HomeMy WebLinkAboutPAR2008-00039 Large Parcel Stormwater Plan - PAR Plot / Site Plans - 10/13/2008 TAHJA ENGINEERING, Inc.
PO Box 235, Hoodsport, WA 98548
(360) 877-9512
Mason County DCD
Planning Department
PO Box 279
Shelton, WA 98584
�i
Dwight S. MaKa� Y
590 E Island Lake Drive
Shelton, WA 98584-7821
(360)426-5975
Large Parcel Stormwater Site Plan(LPSSP)
Mason Co. Case No.s PAR2008-00039
Mason Co. Prcl Nos. 420.12-21-90003 & 90004
Stormwater Site Plan Narrative
Mr. McKay is proposing to develop two commercial properties he owns located off of the Shelton-
Springs Road north of Shelton. The two parcels are each over an acre in size and are proposed to
be developed with storage buildings and impervious surfaces exceeding 5000 square feet on each
of the two properties. Mason County's Stormwater Management Ordinance requires the
preparation of a Large Parcel Stormwater Site Plan(LPSSP)for development activities which
include in excess of an acre of clearing, or the creation of 5,000 square feet of new impervious
surfacing.
The Stormwater Site Plan is required to include a Large Parcel Erosion and Sediment Control
(ESC)Plan and a Permanent Stormwater Quality Control (PSQC)Plan which includes measures
needed to protect neighboring properties and State waters from adverse stormwater runoff impacts.
The McKay properties each drain towards the southwesterly corner of each site. Construction
sequencing should be initiated with the roughing out of the stormwater ponds designed for the
permanent stormwater quality control plan which will provide protection of neighboring properties
through the final development of each of the two sites. Directing construction area runoff into the
pond on each site, and maintaining the two ponds and removing any sediment build up resulting
from construction activities should satisfy the Large Parcel Erosion and Sediment Control Plan
requirements of the County Stormwater Management Ordinance.
This document is intended to provide the necessary documentation required for approval of a
Large Parcel Activity associated with clearing in excess of an acre of lightly vegetated land and
conversion of the cleared property to a predominantly impervious condition consisting of building
roofs and gravel driveways and parking areas. This conversion requires compliance with
Stormwater Management Ordinance requirements #1 through#11 in subsections 3 through 13
of Mason County Chapter 14.48 Stormwater Management Ordinance. The followingpages are
pg
intended to meet the requirements of the County's Stormwater Management Ordinance narrative
Mason Count
y Stormwater Management version of Ecology's 1992 Stormwater Management Manual for the Puget
Sound Basin g
File:C.,WrojectsWcKayWP 1 of 7 10/13/2008
TAHJA ENGINEERING, Inc.
PO Box 235, Hoodsport, WA 98548
(360) 877-9512
requirements. Plan sheets representing the Stormwater Site Plan and plan design features follow
this portion of the required documents. Included in the appendix of this report will also be found
supporting StormShed2G printouts which provide the basis for the retention pond sizing and
supporting documentation. Also included in the appendix material is a copy of the Operation and
Maintenance (O&M) Covenant required by the County to be completed, notarized, and recorded
with the County Auditor's Office as part of the LPSSP approval by the County.
Minimum Requirement#1: Erosion and Sediment Control
The following E&S Control Requirements will be incorporated into the site development activities
to the greatest extent practical:
E&S Requirement#1: Stabilization and Sediment Trapping. All exposed and unworked soils shall be
stabilized by suitable application of BMPs. From October 1 to April 30, no exposed and unworked soils
shall remain unstabilized for more than two days. From May 1 to September 30, no exposed and
unworked soils shall remain unstabilized for more than seven days. Prior to leaving the site, stormwater
runoff shall pass through a sediment pond or sediment trap, or other appropriate BMPs.
As indicated in this document's introduction,the first step in the property's developments should
be the roughing out of the stormwater retention ponds designed for each site, and the rough
grading of the properties to direct all surface runoff to each pond. The ponds are designed to be
excavated below the surrounding ground levels and can be expected to intercept runoff from each
of the construction areas. The ponds are designed to infiltrate stormwater storm events up to and
including a 100 year 24 hour event.
E&S Requirement 42: Delineate Clearing and Easement Limits. In the field, mark clearing limits
and/or any easements, setbacks, sensitive%ritical areas and their buffers, trees and drainage courses.
The attached site plans indicate the general clearing limits and stormwater collection basins. Mr.
McKay is intending to reduce the County's required vegetated buffers to half the 20-foot
requirement by doubling the required plantings in the buffer strips surrounding each property.
These buffer areas should be planted as early as practical during the construction phase of the site
development, and should include a grass or clover groundcover vegetation or beauty bark
application to protect the surface soils from erosion. The two retention ponds will encompass most
or all of the southerly vegetated buffer on each property,but the slopes above the two year stone
event water elevation should be planted with grass in addition to the County's planting
requirements to provide stabilization of the pond slopes. Only rarely(less the 98%of the time)will
the slopes above the 2 year 24 hour event will be submerged,and the ponds are designed to drain
themselves in roughly 24 hours.
E&S Requirement#3:Protection of Adjacent Properties. Properties adjacent to the project site shall be
protected from damage by sediment deposition.
