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Home My WebLink AboutStudies APPLICANT 8/30/2021380 Q Street, Ste 200 Springfield, Oregon 97477 (541) 302-9790 dylan mciver@ao-engr. com A Et O Engineering LLC Drainage Memorandum Ta Dean Pickett, Ridgeview Gardens Apartments Prepared By: Dylan McIver, EIT Reviewed By. Scott Morris, PE SCOtt. ally signed by Soon Scott Morris, PE Date: 8/13/2021 Morris PE net,: 2021.08,13 Tarmrap & T.L.: 17-023332 T.L. 3800 r 09:10:59-07'00' Re: Storm Drainage Design for Ridgeview Gardens Apartments, Springfield, Oregon Project Overview This storm analysis is for a proposed apartment complex located at 5000 Main Street in Springfield, Oregon. The proposed 1.8 -acre development includes 3 multi -family residential apartment buildings, an office, and parking lots. The existing shared driveway south of the site is proposed to keep its natural drainage pattern which flows to an existing system for NW Community Credit Union. The roof drainage from the apartments is proposed be routed to storm planters located on the west and northeast sides of the property. Roof drainage from the office building is proposed to be routed to the dual chamber catch basin in the proposed parking lot just to the east of the building. The main outlet of each storm management facility is infiltration with overflow for the 2 -year storm event being directed to the existing 42" storm line in Main Street. The storm management facilities will provide some level of detention as well as filtration for the water quality storm event before slormwater enters the public drainage system. The existing 42" storm line in Main street is around 9 feet down allowing adequate depth for connection of overflows from the site. Site Solis The site is within the 99 -year time of travel wellhead zone and requires that the rain gardens have at least 12" of growing media for stormwater entering the ground. PBS Engineering performed two infiltration tests (open -hole, falling -head) at the site on September 9'h, 2020. The infiltration rate for the test pit at the north end (TP -2) was used for Storm Planter #1 and #2. The infiltration rate at the south end (TP -7) of the site was used for the rain garden. Groundwaterwas encountered at 11 feet below ground surface. The northern test pit had an infiltration rate of 4.5 in1hr and the southern test pit was 2.1 in/hr. With a factor of safety of 2.0 being applied, infiltration rates of 2.25 and 1.05 in/hr were used respectively in rain garden design. Storm Design The storm management facilities are designed to process drainage from the 3 apartment roofs, the office roof, and the main parking lot area, with the rain garden being for the surrounding parking lot only. All storm management facilities are designed as infiltration and flow control facilities. The primary outlet is infiltration with an assumed infiltration rate of 2.25 in/hr for Storm Planters #1 and #2, and 1.05 in/hr for the rain garden in the center of the parking area. All storm management facilities have a 4" standpipe that is designed to convey stormwater overflow, for larger storm events (2 -year and 25 -year) to the existing public system within Main Street. The small northern parking lot area (approx. 4500 SF) will be treated via dual chambered catch basin with fossil filter insert. All stornwaler facilities direct flow to the existing public system in Main Street via a proposed 10" pipe. The rain garden dimensions were designed with the following variables: Drainage Area Impervious Area (sq -ft) CN Parking lot 24,403 98 Apt #1 10,171 98 Apt #2 10,171 98 Apt #3 10,171 98 North Parking 4,483 98 Office Roof 2,024 98 Existing Conditions: Water quality Storm = 0.83 inches in 24 hours 2 -Year Design storm = 3.3 inches in 24 hours 2lPage Area CN HydroCAD Description (Acres) Value Node Grassland HSG C 1.80 1 69 7S Water quality Storm = 0.83 inches in 24 hours 2 -Year Design storm = 3.3 inches in 24 hours 2lPage The analysis was completed utilizing HydroCAD software, the Santa Barbara Urban Hydrograph runoff method. The calculation sheets are attached, and the analysis results outlined in the table above. Rainfall Event ExistingFlow Post Construction Top of Bottom Bottom Bottom Max Water Drawdown North Parking Lot 4.483 18.4 Open of of Soil Elevation Elevation Time Surface Storage Open Media of Rock During for Area Side (ft) Storage (ft) Chamber Design Facility (Sq -ft) slope (ft) (ft) Storm (ft) (Hours) Storm 3:1 500 498.00 497.00 510 gy6.00 499.84 25.3 Planter #1 Storm 500 498.00 497.00 Planter #2 438 3:1 496.00 498.98 26.1 Rain 498.83 496.53 495.53 1544 494 .53 497.94 29.4 Garden #1 3:1 The analysis was completed utilizing HydroCAD software, the Santa Barbara Urban Hydrograph runoff method. The calculation sheets are attached, and the analysis results outlined in the table above. Rainfall Event ExistingFlow Post Construction Peak Flow efs) 2 -Year .15 0.18 Driveway Areas can Site Slormwater from the existing shared driveway will not change its existing drainage pattern and therefore was not included in the calculations. This area currently is graded to tolled in the drainage system for Northwest Community Credit Union. The north portion of the parking lot is being treated via dual chambered catch basin with fossil fitter insert. The table below shows the percentage of non -roof impervious area being treated mechanically is less than 50% so it meets City of Springfield design standard 3.02.6. Conclusion For the storm events analyzed, the storm management facilities are adequately sized to fully infiltrate the water quality storm event. For the 2 -year storm event, the storm management facilities will overflow and be conveyed to the existing 42" public storm line in Main Street. The 3lPage Square Feet Paved Area Percentage Primary Parking Lot 24,403 81.6 North Parking Lot 4.483 18.4 Conclusion For the storm events analyzed, the storm management facilities are adequately sized to fully infiltrate the water quality storm event. For the 2 -year storm event, the storm management facilities will overflow and be conveyed to the existing 42" public storm line in Main Street. The 3lPage storm line in Main street is approximately 9 feet deep, allowing the overflow from the site to be tied into it. The post construction peak flow during the 2 -year storm event is slightly higher than the existing condition. However, the total amount over is modeled to be 0.03 GIS, which is negligible. This will not rause any safety or maintenance issues to the downstream system. The analysis shows the storm system for the development is adequately sized for the water quality storm event, with a drawdown time that meets code and will not cause problems in the downstream system. Water surface levels in all facilities are below lop of bank during analyzed storm events. Therefore, the proposed system does not create any safety concerns for property or persons. Attachments 1. Ridgeview Gardens - HydmCAD Report 2. Geotech Report 41Page n) Existing Conditions 1 SS 8S Patin, tNorth 3S smragarom\ Apartme 0 i6 Pat Lot Dua 13R 5S hamber CB \27 2 1 2 �� 2P nu Planter#1 Storm Planterk2 43 / Rein Gertl9n #1 \ Apadnmmt#2 Apertment#1 10"S m Subcat RC.Ch -OD Link Routing Diagram Por Ridgevlew Apa"ements Storm Analysis-SDM-8.7-202 J Prepared by A& O Engineering, Printed 8/1212021 HydroCAD®10.10-5a en 04993 ® 2020 HydroCAD Software Solutions LLC Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-2021 Prepared by A & O Engineering Printed 8/12/2021 HydroCAD®10.10-5a sln 04993 © 2020 HydroCAD Software Solutions LLC Paae 2 Rainfall Events Listing (selected events) Event# Event Storm Type Curve Mode Duration B/B Depth AMC Name (hours) (inches) 1 2 Year Type IA 24 -hr Default 24.00 1 3.30 2 2 WQ Type IA 24 -hr Default 24.00 1 0.83 2 Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-2 Type IA 24 -hr 2 YearRainfa/1=3.30" Prepared by A & O Engineering Printed 8/12/2021 HydroCAD@ 10.10-5a s/n 04993 @2020 HvdroCAD Software Solutions LLC Paoe 3 Summary for Subcatchment 1S: Parking Lot Runoff = 0.41 cfs @ 7.98 hrs, Volume= 0.143 af, Depth= 3.07" Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-50.00 hrs, dt= 0.05 hrs Type IA 24 -hr 2 Year Rainfall=3.30" Impervious Area To Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment 1S: Parking Lot Hydrograph 0.45 0.41 cfs 0.4 -,Type IA 24 -hr 0.35 2 Year Rainfall=3.30" 0.3 Runoff Area=24,403 sf 0.25 Runoff Volume=0.143 of Runoff Depth=3.07' 0 0.2 a Tc=10.0-min 0.15 CN=0/98 0.1 0 5 10 15 20 25 30 Time (hours) — Runoff Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-2 Type IA 24 -hr 2 Year Rainfall=3.30" Prepared by A & O Engineering Printed 8/12/2021 HydroCAD® 10.10-5a s/n 04993 ©2020 HydroCAD Software Solutions LLC Page 4 Summary for Subcatchment 3S: Apartment #3 Runoff = 0.17 cfs @ 7.98 hrs, Volume= 0.060 ef, Depth= 3.07' Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-50.00 hrs, dt= 0.05 hrs Type IA 24 -hr 2 Year Rainfall=3.30" Area (sf) CN Description 9,530 98 Unconnected roofs, HSG B 641 98 Unconnected pavement HSG B 10,171 98 Weighted Average 10,171 98 100.00% Impervious Area Tc Length 10.0 0.1 0.1 0.1 w 0.1 0. 3 LL O.0 C 0.17 Cfs Description Subcatchment 3S: Apartment #3 Hydrograph Type IA 24 -hr 2 Year Rainfall=3.30" Runoff Area=10,171 sf Runoff Volume=0.060 of Runoff Depth=3.07' Tc=10.0 min CN=0198 0 5 10 15 20 25 30 35 40 45 Time (hours) — Runoff Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-2 Type IA 24 -hr 2 Year Rainfall=3.30" Prepared by A & O Engineering Printed 8/12/2021 HydroCADO 10.10-5a s/n 04993 © 2020 HydroCAD Software Solutions LLC Page 5 Summary for Subcatchment 4S: Apartment #2 Runoff = 0.17 cfs @ 7.98 hrs, Volume= 0.060 af, Depth= 3.07' Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-50.00 hrs, dt= 0.05 hrs Type IA 24 -hr 2 Year Rainfall=3.30" Area (sf) CN Description 9,530 98 Unconnected roofs, HSG B 641 98 Unconnected pavement, HSG B 10,171 98 Weighted Average 10,171 98 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment 4S: Apartment #2 Hydrograph Type IA 24 -hr 2 Year Rainfall=3.30" Runoff Area=10,171 sf Runoff Volume=0.060 of Runoff Depth=3.07' Tc=10.0 min CN=0/98 0 5 10 15 20 25 30 35 40 45 50 Time (hours) — Runoff 0.18 0.17 cfs 0.16 0.14 0.12 m 0.1 3 LL 0.08 Type IA 24 -hr 2 Year Rainfall=3.30" Runoff Area=10,171 sf Runoff Volume=0.060 of Runoff Depth=3.07' Tc=10.0 min CN=0/98 0 5 10 15 20 25 30 35 40 45 50 Time (hours) — Runoff Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-2 Type IA 24 -hr 2 Year Rainfall=3.30" Prepared by A & O Engineering Printed 8/12/2021 HvdroCAD®10.10-5a s/n 04993 © 2020 HvdroCAD Software Solutions LLC Pace 6 Summary for Subcatchment 5S: Apartment #1 Runoff = 0.17 cfs @ 7.98 hrs, Volume= 0.060 af, Depth= 3.07' Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-50.00 hrs, dt= 0.05 hrs Type IA 24 -hr 2 Year Rainfall=3.30" Area (sf) CN Description 9,530 98 Unconnected roofs, HSG B 641 98 Unconnected pavement, HSG B 10,171 98 Weighted Average 10,171 98 100.00% Impervious Area Tc Length Slope Velocity Capacity Description ,_;_% /feed IHIH\ tHl --- I W.% 10.0 Direct Entry, Subcatchment 5S: Apartment #1 Hydrograph 0.18 0.17 Cfs 0.16 Type IA 24 -hr 0.14 2 Year Rainfall=3.30" Runoff Area=10,171 sf 0.12 Runoff Volume=0.060 of 3 0.1 Runoff Depth=3.07' 0 0.08 Tc=10.0 min n nal CN=0/98 5 10 15 20 25 30 35 40 45 50 Time (hours) —Runoff Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-2 Type IA 24 -hr 2 Year Rainfal1=3.30" Prepared by A & O Engineering Printed 8/12/2021 HydroCAD® 10.10-5a s/n 04993 @ 2020 HydroCAD Software Solutions LLC Paas 7 Summary for Subcatchment 7S: Existing Conditions Runoff = 0.15 cfs @ 8.25 hrs, Volume= 0.125 af, Depth= 0.84" Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-50.00 hrs, dt= 0.05 hrs Type IA 24 -hr 2 Year Rainfall=3.30" 69 100,00% Pervious Area Tc Length Description 25.1 234 0.0100 0.16 Sheet Flow, Grass: Short n=0.150 P2=3.30" Subcatchment 7S: Existing Conditions Hydrograph 0.16 0.15 cfs 0.14 -:Type IA 24 -hr 0.12 2 Year Rainfall=3.30" Runoff Area=1.800 ac w 0.1 -Runoff Volume=0.125 of U 3 0.08 -.Runoff Depth --0.84"" 0.06 Flow Length=234' Slope=0.0100 7' 0.04 Tc --25.1 min CN=69/0 5 10 15 20 25 30 35 40 45 50 Time (hours) —Runoff Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-2 Type IA 24 -hr 2 Year Rainfall=3.30" Prepared by A & O Engineering Printed 8/12/2021 HydroCADO 10.10-5a s/n 04993 © 2020 HydroCAD Software Solutions LLC Pace 8 Summary for Subcatchment 8S: Storage/Office Runoff = 0.03 cfs @ 7.98 hrs, Volume= 0.012 af, Depth= 3.07' Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-50.00 hrs, dt= 0.05 hrs Type IA 24 -hr 2 Year Rainfall=3.30" Area (sf) CN Description 2,024 98 Unconnected roofs HSG B 2,024 98 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (fee q (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment 8S: Storage/Office Hydrograph —Runoff Type IA 24 -hr 0 5 10 15 20 25 30 35 40 45 50 Time (hours) 0.03 2 Year Rainfall=3.30" Runoff Area=2,024 sf y 0.025 Runoff Volume=0.012 of 0.02- Runoff Depth=3.07" e Tc=10.0 min LL 0.015 CN=0198 0.01 0 5 10 15 20 25 30 35 40 45 50 Time (hours) Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-2 Type IA 24 -hr 2 YearRainfaf1=3.30" Prepared by A & O Engineering Printed 8/12/2021 HydroCAD@ 10.10-5a s/n 04993 © 2020 HydmCAD Software Solutions LLC Page 9 Summary for Subcatchment 14S: Parking Lot North Runoff = 0.08 cfs @ 7.98 hrs, Volume= 0.026 at Depth= 3.07' Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-50.00 hrs, dt= 0.05 hrs Type IA 24 -hr 2 Year Rainfall=3.30" Area (sf) CN Description 4,483 98 Paved parking, HSG B 4,483 98 100.00% Impervious Area To Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, 0 15 20 25 30 35 40 45 50 Time (hours) — Runoff Subcatchment 14S: Parking Lot North Hydrograph 0.08TGfs0.07 Type IA 24 -hr 2 Year Rainfall=3.30" 0.06Runoff Area=4,483 sf 0.05Runoff Volume=0.026 of Runoff Depth=3.07' e 0.04 Tc=10.0 min n nv CN=0/98 0 15 20 25 30 35 40 45 50 Time (hours) — Runoff Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-2 Type IA 24 -hr 2 Year Rainfall=3.30" Prepared by A & O Engineering Printed 8/12/2021 HydmCAD® 10.10-5a sm 04993 @ 2020 HydroCAD Software Solutions LLC Pace 10 Summary for Reach 13R: 10" Storm Inflow Area = 1.410 ac,100.00% Impervious, Inflow Depth = 0.46" for 2 Year event Inflow = 0.18 cfs @ 8.30 hm, Volume= 0.053 of Outflow, = 0.18 cfs @ 8.31 hrs, Volume= 0.053 af, Atten= 0%, Lag= 0.6 min Routing by Stor-Ind+Trans method, Time Span= 0.00-50.00 hrs, dt= 0.05 hrs Max. Velocity= 2.15 fps, Min. Travel Time= 0.4 min Avg. Velocity = 1.08 fps, Avg. Travel Time= 0.8 min Peak Storage= 4 cf @ 8.31 hrs Average Depth at Peak Storage= 0.18' , Surface Width= 0.68' Bank -Full Depth= 0.83' Flow Area= 0.5 sf, Capacity= 1.83 cfs 10.0" Round Pipe n= 0.011 Length=50.0' Slope=0.0050'/' Inlet Invert= 498.38', Outlet Invert= 498.13' Reach 13R: 10" Storm Hydrograph 0.2 0.18 cfs 0'18 Inflow Area=1.410 ac 0.16 Avg. Flow Depth=0.18' 0.14 Max Vel=2.15 fps 4 0.12 10.0" 3 0.1 Round Pipe LL 0 08- n=0.011 0.06 L=50.0' S=0.0050 T 0.04 Capacity=1.83 cfs 0 5 10 15 20 25 30 35 Time (hours) _ Inflow Outflow Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-2 Type IA 24 -hr 2 YearRainfa/1=3.30" Prepared by A & O Engineering Printed 8/12/2021 HydroCAD010.10-5a s/n 04993 ©2020 HydroCAD Software Solutions LLC Page 11 Summary for Pond 213: Rain Garden #1 Inflow Area = 0.560 ac,100.00% Impervious, Inflow Depth= 3.07" for 2 Year event Inflow = 0.41 cfs @ 7.98 hrs, Volume= 0.143 of Outflow = 0.08 cfs @ 10.99 hrs, Volume= 0.143 af, Atten= 80%, Lag= 180.6 min Discarded = 0.08 cfs @ 10.99 hrs, Volume= 0.143 of Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Routing by Stor-Ind method, Time Span= 0.00-50.00 hrs, dt= 0.05 hrs Peak Elev= 497.94'@ 10.99 hrs Surf.Area= 3,460 sf Storage= 1,705 cf Flood Elev= 498.53' Surf.Area= 3,678 sf Storage= 2,491 cf Plug -Flow detention time= 226.1 min calculated for 0.143 of (100% of inflow) Center -of -Mass det. time= 226.2 min ( 896.8 - 670.6 ) Volume Invert Avail.Storaoe Storaoe Descrintion #1 496.53' 2,581 cf Open Area (Prismatic)Listed below (Recalc) #2 495.53' 112 cf Growing Media (Prismatic) Listed below (Recalc) 1,122 cf Overall x 10.0% Voids #3 494.53' 245 cf Rock Chamber (Prismatic)Listed below (Recalc) 700 cf Overall x 35.0% Voids 2,938 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 496.53 700 0 0 498.83 1,544 2,581 2,581 Elevation Surf.Area Inc.Store Cum.Store _ (feet) (sq -ft) (cubicfeet)(cubic-feet) 495.53 700 0 0 496.53 1,544 1,122 1,122 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic feet) (cubic -feet) 494.53 700 0 0 495.53 700 700 700 Device Routing Invert Outlet Devices #1 Discarded 494.53' 1.050 in/hr Exfiltration over Surface area #2 Primary 498.63' 4.