806.3 Additional Temporary Erosion and Sediment Controls

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806.3.1 Temporary Measures

806.3.1.1 Mulching and Crimping

Application of mulch without seed may be used as a temporary best management practice if approved by the engineer. This practice is most applicable in late fall or early winter when grass seed would have little or no opportunity to germinate. Straw mulch is applied with a mulch blower or by hand and must be anchored (crimped) immediately after spreading to prevent wind blow. Application rates will vary based on the percent slope.

806.3.1.2 Brush Piles

Brush piles are considered to be a temporary BMP that is effective during clearing and grubbing operations. Tree tops, limbs, stumps and other vegetation, when placed in a drainage swale, can effectively impound gravel, soil and other eroded materials that otherwise may be carried off of MoDOT right of way during runoff periods. To be effective, brush piles are usually compressed by clearing equipment at the time of installation. Like other BMPs, brush piles are inspected following heavy rains to ensure that they are functioning as intended. If the brush pile is intended to serve as a semi-permanent structure for an extended period of time beyond the clearing and grubbing stage, clean out and maintenance equivalent to that required for ditch checks is required.

After land disturbance has been completed, removal should be discussed before heavy equipment leaves the site. In rural situations, and where maintenance issues are absent, the brush pile may be abandoned and left to decompose on its own.

806.3.2 Permanent Measures

Construction of permanent erosion and sediment control measures that may contribute to the control of siltation shall be accomplished at the earliest practicable time. This work shall consist of furnishing, installing, maintaining, and removing temporary control measures as shown on the plans or as ordered by the engineer. Berms, slope drains, ditch checks, sediment basins, seeding and mulching, silt fences, and other erosion and sediment control devices or methods shall be installed so as to ensure that erosion does not move soil particles off of MoDOT right of way. No work shall be started until the erosion and sediment control timetable and methods of operation have been approved.