HomeMy WebLinkAbout07/17/1990, 4 - EARLY GRADING PERMIT AUTHORIZATION - REQUEST TO STOCKPILE AND TREAT SOILS CONTAMINATED WITH PETROLE MEETING DATE:
������►�►►i(�IIIIIIIIIP►►► ��IIIU city of San Luis OBlspo 7-/?- o
COUNCIL AGENDA REPORT ITEM NUMBER:
0
FROM: Arnold B. Jonas Community Development Director;
BY: Pam Ricci., Associate Planner}'
SUBJECT:
Early Grading Permit Authorization —Request to stockpile and treat
soils contaminated with petroleum fuel oil on property located
within the Southern Pacific Railroad right-of-way, adjacent to the
site of the proposed condominium project known as Fairview Station
(2225 Bushnell Street) .
CAO RECOMMENDATION:
Adopt a resolution authorizing stockpiling based on findings and
subject to conditions.
BACKGROUND
Situation
The applicants want City Council authorization to stockpile and
treat contaminated soils excavated from the site of the proposed
Fairview Station condominiums in the adjacent railroad right-of-
way. The Fairview Station site was used as a railroad refueling
facility up until the 1950s. Because of this known past use of the
site, there was a strong possibility that either the soil or
groundwater had been contaminated with petroleum hydrocarbons from
fuel oils stored there. For this reason, the .City requested that
a environmental site assessment and a site remediation work plan
be submitted and approved along with plans for the proposed
condominium project.
Contaminated soils were excavated from the Fairview Station site
between May 29, 1990 and June 11, 1990. The quantity of
contaminated soils found on the site (5600 cubic yards) was much
greater than the originally projected quantity included in earlier
reports (1900 cubic yards) .
The original site remediation work plan, presented to the Planning
Commission and City Council with consideration of the tract map for
the Fairview Station project in October and November of 1989,
indicated that all contaminated soils would be removed from the
site and transported to an appropriate disposal site. Contaminated
soils were defined as those soils with petroleum hydrocarbon
concentrations in excess of 100 mg/kg (above defined City action
levels) . During plan check of the project, this remediation plan
was revised several times. The last plan reviewed by staff
estimated that there was approximately 1,900 cubic yards of
contaminated soil existing on the site. That plan indicated that
400 cubic yards of soil would be treated on site and the remaining
1,500 cubic yards would be transported to a location within the
County for treatment.
�,���,►�u��iIIfIIIIIIn ��I�N city of San Luis OBIspo
COUNCIL AGENDA REPORT
Stockpiling Permit
Page 2
Contaminated soils have been removed from the site of the proposed
condominiums and are being stored on property directly to the north
of the site, also owned by the applicants, and within the adjacent
railroad right-of.-way. Rather than hauling the contaminated soils
to an approved disposal site, the applicants would like to
stockpile the soils in the railroad right-of-way and treat them
there through the clean-up process known as bioremediation.
Significant Impacts
If the request is not approved, the contaminated soils will need
to be hauled away to an approved disposal site. Residents in the
adjoining neighborhood will notice increased noise and traffic from
trucks hauling away the soil. Because of the large quantity of
contaminated soils, it would require approximately 300 truckloads
to haul away the soils.
With approval of the request, staff is suggesting conditions to
limit impacts to the neighborhood including dust control, site
restoration and fencing around stockpiles.
Data Summary
Address: 2225 Bushnell Street
Applicants: The Petra Group, Inc.
Representatives: Bruce. Houseman and Keith Gurnee
Zoning: R-2-S
General Plan: Medium Density Residential
Environmental Status: Categorically exempt under Class 4, Minor
Alterations to Land, Section 15304. of
CEQA Guidelines
DISCUSSION
1. Volume of Contaminated Soils
The primary reason that this matter is before the council is that
the volume of contaminated soils actually excavated from the site.
(5600 cubic yards) was so much greater than originally estimated
quantities (1900 cubic yards) . Projecting the extent of soil
contamination prior to actual excavation is difficult because the
variations within the soil stratigraphy that determine how
contaminants will spread cannot be seen from the surface. Until
the excavation process is actually underway, there is no foolproof
method to projecting the quantity and the extent of contaminated
soils.
