Etobicoke and Mimico Creeks Watersheds Technical Update Report
AQUATIC SYSTEM - INSTREAM BARRIERS TO FISH PASSAGE
TABLE OF CONTENTS
9.0 AQUATIC SYSTEM - INSTREAM BARRIERS TO FISH PASSAGE ...... 9-1 9.1 Watershed Objectives, Indicators and Targets ...... 9-1 9.2 Objectives of Technical Update ...... 9-2 9.3 Data Sources, Field Surveys and Methods ...... 9-3 9.3.1 Desktop Assessment ...... 9-3 9.3.2 Field Surveys ...... 9-5 9.3.3 Data Synthesis and Analyses ...... 9-6 9.4 Existing Conditions and Interpretation ...... 9-7 9.4.1 Fish Species in Etobicoke and Mimico Creeks ...... 9-8 9.4.2 On-Line Stormwater Management Ponds in the Etobicoke and Mimico Creeks Watersheds ...... 9-9 9.4.3 Channelization of Etobicoke and Mimico Creeks ...... 9-10 9.4.4 Impervious Cover in Etobicoke and Mimico Creeks Watersheds...... 9-13 9.4.5 Overview of Barriers within Etobicoke Creek Watershed ...... 9-16 9.4.6 Overview of Barriers within Mimico Creek Watershed ...... 9-30 9.4.7 Overall Summary of Existing Conditions ...... 9-38 9.5 Decision Criteria for Selecting Prioritiy Barriers For Management ...... 9-38 9.5.1 Fish IBI Scores and Natural Stream Habitat Areas ...... 9-39 9.5.2 Rehabilitation Projects ...... 9-41 9.5.3 Riparian Vegetation Cover ...... 9-43 9.5.4 Small Scale Barriers ...... 9-43 9.6 Management Recommendations –Etobicoke Creek Priority Barriers ...... 9-45 9.6.1 Category A - Lake to Headwaters ...... 9-45 9.6.2 Category B – Extending Existing Natural Habitat ...... 9-49 9.6.3 Category C – Stewardship ...... 9-51 9.7 Management Recommendations - Mimico Creek Priority Barriers ...... 9-54 9.7.1 Category A – Lake to Headwaters ...... 9-54 9.7.2 Category B – Extending Existing Natural Habitat ...... 9-58 9.7.3 Category C – Stewardship ...... 9-61 9.8 Overall Summary of Management Considerations for Etobicoke and Mimico Creeks Watersheds ...... 9-63 9.9 References ...... 9-64 9.10 Appendix 9-A – Assessment Form for Barrier Survey ...... 9-66
Toronto Region Conservation, Final Draft October 2010 Etobicoke and Mimico Creeks Watersheds Technical Update Report
LIST OF FIGURES
Figure 9-1: Fish Sampling Locations in Etobicoke and Mimico Creeks Watersheds ...... 9-4 Figure 9-2: Sheet Flow Conditions Preventing Fish Passage South-West of Clark Boulevard and West Drive...... 9-7 Figure 9-3: Graphic Depicting Fish Passage Calculation...... 9-7 Figure 9-4: Location of On-line Stormwater Management Ponds in Etobicoke and Mimico Creeks Watersheds ...... 9-11 Figure 9-5: Channelized Streambed of Etobicoke and Mimico Creeks Watersheds ...... 9-12 Figure 9-6: Percent Impervious Cover in Etobicoke and Mimico Creeks Watersheds, 2008 . 9-14 Figure 9-7: Natural Flow in Etobicoke West Branch Subwatershed ...... 9-15 Figure 9-8: Impacted Flow in Lower Etobicoke Subwatershed ...... 9-15 Figure 9-9: Impacted Flow in Mimico Creek Watershed ...... 9-15 Figure 9-10: Existing Instream Structures - Etobicoke Creek Watershed ...... 9-17 Figure 9-11: Lower Etobicoke Existing Instream Structures, including: Etobicoke Main Branch, Tributary 4, and Little Etobicoke ...... 9-19 Figure 9-12: Weir at CN Railway Line ...... 9-21 Figure 9-13: Spring Creek Existing Instream Structures within Spring Creek Subwatershed 9-23 Figure 9-14: Erosion North-East of Drew Road and Bramalea Road ...... 9-24 Figure 9-15: Chinguacousy Park Dam North-West of Queen Street and Central Park Road . 9-24 Figure 9-16: Channel Erosion at Avondale Tributary at Dixie and Clarke ...... 9-25 Figure 9-17: Upper Etobicoke Existing Instream Structures including: Tributary 3, Etobicoke West Branch and Etobicoke Headwaters Subwatersheds ...... 9-27 Figure 9-18: Flow Dissipating Weir in Tributary 3 South-West of Midway Boulevard and Dixie Road ...... 9-28 Figure 9-19: Weir Structure in West Tributary located North-West of Courtney Park Drive and Tomken Road in 2006(a) low flow and 2008 (b) high flow...... 9-28 Figure 9-20: Step Weir at Drew Road East of Dixie Road...... 9-29 Figure 9-21: Perched Culvert North of 407 West of Dixie Road...... 9-29 Figure 9-22: Existing Instream Structures in Mimico Creek Watershed ...... 9-31 Figure 9-23: Existing Instream Structures in Mimico Creek Main Branch ...... 9-33 Figure 9-24: Existing Instream Structures in Mimico Creek East Branch ...... 9-35 Figure 9-25: Damaged Infrastructure south-west of Clark Blvd. and Walker Dr. (MCE 103) .. 9-36 Figure 9-26: Existing Instream Structures in Mimico Creek West Branch ...... 9-37 Figure 9-27: Index of Biotic Integrity - Etobicoke and Mimico Creeks Watersheds ...... 9-40 Figure 9-28: Rehabilitation Projects – Etobicoke and Mimico Creeks Watersheds (2009) .... 9-42 Figure 9-29: Riparian Cover for Etobicoke and Mimico Creeks Watersheds ...... 9-44 Figure 9-30: Priority Category A – Lake to Headwaters- Etobicoke Creek Watershed * ...... 9-46 Figure 9-31: Weir at Toronto Golf Club Bridge (ECLOW006) ...... 9-48 Figure 9-32: Weir 500m South of Q.E.W. (ECLOW011) ...... 9-48 Figure 9-33: Weir at Bloor Street West of Dixie Mill Road (ECLOW029) ...... 9-48 Figure 9-34: Weir at Britannia Road and East Road (ECLOW039) ...... 9-48 Figure 9-35: Weir South of Queen Street West of Centre Street (MEE023) ...... 9-49 Figure 9-36: Natural Barriers Weybridge Park (MEE033), Near Valleywood Development (MEE059), North of Mayfield between Hurontario and Kennedy (MEE060) ...... 9-49 Figure 9-37: Priority Category B – Extending Existing Natural Habitat- Etobicoke Creek Watershed * ...... 9-50 Figure 9-38: Priority Category C – Stewardship Projects – Etobicoke Creek Watershed ...... 9-52
Toronto Region Conservation, Final Draft October 2010 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Figure 9-39: Rock obstruction north-east of East Gate Parkway and Tomken Road (ECLE031) ...... 9-53 Figure 9-40: Old sediment fence north-east of Bovaird Road and 410. (SPHL009) ...... 9-53 Figure 9-41: Priority Category A – Lake to Headwaters – Mimico Creek Watershed ...... 9-55 Figure 9-42: Weir at Q.E.W. (MC005) ...... 9-56 Figure 9-43: Weir at Q.E.W. (MC007) ...... 9-56 Figure 9-44: Weir 500m south of Berry Road (MC011) ...... 9-57 Figure 9-45: Weir 100 m north of Berry Road (MC013) ...... 9-57 Figure 9-46: Weir 10m south of Meadowcrest Road (MC016) ...... 9-57 Figure 9-47: Weir 10m north of Meadowcrest Road (MC017) ...... 9-57 Figure 9-48: Weir 80m south of Meadowvale Drive(MC020) ...... 9-57 Figure 9-49: Weir 90m south of Meadowvale Drive (MC021) ...... 9-57 Figure 9-50: Weir 240m north of Meadowvale Drive (MC024) WSC ...... 9-58 Figure 9-51: Weir 70m downstream of Dundas Street (MC029) ...... 9-58 Figure 9-52: Weir 260m north-west of Skyway Ave and Highway 27 (MC055) ...... 9-58 Figure 9-53: Ramp at upstream end of Zahavy Way Rd Crossing (MC083) ...... 9-58 Figure 9-54: Priority Category B – Extending Existing Natural Habitats – Mimico Creek Watershed ...... 9-59 Figure 9-55: Railway Crossing 300m north-east of Goreway Drive and Brandon Gate Drive (MCE011) ...... 9-60 Figure 9-56: Weir 100m south of Intermodal Drive (MCE050) ...... 9-60 Figure 9-57: Weir 250m north-west Highway 407 and Goreway Drive (MCE049) ...... 9-60 Figure 9-58: Priority 1 Area (MCW042) ...... 9-61 Figure 9-59: Priority Category C – Stewardship Projects – Mimico Creek Watershed ...... 9-62
LIST OF TABLES
Table 9-1: Watershed Objectives, Indicators and Targets ...... 9-2 Table 9-2: Summary of Etobicoke Creek Instream Barrier Assessment (2005-2008) ...... 9-16 Table 9-3: Lower Etobicoke and Etobicoke Main Branch Subwatersheds, Instream Barrier Assessment (2005) ...... 9-20 Table 9-4: Tributary 4 Subwatershed, Instream Barrier Assessment (2005) ...... 9-20 Table 9-5: Little Etobicoke Subwatershed, Instream Barrier Assessment (2005) ...... 9-21 Table 9-6: Total Spring Creek Subwatershed, Instream Barrier Assessment (2008) ...... 9-22 Table 9-7: Main Branch of Spring Creek Subwatershed, Instream Barrier Assessment (2008) . 9- 24 Table 9-8: Bramalea Tributaries within Spring Creek Subwatershed, Instream Barrier Assessment (2008) ...... 9-25 Table 9-9: Tributary 3 Subwatershed, Instream Barrier Assessment (2008) ...... 9-26 Table 9-10: Etobicoke West Branch, Instream Barrier Assessment (2008) ...... 9-29 Table 9-11: Summary of Etobicoke Creek Headwaters Instream Barrier Assessment (2008) 9-30 Table 9-12: Summary of Mimico Creek Instream Barrier Assessment (2009) ...... 9-30 Table 9-13: Mimico Creek Main Branch, Instream Barrier Assessment (2009) ...... 9-32 Table 9-14: Mimico Creek East Branch, Instream Barrier Assessment (2009) ...... 9-34 Table 9-15: Mimico Creek West Branch, Instream Barrier Assessment (2009) ...... 9-36 Table 9-16: Decision Criteria for Selecting Priority Barriers for Management ...... 9-39 Table 9-17: Etobicoke Creek Priority Barriers for Management Category A ...... 9-45
Toronto Region Conservation, Final Draft October 2010 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Table 9-18: Etobicoke Creek Priority Barriers for Management Category B ...... 9-49 Table 9-19: Management Considerations for Priority Category C – Stewardship Opportunities 9- 51 Table 9-20: Mimico Creek Priority Barriers for Management Category A ...... 9-54 Table 9-21: Mimico Creek Priority Barriers for Management Category B ...... 9-58 Table 9-22: Mimico Creek Priority Barriers for Management Category C ...... 9-61
Toronto Region Conservation, Final Draft October 2010 Etobicoke and Mimico Creeks Watersheds Technical Update Report
9.0 AQUATIC SYSTEM - INSTREAM BARRIERS TO FISH PASSAGE
The continuum of a river system from the small headwater tributaries to the mouth produces a diversity of habitat types that support a range of fish communities from pollution sensitive specialists to tolerant generalists. In a natural system these biota are spatially found according to a variety of factors, including habitat suitability, predation, food supply and swimable access to a given reach.
