Good Housekeeping BMPs, part 2: Stockpiling Management

Written by Wendi Lau

Despite all the confusing terms and acronyms, Erosion and Sediment Control is simply being responsible, taking precautions, and cleaning up after ourselves.

We continue looking at examples of Best Management Practices in the Good Housekeeping category.

Stockpiling Management

A stockpile is usually made up of excavated dirt or new gravel. Why pay attention to giant piles of dirt and gravel? Because loose dirt can easily blow off-site and wash into storm inlets. When it reaches the ocean, excess dirt and debris coats coral and can kill and its related ecosystem.

Did you know everything that flows down a gutter or storm drain goes directly to the ocean without stopping at a wastewater treatment facility first? That’s what “Flows to ocean” means. In Hawaii and many other states, wastewater from toilets and sink drains is separate from the stormwater system.

Stockpiling Management means:

  • Cover any stockpile not used in seven days or more.
  • Completely encircle the pile with a biosock or silt fence.
  • Sprinkle daily with water.
  • Maintain neat and safe piles of materials.

Deciding between a biosock or silt fence for containment depends on the site conditions. Usually, a biosock is enough.

Installation

Whether using a biosock or silt fence, it should completely surround the dirt or gravel pile, overlapping at the ends.

Here, a silt fence was used for stockpiling management instead of a biosock because a stream is only a few yards away.

Biosocks should be completely flush with the ground to avoid mud escaping.

Silt fences should be properly dug in 6” down and 6” across, like an L-shape, firmly tamped down, and fastened to rebar in three spots.

Please maintain silt fences and biosock socks, repaire holes, and right or repair fence steaks.

The City and County of Honolulu BMP Standard Details calls for rebar on silt fences, which do not break or dislodge when properly installed (18” down).

Deficiencies

Broken silt fence support

This silt fence will still function as intended in a light to medium rain. An extended, heavier storm could overflow this portion of the silt fence. Technically, it could be cited as “BMP not maintained” and the owner fined by a strict building or wastewater inspector. If rebar were used, as the BMP Standard Details Manual calls for, the supports would not break.

A biosock with gaps between it and the ground will allow sediment to escape when it rains.

Read “What Does an ESCP Coordinator Look for During an Inspection?” for more examples of stockpiling management and deficiencies.

For more information, I recommend the free webinar Urban Hydrology and Green Stormwater Infratructure from StormwaterOne and free ESCP Coordinator 2020 training from the City and County of Honolulu.

Next: Good Housekeeping part 3 – Spill Prevention & Control

All photos by Wendi Lau. Diagrams by City and County of Honolulu from The City and County of Honolulu BMP Standard Details, updated 2017.