-2
��� ��Hi�HIIIIIIiPnN�gIUIN City of San LUIS OBISPO
COUNCIL AGENDA REPORT
Stockpiling Permit
Page 3
With this particular site, significantly more contaminated soil was
found under an excavated retaining wall than expected, and
contaminated soils were inadvertently mixed together with clean
uncompacted fill deposited above them during excavation.
Because of this dramatic difference between actual and projected
quantities of contaminated soils, the applicants were forced to
consider alternatives to hauling away all of the contaminated
soils. The impacts associated with hauling the existing volume of
contaminated soil include the greatly escalated cost to the
applicants, the noise and added traffic to the neighborhood, and
the environmental implications associated with dumping the soils
at another site without removing the contaminants.
2. Proposed Bioremediation Treatment Process
The applicants want to treat all 5600 cubic yards of contaminated
soils excavated from the site in the adjacent railroad right-of-
way through the process of bioremediation. Bioremediation is a
process where soils are isolated and injected with special bacteria
that break down and digest contaminants in the soil, degrading the
oil into nonhazardous natural byproducts. The soils are monitored
until target concentrations are maintained. once these target
concentrations are achieved, • the soils can be reused, usually under
roadways and in driveway and parking lot areas. A more detailed
description of the bioremediation process is discussed in the
attached Earth Systems work plan report.
Bioremediation is considered the environmentally preferred
alternative because the process eliminates the contaminants
existing in the soil rather than simply transporting the
contaminated soils from one location to another.
Figure 1 of the attached Earth Systems report shows the proposed
treatment area for contaminated soils in the railroad right-of-
way. Contaminated soils will be laid out on black polyethylene
sheeting to prevent contact with underlying soils. The soils will
be piled to a height of about 18 inches and covered with the same
polyethylene sheeting. Stockpiles will be enclosed with cyclone
fencing. A condition of recommended approval calls for wood slats
to be installed in fencing to further screen stockpiles. Openings
between stockpiles allow for continued pedestrian access through
the area.
•3
city O� San tins OBISPO
Worms COUNCIL AGENDA REPORT
Stockpiling Permit
Page 4
All contaminated soils are proposed to be treated in the railroad
right-of-way. In staff's opinion, the railroad right-of-way is the
best location for treatment since it is farther away from
residences, less visible because of its lower elevation and will
not interfere with other on-going uses in the vicinity. Soils
currently stockpiled on other property owned by the applicants at
2120 Florence Avenue, directly north of the Fairview Station site,
will also be moved to the railroad right-of-way because the right-
of-way is a preferred treatment location for the reasons previously
noted.
The revised remedial work plan submitted estimates that treatment
will take about six months. Staff is recommending as a condition
of approval that the stockpiling of contaminated soils be
authorized for a year, with the possibility of one 6-month
extension being authorized administratively.
The applicants have indicated that they would like to use the
stockpiled soil once treated as fill material on property they own
immediately to the north and the south of the Fairview Station
site. While hazardous compounds are essentially removed through
the bioremediation treatment process, some traces of contaminants
may remain in heavier clay soils. Therefore, staff may have
concerns with treated soils being reused as fill material in
projects designed for residential occupancy.
As previously mentioned, treated soils are most commonly used in
driveway and parking lot areas. Since it is unlikely that 5600
cubic yards of soil will be used for such improvements in the
immediate vicinity of the site where soils are now stored, it will
probably be necessary to transport treated soils to one or more
locations for reuse. In any case, staff would need more
information from the applicants' soils engineer on contaminant
levels in the soil after treatment before making any specific
recommendations regarding their use.
The applicants are also aware that using the treated soils on
either of the sites they own in the vicinity prior to approval of
project development plans would again require council approval of
an early grading permit.
