appendix g fluvial geomorphologic assessment · aqualogic. 3 . at the time of field work the...

APPENDIX G

Fluvial Geomorphologic Assessment

Fluvial Geomorphology Assessment East Oshawa Creek & Tributary, Harmony Creek Tributaries Conlin Road East Class EA City of Oshawa

Submitted to: Amec Foster Wheeler 3215 North Service Rd. Burlington, ON L7R 3Y2 March 17, 2014 / UPDATED December 22, 2014

AquaLogic Consulting • 9 Ellen St. #1, Mississauga, ON L5M 1R8 • 905.819.9076 • [email protected]

Fluvial Geomorphology Assessment East Oshawa Creek & Tributary, Harmony Creek Tributaries Conlin Road East Class EA City of Oshawa East Oshawa Creek, an East Oshawa Creek Tributary, and two Harmony Creek Tributaries have been investigated based on fluvial geomorphic requirements for crossings of Conlin Road East in the City of Oshawa. Characterization reviews followed by analysis of meander belt limits, 100yr erosion limits, scour protection and fish passage, has been undertaken with regard to crossing recommendations. Watershed and Watercourse Characterization East Oshawa Creek At the study site location East Oshawa Creek is a 4th order watercourse with an upstream drainage area of approximately 38.7km2. The site falls within the South Slope physiographic region. Upstream catchment land use is predominantly rural with valley and tableland woodlots, small areas of aggregate extraction, golf course, hydro corridor, and some urbanizing residential low density development. The future Highway 407 extension also traverses the catchment. The existing Conlin Road crossing falls within an approximate 150m wide valley that varies up to 10m deep. The creek is occasionally confined against the toe of valley slope in upstream and downstream areas from the crossing, with localized partial entrenchment through the flood plain. Bankfull width varies from approximately 5-9m and the creek meanders with a well defined sequence of riffles, runs and pools, with well defined deposits of gravel to small boulder material seen in riffle bedforms, and sand to gravel seen in point bar formations. Low flow definition is well defined within the bankfull channel with a mix of vegetation types from dense groundcover to mature trees along the low flow margins. Erosion scars are seen in outside bends and large woody debris deposits occur at several locations. The existing crossing opening is a 12.2m open span bridge with concrete wall abutments. Rip-rap erosion protection is installed discontinuously under the crossing and it appears some of the placement has been dislodged and deposited within the creek downstream. Exposed filter cloth is also seen on the bed of the creek below the crossing. Small armourstone and boulder bank treatment appears below the crossing and some of this material has also been dislodged. A storm sewer outfall is confluent with the creek below the crossing on the west bank.

Fluvial Geomorphology Assessment Conlin Road East Class EA

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East Oshawa Creek Tributary The first tributary east of the main branch of Oshawa Creek is a 2nd order watercourse with an upstream drainage area of approximately 2.4km2. Plowed through agricultural fields may obscure extra headwater tributaries that would render the watercourse 3rd order. The site falls within the South Slope physiographic region. Upstream catchment land use is predominantly rural with the future Highway 407 extension traversing the upper catchment boundary. Upstream of Conlin Road the tributary falls within a valley up to 50m wide and 5-10m deep. Bankfull width varies from approximately 3-4m. Upstream riparian conditions are dominated by dense groundcover with limited tree and shrub presence. The tributary appears dynamically stable with good flood plain connection. Competent clay and silt cohesive soils are dominant with some sandy-silt, and occasional gravel and cobble deposits. Downstream of Conlin Road the tributary steepens and riparian swamp thicket conditions are dominant. Noticeable erosion patterns and bedform steps formed of gravel-cobble, organic debris jams, and root fan intrusions into the channel, are seen. The tributary becomes entrenched and erosion scars extend to the height of channel capacity. The existing crossing is a closed box culvert with a 3.6m width opening. Low flow connection is good at both ends of crossing but the bed is swept of natural materials rendering low flows wide and shallow to the box walls. A distinct scour pool exists on the downstream face of the culvert and rip-rap material is seen on the downstream bed in a discontinuous pattern. Harmony Creek West Tributary The westerly tributary of Harmony Creek is a 1st order watercourse with an upstream drainage area of approximately 2.0km2. Plowed through agricultural fields may obscure extra headwater tributaries that would render the watercourse 2nd order. The site falls within the South Slope physiographic region. Upstream catchment land use is predominantly rural with the future Highway 407 extension traversing the upper catchment boundary. At the time of field work in 2013, upstream of Conlin Road the tributary flowed as a roadside ditch with a gabion retaining wall along the road edge. The tributary swings perpendicular to the north into a flat flood plain dominated by dense groundcover with a forest thicket on the east bank. Bankfull width varies from 2.5-3.5m. On the downstream side of Conlin Road the tributary flows through a similar flood plain with dense grass and groundcover biotechnical control and slightly incised channel conditions.


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At the time of field work the crossing was a 2.4m wide concrete culvert with some rip-rap protection. At the time of reporting, the crossing has been replaced by a longer open bottom culvert 8m wide, and the tributary has been locally realigned in a new natural channel design to meet the new crossing. Harmony Creek East Tributary The easterly tributary of Harmony Creek is a 2nd order watercourse with an upstream drainage area of approximately 4.3km2. Plowed through agricultural fields may obscure extra headwater tributaries that would render the watercourse 3rd order. The site falls within the South Slope physiographic region. Upstream catchment land use is predominantly rural, with small woodlots, hydro corridor, and the future Highway 407 extension traversing the middle of the catchment. Upstream of Conlin Road the tributary falls within a small moderately entrenched valley 10-20m wide between agricultural fields. Bankfull width varies from approximately 3-5m. Upstream riparian conditions are a diverse mix of dense groundcover, with shrub and tree stands. The tributary appears dynamically stable despite being entrenched. Cohesive soils are dominant with some sandy-silt, and occasional gravel and cobble deposits. Downstream of Conlin Road the tributary flows through a recently constructed (2012-13) meandering natural channel design consisting of defined riffle and pool sequencing. Riffles are constructed of riverstone cobble placed at relatively steep gradient. Pools appear to be cut in native material and riparian conditions are developing as seeded groundcover with only occasional tree plantings offset from the channel. The crossing structure is an open bottom culvert 7.3m wide, constructed at the same recent time as downstream channel work. The crossing is completely lined wall to wall with riverstone gravel-cobble and a downstream apron of cobble to small boulder material extends within the channel for several metres. Rapid Assessment Protocols Three rapid assessment protocols were undertaken for the upstream and downstream reaches within close proximity to each crossing. Field observations were used to score relative geomorphic and environmental attributes. Rapid Geomorphic Assessment (RGA) was used to rate channel stability and infrastructure impact. Rapid Habitat Assessment (RHA) was used to define in-stream and riparian habitat. Rapid Stream Assessment Technique (RSAT) was used to test broad indicators of channel stability, aquatic habitat, and water quality. A weighted score out of 100 was transposed from the results of each protocol and a combined average score was determined from the three tests. Four qualifying ranges of poor, fair, good, and optimal are maintained in the RHA and RSAT protocols, between the original scoring and the weighted scoring out of 100, while the three


