Transcript Case Studies

Dust Definition:
Saguaro West Case Study
Julia Lester
ENVIRON International
WRAP DEJF Meeting
November 16, 2005
1
BACKGROUND
• WRAP’s Dust Emissions Joint Forum (DEJF) developed
a draft definition of dust to discriminate between natural
and anthropogenic sources of dust
• WRAP sought a feasibility assessment of draft definition
– Draft Feasibility Assessment Report with Protocol
(May)
– Case studies as examples of Protocol application
– Recommended revisions of the draft dust definition,
if necessary
– Implementation support, as resources permit
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Case Studies
•
•
Several potential case studies identified
Based on latest Causes of Dust results, COHA
analyses, other WRAP programs, 2 case studies
identified through discussion with WRAP staff and
the DEJF:
– Saguaro West (SAWE) in Pima County Arizona
• CoD / CoHA: 123 dust days with soil / coarse
mass significant contributors to 20% worst
visibility days
– Salt Creek Wilderness in New Mexico
• Interaction with the New Mexico SIP Pilot
Project
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Dust Definition Categories
• Feasibility Assessment Proposed 3 Categories
1. Anthropogenic
2. Natural (some sources currently not inventoried)
3. Mixed: Natural sources that can be
anthropogenically influenced
- WRAP interested in partitioning existing dust
emission estimates for this category (natural vs.
anthropogenic)
- Identified data/method resources may be used for
new or revised inventories for some sources
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Feasibility Assessment Protocol
1. Identify the purpose and goals of the analysis
2. Conceptual Model and rank order the dust sources
3.
4.
5.
6.

in the project area by chosen criteria
Identify major Category 3 sources
Identify controls/mitigations, if desired
For major Category 3 contributors, are existing
methods/databases available to characterize,
estimate, and/or partition the emissions?
If not, can the necessary methods/databases be
developed and at what cost?
If the answers to 5 and/or are yes, definition can be
implemented
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Step 1: Saguaro West (SAWE) Study
Purpose and Goals
• Pilot-scale feasibility assessment (conserve
resources for Salt Creek Wilderness assessment)
Item
SAWE Case Study
Full-scale Study
Analysis area
135 to 225 quadrant, 20-km
radius
Full 360 area with 20km or more radius
Resource
identification
As in full study
All
Dust source
identification
Limited
Comprehensive, GIS spatially-resolved,
long-range sources assessed
Dust source
characterization
Identify models / data for most
significant source
Identify models / data for all significant
sources
Ems Inventory
Most significant
All significant sources
Inv. partitioning
Most significant with available
data
All significant Cat. 3 sources
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Step 2: SAWE Study Conceptual Model
• Conceptual Model Elements
– Geographic setting
– PM and visibility setting
• Focus of this study is worst dust days for
visibility impairment
• Latest CoD and CoHA results
– Geological, topical, ecological, and climatological
setting
– Land use setting
– Summary, including significance threshold
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Conceptual Model: CoD Information
Source: CoD Report, DRI
8
Conceptual Model: SAWE CoHA Information
Source: CoHA Report, DRI
9
Conceptual Model: Land Use
Source: CoHA Report, DRI
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Conceptual Model: Land Use
• Focus area dominated by open shrub/grass lands, with
small areas of agricultural row crops and urban uses
(Mining activities, if study area expanded)
• Potential grazing areas not yet identified
Agricultural crops 5 to 10 km SW of Saguaro West
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Conceptual Model: Summary
• Based on the latest CoD results, case
study will focus on worst dust days
related to local dust sources
– 135 to 225 quadrant focus, radius 20 km (local
sources)
– April through July have greater CM and fine
soil contributions, so seasonal emissions will
be reported if they exist
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Step 2 (cont): Initial Ranking of Sources
Table 1. Dust sources likely to affect SAWE
Dust Source Type
 Description
Agriculture
Crops
Livestock-grazed Rangeland
Construction and demolition
Residential area and
developments
Category
Relevance
(1-5, 1 being
most relevant)
Notes
1
2
~10-km2 area of cropland 510 km SW of Saguaro West
4
Various scatted residential /
light industrial development
in SE area of Focus Area
Identifying data resources
(e.g. 50-m wide irrigation
canal running NW to SE
from 0.5 km S of SAWE
1
Paved and unpaved roadways,
including irrigation canal roads
1
3
Foot trails
Hiking trail system
1
5
Surface mining disturbance:
4 quarries, large copper mine
SE of SAWE
1
4 (or 2*)
35 to 50 km away
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Step 2: Initial Ranking of Sources (cont.)
Table 1 continued. Dust sources likely to affect SAWE
Category
Relevance
(1-5, 1 being
most relevant)
Notes
Natural landslides and rockslides
2
5
Landslide incidence low
(< 1.5% of area)
Extraterrestrial material and impacts
2
5
3
Unknown at this
time
All areas except urban
areas suitable for
wildlife
3
Unknown, but
may be
significant
All areas except urban
areas suitable for
wildlife
Dust Source Type
 Description
Wildlife movement
 Large mammals (cows, sheep,
mule deer, white-tailed deer,
pronghorn, peccary)
Animal burrowing
 12 species of carnivores (e.g.,
coyotes, foxes, bobcats), 3
species of insectivores (shrews),
4 species of lagomorphs (rabbits),
32 species of rodents (gophers,
rats, mice, etc.)