3. Dust Management Plan
The Community Development and Fire Departments have received
several complaints from neighbors regarding dust generated with
earth-moving activities on the Fairview Station site. Staff
required that the applicant submit a dust management plan outlining
measures to be taken during all phases of project construction to
limit dust generation. /fit_
city of san tuis oBispo
a COUNCIL AGENDA REPORT
Stockpiling Permit
Page 5
The applicants' dust management plan is attached. A slightly
revised version of that plan has been incorporated into conditions
in the attached resolution supporting approval of the stockpiling
permit. If followed, measures included in the plan should keep
dust levels associated with construction activities to a minimum.
CONCURRENCES
The Fire Department has reviewed this report and concurred with the
staff recommendation.
ALTERNATIVES
1. The Council may adopt Resolution No. 2 which would deny the
request and require that all contaminated soils be removed and
transported to an approved disposal site.
Staff is concerned with the amount of noise and truck traffic
associated with this alternative. If this alternative is
adopted, a condition is recommended that a plan for removing
-- soils be submitted to and approved by the Community
Development and Fire Departments so that the amount of truck
traffic through the neighborhood can be monitored.
2. The Council may continue review with direction to the
appellants and staff.
This alternative would be appropriate if the council feels
there is additional information needed, or if they would like
to see changes made in plans, prior to rendering a decision.
RECOMMENDATION
Staff recommends that the City Council authorize issuance of the
requested stockpiling permit, based on the findings and subject to
the conditions contained in the attached resolution.
Attachments: Draft Resolutions
Figure 1 - Proposed treatment area and vicinity
Earth Systems Revised Remedial Action Plan
Dust Management .Plan
d:soils.wp
RESOLUTION NO. (1990 Series)
A RESOLUTION OF THE COUNCIL OF THE CITY OF SAN LUIS
OBISPO AUTHORIZING ISSUANCE OF A GRADING PERMIT TO
ALLOW STOCKPILING ON A SITE LOCATED WITHIN THE SOUTHERN
PACIFIC RAILROAD RIGHT-OF-WAY ADJACENT TO THE SITE OF
THE FAIRVIEW STATION CONDOMINIUMS AT 2225 BUSHNELL
STREET
WHEREAS, the City Council received a request for a
stockpiling grading permit for property located within the
Southern Pacific Railroad right-of-way adjacent to the site of
the Fairview Station Condominiums at 2225 Bushnell Street; and
WHEREAS, the council has considered the reports of
staff, public testimony, and materials submitted by the
applicant; and
WHEREAS, the potential environmental impacts of the
project have been evaluated in accordance with the California
Environmental Quality Act and the city' s Environmental Impact
Procedures and Guidelines.
NOW, THEREFORE, the council resolves to authorize
issuance of a grading permit as follows:
SECTION 1. Findings. This council finds:
1. The proposed grading operation will not adversely affect the
health, safety and welfare of . persons residing or working on
the site or in the vicinity, '.
2 . The proposed grading operation is consistent with the city's
grading ordinance.
3 . The proposed grading operation is exempt from environmental
review.
SECTION 2. Conditions:
1. The early grading authorizing stockpiling located on a site
O within the Southern Pacific Railroad right-of-way adjacent
to the site of the Fairview Station Condominiums at 2225
Bushnell Street shall be valid for a period of one year from
n -
Resolution No. (1990 Series)
Grading Permit J
Page 2
the date of permit issuance from the Building Division. One
time extension of the permit, not to exceed a period of six
months, may be requested in writing prior to expiration of
the permit to the approval of the Community Development
Director. The applicant's written request needs to document
any extenuating circumstances that would warrant an
extension.
2 . The applicants shall submit an application and appropriate
plans for a grading period as outlined in Section 15.44. 16
of the Municipal Code (Grading Ordinance) . Stockpiling of
contaminated soils shall be completed as outlined in the
Earth Systems remedial work plan dated June 29 , 1990.
3 . The applicants shall deposit a cash surety guaranteeing
proper maintenance of stockpiles and restoration of the
property to its present condition as required by the
Community Development Department.
4 . Consistent with Section 15.44 .270, all graded surfaces shall
be wetted, protected or contained in such a manner as to
prevent dust or spill upon any adjoining property gr street.
