Creek Inventory and Assessment Study Final Report planning/ErosionStudy-2015.pdf · Creek Inventory and Assessment Study Final Report A report submitted by: Aquafor Beech Ltd. June

Prepared for:

Engineering and Construction Town of Oakville

1225 Trafalgar Road Oakville, ON L6J 5A6

Creek Inventory and Assessment Study

Final Report

A report submitted by: Aquafor Beech Ltd.

June 9, 2016

Contact:

Anna Howes, M.Sc., P.Eng. Water Resources Engineer

Aquafor Beech Ltd. [email protected]

2600 Skymark Avenue Building 6, Unit 202

Mississauga, ON L4W 5B2 T. 905.629.0099 ext.239

Aquafor Beech Reference: 65759

Creek Inventory and Assessment Study June 9, 2016 Final Report

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TABLE OF CONTENTS 1 Introduction ............................................................................................................................. 1

1.1 Purpose ............................................................................................................................. 1 1.2 Report Outline .................................................................................................................. 1

2 Background/Overview of Conditions ..................................................................................... 1 2.1 Creek Works Undertaken or Underway since the 2010 Study......................................... 1 2.2 Major Storm Events ......................................................................................................... 2 2.3 Reach-Based Assessment ................................................................................................. 3 2.4 Overview of Creeks Assessed .......................................................................................... 6

2.4.1 Sheldon Creek ........................................................................................................... 9 2.4.2 Fourteen Mile Creek and its Tributaries ................................................................... 9 2.4.3 McCraney Creek ....................................................................................................... 9 2.4.4 Taplow Creek ............................................................................................................ 9 2.4.5 Glen Oak Creek....................................................................................................... 10 2.4.6 Shannon’s Creek ..................................................................................................... 10 2.4.7 Munn’s Creek.......................................................................................................... 10 2.4.8 Morrison Creek West Branch ................................................................................. 10 2.4.9 Morrison Creek East Branch ................................................................................... 11 2.4.10 Morrison Creek Main Branch ................................................................................. 11 2.4.11 Falgarwood Creek ................................................................................................... 11 2.4.12 Wedgewood Creek .................................................................................................. 11 2.4.13 Joshua’s Creek ........................................................................................................ 11 2.4.14 Clearview Creek...................................................................................................... 12

3 Creek Assessment Methodology........................................................................................... 12 3.1 Overview ........................................................................................................................ 12 3.2 Geomorphic Assessment ................................................................................................ 12

3.2.1 Assessment Tools.................................................................................................... 13 3.3 Erosion Risk Assessment ............................................................................................... 14

3.3.1 Inventory of Creek Erosion ..................................................................................... 14 3.3.2 Inventory of Outfalls, Pedestrian Crossings, and Debris Jams ............................... 17

3.4 Evaluation and Prioritization of Risk Locations ............................................................ 17 3.5 Rehabilitation Techniques .............................................................................................. 17

3.5.1 Armourstone Wall Protection ................................................................................. 18 3.5.2 Vegetated Geogrid/Coir Mat................................................................................... 18 3.5.3 Live Crib Wall ........................................................................................................ 19 3.5.4 Live Staking ............................................................................................................ 20 3.5.5 Rib Structures.......................................................................................................... 21 3.5.6 Deflectors ................................................................................................................ 22 3.5.7 Terraced Floodplain ................................................................................................ 23 3.5.8 Channel Realignment .............................................................................................. 24 3.5.9 Summary of Advantages and Disadvantages .......................................................... 24

3.6 Additional Opportunities ................................................................................................ 26 4 Creek Assessment Results and Recommendations ............................................................... 27

4.1 Geomorphology Evaluation Results .............................................................................. 27 4.2 Priority Areas of Concern .............................................................................................. 29


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4.3 Reach Long Areas of Concern ....................................................................................... 34 4.3.1 East Morrison Creek, Reaches 39-45 ...................................................................... 34 4.3.2 Munn’s Creek, Reaches 33-35 ................................................................................ 38 4.3.3 Joshua’s Creek, Reaches 67-68 ............................................................................... 41

4.4 Localized Areas of Concern ........................................................................................... 41 4.4.1 McCraney Creek Reach 21 ..................................................................................... 42 4.4.2 Glen Oak Creek, Reach 32a .................................................................................... 42 4.4.3 Fourteen Mile Creek, Reach 5 ................................................................................ 43 4.4.4 Glen Oak Creek, Reach 30...................................................................................... 44 4.4.5 McCraney Creek, Reach 22 .................................................................................... 44 4.4.6 Fourteen Mile Creek, Reach 5a .............................................................................. 45 4.4.7 McCraney Creek, Reach 17 .................................................................................... 45

4.5 Areas of Concern associated with Road Crossings ........................................................ 46 4.5.1 Falgarwood Creek, Reach 54a ................................................................................ 46 4.5.2 Wedgewood Creek, Reach 95 ................................................................................. 46 4.5.3 Wedgewood Creek, Reach 58 ................................................................................. 47

4.6 Areas of Concern Recommended for Monitoring .......................................................... 47 4.7 Estimated Costs and Implementation Schedule for Creek Rehabilitation ..................... 48 4.8 Outfalls, Pedestrian Crossings, and Debris Jams ........................................................... 52

4.8.1 Storm Sewer Outfalls .............................................................................................. 52 4.8.2 Pedestrian Crossings ............................................................................................... 53 4.8.3 Debris Jams ............................................................................................................. 54

5 Recommendations ................................................................................................................. 58 6 References ............................................................................................................................. 60 Appendix A: Geomorphic Summary of Reaches Appendix B: Sample Data Collection Forms Appendix C: Details for Reach Long Areas of Concern Appendix D: Details for Localized Areas of Concern Appendix E: Details for Areas of Concern associated with Road Crossings Appendix F: Details for Areas of Concern Recommended for Monitoring Appendix G: Summary Sheets for Priority Storm Sewer Outfalls Appendix H: Summary Sheets for Priority Pedestrian Crossings LIST OF FIGURES Figure 2.1: Total Rainfall Distribution for August 4, 2014 Storm ................................................. 3 Figure 2.2: Oakville Creeks West ................................................................................................... 7 Figure 2.3: Oakville Creeks East .................................................................................................... 8 Figure 3.1: Typical Detail of Armourstone Wall .......................................................................... 18 Figure 3.2: Typical Detail of Vegetated Geogrid ......................................................................... 19 Figure 3.3: Typical Detail of Live Crib Wall ............................................................................... 20 Figure 3.4: Typical Detail of Live Staking ................................................................................... 21 Figure 3.5: Typical Profile Detail of Rib Structure ...................................................................... 22 Figure 3.6: Typical Detail of Deflectors ....................................................................................... 23 Figure 3.7: Typical Terraced Floodplain Detail ........................................................................... 24


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Figure 3.8: Example of Channel Realignment for Infrastructure Protection ................................ 24 Figure 4.1: Locations of Priority Areas of Concern ..................................................................... 33 Figure 4.2: Failing bank protection and outfall in deteriorated condition in Reach 39 of Morrison Creek ............................................................................................................................................. 35 Figure 4.3: Downstream locations for monitoring and possible emergency works on East Morrison Creek ............................................................................................................................. 36 Figure 4.4: Upstream locations for monitoring and possible emergency works on East Morrison Creek ............................................................................................................................................. 37 Figure 4.5: Failing gabion basket revetments, perched culvert, and bank erosion adjacent to a parking lot on Munn’s Creek ........................................................................................................ 39 Figure 4.6: Locations for monitoring and possible emergency works on Munn’s Creek............. 40 Figure 4.7: Failing gabion basket revetments along Joshua’s Creek including erosion at bridge piers, outflanking of the gabions, and exposure of a concrete sanitary sewer encasement .......... 41 Figure 4.8: West abutment at Lakeshore Road, exposed metal conduit at storm outfall channel, and perched condition of Rebecca Street crossing ....................................................................... 42 Figure 4.9: Knick point with concrete cap under Speers Road, gabions in disrepair at Pinegrove Road, and drop in channel bed under Pinegrove Road ................................................................. 43 Figure 4.10: Localized gabion basket failure and concrete ford ................................................... 44 Figure 4.11: Leaning trees and failing gabion basket revetments on Glen Oak Creek ................ 44 Figure 4.12: Failing gabion baskets at Fourth Line culvert .......................................................... 45 Figure 4.13: Bank erosion on the west bank ................................................................................. 45 Figure 4.14: Perched culvert for Pilgrims Way and bank erosion adjacent to recreational trail .. 46 Figure 4.15: Perched culvert and disconnected CSP downstream of Falgarwood Drive ............. 46 Figure 4.16: Amber Crescent culvert with rusted base and Duncan Road culvert with failing gabion basket revetments .............................................................................................................. 47 Figure 4.17: Upstream face of Drummond Road culvert with rip rap reducing capacity ............ 47 Figure 4.18: Armourstone wall at storm sewer ............................................................................. 53 Figure 4.19: Priority Storm Sewer Outfalls .................................................................................. 55 Figure 4.20: Priority Pedestrian Crossings ................................................................................... 56 Figure 4.21: Priority Debris Jams ................................................................................................. 57 Figure 5.1: Locations of reaches to be included in 2020 assessment ........................................... 59 LIST OF TABLES Table 2.1: Summary of Changes to Reach Delineation .................................................................. 4 Table 2.2: Summary of Creeks and Reaches Assessed ................................................................... 6 Table 3.1: Rapid Geomorphic Assessment Descriptions based on Index Value .......................... 13 Table 3.2: RSAT Stream Quality based on Score ......................................................................... 14 Table 3.3: Scoring for Distance to Risk Criterion ........................................................................ 15 Table 3.4: Scoring for Stress Criterion ......................................................................................... 15 Table 3.5: Scoring for Erodibility Criterion ................................................................................. 15 Table 3.6: Scoring for Resource Type Criterion ........................................................................... 16 Table 3.7: Scoring for Extent of Damage Criterion ...................................................................... 16 Table 3.8: Scoring for People at Risk Criterion ............................................................................ 16 Table 3.9: Advantages and Disadvantages of Rehabilitation Techniques .................................... 25 Table 4.1: Reaches with Highest RGA Stability Index Score ...................................................... 28


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Table 4.2: Summary of Reach Dominant Processes ..................................................................... 29 Table 4.3: Priority Reach Long Areas of Concern ....................................................................... 29 Table 4.4: Priority Localized Areas of Concern ........................................................................... 30 Table 4.5: Areas of Concern associated with Road Crossings ..................................................... 30 Table 4.6: Areas of Concern Recommended for Monitoring ....................................................... 31 Table 4.7: Unit Construction Costs used for Cost Estimates ........................................................ 48 Table 4.8: Restoration Cost Estimates for Reach Long Areas of Concern ................................... 49 Table 4.9: Restoration Cost Estimates for Localized Areas of Concern ...................................... 50 Table 4.10: Recommended Implementation Schedule for Restoration Projects, 2016-2020 ....... 52


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1 INTRODUCTION

1.1 Purpose There are approximately 12 watercourses that flow within the Town of Oakville in addition to the major watercourses, Sixteen Mile Creek and Bronte Creek. The watercourses generally drain from north to south, outletting to Lake Ontario. The majority of the Town’s watercourses have been affected by urbanization, altering hydrologic regimes, straightening and confining channel to limited corridors, and intermittently conveying watercourses within closed conduits (storm sewers). These changes to the watercourses can result in erosion which may put infrastructure and property at risk. This study is an update to the 2010 Creek Erosion Inventory and Assessment Study completed by AECOM and builds off the previous studies completed in 2008, 2006, and 2001. During the current study, field walks were conducted to assess watercourse conditions and identify risks to infrastructure and property. The purpose of the study is to develop an implementation plan to prioritize works on Town-owned watercourses and to provide cost estimates for budgetary planning purposes.

