HomeMy WebLinkAbout88-00 - Ord. Amending County Resource Ordinance ORDINANCE NUMBER ss-oo
AMENDMENTS TO THE MASON COUNTY RESOURCE ORDINANCE
AN ORDINANCE amending the the Mason County resource Ordinance regulations which apply
to Geologically Hazardous Areas . These are Section 17 . 01 . 100 Landslide Hazard Areas, Section
17 . 01 . 102 Seismic Hazard Areas, and Section 17 . 01 . 104 Erosion Hazard Areas , under the authority
of Chapters 36 . 70 and 36 . 70A RCW .
WI-IEREAS , the Board of County Commissioners held a public hearing on August 29 , 2000 , to
consider the recommendations of the Planning Commission , the Mason County Department of
Planning and citizens on the proposed amendments ;
WHEREAS , the Mason County Planning Commission formulated its recommendations after a
public hearing on August 14 , 2000 , and approved findings of fact ;
WHEREAS , these hearings were duly advertised public hearings ;
WHEREAS , these amendments are intended to comply with the March 22 , 2000 , Order of the
Western Washington Growth Management Hearings Board , Case No . 95 -02 -0073 ;
WHEREAS , the Mason County Board of County Commissioners formulated its decision after the
public hearing and has approved findings of fact to support its decision as ATTACHMENT B ;
NOW , THEREFORE, BE IT HEREBY ORDAINED , that the Board of County Commissioners
of Mason County hereby approves and ADOPTS the amended sections of the Mason County
Resource Ordinance , as amended , as described by ATTACHMENT A .
DATED this 29th day of August , 2000 .
Board of County Commissioners
Mason County , Washington
ATTEST :
John A . Bolender , Chair Clerk of the Board
Mary Jpad , Com 'ne PP OVED AS TO FORM :
t
Cynthi D . Olsen , Commissioner Prosecuting Attorney
ORDINANCE #88mOO
ATTACHMENT - PAGE 1
17 . 0 . 0 LANDSLIDE
The purpose of the Landslide Hazard Section is to identify areas that present
potential dangers to public health and safety , to prevent the acceleration of
natural geological hazards , to address off site environmental impacts , and to
neutralize the risk to the property owner or adjacent property owners from
development activities .
Except for the exceptions listed below , development in or near landslide hazard
areas requires a permit and the professional preparation of a geotechnical report or
geological assessment to determine under what conditions the development may
proceed at a reasonable risk . All development applications are reviewed to
determine if they are likely to be in or near a landslide hazard area .
® Landslide hazard areas are described in A .
® The designation of landslide hazard areas is done in B .
• Activities exempt from these requirements are described in CA 1 . and others
are listed in section 17 . 01 . 130 of the Resource Ordinance .
• Activities requiring permits are described in C . 2 .
• Standard requirements for certain activities are contained in D .
• When a geotechnical report or geological assessment is required is
determined in E 1 and 2 .
• The standards for a geotechical report and geological assessment are
contained in E . 3 , 4 , 5 , and 6 .
• The general review standard for approval of a permit is in E . 7 .
• Notice of the risks inherent in development in a landslide hazard area is
required for the applicant and future property owners in F .
A . CLASSIFICATION
1 . The following shall be classified as Landslide Hazard Areas :
a . Areas with any indications of earth movement such as debris
slides , earthflows , slumps and rock falls ( see figure F . 100 ) .
b . Areas with artificial oversteepened or unengineered slopes , i . e .
cuts or fills .
c . Areas with slopes containing soft or potentially liquefiable soils .
d . Areas oversteepened or otherwise unstable as a result of
stream incision , stream bank erosion , and undercutting by
wave action .
ORDINANCE 8 - 0
ATTACHMENT A - PAGE 2
e . Slopes greater than 15 % ( 8 . 5 degrees ) and having the
following :
i . Hillsides intersecting geologic contacts with a relatively
permeable sediment overlying a relatively impermeable
sediment or bedrock ( e . g . sand overlying clay ) ; and
ii . Springs or groundwater seepage .
f . Any area with a slope of forty percent or steeper and with a
vertical relief of ten or more feet except areas composed of
consolidated rock . A slope is delineated by establishing its toe
and top and measured by averaging the inclination over at least
ten feet of vertical relief .
2 . The following information may be used as a guide by the County to
indicate areas that have a higher likelihood of meeting the
classification criteria above .
a . The areas identified on the Mason County Soil Survey Map as
having slopes greater than 15 % .
b . The areas identified on the Coastal Zone Atlas , Volume 9 , of
Mason County , Washington as :
i . Unstable - " U '
ii . Unstable Old Slides - " UOS "
iii . Unstable Recent Slides - " URS "
c . The areas identified as Class 2 , 3 , 4 , or 5 of the map of
" Relative Slope Stability of the Southern Hood Canal Area ,
Washington " , Washington State Department of Natural
Resources , Division of Earth Resources , 1977 .
B . DESIGNATION
1 . Lands of Mason County classified as Landslide Hazard Areas are
hereby designated , under RCW 36 . 70A . 060 and RCW 36 . 70A . 170 ,
as critical areas requiring immediate protection from incompatible land
uses .
