DRAINAGE REPORT. Ministry of Transportation and Infrastructure. Highway 7 Four Laning Silverdale Avenue to Nelson Street 100% Detailed Design

Transcription

1 DRAINAGE REPORT Ministry of Transportation and Infrastructure Highway 7 Four Laning Silverdale Avenue to Nelson Street 100% Detailed Design December 14, 2017 Reviewed by: Amanda Rust, P. Eng. Senior Drainage Engineer Prepared by: Jennifer Paverd, EIT Drainage Engineer

2 MINISTRY OF TRANSPORTATION AND INFRASTRUCTURE DRAINAGE REPORT HIGHWAY 7 FOUR LANING SILVERDALE AVENUE TO NELSON STREET TABLE OF CONTENTS 1 INTRODUCTION EXISTING DRAINAGE AND SITE CHARACTERISTICS Drainage Catchment Area Existing Highway Ditches and Culvert Network Chester Creek Pump Station BACKGROUND STUDIES Environmental Considerations Fraser River Outfall Conditions DESIGN CRITERIA Design References Design Return Period Culvert Design Life Climate HYDROLOGIC AND HYDRAULIC DRAINAGE MODEL Drainage Model Inputs Drainage Scenarios Modelling Results DRAINAGE DESIGN Culvert Design Catch Basins and Spillways Driveway Culverts CONCLUSIONS AND RECOMMENDATIONS CLOSING TABLES Table 4-1: Precipitation Amounts for Design Return Periods... 9 Table 5-1: Curve Numbers and Soil Groups Table 5-2: Comparison of Q100 Design Flow and Culvert Capacity for Options Table 6-1: Comparison of 200-year daily flows with 100-year instantaneous flows i

3 MINISTRY OF TRANSPORTATION AND INFRASTRUCTURE DRAINAGE REPORT HIGHWAY 7 FOUR LANING SILVERDALE AVENUE TO NELSON STREET FIGURES Figure 1-1: Project Location Source: Google Maps... 1 REFERENCES Golder Associates. (2017). Hydraulic Impact Assessment Technical Memorandum. Binnie. (2013). Highway 7 Silverdale to Chester Creek Drainage Review Draft Memorandum. Hirod Gill, District of Mission. (2012). Summary of available Chester Creek Pump Station Information Memorandum. ENKON. (2013). 50% Detailed Design Environmental Impact Assessment and Preliminary Compensation Requirements. Golder Associates. (2017). Highway 7 widening Project: Silverdale Avenue to Nelson Street, Mission, BC Environmental Impact Assessment. ISL Engineering and Land Services. 100% Preliminary Design Report. District of Mission. (2012). Fraser River Flood Preparedness and Responses Plan. Transportation Association of Canada. (2001). Guide to Bridge Hydraulics Second Edition. Urban Systems. (2008)/ Silverdale Urban Residential Area Neighbourhood One Final Report. Government of Canada. Canadian Climate Normals Precipitation Data. (Accessed on: July 14, 2017) Retrieved from: Northwest Hydraulic Consultants. (2008). BC Ministry of Environment, Fraser River Hydraulic model update final report. Ministry of Forests, Lands and Natural Resource Operations. Freshet Information. (Accessed on: July 24, 2017). Retrieved from: Western University. Mission West Abbey IDF curves. (Accessed on: June 29, 2017). Retrieved from: APPENDICES Appendix A: Appendix B: Appendix C: Appendix D: Appendix E: Appendix F: Catchment Areas District of Mission IDF Curve Model Inputs Model Results Review of Q200 Design Flows Average Two-Year Design Velocities ii

4 MINISTRY OF TRANSPORTATION AND INFRASTRUCTURE DRAINAGE REPORT HIGHWAY 7 FOUR LANING SILVERDALE AVENUE TO NELSON STREET 1 INTRODUCTION R.F. Binnie & Associates Ltd. (Binnie) was requested by Ministry of Transportation and Infrastructure (MoTI) to carry out a 100% detailed design for widening a 3.13-km section of Highway 7 from Silverdale Avenue (Sta ) to Nelson Street (Sta ) to four lanes. The project includes drainage design to upgrade the culverts crossing the highway to handle the peak flow for a Q100 event. The extent of the project is from Silverdale Avenue to Nelson Street as shown in Figure 1-1 below. N Project Area Figure 1-1: Project Location - Source: Google Maps The purpose of this report is to review the existing drainage patterns, determine catchment areas, calculate design flows, and document the detailed drainage design for the highway upgrade. The drainage design conforms to the BC Supplement to TAC Geometric Design Guide Section

5 MINISTRY OF TRANSPORTATION AND INFRASTRUCTURE DRAINAGE REPORT HIGHWAY 7 FOUR LANING SILVERDALE AVENUE TO NELSON STREET 2 EXISTING DRAINAGE AND SITE CHARACTERISTICS 2.1 Drainage Catchment Area The project is located within an area of Highway 7 with primarily forested land in the upper reaches of the catchment transitioning to open pasture and grasslands towards the Fraser River. Drainage basins for the catchment were identified using the District of Mission GIS, a contour map generated by LiDAR survey (provided by McElhanney), and available ground survey data adjacent to the highway (provided by Binnie). The drainage areas are shown in Appendix A, Figure 1. The typical drainage pattern for the total watershed area is from north to south, from a maximum elevation of 330 m to low lying ground discharging into the Fraser River. The Chester Creek drainage area (Catchment A) drains along the existing highway alignment toward the west, to an existing pump station with a total catchment area of 504 ha. There is an additional 136 ha (Catchment C) that drains into the Fraser River near Silverdale Avenue. Catchment B (63 ha) lies between these catchments and discharges into the bottom reach of Chester Creek via culverts at Sta and Sta before flowing towards the Fraser River. The south drainage boundary is marked by the existing Canadian Pacific Railway located to the south of Highway 7. The railway acts as a dike for the drainage. There is agricultural land south of the railway track that is protected from the Fraser River water levels by the Silverdale Dike. The Chester Creek drainage area naturally discharges into the Fraser River, except when the gates at the Chester Creek Pump Station are manually closed by the District of Mission, and the pump is operational. Typically, this occurs during spring freshet (May to July) or other Fraser River high water events. The pump operating levels are between elevations of 3.2 m to 3.5 m, with a maximum discharge of 1m 3 /s (Golder, 2017). 2.2 Existing Highway Ditches and Culvert Network Chester Creek converges into the northern highway ditch/creek at Sta and runs toward the west, collecting runoff and flow from several small tributaries. A backwater channel runs from Sta to Nelson Street along the northern boundary of the highway. The existing 450mm diameter culvert at Sta conveys flows from catchment A0 towards the backwater channel along the northern boundary of Highway 7. It is proposed to upgrade this culvert to a 750mm diameter pipe. At Sta an existing pipe arch farm access underpass runs beneath Highway 7. This acts as an overland flow path during peak flow events. It conveys excess flow into the southern highway ditch (Sta ), which also flows towards the west. It is proposed to replace this farm access underpass with a 1500-mm diameter culvert. There is an additional farm access underpass under the railway at approximately Sta which will convey peak flows towards the south. This overland flow path directs flows to the agricultural land located immediately south of the railway. 4

6 MINISTRY OF TRANSPORTATION AND INFRASTRUCTURE DRAINAGE REPORT HIGHWAY 7 FOUR LANING SILVERDALE AVENUE TO NELSON STREET The main Chester Creek channel flows west past the farm access underpasses along the northern edge of the highway. An existing 1500mm diameter pipe is located beneath Chester Street to convey flows in the northern highway ditch/ creek (catchments A0 to A1-8) towards the west. Approximately 420 m west of Chester Street (Sta ), an existing 1500-mm diameter cross culvert conveys Chester Creek and an additional tributary (catchments A0 to A1-9) across the highway to the southern highway ditch/creek. From there, it continues to flow toward the pump station located at Sta It is proposed that the existing culvert is upgraded to a 2400-mm diameter steel pipe, utilizing trenchless technology. Discharge from catchment A1-10 flows through an existing cross culvert at Sta (470-mm diameter). It is proposed to upgrade this to a 1200 mm cross culvert at Sta , utilizing trenchless technology. To the west of the pump station all runoff from Catchment B is conveyed along the north and south ditches/creek and across the highway at existing culverts (Sta mm diameter, Sta mm diameter and Sta mm diameter) into Chester Creek downstream of the pump station. It is proposed to replace these culverts with a 900-mm diameter culvert at Sta , a 900-mm diameter culvert at Sta and a 750-mm diameter culvert at Sta It is also proposed to have an additional 600-mm diameter cross culvert at Sta Runoff from Catchment C flows via an unnamed stream into the northern highway ditch before crossing the highway in an existing 900 mm culvert at Sta and an existing 900 mm culvert at Sta From here the two culverts discharge into Jameson Creek and flow toward the west before discharging into the Fraser River. No work is proposed for these culverts as part of this project. The drainage channels along the highway, both north and south are very flat with localized low spots with ponding and wetland areas. One larger wetland area is in the southern highway ditch starting near the farm underpass at Sta and ending at Sta Chester Creek Pump Station A summary report provided by Hirod Gill in 2012 outlines the available information on the Chester Creek pump station. The pump station is located adjacent to the highway at approximately Sta and has a current pumping capacity of 1.0m 3 /s which is supplemented by a 2m 2 flood gate. The pump station provides flood protection to approximately 60 ha of agricultural land upstream. The pump station flood gate is manually operated during freshet events and other high flow events in the Fraser River. It is generally operated in May and June. The District of Mission Public Works department confirmed that the gate is closed only during freshet in the Fraser River. The pump operates automatically during high flow events, turning on once the water level elevations reaches 3.5 m and turning off once the water elevation drops to 3.2 m. At the time of writing this report, it is understood that the District of Mission is in the process of commissioning an upgrade of the Chester Creek pump station. The timing of the upgrade work is currently unknown due to the potential future development of land in the upper catchments of Chester Creek. For this design and report it has been assumed that the pump station has not been upgraded, 5