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Primary 498.00' 1.0" Vert. 1" Orifice C=0.600 Limited to weir flow at low heads Trded OutFlow Max=0.08 cfs @ 10.99 hrs HW=497.94' (Free Discharge) Exfillration (Exfiltration Controls 0.08 cfs) rimaryOutFlow Max=0.00 cfs @ 0.00 hrs HW=494.53' (Free Discharge) 2=Orifice/Grate ( Controls 0.00 cfs) 3=1" Orifice ( Controls 0.00 cfs) Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-2Type IA 24 -hr 2 Year Rainfall=3.30" Prepared by A & O Engineering Printed 8/12/2021 HydroCAD® 10.10-5a s/n 04993 Q2020 HydroCAD Software Solutions LLC Paae 12 Pond 2P: Rain Garden #1 Hydrograph 0.45 0.41 cfs —Inflow 0.4 '-Outflow Inflow Area=0.560 ac —Discarded 0.35 Peak Elev=497.94' —Primary 0.3 Storage=7,705 cf N 0.25 0 0.2 LL 0.15 0.08 cfs 0.1 10 15 20 25 30 Time (hours) Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-2 Type IA 24 -hr 2 Year Rainfall=3.30" Prepared by A & O Engineering Printed 8/12/2021 HydroCAD®10.10-5a s/n 04993 @ 2020 HydroCAD Software Solutions LLC Page 13 Summary for Pond 1213: Storm Planter #2 Inflow Area = 0.233 ac,100.00% Impervious, Inflow Depth = 3.07" for 2 Year event Inflow = 0.17 cfs @ 7.98 hrs, Volume= 0.060 of Outflow = 0.07 cfs @ 8.83 hrs, Volume= 0.060 af, Atten= 62%, Lag= 51.0 min Discarded = 0.07 cfs @ 8.83 hrs, Volume= 0.060 of Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Routing by Stor-Ind method, Time Span= 0.00-50.00 hrs, dt= 0.05 hrs Peak Elev= 498.98'@ 8.83 hrs Surf.Area= 1,074 sf Storage= 414 cf Flood Elev= 500.00' Surf.Area= 1,517 sf Storage= 862 cf Plug -Flow detention time= (not calculated: outflow precedes inflow) Center -of -Mass det. time= 70.9 min ( 741.4 - 670.6 ) Volume Invert Avail.Storage Storage Description #1 499.00' 438 cf Open Area Wall (Prismatic)Listed below (Recalc) #2 498.00' 321 cf Open Area (Prismatic)Listed below (Recalc) #3 497.00' 32 cf Growing Media (Prismatic)Listed below (Recalc) 321 cf Overall x 10.0% Voids #4 496.00' 71 cf Rock Chamber (Prismatic)Listed below (Recalc) 203 cf Overall x 35.0% Voids 862 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 499.00 438 0 0 500.00 438 438 438 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 498.00 203 0 0 499.00 438 321 321 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 497.00 203 0 0 498.00 438 321 321 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 496.00 203 0 0 497.00 203 203 203 Device Routing Invert Outlet Devices #1 Discarded 496.00' 2.250 in/hr Exfiltration over Horizontal area #2 Primary 499.80' 1.5" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-2 Type IA 24 -hr 2 Year Rainfall=3.30" Prepared by A & O Engineering Printed 8/1212021 HydroCAD®10.10-5a s/n 04993 @2020 HydroCAD Software Solutions LLC Page 14 Discarded OutFlow Max=0.06 cfs @ 8.83 hrs HW=498.98' (Free Discharge) L1=Exfiltration (Exfiltration Controls 0.06 cfs) rimary OutFlow Max=0.00 cfs @ 0.00 hrs HW=496.00' (Free Discharge) 2=OrificelGrate ( Controls 0.00 cfs) Pond 12P: Storm Planter #2 Hydrograph 0.18 0.17 cfs — Inflow — Outflow 0.16 Inflow Area=0.233 ac — Discarded 0.14 Peak Elev=498.98' — Primary Storage=414 cf 0.12 y w ' 0.1 3 LL 0.08 0.07 cfs 1 0.00 cfs I 0 5 10 15 20 25 30 35 40 45 Time (hours) Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - B-7-2 Type IA 24-hr 2 Year Rainfall=3.30" Prepared by A & O Engineering Printed 8/12/2021 HydroCAD® 10.10-5a s/n 04993 © 2020 HydroCAD Software Solutions LLC Page 15 Summary for Pond 16P: Dual Chamber CB Inflow Area = 0.149 ac,100.00% Impervious, Inflow Depth = 3.07" for 2 Year event Inflow = 0.11 cfs @ 7.98 hrs, Volume= 0.038 of Outnow = 0.11 cfs @ 7.98 hrs, Volume= 0.038 af, Atten= 0%, Lag= 0.0 min Primary = 0.11 cfs @ 7.98 hrs, Volume= 0.038 of Routing by Stor-Ind method, Time Span= 0.00-50.00 hrs, dt= 0.05 hrs Peak Elev= 497.24'@ 7.98 hrs Flood Elev= 499.00' Device Routing Invert Outlet Devices #1 Primary 497.00' 4.0" Vert. Orifice/Grate C=0.600 Limited to weir flow at low heads rimaryOutFIow Max=0.11 cfs @ 7.98 hrs HW=497.24' (Free Discharge) 1=Orifice/Grate (Orifice Controls 0.11 cfs @ 1.65 fps) Pond 16P: Dual Chamber CB Hydrograph 0-120.11 Cfs — Inflow 0.11 — Primary 0.1 Inflow Area=0.149 ac 0.09 Peak Elev=497.24' 0.08 0.07 0.06 a 0.05 0.04 0.03 0.02 0.01 0 0 5 10 15 20 25 30 35 40 45 50 Time (hours) Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-2 Type IA 24 -hr 2 YearRainfa/1=3.30" Prepared by A & O Engineering Printed 8/12/2021 HydroCAD® 10.10-5a s/n 04993 02020 HydroCAD Software Solutions LLC Page 16 Summary for Pond 17P: Storm Planter #1 Inflow Area = 0.467 ac,100.00% Impervious, Inflow Depth = 3.07" for 2 Year event Inflow = 0.34 cfs @ 7.98 hrs, Volume= 0.119 of Outflow = 0.20 cfs @ 8.35 hrs, Volume= 0.117 af, Atten= 42%, Lag= 22.5 min Discarded = 0.08 cfs @ 7.45 hrs, Volume= 0.102 of Primary = 0.12 cfs @ 8.35 hrs, Volume= 0.015 of Routing by Stor-Ind method, Time Span= 0.00-50.00 hrs, dt= 0.05 hrs Peak Elev= 499.84'@ 8.35 hrs Surf.Area= 1,783 sf Storage= 929 cf Flood Elev= 500.00' Surf.Area= 1,783 sf Storage= 1,010 cf Plug -Flow detention time= 108.6 min calculated for 0.117 of (98% of inflow) Center -of -Mass det. time= 96.0 min ( 766.6 - 670.6 ) Volume Invert Avail.Storage Storage Description #1 499.00' 510 cf Open Storage (Irregular)Listed below (Recalc) #2 498.00' 374 cf Open Area (Irregular)Listed below (Recalc) #3 497.00' 37 cf Growing Media (Irregular)Listed below (Recalc) 374 cf Overall x 10.0% Voids #4 496.00' 89 cf Rock Chamber (Irregular)Listed below (Recalc) 253 cf Overall x 35.0% Voids 1,010 cf Total Available Storage Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq -ft) (feet) (cubic -feet) (cubic -feet) (sq -ft) 499.00 510 97.7 0 0 510 500.00 510 97.7 510 510 608 Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq -ft) (feet) (cubic -feel) (cubic -feet) (sq -ft) 498.00 253 73.7 0 0 253 499.00 510 97.7 374 374 591 Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq -ft) (feet) (cubic -feet) (cubic -feet) (sq -ft) 497.00 253 73.7 0 0 253 498.00 510 97.7 374 374 591 Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq -ft) (feet) (cubic -feet) (cubic -feet) (sq -ft) 496.00 253 73.7 0 0 253 497.00 253 73.7 253 253 327 Device Routing Invert Outlet Devices #1 Discarded 496.00' 2.250 in/hr Exfiltration over Horizontal area from 496.00' - 499.00' Excluded Horizontal area = 253 sf #2 Primary 499.80' 4.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Primary 499.20' 1.5" Vert. 1.5" Orifice C=0.600 Limited to weir flow at low heads Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-2 Type IA 24 -hr 2 Year Rainfall=3.30" Prepared by A & O Engineering Printed 8/12/2021 HydroCAD010.10-5a s/n 04993 @2020 HydroCAD Software Solutions LLC Page 17 #4 Primary 499.20' 1.5" Vert. 1.5" Orifice C=0.600 Limited to weir flow at low heads Discarded OutFlow Max=0.08 cfs @ 7.45 hrs HW=499.00' (Free Discharge) L1=Exfiltration (Exfiltration Controls 0.08 cfs) rinry OutFlow Max=0.12 cfs @ 8.35 hrs HW=499.84' (Free Discharge) 2=Orifice/Grate (Weir Controls 0.03 cfs @ 0.66 fps) 3=1.5" Orifice (Orifice Controls 0.04 cfs @ 3.66 fps) =1.5" Orifice (Orifice Controls 0.04 cfs @ 3.66 fps) 0.34 cfs Pond 17P: Storm Planter #1 Hydrograph 0.20 Inflow Area=0.467 ac 0.2 cfs, _ 3 —Discarded 0 —Primary W 0.15 0.12 cfs 0.1 0.08 fs Pond 17P: Storm Planter #1 Hydrograph 0 5 10 15 20 25 30 35 40 45 50 Time (hours) — Inflow Inflow Area=0.467 ac — Outflow —Discarded Peak Elev=499.84' —Primary Storage=929 cf 0 5 10 15 20 25 30 35 40 45 50 Time (hours) Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-202 Type IA 24 -hr WQ Rainfall=0.83" Prepared by A & O Engineering Printed 8/12/2021 HydroCAD® 10.10-5a s/n 04993 @2020 HydroCAD Software Solutions LLC Pace 18 Summary for Subcatchment 1S: Parking Lot Runoff = 0.09 cfs @ 7.98 hrs, Volume= 0.029 af, Depth= 0.63" Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-50.00 hrs, dt= 0.05 hrs Type IA 24 -hr WQ Rainfall=0.83" Area (sf) CN Description 24,403 98 Paved parking HSG B 24,403 98 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment 1S: Parking Lot Hydrograph —Runoff 0 5 10 15 20 25 30 35 40 45 50 Time (hours) 0.08 Type IA 24 -hr WQ Rainfall=0.83" 0.07 Runoff Area=24,403 sf 0.06 Runoff Volume=0.029 of 0.05 Runoff Depth=0.63" e Tc=10.0 min LL 0.04 CN=0198 0.03 0.02 0.01 0 5 10 15 20 25 30 35 40 45 50 Time (hours) Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-202 Type IA 24 -hr WQ Rainfall=0.83" Prepared by A & 0 Engineering Printed 8/12/2021 HydroCAD® 10.10-5a s/n 04993 @2020 HydroCAD Software Solutions LLC Page 19 Summary for Subcatchment 3S: Apartment #3 Runoff = 0.04 cfs @ 7.98 hrs, Volume= 0.012 af, Depth= 0.63" Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-50.00 hrs, dt= 0.05 hrs Type IA 24 -hr WQ Rainfall=0.83" 10 15 20 25 30 35 40 Time (hours) Area (sf) CN Description 9,530 98 Unconnected roofs, HSG B 641 98 Unconnected pavement, HSG B 10,171 98 Weighted Average 10,171 98 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (fUsec) (cfs) 10.0 Direct Entry, Subcatchment 3S: Apartment #3 Hydrograph 0.04 0.04 cfs — Runoff 0.035 Type IA 24 -hr 0.03 WQ Rainfall=0.83" Runoff Area=10,171 sf 0.025 Runoff Volume=0.012 of Runoff Depth=0.63" e 0.02-.Tc=10.0 min " 0.015 CN=0/98 10 15 20 25 30 35 40 Time (hours) Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-202 Type IA 24 -hr WQ Rainfall=0.83" Prepared by A & O Engineering Printed 8/12/2021 HydroCAD®10.10-5a s/n 04993 @2020 HydraGAD Software Solutions LLC Pace 20 Summary for Subcatchment 4S: Apartment #2 Runoff = 0.04 cfs @ 7.98 hrs, Volume= 0.012 af, Depth= 0.63" Runoff by SBUH method, Split Perviousllmperv., Time Span= 0.00-50.00 hrs, dt= 0.05 hrs Type IA 24 -hr WQ Rainfall=0.83" Area (sf) CN Description 9,530 98 Unconnected roofs, HSG B 641 98 Unconnected pavement HSG B 10,171 98 Weighted Average 10,171 98 100.00% Impervious Area Tc Length Slope Velocity Capacity Description Direct entry, Subcatchment 4S: Apartment #2 Hydrograph —Runoff 0 5 10 15 20 25 30 35 40 45 50 Time (hours) U.U00 Type IA 24 -hr 0.03 WQ Rainfall=0.83" Runoff Area=10,171 sf N 0.025 Runoff Volume=0.012 of Runoff Depth=0.63" c 0.02-:Tc=10.0 min 0.015 CN=0/98 0.01 0 5 10 15 20 25 30 35 40 45 50 Time (hours) Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-202 Type IA 24 -hr WQ Rainfall=0.83" Prepared by A 8, 0 Engineering Printed 8/12/2021 HydroCAD@ 10.10-5a s/n 04993 @ 2020 HvdroCAD Software Solutions LLC Page 21 Summary for Subcatchment 5S: Apartment #1 Runoff = 0.04 cfs @ 7.98 hrs, Volume= 0.012 af, Depth= 0.63" Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-50.00 hrs, dt= 0.05 hrs Type IA 24 -hr WQ Rainfall=0.83" Area (sf) CN Description 9,530 98 Unconnected roofs, HSG B 641 98 Unconnected pavement, HSG B 10,171 98 Weighted Average 10,171 98 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (f /ft) (fUsec) (cfs) 10.0 Direct Entry, Subcatchment 5S: Apartment #1 Hydrograph — Runoff 0.r s I 0 5 10 15 20 25 30 35 40 45 50 Time (hours) ' Type IA 24 -hr 0.03 WQ Rainfall=0.83" Runoff Area=10,171 sf 0.025. Runoff Volume=0.012 of w Runoff Depth=0.63" 0.02 Tc=10.0 min 0 0.015 CN=0198 0.01 0.r s I 0 5 10 15 20 25 30 35 40 45 50 Time (hours) Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-202 Type IA 24 -hr NQ Rainfall=0.83" Prepared by A & O Engineering Printed 8/12/2021 HydroCAD®10 10-5a stn 04993 © 2020 HydroCAD Software Solutions LLC Page 22 Summary for Subcatchment 7S: Existing Conditions Runoff = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af, Depth= 0.00" Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-50.00 hrs, dt= 0.05 hrs Type IA 24 -hr WO Rainfall=0.83" Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ftlsec) (cfs) 25.1 234 0.0100 0.16 Sheet Flow, Grass: Short n=0.150 P2=3.30" Subcatchment 7S: Existing Conditions Hydrograph — Runoff Type IA 24 -hr WQ Rainfall=0.83" Runoff Area=1.800 ac Runoff Volume=0.000 of U 3 Runoff Depth=0.00" .2 Flow Length=234' Slope=0.0100 '1' Tc=25.1 min CN=69/0 20 25 30 35 40 45 50 Time (hours) Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-202 Type IA 24 -hr WQ Rainfall=0.83" Prepared by A & O Engineering Printed 8/12/2021 HydroCAD® 10.10-5a s/n 04993 @2020 HydroCAD Software Solutions LLC Page 23 Summary for Subcatchment 8S: Storage/Office Runoff = 0.01 cfs @ 7.98 hrs, Volume= 0.002 af, Depth= 0.63" Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-50.00 hrs, dt= 0.05 hrs Type IA 24 -hr WQ Rainfall=0.83" Area (sf) CN Description 2,024 98 Unconnected roofs HSG B 2,024 98 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment 8S: Storage/Office Hydrograph 0.001 0 25 30 35 40 45 50 Time (hours) —Runoff Type IA 24 -hr 0.006, WQ Rainfall=0.83" Runoff Area=2,024 sf 0.005 -.Runoff Volume=0.002 of Runoff Depth=0.63" 3 0.004 Tc=10.0 min g LL n nns CN=0/98- 0.001 0 25 30 35 40 45 50 Time (hours) —Runoff Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-202 Type IA 24 -hr WQ Rainfall=0.83" Prepared by A & O Engineering Printed 8/12/2021 HydroCAD® 10.10-5a s/n 04993 @2020 HydroCAD Software Solutions LLC Pace 24 Summary for Subcatchment 145: Parking Lot North Runoff = 0.02 cfs @ 7.98 hrs, Volume= 0.005 af, Depth= 0.63" Runoff by SBUH method, Split Pervious/Imperv., Time Span= 0.00-50.00 hrs, dt= 0.05 hrs Type IA 24 -hr WQ Rainfall=0.83" Area (sf) CN Description 4,483 98 Paved parking HSG B 4,483 98 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (Rift) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment 14S: Parking Lot North Hydrograph 0.02 cfs 0.016 Type IA 24 -hr 0.014 WQ Rainfall=0.83" 0.012 Runoff Area=4,483 sf Runoff Volume=0.005 of u 0.01 Runoff Depth=0.63" 0 0.008 Tc=10.0 min LL CN=0/98 0.006 0.004 0 5 10 15 20 25 30 35 40 45 50 Time (hours) — Runoff Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-202 Type IA 24 -hr WQ Rainfall=0.83" Prepared by A & O Engineering Printed 8/12/2021 HydmCADOO 10.10-5a s/n 04993 @ 2020 HydroCAD Software Solutions LLC Page 25 Summary for Reach 13R: 10" Storm Inflow Area = 1.410 ac,100.00% Impervious, Inflow Depth = 0.07" for WQ event Inflow = 0.02 cfs @ 7.98 hrs, Volume= 0.008 of Outflow = 0.02 cfs @ 8.00 hrs, Volume= 0.008 af, Atten= 1 %, Lag= 0.7 min Routing by Star-Ind+Trans method, Time Span= 0.00-50.00 hrs, dt= 0.05 hrs Max. Velocity= 1.16 fps, Min. Travel Time= 0.7 min Avg. Velocity = 0.66 fps, Avg. Travel Time= 1.3 min Peak Storage= 1 cf @ 7.99 hrs Average Depth at Peak Storage= 0.07' , Surface Width= 0.45' Bank -Full Depth= 0.83' Flow Area= 0.5 sf, Capacity= 1.83 cfs 10.0" Round Pipe n= 0.011 Length= 50.0' Slope= 0.0050'/' Inlet Invert= 498.38', Outlet Invert= 498.13' 0 Reach 13R: 10" Storm Hydrograph 0.024- 0.02 cfs 0.022 - Inflow Area=1.410 ac 0.02= Avg. Flow Depth --0.07' 0.018 Max Vel=1.16 fps 0.016 0.014: 10.0" e 0.012-- Round Pipe LL 0.01 n=0.011 0.008 L=50.0' 0.006 S=0.0050 T 0.004 Capacity=1.83 cfs 10 25 30 35 40 45 50 Time (hours) Inflow Outflow Designed 6y: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-202 Type IA 24 -hr WQ Rainfall=0.83" Prepared by A & O Engineering Printed 8/12/2021 HydroCAD010.10-5a s/n 04993 @2020 HydroCAD Software Solutions LLC Page 26 Summary for Pond 2P: Rain Garden #1 Inflow Area = 0.560 ac,100.00% Impervious, Inflow Depth= 0.63" for WQ event Inflow = 0.09 cfs @ 7.98 hrs, Volume= 0.029 of Outflow = 0.03 cfs @ 9.29 hrs, Volume= 0.029 af, Atten= 69%, Lag= 78.2 min Discarded = 0.03 cfs @ 9.29 hrs, Volume= 0.029 of Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Routing by Stor-Ind method, Time Span= 0.00-50.00 hrs, dt= 0.05 hrs Peak Elev= 495.53' @ 9.29 hrs Surf.Area= 700 sf Storage= 244 cf Flood Elev= 498.53' Surf.Area= 3,678 sf Storage= 2,491 cf Plug -Flow detention time= 144.8 min calculated for 0.029 of (100% of inflow) Center -of -Mass det. time= 144.7 min ( 874.5 - 729.9 ) #1 496.53' 2,581 cf Open Area (Prismatic)Listed below (Recalc) #2 495.53' 112 cf Growing Media (Prismatic)Listed below (Recalc) 1,122 cf Overall x 10.0% Voids #3 494.53' 245 cf Rock Chamber (Prismatic)Listed below (Recalc) 700 cf Overall x 35.0% Voids 2,938 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 496.53 700 0 0 498.83 1,544 2,581 2,581 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 495.53 700 0 0 496.53 1,544 1,122 1,122 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feel) 494.53 700 0 0 495.53 700 700 700 Device Routing Invert Outlet Devices #1 Discarded 494.53' 1.050 in/hr Exfiltration over Surface area #2 Primary 498.63' 4.