The following measures shall constitute the Fairview
Station dust_management plan and shall remain in effect
during all phases of that project's construction and during
the time that contaminated soils are stockpiled and treated
within the Southern Pacific Railroad right-of—way:
a. Regular wetting of roads and graded areas (at least
twice daily with complete coverage of all active
areas) ;
b. Increasing frequency of watering whenever winds exceed
15 mph;
C. Cessation ofgrading actvities during periods of high
winds over 25 mph;
d. Direct application of water on material being excavated
and/or transported onsite or offsite;.
e. Watering material stockpiles; and
f. Periodic washdowns, or mechanical streetsweeping, of
Florence Avenue .and Bushnell and. Bishop Streets in the
vicinity of the construction site.
Resolution No. (1990 , Series)
Grading Permit
Page 3 .
5. The applicants shall install wood slates in cyclone fencing
around stockpiles to the satisfaction of the Community
Development Department.
On motion of
seconded by and on the
following roll call vote:
AYES:
NOES:
ABSENT:
the foregoing resolution was passed and adopted this day
of , 1990.
Mayor
ATTEST:
City Clerk
APPROVED:
it A inistrative Officer
-
t n
l
Community Devel p ent Director
RESOLUTION NO. (1990 Series)
A RESOLUTION OF THE COUNCIL OF THE CITY OF SAN LUIS
OBISPO DENYING ISSUANCE OF A GRADING PERMIT TO ALLOW
STOCKPILING ON A SITE LOCATED WITHIN THE SOUTHERN
PACIFIC RAILROAD RIGHT-OF-WAY ADJACENT TO THE SITE OF
THE FAIRVIEW STATION CONDOMINIUMS AT 2225 BUSHNELL
STREET
WHEREAS, the City Council received. a request for a
stockpiling grading permit for property located within the
Southern Pacific Railroad right-of-way adjacent to the site of
the Fairview Station Condominiums at 2225 Bushnell Street; and
WHEREAS, the council has considered the reports of
staff, public testimony, and materials submitted by the
applicant; and
WHEREAS, the potential environmental impacts of the
project have been evaluated in accordance with the California
Environmental Quality Act and the city's Environmental Impact
Procedures and Guidelines. O
NOW, THEREFORE, the council resolves to deny issuance
of a grading permit as follows:
SECTION 1. Findings. This council finds:
1. The proposed grading operation will adversely affect the
health, safety and welfare of persons residing or working on
-the site or in the vicinity.
2 . The proposed grading operation is inconsistent with the
city's grading ordinance..
SECTION 2 . Within thirty days of this resolution, the
applicants shall submit a plan for removing contaminated soils to
the Community Development and Fire Departments for review and
approval. The plan shall specifically state the number of truck
trips per day needed to haul soils away and include a timeframe
for completion.
On motion of
�- 9
i
O Resolution No. (1990 Series)
Grading Permit
Page 2
seconded by and on the
following roll call vote:
AYES:
NOES:
ABSENT:
the foregoing resolution was passed and adopted this day
of 1990.
Mayor
ATTEST:
City Clerk
APPROVED:
City F,dm'nistrative Officer
i It rn
ox -
Community Dev pment Director .
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Earth Systems Environmental , Inc.
C' A 6emCer of The Eartn Systems Group
170-A Granada Drive - San Luis Obispo. CA 93401 • (805) 541-5983 FAX (805) 544-0531
June 29, 1990 Job No. ES-0109-PG3
Doc No. 9006-E083.WKP
San Luis Obispo City Fire Department
748 Pismo Street
San Luis Obispo, California 93401
Attention: Mr. .Mike Smith, Hazardous Materials Inspector
Subject: Revised Remedial Action Plan
Fairview Station Project--PETRA Enterprises
Southwest Comer of Florence Avenue and Bushnell Street
San Luis Obispo, California
Gentlemen:
At the request of PETRA Enterprises personnel, this letter presents a summary
of activities conducted to date at the above referenced site; and provides a proposed
work plan describing remedial action planned for contaminated soils removed from
the site. In addition, the letter provides additional information regarding the
proposed remediation plan which was requested by Mr. Michael Smith of the San Luis
Obispo Fire Department and Ms. Pam Ricci of the City Planning Department. This
work plan supersedes our earlier work plans dated June 20 and April 20, 1990 and the
follow-up letters dated May 11 and May 18, 1990.