7 MINISTRY OF TRANSPORTATION AND INFRASTRUCTURE DRAINAGE REPORT HIGHWAY 7 FOUR LANING SILVERDALE AVENUE TO NELSON STREET and no development of the land has been undertaken. It is recommended that the pump station be upgraded prior to future development to limit the potential of damage to upstream properties caused by flooding. In addition to upgrading the pump station, it is recommended that the operating periods and levels are reviewed to provide adequate drainage for Chester Creek and the adjacent highway ditches during large rainfall events. Sedimentation problems are known to occur along Chester Creek, with sediment and gravel accumulating at the pump station intake as well as downstream of the pump station. Ongoing maintenance work will likely be required along the highway ditches and around the pump station intake to ensure that the channels can convey the full design flow and allow the pump station to operate to its full capacity. No further work has been done regarding the Chester Creek pump station for this report and drainage design. 6

8 MINISTRY OF TRANSPORTATION AND INFRASTRUCTURE DRAINAGE REPORT HIGHWAY 7 FOUR LANING SILVERDALE AVENUE TO NELSON STREET 3 BACKGROUND STUDIES 3.1 Environmental Considerations Environmental assessments were done previously by ENKON Environmental Ltd. (ENKON) in 2013, with a recent update in 2017 by Golder Associates Ltd. (Golder). Both reports note that fish access is impeded by the closure of the pump station flood gate. Proposed modifications to Chester Creek and the highway ditches are within a riparian and in-stream fish habitat. The Golder report highlights mitigation measures for the proposed design. 3.2 Fraser River Outfall Conditions The BC Ministry of Environment Fraser River Hydraulic Model Update Final Report by Northwest Hydraulic Consultants in March 2008, has calculated the 200-year Fraser River elevation to be 8.48 m at Silverdale Creek. The Mission flood plan mapping (2007) includes a 0.6 m freeboard which increases flood protection level to 9.5 m for the 200-year event. Historic events suggest a maximum water level of 7.6 m above sea level at the Mission station. Peak water levels in the Fraser River are associated with spring freshet. The Chester Creek pump station is operated during the Fraser River freshet and restricts the outfall flow to the Fraser River. The Fraser River water level in Mission is typically lower in the fall and winter months, so the flood gate is left open. The drainage design model analysis has assessed the hydraulic conditions of the culverts during a Q100 event under free outfall conditions with both the pump station gate open as well as the surcharge hydraulic conditions in the ditch/channel during operation of the Chester Creek pump station. It was assumed that free normal conditions correlate to an outfall water elevation of 3.2 m. This outfall elevation has been based on an Urban Systems report highlighting a gravel deposit build up downstream of the pump station creating a surcharge depth 0.8 m above the base of the flood gate invert at 2.4 m elevation. 7

9 MINISTRY OF TRANSPORTATION AND INFRASTRUCTURE DRAINAGE REPORT HIGHWAY 7 FOUR LANING SILVERDALE AVENUE TO NELSON STREET 4 DESIGN CRITERIA 4.1 Design References The following regulations were used to develop design criteria for the project: Ministry of Transportation and Infrastructure Supplement to TAC Geometric Design Guide Water Sustainability Act (WSA) Ministry of Transportation and Infrastructure Technical Circular T15-06 Climate Change and Extreme Weather Event Preparedness and Resilience in Engineering Infrastructure Design District of Mission Development and Subdivision Control Bylaw The following guidance documents were also referenced to develop the drainage design: TAC Guide to Bridge Hydraulics Second Edition Guidelines Department of Fisheries and Oceans Land Development Guidelines Section 6 Fish Passage and Culverts 4.2 Design Return Period The culverts have been designed to pass the peak instantaneous design flows for the 100-year rainfall event, as per TAC Table 1010.A for culverts with a span under 3m within arterial roads and freeways. The culverts have also been assessed as per the WSA regulations. The culvert capacity is to be designed to the equivalent of the hydraulic capacity of the stream channel, or capable of passing the one in 200- year maximum daily flow without the water level at the culvert inlet exceeding the top of the culvert. In addition, the proposed culverts have also been designed as per the Land Development Guidelines for Fish Passage for Adult Fish. It requires fish bearing culverts to be sized to ensure the maximum guidance velocities are not exceeded for more than three consecutive days in an average year. 4.3 Culvert Design Life The project is located within a stretch of Highway 7 that sees high traffic volumes and therefore the culverts within the project are to be designed for a design life of 75 years. Existing water quality data from the site has been used to confirm corrugated steel pipe (CSP) culvert durability with aluminized coating or increased wall thicknesses are suitable for a design life of 75 years. Alternative culvert materials such as high-density polyethylene (HPDE) are also suitable for a design life of 75 years. 4.4 Climate A review of the average monthly rainfall data from the Canadian Climate Normals Station Data suggest maximum precipitation events typically occur during the fall and winter months of October to January. For the drainage design two scenarios have been assessed; the Q100 peak rainfall occurring outside of freshet and the Q100 peak rainfall occurring during freshet. The rainfall data used for this project is from the Mission West Abbey Station, ID: as analyzed by the District of Mission (attached in Appendix B). 8

10 MINISTRY OF TRANSPORTATION AND INFRASTRUCTURE DRAINAGE REPORT HIGHWAY 7 FOUR LANING SILVERDALE AVENUE TO NELSON STREET Climate Change Assessment The technical circular release by MoTI on June 22, 2015 details climate change and extreme weather preparedness. The document states that all MoTI projects must consider climate change when considering weather projections. Climate change projections have been assessed through to To determine the projected climate change for the project, the District of Mission IDF Curve has been assessed in conjunction with climate change. A predicted increase in rainfall for the 100-year, 24-hour storm event is from mm to mm, which is equivalent to a 24% increase in rainfall as determined by comparing with a Representative Concentration Pathway (RCP) 8.5 assessment using the IDF tools. RCP 8.5 is the worst-case scenario used for climate change assessment in BC. For the proposed design it has been assumed that majority of the culverts will need to be upsized to allow for increased runoff from climate change. All design flows were determined based on an average 24% increase in rainfall patterns to account for climate change Design Precipitation Climate change projections are included in the rainfall data projections. The design flows including climate change are shown below in Table 4-1. Table 4-1: Total Precipitation Amounts for Design Return Periods Including Climate Change Return Period Rainfall Duration 2-year 100-year 200-year 5 min 4.84 mm 9.92 mm mm 1 hour mm mm mm 24 hours mm mm mm 9

11 MINISTRY OF TRANSPORTATION AND INFRASTRUCTURE DRAINAGE REPORT HIGHWAY 7 FOUR LANING SILVERDALE AVENUE TO NELSON STREET 5 HYDROLOGIC AND HYDRAULIC DRAINAGE MODEL The hydrology and highway culvert hydraulics were calculated using the Autodesk Storm and Sanitary Analysis 2012 (SSA) tool, which follows the SCS TR-55 analysis for storage and hydrodynamic flow to model backflow conditions. Detailed SSA model input and results are included in Appendices C and D. 5.1 Drainage Model Inputs Below is a summary of model assumptions and input data for the proposed design including climate change: The SCS TR-55 method will be used to calculate peak runoff. A manning s roughness coefficient of 0.05 has been assumed for all open channels. A manning s roughness coefficient of has been assumed for all HDPE and steel pipes and assumed for all CSP pipes. Entrance and exit losses of have been assumed for all culverts based on the inlet and outlet structures. Rainfall intensity will be obtained from the Mission West Abbey (1963 to 2010) IDF Curve, as prepared by the District of Mission. The intensity includes a 24% climate change factor as predicted to 2100 for the design event. The SCS TR-55 method was used to determine the time of concentration. The hydraulic analysis has allowed overflow at high water events to flow through the farm underpasses, and outfall south of the railway, as per existing drainage conditions. The pump station was set to operate from an initial water level elevation of 3.5 m, until the water level drops to 3.2 m depth, with a maximum capacity of 1m 3 /s. Available ponding has been allowed at each node in the model to represent the flow remaining in the system and draining when there is available space in the system. All culvert lengths and locations are based on the proposed new locations. For the purpose of analyzing the major event, Q100, it is assumed there is little retentive benefit from the low ponding wetland areas in the north and south highway ditches, as they are assumed to already be filled with water during the Q100 event. All new culverts 900 mm and less are assumed to be HDPE. The culverts at Sta and Sta are steel pipes. The L300 cross culvert and the culvert at Sta are to be CSP. All new culverts less than 900-mm diameter are designed with no headwalls. Existing box or arch culverts have been modelled as such. The ditch/channel conduits were generally assumed to be trapezoidal, with the width and bottom of channel based on the average design widths and depths. Any narrow and deeper sections of the channel which are lower than the average ditch depths have not been included in the design model. 10

