SWM DESIGN BRIEF. ASCENSEUR REGIONAL 1519, StarTop Road Ottawa, Ontario File number 2013-DRA-804 Reviewed July 31st,2013

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1 SWM DESIGN BRIEF ASCENSEUR REGIONAL 1519, StarTop Road Ottawa, Ontario File number 2013-DRA-804 Reviewed July 31st,2013 Document prepared by Richard Bélec, p.eng.

2 SWM DESIGN BRIEF OTTAWA REGIONAL ELEVATOR 1519, StarTop Road, Ottawa File number 2013-DRA-804 Reviewed July OJECTIVE 2. SURVEY PLAN 3. ROAD WIDENING REQUIREMENTS TABLE OF CONTENT 4. PRE AND POST DEVELOPMENT SITE PLANS 4.1 Sanitary and water services 4.2 Storm drainage facilities 4.3 IDF Curves 4.4 Time of concentration 4.5 Modified Rational Method for Storage 4.6 Pre and Post development surface runoff coefficient 4.7 Sediment control 5. CONCLUSION AND RECOMMENDATION APPENDIX - A Storm Water Management Study Pre and Post Development Drainage System PLAN SCHEDULE: DETAILS-1/3 PREDEV-2/3 POSTDEV-3/3 IMPORTANT NOTES AND DETAILS STORMCEPTOR STC-300I PRE-DEVELOPMENT DRAINAGE SYSTEM POST DEVELOPMENT DRAINAGE SYSTEM APPENDIX - B IDF Curves Environment Canada APPENDIX - C Modified Rational Method for Storage Computations For 5 and 100 Years Short Storms APPENDIX - D Stormwater Quality Objectives Stormceptor STC-300i Details and cross sections Computer Output APPENDIX - E Survey Plan by Farley, Smith & Denis Surveying Ltd

3 SWM DESIGN BRIEF OTTAWA REGIONAL ELEVATOR 1519, StarTop Road, Ottawa File number 2013-DRA-804 Reviewed July OJECTIVE Ottawa Regional Elevator is already located at 1519 Star Top road in Ottawa where they actually operate a commercial business into elevator assemblies, maintenance and delivery. Because of expansion requirements, the business need more space for their operations and storage facilities. Actually, there are two building on the site, one with a commercial character which is used for their daily operation and a second with a residential character which is used as a storage facility. The project submitted to the City of Ottawa proposes the demolition of the residential building to be replaced by a new commercial one which would be connected to the actual commercial building. Sagenex Inc, as an engineering firm, was hired by BBL Construction to prepare the structural concept of this new building with the grading and drainage plan which is the principle objective of this report. Comments regarding the actual site servicing facilities are also addressed. 2. SURVEY PLAN The pre and post development site plan where prepared from the Survey Plan prepared by Farley, Smith & Denis Surveying Ltd under File number dated December 23 rd, 2011, which is included into Appendix E. Legend and Additional Information symbols where respected and referenced on the pre and post development site plans StarTop road is Part of West Lot 24, Concession 2 (Ottawa Front) Geographic Township of Gloucester, City of Ottawa 3. ROAD WIDENING REQUIREMENTS No road widening will be required since the distance from the paved center line of Star Top Road to the front property line is 13 meters as required. Distance was confirmed on site and by the land surveyor.