2 . Upon an application for development on either mapped or unmapped
lands , the Director shall determine if a hazard exists on a particular
site based on :
ORDINANCE 88 - 0
ATTACHMENT A on PAGE 3
a . Information supplied by the applicant in the form of a
geotechnical report or geological assessment ,
b . Actual physical observation of the site ,
c . Existing County Hazard Area maps , or
d . Other means determined to be appropriate .
If the presence of a hazard is determined , the boundaries of the
hazard and associated buffers shall then be delineated ( top , both
sides , and toe ) on a geologic map of the site .
Co LAND USES
1 . Exempt Uses
a . The growing and harvesting of timber , forest products and
associated management activities in accordance with the
Washington Forest Practices Act of 1974 , as amended , and
regulations adopted pursuant thereto ; including , but not limited
to , road construction and maintenance , aerial operations ;
applications of fertilizers and pesticides , helispots ; and other
uses specific to growing and harvesting timber forest products
and management activities , except those Forest Practices
designated, as " Class IV - General Forest Practices " under the
authority of the " Washington State Forest Practices Act Rules
and Regulations WAC 222 - 1 & 030 ;
b . Those activities and uses conducted pursuant to the
Washington State Surface Mining Act , RCW 78 . 44 and its
Rules and Regulations , where State law specifically exempts
local authority ;
c . Existing and ongoing agriculture , aquaculture , floriculture ,
horticulture , general farming , dairy operating under best
management practices ( BMP ) of the Washington State
Department of Ecology ' s Storm Water , Water Quality ,
Hazardous Waste , Wetland , and Solid Waste Program and BMP
from the Departments of Health , Agriculture , Transportation ,
and State Conservation District Office .
ORDINANCE 88 - 00
ATTACHMENT A - PAGE 4
2 . Permit Required Uses
Permits are required for all new construction , grading , land clearing ,
and other uses subject to Section 17 . 01 . 050 , and any Class IV
Conversion Permit pursuant to the State Forest Practices Act which
involves conversion to a Permit Required Use , and are within a
Landslide Hazard Area or its buffer . Permit Required Use may require
a Geotechnical Report , see Section 17 . 01 . 100 . E .
D . DEVELOPMENT STANDARDS
Any land use on Landslide Hazard Areas or their buffers shall conform to the
following standards :
1 . Grading
a . No grading shall be performed in landslide hazard areas prior to
obtaining a grading permit subject to approval , by the Director ,
based on recommendations contained in the geotechnical report
with slope stability , drainage , erosion control and grading
recommendations .
b . Clearing during grading shall be limited to the area of the
approved development .
c . No fill , dead vegetation ( slash /stumps ) , or other foreign
material shall be placed within a Landslide Hazard Area ; with
the exception of engineered compacted fill for construction of
buttresses for landslide stabilization which shall be in
accordance with recommendations specified in a Geotechnical
Report .
2 . Land Clearing
a . Within this section , " Land Clearing " is defined as the cutting or
harvesting of trees or the removing or cutting of vegetation so
as to expose the soil and which is not otherwise exempt from
this section .
ORDINANCE 88 = 00
ATTACHMENT = PAGE
b . Land Clearing in Landslide Hazard Areas or their buffers is
permitted when it is consistent with the recommendation and
plans contained in the Geotechnical Report and development
approval
c . If there is no Geotechnical Report for the site , land clearing is
not permitted ° however removal of danger trees , selected
removal for viewing purposes of trees less than 6 inches dbh
( diameter at breast height) and trimming or pruning of existing
trees and vegetation is allowed with the qualifications cited
herein . Danger trees shall be identified with the
recommendation of a member of the Association of Consulting
Foresters of America , an arborist certified by the International
Society of Arboriculture , or with the recommendation of a
person qualified to prepare a geotechnical report if removing
trees for slope stalization purposes . Removal of trees less
than 6 inches dbh shall be limited to less than 2 percent of the
total number of trees of that size or larger in the hazard area .
Removal of multiple trees in a concentrated area , i . e . within a
distance of 25 feet of each other , shall be accompanied by
replacement by deep rooting native shrubs or other vegetation
that serve similar moisture and erosion protective functions to
that provided by the removed trees . Trimming and pruning shall
be accomplished in accordance with pruning standards of the
International Society of Arboriculture , as published in " ANSI
A300 - 95 " or subsequent updated versions in order to minimize
the potential for long term damage to the trees .
d . Removal of selected trees and ground cover is allowed without
a permit for the purpose of surveying and geotechnical
exploration activities that do not involve grading , provided that
re - vegetation of the disturbed areas occurs immediately
afterward .
e . Land clearing for which a permit has been obtained shall not be
allowed during the wet season , i . e . from November 1 through
May 1 , unless special provisions for wet season erosion and
landslide protection have been addressed in the Geotechnical
Report and approved by the Director .
