HomeMy WebLinkAboutCritical Areas Regulations - Streams & Lakes.docCritical Areas Regulations(City Code 4-3-050)
L. STREAMS AND LAKES:
1. Applicability/Lands to Which These Regulations Apply: These stream and lake regulations apply to sites containing all or portions of Class 2 to 4 streams or lakes and/or their buffers
as described below. This section does not apply to Class 1 waters which are regulated by RMC 4-3-090, Shoreline Master Program Regulations, or to Class 5 waters which are exempt. All
other critical area regulations, including, but not limited to, flood hazard regulations and wetland regulations, do apply to classified streams where applicable.
a. Classification System: The following classification system is hereby adopted for the purposes of regulating streams and lakes in the City. Stream and lake buffer widths are based
on the following rating system:
i. Class 1: Class 1 waters are perennial salmonid-bearing waters which are classified by the City and State as Shorelines of the State.
ii. Class 2: Class 2 waters are perennial or intermittent salmonid-bearing waters which meet one or more of the following criteria:
(a) Mapped on Figure Q4, Renton Water Class Map, as Class 2; and/or
(b) Historically and/or currently known to support salmonids, including resident trout, at any stage in the species lifecycle; and/or
(c) Is a water body (e.g., pond, lake) between one half (0.5) acre and twenty (20) acres in size.
iii. Class 3: Class 3 waters are non-salmonid-bearing perennial waters during years of normal rainfall, and/or mapped on Figure Q4, Renton Water Class Map, as Class 3.
iv. Class 4: Class 4 waters are non-salmonid-bearing intermittent waters during years of normal rainfall, and/or mapped on Figure Q4, Renton Water Class Map, as Class 4.
v. Class 5: Class 5 waters are non-regulated non-salmonid-bearing waters which meet one or more of the following criteria:
(a) Flow within an artificially constructed channel where no naturally defined channel had previously existed; and/or
(b) Are a surficially isolated water body less than one-half (0.5) acre (e.g., pond) not meeting the criteria for a wetland as defined in subsection M of this Section.
b. Measurement:
i. Stream/Lake Boundary: The boundary of a stream or lake shall be considered to be its ordinary high water mark (OHWM). The OHWM shall be flagged in the field by a qualified consultant
when any study is required pursuant to subsection L of this Section.
ii. Buffer: The boundary of a buffer shall extend beyond the boundaries of the stream or lake to the width applicable to the stream/lake class as noted in Subsection L5 of this Section,
Stream/Lake Buffer Width Requirements. Where streams enter or exit pipes, the buffer in this subsection L1b(ii) shall be measured perpendicular to the ordinary high water mark from
the end of the pipe along the open channel section of the stream.
Figure 4-3-050L1b(ii). Buffer measurement at pipe opening.
c. Maps and Inventory:
i. Mapped Streams and Lakes: The approximate location and extent of Class 2 to 4 water bodies within the City limits are indicated on a map in subsection Q of this Section, Maps. The
map is to be used as a guide to the general location and extent of streams. Specific locations and extents will be determined by the City based upon field review and applicant-funded
studies prepared pursuant to subsection L3 of this Section.
ii. Reclassification: Where there is a conflict between the Renton Water Class Map in Subsection Q and the criteria in subsection L1a of this Section, the criteria in subsection L1a
of this Section shall govern. The reclassification of a water body to a lower class (i.e. 2 to 3, or 3 to 4, etc.) requires administrator acceptance of a supplemental stream or lake
study, followed by a legislative amendment to the map in subsection Q of this Section prior to its effect.