There are many examples in nature where streams can become fragmented and fish passage is temporally prevented as a result of beaver dams, log jams and seasonally low water levels. In urban systems, the issue of habitat fragmentation is exacerbated by the construction of in- stream structures that alter the flow regime and/or physically block fish passage due to the height differential from the stream bed. In these cases, the structure is termed an instream barrier. Anthropogenic barriers include: dams, weirs,, ramps, damaged infrastructure, culverts and other pedestrian, road or railway crossing infrastructure. Over the years, many instream structures have been constructed in the Etobicoke and Mimico Creeks. The number of these structures, and resultant barriers, has increased over time.
When fish passage is prevented, aspects of survival including spawning, foraging, and escape from predators is compromised (Gosset et al., 2006). Habitat fragmentation can cause fish populations to have increased susceptibility to bacterial, viral and parasitic infections as a consequence of poor genetic diversity (Hanfling et al., 2004). Increased fragmentation in an urban system heightens the impacts of large storm events or chemical spills. Storm events can wash fish downstream of a barrier with limited ability to return to appropriate habitat (Allendorf et al., 1987). Fish may not be able to escape a chemical spill if upstream movement is the only means of finding refuge resulting in mass fish kills (Allendorf et al., 1987; Wofford et al., 2005; Walsh et al., 2005).
The GTAA Living City Project Etobicoke Creek, The Aquatic System (TRCA, 2006) and later the report Turning over a new leaf: The Etobicoke and Mimico Creeks Watersheds Report Card 2006 (TRCA, 2006), recommended an instream barrier assessment for these creeks. From a fisheries management perspective, the outcome of such an assessment is to identify all the barriers and determine the priority sequence for removal or mitigation that will improve the health of the fishery through increased connectivity and stream health. As such, recommendations in this report are based on ecological benefit only would still be subject to approvals and/or permits required under any existing laws and regulations, for example, Lakes and Rivers Improvement Act (LRIA), Federal Fisheries Act (FFA), and Conservation Authority Act (CAA). Further, structure owner authorization, cost estimates and technical feasibility have not been evaluated in this document.
9.1 WATERSHED OBJECTIVES, INDICATORS AND TARGETS This aquatic technical component illustrates the findings of the barrier assessment work and identification of priority barriers for management action. The discussion is guided by the relevant objectives, indicators and targets for the aquatic system, as defined in the previous watershed report card, and recommends new targets (see Table 9-1). A full assessment of current aquatic system condition was not deemed necessary at this time, because there have not been significant changes at the watershed scale to suggest existing aquatic data set
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requires updating; formal barrier inventory and prioritization were identified as a data gap in the 2006 report card.
Table 9-1: Watershed Objectives, Indicators and Targets Aquatic System Objective: Aquatic ecosystems are diverse, balanced and self-sustaining
Indicator Targets
Fish • By 2025, the IBI rating at three sites in Etobicoke Creek should be improved to “fair” Communities from “poor” – Not addressed in this Technical Update. • By 2025, there will be no further degradation of the aquatic community – Not addressed in this Technical Update. • By 2025, fish will be found at all sites sampled in Mimico Creek – Not addressed in this Technical Update.
Benthic • By 2012, all benthic invertebrate sampling stations should have an invertebrate Invertebrate community that is rated as fair or better – Not addressed in this Technical Update. Communities • By 2025, at least 40% of benthic invertebrate stations should have an invertebrate community that is rated as good – Not addressed in this Technical Update.
Riparian Zone • By 2025, 75% of the riparian zone should contain natural cover. • By 2025 75% of the riparian zone should be made up of forest cover.
Fish Passage • By 2025 have 50% of priority barriers identified in Category A and Category B mitigated for fish passage; and 100 % of Category C barriers removed in Etobicoke and Mimico Creeks (TRCA, 2010) 1 • By 2025 identify strategic barriers to remain throughout the watershed.
Invasive and Actively manage for no further introduction of any invasive or exotic species 2 Exotic Species
9.2 OBJECTIVES OF TECHNICAL UPDATE As recommended by the GTAA Living City Project Etobicoke Creek, The Aquatic System (TRCA, 2006) and Turning over a new leaf: The Etobicoke and Mimico Creeks Watersheds Report Card 2006, an instream barrier assessment was necessary to identify instream barriers for management which will improve fish passage and habitat. This Technical Update was designed to address this need.
The principle objectives of the Etobicoke and Mimico Creeks barrier assessment work are:
Determine the total number of instream structures and identify those that are barriers to fish passage for:
1 New Fish Passage target developed as part of the Technical Update (TRCA, 2010) to fill a gap in the previous management framework for these watersheds. 2 New Invasive and Exotic Species target developed as part of the Technical Update (TRCA, 2010) to fill a gap in the previous management framework for these watersheds.
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• All species; • Non-jumping fish species; and • Invasive fish species.
Provide key direction for instream barrier management to assist watershed management decisions regarding: • Enhancement and rehabilitation of fish habitat (e.g. improved connectivity) and fish health of native fish populations; • Restriction of invasive species passage; and • Identification of stewardship opportunities.
9.3 DATA SOURCES, FIELD SURVEYS AND METHODS The instream barrier assessment included three components:
• desktop assessment to identify potential structures and fish species presence; • field surveys to confirm presence and type of structure; and • data synthesis and analysis to examine and quantify passage issues.
9.3.1 Desktop Assessment Prior to the initiation of this Technical Update, barrier inventory and assessment work began early in 2003 to fill a data gap in anticipation of formal management plans being developed. At that time, 1999 ortho photos were used to generate GIS mapping of potential barriers within Etobicoke and Mimico Creeks. Results were mapped and later cross-referenced with field data. Maps were revised to reflect field information.
The characterization of fish community, overtime, in Etobicoke and Mimico Creeks was determined using two sources of data: fish collection records provided by the Ministry of Natural Resources (1927 to 1998) and TRCA’s Regional Watershed Monitoring Program (RWMP). RWMP fish collection records from the years 2002, 2005 and 2007 for Mimico Creek and 2001, 2004 and 2008 for Etobicoke Creek were used (see Figure 9-1).
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Figure 9-1: Fish Sampling Locations in Etobicoke and Mimico Creeks Watersheds
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9.3.2 Field Surveys Following the ortho photo interpretation, TRCA staff walked a portion of the Etobicoke Creek in 2005, conducting a survey of each instream structure. The survey was completed in 2008. The Mimico Creek was walked in its entirety during 2009. All field surveys were conducted during summer low flow conditions, to the extent possible, and where land owner permission was granted. A barrier assessment form was completed at each structure observed (see Appendix 9-A). Instream structures were defined as structures that came in contact with the stream flow and/or spanned a watercourse. The various types of instream structures are defined below:
Dam: Under the Lakes and Rivers Improvement Act (2007) a dam is defined as any structure created to hold back water to raise water levels, create a reservoir to control flooding, or divert water. The structure typically creates a vertical drop on the downstream side and has stop logs or control valves to alter water level. Water release can occur through top draw or bottom draw mechanisms.
Top draw – the water is released over the top of the structure Bottom draw – the water is released out the bottom of the structure
Weir: A small dam structure that creates a vertical drop on the downstream side and may impound water but does not alter the level of the upstream impoundment with stop logs or control valves. A general term is a drop structure.
Ramp: A structure that consists of a hard sloping feature to facilitate transport of heavy objects in and out of the watercourse (e.g. boats) or maybe used as a ford.
Channelization: Extended slabs of concrete used to line the bottom and often banks of the stream to more quickly convey water during storm events (reduces risk of flooding) and/or stabilize the watercourse.
Damaged Infrastructure: Various instream works, used to stabilize or channelize streams which have, over time, fallen to disrepair causing alteration to flow (e.g., broken gabion baskets, cracked/shifted concrete slabs).
Natural Barrier: A structure that is not specifically designed and/or constructed by people, such as beaver dams, log or debris jams or when the stream bed has eroded down creating a vertical drop, or waterfall; natural change in stream bed grade.
Crossings:
• Road Crossing: A structure that allows the passage of vehicular and/or pedestrian traffic over a watercourse; most often supported by use of a culvert or bridge.
• Pedestrian Crossing: A structure that allows the passage of pedestrians (only) over a watercourse; most often supported by use if a culvert or bridge.
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• Railway Crossing: A structure that allows the passage of railroad traffic over a watercourse; most often supported by use of a bridge that has re-enforcing infrastructure within the stream.
Buried Streams: A condition where a watercourse ends in a pipe or no longer exists at surface; this was not considered a barrier as fish habitat was not fragmented, rather it has been lost.
The information collected, and field measurements taken were: • type of structure • presence or absence of groundwater • materials of structure • discharge evidence (e.g. iron staining, watercress) • stream width • upstream and downstream sketch • bank condition • photos of the structure • channel condition • UTM coordinates using a handheld Global Positioning System (GPS) unit
If an instream structure caused a change in stream elevation (e.g. drop structure) or produced low water level conditions un-navigable by fish species (e.g. sheet flow), additional measurements were collected to calculate the potential effect on passage. The additional measurements taken were as follows:
• depth of pool (the deepest portion of water downstream of the structure but within 1 metre (perpendicular) to the barrier) • height from the lip of the structure to the stream bed below • height from the lip of the structure to the surface of the water • temperature of stream above and below structure • digital photographs of structure
9.3.3 Data Synthesis and Analyses Field data were entered into a Microsoft Excel spreadsheet. Photographs were coded and electronically linked to appropriate structures. The spreadsheet was then converted to an Arcview shapefile using the Universal Transverse Mercator (UTM) coordinates. GPS locations of the structures were corrected to correspond with the geo-referenced aerial photography where necessary.
Instream structures that did not alter the flow of the watercourse were considered passable for fish species and not classified as barriers. All the remaining structures were then assessed as either causing sheet flow or not.
Sheet Flow an Issue Sheet flow is a condition when flow is conveyed as a thin layer of water too shallow for fish to swim upstream. If sheet flow was observed over\ through a structure and any downstream pool depth was less than 5 cm, the structure was determined to be a barrier to all fish species passage. Photographs of the structures were also used to confirm these conditions (see examples in Figure 9-2).
Sheet Flow not an Issue
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In the case when sheet flow was NOT an issue, three types of assessments were made resulting in three categories:
1) not a barrier 2) barrier to non-jumping fish species only 3) barrier to all species
If flow was continual, not sheeting over\ through the structure, and the stream elevation change was less than 5 cm, it was determined that all fish species could pass. If the above flow conditions were present, but there was an elevation change of 5cm to 8 cm from stream level to bottom of structure, this was considered not-passable for non-jumping species only.
Structures creating an elevation change of greater than 8 cm were considered not passable for non-jumping species and possibly jumping species. For this assessment, passage for jumping fish species was determined by calculating the “height of structure to top of water” divided by the measured “pool depth”. Ratios equal to or less than 1, were considered passable by jumping species. Figure 9-3 details the calculations that are based on brook trout (Salvelinus fontinalis) studies which compared the jumping ability of the species using plunge pool depth, height of waterfall and length of fish (Stuart, 1962). Other salmonids are considered superior jumping species in comparison to brook trout. Therefore the application of a 1:1 passage for salmonids in Etobicoke and Mimico Creeks is considered conservative.
Figure 9-2: Sheet Flow Conditions Figure 9-3: Graphic Depicting Fish Passage Preventing Fish Passage South-West of Calculation. Clark Boulevard and West Drive.
9.4 EXISTING CONDITIONS AND INTERPRETATION The following section provides a summary of the factors that drive the health of an urban aquatic system, whether they are influences on stream form (e.g., channelization and barriers) or function (e.g., stormwater and impervious cover). The fish community is also described for both watersheds as the indicator of the cumulative effects of these abiotic factors and helps showcase where there are opportunities to improve both the overall health and targeted portions of the watersheds.
Toronto Region Conservation, 2010 9-7 Etobicoke and Mimico Creeks Watersheds Technical Update Report
9.4.1 Fish Species in Etobicoke and Mimico Creeks The dominant fish community through the Etobicoke Creek watershed is comprised of cool- warm water, tolerant species that can occupy many different types of habitat (i.e., they are generalists). Both fish abundance and diversity are low in the Etobicoke Creek relative to less urban systems within the Greater Toronto Area. Diversity does improve in the headwaters where a few habitat specialists and coldwater species still persist. However, the greatest biodiversity is measured in and around the mouth of the river where lake-based species are also collected.
