HomeMy WebLinkAbout09/17/2025 - Agenda Packet
AGENDA
Planning Commission Meeting
6:00 PM - Wednesday, September 17, 2025
Council Chambers, 7th Floor, City Hall – 1055 S. Grady Way
1. CALL TO ORDER
2. ROLL CALL
3. CORRESPONDENCE RECEIVED
4. AUDIENCE COMMENT
1. Virtual Attendees
2. In-person Attendees
Those attending virtually (Call 253-215-8782, Zoom meeting ID: 880 3465 9736, password:
Weplan2024 or
https://us06web.zoom.us/j/88034659736?pwd=z1TyxJNsMEloal0MglAamlJkjbnLaR.1) will be
offered an opportunity to speak before the in-person (physical meeting at the City Hall, 7F
Council Chambers) comments are completed.
Please use your device to raise your (electronic) hand in order to be recognized by the
Recording Secretary.Each speaker will be provided three (3) minutes to address an item.
Groups or organizations may select a spokesperson to speak on a group’s behalf.
Alternatively, interested parties are encouraged to provide written comments to
planningcommission@rentonwa.gov.
Attendees will be muted and not audible to the Commission except during times they are
designated to speak.Public can use the “Raise Hand” option if attending through video.If there
are others calling in, you can be called upon by the last 4 digits of your telephone number.
Phone instructions: *6 to mute/unmute, *9 to raise hand.
5. COMMISSIONER COMMENTS
6. PUBLIC HEARING
a) Group 20A D-238: Comprehensive Plan Update - Transportation Element
b) Group 19B D-235: Critical Areas Ordinance Updates
7. COMMISSIONER COMMENTS
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8. ADJOURNMENT
Hearing assistance devices for use in the Council Chambers are available upon request.
For more information please visit rentonwa.gov/planningcommission
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CITY OF RENTON
Community and Economic Development Department
#D-235: Critical Areas Ordinance
Staff: Mariah Kerrihard, Associate Planner
Date: September 12, 2025
Applicant or Requestor: Staff
_____________________________________________________________________________________
SUPPLEMENTAL STAFF REPORT
SUMMARY: This Supplemental Staff Report provides responses to issues that were raised at a
Planning Commission meeting regarding amendments to the Renton Municipal Code Development
Regulations. It also includes additional information that staff has identified as being necessary to
include in the analysis for amendments.
GENERAL DESCRIPTION
The critical areas ordinance (CAO) is a set of development regulations that cities and counties
must adopt and enforce to protect specific environmentally sensitive areas and to safeguard the
public from natural hazards. The CAO is mandated by the state’s Growth Management Act (GMA).
The purpose of the proposed code amendment is to align the City’s regulations with current state
law and “best available science” (BAS) by the end of the year deadline.
BACKGROUND – CRITICAL AREA ORDINANCE
The Critical Areas Regulations are intended to guide development in ways that protect the
environment, public safety, and community well-being. Its goals include preserving natural
habitats, maintaining species diversity, and restoring critical areas where possible, while ensuring
activities in sensitive areas do not cause hazards, damage, or unnecessary costs to the public. It
supports state and city policies, helps officials make informed decisions on development
proposals, and works to minimize risks from issues like flooding and abandoned coal mines. In
doing so, it protects both property and the local tax base while also safeguarding riparian areas—
streams, rivers, and their banks—that provide essential benefits such as clean water, flood
storage, erosion control, and healthy ecosystems for fish and wildlife.
As part of the current update to the Critical Areas Ordinance, three main categories of changes are
being introduced: (1) code cleanup to clarify regulatory language and references, (2) new Channel
Migration Zone (CMZ) regulations and expanded mapping, and (3) updated requirements for
wetlands protection. Wetlands are one of the five types of critical areas identified in the GMA. The
GMA requires specific protections for wetlands because they provide a wide variety of essential
environmental benefits. Without protection or mitigation, even minor disturbances to wetlands can
reduce or eliminate these benefits. The Department of Ecology provides Wetland Guidance for
Critical Areas Ordinance (CAO) updates for Western and Eastern Washington. Their publication is
informed by their earlier best available science (BAS) document, Wetlands in Washington State –
Volume 1: A Synthesis of the Science (Sheldon et al., 2005) and stems from the guidance in
Wetlands in Washington State, Volume 2: Guidance for Protecting and Managing Wetlands
(Granger et al., 2005). The guidance is a concise and current representation of the many strategies
and approaches for managing wetlands found in those earlier volumes. The guidance is for local
jurisdictions working on designating and protecting wetlands as critical areas under the
Washington State Growth Management Act (GMA). Currently, the Channel Migration Zone (CMZ) is
within the Shoreline Management Program regulations. As part of the current update, the CMZ is
AGENDA ITEM #6. b)
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planned to be located in the CAO, which provides guidelines for how people can challenge the
boundaries of the CMZ, such as, bank stabilization along the Cedar River. The City is required to
adopt the updated regulations by the end of 2025.
THINGS TO CONSIDER: PLANNING COMMISSION QUESTIONS
Planning Commission Question:
What separates out the different categories for the wetlands?
Staff Response:
Cities in Washington State categorize their wetlands using the Washington State Wetland Rating
System, which assigns wetlands to one of four categories (I-IV) based on their functions, rarity,
sensitivity to disturbance, and the difficulty of replacing them if altered. This system is incorporated
into local municipal codes and critical area ordinances across the state.