4 SWM DESIGN BRIEF OTTAWA REGIONAL ELEVATOR 1519, StarTop Road, Ottawa File number 2013-DRA-804 Reviewed July PRE AND POST DEVELOPMENT SITE PLANS Appendix A contains the scaled pre and post development plan showing the existing and proposed facilities attached to the existing commercial building. Proposed works are drawn with thicker lines than the existing. 4.1 Sanitary and water services Sanitary and water services are actually present on site. Both actual residential and commercial type building are being serviced by what was originally constructed for the dwelling needs. Both conduits where excavated and located and are showed on the post-development site plan. Calculations indicate that both sanitary and water pipes are sufficient to fulfill the needs for the new project although, the sanitary service pipe which is in bad condition will be abandoned and rebuilt according to City of Ottawa technical requirements. The daily average consummation was established as follow: Description L/Cap/d L/d Employees Office Clients Total daily needs 1700 Peak factor 5 Q daily average flow (Lpm) 1.18 Q daily peak flow (Lpm) 5.90 Total loss including pipe friction and head loss should reach a maximum of 2 meters for a daily peak flow of 5.9 Lpm. The existent 19 mm water service will be of sufficient capacity. 4.2 Storm drainage facilities Storm drainage facilities are inexistent on the site. The actual buildings do not have any basement, the foundation being below the freezing depth. Originally the drain tiles where connected to the old ravine that used to travel across Star Top road before it was canalized with a multi-plate culvert. Uncontrolled surface runoffs from the site are presently discharged to Star Top Road s shallow ditch. The absence of a municipal storm sewer is one of the issues to be dealt with since storm water management

5 SWM DESIGN BRIEF OTTAWA REGIONAL ELEVATOR 1519, StarTop Road, Ottawa File number 2013-DRA-804 Reviewed July requires ponding with downstream inlet control device (IDC) with an easement connection to a new storm sewer to be constructed across Star Top Road. 4.3 IDF Curves Runoff and storage volume where computed for 5 and 100 year recurrence storms which were obtained from the Short Duration Rainfall Intensity-Duration-Frequency Data provided by Environment Canada, updated May 17 th, 2011, recorded at Ottawa MacDonald Cartier International Airport station. IDF curves are included in Appendix B. 4.4 Time of concentration Time of concentration for very small watersheds tend to oversize the runoff rate since no practical equation exist for their determination. Experience shows that a 10 minute time of concentration should at least be used. Kirpich 1 equation and nomograph for the 1519 Star Top site would suggest a time of concentration en 1.6 minute for runoff from the most remote point of the watershed with a length of travel to reach the outlet at a distance of 54 meters through 1.2 meter drop. Calculation with a minimum time step of 5 minutes is more readily acceptable while a minimum time of concentration of 10 minutes being more realistic. Time of concentration Height of most remote point above outlet (m): 1.2 Distance from most remote point to outlet (m): 54 Time of concentration for small watershed (Kirpich) (min): 1.8 Time of concentration for 5 min time step calculations (min) : Modified Rational Method for Storage Calculations where performed using the MRM for storage calculations which is mostly suitable for very small watersheds, although in some circumstances, this method could result into undersizing the required storage volume depending upon runoff coefficient which do not account for antecedent moisture conditions and baseflow. The punctuated storage volume was oversized with an adjustment factor based on the P180/Ptd 2. 1 P. Z. Kirpich, Civil Engineering, Bol. 10, No 6, June 1940, p hour storm depth/storm critical duration depth ratio

6 SWM DESIGN BRIEF OTTAWA REGIONAL ELEVATOR 1519, StarTop Road, Ottawa File number 2013-DRA-804 Reviewed July Results calculated with 5 minutes time steps are included into Appendix C. The allowable discharge control system was set to a maximum release rate of 28,7 Lps based on pre-development conditions with a runoff coefficient of 46%, 5 year storm recurrence and a time of concentration of 10 minutes. The required storage volume was computed to 73.4 cubic meters while compared with the MITCI method 3 for storage calculations which concluded to a required storage volume of 82 cubic meters. The available storage volume on site is 105 cubic meters. No storage is anticipated over the parking lot since all drainage will be flowing to the proposed pond area. 4.6 Pre and Post development surface runoff coefficient Tables included into Appendix B contain pre and post development data with corresponding runoff coefficients for the computation of the average runoff coefficients for pre and post development drainage system. There is no significant increase between the pre and post runoff coefficient since the actual site is mostly occupied by equivalent impermeable areas while some areas will be replaced with similar soil coverage. Increase of runoff coefficients from pre and post development situation changes from 0.46 to 0.68 respectively. Computation for an appropriate retention volume is considered as a fair practice in soil conservation and preservation against erosion. 4.7 Sediment control Stormwater Quality Objectives, Stormceptor Details and Computer Output are included into Appendix D. The Stormceptor, model STC300 with a 75 mm diameter inlet pipe, is the selected treatment device with the capacity for trapping fine sands, silt, clay and organic particles for the 1519 Star Top post-development conditions. Simulation results obtained from the Version 1.0 (Build ) software from Imbrium Systems Corporation and Imbrium Systems Inc. Simulation was performed using the IDF history from the Ottawa MacDonald Cartier International Airport station (1967 to 2003). The 2011 and 2003 IDF curves will provide similar runoffs. Model STC300 is of sufficient capacity to remove 80 percent of the average annual total suspended solids (TSS) load without scouring previously captured pollutants, 95 percent of the floatable free oil and sediment from stormwater. The table below contain an example of a Fine Particle Size distribution that is a common PSD used in design of 3 SCS Modified Chicago Design Storm

