Public Information Centre (PIC) February 12, 2020 Content Purpose - PowerPoint PPT Presentation

Tilbury Stormwater Master Plan Municipal Class Environmental Assessment Public Information Centre (PIC) February 12, 2020

Content Purpose of this PIC Project Team Study Area Master Plan Process Community Café Summary Stormwater Management in Tilbury Existing Conditions Assessment Proposed Design Alternatives Next Steps

Pur urpo pose of of t the he PI PIC  Provide a progress update for the study.  Discuss the challenges of stormwater conveyance in Tilbury.  Present the existing stormwater conveyance model results.  Present the design alternatives developed to address flooding in Tilbury.  Obtain feedback from residents regarding the design alternatives and solutions.  Break-out tables to discuss design alternatives after the presentation.

Proj ojec ect T Team eam Matthew Link Project Coordinator Chris Thibert Director, Engineering and Transportation Services Mark McFadden Manager, Infrastructure Services Jerry Corso Manager, Public Works South Katerina Oliver Drainage Superintendent Adam Spargo – ERI Project Manager Chris Moon – ERI Project Director and Senior Water Resources Engineer Brad Dickieson – ERI Water Resources EIT Stephen Jahns – RC Spencer Senior Engineer and Project Advisor Dennis McCready – RC Spencer Senior Drainage Engineer

Study udy Ar Area  The Community of Tilbury

Project Ba Background und Study Purpose  The purpose of the Stormwater Master Plan is to identify a set of alternatives to address various flooding issues in Tilbury. Phase 1 Phase 2 Problem or Opportunity Alternative Solutions Select Preferred Identify Problem or Existing Conditions Evaluate Alternative Solution Opportunity Flood Assessment Solutions – Identify Recommended Solution Public Consultation Identify Alternative Master Plan Report Community Cafe Solutions and Public Consultation Notice of Completion September 2019 PIC - Review Identify Impact of Alternative Solutions Solutions on the Public Consultation Natural, Social and 30-day Review Period WE ARE HERE Economic Environment and Mitigation Measures

Co Communi unity Ca Café S Sum ummary • 34 attendees signed in at the meeting. • 19 flooding questionnaires completed. • Key areas identified: • Lyon Street (1). • Odette Court (3). • Sunset Place / Thomas Crescent (5). • Laurentia Drive / Rose Avenue (8). 1 • Homestead Drive (3). • Key Flooding Concerns 1 3 4 4 • September 2018 Flood Event. 4 • Sump pumps and basement flooding. 3 • Laurentia Drive – Farm Tile Drains.

Co Communi unity Ca Café S Sum ummary • 34 attendees signed in at the meeting. • 19 flooding questionnaires completed. • Key areas identified: MORE • Lyon Street (1). • Odette Court (3). QUESTIONNAIRES • Sunset Place / Thomas Crescent (5). AVAILABLE • Laurentia Drive / Rose Avenue (8). 1 • Homestead Drive (3). TONIGHT • Key Flooding Concerns 1 3 4 4 • September 2018 Flood Event. 4 • Sump pumps and basement flooding. 3 • Laurentia Drive – Farm Tile Drains.

Stormwater Co Conveyanc nce  What is stormwater? Surface runoff after rainfall or snowmelt. Surface Runoff Surface Runoff Catchbasin Catchbasin Storm sewer

Stormwater Co Conveyanc nce  Stormwater: Surface runoff after rainfall or snowmelt.  Stormwater Collection System is made up of two components:  Minor System: Storm sewers convey small, frequent storms – Municipal design standard = 5-year storm event. Catchbasin Catchbasin Storm sewer

Stormwater Co Conveyanc nce  Stormwater: Surface runoff after rainfall or snowmelt.  Stormwater Collection System is made up of two components:  Minor System: Storm sewers convey small, frequent storms.  Major System: Roads and ditches convey larger, infrequent storms – 100-year storm event with max. depth of 0.3 m. Road Conveyance Catchbasin Catchbasin Storm sewer

Sep 2018 p 2018 Storm E Event  4 inches (100 mm) of rainfall in 1 hour.  In comparison a 100-year storm event equals 2 inches (52 mm) of rainfall in 1 hour. 100 mm 52 mm

Typi pical Stormwater Co Conveyanc nce 3 Major System along road Min. 1.2 m River / Creek 1 2 Storm sewer outfall Minor System in pipes

