HomeMy WebLinkAboutDeclaration of Covenant - Drainage Facilities and On-Site BMPsPage 1 of ___
Return Address:
City Clerk’s Office
City of Renton
1055 S Grady Way
Renton, WA 98057
DECLARATION OF COVENANT
FOR INSPECTION AND MAINTENANCE OF DRAINAGE FACILITIES AND
ON-SITE BMPS
Grantor:
Grantee: City of Renton, a Washington municipal corporation
Legal Description:
Assessor's Tax Parcel ID#:
IN CONSIDERATION of the approved City of Renton (check one of the following)
Residential Building Permit Commercial Building Permit
Clearing and Grading Permit Civil Construction or Utility Permit
for Permit(s)_____________________ (Construction/Building/Utility Permit #) relating to the real property
("Property") described above, the Grantor(s), the owner(s) in fee of that Property, hereby
covenants (covenant) with the City of Renton (“City of Renton” or “City”), a municipal corporation
of the state of Washington, that he/she (they) will observe, consent to, and abide by the conditions
and obligations set forth and described in Paragraphs 1 through 9 below with regard to the
Property, and hereby grants (grant) an easement as described in Paragraphs 2 and 3. Grantor(s)
hereby grants (grant), covenants (covenant), and agrees (agree) as follows:
1.The Grantor(s) or his/her (their) successors in interest and assigns ("Owners ") shall at their own
cost, operate, maintain, and keep in good repair, the Property's drainage facilities constructed
as required in the approved construction plans and specifications __________________ (Project
Plan #) on file with the City of Renton and submitted to the City of Renton for the review and
approval of permit(s) _____________________________ (Construction/Building/Utility Permit #). The
Property's drainage facilities are shown and/or listed on Exhibit A – Site Plan. The Property’s
drainage facilities shall be maintained in compliance with the operation and maintenance
schedule included and attached herein as Exhibit B – Operations and Maintenance. Drainage
facilities include pipes, channels, flow control facilities, water quality facilities, on-site best
management practices (BMPs) and other engineered structures designed to manage and/or
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treat stormwater on the Property. On-site BMPs include dispersion and infiltration devices,
bioretention, permeable pavements, rainwater harvesting systems, tree retention credit,
reduced impervious surface footprint, vegetated roofs and other measures designed to mimic
pre-developed hydrology and minimize stormwater runoff on the Property.
2.City of Renton shall have the right to ingress and egress over those portions of the Property
necessary to perform inspections of the stormwater facilities and BMPs and conduct
maintenance activities specified in this Declaration of Covenant and in accordance with the
Renton Municipal Code. City of Renton shall provide at least thirty (30) days’ written notice to
the Owners that entry on the Property is planned for the inspection of drainage facilities. After
the thirty (30) days, the Owners shall allow the City of Renton to enter for the sole purpose of
inspecting drainage facilities. In lieu of inspection by the City, the Owners may elect to engage
a licensed civil engineer registered in the state of Washington who has expertise in drainage to
inspect the drainage facilities and provide a written report describing their condition. If the
engineer option is chosen, the Owners shall provide written notice to the City of Renton within
fifteen (15) days of receiving the City’s notice of inspection. Within thirty (30) days of giving this
notice, the Owners, or engineer on behalf of the Owners, shall provide the engineer’s report to
the City of Renton. If the report is not provided in a timely manner as specified above, the City
of Renton may inspect the drainage facilities without further notice.
3.If City of Renton determines from its inspection, or from an engineer’s report provided in
accordance with Paragraph 2, that maintenance, repair, restoration, and/or mitigation work is
required to be done to any of the drainage facilities, City of Renton shall notify the Owners of
the specific maintenance, repair, restoration, and/or mitigation work (“Work”) required
pursuant to the Renton Municipal Code. The City shall also set a reasonable deadline for the
Owners to complete the Work, or to provide an engineer’s report that verifies completion of
the Work. After the deadline has passed, the Owners shall allow the City access to re-inspect
the drainage facilities unless an engineer’s report has been provided verifying completion of
the Work. If the Work is not completed within the time frame set by the City, the City may
initiate an enforcement action and/or perform the Work and hereby is given access to the
Property for such purposes. Written notice will be sent to the Owners stating the City’s
intention to perform such Work. This Work will not commence until at least seven (7) days after
such notice is mailed. If, within the sole discretion of the City, there exists an imminent or
present danger, the seven (7) day notice period will be waived and Work will begin
immediately.