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original ranges in RGA scoring are reflected as poor, fair, and good. The combined average score is qualified by poor to optimal ranges designed as a best fit of the individual protocol ranges. The detailed results are appended and included with each are photographs of typical reach conditions. Scoring results are summarized in Table 1. Table1: Rapid Assessment Protocol Summary Scoring Results

RGA RHA RSAT Combined

East Oshawa Creek u/s 74.6 77.5 82.0 78.0 East Oshawa Creek d/s 72.1 81.0 86.0 79.7

East Oshawa Creek Tributary u/s 87.9 71.0 88.0 82.3 East Oshawa Creek Tributary d/s 65.7 71.0 76.0 70.9

Harmony Creek Tributary West u/s 88.9 68.5 84.0 80.5 Harmony Creek Tributary West d/s 91.4 71.0 84.0 82.1

Harmony Creek Tributary East u/s 87.9 71.5 84.0 81.1 Harmony Creek Tributary East d/s 86.8 53.5 48.0 62.8

Meander Belt Analysis Historical review of meander amplitude and meander belt limits was done to screen for any adverse channel planform characteristics that could influence crossing sizing. While meander amplitude or meander belt limits are not normally used to size crossings, the review exercise is useful to identify expansive or contractive planform movement and down valley trend with regard to future potential erosion concerns. Overlay comparisons of scanned 1971 and 1987 grayscale contact print air photos were done with 2012 digital colour image coverage. This process has a certain margin of error attributable to any original photo distortion, enlargement distortion, and resolution blur. In this study case, fixed road layout and crossing references were used as match points. Reasonable accuracy was achieved with regard to photo orientation and scale. A digital centre line trace was made of each channel pattern for several hundred metres upstream and downstream of the crossing. Given the high density of vegetative encroachment in some areas of the smaller tributaries, there are several locations where a pattern was not clearly visible and a best estimate was made. The detailed results showing side by side historical planform comparisons and the overlay of all three time steps are appended for each of the four watercourses. East Oshawa Creek The East Oshawa Creek comparison shows generally similar planform patterns at each interval with some deviation in the order of approximately two to three channel widths upstream of Conlin Road but near coincident patterns downstream of Conlin Road with


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deviation of approximately one channel width on average. There is evidence of a former oxbow immediately upstream in the westerly flood plain but this feature has gradually lost definition (filled in) overtime. Based on field inspection it does not represent an unstable split or relief flow alignment that is impacting the crossing. There is no evidence of a system wide expansive amplitude or meander belt pattern and likewise there is no evidence of reach or meander based down valley translation of aggressive erosion patterns towards the crossing. Based on this summary there is no need to make recommendations for meander pattern related requirements for crossing sizing of the main branch of East Oshawa Creek. The meander amplitude limits for East Oshawa Creek are approximately 25m +/-. The meander belt limits for East Oshawa Creek are approximately 80m +/-. East Oshawa Creek Tributary The East Oshawa Creek Tributary comparison shows a mix of broadly similar patterns and localized areas of distinct differences. The Conlin Road crossing was upgraded (lengthened) between the 1971 and 1987 intervals and it appears the tributary may have been realigned for approximately 40m on the upstream side to meet the longer crossing extension. The upstream planform patterns are otherwise nearly coincident for at least a couple hundred metres. Downstream of the crossing the patterns are generally coincident to Wilson Road except for a westerly deviation in the 1971 pattern over approximately 30m at a distance of about 40m from the crossing. It does appear that the easterly movement in the channel seen in the 1987 and 2012 patterns is due to meander erosion but is more likely due to localized avulsion to a relief channel formation, change from debris deflection, or resulting from beaver activity. There is no evidence of a system wide expansive amplitude or meander belt pattern and likewise there is no evidence of reach or meander based down valley translation of aggressive erosion patterns towards the crossing. Based on this summary there is no need to make recommendations for meander pattern related requirements for crossing sizing of the East Oshawa Creek Tributary. The meander amplitude limits for the East Oshawa Creek Tributary are approximately 10m +/-. The meander belt limits for the East Oshawa Creek Tributary are approximately 25m +/-. Harmony Creek West Tributary The Harmony Creek West Tributary comparison shows broadly similar planform patterns with some localized change near the crossing. Clearly the tributary has been historically straightened in upstream and downstream areas and the 1987 and 2012 patterns show the watercourse developing some natural meander sequencing on the downstream side of the crossing and minor adjustment on the upstream side where the channel turns to enter the roadside gabion wall alignment noted in the characterization discussion. Since the 2012 air photo, as already noted, the crossing has been rebuilt with a new wider and longer structure and the channel realigned on the upstream side to meet the existing creek approximately 20m north of the road. It is difficult to predict any future changes that might result from this recent construction but it is suffice to identify that further upstream there is no evidence of a