7 SWM DESIGN BRIEF OTTAWA REGIONAL ELEVATOR 1519, StarTop Road, Ottawa File number 2013-DRA-804 Reviewed July water quality devices to ensure proper design for capturing smaller particles and the high load of associated pollutants. Particle Size Distribution Amount Diameter Specific Gravity 20% 20 micron % 60 micron % 150 micron % 400 micron % 2000 micron 2.65 The first 400 mm of hydrocarbon storage shall be lined with fibreglass to provide a double wall containment of the hydrocarbon materials. Equivalencies shall provide performance data with results similar or better performance. Only separators that have been verified by ETV Canada and the Ontario Ministry of Environment New Environmental Technology Evaluation (NETE) will be accepted 5. CONCLUSION AND RECOMMENDATION It is concluded from this servicing and stormwater management design brief that the proposed project can be totally serviced by the existent municipal services, although, the construction of a new sanitary service is recommended and the construction of a new storm sewer that will run across Star Top Road will be required. Since the actual storm drainage system within Star Top road is actually receiving all surface runoffs from the site in its actual state and that an inlet control device (ICD) installed downward from the stormwater dry pond will limit the increase of the peak runoff flows for the 5 and 100 years storm, there is no need to review the Star Top Road municipal services capacities. Design has been conducted to limit the actual runoff peak flow to the actual 5 year return period peak flow for the post-development site condition. The on-site treatment performance of stormwater runoff with STC-300i in-line Stormceptor will exceed the required water quality control criteria for the site. Since the actual water service is of sufficient capacity to fulfill the daily needs for this new project, no new connection or excavation within Star Top Road will be necessary, although, conduit breakage may occur, then, City of Ottawa by-laws and requirements will need to be respected in such situation. Consideration for the control of pollutant migration during and after construction will be treated as an issue to meet the City of Ottawa and MOE Standards which will minimize impacts on downstream systems.

8 SWM DESIGN BRIEF OTTAWA REGIONAL ELEVATOR 1519, StarTop Road, Ottawa File number 2013-DRA-804 Reviewed July Report by: Sagenex Inc Richard Bélec, p.eng. B.A.Sc. Civil Engineering

9 SWM DESIGN BRIEF OTTAWA REGIONAL ELEVATOR 1519, StarTop Road, Ottawa File number 2013-DRA-804 Reviewed July APPENDIX - A Storm Water Management Study Pre and Post Development Drainage System PLAN SCHEDULE: DETAILS-1/3 PREDEV-2/3 POSTDEV-3/3 IMPORTANT NOTES AND DETAILS STORMCEPTOR STC-300I PRE-DEVELOPMNET DRAINAGE SYSTEM POST DEVELOPMENT DRAINAGE SYSTEM

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13 SWM DESIGN BRIEF OTTAWA REGIONAL ELEVATOR 1519, StarTop Road, Ottawa File number 2013-DRA-804 Reviewed July APPENDIX - B IDF Curves Environment Canada

14 Short Duration Rainfall Intensity Duration Frequency Data Données sur I intensité, la durée et la fréquence des chutes de pluie de courte durée /05/17 OTTAWA MACDONALD CARTIER... ON Intensity(mm/h) / Intensité(mm/h) years / ans Latitude 45 o 19 N Longitude 75 o 40 W Elevation / Altitude 114 m Return Periods/ Périodes de retour Years / ans Minutes Duration/Durée Hours/Heures

