servicing & swm brief sept-24-13

SERVICING & STORMWATER MANAGEMENT BRIEFBLOSSOM PARK PHARMACY

2928 BANK STREETOTTAWA, ONTARIO

Dobri Engineering Ltd.PO Box 441Port Hope, OntarioL1A 3Z3Phone No. 905-885-2881E-mail [email protected]

REVISED SEPTEMBER 24, 2013

Servicing & Stormwater Management Brief, Blossom Park Pharmacy, 2928 Bank Street, OttawaRevised September 24, 2013

- 1 -

This report has been revised to address comments received from the City. Specifically,the building use and fire protection information has been added.

PROJECT DESCRIPTION

Dobri Engineering Ltd. has been retained to prepare a Stormwater Management Brief insupport of a Site Plan Control Approval for Blossom Park Pharmacy, located on 2928Bank Street in Ottawa. Following the submission of the SWM Brief, municipal staffrequested a consultation meeting to discuss the submission. At the meeting on April 10,2013, the staff noted that a Servicing Brief to estimate the water demand and sewage flowwas also required for the proposed re-development. This report has been prepared toconsolidate the information submitted to date in accordance with the City’s ServicingStudy Guidelines for Development Applications.

The subject property is an existing commercial site at the municipal address of 2928Bank Street, Ottawa. The property is located in the northwest corner of the intersection ofBank Street and Queensdale Avenue (see Key plan). The proposed re-development willincrease the size of the building, expanding the commercial component and adding aresidential apartment. The property covers a total area of 0.139 hectares, with 17.39mfrontage on Bank Street and 39.7m frontage on Queensdale Avenue. Access onto the siteis via Queensdale Avenue near the western limit of the property.

The Zoning Map illustrates the current zoning of the adjacent lands. The abuttingproperty to the north is commercial and the abutting property to the west is residential. Ashopping mall is located across the street, on the south side of Queensdale Avenue.

EXISTING SERVICING

Municipal services to the property are available on Queensdale Avenue. A 450mmdiameter concrete sanitary sewer and a 150mm diameter watermain are located on thesouth side of the roadway, and a 450mm diameter concrete storm sewer is locatedadjacent the curb line on the north side of the road. The existing Pharmacy is presentlyserviced with a 125mm diameter sanitary line and a 20mm diameter copper water line.These are illustrated on the Grading & Servicing Plan, Drawing No. SPA-3.

Flow calculation: The theoretical sewage flow was estimated using the Ottawa SewerDesign Guidelines, Appendix 4-A. The building usage is a Pharmacy on the ground floor,accounting firm and professional offices on the second floor (220 sq.m), mezzanine (88sq.m) and 3rd floor (189.9 sq.m). The total office floor area will be 497.9 sq.m. The dailysewage flow for each of the above uses is tabulated below.


- 2 -

Use Description Flow (l/day)Pharmacy Staff – 5 @ 75 l/staff/day 375*Office 497.9 sq.m @ 75l per 9.3 sq.m floor

area4,015

TOTAL 4,390* Estimated existing daily flow.

The total sewage flow is calculated at 4390 litres/day. The daily flow from each of theuses noted would be generated over differing time periods. The residential flow over a 12to 14 hour period, the medical office over an 8 hour period, and the pharmacy over a 10hour period.

A conservative estimate is to generate the total daily flow over an 8 hour period, for anaverage flow of 0.15 l/sec. The peaking factor can vary substantially, depending on thetype of usage (commercial, residential, industrial etc.). Using a conservative peakingfactor of 5 for the redevelopment, results in a theoretical peak water demand and peaksewage flow of 0.76 l/sec.

The existing (20mm) water service is capable of providing the estimated peak waterdemand. If necessary, a water storage tank could be installed in each of the units, toensure that an adequate water supply and pressure is available for peak instantaneousdemand needs. The mechanical consultant should re-evaluate the water demand once thefinal building use is determined.

A sprinkler system will not be installed in the building since it isn’t mandatory. Fireprotection will be provided by the existing municipal water distribution system whichservices the adjacent properties. This includes the shopping mall across QueensdaleAvenue.

Based on normal construction practice, the existing 125mm sanitary service line wouldbe installed with a 2% slope, and thus have a capacity of 7.4 l/sec. The theoretical peakflow is less than the pipe capacity. It should be noted that a 125mm PVC pipe installedwith a 1% slope has a capacity of 10.1 l/sec, which exceeds the calculated peak flow.

Although the daily water consumption and sewage flows will be substantially increasedby the re-development based on this analysis, the existing water service and sanitaryservice is adequate for the project. The water and sanitary services do not need to bereplaced.


