hydraulic assessment report - oakville planning/da-161116...chl (m3/s) (m) (m) (m) (m) (m/m) (m/s)...

HYDRAULIC ASSESSMENT REPORT

514 South Service Road First Gulf Corporation 3751 Victoria Park Avenue Toronto, ON M1W 3Z4

1814292-000-W01

August 2014

Hydraulic Assessment Report | 514 South Service Road

MMM Group Limited | August 2014 | 18-14292-000-W01

i

TABLE OF CONTENTS

1.0 INTRODUCTION ............................................................................................ 1

2.0 SCOPE OF WORK ......................................................................................... 1

3.0 EXISTING HYDRAULIC MODELLING ........................................................... 3

4.0 PROPOSED HYDRAULIC MODELLING ....................................................... 7

5.0 CONCLUSIONS ............................................................................................. 9

LIST OF FIGURES

Figure 1: Study Area ................................................................................................................................. 2

Figure 2: Existing Regulatory Floodline .................................................................................................... 5

Figure 3: Proposed Regulatory Floodline ................................................................................................. 8

LIST OF TABLES

Table 1: Comparison of HEC-2 and HEC-RAS Regulatory Event Water Surface Elevations ................. 4

Table 2: Existing Hydraulic Assessment Results ..................................................................................... 6

Table 3: Comparison of Existing and Proposed Hydraulic Assessments ................................................ 7

LIST OF APPENDICES

Appendix A – HEC-RAS Results



1

1.0 INTRODUCTION

MMM Group Ltd was retained by First Gulf Corporation to determine the hydraulic implications

of the proposed development at 514 South Service Road on the Lower Morrison Creek adjacent

to the project site. The proposed development works at 514 South Service Road includes a

proposed 4-storey Office Building and a proposed parking lot. The study area is shown in Figure

1. The Lower Morrison Creek is located west of the study area, which is under the jurisdiction of

Conservation Halton (CH). The hydraulic assessment is to be conducted for the Lower Morrison

Creek adjacent to the project site.

2.0 SCOPE OF WORK

The objective of this study is to conduct a hydraulic assessment of the Lower Morrison Creek

adjacent to the project site for determining the hydraulic impact resulting from the proposed

developments at 514 South Service Road.



3

3.0 EXISTING HYDRAULIC MODELLING

The study area is located south of South Service Road and the QEW, west of Chartwell Road,

east of Lower Morrison Creek. The CNR tracks are located approximately 260 m south of the

project site. The Lower Morrison Creek flows southerly through QEW and the South Service

Road culverts, and remains as an open channel adjacent to the project site. However,

immediately south of the project site the Lower Morrison Creek is conveyed by a CSP arched

culvert (approximately 25 m in length). Afterwards the Lower Morrison Creek remains as an

open channel for approximately 200 m. Thereafter, the Lower Morrison Creek remains

completely confined and channelized, as it is conveyed by culverts under the CNR tracks,

private properties and Cornwall Road. Finally it confluences with Wedgewood Creek east of

Chartwell Road before discharging to Lake Ontario.

A hydraulic model in the form of HEC-2 was obtained from CH for the Lower Morrison Creek

and Wedgwood Creeks. These hydraulic models were developed as a part of the Flood, Erosion

and Master Drainage Plan Study, prepared by R. V. Anderson and Associates (1993). It should

be noted that the HEC-2 hydraulic model extends from the south of the CNR tracks, but does

not simulate the channelized and confined sections of the Lower Morrison Creek south of the

CNR tracks and does not extend up to the project site, hence should be considered outdated.

The HEC-2 model obtained from CH was initially converted to HEC-RAS. The converted HEC-

RAS model was updated with a box culvert located between the CNR tracks and the Cornwall

Road, and Cornwall Road double culvert.

The model was then rerun to establish a baseline performance based solely on the updated

hydraulic subroutines present in the HEC-RAS software. Table 1 presents the updated results

and compares them to the original floodplain elevations obtained from CH’s floodplain mapping.