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system wide expansive amplitude or meander belt pattern and likewise there is no evidence of reach or meander based down valley translation of aggressive erosion patterns towards the crossing. Based on this summary there is no need to make recommendations for meander pattern related requirements for crossing sizing of the Harmony Creek West Tributary. The meander amplitude limits for the Harmony Creek West Tributary area approximately 8m +/-. The meander belt limits for the Harmony Creek West Tributary are approximately 20m +/-. Harmony Creek East Tributary The Harmony Creek East Tributary comparison shows a mix of broadly similar patterns and localized areas of distinct differences. Upstream of the crossing the channel appears to be meandering within the confined and entrenched valley over the equivalent of three to four active channel widths. There is evidence of the meander belt axis shifting slightly over time with the meander pattern but no clear evidence of belt expansion. Downstream of the crossing the former natural pattern of 1971 was replaced with straightening by 1987 that has not deviated by the 2012 air photo. As noted in the characterization section however, the tributary has more recently been realigned again in a meandering natural channel design downstream of the crossing. There is no evidence of a system wide expansive amplitude or meander belt pattern and likewise there is no evidence of reach or meander based down valley translation of aggressive erosion patterns towards the crossing. Based on this summary there is no need to make recommendations for meander pattern related requirements for crossing sizing of the Harmony Creek East Tributary. The meander amplitude limits for the Harmony Creek East Tributary are approximately 15m +/-. The meander belt limits for the Harmony Creek East Tributary are approximately 30m +/-. 100yr Erosion Limits The results of meander belt analysis identified a lack of need to consider opening widths in terms of planform patterning. The shift in focus therefore turns to localized channel stability using standard criteria from existing guidelines. From a geomorphic perspective opening width and protection requirements are based on a combination of bankfull channel width plus appropriate 100yr erosion setbacks integrated with scour treatment requirements. Scour treatments are shaped to define bankfull channel geometry and are enhanced with appropriate substrate for fish habitat and barrier free fish passage is tested. Each of the crossing locations are targeted for channel stability based on the 100yr (minimum) scour protection requirements of MTO Guidelines WC-1/WC-3 for arterial/collector roads (MTO 2008). A Provincial Guideline criterion for 100yr erosion limits (MNR 2002) in turn applies for stable channel definition given the presence or retrofitted installation of appropriate scour treatments. Five field measurements were made of bankfull channel width in proximity to each crossing and the appropriate stable channel setback was determined based on underlying cohesive soil conditions. The setback for East Oshawa


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Creek is 2m and for each of the smaller watercourses is 1m based on the over and under 5m bankfull widths respectively for each watercourse. Appended is a summary of bankfull measurements combined with the recommended setbacks and comparison to existing conditions of crossing width. Based on the results of analysis, the East Oshawa Creek Tributary existing crossing is deemed to be undersized. Table 2 summarizes the recommended opening widths for each crossing. Table 2: Recommended Opening Width Summary

existing recommended existing

bankfull width opening width opening width

(m) (m) (m) East Oshawa Creek 7.4 11.4 12.2

East Oshawa Creek Tributary 3.5 5.5 3.6 Harmony Creek Tributary West 2.6 4.6 8.0 Harmony Creek Tributary East 4.5 6.5 7.3

As presented, the recommended opening widths are based on the assumption that each location will be fully protected against scour per the treatment sizing requirements of MTO guidelines, as described in the subsequent section. In this regard, the hydrology and hydraulics used for scour treatment sizing that are applied at the time of this analysis, may not be guaranteed to fully account for any or all future changes in upstream conditions. Opening sizing may be affected by unforeseen circumstances due to upstream changes. The results of scour treatment analysis presented below indicate that East Oshawa Creek and both of the Harmony Creek Tributaries may not be fully protected to the 100yr criterion, and the East Oshawa Creek Tributary is protected by default as a concrete box culvert. The recommended opening widths for East Oshawa Creek and both of the Harmony Creek Tributaries are therefore unsupported until the full standard of scour protection is implemented. Upon future potential replacement of the East Oshawa Creek Tributary crossing, detailed design will need to support the full standard of scour protection requirements. 100yr Scour Treatment Analysis Scour treatment design was undertaken using 100yr and Regional event velocity from proposed conditions HECRAS modelling. Velocities are updated to the point of revised reporting based on HECRAS provided by AMEC (December 8) that includes considerations of recent technical reports for the study area as identified in City of Oshawa comments dated May 28, 2014. Velocities are summarized in HECRAS excerpts shown in Table 3.


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Table 3: HECRAS Velocities for Scour Analysis EAST OSHAWA CREEK

Q Channel Vel Chnl Reach River Sta Profile (m3/s) (m/s) Reach-2.5 22.5 BR U ‘100Yr-Cont.’ 75.65 2.59 Reach-2.5 22.5 BR D ‘100Yr-Cont.’ 75.65 2.64

EAST OSHAWA CREEK TRIB Q Culv Group Culv Vel US Culv Vel DS

Reach River Sta Profile (m3/s) (m/s) (m/s) Reach-1 7.2435 Culvert #1 ‘100Yr-Cont.’ 9.16 2.91 2.12

HARMONY CREEK WEST TRIB Q Culv Group Culv Vel US Culv Vel DS

Reach River Sta Profile (m3/s) (m/s) (m/s) Reach-1 307762 Culvert #1 ‘Greck Regulatory’ 22.42 1.89 1.89

HARMONY CREEK EAST TRIB Q Culv Group Culv Vel US Culv Vel DS

Reach River Sta Profile (m3/s) (m/s) (m/s) Reach-1 38105 Box5 ‘Greck Regulatory’ 30.41 2.52 2.52

Conlin Road is an ‘urban arterial’ route which requires a 1.3 factor of safety applied to scour treatment analysis per MTO Highway Drainage Design Standards (MTO 2008). Velocities were used as input for a treatment sizing model and the FS=1.3 was applied. It should be noted that Regional event velocities were used in lieu of the minimum criterion of the 100yr event on the Harmony Creek tributaries because the HECRAS model did not contain the 100yr event, and because these velocities are nonetheless conservatively high while being comparatively lower than the East Oshawa Creek and East Oshawa Creek Tributary. Detailed results of modeling are appended followed by a summary sheet. Based on the results, angular stone treatment gradations can provide moderately smaller sizing than riverstone. The Harmony Creek West Crossing can be partially treated by a standard sizing gradation for OPSS R-50 rip-rap up to the D50 with an additional custom gradation of 400mm stone to achieve full protection to the D100. All other crossings would require custom gradations at higher ranges than OPSS. Typical installation of stone treatments in open bottom crossings should have overbanks in-filled with soil to a balance line 10cm above the installed stone depth to match upstream and downstream daylight grades and to mimic bare cohesive native soil that would exist under shaded crossing conditions. A 20cm depth would be recommended for East Oshawa Creek because of moderate sunlight penetration that may be conducive to some vegetation establishment in the deeper overbank material. The fill cap should be compacted in place to a level natural surface that allows movement of small mammals along the created overbank terrace. Similarly in the bankfull channel, native creek bed substrate material should be used to void fill the scour treatment and define the constructed bankfull and low flow