12 MINISTRY OF TRANSPORTATION AND INFRASTRUCTURE DRAINAGE REPORT HIGHWAY 7 FOUR LANING SILVERDALE AVENUE TO NELSON STREET The elevation inverts on the base model are based on the available survey information at the time of this report. Where survey data was unavailable, the channel dimensions were assumed based on LiDAR. Proposed culvert along the L700 line has not been included in the model as only a small proportion of flow from Catchment A0 will pass through the flow. The design flow has been calculated using the SCS TR55 method in a separate calculation. Curve numbers vary depending on the soil groups and the ground coverage. A review of the available aerial images has been used to assess the curve numbers. Refer to Table 5-1 below for a summary of the factors. Table 5-1: Curve Numbers and Soil Groups Land Coverage Soil Group CN Number Good wood coverage B 55 Good wood coverage B/C 63 Good wood coverage C n/a Good pasture or grassland B 61 Good pasture or grassland C 74 Fair pasture or grassland C 79 Fair pasture or grassland C/D 82 >75% grass cover, golf course B 61 2-acre lots, 12% impervious B 65 2-acre lots, 12% impervious C 77 1-acre lots, 20% impervious B 68 ¼ acre lots, 38% impervious B 75 Paved parking and roofs C Drainage Scenarios Two variations of the model have been run. The culvert sizes in the models have been designed to facilitate the hydraulics and maintain a maximum/total depth ratio less than one, where possible (i.e. water level less than the height of the culvert). A summary of the scenarios is outlined below: Scenario 1: Base model with climate change, assuming the pump station is under operating conditions, with a maximum capacity of 1 m 3. Scenario 2: The Chester Creek pump station gate is fully open allowing discharge into the Fraser River, via a 2 m 2 flood gate. Note: The water level elevation in the Fraser River Outfall is set to 3.2 m for all the above design events. The model used hydrodynamic flow routing, which allows for backwater and storage. During peak flow events the pump house located near the outlet of Chester Creek to the Fraser River restricts flow and causes water to back up through the highway ditches and culverts. The maximum HW/D at some of the 11

13 MINISTRY OF TRANSPORTATION AND INFRASTRUCTURE DRAINAGE REPORT HIGHWAY 7 FOUR LANING SILVERDALE AVENUE TO NELSON STREET culverts is a function of result of this backwater as opposed to the peak runoff flow from the associated catchment area. All peak flow results are based on this rainfall data with a 24% increase to account for climate change, and are based on assumptions and model rationale identified above, along with their implied published limitations. 5.3 Modeling Results The proposed culverts have been designed to pass the peak instantaneous design flows for the 100- year rainfall event with a HW/D less than one. As seen in the table below, the Chester Street culvert does not meet this criterion, however upgrading this culvert is outside the scope of work for this project and therefore the culvert has not been resized. The culvert design information is summarized in Table 5-2 below, for the Q100 design event. The model results are included in Appendix D. Table 5-2: Comparison of Q100 Design Flow and Culvert Capacity for Scenarios 1 and 2 Option 1 Option 2 Pipe Q100 Capacity HW/ Pipe Q100 Capacity HW/ Culvert ID Dia (m) (m 3 /s) (m 3 /s) D Dia (m) (m 3 /s) (m 3 /s) D Chester Street Culvert Cross Sta Cross Cross Cross Cross > Cross Culvert Sta to Sta FarmUnderPass@Sta Pr. Sta Pr. Sta Pump Station Gate n/a n/a n/a n/a 1x Cross L700 Sta The results indicate that the major difference between scenarios 1 and 2 is the depth of water throughout the channels and culverts. During scenario 2, only the L300 culvert is surcharged and the flow through the railway underpass is significantly reduced from 3.8m 3 /s to 0.6m 3 /s. Scenario 1 has been run with an increased pump capacity to reduce the culvert surcharging in all culverts except for the L300 culvert. To meet this requirement the pump station capacity would need to be increased to at least 4 m 3 /s. 12

14 MINISTRY OF TRANSPORTATION AND INFRASTRUCTURE DRAINAGE REPORT HIGHWAY 7 FOUR LANING SILVERDALE AVENUE TO NELSON STREET The agricultural land located to the north of the highway is located significantly lower than the CPR Rail line and the highway, with the majority of the land located between elevations of 4-5 m with some areas lower than 4 m in elevation. In the worst-case scenario (scenario 1) there is potential flooding along the northern channel from approximately Sta to Sta It is likely that the flooding depth could be decreased by removing/replacing the existing Chester Street culvert, implementing a storage pond with an increased invert depth at the existing Chester Street and Highway 7 intersection and increasing the capacity of the Chester Creek pump. 13

15 MINISTRY OF TRANSPORTATION AND INFRASTRUCTURE DRAINAGE REPORT HIGHWAY 7 FOUR LANING SILVERDALE AVENUE TO NELSON STREET 6 DRAINAGE DESIGN 6.1 Culvert Design The proposed culverts at Sta and Sta do not meet the HW/D less than one criteria during a 100-year rainfall intensity when the flood gate is closed, but do meet the criteria when the flood gate is open. The capacity of these pipes can pass the 200-year daily flow from the upstream channel without the water level at the culvert inlet exceeding the top of the culvert or over topping the road when the flood gate is closed as per the WSA. Based on this, it is considered a suitable size with the limiting factor within the overall network being the capacity of the pump as well as the elevations of the surrounding land north of the upstream channel. The proposed culvert at Sta does not meet the HW/D criteria during scenarios 1 and 2. However, it can pass the 200-year daily flows. This culvert does not convey large flows from upstream but rather enables the culvert and ditches to act as a storage system to contain the flow that ponds because of the pump station operation Culvert Fish Passage Design The roadside ditches and channels along the project are considered to be fish bearing, and have been designed to the Water Sustainability Regulations. Under the WSA Regulations, the culvert capacity is to be designed to the equivalent of the hydraulic capacity of the stream channel, or is to be capable of passing the one in 200-year maximum daily flow without the water level at the culvert inlet exceeding the top of the culvert. The model was run using the 200-year rainfall intensity of mm with a SCS Type 1A-24hour storm distribution. A peaking ration of two (based on the TAC Guide to Bridge Hydraulics Second Edition Guidelines) was used to estimate maximum daily flows from the modelled peak flows. Table 6-1 below, indicates that the maximum daily flow for the 200-year event is less than the 100-year peak instantaneous design flows for which the culverts have been designed. Therefore, the culverts are deemed to be adequately sized. Appendix D shows that the culverts that do not meet the HW/D less than one criteria for the 100- year event can pass the maximum daily flow for the 200-year event without surcharge. 14

16 MINISTRY OF TRANSPORTATION AND INFRASTRUCTURE DRAINAGE REPORT HIGHWAY 7 FOUR LANING SILVERDALE AVENUE TO NELSON STREET Table 6-1: Comparison of 200-year Daily Flows with 100-year Instantaneous Flows Option 1 Option 2 Q100 Q200 Q100 Q200 Culvert ID (m 3 /s) (m 3 /s) (m 3 /s) (m 3 /s) Chester Street culvert Cross Sta Cross Cross Cross Cross Cross Culvert Sta to Sta FarmUnderPass@Sta Pr Pr. Sta Pump station gate n/a n/a Cross L700 Sta Land Development Guidelines for Fish Passage for Adult Fish was consulted for additional fish passage design guidelines. The guidelines state that the velocity through fish bearing culverts cannot exceed 1.2 m/s for culverts less than 24.4 m and 0.9m/s for culverts greater than 24.4 m in length for more than three consecutive days in an average year. To check that these criteria are met, the model was analyzed for a two-year rainfall event. The average velocity over a three-day period was then assessed. Appendix E shows the average velocities for each of the culverts during scenario 1. The guidelines also recommend maximum lengths for fish passage culverts. The proposed culvert crossing the L300 line (Sta ) exceeds the recommended maximum culvert length for fish passage due to construction access constraints alongside the Canadian Pacific Railway corridor. It is expected that this culvert will be subject to approval by the Department of Fisheries and Oceans, and the Ministry of Forests, Lands and Natural Resource Operations as part of the overall project review. The large fish bearing culverts at Sta and Sta have been designed with slopes less than 1% to prevent large velocities through the culverts and to allow sedimentation build up along the base of the culverts with time. 15

17 MINISTRY OF TRANSPORTATION AND INFRASTRUCTURE DRAINAGE REPORT HIGHWAY 7 FOUR LANING SILVERDALE AVENUE TO NELSON STREET 6.2 Catch Basins and Spillways The project requires spillways and/or catch basins to manage pavement drainage for the project. The location and quantity of spillways/catch basins was determined in accordance with the BC MoTI Supplement to TAC. From Sta onwards, slotted concrete barriers have been installed to manage pavement drainage. However, due to the flat grade within this area of the project it is recommended that larger barrier openings are utilized every 50 m to allow for extra drainage capabilities if the slotted barriers become blocked. 6.3 Driveway Culverts The project requires one additional culvert to convey runoff under the L500 driveway located to the north of the project. This driveway culvert is designed to convey the peak 25-year return flow while maintaining a maximum HW/D of

18 MINISTRY OF TRANSPORTATION AND INFRASTRUCTURE DRAINAGE REPORT HIGHWAY 7 FOUR LANING SILVERDALE AVENUE TO NELSON STREET 7 CONCLUSIONS AND RECOMMENDATIONS Binnie is providing the Ministry of Transportation and Infrastructure with a 100% detail design for widening a 3.13 km section of Highway from Silverdale Avenue to Nelson into four lanes. This includes drainage design to upgrade the culverts crossing the highway. The report assumes that all Q100 peak flows are conveyed in the upstream catchment area without impediment, and therefore a hydraulic assessment of the upstream pipes, culverts, ditches, or creek channels has not been carried out. It is assumed that if the catchment lands are developed they will limit the runoff to pre-development levels for the peak Q100. The peak Q100 runoff values in this report assume an increase in rainfall due to climate change. This report is for the hydrology calculations and the hydraulic conditions of the culverts crossing the highway during Q100 events, for two different scenarios: (1) pump station operating at maximum capacity, (2) the gates open at the pump station allowing free outfall conditions to the Fraser River. The existing pump station restricts the drainage through Chester Creek causing back water effects and surcharging of the culverts and ditches upstream, and flooding of the adjacent agricultural land. For any future development in the area Binnie recommends that: The pump station capacity is upgraded to minimize backwater flooding effects and associated flooding of adjacent agricultural land. If the Chester Street culvert is to be removed, it should be replaced with suitable storage retention for high flow events, and to increase available riparian zones around the project. Maintenance work is routinely carried out along the channels and around the pump station intake to ensure that the existing pump can operate to its full capacity. 17

