HomeMy WebLinkAboutSEPA Exemption for Geotechnical Exploration - SEP Determinations - 5/22/2009 ca 4=
DAVID EVAN
Memorandum
DATE: May 22
TO: Bret Forrester/Pat Leach
Tacoma Power
3628 South 35th Street
Tacoma, WA 98409-3192
FROM: Maggie Buckley
Scott Swarts
SUBJECT: SEPA Exemption for Geotechnical Exploration of the Potlatch Transmission Line
'Towers
PROJECT: Potlatch'Fransmission Line
PROJECT NO.: EPSY0000-0001
COPIES: File
This memorandum serves as documentation of exemption from the State Environmental Policy Act
(SEPA) for geotechnical explorations of the Potlatch Transmission Line crossing in North Bay,Mason
County.The proposed activities are summarized below, followed by a brief discussion of the
recommended SEPA exemption.
The substrate near two sets of transmission towers in North Bay will be investigated by drilling three
holes approximately 100 feet deep. One hole will be drilled near each tower and a third will be drilled
between both towers.The borings will be completed using a barge with a truck-mounted drilling rig.The
barge will be launched at the public boat ramp in Allyn, Washington.The boring depth will be
approximately 100 feet below the mudline and the borehole diameter will be approximately 8 inches.The
estimated duration is one week and drilling hours will be subject to tidal variations.
'n environment
Several measures will be Taken to avoid and minimize potential impacts to the surrounds
I p g
during the proposed explorations. A Spill Prevention Control and Countermeasures Plan will be
developed and implemented to ensure that there will be no discharge of oil, firels,or chemicals into
surface waters or onto land where there is a potential for reentry into surface waters. Best Management
Practices will be installed according to Washington State Department of Ecology(Ecology)standards and
will be inspected and maintained throughout the life of the project. No pollutants are expected to be
discharged into the aquatic environment during sampling. After drilling is complete,the boreholes will be
backtilled in accordance with Ecology standards.The proposed activities require Hydraulic Project
Approval from the Washington Department of Fish and Wildlife and a Section 10 Permit from the U.S.
Army Corps of Engineers. As such,the activities will undergo thorough environmental review from both
state and federal resource agencies.
415-II8th Avenue SE Bellevue wishingson 913005-3518 'relephone:425.519.6500 facsimile:425.519.5361
May 22
Page 2
According to RCW 43.21 C.110,the types of actions that are considered categorically exempt from SEPA
are"limited to those types which are not major actions significantly affecting the quality of the
environment."Washington Administrative Code(WAC) 197-11-800 identifies specific activities which
are considered exempt from SEPA. As identified in Section(17)of the WAC, exemptions include:
"Ltfornration collection and research. Basic data collection, research, resource evaluation,
requests for proposals(RFPs), and the conceptual planning of proposals shall be exempt. These
may be strictly for hijbrrnation-gathering, or as part of a study leading to a proposal that has not
yet been approved, adopted or fimded;this exemption does not include any agency action that
commits the agency to proceed with such a proposal. (Also see WAC 197-11-070.)"
The proposed geotechnical explorations will provide supporting data for a geotechnical report and
foundation analysis of the existing towers.Therefore,the explorations fall within the parameters of
"information collection and research"as outlined in Section(17)of WAC 197-11-800.Section(3)
provides additional support for the SEPA exemption,encompassing minor repair or replacement of public
or private facilities(including utilities) undertaken wholly or in part on lands covered by water.The
proposed explorations as described above are expected to be less intrusive on the environment than the
replacement of a piling,ramp,or float,as referenced in Section(3)of WAC 197-11-800.
Based upon the intent of RCW 43.21 C.110,the proposed borings are not considered major actions
significantly affecting the quality of the environment and satisfy the SEPA exemption criteria per WAC
197-11-800(17)as information collection and research.
Please contact me at(425)586-9792 if additional information is needed in support of the recommended
exemption.
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WAC 197-11-960 Environmental checklist.
ENVIRONMENTAL CHECKLIST
Purpose of checklist:
The State Environmental Policy Act(SEPA),chapter 43.21C RCW,requires all governmental agencies to consider the
environmental impacts of a proposal before making decisions. An environmental impact statement(EIS)must be prepared for all
proposals with probable significant adverse impacts on the quality of the environment. The purpose of this checklist is to provide
information to help you and the agency identify impacts from your proposal(and to reduce or avoid impacts from the proposal,if
it can be done)and to help the agency decide whether an EIS is required.
Instructions for applicants:
This environmental checklist asks you to describe some basic information about your proposal. Governmental agencies
use this checklist to determine whether the environmental impacts of your proposal are significant, requiring preparation of an
EIS. Answer the questions briefly,with the most precise information known,or give the best description you can.
