995 Attach Division 3 Environment
UNIFIED DEVELOPMENT CODE
ENVIRONMENT
Table of Contents
CHAPTER 18.20 STATE ENVIRONMENTAL POLICY ACT ......................................................................................... 1
18.20.010I ................................................................................................................................................. 1
NTENT
18.20.020C ...................................................................................................................... 1
ATEGORICAL EXEMPTIONS
18.20.030E ....................................................................................................................... 1
NVIRONMENTAL POLICIES
18.20.040D..................................................................................................... 1
ESIGNATION OF RESPONSIBLE OFFICIAL
18.20.050CCPDR.............................. 1
ONSISTENCY WITH THE OMPREHENSIVE LAN AND ADOPTED EVELOPMENT EGULATIONS
18.20.060P......................................................................................................................................2
UBLIC NOTICE
18.20.070P .............................................................................................................. 2
UBLIC AND AGENCY COMMENTS
18.20.080S ........................................................................................................................ 3
UBSTANTIVE AUTHORITY
18.20.090P.............................................................................. 4
REPARATION OF ENVIRONMENTAL IMPACT STATEMENTS
18.20.100I ............................................................................................ 4
MPOSITION OF FEES IN LIEU OF IMPROVEMENT
18.20.110N ................................................................................................................................. 4
OTICE OF ACTION
CHAPTER 18.21 CRITICAL AREAS AND RESOURCE LANDS .................................................................................... 5
18.21.010I ................................................................................................................................................. 5
NTENT
18.21.020B ......................................................................................................................... 7
EST AVAILABLE SCIENCE
18.21.030A,, .............................................................................................. 9
PPLICABILITY EXEMPTIONAND EXCEPTIONS
18.21.040A ............................................................................................................................ 11
LLOWED ACTIVITIES
18.21.050G ........................................................................................ 15
ENERAL CRITICAL AREA PROTECTIVE MEASURES
18.21.060W ......................................................................................................................................... 16
ETLANDS
18.21.070C ........................................................................................................ 27
RITICAL AQUIFER RECHARGE AREAS
18.21.080F ................................................................................................................. 28
REQUENTLY FLOODED AREAS
18.21.090FDP................................................................................................................ 34
LOOD AMAGE ROTECTION
18.21.100G.......................................................................................................... 40
EOLOGICALLY HAZARDOUS AREAS
18.21.110F .................................................................................... 44
ISH AND WILDLIFE HABITAT CONSERVATION AREAS
C18.20–SEPA
HAPTER TATE NVIRONMENTAL OLICY CT
18.20.010Intent
The intent of this chapter is to implement the requirements of the State
Environmental Policy Act, Chapter 43.21C(RCW) and Chapter197-11
(WAC).
18.20.020Categorical exemptions
A.The exempt threshold for minor new construction in the City of Yelm
pursuant to Section 197-11-800 WAC shall be:
1.Projects proposing 24or fewer single family dwelling units.
2.Projects proposing 32or fewer multiple family dwelling units.
3.The construction of any office, school, commercial, recreational,
service or storage building 10,000square feet or smaller which
creates fewer than 25new peak PM trips to the transportation system
and with 90or fewer associated parking stalls;
4.Any landfill or excavation permit for 1,000cubic yards or less
throughout the lifetime of the permit.
18.20.030Environmental policies
The following documents are to be considered as environmental policies of
the City of Yelm:
A.The City of Yelm Comprehensive Planand Joint Plan with Thurston
County, together with appendices and plans referenced therein;
B.The Yelm Creek Flood Hazard Management Plan;
C.The Nisqually River Management Plan;
D.The Unified Development Regulations of the Cityof Yelm;
E.The Yelm Engineering Specifications and Standard Detailsof the Cityof
Yelm.
18.20.040Designation of responsible official
For those proposals for which the Cityis the lead agency, the responsible
official shall be the Community Development Director of the Cityof Yelm.
18.20.050Consistency with the Comprehensive Plan and adopted
Development Regulations
The principal guide in measuring environmental impacts shall be whether the
proposed project is consistent with:
A.The Comprehensive Planfor the Cityof Yelm;
Environment - Page 1
B.The Development Regulations designed to implement the Comprehensive
Plan.
18.20.060Public notice
A.Whenever the responsible official issues a determination of non-
significance pursuant to Section 197-11-340 (2) WAC, notice shall be
given as follows:
1.Sending the determination by US Mail or email to agencies with
jurisdiction and affected tribes.
2.If public notice is required for the underlying permit, the notice shall
state whether a determination has been issued and when comments
are due.
3.If no public notice is required for the underlying permit, the
determination of non-significance shall be published in a newspaper
of general circulation in the City.
B.Whenever the responsible official issues a determination of significance
pursuant to Section 197-11-360(3) WAC, notice shall be given as
follows:
1.Sending the determination, draft scope, and scoping procedures by
US Mail or email to agencies with jurisdiction, agencies with
environmental expertise, and affected tribes.
2.The determination, draft scope, and scoping procedures shall be
published in a newspaper of general circulation in the City.
C.Whenever the Cityissues a draft environmentalimpact statement
pursuant to Section 197-11-455 (5) WAC, a supplemental environmental
impact statement under Section 197-11-620 WAC, or a final
environmental impact statement, notice of the availability of those
documents shall be provided as follows:
1.Sending a notice of availability by US Mail or email to agencies with
jurisdiction, agencies with environmental expertise, affected tribes,
and all persons, organizations, or agencies which provided comments
to the Cityon the project.
2.Publishing a notice of availability in a newspaper of general circulation
in the City.
18.20.070Public and agency comments
A.The responsible official shall consider all comments received during the
comment period for a determination of non-significance and, based on
those comments, may withdraw or modify the determination.
Environment - Page 2
B.The decision maker on the underlying permit shall consider all comments
received during the comment period for the determination of non-
significance or that of the underlying permit and, based on those
comments, may attach mitigation measures to the underlying permit
pursuant to Section 18.20.080 YMC.
C.The responsible official shall consider all comments received during the
comment period on a determination of significance and its draft scope
and, based on those comments, may modify the final scope for the
environmental impact statement.
D.The responsible official shallconsider and respond to all comments
received during the comment period on a draft environmental impact
statement in thefinal environmental impact statement.
18.20.080Substantive authority
A.The decision maker on the underlying permit may approve the
underlying permit with mitigation measures pursuant to Section 197-11-
660 WAC through the use of substantive authority.
Mitigation measures attached to the underlying permit through the use of
substantive authority must be:
1.Based on the goals and policies of the Yelm Comprehensive Plan and
Development Regulations in effect at the time the threshold
determination is issued;
2.Related to specific, adverse environmental impacts clearly identified
in an environmental document onthe proposal;
3.Stated in writing by the decision maker, along with citation to the
policy that is the basis of the mitigation measure;
4.Reasonable and capable of being accomplished; and
5.Imposed on applicant only to the extent attributable to the identified
adverse impacts of its proposal.
B.The decision maker on the underlying permit may deny the permit for a
proposal pursuant to Section 197-11-660 WAC through the use of
substantive authority, provided that:
1.A finding is made that approving theproposal would result in
probable and significant adverse environmental impact identified in a
final or supplemental environmental impact statement; and
2.A finding is made that there are no reasonable mitigation measures
capable of being accomplished that are sufficient to mitigate the
identified impacts; and
3.The denial is based on one or more of the policies identified in this
Environment - Page 3
section and identified in writing in the decision document.
C.The Citydesignates and adopts by reference the following policies as the
basis for the exercise of authority pursuant to this section:
1The goals and policies of the Yelm Comprehensive Plan.
2.Adopted Capital Facilities Plans, including but not limited to the Water
System Plan, General Sewer Plan, Transportation Plan, and Parks
Plan.
3.The Yelm Unified Development Code, Title 18 YMC.
18.20.090Preparation of environmental impact statements
The preparation of draft and final environmental impact statements and
draft and final supplemental environmental impact statements shall be
accomplished under the direction of the responsible official.
18.20.100Imposition of fees in lieu of improvement
Where the public interest is served in the construction of a regional public
facility, and where a project impacts a public facility and will in fact be
benefitted by the facility, the Citymay impose a fee in lieu of requiring
construction of a portion of the public facility where:
A.A proportionality exists between the fee imposed, the facility to be
constructed, the impact of the project, and the benefit to the project;
B.The facility is identified in the Comprehensive Planand in specific public
facility plans designed to implement the Comprehensive Plan;
C.The Cityhas otherwise satisfied all requirements for the imposition of a
fee for development set forth in Chapter 82.02 RCW.
18.20.110Notice of action
The City,an applicant for,or a proponent of an action may publish a notice
of action pursuant to Section 43.21C.080 RCW for any action. The form of
such notice shall be substantially in the form provided in Section197-11-990
WAC and shall be published by the Cityclerk/treasurer, the applicant or the
proponent pursuant to Section 43.21C.080RCW.
Environment - Page 4
C18.21–CARL
HAPTER RITICAL REAS AND ESOURCE ANDS
18.21.010Intent
The intentof this chapter is to designate and classify ecologically sensitive
and hazardous areas and to protect these areas and their functions and
values, while also allowing for reasonable use of private property.
A.By limiting development and alteration of critical areas, this chapter
seeks to:
1.Protect members of the public and public resources and facilities from
injury, loss of life, or property damage due to landslides and steep
slope failures, erosion, seismic events, volcanic eruptions, or
flooding;
2.Maintain healthy, functioning ecosystems through the protection of
unique, fragile, and valuable elements of the environment, including
ground and surface waters, wetlands, and fish and wildlife and their
habitats, and to conserve the biodiversity of plant and animal
species;
3.Direct activities not dependent on critical areas resources to less
ecologically sensitive sites and mitigate unavoidable impacts to
critical areas by regulating alterations in and adjacent to critical
areas; and
4.Prevent cumulative adverse environmental impacts to water quality,
wetlands, and fish and wildlife habitat, and the overall net loss of
wetlands, frequently flooded areas, and habitat conservation areas.
Unavoidable impacts are impacts that remain after all appropriate
and practicable measures have been achieved.
B.The regulations of this chapter are intended to protect critical areas in
accordance with the Growth Management Act and through the application
of the best available science, and in consultation with state and federal
agencies and other qualified professionals, as determined according to
Sections 365-195-900 through 365-195-925WAC.
C.This chapter is to be administered with flexibility and attention to site-
specific characteristics. It is not the intent of this chapter to make a
parcel of property unusable by denying its owner reasonable economic
use of the property,or to prevent the provision of public facilities and
services necessary to support existing and planned development without
decreasing current service levels below minimum standards.
D.Relationship to other regulations.
1.These critical areas regulations shall apply as an overlay and in
addition to zoning and other development regulations adopted by the
Environment - Page 5
City.
2.When a property or development is subject to more than one critical
area overlay or other regulations apply to a development, the more
restrictive shall apply.
E.Compliance with the provisions of this chapter does not constitute
compliance with other federal, state, and local regulations and permit
requirements. The applicant is responsible for complying with these
requirements, apart from the process established in this chapter.
F.Interpretation. In theinterpretation and application of this chapter, the
provisions of this chapter shall be considered to be the minimum
requirements necessary, shall be liberally construed to serve the purpose
of this chapter, and shall be deemed to neither limit nor repealany other
provisions under state statute.
G.Jurisdiction –critical areas.
1.The Cityshall regulate all uses, activities, and developments within,
adjacent to, or likely to affect one or more critical areas, consistent
with the best available science and the provisions herein.
2.Critical areas regulated by this chapter include:
a.Wetlands;
b.Critical aquifer recharge areas;
c.Frequently flooded areas;
d.Geologically hazardous areas; and
e.Fish and wildlife habitat conservation areas.
3.All areas within the Citymeeting the definition of one or more critical
areas, regardless of any formal identification, are hereby designated
critical areas and are subject to the provisions of this chapter.