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Primary 498.00' 1.0" Vert. 1" Orifice C=0.600 Limited to weir flow at low heads MDiscarded OutFlow Max=0.02 cfs @ 9.29 hrs HW=495.53' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.02 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=494.53' (Free Discharge) L2=Orifice/Grate ( Controls 0.00 cfs) 3=1" Orifice ( Controls 0.00 cfs) Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-202 Type IA 24 -hr WO Rainfall=0.83" Prepared by A & 0 Engineering Printed 8/12/2021 HydroCAD0 10.10-5a s/n 04993 02020 HydroCAD Software Solutions LLC Page 27 Pond 2P: Rain Garden #1 Hydrograph 0.09 0.09 cfs M 0.08 Inflow Area=0.560 ac 0.07. Peak Elev=495.53' Storage=244 cf ?0 25 30 35 40 45 50 Time (hours) 0.06 0.05 3 u 0.04 0.03 0.03 ?0 25 30 35 40 45 50 Time (hours) Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-202 Type IA 24 -hr NQ Rainfall=0.83" Prepared by A & O Engineering Printed 8/12/2021 HydroCAD®10.10-5a s/n 04993 © 2020 HydroCAD Software Solutions LLC Page 28 Summary for Pond 12P: Storm Planter #2 Inflow Area = 0.233 ac, 100.00% Impervious, Inflow Depth= 0.63" for WQ event Inflow = 0.04 cfs @ 7.98 hrs, Volume= 0.012 of Outflow = 0.01 cfs @ 9.01 hrs, Volume= 0.012 af, Atten= 63%, Lag= 61.7 min Discarded = 0.01 cfs @ 9.01 hrs, Volume= 0.012 of Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Routing by Stor-Ind method, Time Span= 0.00-50.00 hrs, dt= 0.05 hrs Peak Elev= 496.97' @ 9.01 hrs Surf.Area= 203 sf Storage= 69 cf Flood Elev= 500.00' Surf.Area= 1,517 sf Storage= 862 cf Plug -Flow detention time= 39.4 min calculated for 0.012 of (100% of inflow) Center -of -Mass det. time= 39.4 min ( 769.3 - 729.9 ) #1 499.00' 438 cf Open Area Wall (Prismatic)Listed below (Recalc; #2 498.00' 321 cf Open Area (Prismatic)Listed below (Recalc) #3 497.00' 32 cf Growing Media (Prismatic)Listed below (Recalc) 500.00 438 438 321 cf Overall x 10.0% Voids #4 496.00' 71 cf Rock Chamber (Prismatic)Listed below (Recalc) Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 499.00 438 0 0 500.00 438 438 438 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feel) 498.00 203 0 0 499.00 438 321 321 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 497.00 203 0 0 498.00 438 321 321 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 496.00 203 0 0 497.00 203 203 203 Device Routing Invert Outlet Devices #1 Discarded 496.00' 2.250 inlhr Exfiltration over Horizontal area #2 Primary 499.80' 1.5" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-202 Type IA 24 -hr NQ Rainfall=0.83" Prepared by A & 0 Engineering Printed 8/12/2021 ydroCAD®10.10-5a s/n 04993 © 2020 HydroCAD Software Solutions LLC Pace 29 Discarded OutFlow Max=0.01 cfs @ 9.01 hrs HW=496.97' (Free Discharge) L1=Exfillration (Exfiltration Controls 0.01 cfs) rimary OutFlow Max=0.00 cfs @ 0.00 hrs HW=496.00' (Free Discharge) 2=0rifice/Grate ( Controls 0.00 cfs) y U.U2 F U 3 O.0 0 0.01 0.01 Pond 1213: Storm Planter #2 Hydrograph 10 25 30 35 40 45 50 Time (hours) — Inflow — Outflow Inflow Area=0.233 ac — Discarded Peak Elev=496.97' — Primary Storage=69 cf 10 25 30 35 40 45 50 Time (hours) Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-202 Type lA 24 -hr WQ Rainfall=0.83" Prepared by A & 0 Engineering Printed 8/12/2021 HydroCAD®10.10-5a sin 04993 @ 2020 HydroCAD Software Solutions LLC Page 30 Summary for Pond 16P: Dual Chamber CB Inflow Area = 0.149 ac,100.00% Impervious, Inflow Depth= 0.63" for WQ event Inflow = 0.02 cis @ 7.98 hrs, Volume= 0.008 of Outflow = 0.02 cfs @ 7.98 hrs, Volume= 0.008 af, Atten= 0%, Lag= 0.0 min Primary = 0.02 cfs @ 7.98 hrs, Volume= 0.008 of Routing by Stor-Ind method, Time Span= 0.00-50.00 hrs, dt= 0.05 hrs Peak Elev= 497.10'@ 7.98 hrs Flood Elev= 499.00' Device Routing Invert Outlet Devices #1 Primary 497.00' 4.0" Vert. Orifice/Grate C=0.600 Limited to weir flow at low heads rlmaryOutFlow Max=0.02 cfs @ 7.98 hrs HW=497.10' (Free Discharge) =Orifice/Grate (Orifice Controls 0.02 cfs @ 1.07 fps) Pond UP: Dual Chamber CB Hydrograph 0.0240.02 Cfs — Inflow 0.022 Inflow Area=0.149 ac — Primary 0.02 Peak Elev=497.10' 0.018 w 0.016 0.014 ?1: 0.012 LL 0.01 0 5 10 15 20 25 30 35 40 45 50 Time (hours) Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-202 Type IA 24 -hr WQ Rainfall=0.83" Prepared by A & 0 Engineering Printed 8/12/2021 HydroCADO 10.10-5a s/n 04993 @ 2020 HydroCAD Software Solutions LLC Page 31 Summary for Pond 17P: Storm Planter #1 Inflow Area = 0.467 ac, 100.00% Impervious, Inflow Depth= 0.63" for WQ event Inflow = 0.07 cfs @ 7.98 hrs, Volume= 0.024 of Outflow = 0.04 cfs @ 8.37 hrs, Volume= 0.022 af, Atlen= 42°%, Lag= 23.3 min Discarded = 0.04 cfs @ 8.37 hrs, Volume= 0.022 of Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Routing by Stor-Ind method, Time Span= 0.00-50.00 hrs, dt= 0.05 hrs Peak Elev= 498.15' @ 8.37 hrs Surf.Area= 1,049 sf Storage= 167 cf Flood Elev= 500.00' Surf.Area= 1,783 sf Storage= 1,010 cf Plug -Flow detention time= 106.5 min calculated for 0.022 of (92% of inflow) Center -of -Mass det. time= 51.2 min ( 781.1 - 729.9 ) Volume Invert Avail.Storage Storage Description #1 499.00' 510 cf Open Storage (Irregular)Listed below (Recalc) #2 498.00' 374 cf Open Area (Imegular)Listed below (Recalc) #3 497.00' 37 cf Growing Media (Irregular) Listed below (Recalc) 510 500.00 510 374 of Overall x 10.0% Voids 510 #4 496.00' 89 cf Rock Chamber (Irregular)Listed below (Recalc) 1,010 Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq -ft) (feet) (cubic -feet) (cubic -feet) (sq -ft) 499.00 510 97.7 0 0 510 500.00 510 97.7 510 510 608 Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq -ft) (feet) (cubic -feet) (cubic -feet) (sq -ft) 498.00 253 73.7 0 0 253 499.00 510 97.7 374 374 591 Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq -ft) (feet) (cubic -feet) (cubic -feet) (sq -ft) 497.00 253 73.7 0 0 253 498.00 510 97.7 374 374 591 Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq -ft) (feet) (cubic -feet) (cubic -feet) (sq -ft) 496.00 253 73.7 0 0 253 497.00 253 73.7 253 253 327 Device Routing Invert Outlet Devices #1 Discarded 496.00' 2.250 in/hr Exfiltration over Horizontal area from 496.00' - 499.00' Excluded Horizontal area = 253 sf #2 Primary 499.80' 4.0" Hertz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Primary 499.20' 1.5" Vert. 1.5" Orifice C=0.600 Limited to weir flow at low heads Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-202 Type IA 24 -hr WQ Rainfall=0.83" Prepared by A & O Engineering Printed 8/12/2021 HydroCAD@ 10.10-5a s/n 04993 @2020 HydroCAD Software Solutions LLC Paae 32 #4 Primary 499.20' 1.5" Vert. 1.5" Orifice C=0.600 Limited to weir Flow at low heads Discarded OutF[ow Max=0.04 cfs @ 8.37 hrs HW=498.15' (Free Discharge) 1=Exfillration (Exfiltration Controls 0.04 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 bra HW=496.00' (Free Discharge) 2=Orifice/Grate ( Controls 0.00 cfs) 3=1.5" Orifice ( Controls 0.00 cfs) =1.5" Orifice ( Controls 0.00 cfs) Pond 17P: Storm Planter #1 Hydrograph 10.00 cfs r 0 5 10 15 20 25 30 35 40 45 50 Time (hours) 0.08 0.07 cfs — Inflow 0.07 -'Inflow Area=0.467 ac — Outflow —Discarded 0.06 Peak Elev=498.15' —primary Storage=167 cf " 0.05 0.04 cfs U 3 0.04 0 a n nil 10.00 cfs r 0 5 10 15 20 25 30 35 40 45 50 Time (hours) Designed By: DOM, SDM Ridgeview Apartements Storm Analysis - SDM - 8-7-2021 Table of Contents Prepared by A & O Engineering Printed 8/12/2021 HydroCAD& 10.10-5a sm 04993 @2020 HydmCAD Software Solutions LLC TABLE OF CONTENTS Proiect Reports 1 Routing Diagram 2 Rainfall Events Listing (selected events) 2 Year Event 3 Subcat 1S: Parking Lot 4 Subcat 3S: Apartment#3 5 Subcat 4S: Apartment #2 6 Subcat SS: Apartment#1 7 Subcat 7S: Existing Conditions 8 Subcat 8S: Storage/Office 9 Subcat 145: Parking Lot North 10 Reach 13R: 10" Storm 11 Pond 2P: Rain Garden #1 13 Pond 12P: Storm Planter #2 15 Pond 16P: Dual Chamber CB 16 Pond 17P: Storm Planter #1 WO Event 18 Subcat 1S: Parking Lot 19 Subcat 3S: Apartment #3 20 Subcat 4S: Apartment #2 21 Subcat 5S: Apartment#1 22 Subcat 7S: Existing Conditions 23 Subcat BS: Storage/Office 24 Subcat 14S: Parking Lot North 25 Reach 13R: 10" Storm 26 Pond 2P: Rain Garden #1 28 Pond 12P: Storm Planter #2 30 Pond 16P: Dual Chamber CB 31 Pond 17P: Storm Planter #1 Geotechnical Engineering Report Ridgeview Gardens 5050 Main Street Springfield, Oregon Prepared for: Ridgeview Gardens, LLC 7070 SW Baylor Street Portland, Oregon 97223 September 22, 2020 PBS Project 73415.002 OZ PBS 4412 5 CORBETT AVENUE PORTLAND, OR 97239 503.248.1939 MAIN 866 727 0140 FAX PESUSA. COM Geotechnical Engineering Report Ridgeview Gardens 5050 Main Street Springfield, Oregon Prepared for: Ridgeview Gardens, LLC 7070 SW Baylor Street Portland, Oregon 97223 September 22, 2020 PBS Project 73415.002 Prepared by: -[:) A--b-EL(� L - Dave Eibert, GIT Staff Geologist ® 2020 PBS Engineering and Environmental Inc. Reviewed by: n 11140, aA g�1'r.- 63eeoPE � OUGON N 9�'1rry 15 9YgN VV FRENAL RATE: 6/30/2022 Ryan White, PE, GE Principal/Geotechnical Engineering Group Manager AAI? S (CIP P[TT LV CN II[ Kill PTI!Kin nn 07>30 . ena ono too. Kien lnl . eee vi♦ ni en eno . euaa I . 11M Geri Engineering Report Ni Gardens RidgevIew Gardens, LLC Springfield, Oregon Table of Contents 3 CONCLUSIONS AND RECOMMENDATIONS ................................................................................................ 5 3.1 Geotechnical Design Considerations ............. ____ ..................................................................................... ....................... 5 3.2 Shallow Foundations .... ____ .................................................................. ... __ ......................................................... 5 8 3.2.1 Minimum Footing Widths and Design Bearing Pressure .................................. ...................................... 5 ... __ ................ 8 3.2.2 Footing Embedment Depths ............................................................................................................................ - 5 ..... _ ...... ............................ 9 3.2.3 Footing Preparation ......................... - ....................................................... ...................... ...... _ .................................. 5 9 3.2.4 Lateral Resistance .................................................................................................................................................... 5 3.3 Floor Slabs ........................................................... ................................................................. _ ..... .................. 6 3.4 Seismic Design Considerations .................................................... _ ................. ____ ............................................ ____ 6 _ ...................... ............ 10 3.4.1 Code -Based Seismic Design Parameters. ...................................... _ .......... _ ....................................... 6 22, 2020 3.4.2 Liquefaction Potential....... ..................................................... ....................................................................... ___ 7 3.5 Ground Moisture .......................................................................................................... _ .......... _ .... _ ....................................... 7 3.5.1 General .................. ............................................................ ____ ____ ................................................................. 7 3.5.2 Perimeter Footing Drains ............ __ ................. _ ....................................................................................................... 7 3.5.3 Vapor Flow Retarder. ..................................................... ............................................................7 3.6 Pavement Desian ...................................... ___ ............................................................................. ............................................. 7 4 CONSTRUCTION RECOMMENDATIONS ...................................................................................................... 8 4.1 Site Preparation.. ............................................................................ ___ .......................................................... ........................8 4.1.1 Proorfrolling/Subgrade Verification ................................................. ...................................................................... 8 4.1.2 Wet/Freezing Weather and Wet Soil Conditions ...................................................... ... __ ................ 8 4.1.3 Dry Weather Conditions ... _ ................................................................ .... ____ ..... _ ...... ............................ 9 4.1.4 Compacting Test Pit Locations ................... _ ___ .......................................................................... 9 4.2 Excavation ................................... ......... .......... __ ................................................... ___ .............. ........................ 9 4.3 Structural Fill _ ............................................................ _ ............................................................................ __ ......................... 9 4.3.1 On -Site Soil ........................................... ____ ....................................... _ ...................... _ ...................... ............ 10 22, 2020 ONSeptember P B S paSeptemberoj.d 73415.002 Geotechnical Engineering Report Rldgeview Gardens Ridgeview Gardens, LLC Sprinqfield, Oregon 4.3.2 Borrow Material ................ .............................. .......... ....---- ................................................. —........................... ......... 10 4.3.3 Select Granular Fill...................................................... --.......---- ... ..................................................... 10 4.3.4 Crushed Aggregate Base........................................................................ .........10 4.3.5 Utility Trench Backfill ............................. —..... —......................................................................................................... 10 4.3.6 Stabilization Material................................................................................................................................................. 11 5 ADDITIONAL SERVICES AND CONSTRUCTION OBSERVATIONS............................................................ 11 6 LIMITATIONS................................................................................................................................................ 11 7 REFERENCES.................................................................................................................................................. 13 Supporting Data TABLES Table 1. Infiltration Test Results Table 2. USDA Hydrologic Soil Group Parameters Table 3. 2019 OSSC Seismic Design Parameters Table 4. Minimum AC Pavement Sections FIGURES Figure 1. Vicinity Map Figure 2. Site Plan APPENDICES Appendix A: Field Explorations Table A-1. Terminology Used to Describe Soil Table A-2. Key to Test Pit and Boring Log Symbols Figures Al—A8. Logs for Test Pits TP -1 through TP -8 Appendix B: Laboratory Testing Figure B1. Atterberg Limits Test Results Figure B2. Summary of Laboratory Data PBS September 22, 2020 . J ii PBS Proiec[]3415002 Geotechnical Engineering Report Ridgeview Gardens Ridgeview Gardens, LLC Springfield, Oregon 1 INTRODUCTION 1.1 General This report presents results of PBS Engineering and Environmental Inc. (PBS) geotechnical engineering services for the proposed housing development located at SOSO Main Street in Springfield, Oregon (site). The general site location is shown on the Vicinity Map, Figure 1. The locations of PBS' explorations in relation to existing and proposed site features are shown on the Site Plan, Figure 2. 1.2 Purpose and Scope The purpose of PBS' services was to develop geotechnical design and construction recommendations in support of the planned new development. This was accomplished by performing the following scope of services. 1.2.1 Literature and Records Review PBS reviewed various published geologic maps of the area for information regarding geologic conditions and hazards at or near the site. 1.2.2 Subsurface Explorations PBS excavated eight test pits within the proposed development site to depths of up to 12 feet below the existing ground surface (bgs). The test pits were logged and representative soil samples collected by a member of the PBS geotechnical engineering staff. Interpreted test pit logs are included as Figures Al through All in Appendix A, Field Explorations. 1.2.3 Field Infiltration Testing Two open -hole, failing -head field infiltration tests were completed in test pits TP -2 and TP -7 at depths of 5.5 and 6.0 feet bgs, respectively. Infiltration testing was monitored by PBS geotechnical engineering staff. 