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Step 2: Initial Ranking of Sources (cont.)
Table 1 continued. Dust sources likely to affect Saguaro National Park.
Dust Source Type
 Description
Category
Relevance
(1-5, 1 being
most relevant)
Notes
Windblown from undeveloped lands
(undisturbed or previously disturbed)
3
1
Emission from shrub
lands probably the
highest – need to
identify past and current
rangelands, if any
Areas burned by fires
3
5
Reviewing Fire Forum
resources
Exposed beds of dry riverbeds and
drainages
Brawley Wash and tributaries
Santa Cruz River and tributaries
3
4
Limited amount of
surface water may be
diverted for
anthropogenic use.
Intermittent drainages.
Focus Area is covered
in small dry intermittent
drainages.
Windblown PM from sources created
by natural events over 12 months
previously
3
5
Reviewing Arizona
NEAPs
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Step 2/3: Initial Ranking Summary
• Most relevant: Windblown dust (Category 3)
• Next most relevant: Agriculture (Category 1)
– If the study area was extended to 50 km, surface
mining would also be included at this level
• Emissions from animal movement and
burrowing, or the effects of these activities on
windblown dust emissions, (Category 3)
– relevance cannot be assessed without further
investigation
• Results of Step 5 may indicate the need to reorder the source rankings
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Step 5: Resource Availability for
Category 3 Sources
• For major Category 3 contributors, are
resources available to characterize, estimate,
and/or partition the emissions?
– Data and Model Resource Identification
– Dust source characterization
– Site-specific dust emission estimates
– Emission partitioning
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Step 5: Resource Identification
• 32 data/model resources identified for study area
(many are in the process of development or revision)
Southwest Regional GAP Analysis Project
Attribution of Haze (AoH) data and analyses:
www.wrapair.org/forums/aoh/ars1/report.html
Google Earth (aerials)
WRAP Technical Support Syatem (under development)
www.wrapair.org/forums/aoh/TSS/index.html
National Resources Inventory
WRAP Windblown Dust Emission Model
Land Condition Index
NRCS PLANTS Database
Soil Data Mart: Soil Survey Geographic
(SSURGO) database
Wildlife Exposure Factors Handbook
COHA data: www.coha.dri.edu/
Smithsonian National Museum North American Mammals
Database
Arizona Meteorological Network (AZMET)
Grazing Land Applications Software (GLA)
Hydrometeorological Networks in the
United States (JOSS)
Cumulative Index for the Mammalian Species
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Step 5: Dust Source Characterization,
Emission Estimation, and Partitioning
• Most significant SAWE source (windblown dust)
resource analysis
Source
Category
Availability of
Emissions Data
Availability of Partitioning
Data
Windblown
Dust from
Row Crops
(Category 1)
High: Generate via
WRAP Windblown Dust
Emission Model
Not required for Category 1
Dust Source
Windblown
Dust from
Shrublands
and
Grasslands
(Category 3)
High: Generate via
WRAP Windblown Dust
Emission Model
Data on vegetation coverage
may be available. Vegetation
coverage in grazed areas or
otherwise humanly disturbed
areas could be compared with
vegetation coverage in nearby
ungrazed reference areas
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Step 5: Dust Source Characterization,
Emission Estimation, and Partitioning
• Potentially major SAWE source (animal movement,
impact of burrowing animals) resource analysis
Source
Category
Availability of
Emissions Data
Availability of Partitioning
Data
Large
mammal
movements
(Category 3)
Not available
Identification of legal grazing
lands may be possible
Burrowing
Animal
Impacts
(Category 3)
Direct or indirect
emissions estimates are
not available
Soil disturbance by pocket
gophers is a major source of
natural sediment transport and
disturbance.
Reference area may have
higher emissions than currently
estimated
Emissions may be higher
than assumed through
traditional erodibility
metrics (see next column)
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Step 5: Emission Estimates
• Windblown Dust
– Current windblown dust model estimates
– Spatially and temporally-resolved
• Specific windblown sources considered:
– Agricultural lands
– Grasslands
– Shrublands
– Barren lands
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Agricultural Emissions
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Grasslands
23
Shrublands
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Barren Lands
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Step 5: Emission Summary
• Shrublands dominant
– Grasslands contribute with a significantly lesser
contribution from barren lands
• Agricultural sources in study area appear not to be
inventoried
• Based on current inventory evaluation for nonwindblown sources in Pima County:
– Ag tilling and mining operations ~ 500 tpy PM10
each
– Unpaved roads contribute ~4500 tpy; prevalence in
study area unknown but considered low
• Animal movement, burrowing emissions unknown
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Step 5: Category 3 Partitioning
• For windblown dust from shrublands, are
there areas that are anthropogenically
disturbed or impacted?
– Reviewing grazing databases
– Searching for unpaved road databases
• If anthropogenic influences identified,
partition based on:
– Level 1: areal extent
– Level 2: comparison to reference natural area
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Next Steps
• Study area finalization
• Resolve inventory discrepancies
• Attempt to assess potential relevance of
animal-related emissions or impacts
• Partition scrubland emissions
• Assess dust definition feasibility
• Finalize draft SAWE Case Study report by
end of year
• Begin Salt Creek Wilderness Case Study
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