HomeMy WebLinkAboutAgenda - 11-03-2004-9cORANGE COUNTY
BOARD OF COUNTY COMMISSIONERS
ACTION AGENDA ITEM ABSTRACT
Meeting Date: November 3, 2004
Action Age a
Item No. -- C,.
SUBJECT• Fairview Master Plan Memorandum of Agreement and Status Report
DEPARTMENT: County Attorney, County
Manager, ERCD, Recreation
and Parks
PUBLIC HEARING: (Y/N) No
ATTACHMENT(S):
1) Draft Fairview Park MOA
2) Draft Preliminary Concept Plan
3) Map of Site -Park and Operation Center
4) 9/30/04 County Engineer Memo re Cost of
Restoring Landfilled Areas of Park
INFORMATION CONTACT:
Geof Gledhill, 732-2196
Gwen Harvey, 245-2300
David Stancil, 245-2590
Lori Taft, 245-2660
TELEPHONE NUMBERS:
Hillsborough 732-8181
Chapel Hill 968-4501
Durham 688-7331
Mebane 336-227-2031
PURPOSE: To review the draft Memorandum of Agreement between the County and Town
of Hillsborough regarding the master planning and design of Fairview Park and associated
land and facilities, and to receive a brief status report on activities toward the park design.
BACKGROUND: At the September 215f meeting, the Board instructed staff to continue to
work on preliminary activities toward the planning and design of Fairview Park, and asked
that the Town and County Attorneys revise the draft Memorandum of Agreement (MOA)
accordingly. The design process for the park would create a Master Plan for the park site
and the adjoining County Public Works property, as agreed by the County and Town boards
in 2003, which includes the proposed site far parks operation base and/storage facility as
well as properties subject to land swap discussions. A "first phase" of Fairview Park exists,
with a playground and ballfield constructed separately in 1986 and 1999. The Master Plan
project is tentatively slated to begin in the early spring of 2005.
The County Attorney, with input from County staff, has revised the draft MOA. A copy of the
draft MOA with those revisions has been provided to the Town attorney for review and
consideration by Hillsborough. The revised draft is attached.
Generally, the revised draft separates out the future operation and maintenance issues for
the park, to be addressed in a subsequent second interlocal agreement between the Town
and County, and focuses instead on the master planning and design for the park and Public
Works property, The revised MOA also notes, while the Master Plan would focus on
potential new facilities for the park, it would also include for the Public Works parcel existing
buildings, general locations of proposed future buildings, including building footprints, and the
location of infrastructure (parking, etc) that would serve the whole site,
In addition to the MOA revisions, Gaunty staff has worked to lay the groundwork for the
design process to begin in March/April of 2005:
On September 215`, the Board authorized staff to solicit proposals for the topographic
and cultural/archaeological surveys of the site that will be needed for the design.
Requests far Qualifications have been sent to prospective firms, and it is anticipated
that contract awards will be ready far the Board's consideration on November 16th,
Given the existence of biological expertise on staff and through the Commission for
the Environment, staff is proposing to do the biological assessment in-house to save
funds far the park project. The survey work should be completed by the end of
March.
2. A draft Preliminary Concept Plan has been prepared for the consideration of the
County and Town boards, as the general framework for the project design,
3. The County Engineer has prepared a memorandum outlining the costs/feasibility of
restoring the landfilled portions of the park site (attached), The draft Preliminary
Concept Plan proposes to focus park activity in areas of the site that were not used
for landfilled materials.
After Board discussion of these items, possible next steps far the project might include
December: Approval of MOA and Preliminary Concept Plan
January: Recn~itment for Master Plan Committee
Febntary: Appointment of Master Plan Committee
Early April: Begin Master Plan process
FINANCIAL IMPACT: There is no cost associated with the consideration of the revised draft
MOA. The 2001 voter approved bonds included $850,000 far development and construction
of Phase Two of Fairview Park, Of the total, $200,000 is available for planning, design and
survey work with the remaining $650,000 for construction and development of the park. Staff
anticipates that the cost of the preliminary survey work for park design (topographic contours
and cultural/archaeological evaluation) will be around $50,000.
In addition, the Board has approved a total of $675,000 for construction of the Parks
Operations Base/County Storage Facility. Funding for this project is available from two-thirds
net debt reduction bonds issued by the County in July 2004,
As noted in the County Engineer's memo, the cost of restoring the former-landfill portions of
the site could be $1.5 million to $12 million, depending on several variables that need further
assessment, A funding source for this restoration has not been identified,
RECOMMENDATION(S): The Manager recommends that the Bcard consider the revised
draft MOA, and provide direction to the County Attorney and staff,
3
Draft 10/27/04
STATE OF NORTH CAROLINA
COUNTY OF ORANGE
MEMORANDUM OF AGREEMENT
TOWN OF HILLSBOROUGH
COUNTY OF ORANGE
REGARDING PLANNING FOR FAIRVIEW PARK, COUNTY
PARKS OPERATIONS BASE AND
TOWN AND COUNTY PUBLIC WORKS FACILITIES
THIS AGREEMENT, made and entered into between the Town of Hillsborough, North
Carolina, a North Carolina municipal corporation, xxx Churton Street, Hillsborough, North
Carolina 27278 (hereinafter referred to as the "Town"), and Orange County, a body politic and
corporate, a political subdivision of the State of North Carolina, 200 South Cameron Street,
Hillsborough, North Cazolina 27278 (hereinafter referred to as the "County"), for the ,joint
development of a park and public facility campus.
WITNESSETH
WHEREAS, the parties to this agreement aze public bodies, politic and corporate, under the laws
of the State of North Carolina; and
WHEREAS, the parties are vested with the power and authority to own and improve real estate
for' recreational and other public purposes; and
WHEREAS, the Fairview azea of Hillsborough has a designated park site (hereafter "the
Fairview park site") that was established as part of the Community Revitalization effort funded
through Community Development block Grants in the 1980s, and identified in both the County
and Town Comprehensive Plans; and
WHEREAS, limited facilities have been constructed at the Fairview pazk site, including a
playground and playing field; and
WHEREAS, the 2001 Park and Open Space Bond for Orange County included $850,000 for
planning and construction of the Fairview park site; and
WHEREAS, the Town and County both own property including and in the immediate vicinity of
the Fairview park site, including the Orange County Public Works facility, totaling 92 acres; and
WHEREAS, the Town and County recognize the mutual benefit and interest of the parties
hereto, and to the public generally, in the construction of park and community facilities on the
4
Draft 10/27/04
Fairview park site and other Town and County owned property in the vicinity of the Fairview
park site; and
WHEREAS, it is recognized by both parties that there are limitations imposed by safety
considerations caused by the Fairview park site's previous use for waste-disposal purposes, as
addressed inpart by a geo-technical report ("Report of Geotechnical Evaluation, Closed
Hillsborough Landfill Site, Tuly 19, 2000") in 1999; and
WHEREAS, the parties recognize the mutual benefit in the County acting as the lead entity in
the construction and financing of facilities at the Fairview park site, to be built with funds from
the 2001 bond amount of $850,000; and
WHEREAS, the laws of the State of North Carolina provide that the parties hereto may contract,
for the ,joint design, construction, development and use of facilities for the stated public
purposes; and
WHEREAS, the parties hereto agree to allow the future construction and use of al] of the three
properties identified on the map in Attaclunent 1 to be developed and programmed far public
activity as one unit meeting mutual needs contingent on future approval of plans for' the
properties; and
WHEREAS, the funding for any additional facilities or activity at the Fairview park site (beyond
the $850,000 currently appropriated by the County for Phase II of the park) will be addressed by
the County and Town in amutually-agreeable fashion at a later date:
NOW, THEREFORE, in consideration of the foregoing and of the mutual promises and
obligations set forth herein, the receipt and sufficiency of which is hereby acknowledged, the
parties agree as follows:
1. PROCESS FOR PLANNING & DESIGN OF PARK, COUNTY PARKS
OPERATIONS BASE AND TOWN AND COUNTY PUBLIC WORKS FACILITIES
The process for planning and designing the Fairview park site, County Parks Operations Base
and Town and County Public Works facilities will encompass the land currently owned by
both the Town and County in the immediate vicinity of the Fairview park site (as shown in
the map in Attaclunent 1), Together these parcels represent approximately 92 acres and are
hereinafter collectively referred to as "the Site." The Planning for the Fairview Park and
County Parks Operations Base will focus on the park, but will also consider and address, to
the extent possible, the interests of both the Town and County to locate additional, facilities
on the property, such as the County Parks Operations Base and Town and County Public
Works facilities.
