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RVICES, PLLC
47151421/ Place SW #B_ Edmonds, WA M026
FurrEngineering@gmail.com
RECEIVED
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CITY OF EDMONDS
DEVELOPMENT SERVICES
DEPARTMENT
BLD2021-1482
Technical Information Report
BURDETT SINGLE FAMILY RESIDENCE
Edmonds, Washington — King County
Parcel # 27032300100900
332 Sunset Ave.
Edmonds, WA 98020
For: Chris and Lisa Burdett
November 01, 2021
Revised:
Prepared by: Dean A. Furr, P.E.
FES Project #21073
REVIEWED
BY
CITY OF EDMONDS
1
www.furrenciineering.com
Table of Contents
1.0 PROJECT OVERVIEW..........................................................................................1
2.0 CONDITIONS AND REQUIREMENTS SUMMARY................................................2
Analysis of the (9) MINIMUM REQUIREMENTS/ADDITIONAL LID
REQUIREMENTS.................................................................................................2
AdditionalRequirements.......................................................................................4
3.0 OFF -SITE ANALYSIS............................................................................................ 5
DEFINE AND MAP THE STUDY AREA................................................................5
RESOURCE REVIEW...........................................................................................7
PugetSound......................................................................................................... 7
No mapped floodplains exist on site......................................................................7
FieldInspection.....................................................................................................8
Drainage System Description and Problem Description........................................8
4.0 STORMWATER ANALYSIS AND DESIGN.........................................................10
ExistingSite Hydrology.......................................................................................10
Developed Site Hydrology...................................................................................10
On-Site................................................................................................................10
Off -Site (Frontage Improvements are not required).............................................11
WaterQuality......................................................................................................11
Emergency Overflow...........................................................................................11
FloodPlain..........................................................................................................12
DIRECT DISCHARGE ANALYSIS......................................................................12
5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN...........................................18
6.0 SPECIAL REPORTS AND STUDIES...................................................................19
7.0 OTHER PERMITS................................................................................................20
8.0 ESC ANALYSIS AND DESIGN............................................................................21
9.0 BOND QUANTITIES............................................................................................22
10.0 OPERATIONS AND MAINTENANCE MANUAL..................................................23
Page i
1.0 PROJECT OVERVIEW
The Burdett SFR is in Edmonds, Washington. The site is bound by urban
residential homes to the north, south, east and west by Sunset Avenue North.
More generally, the site is located within the SE 1/4 of the NE 1/4, Section 23,
Township 27 North Range 3 East WM. The project area consists of a single parcel
#27032300100900, 332 Sunset Ave. N and approximately 0.27ac in size. The site
has an existing single family, detached garage and ADU. The site currently takes
access from Sunset Ave. N and the alley to the south. The site slopes to the W at
approximately 3% and is covered mostly by impervious surface (roof and paving).
The project proposes to construct a new 2-story single family residence and
attached garage. The primary vehicle access will be from the alley, while a single
on -site parking stall will be from the existing driveway cut in Sunset Ave. N.
Additionally, there will be access from 2nd Ave N. for emergency only. Typical urban
Landscaping and screening is proposed.
This area per NRCS Soil survey classifies this area as Alderwood-Urban land
complex, 2-8 percent, hydrologic soil group "B" (moderately well drained).
The project is subject to Category 2 Stormwater Site Plans and is required to utilize
on -site stormwater management techniques to the maximum extent feasible. The
project proposes to connect to the existing storm system within Sunset Ave. N.
where it "DIRECT DISCHARGE" into the Puget Sound. The facility will be sized to
Flow Control Duration Standard — Matching Forested Conditions using WWHM
2012 in accordance with the 2014 Department of Ecology Stormwater
Management Manual of Western Washington (SWMMWW) and the 2017 City of
Edmonds Stormwater Addendum.
Page 1
2.0 CONDITIONS AND REQUIREMENTS SUMMARY
Hearing Examiners TBD
Analysis of the (9) MINIMUM REQUIREMENTS/ADDITIONAL LID REQUIREMENTS
MR #1. Preparation of Stormwater Site Plans
This report will serve as the Stormwater Site Plan, prepared per City code and the
SMMWW.