15 SWM DESIGN BRIEF OTTAWA REGIONAL ELEVATOR 1519, StarTop Road, Ottawa File number 2013-DRA-804 Reviewed July APPENDIX - C Modified Rational Method for Storage Computations For 5 and 100 Years Short Storms

16 SWMM DESIGN BRIEF ASCENSEUR RÉGIONAL 1519, STAR TOP ROAD FILE NUMBER 2013-DRA-804 APPENDIX -C- PAGE 1 OF 3 Reviewed July, 23, 2013 Time of concentration computation Height of most remote point above outlet (m): 1.2 Kirpich = L 0.77 / S Distance from most remot point to outlet (m): 54 L= m Time of concentration for small watershed (Kirpich) (min): 1.8 S= H/L (m/m) Time of concentration used for computations (min) : 10 Time steps for runoff computations (min) 5 Tc 10 min 5 year i (mm/hre) = Tc 10 min 100 year i (mm/hre) = (hre) Pre and post development runoff coefficient 1519 Star Top total area (sqm): 2230 Pre-development site characteristics Description Area Runoff Coef. Ax C Roof commercial Roof residential Ext. Storage gravel (poor) Ext. parking gravel Lawn Total C avg= 0.46 Q peak = C a CiA for Tc =10 min Q pre-5 (cms) = Q pre-100 (cms) = Post-development site characteristics Description Area Runoff Coef. Ax C Roof commercial existant Roof commercial proposed Ext. Storage gravel Ext. Parking asphalt ans sidewalks Lawn Total C avg= 0.68 Q peak = C a CiA for Tc =10 min Q post-5 (cms) = Q post-100 (cms) =

17 SWMM DESIGN BRIEF ASCENSEUR RÉGIONAL 1519, STAR TOP ROAD FILE NUMBER 2013-DRA-804 APPENDIX -C- PAGE 2 OF 3 Reviewed July, 23, 2013 POST DÉVELOPMENT STORAGE COMPUTATIONS Rainstorm recurrence: 5 year Q = x C a x C x i x A C = 0.68 runoff coefficient A = area (ha) C a = 1.00 for 2 to 10 years reccurence S d = q pi t d - Q a (t d + T c )/2 where: S d = var required retention volume (cm) Q a = admissible release rate (cm/s) (for C=0.48) t d = var rainstorm duration T c = 10 time of concentration (min) Control Table t d i t d i q pi S d (min) (mm/hre) (sec) (m/sec) (cms) (cm) E E Storm duration For P E E E E E E E E E P E POST DÉVELOPMENT STORAGE COMPUTATIONS Rainstorm recurrence: 100 year Q (cm/s)= x C a xc x i x A C = 0.68 runoff coefficient A = area (ha) C a = 1.25 for 100 years reccurence S d = q pi t d - Q inlet (t d + T c )/2 where: S d = var required retention volume (cm) Q inlet = ICD (cm/s) (as per 5 year pre-development) t d = var rainstorm duration T c = 10 time of concentration (min) Control Table t d i t d i q pi S d S d x F c (*) (min) (mm/hre) (sec) (m/sec) (cms) (cm) (cm) E E E E E E Storm duration For P E E E E E For P E n/a (*) See table next page for the storage correction factor

18 SWMM DESIGN BRIEF ASCENSEUR RÉGIONAL 1519, STAR TOP ROAD FILE NUMBER 2013-DRA-804 APPENDIX -C- PAGE 3 OF 3 Reviewed July, 23, 2013 STORAGE VOLUME ADJUSTMENT FOR 100 YEAR STORM Ajustement factor to the calculated storage volume to account for undersizing by using the P 180 /P td factor which is the ratio of the 3-hour storm depth for the return frequency divided by the rainfall depth for the critical storm duration Correction factor F c 100 YEAR P 180 / P 40 = CORRECTED 100 YEAR STORM STORAGE DESIGN VOLUME (cm) = 75 Storage reservoir - Depth to Volume Relationship A inlet (sqm): mm x 84 mm STORAGE HEAD OVER ICD H (m) H (m) Area V partial V cumul Q inlet V cumul Q inlet (mm) (mm) (sqm) (cm) (cm) (cms) (ha-m) (Lps) RUNOFF HYDROGRAPH(*) INLET HYDROGRAPH Qpi (cms) / T (hres) Qinlet (cms) / T (hres) Qpi (cms) / T (hres) 0.01 Qinlet (cms) / T (hres) (*) Continuous routine completed with OTTHYMO. Initial abstraction was 1,5 mm/hre, baseflow was 0 cms Sagenex Inc Richard Bélec, p.eng. B.A.Sc. Civil Engineering

