Operation and maintenance of permeable pavement
Maintenance Agreements
Maintenance agreements should note which conventional parking lot maintenance tasks must be avoided (e.g., sanding, re-sealing, re-surfacing, power-washing). Signs should be posted on parking lots to indicate their stormwater function and special maintenance requirements.
When permeable pavements are installed on private residential or commercial property, owners must understand routine maintenance requirements. These requirements can be enforced via a deed restriction, drainage easement, maintenance agreement, or other mechanism enforceable by the local authority to help ensure that the permeable pavement is maintained and continues functioning. The mechanism should, if possible, grant authority for local agencies to enter the property for inspection or corrective action.
Maintenance Inspections
Maintenance of permeable pavement reviews its condition and performance. A spring maintenance inspection is recommended and cleanup conducted as needed. The following are recommended annual maintenance inspection points for permeable pavements:
- The drawdown rate should be measured at the observation well for three (3) days following a storm event in excess of 1/2 inch in depth. If standing water is still observed in the well after three days, this is a clear sign that subgrade soil clogging is a problem.
- Inspect the surface for evidence of sediment deposition, organic debris, staining or ponding that may indicate surface clogging. If any signs of clogging are noted, schedule a vacuum sweeper to remove deposited material. Then test sections using ASTM C1701 to ensure that the surface attains an infiltration rate of at least 10 in./hr.
- Inspect the structural integrity of the pavement surface, looking for signs of surface deterioration, such as slumping, cracking, spalling or broken pavers. Replace or repair affected areas as necessary.
- Check inlets, pretreatment cells and any flow diversion structures for sediment buildup and structural damage. Remove the sediment.
- Inspect the condition of the observation well and make sure it is capped.
- Inspect any contributing drainage area for any controllable sources of sediment or erosion.