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20 APPENDIX A CATCHMENT AREAS

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22 APPENDIX B DISTRICT OF MISSION IDF CURVE

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24 APPENDIX C MODEL INPUTS

25 Autodesk Storm and Sanitary Analysis Version (Build 1) ******************* Project Description ******************* File Name Option 1 _ Pump Station Operating _FINAL.SPF Description... P:\2016\ \05 - Design\Drainage\Drainage Study\ Design Base (for drainage figures).dwg **************** Analysis Options **************** Flow Units... cms Subbasin Hydrograph Method. SCS TR-55 Time of Concentration... SCS TR-55 Link Routing Method... Hydrodynamic Storage Node Exfiltration.. None Starting Date... AUG :00:00 Ending Date... AUG :00:00 Report Time Step... 00:05:00 ************* Element Count ************* Number of rain gages... 1 Number of subbasins Number of nodes Number of links **************** Subbasin Summary **************** Subbasin Total Area ID hectares {Ditch}.A {Ditch}.A {Ditch}.A1-10a 1.01

26 {Ditch}.A {Ditch}.A {Ditch}.A {Ditch}.A {Ditch}.A {Ditch}.A {Ditch}.A1-7a 3.02 {Ditch}.A {Ditch}.A1-8a 1.71 {Ditch}.A {Ditch}.A1-9a 1.08 {Ditch}.A {Ditch}.B {Ditch}.B1-1a 0.63 {Ditch}.B {Ditch}.B1-2b 1.11 {Ditch}.B {Ditch}.B1-3a 0.30 {Ditch}.B {Ditch}.B {Ditch}.C {Ditch}.Ca 0.39 A Sub ************ Node Summary ************ Node Element Invert Maximum Ponded External ID Type Elevation Elev. Area Inflow m m m² JUNCTION JUNCTION JUNCTION JUNCTION JUNCTION JUNCTION JUNCTION JUNCTION JUNCTION JUNCTION JUNCTION

27 12 JUNCTION JUNCTION JUNCTION JUNCTION JUNCTION JUNCTION JUNCTION JUNCTION JUNCTION JUNCTION JUNCTION a JUNCTION JUNCTION JUNCTION JUNCTION JUNCTION a JUNCTION Jun-57 JUNCTION Jun-60 JUNCTION Jun-61 JUNCTION Sta JUNCTION Sta JUNCTION Sta North JUNCTION Sta JUNCTION Sta JUNCTION Sta JUNCTION Sta JUNCTION Sta JUNCTION Sta JUNCTION Sta North JUNCTION Sta JUNCTION Sta North JUNCTION Sta JUNCTION Sta JUNCTION Sta JUNCTION Sta North JUNCTION FarmUnderpassOutfallOUTFALL OutfallSTA107 OUTFALL Out-Sta101 OUTFALL PumpStationOutfall OUTFALL ************ Link Summary

28 ************ Link From Node To Node Element Length Slope Manning's ID Type m % Roughness Chester Creek Tributary34 33 CHANNEL Chester Creek US of Highway32 Sta CHANNEL Chester Street CulvertSta Sta CONDUIT Cross Sta CONDUIT Cross Sta CONDUIT Cross 4 CONDUIT Cross 14 CONDUIT Cross 17 CONDUIT Cross 19 CONDUIT Cross Sta CONDUIT Cross Sta CONDUIT Culvert across Mclean Street6a Out-Sta101 CONDUIT Culvert from Sta to Sta CONDUIT Ex. Underpass_Bridge Sta 124Sta North Sta North CHANNEL Farm underpass to south ditch35 Sta CHANNEL FarmCrossingUnderPass@Sta a 35 CONDUIT L200 to Sta CHANNEL L300 line to Sta 124 (south)sta Sta CHANNEL Link-66 Jun-60 PumpStationOutfallCHANNEL Link-68 Jun-61 FarmUnderpassOutfallCONDUIT Link-69 Sta Sta North CHANNEL Link-70 Sta Sta CHANNEL Link-71 Sta Sta CHANNEL Overflow to farm underpass30a Sta North CHANNEL Pr. L CONDUIT Sta CONDUIT Pump Station to Fraser River20 Jun-60 CHANNEL Pump Station to Sta (south)Sta Sta CHANNEL Railway_underpassJun-61 Sta CONDUIT Sta to Mclean Street6 6a CHANNEL Sta to Sta DIRECT Sta 107 to Sta 107 outfall15 OutfallSTA107 CHANNEL Sta to Sta CHANNEL Sta 10740to Sta CHANNEL Sta to Sta CHANNEL Sta to DS pump station19 20 CHANNEL Sta to Tributaries21 22 CHANNEL Sta 114 to L300 line (south)sta Sta CHANNEL

29 Sta to Chester StreetSta Sta North CHANNEL Sta 119 to Chester StreetSta Sta CHANNEL Sta 119 to Sta 124Sta Sta North CHANNEL Sta 124 (South) Sta Sta CHANNEL Sta 124 (south) Overflow pondjun-57 Sta CHANNEL Sta to Sta127+80Sta Sta North CHANNEL Sta100+90toSta CHANNEL Sta101+35toSta CHANNEL Sta to Sta CHANNEL Sta to L CHANNEL Start of Chester Creek33 32 CHANNEL Pump-02 Sta TYPE4 PUMP ********************* Cross Section Summary ********************* Link Shape Depth/ Width No. of Cross Full Flow Design ID Diameter Barrels Sectional Hydraulic Flow Area Radius Capacity m m m² m cms Chester Creek Tributary TRAPEZOIDAL Chester Creek US of Highway TRAPEZOIDAL Chester Street Culvert CIRCULAR Cross Sta CIRCULAR Cross Sta CIRCULAR Cross CIRCULAR Cross CIRCULAR Cross CIRCULAR Cross CIRCULAR Cross CIRCULAR Cross CIRCULAR Culvert across Mclean Street CIRCULAR Culvert from Sta to Sta CIRCULAR Ex. Underpass_Bridge Sta 124 RECT_OPEN Farm underpass to south ditch TRAPEZOIDAL FarmCrossingUnderPass@Sta CIRCULAR L200 to Sta 107 TRAPEZOIDAL L300 line to Sta 124 (south) TRAPEZOIDAL Link-66 RECT_OPEN Link-68 HORIZ_ELLIPSE

30 Link-69 TRAPEZOIDAL Link-70 TRAPEZOIDAL Link-71 TRAPEZOIDAL Overflow to farm underpass TRAPEZOIDAL Pr. L200 CIRCULAR CIRCULAR Pump Station to Fraser River RECT_OPEN Pump Station to Sta (south) TRAPEZOIDAL Railway_underpass HORIZ_ELLIPSE Sta to Mclean Street TRAPEZOIDAL Sta to Sta DUMMY Sta 107 to Sta 107 outfall TRAPEZOIDAL Sta to Sta TRAPEZOIDAL Sta 10740to Sta 107 TRAPEZOIDAL Sta to Sta 107 TRAPEZOIDAL Sta to DS pump station TRAPEZOIDAL Sta to Tributaries TRAPEZOIDAL Sta 114 to L300 line (south) TRAPEZOIDAL Sta to Chester Street TRAPEZOIDAL Sta 119 to Chester Street TRAPEZOIDAL Sta 119 to Sta 124 TRAPEZOIDAL Sta 124 (South) RECT_OPEN Sta 124 (south) Overflow pond TRAPEZOIDAL Sta to Sta TRAPEZOIDAL Sta100+90toSta TRAPEZOIDAL Sta101+35toSta TRAPEZOIDAL Sta to Sta TRAPEZOIDAL Sta to L200 TRAPEZOIDAL Start of Chester Creek TRAPEZOIDAL ************************** Volume Depth Runoff Quantity Continuity hectare-m mm ************************** Total Precipitation Surface Runoff Continuity Error (%)

31 ************************** Volume Volume Flow Routing Continuity hectare-m Mliters ************************** External Inflow External Outflow Initial Stored Volume Final Stored Volume Continuity Error (%) ****************************************** Composite Curve Number Computations Report ****************************************** Subbasin {Ditch}.A Area Soil Soil/Surface Description (ha) Group CN > 75% grass cover, Good-Golfcourse B Pasture, grassland, or range, Fair C Pasture, grassland, or range, Fair 9.74 C/D Composite Area & Weighted CN Subbasin {Ditch}.A1-1 Area Soil Soil/Surface Description (ha) Group CN Woods, Good B/C Pasture, grassland, or range, Good 8.15 B Woods, Good B Composite Area & Weighted CN Subbasin {Ditch}.A1-10a -- Area Soil Soil/Surface Description (ha) Group CN Paved parking & roofs 1.01 C 98.00

32 Composite Area & Weighted CN Subbasin {Ditch}.A1-2 Area Soil Soil/Surface Description (ha) Group CN Woods,Good B/C Woods, Good B Composite Area & Weighted CN Subbasin {Ditch}.A1-3 Area Soil Soil/Surface Description (ha) Group CN Woods, Good B Composite Area & Weighted CN Subbasin {Ditch}.A1-4 Area Soil Soil/Surface Description (ha) Group CN Woods, Good B acre lots, 12% impervious 2.07 B Composite Area & Weighted CN Subbasin {Ditch}.A1-5 Area Soil Soil/Surface Description (ha) Group CN Pasture, grassland, or range, Good C Woods, Good B acre lots, 12% impervious B Composite Area & Weighted CN

