Cooksville Creek Flood Evaluation July 2012 Master Plan EA Aquafor Beech Ltd

Cooksville Creek Flood Evaluation July 2012 Master Plan EA

APPENDIX A

Catchment Delineation for Flood Storage Sites

Aquafor Beech Ltd. Ref: 65109 A1 Cooksville Creek Flood Evaluation July 2012 Master Plan EA

Site 1

Aquafor Beech Ltd. Ref: 65109 A2 Cooksville Creek Flood Evaluation July 2012 Master Plan EA

Site 2

Aquafor Beech Ltd. Ref: 65109 A3 Cooksville Creek Flood Evaluation July 2012 Master Plan EA

Site 3

Aquafor Beech Ltd. Ref: 65109 A4 Cooksville Creek Flood Evaluation July 2012 Master Plan EA

Site 4

Aquafor Beech Ltd. Ref: 65109 A5 Cooksville Creek Flood Evaluation July 2012 Master Plan EA

Site 5

Aquafor Beech Ltd. Ref: 65109 A6 Cooksville Creek Flood Evaluation July 2012 Master Plan EA

Site 6

Aquafor Beech Ltd. Ref: 65109 A7 Cooksville Creek Flood Evaluation July 2012 Master Plan EA

Site 7

Aquafor Beech Ltd. Ref: 65109 A8 Cooksville Creek Flood Evaluation July 2012 Master Plan EA

Site 8

Aquafor Beech Ltd. Ref: 65109 A9 Cooksville Creek Flood Evaluation July 2012 Master Plan EA

Site 9

Aquafor Beech Ltd. Ref: 65109 A10 Cooksville Creek Flood Evaluation July 2012 Master Plan EA

Site 10

Aquafor Beech Ltd. Ref: 65109 A11 Cooksville Creek Flood Evaluation July 2012 Master Plan EA

Site 11

Aquafor Beech Ltd. Ref: 65109 A12 Cooksville Creek Flood Evaluation July 2012 Master Plan EA

Site 12

Aquafor Beech Ltd. Ref: 65109 A13 Cooksville Creek Flood Evaluation July 2012 Master Plan EA

Site 13

Aquafor Beech Ltd. Ref: 65109 A14 Cooksville Creek Flood Evaluation July 2012 Master Plan EA

APPENDIX B

Hydrologic and Hydraulic Modeling

Aquafor Beech Ltd. Ref: 65109 B1 Cooksville Creek Flood Evaluation July 2012 Master Plan EA

Introduction and Summary

Modifications of the Cooksville Creek SWMHYMO model were made in July of 2011 to test the benefit of using upper-basin offline storage to reduce peak flows for larger wet weather events. Modifications included development of new model inputs for a damaging storm that occurred on August 4, 2009, insertion of proposed storage basins developed in coordination with Aquafor Beech Ltd in model sub basins using the route reservoir command in the model, modifying the outflow-storage relationships for each storage basin to optimize peak flow reduction, and quantifying peak flow reductions throughout the watershed. Selected results were also input into the current HEC-2 model of the watershed to quantify the benefits of predicted flow reductions in lowering predicted maximum Cooksville Creek water surface elevations (WSEs).

Preliminary results indicate peak flows can be reduced to 127 m3/sec at Dundas Street for the 100 year storm with the addition of all proposed storage basins. This corresponds to a 39 percent reduction from the 207 m3/sec peak flow. For the August 2009 storm, the SWMHYMO model predicts that peak flow can be reduced from 235 m3/sec to 129 m3/sec at Dundas Street. HEC-2 model outputs predicted an average WSE decrease of 0.84 meters for the 100 year storm through inclusion of the storage basins.

It should be noted (reference should also be made to Section 6.2.1 of the main report) that sites 14 and 15, while included in this Technical Appendix, were dropped during the site selection process.

