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Rehana Rajabali Presentation - Flood Risk Management and Toronto Islands 06.21.19Full Spectrum Flood Risk Management TRCA activities to manage riverine and lake -based flood risk Presented by: Rehana Rajabali Senior Manager, Flood Risk Management June 21, 2019 Toronto and Region Conservation Authority Presentation Outline Riverine Flood Risk Management • The nature of flood risk in our region • Flood risk management approaches and activities • New tools and industry thought leadership Toronto Islands Flood Risk and Mitigation • Overview of Island flooding — 2017 and 2019 • Highlights from Flood Mitigation Report The information contained in this presentation is copyright © Toronto and Region Conservation Authority Toronto and Region Conservation Authority 2 Riverine flood `'risk in T jurisrcfioOWN5X1OFV%ep�" �� Is x � S�' N 37.1 DURHAM RE ION 21-3 \� _J� DI/FFINS YO EGION CREEK I Hectares of floodplain °N F R" , ER= H' RIV-R RFUTHK Flood -Vulnerable ClustersPEREFRE „gJ "251 0 RIVERP ', i„ ` Faervc"xrarvs RIVER Residents affected in \t.I ` "r DAV ,48 2'-a 3e-129 27 the Regulatory storm event 94 g �U3os �s°-s DON Employees affected in "�. R'°E" '"'CGHLAND REEK CREEK the Regulatory storm event NOF PEEL s 13 -0 4 11-0 Buildings affected in the /27.2 e CITY OF TORONTO Regulatory storm event 6 U 35-9 \CIHEEEKIK )3 I a C 26< of Impassible road , %rTOIRCOKE segments in the Regulatory storm °,-, 111 2 21-1 �.: •... Toronto and Region�101 \ Conservation tD Autnori =- Flooding can happen any time of year Summer • Thunderstorms with significant rainfall — within a short period of time, intense localized downpours from thunderstorms can produce flash flooding. Spring • Spring freshet — accumulation of snow during the winter season can lead to flooding during the early spring, if conditions are right. When temperatures rise, snow melts and turns to runoff. Fall • Seasonal weather systems — large wet weather such as tropical storms, can last several days. Prolonged and heavy precipitation on top of already saturated soils causes rivers to rise. Winter • Ice jams — when a rise in water level or a thaw in the ice breaks into large chunks, these chunks can become jammed at bridges or other obstructions. The rise will become backed up and can overflow its banks. Riverine Flooding is the partial or complete inundation of the floodplain, caused by bank overtopping when the conveyance capacity of rivers and streams is exceeded. It falls under the mandate of Conservation Authorities. Urban flooding is the inundation of a built environment, caused by rainfall overwhelming the capacity of drainage systems, such as storm sewers and roads. Also called pluvial flooding, it falls under the mandate of municipalities. 5 Who deals with floods? • Federal and provincial governments: Funding, policy guidance, MNRF direct responsibilities, weather warnings —� • Conservation Authorities: Land -use, permitting, flood forecasting and warning (as delegated from the province), F4 etc. Municipalities: Primary emergency response, Management and Civil responsibility for all types of - including flooding (under Emergency Protection Act); storm drainage infrastructure and urban (pluvial) flooding Individuals: Personal preparedness and property -level measures Insurance: Financial risk mitigation Toronto and Region Conservation Authority 6 PREVENTION & MITIGATION Limiting exposure to risk: • Implementing TRCKs regulations and policies Reducing risk: • Operating a flood forecasting and warning program Maintaining flood control infrastructure • Creating a flood protection strategy for vulnerable areas • Implementing remedial works projects Understanding the risks: • Climate, geology, watershed response and potential for climate change Documenting the risks: • Floodplain mapping, identification of flood vulerable areas RECOVERY • Flood event documentation and lessons learned Storm analysis No silver bullets... PREVENTIC & MITIGATIC RECOVEF PREPAREDNESS • TRCXs Flood Contingency Plan • Emergency Plans • Emergency Operations Centre Training ZEPAREDNESS • Public Education RESPONSE • Provide Flood Forecasting and SPONSE Warning (issuing flood messages) • Operate flood control infrastructure • Communicate information and advice • Data management ... but many bronze ones 7 tion and tion • Floodplain mapping and the engineering studies that support it • Hydrology • Hydraulics • Flood Risk Assessment • Land Use Management • Stormwater Management • Living City Policies • Flood Control Infrastructure • e.g. G. Ross Lord Dam • Capital works for flood protection • e.g. Port Lands Flood Protection Toronto and Region Conservation Authority Flood Risk Assessment and Ranking Project Toronto