The two retention ponds were sized by modeling 24-hour storm events from the 6-month storm
size to the 100-year event storm size. All surface runoff from the properties will be eliminated,
providing the required protection of adjacent properties.
E&S Requirement#4: Timing and Stabilization of Sediment Trapping Measures. Sediment ponds and
traps, perimeter dikes, sediment barriers, and other BMPs intended to trap sediment on-site shall be
File:C lProjectsWcKayMP 2 of 7 10/13/2008
TAHJA ENGINEERING, Inc.
PO Box 235, Hoodsport, WA 98548
(360) 877-9512
constructed as a first step in grading. These BMPs shall be functional before land disturbing activities
take place. Earthen structures such as dams, dikes, and diversions shall be seeded and mulched
according to the timing indicated in Erosion and Sediment Control Requirement#1.
The two stormwater retention ponds developed for this stormwater management plan should be
roughed out as soon as possible, and the areas surrounding each pond should be graded to deliver
stormwater runoff to them to provide runoff treatment as soon as possible.
E&S Requirement#5: Cut and Fill Slopes. Cut and fill slopes shall be designed and constructed in a
manner that will minimize erosion. In addition, slopes shall be stabilized in accordance with erosion and
sediment control requirement#1.
The current site development plans do not create any major cut or fill slopes. The two ponds
included in this plan are designed with 2:1 (H:V) sideslopes which should be stable when
submerged, and should be shallow enough to sustain vegetation.
E&S Requirement#6: Controlling Off-Site Erosion. Properties and waterways downstream from
development sites shall be protected from damage by erosion due to increases in the volume, velocity,
or peak flow rate of stormwater runoff from the project site.
The retention ponds designed for the built-out sites eliminates post development surface
discharges. The pre-developed site may have had a discharge of surface stormwater runoff but no
point discharge was or is easily discernable, so no developed site point discharges are being
promoted in this stormwater control plan.
E&S Requirement#7: Stabilization of Temporary Conveyance Channels and Outlets. All temporary on-
site conveyance channels shall be designed, constructed and stabilized to prevent erosion from the
expected velocity of the peak flow from a two-year, twenty-four hour frequency storm for the developed
condition. Stabilization adequate to prevent erosion of outlets, adjacent streambanks, slopes and
downstream reaches shall be provided at the outlets of all conveyance systems.
Stormwater runoff delivery from driving & parking areas to the retention ponds is intended to be in
a sheet flow regime. Roof runoff will either be delivered directly to the retention ponds, or to
dispersion pads installed in the perimeter vegetated buffer of each parcel. Parking and driveway
area runoff will be sheeted to the retention ponds by grading the site to deliver un-concentrated
flows of stormwater runoff to each retention pond. Without a surface discharge from the site for
storm events through the 100 year 24 hour event, there should be no surface runoff delivered off
the site, or to neighboring properties.
E&S Requirement #8: Storm Drain Inlet Protection. All storm drain inlets made operable during
construction shall be protected so that stormwater runoff shall not be discharged offsite or be
introduced into any fill area without first being filtered or otherwise treated to remove sediment.
The McKay development plans require no catch basins, but relies on shallow surface flow and site
grading to deliver stormwater runoff to the retention/treatment ponds.
E&S Requirement #9: Underground Utility Construction. The construction of underground utility lines
shall be subject to the following criteria:
(i) No more than five hundred feet of trench shall be opened at one time, unless provisions are
made to protect against adverse stormwater impacts.
File: CTrojectsGticKayISSP 3 of 7 10/13/2008
TAHJA ENGINEERING, Inc.
PO Box 235, Hoodsport, WA 98548
(360) 877-9512
(ii) Where consistent with safety and space considerations, excavated material shall be placed on
the uphill side of trenches.
These requirements should be made conditions for project approval and permitting.
E&S Requirement #10: Construction Access Routes.
(i) Construction vehicle access shall be, whenever possible, limited to one route. Access points
shall be stabilized to minimize the tracking of sediment onto public roads.
(ii) Wherever construction vehicle access routes intersect paved roads, provisions must be made to
minimize the transport of sediment(mud) onto the paved road. If sediment is transported onto a
road surface creating a hazard, the roads shall be cleaned immediately, and thoroughly cleaned at
the end of each day. Sediment shall be removed from roads by shoveling or sweeping and be
transported to a controlled sediment disposal area. Street washing shall be allowed only after
sediment is removed in this manner.
The site already includes an existing access located off of the Shelton Springs Road which includes
an asphalt paved surface. The access driveway is constructed from the relatively clean natural
gravels underlying the site and is stable in its present condition. Mr. McKay has expressed his
intention of applying a crushed rock or rock chip driving surface on the parking and driving areas
of the finished site. The surfacing materials are expected to provide additional runoff treatment to
stormwater runoff developed on the site in addition to the treatment/retention of the 6 month 24
hour storm event.
E&S Requirement 411: Removal of Temporary BMPs. All temporary erosion and sediment
control BMPs shall be removed within thirty days after final site stabilization is achieved or after the
temporary BMPs are no longer needed. Trapped sediment shall be removed or stabilized on site.
Disturbed soil areas resulting from removal shall be permanently stabilized.