1.2.4 Soils Testing Soil samples were returned to our laboratory and classified in general accordance with the Unified Soil Classification System (ASTM D2487) and/or the Visual -Manual Procedure (ASTM D2488). Laboratory tests included natural moisture contents, grain -size analyses, and Atterberg limits. Laboratory test results are included in the exploration logs in Appendix A, Field Explorations; and in Appendix B, Laboratory Testing. 1.2.5 Geotechnical Engineering Analysis Data collected during the subsurface exploration, literature research, and testing were used to develop site- specific geotechnical design parameters and construction recommendations. 1.2.6 Report Preparation This Geotechnical Engineering Report summarizes the results of our explorations, testing, and analyses, including information relating to the following: • Field exploration logs and site plan showing approximate exploration locations • Laboratory test results • Infiltration test results • Groundwater considerations • Shallow foundation design recommendations: c Minimum embedment o Allowable bearing pressure PBS PBS 22, 2020 0 '+YK•\/ 1 S Projec[73415.002 Geotechnical Engineering Report Ridgeview Gardens Ridgeview Gardens, LLC Springfield, Oregon o Estimated settlement (total and differential) o Sliding coefficient Earthwork and grading, cut, and fill recommendations: o Structural fill materials and preparation, and reuse of on-site soils o Wet weather considerations o Utility trench excavation and backfill requirements o Temporary and permanent slope inclinations • Seismic design criteria in accordance with the 2019 Oregon Structural Specialty Code (OSSC) • Slab and pavement subgrade preparation recommendations • Recommended asphalt concrete (AC) pavement sections 1.3 Project Understanding PBS understands current plans include developing the approximately 2 -acre site with three, 3 -story, wood - frame apartment buildings, a single -story office/storage building, and associated paved parking areas and utilities. Preliminary plans include disposing of stormwater through shallow drywells. 2 SITE CONDITIONS 2.1 Surface Description The site is a trapezoidal parcel of land, extended to the north along its western margin, and is currently sparsely vegetated. It is bordered to the north by Riverbend Elementary School and a local church, to the south and west by commercial businesses, and to the east by residential properties. The site is accessed by a north - south driveway between the two southern businesses off of Main Street. Review of available Google Earth elevation data shows that the site is relatively flat, with elevations ranging from approximately S00 to 502 feet above mean sea level (amsl) (DOGAMI, 2020a). The surrounding area is generally flat in all directions except where shallow river terraces generated from river meanders of the McKenzie, Middle, and Coastal forks of the Willamette River have reworked valley sediments. Outside of these river valleys the deeply eroded foothills of the Cascade mountains rise from the valley margins. 2.2 Geologic Setting The site is located along the southern margin of the Willamette Valley, a tectonic depression within the physiographic province of the Puget -Willamette Lowland that separates the Cascade Range from the Coast Range, and extends from the Puget Sound, Washington to Eugene, Oregon (Yeats of al., 1996). The Puget - Willamette Lowland is situated along the Cascadia Subduction Zone (CSZ) where oceanic rocks of the Juan de Fuca Plate are subducting beneath the North American Plate, resulting in deformation and uplift of the Coast Range and volcanism in the Cascade Range. Northwest -trending faults accommodating clockwise rotation of the North American Plate are found throughout the Puget -Willamette lowland (Brocher et al., 2017; USES, 2020). Structural features of the southern Willamette Valley include the north-northeast oriented Eocene age Harrisburg anticline, numerous northwest- and northeast -trending normal faults, as well as northwest - trending strike slip faults (McClaughry at al., 2010). Similar structures exist outside of the valley and in the surrounding Coast Range and Cascade Range. These structures are responsible for deforming and offsetting basement rocks and are recognized as inactive tectonic features. �� September 22, 2020 2 Pas Proiect 73415 002 Geotechnical Engineering Report Ridgeview Gardens Ridgeview Gardens, LLC Springfield, Oregon The Willamette Valley forms a broad alluvial basin, with the Willamette River draining northward along the axis of the valley. Extensive valley infilling and catastrophic flooding related to the Missoula Floods during the Quaternary has subsequently buried older Oligocene and Eocene sedimentary and volcanic basement rocks and concealed many of the structural features throughout the valley CWiley, 2006). Willamette River tributaries exiting the Coast Range and Cascade Range have contributed to terrace formations and broad alluvial fans protruding from range fronts into the valley. The Willamette and McKenzie Rivers enter the Willamette Valley south and east of the city of Springfield, respectively, and form a confluence north of the city of Eugene. These rivers continue to deposit sediments and reworked older sediments throughout much of the Eugene/Springfield area. Both rivers are positioned within prominent meander belts. Modern flood plains are readily distinguishable within the DOGAMI LiDAR data and meandered freely prior to urban development. The southern Willamette Valley terminates south of Springfield and Eugene where the Cascade and coastal mountains converge. Along the eastern margin of the valley, Oligocene volcanic rocks of the Cascade mountains begin to emerge from youngervalley sediments that are interfingered with alluvial fans and debris fans formed from Cascade detritus. West of the Willamette Valley, accreted Eocene to Oligocene deep marine sedimentary sequences and subaerial volcanism is encountered. 2.2.1 Local Geology The site is mapped as underlain by Quaternary terrace and fan deposits (McClaughry et al., 2010). The terrace and fan deposits are described as deeply dissected, unconsolidated to semi -consolidated deposits of gravel, sand, silt, and clay from the upper alluvial terraces along the Willamette, Coast Fork of the Willamette, and McKenzie Rivers. These deposits form a broad, once continuous, dissected fan that stretches from the southern Willamette Valley to the Santiam River in the central Willamette Valley. 2.3 Subsurface Conditions The site was explored by excavating eight test pits, designated TP -1 through TP -8, to depths of up to 12 feet bgs. The excavation was performed by Dan J. Fischer Excavating, Inc., of Forest Grove, Oregon, using a Case 508 Super -N backhoe equipped with a 24 -inch toothed bucket. PBS has summarized the subsurface units as follows: FILL: Variable fill consisting well -graded gravel and areas of clayey gravel were encountered at the site from the ground surface to approximately 1 to 2 feet bgs. LEAN CLAY (CL): Lean clay with sand to sandy lean clay was encountered under the overlying fill to depths of approximately 4.5 to 5.5 feet bgs. The clay was generally stiff to hard with unconfined compressive strengths between 1.0 to 4.5 tsf, brown, moist, exhibited low to medium plasticity, and contained fine- to medium -grained sand. SANDY SILT (ML): Sandy silt was encountered at the site in test pits TP -3 and TP -6 at depths of 3.5 to 5 bgs and 3 to 5.5 feet bgs, respectively. The material was hard with unconfined compressive strengths of 4.5 tsf, light brown, moist, exhibited low plasticity, and contained fine- to medium -grained sand. WELL -GRADED Well -graded gravel was encountered in all test pits below the fine-grained material at GRAVEL with SILT approximately 6 feet bgs to the termination depth. The material was generally gray to (GW -GM): brown, moist to wet, contained fine to coarse rounded gravels, fine- to coarse-grained sand, and varying amounts of silt. A 3 -foot -thick zone of silty sand with gravel was encountered within the gravel layer in TP -4 at a depth of 6.5 feet. 03 P V Y September 22, 2020 3 PBS Project 13415002 Ceotechnical Engineering Report Ridgeview Gardens Ridgeview Gardens, LLC Springfield, Oregon 2.4 Groundwater Static groundwater was encountered during our explorations at approximately 11 feet bgs in several test pits. Based on a review of regional groundwater elevation mapping of the Eugene -Springfield area, the approximate groundwater elevation is 480 to 490 feet amsl (USGS, 1973). This groundwater elevation, and the surface elevation of the site, are consistent with the groundwater levels encountered during our exploration. Please note that groundwater levels can fluctuate during the year depending on climate, irrigation season, extended periods of precipitation, drought, and other factors. 2.5 Infiltration Testing PBS completed two open -hole, falling -head infiltration tests in test pits TP -2 and TP -7 at a depth of 5.5 and 6.0 feet bgs, respectively. The infiltration testing was conducted within the bottom of the test pit exploration. The test pit was filled with water to achieve an approximately 1 -foot -high water head. After a period of saturation, the height of the water level in the test pit was then measured initially and at regular, timed intervals. Results of our field infiltration testing are presented in Table 1. Table 1. Infiltration Test Results * based on field infiltration rate The infiltration rates listed in Table 1 are not permeabilities/hydraulic conductivities, but field -measured rates, and do not include correction factors related to long-term infiltration rates. The design engineer should determine the appropriate correction factors to account for the planned level of pre-treatment, maintenance, vegetation, siltation, etc. Field -measured infiltration rates are typically reduced by a minimum factor of 2 to 4 for use in design. Soil types can vary significantly over relatively short distances. The infiltration rates noted above are representative of one discrete location and depth. Installation of infiltration systems within the layer the field rate was measured is considered critical to proper performance of the systems. At the time of this report, the locations of proposed stormwater facilities were not certain. Once the facility locations are finalized, additional infiltration testing should be completed at these locations and depths. The United States Department of Agriculture (USDA) categorizes soils in four hydrologic soil groups, A through D, and are designated mainly by particle size and hydraulic conductivity. Table 3 below shows general characteristics of each group as they are identified by the USDA. Table 2. USDA Hydrologic Soil Group Parameters Soil Properties Hydrologic) Soil Group _ Saturated Hydraulic Conductivity (k) <>5.67 1.42<k<5.67 I 0.14<k<1.42 I k<0.14 PBS September 22, 2020 4 PBS Proiec[ 73415,002 Field Measured Recommended Test Location Depth (feet bgs) Infiltration Rate Soil Classification Hydrologic Soil (in/hr) Grou Well -graded TP -2 5.5 4.5 B GRAVEL GW) Well -graded GRAVEL TP -7 6.0 21 B with silt (GW -GM) * based on field infiltration rate The infiltration rates listed in Table 1 are not permeabilities/hydraulic conductivities, but field -measured rates, and do not include correction factors related to long-term infiltration rates. The design engineer should determine the appropriate correction factors to account for the planned level of pre-treatment, maintenance, vegetation, siltation, etc. Field -measured infiltration rates are typically reduced by a minimum factor of 2 to 4 for use in design. Soil types can vary significantly over relatively short distances. The infiltration rates noted above are representative of one discrete location and depth. Installation of infiltration systems within the layer the field rate was measured is considered critical to proper performance of the systems. At the time of this report, the locations of proposed stormwater facilities were not certain. Once the facility locations are finalized, additional infiltration testing should be completed at these locations and depths. The United States Department of Agriculture (USDA) categorizes soils in four hydrologic soil groups, A through D, and are designated mainly by particle size and hydraulic conductivity. Table 3 below shows general characteristics of each group as they are identified by the USDA. Table 2. USDA Hydrologic Soil Group Parameters Soil Properties Hydrologic) Soil Group _ Saturated Hydraulic Conductivity (k) <>5.67 1.42<k<5.67 I 0.14<k<1.42 I k<0.14 PBS September 22, 2020 4 PBS Proiec[ 73415,002 Geotechnical Engineering Report Ridgeview Gardens Ridgeview Gardens, LLC Springfield, Oregon 3 CONCLUSIONS AND RECOMMENDATIONS 3.1 Geotechnical Design Considerations The subsurface conditions at the site consist of a generally thin, continuous layer of undocumented fill, underlain by fine-grained clay overlying gravel. Based on our observations and analyses, conventional foundation support on shallow spread footings is feasible for the proposed new building bearing on undisturbed native material; however, footings should not be supported on undocumented fill. Excavation with conventional equipment is feasible at the site. Depending on design elevation of proposed stormwater facilities at the site, groundwater elevations observed at the time of our explorations may control the final design elevation. Infiltration rates within fine-grained materials at the site will likely be significantly lower than the gravel in which infiltration testing was performed. 3.2 Shallow Foundations Shallow spread footings bearing on native fine-grained soils may be used to support loads associated with the new structures, provided the recommendations in this report are followed. Footings should not be supported on undocumented fill. 3.2.1 Minimum Footing Widths and Design Bearing Pressure Continuous wall and isolated spread footings should be at least 18 and 24 inches wide, respectively. Footings should be sized using a maximum allowable bearing pressure of 2,500 pounds per square foot (psf). This is a net bearing pressure and the weight of the footing and overlying backfill can be disregarded in calculating footing sizes. The recommended allowable bearing pressure applies to the total of dead plus long-term live loads. Allowable bearing pressures may be increased by one-third for seismic and wind loads. Footings will settle in response to column and wall loads. Based on our evaluation of the subsurface conditions and our analysis, we estimate post -construction settlement will be less than 1 inch for the column and perimeter foundation loads. Differential settlement will be on the order of one-half of the total settlement. 3.2.2 Footing Embedment Depths PBS recommends that all footings be founded a minimum of 18 inches below the lowest adjacent grade. The footings should be founded below an imaginary line projecting upward at a 1 HAV (horizontal to vertical) slope from the base of any adjacent, parallel utility trenches or deeper excavations. 3.2.3 Footing Preparation Excavations for footings should be carefully prepared to a neat and undisturbed state. A representative from PBS should confirm suitable bearing conditions and evaluate all exposed footing subgrades. Observations should also confirm that loose or soft materials have been removed from new footing excavations and concrete slab -on -grade areas. Localized deepening of footing excavations may be required to penetrate loose, wet, or deleterious materials. PBS recommends a layer of compacted, crushed rock be placed over the footing subgrades to help protect them from disturbance due to foot traffic and the elements. Placement of this rock is the prerogative of the contractor, regardless, the footing subgrade should be in a dense or stiff condition prior to pouring concrete. Based on our experience, approximately 4 inches of compacted crushed rock will be suitable beneath the footings. 3.2.4 Lateral Resistance Lateral loads can be resisted by passive earth pressure on the sides of footings and grade beams, and by friction at the base of the footings. A passive earth pressure of 250 pounds per cubic foot (pcf) may be used for ON PBS 5 PBSeptember22,2020 S Project -73415.002 Geotechnical Engineering Report Ridgeview Gardens Ridgeview Gardens, LLC Springfield, Oreton footings confined by native soils and new structural fills. The allowable passive pressure has been reduced by a factor of two to account for the large amount of deformation required to mobilize full passive resistance. Adjacent floor slabs, pavements, or the upper 12 -inch depth of adjacent unpaved areas should not be considered when calculating passive resistance. For footings supported on native soils or new structural fills, use a coefficient of friction equal to 0.35 when calculating resistance to sliding. These values do not include a factor of safety (FS). 