- 3 -

STORMWATER MANAGEMENT

The property covers a total area of 0.139 hectares. A topographical survey of theproperty was completed by Farley Smith & Denis Surveying Ltd.. The existingdevelopment conditions are illustrated on Drawing No. 13-467-PRE. The proposed re-development is illustrated on Drawing No. 13-467-POST.

STORMWATER QUANTITY ANALYSIS

The development of this site will increase the overall runoff coefficient, as a result of theincreased impervious surface (roadway, driveways, and buildings). The analysis for thesurface water runoff is based on the following:

1. IDF data (graph) for City of Ottawa:

Return Tc IPeriod (min) (mm/hr)

2-yr 20 52.0

2-yr 10 77.05-yr 10 104.010-yr 10 120.025-yr 10 145.050-yr 10 161.0100-yr 10 180.0

2. Rational Method Qp = CIA/3603. Runoff Coefficient of 0.30 for landscaped areas4. Runoff Coefficient of 0.95 for paved surface, concrete and building roof5. Stormwater Management Planning & Design Manual, March 2003, Ministry of the

Environment6. Sawmill Creek Subwatershed Study, completed by CH2M Hill Canada Limited

EXISTING-DEVELOPMENT CONDITIONS

Calculate C, the runoff coefficient for the property (Existing-Development).

Surface Area (sq.m) C A x CImpervious 997 0.95 947.15Pervious 396 0.30 118.8

TOTAL 1393 1065.95

The average runoff coefficient, C is 0.77 for the existing site conditions.


- 4 -

POST-DEVELOPMENT CONDITIONS

Calculate C, the average runoff coefficient for the property (Post-Development).

Surface Area (sq.m) C A x CImpervious 1215 0.95 1154.25Pervious 178 0.30 53.4

TOTAL 1393 1207.65

The average runoff coefficient, C is 0.87 for post-development conditions. For designpurposes, use Tc = 10 minutes for the analysis.

Calculate the peak discharge using the Rational Method.

Peak Runoff Qp = CIA/360 Where Qp = peak runoff, cms C = runoff coefficient I = rainfall intensity, mm/hr A = area, hectares

The peak flow permitted is calculated in accordance with the Sawmill CreekSubwatershed Study and as confirmed by correspondence from the Rideau ValleyConservation Authority (RVCA).The peak discharge off site is to be limited to the flowfrom the 2-yr storm event, using a time of concentration of 20 minutes and a runoffcoefficient of 0.5.

Qp = CIA/360 = 0.5 x 52 x 0.1393/360 = 0.010 cms

Without any stormwater quantity controls, the peak discharge for Post-Developmentconditions is as follows:

Ottawat= 10.00 minutes C= 0.87 A= 0.139

2-yr 5-yr 10-yr 25-yr 50-yr 100-yrI= 77.00 104.00 120.00 145.00 161.00 180.00Q= 0.026 0.035 0.041 0.049 0.054 0.061

The Post-development flows must be limited to 0.010 cms. The minimum water storagerequired is the difference between the controlled outlet flow and the post developmentflows multiplied by the time of concentration. In this case (t= 10 minutes), the storagerequirement is 30.5 cubic metres to control the discharge during the 100-yr storm event to0.010cms. The required storage can be provided underground.


- 5 -

The stage-storage-discharge for other time increments is tabulated below for the 100-yrstorm event.

CONTROL DISCHARGE TO 0.010 Qp(cms)

100-YEAR TOTAL FLOW

AREA 0.139TIME INT (l) Qp RUNOFF DISCHAR STOR(min) (mm/hr) (cms) VOL (m3) VOL (m3) VOL (m3)

5 243.00 0.082 24.7 3.0 21.710 180.00 0.061 36.5 6.0 30.515 147.00 0.050 44.7 9.0 35.720 120.00 0.041 48.7 12.0 36.725 105.00 0.036 53.3 15.0 38.330 92.00 0.031 56.0 18.0 38.035 83.00 0.028 58.9 21.0 37.940 75.00 0.025 60.9 24.0 36.945 69.00 0.023 63.0 27.0 36.050 64.00 0.022 64.9 30.0 34.955 59.00 0.020 65.8 33.0 32.860 56.00 0.019 68.2 36.0 32.2

In order to control the site peak discharge to 0.010 cms (10 l/sec), the maximum storagerequirement of 38.3 cu.m.

Using a StormTech SC-740 chamber system as noted on the plan, 15 chambers willprovide a storage 37.5 cu.m. The chamber end caps, storm sewer pipe and stormstructures will provide the additional storage volume required. Product literature on theStormTech SC-740 chamber is provided in the appendix.