MR #2. Construction Stormwater Pollution Prevention
Construction Stormwater Pollution Prevention Plans are prepared per the SMMWW to
address the 13 elements. A SWPPP will be provided as a separate document for
approval.
MR #3. Source Control of Pollution
Source Control methods for commercial projects are used. Common Source Control
methods for construction are also used during the construction period.
MR #4. Preservation of Natural Drainage Systems and Outfalls
The site is slopes to the southwest corner. After development the existing drainage pattern
will remain unchanged, but the project will not add or increase runoff due to 100%
INFILTRATION of onsite developed impervious.
MR #5. On -site Stormwater Management/LID
Flow control BMPS, such as post construction soil amendment will be used for On -site
Stormwater Management. Infiltration will be proposed per the Geotech report.
See the following
List #2: On -site Stormwater Management BMPs for Projects Triggering Minimum
Requirements #1 through #9
For each surface, consider the BMPs in the order listed for that type of surface. Use the
first BMP that is considered feasible. No other Onsite Stormwater Management BMP is
necessary for that surface. Feasibility shall be determined by evaluation against:
• Design criteria, limitations, and infeasibility criteria identified for each BMP in the
SMMWW, and
• Competing Needs Criteria listed.
• See also Volume III, Appendix III-D for a summary of infeasibility criteria for all
BMP's
• The City of Edmonds allows bypass up to 1,OOOsf MAX, only after demonstrating
that collection of these areas is infeasible.
I. Lawn and landscaped areas:
1. Post -Construction Soil Quality and Depth BMP T5.13 on Pg. 911;
This BMP will be implemented to the maximum extent feasible. See the plan
for this BMP location and option.
II. Roofs:
1. Full Dispersion (65/10) BMP T5.30 on Pg. 939, or Downspout Full Infiltration
Systems BMP T5.10A on Pg. 905;
Page 2
Downspout Full Infiltration systems BMP T5.10A will be implemented ON
ALL ROOF SURFACES.
No other BMP's for roof run off will be evaluated.
2. Bioretention BMP T7.30 on Pg. 959, must have a minimum horizontally projected
surface area below the overflow which is at least 5 percent of the total surface
are draining to it;
This BMP is NOT proposed.
3. Downspout Dispersion systems BMP T5.10B on Pg. 905;
Roof downspout dispersion is NOT proposed. Because of the unavailable
flow path required for this BMP to perform adequately.
4. Perforated Stub -out Connections BMP T5.10C on Pg. 905;
This BMP is proposed.
III. Other Hard Surfaces:
The project proposes to mitigate stormwater run-off from the PARKING
LOT/HARDSCAPES conveying stormwater to the proposed DRYWELL.
1. Full Dispersion (65/10) BMP T5.30 in accordance with Volume VI Section 2.3, or
Downspout Full Infiltration Systems BMP in accordance with Volume III, Section
3.9.3.
The project is unable to protect and maintain 65% or more of the site for
the Full Dispersion BMP T5.03.
2. Permeable pavement BMP T5.15 in accordance with Volume III, Section 3.5.
This BMP T5.15 is NOT proposed.
3. Bioretention BMP T7.30 on Pg. 959, must have a minimum horizontally projected
surface area below the overflow which is at least 5 percent of the total surface
are draining to it;
This BMP T7.30 is proposed to mitigate a portion of the 1001 Ave. W.
sidewalk in right of way.
4. Sheet Flow Dispersion BMP T5.12 on Pg. 908 or Concentrated Flow Dispersion
BMP on Pg. 905
Dispersion is NOT proposed because of the unavailable flow path required
for this BMP T5.12 to perform adequately.
MR #6. Runoff Treatment
The project PGHS, 2,285sf is LESS than the 5,OOOsf threshold, therefore, run off
treatment is NOT REQUIRED. Additionally, an on -site catch basin will be fitted with a
floatable containment structure. The roof will be coated to eliminate pollutants entering
the drainage system.
