Underground Detention Systems: Modular Stormwater Modules for Every Site
95% void ratio. Designed for AASHTO H-20 traffic applications. ASTM F2418 resin tested. No crane needed — two workers, one rubber mallet.
Why Engineers Specify Modular Underground Detention
The underground detention system that replaces gravel trenches and concrete vaults — at half the install time.
Designed for AASHTO H-20 / HS-25 Applications
Engineered for 40,000 lbs single-axle loads (H-20). XD variants are designed for HS-25 fire lane and highway applications. Manufacturer compression tested to 108 t/m² on a single module.
95% نسبة الفراغ (السعة القصوى للتخزين)
Each cubic foot you excavate stores 95% water. Gravel holds 30%. On a 10,000 cf project, that means excavating 350 cubic yards instead of 1,100. At $15-25/yd³ disposal, the math closes fast.
ASTM F2418 Tested — US Compliance Ready
Resin independently tested per ASTM F2418 for flexural modulus and tensile yield strength (TRI Environmental, Austin TX). Qualifies as a structural BMP under EPA NPDES guidelines. Meets Florida first-flush, California LID, and Texas flood detention requirements.
100% بولي بروبيلين معاد تدويره
100% industrial-grade recycled polypropylene with proprietary performance additives. Resists road salts, diesel fuel, motor oils, and soil acids. Operating range: -22 °F to 248 °F. Contributes to LEED Sustainable Sites credits.
تركيب سريع “Snap-Lock”
18.7 lbs per module. Two workers assemble 4,000 cubic feet per day with a 2×4 and a dead-blow hammer. No crane rental, no formwork, no 28-day cure. A typical system installs in 8 hours with a 3-person crew.
قابل للفحص والصيانة
Compatible with standard isolator row configurations. Wrap one row separately in geotextile to trap sediment upstream. Inspection ports and cleanout risers allow periodic Jet-Vac maintenance without excavating the system.
One Subsurface Detention System, Two Configurations
Same stormwater modules. Different liner. Your municipal stormwater ordinance determines which configuration you need.
Detention — Flood Control & Peak Flow Reduction
The underground detention pond configuration. Captures stormwater runoff and releases it slowly to a downstream storm sewer at municipal permit rates.
- Seal the module array with HDPE or LLDPE impermeable غشاء جيولوجي, protected by non-woven fleece on both faces
- Install a flow-control manhole with orifice plate or weir to restrict discharge to pre-development rates
- Required for Texas/Houston flood control zones, sites with non-draining clay soils, and any municipality that caps post-development peak discharge
- Qualifies as a structural BMP under EPA NPDES stormwater guidelines
Upstream pretreatment required: silt traps, hydrodynamic separators, or inlet leaf baskets to prevent sediment from entering the module array.
Infiltration — Groundwater Recharge & LID Compliance
The subsurface detention basin that lets water soak into the ground instead of leaving the site. Same modules, no membrane.
- Wrap the module array in AASHTO Class 2 non-woven permeable القماش الجيولوجي — water passes through into the subsoil
- Place on a 6 in. leveled layer of clean angular crushed stone for drainage and load distribution
- Designed for California LID compliance, dry wells, septic drain field replacement, and groundwater recharge mandates
- No flow-control manhole needed — water exfiltrates freely into permeable subsoil at the site’s natural infiltration rate
Some jurisdictions require a hybrid: infiltration on the base, impermeable liner on the sides. Confirm with your local stormwater authority.
Technical Specifications — Designed for AASHTO H-20 / HS-25 Applications
Two module sizes. Four duty variants. Manufacturer compression tested to 30 tonnes (108 t/m²) on a single module.