Stormwater discharge from the development will be controlled via an orifice plate on thestorm sewer outlet pipe. The minimum orifice opening permitted is 75mm diameter. Atthe maximum water level elevation in the chamber, the 75mm diameter orifice willcontrol the discharge to 0.010 cms.

The orifice equation was used to calculate the outlet flow.Q = CA(2gH)1/2

Where Q is the flow in cubic metres per secondC is the orifice coefficient = 0.6A is the cross sectional area of the orifice opening in square metresg is acceleration due to gravity = 9.81 m/s2

H is the driving head measured from the water surface to the centroid ofthe opening in metres


- 6 -

To discharge the permitted flow, the head is 0.76m. This driving head will be exceededfor the 25-yr or greater storm event. At the maximum head of 1.07m occurring during the100-yr storm event, the discharge through the orifice will be 0.012 cms, which marginallyexceeds the permitted discharge.

STORMWATER QUALITY ANALYSIS

The Sawmill Creek Subwatershed Study notes that a SWM facility will be constructeddownstream of the site in order to provide stormwater quality control for the catchmentarea. While quality control is not required for the re-development of this site, the reportdoes recommend it. It should be noted that some municipalities and conservationauthorities do not require quality control on small sites (ie: where the pavement area isless than 2500 sq.m.).

Stormwater quality control can be provided via infiltration. From Table 3.2 in the MOEguidelines, in order to provide an enhanced level of protection (80% SS removal), aninfiltration system would need to provide 40 cu.m of storage per hectare of drainage areahaving an 85% impervious level. For this site 5.56 cu.m of storage is required.

The proposed StormTech chamber system will provide a minimum 3.09 cu.m of storageunder the chambers (40% void ratio for 50mm clear stone). Additional storage isprovided within the stone surrounding the chambers.

APPENDIX

Ottawa Sewer Design Guidelines

APPENDIX 5-A OTTAWA INTENSITY DURATION FREQUENCY (IDF) CURVE

City of Ottawa October 2012

APPENDIX 5-A

OTTAWA INTENSITY DURATION FREQUENCY (IDF) CURVE

Ottawa Sewer Design Guidelines

APPENDIX 5-A OTTAWA INTENSITY DURATION FREQUENCY (IDF) CURVE

City of Ottawa Appendix 5-A.1 October 2012

StormTech SC-740 Chamber

Call StormTech at 888.892.2694 for technical and product information or visit www.stormtech.com 9

90.7" (2300 mm)

51.0" (1295 mm)

85.4" (2170 mm) INSTALLED

ACCEPTS 4" (100 mm) SCH 40 PIPE FOR OPTIONALINSPECTION PORT

30.0"(762 mm)

8"(203 mm) 24" (610 mm) DIA. MAX

SC-740 End Cap

SC-740 Chamber

StormTech SC-740 Chamber (not to scale)

Nominal Chamber Specifications

Size (L x W x H) 85.4" x 51.0" x 30.0" (2170 x 1295 x 762 mm)

Chamber Storage 45.9 ft3 (1.30 m3)

Min. Installed Storage* 74.9 ft3 (2.12 m3)

Weight 74.0 lbs (33.6 kg)

Shipping

30 chambers/pallet

60 end caps/pallet

12 pallets/truck

Designed to meet the most stringent industry performance standards for superior structural integrity while providingdesigners with a cost-effective method to save valuableland and protect water resources. The StormTech system is designed primarily to be used under parkinglots thus maximizing land usage for commercial and municipal applications.

SC-740 Chamber

*Assumes 6" (152 mm) stone above, below and between chambers and 40% stone porosity.

CHAMBERS SHALL BE DESIGNED IN ACCORDANCE WITHASTM F2787 “STANDARD PRACTICE FOR STRUCTURALDESIGN OF THERMOPLASTIC CORRUGATED WALLSTORMWATER COLLECTION CHAMBERS.”

CHAMBERS SHALL MEET THE REQUIREMENTSOF ASTM F2922 (POLYETHYLENE CHAMBERS)

OR ASTM F2418 (POLYPROPYLENE CHAMBERS)

NOMINAL 3/4" - 2" (19 mm - 51 mm)CLEAN, CRUSHED, ANGULAR STONE

(AASHTO M43 #3 THROUGH #57STONE SIZES ALLOWED)

