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Building in Squamish: Navigating Flood Zones and Zoning Regulations

Dec 25, 2024By NewlinesADU
NewlinesADU

Building in Squamish: Navigating Flood Zones and Zoning Regulations

Flood-Resistant Construction Tips


Squamish's breathtaking natural surroundings come with unique construction challenges, particularly when it comes to flood zones. With rivers, alluvial fans, and coastal areas prone to flooding, developers must carefully navigate floodplain bylaws and zoning regulations to ensure safe, compliant, and resilient builds.

In this post, we’ll break down key flood zone regulations, zoning considerations, and provide practical tips for building in Squamish's flood-prone areas, especially for those planning to construct an accessory dwelling unit, carriage home, or coach house.

 
Understanding Flood Zones in Squamish
The District of Squamish (DOS) has implemented a comprehensive Integrated Flood Hazard Management Plan (IFHMP) to mitigate flood risks. This plan identifies flood hazard areas along major rivers like the Squamish, Cheakamus, and Mamquam, as well as in low-lying coastal regions.

Key policies are guided by three documents:

  • Official Community Plan (OCP)
  • Development Permit Area 2 (DPA2) - Protection from Flood Hazards
  • Floodplain Bylaw

These frameworks dictate where and how development can occur, ensuring that communities are protected from the impacts of flooding.

Squamish Flood Hazard
Squamish Flood Hazard DPA2 map

 
What is Development Permit Area 2 (DPA2)?
DPA2 governs development within Primary and Secondary Floodways as well as Debris Flow Hazard Areas. The goal is to maintain flood conveyance capacity and prevent structures from impeding floodwaters.

Primary Floodways: Development is highly restricted. Only certain areas, like the Cheakamus River zone, allow conditional development.

Secondary Floodways: Development is permitted but requires certification by a Qualified Professional (QP). Projects must meet strict setback regulations.

Debris Flow Areas: These zones are vulnerable to landslides and debris flows, requiring extra precautions and hazard assessments.
 
Floodplain Bylaw and Flood Construction Levels (FCL)
The Floodplain Bylaw sets mandatory Flood Construction Levels (FCL), requiring habitable areas to be elevated above potential flood levels.

FCL Requirements:

  • Habitable floors must be built above the established FCL.
  • Mechanical and electrical equipment must also be elevated.
  • Flood-resistant materials must be used below the FCL to minimize damage.
  • Exemptions: Certain non-residential buildings in downtown Squamish may qualify for FCL exemptions under specific conditions.
     
    Zoning and Controlled Densification
    Squamish has designated Controlled Densification Areas that manage growth in flood-prone zones:

Restricted Densification Areas: Development is limited to preserve safety.
Conditional Densification Areas: Development may proceed if strict conditions, including flood mitigation, are met.
Limited Densification Areas: Moderate development is allowed, often capped at duplex zoning levels.

These zoning controls ensure that Squamish's growth aligns with flood mitigation efforts, balancing development with public safety.


Tips for Building in Flood Zones

  • Engage a Qualified Professional Early
  • Floodplain development requires technical assessments and certifications.
  • Engage geotechnical and engineers early to streamline approvals.
  • Choose Flood-Resistant Materials


For areas below the FCL, use:

  • Concrete for foundations
  • Galvanized or stainless steel framing to prevent rust and corrosion
  • Closed-cell spray foam, rigid foam insulation or ICF foundation
  • Raise HVAC units, electrical panels, and plumbing fixtures above the FCL.
  • Incorporate Flood Vents and Breakaway Walls. These features allow water to flow through non-habitable areas, reducing structural damage during floods.
  • Review Squamish WebMap and Zoning Bylaws
  • Plan for Drainage and Erosion Control
  • Incorporate swales, permeable surfaces, and reinforced drainage to prevent water from pooling around foundations.
ICF foundation
ICF foundation


 
Building for Resilience
Squamish's unique landscape calls for thoughtful, resilient construction practices. By adhering to zoning regulations, embracing flood-resistant materials, and designing for flood resilience, you can build safe, durable structures that withstand the region's environmental challenges.

For Builders and homeowners alike, understanding the intricacies of flood zone construction is key to ensuring long-term success and safety in Squamish.

NewlinesADU is here to guide you through every step of the process, from permits to final construction. Let us take care of the complexities so you can focus on creating the perfect Accessory Dwelling Unit to your home.