ORD 2007-05 BI MUNICIPAL CODEORDINANCE 2007-OS
AN ORDINANCE of the City of Bainbridge Island,
pertaining to management of slopes identified as
geologically hazardous areas; and amending Sections
16.20.030, 16.20.040, 16.20.070 and 16.20.150 of
Chapter 16.20 of the Bainbridge Island Municipal Code
(BIMC).
WHEREAS, BIMC Chapter 16.20, the Critical Area Ordinance, regulates
activities on and adjacent to critical areas; and
WHEREAS, geologically hazardous areas are one type of critical areas
recognized in the Growth Management Act (RCW 36.70a); and
WHEREAS, on December 14, 2005, the City Council adopted Ordinance 2005-
03 amending BIMC Chapter 16.20 of the Bainbridge Municipal Code; and
WHEREAS, implementation of code revisions specific to development
regulations in geological hazardous areas requiring a variance has resulted in preventing
approval of some development projects that are consistent with the goal of protecting the
public and private safety in managing geologically hazardous areas and that are
consistent with the comprehensive plan goals and policies due to the inability of such
projects to meet strict variance decision criteria; and
WHEREAS, the City Council desires to allow appropriate project development
that can be permitted without impacting the public or private safety; now, therefore,
THE CITY COUNCIL OF THE CITY OF BAINBRIDGE ISLAND, WASHINGTON
DO ORDAIN AS FOLLOWS:
Section 1. Section 16.20.030(A)(49) of Chapter 16.20 of the Bainbridge Island
Municipal Code is amended to read as follows:
6. "Buffer" means an area adjoining to and a part of a critical area that
is required for the continued maintenance, functioning, and/or
structural stability of that critical area, or an area adjacent to a stream
or wetland that (a) surrounds and protects the functions and values of
the stream or wetland from adverse impacts, (b) is an integral part of a
stream or wetland ecosystem, and (c) provides shading, input of
organic debris and coarse sediments, room for variation in stream or
wetland edge, habitat for wildlife, and protection from .harmful
intrusion, to protect the public from losses suffered when the functions
and values of the wetland or stream are degraded.
33. "Landslide hazard areas" means areas which are potentially
subject to risk of mass movement due to a combination of factors,
including historic failures, geologic, topographic, and hydrologic
features. Some of these areas are identified in the Department of
Ecology Coastal Zone Atlas and USGS Surface Geology Map of
Bainbridge Island (Haugerud, 2001). The presence of these factors
shall be determined through assessment, by the least intrusive means,
by the Cit~Engineer or at the City Engineer's request by a third party
eg oengineer or geotechnical expert, prior to issuance of andpermit.
Landslide hazard areas include the following:
a. Areas characterized by slopes greater than 15 percent having
springs or groundwater seepage and having impermeable soils
(typically silt and clay) overlain or frequently interbedded with
permeable granular soils (predominantly sand and gravel);
b. Any area potentially unstable due to rapid stream incision or
stream bank erosion;
c. Any area located on an alluvial fan, debris flow deposit, or in a
debris flowpath, presently or potentially subject to impacts or
inundation by debris flows or deposition of stream-transported
sediments;
d. Any area with a slope of 40 percent or greater and with a
vertical relief of 10 or more feet except areas composed of
competent consolidated rock;
e. Any area designated or mapped as class U, UOS, or URS by the
Department of Ecology Coastal Zone Atlas and/or mapped as a
landslide or scarp on the USGS Surface Geology Map of
Bainbridge Island (Haugerud, 2001); or
f. -z4~~rea~~,:~et-e€-t#e-~efl~ o~ „ ~;ao~ „~ „ „~ .~,o
a13e~~e--la~~slia~ '~~ ~ra ~rea~, exEep~debr~~~-areas-t~-~tr~
yep e~s~ti~eH-areas~~; ~~~o ~-arE~~e~Ced-gip cciul
~UJIiJ Cil l
"49. "Variance" means relief from the provisions of the habitat buffer
standards for wetlands or fish and wildlife habitat conservation areas;
,where strict
application of this chapter renders compliance with these provisions an
unnecessary hardship by strict application of this Chapter, as provided
for in BIMC 16.20.070."