Completion of the sites' developments will include excavating the roughed out stormwater
retention ponds to their design dimensions and planting of the vegetations recommended in this
report, and required by the County.
E&S Requirement 412: Dewatering Construction Sites. Trench dewatering devices shall be
discharged in a manner that will not adversely affect flowing streams, drainage systems or off-site
property. Water discharged from dewatering pumps shall be routed through a sediment pond or
trap unless it is clear.
The site enjoys highly permeable soils and no deep excavations will be required for site
development grading.
E&S Requirement#13: Control of Pollutants Other than Sediment on Construction Sites. All
pollutants other than sediment that occur on-site during construction shall be handled and disposed
of in a manner that does not cause contamination of stormwater.
This requirement should be made a condition of permit approval. Construction machinery used in
the sites' developments should be maintained to a degree that neither lubricants or fuels are
released or spilled within the construction area or elsewhere.
File:C:IProjectsWcKaySSP 4 of 7 10/13/2008
TAHJA ENGINEERING, Inc.
PO Box 235, Hoodsport, WA 98548
(360) 877-9512
E&S Requirement #14: Maintenance. All temporary and permanent erosion and sediment control
BMPs shall be maintained and repaired as needed and in a timely manner to assure continued
performance of their intended function. All maintenance and repair shall be conducted in
accordance with an approved manual.
An Operation and Maintenance (O&M) Covenant form has been prepared for each of the two
commercial properties. The main maintenance the stormwater management features are expected
to require is the periodic inspection of the ponds to verify that they are functioning in compliance
with their design target rates (infiltration rates and storm event water elevations). Water elevations
exceeding design parameters should be considered a signal that silt removal and disposal off-site is
needed. Silt and sediment removed from the retention ponds should be disposed of at an approved
(County permitted) disposal location. Silts and sediments removed from the retention pond dead
storage areas of the ponds is not expected to have very high levels of contamination, but should be
checked for possible contamination from ruptured tanks or other automotive related contaminants
and disposed of accordingly.
Minimum Requirement#2:Preservation of Natural Drainage Systems. Natural drainage
patterns shall be maintained, and discharges from the site shall occur at the natural location to the
maximum extent practicable.
The existing site does not exhibit any heavy flow discharge locations to off-site receiving areas.
The proposed retention of stormwater precipitation is felt to be a reasonable preservation of pre-
developed conditions and drainage patterns. Site soils are found to be a Soil Conservation Service
Grove Gravelly Sandy Loam termed excessively drained. Stormwater management of the site
includes the development of two stormwater retention ponds which preserve the pre-developed
natural drainage system.
Minimum Requirement#3: Source Control of Pollution. Source control BMPs shall be applied to
all projects to the maximum extent practicable. Source control BMPs shall be selected, designed,
and maintained according to an approved manual.
This is integral to the stormwater management plan design.
Minimum Requirement#4: Runoff Treatment BMPs. All ro ject p � s shall provide treatment of
storm
water Treatment BMPs shall be sized to capture and treat the water qualitystorm defined as
the six-month twenty-four h
y our storm. The first priority for treatment of stormwater shall be to
infiltrate as much as possible of the water quality q y design storm into the ground.
The retention pond designs provide for complete retention of the water quality q y design storm, and
storms sized through the 100 year 24 hour event storm. The infiltra
tion rate used in the retention
pond modeling is considered to represent half the natural al infiltration rate available.
Minimum Requirement#S: Streambank Erosion Control. The requirement below applies only to
situations where stormwater runoff is discharged directly or indirectly to a stream, and must be met
in addition to meeting the requirements in minimum requirement#4, Runoff Treatment BMPs:
Stormwater discharges to streams shall control streambank erosion by limiting the peak rate of
runoff from individual development sites to fifty percent of the existing condition two-year, twenty-
four hour design storm while maintaining the existing condition peak runoff rate for the ten-year,
twenty-four-hour and one hundred-year, twenty-four-hour design storms. As the first priority,
streambank erosion control BMPs shall utilize infiltration to the fullest extent practicable, only if site
File:C:IPrgiectsWcKayLS'_CP 7 n/1 I/�A00
J/LV0
TAHJA ENGINEERING, Inc.
PO Box 235, Hoodsport, WA -98548
(360) 877-9512
conditions are appropriate and ground water quality is protected. Streambank erosion control BMPs
shall be selected, designed, and maintained according to an approved manual.
The proposed retention pond designs reduces each sites' discharge to zero, providing erosion and
silt protection to downstream properties and compliance with downstream erosion control
discharge rates.
Minimum Requirement#6: Wetlands. Stormwater discharges to wetlands shall maintain the
wetland's natural hydroperiod and flows to the extent needed to preserve or enhance its existing
functions and values. Prior to proposing discharge of higher volumes of stormwater to a wetland,
alternative discharge, detention, and infiltration practices located in areas outside the wetland shall
be evaluated and employed by the project engineer where feasible and practicable.
No wetlands have been identified on or near the McKay property.
Minimum Requirement#7: Water Quality Sensitive Areas. Where the Mason County
commissioners or their designee determine that the minimum requirements do not provide
adequate protection of water quality sensitive areas, either on-site or within the basin, more
stringent controls shall be required to protect water quality. An adopted and implemented basin plan
(minimum requirement#9) may be used to develop requirements for water quality sensitive areas
that are tailored to a specific basin.