Model Development

The current version of the future land use Cooksville Creek SWMHYMO model implemented in the 2002 Cooksville Creek Flood Remediation Plan (ERWG 2002) was used as a base for this modeling effort. The 100 year storm was not modified from the current version of the model. The model was then modified to create a new file for the August 4, 2009 storm. The hyetograph for the August 2009 storm was created from data provided in the 2009 Cooksville Creek August 2009 Flooding report for Mississauga rainfall recording station six (EWRG 2010). This station recorded the greatest 60 minute rainfall depth of the ten stations cited in the report. The timestep throughout the model had to be altered for the August 2009 storm because the Mississauga recording stations measured rainfall at 5 minute intervals, instead of the 10 minute intervals used for the 100 year storm.

Although the magnitude of the August 2009 storm peak rainfall intensity was less than that of the 100 year storm, the rainfall intensities in the time intervals leading up to the peak were greater in the August 2009 storm (Figure 1). In addition, the station six hyetograph was applied over the entire Cooksville Creek watershed in the SWMHYMO model, when in reality it only fell over a portion of the watershed. This resulted in higher peak flows in Cooksville Creek from the August

Aquafor Beech Ltd. Ref: 65109 B2 Cooksville Creek Flood Evaluation July 2012 Master Plan EA

2009 storm than the 100 year storm for a number of locations in the watershed (Table 1).The model was then modified to include the fifteen storage basins.

The location, size and drainage area information for each potential storage basin used in this assessment was first developed by Aquafor Beech. Locations of the fifteen sites of interest are included in Figure 2. Delineated storage basin drainage areas were cross referenced with a provided Cooksville Creek watershed map delineated with major roads and the sub basins as defined in the SWMHYMO model. The storage basins were then inserted into the model using the route reservoir command. Two sub basins as defined in the SWMHYMO model included multiple storage basins. Storage basins 3, 4, and 5 are in the same sub basin and so were lumped into one route reservoir command with an equivalent total capacity for this analysis. Storage basins 10, 11, and 16 were also lumped in similar manner. Figure 3 shows the updated schematic for the Cooksville Creek SWMHYMO model with these storage basin additions included.

To most effectively reduce the peak flow from each sub basin, route reservoir outflow-storage relationships were developed such that an outflow rate small enough to reduce the peak predicted flow rate for the sub basin but large enough to reserve storage basin capacity for the largest predicted flows in the sub basin. If a storage basin filled before the inflow peak arrived at the basin, then offline storage would not be available to capture a portion of the peak flow and the storage volume would not be used effectively. In short, storage basin overflow curves were developed to balance the need to reserve capacity to capture the peak of the storm while minimizing the peak flow rate delivered to the creek.

To accomplish this goal, the outflow-storage curves were adjusted such that a storage basin begins storing runoff only when the inflow rate is greater than a certain percentage of the 100 year peak inflow. This percentage is unique for each storage basin and depends on the characteristics of the sub basin and the storage basin size and location. Each outflow-storage curve was refined using an iterative method in which the storage basin curves were adjusted based on previous trial results. In some cases, the storage basin outflow rate could be lowered while still preventing the storage basin from filling before the inflow peak occurred. In other cases, the storage basins filled before the peak inflow occurred, so the outflow rate was raised to pass a larger percentage of the pre-peak flow while still capturing the inflow peak. An example of an outflow-storage curve used for storage basin 2 is shown in Figure 4.

A final adjustment to the SWMHYMO model involved reducing the timestep used to calculate outflow hydrographs from the storage basins. This was necessary because too large a timestep caused flow pulsing from the storage basins during the falling limb of the outflow hydrographs.

Results

SWMHYMO model results for the original storms and most recent analyses are summarized in Table 1. Peak flows through channels downstream of the storage basins were reduced to 61-70

Aquafor Beech Ltd. Ref: 65109 B3 Cooksville Creek Flood Evaluation July 2012 Master Plan EA percent of the 100 year storm peak and 55-67 percent of the August 2009 storm peak. The maximum peak flow discharged from the sub basins where storage basins were implemented ranged from 5 to 50 percent of the 100 year storm. A large area of the Cooksville Creek watershed remains unaffected by installation of the proposed storage basins. Particularly, runoff from sub basins CC1, CC2, CC3, CC4, CC5, CC8, CC9, CC10, CC11, CCWT1, and CCEB1 is not directed to a stormwater control.