iii. Unmapped Streams and Lakes: Streams and lakes which are defined in subsection L1a of this Section, Classification System, but not shown on the Renton Water Class Map in subsection
Q of this
Section, are presumed to exist in the City and are regulated by all the provisions of this Section. If the water body is unmapped according to the City of Renton’s Water Class Map (refer
to subsection Q of this Section), and:
(a) The width of the stream channel averages less than two feet (2) at the ordinary high water mark; or
(b) The stream channel has an average gradient of greater than twenty percent (20%); or
(c) The channel or water body is upstream of an existing, enduring, and complete barrier to salmonid migration, as interpreted in subsection L1c(iv) of this Section, or as shown on the
City of Renton’s Salmonid Migration Barrier Map, and the channel or water body contains water only intermittently upstream of the barrier during years of normal rainfall; or
(d) The water body is isolated from any connected stream and/or wetland; or
(e) The water body is less than one-half (0.5) acre in size and connected to a stream meeting the criteria noted in subsections L1c(iii)(a) through (c) of this Section;
Then the water body is considered non-salmonid-bearing and water class would be assessed based upon the non-salmonid-bearing waters criteria in subsections L1a(iii) through (v) of this
section. However, If none of the conditions above apply, then the water body is considered Salmonid-Bearing – Class 2. Classification of an unmapped stream or lake is effective upon
expiration of the fourteen (14) day appeal period following the Administrator’s determination, and the map in subsection Q of this Section shall be amended consistent with Administrator
determinations at the next appropriate amendment cycle.
iv. Salmonid Migration Barriers: For purposes of classifying or reclassifying water bodies, features determined by the Administrator to be salmonid migration barriers per definition
in RMC 4-11-190 shall be mapped. The Administrator shall prepare and update the map as appropriate and maintain a copy in the Planning/Building/Public Works Customer Service Area.
v. Experts or State Agency May Be Required or Consulted: The City may require an applicant to retain an expert or to consult the Washington Department of Fish and Wildlife to assess
salmonid-bearing status of the channel in question and prepare a report to the City detailing the facts and conclusion of their analysis.
vi. Criteria to Govern: The actual presence or absence of the stream and lake criteria listed in this subsection L, as determined by qualified professionals, shall govern the treatment
of an individual
building site or parcel of land requiring compliance with these regulations.
2. Applicability – Activities to Which This Section Applies: This Section applies to all non-exempt activities on sites containing Class 2 to 4 streams or lakes and their associated
buffers.
3. Studies Required:
a. When Standard Stream or Lake Study Is Required: The applicant shall be required to conduct a standard stream or lake study per RMC 4-8-120 if a site contains a water body or buffer
area or the project area is within one hundred feet (100) of a water body even if the water body is not located on the subject property.
b. When Supplemental Stream or Lake Study is Required: The applicant shall be required to conduct a supplemental stream or lake study per RMC 4-8-120 if a site contains a water body
or buffer area and changes to buffer requirements or alterations of the water body or its associated buffer are proposed, either administratively or via a variance request.
c. When Stream or Lake Mitigation Plan is Required: The applicant shall be required to conduct a stream or lake mitigation plan per RMC 4-8-120 if impacts are identified within a supplemental
stream or lake study. The approval of the stream or lake mitigation plan by the Administrator shall be based on the criteria located in subsection L3c(ii) of this Section.
i. Timing of Mitigation Plan – Final Submittal and Commencement: When a stream or lake mitigation plan is required, the applicant shall submit a final mitigation plan for the approval
of the Administrator prior to the issuance of building or construction permits, whichever comes first. The applicant shall receive written approval of the final mitigation plan prior
to commencement of any mitigation activity.
ii. Criteria for Approval of Stream or Lake Mitigation Plan for Alterations of Streams and Lakes or Associated Buffers: In order to approve a stream or lake mitigation plan the Administrator
shall find that the plan demonstrates compliance with the following criteria:
(a) Mitigation Location: Mitigation location shall follow the preferences in subsections L3c(ii)(a)(1) to (4) of this Section. Basins and subbasins are indicated in subsection Q of this
Section, Maps:
(1) On-Site Mitigation: On-site mitigation is required unless the Reviewing Official finds that on-site mitigation is not feasible or desirable;
(2) Off-Site Mitigation within Same Drainage Subbasin as Subject Site: Off-site mitigation may be allowed when located within the same drainage subbasin as the subject site and if it
achieves equal or improved ecological functions over mitigation on the subject site;
(3) Off-Site Mitigation within Same Drainage Basin within City Limits: Off-site mitigation may be allowed when located within the same drainage basin within the Renton City limits if
it achieves equal or improved ecological functions within the City over mitigation within the same drainage subbasin as the project;
(4) Off-Site Mitigation within the Same Drainage Basin Outside the City Limits: Off-site mitigation may be allowed when located within the same drainage basin outside the Renton City
limits if it achieves equal or improved ecological functions over mitigation within the same drainage basin within the Renton City limits and it meets City goals.