Below the first barrier in Etobicoke Creek (downstream of Lakeshore Blvd.), jumping salmonid species, such as migratory rainbow trout (Oncorhynchus mykiss) and chinook salmon (Oncorhynchus tshawytscha) have been observed in low numbers. The fish collection records indicate that these lake-based salmonids are not further up in the watershed; however, anecdotal observations of chinook salmon in the lower reaches (above the first barrier) have been received. The routine monitoring conducted by TRCA does not sample during the spawning run of these two species (mid-April to May for rainbow trout and late-September for chinook) and thus the most likely times for positive collection is not sampled.
Rainbow trout and Chinook salmon are stocked in neighbouring watersheds and it is from this practice that these species are present in Etobicoke Creek. These species are not expected to remain in the tributaries, as adults, for very long. Rainbow trout are also stocked in Heart Lake, high up in the Etobicoke Creek Watershed.
Native, migratory, non-jumping species include white sucker (Catostomus commersoni) and common shiner (Notropis cornutus). Migratory white sucker and common shiner (spawn late May – mid June) have been collected throughout the lower watershed suggesting, during seasonal high water, passage over the first barrier is possible, but fish passage is an issue under low flow conditions.
Other , non-jumping lake-based species, found near the mouth include alewife (Alosa pseudoharengus), brown bullhead (Ictalurus nebulosus), emerald shiner (Notropis atherinoides), golden shiner (Notemigonus crysoleucas), lake chub (Couesius plumbeus), spottail shiner (Notropis hudsonius), tessellated darter (Etheostoma nigrum olmstedi) and threespine stickleback (Gasterosteus aculeatus).
The reaches further upstream contain native, non-jumping species more typical of tributary habitat and include: central stoneroller (Campostoma anomalum), blacknose dace (Rhinichthys atratulus), bluntnose minnow (Pimephales notatus), creek chub (Semotilus atromaculatus), fathead minnow (Pimephales promelas), Johnny darter (Etheostoma nigrum), longnose dace (Rhinichthys cataractae), mottled sculpin (Cottus bairdi). Pond species have also been captured, likely sourced by online ponds, and include: pumpkinseed (Lepomis gibbosus), largemouth bass (Micropterus salmoides), rock bass (Ambloplites rupestris) and common carp (Cyprinus carpio).
The existing riverine communities in the upper reaches are similar to downstream reaches with the addition of more sensitive species (i.e., northern hog sucker (Hypentelium nigricans), northern redbelly dace (Chrosomus eos)) and a few wetland specialists (i.e., blacknose shiner (Notropis heterolepis) and central mudminnow (Umbra limi).
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The Mimico Creek watershed is also dominated by a similar suite of cool-warm water generalist species tolerant of a range of habitat conditions. However, Mimico lacks the headwater diversity and relatively greater abundance of fish reported for Etobicoke Creek. Lake-based diversity is evident in lower reaches of Mimico Creek with the collection of the following species in and around the mouth (below the first barrier): alewife, American eel (Anguilla rostrata), black crappie (Pomoxis nigromaculatus), brown bullhead, emerald shiner, freshwater drum (Aplodinotus grunniens), gizzard shad (Dorosoma cepedianum), lake chub, northern pike (Esox lucius), smallmouth bass (Micropterus dolomieui), spottail shiner, tessellated darter, trout-perch (Percopsis omiscomaycus) and white perch (Morone americana)
Within the lower half of Mimico Creek, rainbow trout and brown trout (stocked in neighbouring watersheds) have been collected upstream of the first couple of barriers as have migratory white sucker and common shiner. This is evidence that these structures are passable if seasonal water levels are high enough. The further upstream reaches contain native species including: blacknose dace, bluntnose minnow, creek chub, fathead minnow, Johnny darter, largemouth bass, longnose dace, pumpkinseed, rock bass, and common shiner. Invasive species in the system include, goldfish (Carassius auratus), round goby (Neogobius melanostomus) and common carp.
The upper subwatershed and headwaters are populated by the same suite of non-jumping, generalist species and in lower reaches, the only addition is brook stickleback (Culaea inconstans) indicative of ponded and temporary waters. Abundance as well as diversity is very low. Species that represented more specialized habitat and/or greater sensitivity have not been collected in the Mimico for many decades (e.g., sand shiner (Notropis stramineus) and blackchin shiner (Notropis heterodon).
9.4.2 On-Line Stormwater Management Ponds in the Etobicoke and Mimico Creeks Watersheds On-line stormwater management (SWM) ponds can present a fish passage issue as an instream structure is needed to create the pond feature. Additional impacts associated with on- line ponds are elevated stream temperatures and potential flushing of fine sediment and /or contaminants during storm events. This barrier assessment report will not include SWM ponds as a category of barrier subject to management for the purposes of fish passage. The Stormwater Management and Streamflow Section provides a full history and characterization of SWM facilities in the Etobicoke and Mimico Creeks watersheds. Management direction for SWM ponds will follow from that report (e.g., retrofit opportunities), however, should efforts address cumulative impacts of ponds and be coupled with barrier mitigation identified in this assessment, then benefits to fish and fish habitat would increase. The following discussion is based on information provided in the Stormwater Management and Streamflow Section.
Within the entire Etobicoke Creek watershed, there are only seven on-line stormwater management ponds making this issue relatively small (see Figure 9-4). Three of these are located in close proximity to each other within the Etobicoke Creek West Branch, north of Bovaird Drive East making cumulative impacts around passage, water quality and temperature of concern. The other four on-line ponds are distributed across three stream reaches (two in Tributary 3; one in the headwaters of Little Etobicoke Creek; one in the upper portion of Etobicoke Creek East branch).
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Within the Mimico Creek watershed, there are even fewer on-line stormwater ponds (total of three), as compared to the Etobicoke Creek watershed. They are all located in sequence, downstream through the upper reaches making localized cumulative impacts a concern. There is a new stormwater management pond being planned on the east branch of Mimico Creek but it will be constructed off-line.
9.4.3 Channelization of Etobicoke and Mimico Creeks In the past, streams were channelized as a measure of flood and erosion control. The ecological impacts of channelized watercourses include the removal of natural substrate and riffle-pool sequences which are important components of fish habitat. Channelization also may create conditions of sheet flow over drop structures or along the channelized portion itself creating a barrier to fish movement. In addition, channelization increases flow velocity during storm events which can contribute to accelerated erosion processes downstream. The lack of structure in the channelized section, coupled with velocity, means often barriers or no habitat for fish.
Etobicoke Creek has many channelized watercourses which include portions of Spring Creek, Etobicoke Creek West Branch, Tributary 3 and Little Etobicoke Creek. The Mimico Creek has relatively less channelization in the lower half of the watershed, but much of the headwaters and most major highway crossings have been hardened (see Figure 9-5).
Toronto Region Conservation, 2010 9-10 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Figure 9-4: Location of On-line Stormwater Management Ponds in Etobicoke and Mimico Creeks Watersheds
Toronto Region Conservation, 2010 9-11 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Figure 9-5: Channelized Streambed of Etobicoke and Mimico Creeks Watersheds
Toronto Region Conservation, 2010 9-12 Etobicoke and Mimico Creeks Watersheds Technical Update Report
9.4.4 Impervious Cover in Etobicoke and Mimico Creeks Watersheds In addition to low infiltration potential of surficial geology found in the Etobicoke and Mimico Creeks watersheds (see Study Area and Physical Setting Section), urban development has further increased the amount of impervious cover in both these watersheds. Watershed areas with a low percent impervious cover have more natural flow regimes as compared to high percent impervious cover which have more flashy flows. Studies have indicated that percent impervious cover above 10% can have negative effects on fish diversity and can reduce biotic integrity due to changes in the natural flow regime of the watercourse (Paul and Meyer, 2001). Changes in fish assemblage composition and feeding ecology have also been linked with percent impervious cover as low as 10-15% (Schueler, 1994, Paul and Meyer, 2001, Walters et al., 2003, Weaver and Garman, 1994, Poff and Allan, 1995; Wang et.al., 2000, Roy et.al., 2005).
A percent impervious cover assessment, completed in 2008, indicated a value greater than 15% impervious cover for the Etobicoke Creek watershed, with the exception of the headwaters Figure 9-6. Figure 9-7 shows low percent impervious cover (<10%) in the headwaters of Etobicoke West Branch which translates to a natural flow regime characterized by seasonally high flows (spring and fall) and lower flows throughout the summer months. In comparison, the Lower Etobicoke Creek has relatively higher impervious cover (26 - 65%) resulting in altered seasonal hydrology (see Figure 9-8).
This same percent impervious cover assessment showed Mimico Creek watershed at 57% impervious cover (see Figure 9-6). The only historic flow data available for the Mimico Creek watershed is from a stream gauge near the bottom of the watershed at the QEW. Figure 9-9 also depicts significant alteration in seasonal hydrology. What is also apparent in the flow data are high peaks in stream flow volume. During the 2009 barrier survey, field crews observed flash storm events, at various locations across the watershed, that resulted in streams filling to near or over capacity within minutes and then receding relatively quickly. This is further evidence of a system that has very little water retention function left. To adapt to this flashy condition, only fish species able to utilize the habitat created by constant scouring and withstand the flows themselves are persisting.
Toronto Region Conservation, 2010 9-13 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Figure 9-6: Percent Impervious Cover in Etobicoke and Mimico Creeks Watersheds, 2008
Toronto Region Conservation, 2010 9-14 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Figure 9-7: Natural Flow in Etobicoke West Figure 9-8: Impacted Flow in Lower Etobicoke Branch Subwatershed Subwatershed
Figure 9-9: Impacted Flow in Mimico Creek Watershed
Toronto Region Conservation, 2010 9-15 Etobicoke and Mimico Creeks Watersheds Technical Update Report
9.4.5 Overview of Barriers within Etobicoke Creek Watershed The instream barrier assessment for Etobicoke Creek watershed started in 2005 and was completed in August of 2008. Climatic conditions in 2008 were marked by a particularly wet summer; field work was undertaken during low flow conditions to the extent possible. The assessment confirmed the presence of 513 instream structures within 150 km of watercourse. Of the 513 instream structures, 179 were barriers to non-jumping fish species, and from those, 125 barriers prevented passage of jumping species (see Table 9-2 and Figure 9-10). The placement of some stormwater outfalls were barriers but were not included in the assessment as there was no upstream habitat present should fish gain access into the outfall pipe; this was effectively the end of the watercourse.
Table 9-2: Summary of Etobicoke Creek Instream Barrier Assessment (2005-2008)
Etobicoke Creek Structure Type Instream Structures Barriers To Non- Subset Number of Barriers Assessed Jumping Fish Passage to Jumping Species* Dam 15 11 10 Damaged Infrastructure 0 0 0 Natural Barrier 41 29 25 Other 9 0 0 Pedestrian Crossing 92 6 5 Railway Crossing 7 1 0 Road Crossing 226 25 25 Weir 123 107 60 Total 513 179 125 * would still be barriers to non-jumping species
Toronto Region Conservation, 2010 9-16 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Figure 9-10: Existing Instream Structures - Etobicoke Creek Watershed
Toronto Region Conservation, 2010 9-17 Etobicoke and Mimico Creeks Watersheds Technical Update Report
For discussion purposes barrier assessment results have been grouped together by subwatersheds. Discussions are provided for four subwatershed groups, comprising several subwatersheds as described in the following sections.
Subwatershed Groups
Lower Etobicoke Subwatershed Group - Lower Etobicoke, Etobicoke Main Branch, and Tributary 4 subwatersheds Little Etobicoke Subwatershed Group - Little Etobicoke Creek subwatershed
Spring Creek Subwatershed Group - Spring Creek subwatershed including the Bramalea tributaries Upper Etobicoke Subwatershed Group - Tributary 3, Etobicoke West Branch, and Etobicoke Headwaters subwatersheds
9.4.5.1 Lower Etobicoke Subwatershed Group This discussion focuses on instream structures found within three subwatersheds: Lower Etobicoke, Etobicoke Main Branch and Tributary 4. Within the 26.4 km of watercourse assessed (combined distance) there are a total of 97 instream structures, of which 34 prevent passage for non-jumping species and 27 of those prevent the passage of jumping species (see Figure 9-11 and Table 9-3).