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geometry to mimic physical stream bed conditions for fish habitat and barrier free passage per the intent of MTO WC-12 guidelines (MTO 2008) and MTO fish habitat mitigation (MTO 2009). Existing conditions under the East Oshawa Creek crossing include a mix of native soils and small amounts of formerly placed rip-rap. The channel is not explicitly unstable but long term scour protection does not currently exist. Consideration should be given to enhance long term protection by a retrofit to the treatment sizing presented in this report. Given that the East Oshawa Creek Tributary is a full box culvert, the continuous concrete lining would supersede stone treatment under current conditions. No recommendation would be made to retrofit this location unless the crossing were to be replaced (new sizing and profile will most likely result in new hydraulics and thus requirements for updated scour analysis). Design plan review of the recently constructed Harmony Creek Tributary West shows bankfull channel stone treatment sizing at slightly less than the recommended long term treatment and no protection between bankfull limits and crossing walls. Site review of the recently constructed Harmony Creek Tributary East crossing observed stone sizes smaller than the recommended long term treatment, however it is unknown if larger material exists under the observed surface. Consideration could be given to retrofit each of the Harmony Creek Tributary crossings to meet full scour protection, recognizing however the difficulty in now accessing the bed of the creek and the overbank terrace under these recently upgraded crossings. The hydrology and hydraulics used for scour treatment sizing that are applied at the time of this analysis, may not be guaranteed to fully account for any or all future changes in upstream conditions. Treatment sizing may be affected by unforeseen circumstances due to upstream changes. Fish Passage Analysis Fish passage analysis was undertaken in summary fashion only. Velocity nomographs or other calculations can be used to assess the size of fish capable of moving upstream against specific nose velocities. Bankfull to 2yr event velocities are typically used for very conservative analysis. The East Oshawa Creek main branch is a large existing opening with no identified significant channel slope constraints. Upstream fish migration past this structure is well known at times of seasonal peak flows, i.e. the spring freshet or fall storms, and there are no passage issues deemed to be occurring at this crossing under existing or future unchanged conditions. Should a retrofit of scour protection be implemented at this crossing,


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it should be installed at the same channel slope and in matching bankfull and low flow geometry that blends with upstream and downstream daylight connections. Fish passage issues may be currently occurring at the existing East Oshawa Creek Tributary crossing due to the confined box culvert influence on velocity. A retrofit of existing conditions, without culvert removal, is likely unfeasible to reduce velocity. This would involve adding treatments for additional roughness within the box, and this would influence capacity and conveyance of peak flows. If a replacement of this crossing is considered, an appropriate analysis of fish passage velocities should be done in concert with the geometry of the new design. Added consideration should also be given to how the low flow feature will blend with the steep downstream connection. Given that both of the Harmony Creek tributaries are ‘new’ crossing replacements within the last 1-2 years, analysis of fish passage is assumed to be implicit in the relevant reporting or agency reviews. Should retrofits of the treatments within either of these crossings be considered in the future, it would be appropriate to confirm channel geometry within and blending upstream and downstream from the crossings and appropriate analysis of fish passage velocities could be done. Conclusions East Oshawa Creek, an East Oshawa Creek Tributary, and two Harmony Creek Tributaries have been investigated based on fluvial geomorphic requirements for crossings of Conlin Road East in the City of Oshawa. Analysis of meander belt limits, 100yr erosion limits, scour protection, and fish passage, has been undertaken. Recommendations for sizing and treatments within the crossings respecting channel stability and fish habitat function have been made. Crossings could be monitored for future changes, designed or redesigned to meet recommended standards presented in this report, and could be retrofitted to meet these standards. Implementation would include upstream to downstream blending of bankfull and low flow channel geometry as defined within wall to wall scour protection treatments. Scour treatments would be enhanced by overbank void filling using native soils to facilitate wildlife terrace movement, and channel perimeter void filling using native creek bed sediments to provide physical fish habitat and barrier free natural channel performance. Prepared by,

Bill de Geus, B.Sc., CET, CPESC, EP AquaLogic Consulting


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References Chapman, L.J., and D.F. Putnam. 1984. The Physiography of Southern Ontario: Ontario Geological Survey, Special Volume 2. Chapman. L.J., and D.F. Putnam. 1984. Physiography of Southern Ontario: Ontario Geological Survey, Map P.2715. Scale 1:600,000. Ontario Ministry of Natural Resources (MNR), Water Resources Section. 2002. Technical Guide - River & Stream Systems: Erosion Hazard Limit. Ontario Ministry of Transportation (MTO). 2008. Highway Drainage Design Standards. Ontario Ministry of Transportation (MTO). 2009. Environmental Guide for Fish and Fish Habitat.

GEO-RAP v.1.2 Rapid Assessment Protocol Model

Project: Conlin Road East EAEast Oshawa Creek B. de Geus 03.12

Existing Conditions Upstream

1) Rapid Geomorphic Assessment (RGA)

Lobate bar Fallen/leaning trees/fence posts etc. 1Coarse material in riffles embedded 1 Occurrence of Large Organic Debris 1n Coarse material in riffles embedded 1 Occurrence of Large Organic Debris 1Siltation in pools 1 Exposed tree roots 1Medial bars 1 Basal scour on inside meander bendsAccretion on point bars 1 Basal scour on both sides of channel through rifflePoor longitudinal sorting of bed materials Gabion baskets/concrete walls etc. out flankedDeposition in the overbank zone Length of basal scour >50% through subject reach

n/7 = 0.57 Exposed length of previously buried pipe/cable etc.Exposed bridge footing(s) Fracture lines along top of bankExposed sanitary/storm sewer/pipeline etc. Exposed building foundationElevated stormsewer outfall(s) n/10 = 0.30Undermined gabion baskets/concrete aprons etc. Formation of chute(s)Scour pools d/s of culverts/stormsewer outlets Single thread channel to multiple channelCut face on bar forms Evolution of pool-riffle form to low bed relief formHead cutting due to knick point migration Cut-off channel(s) 1

Agg

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tion

Deg

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Wid

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Head cutting due to knick point migration Cut off channel(s) 1Terrace cut through older bar material Formation of island(s)Suspended armour layer visible in bank Thalweg alignment out of phase meander formChannel worn into undisturbed overburden/bedrock Bar forms poorly formed/reworked/removed

n/10 = 0.00 n/7 = 0.14STABILITY INDEX (SI) = (A + D + W + P) / 4 = 0.25

SI < 0.2 In Regime0.2 < SI < 0.4 Transitional

SI > 0.4 In Adjustment100 - (100*SI) = 74.6

2) Rapid Habitat Assessmemt (RHA)

D

Pla

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Riffle Run Channel Type Glide Pool Channel TypeOptimal Good Fair Poor Optimal Good Fair Poor

Epifaunal Substrate / Available Cover 14 20--16 15-11 10-6 5-0 Epifaunal Substrate / Available Cover 17 20--16 15-11 10-6 5-0Embeddedness 14 20--16 15-11 10-6 5-0 Pool Substrate Characterization 12 20--16 15-11 10-6 5-0

