HomeMy WebLinkAboutPlanning 2018-11-08 ITEM 4 - STAFF REPORT - CRITICAL AREAS CODE UPDATETO:
City of Tukwila
Allan Ekberg, Mayor
INFORMATIONAL MEMORANDUM
Planning Commission
FROM: Minnie Dhaliwal, Planning Supervisor and Andrea Cummins, Urban
Environmentalist
DATE: October 29, 2018
SUBJECT: Update of TMC 18.45, Environmentally Sensitive Areas
ISSUE
Periodic update of the sensitive area regulations to reflect current best available science (BAS)
as required by the Growth Management Act.
BACKGROUND
All cities in Washington are required to adopt critical areas regulations by the Growth
Management Act (GMA) (RCW 36.70A.060). Critical areas, as identified in the GMA include
wetlands, frequently flooded areas, streams, geologically hazardous areas (steep slopes), and
fish and wildlife habitat conservation areas. In addition, cities are to give special consideration to
conservation or protection measures necessary to preserve or enhance anadromous fisheries.
Cities are required to include the best available science in developing policies and development
regulations to protect the functions and values of critical areas (RCW 36.70A.172). All
jurisdictions are required to review, evaluate, and, if necessary, revise their critical areas
ordinances according to an update schedule provided per RCW 36.70A.130. Tukwila's current
sensitive area regulations were adopted eight years ago in 2010. Per GMA the City must
periodically consider best available science (BAS) and update its sensitive areas ordinance. Any
deviations from BAS recommendations should be identified, assessed, and explained (WAC
365-195-915). Washington State Department of Ecology oversees sensitive area updates and
provides direction on BAS.
DISCUSSION
Elements of this update that have been completed:
• Comparison of existing code to BAS and development of a gap analysis to identify
inconsistences. The Gap Analysis report has been prepared by The Watershed Company
and is attached to this staff report.
• Outreach to affected property owners throughout the City included mailings, webpage
updates, stormwater bill insert, eHazelnut and an open house. A public information open
house was held on October 9, 2018 at the Tukwila Community Center. The notice of the
open house was mailed to all property owners, residents and businesses in the City.
Approximately 17 individuals attended the open house. A summary of comments received
at the open house or via email is included later in the staff report. Additionally, a website
page has been created where general members of the public can get a copy of the Gap
Analysis report and know about the status of the update. w.tukwilawa.gov/criticalareas.
An email group of interested parties is also being maintained. Any individual can get on
the interested parties list by emailing to criticalareas(a�tukwilawa.gov
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INFORMATIONAL MEMO
October 20.2018
Page
° Field work to categorize wetlands per the latest guidance from the Department of Ecology
has been done for known wetlands that exist north of 1-405. Staff is continuing to work to
categorize the remaining wetlands.
Anticipated key revisions include:
(*I
;W
Designation:
* Remove reference 0oState delineation manual and replace with language
from WAC 173-22-035, that states identification of wetlands and delineation
oftheir boundaries shall bedone inaccordance with the approved federal
wetland delineation manual and applicable regional supplements.
* Establish a period of validity for wetland delineations. Staff recommends five
year time limit on wetland reports/delineations. Generally, any delineation
done more than five years ago needs toborevisited oawetlands can change
significantly in ofive-year period due to changes in hydrology, land uses' and
plant species composition. Additionally, approved jurisdictional
determinations by the Corps expire after five years. Revisiting a wetland
delineation that iSfive Vrmore years old does not necessarily mean Gnew
wetland delineation needs to be done. It means it may be necessary to revisit
the site to determine whether the delineation is still accurate or needs to be
redone based Oncurrent conditions.
2- Rating:
R8f8[8OC8 latest version of State rating avateDl which is the Washington
State Wetland Rating System for Western N/a8hiro/un (Hruby 2014. Ecology
publication NO. 14-00-029). To avoid the need for future updates related to
rating system versions add language, "or aarevised and approved by
3- Buffer Widths:
The Watershed Company conducted 8Dupdated evaluation Ofthe Cih/Smapped
wetlands (north of 1-405) under the new recommended rating system. The
updated analysis confirmed that the majority 0fvv8t|8ndGvvithintheCitvdOhGvH
low habitat scores, and the remaining wetlands appear [Ohave moderate habitat
scores Ofsix O[seven. The 2O14rating system iSbased heavily OOthe habitat
score Of@particular wetland.