1.2 Report Outline The report has been divided into 3 subsequent sections as follows:

• Background/Overview of Conditions – This section describes the restoration works that have been undertaken since the 2010 study. It also includes a summary of the assessment process and the existing condition of the study watercourses.

• Creek Assessment Methodology – This section describes the approach used in the study to evaluate the existing watercourse and infrastructure conditions. As well, various erosion rehabilitation techniques are summarized.

• Creek Assessment Results and Recommendations – This section summarizes the prioritized works on Town watercourses along with estimated costs and an implementation plan.

2 BACKGROUND/OVERVIEW OF CONDITIONS The following subsections provide an update on creek works completed since the 2010 study as well as a summary of existing condition of the creeks assessed. Details of the Town’s geology, land use changes, and channel evolution can be found in the 2010 study.

2.1 Creek Works Undertaken or Underway since the 2010 Study Since the completion of the last Creek Erosion and Inventory Assessment Study (AECOM, 2011), the Town has completed the following erosion restoration works:

• Fourteen Mile Creek, Reach 2 – reach-based channel restoration (completed fall 2013).

• West Morrison Creek, Reaches 36-38 – Environmental assessment and detailed design (underway). These reaches were identified as the first priority for long areas of concern in the 2010 study. Construction is planned for 2017.



• Sheldon Creek, Reach 69 – localized repair to address damage upstream of the pedestrian bridge following August 2014 storm (completed winter 2015). This site was ranked seventh for localized areas of concern in the 2010 study.

• McCraney Creek, Reach 32 (Glen Oak Park) – localized replacement of bank protection (completed summer 2015). This site was ranked first for local areas of concern in the 2010 study.

• Glen Oak Creek, Reach 97 – localized realignment at Old Bridle Path (completed spring 2010).

• Taplow Creek, Reaches 24 and 25 – environmental assessment and detailed design for bank protection/stabilization (underway). Reach 24 was ranked second for areas of local concern in the 2010 study. Construction is planned for 2016 or early 2017.

• Wedgewood Creek, Reach 60 – detailed design is underway for the replacement of the Grand Boulevard culvert. Construction is planned for 2016.

• Munn’s Creek, Reach 34 – local repairs were completed on the upstream and downstream ends of the Miller Road culvert. Minor repairs were completed on the McCraney Street culvert. Works were completed in 2015.

2.2 Major Storm Events Since the last creek inventory in 2010, the Town of Oakville experienced only one major rainfall event. This event was the August 4, 2014 storm event which was centered over the City of Burlington. The storm is summarized in the Conservation Halton and Environmental Water Resources Group Ltd. report August 4th, 2014 Storm Event, Burlington (2015). Total rainfall for the event is presented in Figure 2.1 below from the CH and EWRG report. Within the Town of Oakville, the Sheldon Creek watershed was most impacted by the August 4, 2014 storm. Town staff walked the creek following the storm event and noted that there was evidence the creek had overtopped its banks and had spread extensively across the floodplain. The observed extents of flooding were approximately consistent with the extent of the floodplain limits for the 100-year storm event. The only channel emergency restoration works identified during the field walks were localized repairs in Reach 69 (noted above in Section 2.1) which were carried out in combination with the emergency repairs to the shoreline. However, the high flows from the August 4, 2014 event likely contributed to increased erosion within Sheldon Creek.



Figure 2.1: Total Rainfall Distribution for August 4, 2014 Storm Source: Conservation Halton and Environmental Water Resources Group Ltd. (2015)

2.3 Reach-Based Assessment Watercourse reaches are lengths of channel that display similar channel characteristics, functions, and processes and can be used as a guide for management objectives and restoration opportunities. Stream reaches are delineated by key factors that include hydrology, channel gradient, geology, valley setting, sinuosity, and riparian vegetation. The current assessment study was completed on a reach-basis, with erosion sites and geomorphic conditions summarized by reach. Reaches within the Town were previously delineated by others as described in the 2010 report (Section 2.5). These delineations were generally used during this update to the study; however, there were some instances where the reach break was modified slightly to account for observed field conditions. As well, an occasional additional reach break was added as deemed necessary. Changes to the reach delineation are summarized in Table 2.1. It should be noted, however, that although adjustments were made, some identified reaches could be further broken down to better represent the observed field conditions.



Table 2.1: Summary of Changes to Reach Delineation Reach Name Old Limits (AECOM, 2011) New Limits Fourteen Mile Creek

75b Upper Middle Road to corner of Bronte and Dundas Streets

Upper Middle Road to outfall from Spring Meadow Way SWM Pond

McCraney Creek 17 Indian Ridge Trail to second creek

crossing in Pilgrim’s Park Indian Ridge Trail pedestrian bridge to split flow upstream of first Pilgrims Way crossing

18 Second pedestrian bridge in Pilgrim’s Park to Pilgrims Way crossing

Split flow upstream of first Pilgrims Way crossing to Pilgrims Way

23 Engineered drainage below ground along Speers Road

Bridge Road to Pinegrove Road

Taplow Creek 26 Pilgrims Way to adjacent to Parson’s

Lane Pilgrims Way to pedestrian bridge downstream of Bonnybank Court outfall

27 Adjacent to Parson’s Lane to the northern arm of Pilgrims Way Road

Pedestrian bridge downstream of Bonnybank Court outfall to northern arm of Pilgrims Way

Glen Oak Creek 31 Adjacent to Unsworth Avenue to

adjacent to Trillium Drive Adjacent to Unsworth Avenue to end of private property where gabions end on east bank

32 Adjacent to Trillium Drive to Pinegrove Road

End of private property where gabions end on east bank to Pinegrove Road

Munn’s Creek 78 River Oaks Boulevard to Munn’s

Park River Oaks Boulevard to Munn’s Avenue

79 Munn’s Park to adjacent to Ross Lane Munn’s Avenue to outfall and culverts east of Margot Street

80 No active channel. No flow. No geomorphic assessment possible

Outfall and culverts east of Margot Street to River Glen Boulevard

81 No active channel. No flow. No geomorphic assessment possible

River Glen Boulevard to Dundas Street

Morrison Creek (Main) 46 Mouth of Morrison Creek at Lake

Ontario to adjacent to the art gallery immediately downstream of Lakeshore Road crossing

Lake Ontario to Lakeshore Road

47 Adjacent to the art gallery immediately downstream of Lakeshore Road crossing to wooden footbridge upstream of Lakeshore Road

Lakeshore Road to wooden foot bridge



Reach Name Old Limits (AECOM, 2011) New Limits 50 Adjacent to Botany Hill to adjacent to

Cedar Grove Boulevard Colbourne Park adjacent to Botany Hill Road to storm outfall from Balmoral Place

51 Adjacent to Cedar Grove Boulevard to the confluence of reaches 52 and 53

Storm outfall from Balmoral Place to confluence of Reaches 52 and 53

Morrison Creek East 43 Upper Middle Road to pedestrian

bridge near Grenville Park Upper Middle Road to storm outfall from Laurelwood Drive

44 Pedestrian bridge in Grenville Park to Glenashton Drive

Storm outfall from Laurelwood Drive to start of scrubby riparian area adjacent to Glenashton Drive

45 Glenashton Drive to Postridge Drive Start of scrubby riparian area adjacent to Glenashton Drive to Postridge Drive

Wedgewood Creek 59 Diversion channel to large eroding

pedestrian bridge adjacent to Edgeware Park

Morrison-Wedgewood Diversion Channel to the end of the roundstone bank protection just downstream of Grand Boulevard

60 Pedestrian bridge in Edgeware Park to adjacent to Griffith Place

End of roundstone bank protection just downstream of Grand Boulevard to pedestrian bridge adjacent to Griffith Place

Falgarwood Creek 54a This was part of Reach 54 in 2010 Morrison-Wedgewood Diversion

Channel to Falgarwood Drive 54 Diversion channel upstream of

industrial area to Gainsborough Drive Falgarwood Drive to Gainsborough Drive

Joshua’s Creek 63 Downstream of Lakeshore Road to

northern limits of the Southeast Sports Field

Combined Reaches 63 & 64 Lakeshore Road West to culvert and outfalls from Devon Road and Deer Run Avenue

64 Northern end of Southeast Sports Park to 3rd major meander bend upstream

65 Upstream of 3rd major meander bend north of Lakeshore Road to concrete box bridge

Combined Reaches 65 & 66 Culvert and outfalls from Devon Road and Deer Run Avenue to start of gabion baskets

66 Twin box culvert crossing to adjacent to Cedarberry Court

67 Adjacent to Cedarberry Court to concrete weir stretching across channel near Brook Place

Start of gabion baskets to concrete weir adjacent to Brook Place



Reach Name Old Limits (AECOM, 2011) New Limits Clearview Creek

90 Winston Churchill to adjacent to Aspen Forest Park

Winston Churchill Boulevard to railway

91 Adjacent to Aspen Forest Park to Beryl Road

Railway to Beryl Road

2.4 Overview of Creeks Assessed The creeks assessed in this study included those assessed in the 2010 study, except where subsequent development has converted watercourses to storm sewer infrastructure. The creeks assessed are presented in Figure 2.2 and Figure 2.3 while a summary of the reaches assessed and the dates of assessment is provided in Table 2.2. Table 2.2: Summary of Creeks and Reaches Assessed

Watercourse Reach Date Assessed

Sheldon Creek 69, 70, 71 06-Apr-15

Fourteen Mile Creek

1a 21-May-15 1, 2, 3, 4, 5, 5a, 5b, 9, 6a, 6, 7 07-Apr-15

9, 10, 11, 12, 13, 14, 14a, 14b, 15 14-Apr-15 72, 73, 74, 75, 76, 76aa, 75a 15-Apr-15

75b, 75c 06-Apr-15 76ab, 76a, 76b, 76e 17-Apr-15

McCraney Creek 21, 22 23-Apr-15 17, 18, 19, 19a, 19b 21-Apr-15

Taplow Creek 24, 25, 26, 27, 28 29-Apr-15

Glen Oak Creek

30, 32, 32a 23-Apr-15 29a 15-Apr-15

29a, 29, 29b 29-Apr-15 96, 97 23-Apr-15

Shannon’s Creek 92, 93, 94 06-May-15 Munn’s Creek 33, 34, 35, 77, 78, 79, 80, 81 12-May-15

Lower Morrison Creek 46, 47, 49, 50, 51 13-May-15 52, 52a 12-May-15

West Morrison Creek 82, 83, 84, 85, 86 06-May-15 East Morrison Creek 39, 40, 41, 42, 43, 44, 45 04-May-15 Falgarwood Creek 54 06-May-15

Wedgewood Creek 55a, 55, 56, 57, 58, 95 20-May-15 59, 60, 61 13-May-15

Joshua’s Creek 62, 63, 64, 65, 66, 67, 68 26-May-15

87, 88, 89, 89a, 89aa 20-May-15 88a, 88b, 89b 21-May-15

Clearview Creek 90, 91 26-May-15



Figure 2.2: Oakville Creeks West



Figure 2.3: Oakville Creeks East



2.4.1 Sheldon Creek Sheldon Creek was walked from Lake Ontario to Burloak Drive (Reaches 69-71). The creek is contained within a valley setting behind residential development in Reaches 69 and 71 and within Shell Park in Reach 70. Channel hardening measures such as concrete have been used in Reach 69 while bioengineering measures where noted in Reach 71. Where channel hardening has not been employed, the creek has a meandering, riffle-pool form. In some areas, the channel has cut into the Queenston shale formation. The channel is generally connected to the floodplain although there is intermittent entrenchment.