MR #7. Flow Control
Page 3
The project has a total (ON+OFF-SITE) impervious area of 7,072sf < 10,000 sf threshold,
therefore flow control per MR #7 is NOT REQUIRED. We propose to DIRECT
DISCHARGE into the storm system that is hydraulically connected to the Puget Sound.
See section 4 of the drainage report for clarification of flow control, calculations, and
analysis.
MR #8. Wetlands Protection
There are no wetlands on the site or nearby the site.
MR #9. Operation and Maintenance
Operation and Maintenance of the storm drainage system for this project will be provided
in Section 10.
Stormwater conveyance will be analyzed in Section 5 of this report
Financial Liability
A bond quantities worksheet for construction and landscaping will be provided.
Additional Requirements
Protection of LID Facilities durinq and after construction
Areas identified for LID (infiltration/bioretention) shall be shown of the TESC
plan and protected by fencing.
Construction in these areas shall be limited to light duty vehicles and/or hand
work.
After construction, surficial LID BMP's (bioretention/raingardens) shall remain
protected until site is full stabilized.
Downstream Analysis
This Category 2 Project will identify off -site impacts of stormwater
(conveyance capacity, flooding, erosion (stream bank), through site visit and
resource review.
Propose mitigation measures when stormwater issues are identified.
Page 4
3.0 OFF -SITE ANALYSIS
DEFINE AND MAP THE STUDY AREA
Th offsite Analysis was prepared in accordance with Section 6.2.2 "Additional
Requirements", of the 2017 City of Edmonds Stormwater Addendum. The site is
located at 332 Sunset Ave N., Edmonds.
See Figure 1 and Figure 2 for maps of the study area
}
Figure 1: City of Edmonds GIS Vicinity Map
Page 5
Figure 2: City of Edmonds GIS TOPOGRAPHY
Page 6
RESOURCE REVIEW
Adopted Basin Plans:
Puget Sound
Floodplan/Floodway (FEMA) Map
No mapped floodplains exist on site.
City of Edmonds GIS
Critical Areas
o Landslide and Erosion Layers shows a "very" small Erosion Hazard Area
(15%-40%). No other landslide or erosion hazards adjacent to the site.
4
1
o A small portion of the seismic hazard area is on the west edge of the site.
Page 7
o The floodplain is west of the site.
o review of the remaining sublayers (i.e. creeks, earth subsidence, etc.)
shows no additional critical areas on or adjacent to the site.
Field Inspection
Date: May 10, 2021
Time: 3:30pm
Weather Observation: partly sunny, 65°F, 10mph wind in a NW direction
24-hour precipitation: 0.05 inches (wunderground website)
Monthly Precipitation: 1.23 inches (wunderground website)
A field investigation was performed by Dean A. Furr, P.E. of Furr Engineering
Services to determine the existing upstream and downstream storm drainage
patterns.
Drainage System Description and Problem Description
Upstream
There is no significant upstream run-on from the adjacent single family residences.
Downstream
Stormwater sheet flows toward Sunset Ave N. and flows north west along the curb
for approximately 165'. Stormwater enters the catch basin and flows through an
12" pipe "offsite" to a discharge point within BNSF right-of-way and discharges into
the Puget Sound approximately 250ft downstream of the project site.
See the exhibit on the following page.
Page 8
PD 7-55
/ r r
r
Page 9
4.0 STORMWATER ANALYSIS AND DESIGN
The project is subject to Category 2 Stormwater Site Plans and is required to utilize
on -site stormwater management techniques to the maximum extent feasible. The
facility will be sized to Flow Control Duration Standard — Matching Forested
Conditions using WWHM 2012 in accordance with the 2014 Department of
Ecology Stormwater Management Manual of Western Washington (SWMMWW)
and the 2017 City of Edmonds Stormwater Addendum.
Existing Site Hydrology
The Burdett SFR is in Edmonds, Washington. The site is bound by urban
residential homes to the north, south, east and west by Sunset Avenue North.