Section 2. Section 16.20.040(C) of Chapter 16.20 of the Bainbridge Island Municipal
Code is amended to read as follows:
"C. Exemptions. The following activities are exempt from the
requirements of this chapter:
2
1. Emergencies that threaten the public health, safety and welfare.
An "emergency" is an unanticipated and immediate threat to public
health, safety, or the environment which requires action within a time
too short to allow compliance with this chapter. Restoration or
mitigation of critical areas and buffers impacted by emergency action
shall be required in a timely matter.
2. Ongoing agricultural activities using best management practices as
included in a farm management plan developed by the Kitsap
Conservation District.
3. Normal and routine maintenance of structures, landscaping and
vegetation that will not further impact or alter critical areas or buffers.
4. Normal and routine maintenance and operation of pre-existing
retention/detention facilities, biofilters and other stormwater
management facilities, irrigation and drainage ditches, farm ponds,
fish ponds, manure lagoons, and livestock water ponds; provided, that
such activities shall not involve conversion of any wetland not
currently being used for such activity. Any maintenance of ponds
located in stream habitat areas shall require appropriate approval from
the Washington Department of Fish and Wildlife.
5. Structural alterations to buildings that do not increase the structural
footprint or introduce new adverse impacts to an adjacent critical areal
except for structures located on ~eolo~ically hazardous areas which
are not exempt.
6. Normal and routine maintenance or repair of existing utility
structures within a right-of--way or existing utility corridor or
easements, including the cutting, removal and/or mowing of
vegetation.
7. Forest practices conducted pursuant to Chapter 76.09 RCW, except
Class IV (general conversions) and Conversion Option Harvest Plans
(COHP).
8. Activities within a portion of a wetland buffer or fish and wildlife
habitat area buffer located landward of an existing, substantially
developed area, such as a paved area, or permanent structure, which
eliminates or greatly reduces the impact of the proposed activities on
the wetland or fish and wildlife habitat area. The Director shall review
the proposal to determine the likelihood of associated impacts.
9. Hazard Tree Removal. Where a threat to human life, property, or
slope stability is demonstrated, the Director may allow removal of
danger or hazard trees subject to the following criteria:
a. Tree removal is the minimum necessary to balance protection of
the critical area and its buffer with protection of life and property;
and
b. The critical area or its buffer shall be replanted as determined
by the Director.
The Director shall coordinate review with the Washington State
Department of Fish and Wildlife as determined necessary to assure
3
habitat protection. The Director may require the applicant to
consult with a professional forester or a certified arborist prior to
tree removal. Hazard tree abatement can sometimes be achieved by
felling the tree or trimming the tree. Habitat needs may require
leaving the fallen tree in the riparian corridor or maintaining a high
stump for wildlife habitat.
10. Aquifer recharge areas. A person, or property, shall be exempt
from the provisions of this chapter unless either of the following is
true:
a. The property is located in a fish and wildlife habitat
conservation area, frequently flooded area, geologically hazardous
area, and/or wetland; or
b. One of more of the uses identified in BIMC 16.20.120.B-E are
proposed."
Section 3. Section 16.20.040(D) of Chapter 16.20 of the Bainbridge Island Municipal
Code is amended to read as follows:
"D. Standards for existing development.
1. Existing structures and related improvements. Structures and
related improvements that were legally built or vested prior to the
effective date of Ordinance No. 2005-03 that do not meet the setback
or buffer requirements of this chapter may continue to exist in their
present form, and may be altered, including remodeled, reconstructed,
or expanded, if such alteration complies with the provisions of this
Section.