4.The Owners shall assume all responsibility for the cost of any Work, or any measures taken by
the City to address conditions as described in Paragraph 3. Such responsibility shall include
reimbursement to the City within thirty (30) days of the receipt of the invoice for any such Work
performed. Overdue payments will require payment of interest at the maximum legal rate
allowed by RCW 19.52.020 (currently twelve percent (12%)). If the City initiates legal action to
enforce this agreement, the prevailing party in such action is entitled to recover reasonable
litigation costs and attorney’s fees.
5.The Owners are required to obtain written approval from City of Renton prior to filling, piping,
cutting, or removing vegetation (except in routine landscape maintenance) in open vegetated
stormwater facilities (such as swales, channels, ditches, ponds, etc.), or performing any
alterations or modifications to the drainage facilities referenced in this Declaration of Covenant.
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6.Any notice or consent required to be given or otherwise provided for by the provisions of this
Agreement shall be effective upon personal delivery, or three (3) days after mailing by Certified
Mail, return receipt requested.
7.With regard to the matters addressed herein, this agreement constitutes the entire agreement
between the parties, and supersedes all prior discussions, negotiations, and all agreements
whatsoever whether oral or written.
8.This Declaration of Covenant is intended to protect the value and desirability and promote
efficient and effective management of surface water drainage of the real property described
above, and shall inure to the benefit of all the citizens of the City of Renton and its successors
and assigns. This Declaration of Covenant shall run with the land and be binding upon
Grantor(s), and Grantor's(s') successors in interest, and assigns.
9.This Declaration of Covenant may be terminated by execution of a written agreement by the
Owners and the City that is recorded by King County in its real property records.
IN WITNESS WHEREOF, this Declaration of Covenant for the Inspection and Maintenance of
Drainage Facilities is executed this _____ day of ____________________, 20_____.
GRANTOR, owner of the Property GRANTOR, owner of the Property
STATE OF WASHINGTON )
COUNTY OF KING )ss.
On this day personally appeared before me:
, to me known to be the individual(s)
described in and who executed the within and foregoing instrument and acknowledged that they
signed the same as their free and voluntary act and deed, for the uses and purposes therein stated.
Given under my hand and official seal this _____ day of ___________________, 20_____.
Printed name
Notary Public in and for the State of
Washington, residing at
My appointment expires
EXHIBIT A -ON-SITE BMP SITE PLAN
TOTAL LOT/SITE AREA: 10. 71 AC (466,538 SF) PERMIT#: C21006142 ADDRESS: 720 JONES AVE. S, PARCEL NUMBER: 202305-9059, RENTON, WA 98507 000720-0175
NEW/REPLACED IMPERV. AREA (SF): 67,518 SF DISTURBED AREA (SF): 239,580 SF (5.5 AC) ON-SITE BMP(S) USED: BASIC DISPERSION INFILTRATION TRENCHES, NATIVE GROWTH RETENTION TRACT, BIORETENTION, AND SOIL AMENDMENTS
I 7
I I
INFILTRATION TRENCH, TYP.
BASKETBALL COURT 4680 SF
r '-/ '--/ '--/' I EXISTING BASEBALL FIELD
SOIL AMENDMENT
NATIVE GROWTH RETENTION TRACT, TYP.
GAZEBO 1008 SF
GAZEBO 576 SF
NOTE: SOIL AMENDMENT
ONCRETE PATH 4,718 SF
BMP IS USED. SEE APPROVED PLANS R-421101 FOR MORE DETAILS. BIORETENTION
0 20 50 100 150 FT.
Page 4 of 20
MAINTENANCE INSTRUCTIONS FOR FULL DISPERSION
Your property contains an on-site BMP (best management practice) called “full dispersion.”
Full dispersion is a strategy for minimizing the area disturbed by development (i.e., impervious or nonnative pervious surfaces, such as concrete areas, roofs, and lawns) relative to native vegetated areas (e.g., forested surface) together with the application of dispersion techniques that utilize the natural
capacity of the native vegetated areas to mitigate the stormwater runoff quantity and quality impacts of the developed surfaces.