ORDINANCE = 00
ATTACHMENT A AGE
3 . Drainage
a . Surface drainage , including downspouts and runoff from paved
or unpaved surfaces up slope , shall not be directed onto or
within 50 feet above or onto the face of a Landslide Hazard
Area or its associated buffer . If drainage must be discharged
from the top of a Landslide Hazard Area to below its toe , it
shall be collected above the top and directed to below the toe
by tight line drain and provided with an energy dissipating
device at the toe .
b . Stormwater retention and detention systems , including
percolation systems utilizing buried pipe or french drain , are
prohibited unless a licensed civil engineer certifies appropriate
mitigation measures .
c . Erosion shall be controlled as provided in the Mason County
Stormwater Management Ordinance and any geotechnical
report or geological assessment prepared for the site .
4 . Sewage Collection /Treatment Systems
Sewage collection and treatment systems shall be located outside of
the Landslide Hazard Areas and associated buffers , unless an
approved geotechnical report specifies appropriate mitigation
measures . See Section 17 . 01 . 100 . E .
5 . Subdivision Design and Lot Size
For the purpose of determining lot sizes under Title 16 of the Mason
County Code , and other county regulatory requirements , the Director
shall review available information and required Geotechnical Reports
or Geological Assessments under Section 17 . 01 . 100 . E , and make a
decision on a case - by - case basis based on the reports . To avoid
impacts to anadromous fisheries and fish habitat , land divisions ,
( short plats , subdivisions , and large lot divisions ) shall not be
approved unless :
a . No improvements or construction shall be within fish and
wildlife habitat conservation areas , wetlands , or their buffers ,
provided that necessary water or wetland crossings or
encroachments approved pursuant to other sections of the
ORDINANCE - 0
ATTACHMENT - PAGE 7
Mason County Resource Ordinance or other county regulations
may be permitted for roads and utilities .
b . All lots must have designated building areas on which
structures may be safely located without the requirement for
bulkheading , bank protection or other structures that encroach
on fish and wildlife habitat conservation areas , wetlands , or
their buffers . Future buildings are to be limited to such
designated areas .
The number , size , or configuration of lots may be changed as a
condition of approval to meet this requirement .
6 . Buffers
a . A 50 foot ( 15 . 25 meter) buffer of vegetation is required around
the Landslide Hazard Area .
b . Upon finding substantial evidence that the proposed
development is to be located near or within a hazardous area ,
the Director may require a Geotechnical Report or Geological
Assessment pursuant to Section 17 . 01 . 100 . E . Based on the
results of the Geotechnical Report or Geological Assessment ,
the Director may increase the buffer .
c . An application may be made to reduce the buffer for the
purpose of constructing a single family residence on a lot
existing or vested by December 6 , 1996 . Notice of application
for the reduction of the buffer shall be made as provided in
Section 15 . 07 . 010 of the Mason County Development Code
( which specifies how notice is sent to adjacent property
owners and posted on the site ) . The Director shall approve
such a reduction only on finding that the approval is
conditioned as necessary to be consistent with the
recommendations contained within the Geotechnical Report or
Geological Assessment ( described in Sections 17 . 01 . 100 . E . )
and on finding that impacts to anadromous fish or their habitat
or to fish and wildlife habitat conservations areas shall be
avoided or mitigated as detailed in an approved Habitat
Management Plan ( described in Section 17 . 01 . 1 10 . )
7 . Bulkheads and Bank Protection
ORDINANCE #88 = 00
ATTACHMENT A = PAGE 8
Bulkheads and bank protections , along with related fill , constructed
for landslide stabilization measures approved under the Shoreline
Master Program or the Fish and Wildlife Habitat Conservation Area
regulations , shall be consistent with recommendations specified in a
Geotechnical Report .
8 . Residential Densities and Floor Area Ratios
The landslide hazard area and its buffer shall be counted in calculating
the number of dwelling units ( determined by the size of the site and
residential density allowed ) or the area of non - residential building
( determined by the size of the site and the floor area ratio allowed )
that may be built on the site ; provided that :
a . the development is outside of the landslide hazard area or its
buffer , and
ba the development is able to comply with all county regulations
without encroaching on the landslide hazard area or its buffer .
Clustering of residential development away from landslide hazard area
and its buffer may receive a density bonus if performed meeting the
design requirements contained in Chapter 16 . 22 , Mason County
Code .
E . GEOTECHNICAL REPORT
1 . Applicability
Every application for development within a Landslide Hazard Area or
its buffer or within 200 feet ( 60 . 96 meters ) of the buffer shall meet
the standards of Section 17 . 01 . 1OO . D and shall require either a
Geological Assessment or a Geotechnical Report , or both , in
accordance with the following guidance :
Category a . Areas with slopes greater than 40 percent ( 21 . 8 degrees )
will require an Geotechnical Report .
Category b . Areas with any visible signs of earth movement such as
debris slides , earthflows , slumps and rockfalls , or areas
within 200 feet of previously mapped or recorded
landslides will require a Geotechnical Report .
ORDINANCE #8 = 00
ATTACHMENT A - PAGE 9
Category c . Areas within 100 feet of oversteepened or otherwise
potentially unstable slopes as a result of stream incision ,
stream bank erosion , and undercutting by wave action
will require an Geotechnical Report .
Category d . Areas with slopes between 15 percent ( 8 . 5 degrees ) and 40
percent ( 21 . 8 degrees ) will require a Geological
Assessment , and may further require a Geotechnical
Report upon analysis of the following factors by the
Director .