Velocity / Depth Regime 16 20--16 15-11 10-6 5-0 Pool Variability 6 20--16 15-11 10-6 5-0Sediment Deposition 10 20--16 15-11 10-6 5-0 Sediment Deposition 14 20--16 15-11 10-6 5-0Channel Flow Status 18 20--16 15-11 10-6 5-0 Channel Flow Status 6 20--16 15-11 10-6 5-0

Channel Alteration 17 20--16 15-11 10-6 5-0 Channel Alteration 15 20--16 15-11 10-6 5-0Frequency of Riffles 16 20--16 15-11 10-6 5-0 Channel Sinuosity 12 20--16 15-11 10-6 5-0Bank Stability u/s L 7 10-8 7-6 5-3 2-0 Bank Stability u/s L 10 10-8 7-6 5-3 2-0

u/s R 7 10-8 7-6 5-3 2-0 u/s R 10 10-8 7-6 5-3 2-0Vegetative Protection u/s L 8 10-8 7-6 5-3 2-0 Vegetative Protection 10 10-8 7-6 5-3 2-0

u/s R 8 10-8 7-6 5-3 2-0 u/s R 10 10-8 7-6 5-3 2-0Riparian Vegetation Zone Width u/s L 10 10-8 7-6 5-3 2-0 Riparian Vegetation Zone Width 10 10-8 7-6 5-3 2-0

u/s R 10 10-8 7-6 5-3 2-0 u/s R 10 10-8 7-6 5-3 2-0/200 155 /200 142/100 77.5 Optimal Good Fair Poor /100 71.0 Optimal Good Fair Poor

100-78 77-53 52-28 27-0 100-78 77-53 52-28 27-0

3) Rapid Stream Assessment Technique (RSAT) Combined Assessment

Optimal Good Fair PoorChannel Stability 8 11-9 8-6 5-3 2-0 Riffle Run Channel Type

Channel Scouring/Deposition 6 8-7 6-5 4-3 2-0Physical Instream Habitat 6 8 7 6 5 4 3 2 0 (RGA + RHA + RSAT) / 3 = 78 0 Optimal Good Fair PoorPhysical Instream Habitat 6 8-7 6-5 4-3 2-0 (RGA + RHA + RSAT) / 3 = 78.0 Optimal Good Fair Poor

Water Quality 7 8-7 6-5 4-3 2-0 100-80 80-56 55-30 29-0Riparian Habitat Conditions 6 7-6 5-4 3-2 1-0

Biological Indicators 8 8-7 6-5 4-3 2-0 Glide Pool Channel Type/50 41

/100 82.0 Optimal Good Fair Poor (RGA + RHA + RSAT) / 3 = 75.9 Optimal Good Fair Poor

100-83 82-59 58-31 30-0 100-80 80-56 55-30 29-0

▼ Looking downstream at crossing showing low flow alignment and overbank terrace under crossing on eastoverbank terrace under crossing on east

References

1) Ontario Ministry of Environment and Energy. 2003. Stormwater Management Planning and Design Manual. Appendix C.

2) USEPA. 2004. Wadeable Stream Assessment: Field Operations Manual. EPA841-B-04-004. U.S. Environmental Protection Agency, Office of Water and Office of Research and Development, Washington, DC.

3) Galli, J., 1996. Rapid stream assessment technique, field methods. Metropolitan Washington Council of Governments.

▲ Overview looking upstream from Conlin Rd. - mixed groundcover with some swamp thicket; valley wall contact


Project: Conlin Road East EAEast Oshawa Creek B. de Geus 03.12

Existing Conditions Downstream


Lobate bar Fallen/leaning trees/fence posts etc. 1Coarse material in riffles embedded 1 Occurrence of Large Organic Debris 1n Coarse material in riffles embedded 1 Occurrence of Large Organic Debris 1Siltation in pools 1 Exposed tree roots 1Medial bars 1 Basal scour on inside meander bendsAccretion on point bars 1 Basal scour on both sides of channel through rifflePoor longitudinal sorting of bed materials Gabion baskets/concrete walls etc. out flankedDeposition in the overbank zone Length of basal scour >50% through subject reach

n/7 = 0.57 Exposed length of previously buried pipe/cable etc.Exposed bridge footing(s) Fracture lines along top of bankExposed sanitary/storm sewer/pipeline etc. Exposed building foundationElevated stormsewer outfall(s) n/10 = 0.30Undermined gabion baskets/concrete aprons etc. 1 Formation of chute(s)Scour pools d/s of culverts/stormsewer outlets Single thread channel to multiple channelCut face on bar forms Evolution of pool-riffle form to low bed relief formHead cutting due to knick point migration Cut-off channel(s)

Agg

rada

tion

Deg

rada

tion

Wid

enin

gtr

ic F

orm

Head cutting due to knick point migration Cut off channel(s)Terrace cut through older bar material Formation of island(s) 1Suspended armour layer visible in bank Thalweg alignment out of phase meander formChannel worn into undisturbed overburden/bedrock Bar forms poorly formed/reworked/removed





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100-78 77-53 52-28 27-0 100-78 77-53 52-28 27-0







100-83 82-59 58-31 30-0 100-80 80-56 55-30 29-0

▼ Looking upstream at crossing showing riffle in foreground created by partially failed former rip-rap placementfailed former rip rap placement

References




▲ Overview looking downstream from Conlin Rd. - mixed groundcover and swamp forest riparian zone


Project: Conlin Road East EAEast Oshawa Creek Tributary B. de Geus 03.12



Lobate bar Fallen/leaning trees/fence posts etc.Coarse material in riffles embedded Occurrence of Large Organic Debrisn Coarse material in riffles embedded Occurrence of Large Organic DebrisSiltation in pools 1 Exposed tree rootsMedial bars Basal scour on inside meander bends 1Accretion on point bars Basal scour on both sides of channel through riffle 1Poor longitudinal sorting of bed materials Gabion baskets/concrete walls etc. out flankedDeposition in the overbank zone Length of basal scour >50% through subject reach

n/7 = 0.14 Exposed length of previously buried pipe/cable etc.Exposed bridge footing(s) Fracture lines along top of bankExposed sanitary/storm sewer/pipeline etc. Exposed building foundationElevated stormsewer outfall(s) n/10 = 0.20Undermined gabion baskets/concrete aprons etc. Formation of chute(s)Scour pools d/s of culverts/stormsewer outlets Single thread channel to multiple channelCut face on bar forms Evolution of pool-riffle form to low bed relief formHead cutting due to knick point migration Cut-off channel(s)