2.4.2 Fourteen Mile Creek and its Tributaries Fourteen Mile Creek and its tributaries were walked between Lake Ontario and Dundas Street West (Reaches 1-15 and 72-76e). Downstream of the Queen Elizabeth Way (QEW), the creek is generally contained within a limited corridor with residential, commercial, and industrial land uses adjacent. The majority of the creek has been straightened or hardened with bank treatments including armourstone and gabion basket revetments. Floodplain access in this area is limited. Upstream of the QEW, the main branch of Fourteen Mile Creek is contained within a wide, forested valley. The channel has cut into the Queenston shale formation and follows a meandering planform with riffle-pool features. At various points the channel contacts the valley toe and erosion scars have developed. However, development is generally set back from the top of the valley and therefore, these scars do not pose an immediate threat to existing development. Beaver dams were found throughout this system. Tributaries and reaches upstream of Upper Middle Road are contained within more limited corridors and have often been altered during land development. Some reaches have been straightened and hardened while others have been realigned with the valley corridor excavated and re-vegetated. Some reaches have been buried in storm sewer conduits while others have been converted to stormwater management facilities.

2.4.3 McCraney Creek McCraney Creek was walked from Lake Ontario to Fourth Line and from the QEW to Dundas Street (Reaches 17-19b and 21-22). Downstream of the QEW McCraney creek passes through the Appleby College grounds, alongside Fourth Line, and through residential areas. The channel is straightened and mildly entrenched with a fractured shale bed. Large portions of the stream pass through private property. Upstream of the QEW McCraney Creek is contained in a moderately-sloped, forested valley surrounded by commercial and residential land uses. Where the channel contacts the valley wall there is localized bank protection. The stream has been channelized upstream of Pilgrims Way and becomes more entrenched with constructed grade control.

2.4.4 Taplow Creek Taplow Creek was walked from the confluence with Glen Oak Creek to Upper Middle Road (Reaches 24a-28). Downstream of the QEW the creek is a drainage swale passing through



industrial areas until reaching a straightened and hardened channel at the confluence with Glen Oak Creek. Upstream of the QEW the channel passes through a wide, forested valley where there is evidence of planform adjustment in Reach 26. Localized bank erosion occurs where the channel contacts the valley wall. As the valley narrows, the vegetation becomes scrubbier and eventually gives way to cattails and shrubs. Upstream of Pilgrims Way the channel is straightened with well-established plantings such as forsythia and alders.

2.4.5 Glen Oak Creek Glen Oak Creek was walked from the confluence with McCraney Creek to Upper Middle Road (Reaches 29a-32 and 96-97). Downstream of the QEW the channel is straightened and hardened in many stretches with gabions that are starting to slump and empty. The stream is mildly entrenched to entrenched with residential yards backing onto the bank. Downstream of Speers Road the creek is impassable due to overgrown vegetation. Upstream of the QEW, Glen Oak Creek passes through a mild-to-moderately sloped valley with scrubby vegetation to mature forest. Channel down-cutting is evident from perched culverts and falling trees. Stretches of the channel are straightened and hardened with concrete block revetment. Constructed grade control is present.

2.4.6 Shannon’s Creek Shannon’s Creek was evaluated from Neyagawa Boulevard to River Glen Boulevard (Reaches 92-94). The downstream reach (Reach 92) is contained within a steep slope valley surrounded by mature forest and residential development. Much of the channel has been hardened with gabion baskets that are failing from the channel down-cutting into the Queenston shale. Previous assessments have identified this reach as an area of concern. Upstream reaches of the channel pass through scrubby vegetation and mowed parkland where the channel is poorly defined and intermittent.

2.4.7 Munn’s Creek Munn’s Creek was assessed from Culham Street to Dundas Street (Reaches 33-37 and 77-81). Downstream of Upper Middle Road, the creek is characterized by active erosion and channel hardening measures in the form of gabion baskets, armourstone, and riprap bank protection. Many of the bank treatments are failing. Riparian vegetation includes several invasive species such as garlic mustard (Alliara petiolata), Manitoba maple (Acer negundo), and common buckthorn (Rhamnus cathartica). Landowner encroachment and yard waste dumping is impacting the channel. Upstream of Munn’s Avenue the creek is a constructed channel that passes through more recent residential development and has access to a wide floodplain. The upper reaches are a marsh wetland of cattails and phragmites with intermittent flow and no identified erosion risks.

2.4.8 Morrison Creek West Branch West Morrison Creek was walked from Upper Middle Road to Glenashton Drive (Reaches 82-86). The area upstream of Glenashton Drive is now stormwater management ponds. Reaches 36-



38 were omitted as they are currently undergoing an Environmental Assessment. West Morrison Creek is characterized by a wide floodplain with limited impacts to surrounding residential development. Channel hardening has occurred in some areas and downstream of Glenashton Drive (Reach 86), the channel is engineered. A beaver dam was impacting flow upstream of Upper Middle Road.

2.4.9 Morrison Creek East Branch East Morrison Creek was evaluated from the Morrison-Wedgewood Diversion Channel to Postridge Drive (Reaches 39-45). The creek is contained in a steep-sloped valley with frequent valley wall contact and down-cutting into the Queenston shale. The channel is hardened in various places with gabion basket treatments, most of which are failing. In Reach 40 the gabion baskets are being buried by sediment from slope erosion and at the top of slope, rear yard fences are leaning. Fallen trees and knickpoints are present throughout. East Morrison is recommended for reach-based erosion works.

2.4.10 Morrison Creek Main Branch Lower Morrison Creek was evaluated from Lake Ontario to the South Service Road (Reaches 46-52a). Portions of Lower Morrison Creek are on private property and were not walked. The creek has moderately-sloped to steep banks and connection to the treed floodplain varies from well-connected to moderately entrenched. Channel hardening has occurred intermittently, with many treatments starting to fail. There are some leaning residential fences where the creek contacts backyards. In Reach 52, recent riparian plantings are in need of maintenance.

2.4.11 Falgarwood Creek Falgarwood Creek was walked from the Morrison-Wedgewood Diversion Channel to Gainsborough Drive (Reach 54). The creek is contained within a steep valley bordered by residential land use. Upstream of Falgarwood Drive the channel has been engineered with armourstone walls and grade control throughout.

2.4.12 Wedgewood Creek Wedgewood Creek was assessed from Lake Ontario to Upper Middle Road (Reaches 55a-61 and 95). Downstream of the QEW, sections of Wedgewood Creek are straightened and hardened with stone walls, gabion baskets, and bank protection. The creek corridor passes through residential areas with gentle slopes and is bordered by a mixture of manicured lawns, open space, and narrow forested areas. Upstream of the QEW, the creek empties into the Morrison Wedgewood Diversion Channel at its downstream extent. Upstream of this, the creek is contained within a steep valley with the channel bed cutting into the Queenston shale. Reach 59 underwent recent restorative work with bank treatments that have enhanced natural processes and reduced risk from erosion. Further upstream the creek narrows and the valley slope becomes more moderate with bank treatments consisting of failing gabion baskets.

2.4.13 Joshua’s Creek Joshua’s Creek was evaluated from Lake Ontario to Dundas Street (Reaches 62-68 and 87-89aa). Downstream of the QEW, the channel largely exhibits a meandering riffle-pool form within a



gentle-to-moderately sloped valley, passing through residential areas buffered by mature forest. The reaches immediately downstream of Cornwall Road are straightened and hardened with gabion basket treatments. Above the QEW the channel again follows a meandering riffle-pool form with access to a wide floodplain and limited risk to private properties. Some steeps slopes are eroded but pose no immediate risk due to the wide buffer. The channel has been hardened in some spots, most notably near a new stormwater outfall. Mature deciduous forests and meadows dominate the riparian areas.

2.4.14 Clearview Creek Clearview Creek was walked from Winston Churchill Boulevard to Cornwall Road (Reaches 90 and 91). The channel has been realigned and constructed with riffle-pool sequences. New riparian plantings provide some woody vegetation as the creek passes through a grassy floodplain between residential and industrial land uses. Upstream of the railroad tracks the channel is straightened and constrained within an industrial corridor.

3 CREEK ASSESSMENT METHODOLOGY

3.1 Overview Field walks were conducted by a team of 2 Aquafor staff. The geomorphic condition of the watercourse was assessed as was the risk of erosion to surrounding infrastructure and property. RGAs, RSATs, reach evaluation forms, and erosion site evaluation forms were filled out during the field walks and a photographic inventory of existing channel conditions was collected. Incident observations were noted on the field mapping. Additionally, conditions of pedestrian crossings and storm sewer outfalls were noted as were the locations of debris jams. Subsequent to the field walks, the collected data were compiled. A review of the erosion site evaluations was completed to ensure standardization between sites. Overall prioritization of watercourse works was then determined. The sections below describe the creek assessment methodology in more detail.

3.2 Geomorphic Assessment Existing geomorphic conditions for the Town’s watercourses were evaluated during the field walks. Assessments were completed on a reach basis with rapid assessment tools used to provide an indication of channel stability and stream health. These tools are outlined below. Additional data collection included representative channel dimensions, substrate composition, erosion protection measures, floodplain access, and a reach description. The results from the geomorphic assessment were referenced but not used directly in the erosion prioritization. As noted in the 2010 erosion report, RGA and RSAT scores do not provide a direct measure of risk to property, infrastructure, and public safety. As such, the reaches showing the highest geomorphic instability from the RGA results are not necessarily the reaches which should be prioritized for channel works. Additionally, the field ranking system included “stress” and “erodibility” categories which can act as a surrogate measure of channel degradation and widening. As noted in the 2010 report, channel degradation and widening are processes which may pose a risk to infrastructure.



Although the results from the assessment tools were not used directly in the prioritization of sites, they were valuable in providing an indication of the dominant channel processes and allowing for a greater understanding of the reach within the overall fluvial system. As such, these results were used to confirm the prioritization of erosion sites (i.e. dominant processes of degradation and widening may pose risks to infrastructure in an urban settings) and during the development of conceptual restoration for costing purposes.

3.2.1 Assessment Tools As with previous studies, the rapid assessment tools used during the field walks were the Rapid Geomorphic Assessment (RGA) and the Rapid Stream Assessment Technique (RSAT). As noted in the 2010 study, the extent of the reaches evaluated has varied slightly over the years from 2001 to the present. In this study, reaches which were engineered to remain fixed in place were omitted from the RGA and RSAT as they have been designed to resist the adjustment processes described by the RGA and stream characteristics do not correspond to descriptions provided in the RSAT form for channel stability and scouring/deposition. The Rapid Geomorphic Assessment The RGA protocol uses visual indicators to determine whether a given stream is stable or in adjustment. Stability of the channel is determined by adjustments in slope; the bed elevation may be increasing due to sediment deposition (aggradation) or decreasing due to bed erosion (degradation). Consideration of increases in bank to bank width (widening) and indicators suggesting a change in the planform regime (planimetric form adjustment) are also part of the assessment. Based on the results of the RGAs, reaches were classified as “stable”, “transitional”, or “in adjustment” depending on the stability index value as described in Table 3.1. Table 3.1: Rapid Geomorphic Assessment Descriptions based on Index Value

Stability Index Value Stability Class Description

0 - 0.25 In Regime

Channel morphology is within the expected range of variance for stable channels of similar type. Channels are in good condition with minor adjustments that do not impact the function of the watercourse.