4

Table 1: Comparison of HEC-2 and HEC-RAS Regulatory Event Water Surface Elevations

Model Cross-Section

Original CH HEC-2

Water Surface Elevation (as shown on

floodplain mapping)

MMM Converted HEC-RAS

Water Surface Elevation

2.82 n/a 100.71

2.805 (U/S inlet of site

culvert)

n/a 100.71

2.74 (D/S outlet of

site culvert)

n/a 99.09

2.73 98.96 98.96

2.68 98.37 98.37

2.64 97.78 97.79

2.59 97.17 96.94

2.54 96.54 96.54

2.49 96.06 96.09

2.43 95.67 95.71

Table 1 shows excellent agreement between the values reported on the floodplain mapping and

the results from the converted HEC-RAS model (referred to as the MMM converted HEC-RAS

model). Therefore, the results of the HEC-RAS mapping may be interpreted as reasonable

approximations of floodplain behaviour utilizing the out-dated assumptions and therefore as a

baseline simulation for comparison. The MMM converted HEC-RAS model was modified even

further by extending the model north of the CNR tracks up to the project site. New sections were

created from up-to-date contour mapping adjacent to the project site and the arched culvert (1.4

m span and 1.1 m rise) located south of the project site were inserted in the MMM converted

HEC-RAS model. The results for the existing MMM converted HEC-RAS model are shown in

Table 2 (shown in Appendix A). Table 2 shows the Regulatory water surface elevations. Figure

2 shows the Regulatory flood lines in the Lower Morrison Creek adjacent to the project site.



6

Table 2: Existing Hydraulic Assessment Results

Reach River Sta Profile Q Total

Min Ch

El

W.S.

Elev Crit W.S. E.G. Elev

E.G.

Slope Vel Chnl

Flow

Area

Top

Width

Froude #

Chl

(m3/s) (m) (m) (m) (m) (m/m) (m/s) (m2) (m)

Reach-1 3.5 PF 4 16.8 103.89 105.51 105.24 105.78 0.004978 2.59 9.35 10.31 0.67

Reach-1 3.49 PF 4 16.8 103.75 105.47 105.68 0.003616 2.31 11.08 15.01 0.58

Reach-1 3.48 PF 4 16.8 103.97 105.43 105.08 105.63 0.003772 2.25 11.31 13.39 0.6

Reach-1 3.47 PF 4 16.8 103.89 105.07 105.07 105.51 0.0111 3.22 6.94 9.44 0.98

Reach-1 3.46 PF 4 16.8 103.29 104.67 104.12 104.75 0.001605 1.36 16.27 17.44 0.38

Reach-1 3.45 PF 4 16.8 103 104.3 104.3 104.68 0.010545 3.35 8.35 12.14 0.97

Reach-1 3.44 PF 4 16.8 102.54 103.65 103.74 104.2 0.018772 3.94 6.2 8.07 1.24

Reach-1 3.43 PF 4 16.8 102 103.27 103.16 103.61 0.00713 2.8 8.44 12.09 0.8

Reach-1 3.42 PF 4 16.8 101.3 103.33 102.89 103.46 0.002081 1.99 15.39 16.61 0.45

Reach-1 3.41 PF 4 16.8 101.3 103.3 102.89 103.44 0.002237 2.04 14.92 16.38 0.47



7

4.0 PROPOSED HYDRAULIC MODELLING

Under the proposed condition, to reflect the changes due to the proposed site grading plan and

proposed developments, new cross-sections were generated for determining the proposed

hydraulic assessment. These cross-sections were inserted in the proposed MMM converted HEC-

RAS model. The results from the proposed MMM converted HEC-RAS model are shown in

Table 3 (shown in Appendix A). Figure 3 shows the Regulatory flood lines in the Lower Morrison

Creek adjacent to the project site.

Table 3: Comparison of Existing and Proposed Hydraulic Assessments

Existing

W.S.