Project Summary
Excavation of Contaminated Soils
Removal of contaminated, soils was begun on May 29. 1990 by the R. Burke
Corporation of San Luis Obispo and completed on June 11, 1990. Excavation was
accomplished using conventional earth-moving equipment, under the observation
and testing of Earth Systems Environmental field personnel. As excavation
progressed, analytical testing was conducted on-site, using a State-certified mobile
laboratory, to verify that contaminants in remaining soils were below San Luis
Obispo City Fire Department (SLOFD) action levels. After obtaining analytical results
from the boundaries and bottom of the excavation showing that soils with TPH
concentrations greater than 100 mg/kg had been removed in accordance with SLOFD
requirements, the resultant excavation was partially backfilled and compacted in
accordance with City of San Luis Obispo requirements .for fill placement. Pursuant to
SLO Fire Department 2 June 29, 1990
the June 12, 1990 meeting attended by Bruce Houseman of PETRA Enterprises, Irwin
Willis and Mike Smith of the City Fire Department, Tom Baasch and Bob Bishop of the
City Engineering Department, and Pam Ricci of the City Planning Department, it was
agreed that removal of contaminated soil from the Fairview Station project site has
been completed to the City's requirements. Test results from samples taken during
excavation indicate that soils remaining on the site do not contain hydrocarbon
concentrations greater than 100 milligrams per kilogram (mg/kg), as required by
the City Fire Department. Compaction testing of the fill was provided by the project
Soil Engineer, Pacific Geoscience, Inc. A report showing the limits of excavated
areas, sampling locations and analytical results is currently being prepared, and will
be forwarded to the Fire Department upon completion.
The volume of contaminated soil .removed from the site is approximately 5,600
cubic yards, which is more than was originally anticipated. The reasons for the
larger-than-expected volume of soil are:
• The area below the concrete retaining wall along the west
property line, where earlier subsurface exploration was hindered by
the presence of debris and trees, contained significantly more oil
contamination than was expected.
• The presence of approximately 15 feet of uncontaminated fill
overlying contaminated soils, which resulted in significant
amounts of clean soils being inadvertently mixed in with the
contaminated soils during removal. The mixing of these soils was
unavoidable given the site conditions, and probably added 10% to
15% to the total volume of soils stockpiled on-site.
Bioremediation Procedures
As outlined in the April 20, 1990 work plan and follow-up letters dated May 12
and May 18, 1990, it was proposed to treat the contaminated soils, using biological
(bacterial application) methods, on two adjacent parcels owned by PETRA Enterprises.
Verbal approval for this work plan was received from both the City Fire and
Community Development Departments at a site meeting on April 23. Subsequently, it
9006-E083.WKP ES-0109-PG3
d-��
SLO Fire Department 3 June 29, 1990
G �
was determined by the City and conveyed to PETRA Enterprises at the June 12 meeting
that stockpile approval would need to be obtained from the San Luis Obispo City
Council prior to allowing any further work on the project to proceed. Work on
backfilling the excavation was halted by the City at that time, and no grading or
remedial work has been performed since then.
It is our understanding; that PETRA Enterprises has obtained an agreemcnt
with the Southern Pacific Railroad Company (SPRR) for the use of the SPRR
easement, to the west of the Fairview Station site, as a treatment area for the
contaminated soils. The proposed area that will be used to spread the soils -for
treatment is shown on Figure 1, attached with this report. The soil stockpile that
presently occupies the vacant lot at the northeast comer of Florence Avenue and
Rachel Street is proposed to be relocated to the right-of-way, in order to consolidate
the treatment area. Use of the SPRR right-of-way possesses several advantages over
the use of the PETRA properties as a treatment area, such as:
C
• The area available on the SPRR right-of-way is larger than the
available PETRA properties, and will better accommodate the volume of
soil that has been excavated.