19 SWM DESIGN BRIEF OTTAWA REGIONAL ELEVATOR 1519, StarTop Road, Ottawa File number 2013-DRA-804 Reviewed July APPENDIX - D Stormwater Quality Objectives Stormceptor STC-300i Details and Computer Output

20 Stormceptor Sizing Detailed Report PCSWMM for Stormceptor Project Information Date Project Name Project Number Location Richard Bélec, p.eng DRA , StarTop Road, Ottawa Stormwater Quality Objective This report outlines how Stormceptor System can achieve a defined water quality objective through the removal of total suspended solids (TSS). Attached to this report is the Stormceptor Sizing Summary. Stormceptor System Recommendation The Stormceptor System model STC 300 achieves the water quality objective removing 100% TSS for a Fine (organics, silts and sand) particle size distribution; providing continuous positive treatment for a stormwater quality flow rate of 27.8 L/s. The Stormceptor System The Stormceptor oil and sediment separator is sized to treat stormwater runoff by removing pollutants through gravity separation and flotation. Stormceptor s patented design generates positive TSS removal for all rainfall events, including large storms. Significant levels of pollutants such as heavy metals, free oils and nutrients are prevented from entering natural water resources and the re-suspension of previously captured sediment (scour) does not occur. Stormceptor provides a high level of TSS removal for small frequent storm events that represent the majority of annual rainfall volume and pollutant load. Positive treatment continues for large infrequent events, however, such events have little impact on the average annual TSS removal as they represent a small percentage of the total runoff volume and pollutant load. Stormceptor is the only oil and sediment separator on the market sized to remove TSS for a wide range of particle sizes, including fine sediments (clays and silts), that are often overlooked in the design of other stormwater treatment devices. 1

21 Small storms dominate hydrologic activity, US EPA reports Early efforts in stormwater management focused on flood events ranging from the 2-yr to the 100-yr storm. Increasingly stormwater professionals have come to realize that small storms (i.e. < 1 in. rainfall) dominate watershed hydrologic parameters typically associated with water quality management issues and BMP design. These small storms are responsible for most annual urban runoff and groundwater recharge. Likewise, with the exception of eroded sediment, they are responsible for most pollutant washoff from urban surfaces. Therefore, the small storms are of most concern for the stormwater management objectives of ground water recharge, water quality resource protection and thermal impacts control. Most rainfall events are much smaller than design storms used for urban drainage models. In any given area, most frequently recurrent rainfall events are small (less than 1 in. of daily rainfall). Continuous simulation offers possibilities for designing and managing BMPs on an individual site-by-site basis that are not provided by other widely used simpler analysis methods. Therefore its application and use should be encouraged. US EPA Stormwater Best Management Practice Design Guide, Volume 1 General Considerations, 2004 Design Methodology Each Stormceptor system is sized using PCSWMM for Stormceptor, a continuous simulation model based on US EPA SWMM. The program calculates hydrology from up-to-date local historical rainfall data and specified site parameters. With US EPA SWMM s precision, every Stormceptor unit is designed to achieve a defined water quality objective. The TSS removal data presented follows US EPA guidelines to reduce the average annual TSS load. Stormceptor s unit process for TSS removal is settling. The settling model calculates TSS removal by analyzing (summary of analysis presented in Appendix 2): Site parameters Continuous historical rainfall, including duration, distribution, peaks (Figure 1) Interevent periods Particle size distribution Particle settling velocities (Stokes Law, corrected for drag) TSS load (Figure 2) Detention time of the system The Stormceptor System maintains continuous positive TSS removal for all influent flow rates. Figure 3 illustrates the continuous treatment by Stormceptor throughout the full range of storm events analyzed. It is clear that large events do not significantly impact the average annual TSS removal. There is no decline in cumulative TSS removal, indicating scour does not occur as the flow rate increases. 2

