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Owens Lake Dust ID Meeting

Owens Lake Dust ID Meeting

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Owens Lake Dust ID Meeting

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  1. Owens LakeDust ID Meeting November 10, 2005 Bishop, CA Great Basin Unified Air Pollution Control District

  2. Supplemental Control Measure Process - 1 Beginning in 2004 and based on data from July 1, 2002, SIP Exhibit 2 “shall be” used by the APCO to make annual determinations regarding the need for SCAs. Within 30 days of the determination, the APCO provides written notification to the City. City has 60 days to respond in writing by presenting an alternative analysis of the data.

  3. Supplemental Control Measure Process - 2 • “APCO has full and sole discretion to accept, modify, reject or take no action on the City’s alternative analysis.” (APCO has 30 days to do this.) • Unless the APCO takes action to withdraw or modify his original determination, the requirement for BACM to be implemented on new areas “will automatically be triggered.” • City implements dust controls within 2½ years if shallow flooding, otherwise within 4 years.

  4. Analysis of SCA Dust Issues Raised by CH2M Hill The District examined the following: • Model performance for 2002-04 period • Timing and location of construction activities relative to dust events at SCAs • Sand flux trend for 2002-04 • Potential sand flux due to ATVs

  5. District also investigatedCALPUFF model impacts • Performed an episode analysis.

  6. Model PerformanceAnalysis Ken Richmond, Geomatrix Consultants

  7. Construction Activities Construction PeriodDust Control Project Nov 2000 - Nov 2001 NSS Zones 1 & 2 Nov 2001 - Jun 2002 SSS Phase I Sep 2002 - Apr 2003 SSS Phase II Sep 2003 - Sep 2004 Phase III Nov 2004 - Jul 2005 Phase IV

  8. ConstructionPeriodsNSS: 11/00-11/01SSS Ph I: 11/01-6/02SSS Ph II: 9/02-4/03Phase III: 9/03-9/04Phase IV: 11/04-7/05

  9. District Findings on Construction • Dust events at SCAs were not coincident with construction in most cases. • In cases of coincidence, the SCAs were part of a regional dust event. • Field enforcement reports show good compliance with Best Available Control Measures for fugitive dust at construction sites and on the unpaved roads.

  10. Storm-totalSand Flux(g/cm2)February 1-5, 2003Dust Event

  11. Feb 1-5, 2003

  12. Storm-totalSand Flux(g/cm2)March 25-26,2004 Dust Event

  13. Mar 25-26, 2004

  14. Construction Near Siteswith Significant Dust Episodes 3 source areas that were located near Phase III construction activities had their only Lone or Pack violations on 3/25/2004. Analyzed the sand flux to see if construction influenced the trend at each site: • Site 7387: Lone Violator • Site 7454: Lone Violator • Site 7498: Pack Violator

  15. Potential Sand Flux From ATVsand other activities How much sand could a sand catcher catch if ATVs could release sand? Assume: 1.5 km of ATV trails per sq. km, a 1 cm depth of sand is allowed to blow from the tracks in one dust season (max erosion measured in Zone 2), and it’s free to move across the surface for the dust season. Answer: 3 g This is less than the 5 g minimum field weight for collecting a CSC sample.

  16. Sand Flux RoseSite #75642/03-5/04

  17. Results of District’s Investigation of CH2M Hill’s SCA Issues The District staff found: Good Model Performance – Air Science used biased statistics in their Sept 2005 review. Using the 2003 SIP model analysis approach, the Dust ID model performance for the 2002-04 period was good. No Construction Impacts – Areas with significant dust events were Lone Violators when there was no construction near the source area, and/or were part of regional dust events. Insignificant Sand Flux from ATVs – The potential seasonal sand flux due to ATVs is less than the minimum CSC catch of 5 g.

  18. CALPUFF model impact analysis:How did cell #1891 cause violations at receptors west of this site on May 11, 2004?

  19. SCA Selection • Omitted Pack, Fill and Watch episodes from the SCA list. • All required SCAs are Lone Violators. • Included a list of Recommended Control Areas based on significant dust events and proximity to DCAs and SCAs.

  20. Supplemental Control AreasDust ID ModelJuly 2002 – June 2004