33 Subbasin {Ditch}.A1-6 Area Soil Soil/Surface Description (ha) Group CN Woods, Good 5.77 B acre lots, 12% impervious 1.92 B acre lots, 12% impervious 2.88 C Pasture, grassland, or range, Good 8.65 C Composite Area & Weighted CN Subbasin {Ditch}.A1-7 Area Soil Soil/Surface Description (ha) Group CN Pasture, grassland, or range, Good 2.99 C Composite Area & Weighted CN Subbasin {Ditch}.A1-7a - Area Soil Soil/Surface Description (ha) Group CN Paved parking & roofs 3.02 C Composite Area & Weighted CN Subbasin {Ditch}.A1-8 Area Soil Soil/Surface Description (ha) Group CN acre lots, 12% impervious 5.16 B Woods, Good 8.61 B acre lots, 12% impervious C Pasture, grassland, or range, Good 8.61 C Composite Area & Weighted CN Subbasin {Ditch}.A1-8a

34 - Area Soil Soil/Surface Description (ha) Group CN Paved parking & roofs 1.71 C Composite Area & Weighted CN Subbasin {Ditch}.A1-9 Area Soil Soil/Surface Description (ha) Group CN Pasture, grassland, or range, Good 3.71 C Woods, Good 5.57 B Pasture, grassland, or range, Good B Composite Area & Weighted CN Subbasin {Ditch}.A1-9a - Area Soil Soil/Surface Description (ha) Group CN Paved parking & roofs 1.08 C Composite Area & Weighted CN Subbasin {Ditch}.A5-2 Area Soil Soil/Surface Description (ha) Group CN Pasture, grassland, or range, Good 7.00 C Composite Area & Weighted CN Subbasin {Ditch}.B1-1 Area Soil Soil/Surface Description (ha) Group CN Pasture, grassland, or range, Good 2.85 B Woods, Good B 55.00

35 Pasture, grassland, or range, Good 0.95 C Composite Area & Weighted CN Subbasin {Ditch}.B1-1a - Area Soil Soil/Surface Description (ha) Group CN Paved parking & roofs 0.63 C Composite Area & Weighted CN Subbasin {Ditch}.B1-2 Area Soil Soil/Surface Description (ha) Group CN Pasture, grassland, or range, Good B Woods, Good 2.27 B Composite Area & Weighted CN Subbasin {Ditch}.B1-2b - Area Soil Soil/Surface Description (ha) Group CN Paved parking & roofs 1.11 C Composite Area & Weighted CN Subbasin {Ditch}.B1-3 Area Soil Soil/Surface Description (ha) Group CN Woods, Good 3.65 B acre lots, 12% impervious 1.83 B Pasture, grassland, or range, Good B Composite Area & Weighted CN Subbasin {Ditch}.B1-3a

36 - Area Soil Soil/Surface Description (ha) Group CN Paved parking & roofs 0.30 C Composite Area & Weighted CN Subbasin {Ditch}.B1-4 Area Soil Soil/Surface Description (ha) Group CN /4 acre lots, 38% impervious 3.85 B Composite Area & Weighted CN Subbasin {Ditch}.B Area Soil Soil/Surface Description (ha) Group CN Pasture, grassland, or range, Good 5.40 C Composite Area & Weighted CN Subbasin {Ditch}.C1-1 Area Soil Soil/Surface Description (ha) Group CN Woods, Good-moderatelywelldrained B/C Pasture, grassland, or range, Good B/C acre lots, 20% impervious B Woods, Good B Pasture, grassland, or range, Good B Paved parking & roofs 1.20 B Composite Area & Weighted CN Subbasin {Ditch}.Ca Area Soil Soil/Surface Description (ha) Group CN

37 Paved parking & roofs 0.39 C Composite Area & Weighted CN Subbasin A Area Soil Soil/Surface Description (ha) Group CN Woods, Good 5.61 B Pasture, grassland, or range, Good 2.59 B Pasture, grassland, or range, Good 0.43 C Composite Area & Weighted CN Subbasin Sub Area Soil Soil/Surface Description (ha) Group CN Composite Area & Weighted CN *************************************************** SCS TR-55 Time of Concentration Computations Report *************************************************** Sheet Flow Equation Tc = (0.007 * ((n * Lf)^0.8)) / ((P^0.5) * (Sf^0.4)) Where: Tc = Time of Concentration (hrs) n = Manning's Roughness Lf = Flow Length (ft) P = 2 yr, 24 hr Rainfall (inches) Sf = Slope (ft/ft) Shallow Concentrated Flow Equation

38 V = * (Sf^0.5) (unpaved surface) V = * (Sf^0.5) (paved surface) V = 15.0 * (Sf^0.5) (grassed waterway surface) V = 10.0 * (Sf^0.5) (nearly bare & untilled surface) V = 9.0 * (Sf^0.5) (cultivated straight rows surface) V = 7.0 * (Sf^0.5) (short grass pasture surface) V = 5.0 * (Sf^0.5) (woodland surface) V = 2.5 * (Sf^0.5) (forest w/heavy litter surface) Tc = (Lf / V) / (3600 sec/hr) Where: Tc = Time of Concentration (hrs) Lf = Flow Length (ft) V = Velocity (ft/sec) Sf = Slope (ft/ft) Channel Flow Equation V = (1.49 * (R^(2/3)) * (Sf^0.5)) / n R = Aq / Wp Tc = (Lf / V) / (3600 sec/hr) Where: Tc = Time of Concentration (hrs) Lf = Flow Length (ft) R = Hydraulic Radius (ft) Aq = Flow Area (ft²) Wp = Wetted Perimeter (ft) V = Velocity (ft/sec) Sf = Slope (ft/ft) n = Manning's Roughness Subbasin {Ditch}.A Shallow Concentrated Flow Computations Subarea A Subarea B Subarea C Flow Length (m):

39 Slope (%): Surface Type: Grass pasture Unpaved Unpaved Velocity (m/sec): Computed Flow Time (minutes): Total TOC (minutes): Subbasin {Ditch}.A1-1 Shallow Concentrated Flow Computations Subarea A Subarea B Subarea C Flow Length (m): Slope (%): Surface Type: Woodland Unpaved Unpaved Velocity (m/sec): Computed Flow Time (minutes): Channel Flow Computations - Subarea A Subarea B Subarea C Manning's Roughness: Flow Length (m): Channel Slope (%): Cross Section Area (m²): Wetted Perimeter (m): Velocity (m/sec): Computed Flow Time (minutes): Total TOC (minutes): 72.98

40 -- Subbasin {Ditch}.A1-10a -- Sheet Flow Computations Subarea A Subarea B Subarea C Manning's Roughness: Flow Length (m): Slope (%): yr, 24 hr Rainfall (mm): Velocity (m/sec): Computed Flow Time (minutes): Channel Flow Computations - Subarea A Subarea B Subarea C Manning's Roughness: Flow Length (m): Channel Slope (%): Cross Section Area (m²): Wetted Perimeter (m): Velocity (m/sec): Computed Flow Time (minutes): Total TOC (minutes): 8.50 Subbasin {Ditch}.A1-2 Shallow Concentrated Flow Computations Subarea A Subarea B Subarea C Flow Length (m): Slope (%): Surface Type: Woodland Grass pasture Unpaved

41 Velocity (m/sec): Computed Flow Time (minutes): Channel Flow Computations - Subarea A Subarea B Subarea C Manning's Roughness: Flow Length (m): Channel Slope (%): Cross Section Area (m²): Wetted Perimeter (m): Velocity (m/sec): Computed Flow Time (minutes): Total TOC (minutes): Subbasin {Ditch}.A1-3 Shallow Concentrated Flow Computations Subarea A Subarea B Subarea C Flow Length (m): Slope (%): Surface Type: Woodland Unpaved Unpaved Velocity (m/sec): Computed Flow Time (minutes): Channel Flow Computations - Subarea A Subarea B Subarea C Manning's Roughness: Flow Length (m): Channel Slope (%): Cross Section Area (m²): Wetted Perimeter (m): Velocity (m/sec):

42 Computed Flow Time (minutes): Total TOC (minutes): Subbasin {Ditch}.A1-4 Shallow Concentrated Flow Computations Subarea A Subarea B Subarea C Flow Length (m): Slope (%): Surface Type: Woodland Grass pasture Unpaved Velocity (m/sec): Computed Flow Time (minutes): Channel Flow Computations - Subarea A Subarea B Subarea C Manning's Roughness: Flow Length (m): Channel Slope (%): Cross Section Area (m²): Wetted Perimeter (m): Velocity (m/sec): Computed Flow Time (minutes): Total TOC (minutes): 18.19

43 Subbasin {Ditch}.A1-5 Shallow Concentrated Flow Computations Subarea A Subarea B Subarea C Flow Length (m): Slope (%): Surface Type: Woodland Unpaved Unpaved Velocity (m/sec): Computed Flow Time (minutes): Channel Flow Computations - Subarea A Subarea B Subarea C Manning's Roughness: Flow Length (m): Channel Slope (%): Cross Section Area (m²): Wetted Perimeter (m): Velocity (m/sec): Computed Flow Time (minutes): Total TOC (minutes): Subbasin {Ditch}.A1-6 Channel Flow Computations - Subarea A Subarea B Subarea C Manning's Roughness: Flow Length (m): Channel Slope (%): Cross Section Area (m²): Wetted Perimeter (m):

