Underground sand filters are a type of stormwater control measure designed to control stormwater runoff and save useable space simultaneously. Unlike other SCMs that are built above ground and take up large amounts of developable space, these devices are built underground. You find them often under parking lots or open green areas. They are typically accessed above ground through a manhole or Bilco door.

Underground Sand Filters are designed with separate chambers that control and treat stormwater runoff. Stormwater first enters a sediment chamber that is meant to allow solids and other particulates to settle before the water moves into the sand chamber. In the sand chamber, the water percolates down through layers of media intended to trap contaminates. An underdrain system at the bottom of the sand chamber allows processed stormwater to flow cleanly downstream.

Maintenance of these systems is typically completed monthly or quarterly depending on the system and the owner operations manual. Maintenance items include a general inspection of the device and chambers. Checking the orifices to ensure proper water flow in and out of the system. Removing trash and other debris from the system. Finally raking and fluffing of the sand chamber to ensure proper drainage.

At some point during the life of the device, the sediment chamber requires cleaning out. This varies based on the device, but it is determined by the storage capacity of the device. Once a system reaches a certain storage capacity in the sediment chamber the material must be removed. This service is usually completed with a Vacuum Truck for optimal efficiency.

Please contact us for questions regarding your underground sand filter or other SCMs. Triangle Pond Management proudly provides maintenance and repair of these devices as well as annual inspection services to ensure your devices are reported on time to the governing entity.

Before Photos

After Underground Sand Filter Maintenance