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INFORMATIONAL MEMO
October 29, 2018
Page 3
The Department of Ecology recommends the following buffers:
It should be noted that the buffer widths shown in the table below assume that the buffer is
vegetated with a native plant community and minimization measures listed in the second table
are implemented. If the buffer is unvegetated, sparsely vegetated, or vegetated with invasive
species, the buffer would need to be re -planted or the buffer width increased to provide
adequate buffer functions.
Category
Wetland
Wetland
buffer width (ft), Ecology 2014, high -intensity
land
use impact
buffer
width
(ft),
current
TMC
Habitat
score
<6
Habitat
Habitat
score
6-7
Habitat
score
6-7
Habitat
score 8-
9
Habitat score
8-9
score
<6
Standard
Buffer
Alternate
Buffer if
impact
minimization
measures
taken
Standard
Buffer
Alternate
Buffer if impact
minimization
measures
taken, plus 100
feet vegetated
corridor
between
wetland and
priority habitats
Standard
Buffer
Alternate Buffer
if impact
minimization
measures taken,
plus 100 feet
vegetated
corridor between
wetland and
priority habitats
100
100
75
150
110
300
225
II
100
100
75
150
110
300
225
III
80
80
60
150
110
300
225
IV
60
50
40
50
40
50
40
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INFORMATIONAL MEMO
October 20.2018
Page
Listed below are the impact minimization measures that may allow 25percent reduction from
the upper range of recommended buffers:
Disturbance
Required Measures to Minimize Impacts
Lights
*
Direct lights away from VVeL@Dd
yJoiaa
*
*
Locate activity that generates noise away from wetland
|fwarranted, enhance existing buffer with native vegetation
plantings adjacent Lonoise source
*
For activities that generate relatively continuous, potentially
disruptive noise, such ancertain heavy industry ormining,
establish anadditional 1U'heavily vegetated buffer strip
immediately adjacent to the outer wetland bUffgF
Toxic runoff
w
Route all new, untreated runoff away from wetland while
ensuring wetland iSnot devv8tered
*
Establish covenants limiting use Ofpesticides within 150feet
of wetland
*
Apply integrated pest management
8LorrnvvaLer runoff
*
Retrofit atornovvaterdetenUon and treatment for roads and
existing adjacent development
*
Prevent Ch8nne|ized flow from |8vvnS that directly enters the
buffer
*
Use Low Intensity Development (L|D)techniques where
appropriate (for more information refer LOthe drainage
ordinance and manual)
Change in water regime
*
Infiltrate or treat, dedain, and disperse into buffer new runoff
from impervious surfaces and new lawns
F'ato and
disturbance
human
p
Use privacy fencing C)Rplant dense vegetation tVdelineate
buffer edge and t0discourage disturbance using vegetation
appropriate for the 8C0r8giOn
*
Place wetland and its buffer in 8 separate tract Orprotect with
aconservation easement
Dust
p
Use best management practices 10control dust
Based on the field work done to categorize the wetlands north of|-405. majority of the wetlands
are Category U| vv8U8ndS. with 8 low habitat score Of3-5. Buffer quality 8tthe vast majority of
wetlands iSunhealthy (too narrow, dominated b«invasive species, Orsparsely V8gHt8|Hd]Initial
comparison of buffers required under the existing code and buffers recommended by the
Department OfEcology indicates that buffers will increase for some wetlands while 8few
wetlands may see reduction iDthe required buffer width. See Attachment E3for two sample
buffer change examples; one where the recommended buffer will increase and the second
where the buffer will decrease.
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INFORMATIONAL MEMO
October 29, 2018
Page 5
Policy Options for buffer widths:
Pros
Cons
Option 1
Adopt the standard buffer widths
recommended by the Department
of Ecology
The larger buffers
will provide better
buffer function given
majority of the
buffers are sparsely
vegetated; easier for
the developer as no
replanting or
monitoring required
Buffer widths will
significantly increase
which could limit
development potential;
quality of buffers will not
improve as no replanting
required.
Option 2
Adopt the standard buffer widths
recommended by the Department
of Ecology; but allow alternate
buffer if impact minimization
measures are taken
Provides options for
the developer
Quality of buffers will not
improve as no replanting
required
Option 3
Adopt the standard buffer widths
recommended by the Department
of Ecology; but allow alternate
buffer if impact minimization
measures are taken AND buffer is
replanted
Provides options for
the developer with
incentives for buffer
enhancement
Requires monitoring of
the replanted buffer for
at least five years
Staff recommends Option 3
4. Interrupted Buffer: The existing code does not address situations where the buffer is
interrupted by a road or other development. Staff is seeking direction from the Planning
Commission if administrative waiver process should be established for an interrupted
buffer. There are two policy questions to consider for addressing the interrupted buffer
situations:
a) Define what qualifies as interrupting the buffer. This could include a public or
private road; buildings; or parking lots. The criteria for waiver could include:
i) The existing legal improvement creates a substantial barrier to the buffer
function;
ii) The interrupted buffer does not provide additional protection of the critical
area from the proposed development; and
iii) The interrupted buffer does not provide significant hydrological, water quality
and wildlife buffer functions relating to the portion of the buffer adjacent to the
critical area.
b) Should additional water quality or other improvements be required to get the
waiver?