This on-site BMP has two primary components that must be maintained per Appendix A of the City of
Renton’s Surface Water Design Manual:
(1) the devices that disperse runoff from the developed surfaces, and
(2) the native vegetated area and flowpath receiving the dispersed runoff.
Dispersion Devices
The dispersion devices used on your property include the following as indicated on the site
plan (CHECK THE BOX(ES) THAT APPLY):
splash blocks, rock pads, gravel filled trenches, sheet flow.
MAINTENANCE RESTRICTIONS
The size, placement, composition, and downstream flowpaths of these devices as depicted by the site
plan and design details must be maintained and may not be changed without written approval from the City of Renton or through a future development permit from the City of Renton.
INSPECTION FREQUENCY AND MAINTENANCE GUIDELINES
Dispersion Devices
•Dispersion devices must be inspected annually and after major storm events to identify andrepair any physical defects.
•When native soil is exposed or erosion channels are present, the sources of the erosion or
concentrated flow need to be identified and mitigated.
•Bare spots should be re-vegetated with native vegetation.
•Concentrated flow can be mitigated by leveling the edge of the pervious area and/or regrading
or replenishing the rock in the dispersion device, such as in rock pads and gravel-filled
trenches.
Native Growth Retention Area
•The native vegetated surface required for full dispersion is delineated as a “native growthretention area” on the on-site BMP site plan. The trees, vegetation, ground cover, and soil
conditions in this area may not be disturbed, except as allowed by the following provisions for
that portion of the native growth retention area outside of critical areas and critical areabuffers:
1.Individual trees that have a structural defect due to disease or other defects, and which
threaten to damage a structure, road, parking area, utility, or place of employment or
Page 5 of 20
public assembly, or block emergency access, may be topped, pruned, or removed as needed to eliminate the threat.
2.Dead or fallen trees, tree limbs within ten feet of the ground, and branchesoverhanging a residence may be removed to reduce the danger of wildfire.
3. Noxious weeds (i.e., plant species listed on the State noxious weed list inChapter 16-750 WAC) and invasive vegetation (i.e., plant species listed as obnoxiousweeds on the noxious weed list adopted by King County) may be removed.
4.Passive recreation uses and related facilities, including pedestrian, equestriancommunity and bicycle trails, nature viewing areas, fishing and camping areas, andother similar uses that do not require permanent structures, are allowed if clearing andsoil compaction associated with these uses and facilities does not exceed eight percentof the native growth retention area.
RECORDING REQUIREMENT
These full dispersion on-site BMP maintenance and operation instructions must be recorded as an attachment to the required declaration of covenant and grant of easement per Requirement 3 of Section C.1.3.4 of the City of Renton Surface Water Design Manual. The intent of these instructions is
to explain to future property owners, the purpose of the BMP and how it must be maintained and operated. These instructions are intended to be a minimum; the City of Renton may require additional
instructions based on site-specific conditions. See the City of Renton’s Surface Water Design Manual
website for additional information and updates.
Page 6 of 20
TYPICAL FULL DISPERSION APPLICATIONS
SIDE VIEW
NTS
HOUSE
DOWNSPOUT
EXTENSION
SPLASHBLOCK
ROOF DOWNSPOUT
SPLASH BLOCK
100' MIN. VEGETATED
FLOWPATH UNDER
FULL DISPERSION,
SEE SECTION C.2.1.3
Page 7 of 20
TYPICAL FULL DISPERSION APPLICATIONS
Page 8 of 20
TYPICAL FULL DISPERSION APPLICATIONS
WIDTH = 25 FT FOR
A 100-FT NVFS
WIDTH = 50 FT FORA 200-FT NVFS
PLAN VIEW
NTS
CRUSHED ROCK STRIP
2-FT WIDE
= 5%
SLOPE
NATIVE VEGETATED
FLOWPATH SEGMENT
(NVFS)
=15% SLOPE
100 FT MINIMUM
EDGE OF
UNDISTURBED NATIVE
VEGETATION
Page 9 of 20
MAINTENANCE INSTRUCTIONS FOR FULL INFILTRATION
Your property contains an on-site BMP (best management practice) called “full infiltration,” which
was installed to mitigate the stormwater quantity and quality impacts of some or all of the impervious surfaces on your property.