3.3 Floor Slabs Satisfactory subgrade support for building floor slabs can be obtained from the native silty sand to sandy silt or gravel fill subgrade prepared in accordance with our recommendations presented in the Site Preparation, Wet/Freezing Weather and Wet Soil Conditions, and Select Granular Fill sections of this report. A minimum 6 - inch -thick layer of imported granular material should be placed and compacted over the prepared subgrade. Thicker aggregate sections may be necessary where undocumented fill is present, soft/loose soils are present at subgrade elevation, and/or during wet conditions. Imported granular material should be composed of crushed rock or crushed gravel that is relatively well graded between coarse and fine, contains no deleterious materials, has a maximum particle size of 1 inch, and has less than 5 percent by dry weight passing the US Standard No. 200 Sieve. Floor slabs supported on a subgrade and base course prepared in accordance with the preceding recommendations may be designed using a modulus of subgrade reaction (k) of 150 pounds per cubic inch (Pci). 3.4 Seismic Design Considerations 3.4.1 Code -Based Seismic Design Parameters The current seismic design criteria for this project are based on the 2019 Oregon Structural Specialty Code (OSSC). Based on subsurface conditions encountered during our exploration, Site Class D is appropriate for use in design. The seismic design criteria, in accordance with the 2019 OSSC, are summarized in Table 3. Table 3. 2019 OSSC Seismic Design Parameters Parameter Short Period 1 Second Maximum Credible Earthquake Spectral Acceleration S, = 0.64 g Si = 0.37 g Site Class D Site Coefficient Fa = 1.29 F„ = 1.93* Adjusted Spectral Acceleration Sms = 0.83 g SMI = ** Design Spectral Response Acceleration Parameters SDs = 0.55 g SDI = ** MceG Peak Ground Acceleration PGA = 0.30 g Site Amplification Factor at PGA FPGA = 1.3 Site Modified Peak Ground Acceleration PGAM = 0.39 g g=Acceleration due to gravity ' This value of F, shall only be used to calculate T, •" Site-specific site response analysis is not required for structures on Site Class 0 sites with Si greater than or equal to 0.2, provided the value of the seismic response coefficient C, is determined by Eq. (12.8-2) for values of T s 1.5T. and taken as equal to 1.5 times the value computed in accordance with either Eq. (128-3) for TL >> T > 1.ST, or Eq. (12,84) for T > TL. PBS 6 PBS 22, 2020 J S Proierd 73415002 Geotechnical Engineering Report Ridgeview Gardens Ridgeview Gardens, LLC Springfield, Oregon 3.4.2 Liquefaction Potential Liquefaction is defined as a decrease in the shear resistance of loose, saturated, cohesionless soil (e.g., sand) or low plasticity silt soils, due to the buildup of excess pore pressures generated during an earthquake. This results in a temporary transformation of the soil deposit into a viscous fluid. Liquefaction can result in ground settlement, foundation bearing capacity failure, and lateral spreading of ground. Based on a review of the Oregon Statewide Geohazard Viewer (HazVu), the site is not located in a liquefaction hazard area. Based on the soil types and relative density/consistency of site soils encountered in our explorations, our current opinion is that the risk of structurally damaging liquefaction settlement at the site is low. 3.5 Ground Moisture 3.5.1 General The perimeter ground surface and hard-scape should be sloped to drain away from all structures and away from adjacent slopes. Gutters should be tight -lined to a suitable discharge and maintained as free-flowing. All crawl spaces should be adequately ventilated and sloped to drain to a suitable, exterior discharge. 3.5.2 Perimeter Footing Drains Due to the relatively low permeability of surficial site soils and the potential for perched groundwater at the site, we recommend perimeter foundation drains be installed around all proposed structures. The foundation subdrainage system should include a minimum 4 -inch diameter perforated pipe in a drain rock envelope. A non -woven geotextile filter fabric, such as Miraf 140N or equivalent, should be used to completely wrap the drain rock envelope, separating it from the native soil and footing backfill materials. The invert of the perimeter drain lines should be placed approximately at the bottom of footing elevation. Also, the subdrainage system should be sealed at the ground surface. The perforated subdrainage pipe should be laid to drain by gravity into a non -perforated solid pipe and finally connected to the site drainage stem at a suitable location. Water from downspouts and surface water should be independently collected and routed to a storm sewer or other positive outlet. This water must not be allowed to enter the bearing soils. 3.5.3 Vapor Flow Retarder A continuous, impervious barrier must be installed over the ground surface in the crawl space and under slabs of all structures. Barriers should be installed per the manufacturer's recommendations. 3.6 Pavement Design The provided pavement recommendations were developed based on our experience with similar developments and references the associated Oregon Department of Transportation (ODOT) specifications for construction. The minimum recommended pavement section thicknesses are provided in Table 4. Depending on weather conditions at the time of construction, a thicker aggregate base course section could be required to support construction traffic during preparation and placement of the pavement section. Table 4. Minimum AC Pavement Sections Traffic Loading AC (inches) Base Course (inches) Subgrade Pull -in Car Parking Only 2.5 6 Stiff subgrade as verified by PBS personnel* ON PBS ] PBS 22, 020 S Projec[]3415.002 Geotechnical Engineering Report Ridgeview Gardens Ridgeview Gardens, LLC Springfield, Oregon Traffic Loading AC (inches) Base Course (inches) I Subgrade Drive Lanes and AccessStiff 3 subgrade as verified by Roads 9 PBS personnel* Subgrade must pass proofroll The asphalt cement binder should be selected following ODOT SS 00744.11 —Asphalt Cement and Additives. The AC should consist of ',,-inch hot mix asphalt concrete (HMAC) with a maximum lift thickness of 3 inches. The AC should conform to ODOT SS 00744.13 and 00744.14 and be compacted to 91 percent of the maximum theoretical density (Rice value) of the mix, as determined in accordance with ASTM D2041. Heavy construction traffic on new pavements or partial pavement sections (such as base course over the prepared subgrade) will likely exceed the design loads and could potentially damage or shorten the pavement life; therefore, we recommend construction traffic not be allowed on new pavements, or that the contractor take appropriate precautions to protect the subgrade and pavement during construction. If construction traffic is to be allowed on newly constructed road sections, an allowance for this additional traffic will need to be made in the design pavement section. 4 CONSTRUCTION RECOMMENDATIONS 4.1 Site Preparation Construction of the proposed structure will involve clearing and grubbing of the existing vegetation or demolition of possible existing structures. Demolition should include removal of existing pavement, utilities, etc., throughout the proposed new development. Underground utility lines or other abandoned structural elements should also be removed. The voids resulting from removal of foundations or loose soil in utility lines should be backfilled with compacted structural fill. The base of these excavations should be excavated to firm native subgrade before filling, with sides sloped at a minimum of 1 HAV to allow for uniform compaction. Materials generated during demolition should be transported off site or stockpiled in areas designated by the owner's representative. 4.1.1 Proofrolling/Subgrade Verification Following site preparation and prior to placing aggregate base over shallow foundation, floor slab, and pavement subgrades, the exposed subgrade should be evaluated either by proofrolling or another method of subgrade verification. The subgrade should be proofrolled with a fully loaded dump truck or similar heavy, rubber -tire construction equipment to identify unsuitable areas. If evaluation of the subgrades occurs during wet conditions, or if proofrolling the subgrades will result in disturbance, they should be evaluated by PBS using a steel foundation probe. We recommend that PBS be retained to observe the proofrolling and perform the subgrade verifications. Unsuitable areas identified during the field evaluation should be compacted to a firm condition or be excavated and replaced with structural fill. 4.1.2 Wet/Freezing Weather and Wet Soil Conditions Due to the presence of fine-grained clay and sands in the near -surface materials at the site, construction equipment may have difficulty operating on the near -surface soils when the moisture content of the surface soil is more than a few percentage points above the optimum moisture required for compaction. Soils disturbed during site preparation activities, or unsuitable areas identified during proofrolling or probing, should be removed and replaced with compacted structural fill. Site earthwork and subgrade preparation should not be completed during freezing conditions, except for mass excavation to the subgrade design elevations. ON PBS September 22, 2020 B PBS Protect ]x615 002 Geotechnical Engineenng Report Ridgeview Gardens Ridgeview Gardens, LLC Springfield, Oregon Protection of the subgrade is the responsibility of the contractor. Construction of granular haul roads to the project site entrance may help reduce further damage to the pavement and disturbance of site soils. The actual thickness of haul roads and staging areas should be based on the contractors' approach to site development, and the amount and type of construction traffic. The imported granular material should be placed in one lift over the prepared undisturbed subgrade and compacted using a smooth -drum, non -vibratory roller. A geotextile fabric should be used to separate the subgrade from the imported granular material in areas of repeated construction traffic. The geotextile should meet the specifications of COOT SS Section 02320.10 and SS 02320.20, Table 02320-1 for soil separation. The geotextile should be installed in conformance with COOT SS Section 00350 — Geosynthetic Installation. 4.1.3 Dry Weather Conditions Clay soils should be covered within 4 hours of exposure by a minimum of 4 inches of crushed rock or plastic sheeting during the dry season. Exposure of these materials should be coordinated with the geotechnical engineer so that the subgrade suitability can be evaluated prior to being covered. 4.1.4 Compacting Test Pit Locations The test pit excavations were backfilled using the excavator bucket and relatively minimal compactive effort; therefore, soft spots can be expected at these locations. We recommend that the relatively uncompacted soil be removed from the test pits to a depth of at least 3 feet below finished subgrade elevation in pavement areas and to full depth in building areas. The resulting excavation should be backfilled with structural fill. 4.2 Excavation The near -surface soils at the site can be excavated with conventional earthwork equipment. Sloughing and caving should be anticipated. All excavations should be made in accordance with applicable Occupational Safety and Health Administration (OSHA) and state regulations. The contractor is solely responsible for adherence to the OSHA requirements. Trench cuts should stand relatively vertical to a depth of approximately 4 feet bgs, provided no groundwater seepage is present in the trench walls. Open excavation techniques may be used provided the excavation is configured in accordance with the OSHA requirements, groundwater seepage is not present, and with the understanding that some sloughing may occur. Trenches/excavations should be flattened if sloughing occurs or seepage is present. Use of a trench shield or other approved temporary shoring is recommended if vertical walls are desired for cuts deeper than 4 feet bgs. If dewatering is used, we recommend that the type and design of the dewatering system be the responsibility of the contractor, who is in the best position to choose systems that fit the overall plan of operation. 4.3 Structural Fill The extent of site grading is currently unknown; however, PBS estimates that cuts and fills may be on the order of up to 2 feet. Structural fill should be placed over subgrade that has been prepared in conformance with the Site Preparation and Wet/Freezing Weather and Wet Soil Conditions sections of this report. Structural fill material should consist of relatively well -graded soil, or an approved rock product that is free of organic material and debris, and contains particles not greater than 4 inches nominal dimension. The suitability of soil for use as compacted structural fill will depend on the gradation and moisture content of the soil when it is placed. As the amount of fines (material finer than the US Standard No. 200 Sieve) increases, soil becomes increasingly sensitive to small changes in moisture content and compaction becomes more difficult to achieve. Soils containing more than about 5 percent fines cannot consistently be compacted to a dense, non -yielding condition when the water content is significantly greater (or significantly less) than optimum. OR PBS September 22, 2020 PBS Project 73415.002 Geotechnical Engineering Report Ridgevjew Gardens Ridgevjew Gardens, LLC Springfield, Oregon If fill and excavated material will be placed on slopes steeper than 5H:1 V, these must be keyed/benched into the existing slopes and installed in horizontal lifts. Vertical steps between benches should be approximately 2 feet. 4.3.1 On -Site Soil On-site soils encountered in our explorations are generally suitable for placement as structural fill during moderate, dry weather when moisture content can be maintained by air drying and/or addition of water. Due to the moderate plasticity of the clay soils at the site, even during dry conditions, regular, frequent aerating of soils will be required to reach the optimum moisture for compaction. Due to the time required to moisture condition site soils and the seasonal limitations, reuse of on-site soils may not be economically feasible. The fine-grained fraction of the site soils are moisture sensitive, and during wet weather, these soils may become unworkable because of excess moisture content. If used, the material should be placed in lifts with a maximum uncompacted thickness of approximately 8 inches and compacted to at least 92 percent of the maximum dry density, as determined by ASTM D1557 (modified proctor). 4.3.2 Borrow Material Borrow material for general structural fill construction should meet the requirements set forth in ODOT SS 00330.12 — Borrow Material. When used as structural fill, borrow material should be placed in lifts with a maximum uncompacted thickness of approximately 8 inches and compacted to not less than 92 percent of the maximum dry density, as determined by ASTM D1 S57. 4.3.3 Select Granular Fill Selected granular backfill used during periods of wet weather for structural fill construction should meet the specifications provided in ODOT SS 00330.14— Selected Granular Backfill. The imported granular material should be uniformly moisture conditioned to within about 2 percent of the optimum moisture content and compacted in relatively thin lifts using suitable mechanical compaction equipment. Selected granular backfill should be placed in lifts with a maximum uncompacted thickness of 8 to 12 inches and be compacted to not less than 95 percent of the maximum dry density, as determined by ASTM D1557, 4.3.4 Crushed Aggregate Base Crushed aggregate base course below floor slabs, spread footings, and asphalt concrete pavements should be clean crushed rock or crushed gravel that contains no deleterious materials and meets the specifications provided in ODOT SS 02630.10 — Dense -Graded Aggregate, and has less than 5 percent by dry weight passing the US Standard No. 200 Sieve. The crushed aggregate base course should be placed in lifts with a maximum uncompacted thickness of 8 to 12 inches and be compacted to at least 95 percent of the maximum dry density as determined by ASTM D1557. 