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In using temporary berms, it is important to recognize that the runoff collected must <br />• be periodically outleted to prevent severe erosion. Figure A-4 shows a temporary slope drain <br />installed for this purpose. An end section should be placed on the inlet of the pipe and a <br />crescent shaped earth berm constructed to channel runoff into the slope drain. Sumped stone <br />prorection may be necessary to prevent erosion az the drain outlet <br />Figure A-5 (page A-15) shows the installation of a flexible downdrain. The collapsible <br />pipe is about 20 inches in diameter and can be connected to an 18 inch pipe and section. It <br />is held in place by pinning or staking. Flaps with grommeu are provided every 20 feet for <br />this purpose. This type of temporary downdrairt system can be easily removed while addition <br />embattkntent is being placed and reinstalled at the end of each embankment operation. Also, <br />the location of the outlet can be easily changed when desired. Outlet protection is needed and <br />the pipe should be inspected for clogging after each storm. - <br />Another problem area where some fomt of temporary erosion control should be <br />provided is along the toe of embankment slopes. Where plans call for toe of slope ditches, <br />they should be constructed early in the grading operations. ~ However, ditches in themselves <br />may not offer the type of protection needed and additional controls should be installed. <br />Figures A-6a through A-6d (pages A-16 through A-19) show the plan details for brush <br />• barriers, silt and checl; dams. These devices are useful where brush is plentiful and can be <br />allowed to remain in place. <br />Figures A-7, A-8 and A-9 (pages A-20 through A-22) show the use of hay bales along <br />the toe of a slope. Hay bales can be effectively used in many locations as a temporary <br />measure to control erosion and prevent siltation. For long lengths of this type of barrier and <br />at low points where runoff will accumulate, overflow outlets should be provided as shown in <br />Figure A-7. Bales should be embedded inllte ground 4 to 6 inches to prevent water from <br />flowing under them. Figures A-8 and A-9 show the manner in which bales are to be placed <br />depending on whether the exiting ground slopes toward or away from the embattlmtent Bales <br />can remain in place until they rot, or be removed after they have served their purpose. <br />Replacement of damaged or silted bales may be necessary. <br />Figure A-10 (page A-23) is a composite picture indicating various temporary control <br />measures that can be employed during embankment construction. <br />• A-6 <br />