4.Areas adjacent to critical areas subject to regulation. Areas adjacent
to critical areas shall be considered to be within the jurisdiction of
these requirements and regulations. Adjacent shall mean any activity
located:
a.On a site immediately adjoining a critical area;
b.A distance equal to or less than the required critical area buffer
width and building setback;
c.A distance equal to or less than one-half mile (2,640feet) from a
bald eagle nest;
d.A distance equal to or less than 300feet upland from a stream,
wetland, or water body;
Environment - Page 6
e.Within the floodway, floodplain, or channel migration zone; or
f.A distance equal to or less than 200feet from a critical aquifer
recharge area.
H.Protection of critical areas. Any action taken pursuant to this chapter
shall result in equivalent or greater functionsand values of the critical
areas associated with the proposed action, as determined by the best
available science. All actions and developments shall be designed and
constructed to avoid, minimize, and restore all adverse impacts.
Applicants must first demonstrate an inability to avoid or reduce impacts,
before restoration and compensation of impacts will be allowed. No
activity or use shall be allowed that results in a net loss of the functions
or values of critical areas
I.Protect functions and values ofcritical areas with special consideration to
anadromous fish. Critical area reports and decisions to alter critical areas
shall rely on the best available science to protect the functions and
values of critical areas and must give special consideration to
conservation or protection measures necessary to preserve or enhance
anadromous fish, such as salmon and bull trout, and their habitat.
18.21.020Best available science
A.Best available science to be consistent with criteria. The best available
science is that scientific information applicable to the critical area
prepared by local, state, or federal natural resource agencies, a qualified
scientific professional, or team of qualified scientific professionals that is
consistent with criteria established in Sections 365-195-900 through
365-195-925WAC.Sources of the best available science are included in
Citations of Recommended Sources of Best Available Science for
Designating and Protecting Critical Areas, published by the Washington
State Department of Community, Trade and Economic Development.
B.Characteristics of a valid scientific process. In the context of critical areas
protection, a valid scientific process is one that produces reliable
information useful in understanding the consequences of a local
government's regulatory decisions, and in developing critical areas
policies and development regulations that will be effective in protecting
the functions and values of critical areas. To determine whether
information received during the permit review process is reliable
scientific information, the administrator shall determine whether the
source of the information displays the characteristics of a valid scientific
process. Such characteristics are as follows:
1.Peerreview. The information has been critically reviewed by other
persons who are qualified scientific experts in that scientific discipline.
The proponents of the information have addressed the criticism of the
Environment - Page 7
peer reviewers. Publication in a refereed scientific journal usually
indicates that the information has been appropriately peer-reviewed;
2.Methods. The methods used to obtain the information are clearly
stated and reproducible. The methods are standardized in the
pertinent scientific discipline or, if not, the methods have been
appropriately peer-reviewed to ensure their reliability and validity;
3.Logical conclusions and reasonable inferences. The conclusions
presented are based on reasonable assumptions supported by other
studies and consistent with the general theory underlying the
assumptions. The conclusions are logically and reasonably derived
from the assumptions and supported by the data presented. Any
gaps in information and inconsistencies with other pertinent scientific
information are adequately explained;
4.Quantitative analysis. The data hasbeen analyzed using appropriate
statistical or quantitative methods;
5.Context. The information is placed in proper context. The
assumptions, analytical techniques, data, and conclusions are
appropriately framed with respect to the prevailing body of pertinent
scientific knowledge; and
6.References. The assumptions, analytical techniques, and conclusions
are well referenced with citations to relevant, credible literature and
other pertinent existing information.
C.Nonscientific information. Nonscientific information may supplement
scientific information, but it is not an adequate substitute for valid and
available scientific information. Common sources of nonscientific
information include anecdotalinformation,no expertopinion,and
hearsay.
D.Absence of valid scientific information. Where there is an absence of valid
scientific informationor incomplete scientific information relating to a
critical area leading to uncertainty about the risk to critical area function
of permitting an alteration of or impact to the critical area, the
administrator shall:
1.Take a “precautionary or a no-risk approach” that strictly limits
development and land use activities until the uncertainty is
sufficiently resolved; and
2.Require application of an effective adaptive management program
that relies on scientific methods to evaluate how well regulatory and
nonregulatory actions protect the critical area. An adaptive
management program is a formal and deliberate scientific approach
to taking action and obtaining information in the face of uncertainty.
Environment - Page 8
An adaptive management program shall:
a.Address funding for the research component of the adaptive
management program;
b.Change course based on the results and interpretation of new
information that resolves uncertainties; and
c.Commit to the appropriate timeframe and scale necessary to
reliably evaluate regulatory and nonregulatory actions affecting
protection of critical areas and anadromous fisheries.
18.21.030Applicability, exemption, and exceptions
A.Applicability.
1.The provisions of this chapter shall apply to all lands, all land uses
and development activity, and all structures and facilities in the City,
whether or not a permit or authorization is required, and shall apply
to every person, firm, partnership, corporation, group, governmental
agency, or other entity that owns, leases, or administers land within
the City. No person, company, agency, or applicant shall alter a
critical area or buffer except as consistent with the purposes and
requirements of this chapter.
2.The Cityshall not approve any permit or otherwise issue any
authorization to alter the condition of any land, water, or vegetation,
orto construct or alter any structure or improvement in, over, or on
a critical area or associated buffer, without first ensuring compliance
with the requirements of this chapter.
B.Exempt activities. The following developments, activities, and associated
uses shall be exempt from the provisions of this chapter; providedthat
they are otherwise consistent with the provisions of other local, state,
and federal laws and requirements:
1.Emergencies. Those activities necessary to prevent an immediate
threat to public health, safety, or welfare, or that pose an immediate
risk of damage to private property and that require remedial or
preventative action in a timeframe too short to allow for compliance
with the requirements of this chapter.
Emergency actions thatcreate an impact to a critical area or its
buffer shall use reasonable methods to address the emergency; in
addition, they must have the least possible impact to the critical area
or its buffer. The person or agency undertaking such action shall
notify theCitywithin one working day following commencement of
the emergency activity. Within 30days,or sooner if the administrator
deems it is necessary to critical areasprotection, the administrator
shall determine if the action taken was within the scope ofthe
Environment - Page 9
emergency actions allowed in this subsection.
After the emergency, the person or agency undertaking the action
shall fully fund and conduct necessary restoration and/or mitigation
for any impacts to the critical area and buffers resulting from the
emergency action in accordance with an approved critical area report
and mitigation plan. The person or agency undertaking the action
shall apply for review, and the alteration, critical area report, and
mitigation plan shall be reviewed by the Cityin accordance with the
review procedures contained herein. Restoration and/or mitigation
activities must be initiated within one year, or sooner if the
administrator deems it is necessary to critical areas protection,of the
date of the emergency, and completedina timely manner;
2.Operation, maintenance, or repair. Operation, maintenance, or repair
of existing structures, infrastructure improvements, utilities, public or
private roads, dikes, levees, or drainage systems, that do not require
construction permits,if the activity does not further alter or increase
the impact to, or encroach further within, the critical area or buffer
and there is no increased risk to life or property as a result of the
proposed operation, maintenance, or repair.Restoration measures
taken to restore an altered or damaged natural feature include:
a.active steps to restore damaged wetlands, streams, protected
habitat, or their buffers to the functioning condition that existed
prior to an unauthorized alteration,and
b.actions performed to reestablish structural and functional
characteristics of the critical area that have been lost by alteration,
past management activities, or catastrophicevents.
3.Passive outdoor activities. Recreation, education, and scientific
research activities that do not degrade the critical area.
C.Exempt activities and impacts to critical areas. All exempt activities shall
use reasonable methods to avoid potential impacts to critical areas. Any
incidental damage to, or alteration of, a critical area that is not a
necessary outcome of the exempted activity shall be restored,
rehabilitated, or replaced.
D.Exception –essential public facilitiesor reasonable use.If the
application of this chapter would prohibit a development proposal for an
essential public facility, the agency or utility may apply for an exception.
If the application of this chapter would deny all reasonable economic use
of the subject property, the Cityshall determine if compensation is an
appropriate action, or the property ownermay apply for an exception.
Environment - Page 10
An exception to this chapter may be granted by the Hearing Examinerin
accordance withChapter 18.14 YMC.
18.21.040Allowed activities
A.Critical area report. Activities allowed under this chapter shall have been
reviewed and permitted or approved by the City, but do not require
submittal of a separate critical area report, unless required previously for
an underlying permit. The administrator may apply conditions to the
underlying permit or approval to ensure that the allowed activity is
consistent with the provisions of this chapter to protect critical areas.
B.Required use of best management practices(BMP’s). All allowed
activities shall be conducted using the best management practices that
result in the least amount of impact to the critical areas. BMP’s are
measures that control soil loss and reduce water quality degradation,
minimize adverse impacts to surface and ground water, protect trees and
vegetation, and provide standards for proper use of chemical herbicides.
TheCityshall observe the use of best management practices to ensure
that the activity does not result in degradation to the critical area. Any
incidental damage to, or alteration of, a critical area shall be restored,
rehabilitated, or replaced.
C.Allowedactivities. The following activities are allowed:
1.Permit Requests subsequent to previous critical area review.
Development permits and approvals that involve both discretionary
land use approvals and construction approvals if all of the following
conditions have been met:
a.The provisions of this chapter have been previously addressed as
part of another approval;
b.There have been no material changes in the potential impact to the
critical area or buffer since the prior review;
c.There is no new information available that is applicable to any
critical area review of the site or particular critical area;
d.The permit or approval has not expired or, if no expiration date, no
more than five years have elapsed since the issuance of that
permit or approval; and
e.Compliance with any standards or conditions placed upon the prior
permit or approval has been achieved or secured;
2.Modification to existing structures. Structural modification of, addition
to, or replacement of an existing legally constructed structure that
does not further alter or increase the impact to the critical area or
buffer and there is no increased risk to life or property as a result of
Environment - Page 11
the proposed modification or replacement; provided, that restoration
of structures substantially damaged by fire, flood, or act of nature
must be initiated within 18months of the date of such damage, as
evidenced by the issuance of a valid building permit, and diligently
pursued to completion;
3.Activities within the improved right-of-way. Replacement,
modification, installation, or construction of utility facilities, lines,
pipes, mains, equipment, or appurtenances, not including
substations, when such facilities are located within the improved
portion of the public right-of-way or a City-authorized private
roadway except those activities that alter a wetland or watercourse,
such as culverts or bridges, or result in the transport of sediment or
increased stormwater, subject to the following:
a.Critical area and/or buffer widths shall be increased, where
possible, equal to the width of the right-of-way improvement,
including disturbed areas; and
b.Retention and replanting of native vegetation shall occur wherever
possible along the right-of-way improvement and resulting
disturbance. Native vegetation includes plant species that are
indigenous to the area in question.
c.Removal of invasive species.
