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Chang, Andy

From: Clark, Adam

Sent: Tuesday, February 09, 2016 7:10 PM

To: Chang, Andy

Subject: FW: Wind Data for Drake by Sierra Club

To try and push your awaiting inbox above 1,000 – I uploaded the original attachments from this email to the R8 

outgoing solicitation box on OneDrive. 

Hope you had a nice trip, and one free from sulfur dioxide. 

Adam Clark 

Air Quality Planning Unit 

US EPA Region 8 

Denver, CO 

(303)312-7104

From: leslie@weise.us [mailto:leslie@weise.us] 

Sent: Monday, February 08, 2016 10:54 AM 

To: Clark, Adam <Clark.Adam@epa.gov> 

Cc: Jim Riggins <rigginsj@att.net>; Travis Ritchie <travis.ritchie@sierraclub.org>; Jane Ard-Smith 

<janeardsmith@comcast.net>; Sandy Vanderstoep <svanderstoep@sustainablecolorado.org>; Nicole Rosa 

<nicki@totalmath.net>; Jacquie Ostrom <jostrom@lindseyfam.net>; Laura Van Der Pol <laura.vanderpol@gmail.com>; 

Sam Masias <sam.masias@gmail.com> 

Subject: Fw: Wind Data for Drake by Sierra Club 

Hi Adam, 

I am forwarding to you some data that the Sierra Club has compiled concerning the wind patterns near the 

Drake Power Plant as compared with the COS Airport. Unlike Jim Riggins' compiled data from weather 

stations even closer to the plant, this data pulls from the weather monitor at the sole SO2 monitor in

Colorado Springs. It has been concluded by the professionals working for the Sierra Club that the differences 

in wind patterns they compiled and attached to this email are not sufficiently meaningful to warrant 

dismissing the use of the airport NWS as representative weather data for Drake. 

And as an update, although Colorado Springs Utilities has been collecting weather data from the new tower 

they installed at Drake last fall, they have not been willing to share any of that with the public yet (despite 

over 3 months of data having already been collected). 

Please let me know if you have any questions or would like more information. Any word on when a draft

decision by EPA for Drake's non-attainment designation will be released? 

Thank you. 

Leslie Weise 

cell: 303.523.0016 

----- Forwarded Message ----- 

From: Travis Ritchie <travis.ritchie@sierraclub.org> 

To: Leslie Weise <leslie@weise.us>; Jim Riggins <rigginsj@att.net> 

Cc: Jane Ard-Smith <janeardsmith@comcast.net> 
2

Sent: Friday, February 5, 2016 10:20 AM 

Subject: Wind Data for Drake

Hi Leslie and Jim, 

I wanted to follow up on our conversation from last week. I'm attaching two comparison wind roses 

that were run in the area. As you can see, there are differences between the two, but they are not 

dramatically different. Also, importantly, the data from Hwy 24 actually shows differences that would 

tend to increase the concentrations of SO2 from Drake. First, note that the Hwy 24 winds are more 

NW than the Airport, which means they are blowing more toward the mountains, which would tend to 

cause the plume to stack-up more. Second, the winds at Hwy 24 are lighter, which would also tend to 

cause higher concentrations of SO2 because the plume would not disperse as quickly. Both of these 

differences tend to suggest that if our modeling based on airport met data is inaccurate, it is 

conservatively inaccurate (i.e. it would show lower concentrations than what we would expect with onsite data). 

Of course, we have always acknowledged that having on-site met data would improve the accuracy 

of the modeling. (More and better data nearly always improves modeling.) However, we cannot wait 

for that better data because all of the information we have indicates that Drake is causing an 

exceedance of the SO2 limits. That means public health risk because parks, schools, homes and 

businesses are sitting in bad air that will make people sick. 

Please feel free to share this email with your contact at EPA or others. 

Travis Ritchie

Staff Attorney

Sierra Club Environmental Law Program 

85 Second Street, 2nd Floor

San Francisco, CA 94105

Phone: (415) 977-5727

travis.ritchie@sierraclub.org