StreamStream RestorationRestoration DesignDesign andand ManagementManagement inin CityCity ofof TorontoToronto (Highland Creek Watershed Case Study): Reactive,Reactive, ProactiveProactive && AdaptiveAdaptive ManagementManagement Presentation to the Latornel Conference: Session Climate Change etc November 18, 2015 William J Snodgrass, & Don Sorel Stream Restoration Specialists , Water Infrastructure Management, City of Toronto WWFMPWWFMPWWFMP PhilosophyPhilosophyPhilosophy • Wet weather flow issues to be managed on a watershed basis • Stormwater Management using a hierarchical approach: - Source Controls – lot level - Conveyance System – road right of way - End-of-pipe – before stormwater is discharged • Consider Source control measures first and balance them with the other measures in regards to effects on Environmental // Social // Economic Factors StrategiesStrategies && CostCost EstimatesEstimates Strat Description Cost No. [billion] 1 Status Quo accom., upstream growth and 1 + intensification in Toronto (1 million) 2 Opportunistic 3 3 Achieve moderate targets with aggressive 5 E O P 4 Achieve moderate targets – aggressive 6 source and conveyance controls 5 Achieve significant targets 11 GeomorphicGeomorphic && AquaticAquatic habitathabitat ResponseResponse (Don R trib.) TargetTarget ModerateModerate –– 8.58.5 SignificantSignificant -- 66 Peakiness [Qp/ Qb] 20 15 10 Series1 Peakiness 5 0 0123456 Strategy Numbber THETHE MASTERMASTER PLANPLAN (2003)(2003) • Master Plan defines the next steps needed to improve water quality and protect infrastructure • Preferred Strategy (Focus 70 – 100 a) • to achieve the ambitious goals of the plan (over 70 - 100 years) • 25 year Master Plan • a list of projects to be implemented over the next 25 years • considers priority areas for water qaimprovement a priorities - Health & Safety (beach water quality, basement flooding, river flooding) - Legislative (combined sewer overflow control: MOE F5-5) - Infrastructure Protection & Renewal - Accommodate Growth $40 million annually for 25 years (total, $1 billion) EXPENDITURESEXPENDITURES ININ CITYCITY--WIDEWIDE 2525 YEARYEAR PLANPLAN PUBLIC EDUCATION ($30 M ) - MUNICIPAL OPERATIONS ($52 M ) - SHORELINE MANAGEMENT ($44 M ) - SOURCE CONTROLS ($107 M ) - CONVEYANCE CONTROLS ($97 M ) END-OF-PIPE CONTROLS ($757 M ) BASEMENT FLOODING ($57 M ) STREAM RESTORATION ($122 M) WWFMPWWFMPWWFMP StreamStreamStream RestorationRestorationRestoration Proactive StreamStreamStream RestorationRestorationRestoration ProjectProjectProject Humber Creek - After Humber Creek - Before ImpactsImpactsImpacts ofofof AugustAugustAugust 19,19,19, 200520052005 StormStormStorm • 2-3 hour storm • exceeded 1 in 100 year storm in north part of the City – Highway 401 to Steeles Avenue corridor • City of Toronto rain gauge station recorded 153 millimetres AugustAugustAugust 191919 ––– 3:003:003:00 pmpmpm AugustAugustAugust 191919 ––– 3:303:303:30 pmpmpm AugustAugustAugust 191919 ––– 4:104:104:10 pmpmpm AugustAugustAugust 191919 ––– 4:304:304:30 pmpmpm AugustAugustAugust 191919 ––– 4:504:504:50 pmpmpm AugustAugustAugust 191919 ––– 5:105:105:10 pmpmpm AugustAugustAugust 191919 ––– 5:305:305:30 pmpmpm AugustAugustAugust 191919 ––– 5:505:505:50 pmpmpm AugustAugustAugust 191919 ––– 6:106:106:10 pmpmpm AugustAugustAugust 191919 ––– 6:306:306:30 pmpmpm AugustAugustAugust 191919 ––– 7:307:307:30 pmpmpm RainRainRain GaugeGaugeGauge DataDataData 153 148 83 S S 150 S 80 ´ 119 121 106 104 97 S S 95 S S S S S 94 72 S S T 36 50 T: 86 47 T T T 49 46 23 T : 39 31 : T 19 T : : : 32 35 T T T 35 AUGUST 19, 2005 : 31 35 T : STORM EVENT : T 35 : RAIN GAUG E LO CATION S : T T (August 19,2005- Storm Event) 1 Data Summary - Gauge Figure Rain T SH OW ING TO TA L RAIN (mm) 26 : AN D RETURN FRE Q UE NCY : T T Legend 38 To tal Ra in fall (m m ) T: ! RE TURN FREQ UENCY T: Und er 2yr sto rm T Und er 5yr sto rm T Und er 25yr storm S 100yr storm an d over Prepared B y: Water Infrastructure M anagem ent DamageDamageDamage SummarySummarySummary • Flash floods of creeks, rivers and ravines • Overflowed stream banks • Watercourse bank erosion • Damage to public and private infrastructure and property • Sewer Backups InsuranceInsuranceInsurance BureauBureauBureau ofofof CanadaCanadaCanada • most expensive natural disaster in Ontario history • expect to pay out more than $400 million • impact from Kitchener-Waterloo to Toronto to Durham & beyond • vast majority of claims for sewer back-ups Source: http://insurance-canada.ca/consinfohome/IBC-Ontario-storm-509.php Reactive; Emergency Situation DVP/Bayview Extension Roads were reopened overnight Military Trail @ Ellesmere MilitaryMilitaryMilitary TrailTrailTrail @@@ EllesmereEllesmereEllesmere RoadRoadRoad Saturday,Saturday,Saturday, AugustAugustAugust 20,20,20, 200520052005 