Underground Detention Vaults

Underground Detention Vaults (Concrete)

Underground detention vaults are large buried concrete chambers designed to temporarily store stormwater runoff and release it at controlled rates to prevent downstream flooding and erosion. CMS provides underground vault inspections, structural evaluations, sediment assessments, and stormwater compliance support throughout North Carolina.

Underground Detention Pipe Systems (CMP/HDPE)

Underground detention pipe systems utilize large-diameter corrugated metal pipe (CMP) or high-density polyethylene (HDPE) to provide subsurface stormwater storage in commercial developments. CMS performs inspection, sediment level evaluation, and system performance assessments to ensure continued stormwater functionality and regulatory compliance.

Sand Filter Systems (Surface & Closed)

Sand filter systems use engineered sand media within concrete chambers to remove sediment, nutrients, and pollutants from stormwater runoff before discharge. CMS conducts system evaluations, media condition assessments, and structural inspections to maintain water quality performance under North Carolina stormwater standards.

Proprietary Filtration Devices (e.g., StormFilter)

Proprietary filtration devices are engineered stormwater treatment units designed to remove trash, oil, sediment, and fine pollutants in compact underground systems. CMS provides inspection, performance evaluation, and compliance documentation to ensure these systems continue meeting manufacturer specifications and NC DEQ requirements.

Infiltration Trenches / Infiltration Systems

Infiltration trench systems are stone-filled underground structures that promote groundwater recharge by allowing stormwater to infiltrate into native soils. CMS evaluates infiltration performance, sediment accumulation, and hydraulic function to protect long-term stormwater compliance in North Carolina.

Stormwater Chamber Systems (e.g., StormTech)

Stormwater chamber systems use modular plastic arch chambers installed underground to create high-capacity stormwater storage without sacrificing surface development space. CMS provides chamber system inspections, sediment assessments, and stormwater compliance evaluations to maintain design performance.

Catch Basins

Catch basins are underground stormwater structures designed to capture sediment and debris before runoff enters downstream pipe systems or treatment devices. CMS performs catch basin inspections, sediment evaluations, and structural assessments to prevent blockages and protect overall stormwater system integrity.

Underground Cisterns

Underground cisterns are large below-grade storage tanks designed to capture and store stormwater runoff for reuse, reducing peak discharge and supporting sustainable water management practices. CMS provides inspection, system evaluations, and compliance support to ensure proper storage capacity and operational reliability.

Stormwater Repairs – Underground SCM Devices

Underground SCM repairs address structural damage, clogged pipes, damaged vaults, or eroded chambers that compromise system performance. Timely repairs restore full hydraulic capacity and ensure water quality treatment goals are met. CMS offers targeted repair solutions to return underground systems to optimal operation while minimizing disruption to surrounding properties.

Compliance, Longevity & Sustainability:
Prompt repairs ensure systems remain compliant with regulatory requirements and avoid penalties. Restoring structural integrity protects the long-term durability of the underground infrastructure. Efficient repairs reduce material waste, extend asset life, and maintain sustainable stormwater management practices.

Importance of Stormwater Management 

Stormwater management is a critical part of protecting property, infrastructure, and natural resources by controlling runoff volume and reducing pollutants carried by rainwater. Engineered stormwater control measures (SCMs) such as wet ponds, bioretention basins, infiltration systems, and swales are designed to treat runoff, reduce erosion, and improve water quality before water enters streams, rivers, and lakes. Without effective stormwater management, uncontrolled runoff can cause flooding, property damage, and increased sedimentation in receiving waters, leading to non-point source pollution concerns. For commercial, industrial, and regulated sites across North Carolina, proactive stormwater management supports regulatory compliance and reduces long-term operational risks. CMS provides comprehensive stormwater solutions that help property owners plan, implement, and maintain stormwater systems to protect assets and meet performance expectations.

Maintenance of Stormwater SCMs

Routine maintenance of stormwater SCMs is essential for long-term performance, as sediment buildup, vegetation overgrowth, and clogged inlets can significantly diminish treatment capacity and hydraulic function. Regular maintenance ensures that SCMs, such as wet ponds, permeable pavements, and sand filters, continue to capture and treat stormwater runoff as designed. Without ongoing care, SCMs can fail to remove pollutants effectively, increasing the risk of flooding and environmental impacts downstream. CMS provides scheduled maintenance programs tailored to each SCM, helping clients avoid costly failures and ensuring reliable stormwater performance.

Repairs of Stormwater SCMs

Stormwater SCM repair services are critical when systems demonstrate structural issues, sediment reduction in storage capacity, or impaired hydraulic performance. Repairs may involve restructuring outlet controls, restoring eroded embankments, replacing damaged components, or rehabilitating clogged media in filtration systems. Timely SCM repairs prevent small issues from developing into system failures that compromise water quality and increase risk of flooding. CMS delivers stormwater system repair expertise that addresses both routine and non-routine corrections to restore SCMs to their original operating condition.

Inspections of Stormwater SCMs

Stormwater SCM inspections identify maintenance needs, structural concerns, and performance deficiencies that could reduce treatment effectiveness or lead to regulatory non-compliance. Quarterly, annual, and post-storm inspections help owners track sediment accumulation, vegetation conditions, and hydraulic function to ensure SCMs operate as intended. CMS utilizes certified stormwater inspectors and documented inspection protocols to provide thorough evaluations and detailed reporting. These professional inspections support stormwater compliance goals and help guide maintenance and repair planning for each SCM device.

Contact CMS Stormwater Today

NC Stormwater Links

NC Department of Environmental Quality

EPA Stormwater Program