4.3.5 Utility Trench Backfill Pipe bedding placed to uniformly support the barrel of pipe should meet specifications provided in ODOT SS 00405.12 — Bedding. The pipe zone that extends from the top of the bedding to at least 8 inches above utility lines should consist of material prescribed by ODOT SS 00405.13 — Pipe Zone Material. The pipe zone material should be compacted to at least 90 percent of the maximum dry density, as determined by ASTM D1557, or as required by the pipe manufacturer. Under pavements, paths, slabs, or beneath building pads, the remainder of the trench backfill should consist of well -graded granular material with less than 10 percent by dry weight passing the US Standard No. 200 Sieve, ON PB5 2020 0 10 PBS Project ]3415002 Geotechnical Engineering Report Ridgeview Gardens Ridgeview Gardens, LLC Springfield, Oregon and should meet standards prescribed by COOT SS 00405.14—Trench Backfill, Class B or D. This material should be compacted to at least 92 percent of the maximum dry density, as determined by ASTM D1557 or as required by the pipe manufacturer. The upper 2 feet of the trench backfill should be compacted to at least 95 percent of the maximum dry density, as determined by ASTM D1557. Controlled low -strength material (CLSM), ODOT SS 00405.14—Trench Backfill, Class E, can be used as an alternative. Outside of structural improvement areas (e.g., pavements, sidewalks, or building pads), trench material placed above the pipe zone may consist of general structural fill materials that are free of organics and meet ODOT SS 00405.14 —Trench Backfill, Class A. This general trench backfill should be compacted to at least 90 percent of the maximum dry density, as determined by ASTM D1557, or as required by the pipe manufacturer or local jurisdictions. 4.3.6 Stabiliution Material Stabilization rock should consist of pit or quarry run rock that is well -graded, angular, crushed rock consisting of 4- or 6 -inch -minus material with less than 5 percent passing the US Standard No.4 Sieve. The material should be free of organic matter and other deleterious material. ODOT SS 00330.16 — Stone Embankment Material can be used as a general specification for this material with the stipulation of limiting the maximum size to 6 inches. 5 ADDITIONAL SERVICES AND CONSTRUCTION OBSERVATIONS In most cases, other services beyond completion of a final geotechnical engineering report are necessary or desirable to complete the project. Occasionally, conditions or circumstances arise that require additional work that was not anticipated when the geotechnical report was written. PBS offers a range of environmental, geological, geotechnical, and construction services to suit the varying needs of our clients. PBS should be retained to review the plans and specifications for this project before they are finalized. Such a review allows us to verify that our recommendations and concerns have been adequately addressed in the design. Satisfactory earthwork performance depends on the quality of construction. Sufficient observation of the contractor's activities is a key part of determining that the work is completed in accordance with the construction drawings and specifications. We recommend that PBS be retained to observe general excavation, stripping, fill placement, footing subgrades, and/or pile installation. Subsurface conditions observed during construction should be compared with those encountered during the subsurface explorations. Recognition of changed conditions requires experience; therefore, qualified personnel should visit the site with sufficient frequency to detect whether subsurface conditions change significantly from those anticipated. 6 LIMITATIONS This report has been prepared for the exclusive use of the addressee, and their architects and engineers, for aiding in the design and construction of the proposed development and is not to be relied upon by other parties. It is not to be photographed, photocopied, or similarly reproduced, in total or in part, without express written consent of the client and PBS. It is the addressee's responsibility to provide this report to the appropriate design professionals, building officials, and contractors to ensure correct implementation of the recommendations. The opinions, comments, and conclusions presented in this report are based upon information derived from our literature review, field explorations, laboratory testing, and engineering analyses. It is possible that soil, rock, or groundwater conditions could vary between or beyond the points explored. If soil, rock, or ON PBS September ,020 i t PBS Project A4141 5.002 Geotechnical Engineering Report Ridgeview Gardens Ridgeview Gardens, LLC Springfield. Oregon groundwater conditions are encountered during construction that differ from those described herein, the client is responsible for ensuring that PBS is notified immediately so that we may reevaluate the recommendations of this report. Unanticipated fill, soil and rock conditions, and seasonal soil moisture and groundwater variations are commonly encountered and cannot be fully determined by merely taking soil samples or completing explorations such as test pits. Such variations may result in changes to our recommendations and may require additional funds for expenses to attain a properly constructed project; therefore, we recommend a contingency fund to accommodate such potential extra costs. The scope of work for this subsurface exploration and geotechnical report did not include environmental assessments or evaluations regarding the presence or absence of wetlands or hazardous substances in the soil, surface water, or groundwater at this site. If there is a substantial lapse of time between the submission of this report and the start of work at the site, if conditions have changed due to natural causes or construction operations at or adjacent to the site, or if the basic project scheme is significantly modified from that assumed, this report should be reviewed to determine the applicability of the conclusions and recommendations presented herein. Land use, site conditions (both on and off site), or other factors may change over time and could materially affect our findings; therefore, this report should not be relied upon after three years from its issue, or in the event that the site conditions change. ON PB` September 22, 2020 of 12 P65 Protect 73415.002 Geotechnical Engineering Report Ridgeview Gardens Ridgeview Gardens, LLC Springfield, Oregon 7 REFERENCES ASCE. (2016). Minimum Design Loads for Buildings and Other Structures (ASCE 7-16). Brocher, T. M., Wells, R. E., Lamb, A. P., and Weaver, C. S. (2017). Evidence for distributed clockwise rotation of the crust in the northwestern United States from fault geometries and focal mechanisms. Tectonics, Vol. 36, No.5, pp. 787-818. DOGAMI. (2020a). [Interactive Map]. DOGAMI Lidar Viewer. Oregon Department of Geology and Mineral Industries, Oregon Lidar Consortium. https:Hgis.dogami.oregon.gov/maps/lidawiewer/. Accessed September 2020. DOGAMI. (2020). [Interactive Map]. Oregon Hai Statewide Geohazards Viewer. Oregon Department of Geology and Mineral Industries, Earthquake Liquefaction. https://gis.dogami.oregon.gov/maps/hazvu/. Accessed September 2020. McClaughry, ). D., Wiley, T. 1., Ferns, M. L., and Madin, I. P. (2010). Digital geologic map of the southern Willamette Valley, Benton, Lane, Linn, Marion, and Polk Counties, Oregon. DOGAMI Open -File Report 0- 10-03. ODOT SS. (2018). Oregon Standard Specifications for Construction. Salem, Oregon. Oregon Department of Transportation. OSSC. (2019). Oregon Structural Specialty Code (OSSC). Based on IBC. (2018 International Building Code). Country Club Hills, IL International Code Council, Inc. US Geological Survey (2020). Quaternary fault and fold database for the United States, accessed September 2020 from USGS website: https://earthquake.usgs.gov/hazards/gfau Its/. US Geological Survey (1973). Ground Water in the Eugene -Springfield Area, Southern Willamette Valley, Oregon. United States Geological Survey. Geological Survey Water -Supply Paper No. 2018. Wiley, T.1. (2006). Preliminary Geologic Map of the Albany Quadrangle, Linn, Marion, and Benton Counties, Oregon, Oregon Department of Geology and Mineral Industries (DOGAMI), open -file report 0-06-26. Yeats, R. S., Graven, E. P., Werner, K. S., Goldfinger, Chris, and Popowski, T. A. (1996). Tectonics of the Willamette Valley, Oregon, in Rogers, A. M., Walsh, T. 1., Kockelman, W. 1., and Priest, G. R., ads., Assessing earthquake hazards and reducing risk in the Pacific Northwest: US Geological Survey Professional Paper 1650, v. 1, p. 183-222. ON PBS Septembe 341 ,020 13 PBS Project 73415.002 Geotechnical -Engineering Report The Geoprofessional Business Association (GBA) has prepared this advisory to help you — assumedly a client representative — interpret and apply this geotechnical -engineering report as effectively as possible. In that way, you can benefit from a lowered exposure to problems associated with subsurface conditions at project sites and development of them that, for decades, have been a principal cause of construction delays, cost overruns, claims, and disputes. If you have questions or want more information about any of the issues discussed herein, contact your GBA-member geotechnical engineer. Active engagement in GBA exposes geotechnical engineers to a wide array of risk -confrontation techniques that can be of genuine benefit for everyone involved with a construction project. Understand the Geotechnical -Engineering Services Provided for this Report Geotechnical-engincering services typically include the planning, collection, interpretation, and analysis ofexploratory data from widely spaced borings and/or test pits. Field data are combined with results from laboratory tests of out and rode samples obtained from field exploration (if applicable), observations made during site reconnaissance, and historical information to form one or more models of the expected subsurface conditions beneath the site. Local geology and alterations of the site surface and subsurface by previous and proposed construction are also important considerations. Gemechnical engineers apply their engineering training, experience, and judgment to adapt the requirements of the prospective project to the subsurface model(s). Estimates are made of the subsurface conditions that will lily be exposed during construction as well as the expected performance of foundations and other structures being planned and/or affected by construction activities. The columnation of these geouchnical engineering services is typically a geotechnical -engine ring repertpmviding the data obtained, a discussion of the submvface model(s), the engineering and geologic engineering assessments and analyses made, and the recommendations developed to satisfy the given requirements ofthe project. These reports may be titled investigations, explorations, studies, assessments, or evaluations. Regardless of the title used, the geotechmeareagirioning report is an engineering interpretation of the subsurface conditions within the context ofthe project and does not represent a dose examination, systematic inquiry, or thorough investigation of all site and subsurface conditions. Geotechnical -Engineering Services are Performed for Specific Purposes, Persons, and Projects, and At Specific Times Geotechnical engineers structure their services to meet the specific needs, goals, and risk management preferences of their clients. A geotechnical -engineering study conducted for a given civil ammeter will not likely meet the needs of a civil -works constructor or even a different civil engineer. Because each geotechnical -engineering study, is unique, each geotechnical -engineering report is unique, prepared solely for the client. Likewise, geotechnical-angineering services are performed for a specific project and purpose. For example, it is unlikely that a geotechnical - engineering study for a refrigerated warehouse will be the same as ne prepared for a parking garage; and a few borings drilled during a preliminary study to evaluate site feasibility will not be adequate to develop geotechnical design recommendations for the project. Do not rely on this report if your geotechnical engineer prepared it: • for a different client; for a different project or purpose; • for a different site (that may or may not include all or a portion of the orighral site); or before important events occurred at the.site or adjacent to it; e.g., man-made events like construction or environmental remediation, or natural events like floods, droughts, earthquakes, or groundwater Fluctuations. Note, we, the reliability of a gemechnical-engineering repair can be affected by the passage oftime, because of factors like changed subsurface conditions; new or modified codes, standards, or regulations; or new techniques or tools. Ifyou are the least bit uncertain about the continued reliability of this report, contact your geotechnical engineer before applying the recommendations in it A minor amount of additional testing or analysis after the passage of time - If any is required at all- could prevent major problems. Read this Report in Full Costly problems have occurred because those relying on a geotechnical - engineering report did not read the report in its entirety. Do not rely on an executive summary. Do not read selective elements only. Read and refer to the report in full. You Need to Inform Your Geotechnical Engineer About Change Your geotechnical engineer considered unique, project -specific factors when developing the scope of study behind this report and developing the confirmation -dependent recommendations the report conveys. Typical changes that could erode the reliability of this report include those that affect. • the sites size or shape; • the elevation, configuration, location, orientation, function or weight of the proposed structure and the desired performance cnilaria; the composition of the design team; or • project ownership. As a general rule, always inform your geotermical engineer ofproject or site changes - even minor ones - and request an assessment of their impact. The geotechnical eegre,er he prepared this report cannot acrept responsibility m liability forproble. that artre because the geotechnical engineer was not informed about deve(opmen s the engineer otherwise would have considered. Most of the "Findings" Related in This Report Are Professional Opinions Before construction begins,geotechnical engineers explore a sites subsurface using various sampling and testing procedures. Geotechnical engineers can observe actual subsurface mndider, only at thane spec[frc lommeas where sampling and testing is performed. Tan data derived from that sampling and testing were wed by your geotechnical engineer, who then applied professional judgement to form opinions about subsurface conditions throughout the site. Actual sitewide-subsurface conditions may differ - maybe significantly - from those indicated in this report. Confront that risk by retaining your geotechnical engineer to secve on the design team through project completion to obtain informed guidance quickly, whenever needed. This Report's Recommendations Are Confirmation -Dependent The recommendations included in this report- including airy options or alternatives - are coNirmation-dependent In other words, they are not final, because the geotechnical engineer who developed them relied heavily on judgement and opinion to do so, Your geotechrdcal engineer can finalize the recommendations only after observing actual subsurface condelorrs exposed during construction. If through observation your grot -hnical engineer confirms that the conditions assmrud to exist actually do exist, the recommendations can be relied upon, assuming no other changes have occurred. Tlsegeotechnical engine who prepared this report cannot asswne responsibility mliabilityfor confirmafion-dependent recommendatlons if you fail to retain that engineer be perform conshuction vowry itis, This Report Could Be Misinterpreted Other design professionals misinterpretation of geotechnical - engineering reports has resulted in costly problems. Confront that risk by having your geotechnical engineer serve as a continuing member of the design team, to: confer with other design -team members; help develop specifications; • review pertinent elements of other design professionals plans and specifications; and • beavailablewhenevergeotechnical-engineeringguida me needed You should also confront die risk of constructors misinterpreting this report. Do