( 1 ) Lot size and use ;
( 2 ) Overall height of slope and maximum planned cut or fill
( requires a grading plan ) ;
( 3 ) Soil types and history of sliding in the vicinity ( from the
Geological Assessment ) ;
( 4 ) Groundwater conditions , including depth to water and
quantity of surface seepage (from the Geological
Assessment) ;
( 5 ) Approximate depth to hard or dense competent soil , e . g .
glacial till or outwash sand ( from the Geological
Assessment) ;
( 6 ) Impervious surfaces and drainage schemes ( requires
development/grading plan ) ;
( 7 ) Wastewater treatment ( requires on - site sewage disposal
system approval from Mason County Department of
Health ) ;
( 8 ) Potential off- site impacts , including adjacent properties ,
roadways , etc . ( requires environmental statement
dependant on scope of project ) .
2 . Waiver of Geotechnical Report
The Director may waive the requirement for the Geotechnical Report
for Category c and d sites upon a written finding in the Geological
Assessment that the potential for landslide activity is low and that the
proposed development would not cause significant adverse impacts ,
or that there is adequate geological information available on the area
proposed for development to determine the impacts of the proposed
development and appropriate mitigating measures .
3 . Qualifications of Preparer
The Geologic Assessment shall be prepared at the discretion of the
Director by either a licensed civil engineer with specialized knowledge
of geotechnical /geological engineering or a practicing engineering
geologist with special knowledge of the local conditions . The
ORDINANCE -
ATTACHMENT A - PAGE 10
preparer shall have at least three years of experience in landslide
assessment and shall submit a statement of qualifications with the
assessment or report , unless they have been previously determined to
be qualified by Mason County . The Geotechnical Report shall be
prepared at the discretion of the Director by a licensed civil engineer
with specialized knowledge of geotechnical /geological engineering .
The Geotechnical Report may also be prepared by a practicing
engineering geologist with special knowledge of the local conditions ,
provided the work is performed under the supervision of a licensed
civil engineer who will stamp the report and attest to the competency
of the engineering geologist to perform landslide evaluations in
accordance with the prevailing standard of practice .
4 . Content of the Geological Assessment
A Geological Assessment shall include but not be limited to the
following :
( 1 ) A discussion of geologic conditions in the general vicinity of the
project , and specific soil types at the project site . Soil type
identifications shall be consistent with terminology used in the
Coastal Zone Atlas ( Washington Department of Natural Resources ,
1980 ) or in applicable U . S . Geologic Survey maps ( e . g . Geological
Map of North Central Mason County , by R . J . Carson , 1976 , U . S .
Geologic Survey OFR 76 - 2 ) . Use of Soil Conservation Service soil
layer terminology is considered inappropriate for this assessment .
( 2 ) A discussion of the ground water conditions at the site , including the
depth to water and the quantity of surface seepage .
( 3 ) The approximate depth to hard or dense competent soil , e . g . glacial
till or outwash sand .
( 4 ) A discussion of the history of landslide activity in the vicinity , as
available in the Coastal Zone Atlas , the map of " Relative Slope
Stability of the Southern Hood Canal Area , Washington " by M . Smith
and R . J . Carson , 1977 , and the landslide records on file with the
Mason County Department of Community Development .
( 5 ) An opinion on the potential for landslide activity at the site in light of
the proposed development .
5 . Content of a Geotechnical Report
A Geotechnical Report shall include but not be limited to the following :
( 1 ) A discussion of general geologic conditions , specific soil types ,
ground water conditions and history of landslide activity in the vicinity
as required for the Geologic Assessment described above .
( 2 ) A site plan which identifies the important development and geologic
features .
ORDINANCE # 8 & 00
ATTACHMENT APAGE 1
( 3 ) Locations and logs of exploratory holes or probes .
( 4 ) A minimum of one cross section at a scale which adequately depicts
the subsurface profile , and which incorporates the details of proposed
grade changes .
( 5 ) A description and results of slope stability analyses performed for
both static and seismic loading conditions .
( 6 ) Appropriate restrictions on placement of drainage features , septic
drain fields and compacted fills and footings , including recommended
setbacks from shoreline bluffs and the tops of other slopes on the
property .
( 7 ) A detailed clearing and grading plan which specifically identifies
vegetation to be removed , a schedule for vegetation removal and
replanting , and the method of vegetation removal .
( 8 ) A detailed temporary erosion control plan which identifies the specific
mitigating measures to be implemented during construction to protect
the slope from erosion , landslides and harmful construction methods .
( 9 ) An analysis of both on - site and off- site impacts of the proposed
development .
( 10 ) Specifications of final development conditions such as , vegetative
management , drainage , erosion control , and buffer widths .