Our proposed table would be utilizing both the overall categorization of the wetland as well as the
portion of it that specifically is associated with scoring the habitat. The current rating system in use
is based on manuals published by the Washington Department of Ecology—one each for western
and eastern Washington. Most cities have adopted the 2014 version or specify “as revised” (newest
version) in their codes. Wetlands are identified and delineated using the federal wetland
delineation manual and applicable regional supplements, with the rating system applied after
delineation to determine protection standards and required buffers. Category I wetlands get the
strictest protections, whereas Category IV wetlands may have reduced buffer requirements or be
eligible for more flexible mitigation.
Planning Commission Question:
Where would our wetlands in Renton fall in the wetland categories?
Staff Response:
Categories III and IV are commonly found wetlands in the City of Renton, yet we likely have all four
categories within the city. Category I and II wetlands are typically less common and represent rare,
higher-value ecological resources. Many of our higher functioning wetlands are city assets, and
many of our parks have higher functioning wetlands, such as the Black River Riparian Forest.
Planning Commission Question:
Can you provide a comparison of our existing and proposed wetland buffer widths?
Staff Response:
The table below sets forth required buffer distances for wetlands based on their category,
ecological characteristics, and the intensity of land use impacts nearby. The table aligns wetland
protection strategies by wetland category, habitat/water quality scores, and adjacent land use
intensity. The table groups wetlands into four types (I, II, III, IV), with Category I/II representing the
most sensitive category and Category IV representing the least sensitive category. In addition, the
table specifies attributes like conservation value, habitat score ranges, and water quality scores,
detailing ecological importance. Finally, the table divides land use impact into low, moderate, or
high, directly linking to buffer requirements.
AGENDA ITEM #6. b)
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The table below shows the changes in required buffer distances between wetlands and moderate
and high-impact land uses under new regulations. For each wetland category, habitat function and
the land use impacts (high, moderate, low) are applied within the table.
These updated buffer rules are designed to give greater protection to wetlands that perform vital
habitat functions, while adjusting or maintaining requirements where risks and functions are lower.
Habitat Function
Existing Requirement
(Low Impact / All
Other Land Uses)
Proposed
Requirement
(Low / Moderate
/ High Impact)
Difference
(Proposed -
Existing)
(Low / Moderate /
High)
I – Bogs & Heritage
Wetlands 175 ft / 200 ft 125 / 190 / 250 ft
–50 / –10 / +50 ft
(vs. Low / All Other
Uses)
I Habitat score 8–9 175 ft / 200 ft 150 / 225 / 300 ft –25 / +25 / +100 ft
I or II Habitat score 6–7 125 ft / 150 ft 75 / 110 / 150 ft –50 / –15 / 0 ft
I or II Habitat <6 & Water
Quality 8–9 75 ft / 115 ft 50 / 75 / 100 ft –25 / –40 / –15 ft
I or II Not meeting any above
characteristics 75 ft / 115 ft 50 / 75 / 100 ft –25 / –40 / –15 ft
II Habitat score 8–9 150 ft / 175 ft 150 / 225 / 300 ft 0 / +50 / +125 ft
III Habitat score 8–9 100 ft / 125 ft 150 / 225 / 300 ft +50 / +100 / +175 ft
III Habitat score 6–7 75 ft / 100 ft 75 / 110 / 150 ft 0 / +10 / +50 ft
AGENDA ITEM #6. b)
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III Habitat score 3–5 50 ft / 75 ft 40 / 60 / 80 ft –10 / –15 / +5 ft
IV Any habitat score 40 ft / 50 ft 25 / 40 / 50 ft –15 / –10 / 0 ft
PROPOSED CODE AMENDMENTS
The proposed revisions are based on the latest scientific data. While the details are still being
finalized, it is expected that the updates will include establishing regulations and authority within
the CAO to regulate the Channel Migration Zone, changes to wetland buffer widths, and
incorporating general code cleanup. Staff is proposing changes to the following code section:
• RMC 4-3-050 CRITICAL AREAS REGULATIONS
THINGS TO CONSIDER: PROPOSED CHANGES
Critical Areas Exemptions
• Routine maintenance, operation, and repair of existing parks, trails, roads, facilities, and
utilities, as well as construction of new trails, are listed as exempt activities in all critical
areas (Flood Hazard Areas, Geologic Hazard Areas, Habitat Conservation Areas, Streams
and Lakes, Wellhead Protection Areas, and Wetlands). For wetlands and buffers,
maintenance in areas of documented high-quality vegetation may trigger the need for buffer
enhancement or additional mitigation.
Wetlands
• Wetland buffer requirements have been revised to apply the best available science
consistent with Wetland Mitigation in Washington State, Part 1: Agency Policies and
Guidance, Version 2 (Ecology Publication No. 21-06-003, April 2021). Some wetland buffers
will become larger under the proposed amendments; a chart summarizing these proposed
buffer changes is provided below.
• Detailed tables for buffer widths and mitigation ratios are integrated for various wetland
categories and mitigation scenarios, aligned with state best practices. Administrative
buffer reductions and averaging have clear minimum reduction standards by critical area
type and strong criteria for when reductions are allowed, especially requiring functionally
equivalent or improved ecological outcomes.
• Introduction of "level of impact from proposed land use" system to determine the required
buffer widths for wetlands. This addition classifies land uses as high, moderate, or low
impact, and links them directly to regulatory buffers ensuring protection standards match
the potential environmental effects of adjacent development.
Channel Migration Zone
• The CMZ identifies river or stream corridors at risk for channel movement over time due to
erosion, flooding, or natural stream processes. The CMZ for the Cedar River is specifically
mapped by King County’s 2015 study and adopted into the city’s regulatory framework.
• The City or a property owner may request a site-specific reassessment of CMZ boundaries
using a geomorphic assessment. Updates are allowed if conditions have changed and must
be documented.
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