4.Minor utility projects. Utility projects which have minor or short-
duration impacts to critical areas, as determined by the administrator
in accordance with the criteria below, and which do not significantly
impact the function or values of a critical area(s); provided, that such
projects are constructed with best management practices and
additional restoration measures are provided. Minor activities shall
not result in the transport of sediment or increased stormwater. Such
allowed minor utility projects shall meet the following criteria:
a.There is no practical alternative to the proposed activity with less
impact on critical areas;
b.The activity involves the placement of a utility pole, street signs,
anchor, or vault or other small component of a utility facility; and
c.The activity involves disturbance of an area less than 75square
feet;
5.Public and private pedestrian trails. Public and private pedestrian
trails, except in wetlands, fish and wildlife habitat conservation areas,
or their buffers, subject to the following:
a.The trail surface shall meet all other requirements including water
quality standards set forth in the [locally adopted stormwater
Environment - Page 12
management regulations];
b.Critical area and/or buffer widths shall be increased, where
possible, equal to the width of the trail corridor, including disturbed
areas; and
c.Trails proposed to be located in landslide or erosion hazard areas
shall be constructed in a manner that does not increase the risk of
landslide or erosion and in accordance with an approved
geotechnical report;
6.Select vegetation removal activities. The following vegetation removal
activities; provided, that no vegetation shall be removed from a
critical area or its buffer without approval from the administrator:
a.The removal of the following vegetation with hand labor,light
equipmentor regulated grazing:
i.Invasive and noxious weeds;
ii.English ivy (Hedera helix);
iii.Himalayan blackberry (Rubus discolor, R. procerus);
iv.Evergreen blackberry (Rubus laciniatus);and
v.Scotch broom (Cytisus scoparius)
b.The removal of trees from critical areas and buffers that are
hazardous, posing a threat to public safety or posing an imminent
risk of damage to private property; provided, that:
i.The applicant submits a report from a certified arborist,
registered landscape architect, or professional forester that
documents the hazard and provides a replanting schedule for
the replacement trees;
ii.Tree cutting shall be limited to pruning and crown thinning,
unless otherwise justified by a qualified professional. Where
pruning or crown thinning is not sufficient to address the
hazard, trees should be removed or converted to wildlife snags;
iii.All vegetation cut (tree stems, branches, etc.) shall be left
within the critical area or buffer unless removal is warranted
due to the potential for disease or pest transmittal to other
healthy vegetation;
iv.The landowner shall replace any trees that are removed with
new trees at a ratio of two replacement trees for each tree
removed (2:1) within one year in accordance with an approved
restoration plan. Replacement trees may be planted ata
differentnearby location if it can be determined that planting in
Environment - Page 13
the same location would create a new hazard or potentially
damage the critical area. Replacement trees shall be species
that are native and indigenous to the site and a minimum of one
inch in diameter-at-breast height (dbh) for deciduous trees and
a minimum of six feet in height for evergreen trees as
measured from the top of the root ball;
v.If a tree to be removed provides critical habitat, such as an
eagle perch, a qualified wildlife biologist shall be consulted to
determine timing and methods or removal that will minimize
impacts; and
vi.Hazard trees determined to pose an imminent threat or danger
to public health or safety, to public or private property, or of
serious environmental degradation may be removed or pruned
by the landowner prior to receiving written approval from the
City; provided, that within 14days following such action, the
landowner shall submit a restoration plan that demonstrates
compliance with the provisions of this chapter.
c.Measures to control a fire or halt the spread of disease or
damaging insects consistent with the state Forest Practices Act;
Chapter 76.09 RCW; provided, that the removed vegetation shall
be replaced in-kind or with similar native species within one year in
accordance with an approved restoration plan; and
d.Unless otherwise provided, or as a necessary part of an approved
alteration, removal of any vegetation or woody debris from a
habitat conservation area or wetland shall be prohibited;
7.Chemical applications. The application of herbicides, pesticides,
organic or mineral-derived fertilizers, or other hazardous substances,
if necessary, as approved by the City; provided, that their use shall
berestricted in accordance with State Department of Fish and Wildlife
Management recommendations and the regulations of the State
Department of Agriculture and the U.S. Environmental Protection
Agency;
8.Minor site investigative work. Work necessary for land use submittals,
such as surveys, soil logs, percolation tests, and other related
activities, where such activities do not require construction of new
roads or significantamounts of excavation. In every case, impacts to
the critical area shall be minimized and disturbed areas shall be
immediately restored; and
9.Navigational aids and boundary markers. Construction or modification
of navigational aids and boundary markers.
Environment - Page 14
18.21.050General critical area protective measures
A.Critical area markers and signs.
1.The boundary at the outer edge of critical area tracts and easements
shall be delineated with permanent survey stakes as established by
local survey standards.
2.The boundary at the outer edge of the critical area or buffer shall be
identified with temporary signs prior to any site alteration. Such
temporary signs shall be replaced with permanent signs prior to
occupancy or use of the site.
3.These provisions maybe modified by the administrator as necessary
to ensure protection of sensitive features or wildlife needs.
B.Financial guarantee to ensure mitigation, maintenance, and monitoring.
1.When mitigation required pursuant to a development proposal is not
completed prior to the Cityfinal permit approval, such as final plat
approval or final building inspection, the Cityshall require the
applicant to post a financial guarantee in a form and amount deemed
acceptable by the City. If the development proposal is subject to
mitigation, the applicant shall post a financial guarantee security in a
form and amount deemed acceptable by the Cityto ensure mitigation
is fully functional.
2.The bond shall be in the amount of 150percent of the estimated cost
of the uncompleted actions or the estimated cost of restoring the
functions and values of the critical area that are at risk, whichever is
greater.
3.The bond shall be in the form of an assignment of savings account in
the Citytrust fund.
4.Financial guarantees shall remain in effect until the Citydetermines in
writing, that the standards bonded for have been met. Bonds or other
security shall be held by the Cityfor a minimum of five years to
ensure that the required mitigation has been fully implemented and
demonstrated to function, and may be held for longer periods when
necessary.
5.Depletion, failure, or collection of bond funds shall not discharge the
obligation of an applicant or violator to complete required mitigation,
maintenance, monitoring, or restoration.
6.Public development proposals shall be relieved from having to comply
with the bonding requirements of this section if public funds have
previously been committed for mitigation, maintenance, monitoring,
or restoration.
Environment - Page 15
7.Any failure to satisfy critical area requirements established by law or
condition including, but not limited to, the failure to provide a
monitoring report within 30days after it is due or comply with other
provisions of an approved mitigation plan shall constitute a default,
and the Citymay demand payment of any financial guarantees or
require other action authorized by the Citycode or any other law.
8.Any funds recovered pursuant to this section shall be used to
complete the required mitigation.
C.Critical area Inspections. Reasonable access to the site shall be provided
to the City, state, and federal agency review staff for the purpose of
inspections during any proposal review, restoration, emergency action,
or monitoring period.
18.21.060Wetlands
A.Designating wetlands. Wetlands are those areas, designated in
accordance with the Washington State Wetland Identification and
Delineation Manual (1997), that are inundated or saturated by surface or
ground water at a frequency and duration sufficient to support, and that
under normal circumstances do support, a prevalence of vegetation
adapted for life in saturated soil conditions. All areas within the City
meeting the wetland designation criteria in the Identification and
Delineation Manual, regardless of any formal identification, are hereby
designated critical areas and are subject to the provisions of this chapter.
B.Wetland ratings. Wetlands shall be rated according to the Washington
State Department of Ecology (Ecology) wetland rating system found in
the Washington State Wetland Rating System documents or as revised
by Ecology.
1.Wetland rating categories.
a.Category I. Category I wetlands are those that:
i.Represent a unique or rare wetland type; or
ii.Are more sensitive to disturbance than most wetlands; or
iii.Are relatively undisturbed and contain ecological attributes that
are impossible to replace within a human lifetime; or
iv.Provide a high level of functions. These include estuarine
wetlands, natural heritage wetlands, bogs, mature and old-
growth forested wetlands, wetlands in coastal lagoons and
wetlands that score more than 70 points in the 2004 rating
system.
b.Category II. Category II wetlands are difficult, though not
impossible, to replace, and provide high levels of some functions.
Environment - Page 16
Category IIwetlands in western Washington include wetlands
scoring between 51 and 69 points in the 2004 rating system.
c.Category III. Category III wetlands are those with a moderate
level of functions (scores between 30 and 50 points). Wetlands
scoring between 30 and 50 points generally have been disturbed in
some ways and are often less diverse or more isolated from other
natural resources in the landscape than Category II wetlands.
d.Category IV. Category IV wetlands have the lowest levels of
functions (scores less than 30 points) and are often heavily
disturbed.
2.Date of wetland rating. Wetland rating categories shall be applied as
the wetland exists on the date of adoption of the rating system by the
local government, as the wetland naturally changes thereafter, or as
the wetland changes in accordance with permitted activities. Wetland
rating categories shall not change due to illegal modifications.
C.Mapping. The approximate location and extent of wetlands are shown on
the critical area maps prepared by the Community Development
Department. These maps are to be used as a guide for the City, project
applicants, and/or property owners, and may be continuously updated as
new critical areas are identified. They are a reference and do not provide
a final critical area designation.
The exact location of a wetland's boundary shall be determined through
the performance of a field investigation by a qualified professional
wetland scientist applying the Washington State Wetlands Identification
and Delineation Manual as required by Section36.70A.175RCW.
D.Activities allowed in wetlands. The activities listed below are allowed in
wetlands in addition to those activities listed in, and consistent with, the
provisions established in allowed activities, and do not require
submission of a critical area report, except where such activities result in
a loss to the functions and values of a wetland or wetland buffer. These
activities include:
1.Conservation or preservation of soil, water, vegetation, fish, shellfish,
and otherwildlife that does not entail changing the structure or
functions of the existing wetland.
2.The harvesting of wild crops in a manner that is not injurious to
natural reproduction of such crops and provided the harvesting does
not require tilling of soil, planting of crops, chemical applications, or
alteration of the wetland by changing existing topography, water
conditions, or water sources.
3.Drilling for utilities under a wetland; providedthat the drilling does
Environment - Page 17
not interrupt the ground water connection to the wetland or
percolation of surface water down through the soil column. Specific
studies by a hydrologist are necessary to determine whether the
ground water connection to the wetland or percolation of surface
water down through the soil column is disturbed.
4.Enhancement of a wetland through the removal of nonnative invasive
species. Weeding shall be restricted to hand removal and weed
material shall be removed from the site. Bare areas that remain after
weed removal shall be re-vegetated with native shrubs and trees at
natural densities. Some hand seeding may also be done over the bare
areas with native herbs.
E.Wetland analysis.
1.A written assessment and accompanying maps of the wetlands and
buffers within 300feet of the project area, including the following
information at a minimum:
a.Wetland delineation and required buffers;
b.Existing wetland acreage;
c.Wetland category;
d.Vegetative, faunal, and hydrologic characteristics;
e.Soil and substrate conditions;
f.Topographic elevations, attwo-foot contours; and
g.A discussion of the water sources supplying the wetland and
documentation of hydrologic regime (locations of inlet and outlet
features, water depths throughout the wetland, evidence of
recharge or discharge, evidence of water depths throughout the
year: drift lines, algal layers, moss lines, and sediment deposits).
2.A discussion of measures, including avoidance, minimization, and
mitigation, proposed to preserve existing wetlands and restore any
wetlands that were degraded priorto the current proposed land use
activity.
3.A habitat and native vegetation conservation strategy that addresses
methods to protect and enhance on-site habitat and wetland
functions.
4.Functional evaluation for the wetland and adjacent buffer using a
local or state agency staff-recognized method and including the
reference of the method and all data sheets.
5.Proposed mitigation, if needed, including a written assessment and
accompanying maps of the mitigation area, including the following
Environment - Page 18
information at a minimum:
a.Existing and proposed wetland acreage;
b.Vegetative and faunal conditions;
c.Surface and subsurface hydrologic conditions including an analysis
of existing and future hydrologic regime and proposed hydrologic
regime for enhanced, created, or restored mitigation areas;
d.Relationships within watershed and to existing water bodies;
e.Soil and substrate conditions, topographic elevations;
f.Existing and proposed adjacent site conditions;
g.Required wetland buffers (including any buffer reduction and
mitigation proposed to increase the plant densities, remove weedy
vegetation, and replant the buffers);
h.Property ownership; and
i.Associated wetlands and related wetlands that may be greater than
300feet from the subject project.
6.Ascale map of the development proposal site and adjacent area. A
discussion of ongoing management practices that will protect
wetlands after the project site has been developed; including
proposed monitoring and maintenance programs.
7.A bond estimate for the installation (including site preparation, plant
materials and installation, fertilizers, mulch, stakes) and the proposed
monitoring and maintenance work for the required number of years.
8.Title Notification. All activity in critical area protection areas shall be
accompanied by a chapter.
F.Wetland performance standards –general requirements.
1.Activities may only be permitted in a wetland or wetland buffer if the
applicant can show that the proposed activity will not degrade the
functions and functional performance of the wetland and other critical
areas.
2.Activities and uses shall be prohibited in wetlands and wetland
buffers, except as provided for in this chapter.