Full infiltration is a method of soaking runoff from impervious area (such as paved areas and roofs)
into the ground. If properly installed and maintained per Appendix A of the City of Renton’s Surface Water Design Manual, full infiltration can manage runoff so that a majority of precipitation events are
absorbed. Infiltration devices, such as gravel filled trenches, drywells, and ground surface depressions,
facilitate this process by putting runoff in direct contact with the soil and holding the runoff long enough to soak most of it into the ground. To be successful, the soil condition around the infiltration
device must be reliably able to soak water into the ground for a reasonable number of years.
Infiltration Devices
The infiltration devices used on your property include the following as indicated on the site
plan (CHECK THE BOX(ES) THAT APPLY):
gravel filled trenches, drywells, ground surface depressions.
MAINTENANCE RESTRICTIONS
The size, placement, and composition of these devices as depicted by the site plan and design details
must be maintained and may not be changed without written approval from the City of Renton or through a future development permit from the City of Renton.
INSPECTION FREQUENCY AND MAINTENANCE GUIDELINES
•Infiltration devices must be inspected annually and after major storm events to identify and
repair any physical defects.
•Maintenance and operation of the system should focus on ensuring the system’s viability by
preventing sediment-laden flows from entering the device. Excessive sedimentation will result
in a plugged or non-functioning facility.
•If the infiltration device has a catch basin, sediment accumulation must be removed on a yearly
basis or more frequently if necessary.
•Prolonged ponding around or atop a device may indicate a plugged facility. If the device
becomes plugged, it must be replaced.
•Keeping the areas that drain to infiltration devices well swept and clean will enhance the
longevity of these devices.
•For roofs, frequent cleaning of gutters will reduce sediment loads to these devices.
Page 10 of 20
RECORDING REQUIREMENT
These full infiltration on-site BMP maintenance and operation instructions must be recorded as an
attachment to the required declaration of covenant and grant of easement per Requirement 3 of Section C.1.3.4 of the City of Renton Surface Water Design Manual. The intent of these instructions is
to explain to future property owners, the purpose of the BMP and how it must be maintained and operated. These instructions are intended to be a minimum; the City of Renton may require additional instructions based on site-specific conditions. See the City of Renton’s Surface Water Design Manual
website for additional information and updates.
Page 11 of 20
TYPICAL FULL INFILTRATION APPLICATIONS
6"
24"
12"
24"
WASHED ROCK 1 12"- 34"
LEVEL
INFILTRATION TRENCH
SECTION ANTS
PLAN VIEWNTS
SECTION VIEW
NTS
VARIES
A
A
6"
6"
4" RIGID OR 6"FLEXIBLEPERFORATEDPIPE
CB SUMP w/SOLID LID ROOF DRAIN
4" RIGID OR 6" FLEXIBLEPERFORATED PIPE
OVERFLOW
SPLASH BLOCK
ROOF DRAIN
CB SUMP w/SOLID LID
12"
FINE MESHSCREEN
SETBACKFROMBUILDING5' MIN.
1' MIN.1' MIN.
FILTER FABRIC
COMPACTED BACKFILL
4" RIGID OR 6" FLEXIBLE
PERFORATED PIPE
112" - 34" WASHED ROCK
MIN. 1' ABOVE SEASONALHIGH GROUNDWATERTABLE, SEE SECTION C.2.2.2
TRENCH SETBACK FROMBUILDING AS REQUIRED,15' MIN.
DRIVEWAY
X-SECTION
NTS
2' MIN.
FILTER STRIPSEE SECTIONS6.3.4 & 6.3.5
18" MIN.
6" MIN.
3/4" TO 1-1/2"WASHED DRAINROCK
GRASS
OVERFLOW
NOTE:SEE C.2.2.3 FOR
TRENCH LENGTHS,TRENCH SPACING ANDSITE LIMITATIONS
MIN. 1' ABOVESEASONAL HIGHGROUNDWATERTABLE, SEESECTION C.2.2.2
X-SECTION
NTS
GRASS
2' MIN.
18" MIN.
6" MIN.
