All storm water management systems require maintenance. Pervious concrete systems are no exception to this rule, however the maintenance associated with pervious concrete systems is often misunderstood. Without proper education, this misunderstanding can lead to design professionals, or local government officials, unfairly favouring the use of conventional pavement systems.To put this into prospective, in a recently submitted development proposal, which included the design of our pervious concrete system, we had a local government official state that their only concern with approving a pervious concrete system was that they believed that there was a high risk of future issues if the development was not maintained properly. This was a perceived concern even though a pervious concrete system at a 20% infiltration capacity usually operates at a rate greater than the 100 year storm. While the statement has some merit, to fairly analyze this question both systems must be reviewed.
With a conventional impervious pavement storm water system, maintenance is usually required in the following ways:
- Routine power sweeping of the pavement surface. The frequency of this is dependant on the type of development, however once a year is quite common for most commercial developments.
- Periodic cleaning of catch basins, manholes, and debris / oil interceptors. If these devices are not properly maintained, the system will not function properly or fail causing water backup, ponding, etc. Additionally, where maintenance is absent pollution and debris is often washed into the local waterways.
- Detention tanks, overflow devices, and above ground ponds also require maintenance. Some of the new segmental plastic tanks have rough bottoms and are very difficult to clean without adding manholes, which would then require confined space procedures, or digging up of the system, to rectify.
- Overtime fees for maintenance are a reality during various times of the year, particularly when leaves clog drains, or if manholes are blocked by snow during a snow melt.
- During winter, excessive salting and sanding to deal with a slippery asphalt surfaces is common.
- Repairing asphalt degraded from petroleum products drippings from parked cars is also a major issue, but not directly related to storm water unless the interceptors are not cleaned as noted above.
- Have your landscape maintenance company use their blowers to removed any debris created during their work, or between periods of maintenance. This is very quick and usually of no additional charge.
- Vacuuming of the pavement surface. We recommend that this procedure be done twice a year, once in the spring, and again in the fall. Use a good walk behind vacuum, such as a Parker, which cleans into the pores of the pavement. It also picks up metal with a front end magnet and is powerful enough to pick up other general debris as large as pop cans.
- If there are any possible site design issues, make note of these during the routine vacuuming. If possible make changes to eliminate the issue causing the maintenance, or increase the preventative maintenance frequency for the problem area.
- For areas requiring reparative maintenance, use methods such as high volume low pressure water, or pressure washing.
We want a storm water system to control the water runoff quantity and rate, as well as keep pollution control in check at all times. A pervious concrete system does this better than any other system on the market today. It does require maintenance, and yes there is a cost to this, but the method and costs are not prohibitive in any way.