3.Category I wetlands. Activities and uses shall be prohibited from
Category I wetlands, except as provided for in the public agency and
utility exception, reasonable use exception, and variance sections of
this chapter.
4.Category II and III wetlands.
a.Water-dependent activities may be allowed where there are no
Environment - Page 19
practicable alternatives that would have a less adverse impact on
the wetland, its buffers and other critical areas.
b.Where non-water-dependent activities are proposed, it shall be
presumed that alternative locations are available, and activities
and uses shall be prohibited, unless the applicant demonstrates
that:
i.The basic project purpose cannot reasonably be accomplished
and successfully avoid, or result in less adverse impact on, a
wetland on another site or sites in the general region; and
ii.All alternative designs of the project as proposed, that would
avoid or result in less of an adverse impact on a wetland or its
buffer, such as a reduction in the size, scope, configuration, or
density of the project, are not feasible.
5.Category IV wetlands. Activities and uses that result in unavoidable
and necessary impacts may be permitted in Category IV wetlands
and associated buffers in accordance with an approved critical area
report and mitigation plan, and only if the proposed activity is the
only reasonable alternative that will accomplish the applicant's
objectives. Full compensation for the acreage and loss functions will
be provided.
6.Wetland buffers.
a.Standard buffer widths. The standard buffer widths presume the
existence of a relatively intact native vegetation community in the
buffer zone adequate to protect the wetland functions and values
at the time of the proposed activity. If the vegetation is
inadequate, then the buffer width shall be increased or the buffer
should be planted to maintain the standard width. Required
standard wetland buffers, based on wetland category and land use
intensity, are as follows:
i.Category I:
Natural Heritage Wetlands250 feet
Bogs250 feet
High level of function for habitat (score of 29 –300 feet
36 points)
Moderate level of function for habitat (score of 150 feet
20-28 points)
High level of function for water quality 100 feet
improvement (24-32 points) and low for habitat
(less than 20 points)
Environment - Page 20
Not meeting any other characteristics100 feet
ii.Category II:
High level of function for habitat (score of 29 –300 feet
36 points)
Moderate level of function for habitat (score of 150 feet
20–28 points)
High level of function for water quality 100 feet
improvement and low for habitat (score for
water quality 24-32points and habitat less than
20 points)
Not meeting any other characteristics100 feet
iii.Category III:
Moderate level of function for habitat (score of 150 feet
20–28 points)
Not meeting above characteristic80 feet
iv.Category IV:
Score for all three basic functions less than 30 50 feet
points
b.Measurement of wetland buffers. All buffers shall be measured
from the wetland boundary as surveyed in the field. The width of
the wetland buffer shall be determined according to the wetland
category and the proposed land use. The buffer for a wetland
created, restored, or enhanced as compensation for approved
wetland alterations shall be the same as the buffer required for the
category of the created, restored, or enhanced wetland. Only fully
vegetated buffers will be considered. Lawns, walkways, driveways,
and other mowed or paved areas will not be considered buffers.
c.Increased wetland Buffer widths. The administrator shall require
increased buffer widths in accordance with the recommendations of
an experienced, qualified professional wetland scientist, and the
best available science on a case-by-case basis when a larger buffer
is necessary to protect wetland functions and values based on site-
specific characteristics. This determinationshall be based on one or
more of the following criteria:
i.A larger buffer is needed to protect other critical areas;
Environment - Page 21
ii.The buffer or adjacent uplands has a slope greater than 15
percent or is susceptible to erosion and standard erosion-control
measures will not prevent adverse impacts to the wetland; or
iii.The buffer area has minimal vegetative cover. In lieu of
increasing the buffer width where existing buffer vegetation is
inadequate to protect the wetland functions and values,
implementation of a buffer planting plan may substitute. Where
a buffer planting plan is proposed, it shall include densities that
are not less than three feet on center for shrubs and eight feet
on center for trees and require monitoring and maintenance to
ensure success. Existing buffer vegetation is considered
“inadequate” and will need to be enhanced through additional
native plantings and (if appropriate) removal of nonnative plants
when: (1) nonnative or invasive plant species provide the
dominant cover, (2) vegetation is lacking due to disturbance and
wetland resources could be adversely affected, or (3)
enhancement plantings in the buffer could significantly improve
buffer functions.
d.Wetland buffer width averaging. The administrator may allow
modification of the standard wetland buffer width in accordance
with an approved critical area report and the best available science
on a case-by-case basis by averaging buffer widths. Averaging of
buffer widths may only be allowed where a qualified professional
wetland scientist demonstrates that:
i.It will not reduce wetland functions or functional performance;
iii.The wetland contains variations in sensitivity due to existing
physical characteristics orthe character of the buffer varies in
slope, soils, or vegetation, and the wetland would benefit from a
wider buffer in places and would not be adversely impacted by a
narrower buffer in other places;
iv.The total area contained in the buffer area after averaging is no
less than that which would be contained within the standard
buffer; and
v.The buffer width is not reduced to less than 75percent of the
standard width or 35feet.
e.Buffer consistency. All mitigation sites shall have buffers consistent
with the buffer requirements of this chapter.
f.Buffer maintenance. Except as otherwise specified or allowed in
accordance with this chapter, wetland buffers shall be retained in
an undisturbed or enhanced condition. Removal of invasive
nonnative weeds is required for the duration of the mitigation
Environment - Page 22
bond.
g.Buffer uses. The following uses may be permitted within a wetland
buffer in accordance with the review procedures of this chapter;
provided they are not prohibited by any other applicable law and
they are conducted in a manner so as to minimize impacts to the
buffer and adjacent wetland:
i.Conservation and Restoration Activities. Conservation or
restoration activities aimed at protecting the soil, water,
vegetation, or wildlife.
ii.Passive Recreation. Passive recreation facilities designed and in
accordance with an approved critical area report.
G.Performance standards –compensatory mitigation requirements.
Compensatory mitigation for alterations to wetlands shall achieve
equivalent or greater biologicfunctions. Compensatory mitigation plans
shall be consistent with the state Department of Ecology Guidelines for
Developing Freshwater Wetlands Mitigation Plans and Proposals, 1994, as
revised.
1.Mitigation shall berequired in the following order of preference:
a.Avoiding the impact altogether by not taking a certain action or
parts of an action.
b.Minimizing impacts by limiting the degree or magnitude of the
action and its implementation, by using appropriate technology, or
by taking affirmative steps to avoid or reduce impacts.
c.Rectifying the impact by repairing, rehabilitating, or restoring the
affected environment.
d.Reducing or eliminating the impact over time by preservation and
maintenance operations.
e.Compensating for the impact by replacing, enhancing, or providing
substitute resources or environments.
2.Mitigation for lost or affected functions. Compensatory mitigation
actions shall address functions affected by the alteration to achieve
functional equivalency or improvement and shall provide similar
wetland functions as those lost, except when:
a.The lost wetland provides minimal functions as determined by a
site-specific function assessment, and the proposed compensatory
mitigation action(s) will provide equal or greater functions orwill
provide functions shown to be limiting within a watershed through
a formal Washington State watershed assessment plan or protocol;
or
Environment - Page 23
b.Out-of-kind replacement will best meet formally identified
watershed goals, such as replacement of historically diminished
wetland types.
3.Preference of mitigation actions. Mitigation actions that require
compensation by replacing, enhancing, or substitution shall occur in
the following order of preference:
a.Restoring wetlands on upland sites that were formerly wetlands.
b.Creating wetlands on disturbed upland sites such as those with
vegetative cover consisting primarily of nonnative introduced
species. This should only be attempted when there is a consistent
source of hydrology and it can be shown that the surface and
subsurface hydrologic regime is conducive for the wetland
community that is being designed.
c.Enhancing significantly degraded wetlands in combination with
restoration or creation. Such enhancement should be part of a
mitigation package that includes replacing the impacted area
meeting appropriate ratio requirements.
4.Type and location of mitigation. Unless it is demonstrated that a
higher level of ecological functioning would result from an alternate
approach, compensatory mitigation for ecological functions shall be
either in-kind and on-site, or in-kind and within the same stream
reach, sub basin, or drift cell. Mitigation actions shall be conducted
within the same sub drainagebasin and on the site as the alteration
except when the all of the following apply:
a.There are no reasonable on-site or in-sub drainagebasin
opportunities or on-site and in-sub drainagebasin opportunities do
not have a high likelihood of success, after a determination of the
natural capacity of the site to mitigate for the impacts.
Consideration should include: anticipated wetland mitigation
replacement ratios, buffer conditions and proposed widths,
hydrogeomorphic classes of on-site wetlands when restored,
proposed flood storage capacity, potential to mitigate riparian fish
and wildlife impacts (such as connectivity);
b.Off-site mitigation has a greater likelihood of providing equal or
improved wetland functions than the impacted wetland; and
c.Off-site locations shall be in the same sub drainagebasin unless:
i.Established watershed goals for water quality, flood or
conveyance, habitat, or other wetland functions have been
established and strongly justify location of mitigation at another
site; or
Environment - Page 24
ii.Credits from a state certified wetland mitigation bank are used
as mitigation and the use of credits is consistent with the terms
of the bank's certification.
5.Mitigation timing. Mitigation projects shall be completed with an
approved monitoring plan prior to activities that will disturb wetlands.
In all other cases, mitigation shall be completed immediately
following disturbance and prior to use or occupancy of the activity or
development. Construction of mitigation projects shall be timed to
reduce impacts to existing fisheries, wildlife, and flora.
The administratormay authorize a one-time temporary delay, up to
120days, in completing minor construction and landscaping when
environmental conditions could produce a high probability of failure or
significant construction difficulties. The delay shall not create or
perpetuate hazardous conditions or environmental damage or
degradation, and the delay shall not be injurious to the health,
safety, and general welfare of the public. The request for the
temporary delay must include a written justification that documents
theenvironmental constraints that preclude implementation of the
mitigation plan. The justification must be verified and approved by
the Cityand include a financial guarantee.
6.Mitigation ratios.
a.Acreage replacement ratios. The following ratios shall apply to
creation or restoration that is in-kind, is on-site, is the same
category, is timed prior to or concurrent with alteration, and has a
high probability of success. These ratios do not apply to remedial
actions resulting from unauthorized alterations; greater ratios shall
apply in those cases. These ratios do not apply to the use of credits
from a state certified wetland mitigation bank. When credits from a
certified bank are used, replacement ratios should be consistent
with the requirements of the bank's certification. The first number
specifies the acreage of replacement wetlands and the second
specifies the acreage of wetlands altered.
Category I6-to-1
Category II3-to-1
Category III2-to-1
Category IV1.5-to-1
b.Increased replacement ratio. The administrator may increase the
ratios under the following circumstances:
i.Uncertainty exists as to the probable success of the proposed
restoration or creation;
ii.A significant period of time will elapse between impact and
Environment - Page 25
replication of wetland functions;
c.Proposed mitigation will result in a lower category wetland or
reduced functions relative to the wetland being impacted; or
d.The impact was an unauthorized impact.
7.Wetlands enhancement as mitigation.
a.Impacts to wetland functions may be mitigated by enhancement of
existing significantly degraded wetlands, but must be used in
conjunction with restoration and/or creation. Applicants proposing
to enhance wetlands must produce a critical area reportthat
identifies how enhancement will increase the functions of the
degraded wetland and how this increase will adequately mitigate
for the loss of wetland area and function at the impact site. An
enhancement proposal must also show whether existing wetland
functions will be reduced by the enhancement actions.
b.At a minimum, enhancement acreage shall be double the acreage
required for creation or restoration. The ratios shall be greater
than double the required acreage where the enhancement proposal
wouldresult in minimal gain in the performance of wetland
functions and/or result in the reduction of other wetland functions
currently being provided in the wetland.
c.Mitigation ratios for enhancement in combination with other forms
of mitigation shall range from 6:1 to 3:1 and be limited to Class III
and Class IV wetlands.
H.Performance standards –land divisions. The division, redivision, or
adjusting of boundary lines of land in wetlands and associated buffers is
subject to the following:
1.Land that islocated wholly within a wetland or its buffer may not be
subdivided.