(b) Mitigation Type: Types of mitigation shall follow the preferences in subsections L3c(ii)(b)(1) to (4) of this Section:
(1) Daylighting (returning to open channel) of streams or removal of manmade salmonid migration barriers;
(2) Removal of impervious surfaces in buffer areas and improved biological function of the buffer;
(3) In-stream or in-lake mitigation as part of an approved watershed basin restoration project;
(4) Other mitigation suitable for site and water body conditions that meet all other provisions for a mitigation plan.
In all cases, mitigation shall provide for equivalent or greater biological functions per subsection L3c(ii)(e) of this Section.
(c) Contiguous Corridors: Mitigation sites shall be located to preserve or achieve contiguous riparian or wildlife corridors 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; and
(d) Non-Indigenous Species: Wildlife or fish species not indigenous to the region shall not be introduced into a riparian mitigation area unless authorized by a State or Federal permit
or approval. Plantings shall be consistent with subsection L6c of this Section; and
(e) Equivalent or Greater Biological Functions: The Administrator shall utilize the report “City of Renton Best Available Science Literature Review and Stream Buffer Recommendations”
by AC Kindig & Company and Cedarock Consultants, dated February 27, 2003, unless superseded with a City-adopted study, to determine the existing or potential ecological function of
the stream or lake or riparian habitat that is being affected. Mitigation shall address each function affected by
the alteration. Mitigation to compensate alterations to stream/lake areas and associated buffers shall achieve equivalent or greater biologic and hydrologic functions and shall include
mitigation for adverse impacts upstream or downstream of the development proposal site. No net loss of riparian habitat or water body function shall be demonstrated; and
(f) Minimum Mitigation Plan Performance Standards: See Subsection F8 of this Section.
(g) Additional Conditions of Approval: The Administrator shall condition approvals of activities allowed within or abutting a stream/lake or its buffers, as necessary to minimize or
mitigate any potential adverse impacts. Conditions may include, but are not limited to, the following:
(1) Preservation of critically important vegetation and/or habitat features such as snags and downed wood;
(2) Limitation of access to the habitat area, including fencing to deter unauthorized access;
(3) Seasonal restriction of construction activities; and
(4) Establishment of a duration and timetable for periodic review of mitigation activities.
(h) Based on Best Available Science: The applicant shall demonstrate that the mitigation is based on consideration of the best available science as described in WAC 365-195-905; or where
there is an absence of valid scientific information, the steps in RMC 4-9-250F are followed.
iii. Performance Surety: The Administrator shall require a performance surety to ensure completion and success of proposed mitigation, per subsection G of this Section and RMC 4-1-230.
iv. Alternative Mitigation: The mitigation requirements set forth in this subsection L3 may be modified at the Administrator’s discretion if the applicant demonstrates that improved
habitat functions, on a per function basis, can be obtained in the affected sub-drainage basin as a result of alternative mitigation measures.
d. Studies Waived:
i. Standard Stream or Lake Study: May only be waived by the Administrator when the applicant provides satisfactory evidence that:
(a) A road, building or other barrier exists between the water body and the proposed activity, or
(b) The water body or required buffer area does not intrude on the applicant’s lot, and based on evidence submitted, the
proposal will not result in significant adverse impacts to nearby water bodies regulated under this Section; or
(c) Applicable data and analysis appropriate to the proposed project exists and an additional study is not necessary.
ii. Supplemental Stream or Lake Study: May only be waived by the Administrator when:
(a) No alterations or changes to the stream or lake, or its standard buffer are proposed; or
(b) Applicable data and analysis appropriate to the proposed project exists and an additional report is not necessary.
iii. Stream or Lake Mitigation Plan: May only be waived when no impacts have been identified through a supplemental stream or lake study.
e. Period of Validity for Studies Associated with This Section: Studies submitted and reviewed are valid for five (5) years from date of study completion unless the Administrator determines
that conditions have changed significantly.
4. General Standards for Class 2 to 4 Waters:
a. Disturbance Prohibited: Streams and lakes and their buffer areas shall be undisturbed, except where the buffer is to be enhanced, or where exemptions allowed in subsection C of this
Section are conducted, or where allowed to be altered in accordance with subsections L5, L7 and L8 of this Section. Where water body or buffer disturbance has occurred in accordance
with exemption or development permit approval during construction or other activities, revegetation with native vegetation shall be required.
b. No Net Loss: There shall be no net loss of riparian area or shoreline ecological function resulting from any activity or land use occurring within the regulated buffer area.