2. Existing structures, not located in a geolo ig cally hazardous area,
that were legally built or vested prior to the effective date of Ordinance
No. 2005-03 may be altered if:
a. There is no change in the footprint of the building;
b. The remodel is entirely inside the existing building;
c. There is no further encroachment into the buffers required
pursuant to this chapter unless a Variance is first approved; or
d. Any expansion of the building footprint is exclusively on the
sides that do not touch the buffers.
3. Existing property improvements other than structures,. including
driveways, parking areas, yards, play areas, storage areas, and similar
improvements that were legally established or vested prior to the
effective date of Ordinance No. 2005-03 may be altered i£
a. There is no change in the location of the improvement;
b. Any alteration of the improvement is entirely inside of the
existing boundaries of the improvement;
4
c. There is no further encroachment into the buffers unless a
Variance is first approved; or
d. Any increase in the area of the improvement is exclusively on
the sides that do not touch the buffers.
4. Alterations permitted by this Section shall not be exempt from
applicable City review or permit requirements or other applicable City
codes."
Section 4. Section 16.20.070(A) of Chapter 16.20 of the Bainbridge Island Municipal
Code is amended to read as follows:
"A. Applicability. Ari applicant may seek a variance from habitat buffer
standards for wetlands or fish and wildlife habitat conservation areas; --er
~° ° ^'~ ~~°a ^'^ ^~11=~''° a ~r°~ where application of the
"iuv u.i wvu,
standards renders compliance with these provisions an unnecessary
hardship. A variance is authorized primarily for relief from wetland and
stream habitat buffer standards that result in greater reduction than can be
achieved through the buffer averaging in Subsection 16.20.050(B) above.
A variance will not be allowed for reduction of the water quality buffers.
Alterations specific to wetlands and streams and their water quality buffers
are processed pursuant to a reasonable use exception, BIMC 16.20.080."
Section 5. Section 16.20.150(D) of Chapter 16.20 of the Bainbridge Island Municipal
Code is amended to read as follows:
"D. Minimum Submittal Requirements.
1. All geologically hazardous areas and buffers.
a. Indemnification. An indemnification or hold harmless agreement
shall be required for all projects in geologically hazardous areas and
buffers except erosion hazard areas and tsunami hazard areas. The
form of the agreement shall be approved by the City and executed
prior to the commencement of construction or site alteration.
b. Notice. T~~tli ''' ~ ~ ° ~°~' ~ ~' ^c°d
~ ~ * ~^^~*°a ~ ^ ~~„ari;,~° ~~~~ra ^ ~~ ~ A notice of intent to
re~.,,
construct on a landslide hazard area or reduce the minimum buffer in a
landslide hazard area shall be given pursuant to BIMC 2.16.085.C.2.
The notice of intent shall be issued within 14 days of a completed
application pursuant to BIMC 2.16.055. The notice shall include a 21-
day comment period and no permits or approval of reduced buffers
shall be issued before the end of the comment period.
c. All reports or analyses required or prepared pursuant to this Section
shall be prepared pursuant to BIMC 16.20.090, 16.20.150, and/or any
other applicable provisions of this chapter, and shall meet the
satisfaction of, and be approved by, the City Engineer prior to the
commencement of any development activity.
d. To protect public health, safety and welfare, the City Engineer may
call for a third party review of an~~eotechnical report in cases where
there may be potential for substantial damage to life, property or the
environment should the proposed engineering solution fail. When a
third party review is required, costs incurred for a qualified third party
geotechnical engineer to perform the review shall be borne by the
applicant.