Elev

Proposed

W.S. Elev

Existing

Vel Chnl

Proposed

Vel Chnl

Reach

River

Sta Profile Q Total Diff Diff

(m3/s) (m) (m) (m) (m/s) (m/s) (m/s)

Reach-1 3.5 PF 4 16.8 105.42 105.51 0.09 2.79 2.59 -0.2

Reach-1 3.49 PF 4 16.8 105.35 105.47 0.12 2.6 2.31 -0.29

Reach-1 3.48 PF 4 16.8 105.28 105.43 0.15 2.59 2.25 -0.34

Reach-1 3.47 PF 4 16.8 105.21 105.07 -0.14 2.46 3.22 0.76

Reach-1 3.46 PF 4 16.8 104.67 104.67 0 1.37 1.36 -0.01

Reach-1 3.45 PF 4 16.8 104.29 104.3 0.01 3.35 3.35 0

Reach-1 3.44 PF 4 16.8 103.65 103.65 0 3.9 3.94 0.04

Reach-1 3.43 PF 4 16.8 103.27 103.27 0 2.8 2.8 0

Reach-1 3.42 PF 4 16.8 103.33 103.33 0 1.99 1.99 0

Reach-1 3.41 PF 4 16.8 103.3 103.3 0 2.04 2.04 0

Table 3 shows that under the proposed condition the Regulatory water surface elevation

increases by a maximum of 0.15 m adjacent to the project site. However, under the proposed

condition changes in the site grading plan ensures that the Regulatory water surface elevations

remain within the channel corridor. Table 3 also shows that the increase in the water surface

elevations at specific sections also causes the average channel velocities to reduce adjacent to

the project site compared to the existing condition. It should be noted that no hydraulic impact

was observed in terms of the water surface elevations downstream of the project site.



9

5.0 CONCLUSIONS

The following conclusions can be reached from the preceding assessment:

1. The existing outdated HEC-2 model was modified, updated and extended to reflect certain

downstream culverts and the existing project site.

2. Regulatory flood lines were plotted for both existing and proposed conditions adjacent to

the project site.

3. Under the proposed condition the minor increase in Regulatory water surface elevation

remains within the watercourse corridor.

4. Under the proposed condition the average channel velocities decrease compared to the

existing condition.

5. Under the proposed condition, there was no hydraulic impact downstream of the project

site.

Respectfully submitted by MMM Group Limited

Asif Quader, P. Eng., Ph.D. Project Engineer Water Resources

Stamped by Maggie Ding on behalf of Asif Quader upon his absence

AP

PE

ND

IX A

– H

EC

-RA

S R

ES

UL

TS

1814292: 514 South Service Road

Existing Condition Hydraulic Assessment

Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl

(m3/s) (m) (m) (m) (m) (m/m) (m/s) (m2) (m)

Reach-1 3.5 PF 4 16.8 103.89 105.42 105.25 105.74 0.00626 2.79 8.44 9.66 0.75

Reach-1 3.49 PF 4 16.8 103.75 105.35 104.99 105.62 0.005131 2.6 10.51 17.81 0.69

Reach-1 3.48 PF 4 16.8 103.97 105.28 105.13 105.54 0.005845 2.59 10.78 19.92 0.73

