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Exhibit C 7.1.H. - Page 32 <br /> passes through interconnected pores in both PC and PA. able pavement water pathways, rendering them much <br /> Permeable interlocking concrete pavements(PICP)are less permeable.This has been anecdotally observed at <br /> available in many different shapes and sizes. When laid, several permeable pavement applications across the <br /> the blocks form patterns that create openings through U.S. (Figures 2 and 3).After the tree detritus falls on to <br /> which rainfall can infiltrate. Concrete Grid Pavers the permeable pavement, it risks being ground into the <br /> (CGP)are an"older cousin"to PICP and have relatively pavement by passing vehicle tires. Large parking lots <br /> larger open areas that are filled with gravel,sand, or even that are fringed by trees have had their perimeters clog, <br /> a loamy sand top soil. Plastic reinforcement grid pay- but the middle portions did not clog(Figure 2). While <br /> ers(PG), also called geocells,consist of flexible plastic the purpose of this chapter/bulletin is not to dissuade <br /> interlocking units that allow for infiltration through large designers from incorporating vegetation in the parking <br /> gaps filled with gravel or topsoil planted with turfgrass. lot, designers do need to be mindful that any pavement <br /> A sand bedding layer and(more frequently)gravel base underneath a tree canopy is at a much higher risk of <br /> course are often added to increase infiltration and storage clogging than pavement free and clear of vegetation. <br /> for many of these paver systems. Sediment accumulation from disturbed areas sur- <br /> All permeable pavement types must be inspected and rounding the permeable pavement is the most frequent <br /> maintained.There are certain elements of maintenance cause of permeable pavement failure. Designers must <br /> that are common among permeable pavements and other take special care to inform contractors to minimize <br /> elements that are specific to one or two pavement types. exposure of permeable pavement to sediment during <br /> construction. Permeable pavements in residential areas <br /> DESIGNING AND CONSTRUCTING WITH are particularly at risk.As one home is completed, an <br /> MAINTENANCE IN MIND adjoining property may remain under construction. In <br /> Proper design can help avoid future maintenance prob- these cases,the likelihood of sediment deposition from <br /> lems.Typically, the most common permeable pavement wind, water, and tires is very high (Figure 3). <br /> performance concern is clogging. Pavements must allow LANDSCAPE MAINTENANCE ACTIVITIES: <br /> water to pass through their surface to be permeable. <br /> Designers can minimize the likelihood of clogging by AVOIDING PROBLEMS <br /> considering the two most likely clogging sources: veg- Property owners often incorporate landscape mainte- <br /> etative litter and sediment. nance as part their property upkeep. Common activities <br /> Parking lots with overhanging trees provide many include re-mulching and lawn mowing with discharge <br /> benefits: shading to cool pavement temperature and of clippings.An uninformed landscaper may deposit his <br /> improved aesthetics are obvious reasons to landscape mulch pile on the pavement immediately adjacent to the <br /> parking lots with trees and shrubs. Designers must be landscape bed he is beautifying or may discharge grass <br /> aware, however, of unintended consequences associated clippings onto the pavement. If that pavement is perme- <br /> with a leaf canopy overhanging a permeable applica- able, a clogging source has just been introduced.An <br /> tion.Vegetation debris and detritus collect in perme- easy way to avoid this issue is either to bag clippings or <br /> place the mulch pile on <br /> t' �, '* , , �_+ n } „ , a tarp that can be care- <br /> ,, fully removed to prevent <br /> ems° �4 ; YiS ' 8, <br /> �- � � s-,� ,� �� r � , ��n ; •....., � clippings or mulch from <br /> :.t 51. .r'�1� .- Q1.! -.;, f. _/` falling onto the perme- <br /> �` Fs� ,/l'"� n '^, ;�` ,�I. ;` ` ` able pavement. <br /> 'qy °"` In locations with <br /> f' , aY - snowfall, plowing is a <br /> ,?` . `z - :; - necessary maintenance <br /> `' activity that can have <br /> , , Nt, e an impact on perme- <br /> '- - _� - - .. — , "� . ,. able pavement function. <br /> " ." '` When non-spec (tEn- <br /> s Figure 2.Leaf and tree detritus collects in path- screened and unwashed) <br /> ways intended for water in P1CP located under- sand (meant for vehicle <br /> neath a tree line outside Chicago,IL. traction, not permeable <br /> pavement infiltration) is <br /> 2 Urban Waterways <br />