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Erosion & Sediment Control

Examples of Common E&SC Controls and Considerations at UVa

Detailed descriptions of all E&SC controls can be found in the Virginia Erosion and Sediment Control Handbook.

 

Construction Entrances – MS-17, STD & SPEC 3.02

Purpose – reduce tracking of sediment from construction sites onto roadways

Important Considerations:

  • Filter fabric should be used under the gravel
  • Coarse aggregate should be used (2 or 3 inch)
  • At least 70 feet long by 12 feet wide – smaller entrances may be approved on sites where space constraints prohibit the installation of a properly sized entrance
  • Vehicles should be washed prior to exiting the site as necessary
  • A sediment trap should be included adjacent to the entrance to contain vehicle wash water


Example of a properly installed construction entrance.


Example of a properly installed construction entrance.


Mud being tracked off site because a construction entrance was not installed prior to earth moving activities.


All construction entrances require periodic maintenance and fresh stone to keep mud from being tracked off site.


All construction entrances require periodic maintenance and fresh stone to keep mud from being tracked off site.


Vehicle tires should be washed prior to leaving the site when conditions are muddy.

 

Inlet Protection – MS-4 and MS-10, STD & SPEC 3.07

Purpose – prevent sediment-laden water from entering storm drop inlets

Important Considerations:

  • Inlet protection must be installed before any land disturbing activities take place
  • The type of inlet protection used is dependent on the size of the area draining into the inlet
  • Inlet protection should be inspected regularly to determine if maintenance is required. Maintenance may include replacing silt fence, cleaning out gravel, or removing sediment that has built up around the inlet protection.


Block and gravel drop inlet installed in a sediment trap.


Silt fence inlet protection without framing, but a lot of vertical support.


Filter fabric installed under a drop inlet where vertical inlet protection would in the way.


Inlet protection should be inspected regularly.


Gutter buddies are commonly used to protect drop inlets along streets, where other forms of inlet protection would negatively impact traffic.


While easy to install, even gutter buddies require periodic maintenance to make sure they are properly aligned and to remove built up sediment.

 

Silt Fence – MS-4, STD & SPEC 3.05

Purpose – prevent movement of sediment off of construction site

Important Considerations:

  • Silt fence should be vertical and free from holes
  • When silt fence is half full or bulging due to sediment accumulation, it should be cleaned out
  • Silt fence should be located in such a way so as to discourage contractors from accidentally piling building materials on top of it
  • Silt fence should be keyed into the ground so that wash out underneath the fence does not occur


Multiple rows of silt fence can be used as necessary to slow flows and contain sediment.


Sediment build up behind silt fence should be cleaned out to prevent overtopping.


Damage by poorly placed materials.


Wash out under silt fence.

 

Stabilization of Soils – MS-1 and MS-2

Purpose – reduce the amount of exposed sediment on site

Important Considerations:

  • The sooner an area reaches final grade or the longer it is left undisturbed, the fewer E&SC issues there will be in that area
  • Soils must be stabilized within 7 days of reaching final grade
  • Soils must be stabilized within 7 days of reaching a grade where they will not be disturbed for 30 days
  • Permanent areas that will be left dormant for one year must be stabilized
  • Soil stockpiles must be protected with sediment trapping and or vegetation
  • Soil removed from the site and transferred from the site must also be stabilized according to these conditions


Progression of final stabilization of soil on a project site. (1/3)


Progression of final stabilization of soil on a project site. (2/3)


Progression of final stabilization of soil on a project site. (3/3)

 

Dewatering Excavations – MS-16 and MS-10, STD & SPEC 3.26

Purpose – reduce the amount of sediment entering the storm sewer system as a result of removing water from an excavation

Important Considerations:

  • Always pump into a sediment trap, use a filter bag, or other appropriate means to remove sediment from a dewatering operation
  • An excavation should never be pumped directly into a storm drain without use of a filter bag
  • Small excavations can be dewatered into a vegetated area large enough to allow the water to infiltrate and the sediment to drop out


A filter bag must be used before discharging water from an excavation into a storm drain.


Filter bag in place but not hooked up.


Filter bag properly installed and in use.

 

Concrete Washout – Stormwater Pollution Prevention Plan (SWPPP)

Purpose – contain wash water from concrete, mortar, and painting operations to prevent chemical-containing wash water from leaving the site

Important Considerations:

  • A concrete washout pit can easily be constructed by digging a pit below grade or constructing an actual basin using cement blocks or any other material
  • The washout pit will need to be cleaned out regularly to ensure there is room to add new material and it doesn't overflow
  • Hardened concrete from the pit can be thrown into a dumpster
  • Any water that contains anything other than potable water or rain water should not be discharged from the construction site
  • Keeping wash water contained helps keep the site clean and dry
  • More information can be found on the EPA's Concrete Washout website


Concrete washout running toward a stormwater conveyance.


Mud forming around a mortar mixer with no containment.


Containment of concrete washings.

 

Inspection and Maintenance – Stormwater Pollution Prevention Plan (SWPPP)

Purpose – on site inspections by contractors ensures problems are fixed in a timely manner

Important Considerations:

  • All E&SC measures require periodic maintenance
  • The site contractor is required to inspect and repair E&SC measures once every 7 days and within 24 hours of the end of a storm event of one half inch or greater
  • Written contractor inspection reports are to be kept on file with the SWPPP
  • Corrective actions are required within 24 hours of discovery


Mud is inevitable on most construction sites. Regular site inspections by on contractors and proactive maintenance of E&SC controls will help keep the mud on site where it belongs.

 

UVa E&SC Program personnel

  • Certified E&SC Program Administrator:
  • Certified E&SC Inspectors:

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Erosion & Sediment Control at the University of Virginia.

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