44 Velocity (m/sec): Computed Flow Time (minutes): Total TOC (minutes): Subbasin {Ditch}.A1-7 Shallow Concentrated Flow Computations Subarea A Subarea B Subarea C Flow Length (m): Slope (%): Surface Type: Grass pasture Unpaved Unpaved Velocity (m/sec): Computed Flow Time (minutes): Total TOC (minutes): Subbasin {Ditch}.A1-7a - Sheet Flow Computations Subarea A Subarea B Subarea C Manning's Roughness: Flow Length (m): Slope (%): yr, 24 hr Rainfall (mm): Velocity (m/sec):

45 Computed Flow Time (minutes): Channel Flow Computations - Subarea A Subarea B Subarea C Manning's Roughness: Flow Length (m): Channel Slope (%): Cross Section Area (m²): Wetted Perimeter (m): Velocity (m/sec): Computed Flow Time (minutes): Total TOC (minutes): Subbasin {Ditch}.A1-8 Shallow Concentrated Flow Computations Subarea A Subarea B Subarea C Flow Length (m): Slope (%): Surface Type: Grass pasture Unpaved Unpaved Velocity (m/sec): Computed Flow Time (minutes): Total TOC (minutes): Subbasin {Ditch}.A1-8a

46 - Sheet Flow Computations Subarea A Subarea B Subarea C Manning's Roughness: Flow Length (m): Slope (%): yr, 24 hr Rainfall (mm): Velocity (m/sec): Computed Flow Time (minutes): Channel Flow Computations - Subarea A Subarea B Subarea C Manning's Roughness: Flow Length (m): Channel Slope (%): Cross Section Area (m²): Wetted Perimeter (m): Velocity (m/sec): Computed Flow Time (minutes): Total TOC (minutes): Subbasin {Ditch}.A1-9 Shallow Concentrated Flow Computations Subarea A Subarea B Subarea C Flow Length (m): Slope (%): Surface Type: Grass pasture Unpaved Unpaved Velocity (m/sec): Computed Flow Time (minutes):

47 Total TOC (minutes): Subbasin {Ditch}.A1-9a - Sheet Flow Computations Subarea A Subarea B Subarea C Manning's Roughness: Flow Length (m): Slope (%): yr, 24 hr Rainfall (mm): Velocity (m/sec): Computed Flow Time (minutes): Channel Flow Computations - Subarea A Subarea B Subarea C Manning's Roughness: Flow Length (m): Channel Slope (%): Cross Section Area (m²): Wetted Perimeter (m): Velocity (m/sec): Computed Flow Time (minutes): Total TOC (minutes): Subbasin {Ditch}.A5-2

48 Shallow Concentrated Flow Computations Subarea A Subarea B Subarea C Flow Length (m): Slope (%): Surface Type: Grass pasture Unpaved Unpaved Velocity (m/sec): Computed Flow Time (minutes): Total TOC (minutes): Subbasin {Ditch}.B1-1 Shallow Concentrated Flow Computations Subarea A Subarea B Subarea C Flow Length (m): Slope (%): Surface Type: Woodland Unpaved Unpaved Velocity (m/sec): Computed Flow Time (minutes): Total TOC (minutes): Subbasin {Ditch}.B1-1a - Sheet Flow Computations

49 Subarea A Subarea B Subarea C Manning's Roughness: Flow Length (m): Slope (%): yr, 24 hr Rainfall (mm): Velocity (m/sec): Computed Flow Time (minutes): Total TOC (minutes): Subbasin {Ditch}.B1-2 Shallow Concentrated Flow Computations Subarea A Subarea B Subarea C Flow Length (m): Slope (%): Surface Type: Woodland Unpaved Unpaved Velocity (m/sec): Computed Flow Time (minutes): Total TOC (minutes): Subbasin {Ditch}.B1-2b - Sheet Flow Computations

50 Subarea A Subarea B Subarea C Manning's Roughness: Flow Length (m): Slope (%): yr, 24 hr Rainfall (mm): Velocity (m/sec): Computed Flow Time (minutes): Total TOC (minutes): 8.57 Subbasin {Ditch}.B1-3 Shallow Concentrated Flow Computations Subarea A Subarea B Subarea C Flow Length (m): Slope (%): Surface Type: Grass pasture Unpaved Unpaved Velocity (m/sec): Computed Flow Time (minutes): Total TOC (minutes): Subbasin {Ditch}.B1-3a - Sheet Flow Computations Subarea A Subarea B Subarea C

51 Manning's Roughness: Flow Length (m): Slope (%): yr, 24 hr Rainfall (mm): Velocity (m/sec): Computed Flow Time (minutes): Total TOC (minutes): 3.59 Subbasin {Ditch}.B1-4 Shallow Concentrated Flow Computations Subarea A Subarea B Subarea C Flow Length (m): Slope (%): Surface Type: Grass pasture Unpaved Unpaved Velocity (m/sec): Computed Flow Time (minutes): Total TOC (minutes): Subbasin {Ditch}.B Shallow Concentrated Flow Computations Subarea A Subarea B Subarea C Flow Length (m):

52 Slope (%): Surface Type: Grass pasture Unpaved Unpaved Velocity (m/sec): Computed Flow Time (minutes): Total TOC (minutes): Subbasin {Ditch}.C1-1 Shallow Concentrated Flow Computations Subarea A Subarea B Subarea C Flow Length (m): Slope (%): Surface Type: Woodland Unpaved Unpaved Velocity (m/sec): Computed Flow Time (minutes): Channel Flow Computations - Subarea A Subarea B Subarea C Manning's Roughness: Flow Length (m): Channel Slope (%): Cross Section Area (m²): Wetted Perimeter (m): Velocity (m/sec): Computed Flow Time (minutes): Total TOC (minutes): 61.21

53 Subbasin {Ditch}.Ca Sheet Flow Computations Subarea A Subarea B Subarea C Manning's Roughness: Flow Length (m): Slope (%): yr, 24 hr Rainfall (mm): Velocity (m/sec): Computed Flow Time (minutes): Total TOC (minutes): Subbasin A Shallow Concentrated Flow Computations Subarea A Subarea B Subarea C Flow Length (m): Slope (%): Surface Type: Woodland Unpaved Unpaved Velocity (m/sec): Computed Flow Time (minutes): Total TOC (minutes): 19.21

54 Subbasin Sub Sheet Flow Computations Subarea A Subarea B Subarea C Manning's Roughness: Flow Length (m): Slope (%): yr, 24 hr Rainfall (mm): Velocity (m/sec): Computed Flow Time (minutes): Total TOC (minutes): *********************** Subbasin Runoff Summary *********************** -- Subbasin Total Total Peak Weighted Time of ID Precip Runoff Runoff Curve Concentration mm mm cms Number days hh:mm:ss -- {Ditch}.A :54:10 {Ditch}.A :12:58 {Ditch}.A1-10a :08:30 {Ditch}.A :55:47 {Ditch}.A :13:07 {Ditch}.A :18:11 {Ditch}.A :33:23 {Ditch}.A :17:33 {Ditch}.A :12:49 {Ditch}.A1-7a :54:17 {Ditch}.A :20:21 {Ditch}.A1-8a :52:20 {Ditch}.A :19:52

55 {Ditch}.A1-9a :35:12 {Ditch}.A :06:52 {Ditch}.B :20:28 {Ditch}.B1-1a :18:01 {Ditch}.B :15:00 {Ditch}.B1-2b :08:34 {Ditch}.B :09:04 {Ditch}.B1-3a :05:00 {Ditch}.B :05:27 {Ditch}.B :54:55 {Ditch}.C :01:12 {Ditch}.Ca :05:20 A :19:12 Sub :52:22 -- ****************** Node Depth Summary ****************** Node Average Maximum Maximum Time of Max Total Total Retention ID Depth Depth HGL Occurrence Flooded Time Time Attained Attained Attained Volume Flooded m m m days hh:mm ha-mm minutes hh:mm:ss : :00: : :00: : :00: : :00: : :00: : :00: : :00: : :00: : :00: : :00: : :00: : :00: : :00: : :00: : :00: : :00: : :00:00

56 : :00: : :00: : :00: : :00: : :00:00 30a : :00: : :00: : :00: : :00: : :00:00 6a : :00:00 Jun : :00:00 Jun : :00:00 Jun : :00:00 Sta : :00:00 Sta : :00:00 Sta North : :00:00 Sta : :00:00 Sta : :00:00 Sta : :00:00 Sta : :00:00 Sta : :00:00 Sta : :00:00 Sta North : :00:00 Sta : :00:00 Sta North : :00:00 Sta : :00:00 Sta : :00:00 Sta : :00:00 Sta North : :00:00 FarmUnderpassOutfall : :00:00 OutfallSTA : :00:00 Out-Sta : :00:00 PumpStationOutfall : :00:00 ***************** Node Flow Summary ***************** Node Element Maximum Peak Time of Maximum Time of Peak ID Type Lateral Inflow Peak Inflow Flooding Flooding Inflow Occurrence Overflow Occurrence

57 cms cms days hh:mm cms days hh:mm JUNCTION : JUNCTION : JUNCTION : :23 4 JUNCTION : JUNCTION : JUNCTION : JUNCTION : JUNCTION : JUNCTION : JUNCTION : JUNCTION : JUNCTION : JUNCTION : JUNCTION : JUNCTION : JUNCTION : JUNCTION : JUNCTION : JUNCTION : JUNCTION : JUNCTION : JUNCTION : a JUNCTION : JUNCTION : JUNCTION : JUNCTION : JUNCTION : a JUNCTION : Jun-57 JUNCTION : Jun-60 JUNCTION : Jun-61 JUNCTION : Sta JUNCTION : Sta JUNCTION : Sta North JUNCTION : Sta JUNCTION : Sta JUNCTION : Sta JUNCTION : :29 Sta JUNCTION : :24 Sta JUNCTION : Sta JUNCTION : Sta North JUNCTION : :21 Sta JUNCTION :