2.Land that is located partially within a wetland or its buffer may be
subdivided; provided, that an accessible and contiguous portion of
each new lot is:
a.Located outside of the wetland and its buffer; and
b.Meets the minimum lot size requirements of [locally adopted
zoning dimensions].
3.Access roads and utilities serving the proposed subdivision may be
permitted within the wetland and associated buffers only if the City
determinesthat no other feasible alternative exists and when
consistent with this chapter.
Environment - Page 26
18.21.070Critical aquifer recharge areas
A.Critical aquifer recharge areas designation. Critical aquifer recharge
areas are those areas with a critical recharging effect on aquifers used
for potable water as defined by Section365-190-030(2)WAC. A critical
aquifer recharge area has prevailing geologic conditions associated with
infiltration rates that create a high potential for contamination of ground
water resources or contribute significantly to the replenishment of
ground water.
B.Designation of critical aquifer recharge areas. The entire Cityof Yelm and
its urban growth area is identified as a highly susceptible critical aquifer
recharge area.
C.Performance standards –general requirements.
1.Activities may only be permitted in a critical aquifer recharge area if
the applicant can show that the proposed activity will not cause
contaminants to enter the aquifer and that the proposed activity will
not adversely affect the recharging of the aquifer.
2.The proposed activity must comply with the water source protection
requirements and recommendations of the U.S. Environmental
Protection Agency, Washington State Department of Health, and the
Thurston County Environmental Health Division.
3.All new development, redevelopment, and small parcel development
shall meet the water quality requirements of the stormwater manual
as adopted by the Cityof Yelm.
D.Performance standards –specific uses.
1.Storage tanks. All storage tanks proposed to be located in a critical
aquifer recharge area must comply with local building code
requirements and must conform to the following requirements:
a.Underground tanks. All new underground storage facilities
proposed for use in the storage of hazardous substances or
hazardous wastes shall be designed and constructed so as to:
i.Prevent releases due to corrosion or structural failure for the
operational life of the tank;
ii.Be protected against corrosion, constructed of noncorrosive
material, steel clad with a noncorrosive material, or designed to
include a secondary containment system to prevent the release
or threatened release of any stored substances; and
iii.Use material in the construction or lining of the tank that is
compatible with the substance to be stored.
b.Aboveground tanks. All new aboveground storage facilities
Environment - Page 27
proposed for use in the storage of hazardous substances or
hazardous wastes shall be designed and constructed so as to:
i.Not allow the release of a hazardoussubstance to the ground,
ground waters, or surface waters;
ii.Have a primary containment area enclosing or underlying the
tank or part thereof; and
iii.A secondary containment system either built into the tank
structure or a dike system built outside the tank for all tanks.
2.Vehicle repair and servicing.
a.Vehicle repair and servicing must be conducted over impermeable
pads and within a covered structure capable of withstanding
normally expected weather conditions. Chemicals used in the
process of vehicle repair and servicing must be stored in a manner
that protects them from weather and provides containment should
leaks occur.
b.No dry wells shall be allowed in critical aquifer recharge areas on
sites used for vehicle repair and servicing. Dry wells existing on the
site prior to facility establishment must be abandoned using
techniques approved by the state Department of Ecology prior to
commencement of the proposed activity.
3.Use of reclaimed water for surface percolation or direct recharge.
Water reuse projects for reclaimed water must be in accordance with
the adopted water or sewer Comprehensive Plans that have been
approved by the state Departments of Ecology and Health.
a.Use of reclaimed water for surface percolation must meet the
ground water recharge criteria given in Sections90.46.010(10)
and 90.46.080(1)RCW. The state department of ecology may
establish additional discharge limits in accordance with Section
90.46.080(2) RCW.
b.Direct injection must be in accordance with the standards
developed by authority of Section90.46.042RCW.
18.21.080Frequently flooded areas
A.Designation of frequently flooded areas. Frequently flooded areas shall
include areas identified bythe Flood Insurance Rate Map(s) and areas
mapped by Thurston County as high ground water flood hazard areas.
The flood insurance maps and high ground water maps are hereby
adopted by reference, declared part of this chapter, and are available for
public review at the City.
Environment - Page 28
B.Flood elevation data. When base flood elevation data is not available (A
and V zones), the administrator shall obtain, review, and reasonably
utilize any base flood elevation and floodway data available from a
federal, state, or other official source, in order to administer this chapter.
C.Maintenance of records. Where base flood elevation data is provided
through the flood insurance study or required through this chapter, the
administrator shall obtain and record the flood elevation certificates of all
new or substantially improved structures, and whether or not the
structure contains a basement. The administrator shall also maintain for
public inspection all records of floodplain hazards, certificates of flood
proofing, and flood elevation data.
D.Performance standards –general requirements. The following standards
shall be adhered to in all frequently flooded areas, except as otherwise
provide for in this chapter.
1.Approval of work in a frequently flooded area. Prior to any clearing,
grading, dumping, drilling, dredging, filling, or the construction or
reconstruction of any structure, the Cityshall have approved through
the underlying permit or through approval of a critical areas report
that the standards for development within a frequently flooded area
have been met.
2.No activity within a frequently flooded area shall increase the base
flood elevation.
E.Performance standards –general requirements in FEMA Designated 100-
Year Floodplain.
1.Structures shall belocated outside the floodplain. All structures,
utilities, and other improvements shall be located on the buildable
portion of the site out of the floodplain unless there is no buildable
site area out of the floodplain. For sites with no buildable area out of
the floodplain, structures, utilities, and other improvements shall be
placed on the highest land on the site, oriented parallel to flow rather
than perpendicular, and sited as far from the watercourse and other
critical areas as possible. If the administrator detects any evidence of
active hyporheic exchange on a site, the developmentshall be
located to minimize disruption of such exchange.
2.Methods that minimize flood damage. All new construction and
substantial improvements shall be constructed using flood resistant
materials and using methods and practices that minimize flood
damage.
3.Utility protection. Electrical, heating, ventilation, plumbing, air-
conditioning equipment, and other service facilities shall be designed
and/or otherwise elevated or located so as to prevent water from
Environment - Page 29
entering or accumulating within the components during conditions of
flooding.
4.Elevation certificate following construction. Following construction of
a structure within the floodplain where the base flood elevation is
provided, the applicant shall obtain an elevation certificate that
records the elevation of the lowest floor. The elevation certificate
shall be completed by a surveyor or engineer licensed in the state of
Washington and shall be submitted to the Cityfor recording.
5.Anchoring.
a.Anchoring requirement. All new constructionand substantial
improvements within the floodplain shall be anchored to prevent
flotation, collapse, or lateral movement of the structure.
b.Manufactured homes. All manufactured homes placed within the
floodplain must be anchored to prevent flotation, collapse, or
lateral movement and shall be installed using methods and
practices that minimize flood damage. Anchoring methods may
include, but are not limited to, use of over-the-top or frame ties to
ground anchors(reference FEMA P-85 :protecting Manufactured
Homes from Floods and Other Hazards” guidebook for additional
techniques).
6.Fill and grading. Fill and grading with the floodplain shall only occur
after a determination that the fill or grading will not block side
channels, inhibit channel migration, increase the base flood elevation,
or be within a channel migration zone.
F.Performance standards –specific uses in the FEMA designated 100-Year
floodplain. Specific uses shall adhere to the following relevant standards,
in addition to the general standards.
1.Divisions of land.
a.All new divisions of land, including subdivisions, short subdivisions,
boundary line adjustments, binding site plans, and master planned
communities shall not create any building lot for commercial or
residential purposes with any portion within the floodplain.
b.Floodplain areas shall be dedicated as open space.
c.No infrastructure required for the subdivision with the exception of
utility transport lines identified by the appropriate utility capital
facilities plan shall be located within the floodplain.
d.Subdivisions and short subdivisions shall be designed to minimize
or eliminate flood damage and impacts to floodplain functions and
values. Public utilities and facilities that are installed as part of
Environment - Page 30
such subdivisions, such as sewer, gas, electrical, and water
systems, shall be located and constructed to also minimize flood
damage and impacts to floodplain functions and values.
Subdivisions should be designed using natural features of the
landscape and should not incorporate flood protection changes.
e.Subdivisions and short subdivisions shall have adequate natural
surface water drainage to reduce exposure to flood hazards; and
f.Subdivisions and short subdivisions shall show the 100-year
floodplain, floodway, and channel migration zone on the
preliminary and final plat and short plat maps and designate such
areas as “no build,” when applicable.
2.Utilities.
a.Infiltration of flood waters. All new and replacement water supply
systems shall be designed to minimize or eliminate infiltration of
flood waters into the systems.
b.Sanitary sewage systems. New and replacement sanitary sewage
systems shall be designed to minimize or eliminate infiltration of
flood waters into the systems and discharges from the systems
into flood waters.
c.On-site waste disposal systems. On-site waste disposal systems
shall be located to avoid impairment to them or contamination
from them during flooding. New on-site sewage disposal systems
are prohibited within the floodplain.
3.Residentialconstruction on lots created prior to 1999.
a.Must be above base flood elevation. New construction and
substantial improvement of any residential structure shall have the
lowest floor, including basement, elevated one foot or more above
the base flood elevation.
b.Areas below the lowest floor. Fully enclosed areas below the lowest
floor that are subject to flooding shall only be allowed when
designed to automatically equalize hydrostatic flood forces on
exterior walls by allowing for the entry and exitof floodwaters.
Designs for meeting this requirement must either be certified by a
registered professional engineer or architect or must meet or
exceed the following minimum criteria:
i.A minimum of two openings having a total net area of not less
than one square inch for every square foot of enclosed area
subject to flooding shall be provided;
ii.The bottom of all openings shall be no higher than one foot
Environment - Page 31
above grade; and
iii.Openings may be equipped with screens, louvers, or other
coverings or devices;providedthat they permit the automatic
entry and exit of floodwaters.
c.Manufactured homes must be elevated. All manufactured homes
to be placed or substantially improved shall be elevated on a
permanent foundation such that the lowest floor of the
manufactured home is elevated one foot or more above the base
flood elevation and be securely anchored to an adequately
anchored foundation system to resist flotation, collapse, and
lateral movement.
4.Nonresidential construction on lots created prior to 1999.
a.Above base flood elevation. New construction and substantial
improvement of any commercial, industrial, or other nonresidential
structure shall either have the lowest floor, including basement,
elevated one foot or more above the base flood elevation, or,
together with attendant utility and sanitary facilities, shall:
i.Be floodproofed so that below one foot or more above the base
flood level the structure is watertight with walls substantially
impermeable to the passage of water;
ii.Have structural components capable of resisting hydrostatic and
hydrodynamic loads and effects of buoyancy; and
iii.Be certified by a registered professional engineer or architect
that the design and methods of construction are in accordance
with accepted standards of practice for meeting provisions of this
subsection based on their development and/or review of the
structural design, specifications, and plans.
b.Areas below the lowest floor. Fully enclosed areas below the lowest
floor that are not floodproofed shall be designed to automatically
equalize hydrostatic flood forces on exterior walls by allowing for
the entry and exit of floodwaters. Designs for meeting this
requirement must either be certified by a registered professional
engineer or architect, or must meet or exceed the following
minimum criteria:
i.A minimum of two openings having a total net area of not less
than one square inch for every square foot of enclosed area
subject to flooding shall be provided;
ii.The bottom of all openings shall be no higher than one foot
above grade; and
Environment - Page 32
iii.Openings may be equipped with screens, louvers, or other
coverings or devices; providedthat they permit the automatic
entry and exit of floodwaters.
G.Performance standards –general requirements in high ground water
hazard areas.
1.Flood elevations. The base flood elevation for high ground water flood
hazard areas corresponds to the elevation of the outer edge of the
high ground water flood hazard area.
2.Delineation of the base flood elevation. Applicants shall submit to the
approval authority hydrologic and hydrogeologic studies as necessary
to delineate the high ground water flood hazard area and the base
flood elevation.
