McElmo Creek Main Flare PSD Permit Application : McElmo Creek Main Flare PSD Permit Application :Visibility Impact Visibility Impact Visibility Impact /Soils 

and Vegitation Analyses

Andrew Chew Andrew Chew to: Dmallory 01/30/2013 03:00 PM

Dwight,

Per our phone conversation, as our office is wrapping things up in preparation for public notice , here are 2 

more topics we hope Tom can help make our write-up more robust:

 Visibility Impact Analysis

The visibility impact analysis for fulfilling the additional impacts analysis requirement pertains to visibility 

impairment (e.g., plume blight) in Class II areas. My understanding from Don Shepard is that Hovenweep 

is the only Class II federal area within 50 km of the Main Flare. The analysis should include Class II areas 

described below.

The Class II visibility impacts analysis is independent of the Class I visibility Air Quality Related Values . 

Please confirm whether there are other Class II federal and state areas (e.g., potentially sensitive parks, 

forests, monuments, and recreational areas) within 50 km of the project. (If there is not a specifically 

designated "Class II area(s)", the project should consider a location(s) where there may be some 

potential for visibility impairment . For instance, if there is an area where there are terrain features that 

provide a contrast that makes changes in visibility perceptible , that area may be considered.) 

Please discuss the potential visual impacts of the project on these areas . Information presented in the 

EPA 1992 workbook should be considered -

 U.S. EPA (U.S. Environmental Protection Agency), 1992. “Workbook for Plume Visual Impact 

Screening and Analysis.” EPA-450/R-92-023. October.

http:// http://tinyurl tinyurl tinyurl .com/EPA1992plume

Then based upon the evaluation, conduct a VISCREEN Level 1 analysis (beyond what already was 

provided for Class I areas) for any identified areas. If necessary, conduct a Level 2 analysis if the Level 1 

impacts are exceeded. If there is a valid reason not to conduct an analysis, please provide that narrative.

 Soils and Vegetation Analysis

Please characterize the potential impacts to soils and vegetation in consideration of the following 

suggested additional references to help make the write-up more robust: 

 U.S. EPA (U.S. Environmental Protection Agency), 1980. “A Screening Procedure for the 

Impacts of Air Pollution Sources on Plants, Soils, and Animals. Final Report” 

EPA-450/2-81-078. December.

http://tinyurl.com/EPA1980Soils

Web Soil Survey (WSS) for the National Cooperative Soil Survey via the USDA Natural Resources 

Conservation Service. 

http:// http://websoilsurvey websoilsurvey websoilsurvey .nrcs.usda.gov/app/HomePage HomePage HomePage.htm

From site: 

Web Soil Survey (WSS) provides soil data and information produced by the National 

Cooperative Soil Survey. It is operated by the USDA Natural Resources Conservation 

Service (NRCS) and provides access to the largest natural resource information 

system in the world. NRCS has soil maps and data available online for more than 95 

percent of the nation’s counties and anticipates having 100 percent in the near future. 

The site is updated and maintained online as the single authoritative source of soil 
survey information.

Links to recent EPA Region 9 Fact Sheets that include discussions about soils and vegetation , as 

examples of what we have proposed in our permits, are as follows: 

 Pio Pico, Item IV.2 - 

http://www.regulations.gov/#!documentDetail;D=EPA-R09-OAR-2011-0978-0005

 Palmdale - http://www.regulations.gov/#!documentDetail;D=EPA-R09-OAR-2011-0560-0004

 SPI Anderson - http://www.regulations.gov/#!documentDetail;D=EPA-R09-OAR-2012-0634-0003

Please let me know if you have further questions. Thank you.

- Andrew 

 -------------------------------------------

Andrew Chew, P.E. 

T: (415) 947-4197 | F: (415) 947-3579 | chew.andrew@epa.gov

U.S. EPA, Region 9, Air Permits Office (AIR-3) | 75 Hawthorne St., San Francisco, CA 94105