58 Sta North JUNCTION : :26 Sta JUNCTION : :22 Sta JUNCTION : :12 Sta JUNCTION : Sta North JUNCTION : :22 FarmUnderpassOutfall OUTFALL : OutfallSTA107 OUTFALL : Out-Sta101 OUTFALL : PumpStationOutfall OUTFALL : *********************** Outfall Loading Summary *********************** Outfall Node ID Flow Average Peak Frequency Flow Inflow (%) cms cms FarmUnderpassOutfall OutfallSTA Out-Sta PumpStationOutfall System ***************** Link Flow Summary ***************** Link ID Element Time of Maximum Length Peak Flow Design Ratio of Ratio of Total Reported Type Peak Flow Velocity Factor during Flow Maximum Maximum Time Condition Occurrence Attained Analysis Capacity /Design Flow Surcharged days hh:mm m/sec cms cms Flow Depth minutes Chester Creek Tributary CHANNEL 0 08: Calculated Chester Creek US of Highway CHANNEL 0 08: Calculated

59 Chester Street Culvert CONDUIT 0 09: > CAPACITY Cross Sta CONDUIT 0 08: Calculated Cross Sta CONDUIT 0 08: Calculated Cross CONDUIT 0 08: Calculated Cross CONDUIT 0 08: Calculated Cross CONDUIT 0 08: Calculated Cross CONDUIT 0 08: Calculated Cross CONDUIT 0 08: Calculated Cross CONDUIT 0 09: SURCHARGED Culvert across Mclean Street CONDUIT 0 08: Calculated Culvert from Sta to Sta CONDUIT 0 08: Calculated Ex. Underpass_Bridge Sta 124 CHANNEL 0 08: FLOODED Farm underpass to south ditch CHANNEL 0 10: Calculated FarmCrossingUnderPass@Sta CONDUIT 0 10: > CAPACITY L200 to Sta 107 CHANNEL 0 08: Calculated L300 line to Sta 124 (south) CHANNEL 0 10: Calculated Link-66 CHANNEL 0 08: Calculated Link-68 CONDUIT 0 15: Calculated Link-69 CHANNEL 0 08: FLOODED Link-70 CHANNEL 0 10: FLOODED Link-71 CHANNEL 0 10: Calculated Overflow to farm underpass CHANNEL 0 10: FLOODED

60 Pr. L200 CONDUIT 0 08: Calculated CONDUIT 0 08: SURCHARGED Pump Station to Fraser River CHANNEL 0 08: Calculated Pump Station to Sta (south) CHANNEL 0 10: Calculated Railway_underpass CONDUIT 0 15: Calculated Sta to Mclean Street CHANNEL 0 08: Calculated Sta to Sta DIRECT 0 08: Sta 107 to Sta 107 outfall CHANNEL 0 08: Calculated Sta to Sta CHANNEL 0 08: Calculated Sta 10740to Sta 107 CHANNEL 0 08: Calculated Sta to Sta 107 CHANNEL 0 08: Calculated Sta to DS pump station CHANNEL 0 08: Calculated Sta to Tributaries CHANNEL 0 08: Calculated Sta 114 to L300 line (south) CHANNEL 0 08: Calculated Sta to Chester Street CHANNEL 0 09: Calculated Sta 119 to Chester Street CHANNEL 0 09: FLOODED Sta 119 to Sta 124 CHANNEL 0 09: FLOODED Sta 124 (South) CHANNEL 0 10: Calculated Sta 124 (south) Overflow pond CHANNEL 0 10: Calculated Sta to Sta CHANNEL 0 08: FLOODED Sta100+90toSta CHANNEL 0 08: Calculated Sta101+35toSta CHANNEL 0 08: Calculated Sta to Sta CHANNEL 0 08:

61 Calculated Sta to L200 CHANNEL 0 08: Calculated Start of Chester Creek CHANNEL 0 08: Calculated Pump-02 PUMP 0 09: ******************************** Highest Flow Instability Indexes ******************************** Link Cross (70) Link Sta to DS pump station (70) Link Cross Sta (61) Link Link-68 (39) Link Railway_underpass (37) WARNING 107 : Initial water surface elevation defined for Junction Jun-61 is below junction invert elevation. Assumed initial water surface elevation equal to invert elevation. WARNING 116 : Conduit inlet invert elevation defined for Conduit Farm underpass to south ditch is below upstream node invert elevation. Assumed conduit inlet invert elevation equal to upstream node invert elevation. WARNING 117 : Conduit outlet invert elevation defined for Conduit Pump Station to Sta (south) is below downstream node invert elevation. Assumed conduit outlet invert elevation equal to downstream node invert elevation. WARNING 004 : Minimum elevation drop used for Conduit Sta to Sta WARNING 004 : Minimum elevation drop used for Conduit Sta 124 (south) Overflow pond. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 3. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 4. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 5. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 8. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 9. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 10. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 15. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 19.

62 WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 20. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 21. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 32. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 33. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node 35. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node Jun-61. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node Sta WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node Sta WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node Sta WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node Sta WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node Sta WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node Sta WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node Sta North. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node Sta WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node Sta North. WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node Sta WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node Sta WARNING 002 : Max/rim elevation (depth) increased to account for connecting conduit height dimensions for Node Sta North. Analysis began on: Fri Nov 10 10:17: Analysis ended on: Fri Nov 10 10:18: Total elapsed time: 00:00:10

63 APPENDIX D MODEL RESULTS

64 SCENARIO 1 Element Length Inlet Outlet Total Average Pipe Pipe Pipe Manning's Entrance Exit/Bend Additional Initial Peak Time of Max Travel Design Max Flow / Max Total Max Reported ID Invert Invert Drop Slope Shape Diameter Width Roughness Losses Losses Losses Flow Flow Peak Flow Time Flow Design Flow Flow Depth / Time Flow Condition Elevation Elevation or Height Flow Velocity Capacity Ratio Total Depth Surcharged Depth Occurrence Ratio (m) (m) (m) (m) (%) (mm) (mm) (cms) (cms) (days hh:mm) (m/sec) (min) (cms) (min) (m) Chester Street Culvert CIRCULAR : > CAPACITY Cross Sta CIRCULAR : Calculated Cross CIRCULAR : Calculated Cross CIRCULAR : Calculated Cross CIRCULAR : Calculated Cross CIRCULAR : SURCHARGED Cross CIRCULAR : SURCHARGED Culvert from Sta to Sta CIRCULAR : Calculated FarmCrossingUnderPass@Sta CIRCULAR : > CAPACITY Pr. L CIRCULAR : Calculated CIRCULAR : SURCHARGED Railway_underpass Horizontal Ellipse : Calculated

65 Element Length Inlet Outlet Total Average Channel Channel Channel Left Channel Right Entrance Exit/Bend Additional Lengthening Peak Time of Max Travel Design Max Flow / Max Total Max Reported ID Invert Invert Drop Slope Type Height Width Overbank Manning's Overbank Losses Losses Losses Factor Flow Peak Flow Time Flow Design Flow Flow Depth / Time Flow Condition Elevation Elevation Manning's Roughness Manning's Flow Velocity Capacity Ratio Total Depth Surcharged Depth Roughness Roughness Occurrence Ratio (m) (m) (m) (m) (%) (m) (m) (cms) (days hh:mm) (m/sec) (min) (cms) (min) (m) Chester Creek Tributary Trapezoidal : Calculated Chester Creek US of Highway Trapezoidal : Calculated Ex. Underpass_Bridge Sta Rectangular : FLOODED Farm underpass to south ditch Trapezoidal : Calculated L200 to Sta Trapezoidal : Calculated L300 line to Sta 124 (south) Trapezoidal : Calculated Link Rectangular : Calculated Link Trapezoidal : FLOODED Link Trapezoidal : FLOODED Link Trapezoidal : Calculated Overflow to farm underpass Trapezoidal : FLOODED Pump Station to Fraser River Rectangular : Calculated Pump Station to Sta (south) Trapezoidal : Calculated Sta to Mclean Street Trapezoidal : Calculated Sta 107 to Sta 107 outfall Trapezoidal : Calculated Sta to Sta Trapezoidal : Calculated Sta 10740to Sta Trapezoidal : Calculated Sta to Sta Trapezoidal : Calculated Sta to DS pump station Trapezoidal : Calculated Sta to Tributaries Trapezoidal : Calculated Sta 114 to L300 line (south) Trapezoidal : Calculated Sta to Chester Street Trapezoidal : Calculated Sta 119 to Chester Street Trapezoidal : FLOODED Sta 119 to Sta Trapezoidal : FLOODED Sta 124 (South) Rectangular : Calculated Sta 124 (south) Overflow pond Trapezoidal : Calculated Sta to Sta Trapezoidal : FLOODED Sta100+90toSta Trapezoidal : Calculated Sta101+35toSta Trapezoidal : Calculated Sta to Sta Trapezoidal : Calculated Sta to L Trapezoidal : Calculated Start of Chester Creek Trapezoidal : Calculated

66 SN Element X Coordinate Y Coordinate Description Invert Boundary Flap Fixed Peak Peak Maximum Maximum ID Elevation Type Gate Water Inflow Lateral HGL Depth HGL Elevation Elevation Inflow Attained Attained (m) (m) (cms) (cms) (m) (m) 1 FarmUnderpassOutfall NORMAL NO OutfallSTA NORMAL NO Out-Sta NORMAL NO PumpStationOutfall FIXED NO