0.25 – 0.40 Transitional

Channel morphology is within the expected range of variance but with evidence of stress. Significant channel adjustments have occurred and additional adjustment may occur.

0.40 – 1.0 In Adjustment

Metrics are outside of the expected range of variance for channels of similar type. Significant channel adjustments have occurred and are expected to continue.

Source: Ontario Ministry of the Environment (2003)



The Rapid Stream Assessment Technique The RSAT provides an appraisal of in-stream habitat as well as channel morphology. Channel reaches are evaluated on the basis of six factors: channel stability, channel scouring/sediment deposition, physical instream habitat, water quality, riparian habitat conditions, and biological indicators. The sum of the six factors is used to classify the stream quality of the reach as “excellent”, “good”, “fair”, or “poor” as summarized in Table 3.2. Table 3.2: RSAT Stream Quality based on Score

Score Stream Quality 42-50 Excellent 30-41 Good 16-29 Fair <16 Poor

Source: Galli (1996)

3.3 Erosion Risk Assessment Field walks were conducted to assess the condition of Town watercourses and infrastructure. Erosion sites were identified which posed risks to property, infrastructure, or existing channel treatments. In addition to demarcation of erosion sites, knick points and debris jams were identified and mapped and storm sewer outfalls and pedestrian crossings were evaluated for required maintenance works.

3.3.1 Inventory of Creek Erosion The extent of the watercourse field walks is shown on Figure 2.2 and Figure 2.3 and corresponds to the same watercourses that were assessed previously in the 2010 study, with the exception of areas that have subsequently been developed and converted to stormwater infrastructure. During the field walks, a photographic inventory of creek conditions was collected. The locations of the photographs were marked on the field mapping while the photographs themselves were taken with a camera using GPS. Data collected during the field walks included erosion sites, channel treatments, profile knick points, debris jams, and observations. Observations were marked on field maps and GIS shape files were created subsequently. Forms for erosion sites and reach characteristics were also completed in the field. Sample data collection forms are included in Appendix B. Erosion site forms included typical channel dimensions, observations upstream and downstream, adjacent land use, riparian vegetation, items observed to be at risk, a site description, and a field ranking. The field ranking included six criteria and was based on the system used in 2010. The six criteria were as follows:

• Distance to risk, • Stress, • Erodibility, • Resource type, • Extent of damage, and • People at risk.



These categories are described in further detail below along with tables summarizing the values assigned in the scoring of erosion sites. Distance to Risk Within this category, the distance between the erosion and the item at risk was evaluated. Erosion that was closer to the item at risk received a higher score in this category. Values for the scoring are presented in Table 3.3. Table 3.3: Scoring for Distance to Risk Criterion Distance to Risk Score

>30 m 2 20-30 m 4 10-20 m 6 0-10 m 8

Stress Site conditions were inspected to rank the degree of shear stress exhibited at the erosion site. Indicators of higher shear stresses at a given site (i.e. evidence of erosion from flows overtopping the bank) received a higher score than evidence of flow contained within the channel. Details for the scoring are shown in Table 3.4. Table 3.4: Scoring for Stress Criterion

Stress Score Flow within channel 5 Bank piping/seepage 10

Erosive flow 15 Overtopping flow 20

Erodibility The erodibility of the materials at a given site was evaluated visually based on an inspection of site conditions. Sites showing evidence of some material movement were ranked lowest. Sites with bed or bank treatments or structures showing evidence of material defects, backfill, or undermining were scored progressively higher (see Table 3.5). In this manner, sites with a greater likelihood of failure were ranked highest. Table 3.5: Scoring for Erodibility Criterion

Erodibility Score Material movement 5

Material defects 10 Backfill exposed 15

Undermining 20 Resource Type The type of resource at risk at each erosion site was also used as a criterion to rank the sites. Resources that posed a greater threat to public safety or infrastructure safety received a higher



score in this category. An additional entry entitled “private property” was added to the 2010 list and given a score of 10. Details of the score are presented in Table 3.6. Table 3.6: Scoring for Resource Type Criterion

Resource Type Score Vegetation 2

Rip Rap/ Gabion baskets 4 Armourstone 6

Bed or Bank Protection 8 Private Property 10

Public Transportation 11 Parking Lot 14

Private Crossing 16 Sewers 19 Roads 21

Bridges 24 Buildings 24

Extent of Damage The physical extent of damage at each erosion site was visually assessed. Sites with damage covering a larger area were deemed to rank higher than those with damage covering a smaller area. As such, the scoring for each site was determined based on the numbers show in Table 3.7. Table 3.7: Scoring for Extent of Damage Criterion

Extent of Damage Score 0-100 m2 2

101-200 m2 4 201-300 m2 6

>300 m2 8 People at Risk At each erosion site, the surrounding area was observed to assess the number of people likely to be affected by a failure of the affected resource at the site. In general, the greater the number of people affected, the higher the score for this category (see Table 3.8). Table 3.8: Scoring for People at Risk Criterion Number of People at Risk Score

1-4 2 5-9 4

10-24 6 25+ 8



3.3.2 Inventory of Outfalls, Pedestrian Crossings, and Debris Jams During the field walks, the condition of existing storm sewer outfalls, pedestrian crossings, and debris jams was documented. For the storm sewer outfalls and pedestrian crossings, the condition of the infrastructure was noted on the mapping along with maintenance or monitoring requirements. For debris jams, the severity of the debris jam was noted on the mapping.

3.4 Evaluation and Prioritization of Risk Locations Following completion of the field assessments, collected data were reviewed. Erosion site evaluations were compared and adjusted, as needed, to ensure a standardized evaluation across the watercourses. For erosion sites with suspected risk to buried infrastructure (i.e. sanitary sewers and water mains), confirmation of the presence and location of the infrastructure was requested and received from Town staff. As with the 2010 study, recommended works were divided into categories. The category for areas of concern within private property was removed since the Town does not generally pursue restoration works on private property. Exceptions may be made where land can be purchased or permanent easements established. An additional category, “areas of concern associated with road crossings”, was added. Thus, erosion site categories used in the current assessment are as follows:

1. Priority reach long areas of concern,

2. Priority localized areas of concern,

3. Areas of concern associated with road crossings, and

4. Area of concern recommended for monitoring.

The list of prioritized works for the Town includes reaches from the first two categories. The first category consists of reaches, or a series of reaches, where extensive works are required to mitigate risks to infrastructure and private property. Sites in the second category are more localized in nature with repairs possible on a selective basis rather than on a reach-scale. Sites included in the third category are associated with deficiencies at culverts or bridges. Sites within the monitoring category do not pose an immediate risk to infrastructure or property but may do so in future. As such, they should continue to be monitored to identify any worsening of the risk.

3.5 Rehabilitation Techniques A variety of remediation alternatives are available to address the erosion concerns identified in this study. The alternatives range from soft techniques such as bioengineering to harder techniques such as roundstone or armourstone bank and/or bed treatments. The appropriate remediation method for each erosion site will depend on a number of factors including space, landownership, channel boundary conditions, hydraulics, and cost. Preferred remediation alternatives will be determined during individual Environmental Assessments (EAs) to be undertaken for each of the identified sites. The following sub-sections provide examples of possible remediation approaches, their purpose, and the type of treatment they involve. The approaches outlined are examples of remediation that will promote channel stability and/or habitat, and can reduce the risk to public health and



safety caused by threats to, or degradation of, Town infrastructure. The applicability of these techniques should be further considered during the EA process.

3.5.1 Armourstone Wall Protection Armourstone wall protection consists of a free standing stone structure with large blocks of stone layered vertically and offset from one another. The geotextile material and free-draining gravel placed behind the stone prevent soil movement into or through the stones and allow water to drain. These structures can be used within reaches which experience lateral channel adjustment, have highly erodible banks, or a step bank grade and where space is constrained such that natural planform adjustment is not possible. The armourstone walls protect the bank toe and bank face and are able to withstand high design velocities (approximately 5.0 m/s). Details for a typical armourstone wall are illustrated in Figure 3.1.

Figure 3.1: Typical Detail of Armourstone Wall

3.5.2 Vegetated Geogrid/Coir Mat Vegetated geogrid (or coir mat) treatments are used to minimize erosion and can also improve habitat within the restoration area. These structures can withstand relatively high design velocities (~ 2.9 m/s) and can be constructed along very steep, eroded banks. Vegetative cuttings should be sufficiently long to make contact with the eroded bank and project from the geogrid



structure. The root systems of the live cuttings eventually penetrate the grids resulting in one cohesive mass. Rock should be placed at the toe of the slope and extend above the low-flow waterline. Typical details for the design of a vegetated geogrid are illustrated in Figure 3.2.

Figure 3.2: Typical Detail of Vegetated Geogrid

3.5.3 Live Crib Wall Live crib walls are used for slope and stream bank protection. These structures consist of a hollow, box-like framework of untreated logs or timbers filled with rip rap and alternating layers of soil and live branch cuttings. They can be used to protect banks against toe scour and undermining. Immediate protection is provided by the log framework and long-term durability is provided by the live branch cuttings. Crib walls should not be used where the channel bed is severely eroded or where undercutting is likely; as well, high banks (greater than 3 m in height) should be avoided due to the fact that crib walls cannot resist large lateral earth stresses (Heaton et al., 2002). Typical details for the design of a live crib wall are illustrated in Figure 3.3.



Figure 3.3: Typical Detail of Live Crib Wall Source: Maryland Department of the Environment (2000)

3.5.4 Live Staking Live staking involves the insertion of live, woody, rootable plant cuttings into stream banks to encourage vegetative growth. This vegetation establishes a root mass which helps to bind, stabilize, and reinforces the stream bank. Live stakes can slow water velocities, trap sediment, and control erosion. Live staking is only considered to be a preventative measure and should be applied where it is desirable to slow further erosion. However, this method can be used in conjunction with other restoration techniques such as vegetated geogrids or vegetated rip rap. Live stakes should be planted on streams with low to moderate flow fluctuations and planted where sufficient sunlight exists. Typical details for the use of live staking are illustrated in Figure 3.4.



Figure 3.4: Typical Detail of Live Staking Source: Maryland Department of the Environment (2000)

3.5.5 Rib Structures Rib structures are used to provide grade control in watercourses with channel bed degradation. They may also be used to maintain the bed grade where infrastructure crosses under the channel. Ribs structures are typically composed of large key stones which are sized to ensure they are stable under high flow conditions within the watercourse. Additional well-graded material is placed around the key stones. Aquatic habitat may be enhanced by stepping the key stones in cross-section to create a low flow channel across the rib structures. A typical rib structure is shown in profile in Figure 3.5.



Figure 3.5: Typical Profile Detail of Rib Structure

3.5.6 Deflectors Stream deflectors are structures which limit channel width and accelerate normal flows through the constricted section. They can be used in over-widened watercourses to provide a narrower, deeper low-flow channel. Deflectors are typically constructed of rock and logs and can be used singly or in series. Deflectors can be used to direct base flow away from channel banks and, under certain conditions, can create scour pools which will enhance fish habitat. Deflectors should not be used in unstable streams and they are ineffective in bedrock channels. As well, deflectors should not be used in reaches which exceed a gradient of 3% or in channels with large sediment and/or debris loads. A typical log deflector is shown in Figure 3.6.



Figure 3.6: Typical Detail of Deflectors Source: Maryland Department of the Environment (2000)

3.5.7 Terraced Floodplain A terraced floodplain can help to reduce channel erosion capacity for higher-flow events by allowing flows to spill out of the channel. Additional width and higher surface roughness in the floodplain achieve the reductions in the watercourse velocities and shear stresses. Construction of a terraced floodplain would only be possible in areas with open space available adjacent to the channel. As such, the applicability of this technique is limited in constrained urban areas.



