Underground Water Tanks - Modular Stormwater Tanks

Stormwater Storage Below Ground

Underground Stormwater Tanks

Modular underground systems for detention, infiltration and rainwater harvesting, designed to integrate stormwater storage within constrained urban and development sites

Atlantis underground stormwater systems provide modular below-ground storage solutions for detention, infiltration and rainwater harvesting applications. By locating stormwater storage beneath the surface, these systems help preserve valuable land for buildings, roads, landscaped areas, public spaces and other functional uses while integrating water management within the broader site design.

Their modular configuration allows storage capacity and system geometry to respond to project-specific requirements, including available footprint, required storage volume, site constraints and loading conditions. This flexibility enables underground storage to be incorporated across commercial developments, infrastructure projects, landscaped environments and complex urban sites where efficient use of space is an important consideration.

System selection and configuration should respond to the hydraulic objectives of the project, available footprint, cover and loading conditions, groundwater considerations, site characteristics and requirements for access and maintenance. These factors help determine the most appropriate approach for detention, infiltration or rainwater harvesting within the overall stormwater management strategy.

One System, Different Stormwater Strategies

Underground storage can be configured to respond to different stormwater management objectives, from controlling peak discharge to infiltration and water reuse

Infiltration

Provides temporary storage while allowing stormwater to infiltrate into suitable surrounding soils

Detention

Temporarily stores stormwater and releases it at a controlled rate

Note: Atlantis does not endorse detention systems. Detention systems discharge “recyclable” water into existing storm water systems where the water is contaminated causing heavy pollution downstream.

Rainwater Harvesting

Stores captured rainwater for suitable non-potable reuse applications

Approved for POTABLE WATER

(AS/NZ 4020)

Designed Around the Project

System Performance

Atlantis modular stormwater systems are characterised by measurable storage, hydraulic and structural properties. Performance varies by product geometry and configuration, allowing system selection to respond to project-specific storage requirements, flow conditions and applied loads.

Storage Efficiency

Atlantis modular tank systems are designed with high internal void ratios, allowing most of the system envelope to remain available for stormwater storage rather than being occupied by structural material. Across the current underground storage range, published void volumes are 90–95%, depending on the product configuration.

This relationship between gross system volume and internal void volume is a key factor when evaluating storage efficiency, particularly where available footprint or excavation depth is constrained.

Hydraulic Performance

The open structure provides continuous pathways through which water can move across the storage volume, with flow performance influenced by the geometry and configuration of the selected system.

Published flow-rate data characterizes this hydraulic performance under defined gradients, allowing different system configurations to be assessed against project-specific hydraulic requirements. These product-specific values provide technical input for system selection and configuration as part of the broader stormwater design.

Structural Performance

Vertical loads are transferred through the overlying cover and surface loading to the top of the system, while lateral earth pressures act against the side faces as a result of the surrounding ground. Together, these actions create a three-dimensional loading environment that must be considered when configuring the underground storage system.

System selection should consider these performance characteristics alongside cover depth, anticipated surface loads, surrounding ground conditions and other project-specific structural requirements.

OUR PRODUCTS

Engineered for a more resilient future

A range of modular stormwater systems designed to support detention, infiltration and rainwater harvesting across a wide variety of projects