HomeMy WebLinkAboutTIR_4135Table of Contents
· Project Overview
· Core Requirement #1: Discharge at the Natural Location
· Core Requirement #2: Offsite Analysis
· Core Requirement #4: Conveyance System
· Core Requirement #5: Erosion and Sediment Control
· Core Requirement #6: Maintenance and Operations
· Core Requirement #7: Financial Guarantees and Liabilities
· Special Requirement #4: Source Control
· Special Requirement #6: Aquifer Protection Area
· Section C.1.3.1 Small Lot BMP Requirements
· Geotechnical Evaluation by Cobalt Geosciences
Project Overview:
The subject property is an existing parcel consisting of 8,520 square feet which was created by the
Plat of Puget Colony Homes in May 1968. The subject property has an existing residence, large
deck, and several out buildings. The property is very flat with a slight grade (2%) from the west
towards the east. The natural discharge location on the property is the southeast corner into a
public catch basin. There are frontage improvements required for this project along SE 2nd Street.
These improvements consist of: 5’ sidewalk, 8’ landscape strip, driveway approach, vertical curb and
gutter, and asphalt paving.
The total project <building permit and frontage improvements> consist of: 9,800 square feet of
land disturbance, 4,294 square feet of new impervious hard surfaces (of which 1,126 square feet
will be PGHS – Pollution generating Hard Surfaces), and 5,966 square feet of landscaped (pervious)
areas. Per the 2017 City of Renton Surface Water Design Manual Flow Chart Figure 1.1.2.A, The
project is defined as “Targeted Drainage Review” Category #2 per Section 1.1.2.2. The project will
be required to meet Core Requirements #1, #2, #4 through #7 and Special Requirements #4 and
#6.
The property has been visited several times between November 2019 and August 2020, there were
no indications of erosion, runoff, or souring occurring on the down gradient side of the property. It
appears, and was confirmed by the Geologist, that the soils are excellent for infiltration.
All Public utilities are available within SE 2nd Street.
Core Requirement #1: Discharge at Natural Location
The subject property and frontage improvements discharge at the southeast corner of the property
into a short section of open ditch before entering a public catch basin. This is the natural location of
discharge form the property and will be maintained and used for the developed conditions.
Core Requirement #2: Off Site Analysis:
The downstream conveyance system is tight lined 18” pipe from the south west corner of the
property to Hoquiam Avenue SE, where it enters a locked conveyance system of pipes and solid
locking lid catch basins. The downstream system was walked 700 feet downstream of the property
where the drainage enters Maplewood Creek on the south side of SE 2nd Place. Most of the
downstream system is within solid locking lid catch basins and therefore could not be accessed. The
outfall into Maplewood Creek appears to be in good condition with rock rip rap splash pad and no
indication of scouring or overtopping. Maplewood Creek was not accessible below SE 2nd Place.
King
4920 SE 2nd Downstream
Date: 8/13/2020 Notes:
The information included on this map has been compiled by King County staff from a variety of sources and is subject to changewithout notice. King County makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness,or rights to the use of such information. This document is not intended for use as a survey product. King County shall not be liablefor any general, special, indirect, incidental, or consequential damages including, but not limited to, lost revenues or lost profitsresulting from the use or misuse of the information contained on this map. Any sale of this map or information on this map isprohibited except by written permission of King County.±
#1 #2 #3
#4
#5
Maplewood Creek
Photo #1 – Natural discharge at southeast property corner ((viewing east on SE 2nd Street))
Photo #1 – Natural discharge at southeast property corner ((viewing east on SE 2nd Street))
Photo #2 – Sta. 1+26’ downstream – Exisitng public catch basin on north side of SE 2nd Street
Catch basin was clean with no indications of opvertopping or capcaity issues.
Photo #3 – Sta, 3+30’ downstream - Storm catch basin with solid locking lid in Hoquiam
Avenue SE at north side of intersection with SE 2nd Street. Could not access.
Photo #4 – Sta. 6+35’ downstream – Storm catch basin with solid locking lid in intersection of
Hoquiam Avenue SE and SE 2nd Place. Could not access
Photo #5 – Sta. 7+00’ downstream – Conveyance pipe from “solid locking lid” catch basins
discharges into Maplewood Creek on south side of SE 2nd Place. Will vegetated, rock outfall
splash pad, no indications of overtopping or erosion. System appears to have capacity. Could
not access below this point.
Core Requirement #4: Conveyance System:
The new conveyance system along the frontage will be sized for the 25-year storm event and
evaluated for backflow elevation at least 6” of storage above the 25-year event.
STORMWATER CONVEYANCE BACKWATER CALCULATION SHEET(1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)BarrelEntranceEntrance Pipe25 yearPipeOutlet InletBarrelBarrelVelocityTWFrictionHGLHeadSegmentQLengthPipe"n"ElevElevAreaVelocityHeadElevLossElevLoss(cfs)(ft)SizeValue(feet)(feet)(sq. feet)(fps)(feet)(feet)(feet)(feet)(feet)CB#1-EX.1.579012"0.012386.30384.500.791.990.061385.500.252385.750.012(*)CB#2-EX.0.331012"0.012385.50384.500.790.420.003385.500.028385.530.001(*)(*) Tail water assumed as 12" within existing 18" storm (14) (15) (16) (17) (18) (19) (20)(21)Exit Outlet Inlet Approach Bend JunctionHead Control Control Velocity Head Head HWAddRIM ELEVLoss Elev Elev Head Loss Loss Elev6"UPSTREAM (feet) (feet) (feet) (feet) (feet) (feet) (feet)overtopCBCB#1-EX. 0.061 385.83 385.10 0.061 0.061 0.028 385.98386.48388.00OK!CB#2-EX. 0.003 385.53 385.10 0.003 0.003 0.001 385.54386.04387.82OK!