Reach-1 3.47 PF 4 16.8 103.89 105.21 105.21 105.44 0.005514 2.46 13.15 34.12 0.7

Reach-1 3.46 PF 4 16.8 103.29 104.67 104.13 104.75 0.00162 1.37 16.81 21.85 0.38

Reach-1 3.45 PF 4 16.8 103 104.29 104.29 104.68 0.010577 3.35 8.34 12.13 0.97

Reach-1 3.44 PF 4 16.8 102.54 103.65 103.73 104.19 0.018288 3.9 6.26 8.1 1.22

Reach-1 3.43 PF 4 16.8 102 103.27 103.15 103.61 0.007159 2.8 8.42 12.07 0.8

Reach-1 3.42 PF 4 16.8 101.3 103.33 102.89 103.46 0.002087 1.99 15.37 16.6 0.45

Reach-1 3.41 PF 4 16.8 101.3 103.3 102.89 103.44 0.002245 2.04 14.9 16.37 0.47

Reach-1 3.4 Culvert

Reach-1 2.93 PF 4 16.8 101.12 102.26 102.25 102.27 0.000678 0.57 29.28 42.9 0.22

Reach-1 2.92 PF 4 16.8 101.02 102.25 102.25 102.27 0.000443 0.5 33.33 42.9 0.18

Reach-1 2.91 PF 4 16.8 100.68 101.03 101.27 102.08 0.199906 4.54 3.7 17.43 3.15

Reach-1 2.9 PF 4 16.8 100.34 101.08 100.93 101.16 0.006185 1.24 13.5 32.71 0.62

Reach-1 2.858 PF 4 16.8 100 100.97 101 0.001659 0.76 22.08 41.73 0.33

Reach-1 2.84 PF 4 16.8 99 100.64 100.64 100.92 0.008416 2.68 10.21 21.39 0.79

Reach-1 2.83 PF 4 16.8 98.59 100.12 100.32 100.74 0.030313 3.49 4.99 10.85 1.38

Reach-1 2.829 PF 4 16.8 98.37 100.54 99.11 100.54 0.000104 0.49 78.58 83.83 0.11

1814292: 514 South Service Road

Porposed Condition Hydraulic Assessment

Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl

(m3/s) (m) (m) (m) (m) (m/m) (m/s) (m2) (m)

Reach-1 3.5 PF 4 16.8 103.89 105.51 105.24 105.78 0.004978 2.59 9.35 10.31 0.67

Reach-1 3.49 PF 4 16.8 103.75 105.47 105.68 0.003616 2.31 11.08 15.01 0.58

Reach-1 3.48 PF 4 16.8 103.97 105.43 105.08 105.63 0.003772 2.25 11.31 13.39 0.6

Reach-1 3.47 PF 4 16.8 103.89 105.07 105.07 105.51 0.0111 3.22 6.94 9.44 0.98

Reach-1 3.46 PF 4 16.8 103.29 104.67 104.12 104.75 0.001605 1.36 16.27 17.44 0.38

Reach-1 3.45 PF 4 16.8 103 104.3 104.3 104.68 0.010545 3.35 8.35 12.14 0.97

Reach-1 3.44 PF 4 16.8 102.54 103.65 103.74 104.2 0.018772 3.94 6.2 8.07 1.24

Reach-1 3.43 PF 4 16.8 102 103.27 103.16 103.61 0.00713 2.8 8.44 12.09 0.8

Reach-1 3.42 PF 4 16.8 101.3 103.33 102.89 103.46 0.002081 1.99 15.39 16.61 0.45

Reach-1 3.41 PF 4 16.8 101.3 103.3 102.89 103.44 0.002237 2.04 14.92 16.38 0.47

Reach-1 3.4 Culvert

Reach-1 2.93 PF 4 16.8 101.12 102.26 102.25 102.27 0.000678 0.57 29.28 42.9 0.22

Reach-1 2.92 PF 4 16.8 101.02 102.25 102.25 102.27 0.000443 0.5 33.33 42.9 0.18

Reach-1 2.91 PF 4 16.8 100.68 101.03 101.27 102.08 0.199906 4.54 3.7 17.43 3.15

Reach-1 2.9 PF 4 16.8 100.34 101.08 100.93 101.16 0.006185 1.24 13.5 32.71 0.62

Reach-1 2.858 PF 4 16.8 100 100.97 101 0.001659 0.76 22.08 41.73 0.33

Reach-1 2.84 PF 4 16.8 99 100.64 100.64 100.92 0.008416 2.68 10.21 21.39 0.79

Reach-1 2.83 PF 4 16.8 98.59 100.12 100.32 100.74 0.030313 3.49 4.99 10.85 1.38

Reach-1 2.829 PF 4 16.8 98.37 100.54 99.11 100.54 0.000104 0.49 78.58 83.83 0.11

hydraulic assessment report - oakville planning/da-161116...chl (m3/s) (m) (m) (m) (m) (m/m) (m/s)...

Documents