City of Duncan

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CITY OF DUNCAN

Agenda Special Committee of the Whole Meeting Monday, May 30, 2011 @ 6:45 p.m. Committee Room, City Hall 200 Craig Street

Page # 1. Approval of Agenda 1 2. Introduction of Late Items 3. Delegations 3.1. Dayton & Knight – Options for the detail design of the flood pumps 2-47 at the Lee Street dyke. Please note: copies of the Preliminary Environmental Assessment & Geotechnical Desktop Review are available in Councillors’ office. 3.2. Boulevard Transportation Group – Trunk Road/Canada Avenue & 48-64 Trunk Road/Cowichan Way 4. New Business 5. Question and Answer 6. Adjournment

Special Committee of the Whole Agenda – May 30, 2011 Page 1 of 1 OPUS DAYTONKNIGHT CONSULTANTS LTD

Opus DaytonKnight Consultants Ltd. May 30, 2011 Page 2 of 64 OPUS DAYTONKNIGHT CONSULTANTS LTD

Introduction Page 3 of 64

Scope : Design Pump Station to drain slough, 1:200 year return with a safety margin. 2 OPUS DAYTONKNIGHT CONSULTANTS LTD

Stormwater Modelling Page 4 of 64

Currently OpusDK is performing a study for the City assessing stormwater system. 2 OPUS DAYTONKNIGHT CONSULTANTS LTD

TwoThird Options Option

MARCHMONT FLOOD PUMP STATION EXPANSION OPTION 3 Page 5

LEE STREET FLOOD of

PUMP STATION OPTION 1 64

MCKINSTRY FLOOD PUMP STATION OPTION 2 TwoThird pump option station proposed, options Marchmont were proposed.Pump Station Lee Street Expansion. and McKinstry Pump Stations. OPUS DAYTONKNIGHT CONSULTANTS LTD

Required Pumping

MARCHMONT FLOOD PUMP STATION EXPANSION OPTION 3 Page 2.2 m3/s 6

LEE STREET FLOOD of

PUMP STATION OPTION 1 64

MCKINSTRY FLOOD PUMP STATION OPTION 2 0.6 m3/s – 200YR. OPUS DAYTONKNIGHT CONSULTANTS LTD

Marchmont Pump Station Upgrade Option

MARCHMONT FLOOD PUMP STATION EXPANSION OPTION 3 Page 7

LEE STREET FLOOD of

PUMP STATION OPTION 1 64

NEEDED: 2.4 m3/s MCKINSTRY FLOOD AVAILABLE: 0.82 m3/s PUMP STATION OPTION 2 Marchmont Pump Station Upgrade: Add 1.58 m³/s in 2 pumps. 2 OPUS DAYTONKNIGHT CONSULTANTS LTD

Option Review and Cost Estimates

 Cost Estimates

Upgrade Description Cost Estimate Annual Option Financing (after grant) Option 1 Lee Street Screw Pump $1.57M $21.20 Station

Option 2 McKinstry Road Pump $1.24M $13.30 Station

Option 3 Marchmont Pump Station $1.55M $20.60 Page

(Scenario 1) Upgrade 8 of 64 Option 3 Marchmont Pump Station $1.81M $26.70 (Scenario 2) Upgrade OPUS DAYTONKNIGHT CONSULTANTS LTD

Option Review and Conclusions

 Positives of Option 3 (Scenario 2)

- Provides Attenuation for Flooding for the main catchment area in the East of the City - Benefit to all 92 Ha of the City east of the Railway tracks instead of 19 Ha catchment surrounding and contributing to the Lee Street Slough Section of Fish Gut Alley - Takes Advantage of Storage Capacity of Lee St. Slough Section of Fish Gut Alley - Includes full Upgrade of Marchmont Pump Station and takes advantage of the expansion capacity planned into the original pump station design - Significantly reduces the environmental and geotechnical risks of construction in the Slough - Pump Station is in works yard. Page

 Negatives of Option 3 (Scenario 2) 9 of 64 - The Cost difference could be up to 30% over construction of the least cost option for a drainage pump station in the Slough OPUS DAYTONKNIGHT CONSULTANTS LTD

Recommendations

 Recommendations 1. Upgrade Marchmont Pump Station to provide pumping capacity for the 100 year return storm for the two catchment areas east of the Railway tracks in the City of Duncan. This is Option 3 – Scenario 2. 2. Connect the Lee Street Slough Section of the Fish Gut Alley Slough to the Marchmont Pump Station and set a maximum water level for the Slough during severe storm events. Page 10 of 64 OPUS DAYTONKNIGHT CONSULTANTS LTD Page 11 of 64 Page 12 of 64

TECHNICAL MEMORANDUM (DRAFT 2)

To: Abbas Farabakhsh, A.Sc.T. Director of Public Works

From: Opus DaytonKnight Consultants Ltd.

Date: May 26, 2011

RE: Lee Street Flood Pumps

The following memorandum provides a pre-design review of the City of Duncan Flood Pump Station location to support the detailed design to follow.

SUMMARY AND CONCLUSION

The best apparent option for the selection of the Flood Pump is for the City to upgrade the Marchmont Pump Station to protect the City‟s 92 ha of floodplain catchment, which is located east of the railway tracks and south of the District of North Cowichan municipal boundary. This conclusion is given for the following reasons:

1. Flood protection currently provided by the Marchmont Pump Station without detention storage allows for 0.82 m3/s or a drainage capacity of 0.9 m3/s-km2 for the 92 ha of floodplain catchment. This is insufficient to protect the City of Duncan lowland from a 1 in 5 year flood during high water conditions in the Cowichan River and backwater conditions in Somenos Creek.

2. Although in the same flood plain, the Lee Street section of Fish Gut Alley Creek and McKinstry drainage areas are separate from the Marchmont Pump Station catchment. In high water level in the Cowichan River, the Lee Street section of Fish Gut Alley slough is therefore, at higher risk of flooding than the Marchmont drainage system, since it is provided with only gravity drainage from the slough to the river.

3. Since gravity drainage is not available to the low lying dyke protected areas during high water level conditions in the Cowichan River, flood protection should be provided for at least a 25 year return storm or greater; flood protection for the 100 year return storm is recommended.

4. Flood Pump solutions that reduce the flood risk in McKinstry Road catchment (Options 1 and 2) do not reduce the flood risk for the Marchmont drainage (during high water conditions on the Cowichan River).

5. Connection of the Lee Street section of Fish Gut Alley Creek slough to the Marchmont Flood Pump Station provides a drainage outlet for the McKinstry Road runoff and the slough

catchment during high water level river stages, which interrupts gravity drainage from the slough.

6. The lowest impact option to achieve greatest environmental and societal benefit would be an option that connects the Lee Street section of Fish Gut Alley slough to an upgraded Marchmont Pump Station. This option could maintain the current drainage solution for McKinstry Road runoff and minimize impact to the slough habitat while increasing overall flood protection to the floodplain.

7. Option 1 construction of a new pump station on the Lee Street section Fish Gut Alley slough is estimated at $1.57 M. The pump is to reduce the potential for flooding of the slough only, and has limited benefits. The City will still require an upgrade of the Marchmont Pump Station to alleviate flooding potential for the main portion of the catchment area.

8. The Option 2a construction cost estimate to construct a new pump station at McKinstry Road is approximately $1.24M, which is lower than the Option 1 estimated cost of a new screw pump at the Lee Street dyke. A variation of this option (Option 2b) was not costed since it required more infrastructure and would have greater impact on the environment. It includes pumping the McKinstry Road run-off to the Marchmont Flood Pump Station and a Marchmont Pump Station upgrade.

9. The Option 3, Scenario 1 estimated construction cost to upgrade the Marchmont pump station to handle the 5 year return storm for the entire 92 ha catchment, including drainage from the Fish Gut Alley catchment is $1.55M. This is only slightly lower than the cost to construct Option 1, a new screw pump station in Fish Gut Alley slough. The addition of 17,000 m3 of active storage to the slough would allow Option 3 Scenario 1, to provide a 100 year protection. The added storage may not be acceptable or possible since a significant portion of the run-off from the 92 ha catchment would have to be diverted into the slough by a new large diameter pipe connection upstream from the outlet. The beaver dam would need to be removed and the fish habitat would be impacted by the storage.

10. The Option 3, Scenario 2 estimated construction cost to upgrade the Marchmont Pump Station to handle the 100 year return storm for the entire 92 ha catchment, including drainage from the Lee Street section of Fish Gut Alley catchment is $1.81M. Option 3, Scenario 2 is the only option providing 100 year protection to the dyked flood plain in the City of Duncan.

1.0 INTRODUCTION

The purpose of the technical memorandum is to recommend a flood pump station size and location for the McKinstry Road and the Lee Street section of Fish Gut Alley slough catchment. Fish Gut Alley Creek lies within the City boundary and is referred to at the Lee Street slough section. The slough is located within the Cowichan River dyke on the south and an old dyke referenced as the Lee Street section on the north. The old section of dyke is now overgrown. Currently the slough and the catchment drain by gravity to the Cowichan River, but, during flood conditions in the Cowichan River, the flap gates on the outlet close and the slough does not have a drainage outlet.

In a 2010 report by Northwest Hydraulics Consultants (nhc), a flood pump station was recommended and two site selection options were proposed (illustrated in Figure 1-1) as follows:

1) the east end of the Fish Gut Alley slough on the Cowichan River Dyke - referred to as the Lee Street Site; and

2) the west end of Fish Gut Alley slough at the foot of McKinstry Road - referred to as the McKinstry Road site.

The Lee Street site flood pump was proposed as a screw impeller fish friendly pump station that would discharge from the slough to the Cowichan River. The McKinstry Road site was proposed as a submersible axial propeller type pump station pumping directly to the Cowichan River through the dyke. The flood pump stations provided flood protection for the McKinstry Road and Fish Gut slough catchment only.