Peak flow rates from the SWMHYMO model output at 15 locations were then input into the HEC-2 model using the original and storage basin-updated 100 year storm flow rates. Initial results indicate a decrease in the water surface elevation ranging from 0.03 to 2.61 meters with an average decrease of 0.84 meters (Figure 5a, Figure 5b).

References

Environmental Water Resources Group (EWRG). 2002. Cooksville Creek Flood Remediation Plan. May.

Environmental Water Resources Group (EWRG). 2010. Cooksville Creek Flooding August 2009. September

180 160 140 120 August 4, 2009 100 80 100 year 60 40

R a i n fa ll I t ens ty ( m/ h r) 20 0 0 .0 0 .5 1 .0 1 .5 2 .0 2 .5 3 .0 3 .5 4 .0 4 .5 5 .0 5 .5 6 .0 6 .5 7 .0 7 .5 8 .0 8 .5 9 .0 9 .5 1 0 .0 1 0 .5 1 .0 1 .5 1 2 .0 1 2 .5 1 3 .0 1 3 .5 1 4 .0 1 4 .5 1 5 .0 1 5 .5 Time (hours)

Figure 1. Hyetographs for the 100 year storm and August 4, 2009 storm (EWRG 2010).

Aquafor Beech Ltd. Ref: 65109 B4 Cooksville Creek Flood Evaluation July 2012 Master Plan EA

Table 1. Cooksville Creek SWMHYMO Results for 100 year and August 2009 storms

100 year storm August 2009 storm

Route Reservoirs Route Reservoirs Original Original Location for Basins 1-16 for Basins 1-16

% of % of m3/sec m3/sec m3/sec m3/sec original original

Site 14 7.4 0.4 5.4% 7.0 0.4 5.7%

Site 15 20.4 3.1 15.5% 19.1 3.2 16.6%

Site 1 62.0 9.4 15.1% 67.4 9.4 13.9%

Site 2 30.9 6.3 20.3% 27.2 17.8 65.2%

Site 3+4+5 29.8 6.1 20.3% 30.7 6.1 19.7%

Site 6 29.6 13.4 45.3% 27.0 22.8 84.3%

Site 7 42.0 16.9 40.2% 40.7 33.7 83.0%

Site 12 9.4 4.3 45.8% 8.2 9.3 113.3%

Site 8 57.6 23.1 40.1% 60.5 29.3 48.4%

Site 9 33.2 16.7 50.3% 35.3 33.1 93.7%

Site 10+11+16 43.3 8.8 20.2% 44.0 8.8 19.9%

After Route CC5 (Dundas St) 207.3 126.6 61.1% 234.5 129.1 55.1%

After Route CC4 (QW West) 210.1 131.8 62.7% 220.4 131.4 59.6%

After Route CC3 (QEW) 203.4 131.1 64.5% 208.1 127.0 61.0%

After Route CC2 (CNR) 196.9 130.1 66.1% 196.7 123.2 62.6%

After Route CC1 (Lakeshore Rd) 220.2 154.5 70.2% 217.3 145.2 66.8%

Lake Ontario 220.9 155.2 70.3% 217.5 145.4 66.8%

Aquafor Beech Ltd. Ref: 65109 B5 Cooksville Creek Flood Evaluation July 2012 Master Plan EA

Figure 2. Overall map showing locations of storage basins (obtained from Aquafor Beech, 7/13/2011)

Aquafor Beech Ltd. Ref: 65109 B6 Cooksville Creek Flood Evaluation July 2012 Master Plan EA

Figure 3. Modified Cooksville Creek SWMHYMO Computation Schematic

Aquafor Beech Ltd. Ref: 65109 B7 Cooksville Creek Flood Evaluation July 2012 Master Plan EA

100 Storage Basin 2

20 O u tf l o w ( % f 1 0 ye a r p e ak) 0 020406080100 Storage in Basin (% of maximum) Figure 4. Outflow-Storage Curve for Storage Basin 2

140

130

120

110

100

100 yr pre-storage E l e v a t i on ( m) 100 yr w/ storage 90 Minimum Elevation 80

70 8 7 6 5 4 3 2 1 0 Distance (km)

Figure 5a. Water surface elevations for the pre- and post-100 year storm updated files

Aquafor Beech Ltd. Ref: 65109 B8 Cooksville Creek Flood Evaluation July 2012 Master Plan EA