3/4" TO 1-1/2"WASHED DRAINROCK
OVERFLOW
15' MIN. ASREQUIRED,SEE C.2.2.3
FROM ROOF
NS T T S MIN. 1' ABOVESEASONAL HIGHGROUNDWATERTABLE, SEESECTION C.2.2.2
HOUSE
FLOW
48 INCH DIAMETERHOLE FILLED WITH
1 12" - 3" WASHEDDRAIN ROCK
SECTIONNTS
MARK CENTER OF HOLEWITH 1" CAPPED PVCOR OTHER MEANSFLUSH WITH SURFACE
ROOF DOWNSPOUT
OVERFLOW
SPLASH BLOCK TOPSOIL
FINE MESH SCREEN
MIN. 4" DIA.PVC PIPE
SIDES OF HOLELINED WITHFILTER FABRIC
CATCH BASIN(YARD DRAIN)
15' MIN. AS REQUIRED, SEE SECTION C.2.2.3
VARIES
1' MIN.
MIN. 1' ABOVE SEASONALHIGH GROUNDWATER TABLE,SEE SECTION C.2.2.2
5' MIN. SETBACKFROM BUILDING
FLOW
PLAN VIEWNTS
HOUSE
ROOFDOWNSPOUT
ROOFDOWNSPOUT
CATCH BASIN(YARD DRAIN)
48 INCH DIAMETERHOLE FILLED WITH1 12" - 3" WASHEDDRAIN ROCK
Page 12 of 20
MAINTENANCE INSTRUCTIONS FOR LIMITED INFILTRATION
Your property contains an on-site BMP (best management practice) called “limited infiltration,” which
was installed to mitigate the stormwater quantity and quality impacts of some or all of the impervious
surfaces on your property.
Limited infiltration is a method of soaking runoff from impervious area (such as paved areas and roofs)
into the ground. Infiltration devices, such as gravel filled trenches, drywells, and ground surface
depressions, facilitate this process by putting runoff in direct contact with the soil and holding the runoff long enough to soak most of it into the ground. To be successful, the soil condition around the
infiltration device must be able to soak water into the ground for a reasonable number of years. This on-site BMP shall be maintained per Appendix A of the City of Renton’s Surface Water Design Manual.
Infiltration Devices
The infiltration devices used on your property include the following as indicated on the site plan (CHECK THE BOX(ES) THAT APPLY):
gravel filled trenches, drywells
MAINTENANCE RESTRICTIONS
The size, placement, and composition of these devices as depicted by the site plan and design details
must be maintained and may not be changed without written approval from the City of Renton or through a future development permit from the City of Renton.
INSPECTION FREQUENCY AND MAINTENANCE GUIDELINES
To be successful, the soil condition around the infiltration device must be able to soak water into the ground for a reasonable number of years.
•Infiltration devices must be inspected annually and after major storm events to identify andrepair any physical defects.
•Maintenance and operation of the system should focus on ensuring the system's viability bypreventing sediment-laden flows from entering the device. Excessive sedimentation will result
in a plugged or non-functioning facility.
•If the infiltration device has a catch basin, sediment accumulation must be removed on a yearlybasis or more frequently if necessary.
•Prolonged ponding around or atop a device may indicate a plugged facility. If the devicebecomes plugged, it must be replaced.
•Keeping the areas that drain to infiltration devices well swept and clean will enhance thelongevity of these devices.
•For roofs, frequent cleaning of gutters will reduce sediment loads to these devices.
Page 13 of 20
RECORDING REQUIREMENT
These limited infiltration on-site BMP maintenance and operation instructions must be recorded as an
attachment to the required declaration of covenant and grant of easement per Requirement 3 of Section C.1.3.4 of the City of Renton Surface Water Design Manual. The intent of these instructions is
to explain to future property owners, the purpose of the BMP and how it must be maintained and operated. These instructions are intended to be a minimum; the City of Renton may require additional instructions based on site-specific conditions. See the City of Renton’s Surface Water Design Manual
website for additional information and updates.