The McKay property is not located in an area requiring a higher degree of protection than the
proposed plan provides, nor is it located within a known or adopted basin plan.
Minimum Requirement#8: Off-Site Analysis and Mitigation. Downstream Analysis May Trigger
Additional Requirements. The project engineer shall provide a detailed qualitative analysis of the
flow path of the discharge from the project site to the receiving water. This requirement shall apply
to all projects where a drainage and erosion control plan is prepared, including those proposing
retention facilities. This analysis shall include flow routing, and provide existing pipe and channel
sizes and estimated capacities. In addition, the project engineer shall discuss any known or
expected downstream erosion, flooding, or water quality problems, including those that may be
caused by interflow from the proposed retention facility.
The McKay property receives little or no runoff from adjacent properties. Retention of stormwater
runoff and infiltration into the ground is expected to relieve the project from downstream analysis
or mitigation requirements. Interflow is expected to roughly match pre-development interflow
rates.
Minimum Requirement#9: Basin Planning. Basin plan supersedes Manual.
If a proposed project is located in a basin or sub basin for which the county has an adopted basin
plan, stormwater requirements specifically identified in the basin plan shall take precedence over
those provided in this chapter. However, all other elements detailed in this chapter shall continue to
apply to such projects. Basin plans are required to be developed according to an approved manual.
The McKay property is not located within a known adopted basin plan area.
Minimum Requirement#10: Operation and Maintenance. An operation and maintenance
schedule shall be provided for all proposed stormwater facilities and BMPs, and the party(or
parties)responsible for maintenance and operation shall be identified. An operation and
maintenance (O&M) covenant will be required to cover all privately owned and maintained
stormwater facilities approved by the director.
File: C:IProjectsWcKayMP 6 of 7 10/13/2008
TAHJA ENGINEERING, Inc.
PO Box 235, Hoodsport, WA 98548
(360) 877-9512
Mr. McKay, as owner of the completed commercial properties, and subsequent owners will be
responsible for operation and maintenance of the stormwater management features.
The retention ponds, gutters and downspouts, downspout piping&splash pads and graveled areas
should be inspected at a minimum twice each year(in the Fall before the wet season and in the
Spring after the wet season), and after any major storm event(more than an inch of precipitation in
a 24 hour period).
An Operation and Maintenance Covenant will be implemented as required by the County's
adopted requirements.
Minimum Requirement#11:Financial Liability. Performance bonding, or other appropriate
instruments shall be required for all projects to ensure compliance with these standards.
The proposed McKay development is a relatively modest development proposal and the O&M
Covenant is expected to satisfy this requirement.
Variances from these Standards. Variances from these standards may be allowed at the
discretion of the director or designee provided that the proponent will substantially meet flow control
and water quality goals established by or implicit in these standards.
No variances are deemed necessary from the current County Stormwater Management Ordinance
requirements.
This Stormwater Site Plan and supporting documents have been prepared by myself or under my
direct supervision as required under the Stormwater Management Ordinance requirements. I hope
this document and supporting elements meet the standards and needs of Mason County and the
McKays in permitting and developing their property as they currently intend.
Sincerely,
Alan A. Tahja, P.E. v��o w s
Attached: Stormwater Site Plan Sheets
O&M Covenant
StormShed2G Modeling Printouts 30ryg4
��`slONAL
File:C:ProjectsIMcKayWP 7 of 7 10/13/2008
Pr perty Line —220' <
r—— ——Vegetated Buffer —— —
�� 4 012-21-00003 1.27 cres I N
Buffer Planting Schedule: ry / �/ Z „ 30 I oo
Quantities per 100 feet N I I--
(Doubled to reduce buffer to 50%) t I tr; W E o
6 Canopy Trees
12 Understory Plants �I i d N b'
18 Shrubs / 30'Gate 1E -E e
S N
�0 I 12 i0 IJc10 12x O I i y Ir
a.
I Prope y Line 2 6.88, 1
Po Floor 120' Po Floor 60'x 8' —J
P nd Top 132'x 20' — Pond Tc 72'x 20' IIc�yy b
1 2:1 RV)Sidulopcs, 0 w O
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Property Line --310'
3D7 g 4 w� / Pond Top Dimensions 16'x 282' (2:1 SS) > W Ln b b
CISTER�9 b 4'x 270'x 3'Deep Retent on Pond Q I O (D O y O
ONAL EZ�l 0
UConjectural Storage Buildings: 3cw I e
/ Bldg A 8,500 Sqr Ft �,, e
,\ a� Bldg B 9,240 Sqr Ft W I la
Bldg C 8,550 Sqr Ft I N
Bldg D 9,120 Sqr Ft
Total—h 36,150 S r Ft q
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SCALE. t"= gwood t
100' S�0 I prin
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PAR2008-00039
Disperse downspout discharge into vegetated buffer ;y
Property Line —220' by way of buried 6"PVC transport pipe&dispersion pad. <
/ la
�------ --------------
pF NA$y / / 20' 00003 ——————-1 10'Vegetated Buffer
4' �ti� I.1Fa (� // 20' 1 Lines(Dashed)
/ iwn mxw ..