Challeng Cha nges i in T n Tilbur bury  Very flat topography constrains the stormwater conveyance system.  Minor system : Outlets to Trembley Creek and Mallot Drain. Shallow, channels limit the depth of the storm sewer system. Leads to flat storm sewers with reduced capacity.  Major System : Flat topography requires a saw toothed road profile to provide sufficient grade for drainage. This creates trapped low points along the road where ponding will occur. Saw Toothed Road Design 3 Trapped Low Points Major 1 System Shallow Outlet Minor 2 System Flat and Reverse Grade Storm Sewers

Private S Storm S Sewer Co Conne nnections ns Backflow Preventer Sump Pump connected to the Storm Sewer

Private S Storm S Sewer Co Conne nnections ns Storm sewer at capacity. Pressure head from road ponding

Private S Storm S Sewer Co Conne nnections ns Not outlet for sump pump. Basement flooding occurs.

Private S Storm S Sewer Co Conne nnections ns Direct sump pump to front yard to allow alternate outlet during storm events

Probl blem / O Oppo portuni unity  The flat topography and constrained outlets have led to a stormwater conveyance system that cannot convey the minor and major systems effectively.  Basement flooding and overland flooding has occurred in Tilbury.  Improvements to the stormwater conveyance system are required to alleviate the flooding.  These improvements vary depending on the cause and extent of flooding. No single solution will address the problems.  The Master Plan process provides a framework to consider multiple solutions under a single preferred alternative. Implementation will occur over the short-term and long-term time scales.

Existing ng Co Condi nditions ns  Minor System:  2-year design storm  92 % of storm sewers surcharge.  59 % of manholes surcharge.  5-year design storm  96 % of storm sewers surcharge.  68 % of manholes surcharge.  Major System:  29 trapped low points considered in the analysis.  9 of the 29 low points are contained within the road and boulevard.  9 of the 29 low points cause ponding onto private property.  11 of the 29 low points cause flooding of buildings or spill through private property  High Priority

Low P Points Lyon Avenue Flooding of houses. Odette Court Ponding contained in right-of-way.

Des esign gn A Alter ernatives es  Four alternatives developed for the Master Plan. Alternative 1 Alternative 2 Alternative 3 Alternative 4 Do Nothing Address Overland Flooding Meet Design Standards No Road Ponding Maintain the Private Measures: Private Measures: Private Measures: Status Quo. • Direct sump pumps to the • Direct sump pumps to the • Direct sump pumps to the road to reduce basement road to reduce basement road to reduce basement flooding. flooding. flooding. Targeted Strategies: Targeted Strategies: Regional Strategies: • Implement targeted • Implement targeted • Provide pump stations Increasing Cost and Complexity strategies at the 12 high strategies at the 12 high and ponds to facilitate 5- priority flooding locations priority flooding locations to year storm sewer capacity. to prevent overland prevent overland flooding of • Regrade roads or provide flooding of houses. houses. 100-year storm sewer capacity to remove ponding Regional Strategies: at trapped low points. • Provide pump stations and ponds to achieve design standards: - 5-year storm sewer capacity

Des esign gn A Alter ernatives es Alternative 1 Alternative 2 Alternative 3 Alternative 4 Do Nothing Address Overland Flooding Meet Design Standards No Road Ponding Maintain the Private Measures: Private Measures: Private Measures: Status Quo. • Direct sump pumps to the • Direct sump pumps to the • Direct sump pumps to the road to reduce basement road to reduce basement road to reduce basement flooding. flooding. flooding. Targeted Strategies: Targeted Strategies: Regional Strategies: • Implement targeted • Implement targeted • Provide pump stations strategies at the 12 high strategies at the 12 high and ponds to facilitate 5- priority flooding locations priority flooding locations to year storm sewer capacity. to prevent overland prevent overland flooding of • Regrade roads or provide flooding of houses. houses. 100-year storm sewer capacity to remove ponding Regional Strategies: at trapped low points. • Provide pump stations and ponds to achieve design standards: - 5-year storm sewer capacity. - 100-year maximum ponding depth of 0.3 m within the road right-of-way.

Alternative ve 1 1  Alternative 1: Do Nothing • Does not address flooding. • Does not meet design standards. • Pre-screened – not viable option .