More generally, the site is located within the SE 1/4 of the NE 1/4, Section 23,
Township 27 North Range 3 East WM. The project area consists of a single parcel
#27032300100900, 332 Sunset Ave. N and approximately 0.29ac in size. The site
has an existing single family, detached garage and shed. The site currently takes
access from Sunset Ave. N and the alley to the south. The site slopes to the W at
approximately 3% and is covered mostly by impervious surface (roof and paving).
This area per NRCS Soil survey classifies this area as Alderwood-Urban land
complex, 2-8 percent, hydrologic soil group "B" (moderately well drained).
See the following existing conditions area breakdown table, and the Existing
Conditions Exhibit at the end of this section.
EXISTING CONDITIONS
Sf
ac
PARCEL AREA
12,724.00
0.29
DISTURBED AREA ON -SITE
12,524.00
0.29
DISTURBED AREA (OFF -SITE)
258
0.01
IMPERVIOUS
6,754
0.16
HOUSE
1,721
0.04
GARAGE
616
0.01
SHED
561
0.01
DRIVEWAY
3857
0.09
PERVIOUS (LS)
5,970
0.14
Table 1: Existing Conditions area breakdown
Developed Site Hydrology
On -Site
The project proposes to construct a new 2-story single family residence and
attached garage. The primary vehicle access will be from the alley, while a single
on -site parking stall will be from the existing driveway cut in Sunset Ave. N. The
access from 2nd Ave N. will be emergency only. Typical urban Landscaping and
screening is proposed.
Page 10
The following table shows the lot area breakdown.
PROPOSED DEVELOPED
sf
ac
DISTURBED AREA (ON -SITE)
12,524
0.29
IMPERVIOUS
7,894
0.181
HOUSE
4,776
0.11
DRIVEWAY (SOUTH) & EM. ACCESS
2,017
0.05
PARKING STALL
268
0.01
WATER FEATURE
84
0.00
PAVERS
749
0.02
PERVIOUS (LS)
4,630
0.106
DISTURBED AREA (OFF -SITE)
258
0.01
TRENCH PATCH (PAVING)
70
0.00
DRIVEWAY CUT (2ND Ave N)
188
0.00
IMPERVIOUS ON/OFF-SITE
7,964
0.18
Table 2: Developed On/Off-Site area break down
The project proposes to collect all on -site runoff in catch basins and convey it along
the south side of the proposed building and direct discharge to the existing storm
system within Sunset Ave. N. The project roof runoff will be collected to the roof
level between the main house and garage. Stormwater will cascade down a
concrete wall and enter a pond feature. The pond will be fitted with and overflow
that will be connected to the on -site conveyance system. Additionally, stormwater
will be conveyed through a perforated pipe connection BMP T5.10C before
discharging into the storm system within Sunset Ave. N.
Off -Site
The project proposes install a catch basin and pipe to connect to the existing storm
drainage system within Sunset Ave.. Additionally, a new driveway access will from
2nd Ave. N. See the table below for offsite breakdown.
PROP. OFF -SITE DEVELOPMENT
sf
ac
DISTURBED AREA (OFF -SITE)
258
0.00
TRENCH PATCH (PAVING)
70
0.00
DRIVEWAY CUT (2ND Ave N)
188
0.00
Table 3: Off -Site Area breakdown
Water Quality
The project PGHS, 2,285sf which is LESS than the 5,000sf threshold, therefore,
run off treatment is NOT REQUIRED. Additionally, a catch basin will be fitted with
a floatable separator. The roof will be coated to eliminate pollutants entering the
drainage system.
Emergency Overflow
Not required
Page 11
Flood Plain
Review of the City website GIS map shows that this property is outside of the 100-
year flood Zone.
DIRECT DISCHARGE ANALYSIS
The project to proposes to direct discharge into the existing drainage system.
First, it must be determined that the existing drainage system has capacity for the
additional runoff associated with the new development.
