Types Of Permeable Hardscaping Systems Suitable For New Jersey

Permeable hardscaping is an essential tool for managing stormwater, reducing urban runoff, and improving groundwater recharge. In New Jersey, with its mix of urban areas, suburban developments, coastal plains, and steep slopes in the northwest, choosing the right permeable system requires matching material performance to local climate, soil, regulatory requirements, and intended use. This article outlines the main types of permeable hardscaping systems appropriate for New Jersey, explains how they perform in regional conditions, and offers concrete design and maintenance takeaways for homeowners, landscape architects, and contractors.

Why permeable hardscaping matters in New Jersey

New Jersey receives fairly high annual precipitation and has many developed areas with substantial impervious cover. Unmanaged stormwater contributes to flooding, stream erosion, combined sewer overflows, and pollution of waterways. Permeable hardscapes reduce runoff volume and peak flows, allow infiltration of stormwater to recharge aquifers, and can provide pollutant removal through filtration and biotic activity in supporting media.
New Jersey also presents challenges: variable soils (sandy coastal plains to clayey uplands), a range of groundwater table depths, and freeze-thaw cycles. Salt exposure near coasts and from winter road maintenance affects materials. These factors influence system selection, base design, and maintenance planning.

Overview of permeable hardscaping options

The major categories of permeable hardstone surfaces used in New Jersey are:

• Permeable interlocking concrete pavers (PICP)
• Pervious (permeable) concrete
• Porous asphalt
• Gravel and aggregate pavements with geogrid reinforcement
• Grass or turf reinforcement grids (GRM)
• Modular plastic or concrete grid systems (for heavy load or overflow areas)
• Infiltration beds and stone reservoirs used under other surfaces

Each system has strengths and constraints. The following sections describe each option, recommended contexts, design highlights, and maintenance requirements.

Permeable interlocking concrete pavers (PICP)

PICP consists of manufactured concrete pavers with joints left open and filled with clean, angular aggregate. Beneath the pavers is an open-graded stone reservoir that stores runoff and allows infiltration.

• Best uses: pedestrian areas, patios, driveways, parking bays, low to moderate vehicular traffic areas.
• Performance: Excellent surface infiltration, attractive finish options, and good load capacity when properly engineered. Pavers accommodate freeze-thaw well because each unit can move slightly without cracking.
• Subbase: Typically requires 8 to 18 inches of open-graded stone depending on traffic loads, infiltration rate, and desired storage.
• Edge restraint: Necessary to prevent lateral movement.
• Maintenance: Regular vacuum sweeping or brush-sweeping to remove fines and prevent clogging; annual inspection of joint material; occasional topping up of joint aggregate.

Pervious concrete

Pervious concrete is cast in place with a porous matrix that allows water to pass through the slab into an underlying stone reservoir.

• Best uses: Parking lots, low-speed roads, driveways, and pedestrian areas.
• Performance: High infiltration when free of clogging; good compressive strength for vehicle loads if mixture and base are designed correctly. More susceptible to clogging by fine sediments than PICP if not maintained.
• Subbase: Typically 6 to 12 inches of open-graded stone reservoir; thickness depends on design traffic and infiltration.
• Maintenance: Requires periodic vacuuming or pressure washing to remove sediments; avoid use of fine sand on the surface; quick cleaning after construction to remove cement paste from the surface.
• Winter: Pervious concrete can be salt sensitive; follow manufacturer recommendations for deicers and snowplow blade settings.

Porous asphalt

Porous asphalt uses an open-graded mix that allows water to drain through into an aggregate base.

• Best uses: Parking lots, low-speed roadways, driveways.
• Performance: Lower initial cost compared with pavers in some cases; good infiltration when maintained. Susceptible to rutting under heavy loads if binder content or base is inadequate.
• Subbase: Typically 8 to 18 inches of open-graded aggregate.
• Maintenance: Routine vacuum sweeping; avoid application of fine materials over the surface; periodic clog removal using specialized equipment.
• Consideration: Not all asphalt contractors have experience with porous mixes; proper mix and compaction are critical.

Gravel and aggregate pavements with geogrids

Open-graded gravel or crushed stone placed on a geotextile and reinforced with geogrids provides a permeable, stable surface for low-volume vehicular access.

• Best uses: Driveways, overflow parking, rural roads, service paths.
• Performance: Flexible, low-cost option that works well in sandy soils and in locations where visual appearance of stone is acceptable.
• Subbase: Depends on design traffic; geogrid allows reduced stone thickness in some cases.
• Maintenance: Periodic grading and addition of fresh stone; manage vegetation in edges; remove fines that migrate into the stone structure.

Grass or turf reinforcement grids (GRM)

Plastic or concrete grids filled with soil and turf, or with small stone, create a stabilized surface that supports vehicular loads while remaining permeable.