• The SPRR area is further from adjacent residential areas, and
should present less of a visual impact to the surrounding area.
• The cost for off-site disposal of the volume of soil excavated from
the site would be in excess of $800,000.00. Besides being
environmentally undesirable to simply transfer the
contamination to another location, it would be impractical to
implement such a remedial action, because of the insurmountable
financial burden it would present to the property owner.
Bioremediation of soils is preferable to off-site disposal, because the process
destroys the contaminant in the soil, rather than simply moving the contaminant
from one location to another. Another advantage of this technology is that future
9006-E083.WKP ES-0109-PG3
SLO Fire Department 4 June 29, 1990
_k
Are
liability for the generator is reduced, because the offending compounds are
essentially removed once treatment is complete.
The bioremediation process will involve the addition of microbes and nutrient-
enriched water to contaminated soils. Currently, contaminated soil from the site has
been placed on 10-mil polyethylene sheeting to prevent the contact of contaminated
soils with underlying soils. A low earthen berm has been constructed around the
perimeter of the piles, to prevent runoff from the piles onto the surrounding area ,
and vice-versa, in the event of rain. A chain link fence has been placed around the
stockpile to restrict unauthorized access. to the treatment area. Pursuant to a re(fuest
from the City, this fence will be provided with privacy slats to reduce the effects of
wind on the plastic sheeting covering the piles, and to minimize visual impact to the
surrounding area. If necessary, an open path between the piles can be provided to
maintain pedestrian access across the railroad right-of-way. A description of the
actual treatment process is provided below. -
Specific quantities of nutrients will be added to the soils, along with a cultured
strain of microbes and water. Debris (e.g. concrete, steel piping) not considered
suitable for cultivation in the bioremediation pile will be segregated, and disposed of
appropriately. Approximately 65 pounds of 15-15-15 fertilizer per 100 cubic yards of
soil will be added to furnish an appropriate mixture of nutrients for bacterial
growth. The fertilizer will be added as a liquid mixture to the piles. In addition, water
will be added at a rate of approximately 3 to 5 gallons per cubic yard of soil. The
water used in the treatment process will be reclaimed water obtained from the City
wastewater treatment plant on Prado Road.
After the fertilizer and water have been added, an appropriate quantity of
Solmar Corporation Formulation L-104 cultured bacteria will be added to the prepared
soil, cultivated and covered. The microbe culture proposed for use on this project is
formulated to metabolize heavy, tarry types of oils, as well as aromatic hydrocarbons.
It is composed of naturally occurring bacteria, which have been selectivcly
concentrated on the basis of their ability to metabolize the types of contaminants
known to exist in soils at the site.
The by-products of biologic degradation of the hydrocarbons should consist
primarily of carbon dioxide (CO2) and water. The treatment piles will be covered with
polyethylene sheeting to prevent soil aeration, as well as to maintain soil moisture
9006-E083.WKP ES=0109-PG3
SLO Fire Department 5 June 29, 1990
C
MR
conditions. If necessary, moisture conditioning and maintenance of microbe
populations in the treatment stockpiles will be performed periodically through
application of additional soil nutrients and water.
The time frame for completion of the project cannot be stated with certainty,
due to various factors which affect the rate of the bioremediation process, such as
ambient temperature. contaminant concentrations, nutrient levels; and soil type
variations. We expect that the time necessary to reduce contaminant concentrations
to levels that will be acceptable to regulatory agencies to be on the order of six.
months from the beginningof treatment; however, this period could be shorter- or
longer depending on the above variables. A more accurate time frame may be
possible once the treatment is underway, and the rate of contaminant degradation
can be evaluated.
Soil Sam Mit g Procedures
Soil sampling from both the excavation and stockpiles will be accomplished by
grab sampling, or with a two-inch diameter hand sampler equipped with stainless
steel liners for soil retention. Soil samples will be placed in stainless steel sleeves,
sealed with Teflon. film, capped, and placed in plastic bags, and chilled for transport
to a California certified laboratory, observing chain-of-custody procedures. All
sampling equipment will be cleansed with tri-sodium phosphate (TSP) and rinsed
with de-ionized water prior to sampling, and between sample intervals, to minimize
the possibility of cross-contamination.