Page 14 of 20
INFILTRATION TRENCH AND DRYWELL SYSTEMS
6"
24"
12"
24"
WASHED ROCK 1 12"- 34"
LEVEL
INFILTRATION TRENCH
SECTION A
NTS
PLAN VIEWNTS
SECTION VIEWNTS
VARIES
A
A
6"
6"
4" RIGID OR 6"FLEXIBLEPERFORATEDPIPE
CB SUMP w/SOLID LID ROOF DRAIN
4" RIGID OR 6" FLEXIBLEPERFORATED PIPE
OVERFLOW
SPLASH BLOCK
ROOF DRAIN
CB SUMP w/SOLID LID
12"
FINE MESHSCREEN
SETBACKFROMBUILDING5' MIN.
1' MIN.1' MIN.
FILTER FABRIC
COMPACTED BACKFILL
4" RIGID OR 6" FLEXIBLEPERFORATED PIPE
112" - 34" WASHED ROCK
MIN. 1' ABOVE SEASONAL
HIGH GROUNDWATER
TABLE, SEE SECTION C.2.2.2
TRENCH SETBACK FROMBUILDING AS REQUIRED,15' MIN.
DRIVEWAY
X-SECTION
NTS
2' MIN.
FILTER STRIP
SEE SECTIONS6.3.4 & 6.3.5
18" MIN.
6" MIN.
3/4" TO 1-1/2"WASHED DRAINROCK
GRASS
OVERFLOW
NOTE:SEE C.2.2.3 FORTRENCH LENGTHS,
TRENCH SPACING ANDSITE LIMITATIONS
MIN. 1' ABOVESEASONAL HIGHGROUNDWATERTABLE, SEESECTION C.2.2.2
X-SECTIONNTS
GRASS
2' MIN.
18" MIN.
6" MIN.
3/4" TO 1-1/2"WASHED DRAINROCK
OVERFLOW
15' MIN. ASREQUIRED,SEE C.2.2.3
FROM ROOF
NS T T S MIN. 1' ABOVESEASONAL HIGHGROUNDWATERTABLE, SEESECTION C.2.2.2
HOUSE
FLOW
48 INCH DIAMETERHOLE FILLED WITH
1 12" - 3" WASHEDDRAIN ROCK
SECTIONNTS
MARK CENTER OF HOLEWITH 1" CAPPED PVCOR OTHER MEANSFLUSH WITH SURFACE
ROOF DOWNSPOUT
OVERFLOW
SPLASH BLOCK TOPSOIL
FINE MESH SCREEN
MIN. 4" DIA.PVC PIPE
SIDES OF HOLELINED WITHFILTER FABRIC
CATCH BASIN(YARD DRAIN)
15' MIN. AS REQUIRED, SEE SECTION C.2.2.3
VARIES
1' MIN.
MIN. 1' ABOVE SEASONALHIGH GROUNDWATER TABLE,SEE SECTION C.2.2.2
5' MIN. SETBACKFROM BUILDING
FLOW
PLAN VIEWNTS
HOUSE
ROOFDOWNSPOUT
ROOFDOWNSPOUT
CATCH BASIN(YARD DRAIN)
48 INCH DIAMETERHOLE FILLED WITH1 12" - 3" WASHEDDRAIN ROCK
Page 15 of 20
MAINTENANCE INSTRUCTIONS FOR NATIVE GROWTH RETENTION CREDIT
Your property contains an on-site BMP (best management practice) known as “native growth
retention,” the practice of preserving a portion of a property in a native vegetated condition (e.g., forest) so as to minimize increases in stormwater runoff from clearing and to offset the stormwater runoff impacts caused by impervious surfaces on your property.
This native vegetated area on your property was set aside by covenant as “native growth retention
area.” This on-site BMP shall be maintained per Appendix A of the City of Renton’s Surface Water Design Manual.
MAINTENANCE RESTRICTIONS
The “native growth retention area” is delineated on the site plan attached to the covenant. The trees,
vegetation, ground cover, and soil conditions in this area may not be disturbed, except as allowed by
the following provisions:
1.Trees may be harvested in accordance with a King County-approved forest management plan if
approved by King County prior to annexation to the City.
2.Individual trees that have a structural defect due to disease or other defects, and which threatento damage a structure, road, parking area, utility, or place of employment or public assembly,
or block emergency access, may be topped, pruned, or removed as needed to eliminate thethreat.