The County and Town will appoint, as soon as practical, a Master Plan Committee to develop
recommendations for the design and use of the Site. The Committee shall be appointed by
approval of both County and Town Boards of Commissioners, and shall consist of the
following charge and membership:
5
Draft 10/27/04
A. CHARGE to the Master Plan Committee:
Develop a Master Plan for the Site, within the framework of any operating guidelines or
other instructions as offered by the elected Boards, to include the following:
1. A map of the Site with the design for the Fairview Park, including proposed
buildings, playing fields, roads, parking, other facilities, amenities, infrastructure
locations, vegetative cover, hydrology and other components that are commonly
included in a park or public facility concept plan. The map of the Site shall
include existing and planned buildings of the County Parks Operations Base and
the Town and County Public Works facilities. Planning of the County Parks
Operations Base and the Town and County Public Works facilities is limited to
the location of buildings, roads, pazking and other infrastructure.
2. A written report outlining the proposed uses, the design rationale, description of
work group process, natural and cultural features, means of soliciting community
input, the potential future phases, and construction cost estimates. If needed, the
report should also include a phasing plan, showing how the Fairview Pazk and
other public facilities could be developed over time in acost-efficient fashion,
3, The report should address and recognize the limitations imposed by safety
considerations caused by the Fairview park site's previous use for waste-disposal,
as addressed inpart by a geo-technical report prepared in 1999 ("Report of
Geotechnical Evaluation, Closed Hillsborough Landfill Site, July 19, 2000").
Further recommendations maybe needed to address phased remediation of
portions of the Fairview park site..
4, The Master Plan should address co-location of existing and future public facilities
and provide for a synergy and compatibility of uses between park functions and
other public functions wherever possible.
5. The Committee should review the "old" 1988 Fairview Park Concept Plan as part
of the Master Plan and determine its validity, if any.
2. EXPECTATIONS OF MASTER PLAN FINAL PRODUCT /MEMBERSHIP OF
MASTER PLAN COMMITTEE
Product: A Master Plan report and map, as described above.
Timeframe for Product: by Septen:ber•, 100.5
Final Steps: Once completed, the Master Plan will be submitted to both Boards of
Commissioners for approval. The Boards may approve the Plan, remand it back for further
work, identify revisions and alternatives, or decide not to pursue the Master Plan..
Proposed Membership of Master Plan Committee:
6
Draft 10/27/04
- 2 Orange County Commissioners
- 2 Hillsborough Town Commissioners
- 1 member, Hillsborough Parks and Recreation Commission
- 1 member, Orange County Recreation and Parks Advisory Council
- 6 conununity citizens
Staff assistance to the Commmittee would be provided jointly by Orange County m:d the Town
of Hillsbor°ough, including the County and Torn Managers (or their designees), County
Open Space Design Specialist, County Recreation mrd Pm•ks Management Director, County
Environment and Resour°ce Coraervation Director, Town and County Planning Directors,
County and Town Engineers, County Purchasing Director, Courrry and Town Public Works
Directors, arrd other staff members as shall be deemed r:ecessarry.
Operating principles for the Master Plan Committee should include the following:
1, The Committee should review and consider the 1988 Concept Plan and determine its
validity and usefulness
2. The Committee should consider impacts on the County Parks Operations Base and
the Town and County Public Works facilities in developing the Master Plan,
incorporating these facilities into the scheme of the Master Plan as far as practical.
3. The Committee is asked to address and site the following as part of the Master Plan:
- Active and low-impact recreation facilities
- Provision of buffers for adjoining neighborhoods
- Protection of sensitive natural resource lands
- Reflect existing and proposed County Parks Operations Base and Public
Works facilities and the infrastructure necessary for these facilities
4. The Committee should not address the following facilities as part of the Master Plazr:
- Orange County Public Works expansion or a Town of Hillsborough Public
Works facility -beyond the Site infrastructure design and designating the
areas for such activities on the Master Plan
- County Parks Operations Base -beyond the Site infrastructure design and
designating the areas for such activities on the Master Plan
3. PROCESS FOR CONSTRUCTION OPERATION AND MAINTENANCE AND
PROGRAMMING OF SITE
The Master Plan Committee shall recommend the following with respect to a further
interlocal agreement between the Town and County:
1. the roles and responsibilities of the park and facility construction process;
2. The roles and responsibilities for operation & maintenance of the park, including
contributions for operation and maintenance;
3. The roles and responsibilities for programming of the park
4. If desired, mechanisms for funding of additional facilities in Master Plan beyond
the County's $850,000 for the park
5. Process for deciding how to embark on next phases,,joint agreement, etc,
7
Draft 10/27/04
4. AMENDMENTS
This agreement maybe amended by mutual written agreement of the Town and County.
5. TERM
This agreement shall terminate upon the decision by the Boards of Commissioners of the
Town and County on the Master Plan, adoption of a Town and County construction and
operations interlocal agreement and the "sunsetting" of the Master Plan Committee.
6. GOVERNMENTAL APPROVALS:
Nothing in this Agreement shall be construed as waiving, modifying or granting any local
government permits or approvals which may be necessary for the development and/or
construction of any facilities or improvements, It is contemplated that the County will be
responsible for seeking and obtaining such local government approvals as may be necessary
for any work undertaken pursuant to an approved Master Plan. The party responsible for this
work shall be identified in a subsequent interlocal agreement..
7. ENTIRE AGREEMENT:
This Agreement constitutes the entire Agreement of the parties hereto.
8
Draft 10/27/04
IN WITNESS WHEREOF, the parties to this Agreement have duly and validly approved it and
caused it to be executed in their behalf by the undersigned agents.
This, the xst day of September, xxxx.
TOWN OF HILLSBOROUGH
Mayor
Attest: Town Clerk
Approved as to form and authorization:
Town Attorney
COUNTY OF ORANGE
Chair
Orange County Commissioners
Attest: Donna Baker, Clerk to the Board
Approved as to Form and authorization:
County Attorney
This Agreement has been pre-audited in the manner required by the Local
Government Budget and Fiscal Control Act.
Finance Director
tsg:orangccounty\fairvicw moa-hevised ds further rev by GEG clean doe
Fairview Campus -Preliminary Concept Plan
Draft
9
Q County & Hillsborough Parcels
~ Parcei Bountlary
Streams, Stream Bufrer. Sleep Slopes
;' Ezisling Public Works /
Storage Facility -Orange County
Pubiic Works Expansion -Orange County
Proposed Pubiic Works - Hillsborough
P/a Possible Hillsborough Public Works /
Mature Hartlwood Stand
"~ AcINe Recreation
Storm Debris
Former Landfill 8 SuAace Trash
low Impact Recreation 8 Open Space
BO 0 00 160 240 Feet
~~~
Dounly or Orange
Envimnmenl8 Resource
Conservation DepaNnenl
M Jon¢5 9I1 vI0i
10
~I~. ~,y:. ~"ej~,:
~.,~~S
\t.>.y
~\
Orange County - 42 acres
Town of Hillsborough - 25 acres
Orange County Public Works - 26 acres
Streets
Parcel Boundary
Hillsborough Town Limiits
Fairview Park Vicinity
300 0 300 600 Feet Lountyal Oraigc
Environmenl8 Resource
Conservation OeOOrimem
M Jones 51904
11
MEMORANDUM
TO: County Commissioners
.John Link, County Manager
COPIES: Gwen Harvey, Asst. County Manager
Rod Visser, Asst. County Manager
Dave Stancil, ERCD Director
Lori Taft, Recreation and Parks Director
Pam Jones, Purchasing and Central Services Director
FROM: Paul Thames, PE, County Engineer
DATE: September 30, 2004
SUBJECT: Cost/feasibility of restoring (removing landfilled material) Fairview Park
As per the request of the BOCC, this report outlining my opinion/estimate as to the feasibility/cost
to clean up/restore (remove landfill material and dress area) the portion of Fairview Park impacted
by historic landfilling activities is provided for the Board's review. The information contained
herein was originally generated in response to a request of the Fairview Park Steering Committee
and was presented to the committee by way of verbal report in Apri12004. The cleanup cost
estimate, with caveats, is as follows.