Figure 3.7: Typical Terraced Floodplain Detail

3.5.8 Channel Realignment Channel realignment can be used where the existing channel location poses a risk to infrastructure or property. Realigning the planform of the channel can increase the lateral distance between the channel and the item of concern thereby reducing the risk. However, the availability of adjacent space limits the applicability of this technique. As well, initial terrestrial habitat impacts may be high depending on the required vegetation clearing and removal for the new channel alignment.

Figure 3.8: Example of Channel Realignment for Infrastructure Protection

3.5.9 Summary of Advantages and Disadvantages The advantages and disadvantages of the rehabilitation techniques presented in the preceding sections are summarized in the table below.



Table 3.9: Advantages and Disadvantages of Rehabilitation Techniques

Rehabilitation Technique

Advantages Disadvantages

Armourstone Wall

• Is suitable for steep and/or eroded banks

• Is suitable where space is constrained or fixed-in-place planform is desired

• Is resistant to velocities up to about 5.0 m/s

• Requires minimal maintenance

• Requires installation by heavy machinery

• Provides limited aquatic and terrestrial habitat

• Does not allow for changes in planform over time

Vegetated Geogrid

• Provides aquatic and terrestrial habitat

• Resistant to velocities up to about 2.9 m/s once vegetation has established

• Is suitable for steep and/or eroded banks

• Requires minimal maintenance

• Requires time for vegetation to establish

• Can experience impeded growth under heavy over-storey

Live Crib Wall • Provides immediate protection (log frame) and long-term protection (established vegetation)


• Is suitable where space is constrained

• Can be installed near vertical

• Is unsuitable on banks >3 m in height

• Is unsuitable where bed is severely eroded or where undercutting is likely

• Is labour-intensive during installation

• Can experience impeded growth under heavy over-storey

Live Staking • Provides velocity reduction, bank stabilization, and help to trap sediment

• Is suitable for use in conjunction with other restoration measures


• Provides a preventative measure for bank erosion protection (not a restoration measure in and of itself)

• Requires sunlight for vegetation growth

• Takes time for vegetation establishment (1-3 years)

Rib Structures • Provide grade control where bed degradation is an issue

• Provide protection to buried infrastructure crossings

• Require placement of large material in the channel for stability

• Limits the ability to allow for changes to planform over time



Rehabilitation Technique

Advantages Disadvantages

Deflectors • Direct flow away from area of concern

• Provide channel grade control • Can be used to limit channel

width and/or create scour pools for aquatic habitat

• Provide preventative measures for bank protection (not a restoration measure in and of itself)

• Are unsuitable for unstable watercourses, reaches with gradients >3%, or channels with high sediment and/or debris loads

• Are ineffective in bedrock channels

Terraced Floodplain

• Provides reduction in velocities and shear stresses

• May be used in conjunction with bioengineering treatments

• Requires large amount of space • May reduce cover on adjacent

buried utilities

Channel Realignment

• Often allows new channel to be constructed entirely in the dry without the need for flow diversion

• May be used in conjunction with bioengineering treatments

• Increases long-term channel stability

• Requires large amount of space • Results in loss of existing

aquatic and terrestrial habitat

3.6 Additional Opportunities In addition to the rehabilitation techniques listed in Section 3.5, opportunities not directly related to individual erosion sites were also identified during the field walks. These opportunities included establishment of vegetative buffers and landowner education. Implementation of these opportunities can help to reduce future erosion and flooding-related impacts within watercourses and improve overall watershed health. In some area, manicured lawns were found adjacent to the channel. In other areas, plant diversity within the riparian zone was limited as was the width of the buffer. Increasing the width, as well as the variety and diversity of native plant species within the riparian buffer will provide cover and habitat for fish, insects, and invertebrates along the watercourse. Deep-rooted vegetation planted along the banks will also help to stabilize the creek banks, which in turn will help to limit bank erosion. Landowner education regarding these benefits will be needed to encourage owners to plant native species and establish a healthy riparian buffer on their properties. Resident education will also be needed in areas where the Town may decide to establish improved riparian buffers in parks. An understanding of the benefits may help residents to adjust to the new look of the parks. Another opportunity for landowner education exists with respect to the disposal of yard waste. Piles of discarded yard waste were found in numerous locations in watercourse corridors



throughout the Town. Disposal of yard waste into watercourse corridors can cause debris jams within the channel and impact flow conveyance, which could potentially cause channel erosion and flooding. Due to the observed widespread nature of this issue, it is recommended that the Town implement a program of landowner education on this matter. The program should also emphasize the fact that Halton region provides a bi-weekly curb-side yard waste removal service from the end of March to early December at no additional cost to residents (Halton Region, 2015). Acceptable items for yard waste collection include leaves, sticks and twigs, tree trimmings, decorative cornstalks, fallen fruit from trees, yard and garden trimming, and pumpkins. Grass clippings cannot be collected as yard waste but can be “grasscycled” by leaving them on the lawn. Additional information can be obtained from the Halton Region website.

4 CREEK ASSESSMENT RESULTS AND RECOMMENDATIONS

4.1 Geomorphology Evaluation Results The existing geomorphic conditions of the Town’s watercourses were documented during the field assessments. Appendix A presents a summary of reach characteristic as well as the RGA and RSAT evaluations which provide an indication of channel stability and stream health, respectively. The reaches with the 20 highest RGA stability index scores are presented in Table 4.1 below. As noted previously, the RGA score does not provide a measure of the risk to property, infrastructure, and public safety. Thus, alone, the RGA score is not a means of prioritizing channel restoration works. However, it can be noted that most of the reaches listed in Table 4.1 have been identified in the subsequently discussed areas of concern. The exceptions are Wedgewood Creek Reaches 59 to 61 and Munn’s Creek Reach 77. Although Reach 59 was recently stabilized, the channel slope in this reach is quite steep, resulting in continued erosion. However, erosion is expected in this system and is not posing an immediate risk to adjacent properties. Works are in the design phase at Reach 60 and Reach 61 is owned by the Region of Halton. Within Reach 77, large woody debris is prevalent as are points of valley toe contact. Although erosion was observed throughout the reach, it did not pose an immediate risk to recreational trails or private property. In general, areas of concern are more likely to exhibit geomorphic instability and the results of the geomorphic assessment are valuable in providing an understanding of the processes at work in the reach. The information gathered during the geomorphic assessment can be used further in the development of restoration approaches for priority erosion sites.



Table 4.1: Reaches with Highest RGA Stability Index Score

Watercourse Reach RGA RSAT

Stability Index Classification Dominant

Process Total Verbal Ranking

Shannon's Creek R92 0.68 In Adjustment Degradation 14 Poor Wedgewood Creek R59 0.67 In Adjustment Widening 18 Fair Wedgewood Creek R60 0.58 In Adjustment Widening 23 Fair Wedgewood Creek R61 0.57 In Adjustment Widening 17 Fair

Munn's Creek R33 0.50 In Adjustment Widening 27 Fair McCraney Creek R21 0.50 In Adjustment Degradation 16 Fair Shannon's Creek R93 0.50 In Adjustment Degradation 17 Fair

Munn's Creek R35 0.50 In Adjustment Widening 22 Fair Glen Oak Creek R97 0.49 In Adjustment Aggradation 14 Poor McCraney Creek R18 0.49 In Adjustment Widening 25 Fair

Munn's Creek R78 0.48 In Adjustment Widening 18 Fair Morrison Creek R43 0.47 In Adjustment Widening 22 Fair Morrison Creek R45 0.45 In Adjustment Widening 21 Fair Morrison Creek R49 0.44 In Adjustment Widening 24 Fair Morrison Creek R39 0.44 In Adjustment Widening 19 Fair Morrison Creek R44 0.43 In Adjustment Widening 23 Fair Munn's Creek R77 0.43 In Adjustment Widening 20 Fair

Morrison Creek R40 0.43 In Adjustment Widening 19 Fair McCraney Creek R17 0.42 In Adjustment Widening 25 Fair Morrison Creek R42 0.41 In Adjustment Widening 23 Fair

Priority Reach Long Area of Concern Priority Localized Area of Concern Area of Concern Recommended for Monitoring A summary of the number of reaches exhibiting each of the dominant channel processes is presented in Table 4.2 Channel widening is the most common dominant process. This result is typical of urban channels where modified hydrology results in higher, flashier storm flows. Channel width increases to accommodate the more frequent higher flows. Thus, as expected, Oakville’s watercourses exhibit characteristics of urbanization within the watersheds. Widening, and channel degradation, are also often associated with areas of concern in urban settings as these processes can pose a risk to infrastructure within the corridor, such as storm sewer outfalls and sanitary sewers.



Table 4.2: Summary of Reach Dominant Processes

Dominant Process Number of Sites

Aggradation 16 Degradation 17 Widening 48

Planform Adjustment 3

4.2 Priority Areas of Concern Priority areas of concern were identified based on both observed erosion risks and the geomorphic assessment of the subject reach. The priority areas of concern were divided into 4 categories:

1. Priority reach long areas of concern,

2. Priority localized areas of concern,

3. Areas of concern associated with road crossings, and

4. Area of concern recommended for monitoring.

The sites in each category are summarized in the tables below. The locations of all priority areas of concern are shown in Figure 4.1. Table 4.3: Priority Reach Long Areas of Concern Rank Watercourse Reach Description

1 East Morrison Creek

R39-45

Bed and bank protection measures are failing throughout these reaches. Storm sewer outfalls are in poor condition and bank erosion is posing a risk to recreational crossings and trails. These reaches were a high priority in the 2010 study.

2 Munn's Creek R33-35 Bank protection measures are failing and eroding banks are

putting recreational trails and private property at risk.

3 Joshua's Creek R67-68

These reaches are lined with gabion basket bank protection which is in poor condition. A concrete encasement for a Region of Halton sanitary sewer crosses the creek.



Table 4.4: Priority Localized Areas of Concern Rank Watercourse Reach Description

1 McCraney Creek R21

Channel down-cutting has resulted in exposed bridge footings and perched concrete bed conditions at Lakeshore Road and Rebecca Street. An unidentified metal conduit is exposed on the west bank upstream of Lakeshore Road.

2 Glen Oak Creek R32a

A knick point under the Speers Road crossing may be putting water main and sanitary sewer infrastructure at risk. Channel down-cutting at Pinegrove Road may be putting water main and sanitary sewer infrastructure at risk. Gabion basket revetments are also in poor condition.

3 Fourteen Mile Creek R5

Gabion basket bank treatments are present throughout the reach and are intermittently emptying. One localized gabion basket failure was identified and poses a risk to private property.

4

Glen Oak Creek R30 Bank erosion and failing gabion basket treatments pose a risk

to private property. McCraney Creek R22 Gabion basket treatments are failing at the downstream end of

the Fourth Line culvert.

5 Fourteen Mile Creek R5a Bank erosion on an outside bend poses a possible threat to

Region of Halton sanitary sewer infrastructure.

6 McCraney Creek R17 Channel down-cutting and bank erosion has resulted in a

perched culvert and risk to a recreational trail. Table 4.5: Areas of Concern associated with Road Crossings Rank Watercourse Reach Description

1 Falgarwood Creek R54a Channel down-cutting has results in a perched condition at the

Falgarwood Drive culvert outlet.