2.5

1.5

1 D e c r a s i n E l v t on ( m)

0.5

0 14 12 10 8 6 4 2 0 Distance (km)

Figure 5b. Decrease in water surface elevations for the 100 year storm by addition of storage basins

Aquafor Beech Ltd. Ref: 65109 B9 Cooksville Creek Flood Evaluation July 2012 Master Plan EA

APPENDIX C

Public Consultation Material

Aquafor Beech Ltd. Ref: 65109 C1 Cooksville Creek Flood Evaluation July 2012 Master Plan EA

Notice of Study Commencement and Public Information Centre

Aquafor Beech Ltd. Ref: 65109 C2 ÝÑÎÐÑÎßÌ×ÑÒ ÑÚ ÌØÛ Ý×ÌÇ ÑÚ Ó×ÍÍ×ÍÍßËÙß ÝÔßÍÍ ÛÒÊ×ÎÑÒÓÛÒÌßÔ ßÍÍÛÍÍÓÛÒÌ ÓßÍÌÛÎ ÐÔßÒ ÝÑÑÕÍÊ×ÔÔÛ ÚÔÑÑÜ ÛÊßÔËßÌ×ÑÒ ÍÌËÜÇ

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Public Information Centre Presentation Boards

Aquafor Beech Ltd. Ref: 65109 C3 CityofMississauga:FloodControlEvaluationStudy-MunicipalClassEA

Welcome Thecurrentstudyisbeingundertakenasa floodcontrolMunicipalClassEnvironmental TheCityofMississaugaisundertakinga Assessment(EA)withastudyarea FloodEvaluationStudyonCooksville extendingfromHighway401toLake Creek.Thestudyisbeingcompletedasa Ontario.ThroughtheEAprocess, MunicipalClassEnvironmentalAssessment alternativeshavebeendevelopedto andthestudyareaisshowninthefigureto addressthefloodpronesiteswhichhave theright. beenidentified.TheEAprocessprovides anopportunityforthepublictooffer commentsandinsighttothestudy,andto Background discussrelatedconcernswiththestudy team. TheCooksvilleCreekwatershedhasan areaofabout34km2 withitsheadwaters originatingnorthofHighway401.The ObjectivesofTonight’s watercourseflowstothesouthanddrains Meeting toLakeOntario.Thewatershedislongand narrowandisfullydevelopedwiththe Theobjectivesoftonight'smeetingareto exceptionofafewvacantparcelsofland. presenttheidentifiedproblemsand alternativesolutionsandtoprovidean CooksvilleCreekexhibitsvaryingconditions opportunitytothepublictoreviewthis throughoutitslength,rangingfromanatural materialandprovideinput.Attendeesare statetosignificantportionswhichhave askedtofilloutthequestionnaireprovided undergonesomedegreeofchannelization. tohelpestablishpublicacceptanceofeach ofthealternatives. Numeroushomesandpropertieshave floodedovertheyears,mostnotablyon ObjectivesoftheStudy August4,2009.Itisestimatedthat approximately120buildingswouldfloodfor Theobjectivesofthestudyareasfollows: the100yearstormandapproximately300 buildingswouldfloodfortheRegionalstorm PrimaryObjective: (HurricaneHazel). ·Reduceoccurrenceofriverinefloodingfor dwellingsandpropertiesadjacentto CooksvilleCreekalsohasaconsiderable CooksvilleCreek historyoferosionproblemsalongthe watercourse.TheCityhasspent SecondaryObjectives: approximately$8millionsincethemid ·Reduceextentandfrequencyoferosion 1990'storemediateerosionproblems. Therearealsootherissuesrelatedto ·Improvewaterqualityconditionswithin degradedwaterquality,lackofbaseflow CooksvilleCreek andaquaticresources. ·Improveaquatichabitatconditions CityofMississauga:FloodControlEvaluationStudy-MunicipalClassEA

ProblemandOpportunityIdentification

PROBLEMS OPPORTUNITIES

Flooding · Reductioninfloodingcouldoccurasa ·Approximately300dwellingsare resultofexpandingthecapacityof locatedwithintheRegulatoryfloodline. existingculvertsorbridges,reducing ·Floodingofdwellingshasoccurred theamountofflowgettingintothe severaltimes,mostrecentlyasaresult streamand/orexpandingthecapacity oftheAugust4,2009storm. ofthefloodplain.