Agg

rada

tion

Deg

rada

tion

Wid

enin

gtr

ic F

orm

Head cutting due to knick point migration Cut off channel(s)Terrace cut through older bar material Formation of island(s)Suspended armour layer visible in bank Thalweg alignment out of phase meander formChannel worn into undisturbed overburden/bedrock Bar forms poorly formed/reworked/removed 1





D

Pla

nim

et








100-78 77-53 52-28 27-0 100-78 77-53 52-28 27-0







100-83 82-59 58-31 30-0 100-80 80-56 55-30 29-0

▼ Looking upstream through culvert face▼ Looking upstream through culvert face showing low flow transition

References




▲ Overview looking upstream from Conlin Rd. - active channel heavilyencroached with vegetation


Project: Conlin Road East EAEast Oshawa Creek Tributary B. de Geus 03.12



Lobate bar Fallen/leaning trees/fence posts etc. 1Coarse material in riffles embedded 1 Occurrence of Large Organic Debris 1n Coarse material in riffles embedded 1 Occurrence of Large Organic Debris 1Siltation in pools 1 Exposed tree roots 1Medial bars Basal scour on inside meander bends 1Accretion on point bars Basal scour on both sides of channel through riffle 1Poor longitudinal sorting of bed materials 1 Gabion baskets/concrete walls etc. out flankedDeposition in the overbank zone Length of basal scour >50% through subject reach

n/7 = 0.43 Exposed length of previously buried pipe/cable etc.Exposed bridge footing(s) Fracture lines along top of bankExposed sanitary/storm sewer/pipeline etc. Exposed building foundationElevated stormsewer outfall(s) n/10 = 0.50Undermined gabion baskets/concrete aprons etc. Formation of chute(s)Scour pools d/s of culverts/stormsewer outlets 1 Single thread channel to multiple channelCut face on bar forms Evolution of pool-riffle form to low bed relief formHead cutting due to knick point migration 1 Cut-off channel(s)

Agg

rada

tion

Deg

rada

tion

Wid

enin

gtr

ic F

orm

Head cutting due to knick point migration 1 Cut off channel(s)Terrace cut through older bar material Formation of island(s)Suspended armour layer visible in bank Thalweg alignment out of phase meander formChannel worn into undisturbed overburden/bedrock 1 Bar forms poorly formed/reworked/removed 1





D

Pla

nim

et








100-78 77-53 52-28 27-0 100-78 77-53 52-28 27-0







100-83 82-59 58-31 30-0 100-80 80-56 55-30 29-0

▼ Looking downstream through typical partially entrenched conditions, with erosion scars, exposed roots, , p ,and knickpoint development

References




▲ Overview looking downstream from Conlin Rd. at creek level - mixed groundcover and immature forest riparian zone


Project: Conlin Road East EAHarmony Creek Tributary West B. de Geus 03.12



Lobate bar Fallen/leaning trees/fence posts etc.Coarse material in riffles embedded Occurrence of Large Organic Debris 1n Coarse material in riffles embedded Occurrence of Large Organic Debris 1Siltation in pools 1 Exposed tree rootsMedial bars Basal scour on inside meander bends 1Accretion on point bars Basal scour on both sides of channel through riffle 1Poor longitudinal sorting of bed materials Gabion baskets/concrete walls etc. out flankedDeposition in the overbank zone Length of basal scour >50% through subject reach


Agg

rada

tion

Deg

rada

tion

Wid

enin

gtr

ic F

orm

Head cutting due to knick point migration Cut off channel(s)Terrace cut through older bar material Formation of island(s)Suspended armour layer visible in bank Thalweg alignment out of phase meander formChannel worn into undisturbed overburden/bedrock Bar forms poorly formed/reworked/removed





D

Pla

nim

et








100-78 77-53 52-28 27-0 100-78 77-53 52-28 27-0







100-83 82-59 58-31 30-0 100-80 80-56 55-30 29-0

▼ Looking westerly along roadside alignment of tributary againstalignment of tributary against retaining wall

References




▲ Overview looking upstream from Conlin Rd. - active channel heavily encroached with vegetation


Project: Conlin Road East EAHarmony Creek Tributary West B. de Geus 03.12



Lobate bar Fallen/leaning trees/fence posts etc.Coarse material in riffles embedded Occurrence of Large Organic Debrisn Coarse material in riffles embedded Occurrence of Large Organic DebrisSiltation in pools 1 Exposed tree rootsMedial bars Basal scour on inside meander bends 1Accretion on point bars Basal scour on both sides of channel through riffle 1Poor longitudinal sorting of bed materials Gabion baskets/concrete walls etc. out flankedDeposition in the overbank zone Length of basal scour >50% through subject reach


Agg

rada

tion

Deg

rada

tion

Wid

enin

gtr

ic F

orm






D

Pla

nim

et








100-78 77-53 52-28 27-0 100-78 77-53 52-28 27-0







100-83 82-59 58-31 30-0 100-80 80-56 55-30 29-0

▼ Looking upstream into existing crossing - heavily encroached withcrossing heavily encroached with vegetation

References




▲ Overview looking downstream from Conlin Rd. - active channel heavily encroached with vegetation


Project: Conlin Road East EAHarmony Creek Tributary East B. de Geus 03.12



Lobate bar Fallen/leaning trees/fence posts etc.Coarse material in riffles embedded Occurrence of Large Organic Debris 1n Coarse material in riffles embedded Occurrence of Large Organic Debris 1Siltation in pools 1 Exposed tree roots 1Medial bars Basal scour on inside meander bendsAccretion on point bars Basal scour on both sides of channel through rifflePoor longitudinal sorting of bed materials Gabion baskets/concrete walls etc. out flankedDeposition in the overbank zone Length of basal scour >50% through subject reach

n/7 = 0.14 Exposed length of previously buried pipe/cable etc.Exposed bridge footing(s) Fracture lines along top of bankExposed sanitary/storm sewer/pipeline etc. Exposed building foundationElevated stormsewer outfall(s) n/10 = 0.20Undermined gabion baskets/concrete aprons etc. Formation of chute(s)Scour pools d/s of culverts/stormsewer outlets Single thread channel to multiple channel 1Cut face on bar forms Evolution of pool-riffle form to low bed relief formHead cutting due to knick point migration Cut-off channel(s)

Agg

rada

tion

Deg

rada

tion

Wid

enin

gtr

ic F

orm






D

Pla

nim

et








100-78 77-53 52-28 27-0 100-78 77-53 52-28 27-0







100-83 82-59 58-31 30-0 100-80 80-56 55-30 29-0

▼ Detail of tile drain outlet from north westerly corn field on upstream face y pof crossing