2 Wedgewood Creek R95 The culvert at Amber Crescent is in poor condition. Bank

protection is in poor condition at Duncan Road. 3 Wedgewood

Creek R58 Failing rip rap bank protection is resulting in a reduction in

culvert capacity at Drummond Road.



Table 4.6: Areas of Concern Recommended for Monitoring Rank Watercourse Reach Description

1 Glen Oak Creek

R29a Bank erosion upstream of Wyecroft Road poses a risk to a fence and yard and parking lot/shipping area.

2 Fourteen Mile Creek

R12 Valley wall erosion poses a risk to a recreational trail at the top of slope. Trail should be moved. Continue to monitor valley wall erosion.

3 Shannon's Creek

R92 & 93

Down-cutting of the channel has resulted in undermined, slumping conditions for intermittent gabion basket bank treatments. Valley wall erosion may pose a threat to recreational trails at the top of slope. These reaches were a high priority in the 2010 assessment.

4 Wedgewood Creek R56

Gabion basket bank protection is failing and poses a risk to private property. A privately constructed armourstone wall is failing and poses a risk to a storm sewer outfall.

5 Fourteen Mile Creek R76e

Woody debris and loss of vegetation has resulted in the development of multiple channels under the Colonel Williams bridge.

6 Lower Morrison Creek

R51 Bank erosion and failed gabion basket treatments pose a risk to private property.

7 Wedgewood Creek

R55 Bank erosion has resulted in exposure of a lawn sprinkler system.

8 Sheldon Creek R69

Concrete bed and bank protection is undermined and the concrete is spalling. Channel restoration should be completed with shoreline works. It should also be noted that the constriction at the outlet caused significant backwater flooding during August 4, 2014 storm event causing water to flow overland and erode a section of shoreline to the east.

9 Fourteen Mile Creek R13 Bank erosion on an outside bend is migrating towards a

recreational trail.

10 Sheldon Creek R71

Bank erosion is migrating towards a recreational trail. Bank erosion in this area may have been exacerbated by August 4, 2014 storm.

11 Fourteen Mile Creek R3 Gabion basket bank protection is failing and valley wall is

eroding where unprotected at toe.


R50 Bank erosion poses a risk to private property.


R49 Concrete block bank protection is leaning and bank erosion poses a risk to private property.

14 Glen Oak Creek R29 Concrete block revetment downstream of Monks Passage is

undermined and unravelling.



Rank Watercourse Reach Description

15 Fourteen Mile Creek R6a Concrete block revetment downstream of Brays Lane is


16 Munn's Creek R79 Backfill has eroded behind armourstone bank protection.

17 Glen Oak Creek R96-97 Unravelling concrete block revetment and actively migrating

channel planform may pose a risk to private property.

18 McCraney Creek R18 Concrete block revetment downstream of Pilgrims Way is


19 Taplow Creek R27 Concrete block revetment is undermined and unravelling.

20 West Morrison Creek

R83 Concrete block revetment downstream of River Oaks Boulevard is undermined and unravelling.

21 Glen Oak Creek R32 Gabion basket bank protection upstream of Pinegrove Road is

starting to fail.

22 Fourteen Mile Creek R10 Gabion basket bank protection and grade control is starting to

fail.

23 Joshua's Creek R64 Bank erosion and armourstone wall failure pose a risk to

recreational trails.

24 Wedgewood Creek R57 Armourstone bank treatment is becoming outflanked adjacent

to a recreational trail.

25 Fourteen Mile Creek R75b Valley wall erosion poses a risk to a recreational trail.

26 Munn's Creek R78 Valley wall erosion may pose an eventual risk to Munn’s

Creek Park at the top of slope.

27 Taplow Creek R25-26 Concrete block revetment is unravelling upstream and

downstream of Pilgrims Way.

28 Glen Oak Creek R29b Concrete block revetment downstream of Monastery Drive is


29 Joshua's Creek R89a Gabion basket bank protection is in poor condition and may

pose a risk to conveyance if failure occurs.



Figure 4.1: Locations of Priority Areas of Concern



4.3 Reach Long Areas of Concern Reach long areas of concern are sequential watercourse reaches exhibiting a high degree of erosion throughout. Erosion sites are grouped to allow for a reach-based examination of the system and restoration approach. The 2010 study identified 3 reach long areas of concern:

• West Morrison Creek, Reaches 36-38

• Shannon’s Creek, Reaches 92-93, and

• East Morrison Creek, Reaches 39-45. The first priority from the 2010 study is currently being addressed through the Environmental Assessment process. The second-ranked priority was re-ranked in the current study as there are setbacks from the top of valley to private property. Other reaches pose greater risks to infrastructure and property. Additionally, 2 sites were added to the list for the current study: Munn’s Creek Reaches 33-35 and Joshua’s Creek Reaches 67-68. Descriptions of each of the areas of concern are provided below while maps and summary sheets are included in Appendix C.

4.3.1 East Morrison Creek, Reaches 39-45 Bed and bank protection measures are failing throughout these reaches. These observations are supported by the results from the RGA which show that Reaches 39-45 are “in transition” with the dominant channel process being widening. Evidence of degradation was also observed and the channel has cut into Queenston shale in many locations. Gabion baskets revetments have become undermined through channel bed lowering and outflanked at upstream and downstream extents through channel widening. The wire mesh is in poor condition and stone fill is emptying intermittently. At the downstream end of the area of concern, these gabion treatments have also become buried through slope erosions. Rip rap and armourstone revetments are also in poor condition due to outflanking associated with channel widening and slumping associated with channel bed degradation. Failure of these treatments poses a risk to the adjacent recreational trail and bridges. The watercourse contacts the valley toe in numerous locations throughout the area of concern with valley wall scars developing. In some areas, valley wall erosion may pose a threat to private property or recreational trails at the top of the valley. Additionally, yard waste dumping was noted in several locations on the valley wall and will contribute to slope instability. Storm sewer outfalls within the area of concern are also in poor condition. At the break between Reaches 40 and 41, a storm sewer outfall on the west valley wall has become undermined through channel bed lowering with the headwall and gabion mattress exposed. A scour pool has developed at the base of the valley wall. Additionally, the upstream maintenance hole and a portion of the pipe are exposed on the valley slope. Other storm sewer outfalls within the area of concern are in varying conditions. The most common concern is failure of the revetment on the outflow channel.



Figure 4.2: Failing bank protection and outfall in deteriorated condition in Reach 39 of Morrison Creek An Environmental Assessment should be undertaken for Reaches 39-45 of East Morrison Creek. As part of the EA, a geotechnical investigation, slope stability analysis, and risk assessment should be completed regarding recreational trails and private properties located at the top of the valley. In the interim, the following localized areas outlined in Figure 4.3 and Figure 4.4 should be monitored with emergency works undertaken, as required.



Figure 4.3: Downstream locations for monitoring and possible emergency works on East Morrison Creek



Figure 4.4: Upstream locations for monitoring and possible emergency works on East Morrison Creek



4.3.2 Munn’s Creek, Reaches 33-35 Reaches 33 and 35 of Munn’s Creek were identified as the third- and fourth-ranked localized areas of concern in the 2010 study. During the current study, erosion concerns were also identified in Reach 34. As such, it is recommended that erosion in Munn’s Creek be addressed on a reach-scale. Failure of revetments and bank erosion were found throughout Reaches 33-35 of Munn’s Creek. The results of the RGA showed that Reaches 33 and 35 were “in adjustment” while Reach 34 was classified as “in transition”. The dominant channel process in all reaches was found to be widening while all reaches also exhibited signs of degradation. Exposed Queenston shale was found on channel bed and banks intermittently throughout the reaches. Upstream of Culham Street, down-cutting of the channel has resulted in undermining of gabion basket bank treatment on the right bank. The gabion baskets have slumped into the channel and are impeding conveyance. Further upstream, channel degradation has resulted in failure of the gabion basket grade control at a recreational trail crossing and slumping of the upstream armourstone bank protection. Downstream of McCraney Street West, bank erosion is putting the recreation trail at risk. Throughout the remainder of Reach 34, bank treatments are undermined, slumping, and outflanked due to channel widening and degradation. This includes armourstone and gabion basket revetments providing bank protection at a pedestrian crossing. At the time of the field walk, channel down-cutting had resulted in a perched condition at the culvert for Miller Road at the upstream end of Reach 34. Repairs were undertaken at this culvert in 2015 after the field walks. On the upstream side of the culvert, vegetated stone was placed on the left bank (looking upstream). On the downstream end of the culvert, stone was placed to remediate the perched condition and the failed gabion baskets in the immediate vicinity of the culvert were removed. However, the remainder of the failed gabion bank revetment was left in place and should be addressed through channel restoration works. At the downstream end of Reach 35, right bank erosion is putting rear yards at risk. Further upstream, right bank erosion is moving towards the fence and parking lot for a townhouse complex. At the upstream end of the reach, fences are encroaching on the Town-owned creek corridor and bank protection measures have been constructed that limit floodplain access. Yard waste dumping was noted in the creek corridor throughout the reach and is contributing to large woody debris jams within the watercourse.



Figure 4.5: Failing gabion basket revetments, perched culvert, and bank erosion adjacent to a parking lot on Munn’s Creek An Environmental Assessment should be undertaken for Reaches 33 to 35 of Munn’s Creek. In the interim, the locations identified in Figure 4.6 should be monitored and emergency works undertaken, as required.



Figure 4.6: Locations for monitoring and possible emergency works on Munn’s Creek



4.3.3 Joshua’s Creek, Reaches 67-68 Reaches 67 and 68 of Joshua’s Creek appear to have been straightened. The channel has gabion basket revetments on the banks and is contained within a limited creek corridor. As such, no RGA or RSAT evaluations were completed for these reaches. However, channel degradation is occurring as evidenced by the undermined and slumping gabion baskets. Channel widening was also noted due to the outflanking of the gabion baskets in various locations. The condition of the gabions baskets is poor from downstream of Brookmill Road to Cornwall Road. In addition to the above-noted undermining, outflanking, and slumping of the treatments, failure of the wire mesh and emptying of the stone was also noted. At Brookmill Road, outflanking and overtopping of the gabion baskets has resulted in erosion at the bridge piers. Storm sewer outfall channels throughout the reaches have become perched due to lowering of the channel bed. As well, a concrete encasement for a Region of Halton’s sanitary sewer was observed upstream of Brookmill Road. Further consultation with the Region is required to determine whether or not this encasement was intended to be exposed. Although works in this area are not a high priority, restoration works could be combined with any bridge work at Brookmill Road. With respect to works at Brookmill Road, it should be noted that a mud-pellet nest was also observed under the Brookmill Road bridge during the site visit. The type of nest was not confirmed nor was the nest confirmed to be active. However, the possibility exists that it was a barn swallow nest. Barn swallow (Hirundo rustica) is a Threatened Species under the Endangered Species Act as administered by the Ontario Ministry of Natural Resources and Forestry. During the Environmental Assessment process, further investigation should be completed to determine whether the bridge is actively used by nesting barn swallows. Consultation with MNRF should be undertaken accordingly. Mitigation measures during construction may include undertaking the works outside the active nesting period and using exclusion netting for works in the vicinity to the bridge.

