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Page 9 of 20 <br /> Storm Water Management System Assessment <br /> Orono Truck Station <br /> Outlet Control Structure <br /> East Pond <br /> Due to snow cover at the time of MFRA's first site visit, an inspection of the outlet control structures for both <br /> ponds could not be completed. The 2005 technical memorandum noted that a grate should be added to the <br /> 18 inch corrugated metal standpipe. At the time of the second inspection, it was observed that this <br /> maintenance issue hatl been resolved and that the standpipe and surrountling riprap were in good <br /> condition. The standpipe drains south to a ditch where runoff then flows overland to the west pond. The <br /> downstream carbon steel pipe is in good condition and no erosion was evident in the ditch. <br /> West Pond <br /> The outlet structure of the west pond appears to be a 30 inch flared end section. This flared entl section is <br /> adjacent to the 18 inch flared entl inlet and causes concern for short circuiting of the wet pond. At the time <br /> of the inspection, the outlet was clear of vegetation and in good condition. <br /> Survey <br /> East Pond <br /> A survey of the setliment depth was taken at two points in the east pond: between the inlet and outlet <br /> structures, antl in the eastern section of the pond. A viable thirtl point coultl not be surveyed due to the <br /> density of cattails. The coordinates of the two points have been provided so that their exact location may be <br /> revisited. Survey point locations are shown in Figure 6. <br /> ..t N r t <br /> � E � *. � '.�' •� 'r,,.,,�'�`",�„ti �/ � +� <br /> # �� .�"� � w ��~ '` �� i <br /> � � � t <br /> a.�""�' �,�, �I�"` _ _"_'"� <br /> �j' � �r,.,�w+.ir.eru'e�° � ! <br /> �� { 'ti <br /> �,...�1 � � C <br /> / ` � r �� � �' ( <br /> � � 'r-4i4' ` � �l � � � <br /> ► ��i� 1 +'- <br /> / � �q� 1 r �/ ��. �--� ' 938'. �� ` + r � • � <br /> at � �— � ��..� ' , �� <br /> A�� } �1 -� _V r '". ` � �'93�'- ♦ i <br /> / � � � - 1t� � �qr y <br /> f • ,: , > ? <br /> i n a ' .L + r -� �,t� `= <br /> / . �,� y" l �� ' / �9�� r. .� <br /> � e, ei`p ++� � .tt � e'�' ',,,r►�"" <br /> , ���y � <br /> � / .I�c '�y ` 'i r�6 �r� ,L '' � .^' <br /> � M' �� 6 �► � <br /> j � , ' . ,. ',.• '�IG.... <br /> ' ,,„„.�"" .� 3�irj� <br /> � <br /> I .•�,,,,,. ' � •. <br /> � <br /> ,�p — $ ' i „� s <br /> ... ..•' ... .... �+'!. <br /> � � . <br /> � �'' -' �. ! j ` <br /> / � p� <br /> Figure 6—Survey Point Locations East Pond <br />