• Best uses: Occasional vehicle use areas, emergency access lanes, overflow parking, fire lanes.
• Performance: Provides green appearance, good infiltration, and load distribution when used with proper infill.
• Installation: Requires appropriate base course and infill depth; choose salt-tolerant grass species in coastal areas.
• Maintenance: Mowing, occasional re-seeding, and infill top-ups; avoid heavy repeated truck traffic unless designed for it.

Modular plastic or concrete grid systems

Rigid modular grids filled with stone or soil allow for heavy loads when designed with an adequate base and edge restraint.

• Best uses: Industrial yards, heavy vehicle parking, shoreline access paths, permeable paving where aesthetics are less critical.
• Performance: Durable and highly permeable; can be designed for high load-bearing requirements.

Subsurface infiltration beds and stone reservoirs

Many permeable surfaces rely on an underlying stone reservoir to store runoff temporarily. In some sites where surface permeability is limited, a separate infiltration bed or trench integrated with landscaping (bioretention) provides additional storage and treatment.

• Best uses: Adjunct to pervious surfaces, landscape areas, capturing roof runoff, or where additional storage is needed.
• Design: Use clean, angular stone, geotextile separation where appropriate, and underdrains only where infiltration to native soils is inadequate.

Site and soil considerations specific to New Jersey

• Soil infiltration testing: Conduct percolation or infiltration testing at design depths to determine native soil capacity. Sandy coastal plain soils infiltrate quickly; glacial till or clayey uplands may require underdrains or larger stone reservoirs.
• Groundwater and seasonal high water table: In areas with shallow groundwater, infiltration may be limited. Use underdrains and design overflow paths to avoid saturation of building foundations.
• Slopes: Permeable surfaces work best on gentle slopes. For steeper sites, break the slope into smaller infiltration cells with check dams, terraces, or vegetated swales.
• Freeze-thaw: Provide adequate drainage and use materials compatible with freeze-thaw action. Avoid trap of standing water in winter.

Design and construction best practices

• Design for overflow: Always provide a safe, defined overflow route for storms that exceed the system capacity.
• Proper base materials: Use open-graded stone free of fines as the reservoir layer. The base thickness should match expected loads and desired storm storage.
• Separation layers: Use geotextiles where imported stone might contaminate native soils, but avoid geotextiles that retain fines and reduce storage capacity in some designs.
• Edge restraints: Required for pavers and modular systems to maintain shape and load transfer.
• Professional design: For driveways, public parking, and larger installations consult a civil engineer or landscape architect experienced in stormwater BMPs and local permitting.

Maintenance guide and winter care

Regular maintenance is essential to preserve infiltration capacity and performance.

• Routine cleaning: Vacuum sweeping 1 to 4 times per year depending on tree cover and use. Frequency increases in leaf season.
• Sediment control: Prevent sediment transport onto permeable surfaces during construction and via nearby bare soils or runoff.
• Snow and ice control: Use plastic edged snowplow blades to avoid cutting the surface. Limit use of sand which can clog pores. Use chloride-based deicers sparingly; when possible, consult product and paving manufacturer recommendations for acceptable deicers.
• Repairs: Replace joint aggregate, re-level pavers, and replenish stone in gravel surfaces as needed.
• Inspect drains and underdrains: Where installed, check underdrain outlets for clogging and ensure they are flowing.

Choosing the right system: practical takeaways

• Match system to use: Choose PICP or pervious concrete for attractive, durable residential driveways and parking areas. Choose porous asphalt for larger lot applications where asphalt appearance is desired. Use gravel/geogrid or grass grids for low-volume, rural, or overflow areas.
• Test soils and groundwater: Before selecting a system, perform infiltration tests and identify seasonal high water table to determine need for underdrains and reservoir sizing.
• Design for maintenance: Pick a system compatible with your willingness to maintain. PICP is visually low-impact but needs vacuum sweeping; porous asphalt and pervious concrete also require regular cleaning.
• Consider winter conditions: In northern New Jersey and elevated sites, use materials and deicers that tolerate freeze-thaw. Near coasts, consider salt impacts on plantings and materials.
• Plan for longevity: Properly installed permeable systems that are maintained will last decades. Cutting initial corners on base preparation or using substandard aggregates will shorten service life.
• Coordinate with local regulations: Many New Jersey municipalities and the state have stormwater management requirements. Confirm local permitting and technical standards early in the design process.

Conclusion

Permeable hardscaping offers practical and effective options for stormwater management across New Jersey’s diverse landscapes. With thoughtful selection–based on soil permeability, expected loads, visual goals, and maintenance capacity–and with proper design of the reservoir and overflow provisions, these systems reduce runoff, protect waterways, and provide durable surfaces for everyday use. Engage experienced designers and contractors, conduct necessary soil testing, and commit to routine maintenance to ensure the chosen permeable system delivers long-term performance in New Jersey conditions.