A third option was proposed. This option comprises the sole use of the Marchmont Pump Station with a gravity connection from the Lee Street section of Fish Gut Alley slough along Lakes Road. This option would allow the slough to be used as a storage facility for different conditions to reduce the pumping requirements - assuming the connection would provide sufficient capacity for the two way flow of water into and out of the slough. This option would also allow for construction in the slough to be minimized, and the Marchmont Pump Station to be upgraded to differing conditions relative to the storage provided.

1.1 Background

In November 2009, the Lee Street area of the City of Duncan experienced considerable flooding due to a combination of heavy rainfall and sustained high water on the Cowichan River. In a subsequent study nhc recommended pumping to mitigate future flooding, and two potential locations were identified. The site options for the McKinstry Road or Lee Street Pump Station and Floodbox are located on the north bank of the Cowichan River at the south-east City of Duncan boundary in an oxbow slough identified as Fish Gut Creek. The tributary area to the Lee Street site is 19.7 ha including the 4.3 ha of slough. The McKinstry Road or Lee Flood Pump Station is to be a new facility. In a memorandum by Northwest Hydraulics Consultants (nhc), dated July 26, 2010, nhc recommended an Archimedes Screw pump for the Lee Street installation to meet Fisheries concerns, and propeller type pumps for the McKinstry Road Pump Station (due to lower fisheries concerns at this location).

In the report, nhc recommended a pump capacity of 0.4 to 0.6 m3/s with a minimum of two screw pumps for a 200 year event. The second pump may be installed in the future depending on funding and need. The 0.6 m3/s pump capacity represents a drainage capacity of 3 m3/s – km2 for the 19.7 ha of drainage catchment, which is suitable for an urban drainage catchment with minimal or no storage in Duncan.

1.2 Scope

The work is part of Task A of the Pre-design of the flood pump station. The objective of the Pre-design is to provide feasibility and preliminary design, which establishes the pump station size, appropriate siting and Class B cost estimate.

The work includes initial discussion with the approving agencies and preliminary investigation of the geology of the proposed sites.

The technical memorandum describes the design objectives and constraints as well as permitting needs. The flood pump solution is to meet a triple bottom line business case to secure the best environmental, societal and cost effective solution.

1.3 Limitations

Study limitations and assumptions include the following:

1. The nhc dyke upgrade is assumed to be in place. 2. The District of North Cowichan will agree to provide similar drainage protection to the floodplain north of City of Duncan limits to the new dyke. 3. Soil data and hydrological data are obtained through reference information only and do not reflect specific site examination. 4. No redundancy is provided. 5. Environmental information is adequate for the the review of the three sites but further assessment may be needed depending on the selection.

1.4 Method of Survey

The pre-design work was undertaken in conjunction with the Opus DK City Wide Storm Drainage Planning Study – currently in progress. The 2010 nhc Lower Cowichan/Koksilah River Integrated Flood Management Plan Final Report was also reviewed. These reports were used as principal references for design criteria. The nhc July 2010 Lee Street Flood Mitigation memorandum was also used for data.

Madrone Environmental provided agency liaison and environmental information. Levelton Associates provided geotechnical assistance. The two reports are attached as appendices.

POSSIBLE FUTURE PS

HOWARD STREET PS

COLLEGE STREET BEVALY PS LEGEND

DISTRICT OF NORTH LAKES PS

TO CITY OF NORTH COWICHAN COWICHAN DRAINAGE SYSTEM PARK TRUNK ROAD TCH CENTENNIAL

SLIDE GATE CITY OF DUNCAN JUB LAGOON

MARCHMONT PUMP MARCHMONT ROAD STATION (2 PUMPS)

',6&+$5*(

)/22' I.R. NO.1 GATES

CITY OF DUNCAN FLOOD PLAIN COWICHAN RIVER LEE STREET SLOUGH SECTION DRAINAGE CATCHMENT BOUNDARY OF FISHGUT ALLEY Page

SCALE 1:10,000 16 HATCHERY DISCHARGE of 64

210 - 889 Harbourside Drive North Vancouver, BC Vancouver Office V7P 3S1, CANADA +1 604 9904800 FIGURE 1-1 Page 17 of 64

2.0 EXISTING CONDITIONS

2.1 Drainage Overview of City of Duncan

The City of Duncan, east of the railway tracks, contains two drainage catchment areas:

McKinstry Road and the Lee Street section of Fish Gut Alley slough which make up 19.7 ha. Trunk Road Catchment Area which makes up 72.3 ha.

The McKinstry Road/Lee Street section of Fish Gut Alley slough drains by gravity into the Cowichan River. When the Cowichan River floods, the flap gates close and the water level in the slough builds up until river levels drop below the level in the slough, and the flap gates open.

The balance of the floodplain drainage (referenced as the Trunk Road catchment) drains by gravity to Somenos Creek during summer and early fall. However, once water levels in Somenos Creek rise, the slide gate on the outlet is manually closed, and all drainage from this catchment flows to the Marchmont Pump Station and is pumped into Fish Gut Alley Creek, just upstream of the confluence with the Cowichan River.

The area is low-lying, and the overall catchment area extends north from Trunk Road into the District of North Cowichan. The low lying flood plain area below elevation 10 to 11 m GSC within the City boundary is 92 ha. The total flood plain area below elevation 10 to 11 m, including the District of North Cowichan floodplain, is 225 ha. The flood plain area is illustrated on Figure 1-1.

The nhc Memorandum Lee Street Flood Mitigation, July 26, 2010 reports that the Fish Gut Alley slough drainage catchment consists of about 15.4 ha of urban developed land and an additional 4.3 ha of slough. The slough is estimated to have about 4300 m3 of storage capacity per 100 mm rise above 8.2 m. Available storage volume below this elevation would be less. The slough could be used as a forebay or storage for flood water. Design would need to assume a combination of storage and flood pumping without gravity drainage during the design condition of a high water stage in the Cowichan River and maximum excess runoff conditions.

Assumptions on the drainage design include:

a) the existence of the new dykes on the Cowichan River and Lakes Road; b) the separation of drainage responsibility between North Cowichan and Duncan at a divide approximately at Trunk Road; and c) 100 year return excess rainfall for design combined with a daily 25 mm of groundwater discharge over the floodplain.

2.2 District of North Cowichan Pump Stations

The lowland drainage for North Cowichan is discharged to the Somenos Creek through three stormwater pump stations (SWPS) identified as Howard Avenue, Lakes Road and Beverly. These are shown on Figure 1-1. The catchment size of the dewered area tributary to the pump stations is 50 ha. For comparison, the capacity of each station and overall unit area drainage capacity for the 133 ha are as follows:

Station Pumps Capacity Howard Ave SWPS 2 x 2500 GPM 0.32 m3/s Lakes Road SWPS 2 x 4000 GPM; 0.50 m3/s Beverly SWPS 1 x 2500 GPM and 1 x 1500 GPM 0.25 m3/s Total capacity 1.1 m3/s Unit Area Capacity, 50 ha 2.2 m3/s/km2 (7.9 mm/hr) Unit Area Capacity, 133 ha 0.83 m3/s/km2 (3.0 mm/hr)

* Beverley SWPS operated when water levels exceed 6 m and tide gates close.

The unit area capacity represents a return storm as determined from Table 4-1. The 50 ha cartchment would be flooded for 3 to 6 hours – 10 year; 4 to 8 hours – 25 years, or 6 to 12 hours – 100 year, assuming no storage. The larger 133 ha catchment would be flooded for more than 1 to 2 days at the pump capacity available.

2.3 Marchmont Flood Pump Station

The existing Marchmont Flood Pump Station was constructed as a combined sanitary and flood pump station around 1991. The two wet wells are separated. Storm water is pumped through the dyke into an oxbow identified as Fish Gut Alley Creek which flows east to the Cowichan River.

The pump station currently is supplied with 3 phase, 600V but this is stepped down to 460V for the drainage pumps. A diesel powered standby generator is rated at 190 kW and 238 kVa. The transfer switch is rated at 800 A and 600 V. This supplies back up power for the 3 sanitary and 2 drainage pumps. The drainage side of the pump station is configured for two small pumps (both of which are installed) and two large pumps (anticipated future installation). Two 30 Hp, 1175 rpm GE motors drive the two small Aurora mixed flow or propeller pumps of 450 mm diameter. Space in the discharge header has been provided for two 600 mm diameter pumps. It is not known what the required suction head for the pump

is. However, the horizontal geometry for the pump separation and installation dimensions exceed minimum National Hydraulic Standards criteria.

The installed drainage pumps are rated for a maximum flow of 6500 USGPM (0.41 m3/s) each. During normal rainfall events, the lead pump is reported to operate almost continuously, with the second starting occasionally. (In high rainfall flood conditions both pumps are assumed to run continuously.) Pump operation records from October 2010 to March 2011 indicate little to no pumping during dry weather suggesting little groundwater base inflow.

The across the line starters are powered through 480V, 225A, 3 phase, 60 Hz power distribution panel. The pumps collect drainage from an upstream sewered collection system and discharges through a 900 mm CMP low pressure forcemain and a 1200 mm concretegravity drainage pipe through the dyke to Fish Gut Alley slough and the Cowichan River. The gravity portion of the discharge pipe to the slough is reported to have a build-up of sediments and debris causing discharge impedance. The CMP section of pipe is not sealed at joints and leaks during pump discharge.

The two pumps are currently estimated to be draining about 73 ha of tributary sewered area. This means that the drainage capacity of the pump station is about 1.09 m3/s-km2 with both pumps running. This equates to about 4 mm/hr of rainfall in the catchment. Figure 2-1 illustrates the cumulative run-off volume of the 5–year return storm compared against the flow capacity of the current pumps as well as pump capacities for 2 and 3 times the current capacity, shown as volumes pumped through a 24 hour period. The current pumps (identified as the squares and Pump 1.09 m3/s-km2 curve) do not protect the catchment for a 5-year return storm during high water conditions on Somenos Creek. About 10,000 m3 of system storage is required to meet the 5 year protection as shown in the difference between the (diamond) Mass Flow and (square) Pump 1.09 m3/s-km2 curve lines. Higher pump capacities (cross hair and triangle curves) are shown for comparison as Pump 3 m3/s-km2 and Pump 2 m3/s-km2.