3.No development shall locate within 50feet, measured on a horizontal
plane, from the outer edge of the high ground water hazard area or
extending to a ground elevation two feet above the base flood
elevation, whichever is less.
4.The bottom of any infiltration facility for stormwater discharge shall
be located at least sixfeet above the base flood elevation.
H.Uses and activities prohibited from frequently flooded areas.
1.Critical facilities. Critical facilities are prohibited from frequently
flooded areas to prevent damage to such facilities, to avoid costs that
will be incurred by the public, and to maintain functionality of such
facilities during flood events. If such a prohibition is unreasonable, an
allowance for critical facilities in frequently flooded areas with the
following specific conditions:
a.Construction of new critical facilities shall be permissible within
frequently flooded areas if no feasible alternative site is available.
b.Critical facilities constructed within frequently flooded areas shall
have the lowest floor elevated three feet or more above the level
of the base flood elevation (100-year flood).
c.Floodproofing and sealing measures must be taken to ensure that
toxic substances will not be displaced by or released into flood
waters.
d.Access routes elevated to or above the level of the base flood
elevation shall be provided to all critical facilities to the extent
possible.
2.Wells used for potable water. Water wells shall be located on high
ground and are prohibited from being within the floodway.
3.On-site sewage disposal systems. On-site sewage disposal systems
Environment - Page 33
are prohibited from the floodway, the channel migration zone, and
the 10-year floodplain elevation.
18.21.090Flood Damage Protection
A.The flood hazard areas of Yelm are subject to periodic inundation which
results in loss of life and property, health, and safety hazards, disruption
of commerce and governmental services, extraordinary public
expenditures for flood protection and relief and impairment of the tax
base, all of which adversely affect the public health, safety, and general
welfare.
These flood losses are caused by the cumulative effect of obstructions in
areas of special flood hazards which increase flood heights and velocities,
and when inadequately anchored, damage uses in other areas. Uses that
are inadequately floodproofed, elevated, or otherwise protected from
flood damage also contribute to the flood loss.
B.Methods of reducing flood losses.In order to accomplish its purposes,
this chapter includes methods and provisions for:
1.Restricting or prohibiting uses which are dangerous to health, safety,
and property due to water or erosion hazards, or which result in
damaging increases in erosion or in flood heights or velocities;
2.Requiring that uses vulnerable to floods, including facilities which
serve such uses, be protected against flood damage at the time of
initial construction;
3.Controlling the alteration of natural floodplains, stream channels, and
natural protective barriers, which help accommodate or channel
floodwaters;
4.Controlling filling, grading, and other development which may
increase flood damage; and
5.Preventing or regulating the construction of flood barriers which will
unnaturally divert floodwaters or may increase flood hazards in other
areas.
C.General provisions.Basis for establishing the areas ofspecial flood
hazard.The areas of special flood hazard identified by the Federal
Insurance Administration in a scientific and engineering report entitled
“The Flood Insurance Study for Thurston County, Washington and
Incorporated Areas dated October 16,2012,” as amended, with an
accompanying Flood Insurance Rate Map, as amended, are hereby
adopted by reference and declared to be a part of this chapter. The Flood
Insurance Study and the FIRM are on file at Yelm City Hall, 105 Yelm
Avenue West, Yelm, Washington. When base flood elevation data has not
been provided, the Community Development Department shall obtain
Environment - Page 34
and reasonably utilize any base flood elevation and floodway data
available from federal, state or other source.
D.Penalties for noncompliance.Nostructure or land shall hereafter be
constructed, located, extended, converted, or altered without full
compliance with the terms of this chapter and other applicable
regulations. Violation of the provisions of this chapter by failure to
comply with any of its requirements (including violations of conditions
and safeguards established in connection with conditions) shall constitute
a misdemeanor. Nothing herein contained shall prevent the Cityfrom
taking such other lawful action as is necessary to prevent or remedy any
violation.
E.Abrogation and greater restrictions. Thischapter is not intended to
repeal, abrogate, or impair any existing easements, covenants, or deed
restrictions. However, where this chapter and another ordinance,
easement, covenant,or deed restriction conflict or overlap, whichever
imposes the more stringent restrictions shall prevail.
F.In the interpretation and application of this chapter, all provisions shall
be:
1.Considered as minimum requirements;
2.Liberally construed in favor of the governing body;
3.Deemed neither to limit nor repeal any other powers granted under
state statutes.
G.Warning and disclaimer of liability. Thedegree of flood protection
required by this chapter is considered reasonable for regulatory purposes
and is based on scientific and engineering considerations. Larger floods
can and will occur on rare occasions. Flood heights may be increased by
manmade or natural causes. This chapter does not imply that land
outside the areas of special flood hazards or uses permitted within such
areas will be free from flooding or flood damages. This chapter shall not
create liability on the part of the City, any officer or employee thereof, or
the Federal Insurance Administration, for any flood damages that result
from reliance on this chapter or any administrative decision lawfully
made hereunder.
H.The Community Development Departmentis appointed to administer and
implement this chapter by granting or denying development permit
applications in accordance with its provisions.
I.Duties of the Community Development Departmentshall include, but not
be limited to:
1.Permit Review.
Environment - Page 35
a.Review all development permits to determine that the permit
requirements of this chapter have been satisfied;
b.Review all development permits to determine that all necessary
permits have been obtained from those federal, state or local
governmental agencies from which prior approval is required;
c.Review all development permits to determine if the proposed
development is located in the floodway. If located in the floodway,
assure that the provisions of Chapter18.21 YMCare met;
2.Information to be obtained and maintained.
a.Where base flood elevation data is provided through the Flood
Insurance Study or required as in subsection B of this section,
obtain and record the actual (as-built) elevation (in relation to
mean sea level) of the lowest floor, including basement, of all
new or substantially improved structures, and whether or not the
structure contains a basement;
b.For all new or substantially improved floodproofed nonresidential
structures where base flood elevation data is provided through
the FIS, FIRM, or as required in subsection B of this section:
i.Verify and record the actual elevation (in relation to mean sea
level) to which the structure was floodproofed; and
ii.Maintain the floodproofing certifications required inSection
18.11.080 YMC.
c.Maintain for public inspection all records pertaining to the
provisions of this chapter;
3.Alteration of watercourses.
a.Notify adjacent communities and the Washington State
Department of Ecology prior to any alteration or relocation of a
watercourse, and submit evidence of such notification to the
Federal Insurance Administration;
b.Require that maintenanceis provided within the altered or
relocated portion of said watercourse so that the flood-carrying
capacity is not diminished;
4.Interpretation of FIRM boundaries. Make interpretations where
needed, as to exact location of the boundaries of the areas of special
flood hazards (for example, where there appears to be a conflict
between a mapped boundary and actual field conditions). The person
contesting the location of the boundary shall be given a reasonable
opportunity to appeal the interpretations providedin Section 18.14
YMC.
Environment - Page 36
J.Provisions for Flood hazard reduction
1.General standards.In all areas of special flood hazards, the
standards set out in Section 18.21.080YMCare required.
K.Water wells shall be located on high ground that is not in the floodway.
L.Subdivision proposals.
1.All subdivision proposals shall be consistent with the need to
minimize flood damage.
2.All subdivision proposals shall have public utilities and facilities such
as sewer, gas, electrical, and water systems located and constructed
to minimize flood damage.
3.All subdivision proposals shall have adequate drainage provided to
reduce exposure to flood damage.
4.Where base flood elevation data has not been provided or is not
available from another authoritativesource, it shall be generated for
subdivision proposals and other proposed developments which
contain at least 50lots or five acres, whichever isless.
M.Review of building permits.
1.Where elevation data is not available either through the Flood
Insurance Study or from another authoritative source, applications
for building permits shall be reviewed to assure that proposed
construction will be reasonably safe from flooding. The test of
reasonableness is a local judgment and includes use of historical
data, high water marks, photographs of past flooding, etc., where
available. Failure to elevate at least two feet above grade in these
zones may result in higher insurance rates.
N.Tap-in restrictions.
1.Applicability. Tap-in restrictions apply to lands mapped by FEMA
(Federal Emergency Management Act) as 100-year floodplains,
identified as of RD (U.S. Department of Agriculture Rural
Development) funding obligation date, July 30, 1997. Tap-in
restrictions will be enforced to deny future sewer connections to the
system, when verification is not made by applicants that planned
improvements to properties requesting connection to the system will
be constructed outside the 100-year floodplain.
2.Exceptions. An exclusion to these tap-in restrictions will be granted
for:
a.All road and utility crossing set forth in the:
i.Yelm comprehensive transportation plan (August 1992),
Environment - Page 37
ii.Yelm water reuse project (July 1995),
iii.Yelm comprehensive water plan (August 1992), and
iv.The private utility planning for Yelm area (for electricity, gas,
telephone, cable), as excerpted in Appendix G to the Yelm
Comprehensive Plan(February 1995);
b.All property within the Thurston Highlands Southwest Yelm
conceptual master plan, as approvedOctober 12, 1994;
c.All lands identified after July 30, 1997 by FEMA as 100-year
floodplains;
d.Lots of record within the Cityas described and depicted in
Ordinance 595, dated January 8, 1997; and
e.Such other exceptions meeting the criteria identified in subsection
(C)(3) of this section.
2.Administration.An applicant may request from the Cityan
administrative waiver of the tap-in restriction, where:
a.It is necessary to meet the Yelm Comprehensive Plangoals and
policies, and
b.The development will not result in risk to persons or property
during periods of flood conditions.
3.If the Cityrecommends a waiver, such recommendation shall be
submitted to RD where the decision on the waiver shall become final.
O.Nonresidential construction. Allnonresidential construction shall have
structural components capable of resisting hydrostatic and hydrodynamic
loads and effects of buoyancy, and becertified by a registered
professional engineer or architect that the design and methods of
construction are in accordance with accepted standards of practice for
meeting provisions of this section based on their development and/or
review of the structural design, specifications and plans.
Applicants floodproofing nonresidential buildings shall be notified that
flood insurance premiums will be based on rates that are one foot below
the floodproofed level (e.g., a building floodproofed to one foot above the
base flood level will be rated as at the base flood level).
P.Critical facility.Construction of new critical facilities shall be, to the
extent possible, located outside the limits of the area of special flood
hazard. Construction of new or critical facilities shall be permissible
within the area of special flood hazard if no feasible alternative site is
available. Critical facilities constructed within the area of special flood
hazard shall have the lowest floor elevated to three feet or more above
the level of the base flood elevation at the site. Floodproofing and sealing
Environment - Page 38
measures must be taken to ensure that toxic substances will not be
displaced by or released into floodwaters. Access routes elevated to or
above the level of the base floodplain shall be provided to all critical
facilities to the extent possible.
Q.Recreational vehicles.Recreational vehicles placed on sites within zones
A1 through A30 and AE on the community’s FIRM shall either:
1.Be on the site for fewer than 14consecutive days; and
2.Be fully licensed and ready for highway use, on their wheels or
jacking system, be attached to the site only by quick-disconnect-type
utilities and security devices, and have no permanently attached
additions; or
3.Meet the requirements ofSection 18.21.080 YMCand the elevation
and anchoring requirements for manufactured homes.
R.Floodways.Located within areas of special flood hazard established in
Chapter 18.21 YMCare areas designated as floodways. Since the
floodway is an extremely hazardous area due to the velocity of
floodwaters which carry debris, potential projectiles, and erosion
potential, the following provisions apply:
1. Prohibit encroachments, including fill, new construction, substantial
improvements, and other development unless certification by a
registered professional engineer or architect is provided
demonstrating through hydrologic and hydraulic analyses performed
in accordance with standard engineering practice that the proposed
encroachments shall not result in any increase in flood levels during
the occurrence of base flood discharge;
2. Construction or reconstruction of residential structures is prohibited
within designated floodways, except for:
a.Repairs, reconstruction, or improvements to a structure, which do
not increase the ground floor area; and
b.Repairs, reconstruction or improvements to a structure, the costof
which does not exceed 50percent of the market value of the
structure either:
i.Before the repair or reconstruction is started; or
ii.If the structure has been damaged, and is being restored, before
the damage occurred.
iii.Work done on structures to comply with existing violations of
state or local health, sanitary, or safety code specifications which
have been identified by the administrator and which are the
minimum necessary to assure safe living conditions or to
Environment - Page 39
structures identified as historic places shall not be included in the
50percent determination;
3.If subsection A of this section is satisfied, all new construction and
substantial improvements shall comply with all applicable flood
hazard reduction provisions ofArticle VI of this chapter.
