Viability of Stone Void Space in Underground Detention/Retention Systems

Many designers and regulators are faced with increasing storage demands for regional and site-specific detention requirements. This is especially true in the Gulf Coast and Atlantic regions where major storms over the past two decades have redefined traditional flood plain maps and design rainfall intensities. Coupled with rising land values, underground detention/retention systems (UDSs) offer a safe and effective means of reclaiming land usage. The efficiency—total storage relative to total excavation—of the UDS greatly impacts cost and the resulting benefit of electing to use underground storage versus an open pond. Therefore, many manufacturers and designers find every available means of supplying required storm water storage, including utilization of air within stone backfill. Available materials, construction methods, and proper designs dramatically impact the long-term reliability of stone void space and associated risk of flooding.