Laboratory Analysis of Soil Sam lames
After construction of the treatment piles, soil samples will be analyzed at a
State-certified analytical laboratory. Samples will be analyzed for TPH by U.S.
Environmental Protection Agency (EPA) methods 8015 and 418.1.
Sampling Schedule
After construction of the bioremediation stockpile, progress of the treatment
will be monitored by a geologist or engineer using a photo-ionization detector (PID).
We plan to collect and analyze soil samples to evaluate the progress of the treatment
process approximately four times during the course .of treatment.
9006-E083.WKP ES-0109-PG3
SLO Fire Department 6 June 29, 1990
ME 0 OF
When it appears that total petroleum hydrocarbon concentrations have been
reduced to below the SLOFD action level of 100 mg/kg, samples will be collected for
analysis in the presence of SLOFD personnel to verify that contaminant
concentrations have indeed been reduced to acceptable levels.
Report Preparation
A staff engineer/geologist will prepare a report documenting the results of
soil treatment, which will be forwarded to the SLOFD. The final report will include a
summary of excavation and treatment activities, copies of any required' permits, a -site
map showing soil - sample locations, laboratory reports, and chain-of-custody
documents. The report will be signed by a California Registered Geologist. A request
will be made to the City Fre Department for closure of the case at that time;
In conclusion, we feel that this revised remediation plan is preferable over
the original plan to dispose of contaminated soils at a Class I landfill in that 1) )
contaminated soils will still be removed from the proposed building area, which is
consistent with the desire expressed by the City, and 2) the soil contaminants will be
destroyed, rather than merely shifting the problem from one location to another.
The issue of dust entering the surrounding neighborhood, a concern which
has been raised by residents in the area, should be effectively mitigated by the fact
that the treated soils will need to bekept in a very moist condition to permit bacterial
growth to occur, and that the piles will be covered with plastic sheeting to maintain
this moisture content; thus, the generation of dust from the piles during the
treatment procedure should not be a problem. As observed by both site workers and
City personnel during the removal process, the contaminated soils are already in a
naturally moist and generally non dust-producing condition. In our opinion, the
off-site dust migration that has been experienced at the project site is more associated
with site grading activities and backfilling of the excavation from which the
contaminated soil was removed, rather than a direct effect of contaminated soil
removal.
We hope the preceding will prove sufficient for your Department's review of
this remedial action plan. Should you or other City staff have any questions or
9006-E083.WKP ES-0109-PG3 �_/�
SLO Fire Department 7 June 29, 1990
comments regarding this, work plan, or the project in general, please contact this
office at your convenience.
Sincerely,
EARTH SYSTEMS ENVIRONMENTAL, INS.
Tim Conroy, nR1481
Project Geologist
Distribution: Mike Smith, SLO Fire Department
C'I Tom Baasch, SLO Engineering Department
Pam Ricci, SLO Planning Department
Bruce Houseman, PETRA Enterprises
9006-E083.WKP ES-0109-PG3
�1
ONE
■ ® O A Real Estate Development Company
T H E P.O. Box 3602,San Luis Obispo CA 934,,,'
P E T R A (805) 542-04.94
GROUP,
INC.
June 18, 1990
FAIRVIEW STATION
TRACT 1827
SAN LUIS OBISPO, CA
RE: DUST MANAGEMENT DURING GRADING OPERATIONS
The following measures are recommended for dust management during
the grading operation for the above referenced Tract:
1. Regular wetting of roads and graded areas (at least twice daily
with complete coverage of all active areas) .
2. Increasing frequency of watering whenever winds exceed* 15 mph.
3 . Cessation of grading activities during periods of high winds
(i.e. , over 30 mph. )
i'
4 . Direct application of water on material being excavated and/or
transported on-site or off-site.
5. Watering material stockpiles.
6. Periodic wash-downs of public streets in the vicinity of all
entrances to construction sites.