so by retaining your geotechnical engineer to participate in prebid and preconstruction conferences and to perform construction - phase observations. Give Constructors a Complete Report and Guidance Some owners and design professionals mistakenly believe they can shift unanticipated -subsurface -conditions liability to constructors by limiting the information they provide for bid preparation. To help prevent the costly, contentions problems this practice has caused, include the complete geotechnical -engineering report, along with any attachments or appendices, with your contract documents, but be certain to note conspicuously that you've included the material for information purposes only, 'to avoid misunderstanding, you may also want to note that "informational purposes" means constructors have no right to rely on the interpretations, opinions, conclusions, or recommendations in the report Be certain that constructors know they may learn about specific project requirements, including options selected from the report, only from the design drawings and specifications. ground constructors that they may perform their own studies if they want m, and be sure to allow enough time to permit them to do so. Only then might you be in a position to give constructors the information available to you, while requiring them to at least share some of the financial responsibilities stemming from unanticipated conditions. Conducting prebid and preconstmction confrenms can also be valuable in this respect. Read Responsibility Provisions Closely Some client representatives, design professionals, and constructors do not realize that geotechnical engineering is far less exact than other engineering disciplines. This happens in part because soil and rock on project sites are typically heterogeneous and not manufactured materials with well-defined engineering properties like steel and concrete. That lack of understanding has nurtured unrealistic expectations that have resulted in disappointments, delays, cost overruns, claims, and disputes. '1'o confront that risk, geotechnical engineers commonly include explanatory pro in their reports. Sometimes labeled "limitations," any of these provisions indicate where geotechnical engine re responsibilities begin and end, to help others recognize their own responsibilities and risks. Read these provisions closely. Ask questions. Your geotechnical engineer should respond fully and frankly. Geoenvironmental Concerns Are Not Covered The personnel, equipment, and techniques used to perform an mtalstudy -e.g.,a'phasron'or'phose-nvd'envimnmental site assessment - differ significantly fmm those used to pest.. a gmtechnical-engineering study. For that reason, a geotechnical -engineering report does not usually provide environmental findings, conclusions, or recommendations; e. g., about the likelihood of encountering underground storage tanks or roosted contaminants. Unanliczpaled subsurface earchomminal problems have led to project failures. If you have not obtained your own emmwgmtal information about the project site, ask your geotechnind consultant for a recommendation on how to find environmental risk -management guidance. Obtain Professional Assistance to Deal with Moisture Infiltration and Mold While your geotechnical engineer may have addressed groundwater, water infiltration, or similar issues in this report, the engineer's services were not designed, conducted, or intended to prevent migration of moisture - including water vapor - from the soil through building slabs and walls and into the building interior, where it can cause mold growth and material performance deficiencies. Accordingly, proper implementation of the geotechnical engineer recommendations will not of ihelfbe sufficient to prevent inobfnre tnfdtration. Confront the risk of moisture tnfiltration by cluding building -envelope or mold specialists on the design team. Geotechnical engineers are not building -envelope or mold specialists. GEOPROFESSIONAL BUSINESS / - ASSOCIATION Telephone: 301/565-2733 e-mail: info@geoprofessional.org nnsvegeoprofessional.org Boures Jua-unes((ural. al, xuh the expos wdrien pxmission of to or n, an elemem urn myen of at, sod. so uses this d ommenr without be, a Figures a�S ti 8 P — batten nve hn s Vnw ewm pblk wp mp It F Jhmr '+�eh P a _s i n' u +eQ gar oa Aom S Z vi nn.,. ar m gb iam 4 L a 1 inch = 4,000 feet wN"+ F@et 0 ,2,000 4,000000 VICINITY MAP RIDGEVIEW GARDENS 5050 MAIN STREET SPRINGFIELD, OREGON DATE: SEP 2020 - PROJECT: 73415.002 PBS FIGURE C 5 Y +P N4(aNT PIS6AX +eQ gar oa Aom S Z vi nn.,. ar m gb iam 4 L a 1 inch = 4,000 feet wN"+ F@et 0 ,2,000 4,000000 VICINITY MAP RIDGEVIEW GARDENS 5050 MAIN STREET SPRINGFIELD, OREGON DATE: SEP 2020 - PROJECT: 73415.002 PBS FIGURE Appendix A Field Explorations Geotechnical Engineering Report Ridgeview Gardens, LLC Appendix A: Field Explorations Ridgeview Gardens Springfield, Oregon Al GENERAL PBS explored subsurface conditions at the project site by excavating test pits to depths of up to 12 feet bgs on September 2, 2020. The approximate locations of the explorations are shown on Figure 2, Site Plan. The procedures used to advance the test pits, collect samples, and other field techniques are described in detail in the following paragraphs. Unless otherwise noted, all soil sampling and classification procedures followed engineering practices in general accordance with relevant ASTM procedures. "General accordance' means that certain local drilling/excavation and descriptive practices and methodologies have been followed. A2 TEST PITS A2.1 Excavation Test pits were excavated using a Case 580 excavator equipped with a 24 -inch -wide, toothed bucket provided and operated by Dan J. Fisher Excavating, Inc., of Forest Grove, Oregon. The test pits were observed by a member of the PBS geotechnical staff, who maintained a detailed log of the subsurface conditions and materials encountered during the course of the work. A2.2 Sampling Representative disturbed samples were taken at selected depths in the test pits. The soil samples were examined by a member of the PBS geotechnical staff and sealed in plastic bags for further examination. A2.3 Test Pit Logs The test pit logs show the various types of materials that were encountered in the excavations and the depths where the materials and/or characteristics of these materials changed, although the changes may be gradual. Where material types and descriptions changed between samples, the contacts were interpreted. The types of samples taken during excavation, along with their sample identification number, are shown to the right of the classification of materials. The natural water (moisture) contents are shown farther to the right. Measured seepage levels, if observed, are noted in the column to the right. A3 MATERIAL DESCRIPTION Initially, samples were classified visually in the field. Consistency, color, relative moisture, degree of plasticity, and other distinguishing characteristics of the soil samples were noted. Afterward, the samples were reexamined in the PBS laboratory, various standard classification tests were conducted, and the field classifications were modified where necessary. The terminology used in the soil classifications and other modifiers are defined in Table A-1, Terminology Used to Describe Soil. PY` September 22, 2020 J A-1 PBS ProjeR'/3415.002002 Table A-1 PBS Terminology Used to Describe Soil loft Soil Descriptions Soils exist in mixtures with varying proportions of components. The predominant soil, i.e., greater than 50 percent based on total dry weight is the primary soil type and is capitalized in our log descriptions (SAND, GRAVEL, SILT, or CLAY). Smaller percentages of other constituents in the soil mixture are indicated by use of modifier words in general accordance with the ASTM D2488-06 Visual -Manual Procedure. "General Accordance' means that certain local and common descriptive practices may have been followed. In accordance with ASTM D2488-06, group symbols (such as GP or CH) are applied on the portion of soil passing the 3 -inch (75mm) sieve based on visual examination. The following describes the use of soil names and modifying terms used to describe fine- and coarse-grained soils. Fine -Grained Soils (50% or greater fines passing 0.075 mm, No. 200 sieve) The primary soil type, i.e., SILT or CLAY is designated through visual -manual procedures to evaluate soil toughness, dilatency, dry strength, and plasticity. The following outlines the terminology used to describe fine-grained soils, and varies from ASTM D2488 terminology in the use of some common terms. Plasticity Plasticity Primary soil NAME, Symbols, and Adjectives Description Index (PI) SILT (ML & MH) CLAY (CL & CH) ORGANIC SOIL (OL & OH) _ SRT Organic SILT Non -plastic 0-3 SILT Organic SILT Low plasticity 4-10 SILT/Elastic SRT Lean CLAY Organic SILT/ Organic CLAY Medium Plasticity 10-20 Elastic SILT Lean/Fat CLAY Organic CLAY High Plasticity 20-40 Elastic SILT Fat CLAY Organic CLAY Very Plastic >40 Modifying terms describing secondary constituents, estimated to 5 percent increments, are applied as follows: Description %Composition With Sand %Sand> -%Gravel —15%to 2S% plus No. 200 With Gravel %Sand<%Gravel _ Sandy _ % Sand >>% Gravel <30% to 50% plus No. 200 Gravelly %Sand <% Gravel Borderline Symbols, for example CH/MH, are used when soils are not distinctly in one category or when variable soil units contain more than one soil type. Dual Symbols, for example CL -ML, are used when two symbols are required in accordance with ASTM D2488. Soil Consistency terms are applied to fine-grained, plastic soils (i.e., PI > 7). Descriptive terms are based on direct measure or correlation to the Standard Penetration Test N -value as determined by ASTM D1586-84, as follows. SILT soils with low to non -plastic behavior (i.e., PI < 7) may be classified using relative density. Consistency SPT N -value Unconfined Compressive Strength Term tsf Very soft Less than 2 Less than 0.25 Less than 24 Soft 2-4 0.25 - 0.5 24-48 Medium stiff 5-8 0.5 - 1.0 48-96 Stiff 9-15 1.0 - 2.0 96-192 stiff 16-30 2.0 - 4.0 192-383 _Very Hard Over 30 Over 4.0 Over 383 BS Table A-1 Terminology Used to Describe Soil 2 of Coarse - Grained Soils (less than 50% fines) Coarse-grained soil descriptions, i.e., SAND or GRAVEL, are based on the portion of materials passing a 3 -inch (75mm) sieve. Coarse-grained soil group symbols are applied in accordance with ASTM D2488-06 based on the degree of grading, or distribution of grain sizes of the soil. For example, well -graded sand containing a wide range of grain sizes is designated SW, poorly graded gravel, GP, contains high percentages of only certain grain sizes. Terms applied to grain sizes follow. Material NAME SAND (SW or SP) GRAVEL (GW or GP) Additional Constituents:_ Cobble Particle Diameter 0.003-0.19 0.075-4.8 0.19-3-- 4.8-75 3-12 75-300 12-120 300-3050 The primary soil type is capitalized, and the fines content in the soil are described as indicated by the following examples. Percentages are based on estimating amounts of fines, sand, and gravel to the nearest 5 percent. Other soil mixtures will have similar descriptive names. Example: Coarse -Grained Soil Descriptions with Fines >5% to < 15% fines (Dual Symbols) k15% to < 50% fines Well graded GRAVEL with silt: GW -GM Silty GRAVEL: GM Poorly graded SAND with clay: SP -SC Silty SAND: SM Additional descriptive terminology applied to coarse-grained soils fallow. Example: Coarse -Grained Soil Descriptions with Other Coarse -Grained Constituents Coarse -Grained Soil Containing Secondary Constituents With sand or with gravel >- 15% sand or gravel With cobbles; with boulders Any amount of cobbles or boulders. Cobble and boulder deposits may include a description of the matrix soils, as defined above. Relative Density terms are applied to granular, non -plastic soils based on direct measure or correlation to the Standard Penetration Test N -value as determined by ASTM D1586-84. Relative Density Term SPT N -value Very loose 0-4 Loose 5-10 Medium dense 11-30 Dense 31-50 Very dense > 50 Table Key To Test Pit and Boring Log Symbols P B S SAMPLING DESCRIPTIONS A ( c m o c ie Fc o°y i m r c jo Q O� ° P Q O ¢ o a .��° m .%ay y mow` whFa h c h� z h� At -1-c' i 1 LOG GRAPHICS Soil and Rock Sampling Symbols Instrumentation Detail Lithology Boundary: - - - -"Ground Surface separates distinct units- Sample Well Can a _ d (i.e., Fill, Alluvium, >, Recovery r Bedrock) at q' Sample — Well Seal approximate depths Interval Well Pioe 1 inciated Piezometer o Soil -type or Material -type o _ _-_ Change Boundary: separates soil V —Well Screen - - Sampler and material chanes within the 9 Piezometer same lithographic unit at Type approximate depth indicated Bottom of Hole Geotechnical Testing Acronym Explanations PP Pocket Penetrometer HYD Hydrometer Gradation TOR Torvane SIEV Sieve Gradation DCP Dynamic Cone Penetrometer DS Direct Shear ATT Atterberg Limits DD Dry Density PL Plasticity Limit CBR California Bearing Ratio LL Liquid Limit RES Resilient Modulus PI Plasticity Index VS Vane Shear P200 Percent Passing US Standard No. 200 Sieve bgs Below ground surface OC Organic Content MSL Mean Sea Level CON Consolidation HCL Hydrochloric Acid UC Unconfined Compressive Strength Details of soil and rock classification systems are available on request. Rev.OV2on RIDGEVIEW GARDENS TEST PIT TP -1 SPRINGFIELD, OREGON PROJECTBER' APPROX. TEST PIT TP -I LOCATION '. Site PBSPBS _ ]31115.002 5.002 (See Pian) Ad 007030 Len9: -122.944314 e o'Hi CONE () a. W PENETROMETER DEPTH s m MATERIAL DESCRIPTION ? MSTATIC COMMENTS METQ O d y a. Edr 2OMOISTIIRE PENETRCMETER m 0 Llnes represent, the Merface Leal ati units of affairs; de6chp4m � F ,N are approamere only'ekmed where CONTENT% surface Conditions ones heMxenssinal and mWindsomaredual4ansNon, y ° 5D 100 GRAVEL FILL (16 inches) T .3 Hard, dark brown, lean CLAY (CL); medium plasticity; moist PP PP 4.5 t9 20 PP PP do WT 4.0 becomes very stili PP PP= 3.251sf Medium dense, brown to gray, silly 45 "r. GRAVEL (GM) with sand and cobbles; non -plastic; fine to coarse sand; fine to coarse, rounded gravel; moist 6.0 " A 8.0 becomes wet �ad Caving below 9 feet N, 100 P 12.0 20 sowon2c Final depth 12.0 feel bgs; test pit backfilled with excavated material to existing ground - surface. 140— h so f°° LOGGED BY: D. Eibert EXCAVATED BY: ban J. Hil Ercadall Inc. FIGUREAI COMPLETED: WOZn020 EXCAVATION METHOD: Case 500 With 24"Bucket Pagel oft RIDGEVIEW GARDENS TEST PIT TP -2 SPRINGFIELD, OREGON PPPROX. TEST PSI, TPon) OCATION: �� P65 PROJECT NUMBER: ]3415.002 Lat 44.046902 Long: -122.943]96 W M e DYNAMIC CONE z PENETROMETER DEPTH m C MATERIAL DESCRIPTION r R m STATIC COMMENTS FEET p Llnes bPMdB08piYmcM uni6M 4 (j w d Q PENETROMETER represen4n9lh.In�eil.ce �MOISTONE U' tltZin tl.00i me Ppwim'sle-Ni�dertetl where Q ✓+ CONTENT % sul18. CAntlitions: Gravel oe nfample5.e dmay lndl gmeue u2nston. m 0 50 100 -� t GRAVEL FILL (18 inches) 1'6 Hard, dark brown, lean CLAY (CL) with sand; medium plasticity; fine to medium 20 sand; moist PP - PIP -4.5IN �m PP PIP =45W 4.0 becomes very stiff PP PP 3.0 of Graytobrown,well-graded GRAVEL (GW) 45 with sand; fine to medium sand; fine to coarse, rounded gravel; moist5.5 eelrration ceslin9 competea at feet .:* P200 FOOD =3% �N 60 increased sand 8.0 : Eesierdii 45 F i Final depth feet test pit backfilled ted material t with excavated material to existing 12E redground surface. Groundwater not encountered at at time of exploration. s 14.0 a sa o0 S LOGGED BY: D. Eli EXCAVATED BY: Den J. Hi Ex<avaGng, Inc. FIGURE fit COMPLETED: 91OV2020 EXCAVATION METHOD: Case 580 Wth 24" Bucket P.ga of I RIDGEVIEW GARDENS TEST PIT TP -3 OW SPRINGFIELD, OREGON PBS PROJECT NUMBER APPROX TEST PIT TP -3 LOCATION: (Be. Site Plant �� _ 13415.002 Lot: 44.045168 Long: -122.943393 W O DYNPMICCONE aJ U. PENETROMETER DEPM u p MATERIAL DESCRIPTION r z l0 STATIC COMMENTS FEET p F W J¢ PENETROMETER (J Anes mpreseming Tlu mlertare Celween soivmG unl¢W w OMOISTURE belies sampai and may ind alr radUaleaea wtere beM1xen samples, and mey Intli�s1e 9�eEuel vanaltiort QV✓ CONTENT sMBCa COntli40na: Grana N p 50 1 s GRAVEL FILL (18 inches) 15 Hard, brown, lean CLAY (CL) with sand; 20 medium plasticity; fine to medium sand; moist PP PP=4.5 tat �as PIP - PP -4.5 of Hard, light brown, sandy SILT (ML); loco ss plasticity; fine to medium sand; moist - 40 PP PP=dS [af i' Gory, well -graded GRAVEL (GW-)wilh GM so silt, sand, and cobbles; non -plastic; fine to coarse sand; fine to coarse, rounded gravel; moist as 6.0 8.0 10.0 becomes moist to wet Y MIOW20 1�0 12'0 Final depth 12.0 feel bgs; test pit backfilled with excavated material to existing ground surface. 