Pond Notes:
h I The pond designed for Prcl.No. o °n
Ao� � 30784�9 w� / N /
c ° ° 1 42012-21-90003(Floor Area= 1440 SF) N
'GISTS �� ,� 1 will accomodate a total building area
SSIDNAL ECG / c a up to 19,200 SF
/ 30'Gate A I The pond igned for Parcl.No. Sb°
? 15 1 10 42012-21-900 (Floor Area= 1080 SF) b
o (� 12n O I will accomodate a al building area 1'D
Conjectural Storage Buil ngs:
up to 20,000 SF
Bldg A 8,500 S r Ft ro I N w x-019
o O
Bldg B 9,240 qr Ft
Bldg C 8,550 qr Ft 65' j " 141
w
I Ix30 IT!'pinl ScpnUon fAme�) 1 O
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Bldg D 9,12 Sqr F 25' 10. Security Fenced N
Pro erty Line 246.88' 21' 1 Property Boundaries
Total-- 36,15 Sqr t I
10'
I —— 10' I
II I 00004 " Connecting Driveway —,< o
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Plastic or Metal Pipe I SCALE: 1"=60'
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/ 17" C7 c7 v°z a.. 3M o j Direct Gutter Downspouts
v L 15, into 6"Diameter solid PVC
— ------------------- dischar m to Rock
-------- pipes g s I
y° ------- Armored Dispersion Pads
/ ropert y (F thick)located at discharge I w to
.�
end of pipe near retention
pond floor bottom.
0
SCALE: V
0 I 2 3 4 feet a�i on
? 20'Top Pond Dimension >
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Ground Surrounding w m 3'Pond Depth(Inc.. 1'Freeboard) w Surrounding y
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---- - - ------------------------------ la b
--------- ----------------- N
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,a S�OQCS lssl r
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_ 2Yr_ �115 W
24 Hour Storm Event --
Peak Water Elevations 8' Wide Pond Floor
b
Pond Notes: Pond Notes: R
The pond designed for Prcl.No. i o Pond slopes and pond floor below
42012-21-90003 will accomodate V 1 0 y
1 rn the 2 Year 24 Hour Storm Event
S total building area up to 19,200 elevation(s)should be planted with o O
q oo water tolerant vegetaion. �- Q7
0
oc y�
The pond designed for Parcl.No. o rn 14
Silt shall be removed from pond 1,4
w`p,
42012-21-90004 will accomodate m a floors if and when the ponds do not `^b Q
a total building are up to 20,000 infiltrate/function as designed. N Y tr1
Sqr Ft. Parcel No. 42012-21-90003 8' x 180'x 3'Deep Retention Pond00
e
0
SCALE: V=4' Chain Link
ARM
0 1 2 3 4 feet
Security Fence (�
16'Top Pond Dimension 2
Surrounding
Ground Surrounding b y p
--------- Ground cV,t yr b
100 Yr es lssl . vg
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Buffer Planting Schedule: 10 Yr �ls y�of WA r
Quantities per 100 feet 2 Yr ,< , tTI
(Doubled to reduce buffer to 50%)
6 Canopy Trees 4' Wide Pond Floor co
12 Understory Plants 3'Pond Depth
18 Shrubs (Incl. F Freeboard)
30784 to
Parcel No.42012-21-90004 4'x 290'x 3' Deep Retention Pond
RETURN ADDRESS GRANTOR(S)(Last,First,Middle Initial)
Dwigj2t S.McKay McKay,Dwight S.
590 Elsland Lake Drive
Shelton, WA 98584-7821 GRANTEE; MASON COUNTY
DEPARTMENT OF PUBLIC WORKS
DECLARATION OF COVENANTS ASSOCIATED WITH
PRIVATELY MAINTAINED STORM DRAINAGE FACILITIES
Declaration of Covenant
In consideration of approval of the development known as
Shelton Springs Road Mini Storage Shelton WA 98584 relating to real property legally
described as follows: Lot 3 of SP#2413
County Assessor's Property Tax Parcel Number 42012-21-90003
The undersigned,as owner(s),covenant and agree that:
1. If at any time Mason County reasonably determines that maintenance or repair work is
required to be done to the existing, approved storm drainage facilities installed on the property
described above and located outside of any public right-of-way(which will mean repair and or clean
out of the existing system only to the same standards as originally installed and approved), the
Director of the Department of Public Works shall give the current owners seven days notice that the
County intends to perform such maintenance or repairs,or to have them performed by others.
If the current owners have not completed or are not diligently pursuing the repair or
maintenance of the system and it becomes necessary for Mason County to perform the work, the
current owners will assume responsibility for the cost of such maintenance or repair and will
reimburse the County within thirty days of receipt of the invoice. Overdue payments will require
payment of interest at the current legal rate for liquidated judgments, and any costs or fees incurred
by the County, should any legal action be required to collect such payments, will be borne by the
parties responsible for said reimbursements.