References




▲ Overview looking upstream from Conlin Rd. - active channel heavily encroached with vegetation


Project: Conlin Road East EAHarmony Creek Tributary East B. de Geus 03.12



Lobate bar Fallen/leaning trees/fence posts etc.Coarse material in riffles embedded 1 Occurrence of Large Organic Debrisn Coarse material in riffles embedded 1 Occurrence of Large Organic DebrisSiltation in pools 1 Exposed tree rootsMedial bars Basal scour on inside meander bends 1Accretion on point bars Basal scour on both sides of channel through rifflePoor longitudinal sorting of bed materials 1 Gabion baskets/concrete walls etc. out flankedDeposition in the overbank zone Length of basal scour >50% through subject reach


Agg

rada

tion

Deg

rada

tion

Wid

enin

gtr

ic F

orm






D

Pla

nim

et







u/s R 8 10-8 7-6 5-3 2-0 u/s R 14 10-8 7-6 5-3 2-0/200 107 /200 144/100 53.5 Optimal Good Fair Poor /100 72 Optimal Good Fair Poor

100-78 77-53 52-28 27-0 100-78 77-53 52-28 27-0






/100 48.0 Optimal Good Fair Poor (RGA + RHA + RSAT) / 3 = 93 Optimal Good Fair Poor

100-83 82-59 58-31 30-0 100-80 80-56 55-30 29-0

▼ Looking upstream towards Conlin rd. - steep riffle after first meander pbend

References




▲ Overview looking downstream from Conlin Rd. - recently constructed natural channel corridor

East Oshawa CreekEast Oshawa CreekHistoric Planform ComparisonHistoric Planform Comparison p

20122012

1971 1981971 19871987

N▲N▲N▲

not to scalenot to scale

E t O h C k T ib tEast Oshawa Creek Tributaryy

Historic Planform ComparisonHistoric Planform Comparison

20122012

19871971 19871971

N ▲N ▲


Harmony Creek West TributaryHi t i Pl f C iHistoric Planform Comparison

1971

2012

19711987

N ▲

not to scale

H C k E t T ib tHarmony Creek East TributaryHarmony Creek East TributaryHi t i Pl f C iHistoric Planform ComparisonHistoric Planform Comparison

20122012

1971 19871971 1987

N ▲N ▲


Conlin Road East EACrossing Width Opening Sizing per MNR Guidelines (2002)

bankfull width field measurements

(m)

East Oshawa Creek (7.4+7.7+6.9+7.0+7.9)/5=7.4East Oshawa Creek Tributary (3.4+3.6+3.9+3.1+3.5)/5=3.5

Harmony Creek Trib West (2.4+2.8+2.9+2.6+2.3)/5=2.6Harmony Creek Trib East variable 4 5m new NCD construction / say = 4 5mHarmony Creek Trib East variable 4-5m, new NCD construction / say = 4.5m

recommended existingbankfull width erosion allowance opening width opening width

(m) (m) (m) (m)

East Oshawa Creek 7.4 + (2 x 2m) = 11.4 12.2East Oshawa Creek 7.4 (2 x 2m) 11.4 12.2East Oshawa Creek Tributary 3.5 + (2 x 1m) = 5.5 3.6

Harmony Creek Trib West 2.6 + (2 x 1m) = 4.6 8.0 *

Harmony Creek Trib East 4.5 + (2 x 1m) = 6.5 7.3 *

* - new structures 2014/2013

<5m 5-30m >30m

Range of Suggested Toe Erosion Allowances

No Evidence of Active Erosion or

Evidence of Active Erosion or Bankfull Flow Velocity <

Bankfull Flow Velocity > Competent Flow Velocity

Competent Flow Velocity Bankfull Width

Native Soil Structure

H d R k ( it )Hard Rock (granite)0-2m 0m 1m

Soft Rock (shale, limestone),2-5m 0m 1m 2m

Cobbles, Boulders

0m

Stiff/Hard Cohesive Soil (clays,5-8m 1m 2m 4m

clay silt), Coarse Granular (gravels), Till

Soft/Firm Cohesive Soil, Loose

i) Where a combination of different native soil structures occurs, the greater or largest range of applicable to erosionallowances for the materials found at the site should be appliedii) Active Erosion is defined as: bank material is exposed directly to stream flow under normal or flood flow conditions

Soft/Firm Cohesive Soil, Loose8-15m 1-2m 5m 7m

Granular (sand, silt), Fill

where undercutting, over-steepening, slumping of a bank or down stream sediment loading is occurring. An area mayhave erosion but there may not be evidence of 'active erosion' either as a result of well rooted vegetation or as a result of a condition of net sediment deposition. The area may still suffer erosion at some point in the future as a result of shifting of the channeliii) Competent Flow Velocity is the flow velocity that the bed material in the stream can support without resulting in erosion or scour (OMNR 2002)

result of shifting of the channel

GEO-ROX v.1.6 Rock Size Treatment Model

Project: Conlin Road East EAEast Oshawa Creek

Required Scour Protection Treatment B. de Geus 01.11

USDA Isbash Method Newbury-Fischenich Method

Notation: Input:

calc (N m-2)

Vi = Isbash velocity Shear pulse adjustment factor (Fs) 1.0

W = average rock weight Dcrit (gr-co) (cm) 0

g (kg m-3) River stone gradation and sub-pavement depth:

dolomite 2900 low turbulence Q high turbulence Q

granite 2800 lower limit (cm) upper limit (cm)

limestone 2650 D100 0.0 0.0

pure shale 2400 D85 0.0 0.0

calcareous shale 2600 D50 0.0 0.0

sandstone 2500 D30 0.0 0.0

D15 0.0 0.0

Input: sub-pavement depth 0.0 0.0

design storm frequency 100yr

mean channel velocity (Vmean) 2.64 m s-1 Angular gradation and sub-pavement depth:

Isbash adjustment factor (Fv) 1.3

density of rock (g) 2650 kg m-3 low turbulence Q high turbulence Q

lower limit (cm) upper limit (cm)

D100 0.0 0.0

Vi W required D85 0.0 0.0

3.43 m s-1 109.2 kg D50 0.0 0.0

D30 0.0 0.0

D15 0.0 0.0

Equivalent average diameters:

sub-pavement depth 0.0 0.0

D50 cube 34.5 cm 13.6 inches

D50 river stone 42.9 cm 16.9 inches

D50 angular 38.7 cm 15.2 inches Dimensionless Shear

Shields-Rosgen Method (C3-C4 channel type)

