution is predicted to exceed 55 dBA Ldn at each NSA, and there could be nighttime increases approaching 19 dBA over ambient while the crossing is being bored. Typical noise reduction treatments such as barriers could be prohibited, difficult, impractical, or unsafe for this application. Railroad companies and the Federal Railroad Administration have restrictions regarding structures near tracks, which limits the ability to place noise barriers effectively. In view of the short duration of construction, and the limitations noted, Mountain Valley will offer temporary relocation compensation to the impacted NSAs at Railroad Crossing 8; however, construction at this crossing is not contingent on the residents’ acceptance thereof.

5. CONCLUSION

SLR has monitored daytime and nighttime ambient sound levels at three pipeline railroad crossings with regard to the Mountain Valley Pipeline Project. Construction work will be required during nighttime hours for a few days, while boring is done under these rail crossings. The construction is



not expected to produce a significant impact at Railroad Crossings 2 or 4, but the short-term construction contribution at Railroad Crossing 8 will exceed 55 dBA Ldn and will cause a nighttime increase of almost 19 dBA. Due to the short duration of nighttime construction and restrictions involving noise barriers near railroad tracks, Mountain Valley will offer temporary relocation compensation to the NSA residents near Railroad Crossing 8 during boring activities

.



Figure 1: NSA Locations and Distance from Railroad Crossing 2 Construction Site



Figure 4: Railroad Crossing 2 Construction Noise Contour

tech memo -eqt mvp railroad crossings construction - 2018-06 … · 2019. 9. 10. · below 55 dba...

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