The primary caveat is that there is no accurate accounting as to the quantity or the specific nature
(toxicity, etc.) of the material that was landfilled.. For example, in its .Tiny 2002 geotechnical and
Phase II site assessment reports (excerpt copies attached), Trigon Engineering Consultants, Inc.,
estimated that the landfilled area contains between 100,000 and 200,000 cubic yards of waste. My
own estimate -based on consideration of anecdotal information indicating that landfilling practices
consisted of burying waste in discontinuous/non-contiguous trenches excavated with atractor-type
backhoe rather than in contiguous cells (current high-efficiency landfilling practice) - is that the
landfilled area contains approximately 16,000 cubic yards of waste.
A second caveat is that it is very difficult to quantify, in units that can be used to estimate
removal/cleanup costs, the amount of waste material dispersed in the landfill cover/cap (a tluee foot
fill cap was to be placed on the landfill as a landfill closure process during the Fairview CDBG of
the early 1980's) and on the surface of the wooded periphery of the landfill area The Trigon
geotechnical report noted the presence of a fill cap in 90% of the soil borings in the landfill area
with fill depths varying in thickness from less than one foot to six feet or more. Approximately
one-third of the borings contained landfill related trash and debris. An additional ten acres
(approximately) of the wooded areas peripheral to the landfilled area contain surface trash and
debris.
12
Given uncertainties as to actual quantities of landfilled and surface disposed materials and their
toxicity, I have used a number of assumptions to calculate quantities and costs for removing those
materials. I have listed both the information actually available and the assumptions that I have used
in my calculations below. The assumptions are shown in bold typeface.
• Aerial photography indicates that the actual total area in which landfill activities occurred
(primarily cleared areas) covers approximately 12 acres
• Materials were landfilled in discrete trenches rather than in a contiguous cell or cells as per
current landfill practice (anecdotal information)
• Landfilled trenches were discontinuous (anecdotal information)
• The number, location and configuration (alignment, length, width, depth) of trenches is
unknown
• The entire landfilled area was capped with at least 12" of cover during the Fairview CDBG
financed landfill closure project during the early 1980's
• Much of the landfill cover (including that in aeeas not directly over landfill trenches) has
been contaniinated with rising landfill material (pieces of metal, non-degradable debris, etc,)
• Approximately 10% of the landfill area was excavated into trenches
• Trenches were excavated to a depth consistent with that accessible to a medium size
tractor mounted backhoe (approximately 8' on average)
• Much of the material in the trench is mixed with earth material and weighs
approximately 1000 pounds per cubic yard
• The State will permit the removal of material from Fairview park
• The State will not require testing of landfilled material for hazardous chemicals, etc.
• The State will not require that material be shipped to a hazardous waste landfill
• Additional earth material from trench sides and bottoms will not have to be tested for
hazardous chemicals or excavated and disposed of as hazardous materials
• The State will permit disposal of the material in a mixed solid waste (MSW) landfill
• The Orange County landfill, nearing the end of its useful life, would accept a
tremendous volume of material (at an estimated 16,000 cubic yards, equivalent to 10%
of total annual landfilled waste) from Fairview Park
• Land£II material to be removed and re-landfilled will be classified as MSW
• Removed landfill material will be transported to and disposed of in Orange County
landfill at current tipping fee for MSW ($42 per ton)
Given the facts and assumptions listed above, the Fairview Park cleanup could generate
approximately 16,000 cubic yards (including materials lying on the surface) of material weighing
approximately 8000 tons to be transported to and re-landfilled at the Orange County landfill..
Approximately 12 acres must be stripped of cover material, that material then screened (to remove
landfill contamination) and stockpiled, to expose the landfill trenches. Once the landfill material
has been removed, trenches must be backfilled with approximately 50% of backfill material
generated by onsite earthmoving and 50% generated by importing (borrow) from offsite. Once the
earthwork has been completed, the entire area must be seeded to generate appropriate ground cover,
Removal of surface debris from wooded areas will require a great deal of hand work to minimize
damage to the existing tree cover.
1.3
The actual cost breakdown is as follows:
Grading landfill surface (strip, screen, replace cover) 12 acres $ 300,000
Excavating and loading landfill material 15,500 cubic yards $ 155,000
Hand removing and loading surface material 500 cubic yards $ 100,000
Transporting material to landfill 1070 trips (tandem I S cu yd load) $ 130,000
Tipping fees 8000 tons @ $42 per ton $ 336,000
Borrow 8000 cu yd @ $9 per cu yd $ 72,000
On-site backf 11/grading/compaction 8000 cu yd @ $5 per cu yd $ 40,000
Seed, mulch 12 acres $ 20,000
Erosion control construction, design, constm ction oversight, all permitting $ 40,000
Miscellaneous contingency mobilization (c~ 25% $ 300,000
Total $1 ,493,000
There aze a number of factors unaccounted in the figures shown above that could significantly
increase the total project cost. If the excavated material had to be transported to a landfill more
distant that the Orange County landfill, increased transportation costs might be somewhat offset by
reductions in tipping fees, but such a circumstance would probably represent a net project cost
increase, The most significant impacts on project costs would be related to either dramatic
increases or decreases in the quantity of material to be excavated (affecting excavation, borrow,
transportation and tipping fee cost elements) or by a regulatory re-categorizing of the type of
landfilled material (from MSW to hazardous waste).
For example, if Trigon's estimate of 100,000 to 200,000 cubic yards of landfilled material were to
prove accurate, the cleanup costs would increase to the $6,5 to $12 million range. Should the NC
Division of Solid Waste require that landfilled material and residual soils (those remaining at the
bottom and sides of excavated trenches) be tested for hazardous material contamination
(chlorobenzene, asolvent used in dyes and textile processing, was detected at levels well above
drinking water standards at one of the groundwater/landfill leachate monitoring wells installed by
Trigon), costs related to environmental engineering oversight and testing could have a significant
impact on overall project cost. In the event that testing does detect the presence of hazardous
contaminants at levels requiring remediation, costs associated with excavation, packaging, shipment
and disposal of landfilled materials and contaminated could be dramatic, In fact, a cleanup project
involving extensive testing and hazardous waste disposal/soils remediation could conceivably
double costs cited above (which represent relatively uncomplicated excavation and disposal work
elements).
Finally, the grading costs above reflect site repair/trench backfill to more or less existing grades and
contours and do not include costs associated with additional site grading necessary to modify the
site topography to provide for athletic fields or to remediate the relatively high background
(naturally occurring) levels of arsenic (10 to 19 parts per million [ppm], EPA remediation goal 4
ppm) detected in the Trigon studies,
An evaluation of the cleanup/remediation of the Fairview Park landfill based strictly on cost
considerations would suggest that the project would not be feasible under even the most optimistic
scenario. Assuming that the project could yield an undeveloped, 42 acre park site, potential costs
14
could range from $36,000 (at 16,000 cy of MSW) to nearly $285,000 per acre (at 200,000 cy of
MSW), Assessing the site in terms of providing approximately 12 acres active recreation area only,
potential costs could range from $125,000 (at 16,000 cy of MSW) to,just under $1,000,000 per acre
(at 200,000 cy of MSW). The very real prospect of incurring increased expenses related to
encountering much greater volumes of landfilled materials or hazardous landfilled materials during
the execution of'the project but subsequent to setting/adopting a projectbudget makes the cleanup
process ahigh-risk undertaking from an economic perspective.
If I may provide additional information or clarification of this information, please advise..
15
Report of Phase II Environmental Site
Assessment
Closed Hillsborough Landfill
Hillsborough, North Carolina
Trigon Project No. 036-00.016B
i~
COIYSULTAPiTS, IHC.
700 Blue Ridge Road, Suite 101 • Raleigh, NC 27606 • (919) 755-5011 ^ FAX (919) 755-1414
July 24, 2000
Mr. Paul Thames
Orange County Manager's Office
200 South Cameron Street
Hillsborough, North Carolina 27278
Reference: Report of Phase II Environmental Site Assessment
Closed Iillsborough Landfill Site
Trigon Project No.036-00-016B
Dear Mr, Thames:
Trigon Engineering Consultants, Inc.. (Trigon) has completed the Phase II Environmental Site
Assessment of-the closed landfill site located next to the Fairview Park in Hillsborough.. The
work was performed in general accordance with our January 4, 2000, Proposal For
Environmental, Community Relations, and Geotechnical Support (No. 036-99-091-P).