6 . Applicable Standards
Geological Assessments and Geotechnical Reports shall be prepared
using terminology , descriptions , evaluation methods and mitigation
approaches that reflect the current standard of care for practitioners
in the field of geologic hazards . The standard of care shall be
considered to be represented by , but not limited to , Turner , A . K . and
Schuster , R . L . ( 1996 ; " Landslides , Investigation and Mitigation " ;
Transportation Research Board Special Report 247 , National Academy
Press , Washington DC . ) for classification , analysis and conceptual
mitigation of landslides ; Washington Department of Ecology ( 1993 ;
" Slope Stabilization and Erosion Control Using Vegetation , A Manual
of Practice For Coastal Property Owners " , Publication No . 93 - 30 ,
Olympia , WA , and " Vegetation Management : A Guide For Puget
Sound Bluff Property Owners " , Publication No . 93 - 31 , Olympia , WA )
for vegetation management and it use in slope stabilization and
erosion protection ; and Washington Department of Ecology ( 1995 ;
" Surface Water and Groundwater on Coastal Bluffs " , Publication No .
95 - 107 , Olympia , WA ) for water and drainage management and its
use in slope stabilization and erosion protection .
ORDINANCE 88 -
ATTACHMENT APAGE 12
7e . Administrative Determination
Any area in which the Geotechnical report or geological assessment
indicates the presence of landslide hazards shall not be subjected to
development unless the report demonstrates conclusively that the
hazards can be overcome , and that the development meets all
standards in Section 17 . 01 . 100 . D . Hazards must be overcome in
such a manner as to prevent harm to property and public health and
safety , and to assure no significant adverse environmental impact .
Impacts to anadromous fish or their habitat or to fish and wildlife
habitat conservations areas shall be avoided or mitigated as detailed
in an approved Habitat Management Plan , as described in Section
17 . 01 . 110 . The Director may submit either the Geologic Assessment
or the Geotechnical Report to an outside agency with geotechnical
expertise or to a geotechnical consultant for third party peer review
prior to issuing a ruling on the project .
F . APPLICANT HOLD HARMLESS STATEMENT
The property owner shall be required to acknowledge in writing the
risks inherent in developing in a geologic hazard area , accept the
responsibility of any adverse affects which may occur to the subject
property or other properties as a result of the development , and agree
to convey the knowledge of this risk to persons purchasing the site .
mORDINANCE
OO
ATTACHMENT APAGE 13
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ORDINANCE 8 - 0
ATTACHMENT A - PAGE 14
17m0lo "102 SEISMIC HAZARD AREAS
The purpose of the Seismic Hazard Section is to identify areas that present
potential dangers to public health and safety , and to prevent the acceleration of
manmade and natural geological hazards , and to neutralize the risk to the property
owner or adjacent properties from development activities . Types of Seismic
Hazards include : Surface Faulting ; Ground Shaking ; Earthquake - related ground
failure and landslides ; Lateral Spreading ; Liquefication ; Lurch Cracks ; Rockfalls ;
Differential Settlement ; Regional Uplift ; Seiches ; and /or Tsunamis . These are
defined under Seismic Hazard Areas in Section 17 . 01 . 240 .
A . CLASSIFICATION
The following shall be classified as Seismic Hazard Areas :
1 . Areas susceptible to ground failure including the following :
a . Mapped geologic faults until proven inactive ,
b . Deep road fills and areas of poorly compacted artificial fill ;
c . Areas with artificially steepened slopes ( i . e . old gravel pits ) ;
d . Postglacial stream , lake or beach sediments ;
e . River deltas ;
f . Areas designated as potential Landslide Hazard Areas ,
go bluff areas ; and
2 . The following criteria may be used as a guide by the County to
indicate areas that have a higher likelihood of meeting the
classification criteria above :
a . Areas identified on the Coastal Zone Atlas of Washington , Volume 9 ,
Mason County as Af , Qa1 , Qa2 , Qvc , Qls , Qos and Qp .
b . Areas identified on the Mason County Soil Survey Map as having
slopes greater than 15 percent .
ORDINANCE 88 -
ATTACHMENT A - PAGE 15
c . Faults identified on " Map Showing Known or Suspected Faults With
Quaternary Displacement in the Pacific Northwest " , A . M . Rogers , T . J .
Walsh , W . J . Kockelman and G . R . Priest , US Geologic Survey , 1996 ;
or described in " Active Faulting Investigations on the Canyon River
Fault , Southern Olympic Range , Washington " , T . J . Walsh and K . G .
Neal , U . S . Geologic Survey , 1997 .
B . DESIGNATION
Lands of Mason County meeting the criteria for Seismic Hazard Areas are
hereby designated , under RCW 36 . 70A . 060 and RCW 36 . 70A . 170 , as
critical areas .
C . LAND USES
All uses and activities within Seismic Hazard Areas are subject to the
development standards of this Section .
D . DEVELOPMENT STANDARDS
1 . Development in Seismic Hazard Areas must be in compliance with
Section 17 . 01 . 050 .
2 . Development within Landslide Hazard Areas must be in compliance
with Section 17 . 01 . 100 .
3 . Location of Buildings and Facilities
Upon application for a Building Permit , if the Director finds that the
proposed development is within a Seismic Hazard Area , the County
shall notify the applicant and indicate that the potential effects of
seismic activity shall be considered and that Geologic Assessment or
Geotechnical Report which addresses the seismic hazard shall be
required . Requirements of the Geologic Assessment and Geotecnical
Report and the preparer shall be as detailed in Section 17 . 01 . 100 E .
a . The Geologic Assessment or Geotecnical Report shall include a
description of the geology of the site , conclusions and
recommendations regarding the effect of geological conditions
on the proposed development , and opinions and
recommendations for compensating for the seismic hazards
present .