2. If at an time Mason Coun reasonably determines that
Y tv y t the existing and approved stone
drainage system on the property poses a hazard to life and limb,or endangers property,or adversely
affects the safety and operations of a public way, due to failure, damage or non-maintenance of the
existing on-site storm system,and that the situation is so adverse as to preclude written notice to said
owners, the Director of the Department of Public Works may take the measures necessary to
eliminate the hazardous situation(which will mean repair or clean out of the existing system only to
the same standards as originally installed and approved) provided the Director has first made a
reasonable effort to locate said owner before acting.
g
RETURN ADDRESS GRANTOR(S)(Last,First,Middle Initial)
Dwight S.McKay McKay,Dwight S.
590 EIsland Lake Drive
Shelton, WA 98584-7821 GRANTEE; MASON COUNTY
DEPARTMENT OF PUBLIC WORKS
DECLARATION OF COVENANTS ASSOCIATED WITH
PRIVATELY MAINTAINED STORM DRAINAGE FACILITIES
Declaration of Covenant
In consideration of approval of the development known as
Shelton Springs Road Mini Storage Shelton WA 98584 relating to real property legally
described as follows: Lot 4 of SP#2413
County Assessor's Property Tax Parcel Number 42012-21-90004
The undersigned,as owner(s),covenant and agree that:
1. If at any time Mason County reasonably determines that maintenance or repair work is
required to be done to the existing, approved storm drainage facilities installed on the property
described above and located outside of any public right-of-way(which will mean repair and or clean
out of the existing system only to the same standards as originally installed and approved), the
Director of the Department of Public Works shall give the current owners seven days notice that the
County intends to perform such maintenance or repairs,or to have them performed by others.
If the current owners have not completed or are not diligently pursuing the repair or
maintenance of the system and it becomes necessary for Mason County to perform the work, the
current owners will assume responsibility for the cost of such maintenance or repair and will
reimburse the County within thirty days of receipt of the invoice. Overdue payments will require
payment of interest at the current legal rate for liquidated judgments, and any costs or fees incurred
by the County, should any legal action be required to collect such payments, will be borne by the
parties responsible for said reimbursements.
2. If at any time Mason County reasonably determines that the existing and approved storm
drainage system on the property poses a hazard to life and limb,or endangers property,or adversely
affects the safety and operations of a public way,due to failure, damage or non-maintenance of the
existing on-site storm system,and that.the situation is so adverse as to preclude written notice to said
owners, the Director of the Department of Public Works may take the measures necessary to
eliminate the hazardous situation(which will mean repair or clean out of the existing system only to
the same standards as originally installed and approved) provided the Director has first made a
reasonable effort to locate said owner before acting.
it
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TAHJA ENGINEERING, Inc.
PO Box 235, Hoodsport, WA 98548
(360) 877-9512
Dwight S. McKay
590 E Island Lake Drive
Shelton, WA 98584
(360) 426-5975
StormShed Modeling Parcel No. 42012-21-90003.
LPOOLCOMPUTE [Retention Pond] SUMMARY using Puls
Start of live storage: 270.0000 ft
Event ;Match Q (cfs)jPeak Q (cfs)!Peak Stg(ft) Vol(co Vol(acft) !Time to Empty
6 month 0.0039 _ 0.3401 I 270.0964 1142.45 FO.0033 1 24.67
2 year 0.0309 0.4284 270.4834 1785.12 0.0180 24.83
10 year 0.0665 0.5321 271.0000 1821.33 0.0418 24.83
r100 year 0.2725 0.7569 272.0840 4682.63 0.1075 24.83
Summary Report of all Detention Pond Data
Event IiPrecip (in)
6 month 12.9000
2 year ;4.5000
F,0 year 1.6.00 0
100 year 19.0000
BASLIST2
[Un-03] Using [TYPE 1 A] As [6 month]
[Dev-03] Using [TYPEIA] As [6 month]
[Un-03] Using [TYPE 1 A] As [2 year]
[Dev-03] Using [TYPE 1 A] As [2 year]
[Un-03] Using [TYPE IA] As [10 year]
[Dev-03] Using [TYPE 1 A] As [10 year]
[Un-03] Using [TYPE 1 A] As [100 year]
[Dev-03] Using [TYPE 1 A] As [100 year]
LSTEND
Peak Q Peak T Peak Vol Area _
BasinID` Event Method/Loss(cfs) (hrs) (ac-cf) ac Raintype
( )
Un-03 I month 0.0039 24.00 0.0009 1.28 SBUH/SCS !TYPE 1 A
[Dev-03 6 0.3596 8 0000 0. 831 0 1.28 FBUH/SCS TYPEIA
; month
Un-03 j 2 year 0.0309 24.00 0.0271 1.28 1 SBUH/SCS I TYPE 1 A
File:C:WrojectslMcKay StrmShed Prc13 Basin Printout 1 of 3 10/13/2008
TAHJA ENGINEERING, Inc.