Lower Etobicoke and Etobicoke Main Branch Etobicoke Creek flows through the Lower Etobicoke and Etobicoke Main Branch subwatersheds and into Lake Ontario but has a high degree of fragmentation (see Figure 9-11 and Table 9-3). Overall this watercourse has good vegetative cover; however, erosion of the stream bed is evident by the exposed shale in the lower reaches. Within the 18.1 km of stream assessed, there are 49 instream structures, of which there are 13 structures which prevent non- jumping species passage and 9 of those also prevent passage for jumping species. The majority of these barriers are weirs (4) and natural structures (4) as well as road crossings (3) and pedestrian crossings (2) (see Table 9-3).
The first barrier upstream of Lake Ontario is a weir located on the Toronto Golf Club. The weir likely prevents migration of salmonid species and native non-jumping, lake-based species when flows are not high enough. However, the weir can also prevent the upward migration of aquatic invasive species such as sea lamprey (Petromyzon marinus) and round goby, neither of which has been collected nor anecdotally observed in the watershed to date.
Toronto Region Conservation, 2010 9-18 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Figure 9-11: Lower Etobicoke Existing Instream Structures, including: Etobicoke Main Branch, Tributary 4, and Little Etobicoke
Toronto Region Conservation, 2010 9-19 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Table 9-3: Lower Etobicoke and Etobicoke Main Branch Subwatersheds, Instream Barrier Assessment (2005) Lower Etobicoke and Etobicoke Main Branch Subwatersheds Instream Structures Barriers To Non- Subset Number Barriers Structure Type Assessed Jumping Fish Passage to Jumping Species * Dam 0 0 0 Damaged Infrastructure 0 0 0 Natural Barrier 10 4 2 Other 0 0 0 Pedestrian Crossing 16 2 2 Railway Crossing 2 0 0 Road Crossing 16 3 3 Weir 5 4 2 Total 49 13 9 *would still be barriers to non-jumping species
Tributary 4 The watercourse flowing through the Tributary 4 subwatershed is approximately half the length of Etobicoke Creek but contains a similar number of barriers (see Figure 9-11 and Table 9-4). Of the approximately 8.3 km of watercourse assessed, there are a total of 48 instream structures, 20 of which are barriers to non-jumping and 17 of those also prevent movement of jumping species (see Table 9-4). Barrier types include dams (6), road crossings (5), weirs (4), natural barriers (3), and pedestrian crossings (2).
Three of the six dams are within the first 200 m of the confluence of Tributary 4 and Etobicoke Creek, all located on the Markland Wood Country Club property. These dams are of sufficient height to prevent the passage of all fish species. Several of the weir structures have created on- line ponds in the headwaters of Tributary 4 which may be warming the stream. Common carp and koi were observed in these ponds adding to the detrimental effects on in-pond and downstream habitat quality. In large part, the watercourse has a natural stream bed, but is lacking riparian vegetation. Other species collected within Tributary 4 are limited to three tolerant species: blacknose dace, creek chub, and fathead minnow.
Table 9-4: Tributary 4 Subwatershed, Instream Barrier Assessment (2005) Tributary 4 Instream Structures Barriers To Non- Subset Number Barriers Structure Type Assessed Jumping Fish Passage to Jumping Species * Dam 6 6 5 Damaged Infrastructure 1 0 0 Natural Barrier 4 3 3 Other 0 0 0 Pedestrian Crossing 17 2 1 Railway Crossing 0 0 0 Road Crossing 14 5 5 Weir 6 4 3 Total 48 20 17 * would still be barriers to non-jumping species
Toronto Region Conservation, 2010 9-20 Etobicoke and Mimico Creeks Watersheds Technical Update Report
9.4.5.2 Little Etobicoke Subwatershed Group The Little Etobicoke Creek flows through the western portion of the watershed and drains into the Lower Etobicoke Creek (see Figure 9-11 and Table 9-5). Within approximately 14.2 km of stream, there are 73 instream structures, 42 of which are barriers to non-jumping passage and 22 of those also prevent the movement of jumping species (see Table 9-5). Weirs represent the largest proportion of instream barriers, totaling 33. There are also natural barriers (6), damaged infrastructure (1), a pedestrian crossing (1) and a railway crossing (1) preventing passage for non- jumping species. Erosion of the streambed downstream of anthropogenic structures has led to the creation of four “steps” (categorized as weirs for the assessment) which prevent passage of all species. The biggest ‘step’ or drop is immediately downstream of the CN railway structure (see Figure 9-12).
In addition to severe habitat fragmentation, streambed erosion down to bedrock is observed in the lower reaches. Little Etobicoke Creek has the benefit of mature vegetative cover, however the degree of fragmentation and lack of instream habitat presents challenges to system function.
Little Etobicoke Creek was last sampled in 1985 and 1991 characterizing it as a highly degraded system with the following tolerant species collected: blacknose dace, bluntnose minnow, common shiner, creek chub, fathead minnow, longnose dace, rock bass, and white sucker.
Table 9-5: Little Etobicoke Subwatershed, Instream Barrier Assessment (2005) Little Etobicoke Subwatershed Structure Type Instream Structures Barriers To Non- Subset Number Barriers Assessed Jumping Fish Passage to Jumping Species * Dam 0 0 0 Damaged Infrastructure 1 1 1 Natural Barrier 10 6 4 Other 3 0 0 Pedestrian Crossing 6 0 0 Railway Crossing 1 1 0 Road Crossing 15 1 1 Weir 40 33 16 Total 73 42 22 * would still be barriers to non-jumping species
Figure 9-12: Weir at CN Railway Line
Toronto Region Conservation, 2010 9-21 Etobicoke and Mimico Creeks Watersheds Technical Update Report
9.4.5.3 Spring Creek Subwatershed Group Spring Creek flows along the east side of the watershed and drains into the confluence with Etobicoke Creek Main Branch and Etobicoke Creek West Branch. Spring Creek includes a section of tributaries which are, for the purpose of this report, referred to as the Bramalea tributaries (see Figure 9-13 and Table 9-6). Over approximately 35.9 km, there are 152 instream structures, 59 are barriers to non-jumping fish passage and of those 36 also prevent the movement of jumping species (see Table 9-6). Weirs were the dominant structure restricting passage, totaling 51. Road crossings (6), damaged infrastructure (1) and a dam (1) are also barriers. In general, when comparing the main branch of Spring Creek to the Bramalea tributaries, Spring Creek offers more natural stream bed and higher quality fish habitat.
Species collected in Spring Creek are dominantly non-jumping species which include brown bullhead, golden shiner, central mudminnow, blacknose dace, bluntnose minnow, common shiner, creek chub, fathead minnow, fathead minnow, golden shiner, green sunfish, Johnny darter, longnose dace, pumpkinseed, central stoneroller, and white sucker. Because of a stocking program at the Heart Lake Conservation Area, rainbow trout have been collected in this subwatershed likely reflecting escaped fish and not suitable coldwater habitat conditions.
Table 9-6: Total Spring Creek Subwatershed, Instream Barrier Assessment (2008) Etobicoke Creek East Branch and Spring Creek Structure Type Instream Structures Barriers To Non- Subset Number Barriers Assessed Jumping Fish Passage to Jumping Species * Dam 2 1 1 Damaged Infrastructure 2 1 0 Natural Barrier 0 0 0 Other 4 0 0 Pedestrian Crossing 22 0 0 Railway Crossing 2 0 0 Road Crossing 72 6 6 Weir 52 51 29 Total 152 59 36 * would still be barriers to non-jumping species
Main Branch of Spring Creek The main branch of Spring Creek flows along the east side of the Spring Creek subwatershed. The watercourse is highly fragmented by weirs. Channelization is extensive creating sheet flow conditions. Within approximately 21.9 km of watercourse, there are 80 instream structures, 27 of which were barriers to non-jumping species and 11 of those also prevent passage of jumping species. The majority of barriers are weirs (23) followed by road crossings (3) and a dam (1) (Table 9-7). There is a concentration of 16 weirs within only 1.5 km of straightened and channelized stream starting from the confluence of where the main branch of Spring Creek meets the Bramalea tributaries (Figure 9-13 and Table 9-7).
Toronto Region Conservation, 2010 9-22 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Figure 9-13: Spring Creek Existing Instream Structures within Spring Creek Subwatershed
Toronto Region Conservation, 2010 9-23 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Erosion is observed upstream of the confluence of Spring Creek and Etobicoke Creek West Branch (see Figure 9-14). The Chinguacousy Dam prevents passage to the relatively good habitat still remaining in the upper reaches of Spring Creek (see Figure 9-15). Upstream of Chinguacousy Park dam channelized stream bed exists for 1.4 km but is then followed by 3.9 km of natural stream bed containing no barriers. There is wetland habitat in the north-west headwater tributary, partly located within Heart Lake Conservation Area, but a large instream barrier fragments passage from stream through to wetland. In general, riparian vegetation is absent in the lower reaches of this system and sparse in the upper reaches.
Table 9-7: Main Branch of Spring Creek Subwatershed, Instream Barrier Assessment (2008) Main Branch of Spring Creek Instream Structures Barriers To Non- Subset Number Barriers Structure Type Assessed Jumping Fish Passage to Jumping Species* Dam 2 1 1 Damaged Infrastructure 0 0 0 Natural Barrier 0 0 0 Other 0 0 0 Pedestrian Crossing 14 0 0 Railway Crossing 1 0 0 Road Crossing 40 3 3 Weir 23 23 7 Total 80 27 11 * would still be barriers to non-jumping species
Figure 9-14: Erosion North-East of Drew Figure 9-15: Chinguacousy Park Dam Road and Bramalea Road North-West of Queen Street and Central Park Road
Toronto Region Conservation, 2010 9-24 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Bramalea Tributaries For the purposes of this report, the Bramalea Tributaries have been named, Bramalea - Avondale, Bramalea - West, Bramalea - Clark, and Bramalea - Orenda and collectively measure a total of 12.8 km watercourses. The Bramalea tributaries contain 9.4 km of channelized watercourse and exist in a highly urbanized area. Across all the tributaries, there are 68 instream structures, 30 of which are barriers to non-jumping fish and 24 of those also prevent passage of jumping fish species. Weirs are the dominant barrier type (26) followed by road crossings, which are all perched culverts (3) and damaged infrastructure (1) (Table 9-8 and Figure 9-13). Passage up into these tributaries, from Etobicoke Creek East Branch, is blocked for all fish species, under low flow, by a weir at the bottom of the Bramalea - Avondale and Bramalea - Orenda tributaries (SPBROR002). Only blacknose dace and Johnny darter have been collected within these tributaries.
Table 9-8: Bramalea Tributaries within Spring Creek Subwatershed, Instream Barrier Assessment (2008) Bramalea Tributaries Instream Structures Barriers To Non- Subset Number Barriers Structure Type Assessed Jumping Fish Passage to Jumping Species * Dam 0 0 0 Damaged Infrastructure 2 1 0 Natural Barrier 0 0 0 Other 0 0 0 Pedestrian Crossing 8 0 0 Railway Crossing 1 0 0 Road Crossing 30 3 3 Weir 27 26 21 Total 68 30 24 * would still be barriers to non-jumping species
The Bramalea – Avondale tributary (SPBRAV) is channelized for its entire 5.0 Figure 9-16: Channel Erosion at Avondale km reach and contains 37 instream Tributary at Dixie and Clarke structures of which 17 are barriers to non- jumping fish, of which 13 also prevent jumping species passage . In this tributary, erosion of the stream banks and damaged infrastructure was observed where the channelization ended (Figure 9-16).
Toronto Region Conservation, 2010 9-25 Etobicoke and Mimico Creeks Watersheds Technical Update Report
9.4.5.4 Upper Etobicoke Subwatershed Group The Upper Etobicoke subwatershed group consists of Tributary 3, Etobicoke Creek West Branch and Etobicoke Creek Headwaters. All flows eventually combine and drain into the Lower Etobicoke Main Branch north-west of Britannia Road and Dixie Road (see Figure 9-17).