FIGURE 2-1 – 5 YEAR MASS CURVES DRAINAGE FOR EXISTING MARCHMONT PUMP CAPACITIES OF 1, 2 and 3 m3/s per km2

2.4 Groundwater Infiltration

In the study area, the groundwater depth is 0 to 4.5m and conductivity is reported as 820 m/d, (Geological Survey of Canada, (2010), File 6168, Technical Summary of Intrinsic Vulnerability Mapping Methods in the Regional Districts of Nanaimo and Cowichan Valley). The gradient in the flood plain is about 0.002 m/m from the nhc Sept 2009 floodplain study. For the City of Duncan floodplain study area of 92 ha and a 1000m of flow path width, this represents a daily groundwater flow of about 1,700 m3/m-d, (2 mm /day per m of water depth) and 0.02 m3/s/km2 per meter of water depth. For 4 m of water depth this would be 0.086 m3/s/km2 . The groundwater infiltration rate is observed to be less than the current single pump capacity of 0.59 m3/s/km2, (6500 USGPM or 0.41 m3/s).

A conservative estimate for pump design of 25 mm or about 1 mm/hr is assumed for the base flow for the pumping for wet seasonal conditions. (This is 25% of the current pump capacity.)

2.5 Fish Gut Alley Slough Storage

The nhc (2010) July 26, Memorandum, Lee Street Flood Mitigation, Conceptual Design of Fish-Gut Alley and McKinstry Road Pump Stations, provides design details for consideration of new drainage pumps for the Fish-Gut drainage of about 15.4 ha of Urban and park land use upstream of the slough of which the McKinstry urban and road drainage is 11 ha.

The slough storage capacity is provided in the nhc memorandum (2010) as follows:

Elevation, m GSC Storage Volume, m3 8.2 29,017 8.4 36,874 8.5 41,160 8.7 49,7332 8.9 58,304 9.1 66,876 9.2 71,162

The slough water surface elevation is to be maintained below elevation 8.5 m. Slough depth at the eastern edge would be required to support an inlet for a screw pump at 6.5 m. The operation of a pump at the western edge is assumed to be above 8.0 m so as not to affect water levels.

The lowest yard level adjacent to the Fish Gut Alley Slough (along the Lee Street) is about 8.9 m, although this was not confirmed and yard elevations may be lower. It may be necessary to maintain a maximum flood level of below this, (a suggested maximum storage level for pre-design purposes is 8.5 m) m in the Lee Street section of the Lee Street section of Fish Gut Alley slough to avoid any risk of upflow seepage into low-lying residential yards. If storage is provided for the lowland protection, the Marchmont sump high water level will dictate maximum levels. This will be below 7 m so the slough high level is not an issue.

Figure 2-2 illustrates a profile through Lee Street section of Fish Gut Alley slough, extending to the Marchmont Pump Station. The hydraulic profile of the Marchmont pump station and relative water levels of the slough are illustrated. During normal flow periods, the water level is typically about 6.7 to 6.8 m at the lower end rising to 7.3 to 7.4 at the upper end. The rise is the result of a beaver dam near the lower end. The current dyke elevations, the 1998, 200-year dyke design elevation and the nhc proposed dyke elevations are also illustrated on Figure 2-2.

2.6 Environmental Goals and Constraints

The environmental report by Madrone Environmental Services is attached as Appendix 1 to the memorandum and compares the three site options for impact on the habitat and environment. The report identifies related considerations, schedules and application requirements.

The Madrone report suggests the following requirements for the options selection:

Agency requirement for work in the Lee Street section of Fish Gut Alley slough behind the dyke - The slough represents perennially accessible habitat for fish. Work schedules will be required to be held within the accepted „instream work window‟ of

July 1 to September 15. Fish salvage operations may be needed and construction activities would need to be staged to avoid critical impact on the fish life stages. Mitigation could include proper storage and handling of deleterious material and protection of the habitat through best management practices. A sediment and erosion control plan may be needed. An environmental management plan (EMP) would be needed to address the construction activities.

Agency requirement for work out side of the dyke in the Cowichan River water edge - Work on the water side of the Cowichan River would require similar attention to activities as within the Lee Street section of the Fish Gut Alley slough.

Limits to the construction period – July 1 to September 15 weather dependent?

Water level changes that could take place in the slough – Because the storage requirement would be below elevation 7 m, the existing beaver dam effectively reduces the area and volume of storage to a small pond near the fish hatchery. To avoid loss of the beaver dam and potential water draw-downs that could create stranding of fish in marginal areas and to minimize impact on the natural habitat, the storage available is restricted to the current use of the slough for containing runoff from McKinstry Road and the current pond. For the selected site, applications will need to be forwarded to Fisheries and Oceans Canada (DFO) and the Ministry of Environment (MoE). The applications will need to identify descriptions of the construction method, engineering drawings of the installation, descriptions of the habitat affected, a list of potential impacts to fish and fish habitat and the EMP specific environmental requirements will need to be provided and agency submissions provided as needed.)

Lower End of FishGut Creek and Slough Showing Beaver Dam

2.7 Geology of the Sites

Levelton Associates provides the following design constraints for preliminary selection of the pump station site:

Fish-Gut Alley Creek /Lee Road Dyke construction and seepage potential Dyke penetration design criteria for Cowichan and Lee Road Dykes Soil conditions likely to be found at a site in Fish-Gut Alley Creek and at the foot of McKinstry Road and at the Marchmont Pump Station Soil conditions likely to be found for a large diameter pipe from Marchmont to Fish- Gut Alley Creek along the dyke Water management for construction, and groundwater flows likely to be experienced for base flow conditions Cost estimate provisions for excavations for three options: 1) Lee Road Screw Pump in the slough; 2) McKinstry Propeller Pump near foot of McKinstry Road, and 3) expansion to Marchmont Pump Station and construction of 1200mm +/- diameter connection from the pump station to the slough.

No major issues were noted, and the additional soils investigation of the selected site will be carried out as needed. The Levelton report is attached as Appendix 2.

LEE STREET SECTION OF FISHGUT ALLEY CREEK Page 24 of 64

210 - 889 Harbourside Drive North Vancouver, BC Vancouver Office V7P 3S1, CANADA +1 604 9904800 FIGURE 2- 2 Page 25 of 64

3.0 DEVELOPMENT OF DRAINAGE PUMPING OPTIONS

In their 2010 report “Conceptual Design of Fish Gut Alley and McKinstry Road Pump Stations”, nhc identified two locations for a pump station to prevent flooding of the Fish Gut Alley Slough. The options were to locate the pump station at the outlet from the Slough into the Cowichan River, or to reduce inflows to the slough by locating the pump station at McKinstry Road and pumping directly to the Cowichan River. The pump capacity was determined to be 0.6 m3/s and two pumps were required to provide 100% redundancy (this pump capacity represents a drainage capacity of 3.3 m3/s/km2 for the 19.7 ha catchment). Both options have been carried forward for further review. (The second option for McKinstry Road includes an alternative to pump to the Marchmont Flood Pump Station in lieu of the Cowichan River).

The drainage catchment contributing to Fish Gut Alley slough is 19.7 ha (nhc report, 2010), which is approximately 21% of the total catchment area.

Since Opus DK is also carrying out the City Wide Storm Drainage Planning Study, a third option has been developed. The option comprises extending an overflow drainage connection from the Fish Gut Alley slough to the existing Marchmont Pump Station, and upgrading this pump station. This option offers some advantages over providing a new pumping station at Lee Street section of Fish Gut Alley slough:

It addressess a shortfall in capacity at the Marchmont Pump Station and benefits the entire catchment area; It reduces the impact of construction on the Lee Street section of Fish Gut Alley; and It allows for some of the storage capacity of the Lee Street section of Fish Gut Alley slough to be used to reduce the peak flows out of the slough during major storms.

The pump station options carried forward for evaluation are:

Option 1 – Locate the pump station at the outlet from Fish Gut Alley Slough, with discharge through the dyke to the Cowichan River per the nhc report. In their report, nhc recommended a concrete trough screw pump. This option accommodates the 19.7 ha catchment area.

Lee Street Flood Pump Site – Looking South across from the Fish Hatchery on east side of slough

Option 2 – Locate the pump station at McKinstry Road with discharge through the dyke to the Cowichan River for the nhc report. This pump station would be an axial flow propeller style pump. This option accommodates the 15.2 ha catchment contributing to Fish Gut Alley Slough. It includes pumping to the Cowichan River, Option 2a, or pumping to Marchmont Pump Station, Option 2b.

McKinstry Road Flood Pump Possible Site at Upper End of FishGut Alley Creek and Slough

Option 3 – Construct an overflow at the east limits of Fish Gut Alley Slough with gravity flow to the Marchmont Pump Station and upgrade the pump station to handle the additional flows. Discharge would be through the existing forcemain into Fish Gut Alley Creek just upstream from the confluence of Fish Gut Creek and the Cowichan River. This option could be expanded to benefit the entire 92 ha catchment area. Two scenarios for pump size are investigated; one with storage for the 92 ha and one without.

Marchmont Flood Pump Station and Sanitary Pump Station Structure and Genset

Marchmont Flood Pump Station Dicharge Header showing two 450 mm active and two 600 mm future connections. At the City Works Yard.

4.0 DESIGN CRITERIA

4.1 Fish Gut Alley Slough Catchment Area

The catchment area for this slough was modelled by nhc in the 2010 report. Based on the run-off modelling and the slough storage, nhc recommended a pumping capacity of 0.6 m3/s to maintain the slough water level at or under 8.5 m during the 200 year five day storm.

Pump station sizing for the Fish Gut Alley Slough was set at 0.6 m3/s for Options 1 and 2.

4.2 Hydrologic and Hydraulic Criteria

In order to evaluate Option 3, it is necessary to model run-off from the entire 92 ha catchment area, and determine the pump station sizing based on a design storm event.

