GeoStorage underground stormwater detention systems offer a reliable, cost effective alternative to tradtional detention systems. Geosynthetic reinforced stone walls support a reinforced concrete deck creating a large open chamber. The large chamber and porosity of the perimeter walls reduce the size of the required footprint and the components of the system are designed to ASSHTO HS-20 standards. Patents for this system have been issued or are pending in the following countries: United States, European Union, Canada, Mexico, Japan, Korea, China, India, Brazil, Australia, South Africa and Israel.