ORDINANCE #88 =00
ATTACHMENT APAGE 16
b . The County shall take the potential seismic effects into
consideration when reviewing the proposal under SEPA and
may include an alternative site analysis and recommendations .
4 . Approval of development in Seismic Hazard Areas shall not be issued
unless a Geological Assessment or Geotechnical Report demonstrates
conclusively that the hazards can be overcome . Hazards must be
overcome in such a manner as to prevent harm to public health ,
safety , and property and to minimize environmental impact . Impacts
to anadromous fish or their habitat or to fish and wildlife habitat
conservations areas must be avoided or mitigated as detailed in an
approved Habitat Management Plan , as described in Section
17 . 01 . 110 . The Director may submit the Report to an outside agency
with geotechnical expertise or to a geotechnical consultant for third
party peer review prior, to issuing a ruling on the project at the
applicants expense .
5 . New developments within Seismic Hazard Areas shall be designed in
accordance with applicable provisions of the 1997 Uniform Building
Code ( UBC ) including consideration of the ground motions associated
with a 475 year return period seismic event for Seismic Zone 3 and
the liquefaction and soil strength loss that may occur during that
event . Components of the new development that are critical to health
and safety , such as roadways and bridges , that may not be directly
addressed by the UBC shall be designed taking into consideration the
same ground motions and their possible effects as identified in the
UBC for structures .
ORDINANCE B - O
ATTACHMENT A - PAGE 17
17m01104 EROSION HAZARD AREAS
The purpose of the Erosion Hazard Section is to identify areas that present
potential dangers to public health and safety , and to prevent the acceleration of
natural geological hazards , and to neutralize the risk to the property owner from
development activities .
A . CLASSIFICATION
The following shall be classified as Erosion Hazard Areas .
Areas in Mason County underlain by soils which are subject to severe
erosion when disturbed . Such soils include , but are not limited to , those for
which potential for erosion is identified in the Soil Survey of Mason County ,
USDA Soil Conservation Service , 1960 , or any subsequent revisions or
addition to this source . These soils include , but are not limited to , any
occurrence of River Wash ( " Ra " ) or Coastal Beaches ( " Cg " ) and the
following when they occur on slopes 15 % or steeper .
a . Alderwood gravelly sandy loam ( " Ac " and " Ad " )
b . Cloquallum silt loam ( " Cd " )
c . Harstine gravelly sandy loam ( " Hb " )
d . Kitsap silt loam ( " Kc " )
B . DESIGNATION
The lands of Mason County meeting the criteria for Erosion Hazard Areas
and are classified as such are hereby designated , under RCW 36 . 70A . 060
and RCW 36 . 70A . 170 , as critical areas .
C . LAND USES
All uses and activities within Erosion Hazard Areas are subject to the
development standards of this Section .
D . DEVELOPMENT STANDARDS
Any land use on Erosion Hazard Areas shall conform to the following
standards :
1 . Development in Erosion Hazard Areas must be in compliance with
Section 17 . 01 . 050 , and standards and requirements in Section
17 . 01 . 100 of this Chapter .
ORDINANCE # 8 = 00
ATTACHMENT A - PAGE 18
2 . No land clearing or grading activities shall be performed in an Erosion
Hazard Area prior to obtaining a grading permit , subject to approval
by the Director , based on the recommendations contained in the
Geotechnical Report .
3 . Upon application for a Building Permit , if the Director finds that the
proposed development is within an Erosion Hazard Area , the County
shall require the applicant to submit a Soil Erosion and Sediment
Control Plan . The Plan may be included in the Geotechnical Report or
separately prepared by a Professional Engineer licensed in the State of
Washington . The Soil Erosion and Sediment Control Plan shall
specifically and realistically identify temporary and permanent
measures of erosion control .
4 . Wet Season Operations : Clearing on an erosion hazard area shall be
limited to the period between May 1 - November 1 . If wet season
operations are sought , the applicant shall provide erosion and
sedimentation control plan prepared by a professional engineer
licensed in the State of Washington that specifically and realistically
identifies methods of erosion control for wet weather conditions .
5 . The Soil Erosion and Sediment Control Plan shall provide for
protection of the development area and disturbed surfaces not
involved in the immediate development operation using Best
Management Practices ( BMP ) such as sediment traps , check dams ,
stabilized construction entrances , storm inlet protection , silt fencing ,
mulching or other effective means of soil protection .
6 . Runoff from activities subject to a development permit shall be
properly controlled to prevent erosion .
7 . Continued Responsibility : It shall be the responsibility of the property
owner and the permittee to ensure that accelerated erosion does not
occur during and after the project construction . Additional
measures , beyond those specified in an approved Soil Erosion and
Sediment Control Plan , may be required by the Director as deemed
necessary to control erosion after project completion .