67 SN Element Invert Ground/Rim Ground/Rim Initial Initial Surcharge Surcharge Ponded Minimum Peak Peak Maximum Maximum Maximum Minimum Average Average Time of Time of Total Total ID Elevation (Max) (Max) Water Water Elevation Depth Area Pipe Cover Inflow Lateral HGL HGL Surcharge Freeboard HGL HGL Maximum Peak Flooded Time Elevation Offset Elevation Depth Inflow Elevation Depth Depth Attained Elevation Depth HGL Flooding Volume Flooded Attained Attained Attained Attained Attained Occurrence Occurrence (m) (m) (m) (m) (m) (m) (m) (m²) (mm) (cms) (cms) (m) (m) (m) (m) (m) (m) (days hh:mm) (days hh:mm) (ha-mm) (minutes) : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : a : : : : : : : : : : a : : : : : : : : Sta : : Sta : : Sta North : : Sta : : Sta : : Sta : : Sta : : Sta : : Sta : : Sta North : : Sta : : Sta North : : Sta : : Sta : : Sta : : Sta North : :

68 SN Element Description Area Drainage Weighted Rain Gage Total Total Peak Time ID Node ID Curve ID Precipitation Runoff Runoff of Number Concentration (ha) (mm) (mm) (cms) (days hh:mm:ss) 1 {Ditch}.A Sta Rain Gage :54:10 2 {Ditch}.A1-1 UpperChesterCreekCatchment Rain Gage :12:58 3 {Ditch}.A1-10a Rain Gage :08:30 4 {Ditch}.A1-2 UpperChesterCreekCatchment Rain Gage :55:47 5 {Ditch}.A Rain Gage :13:07 6 {Ditch}.A Rain Gage :18:11 7 {Ditch}.A Sta Rain Gage :33:23 8 {Ditch}.A Sta Rain Gage :17:33 9 {Ditch}.A Sta North Rain Gage :12:49 10 {Ditch}.A1-7a 3.02 Sta North Rain Gage :54:17 11 {Ditch}.A Sta Rain Gage :20:21 12 {Ditch}.A1-8a 1.71 Sta Rain Gage :52:20 13 {Ditch}.A Sta North Rain Gage :19:52 14 {Ditch}.A1-9a 1.08 Sta North Rain Gage :35:12 15 {Ditch}.A Sta Rain Gage :06:52 16 {Ditch}.B Rain Gage :20:28 17 {Ditch}.B1-1a Rain Gage :18:01 18 {Ditch}.B Rain Gage :15:00 19 {Ditch}.B1-2b Rain Gage :08:34 20 {Ditch}.B Rain Gage :09:04 21 {Ditch}.B1-3a Rain Gage :05:00 22 {Ditch}.B Rain Gage :05:27 23 {Ditch}.B Rain Gage :54:55 24 {Ditch}.C Rain Gage :01:12 25 {Ditch}.Ca Rain Gage :05:20 26 A Rain Gage :19:12 27 Sub Sta Rain Gage :52:22

69 SCENARIO 2 Element Length Inlet Outlet Total Average Pipe Pipe Pipe Manning's Entrance Exit/Bend Additional Initial Flap Lengthening Peak Design Max Total Max Reported ID Invert Invert Drop Slope Shape Diameter Width Roughness Losses Losses Losses Flow Gate Factor Flow Flow Flow Depth / Time Flow Condition Elevation Elevation or Height Capacity Total Depth Surcharged Depth Ratio (m) (m) (m) (m) (%) (mm) (mm) (cms) (cms) (cms) (min) (m) Chester Street Culvert CIRCULAR NO > CAPACITY Cross Sta CIRCULAR NO Calculated Cross CIRCULAR NO Calculated Cross CIRCULAR NO Calculated Cross CIRCULAR NO Calculated Cross CIRCULAR NO Calculated Cross CIRCULAR NO Calculated Culvert from Sta to Sta CIRCULAR NO Calculated FarmCrossingUnderPass@Sta CIRCULAR NO > CAPACITY Pr. L CIRCULAR NO Calculated CIRCULAR NO SURCHARGED

70 Element Length Inlet Outlet Total Average Channel Channel Channel Left Channel Right Entrance Exit/Bend Additional Initial Flap Lengthening Peak Time of Max Travel Design Max Flow / Max Total Max Reported ID Invert Invert Drop Slope Type Height Width Overbank Manning's Overbank Losses Losses Losses Flow Gate Factor Flow Peak Flow Time Flow Design Flow Flow Depth / Time Flow Condition Elevation Elevation Manning's Roughness Manning's Flow Velocity Capacity Ratio Total Depth Surcharged Depth Roughness Roughness Occurrence Ratio (m) (m) (m) (m) (%) (m) (m) (cms) (cms) (days hh:mm) (m/sec) (min) (cms) (min) (m) Chester Creek Tributary Trapezoidal NO : Calculated Chester Creek US of Highway Trapezoidal NO : Calculated Ex. Underpass_Bridge Sta Rectangular NO : FLOODED Farm underpass to south ditch Trapezoidal NO : Calculated Floodgate Rectangular NO : > CAPACITY L200 to Sta Trapezoidal NO : Calculated L300 line to Sta 124 (south) Trapezoidal NO : Calculated Link Rectangular NO : Calculated Link Trapezoidal NO : FLOODED Link Trapezoidal NO : Calculated Link Trapezoidal NO : Calculated Overflow to farm underpass Trapezoidal NO : FLOODED Pump Station to Fraser River Rectangular NO : Calculated Pump Station to Sta (south) Trapezoidal NO : Calculated Sta to Mclean Street Trapezoidal NO : Calculated Sta 107 to Sta 107 outfall Trapezoidal NO : Calculated Sta to Sta Trapezoidal NO : Calculated Sta 10740to Sta Trapezoidal NO : Calculated Sta to Sta Trapezoidal NO : Calculated Sta to DS pump station Trapezoidal NO : Calculated Sta to Tributaries Trapezoidal NO : Calculated Sta 114 to L300 line (south) Trapezoidal NO : Calculated Sta to Chester Street Trapezoidal NO : Calculated Sta 119 to Chester Street Trapezoidal NO : FLOODED Sta 119 to Sta Trapezoidal NO : FLOODED Sta 124 (South) Rectangular NO : Calculated Sta 124 (south) Overflow pond Trapezoidal NO : Calculated Sta to Sta Trapezoidal NO : FLOODED Sta100+90toSta Trapezoidal NO : Calculated Sta101+35toSta Trapezoidal NO : Calculated Sta to Sta Trapezoidal NO : Calculated Sta to L Trapezoidal NO : Calculated Start of Chester Creek Trapezoidal NO : Calculated

71 SN Element Invert Boundary Flap Fixed Peak Peak Maximum Maximum ID Elevation Type Gate Water Inflow Lateral HGL Depth HGL Elevation Elevation Inflow Attained Attained (m) (m) (cms) (cms) (m) (m) 1 FarmUnderpassOutfall 2.83 NORMAL NO OutfallSTA NORMAL NO Out-Sta NORMAL NO PumpStationOutfall 2.00 FIXED NO

72 SN Invert Ground/Rim Ground/Rim Initial Initial Surcharge Surcharge Ponded Minimum Peak Peak Maximum Maximum Maximum Minimum Average Average Time of Time of Total Total Elevation (Max) (Max) Water Water Elevation Depth Area Pipe Cover Inflow Lateral HGL HGL Surcharge Freeboard HGL HGL Maximum Peak Flooded Time Elevation Offset Elevation Depth Inflow Elevation Depth Depth Attained Elevation Depth HGL Flooding Volume Flooded Attained Attained Attained Attained Attained Occurrence Occurrence (m) (m) (m) (m) (m) (m) (m) (m²) (mm) (cms) (cms) (m) (m) (m) (m) (m) (m) (days hh:mm) (days hh:mm) (ha-mm) (minutes) : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : :

73 SN Element Description Area Drainage Weighted Rain Gage Total Total Peak Time ID Node ID Curve ID Precipitation Runoff Runoff of Number Concentration (ha) (mm) (mm) (cms) (days hh:mm:ss) 1 {Ditch}.A Sta Rain Gage :54:10 2 {Ditch}.A1-1 UpperChesterCreekCatchment Rain Gage :12:58 3 {Ditch}.A1-10a Rain Gage :08:30 4 {Ditch}.A Rain Gage :20:28 5 {Ditch}.A1-2 UpperChesterCreekCatchment Rain Gage :55:47 6 {Ditch}.A Rain Gage :13:07 7 {Ditch}.A Rain Gage :18:11 8 {Ditch}.A Sta Rain Gage :33:23 9 {Ditch}.A Sta Rain Gage :17:33 10 {Ditch}.A Sta North Rain Gage :12:49 11 {Ditch}.A1-7a 3.02 Sta North Rain Gage :54:17 12 {Ditch}.A Sta Rain Gage :20:21 13 {Ditch}.A1-8a 1.71 Sta Rain Gage :52:20 14 {Ditch}.A Sta North Rain Gage :19:52 15 {Ditch}.A1-9a 1.08 Sta North Rain Gage :35:12 16 {Ditch}.A Sta Rain Gage :06:52 17 {Ditch}.B Rain Gage :15:00 18 {Ditch}.B1-1a Rain Gage :18:01 19 {Ditch}.B Rain Gage :09:04 20 {Ditch}.B1-2b Rain Gage :08:34 21 {Ditch}.B Rain Gage :05:27 22 {Ditch}.B1-3a Rain Gage :05:00 23 {Ditch}.B Rain Gage :54:55 24 {Ditch}.C Rain Gage :01:12 25 {Ditch}.Ca Rain Gage :05:20 26 A * :19:12 27 Sub Sta Rain Gage :52:22

74 APPENDIX E REVIEW OF Q200 DESIGN FLOWS

75

76

77 APPENDIX F AVERAGE TWO-YEAR DESIGN VELOCITIES

78 Table 1: Velocity summary table for culverts greater than 24.4 m in length