The purpose of this assessment, in conjunction with a geotechnical evaluation also completed by
Trigon, was to define the extent of the landfilling, and to evaluate whether there are hazardous
substances in soil and groundwater, or landfill gas that could pose a threat to human health o[ the
environment.
Trigon appreciates the opportunity to provide our
County. Should you have any questions regarding
please do not hesitate to contact our office.
Respectfully submitted,
TRIGON ENGINGGRING
John Gallagher, P.E. = SEAS
Project Manager :~„~~ D24199
~' ~:~'^~A~GfN1E.~
DLT:NLH
s:\ 0.360e-1\projects\2000\3600016\I6b\covltr..doc
environmental engineering services to Orange
this report, or require additional information,
~~~~
= Nyle L Hothem, P.E.
rr Senior Geotechnical Engineer
:~
I~
Orange County Trigon Project No.036-00.016E
Hillsborouelt Landfill Site July 24. 2000
TABLE OF CONTENTS
Transmittal Letter ..................... _.. .,_ .......,, ...._ .._ ,....,.... _., .....,. .,...,..i
Table ofContents . ............ ..._.........._,.... .,............,......_. ...._.,... ._.., ._,. ,.ii
1.0 PROJECT DESCRIPTION .......,. ,__ ................ _....,_....,._.,.................. ,.....,....,......1
2.0 PHASE I ENVIRONMENTAL SITE ASSESSMENT ..........................................1
3.0 SCOPE OF THE PHASE II ASSESSMENT . _ ............... ...._.,... ._.,..,....,.........,.2
3 1 Soil and Groundwater Sampling .. ................. _,,..,...., ............. _...._..,.,.....,.......3
3.1.1 Soil Sampling .....,... , ,_._ . ........ ......._... ,,. ......,.. .._.....3
3.12 Groundwater Sampling ................................. ........................ ...... .................4
3 2 Soi] and Groundwater Analyses Results-_ ............._........,......,.,_...........,...........4
3.2.1 Soil Analyses Results .......................... _. _,.,.,._,._.., _._..._........................4
3,2.2 Groundwater Analyses Results ..................... _.........,,,,.,..............,..,.,..........6
3.3 Landfill Gas _... _,._..._, .........,.,.... „ ,_.....,.,.,..._,..._.,.. _ .......... . ..... _.,...,.. , .....7
3.3.1 Background.. _..... _.., ... , .. .. .................. .... .... ...... .............7
3.3.2 Landfill Gas Assessment.. _ _ ................... _, _. _. _. _,..,.,... ,,...,..,.......,..,...7
4.0 CONCLUSIONS AND RECOMMENDATIONS ..,... _ .............._,..............,...,.,8
FIGURES
Figure 1 -Site Location Map (1967 USGS Topographic Map)
Figure 2 -Shallow Soil Boring Locations
Figure 3 -Boring Locations and Area Features
Appendix A -Boring Logs and Well Construction Details
Appendix B -Soil and Groundwater Analyses Reports
TRIGGNENGtNEE•RINGCGNSULTilNTS INC. ~ ~ ~~ Page ii
i~
Ornnge County Trigon Project No 036-00.016B
Hillsborou h Landfill Site __ 7uly 24, 2000
REPORT OF PHASE IT ENVIRONMENTAL SITE ASSESSMENT
HILLSBOROUGH LANDFILL SITE
IIL LSBOROUGFI, NORTH CAROLINA
Trigon Project No 036-00-016D
1.0 PROJECT DESCRIPTION
Trigon Engineering Consultants was retained by the Orange County Manager's Office to
conduct a Phase II Environmental Site Assessment (ESA) of the 67-acre parcel of land
that includes the closed Hillsborough Landfill. The goal of this assessment, in
conjunction with a geoteclmical evaluation of the property also completed by Trigon, was
to define the extent of the land Filling at the property, and to evaluate whether there aze
hazardous substances in soil and groundwater, or landfill gas that could pose a threat to
human health or the environment.
The prgject site is located near the Fairview neighborhood in Hillsborough, North Cazolina
(see the Site Location Map included in Figure 1) The approximately 67-acre property is
comprised of hvo tracts of land: a wooded, 25.4-acre tract owned by the town of
Hillsborough, and an abutting 41.75-acre paroel owned by Orange County.. The county's
portion of the site is a mix of open and wooded areas, including approximately 10 acres that
was used as a refuse and debris landfill starting in the 1950's until the early 1970's
2.0 PHASE I ENVIRONMENTAL SITE ASSESSMENT
2.1 SUMMARY OF THG PHASE T GSA
On May 18, 2000, Trigon completed a Phase I Enviromnenta] Site Assessment (ESA) on
the Hillsborough Landfill site. The Phase I ESA was completed in general accordance
with ASTM E-1527 "Standard Practice for Environmental Site Assessments: Phase I
Environmental Site Assessment Process."
TRIGONGNGINEERlNG CONSULT.IN7S, INC Page 1
l~~
Qrange County 7rigon Project No.036-DO-016II
Hillsboroueh Londfill Site July 24, 2000
The Phase I ESA included a review of available environmental records, interviewing
persons knowledgeable of the site history and the landfilling activities, and conducting a
site reconnaissance. As a result of the Phase I ESA, Trigon reached the following
conclusions:
• For approximately 20 years, from the 1950's until the 1970's, a portion of the site
was reportedly used as a municipal landfill for the Town of Hillsborough.
• Automobiles and some industrial wastes, including fabric from local textile
manufactures, may have been disposed of in the landfill.
• The site was permitted and operated as a Land Clearing and Inert Debris (LCID)
Landfill, permit No. 68-B, from the early 1970's until 1994.
e The site is currently vacant, grass covered and wooded, The northeastern section of
the site is utilized as a stump, tree and limb disposal site where chipping activities
tape place.
• A baseball field has been constmcted in the northwestern portion of the site,
adjacent to the Fairview Park. Fill soils have been brought from off-site sources for
construction of the baseball field.
• Some solid waste, included mostly rusted metal objects, glass bottles and trash,
was observed in the woods near the perimeter of the property.
3.0 SCOPE OF THE PHASE TI ASSESSMENT
The Phase II ESA. included sampling and analyzing soil and groundwater at the site, and
an evaluation of landfill gas (methane) to determine if Hazardous substances are present
that could pose a ttrreat to human health or the environment More specifically, the Phase
II ESA included:
• Analyzing four composite and two discrete soil samples collected at the property
and one background sample collected from an off-site location;
• The installation of rivo groundwater monitoring wells, and the collection and
analyses of groundwater samples from those wells;
• An evaluation of the landfill gas generation; and
• A comparison of the contamination measured in soil and grotmdwater to
applicable state and federal guidelines and standards.
TRIGON ENGlNEElUNC CONSULTiiNTS, INC. Page 2
ao
Orange County Trigon ProjeclNo 036-00-OIGB
Hillsborouzh Landfill Site - J~ 24.2000
3.1 SOIL AND GROUNDWAT>;R SAMPLING
3.1.1 Soil Sampling
In February 2000, Trigon collected soil samples from the ground surface to 1.,5 feet below
ground surface using a hand auger in the northwestern portion of the property, including
the baseball field constructed by Fairview neighborhood residents, Tluee lines of four
soil borings each were advanced in this area (see Figure 2)..
The soil saniples from each line of four borings were composited for a total of tluee
samples (SS-1 tluough SS-3). In addition, one background sample, 55-4, was collected
from a single location approximately 500 feet to the west of the property boundary in the
Fairview Park, These samples were sent to Paradigm Analytical Laboratories, Inc., a
North Carolina-certified laboratory, for analyses.
In April 2000, Trigon began work on the geoteclmical evaluation of the property to assess
the subsurface conditions at the site, and to delineate the landfill area. The work included
advancing 49 geotechnieal borings across the 67-acre property.. Soil samples were
collected from eight of the geoteehnical borings in the central portion of the property in
areas expected to be the location of past landfilling activities.. Those eight samples were
collected from the surface to a depth of nvo feet, and then were composited into one
sample (SS-5) for analysis. In addition, two discrete soil samples (SS-6 and SS-7) were
collected from the borings advanced for the two monitoring wells (MW-1 and MW-2)
subsequently installed in the central portion of the site.