5. Stream/Lake Buffer Width Requirements:
a. Buffers and Setbacks:
i. Minimum Stream/Lake Buffer Widths: The minimum width of the required buffers shall be based upon the water body class.
(a) Class 2: one hundred feet (100).
(b) Class 3: seventy five feet (75).
(c) Class 4: thirty five feet (35).
ii. Piped or Culverted Streams:
(a) Building structures over a natural stream located in an underground pipe or culvert except as may be granted by a variance in RMC 4-9-250 is prohibited. Transportation or utility
crossings or other alterations pursuant to subsection L8 of this Section are allowed. Pavement over a pre-existing piped stream is allowed. Relocation of the piped stream system around
structures is allowed. If structure locations are proposed to be changed or the piped stream is being relocated around buildings, a hydrologic and hydraulic analysis of existing piped
stream systems will be required for any development project site that contains a piped stream to ensure it is sized to convey the one hundred (100) year runoff level from the total
upstream tributary area based on future land use conditions.
(b) No buffers are required along segments of piped or culverted streams. The City shall require easements and setbacks from pipes or culverts consistent with stormwater requirements
in RMC 4-6-030 and the adopted drainage manual.
b. Increased Buffer Width:
i. Areas of High Blow-down Potential: Where the stream/lake buffer is in an area of high blow-down potential as identified by a qualified professional, the buffer width may be expanded
an additional fifty feet (50) on the windward side by the Responsible Official. Notifications may be required per subsection F8 of this Section.
ii. Buffers Falling Within Protected Slope or Very High Landslide Area: When the required stream/lake buffer falls within a protected slope or very high landslide hazard area or buffer,
the stream/lake buffer width shall extend to the boundary of the protected slope or the very high landslide hazard buffer. Notifications may be required per subsection F8 of this Section.
c. Reduction of Buffer Width:
i. Authority: Based upon an applicant’s request, and the acceptance of a supplemental stream or lake study, the Administrator may approve a reduction in the minimum buffer widths where
the applicant can demonstrate compliance with subsections L5c(iv)(a), (c), (d), (e) and (f) of this Section and any mitigation requirements as a result of subsection L3c(ii) of this
Section; or compliance with subsections L5c(iv)(b), (c), (d), (e), and (f) of this Section and any mitigation requirements as a result of subsection L3c(ii) of this Section.
ii. Minimum Buffer Width Permissible by Administrator: An enhanced buffer shall not be less than the widths specified below for reduced buffers.
(a) Class 2: seventy five feet (75).
(b) Class 3: fifty feet (50).
(c) Class 4: twenty five feet (25).
(d) Sites Separated from Stream or Lake: As determined by the Administrator, for development proposed on sites separated from the stream or lake by pre-existing, intervening, and lawfully
created structures, roads, bulkheads/hard structural stabilization, or other substantial existing improvements. For the purposes of this Section, the intervening lots/parcels, roads,
bulkheads/hard structural stabilization, or other substantial improvements shall be found to:
(1) Separate the subject upland property from the water body due to their height or width; and
(2) Substantially prevent or impair delivery of most riparian functions from the subject upland property to the water body.
The buffer width established shall reflect the riparian functions that can be delivered to the regulated stream.
Greater buffer width reductions than listed in subsections L5c(ii)(a) through (c) of this Section require review as a variance per subsection N3 of this Section and RMC 4-9-250B. Where
a Class 2 or 3 stream is daylighted, greater buffer reductions may be allowed by modification in subsection N2 of this Section.
iii. Procedure: Such determination and evidence shall be included in the application file. Public notification shall be given as follows:
(a) For applications that are not subject to notices of application per chapter 4-8 RMC, notice of the buffer determination shall be given by posting the site and notifying parties of
record, if any, in accordance with chapter 4-8 RMC.