a~~~r~ig~en~'~.Mme--~~gi-r}ee~-;may--Ret~~~i~~~t
mi~ig~t~e~fan-is--x~eEess~e-r~ti-gat~e~ per-s~~n~
~~ rte;+,, ~^o;^ee~pr6~o~--app~e~ri-~t
at'k E~-tt e, am6~get#e~eme~~ara~a~~vourcr~ `v'°c-g°cccrrron
manager~r~~e~~s~rc~i9~re€->3~ll~d~ad~ e~~~ ~'~' °~~
rrntr~ °
ere~s}6i3-6~1 6-fte-9~-6~f ~~t~~l~-cisi "cam-Grim-ietc'i~H~ir~ =ov'c^ai:rl~yvr=ri~vc
O°sc+rr'a"c+c'a'i-e-~t~~'~-1--be-i~6~'° •,~ 1<, „+°,.+°.a +1,~„ .:+L..,,,+ +l,° ° .,~ ~ ~L,
i~2~-€ti~•-1 +1~.~,~„1~i4'~1~--~jrt~3lr ~'~z
neEZSSa~-te~~e~ee~e-s~c~et~t-rye-Qt~enea~ ~ ~'~e~r
a~t~Le~~ +~ -rl,° ,n,:+;,,.,+;e~~rr~-1}e~°`ca-ny-e~aCri-ifie
pre€es~ionalr.~~~^'' ~e~trde~eeTee-~i~~~~exg~e
l~regeel~e,.;~~r~d,~el}er-yes--b~efeg~-Qependt~eri
sree-in~e~c~s~Ees--and---a~deemed-app~ep~te--~y~ ~';+
e. Geological Hazards Assessment. A Critical Area report is re uired
for all projects in geolo ically hazardous areas and buffers and shall
contain an assessment of geological hazards including the following
site- and proposal-related information at a minimum:
i. Site and Construction Plans. The report shall include a copy of the
site plans for the proposal showing_
A. The type and extent of geologic hazard areas, and other
Critical Areas, and buffers on, adiacent to, or within a zone or
distance of potential significant influence as determined b~
professional en ing eer/ geologist;
B. Proposed development, including the location of existing and
proposed structures, fill, storage of materials, and drainage
facilities, with dimensions indicating distances to the floodplain
if available;
C. The topography, as determined by a professional engineer or
geologist, of the project area and all hazard areas addressed in
the report; and
D. Clearin lg imits.
ii. Assessment of Geological Characteristics. The report shall
include an assessment of the geologic characteristics of the soils
sediments, and/or rock of the project area and potentially affected
adjacent properties, and a review of the site history re arding
landslides, erosion, and prior rg ading. Soils analysis shall be
accomplished in accordance with accepted classification systems in
use in the region. The assessment shall include, but not be limited
to:
A. A description of the surface and subsurface geology,
h d~gy, soils, and vegetation found in the project area and in
all hazard areas addressed in the report;
B. A detailed overview of the field investigations, published
- data, and references; data and conclusions from past assessments
of the site; and site specific measurements, test, investi atg ions,
or studies that support the identification of geolo ig rally
hazardous areas; and
C. A description of the vulnerability of the site to seismic and
other geologic events.
iii. Analysis of Proposal. The report shall contain a hazards anal
including a detailed description of the project, its relationship to the
geologic hazard(s), and its potential impact upon the hazard area,
the subject property, and affected adjacent properties.
iv. Minimum Buffer and Building Setback. The report shall make a
recommendation for the minimum no-disturbance buffer and
minimum building setback from any geologic hazard based upon the
geotechnical analysis. Where the recommended buffers are less than
the standard buffers set forth in section 16.20.150(E) of BIMC, the
rationale and basis for the reduced buffer shall be clearly articulated
and demonstrate that the protection standard set forth in that section
has been met.
£ Incorporation of Previous Study. Where a valid Critical Areas report
has been prepared for a specific site, and where the proposed land use
activity and surrounding site conditions are unchanged, said report may
be incorporated into the required Critical Area report, if deemed still
valid and appropriate b~professional engineer or geologist. The
applicant shall submit a hazards assessment detailing any changed
environmental conditions associated with the site based on best
professional judgment of the en ing eer/ geologist.
g. Mitigation of Long-Term Impacts. When hazard mitigation is
required the mitigation plan shall specifically address how the activity
maintains or reduces the pre-existing level of risk to the site and
adjacent properties on a long-term basis (equal to or exceeding the
projected life span of the activity or occupation). Proposed miti ag tion
techniques shall be considered to provide long-term hazard reduction
only if they do not require regular maintenance or other actions to
maintain their function. Mitigation may also be required to avoid any
increase in risk above the pre-existing conditions following
abandonment of the activity.