22 Figure 1. Runoff Volume by Flow Rate for OTTAWA MACDONALD-CARTIER INT'L A ON 6000, 1967 to 2003 for 0.22 ha, 0.7% impervious. Small frequent storm events represent the majority of annual rainfall volume. Large infrequent events have little impact on the average annual TSS removal, as they represent a small percentage of the total annual volume of runoff. Figure 2. Long Term Pollutant Load by Flow Rate for OTTAWA MACDONALD-CARTIER INT'L A 6000, 1967 to 2003 for 0.22 ha, 0.7% impervious. The majority of the annual pollutant load is transported by small frequent storm events. Conversely, large infrequent events carry an insignificant percentage of the total annual pollutant load. 3

23 Stormceptor Model TSS Removal (%) STC Drainage Area (ha) Impervious (%) WQ Flow Rate (L/s) Figure 3. Cumulative TSS Removal by Flow Rate for OTTAWA MACDONALD-CARTIER INT'L A 6000, 1967 to Stormceptor continuously removes TSS throughout the full range of storm events analyzed. Note that large events do not significantly impact the average annual TSS removal. Therefore no decline in cumulative TSS removal indicates scour does not occur as the flow rate increases. 4

24 Appendix 1 Stormceptor Design Summary Project Information Date Project Name Richard Bélec, p.eng. Project Number Location Designer Information Company Contact Notes 2013-DRA , StarTop Road, Ottawa Sagenex Inc Post-development conditions Drainage Area Richard Bélec, p.eng. Total Area (ha) 0.22 Imperviousness (%) 0.7 The Stormceptor System model STC 300 achieves the water quality objective removing 100% TSS for a Fine (organics, silts and sand) particle size distribution; providing continuous positive treatment for a stormwater quality flow rate of 27.8 L/s. Rainfall Name State OTTAWA MACDONALD-CARTIER INT'L A ON ID 6000 Years of Records 1967 to 2003 Latitude Longitude 45 19'N 75 40'W Water Quality Objective TSS Removal (%) 80 WQ Flow Rate (L/s) 27.8 Upstream Storage Storage Discharge (ha-m) (L/s) Partial Listing Stormceptor Sizing Summary Stormceptor Model TSS Removal % STC STC STC STC STC STC STC STC STC STC STC STC

25 Particle Size Distribution Removing silt particles from runoff ensures that the majority of the pollutants, such as hydrocarbons and heavy metals that adhere to fine particles, are not discharged into our natural water courses. The table below lists the particle size distribution used to define the annual TSS removal. Fine (organics, silts and sand) Particle Size Distribution Specific Settling Specific Settling Particle Size Distribution Gravity Velocity Gravity Velocity µm % m/s µm % m/s Stormceptor Design Notes Stormceptor performance estimates are based on simulations using PCSWMM for Stormceptor version 1.0 Design estimates listed are only representative of specific project requirements based on total suspended solids (TSS) removal. Only the STC 300 is adaptable to function with a catch basin inlet and/or inline pipes. Only the Stormceptor models STC 750 to STC 6000 may accommodate multiple inlet pipes. Inlet and outlet invert elevation differences are as follows: Inlet and Outlet Pipe Invert Elevations Differences Inlet Pipe Configuration STC 300 STC 750 to STC 9000 to STC 6000 STC Single inlet pipe 75 mm 25 mm 75 mm Multiple inlet pipes 75 mm 75 mm Only one inlet pipe. Design estimates are based on stable site conditions only, after construction is completed. Design estimates assume that the storm drain is not submerged during zero flows. For submerged applications, please contact your local Stormceptor representative. Design estimates may be modified for specific spills controls. Please contact your local Stormceptor representative for further assistance. For pricing inquiries or assistance, please contact Imbrium Systems Inc.,