(b) For applications that are subject to notices of application, the buffer determination or request for determination shall be included with notice of application. Upon determination,
notification of parties of record, if any, shall be made.
iv. Criteria for Approval of Reduced Buffer Width: The following criteria in subsections L5c(iv)(a) and (c) through (f), or criteria (iv)(b) through (f) of this Section shall be met:
(a) Buffer Condition: Either subsection (1) and (3) through (5) shall be met or subsection (2) through (5) shall be met:
(1) The buffer area land is extensively vegetated with native species, including trees and shrubs, and has less than five percent (5%) non-native invasive species cover, and has less
than fifteen percent (15%) slopes; or
(2) The buffer can be enhanced with native vegetation and removal of non-native species per criteria in subsection
L5c(iv)(c) of this Section, and has less than fifteen percent (15%) slopes; and
(3) The width reduction will not reduce stream or lake functions, including those of anadromous fish or nonfish habitat; and
(4) The width reduction will not degrade riparian habitat; and
(5) No direct or indirect, short-term or long-term, adverse impacts to regulated water bodies, as determined by the City, will result from a regulated activity. The City’s determination
shall be based on specific site studies by recognized experts, pursuant to subsection F3 of this section and RMC 4-8-120; or
(b) The proposal includes daylighting of a stream, or removal of legally installed, as determined by the Administrator, salmonid passage barriers; and
(c) The project includes a buffer enhancement plan using native vegetation and substantiates that the enhanced area will be equal to or improve the functional attributes of the buffer;
or in the case of existing developed sites where a natural buffer is not possible, the proposal includes on- or off-site riparian/lakeshore or aquatic enhancement proportionate to its
project specific or cumulative impact on shoreline ecological functions; and
(d) The proposal will result in, at minimum, no net loss of stream/lake/riparian ecological function; and
(e) The proposal does not result in increased flood hazard risk; and
(f) The proposed buffer standard is based on consideration of the best available science as described in WAC 365-195-905; or where there is an absence of valid scientific information,
the steps in RMC 4-9-250F are followed.
d. Averaging of Buffer Width:
i. Authority: Based upon an applicant’s request, and the acceptance of a supplemental stream or lake study, the Administrator may approve buffer width averaging.
ii. Minimum Averaged Buffer Widths: In no instance shall the buffer width be less than:
(a) Class 2: fifty feet (50).
(b) Class 3: thirty seven and one-half feet (37.5).
(c) Class 4: twenty five feet (25).
Greater buffer width reductions than listed in subsections L5(d)(iii)(a) through (c) of this Section require review as a variance per subsection N3 of this Section and RMC 4-9-250B.
iii. Criteria for Approval: Buffer width averaging may be allowed by the Administrator only where the applicant demonstrates all of the following:
(a) The water body and associated riparian area contains variations in ecological sensitivity or there are existing physical improvements in or near the water body and associated riparian
area; and
(b) Buffer width averaging will result in no net loss of stream/lake/riparian ecological function; and
(c) The total area contained within the buffer after averaging is no less than that contained within the required standard buffer width prior to averaging; and
(d) The proposed buffer standard is based on consideration of the best available science as described in WAC 365-195-905; or where there is an absence of valid scientific information,
the steps in RMC 4-9-250F are followed.
iv. Buffer Enhancement May be Required: Where the buffer width is reduced by averaging per this subsection, buffer enhancement shall be required where appropriate to site conditions,
habitat sensitivity, and proposed land development characteristics.
v. Notification: Notification may be required consistent with subsection F8 of this Section.
6. Stream or Lake Buffer Use Restrictions and Maintenance: Any activity or proposal subject to this subsection L shall comply with the following standards within required buffer areas:
a. Preservation of Native Vegetation: Existing native vegetation shall be preserved to the extent possible, preferably in consolidated areas.
b. Revegetation Required: Where water body buffer disturbance has occurred in accordance with exemption or development permit approval or other activities, revegetation with native vegetation
shall be required.
c. Use of Native Species: When revegetation is required, native species, or other appropriate species naturalized to the Puget Sound region and approved by the Reviewing Official, shall
be used. A variety of species shall be used which serve as food or shelter from climatic extremes and predators, and as structure and cover for reproduction and rearing of young.
d. Removal of Noxious Species: When required as a condition of approval, noxious or undesirable species of plants shall be removed or controlled so as to not compete with native vegetation.
e. Impervious Surface Restrictions: Where impervious surfaces exist in buffer areas, such impervious surfaces shall not be increased or expanded within the buffer area. The extent of
impervious surfaces within the buffer area may only be rearranged if the reconfiguration of impervious surfaces and restoration of prior surfaced areas is part of an enhancement proposal
that improves ecological function of the area protected by the buffer.