Core Requirement #5: Erosion and Sediment Control:
An erosion and sedimentation control plan has been provided as part of the building permit
approval. Plan is attached.
Core Requirement #6: Maintenance and Operations:
The on-site drainage facilities will be maintained by the private property owner in accordance with
the Declaration of Covenant recorded on the property. The frontage improvements along SE 2nd
Street will be owned and maintained by the City of Renton.
Page 4 of 7
Core Requirement #7: Financial Guarantees and Liabilities:
CED Permit #:UnitReference #PriceUnitQuantity CostBackfill & compaction-embankmentESC-16.50$ CY75487.50Check dams, 4" minus rockESC-2SWDM 5.4.6.380.00$ Each Catch Basin ProtectionESC-335.50$ EachCrushed surfacing 1 1/4" minusESC-4WSDOT 9-03.9(3)95.00$ CY DitchingESC-59.00$ CY Excavation-bulkESC-62.00$ CY Fence, siltESC-7SWDM 5.4.3.11.50$ LFFence, Temporary (NGPE)ESC-81.50$ LF Geotextile FabricESC-92.50$ SY Hay Bale Silt TrapESC-100.50$ Each HydroseedingESC-11SWDM 5.4.2.40.80$ SYInterceptor Swale / DikeESC-121.00$ LF Jute MeshESC-13SWDM 5.4.2.23.50$ SY Level SpreaderESC-141.75$ LF Mulch, by hand, straw, 3" deepESC-15SWDM 5.4.2.12.50$ SY220550.00Mulch, by machine, straw, 2" deepESC-16SWDM 5.4.2.12.00$ SY Piping, temporary, CPP, 6"ESC-1712.00$ LF Piping, temporary, CPP, 8"ESC-1814.00$ LF Piping, temporary, CPP, 12"ESC-1918.00$ LF Plastic covering, 6mm thick, sandbaggedESC-20SWDM 5.4.2.34.00$ SY Rip Rap, machine placed; slopesESC-21WSDOT 9-13.1(2)45.00$ CY Rock Construction Entrance, 50'x15'x1'ESC-22SWDM 5.4.4.11,800.00$ Each Rock Construction Entrance, 100'x15'x1'ESC-23SWDM 5.4.4.13,200.00$ Each Sediment pond riser assemblyESC-24SWDM 5.4.5.22,200.00$ Each Sediment trap, 5' high berm ESC-25SWDM 5.4.5.119.00$ LF Sed. trap, 5' high, riprapped spillway berm section ESC-26SWDM 5.4.5.170.00$ LF Seeding, by handESC-27SWDM 5.4.2.41.00$ SY Sodding, 1" deep, level groundESC-28SWDM 5.4.2.58.00$ SY Sodding, 1" deep, sloped groundESC-29SWDM 5.4.2.510.00$ SY TESC SupervisorESC-30110.00$ HR2220.00Water truck, dust controlESC-31SWDM 5.4.7140.00$ HR UnitReference #PriceUnitQuantity Cost-$ Lin. Feet125.00$ each2250.00 EROSION/SEDIMENT SUBTOTAL:1,507.50SALES TAX @ 10%150.75EROSION/SEDIMENT TOTAL:1,658.25(A)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR EROSION & SEDIMENT CONTROLDescriptionNo.(A)Tree Protection Fencing Catch Basin protectionWRITE-IN-ITEMS Page 1 of 1Ref 8-H Bond Quantity WorksheetSECTION II.a EROSION_CONTROLUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 6/22/2020
CED Permit #:ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostGENERAL ITEMS Backfill & Compaction- embankmentGI-16.00$ CYBackfill & Compaction- trenchGI-29.00$ CYClear/Remove Brush, by hand (SY)GI-31.00$ SYBollards - fixedGI-4240.74$ EachBollards - removableGI-5452.34$ EachClearing/Grubbing/Tree RemovalGI-610,000.00$ AcreExcavation - bulkGI-72.00$ CYExcavation - TrenchGI-85.00$ CYFencing, cedar, 6' highGI-920.00$ LFFencing, chain link, 4'GI-1038.31$ LFFencing, chain link, vinyl coated, 6' highGI-1120.00$ LFFencing, chain link, gate, vinyl coated, 20' GI-121,400.00$ EachFill & compact - common barrowGI-1325.00$ CYFill & compact - gravel baseGI-1427.00$ CYFill & compact - screened topsoilGI-1539.00$ CYGabion, 12" deep, stone filled mesh GI-1665.00$ SYGabion, 18" deep, stone filled mesh GI-1790.00$ SYGabion, 36" deep, stone filled meshGI-18150.00$ SYGrading, fine, by handGI-192.50$ SY128320.00Grading, fine, with graderGI-202.00$ SYMonuments, 3' LongGI-21250.00$ EachSensitive Areas SignGI-227.00$ EachSodding, 1" deep, sloped groundGI-238.00$ SYSurveying, line & gradeGI-24850.00$ Day1850.00Surveying, lot location/linesGI-251,800.00$ AcreTopsoil Type A (imported)GI-2628.50$ CYTraffic control crew ( 2 flaggers )GI-27120.00$ HRTrail, 4" chipped woodGI-288.00$ SYTrail, 4" crushed cinderGI-299.00$ SYTrail, 4" top courseGI-3012.00$ SYConduit, 2"GI-315.00$ LFWall, retaining, concreteGI-3255.00$ SFWall, rockeryGI-3315.00$ SFSUBTOTAL THIS PAGE:1,170.00(B)(C)(D)(E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR STREET AND SITE IMPROVEMENTSQuantity Remaining (Bond Reduction) (B)(C)Page 1 of 3Ref 8-H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 10/5/2020