The existing drainage basin encompasses approximately 3.90ac shown in the
Basin Analysis Exhibit. Stormwater generally sheet flows to the west and enters
the catch basin within Sunset Ave N near the 342 Sunset Ave. N. address.
However, stormwater from the project site will be connected to an existing CB
with a solid lid within Sunset Ave N. It appears that stormwater from the Burdett
SFR project and the adjacent 340/336 Sunset Ave. residences are connected to
the same CB.
WWHM 2012 was used to determine the hydrology from the basin. See the
foIlowing table.
EXISTING BASIN
sf
ac
BASIN
171,115.81
3.93
LAND USE
sf
ac
IMPERVIOUS
119,781
2.75
PERVIOUS (A/B SOIL)
51,335
1.18
Table 4: WWHM input table
The followina shows the flow runoff from the basin
Return Period Flow(cfs)
25 Year = 1.7512
50 Year = 2.0130
100 Year = 2.2933
Analysis using Mannings equation
Q(full) = 1.49/n*A*R2/3*S1/2 =(1.49/0.012)(Ti/4*8)(0.5/2)2/3(0.006)1/2
for the 12", HDPE,153LF pipe has the capacity to convey
PIPE DATA
PIPE SIZE (IN)
12
PIPE MATERIAL
N12, SD
PIPE LENGTH (FT)
153
A UP TO DOWNSTREAM (FT)
30.17
SLOPE (FT/FT)
0.1972
QFULL (CFS)
17.19
It can be said that the pipe has a significant capacity to convey the runoff from
332, 340. 336 Sunset Ave N when the basins Q100basin=2.293cfs <<<
Q100pipe = 17.19cfs
Page 12
Additionally, the 12" CONC., 14LF pipe section that will convey the basin runoff is
PIPE DATA
PIPE SIZE (IN)
12
PIPE MATERIAL
Conc. (avg)
PIPE LENGTH (FT)
14
A UP TO DOWNSTREAM (FT)
2.7
SLOPE (FT/FT)
0.1929
QFULL (CFS)
15.69
It can be said that the pipe has a significant capacity to convey the runoff from
the basin Q100basin=2.293cfs <<< Q100 pipe = 15.69cfs
Page 13
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sf
ac
PARCELAREA
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0.29
DISTURBED AREA ON -SITE
12,524.00
0.29
DISTURBED AREA (OFF -SITE)
258
0.01
IMPERVIOUS
6,754
0.16
HOUSE
1,721
0.04
GARAGE
616
0.01
ADU
561
0.01
DRIVEWAY
3857
0.09
PERVIOUS (LS)
5,970
0.14
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Sf
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0.29
IMPERVIOUS
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0.181
HOUSE
4,776
0.11
DRIVEWAY (SOUTH) & EM. ACCESS
2,017
0.05
PARKING STALL
268
0.01
WATER FEATURE
84
0.00
PAVERS
749
0.02
PERVIOUS (LS)
4,630
0.106
DISTURBED AREA (OFF -SITE)
258
0.01
TRENCH PATCH (PAVING)
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188
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Sf
ac
REPLACED IMPERVIOUS
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0.00
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4,906
0.11
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0.07
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0.18
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Date:
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Project No:
BURDETT SFR
Reference Sheet:
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Drawing No:
141-F, 12" CONC. PIPE
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12" IN E 36.67
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EXISTING BASIN
sf
ac
BASIN
171,115.81
3.93
LAND USE
sf
ac
IMPERVIOUS
119,781
2.75
PERVIOUS (A/B SOIL)
51,335
1.18
Return Period Flow(cfs)
25 Year = 1.7512
50Year = 2.0130
100 Ye a r = 2.2933
PIPE DATA
PIPE SIZE (IN)
12
PIPE MATERIAL
N12, SD
PIPE LENGTH (FT)
153
0 UP TO DOWNSTREAM (FT)
30.17
SLOPE (FT/FT)
0.1972
QFULL (CFS)
17.19
PIPE DATA
PIPE SIZE (IN)
12
PIPE MATERIAL
Conc. (avg)
PIPE LENGTH (FT)
14
A UP TO DOWNSTREAM (FT)
2.7
SLOPE (FT/FT)
0.1929
QFULL (CFS)
15.69
T14
100 50 0 100 200
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5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN
The on -site conveyance system will be designed to convey the 25-year, 24-hour
and 100-year, 24-hour storm events. Using Mannings equation a 8-inch pipe at
0.6 percent slope has the capacity to convey 1.02 cfs.
