How Cities Are Saving $4–6 Million Per Kilometre Using Permeable Road Shoulders Instead of Storm Sewer Replacement

Municipal stormwater infrastructure across Canada and the United States is reaching a breaking point.

Storm sewer systems were designed decades ago, long before:

• Increased rainfall intensity

• Urban densification

• Higher impermeable surface coverage

  
  

Today, many cities are facing a costly reality:

Storm sewer replacement costs $4.5-7 million USD per mile ($4-6 million CAD per kilometre) often with multi-year disruption and limited long-term resilience.

For municipal engineers and public works departments, the question is no longer if infrastructure needs to be upgraded — but how to do it without overwhelming capital budgets...

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Taylor Davis, presenting at the American Society of Civil Engineering conference in Jacksonville Florida, March 2, 2026 on Low Impact Development and permeable paving technologies.

A New Approach: Permeable Road Shoulders as Decentralized Stormwater Infrastructure

Instead of expanding underground storm sewer capacity, cities are beginning to adopt permeable pavement systems as a form of decentralized stormwater management infrastructure.

PurePave Technologies has developed a system where a 4-foot-wide permeable road shoulder is installed alongside existing roads.

This shoulder:

• Intercepts rainfall at the surface

• Allows immediate infiltration into the base layer

• Reduces runoff entering catch basins

• Lowers peak flow rates in storm sewer systems

The Result:

Reduced hydraulic load on existing infrastructure — often bringing systems back within design capacity without replacement.

Demonstrating PurePave's data-validated sensor technology and distributed stormwater systems to American Civil Engineers: Save 4-6 Million per mile by using PurePave's sensor-monitored Permeable Roadway systems.

Why Permeable Shoulders Work (Stormwater Engineering Perspective)

Storm sewer failure is not typically caused by total rainfall volume — but by peak flow intensity.

By capturing water at the edge of the roadway:

• Runoff is distributed over time

• Flow spikes are reduced

• Pipe capacity is no longer exceeded

This aligns with Low Impact Development (LID) and green infrastructure strategies increasingly adopted across North America.

Key Search Terms Embedded:

• Stormwater management solutions for municipalities

• Permeable pavement road design

• Reduce stormwater runoff from roads

• Alternative to storm sewer replacement

Measured Performance of PurePave Permeable Systems

PurePave is engineered for high-performance stormwater infiltration in cold climates, with data-backed performance metrics:

• Infiltration capacity: up to 38,000 L/m²/hour

• Total Suspended Solids (TSS) removal: up to 98%

• Runoff coefficient: ~0.15

• Flexural strength: ~6.18 MPa

• Strain capacity: ~1.2% (flexible, crack-resistant)

What This Means for Municipal Systems:

• Significant reduction in runoff entering pipes

• Improved water quality before groundwater recharge

• Reduced long-term maintenance vs traditional systems

Designed for Canadian Freeze-Thaw Conditions

A major limitation of traditional permeable systems (like porous asphalt and pervious concrete) is performance degradation in freeze-thaw environments.

PurePave is specifically engineered to:

• Maintain permeability during winter conditions

• Reduce surface ice formation

• Prevent cracking from freeze expansion

• Extend lifecycle beyond conventional permeable materials

Why Not Porous Asphalt or Pervious Concrete?

Municipal engineers often evaluate multiple permeable options.

Common limitations of traditional systems:

Porous Asphalt:

• Lower structural strength

• Susceptible to clogging

• Degrades under freeze-thaw cycles

Pervious Concrete:

• Brittle, prone to cracking

• Requires strict installation conditions

• Higher failure rates in cold climates

PurePave Advantage:

• Flexible, resin-bound system

• Higher durability under load and temperature variation

• Lower maintenance with sustained infiltration performance

Cost Comparison: Sewer Replacement vs Permeable Infrastructure

Option A: Storm Sewer Replacement

• $4–6 million per kilometre

• Full excavation and road disruption

• 2–3 year project timelines

• High social and economic impact

Option B: PurePave Permeable Road Shoulders

• Fraction of the cost

• Installed in days, not years

• Minimal disruption to traffic and communities

• Scalable across priority areas

Strategic Outcome:

Extend or eliminate the need for sewer replacement by reducing system load instead of increasing capacity.

From Material to Infrastructure Layer

PurePave is not just a paving material.

It is a decentralized stormwater infrastructure system that measures, manages, and reduces runoff at the source.

When deployed at scale, permeable shoulders act as:

• Distributed infiltration systems

• Load-balancing infrastructure for storm networks

• Climate-resilient upgrades without excavation

  
  

Applications for Municipal Deployment

• Road shoulders and rural roads

• Urban corridors with drainage constraints

• Highway edges and medians

• Parking lanes and overflow areas

For Municipal Engineers and Decision Makers

PurePave works with:

• Municipal engineering teams

• Public works departments

• Urban planners and consultants

To provide:

• Stormwater load modeling

• Infiltration performance analysis

• Cost comparison vs sewer expansion

• Specification-ready system designs

Projects and specifications have been developed with:

• City of Ottawa

• City of Toronto

• New York City

Request a Stormwater Infrastructure Assessment

Municipalities evaluating alternatives to storm sewer replacement can request:

• A stormwater load reduction analysis

• A cost comparison vs traditional infrastructure upgrades

• A pilot project feasibility assessment

Contact PurePave Technologies📧 projects@purepave.com📞 +1-888-212-PURE