MilitaryMilitaryMilitary TrailTrailTrail @@@ EllesmereEllesmereEllesmere RoadRoadRoad Opened Friday August 26 Finch @ Black Creek FinchFinchFinch @@@ BlackBlackBlack CreekCreekCreek 2 High Pressure Gas Mains Broken Watermain Broken Maintenance Hole Bell Canada Plant Bell Canada Plant Parks Path Toronto Hydro and Rogers Cable StreamStreamStream ErosionErosionErosion • Over 140 sites (Toronto Water, Parks & TRCA) were investigated to prioritize repairs • Damage ranged from fence damage to stream bank collapse • Multiple Reports on estimated costs and timelines • Lessons from May 2000 storm– took 4 - 5 years to repair ¾ of sites G. Ross Lord Park Black Creek Birkdale Ravine d d R R t m y a S e l h Highland Creek e k r m g i r a n o B M Y t Finch Ave S i l s e L Sheppard Ave t Derrydowns S e l e e Park K Birkdale Ravine Ellesmere Rd d t S R t e s Lawrence Ave r d i u s h g t n a i B n r o $ M e e Eglinton Ave v v A A k g n P i l Highland Creek a p i i r K o t Sewage Treatment c i V Plant Danforth Ave Bloor St Hanlan’s Point HighlandHighlandHighland CreekCreekCreek TrunkTrunkTrunk SanitarySanitarySanitary SewerSewerSewer CollapseCollapseCollapse • Summary of Actions – Isolated area discovered after creek flows subsided (Monday AM, August 22) – Agencies contacted and approval granted for emergency repair – With Toronto Public Health and Parks - Morningside Park closed for public health & safety concerns Reactive Management Ellesmere Rd Exposed Trunk Sanitary Sewer HighlandHighlandHighland CreekCreekCreek TrunkTrunkTrunk SanitarySanitarySanitary SewerSewerSewer RepairRepairRepair • Creek redirected and trench excavated to intercept the sanitary flows • Spill contained by Monday evening • Permanent repair of the trunk sewer underway • Determining most appropriate method of protection from further damage for this valley segment (i) DFO / MNR TRCA Permits (ii) GSMPs - The Long Term Planning Process! Valley Segment 4A Emergency Works Characterization Report Segment 4A Phase III Markham Road Bridge Valley Segment 8 At Progress Environmental Assessment Morningside Bridge Emergency Proposed Extension Works Phase I to 4A Study Area Phase I (Stage 2 & 3) Markham Road Bridge At Lawrence / West Highland Fish Passage Highland Creek Geomorphic Systems Master Plan Scarboro Golf Course West Highland Restoration State of Good Repair & Emergency Works • Response to May 12, 2000 and August 19, 2005 Storms, • Response to many other storms • Work Locations Dictated by Immediate Need • Design based on geomorphic principles • Guided by GSMP where completed Valley Segment 8 Valley Segment 8 – Current Conditions Phase IV Phase III Phase I Phase II TheTheThe ConceptConceptConcept PlanPlanPlan • Principles – Thalweig Based on Aug 19th storm – Channel and floodplane characteristics • Channel on edge – single vs braided • Channel width & floodplane extension • Stream Power and Erodable bottom • Narrow confined valley; multiple levels of evolution • Large mobile bars and sediment load – Move from a reactive mode to a holistic systems analysis – Lesson from 2002 storm rebuild mapped onto Aug 19th 2005 storm damage – City Conclusion, supported by agencies – completely Reconstruct Channel – Maintain channel depth to floodplain elevation geometry – Estimated riffle – pool geometry based on Regional Curves – Aggressive planting strategy for floodplain Reactive Management with Planning = Adaptive Exposed Trunk Sanitary Sewer VVV SSS 888 VVV SSS 888 SummerSummerSummer 200820082008 SummerSummerSummer 200820082008 VVV SSS 888 NovNovNov 200720072007 VVV SSS 888 OctOctOct 201520152015 TakeTakeTake homehomehome messagesmessagesmessages • Management – Asset Management – Proactive Management - WWFMP ; GSAHMP(Geomorphic Systems Aquatic Habitat Master Plan – Reactive Management (Basement Flooding; Stream Restoration, after major storms) – Adaptive Management • GSAHNP Enhancements – Coordination with Urban Valley Land Projects (Trails, Pedestrian bridges; Roadway Culverts and Bridges; washrooms etc) – Riparian Zones and Terrestrial Natural Heritage StreamStreamStream RestorationRestorationRestoration StudyStudyStudy /// M.P.M.P.M.P. (Planned(Planned(Planned ––– proactiveproactiveproactive management)management)management) Watershed Tributary Scale Geomorphic Scale Systems and Habitat MP) •WWFMP • Burke Brook • Highland • Newtonbrooke Creek GSMP • Taylor Massey Creek •Mud •Duncan • Wilket Proactive Management ManagementManagementManagement WWFMPWWFMPWWFMP --- StreamStreamStream RestorationRestorationRestoration (Planned(Planned(Planned ––– proactiveproactiveproactive management)management)management) StreamStreamStream RestorationRestorationRestoration OverallOverallOverall MapMapMap (TW(TW(TW &&& TRCA)TRCA)TRCA) AdaptiveAdaptiveAdaptive ManagementManagementManagement