PO Box 235, Hoodsport, WA 98548
(360) 877-9512
Dev-0 0.8181 7.83 0.2803_[ 1.28 SBUH/SCS TYPE 1 A
3 2 e j
Un-03 i 10 yeaz 0. 60 65 17.00 0.0775 1.28 ; SBUH/SCS ;TYPElA
Dev-03 10 yeaz (`1_3013 7.83 0.4242 1.28 SBUWSCS ;TYPElA
�-
Un-03 y� 0.2725 8.17 0.2294 1.28 , SBUH/SCS 1TYPEIA
F
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I
Dev-03 j yea0r 2.3065 7.83 0.7256 1.28 ( SBUH/SCS 'TYPElA
BASLIST [TYPElA] AS [6 month] DETAILED [Un-03] [Dev-03] LSTEND
Record Id: Un-03
Design Method r SBlm Fi ainfall type F TYPElA
Hyd Into 10.00 min Peaking Factor 1 484.00
-
Abstraction Coeff F 0.20
Pervious Area(AMC 1) 1.28 ac JDCIA _ -F-0.00 ac
Pervious CN j 43.82 DC CN - �0.00 1
Pervious TC 15.88 min DC TC 0.00 min
Pervious CN Calc I
j - Description - _ SubArea Sub cn
Meadow or Pasture 1.28 ac j 65.00
Pervious Composited CN(AMC 2) 65.00 j
- - -- -
Pervious TC Calc
'Type Description Length Slope Coeff Misc TT
Sheet Short prairie grass and lawns.:0.15 320.00 ft 4.00% 0.1500 4.50 in 15 88 min
F F I
Pervious TC 15.88 min
-- - - ----
Record Id: Dev-03
Design Method SBUH Rainfall type ` TYPE I A "
Hyd Intv r 10.00 min jPeaking Factor i� 484.00 I
j Abstraction Coeff 0.20
Pervious Area (AMC 1) 1.28 ac DCIA [- 0.00 ac
Pervious CN
r 81.89 i �-- -DC CN 0.00
Pervious TC 1.96 min DC TC [-0.00 min '
Pervious CN Calc
File:C:IProjectslMcKay StrmShed Prc13 Basin Printout 2 of 3 10/13/2008
i i
TAHJA ENGINEERING, Inc.
PO Box 235, Hoodsport, WA 98548
(360) 877-9512
Description SubArea Sub cn
Gravel Roads &Parking Lots 0.64 ac F 76.00
Impervious surfaces (pavements,roofs, etc) 0.49 ac F 98.00
Open spaces, lawns,parks(50-75%grass) , 0.15 ac 77.00
Pervious Composited CN(AMC 2) F 84.54
Pervious TC Cale
FType F Description Length Slope ( Coeff Misc TT
_
ISheet Smooth Surfaces.: 0.011 320.00 ft 4.00% r.0110 4.50 in 1.96 min
i
Pervious TC 1.96 min
HYDLIST SUMMARY [6 month out] [2 year out] [10 year out] [100 year out]
LSTEND
[
H dID Peak cfs y - Q ( )jPeak T(hrs)jPeak Vol(ac ft)lCont Area (ac)
6 month out 0.3401 8.00 F 0.1380 1.2800
2 year out 0.4284 8.33 0.2802 1.2800
10 year out 0.5321 8.67 0.4242 1.2800
100 year out 0.7569 9.00 F 0.7256 1.2800
STORLIST [Pond 1] LSTEND
Record Id: Pond 1
Descrip: Mention Pond Increment 0.10 ft y� w
Start El. 1270.0000 ft Max El. 273.0000 ft �`� o
Length 180.0000 ft W .0000 ft
Width 8 `per
Length ssl 2.00h:1 v Length ss2 2.000Oh:1 v .q
PO +4 �
rWidth ssl 12 OOh:ly Width ss2 (2.00 0 lv 784
��ISTER`�
�s`sjONAL
DISCHLIST [Infiltration] LSTEND
Record Id: Infiltration
Descrip: Orototype Structure lincrement 0.10 ft
Start El. '270.0000 ft IMax El. 1105.0000 ft'
�` r
Infiltration rate 10.0000 in/hr I W r Multiplier j 1.00
Licensed to: TAHJA ENGINEERING. Inc.
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File:C:IProjectsIMcKayStrmShedPrcl3Basin Printout 3 of 3 10/13/2008
TAHJA ENGINEERING, Inc.
PO Box 235, Hoodsport, WA 98548
(360) 877-9512
Dwight S. McKay
590 E Island Lake Drive
Shelton, WA 98584
(360) 426-5975
StormShed Modeling Parcel No. 42012-21-90004
LPOOLCOMPUTE [Retention Pond] SUMMARY using Puls
Start of live storage: 260.0000 ft
Event ;Match Q (cfs) Peak Q (cfs);Peak Stg(ft) Vol(cf) �ol(acft) Time to Empty
6 month 0040 ( 0.2889 j 260.1369 159.45 0.0037 24.67
2 year ; 0.0316 0.4232 260.6053 856.03 0.0197 j 24.67
10 year ! 0.0680 F 0.5673 ! 261.1010 1860.64 0.0427 24.83
100 year; 0.2789 0.8463 262.0415 4535.40 0.1041 24.83
Summary Report of all Detention Pond Data
Event Precip (in)
�6 month '2.9000
2 year '4.5000
10 year j6.0000
100 year'9.0000
BASLIST2
[Un-04] Using [TYPE IA] As [6 month]
[D-04] Using [TYPE 1 A] As [6 month]
[Un-04] Using [TYPE 1 A] As [2 year]
[D-04] Using [TYPE 1 A] As [2 year]
[Un-04] Using [TYPE 1 A] As [10 year]
[D-04] Using [TYPE IA] As [10 year]
[Un-04] Using [TYPE 1 A] As [100 year]
[D-04] Using [TYPE 1 A] As [100 year]
LSTEND
Peak Q Peak T Peak Vol Area
BasinID Method/Loss lRaintype Event (cfs) (hrs) (ac-cf) (ac)�
6
UI1-04 month 0.0040 24.00 0.0009 1.31 SBUH/SCS jTYPE IA
r 6
4
[D-04 0.3547 8.00 F 0.1377 1.31 I SBUH/SCS ITYPEIA
i
month
Un-04 2 year 0.0316 F 24.00 F 0.0277 F1.31 SBUH/SCS ;TYPE 1 A
D-04 2 year 0.8164 7.83 0.2818 1.31 FSBUH/SCS ;TYPEIA
File:C:IProjectslMcKayStrmShed Prcl4 Bann Printout 1 Of 3 10/13/2008
II
TAHJA ENGINEERING, Inc.