You must answer each question accurately and carefully,to the best of your knowledge. In most cases,you should be
able to answer the questions from your own observations or project plans without the need to hire experts. If you really do not
know the answer,or if a question does not apply to your proposal,write"do not know"or"does not apply." Complete answers to
the questions now may avoid unnecessary delays later.
Some questions ask about governmental regulations, such as zoning, shoreline, and landmark designations. Answer
these questions if you can. If you have problems,the governmental agencies can assist you.
The checklist questions apply to all parts of your proposal, even if you plan to do them over a period of time or on
different parcels of land. Attach any additional information that will help describe your proposal or its environmental effects.
The agency to which you submit this checklist may ask you to explain your answers or provide additional information reasonably
related to determining if there may be significant adverse impact.
Use of checklist for nonproject proposals:
Complete this checklist for nonproject proposals, even though questions may be answered "does not apply." IN
ADDITION,complete the SUPPLEMENTAL SHEET FOR NONPROJECT ACTIONS(part D).
For nonproject actions,the references in the checklist to the words "project," "applicant," and"property or site" should
be read as"proposal,""proposer,"and"affected geographic area,"respectively.
A. BACKGROUND
1. Name of proposed project,if applicable:
Tacoma Power Potlatch Transmission Line—North Bay Geotechnical Investigation
2. Name of applicant:
City of Tacoma, Department of Public Utilities, Light Division (Tacoma Power)
3. Address and phone number of applicant and contact person:
3628 South 35ih Street,Tacoma,WA 98409
Contact: Pat Leach, Principal Engineer
4. Date checklist prepared: May 21, 2009
5. Agency requesting checklist: N/A
6. Proposed timing or schedule(including phasing,if applicable):August or September 2009
7. Do you have any plans for future additions, expansion, or further activity related to or connected with this proposal? If yes,
explain.
Yes,the proposed activity is a preliminary investigation for a possible transmission line tower replacement.
8. List any environmental information you know about that has been prepared, or will be prepared, directly related to this
proposal.
A"No Effect" letter for ESA Section 7 consultation.
9. Do you know whether applications are pending for governmental approvals of other proposals directly affecting the property
covered by your proposal? If yes,explain.
None currently pending.
10. List any government approvals or permits that will be needed for your proposal,if known.
Corps 404 Nationwide Permit and WDFW Hydraulic Project Approval.
11. Give brief, complete description of your proposal, including the proposed uses and the size of the project and site. There are
several questions later in this checklist that ask you to describe certain aspects of your proposal. You do not need to repeat those
answers on this page. (Lead agencies may modify this form to include additional specific information on project description.)
The proposed geotechnical investigation includes three drilled borings along Tacoma Power's Potlatch
Transmission line over North Bay in south Puget Sound. The borings will be completed using a barge
with a truck mounted drilling rig. The barge is approximately 35 feet long by 20 feet wide. The barge will
be launched at the public boat ramp in Allyn. The boring depth will be aPproximatelY100 feet below the
mudline.
The borings will be drilled using mud-rotary techniques. Drilling fluids will be bentonite, which lubricate
and help reduce equipment ware. The bore hole diameter will be approximately eight inches. The drilling
fluids, drill head, and drill rods will be contained within a continuous 12-inch-diameter steel casing that
extends from the barge to below the mudline.
The drilling will be conducted by lowering a 2-inch-diameter split spoon sampler to the bottom of the 8-
inch bore hole, and driving the sampler 18 inches into the soil. The sampler is driven using a 140-pound
hammer, free-falling 30 inches. The hammer is operated by an automatic trip mechanism operating on the
drill rig (i.e. auto hammer).
Drilling activities will result in removal of approximately 35 cubic feet of substrate from each boring (105
cubic feet total). Each boring hole will displace approximately 0.35 square feet of substrate per hole (plan
view). After boring is complete, the bore hole will be backfilled in accordance with Washington State
Department of Ecology (Ecology) standards with bentonite chips, and all drilling equipment will be
retrieved and moved to the next drilling location. The drill cuttings will be drummed and disposed of off
site. When the last boring is complete, the drill rig and associated equipment will be removed from the
site.
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12. Location of the proposal. Give sufficient information for a person to understand the precise location of your proposed
project, including a street address, if any, and section, township, and range, if known. If a proposal would occur over a range of
area, provide the range or boundaries of the site(s). Provide a legal description, site plan, vicinity map, and topographic map, if
reasonably available. While you should submit any plans required by the agency, you are not required to duplicate maps or
detailed plans submitted with any permit applications related to this checklist.
The project area is located in North Bay, which is at the northern tip of Case Inlet in southern Puget
Sound, Mason County,Washington.
CATEGORICAL EXEMPT STATUS
This project is categorically exempt from SEPA per WAC 197-11-800 as demonstrated in the attached
document prepared by David Evans and Associates, Inc.
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