14.0 o m 100 LOGGED BY D. Eii EXCAVATED BY Dan J. Fame, Exrnafin9, Inc FIGUREA3 COMPLETED: 9104/2020 EXCAVATION METHOD: Case 580wtlh 24' Bucket pNel all RIDGEVIEW GARDENS TEST PIT TP -4 SPRINGFIELD, OREGON APPRO%. TEST PITLOCATION PBS PBS PROJECT Pla 2UMBER: Lal: 44 M6834 Lmhg:-122.944121 d O OYNAMIC CONE PENETROMETER DEPTH mcg MATERIAL DESCRIPTION r z Z� lO STATIC COMMENTS FEET O d PENETROMETER They representing the inlepaw bamy. eOmN[un'N M Ea LUJQ 6MOISTURE G ng ammo n are eppmxinate any, Infehea xRrere tliReno <�0 CONTENT% Surface Cedifims: Gravel behvesannUes, aM may indicate gradual vereltlan. en N p 50 100 GRAVEL FILL (12 inches) i' t t Very stiff, brown, lean CLAY (CL) with sand; medium plasticity; fine to medium sand; moist 2.0 PP - PP 4.0 to PP PP 2.0 h4 ATT �� : w LL 30 PL 21 PI =9 4.0 becomes stiff OR PP=total Gray, silty GROVEL (GM) with sand; as non -plastic; fine to coarse sand; fine to s.o coarse, rounded gravel; moist !. Gray, silty SAND (SM) with gravel; fi5 non -plastic; fine to medium sand; fine, rounded gravel; moist m e.o --------------------- Gray, well -graded GRAVEL (GW -GM) with gs silt and sand; non -plastic; fine to coarse 41.0 sand; fine to coarse, rounded gravel; moist 7 091OW20 becomes wet 12.0 2h Final depth 12.0 feet bgs; test pit backfilled with excavated material to existing ground surface. 14.0 b so Igo LOGGED BY: O. Elbert EXCAVATED BY: Dan J. FlsCrer Excavating. Inc FIGURE A4 COMPLETED: 9102G020 EXCAVATION METHOD: Case 580 with 24' Euclid Page 1 of 1 RIDGEVIEW GARDENS TEST PIT TPS _ SPRINGFIELD, OREGON PBS PROJECT NUMBER: '. APPROK TEST PIT TP -5 LOCATIONPBS Pla (See Siten) 73415.002 IaC44.046718 Lcng:-122943042 w O DYNAMIC CONE tJ Dr F W PENETROMETER DEPTH 10 MATERIAL DESCRIPTION = m STATIC COMMENTS FEET QQ O a h PENEIROmEfEa p'0, Lines usessersit, Ne rudene between suisnink units of dice, description O us iMOISTURE U` amapproxirrele oft infened u sre bebreen sameq e pindmaylneinsegreu9. dlwu.n. Ny CONTENT% Siat&ue Cend,hins. Grass a c FA 1. GRAVEL FILL (18 inches) e 's Very stiff to hard, lean CLAY (CL) with 20 sand; medium plasticity; fine to medium sand; moist PP PP -40 of PP PP=4.25 t51 zN 4.0 PP PP=35W G m)F welI-graded GRAVEL(GW-(M)with sa silt and sand; non -plastic; fine to warse sand; fine to Coarse, rounded gravel; moist 6.0 r O B.0 i 10.0 1f0 Final depth 11.5 feet bgs; test pit backfilled with excavated material to existing ground surface. Groundwater not encountered at 120 time of exploration. 14D s s0 too LOGGED BY: D Blued E%CAVATED BY: Dan J. Fischer ExcersMug, Inc. FIGURE A5 COMPLETED: WOMO20 aO VATIONMETHOD: Csse580,sh24"Bucket Papelcsl RIDGEVIEVJ GARDENS TEST PIT TP -6 SPRINGFIELD, OREGON APPROX. TEST PIT TPE LOCATION: PBS PROJECT NUMBER' (See Stle Plan) ]3415.002 Litt 44.OW522 Lang: -122.994350 Ipp O DYNAMIC CONE PENETROMETER DEPTH m O MATERIAL DESCRIPTION r z M STATIC COMMENTS FEET p F W PENETROMETER noes repiesemire me lmenwe Between smYon, units of w N *MOISTURE U' diRanng dmonption are apprex ieme Only,,memwhere F CONTENT% Smles ConEhione: Grose hemome sempies� and�reyiMicate g2tlusltA09N00. 0 `A 100 0.0 GRAVEL FILL (12 inches) 10 Hard, dark brown, lean CLAY (CL); medium plasticity; moist 2.0 PP RE 4.5 tsf Light brown, sandy SILT (MIL); low 30 PP=45tar plasticity; fine to medium sand; moist P200 P200=60% �N 4.0 PP PIP =45tar Gray to brown, silty GRAVEL (GM) with ss � % sand; non -plastic; fine to coarse sand; fine so .. to coarse, rounded gravel; moist 8.0 - P: ms Final depth 10.5 feet bgs; test pit backfilled with excavated material to existing ground surface. Groundwater not encountered at time of exploration. 12.0 14.0- 0 sg 'on li LOGGED BY: D. Elbert EXCAVATED BY: Can J. Fisher Excavating, Inc. FIGURE A6 COMR-ETE91022020 EXCAVATION METHOD: Case 580 with 24"Bucke0 Rosa," RIDGEVIEW GARDENS TEST PIT TP -7 we SPRINGFIELD, OREGON PBS PROJECT NUMBER: APPROX. TEST PIT Ple LOCATION: (See Site Plan) ® �� 3415.002 Lat 44.095503 Lag: -122.963762 a- s OVNPMIC GONE p PENETROMETER DEPTH -0 MATERIAL DESCRIPTION r i w m spec COMMENTS FEET O d F W Jg PENETROMETER Anes represeMirg the lMMaw loaaamn aoiYmck untls of •LONTEONr% G tliHanng cewnption are apluoumale only. intoye4 where aN $uRa¢ConGltlons:Grese hoomen samples, and may haeme rhad-I 4anctlion. N 0 50 1C0 Clayey GRAVEL FILL (30 inches) Rces and garhage bags encountered 20 25 Hard, brown, lean CLAY (CL) with sand; medium plasticity; fine to medium sand; moist PP PP-4stst an •- 4.0 PP PP=4.5 mf becomes sandy P200 P200=65% �a ' G raylobrown,welI< Faded GRAVEL s5 Ineltratlon all chancel at s fcetbgs (GW -GM) with silt and sand; non -plastic; 6.0 fine to coarse sand; fine to coarse, Pzoo Pz00=12% rounded gravel; moist to wet N � 8.0 '- .� Dark gray, well -graded GRAVEL (GW) with yD sand; fine to coarse sand; fine to coarse, rounded gravel; wet 10.0.: ar V yol 12.0 try Final depth 12.0 feet bgs; test pit backfilled with excavated material to existing ground surface. 14.0 0 50 100 LOGCI-o Bv: D. Eirna EXCAVATED BY Dan J. Ranter E.Taval Inc. FIGURE A7 COMPLETED: Wy22D20 EXCAVATION METHOD. Case MO with 24" Bucket Pey.I at RIDGEVIEW GARDENS TEST PIT TP -8 SPRINGFIELD, OREGON APPROX. TEoas1t LOCATION: �� PBS PROJECTN MBER: ph tat 44.046491 Long : -122943250 LL� 9DYNAMICCONE Z Zw PENETROMETER DEPTH mG MATERIAL DESCRIPTION Ea mS the COMMENTS FEET �� d r N W;1 P PENETROMETER Llnesre Pel tie ant soiYmad ante of •CONTENT% G desenlin9 dlBemg descdplionareapplmimale only.Inkrtetl wM1ea approd F QVa Smkce Coldii Glassy bslwsen—pks, and may indicate gradual trensi MU. y 0 W 100 GRAVEL FILL (18 inches) I� i' s Hard, brawn, lean CLAY (CL) with sand; medium plasticity; fine to medium sand; 20 moist PP PP=4.5 mf �m PP PP=4.5 tar 4.0 PP PP=4.5 tar Gray to brown, silty GRAVEL (GM) with 05 sand; fine to coarse sand; fine to coarse, rounded gravel; moist m 6.0 8.6 Gray, well -graded GRAVEL (GW -GM) with ao silt, sand, and cobbles; non -plastic; fine sand; fine to coarse, rounded gravel; moist 19.0 110 Final depth 11.0 feet bgs; test pit backfilled with excavated material to existing ground surface. Groundwater not encountered at 12.0 time of exploration. 14.0 o w 100 'i LOGGED BY: D. E 01 EXCAVATED BY: Dan J. Daarer Evaveting, Iw, F I G LI RE A8 COMPLETED: WOM020 EXCAVATION METHOD: Cans 500 with 24" Bucket Pat. t W i Appendix B Laboratory Testing Geotechnical Engineering Report Ridgeview Gardens, LLC Appendix B: Laboratory Testing Ridgeview Gardens B1 GENERAL Samples obtained during the field explorations were examined in the PBS laboratory. The physical characteristics of the samples were noted and field classifications were modified where necessary. During the course of examination, representative samples were selected for further testing. The testing program for the soil samples included standard classification tests, which yield certain index properties of the soils important to an evaluation of soil behavior. The testing procedures are described in the following paragraphs. Unless noted otherwise, all test procedures are in general accordance with applicable ASTM standards. "General accordance' means that certain local and common descriptive practices and methodologies have been followed. B2 CLASSIFICATION TESTS B2.1 Visual Classification The soils were classified in accordance with the Unified Soil Classification System with certain other terminology, such as the relative density or consistency of the soil deposits, in general accordance with engineering practice. In determining the soil type (that is, gravel, sand, silt, or clay) the term that best described the major portion of the sample is used. Modifying terminology to further describe the samples is defined in Table A-1, Terminology Used to Describe Soil, in Appendix A. B2.2 Moisture (Water) Contents Natural moisture content determinations were made on samples of the fine-grained soils (that is, silts, clays, and silty sands). The natural moisture content is defined as the ratio of the weight of water to dry weight of soil, expressed as a percentage. The results of the moisture content determinations are presented on the exploration logs in Appendix A and on Figure B2, Summary of Laboratory Data, in Appendix B. 1112.3 Atterberg Limits Atterberg limits were determined on select samples forthe purpose of classifying soils into various groups for correlation. The results of the Atterberg limits test, which included liquid and plastic limits, are plotted on Figure B1, Atterberg Limits Test Results, and on the exploration logs in Appendix A, where applicable. B2.4 Grain -Size Analyses (P200 Wash) Washed sieve analyses (P200) were completed on samples to determine the portion of soil samples passing the No. 200 Sieve (i.e., silt and clay). The results of the P200 test results are presented on the exploration logs in Appendix A and on Figure B2, Summary of Laboratory Data, in Appendix B. PBS September 22, .020 �` �/6J B-1 PBS Project ]3415.002 0011h PBS SAMPLE NUMBER ATTERBERG LIMITS TEST RESULTS 5050 MAIN STREET SPRINGFIELD, OREGON PBS PROJECT NUMBER: 1 73415.002 m 50 n 40 9C 10 0k 0 CL or ML TEST METHOD: ASTM D4318 LIQUID LIMIT MH KEY EXPLORATION NUMBER SAMPLE NUMBER SAMPLE DEPTH (FEET) NATURAL MOISTURE CONTENT (PERCENT) PERCENT PASSING NO. 40 SIEVE (PERCENT) LIQUID LIMIT PLASTIC LIMIT PLASTIC ITV INDEX • TPA S-1 3.0 24.1 NA 30 21 9 FIGURE B1 P�e1 N1 am3w PBS SUMMARY OF LABORATORY DATA 5050 MAIN STREET SPRINGFIELD. OREGON PES PROJECT NUMBER' 73415.002 SAMPLE INFORMATION MOISTURE CONTENT (PERCENT) DRY DENSITY (PCF) SIEVE ATTERBERG LIMITS EXPLORATION NUMBER SAMPLE NUMBER SAMPLE DEPTH (FEET) ELEVATION (FEET) GRAVEL IpERCEM) SAND (PERCENT) RCE (PERCENT) LIQUID LIMIT IpERCENT) PLASTIC LIMIT (PERCENT) PLASTICITY INDEX (PERCENT) TP -1 S-1 2 15.2 TP -2 S-1 2.5 16.5 TP -2 S-2 5.5 9.4 3 TP -3 S-1 2 15.0 TPA S-1 3 24.1 30 21 9 TPS 5-1 3 25.2 TPA S-1 3.5 16.2 60 TP-] S-1 35 16.9 TP -7 5-2 5 20.5 65 TPA 5-1 2.5 172 FIGURE B2 Page i o(1 $PWIPi6Fl6U PUBLIC WORKS DEPARTMENT / Engineering Division Phone: (541) 726-3'753 Fax: (541) 736-1021 STORMWATER MANAGEMENT SYSTEM SCOPE OF WORK --- (Area belon' this J!" iffed out by Applicant) --- 'Please return to Matt Stoader@, Cig, ofSprinvOeM Public Works L+ngineeeingr F"# 736-1077, Phone # 7366-]035,} Project Name: Ridgeview Gardens Apartments Applicant: A&p Engineering LLC Assessors Parcel #: 17-02-33-32-3800 "Date: 8,11112020 Land. Use (a): Multi -Family Residential Phone #: (541) 302-9790 Project 84Aeres): 1.98 acres Fax #: Approx. Impervious Area: 1.5 acres Email: kylemovis(a3ao-engrcrom Project Description (Include a copy of Assessor's map): The proposed project Is to construct an apartment complex (approximately 54 units) with private infrastructure such as drives, parking and utilities. Drainage Proposal (Public connection(s), discharge location(s), etc. Attach additional sheets) if necessary: It is proposed to construct vegetative stonnwaler treatment facilities (rain gardens, swaies or storm planters) to treat and convey slonnwater runoff from the impervious pavement surfaces. Proposed discharge locations are infiltration (if site soils allow) anchor public storm main on the north side of Main Street. Proposed Stormwater Best Management Practices: A vegetated facility (swale, rain garden or planter) is proposed to treat stormwater runoff from the Impervious oavement. Infiltration will be utilized from this facility if possible. -- (Area below this tine ftRedout brthe. Car and Retnrned to theAiytAcui — (At a minwatn, of? )naxes checked by the CIO on the front and backofthis sheetsh ill he,subadtted for an opphration to he camplere for ,submittal, although ad" requinweNU mac be necessary) Drainage Study Tree (EDSPM Section 4.03.2): (Note, UH may be substituted for Rational Method) ❑ Small Site Study– (use Rational Method for calculations) Mid -Level Development Study– (use Uuut Hydrogaph Method for cahvlations) Full Drainage Development Study– (use Unit Hydrograph Method for calculations) Environmental Considerations: [9 Wellhead Zone: -EZ �% 9 I, ear` ❑ Hillside Development: ❑ Wetland/Riparian: A/))Sa t ❑ FioodwayFloodplain: P/t4 [jio Soil Type: lan4 ❑ Other Jurisdictions: Downstream Attja jis dx cY UPLM lend ® NIA -- t lc; c rB)reWsi canpedNro Criss- S7'utn %x,rcw M rw � .l tr,. til, u CahAetarb ❑ Flow line for starting water surface elevation: ❑ Design HGL to use for starting water surface elevation: ❑ Manhole/Junction to take analysis to: Return to Hatt Stouder !a": Citv of Springfield, email: mstouderi&:ci.s rin lield.or.us, FAR: (547) 736-1021 COMPLETE STUDY ITEMS r° °m°'^1Le 0n1yi a Based upon the rnfonaraion provided on the front of Phis .shecl, rhe h+flmwing represent' a mininuon of n -hot is needteffi,n un apphcadon to be contplele for suhmiltaf with respect to dnamage: however, this list should nor be used in lieu of'the Springfield Uevelnpn+mn! Cude (SDC) or the CiOb Fnginening Derfgn ,Manual. Cnmpltance with Chase +'egairements does rat consdhds si>e approval: Additional site spedffc infornunfan mar be required Note: Upon scoping shier sohorlsal, ensure completed fmm how been signed in the space provided below: Interim Design Standards/Water Quality (EDSP:vi Chapter 3) Req'd NIA ® ❑ Ali non -build ng rooftop (VBR) impervious surfaces shall be pre-treated (e.g. multi-chambered catchbasin Well filtration media) for stormwater quality. Additionally, a minimum of 50%of the NBR impervious surface shall be treatedby vegetated methods. .] ❑ Where required, vegetative stormwater design shall be consistent with interim design standards (EDSPM Section 3.02), set forth by the Bureau of Environmental Services (BES) or Clean Water Services (CWS). ❑ For new TBR impervious area Ins than 15,000 square feet, a simplified design approach may be followed as specified by die BES for vegetative treatment. ❑ If a stormwater treatment swale is proposed, submit calculations/specifications for sizing, velocity, flow, side slopes, bottom slope, and seed mix consistent with either BES or CWS requirements. ❑ Water Qualdy calculations as required in Section 3,03.1 ofthe EDSPM ❑ All building rooftop mounted equipment, or other fluid containing equipment located outside of [[to building, shall be provided with secondary cum sinment or weather resistant enclosure. General Study Requirements (EDSPA•I Section 4.03) ❑ Drainage study prepared by a Professional Civil Engineer licensed in the state of Orcgon. ❑ A complete drainage study, as required in EDSPM Section 4.03.1, including a hydrological study map. ® ❑ Calculations showing system capacity for a 2 -year storm event and overflow effects of a 25 -year storm event. ® ❑ The time of concetshetion (Tc) shall be determined using a 10 minu4 start time for developed basins. Review of Downstream System (EDSPM Section 4.03.4.0) ❑ P9 A downstream drainage analysis as described in EDSPM Section 4.03A.C. On-site drainage shall be governed by the Oregon Plumbing Specialty Code (OPSC). ❑ ® Elevations ofthe HOT. and flow lines for both pity and private systems where applicable. Design of Storm Systems (EDSPhf Section 4.04) ❑ Plow lines. slopes, rim elevations, pipe type and sizes clearly indicated on the plan act. ❑ Minimum pipe cover shall be 18 inches for reinforced pipe and 36 inches for plain concrete and plastic pipe materials, or proper engineering calculations shall be provided when less. The cover shall be sufficient to support an 80,000 Ib load without failure of the pipe structure. ❑ Meaning's "n" values for pipes shall be consistent with Table 4-1 of the EDSP. All soot pipes shall be designed to achieve a minimum velocity of three (3) feat per second at 0.5 pipe full based on Table 4-1 as well. Other/Mise ❑ Existing and proposed contours, located at one tont interval. Include spot elevations and site grades showing how site drains ® ❑ Private stormwater casements shall be clearly depicted on plans when private stormwater flows from one property to another KI ❑ Drywel Is shall not receive runoff l om any surface who being treated by one or more BMPs, with the exception of residential building roofs (EDSP Section 3.03.4.A). Additional provisions apply to this as required by the DEQ. Refer to the website•. •lea tate11ys ' I e hm for more information. N ❑ Detention ponds shall be designed to limit runoff to pre -development miss for the 2 through 25 -year storm events *This form shall be included as an anaehmenr, inside the front cover, of the.normwaler,andy `I:NPORTANT: EA'Gf.1EER PLEASE READ BELOW AND SICNI As the engineer of record, 14 hereby certify the above required items are complete and included with die submitted stormwater study and plan set. Signature: Date:/�lL �2e 2c, i r