CED Permit #:ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR STREET AND SITE IMPROVEMENTSQuantity Remaining (Bond Reduction) (B)(C)ROAD IMPROVEMENT/PAVEMENT/SURFACINGAC Grinding, 4' wide machine < 1000syRI-130.00$ SY952,850.00AC Grinding, 4' wide machine 1000-2000syRI-216.00$ SYAC Grinding, 4' wide machine > 2000syRI-310.00$ SYAC Removal/DisposalRI-435.00$ SY321,120.00Barricade, Type III ( Permanent )RI-556.00$ LFGuard RailRI-630.00$ LFCurb & Gutter, rolledRI-717.00$ LFCurb & Gutter, verticalRI-812.50$ LF831,037.50Curb and Gutter, demolition and disposalRI-918.00$ LFCurb, extruded asphaltRI-105.50$ LFCurb, extruded concreteRI-117.00$ LFSawcut, asphalt, 3" depthRI-121.85$ LF96177.60Sawcut, concrete, per 1" depthRI-133.00$ LFSealant, asphaltRI-142.00$ LF96192.00Shoulder, gravel, 4" thickRI-1515.00$ SYSidewalk, 4" thickRI-1638.00$ SY381,444.00Sidewalk, 4" thick, demolition and disposalRI-1732.00$ SYSidewalk, 5" thickRI-1841.00$ SY15615.00Sidewalk, 5" thick, demolition and disposalRI-1940.00$ SYSign, Handicap RI-2085.00$ EachStriping, per stallRI-217.00$ EachStriping, thermoplastic, ( for crosswalk )RI-223.00$ SFStriping, 4" reflectorized lineRI-230.50$ LFAdditional 2.5" Crushed SurfacingRI-243.60$ SYHMA 1/2" Overlay 1.5" RI-2514.00$ SYHMA 1/2" Overlay 2"RI-2618.00$ SY1262,268.00HMA Road, 2", 4" rock, First 2500 SYRI-2728.00$ SY31868.00HMA Road, 2", 4" rock, Qty. over 2500SYRI-2821.00$ SYHMA Road, 4", 6" rock, First 2500 SYRI-2945.00$ SYHMA Road, 4", 6" rock, Qty. over 2500 SYRI-3037.00$ SYHMA Road, 4", 4.5" ATBRI-3138.00$ SYGravel Road, 4" rock, First 2500 SYRI-3215.00$ SYGravel Road, 4" rock, Qty. over 2500 SYRI-3310.00$ SYThickened EdgeRI-348.60$ LFSUBTOTAL THIS PAGE:10,572.10(B)(C)(D)(E)Page 2 of 3Ref 8-H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 10/5/2020
CED Permit #:ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR STREET AND SITE IMPROVEMENTSQuantity Remaining (Bond Reduction) (B)(C)PARKING LOT SURFACINGNo.2" AC, 2" top course rock & 4" borrowPL-121.00$ SY2" AC, 1.5" top course & 2.5" base coursePL-228.00$ SY4" select borrowPL-35.00$ SY1.5" top course rock & 2.5" base coursePL-414.00$ SYSUBTOTAL PARKING LOT SURFACING:(B)(C)(D)(E)LANDSCAPING & VEGETATIONNo.Street TreesLA-1250.00$ each1250.00Median LandscapingLA-2Right-of-Way LandscapingLA-352.00$ SY854,420.00Wetland LandscapingLA-4SUBTOTAL LANDSCAPING & VEGETATION:4,670.00(B)(C)(D)(E)TRAFFIC & LIGHTINGNo.SignsTR-1650.00$ eachStreet Light System ( # of Poles)TR-24,800.00$ eachTraffic SignalTR-3Traffic Signal ModificationTR-4SUBTOTAL TRAFFIC & LIGHTING:(B)(C)(D)(E)WRITE-IN-ITEMSConcrete removal-$ SY11ADA ramps550.00$ each21,100.00SUBTOTAL WRITE-IN ITEMS:1,100.00STREET AND SITE IMPROVEMENTS SUBTOTAL:17,512.10SALES TAX @ 10%1,751.21STREET AND SITE IMPROVEMENTS TOTAL:19,263.31(B)(C)(D)(E)Page 3 of 3Ref 8-H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 10/5/2020
CED Permit #:ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostDRAINAGE (CPE = Corrugated Polyethylene Pipe, N12 or Equivalent) For Culvert prices, Average of 4' cover was assumed. Assume perforated PVC is same price as solid pipe.) Access Road, R/DD-126.00$ SY* (CBs include frame and lid)BeehiveD-290.00$ EachThrough-curb Inlet FrameworkD-3400.00$ EachCB Type ID-41,500.00$ Each23,000.00CB Type ILD-51,750.00$ EachCB Type II, 48" diameterD-62,300.00$ Each for additional depth over 4' D-7480.00$ FTCB Type II, 54" diameterD-82,500.00$ Each for additional depth over 4'D-9495.00$ FTCB Type II, 60" diameterD-102,800.00$ Each for additional depth over 4'D-11600.00$ FTCB Type II, 72" diameterD-126,000.00$ Each for additional depth over 4'D-13850.00$ FTCB Type II, 96" diameterD-1414,000.00$ Each for additional depth over 4'D-15925.00$ FTTrash Rack, 12"D-16350.00$ EachTrash Rack, 15"D-17410.00$ EachTrash Rack, 18"D-18480.00$ EachTrash Rack, 21"D-19550.00$ EachCleanout, PVC, 4"D-20150.00$ EachCleanout, PVC, 6"D-21170.00$ EachCleanout, PVC, 8"D-22200.00$ EachCulvert, PVC, 4" D-2310.00$ LFCulvert, PVC, 6" D-2413.00$ LFCulvert, PVC, 8" D-2515.00$ LFCulvert, PVC, 12" D-2623.00$ LFCulvert, PVC, 15" D-2735.00$ LFCulvert, PVC, 18" D-2841.00$ LFCulvert, PVC, 24"D-2956.00$ LFCulvert, PVC, 30" D-3078.00$ LFCulvert, PVC, 36" D-31130.00$ LFCulvert, CMP, 8"D-3219.00$ LFCulvert, CMP, 12"D-3329.00$ LFSUBTOTAL THIS PAGE:3,000.00(B)(C)(D)(E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESQuantity Remaining (Bond Reduction) (B)(C)Page 1 of 5Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 8/10/2020
CED Permit #:ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESQuantity Remaining (Bond Reduction) (B)(C)DRAINAGE (Continued)Culvert, CMP, 15"D-3435.00$ LFCulvert, CMP, 18"D-3541.00$ LFCulvert, CMP, 24"D-3656.00$ LFCulvert, CMP, 30"D-3778.00$ LFCulvert, CMP, 36"D-38130.00$ LFCulvert, CMP, 48"D-39190.00$ LFCulvert, CMP, 60"D-40270.00$ LFCulvert, CMP, 72"D-41350.00$ LFCulvert, Concrete, 8"D-4242.00$ LFCulvert, Concrete, 12"D-4348.00$ LFCulvert, Concrete, 15"D-4478.00$ LFCulvert, Concrete, 18"D-4548.00$ LFCulvert, Concrete, 24"D-4678.00$ LFCulvert, Concrete, 30"D-47125.00$ LFCulvert, Concrete, 36"D-48150.00$ LFCulvert, Concrete, 42"D-49175.00$ LFCulvert, Concrete, 48"D-50205.00$ LFCulvert, CPE Triple Wall, 6" D-5114.00$ LFCulvert, CPE Triple Wall, 8" D-5216.00$ LFCulvert, CPE Triple Wall, 12" D-5324.00$ LFCulvert, CPE Triple Wall, 15" D-5435.00$ LFCulvert, CPE Triple Wall, 18" D-5541.00$ LFCulvert, CPE Triple Wall, 24" D-5656.00$ LFCulvert, CPE Triple Wall, 30" D-5778.00$ LFCulvert, CPE Triple Wall, 36" D-58130.00$ LFCulvert, LCPE, 6"D-5960.00$ LFCulvert, LCPE, 8"D-6072.00$ LFCulvert, LCPE, 12"D-6184.00$ LFCulvert, LCPE, 15"D-6296.00$ LFCulvert, LCPE, 18"D-63108.00$ LFCulvert, LCPE, 24"D-64120.00$ LFCulvert, LCPE, 30"D-65132.00$ LFCulvert, LCPE, 36"D-66144.00$ LFCulvert, LCPE, 48"D-67156.00$ LFCulvert, LCPE, 54"D-68168.00$ LFSUBTOTAL THIS PAGE:(B)(C)(D)(E)Page 2 of 5Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 8/10/2020
CED Permit #:ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESQuantity Remaining (Bond Reduction) (B)(C)DRAINAGE (Continued)Culvert, LCPE, 60"D-69180.00$ LFCulvert, LCPE, 72"D-70192.00$ LFCulvert, HDPE, 6"D-7142.00$ LFCulvert, HDPE, 8"D-7242.00$ LFCulvert, HDPE, 12"D-7374.00$ LFCulvert, HDPE, 15"D-74106.00$ LFCulvert, HDPE, 18"D-75138.00$ LFCulvert, HDPE, 24"D-76221.00$ LFCulvert, HDPE, 30"D-77276.00$ LFCulvert, HDPE, 36"D-78331.00$ LFCulvert, HDPE, 48"D-79386.00$ LFCulvert, HDPE, 54"D-80441.00$ LFCulvert, HDPE, 60"D-81496.00$ LFCulvert, HDPE, 72"D-82551.00$ LFPipe, Polypropylene, 6"D-8384.00$ LFPipe, Polypropylene, 8"D-8489.00$ LFPipe, Polypropylene, 12"D-8595.00$ LFPipe, Polypropylene, 15"D-86100.00$ LFPipe, Polypropylene, 18"D-87106.00$ LFPipe, Polypropylene, 24"D-88111.00$ LFPipe, Polypropylene, 30"D-89119.00$ LFPipe, Polypropylene, 36"D-90154.00$ LFPipe, Polypropylene, 48"D-91226.00$ LFPipe, Polypropylene, 54"D-92332.00$ LFPipe, Polypropylene, 60"D-93439.00$ LFPipe, Polypropylene, 72"D-94545.00$ LFCulvert, DI, 6"D-9561.00$ LFCulvert, DI, 8"D-9684.00$ LFCulvert, DI, 12"D-97106.00$ LFCulvert, DI, 15"D-98129.00$ LFCulvert, DI, 18"D-99152.00$ LFCulvert, DI, 24"D-100175.00$ LFCulvert, DI, 30"D-101198.00$ LFCulvert, DI, 36"D-102220.00$ LFCulvert, DI, 48"D-103243.00$ LFCulvert, DI, 54"D-104266.00$ LFCulvert, DI, 60"D-105289.00$ LFCulvert, DI, 72"D-106311.00$ LFSUBTOTAL THIS PAGE:(B)(C)(D)(E)Page 3 of 5Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 8/10/2020