Figure 4.7: Failing gabion basket revetments along Joshua’s Creek including erosion at bridge piers, outflanking of the gabions, and exposure of a concrete sanitary sewer encasement

4.4 Localized Areas of Concern Localized areas of concern were identified where restorations could be undertaken on a selective basis rather than on a reach-scale. The 2010 study identified 7 localized areas of concern:

• McCraney Creek, Reach 32,

• Taplow Creek, Reach 24,



• Munn’s Creek, Reach 35,

• Munn’s Creek, Reach 33

• Fourteen Mile Creek, Reach 12,

• McCraney Creek, Reach 21, and

• Sheldon Creek, Reach 69. The first 2 areas have either been addressed or are currently being addressed through studies by the Town. Under the currently study, the third and fourth areas have been moved to the second priority under reach long areas of concern while the fifth area has been moved to other areas of concern. Localized repairs on the last area were undertaken following the August 2014 storm event and addressed damage upstream of the pedestrian bridge. This leaves McCraney Creek Reach 21 which is the top localized area of concern in the current study. The sections below provide a description of the localized areas of concern while maps and summary sheets are included in Appendix D.

4.4.1 McCraney Creek Reach 21 Channel bed degradation is posing a risk to infrastructure at the Lakeshore Road and Rebecca Street crossings of McCraney Creek in Reach 21. At Lakeshore Road, the west bridge footings are exposed and bank/valley wall erosion is occurring adjacent to the bridge abutments. On the west bank upstream of Lakeshore Road, down-cutting of a storm sewer outfall channel has exposed an unidentified metal conduit. Further upstream on the west bank, a storm sewer outfall has become perched due to channel bed degradation. At Rebecca Street, the closed bottom crossing is perched as is the storm sewer outfall in the bridge wing wall. High flows from an elevated storm sewer outfall on the upstream side of the crossing have created a scour pool. As noted in the 2010 study, the alignment of McCraney Creek at the Lakeshore Road crossing is not ideal. The creek makes a 90° turn to enter the bridge. Realignment should be considered as part of the restoration works.

Figure 4.8: West abutment at Lakeshore Road, exposed metal conduit at storm outfall channel, and perched condition of Rebecca Street crossing

4.4.2 Glen Oak Creek, Reach 32a Two (2) areas of concern are located in this reach. The first is at Speers Road where gabion basket bank protection at the downstream end of the culvert is failing. Inside the culvert, an



exposed shale knick point is present with a concrete cap. Under the bridge upstream of the knick point, an exposed pipe or bridge support was observed. Town infrastructure mapping shows that 2 water mains and 1 sanitary sewer cross the creek at Speers Road. As such, a further investigation of the risk to infrastructure should be undertaken. Any works on the culvert should also address the cantilevered storm sewer outfall on the west bank upstream of the culvert. The second area of concern is located at Pinegrove Road where channel bed lowering is exposing concrete footings and a drop was observed in the channel profile under the crossing. The possibility that the drop is being caused by an exposed infrastructure crossing should be investigated further as Town infrastructure mapping shows that a water main and a sanitary sewer cross the creek at Pinegrove Road. Additionally, gabion basket revetments are in poor condition upstream and downstream of Pinegrove Road. The study undertaken for this reach should include a capacity analysis at Speers Road and Pinegrove Road.

Figure 4.9: Knick point with concrete cap under Speers Road, gabions in disrepair at Pinegrove Road, and drop in channel bed under Pinegrove Road

4.4.3 Fourteen Mile Creek, Reach 5 The creek has been straightened through this reach with gabion baskets lining the banks. Rear yards are located at the top of banks and gabions are often set back from the creek banks. Although the creek is privately owned, it is understood that the Town has easements through this reach. Intermittent failure of the wire mesh and emptying of the stone was observed. One localized area of gabion undermining and slumping was identified which is at imminent risk of collapse. Spot repairs could be undertaken at this location. However, since the gabion baskets are reaching the end of their life throughout the reach, consideration could be given to reach-based restoration. In the event of a reach-based restoration, a concrete ford located mid-reach should also be addressed. It is undermined and is a probable barrier to non-jumping fish species. The possibility of removing the ford should be investigated.



Figure 4.10: Localized gabion basket failure and concrete ford

4.4.4 Glen Oak Creek, Reach 30 There are 2 issues of concern within Reach 30 of Glen Oak Creek. First, right bank erosion has resulted in exposed tree roots and leaning trees within the creek corridor adjacent to private property upstream of the confluence of Glen Oak Creek and McCraney Creek. Falling trees may result in damage to the retaining wall at the fence or to the house. The second issue occurs further upstream where the creek has been lined with gabion basket revetments. The gabion baskets are in poor condition with mesh on the bottom layer rusted out and rip rap emptying into the creek. Rear yards are located behind the retaining wall. Consideration should be given to combining works at this site with works on McCraney Creek, Reach 22.

Figure 4.11: Leaning trees and failing gabion basket revetments on Glen Oak Creek

4.4.5 McCraney Creek, Reach 22 McCraney Creek crosses under Fourth Line in a closed bottom concrete culvert. On the downstream side of this crossing, gabion bed and bank protection are present. However, channel degradation has resulted in an undermined and outflanked condition for these treatments. Failure of the wire mesh has further degraded the gabion condition with rip rap emptying from the baskets. Erosion on the left bank downstream of the gabions has exposed shale bedrock. Yard waste dumping on the east bank has contributed to debris jams which in turn have directed flows towards the banks, resulting in erosion. Consideration should be given to combining works at this site with works on Glen Oak Creek, Reach 30.



Figure 4.12: Failing gabion baskets at Fourth Line culvert

4.4.6 Fourteen Mile Creek, Reach 5a Within Reach 5a of Fourteen Mile Creek, erosion on the west bank at an outside bend is moving towards the fence line for private property. The top of the eroded bank is within about 6 m of the fence at the closest point. Region of Halton sanitary sewer mapping shows that a sanitary sewer is located on the west side of the creek. A detailed investigation of the location of the sanitary sewer and the risk to it should be undertaken to determine whether or not bank restoration works are required.

Figure 4.13: Bank erosion on the west bank

4.4.7 McCraney Creek, Reach 17 There are 3 areas of concern within Reach 17 of McCraney Creek. The first is located at the downstream end of the Pilgrims Way culvert where channel down-cutting and bank erosion has resulted in a perched and undermined condition at the culvert. The second and third areas of concern are located upstream of Pilgrims Way where bank erosion is occurring where the recreational trail is adjacent to the creek. Opportunity may exist to move the recreational trail away from the creek thereby eliminating the need to undertake creek works upstream of Pilgrims Way.



Figure 4.14: Perched culvert for Pilgrims Way and bank erosion adjacent to recreational trail

4.5 Areas of Concern associated with Road Crossings Three (3) sites were identified where erosion concerns were associated with culverts for road crossings. Restoration works on the channel could be completed along with culvert works. The sections below provide a description of the areas of concern associated with road crossings while maps and summary sheets are included in Appendix E.

4.5.1 Falgarwood Creek, Reach 54a Channel down-cutting has resulted in a perched condition for the headwall and apron of the Falgarwood Drive culvert. A corrugated steel pipe (CSP) storm sewer adjacent to the culvert has disconnected at the first joint upstream. Lands downstream of the road right of way are owned by Conservation Halton. It is understood that a design has been prepared to address these issues but that funding has not been secured by Conservation Halton.

Figure 4.15: Perched culvert and disconnected CSP downstream of Falgarwood Drive

4.5.2 Wedgewood Creek, Reach 95 Conditions are poor at 2 road crossings in Reach 95 of Wedgewood Creek. At Amber Crescent, the bed of the CSP culvert is rusted and failing and the stone retaining walls on the upstream end of the culvert are failing. At Duncan Road, the CSP culvert is in fair condition but the gabion basket bank treatments on the upstream end are failing. The study for this reach should include a capacity assessment for both culverts. Replacement of the Amber Crescent culvert is likely needed while bank restoration may be sufficient (depending on the results of the capacity study) at Duncan Road.



Figure 4.16: Amber Crescent culvert with rusted base and Duncan Road culvert with failing gabion basket revetments

4.5.3 Wedgewood Creek, Reach 58 In reach 58 at Drummond Road, rip rap bank protection is failing on the upstream face of the culvert for Wedgewood Creek. The rip rap may be resulting in reduced capacity of the culvert. This might cause a flooding concern.

Figure 4.17: Upstream face of Drummond Road culvert with rip rap reducing capacity

4.6 Areas of Concern Recommended for Monitoring In addition to the priority sites, a number of reaches were identified where erosion concerns should be monitored. The immediate risk to infrastructure or property is relatively low at these sites. However, should conditions deteriorate, this risk may increase. Summary sheets are included in Appendix F providing descriptions and photographs of the erosion concerns. The 2010 study identified 4 reaches for monitoring:

• Fourteen Mile Creek, Reach 3,

• Glen Oak Creek, Reach 97,

• Taplow Creek, Reach 25, and

• Joshua’s Creek, Reaches 67-68. All of these reaches are included in the current list of areas of concern recommended for monitoring with the exception of Joshua’s Creek Reaches 67-68. The continued degradation of the gabion baskets, the possible exposed sanitary sewer crossing, and the opportunity to combine the works with bridge works at Brookmill Road resulted in these reaches being ranked third in the prioritization of the reach long areas of concern.



4.7 Estimated Costs and Implementation Schedule for Creek Rehabilitation As noted in the introduction, the purpose of the study is to develop an implementation plan to prioritize works on Town watercourses and to provide cost estimates for budgetary planning purposes. Costs estimates were prepared for the long reach areas of concern and the localized areas of concern. Construction costs were based on unit costs summarized in Table 4.7. The total costs are presented in Table 4.8 and Table 4.9 respectively. Although individual EAs will be required to develop all possible remediation alternatives, these cost estimates were based on the likely length of restoration works with unit costs based on values from previous undertaken watercourse remediation works. The costs are in 2015 Canadian dollars. Total costs include a 10% allowance for engineering design and approvals for long reach areas of concern, a 15% allowance for engineering design and approvals for localized areas of concern, and a 15% allowance for contingency costs with values rounded to the nearest $10,000. Table 4.7: Unit Construction Costs used for Cost Estimates

Item Unit Construction Cost

Storm sewer outfall replacement $30,000 each Storm sewer outfall repair $10,000 each Bank restoration (1 side of channel) $2,000/m Bank restoration (2 sides of channel) $3,000/m Armourstone walls (2 sides of channel) $4,500/m An implementation plan was also developed for works on Town watercourses and is presented in Table 4.10. Works identified on the implementation plan will be subject to individual Municipal Class Environmental Assessments for Municipal Infrastructure Projects. For reach long areas of concern, it has been assumed that projects will follow a Schedule B EA. For localized areas of concern, the EA schedule has been determined based on the expected type of works. Screening for the presence of Species at Risk and Endangered Species should be undertaken at the time of the individual EAs.