All soil samples were collected in accordance with procedures outlined in the
GTOUndwater• Sectiorr Guidelines far the Jm+estigation and Remediation of Soil and
Groundwater, Volume II, January 2, 1998,
TRlGONL'NGINL•L•RlNG CONSUL TAN7S, ING Page 3
ai
Orange County 7rigon Project No D3G-00.OIGII
Hillsborough Landfill Site _ 7uly 24. 2000
3.1.2 Groundwater Sampling
Iwo, Type II growndwater monitoring wells were installed in the central portion of the
site (see Figure 3). The wells were installed on either side of the creek that divides the
landfilled area because this was determined to be a likely discharge point for groundwater
and potentially leaclrate generated from the land£II. Following installation, these wells
were developed, purged and sampled in accordance with the Groundwater Section
Guidelines for t/re Investigation mrd Remediation Gf Soi( and Grroundwater, Volume II,
Ianuary 2, 1998.. Groundwater was measured at approximately 5.2 feet below ground
surface in MW-1, and approximately 1.3 feet below ground surface in MW-2. Boring
logs, including well construction details, aze included in Appendix A.
3.2 SOIL AND GROUNDWATER ANALYSES RESULTS
3.2.1 Soil Analyses Results
The four soil samples collected in Febntary 2000 from in and around the baseball field,
and the sample collected from the central portion of the property and the two well borings
in April and May, 2000 were submitted to Paradigm Analytical Laboratories- The
samples were analyzed for volatile organic compounds (VOCs) by EPA Method 8260B,
semi-volatile organic compounds (SVOCs) by EPA Method 8270, pesticides and PCBs
by EPA Method 808Q, and RCRA and priority pollutant metals. A summary of the
analyses results are provided in Table 1 below.
No VOCs, SVOCs, pesticides or PCBs were detected above their respective quantitation
limits in any of the soil sanrples With the exception of arsenic in six of the seven
samples, including the background sample, no metals were detected at concentrations
above their respecfrve Remediation Goals (RGs} established by the North Carolina
Department of Environment and Natural Resources (NC DENR) pursuant to the Inactive
Hazardous Sites Response Act of 1987 (N,C.G.S. 1.30A~310 et. se9.). The complete
laboratory reports are provided in Appendix B.
TRIGON L'NGlNEL•1UNG CONSULT.INTS, INC. Page 4
as
Orange County Trigon Project No 036-00.01GB
Hillsborough Landfill Site ~_ July 24, 200D
TaGle 1 - Soi! Anal ses Results (nr Ar )
' ~ '
i
2. _.. ~~,: ~. Retaedtatton
~ Goal
__ .,<:- ~ ~ SS 1 ~r
,~•.:.. .i. a SS 2
~
sir a SS 31. ,
~ ~
.....:.. +ss~ l f
(Baakgiound
,._ 1 ,
.~.: Sent le l .SS'$ i
,
.. ,~_. _ jSS 6 i'
, ~
.. . ~-tS3 7,~
f ~
e ;
,-',~.....-~~
Antimony 6 2 BQL BQL BQL. BQL BQL BQL BQL
Arsenic 4 6 10 13.4 19,7 10.5 6.87 4-69 2 30
Beryliium 0.15 NA NA NA NA BQL BQL BQL•
Bnrinm --- 54 9 46 7 80.7 79 0 NA NA NA
Cadmium 7 8 2 73 3 19 4 21 1.69 Z 75 2..17 BQL
Chromium --- 8 19 11 7 18,4 13.1 81 4 4 77 19 8
Copper 620 NA NA NA NA 44 6 20 8 107
Lead 400 625 277 382 733 BQL 10.7 BQL.
Mercury 4 6 0.0.31 BQI: 0 O6 0 0324 0.03 0.054 0.027
Nickel 320 NA NA NA NA 57.7 BQL I61
Selenium 76 BQI. BQL. BQL BQI. BQL BQI. BQL
Silver 78 BQI. BQL BQL BQL BQL BQI. BQL
Thallium 126 NA NA NA NA BQL BQL BQL
Zinc 4,600 NA NA NA NA 73 4 96 4 71 6
VOCs -- BQL BQL BQL. BQL BQL. IIQL. BQL
SVQCs --- BQL BQL BQL BQL. BQL. IIQL BQL.
PCBs --- BQL. BQL. BQL BQL. BQL. BQL. BQL
Pesticides --- BQL. BQL BQL BQL. BQL SQL BQL.
`k BQL -Below Quantitation Limit
NA -Not Analyzed
The arsenic concentrations in soil ranged from 2.:3 milligrams per kilogram (mg/kg) to
19,7 mg/kg. The off-site background sample (SS-4) had a measured arsenic concentration
of 1 Q 5 mglkg. The NC DENR Remediation Goal for arsenic is 4-6 mg/kg
TRIGGN ENClNC•ERING CGNSULT.iN7S, INC. Page 5
a3
Orange County I'rigon Project No 036-00-016B
Aillsboroueh Landfill Site July 24 2000
3.2.2 Groundwater Analyses Results
Groundwater samples from the two wells were submitted to Paradigm Analytical
Laboratories, and analyzed For VOCs by EPA Method 82608, SVOCs by EPA Method
827D, pesticides by EPA Method 8081, PCBs by EPA Method 8082, and priority
pollutant metals.
The results of the groundwater analyses are provided in Table 2 below, The table also
lists the Gross Contaminant Levels (GCLs) standards established to be protective of
groundwater not used as a source of drinking water; and the North Carolina drinking
water standards (15A NCAC 2L ,0202). Only those analytes measured at detectable
concentrations in gtoundwater are summarizedrn the table, The complete laboratory
report is provided in Appendix 8
Tn6ro 7 _ /:vnnrrdiunlor Aunlv.ces Results
'~ ~ANAL"Y~T1; ~
' _,:' _ GCL ~ '
r. r..
-' :Standard'":. 2L
., ~
'StaniiaYd
,MW 1e ~. "''
1 ~3r,2`l,
Chlorobenzene (ugQ.) No Std 50 140 BQL
1,3 - Dichlotobenzene (ug/L) 61,500 NA BQL. I
1,4-Dichlorobenzene(ug/I.) 39,500 NA BQL, 1
Naphthalene(ug/L.) 15,500 2t BQL 3
1,3,5 - Trimethylbenzene (ug/L) _ 25,000 NA BQL. 4
1,2,4 - Trimelhylbenzene (ug/L) 28,500 NA HQL I1
Lead (mgt) I S 0 016 BQL 0.024
Mercury (mglL-) No Std 0.0011 HQL 0.0003
Zinc (mg/L.) No Std 2 1 BQL 0.0679
No contaminants exceeded their respective GCLs And, with the exception of
chlorobenzene in MW-1 at a concentration of 1d0 micrograms per liter (ug/L), and lead in
MW-2 at a concentration of 0 024 milligrams per liter (mg/L), no contaminants were
measured present above North Carolina's 2L drinking water standards.
TRIGON ENGINEEIUNG CONSULT.INTS, /NC. Page 6
a~-
Orange County Trigon Project No. 0.36-00.Ot6B
Hillsborou h Landfill Site Iuly 24.2000
.3.3 LANDFILL GAS
3.3.1 Background
Landfill gas is a product of biodegradation of refuse in landfills, and consists of primarily
methane, carbon dioxide, water vapor and traces of other non-methane organic
compounds (NMOCs). The amount of gas generated and its composition is dependent on
the type of mate[ial disposed, the age and capacity of the landfill, local climate and
rainfall, and other parameters
The U..S. EPA has established performance standards for the collection and treatment of
landfill gas and other emission guidelines for relatively large landfills (i.e., 2.5 million
tons of waste or 2.5 million cubic yazds), Smaller landfills are not regulated by these
federal standards However, constmction and other site improvements in and around
landfilled areas, regardless of size, need to take into account the potential for landfill gas
generation and the hazards that it may pose.
3.3.2 Landfill Gas Assessment
Refuse was observed while advancing the geotechnical borings across about ten acres of
the property. Assuming that on average, the refuse is ten feet deep across the area where it
was observed, the closed Hillsborough Landfill would be expected to contain from
100,000 to 200,000 cubic yards of waste. Consequently, a landfill of this size is
considered small with limited potential to generate substantial amounts of landfill gas. At
approximately one-tenth of the tT.S• EPA threshold, it is also not subject to the federal
regulations that would require collection and treatment of the landfill gas.