S.Areas with base flood elevations but no floodways.AE and A1-30 Zone
with Base Flood Elevations but No Floodways. In areas with base flood
elevations (but a regulatory floodway has not been designated), no new
construction, substantial improvements, or other development (including
fill) shall be permitted within zone AE on the community’s FIRM, unless it
is demonstrated that the cumulative effect of the proposed development,
when combined with all other existing and anticipated development, will
not increase the water surface elevation of the base flood more than one
foot at any point within the community.
T.Wetlands management.To the maximum extent possible, in order to
avoid the short-and long-term adverse impacts associated with the
destruction or modification of wetlands, especially those activities which
limit or disrupt the ability of the wetland to alleviate flooding impacts,
the following process should be implemented:
1.Review proposals for development within areas of special flood
hazard for their possible impacts on wetlands located within the
floodplain;
2.Ensure that development activities in or around wetlands do not
negatively affect public safety, health and welfare by disrupting the
wetlands’ ability to reduce flood and storm drainage;
3.Request technical assistance from the Department of Ecology in
identifying wetland areas. Existing wetland map information from the
National Wetlands Inventory (NWI) can be used in conjunction with
the community’s FIRM to prepare an overlay zone indicating critical
wetland areas deservingspecial attention.
18.21.100Geologically hazardous areas
A.Designation of geologically hazardous areas. Geologically hazardous
areas include areas susceptible to erosion, sliding, earthquake, or other
geological events. They pose a threat to the health and safety of citizens
when incompatible development is sited in areas of significant hazard.
Such incompatible development may not only place itself at risk, but also
may increase the hazard to surrounding development and use.
B.Designation of specific hazard areas
1.Erosion hazard areas. Erosion hazard areas are at least those areas
identified by the U.S. Department of Agriculture's Natural Resources
Environment - Page 40
Conservation Service as having a “moderate to severe,” “severe,” or
“very severe” rill and inter-rill erosion hazard. Rill or inter-rill are
areas subject to sheet wash, or steep-sided channels resulting from
accelerated erosion. Erosion hazard areas are also those areas
impacted by shore land and/or streambank erosion and those areas
within a river's channel migration zone.
2.Landslidehazard areas. Landslide hazard areas are areas potentially
subject to landslides based on a combination of geologic,
topographic, and hydrologic factors. They include areas susceptible
because of any combination of bedrock, soil, slope (gradient), slope
aspect, structure, hydrology, or other factors. Examples of these may
include, but are not limited to, the following:
a.Areas of historic failures;
b.Areas with all three of the following characteristics:
i.Slopes steeper than 15percent;
ii.Hillsides intersecting geologic contacts with a relatively
permeable sediment overlying a relatively impermeable
sediment or bedrock; and
iii.Springs or ground water seepage;
c.Areas that have shown movement during the Holocene epoch
(from 10,000 years ago to the present) or that are underlain or
covered by mass wastage debris of that epoch;
d.Slopes that are parallel or subparallel to planes of weakness (such
as bedding planes, joint systems, and fault planes) in subsurface
materials;
e.Slopes having gradients steeper than 80percent, subject to rock
fall during seismic shaking;
f.Areas potentially unstable because of rapid stream incision,
streambank erosion, and undercutting by wave action;
g.Areas that show evidence of, or are at risk from snow avalanches;
h.Areas located in a canyon or on an active alluvial fan, presently or
potentially subject to inundation by debris flows or catastrophic
flooding; and
i.Any area with a slope of 40percent or steeper and with a vertical
relief of 10or more feet, except areas composed of consolidated
rock. A slope is delineated by establishing its toe and top and is
measured by averaging the inclination over at least 10feet of
vertical relief.
Environment - Page 41
3.Seismic hazard areas. Seismic hazard areas are areas subject to
severe risk of damage as a result of earthquake induced ground
shaking, slope failure, settlement, soil liquefaction, lateral spreading,
or surface faulting. One indicator of potential for future earthquake
damage is a record of earthquake damage in the past. Ground
shaking is the primary cause of earthquake damage in Washington.
The strength of ground shaking is primarily affected by:
a.The magnitude of an earthquake;
b.The distance from the source of an earthquake;
c.The type of thickness ofgeologic materials at the surface; and
d.The type of subsurface geologic structure.
C.Mapping of geologically hazardous areas.
1.The approximate location and extent of geologically hazardous areas
are shown on the adopted critical area maps.
2.These maps are to be used as a guide for the City, project applicants
and/or property owners and may be continuously updated as new
critical areas are identified. They are a reference and do not provide a
final critical area designation.
D.Performance standards –general requirements.
1.Alterations of geologically hazardous areas or associated buffers may
only occur for activities that:
a.Will not increase the threat of the geological hazard to adjacent
properties beyond pre-development conditions;
b.Will not adversely impact other critical areas;
c.Are designed so that the hazard to the project is eliminated or
mitigated to a level equal to or less than pre-development
conditions; and
d.Are certified as safe as designed and under anticipated conditions
by a qualified engineer or geologist, licensed in the state of
Washington.
2.Critical facilities prohibited. Critical facilities shall not be sited within
geologically hazardous areas unless there is no other practical
alternative.
3.Buffer requirement. A buffer shall be established from all edges of
landslide hazard areas. The size of the buffer shall be determined by
the administrator to eliminate or minimize the risk of property
damage, death, or injury resulting from landslides caused in whole or
part by the development, based upon review of and concurrence with
Environment - Page 42
a critical area report prepared by a qualified professional.
a.Minimum buffer. The minimum buffer shall be equal to the height
of the slope.
b.Buffer reduction. The buffer may be reduced to a minimum of 10
feet when a qualified professional demonstrates to the
administrator's satisfaction that the reduction will adequately
protect the proposed development, adjacent developments and
uses, and the subject critical area.
c.Increased buffer. The buffer may be increased where the
administrator determines a larger buffer is necessary to prevent
risk of damage to proposed and existing development;
4.Alterations. Alterations of an erosion or landslide hazard area and/or
buffer may only occur for activities for which a hazards analysis is
submitted and certifies that:
a.The development will not increase surface water discharge or
sedimentation to adjacent properties beyond pre-development
conditions;
b.The development will not decrease slope stability on adjacent
properties; and
c.Such alterations will not adversely impact other critical areas.
5.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.
6.Seasonal restriction. Clearing shall be allowed only from May 1st to
October 1st of each year; provided, that the Citymay extend or
shorten the dry season on a case-by-case basis depending on actual
weather conditions, except that timber harvest, not including brush
clearing or stump removal, may be allowed pursuant to an approved
forest practice permit issued by the Cityor the Washington State
Department of Natural Resources.
7.Utility lines and pipes. Utility lines and pipes shall be permitted in
erosion and landslide hazard areas only when the applicant
demonstrates that no other practical alternative is available. The line
or pipe shall be located above ground and properly anchored and/or
designed so that it will continue to function in the event of an
underlying slide. Stormwater conveyance shall be allowed only
through a high-density polyethylene pipe with fuse-welded joints, or
similar product that is technically equal or superior.
8.Point discharges. Point discharges from surface water facilities and
Environment - Page 43
roof drains onto or upstream from an erosion or landslide hazard area
shall be prohibited.
9.Division of land. The division of land in landslide hazard areas and
associated buffers is subject to the following:
a.Land that is located wholly within a landslide hazard area or its
buffer may not be subdivided. Land that is located partially within
a landslide hazard area or its buffer may be divided; provided, that
each resulting lot has sufficient buildable area outside of, and will
not affect, the landslide hazard or its buffer.
b.Access roads and utilities may be permitted within the landslide
hazard area and associated buffers if the Citydetermines that no
other feasible alternative exists; and
E.Prohibited development. On-site sewage disposal systems, including
drain fields, shall be prohibited within erosion and landslide hazard areas
and related buffers.
18.21.110Fish and wildlife habitat conservation areas
A.Designation of fish and wildlife habitat conservation areas.
1.Fish and wildlife habitat conservation areasare areas necessary for
maintaining species in suitable habitats within their natural
geographic distribution so that isolated subpopulationsare not
created as designated by Section 365-190-080(5) WAC. These areas
include:
a.Areas with which state or federally designated endangered,
threatened, and sensitive species have a primary association;
i.Areas with which state or federally designated endangered,
threatened, and sensitive specieshave a primary association.
ii.State designated endangered, threatened, and sensitive are
those fish and wildlife species native to the state of Washington
identified by the Washington Department of Fish and Wildlife
that are in danger of extinction, threatened to become
endangered, vulnerable, or declining and are likely to become
endangered or threatened in a significant portion of the range
within the state without cooperative management or removal of
threats.
bState priority habitats and areas associatedwith state priority
species. Priority habitats and species are considered to be priorities
for conservation and management. Priority species require
protective measures for their perpetuation due to their population
status, sensitivity to habitat alteration, and/or recreational,
Environment - Page 44
commercial, or tribal importance. Priority habitats are those habitat
types or elements with unique or significant value to a diverse
assemblage of species. A priority habitat may consist of a unique
vegetation type or dominant plant species, a described
successional stage, or a specific structural element. Priority
habitats and species are identified by the state Department of Fish
and Wildlife.
c.Naturally occurring ponds Under 20Acres. Naturally occurring
ponds are those ponds under 20acres and their submerged
aquatic beds that provide fish or wildlife habitat, including those
artificial ponds intentionally created from dry areas in order to
mitigate impacts to ponds. Naturally occurring ponds do not
include ponds deliberately designed and created from dry sites,
such as canals, detention facilities, wastewater treatment facilities,
farm ponds, temporary construction ponds, and landscape
amenities, unless such artificial ponds were intentionally created
for mitigation.
d.Waters of the state. Waters of the state include lakes, rivers,
ponds, streams, inland waters, underground waters, salt waters,
and all other surface waters and watercourses within the
jurisdiction of the state of Washington.
e.Areas of rare plant species and high quality ecosystems. Areas of
rare plant species and high quality ecosystems are identified by the
Washington State Department of Natural Resources through the
Natural Heritage Program.
f.Land useful oressential for preserving connections between habitat
blocks and open spaces.
2.All areas within the Citymeeting one or more of these criteria,
regardless of any formal identification, are hereby designated critical
areas and are subject to the provisions of this chapter and shall be
managed consistent with the best available science.
3.Mapping. The approximate location and extent of habitat
conservation areas are shown on the critical area maps adopted by
the City.
C.Performance standards –general requirements.
1.Nonindigenous species. No plant, wildlife, or fish species not
indigenous to the region shall be introduced into a habitat
conservation area unless authorized by a state or federal permit or
approval.
2.Mitigation and contiguous corridors. Mitigation sites shall be located
Environment - Page 45
to preserve or achieve contiguous wildlife habitat corridors in
accordance with a mitigation plan that is part of an approved critical
area report to minimize the isolating effects of development on
habitat areas, so long as mitigation of aquatic habitat is located
within the same aquatic ecosystem as the area disturbed.
3.Approvals of activities. The administrator shall condition approvals of
activities allowed within or adjacent to a habitat conservation area or
its buffers, as necessary to minimize or mitigate any potential
adverse impacts. Conditions shall be based on the best available
science and may include, but are not limited to, the following:
a.Establishment of buffer zones;
b.Preservation of critically important vegetation and/or habitat
features such as snags and downed wood;
c.Limitation of access to the habitat area, including fencing to deter
unauthorized access;
d.Seasonal restriction of construction activities;
e.Establishment of a duration and timetable for periodic review of
mitigation activities; and
f.Requirement of a performance bond, when necessary, to ensure
completion and success of proposed mitigation.