3. Dead or fallen trees, tree limbs within ten feet of the ground, and branches overhanging a
residence may be removed to reduce the danger of wildfire.
4. Noxious weeds (i.e., plant species listed on the State noxious weed list in Chapter 16-750WAC) and invasive vegetation (i.e., plant species listed as obnoxious weeds on the noxious
weed list adopted by King County) may be removed.
5.Passive recreation uses and related facilities, including pedestrian, equestrian community and
bicycle trails, nature viewing areas, fishing and camping areas, and other similar uses that do
not require permanent structures, are allowed if clearing and soil compaction associated withthese uses and facilities does not exceed eight percent of the native growth retention area.
RECORDING REQUIREMENT
These native growth retention credit on-site BMP maintenance and operation instructions must be recorded as an attachment to the required declaration of covenant and grant of easement per
Requirement 3 of Section C.1.3.4 of the City of Renton Surface Water Design Manual. The intent of these instructions is to explain to future property owners, the purpose of the BMP and how it must be
maintained and operated. These instructions are intended to be a minimum; the City of Renton) may
require additional instructions based on site-specific conditions. See the City of Renton’s Surface Water Design Manual website for additional information and updates.
Page 16 of 20
MAINTENANCE INSTRUCTIONS FOR A BIORETENTION CELL
Your property contains an on-site BMP (best management practice) called “bioretention,” which was
installed to mitigate the stormwater quantity and quality impacts on both the impervious (paved or
roof) and pervious surfaces (lawn or landscape) on your property.
Bioretention cells, like rain gardens, are vegetated closed depressions or ponds that retain and filter
stormwater from an area of impervious surface or nonnative pervious surface. Bioretention cells rely
on effective infiltration performance more so than rain gardens. The soil in the bioretention cell has been enhanced to encourage and support vigorous plant growth that serves to filter the water and
sustain a minimum infiltration capacity. Depending on soil conditions, bioretention cells may have water in them throughout the wet season and may overflow during major storm events. However, standing water can also be an indicator that periodic maintenance is required to sustain infiltrative
performance. This on-site BMP shall be maintained per Appendix A of the City of Renton’s Surface Water Design Manual.
MAINTENANCE RESTRICTIONS
The size, placement, and design of the rain garden as depicted by the site plan and design details must be maintained and may not be changed without written approval from the City of Renton or through a
future development permit from the City of Renton. Chemical fertilizers and pesticides must not be used.
INSPECTION FREQUENCY AND MAINTENANCE GUIDELINES
•Bioretention cells must be inspected annually for physical defects and sediment accumulation.
•Bioretention cells have inflow and overflow inlets and outlets. These need to be maintained toensure that water is moving into and out of the bioretention area. Check inlets/outlets fordebris/sediment blockage, bare spots (exposed soil), or other signs of erosion damage (soil
movement). Remove debris and obstructions as necessary.
•After major storm events, the bioretention cell should be checked to see that the overflow
system is working properly and sedimentation is not occurring at the inlet. If erosion damage
or bare spots are evident, they should be stabilized with soil, plant material, mulch, orlandscape rock. Sediment deposits should be carefully removed and the sediment source
eliminated.
•Plants must be adapted to wet winter conditions and dry summer conditions. Vegetation is to
be watered and pruned as needed.
•Frequent watering is required to keep the plants healthy:
o Year 1: weekly,
o Year 2: bimonthly,
o Year 3: bimonthly,
o Year 4 and beyond: as needed for established plantings and dry periods.
•Chemical fertilizers and pesticides must not be used.
•Bioretention soil must be replaced in areas where sediment accumulation is preventing
adequate infiltration of water through the soil.
Page 17 of 20
•Compacted soil should be decompacted.
•Trash and debris must be removed often from the bioretention depression.
•Mulch must be applied to bare soil at a minimum of 2 inches to maintain healthy growth.
•Compost may be added if soil nutrients are no longer adequate to support plant growth.
•Plant materials may be changed to suit tastes.
•Vegetation should be maintained as follows:
1) Replace all dead vegetation as soon as possible;
2) Remove fallen leaves and debris as needed;
3) Remove all noxious vegetation when discovered;
4) Manually weed without herbicides or pesticides;
5) To protect infiltration performance, do not compact soils in the bioretention cell with heavymaintenance equipment and/or excessive foot traffic;
6) During drought conditions, use mulch to prevent excess solar damage and water loss.