h. In addition to the general Critical Area report requirements of
section 16.20.150(D)(1)~, Critical Area reports for geologicallX
hazardous areas must meet requirements of this section. Critical Area
reports for two or more types of Critical Areas must meet the report
requirements for each relevant type of Critical Area.
zzr6~a~r-e&S~rii-efA~-kAi~cvircrv r isi'ca-v cr c°ciriea
.:1 0 ~1,~11 loo ~„1„Y,;++oa +., +i,o lam;+., ., r +., +l,o ; ~,f ~ ~lo.,r;,,,. ,.
., rl ; ;+
~2 Landslide Hazard and Erosion Hazard Areas. In addition to the basic Critical
Areas report requirement, a Critical Areas report for an erosion hazard or
landslide hazard area shall include the following information at a minimum:
a. Erosion Control. An erosion control plan prepared by a civil
engineer shall be submitted to the City prior to the issuance of a
clearing or grading permit.
b. The applicant shall provide a geotechnical analysis containing
the following information: spec~ed~tl~C~~rgi~~~~
Ee~c-k~le~~e-de~~elepmerlt--prepeeets t~e~ ~~f
sir
i. Site Plan. The Critical Area report shall include a copes
the site plan for the roposal showing_
A. The height of slope, slope gradient, and cross-section of
the project area;
B. The location of sprin s, seeps, or other surface
expressions of ground water on or a zone or distance of
potential significant influence as determined by a
professional en ineer/ geolo isg t; and
C. The location and description of surface water run-off
features.
ii. Hazards Analysis. The hazards analysis component of the
Critical Areas report shall specifically include:
A. A description of the extent and type of vegetative cover
B. A description of subsurface conditions based on data
from site-specific explorations;
C. Descriptions of surface and ground water conditions,
public and private sewage disposal systems, fills and
excavations, and all structural improvements;
D. An estimate of slope stability and the effect construction
and placement of structures will have on the slope over the
estimated life of the structure:
E.. An estimate of the bluff retreat rate that recognizes and
reflects potential catastrophic events such as seismic
activity or a one hundred-year storm event;
F. Consideration of the run-out hazard of landslide debris
and/or the impacts of landslide run-out on down sloe
properties;
G. A study of slope stability including an anal siy s of
proposed cuts, fills, and other site rg_ading=
H. Recommendations for buildin sg itin~ limitations; and
I. An analysis of proposed surface .and subsurface drainage,
and the vulnerability of the site to erosion.
iii. Geotechnical En ing eerin~port. The technical
information for a project within a landslide hazard area shall
include a geotechnical en ineering report prepared by a
licensed engineer that presents en ing_ Bering recommendations
for the following:
A. Parameters for design of site improvements including
a~~ropriate foundations and retaining structures. These
should include allowable load and resistance capacities for
bearing and lateral loads, installation considerations, and
estimates of settlement performance;
B. Recommendations for drainage and subdrainage
improvements;
C. Earthwork recommendations including clearing and site
preparation criteria, fill placement and compaction criteria,
temporary and permanent slope inclinations and protection,
and temporary excavation support, if necessary; and
D. Mitigation of adverse site conditions including slope
stabilization measures for seismically unstable soils,
surface water management, location and methods of
erosion control, a vegetation management and/or replanting
plan and/or other means for maintaining long-term soil
stability if appropriate,
43. Seismic Hazards Areas. In addition to the basic report requirements,
a Critical Area report for a seismic hazard area shall also meet the
following requirements:
a. Fault Hazard. The applicant shall provide ageologic/geotechnical
analysis containing information specified by the City Engineer that
documents the presence or absence of any surface deformation on the
site in areas mapped by the City. If deformation is located, the
applicant shall provide a geotechnical analysis containing information
specified by the City Engineer, which concludes that the development
proposal as mitigated meets the standards of this section.
b. Liquefaction Hazard. The applicant shall provide a geotechnical
analysis containing information specified by the City Engineer that
meets the standards of this section (as mitigated).
c. Seismic Landslide Hazard. The applicant shall provide the same
analysis and plan as required for landslide hazard areas, pursuant to
BIMC 16.20.150(D 1 h 1 .