26 Appendix 2 Summary of Design Assumptions SITE DETAILS Site Drainage Area Total Area (ha) 0.22 Imperviousness (%) 0.7 Surface Characteristics Width (m) 94 Slope (%) 2 Impervious Depression Storage (mm) Pervious Depression Storage (mm) 5.08 Impervious Manning s n Pervious Manning's n 0.25 Maintenance Frequency Sediment build-up reduces the storage volume for sedimentation. Frequency of maintenance is assumed for TSS removal calculations. Maintenance Frequency (months) 12 Infiltration Parameters Horton s equation is used to estimate infiltration Max. Infiltration Rate (mm/h) Min. Infiltration Rate (mm/h) Decay Rate (s -1 ) Regeneration Rate (s -1 ) 0.01 Evaporation Daily Evaporation Rate (mm/day) 2.54 Dry Weather Flow Dry Weather Flow (L/s) No Upstream Attenuation Stage-storage and stage-discharge relationship used to model attenuation upstream of the Stormceptor System is identified in the table below. Storage Discharge ha-m L/s Partial Listing 7

27 PARTICLE SIZE DISTRIBUTION Particle Size Distribution Removing fine particles from runoff ensures the majority of pollutants, such as heavy metals, hydrocarbons, free oils and nutrients are not discharged into natural water resources. The table below identifies the particle size distribution selected to define TSS removal for the design of the Stormceptor System. Fine (organics, silts and sand) Distribution Specific Settling Specific Particle Size Distribution Gravity Velocity Gravity µm % m/s µm % m/s Particle Size Settling Velocity Figure 1. PCSWMM for Stormceptor standard design grain size distributions. 8

28 TSS LOADING TSS Loading Parameters TSS Loading Function Buildup / Washoff Parameters Target Event Mean Concentration (EMC) (mg/l) 125 Exponential Buildup Power 0.4 Exponential Washoff Exponential 0.2 HYDROLOGY ANALYSIS PCSWMM for Stormceptor calculates annual hydrology with the US EPA SWMM and local continuous historical rainfall data. Performance calculations of the Stormceptor System are based on the average annual removal of TSS for the selected site parameters. The Stormceptor System is engineered to capture fine particles (silts and sands) by focusing on average annual runoff volume ensuring positive removal efficiency is maintained during all rainfall events, while preventing the opportunity for negative removal efficiency (scour). Smaller recurring storms account for the majority of rainfall events and average annual runoff volume, as observed in the historical rainfall data analyses presented in this section. Rainfall Station Rainfall Station OTTAWA MACDONALD-CARTIER INT'L A Rainfall File Name ON6000.NDC Total Number of Events 4537 Latitude 45 19'N Total Rainfall (mm) Longitude 75 40'W Average Annual Rainfall (mm) Elevation (m) Total Evaporation (mm) 12.7 Rainfall Period of Record (y) 37 Total Infiltration (mm) Total Rainfall Period (y) 37 Percentage of Rainfall that is Runoff (%) 1.0 9

29 Rainfall Event Analysis Percentage of Percentage of Rainfall Depth No. of Events Total Volume Total Events Annual Volume mm % mm % >

30 Pollutograph Flow Rate Cumulative Mass L/s %

31 Rainfall over study area: OTTAWA MACDONALD-CARTIER INT'L A, ON (ON6000) Modeled years Rainfall (mm) Date/Time

32 Inflow hydrograph to Stormceptor unit: OTTAWA MACDONALD-CARTIER INT'L A, ON (ON6000) Modeled years Flow (L/s) Date/Time

33 Cumulative Volume of Runoff by Runoff Rate For area:.22 (ha), imperviousness:.7%, rainfall station: OTTAWA MACDONALD-CARTIER INT'L A Cumulative Runoff Volume (%) Flow (L/s)

34 SWM DESIGN BRIEF OTTAWA REGIONAL ELEVATOR 1519, StarTop Road, Ottawa File number 2013-DRA-804 Reviewed July APPENDIX - E Survey Plan by Farley, Smith & Denis Surveying Ltd

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