Opus DK Technical Memorandum No 2 of the City Wide Storm Drainage Planning Study (February 2011), provides the data base used for the pump station sizing and intensity duration frequency curves.

Table 1 provides the data for modelling the pump station sizing. The data provide 10, 25 and 100 year frequency storms. The total volumes over the period of the storm represent the total excess volume of flood water to be cleared by the pumps or drainage discharge floodgates during the period of rainfall. Unlike the slough modelling, the rainfall period investigated is over 24 hours since the land use is urban and drainage will normally need to be cleared within this time frame unless sufficient safe storage is available.

The Soil Conservation Service USDA criteria are used to determine abstraction data for estimation of the excess runoff volumes. (Ref., Urban Hydrology for Small Watersheds, Technical Release No 55, Engineering Division Soil Conservation Service, U.S. Department of Agriculture, January 1975.)

The rainfall abstraction information is identified in Table 4-1.

TABLE 4-1 MASS DIAGRAM DATA FOR EXCESS RAINFALL Summer Winter CN CN Abstraction, mm Ia = 0.2.S mm CN 78 99 Runoff, mm Q= (P-Ia)^2/(P+0.8.S) mm AMC II III Soil storage, mm S= (1000/CN-10)x 25.4 mm

Coef CN Coef CN 10 yr 25 yr 100 yr 100 yr 78 99 Total Time Rainfall Rainfall Rainfall Mass Mass Ground Mass I I I P Summer Winter Water Winter Hrs Intensity Intensity Intensity Volume Runoff Q Runoff Q 25 Runoff GW mm/hr mm/hr mm/hr mm mm mm mm mm

0 0 0 0 0 0 0 0 0.00 0.08 50.00 60.00 80.00 6.67 0.00 4.34 0.09 4.43 0.17 38.00 43.00 59.00 9.83 0.00 7.31 0.17 7.48 0.25 30.00 36.00 50.00 12.50 0.00 9.87 0.26 10.13 0.50 22.00 27.00 35.00 17.50 0.13 14.76 0.52 15.28 1.00 13.00 15.00 17.00 17.00 0.10 14.27 1.04 15.31 2.00 9.00 10.20 12.00 24.00 1.15 21.17 2.08 23.25 3.00 8.00 9.00 10.00 30.00 2.81 27.13 3.13 30.26 4.00 7.00 8.00 9.00 36.00 5.03 33.09 4.17 37.26 6.00 6.00 6.80 7.80 46.80 10.13 43.86 6.25 50.11 12.00 4.40 5.00 6.00 72.00 25.72 69.01 12.5 81.51 24.00 3.40 3.80 4.40 105.60 51.13 102.58 25 127.58

Select from 1, 2 or 3 column for 10yr, 25 yr or 100 yr return rainfall Rainfall from AES North Cowichan BC 22 years 1982 - 2005

Table 4-1 identifies a continuous groundwater component of 25 mm/day that is added to the collection and would be pumped by small duty pumps during none storm events and combined and pumped by the flood pumps during excess rainfall events.

The table compares 10, 25 or 100 year return storms intensities. The 100 year condition is illustrated in the table for total volume. Abstractions conditions for summer (CN-78) and winter (CN=99) are also compared to illustrate likely pumping requirements.

4.3 Level of Protection using Dykes

In floodplain environments undergoing urban densification, we have established from our records of British Columbia floodplain previous drainage projects, that the drainage design should combine both minor and major protection for a one in 25-year return storm. Floodplain assessments establish the balance between flood loss, and life cycle cost for

flood protection works. Where upland protection is needed, without the expense of dyke and internal pump stations, a typical minor event for nuisance flood protection is about a 5 to 10 year return storm. In high valued areas, a 25 or 50 year return storm events may be required. Major flood protection for 100 year or 200 year return storm event are typically handled through overland surface drainage, unless an area is isolated and special circumstances requiring other forms of drainage are needed, such as large storm drainage pipelines or diversion facilities to handle the excess major flows.

In an enclosed or protected floodplain however, the minor and major flows are treated the same since all drainage is trapped and must be removed from the flood protected area, usually by floodboxes and pumping facilities. Further, floodplain drainage areas should not rely on one outlet. They also are typically interconnected to provide safety should one system be inoperative. This lowers flood risk although service protection may be reduced.

Costs of improvements such as dyke protection, pumping station and floodboxes are added to costs of typical urban drainage infrastructure to increase the unit service area costs for floodplain protection. The urban drainage management of floodplains is restricted to internal drainage issues, and the costs of flooding are related to nuisance costs and flood damage. Loss of life is related to the flood protection from the river and is not included in a risk-cost evaluation for floodplain protection infrastructure per se. By recognizing that minor and major drainage infrastructure requires the same flood protection in a floodplain setting, a cost analysis of floodloss to flood protection shows that a 25-year or higher return period design storm is justified for the minor-major drainage infrastructure. The infrastructure has typically taken the form of large ditches, large floodbox forebays, pumps and floodboxes. With time the ditches are replaced with large culverts or pipelines, structures are built above the flood level, and pumping capacities are increased to compensate for loss of detention storage within the catchment area.

Minor storm sewer lines and ditches with a 5 to 10 year return period design storm capacity may still be used in the flood plain catchment areas, as long as other conveyance to the discharge (such as canals or large ditches) meets the minimum 25 year protection.

Stormwater drainage systems for the floodplain catchment area should provide for the 25 year return period storm event or greater, but will also need to provide for coincident high river stages and the impact of “back door” flow from the Somenos River backwater and high ground water. Capacity to discharge at least the 25 year return period storm event and coincident high groundwater discharge will eventually be needed. The high water is assumed to be highwater conditions in the Cowichan River that occur in high precipitation events The City of Duncan has elected to use a 100-year return period for the flood pumping. (This is the highest protection available from AES rainfall records for the site.)

4.4 Hydraulic Criteria

The Hydraulic Standards Institute recommendations for the design of influent pump chambers and pump separation are noted in the following:

Dimension Wet well propeller mixed flow pumps D Pump suction bell diameter D/2 Distance to side wall from centreline 2D Distance separating pump suctions at centreline B Back wall distance from centre of bell to back wall; 0.75 D, max; 0.6 D min hc Bell distance to floor, 0.5D, max; 0.33D min Hs Submergence above impeller eye; per pump specification Hm Maximum wet well level L Approach apron length to centre of suction bell, 6D Entrance Velocity to suction a) 0 to 4.5 m, 0.6 to 0.75 m/s inlet b) To 15 m, 0,76 to 1.2 m/s

5.0 DRAINAGE ANALYSIS

As illustrated on Figure 1-1, the overall floodplain drainage catchment is 225 ha of which 92 ha is within the City of Duncan drainage. During high river stages when gravity drainage is not available, the pumped drainage can either be combined into one flood pump facility or separated into two or more. In either case, the drainage collection must be capable of conveying the collected surface water to the pump facilities and the drainage pump capacity must be sufficient to discharge all collected water to the outside of the dyked areas.

The District of North Cowichan will need to provide capacity for133 ha. A separation of the two drainage areas must then be maintained at a divide approximately located at Trunk Road. This leaves the City of Duncan to provide pumping capacity through one or more flood pumps for the 92 ha, (which includes the Fish Gut Alley slough catchment area).

Surface water storage can be used to reduce the design capacity of the pumps. Fish-Gut Alley slough provides a storage reservoir that may be used for some storage as long as the fisheries resource is protected and flood protection is provided to properties adjacent to the Lee Street dyke.

In the following analysis, the pumping requirements to alleviate flooding for the entire 92 ha catchment are assessed, and the analysis for the Fish Gut Alley slough is also reassessed to take the storage available in the slough into account.

5.1 Overview of Drainage Conditions

Figure 5-1 provides an illustration of the existing and upgraded drainage system capacities (based on the 92 ha catchment) for the 100-year return storm. Runoff accumulation for the 100-year return storm is shown as the curved line. The mass runoff accumulation identifies the total volume of runoff that is expected to occur during a 100- year return rainfall for all duration conditions including the allowance for groundwater infiltration. The straight lines reflect the capacity to remove the drainage water for three different pumping capacity conditions: 0.89 m3/s-km2 (the existing pump capacity), 1.5 m3/s-km2, and 3.0 m3/s-km2. (With both pumps running, the current Marchmont Flood Pump Station capacity for the 92 ha of catchment is of 0.89 m3/s-km2.) To make this pump station effective for the 100-year protection, a pump capacity increase is needed and with either:

a) a large storage volume and a minor increase in pump capacity, or b) a small volume of storage and a significant increase in pumping capacity.

FIGURE 5-1 100 YEAR MASS CURVES DRAINAGE FOR MARCHMONT PUMP CAPACITIES OF 0.89, 1.5 and 3 m3/s per km2

As illustrated in Figure 5-1, the existing pumps as shown by the squares cannot pump the 100-yr return storm as illustrated by the Mass Runoff (shown as diamonds), without substantial storage..

The storage volume needs are shown on Figure 5-2 for the three pump capacity scenarios. Storage volumes needed for the existing pump capacity (0.89 m3/s/km2) are not illustrated but would exceed 50,000 m3.

FIGURE 5-2 100 YEAR STORAGE REQUIREMENTS FOR MARCHMONT PUMP CAPACITY OF 0.89, 1.5 and 3 m3/s per km2

Table 5-1 provides a summary of the storage volume and pump requirements relative to the risk of flood based on assured pump capacity.

TABLE 5-1 FLOOD DURATION, STORAGE REQUIREMENTS AND PUMP CAPACITY FOR 1 IN 100 YEAR EVENT Pump Storage Case 1 (Existing) Case 2 Case 3 Condition Storage Pump Storage Pump Storage Pump Parameters Need Capacity Need Capacity Need Capacity Rating HIGHEST LEAST HIGH MODEST LEAST HIGHEST >50,000 0.89 1.5 3.0 17,000 m3 9,000 m3 m3 m3/s/km2 m3/s/km2 m3/s/km2 Maximum, hrs > 24 - 10 - 0.5 - Time of >72 - >24 - 3 - storage, hrs Flood Risk HIGH MODERATE LOW

(1) Model generated volumes including pipe volume, dry storage and wet storage (approximate values shown).

