D08.1 Stormwater Structure
D08.1.1 Stormwater Structure Cleaning
Stormwater structures capture runoff, connect pipes, provide access, control the water level in stormwater management systems, and/or allow excess runoff to discharge or overflow in a controlled manner.
Stormwater structures may include the following:
- Catch basin
- Inlet
- Sediment trap
- Maintenance hole
- Overflow structure with or without removable weir
- Observation well
- Clean-out
- Domed riser
Frequency: Semiannually (spring and fall)
D08.1.2 Stormwater Structure Maintenance Procedure
- Safety set-up: Set up safety perimeter.
- Inspect: Visually inspect stormwater structure and adjacent area for any immediate damage or potential problems, including any upstream pollution sources or locations of existing or potential vegetation debris. Inspect stormwater structure for signs of accumulated sediment, leaf litter,
and/or debris. Look for signs of settlement and/or washout around structures and attached pipes. Record all observations in the Maintenance Report Log and report as necessary. If possible, take photographs to document site conditions. - Prepare site for servicing: Remove any debris that has accumulated on top of the structure. Remove structure lid (inlet grate, manhole cover, or observation well cover) and set aside. Visually inspect interior of the structure for defects and evidence of illegal dumping. If illegal dumping has occurred, notify the proper authorities as necessary. Record observations/ damage in the Maintenance Report Log, include photos if possible, and report as necessary.
- Examine structure for any unintended or excessive standing water. Inspect for signs of mosquito larvae. If sediment trap is in place and contains standing water, inspect the drainage orifices for signs of clogging. These orifices are usually 1-inch diameter and located at the base of the structure. Remove any and all material clogging these orifices.
- Observe if the structure has a filter insert and follow separate guidelines in Inlet Filters for maintenance and replacement of filter insert.
- Cleaning: If using a vacuum truck, clean the interior of the structure and remove all debris or sediment contained in sump. Leave the weir in place. Properly train employees in use of the vacuum truck and follow all vacuum truck manufacturer recommended guidelines. If a removable weir is present and not sufficiently cleaned, use wrench/screwdriver or other tool to remove the bolts, lift it up and out of the structure, and set it to the side and repeat cleaning.
- Disposal: Ensure that the removed waste/sediment is properly disposed of and securely contained as to not run back into the stormwater system. Follow guidelines for disposal of waste/sediment on the local, state, and federal levels.
- Record: Make a note of any recorded observations in the Maintenance Report Log.
- Replace: Replace the stormwater structure cover and confirm it is tightly secured.
- Safety completion: Remove safety perimeter.
Inlet Filter Insert Cleaning
Manufactured filter inserts are designed to trap sediment, debris, trash, oil and grease. Filter inserts are located inside a catch basin or stormwater inlet. Clean filter inserts quarterly. Replace the filter insert pouch at least annually, or as necessary, during a cleaning task.
Frequency: Quarterly, unless established that a particular inlet requires less frequent cleaning.
Inlet Filter Insert Maintenance Procedure
- Safety set-up: Set up a safety perimeter.
- Inspect: Remove catch basin lid/grate with manhole pick and set safely aside. Visually inspect filter insert for evidence of defects and deterioration. Extensive damage to the filter (torn liner or mesh) requires immediate replacement. Record all observations in the Maintenance Report Log and report as necessary.
- Clean filter liner/mesh: Use an industrial vacuum or vacuum truck hose to remove any collected materials from the liner. Follow vacuum manufacturer’s directions for operation of the vacuum.
- Inspect filter hardware: After removal of collected materials from the filter, remove the filter insert as per manufacturer’s instructions. In many filters, this is done by unsnapping the tether from the D-ring. Set inlet filter insert to one side. Inspect the filter liner, gaskets, stainless steel frame, and mounting brackets, etc. for continued serviceability. Refer to the manufacturer’s manual to assist in locating these items. Correct minor damage and/or defects found during inspection. Record all damage and corrective actions undertaken in the Maintenance Report Log.
- Insert filter: After thoroughly inspecting the filter insert pouch for damage and continued serviceability, reattach the pouch tethers to the liner's D-ring (or equivalent part).
- Replace grate/lid: Replace the catch basin grate/lid and make sure it is secure.
- Safety completion: Remove safety perimeter.
Inlet Filter Insert Pouch Replacement
Manufactured filter inserts are designed to trap sediment, debris, trash, oil and grease. Filter inserts are in the interior of a catch basin or inlet. Replace the filter insert pouch least annually, or as necessary, in conjunction with cleaning task.
Frequency: Annual check, replace as needed.
Annually:
- Safety set-up: Set up a safety perimeter.
- Remove lid/grate: Remove catch basin lid/grate with maintenance hole pick and set safely aside.
- Remove and replace pouch: Remove and replace filter insert pouch. Properly dispose of removed pouches and debris according to local, state and federal regulations. Record observations in the Maintenance Report Log, include photos if possible, and report as necessary.
- Replace lid/grate: Replace the catch basin grate/lid and make sure it is secure.
- Safety completion: Remove safety perimeter