5. Buffer averaging instead of buffer reduction:
The existing code allows for reduction of the standard buffer width up to 50 percent
where existing conditions are degraded and where the applicant proposes to enhance
the degraded buffer. Rather than buffer reduction, Ecology guidance recommends buffer
averaging to provide flexibility to applicants and accommodate site constraints. To align
with BAS and per Ecology guidance averaging should be limited to require maintaining
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INFORMATIONAL MEMO
October 29, 2018
Page 6
at least 75 percent of the standard buffer width and should not reduce the total buffer
area.
6. Alterations:
The existing code provides an exemption for certain wetlands that are under 1,000
square feet. The exemption is from sequencing (showing that the impact cannot be
avoided or minimized). Mitigation of the impacts is still required per Ecology. Exempt
wetlands have to meet the following criteria:
a) habitat score under five;
b) are not associated with a riparian habitat or Shorelines of the State;
c) are not part of a wetland mosaic, and
d) do not contain priority habitat.
Per Ecology guidance, this exemption may be extended to isolated Category IV
wetlands under 4,000 square feet. Here are policy options for the Planning Commission
to consider:
Pros
Cons
Option 1
Keep the existing code
and exempt wetlands up
to 1000 sq. ft with
mitigation for wetland
impacts
These are exempt
under the existing
code. Code language
could be clarified that
wetland impacts still
need to be mitigated.
Some larger
wetlands that could
qualify for
exemption would
not qualify.
Option 2
Exempt wetlands up to
4000 sq. ft. with
mitigation for wetland
impacts
Increase the
exemption to the
highest allowed under
BAS. Wetland
impacts are mitigated
Mitigation is off site
or by fee in lieu.
Loss of wetlands in
Tukwila. Buffer
impacts are not
mitigated.
Option 3
Exempt wetlands up to
1000 sq. ft. with
mitigation for wetland
impacts; exempt
wetlands up to 4000 sq.
ft. with mitigation for
wetland and buffer
impacts
Increase the
exemption to the
highest allowed under
BAS. Two tiers of
mitigation: wetland
and buffer impacts
are mitigated for
wetlands larger than
1000; and only
wetland impacts
mitigated for wetlands
smaller than 1000 sq.
ft.
Mitigation is off site
or by fee in lieu.
Loss of wetlands in
Tukwila.
Staff recommends Option 1 as there are approximately 22 known Category IV wetlands
north of 1-405 that could be filled under Option 2 or 3.
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INFORMATIONAL MEMO
October 29, 2018
Page 7
7. Mitigation Standards: Clarify that mitigation ratio for buffer impacts should be 1:1
8. Wetland and buffer mitigation location:
The current code prefers off -site mitigation be located within city of Tukwila's
boundaries. However State and federal agencies advocate use of alternative
mitigation methods such as mitigation banks or in -lieu -fee programs. In order to
be consistent with regulations of these agencies city should consider allowing for
purchase of mitigation credit from an in -lieu fee program or bank, if that is the
best choice ecologically for a project.
t r"c r es
Rating:
Update ratings nomenclature to reflect Washington Department of Fish and Wildlife
ratings for simplicity. Type 1, 2, 3, 4 changed to S (Shoreline), F (Fish bearing), Np (Non -
fish bearing perennial), Ns (Non -fish bearing seasonal)
Stream Type
Watercourse Buffer (ft), TMC
Sample Buffer Ranges (ft)
S
Regulated under SMP
115-165
F
100
100-165
Np
80
50-65
Ns
50
50-65
No change is required in the buffers of S, F, Ns. The buffers of Np could be lowered from
80 feet to 50-65 range.
Policy options:
Pros
Cons
Option 1
Keep the existing
buffer of 80 feet for
Np streams
Given the existing
buffers are
degraded, larger
buffers are better
for ecological
functions
May limit
development
potential in a
developed urban
area.
