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Exhibit C 7.1.H. - Page 34 <br /> utes for the water to stop flowing are clogged to some <br /> degree (Figure 4). , ; !, r t `-° - g <br /> During the site visit, the inspector can scout for - . <br /> weed growth and trash deposition. If the permeable " � �� .`� P. <br /> pavement is underdrained,the underdrain outlet should -1- 3,r44-K ` `- <br /> be checked to verify it is not blocked. If the visit occurs <br /> after a storm, a trickle of water would be expected from <br /> the underdrain. ;, . <br /> STREET SWEEPING <br /> bd <br /> RV <br /> Street sweeping is the most important maintenance task <br /> associated with permeable pavement. Street sweeping -1 <br /> can serve one of two purposes: preventive maintenance . <br /> and restorative maintenance. Preventive street sweeping <br /> is preferred. Preventive sweeping is regular, scheduled <br /> passes by a street sweeper during a calendar year. While <br /> the exact frequency has yet to be determined, it appears <br /> two to four visits per year for most permeable pavement <br /> applications is sufficient. If the permeable pavement has 4" <br /> been neglected for several years, however, preventive „. "`�"-- <br /> maintenance will not be sufficient, so restorative street <br /> sweeping will be required to restore a pavement's abil- :— <br /> ity to infiltrate water. The type of equipment needed to _ <br /> achieve either preventative maintenance or restorative <br /> maintenance is not the same. <br /> Types of Street Sweepers .� <br /> There are three main classes of street sweepers: (I) :-n - I <br /> mechanical, (2)regenerative air, and (3)vacuum. Exam- ' <br /> ples of mechanical and vacuum sweepers are shown in Figure 5.A small mechanical street sweeper(top)and the <br /> Figure 5. underpinnings of a vacuum sweeper(bottom). <br /> Mechanical street sweepers are the most com- <br /> mon street sweeper on the market. By some accounts, percent of street sweepers in the U.S. They function by <br /> approximately 70 percent of street sweepers in the U.S. applying a strong vacuum to a relatively narrow area <br /> are mechanical street sweepers (Mark Kinter1). Meehan- that lifts particles both at and below the surface of the <br /> ical sweepers employ a multiple brush approach to first pavement. Vacuum sweepers have demonstrated their <br /> move sediment and trash to the middle and then lift the ability to suction 3 to 4 inches of gravel from PICP and <br /> deposits onto a conveyor belt for temporary storage.The have the ability to restore infiltration to some types of <br /> brush bristles can penetrate some types of permeable pavements that have been grossly neglected. <br /> pavements, but not most. <br /> Regenerative air street sweepers are the second most Where do permeable pavements clog? <br /> common street sweeper, accounting for roughly 20 per- Permeable pavement systems clog at different locations <br /> cent of street sweepers in use in the U.S.They work by in their cross-section. Because of this, not one type of <br /> shooting air at an angle to the pavement, which effec- street sweeper is recommended for all types of perme- <br /> tively loosens dust and other fine particles at and near able pavements. Based upon anecdotal observation <br /> the surface of the pavement. Because air is blown across and research, here are the observed zones or depths of <br /> the carriage of the truck, a relatively minor vacuum is surface clogging. <br /> created,which then lifts the loosened particles into a Concrete grid pavers, because their gaps are filled <br /> hopper.This system removes surface-deposited sedi- with sand, act like a sand filter and trap most of the fine <br /> ments from all pavement types. <br /> Vacuum street sweepers are the least common and 'Mr.Kinter is an Elgin Street Sweeper marketing director.Conver- <br /> most expensive type of sweepr, and account for 10 sation took place in May 2009. <br /> 4 Urban Waterways <br />