7. Criteria for Permit Approval – Class 2 to 4: Permit approval by the Reviewing Official for projects on or near regulated water bodies shall be granted only if the approval is consistent
with the provisions of this subsection L, and complies with the following:
a. Creation of Native Growth Protection Areas Required: As a condition of any approval for any development permit issued pursuant to this Section, the property owner shall be required
to create a native growth protection area containing the stream/lake area and associated buffers based upon field investigations performed pursuant to subsection E4 of this Section;
and
b. At least one of the following conditions must apply:
i. A proposed action meets the standard provisions of this Section and results in no net loss of regulated riparian area or shoreline ecological function in the drainage basin where
the site is located; or
ii. A proposed action meets alternative administrative standards pursuant to this Section and the proposed activity results in no net loss of regulated riparian area or shoreline ecological
function in the drainage basin where the site is located; or
iii. A variance process is successfully completed and the proposed activity results in no net loss of regulated riparian area or shoreline ecological function in the drainage basin where
the site is located.
8. Alterations Within Streams and Lakes or Associated Buffers.
a. Transportation Crossings:
i. Criteria for Administrative Approval of Transportation Crossings in Stream/Lake or Buffer Areas: Construction of vehicular or non-vehicular transportation crossings may be permitted
in accordance with an approved supplemental stream/lake study subject to the following criteria:
(a) The proposed route is determined to have the least impact on the environment, while meeting City Comprehensive Plan Transportation Element requirements and standards in RMC 4-6-060;
and
(b) The crossing minimizes interruption of downstream movement of wood and gravel; and
(c) Transportation facilities in buffer areas shall not run parallel to the water body; and
(d) Crossings occur as near to perpendicular with the water body as possible; and
(e) Crossings 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, as may be updated, or equivalent manuals as determined by the Responsible Official; and
(f) Seasonal work windows are determined and made a condition of approval; and
(g) Mitigation criteria of subsection L3c(ii) of this Section are met.
b. Alterations of Streams and Lakes or Associated Buffers – Utilities:
i. Criteria for Administrative Approval of Utilities in Stream/Lake or Buffer: New utility lines and facilities may be permitted to cross water bodies in accordance with an approved
supplemental stream/lake study, if they comply with the following criteria:
(a) Fish and wildlife habitat areas shall be avoided to the maximum extent possible; and
(b) The utility is designed consistent with one or more of the following methods:
(1) Installation shall be accomplished by boring beneath the scour depth and hyporheic zone of the water body and channel migration zone; or
(2) The utilities shall cross at an angle greater than sixty (60) degrees to the centerline of the channel in streams or perpendicular to the channel centerline; or
(3) Crossings shall be contained within the footprint of an existing road or utility crossing; and
(c) New utility routes shall avoid paralleling the stream or following a down-valley course near the channel; and
(d) The utility installation shall not increase or decrease the natural rate of shore migration or channel migration; and
(e) Seasonal work windows are determined and made a condition of approval; and
(f) Mitigation criteria of subsection L3c(ii) of this Section are met.
c. Alterations of Streams and Lakes or Associated Buffers – In-Water Structures and In-Water Work:
i. Administrative Approval of In-Water Structures or In-Water Work: In accordance with an approved supplemental stream or lake study, in-water structures or work may be permitted, subject
to the following: In-stream structures, such as, but not limited to, high flow bypasses, sediment ponds, in-stream ponds, retention and detention facilities, tide gates, dams, and weirs,
shall be allowed as part of an approved watershed basin restoration project approved by the City of Renton, and in accordance with mitigation criteria of subsection L3c(ii) of this
Section. The applicant will obtain and comply with State or Federal permits and requirements.
d. Alterations of Streams and Lakes or Associated Buffers – Dredging.
i. Administrative Approval of Dredging: Dredging may be permitted only when:
(a) Dredging is necessary for flood hazard reduction purposes, if a definite flood hazard would exist unless dredging were permitted; or
(b) Dredging is necessary to correct problems of material distribution and water quality, when such problems are adversely affecting aquatic life; or
(c) Dredging is associated with a stream habitat enhancement or creation project not otherwise exempt in subsection C of this Section; or
(d) Dredging is necessary to protect public facilities; or
(e) Dredging is required as a maintenance and operation condition of a federally funded flood hazard reduction project or a hazard mitigation project; and
(f) Applicable mitigation criteria of subsection L3c(ii) of this Section are met.