9
~4. Tsunami Hazards. The City shall provide applicants for development
in low lying shoreline areas and other areas where flood elevation is
controlled by tide level with information on tsunami hazards.
65. Zone of Influence Areas beyond the established buffer. The applicant
shall have the surface and storm water mana eg_ment plan for the project
reviewed by a geotechnical engineer to determine if there is any
potentially adverse impacts to the landslide hazardous area. If the
geotechnical engineer or the City Engineer determines that there are
potential adverse impacts, the applicant shall provide a geotechnical
analysis containing information specified by the City Engineer which
analyzes the potential impacts to the geological hazard from the proposed
development in the zone of influence and meets the standards of this
section. The report shall contain recommendations to avoid adverse
impacts to the geologically hazardous area. Concentrated discharge of
stormwater shall only be allowed where specially recommended in the
report and authorized by the City Engineer."
Section 6. Section 16.20.150(E) of Chapter 16.20 of the Bainbridge Island Municipal
Code is amended to read as follows:
"E. Development Standards.
1. General Requirements. The City Engineer shall establish
administrative procedures to implement BIMC 16.20.150. These
procedures shall include review by an administrative Technical Review
Committee if the development is proposed in a landslide hazard area
and/or its buffer. The Technical Review Committee shall include a civil
engineer, a eolo isg t or geotechnical engineer and h d~gist. Where
landslide areas are associated with other critical areas it shall also include
an experienced biologist, ecologist or wetland specialist. The City
Engineer must document in the file those involved in the Technical
Review Committee and their expertise. ~'''° r:*~~ ~'r°~^°°r ^''^" ~'°*°~~~°
p~e~es~~e~-aEeept-able---lei=el, ^o~~a~-ail-actii~ties ~itl3in
gee~egi°°^'~ly--naiar-dents--areas. The applicant shall meet the following
standards for all activities permitted in geolo ig tally hazardous areas or
associated buffers:
a. The proposed activity shall not create a net increase in geological
instability, either on- or off-site, which is defined as follows:
i. The subject parcel shall not be less stable after the planned
development than before; and
ii. The adjacent parcels shall not have greater risk or be less stable
after the planned development than before.
b. The proposed activity shall not increase the risk of life safety due to
geological hazards above professionally acceptable levels.
c. The proposed activity shall not increase the risk due to geological
hazards above professionally acceptable levels for:
10
i. Property loss of any habitable structures or their necessary
supporting infrastructure on-site or;
ii. Risk to any off-site structures or property of any kind; and
d. Proposed buildings shall be constructed using appropriate
engineering methods that respond to the geologic characteristics
specific to the site in order to achieve the highest standard of safety
feasible.
e. The proposed development shall not decrease the factor of safety
for landslide occurrences below the limits of 1.5 for static conditions
and 1.2 for dynamic conditions. Analysis of dynamic conditions shall
be based on the minimum horizontal acceleration as established by the
current version of the. International Building Code.
£ The proposed activity shall not further degrade the values and
functions of the associated critical areas.
2. Development Design and Location.
• R~
~rt, • cn ~ ,.* ~, a oa +i • a ~ ~ ~n non riz~r~ ~n~L
[c
'~
Tm
~v-
Ca ~ aS-o'u' rr'iir°crcriTrz-~,o-.zLzo . o~ o~-r ~ccrrarr ~ ~
z~7v,~vc-ar°cE'c-iizcry~-ve~
cc~[c
'"+
°~~
'
i
.