Option 2
Lower the buffer to
50-65 range for Np
streams
Better development
potential
No buffer
enhancement and
small buffers not
good for
maintaining
ecological functions
Option 3
Keep the standard
buffer to 80 feet, but
allow an alternate
buffer in the range
of 50-65 with buffer
enhancement
Provides options to
the developer;
buffer enhancement
of degraded buffer
is achieved
Additional
monitoring
requirements to
achieve successful
buffer enhancement
Staff recommends Option 3
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INFORMATIONAL MEMO
October 29, 2018
Page 8
2. Buffer averaging vs reduction:
The existing code allows buffer reduction up to 50 percent with buffer enhancement.
However, as with wetland buffers, BAS-based buffers for watercourses are the minimum
widths necessary to protect watercourse functions when fully vegetated with native
vegetation. In addition, buffers narrower than 33 feet (i.e. a reduced buffer on a Type Ns
watercourse) are generally not considered functionally effective (The Watershed
Company 2011).
The City could continue to allow flexibility through buffer reduction with enhancement.
However, no more than a 25% reduction of the standard buffer widths should allowed to
ensure that reduced buffers are consistent with BAS and provide adequate protection.
Similar flexibility could be offered through buffer averaging.
Policy options:
Pros
Cons
Option 1
Allow up to 25
percent reduction in
the buffer, except in
Shoreline
jurisdiction. Require
buffer enhancement
in exchange.
Similar to current
approach.
Opportunity for
buffer
enhancement.
Option 2
Buffer averaging
The total area of the
Limited potential for
and allow up to 25
percent reduction in
buffer is preserved,
and flexibility
buffer averaging as
most areas are
the buffer in some
areas so that the
total area of the
buffer remains the
same.
provided to reduce
it in some areas in
exchange for larger
buffer in other
areas.
developed.
Staff recommends Option 2 as it is consistent with the approach for wetland buffer
deviations.
3. Interrupted buffer:
Similar to the discussion above under the wetlands section the regulations pertaining to
watercourses do not address situations where the buffer is interrupted by a road or other
development. Staff is seeking direction from the Planning Commission whether an
administrative waiver process should be established for an interrupted buffer for
watercourses. There are two policy questions to consider for addressing the interrupted
buffer situations:
a) Define what qualifies as interrupting the buffer. This could include a public or private
road; buildings; or parking lots. The criteria for waiver could include:
i) The existing legal improvement creates a substantial barrier to the buffer
function;
ii) The interrupted buffer does not provide additional protection of the critical area
from the proposed development; and
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INFORMATIONAL MEMO
October 20.2018
Page
iii) The interrupted buffer does not provide significanthvd[Ok]Okc@|'vv@Le[qu8]dv
and wildlife buffer functions relating to the portion of the buffer adjacent to the critical
area.
b) Should additional water quality or other improvements be required to get the
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a
This section of the code is administered by the Cit/a Public Works Department. Some of
the amendments that are being considered are:
IS
h
a
* Adding criteria that requires when peer -review of a geotechnical report for
adevelopment near steep slopes isrequired, particularly where o
geological hazard ursignificant slide potential has been identified.
* Creation ofodefault setback orbuffer width unareas ofsteep slopes. /\
peer -reviewed geOteChniC8|report may beused tOjustify the reduction Or
elimination of this buffer.
* Slope vegetation removal and guidelines onerosion control and best
management practices.
* Any other life safety issues that should beaddressed under this section.
41
4
4
A'
re
4
1. The city's list of fish and wildlife habitat conservation areas should be consistent with
GK8AdefinhUOn.
2. Define the process Ofdesignation Ofhabitats Oflocal importance.
3. The existing regulations establish a default buffer of 100 feet, it does not identify how an
applicant should determine whether a site -specific buffer width is necessary and what
that buffer width may be. Consistent with the Cib/'Sapproach for geologically hazardous
areas, buffers could bebased 0nsite-specific conditions; management
recommendations provided by the WDFW Priority Habitats and Species Program, if
applicable; and the recommendation Of8qualified professional iO@sensitive area
special study.
4. The uses and standards section should include a requirement for a habitat assessment
prepared byuqualified professional [obetter reflect BAS.
ri�_ojut-nt0VFN***1c-* Art -as
Frequently flooded areas iOthe City OfTukwila are regulated under TIVIC Ch@oter1G.52.
Flood Plain Management and nochanges are proposed aLthis time.