4.Mitigation and equivalent or greater biological functions. Mitigation of
alterations to habitat conservation areas shall achieve equivalent or
greater biologic and hydrologic functions and shall include mitigation
for adverse impacts upstream or downstream of the development
proposal site. Mitigation shall address each function affectedby the
alteration to achieve functional equivalency or improvement on a per
function basis.
5.Approvals and the best available science. Any approval of alterations
or impacts to a habitat conservation area shall be supported by the
best available science.
6.Buffers
a.Establishment of buffers. The administrator shall require the
establishment of buffer areas for activities adjacent to habitat
conservation areas when needed to protect habitat conservation
areas. Buffers shall consist of an undisturbed area of native
vegetation or areas identified for restoration established to protect
the integrity, functions, and values of the affected habitat.
Required buffer widths shall reflect the sensitivity of the habitat
and the type and intensity of human activityproposed to be
Environment - Page 46
conducted nearby and shall be consistent with the management
recommendations issued by the Washington Department of Fish
and Wildlife. Habitat conservation areas and their buffers shall be
preserved in perpetuity through the use of native growth
protection areas and critical area tracts.Native growth protection
areas includes area where native vegetation is preserved for the
purpose of preventing harm to property and the environment
including, but not limited to, controlling surface water runoff and
erosion, maintaining slope stability, buffering, and protecting
plants and animal habitat.
b.Seasonal restrictions. When a species is more susceptible to
adverse impacts during specific periods of the year, seasonal
restrictions may apply. Larger buffers may be required and
activities may be further restricted during the specified season.
c.Habitat buffer averaging. The administrator may allow the
recommended habitat area buffer width to be reduced in
accordance with a critical area report, thebest available science,
and the management recommendations issued by the Washington
Department of Fish and Wildlife, only if:
i.It will not reduce stream or habitat functions;
ii.It will not adversely affect salmonid habitat;
iii.It will provide additional natural resource protection, such as
buffer enhancement;
iv.The total area contained in the buffer area after averaging is no
less than that which would be contained within the standard
buffer; and
v.The buffer area width is not reduced by more than25percent in
any location.
7.Divisions of land. The subdivision and short subdivision of land in fish
and wildlife habitat conservation areas and associated buffers is
subject to the following:
a.Land that is located wholly within a habitat conservation area or its
buffer may not be subdivided.
b.Land that is located partially within a habitat conservation area or
its buffer may be divided; provided, that the developable portion of
each new lot and its access is located outside of the habitat
conservation area or its buffer and meets the minimum lot size
requirements.
c.Access roads and utilities serving the proposed may be permitted
Environment - Page 47
within the habitat conservation area and associated buffers only if
the Citydetermines that no other feasible alternative exists and
when consistent with this chapter.
D.Performance standards –specific habitats.
1.Endangered, threatened, and sensitive species.
a.No development shall be allowed within a habitat conservation area
or buffer with which state or federally endangered, threatened, or
sensitive species have a primary association, except that which is
provided for by a management plan established by the Washington
Department of Fish and Wildlife or applicable state or federal
agency.
b.Whenever activities are proposed adjacent to a habitat
conservation area with which state or federally endangered,
threatened, or sensitive species have a primary association, such
area shall be protected through the application of protection
measures in accordance with a critical area report prepared by a
qualified professional and approved by the City. Approval for
alteration of land adjacent to the habitat conservation area or its
buffer shall not occur prior to consultation with the Washington
Department of Fish and Wildlife for animal species, the Washington
State Department of Natural Resources for plant species, and other
appropriate federal or state agencies.
c.Bald eagle habitat shall be protected pursuant to the Washington
StateBald Eagle Protection Rules Section232-12-292WAC.
Whenever activities are proposed adjacent to a verified nest
territory or communal roost, a habitat management plan shall be
developed by a qualified professional. Activities are adjacent to
bald eagle sites when they are within 800feet or within one-half
mile (2,640feet) and in a shoreline foraging area. The Cityshall
verify the location of eagle management areas for each proposed
activity. Approval of the activity shall not occur prior to approval of
the habitat management plan by the Washington Department of
Fish and Wildlife.
2.Riparian habitat areas. Unless otherwise allowed in this chapter, all
structures and activities shall be located outside of the riparian
habitat area.
a.Establishment of riparian habitat areas. Riparian habitat areas shall
be established for habitats that include aquatic and terrestrial
ecosystems that mutually benefit each other and that are located
adjacent to rivers, perennial or intermittent streams, seeps, and
springs.
Environment - Page 48
b.A riparian habitat area width of 150feet is established along Yelm
Creek and Thompson Creek, both Type 5, intermittent streams
with low mass wasting potentialas defined in Section 222-16-031
WAC.
c.Increased riparian habitat area widths. The recommended riparian
habitat area widths shall be increased, as follows:
i.When the administrator determines that the recommended width
is insufficient to prevent habitat degradation and to protect the
structure and functions of the habitat area;
ii.When the frequently flooded area exceeds the recommended
riparian habitat area width, the riparian habitat area shall extend
to the outer edge of the frequently flooded area;
iii.When the habitat area is within an erosion or landslide hazard
area or buffer, the riparian habitat area width shall be the
recommended distance, or the erosion or landslide hazard area
or buffer, whichever is greater.
d.Riparian habitat area width averaging. The administrator may allow
the recommended riparian habitat area width to be reduced in
accordance with a critical area report only if:
i.The width reduction will not reduce stream or habitat functions,
including those of nonfish habitat;
ii.The width reduction will not degrade the habitat, including
habitat for anadromous fish;
iii.The proposal will provide additional habitat protection;
iv.The total area contained in the riparian habitat area of each
stream on the development proposal site is not decreased;
v.The recommended riparian habitat area width is not reduced by
more than25percent in any one location;
vi.The width reduction will not be located within another critical
area or associated buffer; and
vii.The reduced riparian habitat area width is supported by the best
available science.
e.Riparian habitat mitigation. Mitigation of adverse impacts to
riparian habitat areas shall result in equivalent functions and
values on a per function basis, be located as near the alteration as
feasible, and be located in the same subdrainage basin as the
habitat impacted.
f.Alternative mitigation for riparian habitat areas. The performance
Environment - Page 49
standards set forth in this subsection may be modified at the City's
discretion if the applicant demonstrates that greater habitat
functions, on a per function basis, can be obtained in the affected
subdrainage basin as a result of alternative mitigation measures.
4.Aquatic habitat. The following specific activities may be permitted
within a riparian habitat area, pond, lake, water of the state, and
marine habitat or associated buffer.
a.Clearingand grading. When clearing and grading is permitted as
part of an authorized activity or as otherwise allowed in these
standards, the following shall apply:
i.Grading is allowed only during the dry season, which is typically
regarded as beginning on May 1st and ending on October 1st of
each year; provided, that the Citymay extend or shorten the dry
season on a case-by-case basis, determined on actual weather
conditions.
ii.Filling or modification of a wetland or wetland buffer is permitted
only if it isconducted as part of an approved wetland alteration.
iii.The soil duff layer shall remain undisturbed to the maximum
extent possible. Where feasible, any soil disturbed shall be
redistributed to other areas of the project area.
iv.The moisture-holding capacity of the topsoil layer shall be
maintained by minimizing soil compaction or reestablishing
natural soil structure and infiltrative capacity on all areas of the
project area not covered by impervious surfaces.
v.Erosion and sediment control that meets or exceeds the
standards set forth in the [locally adopted stormwater
management regulations] shall be provided.
b.Shoreline erosion control measures. New, replacement, or
substantially improved shoreline erosion control measures may be
permitted in accordance with an approved critical area report that
demonstrates the following:
i.Natural shoreline processes will be maintained. The project will
not result in increased beach erosion or alterations to, or loss of,
shoreline substrate within one-quarter mile of the project area.
ii.The shoreline erosion control measures will not degrade fish or
wildlife habitat conservation areas or associated wetlands.
iii.Adequate mitigation measures ensure that there is no net loss of
the functions or values of intertidal habitat or riparian habitat as
a result of the proposed shoreline erosion control measures.
Environment - Page 50
iv.The proposed shoreline erosion control measures do not result in
alteration of intertidal migration corridors.
c.Streambank Stabilization. Streambank stabilization to protect new
structures from future channel migration is not permitted except
when such stabilization is achieved through bioengineering or soft
armoring techniques in accordance with an approved critical area
report.
d.Roads, trails, bridges, and rights-of-way. Construction of trails,
roadways, and minor road bridging, less than or equal to 30feet
wide, may be permitted in accordance with an approved critical
area report subject to the following standards:
i.There is no other feasible alternative route with less impact on
the environment;
ii.The crossing minimizes interruption of downstream movement of
wood and gravel;
iii.Roads in riparian habitat areas or their buffers shall not run
parallel to the water body;
iv.Trails shall be located on the outer edge of the riparian area or
buffer, except for limited viewing platforms and crossings;
v.Crossings, where necessary, shall only occur as near to
perpendicular with the water body as possible;
vi.Mitigation for impacts is provided pursuant to a mitigation plan
of an approved critical area report;
vii.Road bridges are designed according to the Washington
Department of Fish and Wildlife Fish Passage Design at Road
Culverts, 1999, and the National Marine Fisheries Service
Guidelines for Salmonid Passage at Stream Crossings, 2000;
and
viii.Trails and associated viewing platforms shall not be made of
continuous impervious materials.
e.Utility facilities. New utility lines and facilities may be permitted to
cross watercourses in accordance with an approved critical area
report if they comply with the following standards:
i.Fish and wildlife habitat areas shall be avoided to the maximum
extent possible;
ii.Installation shall be accomplished by boring beneath the scour
depth and hyporheic zoneof the water body and channel
migration zone, where feasible;
Environment - Page 51
iii.The utilities shall cross at an angle greater than 60degrees to
the centerline of the channel in streams or perpendicular to the
channel centerline whenever boring under the channel is not
feasible;
iv.Crossings shall be contained within the footprint of an existing
road or utility crossing where possible;
v.The utility route shall avoid paralleling the stream or following a
down-valley course near the channel; and
vi.The utility installation shall not increase or decrease the natural
rate of shore migration or channel migration.
f.Public flood protection measures. New public flood protection
measures and expansion of existing ones may be permitted,
subject to the City's review and approval of a critical area report
and the approval of a federal biological assessment by the federal
agency responsible for reviewing actions related to a federally
listed species.
g.Instream structures. Instream structures, such as, but not limited
to, high-flow bypasses, sediment ponds, instream ponds, retention
and detention facilities, tide gates, dams, and weirs, shall be
allowed only as part of an approved watershed basin restoration
project approved by the Cityand upon acquisition of any required
state or federal permits. The structure shall be designed to avoid
modifying flows and water quality in ways that may adversely
affect habitat conservation areas.
h.Stormwater conveyance facilities. Conveyance structures may be
permitted in accordance with an approved critical area report
subject to the following standards:
i.No other feasible alternatives with less impact exist;
ii.Mitigation for impacts is provided;
iii.Stormwater conveyancefacilities shall incorporate fish habitat
features; and
iv.Vegetation shall be maintained and, if necessary, added adjacent
to all open channels and ponds in order to retard erosion, filter
out sediments, and shade the water.
i.On-site sewage systems andwells.
i.New on-site sewage systems and individual wells may be
permitted in accordance with an approved critical area report
only if accessory to an approved residential structure, for which
it is not feasible to connect to a public sanitary sewer system.
Environment - Page 52
ii.Repairs to failing on-site sewage systems associated with an
existing structure shall be accomplished by utilizing one of the
following methods that result in the least impact:
1)Connection to an available public sanitary sewer system;
2)Replacement with a new on-site sewage system located in a
portion of the site that has already been disturbed by
development and is located landward as far as possible,
provided the proposed sewage system is in compliance with
local health regulations; or
3)Repair to the existing on-site septic system.
Environment - Page 53