p
~
p
G
p
~
~
cpcr
i-~fe~l'ffE~ti'8'Yi~~~
'~" """"~'}~
""'~ '~ t3Yl
engi3~ee~~s--sperm°a~o ~;+., ~„ „eo,.~ +~,.,+ ,ao,,-.,...,~+,..,+o~ +~,.,+ +~,o
.~
f~~~~,Qt~nEr,,~ o ~i„ o ~,,,i.;i;+. ,,,a +i,.,+ ,.+~,o ra~P~n,~
,.+ ~~+o..,,.,+;,,o o ~+~.
o
The followin~guirements shall apply to any land or ve etg ation
modification or construction within a landslide hazard area and/or its
buffer as described herein:
a. Buffer Requirement: A buffer equal to the height of the slope or
fift~50) feet whichever is greater, shall be established from all edges
of a landslide hazard area except where no other reasonable alternative
exists, reduction may be allowed as follows:
i. Buffer Reduction.
A. Buffer reductions may be allowed provided a critical
areas report pursuant to BIMC 16.20.150(D~(1)(2) and and
related section of BIMC 1.6.20, demonstrates to the Director that
the buffer reduction will not reduce the level of protection to the
proposed development adjacent properties, and other associated
critical areas as required by BIMC 16.20.150(E)(1).
B. For sloes fort~(40) percent or greater the buffer maw
no case be reduced to less than ten (10) feet. A decision by the
Director to reduce the buffer shall be based on a critical areas
report pursuant to BIMC 16.20.150(D~(1)(2) that includes athird-
part~pendent review by a qualified ~eotechnical en ig Weer
pursuant to BIMC 16.20.150(D)(1)(d);
ii. Increased Buffer. The buffer m~ be increased beyond that
specified in subsection (a) above if the Director determines a larger
buffer is necessary to prevent risk of damage to the proposed
11
development, adjacent developments, and uses and the associated
critical areas;
iii. Building Setback. All building and structures shall have a
minimum setback of (15) feet from the outer edge of the buffer
around landslide hazard areas to allow for construction activity;
and
iv. Vegetation Retention. Unless otherwise provided or as part of
an approved alteration, removal of vegetation from an erosion or
landslide hazard area or related buffer shall be prohibited.
b. All development proposals shall be designed to avoid impacts to
the geologically hazardous areas. The development shall be designed
to minimize the footprint of building in other disturbed areas,
minimize removal of vegetation, minimize topographic change, and
retain open space to the maximum extent practicable;
c. Development design shall utilize clustering, under-structure
parking, multi-level construction, and tiered foundations to the extent
feasible to minimize impervious lot coverage, slope disturbance, and
changes to the natural topography;
d. Access shall be in the least sensitive part of the site, and common
access drives and utility corridors are required to the extent feasible;
e. Roads, walkways and parking areas shall be designed to parallel the
natural contours to the extent feasible;
f. All proposed clearing and tree removal shall be marked in the field
for inspection and approval prior to alteration of the site;
g. Cut and fill slopes shall be prepared and maintained to control
against erosion and instability; a~
h. Drainage and stormwater designs in zones of influence shall
incorporate elements of low impact design, to the extent feasible, and
shall be designed in such a manner that stormwater outlet discharges
do not create additional impacts. The proposed activities shall not
increase surface water discharge or sedimentation to adjacent
properties beyyond the pre-development condition; and
j. Landslide hazard areas on slo ep s forty (40) percent or greater shall
only be altered as allowed by the exemptions listed in 16.20.150(F). A
landslide or erosion hazard area, located on a slope less than forty (40~
percent, matey be altered pursuant to the standards of BIMC
16.20.150(E (1).
Section 7. Section 16.20.150(F) of Chapter 16.20 of the Bainbridge Island Municipal
Code is amended to read as follows:
"F. Exemptions. The following activities are permitted in geologically
hazardous areas or associated buffers; provided, that the applicant can
demonstrate that applicable standards in Subsection (-C~ 16.20.150(E~(1~
can be met, or where the applicant has demonstrated through a Critical
12
Areas report prepared by a geotechnical engineer in accordance with the
specifications of the City Engineer that no adverse impact will result from
the proposal and where approved surface water drainage will. result in
minimum slope and vegetation disturbance:
1. Structural alteration to an existin lg e~ally constructed structure that
does not increase the structural footprint and .are determined b
City Engineer as having a minimal potential for increasing landslide
hazard;
2. Surface Water Management: Slopes or buffers may be used for
improved surface water conveyance if no other reasonable alternative
route is available. Installation techniques shall minimize disturbance
to the slope and vegetation.