Case 1 – Maintain Existing Pumping Capacity

The current pump capacity is about 0.89 m3/s per km2 for the 92 ha catchment area. As shown this capacity is insufficient to protect the area from coincident high groundwater and a 100 year storm. If storage in excess of 50,000 m3 were provided, the pumps would be sufficient to protect the urban catchment. This represents about >9 m elevation of live storage in the Fish-Gut Alley slough. This amount of live storage is not practically available, so increased pump capacity is required.

Case 2 – Increase Pumping with High Storage Capacity

A Pump capacity increase to at least 1.5 m3/s per km2 for each drainage catchment is preferred to reduce the flood from the 100-year design storm to less than 24 hours of nuisance flooding or equivalent storage requirement. For the 92 ha catchment, the pump capacity required to provide this drainage capacity is 1.38 m3/s. The existing two pumps provide about 0.82 m3/s, leaving additional pumping capacity of about 0.56 m3/s required. At least 17,000 m3 of live detention storage is required. This represents about 0.5 - 0.6 m of depth change in the Fish-Gut Alley slough over its full length during a 100-year event.

Case 3 – Maximize Pump Capacity with Limited Storage

At least 3 m3/s per km2 drainage capacity would be needed to meet a 30 minute allowable nuisance flood design. This would be desirable if little to no detention storage is available. For the 92 ha catchment, the pump capacity required to provide this drainage capacity is 2.76 m3/s The existing two pumps provide about 0.82 m3/s, leaving an additional capacity of about 1.94 m3/s required. About 9,000 m3 of detention storage is required. This represents about 0.25 - 0.3 m of depth change in the Fish-Gut Alley slough; over its full length, during a 100-year event.

5.2 McKinstry Road and Lee Street Flood Protection

The McKinstry Road Catchment is 15.4 ha and with the slough of 4.3 ha, the total catchment area is 19.7 ha. (This total is assumed to be the tributary catchment for either of the Lee Street or McKinstry Road sites.) Figure 5-3 illustrates that the pumping requirements for no storage - at 3 m3/s per km2 - is about 0.59 m3/s. If storage is available, the rate of discharge can be reduced. Figure 5-3 illustrates that the storage requirements for pump capacities of 0.3 and 0.2 m3/s (representing drainage capacities of 1.5 and 1 m3/s per km2 respectively).

If the McKinstry Road drainage is left to discharge to the slough and pumped from the slough storage, pump capacities can be significantly reduced.

FIGURE 5-3 100 YEAR MASS CURVES DRAINAGE FOR PUMP CAPACITIES OF 1, 1.5 and 3 m3/s per km2 McMINSTRY ROAD AND FISH GUT ALLEY SLOUGH

TABLE 5-2 McKINSTRY ROAD- LEE STREET FLOOD DURATION, STORAGE REQUIREMENTS AND PUMP CAPACITY FOR 1 IN 100 YEAR EVENT Pump Storage McKinstry Lee 1 McKinstry Lee 2 McKinstry Lee 3 Condition Storage Pump Storage Pump Storage Pump Parameters Need Capacity Need Capacity Need Capacity Rating HIGHEST LEAST HIGH MODEST LEAST HIGHEST 1.0 1.5 3.0 8,500 m3 3,500 m3 2,000 m3 m3/s/km2 m3/s/km2 m3/s/km2 Maximum, hrs 24 - 10 - 0.5 - Time of >72 - >24 - 3 - storage, hrs

(1) Model generated volumes including pipe volume, dry storage and wet storage (approximate values shown).

Table 5-2 compares the three conditions for the Lee Street section of the Fish Gut Alley slough catchment. If the slough can be used for storage the pump capacity can be reduced. If the McKinstry Road drainage is allowed to pass through the slough and discharge to the Lee Street or Marchmont Flood Pump Stations, the maximum available

storage could be assumed and the design flow to the Lee Street and Marchmont Flood Pump Station can be reduced to be 0.2 m3/s for a 100 year storm protection (Case 1 – 1.0 m3/s-km2).

5.3 City Wide Storm Drainage Analysis

The City Wide Storm Drainage analysis considered the Fish Gut Alley and Marchmont Drainage (Trunk) catchments separately. Return storm runoff was calculated for 10, 25 and 100 year events and are compared in Table 5-3.

TABLE 5-3 CRITICAL STORM DURATIONS AND PEAK FLOWS Storm Storm Drainage Catchment Peak Flow Frequency Duration Trunk Road 10 year 6 hour 2.16 m3/s 25 year 6 hour 2.26 m3/s 100 year 1 hour 2.3 m3/s1 Fish Gut Alley Lee Street 10 year 2 hour 0.42 m3/s Section 25 year 2 hour 0.49 m3/s 100 year 1 hour 0.42 m3/s1

Note 1: The concentration time for the basin is larger and therefore flow shown is less than actual peak.

If the storage capacity of Lee Street section of the Fish Gut Alley slough can be utilized to attenuate the peak run-off from this catchment, the peak design flow from the slough to the pump station can be limited to 0.2 m3/s. This would reduce the design peak pumping requirements at the Marchmont Flood Pump Station to approximately 2.5 m3/s for the 100 year return storm.

The flows correlated sufficiently well with the mass diagram flow determination to confirm the pump and storage volume determination.

6.0 FLOOD PUMP CAPACITY SCENARIO REVIEW

The flood pump capacity for Fish Gut Alley slough and catchment area – 19.7 ha - has been determined by nhc to be 0.6 m3/s, but, as illustrated in Section 5, this capacity could be reduced to 0.2 m3/s if storage of 8,500 m3 in the slough can be utilized. This represents about 0.2 m water depth in the slough.

For the entire catchment area of 92 ha, the pump capacity recommendations are strongly predicated on the assumptions of the hydrologic analysis and in particular the need to focus only on addressing stormwater issues in the flood plain area for the City of Duncan. a) Scenario 1 Minimum Capacity of Pumping and Maximum Storage: The assumptions used in this study conclude that the minimum pump capacity for a 1 in 100 year rainfall event for the entire 92 ha catchment area will depend on the storage available in the Fish Gut Creek slough Lee Street section for all pump station location options. If the McKinstry Road drainage combines with the slough, the storage is sufficient to allow a pump capacity of 0.2 m3/s for the 100 year return storm.

Pump capacity to at least 1.5 m3/s-km2 will be needed for Marchmont Flood Pump station (this represents a pump capacity of 1.38 m3/s); this requires an active storage of 17,000 m3. For the existing capacity of 0.82 m3/s and a total capacity requirement of 1.38 m3/s, the required increase in capacity is 0.56 m3/s.

Scenario 1 requires that Fish Gut Alley slough provide storage for the 92 ha of catchment and that Marchmont Flood pumps be connected to the slough for a flow of about 1 m3/s. The selection of the low pumping discharge rate is predicated on the maximum storage use for the Lee Street section of Fish Gut Alley slough. b) Scenario 2 Maximum Capacity of Pumping and Minimum Storage: The large storage volume in Scenario 1 may not be available for Option 3, Marchmont Flood Pump Station, since the hydraulic profile of the slough is interrupted by the beaver dam and existing operating elevations above 6.7 m would not easily allow inflow to the slough from the collection area. Since the station is therefore, not capable of meeting the flood protection requirements for the City, an increase in pumping capacity is needed. Without storage, the design pumping should be about 3 m3/s/km2 or greater (this represents a pump capacity of 2.82 m3/s). This could be provided by about 0.82 m3/s for the existing Marchmont Flood Pumps and about 2 m3/s for the new pumping capacity either added to Marchmont or in Fish Gut Alley.

7.0 FLOOD PUMP LOCATION CONSIDERATIONS

7.1 Option Comparison

Table 7-1 provides a comparison of the advantages and disadvantages of the pump station locations for the three options.

TABLE 7-1 COMPARISON OF OPTIONS Options Advantages Disadvantages 1 – Lee Street Can be used in conjunction with Does not in itself provide 100 year Flood Pumps Option 3 to provide protection flood protection for the 92 ha of for the 92 ha of flood plain. flood plain Can use the storage offered by Requires dyke crossing and may the slough to reduce pump rates impact dyke construction Protects fishery with screw pump Requires new access and water management permit for affecting fish bearing stream and construction of works. 2 – McKinstry Can be used in conjunction with Does not in itself provide 100 year Flood Pump Option 3 to provide protection flood protection for the 92 ha of to river for the 92 ha of flood plain. flood plain Options 2a Can use the storage offered by Requires dyke crossing and may and 2b the slough to reduce pump rates impact dyke construction Avoids use of slough for urban May require new access and water drainage discharge management permit for affecting fish bearing stream and construction of works if constructed in slough. High risk that archaeological investigation could impact the project. This may increase if Option 2b were used since it will require more open excavation for pipeline. 3 – Provides full protection for the Requires a large volume of Marchmont 92 ha of flood plain for 100 year storage in the Lee Road section of Flood Pump return flood protection the Fish Gut Alley slough that Scenario 1 may not be available. Requires improvements to pumping capacity

TABLE 7-1 (cont’d.) COMPARISON OF OPTIONS Options Advantages Disadvantages Upgrades existing pump station Impacts slough environment and improves safety for operations; allows new electrical upgrade to 600 V Avoids new dyke crossing Avoids need for Options 1 or 2. A large connection to allow up to 1 m3/s to flow in and out of the slough will be needed and protection from fish entry. 3 – Provides full protection for the Requires larger capacity pumps Marchmont 92 ha of flood plain for 100 year and structural provisions for Flood Pump return flood protection hydraulic improvements. Scenario 2 Upgrades existing pump station . and improves safety for operations; allows new electrical upgrade to 600 V Avoids new dyke crossing Minimizes storage requirements of slough. Connection of the slough and The connection will require McKinstry drainage to the protection for fish entry. Marchmont Flood pump station can be undertaken along Lakes Road to an existing pipe Avoids need for Options 1 or 2.