Trigon monitored for the presence of landfill gas (measured as methane) using a Foxboro
organic vapor analyser and a MSA Gasscope landfill monitor while advancing the test
borings for the geotechnical evaluation. Methane was concentrated in borings that
contained refuse, especially in the landfill area close to the creek. No methane gas was
detected in borings elsewhere at the site that were free of refuse and debris.
TRIGON LNC/NEERING CONSULTANTS, !NC- Page 7
a~
Orange County Trigon Project No 036-00-OIGB
Hillsborou h Landfill Site 7uly 24, 2000
When the methane gas was encountered during drilling, the augers were charged with
water to displace the gas for safety purposes.. Trigon observed no stressed vegetation on
the landfill surface that is an indication of substantial gas migration through the landfill
material to the ground surface and atmosphere..
4.0 CONCLUSIONS AND RECOMMENDATIONS
• Based on the geotechnical borings advanced across the property, a ]andfilled area of
approximately ten acres was found to contain refuse and deb*.is
• No soil contamination, with the possible exception of arsenic, was detected at
concentrations above Remediation Goals established by the NC DENR.
• Arsenic was measured in soil at an average concentration of 9.5 mg/!cg and ranged
from 23 to 19.7 mg/kg- It was also detected in a background sample at a similaz
concentration of 10..5 mg/kg, While above the NC DENR Remediation Goal of 4.6
mg/kg, these concentrations fall within the range that the LT..S. EPA considers
"average and common" (USEPA, Office of Solid Waste and Emergency response,
EPA/540/S-9G/500, December 1995).
• No groundwater contamination exceeded the NC DENR standards established to be
protective in situations where groundwater is not used as a source of drinking water.
And, with the exception of chlotobenzene and lead, no contaminants were present
above North Carolina's stringent drinking water standards.
• The landfilled area at the site have the potential to generate methane and other landfill
gases, bttt not at rates subject to federal regulations that would require it to be
collected and treated. However, future construction and other site improvements in
and around landfill need to take into account the potential for landfill gas generation
and the hazards that it may pose.
TRlGGNENCINEEItrNG CONSULT.INTS, INC. Page 8
a~
FIGURES
Figure 1 -Site Location Map
Figure 2 -Shallow Soil Boring Locations
Figure 3 -Boring Locations and Area Features
a --~
J
`/
,_
'--?`~ ~~, ~ t
- ~~ Ii
`:4
_~::...
~\
~~
\~
111
' /1
./ ;`\
~~D~~ 36079-A 7 ~TF024
19Ge
OUADDANGLE LOCATION REVISED 7994
HCINEEftiNO CONSULTAMS.INC
SITE LOCATION MAP
Former Town of Hillsborough Landfill
JOB No. 036-QO-016_ _ _
DATE: March 2000 _
SOURCe:~ IJSGS Quadrangle "Hillsborough, N.C.
Scale 1 Inch = 2000 feet Figure 1
zs
,~~ ,~ ,,~j, ,
. ~ ~lli`i" ( ~
~. L`
~,\ _ _ L
/, •\~
. 111 ~~ / i. i
I i D I bnLE
1000 D 1000 1000 3000 <OM 5EA0 5000 7600 ~EEf
HILLSBOROUGH, N. C.
il_ I ~~
S > 7, _.
.~~I i;
I ~~ ~~ ~'
~. ;
1j a ~ I',
~,
'il _..i o_''-.
c~
^ 32500' ~ .j,
CLEARED MQWED FIELD
~L
~^ ~
B-12 ®B-8 ~ B-4 .v' v
. ~.-
U ~~
.y.
8-11 ~ B-6 ®B-3 ~ ~~
0
P
O
® 8-10 ® 8-6 ® 8-2
~___
,-~
~ .~
`L. '~
i
i i
~ ~
i
i ~
i
B-9 ®8-5 ~ 8-~ ~~
J,•
`~----____.~
EXIS"TING BASEBALL L
DIAMONb .L-
,~
.(. .L
..~" .t.
.L ~L
- .L
.1. .- J.
~ENSE WOO~OS
.t, . ~ .~.
NOTE BORING LOCATIONS ARE SPACED B8' SOUTH TO NORTH AND 81.25' EAST TO WEST,
STARTING FROM SOUTHEAST CORNIER OFSOUARE
SHALLOW SOIL BORING LOCATIONS
FAIRVIEW PARK: HILLSBROUGH, NC
JOB No. 036-00-016
DATE: JULY 2000
DRAWN BY: BL
SCALE : As Shown FIGURE: 3
~~
~ ~
;~
~~
< ~ ~ ~~
I.
NUPiREE ROPD ~=\ I ~ X a. N
S ¢~ to ~ mQ o
~\ ` \ a 6 ~yJ CS N
~~ ¢ ¢ q J J
O a o ~ m
s
~ ~ w N
J 3 i ~ -1 ~ d i i Z~ m¢
couRr) e a e a i -~ i a a ~ m ~ o o vi
~~ i d i i i ~3 ~ d _ ,a.
i ~ 9 ~ ~ m n
i i i ~~~~'~ ~~ %~ ~m G
"%`'/ ^ ~
~~ ~~ ~ ~ ~ ~ ~i ® ~' Q
~~~~ ~ ~ F-
m
/ ~ ~ )
AWE gVENUE
<~ dl a .~ i j
__ _ ~
5 ~ _ ~
// _ =® i i i
~~ - ~ i i d
I ~ ~~ ~
_ °~ d 9 ® j s
wore aoENUE Q~ - -~ ~ i i j 3
z ~~ Y m j i i j
~ = m ~
~ ) ~ '~ j ~) d j °~
~ 9~ ~® ~ ~ ~ j j $ i a
o /
H0.NEMOM gVEryUE ~ ) i ~ ®-) j
G j ~ i ~ i 3
j i / -1 0 -1 j i ~ o
s e e a a a -~ a~ a
e a
a~ a a e a -~ a® -> j
N/APER STREET ww j j® j i s ~ o d j j j 3
i j j ~ ~ d 3 i ~ e 9 s
$ S
i d ~i i j j 9 ~ i j ., ~ S~S
j ® .> ~) j i i 9 a
d i
)P~
~,~~% ~"'
O C/ \/ pLp
5 uw \ N~ ./ ~ ~ e d®
a
~~~ ~~
,~ L~
Report of Geotechnical Evaluation
Closed Hillsborough LandPili Site
Fiiilsborough, North Carolina
Trigon Project No. 0:36-00-016A
~i
COI`ISULTAI`ITS, [IYC.
700 Blue Ridge Road, Suite 101 ~ Raleigh, NC 27606 ^ (919) 755-5011 ~ FAX (919) 755-1414
July I9, 2000
Mr. Paul Thames
Orange County Manager's Office
200 South Cameron Street
Hillsborough, North Carolina 27278
Reference: Report of Geotechnical Evaluation
Closed Hillsborough Landfill Site
Trigon Project No. 036-00-016D
Dear Mr. Thames:
Trigon Engineering Consultants, Inc. (Trigon) has completed the subsurface exploration and
geoteehnical evaluation of the closed landfill site located next to the Fairview Parlc in
Hillsborough. The work was performed in general accordance with our January 4, 2000, Proposal
for Environmental, Community Relations, and Geoteclmical Support (No 036-99-091-P).
The purpose of this study was to explore the general subsurface conditions, and to evaluate those
conditions with regard to future site development. Additionally, the investigation was to
delineate the approximate aerial extent of t11e refuse and rubble landfilled at the properly. This
report presents our findings, along with our conclusions and recommendations for design and
construction
Trigon appreciates the opportunity to provide our geoteclutical engineering services to Orange
County. Should you have any questions regarding this report, or require additional information,
please do not hesitate to contact our office,
Respectfully submitted,
TRIGON 1!/NGINGI;RING CONSULTANTS, INC.
Jo Gallagher, P.E!
P ject Manager
~~
025257
Nyle L. Hothem, P.E.