Q(full) = 1.49/n*A*R2/3*S1/2 =(1.49/0.012)(7u/4*8)(0.5/2)2/3(0.006)1/2 =1.02 cfs.
The developed runoff from the on -site area (WWHM 2012)
Flow Frequency
Flow(cfs) 0801 15m
2 Year = 0.0517
5 Year = 0.0704
10 Year = 0.0842
25 Year = 0.1033
50 Year = 0.1188
100 Year = 0.1353
The pipe system has capacity since pipe capacity is 1.02cfs >> 0.135 cfs 100yr
run-off.
Page 18
6.0 SPECIAL REPORTS AND STUDIES
NA
Page 19
7.0 OTHER PERMITS
The following permits and/or approvals are thought to be required as part of this
project:
• Clearing and Grading Permit
• Right -Of -Way use Permit
• Land Use Permit
Page 20
8.0 ESC ANALYSIS AND DESIGN
TESC measures are put into place to prevent sediment from leaving the site. The
site is generally flat. The proposed TESC plan will include, but not be limited to,
the following guidelines set in the jurisdictions Minimum Requirement
"Construction Stormwater Pollution Prevention".
A SWPPP will be provided to address:
Clearing Limits — Clearing limits specify the boundary of the work to be done.
Clearing are defined on the TESC plans and will be flagged in the field.
2. Cover Measures — Cover measures are involved (typically) with the means
to control erosion of exposed soil and are specified on the TESC plans.
3. Perimeter Protection — Perimeter protection keeps site sediment from leaving
the construction site. This type of protection typically involves a silt fence.
The silt fence and clearing limits are shown on the TESC plans.
4. Traffic Area Stabilization — Traffic area stabilization is addressed by a
stabilized construction entrance.
5. Sediment Retention — Retention will be established by silt fences around the
perimeter and catch basin inserts that will control of the on -site sediment -
laden water.
6. Surface Water Collection — An interceptor ditch with check dams is shown in
the plans and will be implemented in the field if necessary.
7. Dewatering Control — Any water from dewatering shall be filtered or
contained so sediment can filter out prior to discharge downstream.
8. Dust Control — Dust control will be provided by sprinkling.
9. Wet Season Construction — Construction will be conducted according to the
jurisdiction's standards during the wet season.
10. Construction Within Sensitive Areas and Buffers - Any construction within the
wetland buffer will be subject to sensitive areas restrictions and is contained
in the TESC notes.
11. Maintenance — Maintenance requirements are detailed in the TESC notes
within the engineering plans.
12. Final Stabilization — Upon completion of the project, all disturbed areas will
be stabilized and Best Management Practices removed.
13. LID BMP's — Protect areas that will be designated as infiltration. Do not allow
turbid runoff to enter excavated infiltration facilities. If the soil porosity is
compromised, additional excavation is required to reach suitable soils.
Page 21
9.0 BOND QUANTITIES
NA
Page 22
10.0 OPERATIONS AND MAINTENANCE MANUAL
The perforated pipe connection and conveyance drainage facilities on this project
will be private facilities owned and maintained by the Owner.
See the following.