Tributary 3 Tributary 3 includes three small watercourses that are referred to as east, central and west tributaries. A combined total of approximately 14.9 km of stream length contains 40 instream structures of which 12 prevent non-jumping fish passage and of those, 8 also prevent passage of jumping fish species (see Table 9-9). There are 8 weirs and 4 pedestrian crossings (all perched culverts) which prevent the passage of non-jumping species. The small tributaries all have minimal barrier issues relative to the other Etobicoke Creek watercourses but they all flow through heavily industrialized land use.
At the furthest downstream portion of Tributary 3, there is a large flow dissapating weir structure that obstructs fish passage into the east, central and west tributaries (Figure 9-18). Fish sampling below this structure (2000-2007) confirmed the presence of blacknose dace, brook stickleback, creek chub, fathead minnow and longnose dace. During the 2008 field work, dipnetting efforts collected only blacknose dace and Johnny darter above this structure.
The West Tributary is the most fragmented within the Tributary 3 system with 7 barriers (all weirs). Only one of these weirs is likely passable when the water flow is high enough (Figure 9-19). Although there is much riparian vegetation along the West Tributary, much of the stream bed is channelized and sheet flow impedes fish movement.
The Central Tributary has passable structures all the way through until the very upstream reach where 4 perched culverts (pedestrian crossings) exist within Brampton Golf Course property. This tributary also has a channelized riverbed downstream of the Brampton Golf course property with sedimentation issues at highway crossings.
The East Tributary has no passage issues, however, flow volume is low and fish habitat is poor due to heavy sedimentation and minimal riparian vegetation.
Table 9-9: Tributary 3 Subwatershed, Instream Barrier Assessment (2008) Tributary 3 Subwatershed Instream Structures Barriers To Non- Subset Number Barriers Structure Type Assessed Jumping Fish Passage to Jumping Species * Dam 0 0 0 Damaged Infrastructure 0 0 0 Natural Barrier 0 0 0 Other 0 0 0 Pedestrian Crossing 6 4 4 Railway Crossing 0 0 0 Road Crossing 22 0 0 Weir 12 8 4 Total 40 12 8 * would still be barriers to non-jumping species
Toronto Region Conservation, 2010 9-26 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Figure 9-17: Upper Etobicoke Existing Instream Structures including: Tributary 3, Etobicoke West Branch and Etobicoke Headwaters Subwatersheds
Toronto Region Conservation, 2010 9-27 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Figure 9-18: Flow Dissipating Weir in Tributary 3 South-West of Midway Boulevard and Dixie Road
Figure 9-19: Weir Structure in West Tributary located North-West of Courtney Park Drive and Tomken Road in 2006(a) low flow and 2008 (b) high flow.
Etobicoke West Branch The Etobicoke Creek West Branch flows from the headwaters, receives flow from Tributary 3 and then confluences with the Etobicoke Creek Main Branch (see Figure 9-17). Within approximately 23.6 km of watercourse, there are 48 instream structures, but only 7 of which prevent non-jumping passage and of those, only 3 barriers prevent jumping fish passage. Barrier types are weirs (3), road crossings (2), a natural barrier (1) and a pedestrian crossing (1) (Table 9-10). Channelization occurs for approximately 200 m of the 23.6 km. The majority of anthropogenic barriers exist within a small side tributary north-east of Derry Road and Dixie Road one of which is a large three step weir which prevents passage for all fish species (see Figure 9-20). This side tributary also ends with a perched culvert (see Figure 9-21). Thus, within the main Etobicoke Creek West Branch itself, there is only one human-made barrier, a weir just south of Queen Street (MEE023) that prevents passage to the headwaters.
Riparian vegetation is sparse in the lower section of the Etobicoke Creek West Branch, however good vegetative cover occurs frequently upstream of the 407/ 410 intersection and increases towards the headwaters. Erosion was observed mainly in the lower reaches.
Fish sampling in 2001, 2004, and 2007 collected non-jumping species including, blacknose dace, bluntnose minnow, brook stickleback, common shiner, creek chub, fathead minnow,
Toronto Region Conservation, 2010 9-28 Etobicoke and Mimico Creeks Watersheds Technical Update Report
goldfish, Johnny darter, longnose dace, northern hog sucker, rock bass, stone roller, brown bullhead and spottail shiner. Upstream of this barrier golden shiner, pumpkin seed and white sucker were collected.
Table 9-10: Etobicoke West Branch, Instream Barrier Assessment (2008) Etobicoke West Branch Instream Structures Barriers To Non- Subset Number Barriers Structure Type Assessed Jumping Fish Passage to Jumping Species * Dam 1 0 0 Infrastructure Damage 0 0 0 Natural Barrier 1 1 1 Other 0 0 0 Pedestrian Crossing 18 1 0 Railway Crossing 1 0 0 Road Crossing 24 2 0 Weir 3 3 2 Total 48 7 3 * would still be barriers to non-jumping species
Figure 9-20: Step Weir at Drew Road East of Figure 9-21: Perched Culvert North of 407 Dixie Road. West of Dixie Road.
Etobicoke Headwaters Within the Etobicoke Creek Headwaters, approximately 50.6 km of watercourse contains 101 instream structures with only 37 identified as barriers to fish passage; the lowest number compared to other watercourses of similar length (see Table 9-11 and Figure 9-17). However, 36 of the 37 barriers prevent movement of all species. The assessment identified road crossings (many perched culverts) to be the most common barriers (20) followed by natural barriers (15) and weirs (2). Many of the smaller headwater tributaries were dry at the time of assessment, limiting fish habitat during summer months. The stream bed remained natural throughout all tributaries assessed.
Fish sampling in 2001, 2004 and 2007 collected brown bullhead, golden shiner, pearl dace; blacknose dace, blacknose shiner, bluntnose minnow, brook stickleback, common shiner, creek chub, fantail darter (Etheostoma flabellare), fathead minnow, golden shiner, Johnny
Toronto Region Conservation, 2010 9-29 Etobicoke and Mimico Creeks Watersheds Technical Update Report
darter, northern redbelly dace, pumpkinseed, rock bass, spottail shiner, white sucker and the wetland species central mudminnow.
Table 9-11: Summary of Etobicoke Creek Headwaters Instream Barrier Assessment (2008) Etobicoke Creek Headwaters Instream Structures Barriers To Non- Subset Number Barriers Structure Type Assessed Jumping Fish Passage to Jumping Species * Dam 0 0 0 Damaged Infrastructure 0 0 0 Natural Barrier 16 15 15 Other 2 0 0 Pedestrian Crossing 15 0 0 Railway Crossing 1 0 0 Road Crossing 64 20 19 Weir 3 2 2 Total 101 37 36 * would still be barriers to non-jumping species
9.4.6 Overview of Barriers within Mimico Creek Watershed The instream barrier assessment for Mimico Creek watershed started in June 2009 and was completed September 2009. The assessment of the Mimico Creek watershed occurred during low flow conditions to the extent possible, as climatic conditions produced an even wetter year than 2008. The assessment confirmed the presence of 338 instream structures along 57.2 km of watercourse. Of the 338 instream structures, 145 are barriers to non-jumping fish species, and from those, 126 barriers prevent passage of jumping species (see Table 9-12 and Figure 9-22). Stormwater outfalls were barriers but were not included in the assessment when upstream habitat was not present.
Table 9-12: Summary of Mimico Creek Instream Barrier Assessment (2009) Mimico Creek Structure Type Instream Structures Barriers To Non- Subset Number of Barriers Assessed Jumping Fish Passage to Jumping Species* Dam 0 0 0 Damaged Infrastructure 9 56 55 Natural Barrier 54 27 25 Other 11 9 8 Pedestrian Crossing 74 1 0 Railway Crossing 20 6 5 Road Crossing 76 13 12 Weir 94 87 71 Total 338 145 126 * would still be barriers to non-jumping species
The Mimico Creek system was not divided into subwatersheds. For the purpose of this barrier report, results are organized and discussed in 3 groups: (1) Mimico Creek Main Branch, (2) Mimico Creek East Branch, (3) Mimico Creek West Branch.
Toronto Region Conservation, 2010 9-30 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Figure 9-22: Existing Instream Structures in Mimico Creek Watershed
Toronto Region Conservation, 2010 9-31 Etobicoke and Mimico Creeks Watersheds Technical Update Report
9.4.6.1 Mimico Creek Main Branch This discussion focuses on instream structures found within 22.6 km of the main branch of Mimico Creek (see Figure 9-23). There are a total of 97 instream structures, of which 21 prevent non-jumping species passage and 10 of those prevent the passage of jumping species (see Table 9-13). Weirs represent the largest proportion of instream barriers for non-jumping fish, totaling 11, all within the main branch of Mimico Creek. Five natural barriers occur in a small tributary called Bonar Creek, located near the mouth of the Mimico Creek. Overall the watercourse has good vegetative cover; however, erosion of the stream bed, either natural or accelerated by the altered flow regime, is evident by the exposed shale through the lower reaches.
The first barriers up from the lake are 2 weirs, in very close proximity to each other, just below the QEW. Reviewing past and present fish records suggests that the migratory species, both jumping and non-jumping, are able to get past these structures but likely only when water levels are seasonally high. There is no evidence to support non-migratory lake-based species (e.g., emerald shiner, tesselated darter, alewife, etc) can pass these weirs at any time. The positive corollary to that is aquatic invasive species (i.e., sea lamprey and round goby) should not be able to pass into the watershed.
Further up into the watershed, only a few native, tolerant warm water species are found and all in low numbers: blacknose dace, bluntnose minnow, brook stickleback, common shiner, creek chub, fathead minnow, Johnny darter, longnose dace. Goldfish were the only fish species observed in this branchduring the field survey in 2009.
Table 9-13: Mimico Creek Main Branch, Instream Barrier Assessment (2009) Mimico Creek Main Branch Instream Structures Barriers To Non- Subset Number Barriers Structure Type Assessed Jumping Fish Passage to Jumping Species * Dam 0 0 0 Damaged Infrastructure 0 0 0 Natural Barrier 8 5 4 Other 1 1 1 Pedestrian Crossing 43 1 0 Railway Crossing 5 0 0 Road Crossing 25 3 2 Weir 15 11 3 Total 97 21 10 * would still be barriers to non-jumping species
Toronto Region Conservation, 2010 9-32 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Figure 9-23: Existing Instream Structures in Mimico Creek Main Branch
Toronto Region Conservation, 2010 9-33 Etobicoke and Mimico Creeks Watersheds Technical Update Report
9.4.6.2 Mimico Creek East Branch This discussion focuses on the instream structures found within 20.6 km of the east branch of Mimico Creek (see Figure 9-24). There are a total of 135 instream structures of which 79 structures prevent non-jumping species passage and of those, 75 are barriers to jumping species. Weirs represented the largest proportion of instream barriers for non-jumping fish, totaling 56. There are also road crossings (7), natural barriers (7), railway crossings (4), damaged infrastructure (3) and 2 other structures that do not fit into the standard categories (see Table 9-14 and Figure 9-24).
Table 9-14: Mimico Creek East Branch, Instream Barrier Assessment (2009) Mimico Creek East Branch Instream Structures Barriers To Non- Subset Number Barriers Structure Type Assessed Jumping Fish Passage to Jumping Species * Dam 0 0 0 Damaged Infrastructure 3 3 3 Natural Barrier 11 7 7 Other 3 2 2 Pedestrian Crossing 23 0 0 Railway Crossing 7 4 3 Road Crossing 30 7 7 Weir 58 56 53 Total 135 79 75 *would still be barriers to non-jumping species
Toronto Region Conservation, 2010 9-34 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Figure 9-24: Existing Instream Structures in Mimico Creek East Branch
Toronto Region Conservation, 2010 9-35 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Just upstream of the confluence of the two headwater tributaries are two active beaver dams that are barriers Figure 9-25: Damaged Infrastructure south- to all fish species during low flow conditions. Within west of Clark Blvd. and Walker Dr. (MCE 103) these headwaters, interlocking brick (i.e., terrafix blocks) and concrete line much of the streambed. This causes erosive flows that have broken apart instream engineered works and washed loosened material downstream. The result is 3 more barriers categorized as “damaged infrastructure” (see Figure 9-25). Unfortunately, copious amounts of garbage and urban debris also litter these small streams to the point of being partial barriers. Overall this watercourse has sparse vegetative cover.