Erosion · Someoftheabovemeasurescouldbe · Cityhasundertakenrestorationworks usedtoreduceerosionproblems, at12sitesoverthepast20years. improvewaterqualityconditionsand · Approximately10priorityerosionsites improveaquatichabitatconditions. remain.

WaterQuality · Existingwaterqualityconditionsare suchthatProvincialWaterQuality Objectivesarenotmetamajorityof thetime.Thisresultsinlossof aquaticlifeanddegradationof aestheticconditions.

AquaticResources · Onlytolerantfishspeciesresideinthe creekasaresultofdegradedwater quality,poorhabitatconditionsand instreambarriers. CityofMississauga:FloodControlEvaluationStudy-MunicipalClassEA

ExistingEnvironmentalConditions

Theexistingenvironmentalconditions withinthestudyareaaresummarized below.

Flooding TerrestrialHabitat

·Atotalof300dwellingsarelocated · Theterrestrialhabitatalongthestream withintheRegulatoryfoodline.As corridorgenerallyconsistsofmanicured notedintheaccompanyingfigurea propertiesoranarrowbandofculturally majorityofthefloodsusceptiblehomes influencedandheavilydisturbed arelocateddownstreamof riparianwoodland. BurnhamthorpeRoad. ·Thereareapproximately12Natural ·Theareamostsusceptibletofloodingis Areas(wetlands,woodlands)located locatedbetweenBurnhamthorpeRoad withinthewatershed. andDundasStreet.Dwellingsinthe KingStreetandPaisleyBoulevardarea Infrastructure couldexperiencefloodingevery5-10 years,onaverage. · Asanitarytrunksewerrunsadjacentto CooksvilleCreekinthelowerreaches. Erosion Attimes,thesewerormanholeshave beenexposedasaresultofstream · CooksvilleCreekhasexperienced erosion. significanterosionoverthelast20 yearsasaresultofurbanization,lackof stormwatermanagementmeasuresand theuniquecharacteristicsofthestream whichconsistsofshaleandlimestone inthelowerreaches.

Fishery

· Generally,therearepoorquality habitatsalongCooksvilleCreekdueto unstablesubstrates,lackofinstream coverandextremevariationinflows fromdrytowetweatherperiods.

· Afewwarmwaterfishspeciesthat toleratepoorwaterqualityconditions havebeenidentified. TowCintyofoOfMakvillississae-Fouguar:tFeelonoMdilCeonCtrreeolkEReacvaluahti2onStSatbudiliyza-tMiounnaicindpaRleClashabilistEAation

EnvironmentalAssessmentProcess Backgrounddata collectionand Manyprojectsrelatedtomunicipalsystemsaresimilarinnature,are interpretation carriedoutroutinely,andhavepredictableandmitigatable environmentaleffectswhichareinvestigatedaccordingtothe MunicipalEngineersAssociation“MunicipalClassEnvironmental Assessment”(October2000,asamendedin2007). Identificationofthe Thisstudyisbeingcarriedoutaccordingtotherequirementsofa problemsand MasterPlan.Theflowcharttotherightillustratesthekeystepstobe opportunities undertakenaspartoftheEAProcess.

Determinationof existingconditions

Developmentofa longlistof alternatives PublicInformation Centre1 May1,2012 Formulationand evaluationof strategies

Selectionof preferredstrategy CityofMississauga:FloodControlEvaluationStudy-MunicipalClassEA

DevelopmentofaLongListofAlternatives Thelonglistofalternativesthatweredevelopedmaybedividedintotwogeneralcategories(TraditionalandNonTraditional).Eachalternativewasassessedbased oncriteria(seeaccompanyingtable)consistentwiththeEnvironmentalAssessmentProcess.Thealternativeswhichreceivedafavourableratingwerebrought forwardandwillformthebasisofthePreferredStrategy.Eachofthealternativesthatwereconsideredaredescribedbelow.