7.2 Cost Comparisons

Cost estimates have been prepared for Options 1, 2a and 3 (scenarios 1 and 2) in Tables 7-2, 7-3, 7-4 and 7-5. Option 2a only was estimated since the cost of Option 2b would be greater to accommodate 1150 m of pressure pipe to connect to the Marchmont pump station. Tables 7-4 and 7-5 compare the Option 3 for upgrade to the Marchmont flood pump station for a scenario of maximum storage in the slough and minimum storage in the slough. A conceptual sketch for an intake structure on the slough is provided in Appendix 3.

TABLE 7-3 OPTION 2 - MCKINSTRY ROAD PUMP STATION AXIAL FLOW PROPELLER DRAINAGE PUMPS Item Description Cost Estimate 1 Mobilization and Demobilization $40,000 2 Civil Construction of Pump Station - Excavation and Cofferdam; dewatering $70,000 - Concrete Construction (80 m3 @ $2,000/m3) $160,000 - Metalwork, bar screen and Drainage Connections $30,000 - Building & Architectural $60,000 - Landscaping & Site Finish $30,000 3 Forcemain - 250 m – 600 diam HDPE @ $400/m $100,000 - Discharge headworks $20,000 4 Pump Supply $80,000 5 Control Kiosk and Electrical Supply $120,000 6 Mechanical Installations $100,000 7 Electrical Installations $120,000 9 Commissioning $20,000 Sub-total $950,000 Engineering and Contingency at 30% $285,000 Total Cost Estimate – Option 1 $1,235,000

Financing

1. 2/3 Grant $1,000,000 $667,000 2. City of Duncan cost $568,000 3. 35 year, 4% debenture – annual cost $30,433/year - Cost per household – 5035 / 2.2 = 2289 DU $13.30/year - DU

TABLE 7-4 OPTION 1 - LEE STREET PUMP STATION SCREW IMPELLER DRAINAGE PUMP Item Description Cost Estimate 1 Mobilization and Demobilization $40,000 2 Civil Construction of Pump Station - Excavation and Cofferdam; dewatering $90,000 - Concrete Construction (160 m3 @ $2,000/m3) $320,000 - Metalwork, Bar screen, safety $40,000 - Building & Architectural $70,000 - Landscaping & Site Finish $30,000 3 Forcemain - 60 m – 600 diam HDPE @ $500/m $30,000 - Discharge headworks $20,000 4 Pump Supply $160,000 5 Control Kiosk and Electrical Supply $120,000 6 Mechanical Installations $150,000 7 Electrical Installations $120,000 9 Commissioning $20,000 Subtotal $1,210,000 Engineering and Contingency at 30% $363,000 Total Cost Estimate – Option 2 $1,573,000

Financing

1. 2/3 Grant $1,000,000 $667,000 2. City of Duncan cost $906,000 3. 35 year, 4% debenture – annual cost $48,543/year - Cost per household – 5035 / 2.2 = 2289 DU $21.20/year - DU

TABLE 7-5 OPTION 3 – SCENARIO 1 - MARCHMONT PUMP STATION UPGRADE NEW AXIAL FLOW DRAINAGE PUMP (0.6 m3/s) Item Description Cost Estimate 1 Mobilization and Demobilization $40,000 2 Civil Construction of Intake Structure - Excavation and Cofferdam; dewatering $60,000 - Concrete Construction (70 m3 @ $2,000/m3) $140,000 - Metalwork, Bar screen, fish screen; safety access $70,000 - Building & Architectural $10,000 - Landscaping & Site Finish $20,000 - Provisions for storage will need to be made if used for 100 Not Estimated year protection; beaver dam removal is required. 3 Extend Drainage Pipe to intake - 150 m – 1,000 diam Conc @ $600/m (will need a larger $90,000 pipe to Marchmont flood pump station for flow reversal and Not estimated storage.) 4 Upgrade Marchmond Pump Station and forcemain: - New 600 V Electrical Supply; Power supply MCC and Transformer; Upgrade existing pumps $300,000 - Upgrade Building and Intake Forebay $180,000 - Replace Discharge Forcemain $90,000 5 New drainage Pump Supply (1 new 0.60 m3/s pump) $80,000 6 Mechanical Installations $90,000 7 Electrical Installations (Incl above) $0 9 Commissioning $20,000 Subtotal $1,190,000 Engineering and Contingency at 30% $357,000 Total Cost Estimate – Option 3 $1,547,000

Financing

1. 2/3 Grant $1,000,000 $667,000 2. City of Duncan cost $880,000 3. 35 year, 4% debenture – annual cost $47,150/year - Cost per household – 5035 / 2.2 = 2289 DU $20.60/year - DU

TABLE 7-6 OPTION 3 – SCENARIO 2 - MARCHMONT PUMP STATION UPGRADE TWO NEW AXIAL FLOW DRAINAGE PUMPS (2.0 M3/S) Item Description Cost Estimate 1 Mobilization and Demobilization $40,000 2 Civil Construction of Intake Structure - Excavation and Cofferdam; dewatering $60,000 - Concrete Construction (70 m3 @ $2,000/m3) $140,000 - Metalwork, Bar screen, fish screen; safety access $70,000 - Building & Architectural $10,000 - Landscaping & Site Finish $20,000 3 Extend Drainage Pipe to intake - 150 m – 750 diam Conc @ $400/m $60,000 4 Upgrade Marchmond Pump Station and forcemain: - New 600 V Electrical Supply; Power supply MCC and Transformer; Upgrade existing pumps $400,000 - Upgrade Building and Intake Forebay $180,000 - Replace Discharge Forcemain $90,000 5 New drainage Pump Supply (2 new 1.0 m3/s pumps) $180,000 6 Mechanical Installations $120,000 7 Electrical Installations (Incl above) $0 9 Commissioning $20,000 Subtotal $1,390,000 Engineering and Contingency at 30% $417,000 Total Cost Estimate – Option 3 $1,807,000

Financing

1. 2/3 Grant $1,000,000 $667,000 2. City of Duncan cost $1,140,000 3. 35 year, 4% debenture – annual cost $61,081/year - Cost per household – 5035 / 2.2 = 2289 DU $26.70/year - DU

The cost estimate summary is provided in Table 7-7, as follows:

Cost Estimate Annual Upgrade Description (incl. 30% Financing per Option contin.) DU after grant Option 1 Lee Street Pump Station $1,573,000 $21.20 Option 2a * McKinstry Road Pump Station $1,235,000 $13.30 Option 3, Marchmont Pump Station Upgrade $1,547,000 $20.60 Scenario 1 Option 3, Marchmont Pump Station Upgrade – $1,807,000 $26.70 Scenario 2

* Note: Option 2b requires 1150 m of forcemain to Marchmont pump station. This added cost and other impact are concluded to make this alternative unacceptable for cost.

Based on the Capital cost estimates, we are able to show that the upgrade of the Marchmont Pump Station under Scenario 1 is less than the cost to construct Option 1 a new screw pump station in the Fish Gut Alley Slough. However since Options 1 and 2a do not offer the 100 year protection to the flood plain, and Option 3 (Scenario 1) can only offer the 100 year protection to the flood plain at high environmental cost in the slough, none are acceptable. If the pump station can be upgraded under Option 3 (Scenario 2) to provide adequate drainage for the entire catchment, the estimated additional cost is approximately $260,000 for the complete upgrade. If fully implemented, this upgrade would provide the City with full flood protection for the entire catchment of 92 ha for the 100 year return storm.

8.0 RECOMMENDATIONS

The recommendations are that the City upgrade the Marchmont Pump Station under Option 3, Scenario 2 to provide protection from flooding for the entire catchment of 92 ha under a 100 year return flood. If the City does not have adequate funding for this upgrade, the preferred option is to upgrade the pump station under Option 3, Scenario 1, and to provide capacity for the upgrade to Scenario 2 in future as additional funds become available.

SUMMARY OF FINDINGS

TRUNK ROAD/CANANDA AVENUE & TRUNK ROAD/COWICHAN WAY

City of Duncan

DATE: May 25, 2011

File: 1211

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SUMMARY OF FINDINGS TRUNK ROAD/CANANDA AVENUE & TRUNK ROAD/COWICHAN WAY CITY OF DUNCAN

TABLE OF CONTENTS 1.0 Introduction ...... 1 1.1 Background...... 1 2.0 Problem Statement...... 1 3.0 Existing Conditions ...... 1 3.1 Railway...... 1 3.2 Loop Detectors ...... 2 3.4 Signal Timing ...... 2 4.0 Phasing Options...... 3 4.1 Option 1 – Existing Phasing ...... 3 4.2 Option 2 – Revised Phasing Sequence ...... 4 4.3 Option 3 – Dallas Left Turn Phasing with Existing Phase Sequence ...... 5 4.4 Option 4 – Dallas Left Turn Phasing with Proposed Phase Sequence...... 6 5.0 Traffic Volumes...... 7 6.0 Analysis ...... 10 7.0 Summary...... 11 8.0 Hardwire Connection...... 11 9.0 Time of Day...... 12 10.0 Pedestrian Signals...... 13 11.0 Pavement Markings and Signage...... 13 12.0 Power Connection...... 13 13.0 Summary of Costs ...... 14 14.0 Recommendations ...... 14

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SUMMARY OF FINDINGS TRUNK ROAD/CANANDA AVENUE & TRUNK ROAD/COWICHAN WAY CITY OF DUNCAN

1.0 INTRODUCTION Boulevard Transportation Group was retained by the City of Duncan to undertake a review of the existing operations of the two traffic signals at Trunk Road/Canada Avenue and Trunk Road/Cowichan Way/Duncan Street and explore alternative configurations and identify areas for potential improvement or change.