ADS 601T NON-WOVEN GEOTEXTILE(OR EQUAL) ALL AROUND

CLEAN, CRUSHED,ANGULAR STONE

StormTech SC-740 Chamber

10 Call StormTech at 888.892.2694 for technical and product information or visit www.stormtech.com

42 (1067) 45.90 (1.300) 74.90 (2.121)41 (1041) 45.90 (1.300) 73.77 (2.089)40 (1016) 45.90 (1.300) 72.64 (2.057)39 (991) 45.90 (1.300) 71.52 (2.025)38 (965) 45.90 (1.300) 70.39 (1.993)37 (948) 45.90 (1.300) 69.26 (1.961)36 (914) 45.90 (1.300) 68.14 (1.929)35 (889) 45.85 (1.298) 66.98 (1.897)34 (864) 45.69 (1.294) 65.75 (1.862)33 (838) 45.41 (1.286) 64.46 (1.825)32 (813) 44.81 (1.269) 62.97 (1.783)31 (787) 44.01 (1.246) 61.36 (1.737)30 (762) 43.06 (1.219) 59.66 (1.689)29 (737) 41.98 (1.189) 57.89 (1.639)28 (711) 40.80 (1.155) 56.05 (1.587)27 (686) 39.54 (1.120) 54.17 (1.534)26 (660) 38.18 (1.081) 52.23 (1.479)25 (635) 36.74 (1.040) 50.23 (1.422)24 (610) 35.22 (0.977) 48.19 (1.365)23 (584) 33.64 (0.953) 46.11 (1.306)22 (559) 31.99 (0.906) 44.00 (1.246)21 (533) 30.29 (0.858) 41.85 (1.185)20 (508) 28.54 (0.808) 39.67 (1.123)19 (483) 26.74 (0.757) 37.47 (1.061)18 (457) 24.89 (0.705) 35.23 (0.997)17 (432) 23.00 (0.651) 32.96 (0.939)16 (406) 21.06 (0.596) 30.68 (0.869)15 (381) 19.09 (0.541) 28.36 (0.803)14 (356) 17.08 (0.484) 26.03 (0.737)13 (330) 15.04 (0.426) 23.68 (0.670)12 (305) 12.97 (0.367) 21.31 (0.608)11 (279) 10.87 (0.309) 18.92 (0.535)10 (254) 8.74 (0.247) 16.51 (0.468)9 (229) 6.58 (0.186) 14.09 (0.399)

Depth of Water Cumulative Total System in System Chamber Storage Cumulative Storage

Inches (mm) Ft3 (m3) Ft3 (m3)

SC-740 Cumulative Storage Volumes Per ChamberAssumes 40% Stone Porosity. Calculations are BasedUpon a 6" (152 mm) Stone Base Under the Chambers.

StoneCover

Note: Add 1.13 cu. ft. (0.032 m 3) of storage for each additionalinch (25 mm) of stone foundation.

Amount of Stone Per Chamber

Note: Assumes 6" (152 mm) of row separation and 18" (457 mm) ofcover. Volume of excavation will vary as depth of cover increases.

Volume of Excavation Per Chamber yd3 (m3)Stone Foundation Depth

6" (152 mm) 12" (305 mm) 18" (457 mm)StormTech SC-740 5.5 (4.2) 6.2 (4.7) 6.8 (5.2)

Note: Assumes 6" (152 mm) of stone above chambers, 6" (152 mm)row spacing and 40% porosity.

Storage Volume Per Chamber ft3 (m3)Bare Chamber and Stone

Chamber Stone Foundation DepthStorage in. (mm)ft3 (m3) 6 (152) 12 (305) 18 (457)

StormTech SC-740 45.9 (1.3) 74.9 (2.1) 81.7 (2.3) 88.4 (2.5)

Note: Assumes 6" (150 mm) of stone above, and between chambers.

Stone Foundation DepthENGLISH TONS (yd3) 6" 12" 18" StormTech SC-740 3.8 (2.8 yd3) 4.6 (3.3 yd3) 5.5 (3.9 yd3)

METRIC KILOGRAMS (m3) 152 mm 305 mm 457 mmStormTech SC-740 3450 (2.1 m3) 4170 (2.5 m3) 4490 (3.0 m3)

8 (203) 4.41 (0.125) 11.66 (0.330)7 (178) 2.21 (0.063) 9.21 (0.264)6 (152) 0 6.76 (0.191)5 (127) 0 5.63 (0.160)4 (102) 0 4.51 (0.125)3 (76) 0 3.38 (0.095)2 (51) 0 2.25 (0.064)1 (25) 0 1.13 (0.032)

Depth of Water Cumulative Total System in System Chamber Storage Cumulative Storage

Inches (mm) Ft3 (m3) Ft3 (m3)

Stone Foundation

SC-740 Cumulative Storage Volumes Per Chamber (cont.)

servicing & swm brief sept-24-13

Documents