Senior Geotechnical Engineer
DLT:Ni.H
h:\ 0360c-IlprojccLS\2000\360001 G\I Gdlgcatech doc
Otange County Trigon Project No. 036-00-016D
Hillsborough Landfill Site _____ July 19, 2000
TABLE OF CONTENTS
Transmittal Letter...,.,..,_ ........................................................................................_.......,.,..._.., ...r
Table of Contents ..............._,..........,......,...,.........,..,....,....,... ,....,......._......_.._,...,,..._,...,..._......ii
1.0 SITE DESCRIPTION .............................._,,....,,,...,...........,...,...._.....,..................,.,,....., ....1
2.0 SCOPE OF INVESTIGATION,.,.. ,.__ ............................._,................. _. ,..,...,....,.__..,.,,.1
2.1 Field Exploration ......................... .......................................... ................._...,.,.....,....,1
2.2 Laboratory Testing ........ ................................................................................................2
3,0 SITE AND SUBSURFACE CONDITIONS ...........................................,..,......,,.,,......,,,2
3,1 Site Conditions............ .......................................................................__,,.......,,,.,,.,,,..2
3,2 Subsurface Conditions ..................................................................................................3
3,3 Groundwater Conditions ......................................................_.,.........,.,,.....................5
4.0 CONCLUSIONS AND RECOMMENDATIONS ................._....,, ....,.., .......,..,,...,.,.....5
4,1 Basis ..........................._.,.......,...,._....,.....,......_......._.,........._............,...._,...._.,. .._ ..,-..5
4.2 Design and Construction Considerations ........................................................................5
5.0 CLOSURE AND LIMITATIONS ....................._..__............, ...,... , ,.,,.,__...,.,.,,.....,...,...7
APPENDICES
Appendix A -Figures
Figure 1 -Site Location Map
Figure 2 -Boring Locations and Area Features
Appendix B -Test Boring Records
TRIGONENCtNEER1NG CONSULTANTS, JNC. Page ii
33
Orange County Trigon Project No 03G-00-016L)
Hillsborough Landfill Site 7uly 19, 2000
REPORT OF GEOTECHNICAL EVALUATION
HILLSBOROUGH LANDFILL SITE
HILLSBOROIJGIi, NORTH CAROLINA
Trigon Project No 036-00-O1GD
1.0 SITE DESCRIPTION
The project site is located near the Fairview neighborhood in Hillsborough, North Cazolina. See
Site Location Map {Figure 1) included in Appendix A.. It is comprised of two tracts of land: a
wooded, 25.4-acre tract owned by the town of Hillsborough, and an abutting 41.75-acre parcel
owned by Orange County. The county's portion of the site is a mix of open and wooded areas,
including approximately 10 acres that was used as a refuse and debris landfill starting in the 1950's
until the early 1970's.
2.0 SCOPE OF INVESTIGATION
2.1 TII;LD 1;XPLORATION
The field exp]oration for this project consisted of forty-nine (49) soil test borings extending to
depths of 43 to 10.0 feet below existing grades at the approximate locations shown on the
Boring Location Diagram (Figure 2) included in Appendix B. Borings B-2 and B-17 were not
drilled due to their outlying location and difficult access in heavily wooded areas at the site.
The boring locations were established in the field by Trigon personnel using a preliminary site
plan provided by Orange County. The borings were positioned in the field in a general grid-like
pattern by estimating distances and right angles from existing site featrtres shown on the site plan
provided.. After completing the field work, the borings were located with global positioning
system (('iPS) instntments, referenced to a set coordinate system and plotted on the Boring
Location Diagram (see Appendix B). Brief descriptions of the field testing procedures and Test
Boring Records are included in Appendix C.
TRIGONENGINEERlNG CONSULTiIN7S. ING Page 1
3~-
Orange County Trigon Project No. 036-00-016D
Hillsborough Landfill Site _~ July 19, 2000
Upon completion of the boring program, the recovered samples were rehtmed to Trigon's soils
and materials testing laboratory, where they were visually examined and placed in groups of like
materials. A laboratory log of each boring was prepared based upon drillers' field logs, laboratory
test results and visual classification. Test boring logs are included in Appendix C. The logs
summarize the primary strata encountered, the depth of each stratum change, the depth of
sample, Standard Penetration Test results, groundwater conditions and laboratory test data. The
laboratory logs were prepared for each boring giving the appropriate sample data, and the texhtral
description and classification.
2.3 LAI30RATORY Tr,STING
Representative samples recovered from the borings were visually classified in general accordance
with the Unified Soil Classification System (USCS). Due to the preliminary nature of ttris study,
laboratory testing was not perfomted-
3.0 SITE AND SUBSURFACE CONDITIONS
3.1 SITE CONDITIONS
This pt'operty is a rectangle shaped parcel consisting of approximately 67 acres. The property is
accessible from the south off Torain Street from the east by the Orange County property, and
from the northwest by the Fairview Park.
Approximately half of the site is wooded with small to medium diameter trees. The northeastern
section of the property is utilized as a stump, tree and limb collection azea where chipping activities
take place Cleared areas are present in the central portion of the site, and a baseball field,
reportedly constructed by the residents of-the Fairview neighborhood, is located on the northwest
portion of the property.
According to the USGS 7.5-minute "Hillsborough, NC" Topographic Quadrangle (see Appendix
A), the topography in the site vicinity is characterized by moderate relief: The northern portion of
TRJGONENGINEERINGCONSULTi1N7S, lNC. ~ Page 2
~S
Orange County 'Irigon Project No.036.00-01 GD
Hillsborou¢lr I.andf'ill Site July 19, 2000
the site is occupied by a ridge that runs east and west, and slopes to the north and south. The site is
bisected by a stream that nms east and west. The southern portion of the site is also occupied by
ridges and valleys with moderate relieG The elevation of the site varies from 620 to 680 feet above
mean sea level. With the exception of minor ponded water on the northeastern portion of the site,
no surface impoundments, lagoons, or holding ponds were observed on the property, Surface
water appears to flow to the central portion of the site and then drains to the east via a small
creek.
3.2 SUBSURTACI; CONDITIONS
According to the 1985 Geologic Map of North Cazolina, the site is located within the Cazolina Slate
Belt of the Piedmont Physiographic Province. Surficial soils in the vicinity of the subject property
consist of residua] soils derived from chemical weathering of the local bedrock. Local bedrock
consists of medium to dark green metavolcanic rock.
According to the Soil Sruvey Gf Orange CGUnly, North Carolina, the predominant soil types are
in the Geotgeville and Herndon soil series. These well-drained soils are typically found on
uplands of the area, and are typically dark yellowish brown silt loam
The generalized subsurface conditions, as interpolated from our borings, are described below.
For descriptions and general stratification at a particular boring location, the respective Test
Boring Record should be reviewed (see Appendix C). Subsurface conditions between boring
locations or elsewhere on the site may vary, and undetected subsurface anomalies may exist
between boring locativns,
Subsurface conditions across the site varied greatly from boring to boring, Generally, the borings
encountered FILL soils overlying natural residual soils or partially weathered rock (PWR) to
boring tenrrination depths ranging from 4.3 to 10.0 feet below existing ground surface. The
existing FILL soils were generally a sandy clay (CL) to sandy silt (ML); approximately 20% of
the borings also contained refuse, rubble or debris, The natural residual soils were generally
TRLGONENGINEER/NGCONSULT.INTS, INC Page 3
~~
Orange County Trigon Project No 03G-00.076D
Hillsborough Landfill Site 7uly 19, 2000
described as a sandy silt to sandy clay, and agreed with the general description provided in the
SGil Survey of Ormrge COirilty, North Cm•olina
The Soi] Boring Summary table below describes the boring locations, depth to fill (if present),
and whether refuse was encountered in the boring,
SOIL BORING SIJMIVIARY
-sllormgc~.
;_ ~7Vp ~,. } ~.DeQlGofG
r,ELLL t '~~1Refuse~~,«t
?Errcor(ii[er"e"rl
B-I None
B-2 ND
B-3 4S Yes
B-4 None
B-5 None
B-6 6.5 No
B-7 2 0 Yes
B-8 .3 S Ycs
B-9 3 0 No
B-10 5.5 No
8-11 3 5 No
B-12 4 0 No
B 13 6 5 No
B-14 4 5 No
B-IS 3 S No
II-16 4 0 No
B-17 ND
B-18 None
B-19 None No
B-20 7 5 Yes
B-21 3 0 No
B-22 3S No
B-23 3 0 No
B-24 None
B-25 8 S Ycs
B-26 4.0 No
~']Iorrng;
M1+'~No''z'' h+,?fePn(r °~ar
,.F.(!/ t. ulg ~~ ~tefi~se i,~t',-_'~v'.