وحدة مياه الأمطار 6841 (ارتفاع 17.7 بوصة)
| مكدس | الحجم (مم) | حجم الخزان (قدم مكعب) | حجم الخزان (غالون) | صافي المياه (قدم مكعب) | صافي المياه (غالون) |
| أعزب | 26.8 × 16.1 × 17.7 بوصة (680 × 410 × 450 مم) | 4.44 | 33.22 | 4.31 | 32.21 |
| مزدوج | 53.5 × 16.1 × 17.7 بوصة (1360 × 410 × 450 ملم) | 8.89 | 66.44 | 8.63 | 63.05 |
| ثلاثي | 80.3 × 16.1 × 17.7 بوصة (2040 × 410 × 450 ملم) | 12.93 | 97.62 | 12.54 | 93.81 |
| رباعي | 107.1 × 16.1 × 17.7 بوصة (2720 × 410 × 450 ملم) | 17.17 | 128.47 | 16.65 | 124.58 |
| بنت | 133.9 × 16.1 × 17.7 بوصة (3400 × 410 × 450 ملم) | 21.42 | 160.21 | 20.78 | 155.41 |
وحدة مياه الأمطار 8053 (ارتفاع 20.9 بوصة)
| مكدس | الحجم (مم) | حجم الخزان (قدم مكعب) | حجم الخزان (غالون) | صافي المياه (قدم مكعب) | صافي المياه (غالون) |
| أعزب | 31.5 × 19.3 × 20.9 بوصة (800 × 490 × 530 ملم) | 6.02 | 45.12 | 5.84 | 43.76 |
| مزدوج | 63.0 × 19.3 × 20.9 بوصة (1600 × 490 × 530 ملم) | 12.04 | 90.24 | 11.68 | 87.52 |
| ثلاثي | 94.5 × 19.3 × 20.9 بوصة (2400 × 490 × 530 ملم) | 18.06 | 135.36 | 17.52 | 131.28 |
| رباعي | 126.0 × 19.3 × 20.9 بوصة (3200 × 490 × 530 ملم) | 24.08 | 180.48 | 23.36 | 175.04 |
| بنت | 157.5 × 19.3 × 20.9 بوصة (4000 × 490 × 530 ملم) | 30.10 | 225.60 | 29.20 | 218.80 |
Duty Variants & Load Ratings
| Variant | ARW-6841 Rating | ARW-8053 Rating | التطبيق النموذجي |
| LD | 44,000 lbs (20 t) | 44,000 lbs (20 t) | Landscaped areas, pedestrian plazas |
| SD | 88,000 lbs (40 t) | 88,000 lbs (40 t) | Residential driveways, light vehicle traffic |
| HD | 8,200 lbs/ft² (40 t/m²) | 12,300 lbs/ft² (60 t/m²) | Commercial parking lots, access roads |
| XD | 12,300 lbs/ft² (60 t/m²) | 16,400 lbs/ft² (80 t/m²) | Fire lanes, highways, industrial yards |
تصنيفات المواد والهيكل
- المواد: 100% industrial-grade recycled polypropylene with proprietary performance additives. Virgin PP available for specific project requirements.
- تصنيف الحمولة: Designed for AASHTO H-20 / HS-25 applications. Engineered for 40,000 lbs single-axle loads under commercial parking lots and roadways.
- المقاومة الكيميائية: Unaffected by road salts, diesel fuel, motor oils, and naturally occurring soil acids and alkalis.
- نطاق درجة الحرارة: -22 °F to 248 °F (-30 °C to 120 °C).
- المتانة: Polypropylene does not rust, rot, or degrade in buried conditions. Designed for long-term underground service.
الأداء الهيدروليكي
- نسبة الفراغ: 95% net void space. Each cubic foot you excavate stores 95% water versus 30% for gravel.
- التطبيقات: Underground stormwater detention (flood control), infiltration basins (groundwater recharge), and rainwater harvesting.
- الوصلات: Universal compatibility with 4 in. to 12 in. Schedule 40 PVC and standard corrugated HDPE pipe.
- Flow Control: Orifice plate or weir-type manholes restrict discharge to municipal permit rates for 2-year through 100-year design storms.