PO Box 235, Hoodsport, WA 98548
(360) 877-9512
Un-04 ' 10 year 0.0680 17.00 �0.0793 1.31 SBUH/SCS YPT EIA
D-04 10 year 1.3078 7.83 0.4283 F1.31 FSBUH/SCS TYPElA
Un-04 ar
y� 0.2789 8.17 0.2348 1.31 [SBUH/SCS jTYPEIA j
-- - -
[D-04- 100 2.3343 7.83 f`0.7357 I 1.31 I SBUH/SCS TYPEIA
w ;
Ye I
BASLIST [TYPEIA] AS [6 month] DETAILED [Un-04] [D-04] LSTEND
Record Id: Un-04
Design Method SBUH Rainfall type TYPE IA
- -- _�
Hyd Intv j 10.00 min Peaking Factor 484.00
----- __ V
Abstraction Coeff 0.20
Pervious Area (AMC 1) 1.31 ac DCIA 0.00 ac
Pervious CN �� 43.82 DC CN �0.00
Pervious TC 15.88 min iDC TC 0 00 min 1
Pervious CN Calc
Description SubArea Sub cn
Meadow or Pasture F-- 1.31 ac 65.00
' Pervious Composited CN(AMC 2) 65.00
j - - Pervious TC Calc
j Type �- Description ' Length i Slope CoeffF TT j
'Sheet 'Short prairie grass and lawns.: 0.15 F320.00 ft 4.00% 0.1500 j4.50 in 15.88 min
Pervious TC 15.88 min j
Record Id: D-04
Design Method SBUH Rainfall type TYPEIA
H d Inty 10.00 min Peaking Factor 484.00
Abstraction Coeff 0.20
Pervious Area (AMC 1)� j 1.31 ac DCIA 0.00 ac
Pervious CN T 81.37 DC CN j 0.00
Pervious TC 1.96 min JDC TC 0.00 min
Pervious CN Calc
Description SubArea Sub cn
File:C:IProjectslMcKayStrmShed Prcl4 Basin Printout 2 of 3 10/13/2008
II
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j
TAHJA ENGINEERING, Inc.
PO Box 235, Hoodsport, WA 98548
(360) 877-9512
- Gravel Roads &Parking Lots 0.64 ac 76.00
Impervious surfaces(pavements,roofs, etc) 0.51 ac 98.00
Open spaces, lawns,parks (<50% grass) 0.16 ac 68.00
Pervious Composited CN(AMC 2) 83.59
- Pervious TC Calc
Type Description Length i Slope C eo f Misc TT
Sheet Smooth Surfaces.: 0.011 '320.00 ft 4.00% {0.0110 4.50 in 1.96 min
Pervious TC 1.96 min
HYDLIST SUMMARY [6 month out] [2 year out] [10 year out] [100 year out]
LSTEND
HydID 'Peak fs)jPeak T (hrs)jPeak Vol(ac-ft) Cont Area (ac)
6 month out 0.2889 1 8.17 0.1377 1.3100
12 year out 0.4232 1 8.33 1 0.2818 F-1.3100
10 year out 5673 F 8.67 0.4283 1.3100
100 year out'l 0.8463 8.67 0.7357 1.3100
STORLIST [Pond 1] LSTEND
Record Id: Pond 1
�Descrip: [etention Pond(Increment 0.10 ft _! �,� A ?'
WA
Start El. 260.0000 ft Max El. 263.0000 ft 1y��
Length 270. 0000 ft Width 4.0000 ft ao
Length ss 1 2.00h:1 v Length ss2 2.0000h:1 v
Width ssl 2.00h:ly Width ss2 2.0000h:lv 1.6 30784
CISTt
_ o��s`SIONAL
DISCHLIST [Infiltration] LSTEND
Record Id: Infiltration
IDescrip: Trototype Structure lIncrement 10.10 ft
Start El. 1260.0000 ft Max El. 1265. 00 00 ft
Infiltration rate F 10 0000 in/hr WP Multiplier 1.00
Licensed to: TAHJA ENGINEERING. Inc.
File:C:IProjectslMcKay StrmShed Prcl 4 Basin Printout 3 of 3 10/13/2008
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