9.4.6.3 Mimico Creek West Branch This discussion focuses on the instream structures found within 13.9 km of the West Branch of Mimico Creek. There are a total of 106 instream structures of which 48 structures prevent non- jumping species passage and of those, 41 are barriers to jumping species. Weirs are the main type of barriers to non-jumping fish, totaling 20, followed by natural barriers (15), other (5), road crossings (3), damaged infrastructure (3) and railway crossings (2) (see Table 9-15 and Figure 9-26). There is good riparian vegetative cover in patches, however, flows are not permanent as, even in a wet year, the small tributary near the confluence of the west branch and main branch was dry by August (2009). This West Branch also contains 2 barriers completely composed of garbage.
Fish records indicate the West Branch of Mimico Creek supports only low numbers of non- jumping tolerant species: brook stickleback, creek chub, fathead minnow, white sucker.
Table 9-15: Mimico Creek West Branch, Instream Barrier Assessment (2009) Mimico Creek West Branch Instream Structures Barriers To Non- Subset Number Barriers Structure Type Assessed Jumping Fish Passage to Jumping Species * Dam 0 0 0 Damaged Infrastructure 6 3 2 Natural Barrier 35 15 14 Other 7 5 5 Pedestrian Crossing 8 0 0 Railway Crossing 8 2 2 Road Crossing 21 3 3 Weir 21 20 15 Total 106 48 41 * would still be barriers to non-jumping species
Toronto Region Conservation, 2010 9-36 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Figure 9-26: Existing Instream Structures in Mimico Creek West Branch
Toronto Region Conservation, 2010 9-37 Etobicoke and Mimico Creeks Watersheds Technical Update Report
9.4.7 Overall Summary of Existing Conditions Within the Etobicoke Creek watershed, habitat fragmentation is greatest in Little Etobicoke Creek (total number of barriers 42) and Etobicoke Creek East Branch (Spring Creek system; total number of barriers 59). There are lengthy portions of the Etobicoke Creek West Branch that remain open with few anthropogenic barriers. When examining the watershed from a broader context, the healthiest areas are the headwaters where there is still relatively high fish abundance, diversity and better trophic structure. The numbers of barriers in the headwaters are minimal compared with other Etobicoke watercourses of similar length and with impervious cover relatively low, the flow regime is in a more natural state. Perched culverts are an issue in the headwaters under low flow but the remaining barriers occur due to naturally created conditions (e.g. beaver dams and log jams).
Within the Mimico Creek watershed, habitat fragmentation is a result of typical physical barriers but also heavily influenced by high flow velocities, damaged infrastructure and/or engineered instream works, major transportation infrastructure (i.e., highways and railway crossings), and urban debris. Unlike the Etobicoke Creek watershed, the greatest opportunities in Mimico Creek are within the lower half of the watershed, along the main branch. The main branch contains the most riparian vegetation, natural substrate and the lowest amount of barriers than either of the two headwater branches (East and West). Between the headwater branches, there are comparable lengths of natural substrate close to the confluence with the main stem and the West branch has recently undergone some naturalization in the upper reach, though portions are still channelized. However, the upper East branch is still predominately channelized with hardened banks. Throughout the headwaters, the hardened concrete channels have been deteriorating and creating effective barriers as the loosened material is washed downstream.
In addition, the Mimico Creek watershed contains the Q.E.W, 401, 409, 407, and 427 highways, as well as 20 railway crossings, 6 preventing the movement of fish, as compared to the Etobicoke Creek watershed that only has 7 such crossings with only 1 assessed as a barrier.
9.5 DECISION CRITERIA FOR SELECTING PRIORITIY BARRIERS FOR MANAGEMENT Identification and quantification of instream barriers is the first step towards improving fish passage, fish populations and the overall health of the watershed. The second step is the prioritization of barriers for management. Three management categories were defined and appear in priority sequence:
Category A: barriers identified in this highest priority group would, if removed or mitigated, achieve the overall watershed target of connecting Lake Ontario to the headwaters; barriers situated within the preferred passage route were all grouped into Category A in Etobicoke and Mimico Creeks and are presented in Sections 9.6.1 and 9.7.1, respectively.
Category B: barriers identified in this second priority group would, if removed or mitigated, improve connectivity within a subwatershed; barriers situated within the preferred passage routes for Category B in Etobicoke and Mimico Creeks and are presented in Sections 9.6.2 and 9.7.2, respectively.
Category C: barriers identified in this group, if removed, address fragmentation only at the reach level but provide stewardship opportunities; barriers identified for Category C in Etobicoke and Mimico Creeks and are presented in Sections 9.6.3 and 9.7.3, respectively.
Toronto Region Conservation, 2010 9-38 Etobicoke and Mimico Creeks Watersheds Technical Update Report
A variety of decision criteria were applied to sort barriers and ultimately populate the management categories. These are listed in Table 9-16 and explained below.
Table 9-16: Decision Criteria for Selecting Priority Barriers for Management
Ecological Criteria Category
Most direct route from the Lake to the headwaters that optimizes connections between reaches with relatively high biotic integrity (Fish IBI A scores) and/or existing natural stream habitat
Close proximity to other rehabilitation projects A & B
Extend/connect reaches with existing riparian vegetation in a subwatershed B Cultural Criteria
Only small scale barrier removal C
9.5.1 Fish IBI Scores and Natural Stream Habitat Areas Determination for barriers into Category A used the criteria of locating the most direct stream “route” from the Lake to the headwaters that optimizes connections between reaches with relatively high fish Index of Biotic Integrity (IBI) scores and/or existing natural stream habitat. The fish IBI is an ecologically-based measure of stream health based on the characteristics and interactions of the fish community. Parameters used to evaluate health include species richness, local indicator species, trophic composition and fish abundance. A scoring system is applied to rank sample sites into categories of “poor”, “fair” or “good”. Fish IBI scores for both the Etobicoke and Mimico Creeks for 2002 and 2005 are illustrated on Figure 9-27.
The Etobicoke Creek Headwaters scored an IBI rating of “good” in the past; and in recent years has been considered “fair”. The Etobicoke West Branch also scored an IBI rating of “good”. Spring Creek, Tributary 3, Etobicoke Main Branch and Lower Etobicoke subwatersheds have “poor” IBI ratings. The mouth of Etobicoke Creek achieved a higher rating as a result of Lake-influenced diversity (See Figure 9-27).
The only location in Mimico Creek that had a score of ‘good’ and ‘fair’ (2002 and 2005 respectively) was just upstream of the mouth, again a reflection of Lake-influenced diversity. All the West Mimico Branch sites were ‘poor’ in 2002 and 2005. All the sites in the Main and East Mimico Branches have declined from “poor” in 2002 to “no fish” in 2005. ”No fish” does not necessarily mean that all fish were extirpated from these streams, but that abundance may have become low enough that standard sampling methods did not capture them during the 2005 event.
There are streams, in both watersheds, that had no IBI scores specifically associated with them but good quality habitat was observed during field work, such as natural substrate, riffle-pool sequence, and thick vegetative cover. The combined presence of these features also implied a relatively natural flow regime (i.e., streams are not being ‘blown out’ or heavily eroded during storm events). Focusing on areas of the watershed where there are more “natural” flow regimes is the best hope for maintaining and improving a healthy aquatic ecosystem. Further evidence supporting these areas as more ecologically functional was through this Technical Update, that is, severe erosion sites were not identified within these natural habitat areas.
Toronto Region Conservation, 2010 9-39 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Figure 9-27: Index of Biotic Integrity - Etobicoke and Mimico Creeks Watersheds
Toronto Region Conservation, 2010 9-40 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Findings from the groundwater and surface water reports did not specifically inform the identification of quality areas beyond the higher scoring IBI sites and natural ones observed in the field. However, the potential increase in groundwater discharge noted in the highly fragmented, upper reaches of the Spring Creek (see Groundwater Quantity and Quality Section) may have positive, future implications for fish should summer baseflow volumes increase and/or stream warming trends be mitigated.
9.5.2 Rehabilitation Projects Determination of barriers into both Category A and Category B used the criterion of proximity to other rehabilitation projects. Ongoing rehabilitation or improvement projects provide an opportunity to complement barrier management efforts within the watersheds of Etobicoke and Mimico Creeks. Such projects include:
• Erosion Management Projects, • Sustainable Neighbourhood Retrofit Action Plan (SNAP), • Partners in Project Green–Eco-Industrial Park (PPG)
Locations of these ongoing projects are shown on Figure 9-28. The erosion management projects have direct effects on the watercourse, increasing bank stability and improving substrates. In the Etobicoke Creek watershed, the Sustainable Neighbourhood Retrofit Action Plan and the projects initiated by Partners in Project Green improve aquatic habitat through land-based initiatives. One of the many projects within the Partners in Project Green initiative includes increasing the perviousness of parking lots to better infiltrate rainwater. This contributes cleaner water to streams via shallow groundwater seepage. These projects are referred to as “greening parking lots”.
The Upper Mimico Creek Aquatic Habitat Implementation Project has been ongoing since 2007. This project is a joint effort between the Regional Municipality of Peel and TRCA that is naturalizing 1.2 km of the Mimico Creek north-west of Hwy 407 and Airport Road. This straightened and channelized section is being redesigned to consist of naturalized stream bed with riffle-pool sequences. Through the development of a wetland area, this restoration will also better attenuate flows that were causing significant downstream erosion.
There are many terrestrial restoration priorities identified in the Terrestrial Natural Heritage System Section. These are proposed works that, should they be undertaken, would have a benefit to the aquatic system as well. For this report, when aligning priority barrier selection with restoration projects, greater weight was given to those terrestrial initiatives already underway or within the active planning stages, however, due consideration was given to areas of terrestrial priority.
Potential stormwater pond outlet mitigation efforts were not used as a decision criterion for specifically improving connectivity as the ponds in question are offline and works would not afford passage to any upstream habitat. However, depending on the type of any mitigation, improved stream temperatures or water quality would enhance general stream habitat conditions. Locations and/or effects of such stormwater pond retrofits, along with other future rehabilitation projects, should be considered as barrier mitigation strategies move forward into more detailed design.
Toronto Region Conservation, 2010 9-41 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Figure 9-28: Rehabilitation Projects – Etobicoke and Mimico Creeks Watersheds (2009)
Toronto Region Conservation, 2010 9-42 Etobicoke and Mimico Creeks Watersheds Technical Update Report
9.5.3 Riparian Vegetation Cover Determination of barriers into Category B used the criterion of existing riparian vegetation (any community) within a subwatershed based on field observations and assessment mapping (see Figure 9-29). Vegetation proximate to streams increases leaf litter and terrestrial invertebrates which are important to the foundation of the aquatic food web, and as well, the cover reduces thermal intensity during the summer (Cummins, 1974; Cummins, 1979; Jenkins et al., 1984; Gibson and Power, 1975; Milner et al., 1981, In Brooker, 1985). This is a similar criterion to the natural stream habitat areas used for Category A, but many of the smaller tributaries did not have much instream habitat features due to, for example, channelizaton or scouring flows. However, riparian vegetation was a reasonable consistent metric amongst these streams (see Figure 9-29).
9.5.4 Small Scale Barriers Determination of barriers into Category C used the criteria of the size and nature of the stream ‘blockage’. This acknowledges the importance of stewardship opportunities at the community level by selecting barriers which appear ‘easy’ to remove at ‘low cost’ to achieve local enhancement. Examples of such opportunities could include garbage and defunct snow fencing removal.
Toronto Region Conservation, 2010 9-43 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Figure 9-29: Riparian Cover for Etobicoke and Mimico Creeks Watersheds
Toronto Region Conservation, 2010 9-44 Etobicoke and Mimico Creeks Watersheds Technical Update Report
9.6 MANAGEMENT RECOMMENDATIONS –ETOBICOKE CREEK PRIORITY BARRIERS In addition to the set of decision criteria described in the previous section, these recommendations follow the emphasized importance of protecting and enhancing the relatively healthy headwaters of Etobicoke Creek described in the Turning over a new leaf: The Etobicoke and Mimico Creeks Watersheds Report Card 2006 (TRCA, 2006).