- التكديس: Up to 6 layers (Pent configuration) for maximum storage depth in constrained footprints.
الدعم الهندسي والموارد
- Material Color: Standard Industrial Black (UV Stabilized Recycled PP).
- CAD & Submittals: تفاصيل CAD كاملة، وأدلة التثبيت خطوة بخطوة، وحزم التقديم متاحة عند الطلب.
- Stamped Layouts: We provide project-specific stamped engineering layouts with cover depth designs and pipe penetration details.
- Compliance: ASTM F2418 resin tested by TRI Environmental. Qualifies as structural BMP under EPA NPDES stormwater guidelines.
- Turnaround: Typical proposal and layout delivery within 2 business days.
Underground Detention vs. Concrete Vaults vs. Surface Ponds
Installed cost per cubic foot and available land drive most detention decisions. Here is where four standard approaches compare.
| نوع النظام | Material ($/cf) | Installed ($/cf) | Install Speed | Land Footprint |
| Modular Geocellular | $4.50 – $6.50 | $8.50 – $13.00 | 4,000 cf/day, 2 workers | Minimal (below grade) |
| Arch Chambers (HDPE) | $6.00 – $8.00 | $12.50 – $17.00 | Moderate, crane required | Minimal (below grade) |
| Gravel / Stone Beds | $3.50 – $5.00 | $9.00 – $13.50 | Slow, compaction required | Large (30% void only) |
| Surface Detention Basin | غير متاح | $0.30 – $1.00 | Fast, earthwork only | Very large |
Gravel beds store water too, but at 30% void ratio versus 95% for modular crates, you need 3x the excavation volume. On a 10,000 cf project, that is the difference between removing 350 cubic yards of soil and 1,100 cubic yards. At $15–$25 per cubic yard for excavation and disposal, the smaller dig often offsets the higher material cost entirely.
One honest note: if your site has available acreage and no traffic loading requirement, a surface detention basin is the most cost-effective choice by a wide margin. Modular underground detention earns its place on constrained sites where land value or traffic loading justifies the premium.
Need a Stamped Layout and Cover Design for Your Underground Detention System?
Installation: Six Steps, Two Workers, No Crane
Snap-lock assembly with hand tools. A 4,000 cubic-foot underground detention system typically installs in 8 hours with a 3-person crew.
Project Case Studies
Verified installations using modular geocellular underground detention systems in California.
Commercial Research Campus — San Diego, CA
Challenge. A 12-acre biotech campus needed two separate underground detention systems: one for first-flush water quality capture, the second for 100-year peak flow detention. No surface area available for ponds.
Solution. Two modular underground detention systems beneath the parking structure. Tank 1: 9,737 cubic feet (first flush). Tank 2: 17,939 cubic feet (peak flow). HS-20 rated modules stacked 3 layers deep.
Result. Both systems fit within the existing building footprint. Zero surface land consumed. Field assembly completed in under 2 weeks with a crew of 4.
Golf Course Flood Detention — Palm Desert, CA
Challenge. A Coachella Valley golf course required 99,000 cubic feet of stormwater flood control detention for monsoon storm events. The system had to fit beneath irrigated turf without disrupting play.
Solution. Modular geocellular crates installed in phases across multiple fairway corridors. Geomembrane-lined for full detention. Discharge controlled through orifice manholes.
Result. 99,000 cubic feet of underground stormwater detention capacity for the 100-year design storm, with zero visible surface impact. Turf restoration completed within one growing season.
Frequently Asked Questions — Underground Detention Systems
Project Gallery: Underground Detention and Infiltration Installations
See our modular systems in action—from heavy-duty parking lot detention basins to high-capacity residential dry wells.
Distribute Underground Detention Systems. Full Technical Support Included.
Become an authorized distributor of our modular stormwater detention and infiltration systems. We provide stamped engineering layouts, installation training, marketing materials, and qualified project leads. Factory-direct pricing with no minimum order.
English
Arabic
French
Russian
Spanish