Page 23
Table-4.5.2(5) Maintenance Standards - Catch Basins
Results
Maintenance
Conditions When Maintenance is
Expected
Component
Defect
Needed
When Main-
tenance is
performed
No Trash or
debris loc-
Trash or debris which is located imme-
ated imme-
diately in front of the catch basin opening or
diately in
is blocking inletting capacity of the basin by
front of catch
more than 10%-
basin or on
Trash or debris (irk the basin) that exceeds
grate open-
60 percent of the sump depth as measured
i ng-
from the bottom of basin to invert of the low-
No trash or
est pipe into or out of the basin, but in no
debris in the
Trash &
case less than a minimum of six inches
catch basin -
Debris
clearance from the debris surface to the
invert of the lowest pi pe-
Inlet and out-
let pipes free
Trash or debris in any inlet or outlet pipe
of trash or
blocking more than 1/3 of its height.
debris.
General
Dead animals or vegetation that could gen-
No dead
erate odors that could cause complaints or
animals or
dangerous gases (e-g-, methane)-
vegetation
present
within the
catch basin.
Sed i me nt (i n the bas i n) that exceeds 60per
cent of the sump depth as measured from
the bottom of basin to invert of the lowest
pipe into oroutof the basin, but in no case
No sediment
Sediment
less than a minimum of6 inches clearance
in the catch
from the sediment surface to the invert of the
basin
lowest pipe -
Structure
Top slab has holes larger than 2 square
Top slab is
Damage to
inches or cracks wider than 1/4 inch. (Intent
free of holes
Frame and/or
is to make sure no material is running into
and cracks -
Top Slab
basin).
Frame is sit-
Table V-4.5.2(5) Maintenance Standards - Catch Basins (continued)
Results
Maintenance
Conditions When Maintenance is
Expected
Component
Defect
Needed
When Main-
tenance is
performed
Frame not sitting flush on top slab, i,e„ sep-
ting flush on
the
aration of more than /4 inch of the frame
riser rings
from the top slab. Frame not securely
or tap slab
attached
and firmly
attached,
Basin
Maintenance person judges that structure is
replaced or
unsound,
repaired to
Fractures or
design stand -
Cracks in
gout fillet has separated or cracked wider
ards.
Basin Walls}
than 1/2 inch and long erthan 1 foot at the
Bottom
joint of any inlet}outlet pipe or any evidence
Pipe is
of soil particles entering catch basin through
regrouted
cracks,
and secure at
basin wall,
Basin
Settlement}
if failure of basin has created a safety, fun
replaced or
Misalignment
tion, ordesign problem,
repaired to
design stand-
ards,
o veget-
Vegetation growing across and blocking
ation block -
more than 10% of the basin opening,
ing opening
to basin,
Vegetation
Vegetation growing in inleVoutlet pipe joints
that is more than six inches tall and less
No veget-
than six inches apart,
root
growth
row h
present,
Contamination
See Detention Ponds (No, 1),
No pollution
and Pollution
present,
Cover Not in
Cover is missing or only partially in place.
Catch basin
Catch Basin
Place
Any open catch basin requires main-
cover is
tenance.
closed
Cover
Locking ech-
Mechanism cannot be opened by one main-
Mechanism
anism Not
Itenance person with propertools. Bolts into
opens with
Table V-4. . ( ) Maintenance Standards - Catch Basins (continued)
Results
Maintenanr,e
Conditions When Maintenance is
Expected
Component
Defect
Needed
When Main-
tenance is
performed
Working
frame have less than 112 inch of thread.
proper tools.
One maintenance person cannot remove lid
Cover can be
Cover Difficult
after applying normal lifting pressure.
removed by
to Remove
(intent is keep cover from sealing off access
one main -
tenance ,per -
to maintenance.)
son.
Ladder meets
design stand
Ladder Rungs
Ladder is unsafe due to missing rungs, not
ards and
Ladder
Unsafe
securely attached to basin wall, mis-
allows main -
alignment, rust, cracks, or sharp edges.
to ance per-
son safe
access.
Grate open -
rate opening
Grate with opening wider than 718 inch,
ing meets
Unsafe
design stand-
ards.
Metal Grates
Trash and
Trash and debris that is blocking more than
rate free of
(if Applic-
Debris
20% of grate surface inletting capacity.
trash and
able)
debris.
Grate is in
Damaged or
Grate missing or broken members) of the
place and
Missing.
grate.
meets design
standards.