Findings from the other component updates have been considered, especially if management priorities were set and/or existing conditions had specific implications to the aquatic system (e.g., groundwater enhancement). As discussed in the Stormwater Management and Streamflow Section, potential retrofits will be guided by the Technical Update, however, should future planning direction include removal of SWM ponds that are spatially close together (e.g., within Etobicoke Creek West Branch north of Bovaird Drive), this would serve to enhance the benefits of mitigating barriers within the same system.
It is important to state that before any instream barrier management work is undertaken, the overall hydrological conditions and flow regime of the upstream catchment must be fully characterized and assessed to properly gauge the effects of barrier removal or mitigation. Also important is to reiterate that the following recommendations do not preclude obtaining the required approvals and permits needed under existing legislation.
9.6.1 Category A - Lake to Headwaters With determining the most direct route from Lake Ontario to the headwaters of Etobicoke Creek that maximizes habitat potential, a total of 8 barriers were identified for Category A Priority Management. Non-jumping species can not pass any of the barriers (under low flow) and only 2 of them are passable by jumping species (Table 9-17 and Figure 9-30). Management of these barriers would connect approximately 50 km of watercourse with the addition of the headwater tributaries. This approach capitalizes on the natural stream bed and good riparian cover which occurs along a substantial amount of the selected route. This section would also link areas of “good” biotic integrity in the Etobicoke Creek West Branch to the “good” biotic integrity found in the headwaters. The majority of the barriers are weirs (5) with the remaining ones being beaver dams (3). The following section provides greater detail on these priority barriers.
Table 9-17: Etobicoke Creek Priority Barriers for Management Category A Instream Structure and Location Passage 1. Weir at Toronto Golf Club (ECLOW006) No Passage 2. Weir 500 m south of Q.E.W bridge (ECLOW011) Jumping Species Only 3. Weir at Bloor St. west of Mill Rd. (ECLOW029) No Passage 4. Weir at Britannia Rd. east of Dixie Rd. (ECLOW039) Jumping Species Only 5. Weir south of Queen St. (MEE023) No Passage 6. Beaver dam in Weybridge Park (MEE033) No Passage 7. Beaver dam near Valleywood Development (MEE059) No Passage 8. Beaver dam north of Mayfield between Hurontario & Kennedy (MEE060) No Passage
Toronto Region Conservation, 2010 9-45 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Figure 9-30: Priority Category A – Lake to Headwaters- Etobicoke Creek Watershed *
*Management recommendations are based on ecological benefit only. Approvals and Permits may be required under other existing legislation. Feasibility studies may also be required for implementation; these studies will consider ownership, economics, and engineering. Toronto Region Conservation, 2010 9-46 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Toronto Golf Club Weir (ECLOW006) The weir at the Toronto Golf Club is a barrier to the passage of lake-based species, except for salmonids and suckers in high water (see Figure 9-31). In balance, this weir also effectively prevents the upward migration of aquatic invasive species such as sea lamprey and round goby. The weir was originally constructed to allow for water withdrawals for golf course irrigation purposes. A number of years ago, the Toronto Golf Club switched to direct taking from Lake Ontario, thus no longer requiring the weir to be in place. In 2002, the weir was to have been mitigated however the planning and approvals process was delayed. As of 2009, the process was re-instated, however slightly new plans are being presented, thus the approvals process needs to start anew. One of the approval agencies is Fisheries and Oceans Canada (DFO) who has a specific mandate for sea lamprey control. Comments during the first project planning activity indicated that DFO was in support of the weir being mitigated as there is another barrier not far upstream (at the QEW) and the current state of the watershed is not conducive as sea lamprey habitat. Should the next weir be mitigated and rehabilitation efforts show measurable improvement in watershed health, there would be reason to consider sea lamprey control measures.
Q.E.W. Weirs The next two barriers upstream are 1) weirs 500m south of QEW bridge (ECLOW011) and 2) weir at Bloor Street (ECLOW 029) (see Figure 9-32 and Figure 9-33). Barrier ECLOW011 is part of the infrastructure for Water Survey Canada’s (WSC) water monitoring sites and supports a flow gauge. Both weirs may be protecting buried infrastructure which would likely prevent a simple removal. Also, structural removal at the flow gauge may alter years of collected background data; options for mitigation (not removal) are recommended for these weirs.
Britannia Road The fourth barrier identified is the weir at Britannia Rd (ECLOW039) (Figure 9-34). This barrier appears to be made of sheet metal and a wide variety of materials piled along its margin, including very large boulders. The purpose of this structure is unknown, but it may be tied to the Britannia Road crossing and directing flow.
Queen Street There are 4 remaining barriers to the headwaters. The first of these is located south-west of the intersection of Centre Street and Queen Street in Brampton, approximately 500 m south of Queen Street (MEE023) (Figure 9-35). Mitigation of this barrier could promote connectivity of approximately 19 km of upstream habitat effectively connecting the Lower Etobicoke Creek to the headwaters.
Beaver Dams The remaining 3 barriers are beaver dams (MEE033), (MEE059), (MEE060) shown in Figure 9-36. These natural barriers are found in the downstream reaches of the headwaters. As these structures are part of the natural ecosystem, they are generally left for river processes to remove them. However, in some cases, removal of beaver dams is something advocated for flooding issues and stream restoration. The management options will be slightly different if the beaver dams are active versus abandoned.
Toronto Region Conservation, 2010 9-47 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Figure 9-31: Weir at Toronto Golf Club Bridge (ECLOW006)
Figure 9-32: Weir 500m South of Q.E.W. Figure 9-33: Weir at Bloor Street West of Dixie (ECLOW011) Mill Road (ECLOW029)
Figure 9-34: Weir at Britannia Road and East Road (ECLOW039)
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Figure 9-35: Weir South of Queen Street West of Centre Street (MEE023)
Figure 9-36: Natural Barriers Weybridge Park (MEE033), Near Valleywood Development (MEE059), North of Mayfield between Hurontario and Kennedy (MEE060)
9.6.2 Category B – Extending Existing Natural Habitat A total of three barriers were identified for Category B Priority Management. The barriers are in Spring Creek - Bramalea West Tributary (SPBRWE009 and SPBRWE012) and Spring Creek Headwater Tributary (SPHL014) (Table 9-18 and Figure 9-37). Non-jumping species can not pass any of the three barriers (under low flow) and only one can be passed by jumping species. These two tributaries have significant portions of natural stream bed and good riparian vegetative cover.
Mitigating the two identified barriers In Spring Creek - Bramalea West Tributary would achieve a total of 2.5 km of reconnected, natural habitat. The third barrier, in Spring Creek Headwater Tributary, is a perched culvert. Mitigating this barrier would reconnect wetland habitat currently fragmented at Mayfield Road and Highway 410.
Table 9-18: Etobicoke Creek Priority Barriers for Management Category B Instream Structure and Location Passage Weir north-west of Queen Street and Hillside Dr. (SPBRWE 009) No Passage Weir north-west of Queen Street and Hillside Dr. (SPBRWE012) Jumping Species Only Perched culvert at Mayfield Road west of Heart Lake Road (SPHL014) No Passage
Toronto Region Conservation, 2010 9-49 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Figure 9-37: Priority Category B – Extending Existing Natural Habitat- Etobicoke Creek Watershed *
*Management recommendations are based on ecological benefit only. Approvals and Permits may be required under other existing legislation. Feasibility studies may also be required for implementation; these studies will consider ownership, economics, and engineering. Toronto Region Conservation, 2010 9-50 Etobicoke and Mimico Creeks Watersheds Technical Update Report
9.6.3 Category C – Stewardship Twelve potential stewardship projects are identified for Category C Priority Management and highlighted in Table 9-19 and shown in Figure 9-38. Examples of targeted, small scale structures are illustrated in Figure 9-39 (SPHL009), Figure 9-40 (ECLE031).
Table 9-19: Management Considerations for Priority Category C – Stewardship Opportunities
Management Considerations for Priority Category C - Stewardship
ECRC016 1-2 people - rock removal ECRC025 3-5 people – removal of 6 large flat stones ECRC030 1-2 people – monitoring - possible coy and carp in pond ECle009 Investigate stewardship opportunity – 3-5 people - rock removal ECle012 Investigate stewardship opportunity - 3-5 people – rock removal. (Large rocks small drop but requires restructuring, v notch) ECle020 Investigate stewardship opportunity - 1-2 people – rock removal (5 medium sized rocks – winch) ECle024 1-2 persons, rock removal ECle031 1-2 people, rock removal ECle037 2-4 people, removal of eroded weir –(permit required) SPBRAV028 3-5 people, education/planting opportunity SPHL009 1-2 people, removal of old sediment fence,
MELDCE002 1-2 people, stream cleanup- lumber in stream
Toronto Region Conservation, 2010 9-51 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Figure 9-38: Priority Category C – Stewardship Projects – Etobicoke Creek Watershed
*Management recommendations are based on ecological benefit only. Approvals and Permits may be required under other existing legislation. Feasibility studies may also be required for implementation; these studies will consider ownership, economics, and engineering. Toronto Region Conservation, 2010 9-52 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Figure 9-39: Rock obstruction north-east of Figure 9-40: Old sediment fence north-east of East Gate Parkway and Tomken Road Bovaird Road and 410. (SPHL009) (ECLE031)
Toronto Region Conservation, 2010 9-53 Etobicoke and Mimico Creeks Watersheds Technical Update Report
9.7 MANAGEMENT RECOMMENDATIONS - MIMICO CREEK PRIORITY BARRIERS 9.7.1 Category A – Lake to Headwaters With selecting the route from Lake Ontario and up through the main branch to the start of headwaters of the East Branch of Mimico Creek, a total of 12 barriers were identified as Category A Priority Management (Table 9-20 and Figure 9-41). All of these barriers are within the main branch, prevent passage of non-jumping species and of these, 3 prevent movement of jumping species. Mitigation of all 12 barriers would connect approximately 24.5 km of watercourse. Mimico Creek’s IBI ratings are poor at all sampling areas except at the mouth of the river (reflecting lake biodiversity) thus did not provide specific direction as to which headwater tributary to select. What did drive the decision to choose the East Branch was the recent restoration work that has re-naturalized almost 2 km of stream north of Airport Rd and Highway 407 and this will be discussed as part of Category B barriers. The following section provides details for Category A barriers.
Table 9-20: Mimico Creek Priority Barriers for Management Category A
Instream Structure and Location Species Passage 1. Weir south of Q.E.W (MC005) No Passage 2. Weir north of Q.E.W (MC007) No Passage 3. Weir south-west of Berry Rd. & Park Lawn (MC011) Jumping Species Only 4. Weir north-west of Berry Rd. & Park Lawn (MC013) Jumping Species Only 5. Weir at Meadowcrest Rd. & Royal York Rd. (MC016) Jumping Species Only 6. Weir at Meadowcrest Rd. & Royal York Rd. (MC017) Jumping Species Only 7. Weir south-west of Meadowvale Rd. & Royal York Rd. (MC020) Jumping Species Only 8. Weir south-west of Meadowvale Rd. & Royal York Rd. (MC021) Jumping Species Only 9. Weir north-west of Bloor St. & Mountgomery Rd. (MC024) Jumping Species Only 10. Weir south-east of Islington Ave. & Dundas St. (MC029) Jumping Species Only 11. Weir north-west of Hwy 401 & Hwy 27(MC055) No Passage 12. Road Crossing north-west of Zahavy Way & Goreway Dr. (MC083) Jumping Species Only
Toronto Region Conservation, 2010 9-54 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Figure 9-41: Priority Category A – Lake to Headwaters – Mimico Creek Watershed
*Management recommendations are based on ecological benefit only. Approvals and Permits may be required under other existing legislation. Feasibility studies may also be required for implementation; these studies will consider ownership, economics, and engineering. Toronto Region Conservation, 2010 9-55 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Weirs at Q.E.W. The first two barriers are weirs located upstream and downstream of the QEW bridge (see Figure 9-42 and Figure 9-43). These weirs are barriers to the passage of lake-based species during low flow conditions. Migratory species appear to be able to pass during high flows. In balance, these weirs also effectively prevent the upward migration of aquatic invasive species such as sea lamprey and round goby. The City of Toronto and TRCA are currently discussing management considerations for the first weir. Management of the second weir would be necessary to have appreciable gains to the aquatic system (i.e., more than just a few hundred metres).