TRADITIONALALTERNATIVES

WatercourseCapacityEnlargement CrossingCapacityEnlargement Ÿ Increasingthecapacityoftheexisting Ÿ Increasingthecapacityofexisting watercoursemayreducefloodlevels. culvertsorbridgesmayreducewater levels.

BeforeAfter BeforeAfter

Dykes/Berms FloodProofing LandAcquisition Ÿ Dykesorbermsarebuiltadjacentto Ÿ Landownerscanfloodproofbuildings Ÿ Floodsusceptiblepropertiescouldbe dwellingsinordertocontainflows bysealingorfillinginopeningswhich purchasedbytheCityorCreditValley withinthefloodplain. aresusceptibletoflooding. Conservationandthenremoved.

Before After CityofMississauga:FloodControlEvaluationStudy-MunicipalClassEA

NONTRADITIONALALTERNATIVES

StorageinUpstreamLocations SourceControlMeasures Ÿ Storageinupstreamlandswithinparks Ÿ Thesemeasures,whichareimplementedonprivate orvacantpropertiescouldbeusedto property,includeroofdownspoutdisconnection,use reducefloodlevelsinCooksvilleCreek. ofrainbarrels,perviousdrivewaysandraingardens.

In-ChannelStorage ConveyanceControlMeasures Tunnel Ÿ StoragewithinCooksvilleCreekcould Ÿ Thesemeasures,whichareimplementedwithinthe Ÿ Constructionofatunnel,whichwould beusedtoreducefloodlevels. municipalright-of-waymayincludebioretentionunitsor divertflowsabovelevelswhichcause perforatedpipes.Themeasuresencourageinfiltration floodingcouldbeconsidered. orevapotranspiration,therebyreducingrunoffand floodlevels. CityofMississauga:FloodControlEvaluationStudy-MunicipalClassEA

DescriptionoftheNaturalEnvironmentalCriteriaUsedfor DescriptionofSocial/CulturalCriteriausedfortheSelectionof SelectingthePreferredCriteria thePreferredAlternatives EvaluationCriteriaDescriptionofCriteria EvaluationCriteriaDescriptionofCriteria PotentialtoReduceRiverine · PotentialtoreducefloodingofpropertiesalongCooksvilleCreek Aesthetics/Recreation · Potentialforthealternativetobeanassettothecommunityby Flooding floodplain integratingthealternativeintoexistingsiteactivities(walking, PotentialtoReduceErosion · PotentialtoreduceerosionwithinCooksvilleCreek jogging,parkusage)and/orimproveaesthetics;ortoimpact existingparkusageordetractfromaesthetics PotentialtoImproveWater · Potentialtoimprovewaterqualitybasedonexistingwater Quality qualityconditions CompatibilitywithAdjacent · Therearepotentialimpactsassociatedwithconstructionof LandUse retrofitfacilities,orfuturemaintenanceparticularlywith PotentialtoImproveAquatic · Potentialtoimproveaquatichabitatsbyimprovingbaseflows, respecttoadjacentlanduse Habitat orstreamhabitat · Access/egressalsoneedstobeconsidered CommunityDisruption · Thepotentialofthealternativetodisruptthecommunity,more specificallygiventhesurroundinglanduse–businessactivities during,oraftertheconstructionprocess Public/UserAcceptance · Public/useracceptabilityofproposedalternativeincluding constructionimpacts,propertyvalue,lifestylechanges, noise/odourissues

DescriptionoftheEconomicCriteriaUsedforSelectingthe DescriptionofImplementationCriteriausedfortheSelectionof PreferredAlternatives thePreferredAlternatives EvaluationCriteriaDescriptionofCriteria EvaluationCriteriaDescriptionofCriteria ConstructionCosts · Therelativecostofthealternative TimingtoImplement · Lengthoftimerequiredtoimplementtheproposedalternative OperationandMaintenance · Therelativecostofoperatingandmaintainingthealternative TechnicalFeasibility · Thefeasibilityofimplementingtheproposedalternative basedonfactorssuchasoverallmaintenancefrequencyand intensity,equipmentneedsandfuturepermitrequirement InfrastructureProtection · Potentialtoprotectexistingorproposedinfrastructure includingstormoutfalls,sanitarysewers,pedestrianbridges, etc. CityofMississauga:FloodControlEvaluationStudy-MunicipalClassEA

