Assessing Vulnerability & Climate Change Impacts Youssef Habboush January-18-19

Outline Background Climate Change Recent Studies Risk Assessment Information Templates Moving Forward

Who We Are Population Area NS @ 950,000 (2017) NS @ 55,200 km2 HRM @ 403,000 (2016) HRM @ 5,500 km2 42% 10%

HRM @ 5,495 km2 PEI @5,660 km2 Source: HRM IMP Report 2017 PEI 72 Municipalities VS 1 Municipality HRM deals with infrastructure within Urban, Suburban, and Rural areas. Requiring extensive expertise.

Climate Change Assessment HRM receives 1200-1300 mm of rain annually; Extreme events likelihood on the rise; Extreme event >200mm in 24hr 16% annual precipitation increase by 2100; Projections indicate that the current 100yr event will be: 50yr event by 2020 25yr event by 2050 15yr event by 2080

Sea Level Rise & High Water Combination of Sea level rise Increasing storm surge Crustal subsidence (Sinking land) Extreme Total Sea Level (High Water in Meters) – Halifax Return Period 2000 2025 2055 2085 2100 10-Year 2.87 3.02 3.30 3.70 3.93 25-Year 2.97 3.12 3.40 3.80 4.03 50-Year 3.04 3.19 3.47 3.87 4.10 100-Year 3.11 3.26 3.54 3.94 4.17 Source: High Water Projected Values Based on Halifax, NS (Richards & Daigle, 2011)

Flooding Scenarios Flash Flood High intensity and short duration (summer thunderstorms) Heavy Rainfall >50mm in 24 hours (nor’easters/tropical storms) Multi-day Accumulation Rainfall during thaw cycle (run-off along frozen ground) Storm Surge (Costal high water) Storm events with high tides (HRM)

Water doesn’t differentiate between property lines nor Responsibility Water doesn’t differentiate between property lines nor Responsibility. It’s a shared problem between all affected parties.

Responsibilities Province of Nova Scotia Regulatory authority Owner of watercourses and some wetlands Halifax Water Owner of pipes and ditches Governed by Utility and Review Board Halifax Regional Municipality Manage overland flow from development and municipal lands Private Property Owner Maintain private infrastructure and site generated flow

Baseline Study In 2015, HRM and Halifax Water compiled a compendium of known areas prone to flooding within the service boundary. Initially, over 5700 drainage issue sites were identified. This list was refined down to 916 sites. The criteria used to refine the list included: Work was undertaken to address the issue. Duplicate sites were removed. Strictly private property issues were excluded.

Baseline Established The list of 916 sites was further jointly refined by HRM and Halifax Water staff to 30 key sites. Developing the 30 key sites did consider risk but did not attempt to quantify or measure it. National Disaster Mitigation Program: Flood Risk Assessment Study Consolidation and selection of certain sites in conjunction with historical and operational knowledge

Figure 1: Overview of HRM NDMP Site Locations 30 Sites Figure 1: Overview of HRM NDMP Site Locations

Study Objectives Develop a top 10 highest priority; Using the NDMP Risk Assessment Information Template (RAIT) developed by Public Safety Canada. Develop a preliminary mitigation strategy complete with order of magnitude costs estimates.

RAIT Criteria Infrastructure Public Safety Society Economic Environment Seasonal Conditions Return Period Likelihood

RAIT - Sample RAIT Criteria: The assessment considers the impacts of Climate Change in terms of the frequency, duration, and volume of extreme events, and its impact on municipal stormwater systems.

Methodology Desktop Research Site Visits Operation Staff Workshops Risk Assessment Information Template

Final Outcome Groupings Large Natural Watershed Systems Three Sites Localized Drainage Infrastructure Four Sites Tidal Influenced Systems

Sackville Rivers Key Site Characteristics Large Natural Watershed

Sackville Rivers Key Asset Inventory

Moving Forward Capital investment strategy for stormwater infrastructure Ownership and maintenance of stormwater systems Land development practices

Capital Investment Strategy NDMP: Funded by National Disaster Mitigation Program, HRM, and Halifax Water Next steps Identify cost sharing of mitigation measures then prioritize and program actions with Council

Ownership and Maintenance Work Management Guidelines developed Special Technical Committee with emphasis on operations Next Steps Continue implementation of Asset Management Programs

Land Development Practices Lot Grading By-law update NSUARB Stormwater Rate Hearing Concluded Direction from the Board regarding joint standards that consider quality New House Construction - Flood Resilient Design Guidelines Next Steps Stormwater Management By-law, Joint Standards W/ Halifax Water, and Green Infrastructure / Community Design standards

Questions Source: ESSC Integrated Stormwater Management Policy Presentation December 7,2017