River stone gradation and sub-pavement depth: River stone gradation and sub-pavement depth:

low turbulence Q high turbulence Q low turbulence Q high turbulence Q

lower limit (cm) upper limit (cm) lower limit (cm) upper limit (cm)

D100 64.3 85.7 D100 41.6 55.4

D85 55.7 77.1 D85 36.0 49.9

D50 42.9 64.3 D50 27.7 41.6

D30 25.7 30.0 D30 16.6 19.4

D15 12.9 21.4 D15 8.3 13.9

sub-pavement depth 85.7 128.6 sub-pavement depth 55.4 83.2

Angular gradation and sub-pavement depth: Angular gradation and sub-pavement depth:



D100 58.1 77.4 D100 37.5 50.1

D85 50.3 69.7 D85 32.5 45.1

D50 38.7 58.1 D50 25.0 37.5

D30 23.2 27.1 D30 15.0 17.5

D15 11.6 19.4 D15 7.5 12.5


1 of 1

Threshold Velocity Threshold Shear Stress


Project: Tributary B Road Crossing AnalysisEast Oshawa Creek Tributary



Notation: Input:

calc (N m-2)






limestone 2650 D100 0.0 0.0

pure shale 2400 D85 0.0 0.0


sandstone 2500 D30 0.0 0.0

D15 0.0 0.0


design storm frequency 100yr





D100 0.0 0.0


3.78 m s-1 195.9 kg D50 0.0 0.0

D30 0.0 0.0

D15 0.0 0.0










D100 78.1 104.1 D100 50.5 67.4

D85 67.7 93.7 D85 43.8 60.6

D50 52.1 78.1 D50 33.7 50.5

D30 31.2 36.5 D30 20.2 23.6

D15 15.6 26.0 D15 10.1 16.8





D100 70.5 94.0 D100 45.6 60.8

D85 61.1 84.6 D85 39.5 54.7

D50 47.0 70.5 D50 30.4 45.6

D30 28.2 32.9 D30 18.2 21.3

D15 14.1 23.5 D15 9.1 15.2


1 of 1



Project: Tributary B Road Crossing AnalysisHarmony Creek Tributary West



Notation: Input:

calc (N m-2)






limestone 2650 D100 0.0 0.0

pure shale 2400 D85 0.0 0.0


sandstone 2500 D30 0.0 0.0

D15 0.0 0.0


design storm frequency Greck Regulatory





D100 0.0 0.0


2.46 m s-1 14.7 kg D50 0.0 0.0

D30 0.0 0.0

D15 0.0 0.0










D100 32.9 43.9 D100 21.3 28.4

D85 28.6 39.5 D85 18.5 25.6

D50 22.0 32.9 D50 14.2 21.3

D30 13.2 15.4 D30 8.5 9.9

D15 6.6 11.0 D15 4.3 7.1





D100 29.8 39.7 D100 19.2 25.7

D85 25.8 35.7 D85 16.7 23.1

D50 19.8 29.8 D50 12.8 19.2

D30 11.9 13.9 D30 7.7 9.0

D15 6.0 9.9 D15 3.8 6.4


1 of 1



Project: Tributary B Road Crossing AnalysisHarmony Creek Tributary East



Notation: Input:

calc (N m-2)






limestone 2650 D100 0.0 0.0

pure shale 2400 D85 0.0 0.0


sandstone 2500 D30 0.0 0.0

D15 0.0 0.0


design storm frequency Greck Regulatory





D100 0.0 0.0


3.28 m s-1 82.6 kg D50 0.0 0.0

D30 0.0 0.0

D15 0.0 0.0










D100 58.6 78.1 D100 37.9 50.5

D85 50.8 70.3 D85 32.8 45.5

D50 39.1 58.6 D50 25.3 37.9

D30 23.4 27.3 D30 15.2 17.7

D15 11.7 19.5 D15 7.6 12.6





D100 52.9 70.5 D100 34.2 45.6

D85 45.8 63.5 D85 29.7 41.1

D50 35.3 52.9 D50 22.8 34.2

D30 21.2 24.7 D30 13.7 16.0

D15 10.6 17.6 D15 6.8 11.4


1 of 1


Conlin Road East EAConlin Road East EACrossing Scour Protection per MTO Standards (2008)

Velocity from HECRAS

(m s-1)East Oshawa Creek 2.64 (100yr)

East Oshawa Creek Easterly Trib 2.91 (100yr)Harmony Creek Trib West 1.89 (Reg.)Harmony Creek Trib East 2.52 (Reg.)

D15 D30 D50 D84 D100

(cm) (cm) (cm) (cm) (cm)(cm) (cm) (cm) (cm) (cm)

Angular Stone

East Oshawa Creek 19.4 27.1 58.1 69.7 77.4East Oshawa Creek Easterly Trib 23.5 32.9 70.5 84.6 94.0

Harmony Creek Trib West 9.9 13.9 29.8 35.7 39.7 (i)Harmony Creek Trib East 19.9 27.9 59.8 71.8 79.8

River Stone

East Oshawa Creek 21.4 30.0 64.3 77.1 85.7East Oshawa Creek Easterly Trib 26.0 36.5 78.1 93.7 104.1

Harmony Creek Trib West 11.0 15.4 32.9 39.5 43.9Harmony Creek Trib East 17.6 24.7 52.9 63.5 70.5

(ii) - partially satisfied by OPSS 1004 R-50 rip-rap up to the D50 level(ii) partially satisfied by OPSS 1004 R 50 rip rap up to the D50 level

stone treatment overbank treatment (ii) bed treatment (iii)

layer thickness layer thickness layer thickness

(cm) (cm) (cm)

East Oshawa Creek 130 20 20East Oshawa Creek Easterly Trib 160 10 10

Harmony Creek Trib West 70 10 10Harmony Creek Trib East 120 10 10

(ii) - satisfied by native excavation clay-silt with some granular material, tamped in place

(iii) - satisfied by native granular material with some fines and some gravel-cobble, tamped in place

1

City Manager Approval

Third-Party Source

January 11, 2017

The City of Oshawa is committed to creating an accessible online experience by making web content available to everyone. The City makes it a priority to provide website documents in an accessible format, however the attached document is not accessible as the City is not the author of the document. If this information is required in an accessible format, please contact Service Oshawa; Telephone: 905-436-3311, or email: [email protected] or in person at City Hall, 50 Centre Street South, Oshawa.

appendix g fluvial geomorphologic assessment · aqualogic. 3 . at the time of field work the...

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