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INFORMATIONAL MEMO
October 29, 2018
Page 10
VI.
se
ee
Vesting:
Add language to clarify that only submittal of a complete building permit vests a project
to critical areas code. For instance, if a short plat is approved but homes are not
constructed and the code is updated any future development is subject to the new
updated code.
2. Expiration of decisions related to critical areas:
Establish a term limit of five years for any approvals to be consistent with time limits for
permits obtained from the state and federal agencies.
3. Permitted uses section:
See TMC 18.45.070 in Attachment C for the current list of uses permitted outright and
for uses permitted with administrative approval. This section needs to updated so that
standards such as dredging are not mixed in with uses.
4. Inclusion of tree retention, removal and replacement requirements:
Currently the tree retention, removal and replacement requirements are part of TMC
18.54, the Tree Code. Propose to place a section in the SAO that covers these subjects
so that Tree removal, retention and protection in sensitive areas is all in one place and
no cross -code reference is required.
Tree protection section will be very similar to that which exists in 18.54.070 as is
applicable to sensitive areas.
Non-invasive vegetation retention (except in cases of defective trees) in sensitive areas
is in current code. Only change that will be made is clarification that tree retention on
steep slopes is also required.
Tree Replacement section will be similar to that which is required in current shoreline
code (TMC 18.44.080).
5. Reorganization:
In order to improve the organization and make it easy to implement the code needs to
sequentially address 1. Mitigation sequencing; 2. What is allowed outright/what requires
Special Permission approval; 3. Criteria for approving deviations; 4. Mitigation
requirements; 5. Monitoring
6. Penalties for unauthorized alterations:
Establish penalties for illegal clearing in the wetland or buffer.
7. Non -conforming provisions:
TMC 18.70 Non -conforming Chapter governs what is allowed for any non -conforming
structures or uses. The regulations are more permissive for any residential non-
conforming structure in a sensitive area. However, there are no restrictions on
intensification of the use, which could be missed opportunity to get storm water quality
improvements or other buffer enhancements.
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INFORMATIONAL MEMO
October 29, 2018
Page 11
The policy options for the Planning Commission to consider are:
Pro
Con
Option 1
No changes to the
existing non-
conforming
provisions
Easy to administer
Missed
opportunities to get
some improvements
for the environment
Option 2
Establish new non-
conforming
thresholds for
development in the
critical area buffers
Provide some
incentives for
improving the
buffer and/or water
quality
8. Sensitive Areas Master Plan provisions:
The existing provisions for sensitive areas master plan (TMC18.45) allow creation of
higher quality wetlands in exchange for filling some small wetlands provided there is a
net environmental gain. However, there will be no incentive to creating wetlands with
better habitat value if it will result in larger buffers. Staff is seeking direction from the
Planning Commission if special exceptions should be established as incentives to
improve the habitat of wetlands provided this approach meets the current guidance from
Ecology.
9. Inventory update:
Add requirement for the applicant to provide surveyed data for maintenance of the City's
Critical Areas inventory map
PUBLIC OUTREACH: A public information open house was held on October 11, 2018 at the
Tukwila Community Center. The notice of the open house was mailed to all property owners,
residents and businesses in the City. Approximately 17 individuals attended the open house and
here is a summary of the comments:
• Question about interrupted buffers- do buffers apply across a road? What function
would they provide?
• Comment supporting adoption of state stream definitions and standards
• Comment supporting keeping the allowance for 50% buffer reduction on streams,
and in general keeping the existing regulations since people are now accustomed to
them.
• Comment supporting off -site mitigation options, particularly for streams or stream
buffers.
• Question about whether the State's water typing system accounts for degraded
water quality conditions.
• Comment expressing concern about bank stability risk from trees falling into and
remaining along the river.
• Comment that the City is not maintaining/enforcing the protection of shoreline buffer
functions on its own property, and yet it is putting the onus on private property
owners to maintain private shoreline buffers.
• Comment that a shade study is expensive, and it will not change the outcome when
the applicant is already planting to the maximum extent within the buffer.
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INFORMATIONAL MEMO
October 29, 2018
Page 12
RECOMMENDATION
Consider policy options identified above and identify any additional staff research needed. Staff
will then prepare an underline strike out of the code that addresses the gaps identified by the
review of best available science. A public hearing on the critical areas code update will be
scheduled in January 2019. The Planning Commission will then send a recommended draft to
the City Council for review and adoption.
ATTACHMENTS
A. Frequently asked questions
B. Sample wetland buffer change examples
C. Existing Tukwila Municipal Code Chapter 18.45 Environmentally Sensitive Areas
D. Gap Analysis report prepared by The Watershed Company
26