CED Permit #:ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESQuantity Remaining (Bond Reduction) (B)(C)Specialty Drainage ItemsDitching SD-19.50$ CYFlow Dispersal Trench (1,436 base+)SD-328.00$ LF French Drain (3' depth)SD-426.00$ LFGeotextile, laid in trench, polypropyleneSD-53.00$ SYMid-tank Access Riser, 48" dia, 6' deepSD-62,000.00$ EachPond Overflow SpillwaySD-716.00$ SYRestrictor/Oil Separator, 12"SD-81,150.00$ EachRestrictor/Oil Separator, 15"SD-91,350.00$ EachRestrictor/Oil Separator, 18"SD-101,700.00$ EachRiprap, placedSD-1142.00$ CYTank End Reducer (36" diameter)SD-121,200.00$ EachInfiltration pond testingSD-13125.00$ HRPermeable PavementSD-14Permeable Concrete SidewalkSD-15Culvert, Box __ ft x __ ftSD-16SUBTOTAL SPECIALTY DRAINAGE ITEMS:(B)(C)(D)(E)STORMWATER FACILITIES (Include Flow Control and Water Quality Facility Summary Sheet and Sketch)Detention PondSF-1Each Detention TankSF-2Each Detention VaultSF-3Each Infiltration PondSF-4Each Infiltration TankSF-5Each Infiltration VaultSF-6Each Infiltration TrenchesSF-7Each Basic Biofiltration SwaleSF-8Each Wet Biofiltration SwaleSF-9Each WetpondSF-10Each WetvaultSF-11Each Sand FilterSF-12Each Sand Filter VaultSF-13Each Linear Sand FilterSF-14Each Proprietary FacilitySF-15Each Bioretention FacilitySF-16Each SUBTOTAL STORMWATER FACILITIES:(B)(C)(D)(E)Page 4 of 5Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 8/10/2020
CED Permit #:ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESQuantity Remaining (Bond Reduction) (B)(C)WRITE-IN-ITEMS (INCLUDE ON-SITE BMPs)12" d.i. storm pipeWI-1100.00$ L.F.10610,600.00WI-2WI-3WI-4WI-5WI-6WI-7WI-8WI-9WI-10WI-11WI-12WI-13WI-14WI-15SUBTOTAL WRITE-IN ITEMS:10,600.00DRAINAGE AND STORMWATER FACILITIES SUBTOTAL:13,600.00SALES TAX @ 10%1,360.00DRAINAGE AND STORMWATER FACILITIES TOTAL:14,960.00(B)(C)(D)(E)Page 5 of 5Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 8/10/2020
CED Permit #:ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostConnection to Existing WatermainW-12,000.00$ EachDuctile Iron Watermain, CL 52, 4 Inch DiameterW-250.00$ LFDuctile Iron Watermain, CL 52, 6 Inch DiameterW-356.00$ LFDuctile Iron Watermain, CL 52, 8 Inch DiameterW-460.00$ LFDuctile Iron Watermain, CL 52, 10 Inch DiameterW-570.00$ LFDuctile Iron Watermain, CL 52, 12 Inch DiameterW-680.00$ LFGate Valve, 4 inch DiameterW-7500.00$ EachGate Valve, 6 inch DiameterW-8700.00$ EachGate Valve, 8 Inch DiameterW-9800.00$ EachGate Valve, 10 Inch DiameterW-101,000.00$ EachGate Valve, 12 Inch DiameterW-111,200.00$ EachFire Hydrant AssemblyW-124,000.00$ EachPermanent Blow-Off AssemblyW-131,800.00$ EachAir-Vac Assembly, 2-Inch DiameterW-142,000.00$ EachAir-Vac Assembly, 1-Inch DiameterW-151,500.00$ EachCompound Meter Assembly 3-inch DiameterW-168,000.00$ EachCompound Meter Assembly 4-inch DiameterW-179,000.00$ EachCompound Meter Assembly 6-inch DiameterW-1810,000.00$ EachPressure Reducing Valve Station 8-inch to 10-inchW-1920,000.00$ EachWATER SUBTOTAL:SALES TAX @ 10%WATER TOTAL:(B)(C)(D)(E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR WATERQuantity Remaining (Bond Reduction) (B)(C)Page 1 of 1Ref 8-H Bond Quantity WorksheetSECTION II.d WATERUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 6/22/2020
CED Permit #:ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostClean OutsSS-11,000.00$ EachGrease Interceptor, 500 gallonSS-28,000.00$ EachGrease Interceptor, 1000 gallonSS-310,000.00$ EachGrease Interceptor, 1500 gallonSS-415,000.00$ EachSide Sewer Pipe, PVC. 4 Inch DiameterSS-580.00$ LFSide Sewer Pipe, PVC. 6 Inch DiameterSS-695.00$ LFSewer Pipe, PVC, 8 inch DiameterSS-7105.00$ LFSewer Pipe, PVC, 12 Inch DiameterSS-8120.00$ LFSewer Pipe, DI, 8 inch DiameterSS-9115.00$ LFSewer Pipe, DI, 12 Inch DiameterSS-10130.00$ LFManhole, 48 Inch DiameterSS-116,000.00$ EachManhole, 54 Inch DiameterSS-136,500.00$ EachManhole, 60 Inch DiameterSS-157,500.00$ EachManhole, 72 Inch DiameterSS-178,500.00$ EachManhole, 96 Inch DiameterSS-1914,000.00$ EachPipe, C-900, 12 Inch DiameterSS-21180.00$ LFOutside DropSS-241,500.00$ LSInside DropSS-251,000.00$ LSSewer Pipe, PVC, ____ Inch DiameterSS-26Lift Station (Entire System)SS-27LSSANITARY SEWER SUBTOTAL:SALES TAX @ 10%SANITARY SEWER TOTAL:(B)(C)(D)(E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR SANITARY SEWERQuantity Remaining (Bond Reduction) (B)(C)Page 1 of 1Ref 8-H Bond Quantity WorksheetSECTION II.e SANITARY SEWERUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 6/22/2020