ORDINANCE #88=00 ATTACHMENT
Findings of Fact - Page 1
Mason County Board of Commissioners
August 29 , 2000
FINDINGS OF FACT
to
Linder consideration is a proposal to amend the county the Resource Ordinance regulations
which apply to Geologically Hazardous Areas . These are Section 17 . 01 . 100 Landslide Hazard
Areas, Section 17 . 01 . 102 Seismic Hazard Areas, and Section 17 . 01 . 104 Erosion Hazard Areas .
The amendments were intended to address the issues in the March 22 , 2000, order of the Western
Washington Growth Management Hearings Board (Hearings Board), Case #95 -2 - 0073 .
2 ®
Mason County amended its Landslide Hazard Areas section of its Resource Ordinance in
Ordinance 149 -99 . The amendments were proposed because , in the administration of the
previous regulations , it was determined that more specific requirements were needed with
respect to when a geotechnical report or geological assessment was needed , what the content of
such report was to be , and criteria to guide the discretion of the administrator . The county
retained the firm of Dames and Moore , an engineering firm with expertise in this field , and
the county incorporated the consultants recommendations into the regulations . The order of the
Hearings Board found the county ' s regulations out of compliance with the Growth
Management Act and remanded to the county the Resource Ordinance regulations which apply
to Geologically Hazardous Areas . These are Section 17 . 01 . 100 Landslide Hazard Areas ,
Section 17 . 01 . 102 Seismic Hazard Areas , and Section 17 . 01 . 104 Erosion Hazard Areas .
Sections 17 . 01 . 102 and 17 . 01 . 104 had not been amended since the (Interim) Resource
Ordinance was first adopted by Mason County on August 2 , 1993 .
3 .
After review of the order , a draft revision dated July 2000 was prepared . A State
Environmental Policy Act Determination of Nonsignificance was issued on these amendments
on July 17 , 2000 . The comment period ended July 31 , 2000 . The Department of Planning
determined that the changes to the proposal improved environmental protections and will not
cause significant adverse environmental impact .
40
Discussion
The Planning Department prepared memorandums for the Planning Commission to explain the
proposed changes to the ordinance . The first is dated July 17 , 2000 and addresses the reasons
for the changes proposed in the first draft , dated July 2000 . The second memorandum is dated
August 10 , 2000 , and addresses changes proposed in the August loth draft . The August loth
draft ordinance contains revisions intended to address comment received at the July 17th
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Findings of Fact - Page 2
Planning Commission public hearing , written comment received to date , and the
recommendations of the county ' consultants URS Dames and Moore , an engineering firm with
expertise in this field . The Planning Commission held a public hearing on July 17 , 2000 ,
which was continued until July 31 st . That public hearing was canceled , and another public
hearing was advertised and held on August 14 , 2000 . After the August 14 hearing , the
Planning Commission recommended approval of the proposed changes (with some
modification to the August loth draft) to the Board of County Commissioners .
Fin g
The Planning Commission considered the record before it , the order of the Bearings Board ,
the recommendations of its expert witness , staff, state agencies , and the public . The Planning
Commission provided proper opportunity for public comment prior to making its
recommendations .
5 .
The drafting of the proposal incorporates the best science available by relying on the comments
of state agencies , and the expert opinion of the county ' s consultant , using referenced
publications from state agencies , and other publications as cited .
6 .
The proposed regulations incorporate the best available science in the making of permit
decisions through its reliance , where appropriate , on special studies and reports prepared by
qualified technicians in project review . These include : geological assessments , geotechnical
reports , habitat management plans , and soil erosion and sediment control plans . Best available
science is also incorporated in the permit review process by standards to be used in reviews
including best management practices as published by various state agencies and other standard
publications . Tree removal , pruning or trimming must be done consistent with the direction of
expert advice through a geotechnical report or consultation with an expert applying published
standards .
7 °
Discussion
The Board of Commissioners held a public hearing on the Planning Commission
recommendations on August 29 , 2000 . The Board considered the additional testimony before
it , including : a Planning Department Memo dated August 29 , 2000 ; an Washington Office of
Community Development (formally CTED) letter dated August 28 , 2000 ; a Washington
Department of Fish and Wildlife letter dated August 28 , 2000 ; and the testimony of its
consultant Martin McCabe . Based on this information , the Board proposed a number of
changes to the planning commission recommendation . These changes required consultation
with a person qualified to prepare geotechnical reports when removing trees for slope
stabilization purposes , clarified that drainage systems are to be engineered with appropriate
mitigation , restricted the distance from the landslide hazard area at which geotecec cal
ORDINANCE #88-0 - ATTAc NT
Findings of Fact - Page 3
reports are required , clarified the text regarding standards for making administrative
determinations , and added a new classification of landslide hazards to avoid unintended effects
of earlier amendments .
Finding
The Board proposed several modification to the Planning Commission recommendations which
improve and/or clarify the ordinance with the concurrence of the expert testimony of their
consultant .
8 <
Discussion
The staff reports , consultant reports , and minutes from the Planning Commission meetings
discuss how the proposed changes address March 22 , 2000 order of the Hearings Board .