1.1 Background In 2002, the City of Duncan and Cowichan Tribes undertook a joint Traffic Study for the Duncan area. One of the recommendations of the report was to work towards creating a one way couple using Canada Avenue and Duncan Street. Part of this recommendation was to signal the intersection of Duncan Street/Cowichan Way/Trunk Road. Additional goals the signalization included improved access to Downtown, improved access to Duncan Street (and parking), and to reduce pressure on the Trunk Road/Highway 1 signal. The City movement forward with the signalization of Cowichan Way/Trunk Road in 2010.

2.0 PROBLEM STATEMENT Following the installation of the signal at Cowichan Way/Trunk Street the City has received numerous complaints regarding the operations including significant delays on Trunk Road and Canada Avenue, the signal not responding to vehicle calls, and confusion over the signal phasing.

This project was to identify and quantify the existing issues and identify potential migration measures to reduce the impacts of the two signals.

3.0 EXISTING CONDITIONS 3.1 Railway The railway line runs north-south approximately halfway between Cowichan Way and Canada Avenue. The train station is located approximately 115m north of Trunk Road. Currently the railway pre-emption time is set at 22 seconds which consists of 5 seconds of right of way transfer time, 13 seconds of queue clearance (eastbound at Cowichan Way and westbound at Canada Avenue), and 4 seconds of yellow separation time. This amount of pre-emption time is not sufficient to accommodate pedestrians crossing the street should the northbound/southbound phases be in operation when pre- emption is triggered. Ie. pedestrians who have just stepped off the sidewalk at Canada Avenue/Trunk Road when pre-emption starts will have 5 seconds to finish crossing Trunk Road before the westbound PAGE 1

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SUMMARY OF FINDINGS TRUNK ROAD/CANANDA AVENUE & TRUNK ROAD/COWICHAN WAY CITY OF DUNCAN movement on Trunk Road starts to clear the queue from the railway tracks. The pedestrian crossing time is calculated as 11 seconds, which is 6 seconds longer than would be provided by the railway pre- emption.

Initial discussions have been held with Southern Railway and the cost to move the sensors would be in the $15,000-$20,000 range. The City should hold discussions with Southern Railway (Operations Manager) regarding the cost and need to relocate the sensors.

3.2 Loop Detectors Loops are installed on all approaches at Cowichan Way/Trunk Road (excluding Duncan Street); however, these loops are currently turned off to allow the signal to operate in pretimed coordination, but are operational.

At Canada Avenue/Trunk Road existing loop detectors are located in the westbound through lane, southbound lanes, and eastbound left and through lanes. The westbound right turn lane does not have a loop detector. The eastbound detectors should be investigated further to determine if they need to be replaced as initial investigations found that it was tied into the westbound through detector for unknown reasons. The westbound through detectors were found to be operational prior to being turned off as part of the installation of the adjacent signal. The detectors will be required to maximize the efficient of the signal timing when in an actuated mode.

3.4 Signal Timing The two traffic signals are currently running in pretimed coordination 24 hours a day / 7 days a week with an 81 second cycle length. There is no hardwired or radio/cellular communication between the two controllers to allow one controller to know that the other is switching a phase or time of day plan. The signals remain synchronized, in terms of time, through the use of GPS time clocks.

Identified Issues: The phasing recorded on the signal timing sheets indicates the eastbound movements as phase 2 and the westbound movements as phase 6; however in the controller westbound is phase 2 and eastbound is phase 6. The signal timings by movement match; however there may be future confusion if the signal timing sheets and controller outputs are not updated to reflect the same phasing numbering and direction.

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SUMMARY OF FINDINGS TRUNK ROAD/CANANDA AVENUE & TRUNK ROAD/COWICHAN WAY CITY OF DUNCAN

A comparison of the phasing on the signal timing sheets and the electrical drawings shows two different phasing sequences and numbering. Similar to the controller outputs the electrical drawings show the westbound movement as phase 2 which conflicts with the signal timing sheets.

All-red phases used to prevent ‘yellow trap’ shuts down the eastbound movement at Cowichan Way/Trunk Road for one second.

Other issues identified include:  Signal doesn’t “detect” or respond to vehicles, particularly in the evening  Long delays on Canada Avenue  Signage and pavement markings issues  Pedestrians jay-walking, and  Pedestrian signal at Trunk Road/Cowichan Way not called during certain eastbound phases.

4.0 PHASING OPTIONS The following options have been identified and reviewed:  Maintain existing phasing sequence  Change the phase sequence to southbound to eastbound, eastbound/westbound, northbound to westbound.  Utilize Dallas left turn phasing for the westbound left turns at Cowichan Way with existing phase sequence  Utilize Dallas left turn phasing for the eastbound left turns at Canada Avenue with revised phase sequence

Discussion on each of these options and what they mean is outlined in the following sections.

4.1 Option 1 – Existing Phasing This option maintains existing phasing and infrastructure. The existing signal phasing utilizes a 1 second all red at Cowichan Way/Trunk Road.

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SUMMARY OF FINDINGS TRUNK ROAD/CANANDA AVENUE & TRUNK ROAD/COWICHAN WAY CITY OF DUNCAN

1. Canada South & Cowichan East 2. Canada West & Cowichan North

3.Canada East/West & Cowichan East/West 4. All Red (Stop) for 1 second

Figure 1 – Existing Phasing Sequence

In this option the traffic controller should be re-programmed to ensure that the timing sheets and controller match. This would be at a cost of $4,000 unless the work could be done under warranty by the traffic controller supplier as they inputted the information ‘backwards’ to the timing sheets.

4.2 Option 2 – Revised Phasing Sequence This option would change the phasing of the two controllers to have Canada Avenue (southbound) and eastbound at Cowichan Way start the sequence. Then eastbound/westbound at both signals followed by northbound (Cowichan Way) and westbound at Canada Avenue. (Based on figure 1 the phasing in this option would be #1, #3, #4, #2). This phasing has a similar ‘left turn trap’ issue as Option 1 except in this option the westbound movement at Canada Avenue will be shut down for 1 second to eliminate the left turn trap. See Figure 2 for details on the left turn trap.

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SUMMARY OF FINDINGS TRUNK ROAD/CANANDA AVENUE & TRUNK ROAD/COWICHAN WAY CITY OF DUNCAN

Figure 2 – Left Turn Trap Created at Trunk Road/Cowichan Way under Existing Phasing

This option does not require any additional hardware, but would require re-programming the signal timings within the controller at a cost of $4,000.

4.3 Option 3 – Dallas Left Turn Phasing with Existing Phase Sequence Options 1 and 2 create a left turn trap situation which is mitigated by creating a 1 second all red at the intersection with the left turn trap. This one second all red shuts down an eastbound/westbound movement for one second and then re-starts the movement. Since this is an unfamiliar situation drivers are confused by the need for a one second all red.

This option eliminates the need for the one second all red at the intersection of Cowichan Way/Trunk Road. A separate signal head for the westbound left turn movement would be provided. This signal head would display the same colour (phase) as the eastbound movement, but not necessarily the same as the westbound through movement.

Figure 3 – Dallas Phasing Sequence (option 4 illustrated)

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SUMMARY OF FINDINGS TRUNK ROAD/CANANDA AVENUE & TRUNK ROAD/COWICHAN WAY CITY OF DUNCAN

This phasing would allow the eastbound movement to continue green without the one second all red. Signage, louvers, and public education are critical to this option.

Previous research has shown that Dallas phasing reduces delay and improves safety (NCHRP Report 493); however this type of phasing is unfamiliar to Duncan (BC) motorists.

The cost to implement this option depends on whether the extra signal head is mounted overhead on the signal arm or a new pole is placed in the centre median. The existing (new) signal pole for the westbound movement is an ‘L’ pole; however this pole lacks capacity to handle the additional overhead signal head and associated signage and would need to be upgraded to an ‘M’ pole at a cost of $40,000. The option to implement a pole and signal head within the centre median would be $20,000 and includes the cost to re-program the signal.

4.4 Option 4 – Dallas Left Turn Phasing with Proposed Phase Sequence This option is similar to Option 3 by allowing the removal of the one second all red from the intersection of Canada Avenue/Trunk Road with the addition of an eastbound left turn signal head. The eastbound left turn movement has approximately 90 vehicles per hour which is six times more vehicles using the ‘Dallas’ phasing signal compared to Option 3.

Canada East/West & Cowichan East/West Canada West & Cowichan North Figure 4 – Allowable Phasing Sequence with Dallas Phasing

The costs for this option are similar to Option 3 with $40,000 required to replace the existing eastbound pole to an ‘M’ pole. Alternatively a pole and signal head can be mounted in the centre median for a cost of $20,000.

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SUMMARY OF FINDINGS TRUNK ROAD/CANANDA AVENUE & TRUNK ROAD/COWICHAN WAY CITY OF DUNCAN

5.0 TRAFFIC VOLUMES Traffic counts were undertaken at the two intersections in late March/early April 2011. The traffic counts were undertaken on a weekday between 7-9am, 11:30am-1:30pm, and 3-7pm and on a Saturday between 11:30am-1:30pm and 3-7pm. The peak hours for the intersections occurred as follows: Weekday Am Peak Hour = 8-9am Weekday Mid-day Peak Hour = 12-1pm Weekday Pm Peak Hour = 4-5pm Saturday Mid-day Peak Hour = 12:15-1:15pm Saturday Pm Peak Hour = 3:15-4:15pm

The following illustrate the various peak hours.

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SUMMARY OF FINDINGS TRUNK ROAD/CANANDA AVENUE & TRUNK ROAD/COWICHAN WAY CITY OF DUNCAN

For the pm peak hour a comparison of 2008 to 2011 traffic volumes was undertaken to determine the changes in traffic pattern (if any) due to the addition of the Cowichan Way/Trunk Road traffic signal.

