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How to Stabilize a Sediment Filter

Storm sewers will typically convey considerable amounts of sediment to drainage ways until their drainage area is stabilized. If the sediment loading is particularly severe, the storm sewer will clog badly, or at best, be only partially functional. Sediment filters are put in place around the sewer inlet to contain sediment until the drainage area is stabilized. In general, these sediment filters must not interfere with ongoing construction activities and must allow for the accumulated sediment to be collected and disposed of. Straw bale sediment filters allow water to easily flow through their structure and are effective when the drainage area is not larger than 1 acre.

Things You'll Need

  • Straw bales
  • String
  • Wire (optional)
  • Shovel
  • Metal stakes
  • Hammer
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Instructions

    • 1

      Secure each straw bale with either string or wire. Place the binding around the sides of each bale and not under and over the bales. Secure the bakes tightly to prevent them from breaking under the pressure of the storm water.

    • 2

      Position the bales lengthwise surrounding the inlet. Place the bales in a single row and make sure that the ends of each bale are pressed firmly against the ends of the bale next to it.

    • 3

      Excavate a trench around the inlet. Construct this trench at least as wide as a single bale and make sure that it is at least 6 inches deep.

    • 4

      Wedge any loose straw between the bales to form as watertight a barrier as possible.

    • 5

      Use the soil that has been excavated to backfill. Pack this soil firmly against the bales and compact it slightly, using the back of a shovel. Although the barrier is designed as a sediment filter to prevent silt from passing through, it is important that the pure water component of the storm water can filter through the soil and straw.

    • 6

      Drive a minimum of two stakes through each bale with a hammer to anchor it securely in place. In situations where you expect the storm water will flow powerfully, a third stake per bale should be used. Position one stake on either side of the bale to make sure that it is firmly anchored. These stakes are as important as the wire or string binding, as they must keep the sediment filter barrier intact. The barrier will cease to work as a sediment filter, if one or more of the bales are washed or pushed away.