RECORDING REQUIREMENT
These bioretention on-site BMP maintenance and operation instructions must be recorded as an
attachment to the required declaration of covenant and grant of easement per Requirement 3 of Section C.1.3.4 of the City of Renton Surface Water Design Manual. The intent of these instructions is
to explain to future property owners, the purpose of the BMP and how it must be maintained and
operated. These instructions are intended to be a minimum; the City of Renton may require additional instructions based on site-specific conditions. See the City of Renton’s Surface Water Design Manual
website for additional information and updates.
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TYPICAL BIORETENTION CELL (SPILLWAY OR CATCH BASIN OUTLET)
TREES, SHRUBS
GROUND COVER
BIORETENTION AREA
PLAN VIEW
NTS
VEGETATEDCOMPACTEDEARTH BERM
ROCKED SPILLWAY, 2'Wx4'L
(OR BEYOND BERM IF
LONGER), OVERFLOW TOSUITABLE DISCHARGE AREA
TREES, SHRUBS
GROUND COVER
BIORETENTION AREA
PLAN VIEW
NTS
VEGETATED
COMPACTED
EARTH BERM,
TOP WIDTH2' MIN
4" RIGID PIPE OUTLET
TO STORM SYSTEM
CATCH BASINw/GRATE
SECTION A-ANTS
BIORETENTION AREA
GROUNDCOVER
TREES TREES
SHRUBS
6" MIN TO 12" MAX
WATER DEPTH
OVERFLOW TO
SUITABLE SURFACEDISCHARGE AREA
2' MIN TOP WIDTH
COMPACTED EARTHBERM (AS NEEDED)
6" MIN FREEBOARD
ABOVE OVERFLOW WS
TO TOP OF BERM OR
ADJACENT ROADWAY
BIORETENTIONSOIL MIX PERREFERENCE 11-C,
MIN.18" DEPTH
MAX SLOPE 3H:1V BELOW
OVERFLOW WATERSURFACE ELEVATION (TYP.)
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MAINTENANCE INSTRUCTIONS FOR SOIL AMENDMENT
Your property contains an on-site BMP (best management practice) called “soil amendment,” which
was installed to mitigate the stormwater quantity and quality impacts of some or all of the pervious
surfaces on your property.
Soil amendment is a method of regaining greater stormwater functions in the post development
landscape by increasing treatment of pollutants and sediments, and minimizing the need for some
landscaping chemicals. To be successful, the soil condition must be able to soak water into the ground for a reasonable number of years. This on-site BMP shall be maintained per Appendix A of the City of
Renton’s Surface Water Design Manual.
MAINTENANCE RESTRICTIONS
The size, placement, and composition of these devices as depicted by the site plan and design details
must be maintained and may not be changed without written approval from the City of Renton or through a future development permit from the City of Renton.
INSPECTION FREQUENCY AND MAINTENANCE GUIDELINES
To be successful, the soil must be able to soak water into the ground for a reasonable number of years.
•Return leaf fall and shredded woody materials from the landscape to the site when possible inorder to replenish soil nutrients and structure.
•On turf areas, “grasscycle” (mulch-mow or leave the clippings) to build turf health.
•Maintain 2 to 3 inches of mulch over bare areas in landscape beds.
•Re-seed bare turf areas until the vegetation fully covers the ground surface.
•Avoid using pesticides (bug and weed killers) which damage the soil.
•Where fertilization is needed (mainly turf and annual flower beds), a moderate fertilizationprogram should be used which relies on compost, natural fertilizers, or slow-release syntheticbalanced fertilizers.
RECORDING REQUIREMENT
These on-site BMP maintenance and operation instructions must be recorded as an attachment to the
required declaration of covenant and grant of easement per Requirement 3 of Section C.1.3.4 of the
City of Renton Surface Water Design Manual. The intent of these instructions is to explain to future property owners, the purpose of the BMP and how it must be maintained and operated. These
instructions are intended to be a minimum; the City of Renton may require additional instructions based on site-specific conditions. See the City of Renton’s Surface Water Design Manual website for additional information and updates.
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