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Exhibit C
<br /> Table 1.Street sweeper assignment to various permeable pavements
<br /> ' Pavement Type Schmutzdecke Depth Preventive Sweeper Restorative Sweeper
<br /> Concrete Grid Pavers filled with sand 0.5 inches Mechanical Mechanical
<br /> PICP filled with aggregate ' 15 to 2.0 inches ' Regenerative Air Vacuum
<br /> If Sand:< 1 inch If Sand: Vacuum?
<br /> Pervious concrete Regenerative Air
<br /> If Silt/Clay:>3 inches If Silt/Clay:Not known
<br /> If Sand:< i inch if Sand: Vacuum?
<br /> Pervious asphait Regenerative Air
<br /> If Silt/Clay:>3 inches If Silt/Clay:Not known
<br /> tively old permeable pavements located along the North
<br /> Carolina barrier islands and in the NC sandhills,both �Q � �° �
<br /> very sandy soil regions,demonstrated that despite being "
<br /> clogged, infiltration rates usually exceeded 1 in/hr. This �� �� '����
<br /> is because the pavement was clogged by sand. Designeis � �� � `�
<br /> and regulators should consider whether an infiltration rate �� `� �" _
<br /> of 1 to 2 inches per hour is acceptable. If so,the frequen- �� ��� `�'
<br /> cy of required street sweeping in some(albeit limited) � ���� �_�,�
<br /> parts of the U.S. is reduced.A recent analysis of rainfall � � �� ��
<br /> intensities in NC demonstrated that less than 2 percent of °'°�� �''
<br /> �,`
<br /> all rainfall intensities(as measured hourly)exceed 1 in/hr. , � �.-� �n ��� � ���
<br /> , ,� ,.� -,� � .�. � � �5� .���
<br /> PICP related specifics � ���� � '� �� ` ��� �� ��
<br /> y�� � � '- ��`,:�� � � �_
<br /> Street sweepers will remove fill aggregate that could � ��- - .- ���� ���� �=�� � �' .� . �_r� � .�,�
<br /> then pose a tripping hazard(Figure 8). So every time � � � � - � _���� �,�,- �
<br /> PICP is machine swept, aggregate refill is mandatory ���_ �������� ��"�� 3,�� �� ��`_���
<br /> .�. �
<br /> (Figure 8). Be mindful that not every aggregate may r.�����'�� .��,��� . ��'� w� �,rt, ��
<br /> be appropriate for the landowner and application. The �` � �.,,������� � , � � '��
<br /> ��R.F �, �
<br /> aggregate's color or hue and that of the PICP block � '` �'� °�����. �� � ��-, ��;�
<br /> could be im ortant to the landowner. Refillin a s is � � � ��� �"' ��� �" . `` �
<br /> P g g P � �° �� � �.�� �' �~ � �� ,�,��
<br /> a very easy process and is usually achieved by broom � a,P �� � �, � � �� � �� �� �,�
<br /> ,�; ��; � ��
<br /> sweeping. ��� ° � � -�, � � �
<br /> Vacuum sweepers are powerful and, if not carefully '� �. � � ��, W �'' � ` ;
<br /> � � � �
<br /> operated can sliction too much aQQre ate from the a s � =� � �� `�`��'°�`� ������ `� ��,� � ,��
<br /> � ao g g p �,,, � ��;� �` � � ��,,ti,, pr � �
<br /> and beneath the pavers. Care must be taken to verify that ,� �� - �°� �y ����� �,� ��
<br /> a°4'
<br /> the amount of suction provided by the vacuum sweeper is w ' ��' �' ��� ���� "� -
<br /> ,,�,"�� � �� ; � -. � � y�: ��a ��°.. �
<br /> not removing portions of the gravel base layer.This can `�*• �� � �-��-' � = � - �` .a �� �n. � �����v
<br /> be QutCkly CheCked by sttCking a penCil dOwn the vaCU- Figure 8.PICP gaps must be filled with aggregate to
<br /> umed gap to verify the depth of gravel suctioned is less prevent a tripping hazard(top).Gravel replacement is
<br /> than the depth of the block. simple and done with a push broom(bottom).
<br /> OTHER MAINTENANCE ISSUES: REMOVING structure, and its removal can be more destructive to the
<br /> UNWANTED VEGETATION structure of the pavement.
<br /> Vegetation is often a sign that too much sediment has One cautionary note: some permeable applications
<br /> accumulated, because the excess sediment provides an are meant to be grassed. Mowing may actually be the
<br /> environment for vegetation to survive. Weeds should be appropriate maintenance activity. If a parking lot is to
<br /> removed using a systemic herbicide such as glyphosate be mowed, please remember to catch the grass clippings
<br /> and then returning within the week to pull the weeds. before they are deposited on the pavement.Accumiila-
<br /> It is imperative to not let unwanted vegetation persist. tion of grass biomass (clippings) could fiirther limit
<br /> As weeds mature, it becomes harder to remove the root infiltration.
<br /> 6 Urban Waterways
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