Weirs throughout Berry Rd Park, Meadowcrest Road, and, Meadovale Drive Upstream of the Q.E.W weirs there are a series of structures created to slow flow and protect infrastructure but also allow for jumping species passage. The first two structures upstream of the Q.E.W weirs are two rocky weirs in the Berry Road Park area (Figure 9-44 and Figure 9-45). Upstream, near Meadowcrest road, two weirs appear to be created to ensure infrastructure protection (Figure 9-46 and Figure 9-47). Near Meadowvale road a series of three weirs occur. The first two are rocky weirs similar to the Berry Road Park weirs (Figure 9-48 and Figure 9-49). The third structure is part of Water Survey Canada’s (WSC) water monitoring site and supports a flow gauge (Figure 9-50). The next upstream weir is at Dundas Street weir and is also a rocky weir (Figure 9-51).
Weir at Skyway Drive This is the last weir in the main branch and it is a barrier to non-jumping and jumping species (Figure 9-52).
Zahavy Way Ramp
The remaining structure is a ramp located at the northern end of Zahavy Way, located upstream of the Highway 409 and 427 junction (Figure 9-53). This structure likely prevents the passage of non-jumping species due to sheet flow.
Figure 9-42: Weir at Q.E.W. (MC005) Figure 9-43: Weir at Q.E.W. (MC007)
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Figure 9-44: Weir 500m south of Berry Figure 9-45: Weir 100 m north of Berry Road (MC011) Road (MC013)
Figure 9-46: Weir 10m south of Figure 9-47: Weir 10m north of Meadowcrest Road (MC016) Meadowcrest Road (MC017)
Figure 9-48: Weir 80m south of Figure 9-49: Weir 90m south of Meadowvale Drive(MC020) Meadowvale Drive (MC021)
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Figure 9-50: Weir 240m north of Figure 9-51: Weir 70m downstream of Meadowvale Drive (MC024) WSC Dundas Street (MC029)
Figure 9-52: Weir 260m north-west of Figure 9-53: Ramp at upstream end of Skyway Ave and Highway 27 (MC055) Zahavy Way Rd Crossing (MC083)
9.7.2 Category B – Extending Existing Natural Habitat A total of three barriers were identified for Category B Priority Management (see Table 9-21 and Figure 9-54). All three barriers are within the headwaters of the Mimico Creek East Branch and their mitigation would reconnect existing natural habitat to the upstream reach that is being restored through the Upper Mimico Aquatic Habitat Implementation Project (see Figure 9-55, Figure 9-56 and Figure 9-57. Should all the barriers in Category A and Category B be mitigated, there would be passage for all species from Lake Ontario to the eastern headwaters.
Table 9-21: Mimico Creek Priority Barriers for Management Category B Instream Structure and Location Species Passage Railway Crossing north-east of Goreway Drive No Passage Weir northwest of Highway 407 and Goreway Drive No Passage Weir south of Intermodal Drive No Passage
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Figure 9-54: Priority Category B – Extending Existing Natural Habitats – Mimico Creek Watershed
*Management recommendations are based on ecological benefit only. Approvals and Permits may be required under other existing legislation. Feasibility studies may also be required for implementation; these studies will consider ownership, economics, and engineering. Toronto Region Conservation, 2010 9-59 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Figure 9-55: Railway Crossing 300m north- Figure 9-56: Weir 100m south of Intermodal east of Goreway Drive and Brandon Gate Drive (MCE050) Drive (MCE011)
Figure 9-57: Weir 250m north-west Highway 407 and Goreway Drive (MCE049)
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9.7.3 Category C – Stewardship Stewardship opportunities in Mimico Creek involve local garbage clean-up and have been highlighted in four main headwater areas (see Table 9-22)). Further, the areas have been prioritized based on the amount of garbage noted during the barrier assessment and on proximity to Category A and Category B barriers.
Table 9-22: Mimico Creek Priority Barriers for Management Category C Location Garbage Barriers Priority 1 - Mimico Creek main to east branch near Derry Road and 1 Goreway Drive – MCW042 Priority 2 - Mimico Creek east branch south-west of Queen Street and 2 Airport Rd - MCE066as, MCE057as Priority 3 - Mimico Creek West Branch north-west of Derry Road and Airport 3 Road – MCW078, MCW079np, MCW090np Priority 4 - Mimico Creek West Branch north-west of Steeles Ave and Airport 4 Road
Thus, Priority Area 1 is located upstream of a Category A barrier, and it is at the junction of the main, west and east Figure 9-58: Priority 1 Area (MCW042) branches (see Figure 9-58). Rehabilitation of this area will improve habitat connectivity between all the branches and achieve more system level benefit. Priority Area 2 is located directly upstream of the Upper Mimico Creek Aquatic Habitat Implementation project bringing added value to the naturalization of this reach. The remaining Priority Areas (3 and 4) are further away from identified rehabilitation projects but are still good choices for stewardship due to the large amount of garbage currently impacting the site (see Figure 9-59).
Toronto Region Conservation, 2010 9-61 Etobicoke and Mimico Creeks Watersheds Technical Update Report
Figure 9-59: Priority Category C – Stewardship Projects – Mimico Creek Watershed
*Management recommendations are based on ecological benefit only. Approvals and Permits may be required under other existing legislation. Feasibility studies may also be required for implementation; these studies will consider ownership, economics, and engineering. Toronto Region Conservation, 2010 9-62 Etobicoke and Mimico Creeks Watersheds Technical Update Report
9.8 OVERALL SUMMARY OF MANAGEMENT CONSIDERATIONS FOR ETOBICOKE AND MIMICO CREEKS WATERSHEDS The underlying guidance used to select barrier management priorities has been to reconnect good or productive (higher abundance and diversity) habitat to like habitat. By prioritizing areas where natural stream bed and good riparian vegetative cover exist, and that may overlap with groundwater discharge zones and/or stream restoration projects, greater opportunity for successful reproduction, biodiversity and general fish survival is created sooner than later.
By emphasizing the connection of the lower reaches of Etobicoke Creek through the Etobicoke Creek West Branch to the headwaters, fish could utilize 50 km of watercourse that would flow through existing “fair” and “good” habitat (Category A). Several areas along this route have been identified as terrestrial restoration priorities, thus further enhancing the benefits of just improving fish passage. Multiple benefits are also achieved in the upper reaches of Spring Creek by looking to enhance the wetland from a terrestrial perspective and reconnect the wetland to the stream for fish (Category B). Some of the best natural habitat is in the Bramalea West Tributary also in Spring Creek subwatershed and can be connected by mitigating 2 barriers (Category B).
Reconnecting the Lake to the Mimico Creek headwaters would require a lot more effort as compared to the Etobicoke Creek due to the numerous barriers existing through the main stem, the only route up to the headwaters (Category A). The most immediate gains would likely be measurable (diversity and abundance) in the lowest reaches by mitigating the first few barriers and allow (native) species from the lake to become better connected with the watershed. The opportunities for multiple benefits in the headwaters centre on restoration efforts that have greatly improved habitat conditions in the East Mimico Creek headwaters (Category B).
Stewardship initiatives have also been identified in both watersheds (Category C) to enhance benefits of larger projects if done in close proximity, but also to gain community support for a cleaner, healthier urban stream system at the local scale.
Although this report focused on barrier management, overall aquatic ecosystem management action is critically tied to restoring the natural hydrology of both watersheds, to the extent possible. With the priority on better stormwater management and in addition to barrier mitigation, there should also be the incorporation of ecological buffer zones, riparian plantings, and the minimizing of impervious land cover described in the Turning over a new leaf: The Etobicoke and Mimico Creeks Watersheds Report Card 2006 (TRCA, 2006).
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9.9 REFERENCES Allendorf, F.W., N. Ryman, and F.M. Utter. 1987. Genetics and fishery management: past, present, and future. Pages 1–19 in N. Ryman and F.W. Utter, editors. Population Genetics and Fishery Management. University of Washington Press, Seattle.
Brooker, M.P. 1985. The Ecological Effects of Channelization. The Geographical Journal. 151:1.63-69.
Cummins, K.W. 1974. Structure and function of stream ecosystems. BioScience 24: 63 1-64 1.
Cummins, K.W. 1979. The natural stream ecosystems. pp. 7-24. In: J.W. Ward & J.A. Standford (eds). The Ecology of Regulated Streams. Plenum, New York.
Gibson, R.J., and G. Power. 1975. Selection by brook trout ( Salvelinus fontinalis ) and juvenile Atlantic salmon (Salmo salar) of shade related t o water depth. Fisheries Research Board or Canada 32: 1652-1656. Journal of the Fisheries Research Board of Canada 32:1652-1656.
Gosset, C., Rives, J., Labonne, J. 2006. Effect of habitat fragmentation on spawning migration of brown trout (Salmo trutta L.). Ecology of Freshwater Fish. 15. 247- 254.
Hanfling, B., Durka, W., Brandl R. 2004. Impact of habitat fragmentation on genetic population structure of roach, Rutilus rutilus, in a riparian ecosystem. Conservation Genetics. 5. 247-257.
Jenkins, R.A., Wade, W.R. and Pugh, E. 1984. Macroinvertebrate-habitat relationships in the River Teifi catchment and the significance to conservation. Freshwater Biology, 14, 23- 42.
Lakes and Rivers Improvement Act, 2007. Ontario Regulation 454/96. Lakes and Rivers Improvement Act.
Milner, N.J., Scullion, J., Carling, P.A., and Crisp, D.T. 1981. The effects of discharge on sediment dynamics and consequent effects on invertebrates and salmonids in upland rivers, Adv. Appl. Biol.,6,153-220.
Paul, M. J., & Meyer, J. L. 2001. Streams in the urban landscape. Annual Review of Ecology and Systematics 32. 333–365.
Poff, N.L., and Allan, J.D. 1995. Functional organization of stream fish assemblages in relation to hydrologic variability. Ecology, 76(2): 606-627. doi:10.2307/1941217.
Roy, A.H., Freeman, M.C., Wenger, S.J., Ensign W.E., Meyer, J.L. 2005. Investigating hydrologic alteration as a mechanism of fish assemblage shifts in urbanizing streams. Journal of North American Benthological Society. 24:3. 656-678.
Schueler, T.R. 1994. The importance of imperviousness. Watershed Protection Techniques 1(3):100–111. Schueler. T.R. and H.K. Holland. eds. 2000. The practice of watershed protection. Ellicott City, MD: Center for Watershed Protection.
Stuart, T.A. 1962. The leaping behaviour of salmon and trout at falls and obstructions. Freshwater and Salmon Research 28:1-46.
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Toronto and Region Conservation Authority (TRCA). 2006. Turning over a new leaf: The Etobicoke and Mimico Creeks Watersheds Report Card 2006 Wang, L., J. Lyons, P. Kanehl, R. Bannerman, E. Emmons. 2000. Watershed urbanization and changes in fish communities in southeastern Wisconsin streams. Journal of the American Water Resources Association 26: 1173-1189.
Walsh, C.J., Roy, A.H., Feminella, J.W., Cottingham, P.M., Groffman, P.M., and Morgan, R.P. 2005. The urban stream syndrome: current knowledge and the search for a cure. Journal of the North American Benthological Society 24. 706–723.
Walters, D.M., D.S. Leigh, M.C. Freeman, B.J. Freeman, and C.M. Pringle. 2003. Geomorphology and fish assemblages in a Piedmont river basin, U.S.A. Freshwater Biology 48:1950-1970.
Weaver, L.A., and G.C. Garman. 1994. Urbanization of a watershed and historical changes in a stream fish assemblage. Transactions of the American Fisheries Society 123:162-172.
Wofford, J.E., Gresswell, R.E., Banks, M.A. 2005. Influence of barriers to movement on within- watershed genetic variation of coastal cutthroat trout. Ecological Applications.15:2.628- 637.
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9.10 APPENDIX 9-A – ASSESSMENT FORM FOR BARRIER SURVEY
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