Table 4.8: Restoration Cost Estimates for Reach Long Areas of Concern Pr

iori

ty

Rea

ch(e

s)

Wat

erco

urse

EA S

tudy

Geo

tech

nica

l St

udy

Bed

and

Bank

W

orks

STM

Out

fall

Wor

k

Engi

neer

ing

Des

ign

&

App

rova

ls (1

0%)

Con

tinge

ncy

(15%

)

Tota

l

Restoration Approach

1 39-45 East Morrison Creek

$100,000 $40,000 $2,000,000 $40,000 $200,000 $360,000 $2,740,000

-Geotechnical investigation and slope stability analysis -Risk assessment for trails and properties located at the top of valley -Replacement of approximately 1 km of bank treatments, including bank work at a pedestrian crossing -Repair of 2 storm sewer outfalls

2 33-35 Munn's Creek $80,000 $30,000 $1,000,000 $0 $100,000 $180,000 $1,390,000

-Geotechnical investigation and slope stability analysis -Investigation of realignment opportunities -Replacement of approximately 500 m of bank treatments

3 67-68 Joshua's Creek $50,000 $20,000 $2,400,000 $0 $240,000 $410,000 $3,120,000

-Geotechnical investigation -Replacement of approximately 800 m of bank treatments (both sides of channel) -Grade control at sanitary sewer crossing



Table 4.9: Restoration Cost Estimates for Localized Areas of Concern Pr

iori

ty

Rea

ch

Wat

erco

urse

EA

Stu

dy

(Sch

edul

e)

Geo

tech

nica

l St

udy

Bed

and

Bank

W

orks

STM

Out

fall

Wor

k

Misc

ella

neou

s

Engi

neer

ing

Des

ign

&

App

rova

ls (1

5%)

Con

tinge

ncy

(15%

)

Tota

l


1 21 McCraney Creek

$80,000 (B) $10,000 $200,000 $40,000 $0 $40,000 $50,000 $420,000

-Geotechnical investigation -Identification of exposed pipe -Approximately 100 m of channel bed and bank restoration with realignment of channel upstream of Lakeshore Road

2 32a Glen Oak Creek

$50,000 (A+) $10,000 $440,000 $10,000 $0 $70,000 $90,000 $670,000

-Capacity analysis for Speers Road and Pinegrove Road culverts -Risk assessment for buried infrastructure -Approximately 40 of channel bed and bank works at Speers Road -Approximately 80 m of gabion basket replacement and bed works at Pinegrove Road

3 5 Fourteen Mile Creek

$30,000 (A+) $10,000 $30,000 $0 $0 $10,000 $10,000 $90,000

-Geotechnical investigation for property on Valley Drive -Localized replacement of failed gabions (approximately 10 m) -Alternative investigation for restoration within the remainder of the reach including consideration of removal of concrete ford

4 30

22

Glen Oak Creek McCraney Creek

$80,000 (B) $20,000 $550,000 $30,000 $0 $90,000 $110,000 $880,000

-Geotechnical investigation -Replacement of 160 m of gabions with armourstone walls -Realign/protect 40 m of eroded bank where trees are undermined -Bank and bed restoration works, likely armourstone walls with grade control (approximately 25 m)



Prio

rity

Rea

ch

Wat

erco

urse

EA

Stu

dy

(Sch

edul

e)

Geo

tech

nica

l St

udy

Bed

and

Bank

W

orks

STM

Out

fall

Wor

k

Misc

ella

neou

s

Engi

neer

ing

Des

ign

&

App

rova

ls (1

5%)

Con

tinge

ncy

(15%

)

Tota

l


5 5a Fourteen Mile Creek

$60,000 (B) $0 $100,000 $0 $0 $20,000 $20,00 $210,000

-Investigate risk to sanitary sewer -If protection is needed, investigate options for bank revetments (including bioengineering, as appropriate) and/or channel realignment

6 17 McCraney Creek

$20,000 (A+) $0 $90,000 $0 $10,000 $20,000 $20,000 $160,000

-Grade control and localized bank restoration at perched culvert -Investigate options for bioengineering -Move recreational trail away from eroding banks



Table 4.10: Recommended Implementation Schedule for Restoration Projects, 2016-2020

Year Projects Estimated Costs (2015$)

2016 East Morrison Creek, Reaches 39-45 – EA Taplow Creek, Reaches 24-25 – EA, design, and permitting West Morrison Creek, Reaches 36-38 – on-going EA

$140,000 $70,000

Funding 2013 Total 2016 $210,000

2017

East Morrison Creek, Reaches 39-45 – design & permitting McCraney Creek, Reach 21 – EA, design, & permitting Taplow Creek, Reaches 24-25 – construction West Morrison Creek, Reaches 36-38 – construction

$200,000 $130,000 $700,000

$1,000,000 Total 2017 $2,030,000

2018 East Morrison Creek, Reach 39-45 – construction McCraney Creek, Reach 21 – construction Glen Oak Creek Reach 32a – EA, design, & permitting

$2,400,000 $290,000 $130,000

Total 2018 $2,820,000

2019

Munn's Creek, Reaches 33-35 – EA Glen Oak Creek, Reach 32a – construction Fourteen Mile Creek, Reach 5 – design, permitting & construction

$110,000 $540,000 $90,000

Total 2019 $740,000

2020 Munn's Creek, Reaches 33-35 – design & permitting Glen Oak & McCraney Creeks, Reaches 30 & 22 – EA

$100,000 $100,000

Total 2020 $200,000

2021+

Munn’s Creek, Reaches 33-35 – construction Glen Oak & McCraney Creeks, Reaches 30 & 22 – design, permitting, & construction Joshua's Creek, Reaches 67-68 – EA, design, permitting, & construction Fourteen Mile Creek, Reach 5a – EA, design, permitting, & construction McCraney Creek, Reach 17 – EA, design, permitting, & construction

$1,180,000 $780,000

$3,120,000

$210,000

$160,000

Total 2021+ $5,450,000

4.8 Outfalls, Pedestrian Crossings, and Debris Jams During the field assessment, storm sewer outfalls, pedestrian crossings, and debris jams were identified and ranked. Maintenance requirements are outlined in the sections below.

4.8.1 Storm Sewer Outfalls The condition of storm sewer outfalls was assessed in the field and those requiring maintenance were identified. The following categories were established for maintenance:

• Priority for Maintenance – Restoration of these outfalls should be prioritized.



• Maintenance – Restoration works are required on these outfalls once the priority outfalls have been addressed.

• Maintenance as part of Erosion Works – These sites are located at erosion sites and will be addressed as part of the respective erosion studies.

• Minor Maintenance – These sites typically have debris accumulations which should be removed to ensure conveyance.

• Monitoring – These outfalls have some minor deficiencies but do not require immediate repair.

The storm sewer outfalls which require maintenance or monitoring are presented in Figure 4.19. Additional information for the sites identified as “Priority for Maintenance” or “Maintenance” is presented on summary sheets in Appendix G, as is a summary of the minor maintenance requirements. Within the monitoring category, it should be noted that the storm sewer outfall in Reach 56 on Wedgewood Creek is affected by a privately installed armourstone wall behind 239 Cardinal Drive (Figure 4.18). The armourstone wall is located upstream of the Town storm sewer easement. The wall is slumping and stones are leaning onto the storm sewer outfall pipe. The corner of the stone for the wall is poised to fall onto the storm sewer outfall. The last section of the pipe is disconnected and is slumping. This outfall is in close proximity to the erosion site in Reach 56 within the monitoring category. Should works be undertaken on the outfall, channel restoration works should be considered at the same time.

Figure 4.18: Armourstone wall at storm sewer

4.8.2 Pedestrian Crossings The condition of pedestrian crossings was assessed during the field walks. Those bridges with deficiencies were noted and categorized as follows:

• Maintenance – creek erosion or degradation of material conditions have resulted in the need for works on or at the pedestrian bridge.

• Monitoring – minor deficiencies were noted and should be monitored to identify future need for maintenance.

The locations of the pedestrian crossings requiring maintenance or monitoring are show on Figure 4.20. Additional information for each site is presented on summary sheets in Appendix H.



4.8.3 Debris Jams While completing the field walks, the locations of debris jams were noted and the risk posed by the jams was evaluated. The following categories were used to rank the debris jams:

• Low – the debris jams are small in size or are located in a valley without any buildings located nearby.

• Medium – the debris jams are located in areas closer to buildings but do not pose an imminent risk of backwater and flooding

• High – the debris jams are significant in size or are located in areas where backwater conditions may put buildings or private property at risk.

The locations of debris jams ranked as “medium” and “high” are show on Figure 4.21. It is recommended that the priority debris jams be removed as part of the Town’s regular maintenance program.



Figure 4.19: Priority Storm Sewer Outfalls



Figure 4.20: Priority Pedestrian Crossings



Figure 4.21: Priority Debris Jams



5 RECOMMENDATIONS The 2015 creek inventory and assessment study covered the minor 12 watercourses within the Town of Oakville, omitting the major watercourses of Sixteen Mile Creek and Bronte Creek, and areas of new development north of Dundas Street. The extent of the watercourses assessed was the same as in the previous studies with the exception of watercourses which were no longer present due to development and West Morrison Creek Reaches 36-38 for which an EA and detailed design is underway. Additionally, some reaches located on private property with no easements were also omitted. It is recommended that the Town undertake an update to the creek inventory and assessment study in 2020. During this study, it is recommended that, in addition to the Town-owned reaches covered in the previous studies, any Town-owned remnant channels be assessed. This would include the following channels:

• Sheldon Creek tributary west of Great Lakes Boulevard; • Fourteen Mile Creek tributary west of Valley Ridge Drive; • McCraney Creek and tributary between the railway corridor and the QEW; • McCraney Creek tributary east of Fieldcrest Lane; • Taplow Creek between Fourth Line and the South Service Road; • Taplow Creek upstream of Upper Middle Road; • Glen Oak Creek upstream of Upper Middle Road; • West Morrison Creek tributary between Sheridan College and River Oaks Boulevard

East; • East Morrison Creek tributary downstream of Kathleen Crescent; • East Morrison Creek between Postridge Drive and Dundas Street East; and • Wedgewood Creek between Upper Middle Road and Valleybrook Drive.

The locations of these reaches are shown in Figure 5.1. Some of these reaches are fenced off and thus, access will need to be coordinated with Town staff. Following inspection, the 2020 report should make recommendations as to the frequency of inspection of these additional reaches. Between 2016 and 2020, it is recommended that the Town undertaken yearly monitoring of the sites identified in the lists of reach long areas of concern, localized areas of concern, and areas of concern associated with road crossings (Table 4.3, Table 4.4, and Table 4.5 respectively). Timing of the inspections is recommended to be in the spring, after the freshet and prior to the leaf-out period. Additionally, inspections of these sites and those identified in the monitoring category (Table 4.6) should be undertaken following high-magnitude, low-frequency storm events.



Figure 5.1: Locations of reaches to be included in 2020 assessment



6 REFERENCES AECOM (2011) 2010 Creek Erosion Inventory and Assessment Study, Town of Oakville, May 2011. Conservation Halton and Environmental Water Resources Group Ltd. (2015) August 4th, 2014 Storm Event, Burlington, April 2015. Galli, J. (1996) Rapid Stream Assessment Technique, field methods, Metropolitan Washington Council of Governments, 36pp. Halton Region (2015) Yard Waste, http://halton.ca/cms/one.aspx?portalId=8310&pageId=12241, retrieved October 20, 2015. Heaton, M.G., Grillmayer, R., and Imhof, J.G. (2002) Ontario’s Stream Rehabilitation Manual, Ontario Streams, Belfountain, ON. Maryland Department of the Environment Water Management Administration (2000) Maryland’s Waterway Construction Guidelines (revised). Ontario Ministry of the Environment (2003) Stormwater Management Planning and Design Manual.

http://halton.ca/cms/one.aspx?portalId=8310&pageId=12241


Aquafor Beech Limited Ref: 65759

Appendix A: Geomorphic Summary of Reaches



Appendix B: Sample Data Collection Forms



Appendix C: Details for Reach Long Areas of Concern



Appendix D: Details for Localized Areas of Concern



Appendix E: Details for Areas of Concern associated with Road Crossings



Appendix F: Details for Areas of Concern Recommended for Monitoring



Appendix G: Summary Sheets for Priority Storm Sewer Outfalls



Appendix H: Summary Sheets for Priority Pedestrian Crossings

Documents

Creek Inventory and Assessment Study Final Report planning/ErosionStudy-2015.pdf · Creek Inventory and Assessment Study Final Report A report submitted by: Aquafor Beech Ltd. June