~-~Errcou rr (ererl=•
B-27 3,5 No
B-28 3 0 No
B-29 5.5 No
B-.30 3 0 No
B-31 4 5 Yes
B-32 ZS Yes
8-33 3 0 No
B-34 .3 0 No
B-3S 3 0 No
8-36 S.S Yes
B-37 6 5 Yes
B,38 None
B-39 None
B-40 None
B-41 7 5 Yes
B-42 3 0 No
B1t3 3 0 No
B-44 None
B-45 I 0 No
$-46 None
B-47 3.0 No
B-48 4 0 No
B-49 3 0 No
B-SO None
B-S 1 None
ND =Not Drilled
Partially weathered rock (PWR), described as weathered rock material Fvith N-values of greater
than 100 bpf but less than auger refitsal, was encountered in 26 of the 49 borings across the site
at depths ranging from O.S feet to 9.0 feet below the existing ground surface.
T/UGONENGfNL•EftlNGCONSUL-TilNr$ INC Page 4
.~1
Orange County Trigon Project No. 036-OD-016D
Hillsborough Landfill Site 7uly 19, 2000
3..3 GROUNDWAT);R CONDITIONS
Groundwater was encountered in 17 of the 49 borings across the site at depths ranging from 1 0
feet to 6.5 feet where encountered. It should be noted that fluctuations irr groundwater levels can
occur due to seasonal changes in precipitation and surface water runoff. Seasonally high
groundwater levels usually occur during or ,just after the typically wetter months of the year
(November through April). _
4.0 CONCLUSIONS AND RECOMMENDATIONS
4.1 Basis
Based on a review of the boring logs, the most significant deposits of refuse, rubble and debris
appeazs to be generally toward the center of the site, and to the north and south of the existing
creek. Trash and debris was encountered in 10 of the borings as noted on the Soil Boling
Summary table in Section 32, Subsurface Conditions, and the boring logs and profiles provided
in Appendix G
The existence of FILL soils in borings between those that encountered trash and debris indicate
that landfilling practices were random and widespread. This is consistent with information on
landfilling operations described by personnel who worked at the landfill (see Trigon's Report of
Phnse I Environmental Site Arsessmertt). Please refer to the maps, Boring Logs and Subsurface
Profiles provided in the appendices of this report for more specific information.
4.2 Design and Construction Considerations
The development options for'the project site aze limited due to 1) the variable depths of existing
FILL material throughout much of the site, and 2) the presence of refuse and rubble debris found
in a number of the soil borings. The following is a highlight of the most significant design and
constmction considerations for development of the silo, The conclusions and recommendations
provide general design and construction considerations for excavation and grading, stmcture
loading, and pavement and athletic facility improvements. As more specific uses aze being
TRIGONENGlNEL1UNGCONSULTiiNTS, INC Page 5
~8
grange County Trigon Project No 036-00-016D
Hillsborough Landfill Site _ July 19, 2000
considered for the site, Trigon could assist the design team with developing the most practical
and cost-effective design and construction options for development.
Excavation and Grading
Excavation at the project site could encounter refuse and debris that may require off-site disposal
at a permitted landfill. To avoid this situation, it is recommended that planned grades be based
on raising the site with structural fill and supporting new construction on, or in the new structural
fill. The new fill will also serve as a positive barrier to minimize exposure to any of the existing
refuse and rubble fill materials,
LiPhtly Loaded Structures
In our opinion, lightly loaded structures could be supported on shallow depth mat foundations
designed to spread the structural loads over a large area, thereby significantly reducing the
bearing pressures that could be transmitted into the existing FILL soils. Provided the mat is
designed to be a structurally rigid member, it is anticipated that the movement caused by
settlement could be tolerated without resulting in structural failure.
Moderate to Heavily Loaded Structures
Although the existing FILL soils generally appear to be firm to stiff, the magnitude of settlement
under moderately to heavily loaded foundations cannot be estimated within reasonable design
tolerances. Furthermore, the refuse encormtered in several borings is unsuitable for support of
most structures for the same reason, and is likely to exist in localized to widespread deposits
throughout the site.
Moderate to heavily loaded structures would require the use of foundations extending into the
natural undisturbed soils underlying the existing FILL soils. The most common foundation
options would include:
I) Shallow depth spread foundations. However, this option would require removing the
existing FILL soils and replacing with a controlled structural fill to support the spread
foundations,
T/UGGN ENGINEERING CGN$UITiiNr$ INC. _ Page 6
Orangc County Trigon Project No 036-00-0161)
Hillsborough Landfill Site ,__- July 19, ZOOD
2) A deep foundation system of drilled piers penetrating the underlying natural soils and
partially weathered rock. -
3) A foundation system of GeopiersOO a stone columns extending into the underlying
natural soils and partially weathered rock.
Pavements and Athletic Fields
One possible improvement of the site is reportedly the construction of athletic fields and other
similar recreational facilities. Ball fields and soccer fields are not expected to be severely
impacted by settlement of the existing FILL soils, however, some future maintenance, including
regrading of the surface, can expected. Similarly, basketball and tennis courts could also be
supported by the existing FILL soil without experiencing major failures. However, it is quite
possible that the courts could experience some distress to the point that the pavement could crack
and the surface could become uneven.
The soils encountered at the boring locations should provide adequate support for pavements,
However, the subgrade tivill need to be prepared to support the pavement section including
placement of a compacted structural fill and possibly the use of geosynthetic reinforced earth
fills.
5.0 CLOSURE AND LIMITATIONS
Regardless of the thoroughness of the geoteclurical exploration, there is always a possibility that
substuface conditions will be different from those at the boring locations, that conditions will not be
as anticipated by the designers, or that the construction process will alter soil conditions. Therefore,
qualified geotechnical personnel should observe the prepazation, earthwork, and shallow foundation
consWction to confirm that the conditions anticipated in the design actually exist.
TRIGON ENGINEEIUNG CGNSULTi1NTS, ING Page 7
APPENDICES
TR/GGNENGfNEERING CONSULTANTS, INC.
~"~
Appendix A
FIGURES
4a
.r'--
NC ~
GUADBANGLE LOCATION
ENGWEEAING CONSULTANTS, INC
HILLSBOROUGH, N. C
36079-A1•TF~~024
19G8
REVISED 1994
"ION MAP
Former Tawn of Hillsborough Landfill
.LOB No. 036-00-016
DATt=_: March 2000
souRCE: USGS Quadrangle "Hillsborough, N
Scale 7 inch = 200D feet Figure 1
i } 0 I MILE
1000 0 1000 3000 , 3000 Appp 5000 6000 7000 CECI
N
~ ~ ~ N
l ~ ~ ~z
LL ~ ~
N ~ = CI
LL
9 ¢ d' K
O
mun NLIatREE ftOM (~ \~~ % ~ ~
\ ~ S ¢ t4 ~ ~o 00
a
~ ~ J J
c U Qa o -~+ m
~ ~ N
J
i i i i i i i i z~ m~
cLEO ~ i i i i i i i i ~ O LL Z ~ w
coum a i i i i i i i i ~ m o a ~a c~i
>o o~n
i i i i i i i i
i i ~i i i i i i m ~.
i ~ i ~ '- '^
i i ~i - a ~
i i i ~' - ,~/ ~ Z
i i i r'~ Q
~ /~ ~s u o
v i i i ~ ~ {J
~ ° e ~ / ~~
i mi ~
i ~ '~ ~
~~~ ~ i ~ i
., i i
OWE AVENUE i ~ i
/;~==_-.viii
-_ - i i i gg
~ ) i~ i 3
__ ~ d d ~ 9 $
W00LE AVENUE -- i i i g
~ ~
- ~ i i i i d
i' ~ ~
S a ~ i i i ~
g '1 / ~ ~ ~ s
)~m i i i i g3g
~ i i $ i 2
o,~/~
NOMEMUNi AVENUE ) / i rr i ~i i °c
8 i11
B i i i i i ~
i i ~' iii i i ~ m
s i i i i i i i i
~ i~ i i i i i iii i
"""ft~ i i~ i i~ -) ~ i i i i ~
SHEET wpm °
a i i~ c i l i a S~S ~~
i i i i i i i i 6 9~
i i Lei a -) i i 3~ i e ~ g ~_
i~ i i i i i i ~
m„~ i i ~ ~ •
~ ~ ~~' .~
G~ ~ ~
~ ~ ~~~~ ~
~~~ oa
~~