EvaluationMatrixforTraditionalAlternatives WatercourseCapacity CrossingCapacity EvaluationCriteria Dykes/Berms FloodProofing LandAcquisition Enlargement Enlargement · Goodpotentialto · Goodpotentialto · Moderatepotentialto · Limitedpotentialto · Limitedpotentialto NaturalEnvironment reduceriverine reduceriverine reduceriverine reduceriverine reduceriverine flooding flooding flooding flooding flooding · Lowtomoderate · Lowtomoderate · Moderate · Moderate · Moderatetohigh constructioncost constructioncost constructioncost constructioncost constructioncost Economic · Moderatetohigh · Moderatetohigh · Lowoperationand · Lowoperationand · Lowoperationand operationand operationand maintenancecost maintenancecost maintenancecost maintenancecost maintenancecost · Generallyaccepted byagencies,maybe · Generallyaccepted · Generallyaccepted issueifconstructed bypublicand bypublicand · Generallyaccepted · Lastresortalternative onprivateproperty agencies agencies byagencies byagencies · Limiteddisruption Social/Cultural · Limiteddisruption · Limiteddisruption · Acceptanceby · Generallydoesnot duringconstruction duringconstruction duringconstruction homeownerssite meetwithlandowner · Compatibilitywith · Compatiblewith · Compatiblewith specific approval adjacentlandusesto adjacentlanduses adjacentlanduses beassessedonsiteby sitebasis · Feasibilitydependent · Technicallyfeasible · Technicallyfeasible · Technicallyfeasible · Technicallyfeasible uponsiteconditions · Moderate · Moderate Technical · Shortimplementation · Shortimplementation andfloodingextent implementation implementation period period · Shortimplementation period period period

OverallAlternative Rank

· Notbroughtforward, · Broughtforward,but buttobe limitedtopublic · Notbroughtforward Comment · Broughtforward · Broughtforward implemented landsorwith exceptforvacant independentlyby homeownerconsent properties homeowner CityofMississauga:FloodControlEvaluationStudy-MunicipalClassEA

EvaluationMatrixforNonTraditionalAlternatives

StorageinUpstream SourceControl ConveyanceControl EvaluationCriteria In-channelStorage Tunnel Locations Measures Measures · Goodpotentialto · Goodpotentialto · Goodpotentialto reduceriverine reduceriverine reduceriverine · Moderatepotentialto flooding,limitedfor flooding,limitedfor flooding,limitedfor reduceriverine · Goodpotentialto basementflooding basementflooding basementflooding NaturalEnvironment flooding reduceriverine · Goodpotentialfor · Goodpotentialfor · Goodpotentialfor · Moderatepotentialto flooding reducingerosion, reducingerosion, reducingerosion, reduceerosion improvingwater improvingwater improvingwater qualityandaquatics qualityandaquatics qualityandaquatics · Moderate · Lowconstructioncost · Moderate constructioncost · Lowtomoderate constructioncost · Moderateoperation · Moderate operationand · Moderateoperation · Highconstruction andmaintenancecost constructioncost maintenancecost andmaintenancecost cost Economic · Moderatebenefitin · Moderateoperation · Moderatebenefitin · Moderatebenefitin · Highoperationand protectingexisting andmaintenancecost protectingexisting protectingexisting maintenancecost infrastructurewithin infrastructurewithin infrastructurewithin floodplain floodplain floodplain · Generallyaccepted · Generallyaccepted · Generallyaccepted · Generallyaccepted · Compatibilitywith bypublicand bypublicand bypublicand bypublicand adjacentlanduses agencies agencies agencies agencies unknown Social/Cultural · Lowtomoderate · Lowtomoderate · Lowcommunity · Lowcommunity · Questionableagency communitydisruption communitydisruption disruption disruption acceptance · Potentialtobean · Potentialtobean · Potentialtobean · Potentialtobean · Considerable assettocommunity assettocommunity assettocommunity assettocommunity communitydisruption · Feasibilitydependent · Technicallyfeasible · Technicallyfeasible · Feasibilitydependent onsiteconditions · Technicallyfeasible · Shorttomoderate · Shorttomoderate uponsiteconditions Technical · Shorttomoderate · Shortimplementation implementation implementation · Longimplementation implementation period period period period period