and Region Conservation Authority Flood Risk Assessment and Ranking Project NXIM N IIIIIIIII Special Policy Areas Flood -Vulnerable Clusters 1. Rockcliffe 2. Jane -Wilson 3. Dixie -Dundas 4. Pickering Village 5. Bolton Core 6. Avondale/Spring Creek 7. Progress Business Park 8. Lower Don 9. Lake Wilcox 10. Markham Industrial (Don Mills Ditch) i Conservation Authority 10 Preparedness • Emergency Management Planning • Flood Contingency Plan • Municipal emergency plans • IMS structure • Training • Flood Duty Officer training • IMS training • Partnership with municipalities • Public Education • Emergency Preparedness Week • Flood preparedness curriculum partnership with Education • Flood Risk Outreach Strategy • Floodplain information on the web Toronto and Region Conservation Authority 11 Flood Response Conservation Authorities Monitor watershed and weather conditions and operate a flood forecasting and warning system Issue Flood Messages Operate Conservation Authority dams and flood control structures Provide technical advice to municipalities Maintain communications with municipalities and other agencies Municipal Role Notify appropriate municipal officials, departments and agencies. Determine the appropriate response and deploy municipal resources to protect life and property. If required, declare a flood emergency and implement their emergency response plan. Request provincial assistance if needed Toronto and Region conservation Authority 12 TRCA Flood Message Types Watershed Conditions High flows, unsafe banks, melting ice or other factors that could be Statement - Water Safety dangerous for recreational users such as anglers, canoeists, hikers, Jim" L children, pets, etc. Flooding is not expected. Watershed Conditions Early notice of the potential for flooding based on weather forecasts calling Statement - Flood Outlook for heavy rain, snow melt, high wind or other conditions that could lead to high runoff, cause ice jams, lakeshore flooding or erosion. Flood Flooding is possible in specific watercourses or municipalities. aWatchmi Municipalities, emergency services and individual landowners in flood- I prone areas should prepare. — I : W� V, nil Y Flooding is imminent or already occurring in specific watercourses or municipalities. A notice that critical high water levels and waves are imminent and/or occurring, which could result in shoreline flooding and/or erosion Flood Risk Outreach Program and Site - Specific Flood Response Plans Flood Plain Map Viewer I NCGIS Wadd Genwding Sem - -Z a Y Toronto and Region Conservation Authority 1 14 Focus efforts on priming audiences r No Lead Time Warnii DelayT Next Gen. Flood Forecasting Models Public Outreach to Flood Vulnerable Areas Site -Specific Flood Response Plans Toronto and Region Conservation Authority 1 15 TRCA Flood Monitoring (Gauging) Network I oronto and Region Conservation Authority 16 5 W ME- ✓ Watershed Boundaries Flood Plain Flood Vulnerable Area Dam Gauges ✓ Stream Gauges 7 Rain Gauges Weather Radar STATION MHP �Wum CE'Nm.uvr.. Preelpitadon Bars ,z - x�nwa ,,r EfOBICOKE CRAT BRAMPTON 28]&3623 ID WC26 210.170m 1inoA� MASaAMM ianonM 11.15AM ® EmmIoad TabularD=2a 1 st72h•;ur5) 211 HHA - W (2I3.SWO ) l p Wo l - WL 210.000m zm Mivtsssul ga�� sn�naw�Y _ Flood Forecasting Decision Support System •Ri�. J/?T � s _ 18 cn uw...nnm Ne. Ml.eue�ga m ,II Aull.px. \ Xnmibn '-m y. GPern+'Y� int w..i. xox�A%P [eMn wtllenu J •Ri�. J/?T � s _ 18 Recovery • Impact Tracking • Post -event analysis • Data collection • Lessons learned Toronto and Region Conservation Authority .jd .% Photo credit: Sean Tamblyn Toronto Islands Flooding and Mitigation Toronto and Region Conservation Authority 20 0 TRCA support for flood response (g LakeOmzno High Lae@ 2019 Y } E C i hqs:oa�isKt�.ocalnry+,waleneaeia a. tr "4n I Toronto Islands Flood Characterization and Risk Assessment Projed Flood M0iga0on Altemawes Report 4,Me911B I laN)101R3MN_F1WMkphn Long-term mitigation measures WARD'S ISLAND - OPTION 4 Bair TORONTO ISLANDS FLOOD AND RISK ASSESSMENT rwac2 �aiws aon,..�� x�m. �JOw�v� Aty 124 J'. Next Steps • Update Flood Characterization to account for this year's water levels • Sort recommendations into short-term, medium-term, and long-term, and confirm whatever additional studies may be required (ie: confirmatory soils studies, Environmental Assessments, etc.) • Work with City of Toronto to pursue DMAF and other funding sources and to move towards implementation of preferred solutions Toronto and Region Conservation Authority 126 Thank you Rehana Rajabali, P.Eng., MUDS Senior Manager, Flood Risk Management Development and Engineering Services Rehana.Raiabali(aD-trca.ca www.trca.ca www.trca.ca/flood @TRCA_Flood Toronto and Region Conservation Authority