GMHB Order . 1 ) Reference, as it pertains to GHAs (Geologically Hazardous
Areas) , inclusion of BAS (best available science) used in the
Aquatic Management section of the IRO (Resource Ordinance)
The proposal has several cross references between the Aquatic Management (Fish and
Wildlife) section of the Resource Ordinance and the Geologically Hazardous sections . These
references provide for the consideration of best available science in addressing possible
impacts to the fish and wildlife habitat areas and in addressing possible geological hazards
when reviewing fish and wildlife or shoreline permits .
GMHB Order : 2) Consider appropriate densities in GHAs
Development densities in the geologically hazardous areas may be required to be reduced or
may be transferred out of the critical areas to avoid or mitigate impacts . The record also shows
that , geologically hazardous areas were considered in establishing allowed densities through
land use designations . However , it was determined not to be reasonable that all such critical
areas be avoided by the more intensive use designations because of the wide- spread nature of
the hazard and its rapid variation due to the site geology . It was also not required . It was also
noted that in order to receive the density bonuses available through performance subdivisions ,
the critical areas must be avoided by the development .
GMHB Order 3) Provide standards and definitions as discussed in the
conclusion section, e. g. , define and set standards for " minimum
soil, tree, and vegetation disturbance, " and " minimize impact
to anadromous fish "
The proposal includes additional standards and administrative guidance , including standards
and permit requirements for land clearing and other vegetation removal or trimming . Vague
language was deleted or clarified . Special consideration for anadromous fish was provided for
as discussed in Finding 8 .
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Findings of Fact - Page 4
GNIHBOrder * ) Require permits for clearing
The proposal limits land clearing and establishes standards for vegetation management . The
proposal specifies that clearing is only allowed pursuant to permitted development and consistent
with the study or report done for the site, with a permit, or according to specified standards . All
of these options provide for review using best available science .
GMHB Order * 5) Extend protection of GHAs as critical areas , with special
consideration for the needs of anadromous fish , to already-
platted lots not subject to further subdivision
The proposal addresses this in requirements that all permit approvals (which includes
development on existing lots) consider environmental impacts and avoid impacts or mitigate
for impacts to anadromous fish or their habitat or to fish and wildlife habitat conservation
areas as provided in a habitat management plan . This is further discussed below .
GMHB Order * 6 ) Remove the discretion to reduce buffer width below 50 ' . The
County has failed to include the BAS (best available science)
embodied in the evidence presented by an agency with
expertise ( DFW)
The proposal substantially modifies the section which allows buffer width reduction by
providing that best available science be used in the decision as included in a geotechnical
report or geological assessment, providing that public notice is made , and providing that
environmental impacts are avoided or mitigated as shown in a habitat management plan , which
is also based on best available science .
Finding
The proposed changes address the order of the Hearings Board ,
9 .
Discussion
The geologically hazardous areas ordinance is intended to be consider and balance the multiple
goals of the Mason County Comprehensive Plan and the Growth Management Act . By
avoiding or addressing the natural hazards , the proposed ordinance protects public health and
safety . But the proposed ordinance is also coordinated with other county regulations to remove
or minimize environmental impacts . In particular , special consideration is given to the impacts
to anadromous fish and fish habitat . To address potential cumulative impacts from future land
divisions , specific standards are included that may result in redesign of the proposed land
divisions and/or the reduction in the number of possible lots . This will limit the need for
bulkheads and bank protections that can have a more direct impact on the fish habitat . Special
consideration was also given to addressing potential impacts involving existing parcels when
considering buffer reductions and in all administrative decisions allowing development in
ORDINANCE # 8-0 - ATTACHMENT
Findings of Fact - Page 5
landslide hazard areas . Coordination with other permits and goals of the county was further
addressed by requiring that the recommendations specified in a geotechnical report be
considered during those reviews .
Critical areas , such as the geologically hazardous areas , are designated and protected in
accordance with the Growth Management Act . Development regulations , such as those under
consideration , must be consistent with and promote the goals of the GMA . The draft
harmonizes the relevant goals as follows : Restrictions on development protect the public health
and safety and protect the environment . Excessive restrictions which are not necessary for the
public purpose and/or are not based on best available science interfere with the goals of
protecting property rights , encouraging economic development , and enhancing the affordability
of housing . These regulations attempt to provide options for development and consideration of
environmental impacts in making site specific decisions based on best available science . The
regulations are intended to address public concerns caused by development and to increase the
clarity and predictability of the regulations , recognizing the complexity and the site/project
specific nature of geological hazards . This is also intended to enhance the goal of timely and
fair permitting .
The Mason County Comprehensive Plan calls for the county to adopt landslide hazard area
regulations to protect the public and to minimize the risks to property owners and adjacent
property owners from development activities . Landslide hazard areas are discussed in section 4
of Chapter IV . Policies for these areas are discussed in section 5 of Chapter III .
Finding
The proposed provisions appear to provide a proper balancing of diverse goals , public interests
and individual rights , and to provide for special consideration of the protection and
enhancement of anadromous fish . The proposal is consistent with and balances the goals of the
Growth Management Act . The proposal is consistent with and implements the Mason County
Comprehensive Plan .
The Board of Commissioners voted to adopt the changes proposed . The preceding findings
summarize the basis for that decision .
Chair , Mason County Board of Commissioners
r7
Date