Planning Division |1055 South Grady Way – 6th Floor | Renton, WA 98057 (425) 430-7200Date:Name:Project Name: PE Registration No:CED Plan # (LUA):Firm Name:CED Permit # (U):Firm Address:Site Address:Phone No.Parcel #(s):Email Address:Project Phase: Site Restoration/Erosion Sediment Control Subtotal (a)Existing Right-of-Way Improvements Subtotal (b)(b)19,263.31$ Future Public Improvements Subtotal(c)-$ Stormwater & Drainage Facilities (Public & Private) Subtotal(d)(d)14,960.00$ (e)(f)Site RestorationCivil Construction PermitMaintenance Bond6,844.66$ Bond Reduction2Construction Permit Bond Amount 3Minimum Bond Amount is $10,000.001 Estimate Only - May involve multiple and variable components, which will be established on an individual basis by Development Engineering.2 The City of Renton allows one request only for bond reduction prior to the maintenance period. Reduction of not more than 70% of the original bond amount, provided that the remaining 30% willcover all remaining items to be constructed. 3 Required Bond Amounts are subject to review and modification by Development Engineering.* Note: The word BOND as used in this document means any financial guarantee acceptable to the City of Renton.** Note: All prices include labor, equipment, materials, overhead and profit. EST1((b) + (c) + (d)) x 20%-$ MAINTENANCE BOND */**(after final acceptance of construction)1,658.25$ 19,263.31$ 43,854.97$ 1,658.25$ -$ 14,960.00$ -$ 45,513.22$ P (a) x 100%SITE IMPROVEMENT BOND QUANTITY WORKSHEET BOND CALCULATIONS10/5/2020Darrell L. Offe, Jr.#27460Offe Engineers, PLLCR((b x 150%) + (d x 100%))S(e) x 150% + (f) x 100%Bond Reduction: Existing Right-of-Way Improvements (Quantity Remaining)2Bond Reduction: Stormwater & Drainage Facilities (Quantity Remaining)2T(P +R - S)Prepared by:Project InformationCONSTRUCTION BOND AMOUNT */**(prior to permit issuance)425-260-3412darrell.offe@comcast.net4920 SE 2nd Frontage Improvements 4920 SE 2nd Street692800-0450FOR APPROVAL 13932 SE 159th PlacePage 1 of 1Ref 8-H Bond Quantity WorksheetSECTION III. BOND WORKSHEETUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 10/5/2020
Special Requirement #4: Source Control:
This project does not require a commercial building or commercial site development permit;
therefore, Source Controls are not required.
Special Requirement #6: Aquifer Protection Area:
This project is not located within an Aquifer Protection Zone 1 or 2 per map attached; therefore,
Special Requirement #6 is not required.
Projectx
Section C.1.3.1 Small Lot BMP Requirements
Site Characteristics:
Lot Area: 8,520 square feet
Developed Conditions:
Roof area: 2,526 square feet
Uncovered Driveway: 534 square feet (PGHS)
Uncovered Patio/walkway/landing: 68 square feet
Offsite (Frontage Improvements)
Sidewalk w/ADA ramps area: 574 sq. feet
Landscape area: 574 sq. feet
Curb, gutter, and paving area: 385 sq. feet
Driveway approach area: 207 sq. feet
Total Proposed Hard Surfaces: 4,294 square feet
Total Proposed Pervious Surfaces: 5,966 square feet
Flow Control BMP Description:
Lot Area = 8,520 square feet; therefore, small lot.
Evaluate Small Lot BMP Requirements per 2017 CRSWDM, Section C.1.3.1
1. Feasibility of Full Dispersion – There is inadequate space on the downgradient side of the lot
to provide 100 feet of dispersion flow path – not feasible
2. Feasibility of Full Infiltration of Roof Area – Per the attached Geologist Report by Cobalt
Geosciences, the underlying soils are medium sands and gravels, useable for infiltration.
Feasible
Design sizing: Use Section C.2.2.3; Gravel Filled Trenches – 30 linear feet of trench per
1,000 square feet of roof area.
2,526/1,000 * 30 =75.78 feet USE 76 feet
3. (i) Feasibility of Full Infiltration of other hard surfaces – the on-site soils are adequate to
provide full infiltration per Cobalt Geosciences. Feasible
Design sizing: Use Section C.2.2.3; Gravel Filled Trenches – 30 linear feet of trench per
1,000 square feet of roof area.