e. Alterations of Streams and Lakes or Associated Buffers – Stream Relocation:
i. Administrative Approval of Stream Relocation: Stream relocation may be allowed when analyzed in an accepted supplemental stream or lake assessment, and when the following criteria
and conditions are met:
(a) Criteria: Stream relocation may only be permitted if associated with:
(1) A public flood hazard reduction/habitat enhancement project approved by appropriate State and/or Federal agencies; or
(2) Expansion of public road or other public facility improvements where no feasible alternative exists; or
(3) A public or private proposal restoring a water body and resulting in a net benefit to on- or off-site habitat and species.
(b) Additional Conditions: The following conditions also apply to any stream relocation proposal meeting one or more of the above criteria:
(1) Buffer widths shall be based upon the new stream location; provided, that the buffer widths may be reduced or averaged if meeting criteria of subsection L5c or L5d of this Section
or subsection L8e(i)(b)(2) of this Section. Where minimum required buffer widths are not feasible for stream relocation proposals that are the result of activities pursuant to criteria
in subsections L8e(i)(a)(1) and (2) of this Section, other equivalent on- or off-site compensation to achieve no-net-loss of riparian function is provided;
(2) When Class 4 streams are proposed for relocation due to expansions of public roads or other public facility improvements per subsection L8e(i)(a)(2) of this Section, the buffer area
between the facility and the relocated stream shall not be less than the width prior to the relocation. The provided buffer between the facility and the relocated stream shall be enhanced
or improved to provide appropriate function given the class and condition of the stream; or if there is no buffer currently, other equivalent on- or off-site compensation to achieve
no net loss of riparian function is provided.
(3) Applicable mitigation criteria of subsection L3c(ii) of this Section must be met.
(4) Proper notifications and records must be made of stream relocations, per subsection D3b of this Section, Information to be Obtained and Maintained, and subsection D3c of this Section,
Alterations of Watercourses, in cases where the stream/lake is subject to flood hazard regulations of this Section, as well as subsection F8 of this Section if neighboring properties
are impacted.
f. Alterations – Single Family Home – Existing Legal Lot: If criteria to reduce or average a buffer cannot be met, construction, reconstruction, additions, and associated accessory structures
of a single family home on an existing legal lot may be allowed to intrude into a buffer pursuant to a variance as stated in RMC 4-9-250B1.
g. Alterations – Other: Proposed alterations of a stream or lake or associated buffer not addressed by subsections L8a to L8f of this Section require a variance pursuant to RMC 4-9-250B
in order to be conducted.
h. When Variance Is Required: If the proposed alteration applicable to Subsections L8a to L8g of this Section does not meet the above criteria, it shall require a variance per subsection
N3 of this Section and RMC 4-9-250B in order to be conducted.
9. Incentives for Restoration of Streams Located in an Underground Pipe or Culvert: Daylighting of culverted watercourses should be encouraged and allowed with the following incentives:
a. Modified Standards:
i. Residential Zones: Setbacks, lot width and lot depth standards of chapter 4-2 RMC may be reduced by the Reviewing Official without requirement of a variance for lots that abut the
daylighted watercourse to accommodate the same number of lots as if the watercourse were not daylighted.
ii. Mixed Use, Commercial, and Industrial Zones:
(a) Where greater lot coverage allowances are provided for structured parking in chapter 4-2 RMC, lot coverage may be increased to the limit allowed for structured parking if instead
a stream is daylighted. The increase in impervious surface allowed shall be equal to the area of stream restoration.
(b) Density bonuses may be allowed pursuant to RMC 4-9-065 where specified.
b. Standard buffers may be reduced per subsection L5c of this Section. If reduced buffers in subsection L5c of this Section along with other development standards of the zone would not
allow the same development level as without the watercourse daylighting, a modification may be requested as in subsection N of this Section.
c. When designed consistent with the City’s flood regulations in subsection I6 of this Section, portions of the daylighted stream/created buffer may be considered part of compensatory
storage in flood hazard areas.
d. Stream relocation is permitted subject to subsection L8 of this Section. (Ord. 5137, 4-25-2005)