~.3. The construction of approved public or private trails; provided,
they are constructed of material, for example cable lift access, which
will not contribute to surface water runoff;
~.4. The construction of public or private utility corridors or streets;
provided, it has been demonstrated that such alterations will not
increase landslide or erosion risks through required analysis pursuant
to 16.20.150(D)(1)(2) and the City determines that no other feasible
alternative exists;
~5 Select Vegetation Removal Activities. The following vegetation
removal activities are allowed, provided that no vegetation shall be
removed from a geolo ig cal1Y hazardous area or its buffer without.
approval from the Director;
a. Removal. of noxious weeds using .non-motorized equipment or
light equipment if approved by the Director. If herbicides are used
to control. these weeds a licensed applicator is required, unless
otherwise authorized by the Director. Bare .areas remaining after
weed removal shall be re-vegetated with native plant species
pursuant to an enhancement Klan approved by the City.
b. Removal and. ~runin~ of hazard trees as defined. by ISA
(International Society of Arboriculture) standards b~provided that
a ISA. certified arborist documents the hazard and provides a report
to the Director for review and approval. "hhe landowner shall
replace any cut tree with three replacement trees (3:1 replacement
ratio) six months prior to tree removal with trees a minimum of six
feet in height and 4 inches in diameter, in accordance with. an
approved replacement plan. The Director may require a second
opinion from a certified ISA arborist in cases of removal of hazard
trees. Replacement trees shall be native sKecies indigenous to the
vicini~ and approved by the Director. Size of trees shall be
approved by the Director. The landowner shall. ensure 100%
survival of replacement trees
4.6. The trimming and limbing of vegetation ~~~' *'~° r°~°~~~' °~+r°°~ for
the creation and maintenance of view corridors in accordance with the
pruning standards of the International Society of Arboriculture; provided,
13
that the soils are not disturbed and activity will not increase the risk of
landslide or erosion. T'~° *'~~„^~^^ ^~'~m'~° ^ ~a;<,;a„^' +r°°° ~ r°~ ^-°a
*^ r° ~~' ^~ *~°°~ ~ ~ - r:a^r~ All vegetation removal must be
based on a plan developed by a certified arborist and reviewed by a
geotechnical engineer to determine if it will impact slope stability.
7. Limited Exemption -For landslide areas 40% or greater with a vertical
elevation change of up to twenty (20 .feet may be exempted from
16.20.150(E)(2)(i) based on the City review and acceptance of a Critical
Areas report from a geologist or licensed geotechnical engineer in
accordance with 16.20.150(D) when no adverse impact will result from
the exemption.
Section 9. Severability. If any one or more section, subsections, or sentences of this
ordinance are held to be unconstitutional or invalid, such decision shall not affect the
validity of the remaining portion of this ordinance and the same shall remain in full force
and effect.
Section 10. Effective Date. This ordinance shall take effect on and be in force five (5)
days from and after its passage, approval, and publication as required by law.
PASSED by the City Council this 14~' day of November 2007.
APPROVED by the Mayor this 14`h day of November 2007.
Darlene Kordonowy, Mayor
ATTEST/AUTHENTICATE:
\lc~n4Q.rnQ~-. ~ch5~
Rosalind D. Lassoff, CM ,City Clerk
FILED WITH THE CITY CLERK:
PASSED BY THE CITY COUNCIL
PUBLISHED:
EFFECTIVE DATE:
ORDINANCE NUMBER:
March 6, 2007
November 14, 2007
November 21, 2007
November 26, 2007
2007-OS
14