(534+68)/1,000 *30 = 18.06 feet USE 18 feet
Off Site frontage Improvements: Impervious of 1,166 square feet and pervious area of574
square feet, there is no available BMP mitigation for this strip of improvements except to
connect to the public storm within SE 2nd Street.
SOIL EVALUATION by COBALT GEOSCIENCES
Cobalt Geosciences, LLC
P.O. Box 82243
Kenmore, Washington 98028
www.cobaltgeo.com (206) 331-1097
May 18, 2020
Mr. Bob Wenzl
Tuscany Homes
RE: Stormwater Feasibility Evaluation
Proposed Residence
4920 SE 2nd Street
Parcel No. 6928000450
Renton, Washington
Dear Mr. Wenzl,
In accordance with your authorization, Cobalt Geosciences, LLC has prepared this letter to
discuss the results of our stormwater feasibility evaluation at the referenced site.
The purpose of our evaluation was to determine the feasibility of utilizing infiltration devices for
stormwater runoff management.
Site and Project Description
The site is located at 4920 SE 2nd Street in Renton, Washington. The site consists of one parcel
with a total area of about 8,580 square feet.
The property is vegetated with grasses, bushes/shrubs, blackberry vines, ivy, and variable
diameter evergreen and deciduous trees.
The site is nearly level to slightly sloping from north to south at magnitudes of less than 5 percent
and relief of about 4 feet.
The property is bordered to the east, west, and north by residential parcels and to the south by SE
2nd Street.
The project includes construction of a new residence on the parcel. Stormwater management may
include dispersion, detention, or infiltration facilities depending on feasibility.
Area Geology
The Geologic Map of King County indicates that the site is underlain by Vashon Glacial Till.
Vashon Glacial Till is typically characterized by an unsorted, non-stratified mixture of clay, silt,
sand, gravel, cobbles and boulders in variable quantities. These materials are typically dense and
relatively impermeable. The poor sorting reflects the mixing of the materials as these sediments
were overridden and incorporated by the glacial ice.
Soil & Groundwater Conditions
As part of our evaluation, we excavated one test pit to determine the shallow soil and groundwater
conditions, where accessible.
The test pit encountered approximately 6 inches of topsoil and vegetation underlain by
approximately 3.5 feet of loose to medium dense, silty-fine to medium grained sand with gravel
May 18, 2020 Page 2 of 3 Stormwater Feasibility Evaluation
www.cobaltgeo.com (206) 331-1097
(Weathered Recessional Outwash?). These materials were underlain by 4 feet of medium dense,
fine to medium grained sand with gravel (Recessional Outwash). Glacial till was encountered
below the sand deposits.
Groundwater was encountered in in TP-1 at 8 feet below grade. Groundwater appears to be
perched between the recessional outwash and underlying glacial till.
Stormwater Management Feasibility
The site is underlain by normally consolidated recessional outwash and at depth by dense glacial
till. Groundwater was observed at 8 feet below grade in the test pit.
Because the recessional deposits have not been overridden by glacial ice, this soil unit is
considered normally-consolidated. The Washington State Department of Ecology 2015
Stormwater Management Manual for Western Washington allows determination of infiltration
rates of this soil unit by Soil Particle Size Distribution testing. This method involves using a
logarithmic equation and grain size values along with correction factors for testing type, soil
homogeneity, and influent control.
The equation in conjunction with sieve analysis results yields a design infiltration rate of 1.4
inches per hour in the coarse sand deposits below the upper weathered soils (generally 3 to 4 feet
below grade). These rates reflect application of correction factors for variability (0.33 used),
influent control (0.9), and testing analysis type (0.4). The King County Surface Water Design
Manual soil designation of Sand may be used in facility sizing.
We recommend using infiltration trenches that extend at least 6 inches into the sand deposits
while maintaining at least 12 inches of clearance above groundwater.
Any dense materials or interbeds of fine grained soils should be removed and replaced with
coarse clean rock, if encountered during system placement.
We should be provided with final plans for review to determine if the intent of our
recommendations has been incorporated or if additional modifications are needed. Verification
testing of infiltration systems should be performed during construction.
Erosion and Sediment Control
Erosion and sediment control (ESC) is used to reduce the transportation of eroded sediment to
wetlands, streams, lakes, drainage systems, and adjacent properties. Erosion and sediment
control measures should be implemented, and these measures should be in general accordance
with local regulations. At a minimum, the following basic recommendations should be
incorporated into the design of the erosion and sediment control features for the site:
Schedule the soil, foundation, utility, and other work requiring excavation or the disturbance
of the site soils, to take place during the dry season (generally May through September).
However, provided precautions are taken using Best Management Practices (BMP’s), grading
activities can be completed during the wet season (generally October through April).
All site work should be completed and stabilized as quickly as possible.
Additional perimeter erosion and sediment control features may be required to reduce the
possibility of sediment entering the surface water. This may include additional silt fences, silt
May 18, 2020 Page 3 of 3 Stormwater Feasibility Evaluation
www.cobaltgeo.com (206) 331-1097
fences with a higher Apparent Opening Size (AOS), construction of a berm, or other filtration
systems.
Any runoff generated by dewatering discharge should be treated through construction of a
sediment trap if there is sufficient space. If space is limited other filtration methods will need
to be incorporated.