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SUMMARY OF FINDINGS TRUNK ROAD/CANANDA AVENUE & TRUNK ROAD/COWICHAN WAY CITY OF DUNCAN

The results found the following:  A decrease in southbound left turn vehicles on Canada Avenue (to Trunk Road) which have shifted to eastbound through on Government (ie. Are exiting downtown via alternate routes)  A decrease in westbound through (52 vph) and westbound right (14 vph) at Canada Avenue  A significant increase in northbound left turn volumes at Cowichan Way – 127 vph  20 vph travel northbound through from Cowichan Way to Duncan Street  A shift in eastbound traffic from through to right and general increase in eastbound right turns (94 vph) at Cowichan Way / Trunk Road (ie. more traffic using Cowichan Way)  A decrease in westbound through traffic which exceeds the shift to northbound left (127 vph) and westbound right (28 vph). The decrease in westbound through traffic is 79 vph after consideration of shifted traffic.

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SUMMARY OF FINDINGS TRUNK ROAD/CANANDA AVENUE & TRUNK ROAD/COWICHAN WAY CITY OF DUNCAN

6.0 ANALYSIS The four options were analyzed using Synchro. The following tables outline the results.

Table 1: Synchro LOS & Queue Results for Trunk Road/Canada Avenue LOS and Delay in seconds (Synchro) Queue in metres (Synchro) Movement Option 1 Option 2 Option Option Option Option Option Option 3 4 1 2 3 4 SBL E (66.6) D (44.9) C (30.3) C (33.9) 126.6m 119.8m 96.3m 100.2m SBR A (6.1) A 95.4) A (4.6) A (4.6) 11.7m 11.2m 10.9m 10.4m EBL C (25.9) D (53.7) C (34.5) B (15.4) 18.7m 27.5m 21.7m 14.4m EBT C (24.3) C (24.4) C (32.0) C (35.0) 53.0m 54.3m 61.6m 63.8m WBT A (4.7) A (6.7) B (11.9) A (9.5) 7.5m 13.9m 32.9m 20.6m WBR A (1.3) A (1.5) A (2.0) A (1.7) 0.0m 0.0m 0.6m 0.0m

Option 4 with the revised phasing sequence and the Dallas phasing provides the best LOS of the four options and improved southbound left queue lengths over existing.

Table 2: Synchro LOS & Queue Results for Trunk Rd/Cowichan Way LOS and Delay in seconds (Synchro) Queue in metres (Synchro) Movement Option 1 Option 2 Option Option Option Option Option Option 3 4 1 2 3 4 NBL/T D (38.6) C (30.9) C (31.8) C (30.9) 49.8m 47.2m 47.2m 47.2m NBR B (11.9) B (10.1) B (10.1) B (10.1) 2.6m 2.5m 2.5m 2.5m EBT/R A (3.3) A (1.9) A (3.5) A (2.7) 3.1m 0.5m 16.9m 0.5m WBL C (21.6) C (24.2) A (7.6) C (24.2) 5.9m 6.4m 3.3m 6.4m WBT/R C (23.6) C (26.6) C (26.7) C (26.7) 58.0m 63.2m 63.2m 63.2m

Options 2, 3 and 4 have improved northbound left/through operation compared to existing (option 1). The other movements show no significant change in operation between the four scenarios except for the westbound left turn movement in option 3 where the delay is improved due to the dallas left turn for that movement. There is no significant difference in the queue lengths between the four options.

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SUMMARY OF FINDINGS TRUNK ROAD/CANANDA AVENUE & TRUNK ROAD/COWICHAN WAY CITY OF DUNCAN

7.0 SUMMARY The following table summarizes the findings of the option review.

Table 3: Summary of Options Option Costs Delays (at Canada) Queues (at Canada) Safety Existing $4,000 Extensive SB delays Extensive SB queues No change Sequence Proposed $4,000 Improved SB delays; No significant change No change Sequence Increased EBL delays from existing Dallas + Existing $20,000 Significantly reduced SB Improved SB queues Improved Sequence delays; Increased EBT delays Dallas + Proposed $20,000 Significantly reduced SB Reduced SB queues Improved Sequence delays, reduced EBL delay; Increase in EBT delays

8.0 HARDWIRE CONNECTION The two controllers are currently operating without a hardwire connection. In place of a hardwire connection, GPS time clocks were installed in each cabinet at a total cost of $1,372.20 (excluding taxes). The GPS time clocks work by synchronizing with a GPS satellite rather than running separate internal clocks within each cabinet. Because the time clocks are obtaining the time from the same source they will remain synchronized at all times.

Hardwiring two traffic controllers together allows one signal to send ‘instructions’ or information to another signal (or multiple signals). The information that can be shared between the two controllers is the cycle length, offset, and splits. Ie. One controller tells another controller which time of day plan to run and when. The GPS does not allow direct communication between the controllers; however, as long as the clocks in the two controllers are the same they would perform the same as two controllers hardwired together.

Hardwiring of the two signals is possible through the use of an existing conduit under the railway. Further discussions are required with Southern Rail to secure the use of the conduit. Previous discussion with Southern indicate that a $750 documentation fee and an additional $750 application documentation fee is require to gain approval to install a conduit and then there would be an annual crossing fee of $850 per year to utilize the conduit. PAGE 11

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The cost to install the hardwire conduit is $5,000 not including any costs associated with use of the conduit. It may be possible to obtain a refund on the GPS time clocks to offset the cost of the hardwiring; however discussions with Raylec and the supplier would be necessary to determine if this is possible.

9.0 TIME OF DAY The signals are currently running in fixed time coordination 24 hours a day. By running in fixed time each movement is serviced (given green time) whether there is a vehicle present or not. During the daytime period this may be a minor issue as traffic would typically be present on all legs of the two intersections and only occasionally would a leg not have any volume during its portion of the cycle. However in the evening, once most of the downtown businesses have closed, traffic volumes drop and there is an increased likelihood that one or more legs will be provided service when no vehicle is present. This creates driver frustration and increases the changes of disobedience of the traffic control devices (signals).

Previous work on the intersection indicated that the signal was fixed timed due to concerns over the unpredictable freight train schedule and the potential for vehicles to be between the two signals (and over the tracks) on Trunk Road when a train is approaching. With lower traffic volumes in the evening and overnight period and the presence of the railway pre-emption any vehicles which become queued between the two signals should be cleared by the pre-emption prior to the train arriving. In addition, if the signal is actuated during the overnight period the signal can ‘rest’ (remain green) on Trunk Road which would reduce the likelihood of vehicles being stopped on Trunk Road as the light would only change to a side street if a vehicle was present and the adjacent signal would remain in green (unless a side street vehicle approached at the adjacent signal at the same time).

A review of traffic volume data over a 24 hour period on Government Street near Allenby Road found that there are two peaks in volume – one in the am (8am-9am) and one in the pm (4pm-5pm) with traffic remaining high between 7:00am and 7:00pm. Traffic volumes steadily decrease outside of this time period.

Therefore it is recommended that the traffic signal operate in fixed time coordination between 7:00am and 7:00pm and as two actuated signals between 7:00pm and 7:00am.

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SUMMARY OF FINDINGS TRUNK ROAD/CANANDA AVENUE & TRUNK ROAD/COWICHAN WAY CITY OF DUNCAN

10.0 PEDESTRIAN SIGNALS Field observations found that the pedestrian signal for crossing the south leg of the Trunk Road/Cowichan Way intersection did not always provide a walk signal when the eastbound movement had a green signal. The City should have the pedestrian calls within the controller reviewed to identify if this is a programming issue.

11.0 PAVEMENT MARKINGS AND SIGNAGE The existing pavement markings on Cowichan Way indicate a left turn lane and a right turn lane; however the existing laning is for a left/through and a right turn lane. A through arrow should be added to the left turn arrow to indicate that vehicles can now go straight through on Cowichan Way to Duncan Street. A sign (special version of R-086-R) should be posted on the shoulder to reinforce the pavement markings.

12.0 POWER CONNECTION Discussions have been held with BC Hydro and it has been confirmed that the two signals are receiving their power from two different circuits. With the two signals on different circuits there is the potential that one signal may be on while the other is in flash or off and lead to driver confusion. BC Hydro is in the process of preparing a cost estimate to put the two signals on the same circuit. A railway crossing permit may be required to complete the work of putting the two signals on the same circuit.

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SUMMARY OF FINDINGS TRUNK ROAD/CANANDA AVENUE & TRUNK ROAD/COWICHAN WAY CITY OF DUNCAN

13.0 SUMMARY OF COSTS The following table outlines the cost of various components of making changes at the intersections of Canada Avenue/Trunk Road and Cowichan Way/Trunk Road: Option Cost Existing Sequence – Signal Re-timing $4,000 Proposed Sequence – Signal Re-timing $4,000 Dallas + Existing Sequence – New hardware (median signal pole) & signal re- $20,000 timing Dallas + Proposed Sequence – New hardware (median signal pole) & signal $20,000 re-timing Relocate Railway Sensors for Pre-emption $20,000 Loops at Canada Avenue/Trunk Road $3,500 Installing Hardwire $6,500 + ongoing fee of $850/ year Signage & Paint $1,000

The above costs excludes any engineering costs (ie. signal timing sheet preparation, revised electrical drawings/design).

14.0 RECOMMENDATIONS The following changes are recommended as the best option:  Revised signal phasing sequence to Southbound-Eastbound; Eastbound/Westbound; Northbound- Westbound.  Implement Dallas Phasing at Canada Avenue with signal head located within the median for the eastbound left turn.  Maintain the GPS time clocks.  From 7:00pm to 7:00am remove coordination and run signals as actuated and resting in green on Trunk Road.  Undertake an education program on the new Phasing (including Dallas) using the newspapers, local daily television (Shaw cable), business groups, and the City’s website.  Updated pavement markings on Cowichan Way (re-paint with left/through arrows) and a sign indicating the lane use.  Work with BC Hydro to ensure that the two traffic signals are on the same circuit. PAGE 14

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The cost to construct the above recommendations is $21,000 without the Hydro change and education program or any engineering costs. Additional costs for engineering (electrical and traffic) will be required.

The City should also have the electrical drawings and the timings within the traffic signals updated to match the phase numbering on the signal timing sheets. At the same time the City should have the pedestrian programming for the eastbound movement at Cowichan Way/Trunk Road reviewed to identify why the pedestrian calls don’t always call the pedestrian phase.

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