OverallAlternative Rank

· Broughtforward,but · Broughtforward,but tobeimplementedas tobeimplementedas Comment · BroughtForward · BroughtForward partofCityWide partofCityWide · NotbroughtForward WaterQualityStudy WaterQualityStudy Implementation Implementation CityofMississauga:FloodControlEvaluationStudy-MunicipalClassEA

DescriptionofthePreferredStrategy Thealternativesthatreceivedafavourableratingwerebrought forwardandwillformthebasisofthePreferredStrategy.A descriptionofthePreferredStrategyisprovidedbelow.

DescriptionofthePreferredStrategy

ThePreferredStrategyinvolvesacombinationof: Ÿ Storageinupstreamlocationstoreduceflowswithin CooksvilleCreektoacceptablelevels. Ÿ Watercourseandchannelcapacityenlargementstogether withcreationofabermintheKingStreetandPaisleyRoad areaswherehomesaremoresusceptible. Ÿ ConstructionofabermadjacenttoCooksvilleCreekto protecthomesalongRhondaValley. Ÿ Implementationofsourceandconveyancecontrolmeasures (tobeconsideredaspartoftheCityWaterQualityStrategy UpdateStudy).

Benefits

Ÿ Collectively,implementationoftheabovemeasureswill providefloodprotectionforallpropertiesforthe100year storm. Ÿ Issuesrelatedtoongoingerosion,degradedwaterquality andpooraquatichabitatconditionswillalsobeimproved. CityofMississauga:FloodControlEvaluationStudy-MunicipalClassEA

PREFERREDSTRATEGYCOMPONENTS: WatercourseCrossingandChannelImprovements

PaisleyBoulevard

Before

After

KingStreet

Before

After CityofMississauga:FloodControlEvaluationStudy-MunicipalClassEA

PREFERREDSTRATEGYCOMPONENTS: Storage

EastgatePark

PotentialAreasWhereStorage CouldbeImplemented

TypeNumber

ExistingParks9

VacantLand2

HydroCorridor2

ConceptualImageof Sites UndergroundStorage

1.Site3176.FrankMcKechnie 11.McKenziePark Park

2.OfflineBritannia 7.EastgatePark12.HuronHeights Farm Park317

3.GreyshalePark8.HydroCorridor- 13.GivenRoad East

4.HeritageHills 9.Adjacentto Park Metro(food)

5.HydroCorridor- 10.CentralParkway West East

Atotalof13potentialsiteshavebeen identified.Allbutoneofthesesiteswould involvetheconstructionofunderground facilitiestoreducepeakflowsanderosion, improvewaterqualityandincreaseflows duringdryperiods. CityofMississauga:FloodControlEvaluationStudy-MunicipalClassEA

PREFERREDSTRATEGYCOMPONENTS: ConstructionofBerm

RhondaValley CityofMississauga:FloodControlEvaluationStudy-MunicipalClassEA

Thankyouforyourparticipation! Foradditionalinformation,pleasecontactoneofthe studyteammembers: NextSteps Mr.MuneefAhmad Aftertonight’smeeting,wewillundertakethefollowingSteps: WaterResourcesEngineer Ÿ Gatheryourcomments CityofMississauga Ÿ Reviewfeedback 201CityCentreDrive,Ste800 Ÿ Finalizealternativeranking Mississauga,ONL5B2T4 Ÿ Prepareconceptualdesignsforthepreferredstrategycomponents Phone:9056153200ext.4793 Ÿ CompletetheEAdocument E-mail:[email protected] Ÿ PrepareanoticeofcompletionandhavetheEAdocumentavailableforreview Mr.DaveMaunder SeniorProjectManager AquaforBeechLimited Consultant SkymarkAvenue,Ste202,Bldg6 Mississauga,ONL4W5B2 Phone:9056290099ext.290 Email:[email protected] Cooksville Creek Flood Evaluation July 2012 Master Plan EA

Aquafor Beech Ltd. Ref: 65109 C4