Closure
The information presented herein is based upon professional interpretation utilizing standard
practices and a degree of conservatism deemed proper for this project. We emphasize that this
report is valid for this project as outlined above and for the current site conditions, and should not
be used for any other site
Sincerely,
Cobalt Geosciences, LLC
Exp 6/26/2020
Phil Haberman, PE, LG, LEG
Principal
PH/sc
Proposed Residence
4920 SE 2nd Street
Renton, Washington
N
SITE PLAN
FIGURE 1
Cobalt Geosciences, LLCP.O. Box 82243 Kenmore, WA 98028
(206) 331-1097
www.cobaltgeo.com
cobaltgeo@gmail.com
PT
Well-graded gravels, gravels, gravel-sand mixtures, little or no fines
Poorly graded gravels, gravel-sand mixtures, little or no fines
Silty gravels, gravel-sand-silt mixtures
Clayey gravels, gravel-sand-clay mixtures
Well-graded sands, gravelly sands, little or no fines
COARSE
GRAINED
SOILS
(more than 50%
retained on
No. 200 sieve)
Primarily organic matter, dark in color,
and organic odor Peat, humus, swamp soils with high organic content (ASTM D4427)HIGHLY ORGANIC
SOILS
FINE GRAINED
SOILS
(50% or more
passes the
No. 200 sieve)
MAJOR DIVISIONS SYMBOL TYPICAL DESCRIPTION
Gravels
(more than 50%
of coarse fraction
retained on No. 4
sieve)
Sands
(50% or more
of coarse fraction
passes the No. 4 sieve)
Silts and Clays(liquid limit lessthan 50)
Silts and Clays
(liquid limit 50 or
more)
Organic
Inorganic
Organic
Inorganic
Sands with
Fines (more than 12% fines)
Clean Sands(less than 5%fines)
Gravels with
Fines
(more than 12%
fines)
Clean Gravels
(less than 5%
fines)
Unified Soil Classification System (USCS)
Poorly graded sand, gravelly sands, little or no fines
Silty sands, sand-silt mixtures
Clayey sands, sand-clay mixtures
Inorganic silts of low to medium plasticity, sandy silts, gravelly silts,
or clayey silts with slight plasticity
Inorganic clays of low to medium plasticity, gravelly clays, sandy clays,
silty clays, lean clays
Organic silts and organic silty clays of low plasticity
Inorganic silts, micaceous or diatomaceous fine sands or silty soils,
elastic silt
Inorganic clays of medium to high plasticity, sandy fat clay,
or gravelly fat clay
Organic clays of medium to high plasticity, organic silts
Moisture Content Definitions
Grain Size Definitions
Dry Absence of moisture, dusty, dry to the touch
Moist Damp but no visible water
Wet Visible free water, from below water table
Grain Size Definitions
Description Sieve Number and/or Size
Fines <#200 (0.08 mm)
Sand
-Fine
-Medium
-Coarse
Gravel
-Fine
-Coarse
Cobbles
Boulders
#200 to #40 (0.08 to 0.4 mm)
#40 to #10 (0.4 to 2 mm)
#10 to #4 (2 to 5 mm)
#4 to 3/4 inch (5 to 19 mm)
3/4 to 3 inches (19 to 76 mm)
3 to 12 inches (75 to 305 mm)
>12 inches (305 mm)
Classification of Soil Constituents
MAJOR constituents compose more than 50 percent,
by weight, of the soil. Major constituents are capitalized
(i.e., SAND).
Minor constituents compose 12 to 50 percent of the soil
and precede the major constituents (i.e., silty SAND).
Minor constituents preceded by “slightly” compose
5 to 12 percent of the soil (i.e., slightly silty SAND).
Trace constituents compose 0 to 5 percent of the soil(i.e., slightly silty SAND, trace gravel).
Relative Density Consistency
(Coarse Grained Soils) (Fine Grained Soils)
N, SPT, Relative
Blows/FT Density
0 - 4 Very loose
4 - 10 Loose
10 - 30 Medium dense
30 - 50 Dense
Over 50 Very dense
N, SPT, Relative
Blows/FT Consistency
Under 2 Very soft
2 - 4 Soft4 - 8 Medium stiff8 - 15 Stiff15 - 30 Very stiff
Over 30 Hard
Cobalt Geosciences, LLCP.O. Box 82243 Kenmore, WA 98028(206) 331-1097
www.cobaltgeo.com
cobaltgeo@gmail.com
Soil Classification Chart Figure C1
Proposed Development
4920 SE 2nd Street
Renton, Washington
Test Pit
Log
Cobalt Geosciences, LLCP.O. Box 82243 Kenmore, WA 98028
(206) 331-1097
www.cobaltgeo.com
cobaltgeo@gmail.com
Test Pit TP-1
Date: April 30, 2020
Contractor: Wenzl
Depth: 9’
Elevation: Logged By: PH Checked By: SC
Groundwater: 8’
Material Description
Moisture Content (%)PlasticLimit Liquid
Limit
10 20 30 400 50
1
2
3
4
5
6
DCP Equivalent N-Value
7
8
9
10
SM
Dense to very dense, silty-fine to medium grained sand with gravel,
grayish brown, moist. (Glacial Till)SM
End of Test Pit 9’
Topsoil/Grass
Loose to medium dense, silty-fine to medium grained sand with gravel,
yellowish brown, moist. (Weathered Recessional Outwash)
Medium dense to dense, fine to medium grained sand with gravel,
grayish brown, moist to wet. (Recessional Outwash?)
SP