Sediment control
A sediment control is a practice or device designed to keep eroded
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...

Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...

 on a construction
In the fields of architecture and civil engineering, construction is a process that consists of the building or assembling of infrastructure. Far from being a single activity, large scale construction is a feat of human multitasking...

 site, so that it does not wash off and cause water pollution
Water pollution
Water pollution is the contamination of water bodies . Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds....

 to a nearby stream, river, lake, or bay. Sediment controls are usually employed together with erosion control
Erosion control
Erosion control is the practice of preventing or controlling wind or water erosion in agriculture, land development and construction. Effective erosion controls are important techniques in preventing water pollution and soil loss.-Introduction:...

s, which are designed to prevent or minimize erosion and thus reduce the need for sediment controls.

Commonly-used sediment controls

  • Check dam
    Check dam
    A check dam is a small dam, which can be either temporary or permanent, built across a minor channel, swale, bioswale, or drainage ditch. Similar to drop structures in purpose, they reduce erosion and gullying in the channel and allow sediments and pollutants to settle. They also lower the speed of...

  • Diversion dike
  • Fiber roll
    Fiber roll
    A fiber roll is a temporary erosion control and sediment control device used on construction sites to protect water quality in nearby streams, rivers, lakes and bays from sediment erosion...

  • Sand bag barrier
  • Sediment basin
    Sediment basin
    A sediment basin is a temporary pond built on a construction site to capture eroded or disturbed soil that is washed off during rain storms, and protect the water quality of a nearby stream, river, lake, or bay. The sediment-laden soil settles in the pond before the runoff is discharged...

  • Silt fence
    Silt fence
    A silt fence, sometimes called a "filter fence," is a temporary sediment control device used on construction sites to protect water quality in nearby streams, rivers, lakes and bays from sediment in stormwater runoff...

  • Storm drain inlet protection
  • Straw bale barrier
  • Turbidity curtain

Active treatment systems

Chemical treatment of sediment, commonly called an active treatment system, is a relatively new form of sediment control for the construction industry. It is designed to reduce turbidity
Turbidity is the cloudiness or haziness of a fluid caused by individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality....

 in nearby water bodies and involves collection of sediment-laden stormwater in a basin or tank, and adding a chemical flocculant. This causes the sediment to settle so it can be more easily removed from the water. Some of the flocculent chemicals used for sediment treatment are chitosan
Chitosan is a linear polysaccharide composed of randomly distributed β--linked D-glucosamine and N-acetyl-D-glucosamine...

 and polymer
A polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...

s such as polyacrylamide
Polyacrylamide is a polymer formed from acrylamide subunits. It can be synthesized as a simple linear-chain structure or cross-linked, typically using N,N-methylenebisacrylamide. Polyacrylamide is not toxic...

. The water is then pumped through a filtration
Filtration is commonly the mechanical or physical operation which is used for the separation of solids from fluids by interposing a medium through which only the fluid can pass...

 system, such as a sand
Sand filter
Sand filters are used for water purification. There are three main types;# rapid sand filters# upflow sand filters# slow sand filtersAll three methods are used extensively in the water industry throughout the world...

 or cartridge filter, prior to discharge. Chemical sediment control is currently used on some construction sites around the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, typically larger sites where there is a high potential for damage to nearby streams.

Another active treatment system design uses electrocoagulation to flocculate suspended particles in the stormwater, followed by a filtration stage.

Regulatory requirements

All states
U.S. state
A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 in the U.S. have laws requiring installation of erosion and sediment controls (ESCs) on construction sites of a specified size. Federal regulations require ESCs on sites 1 acre (0.404686 ha) and larger. Smaller sites which are part of a common plan of development (e.g. a residential subdivision
Subdivision (land)
Subdivision is the act of dividing land into pieces that are easier to sell or otherwise develop, usually via a plat. The former single piece as a whole is then known in the United States as a subdivision...

) are also required to have ESCs. In some states, non-contiguous sites under 1 acres (4,046.9 m²) are also required to have ESCs. For example, the State of Maryland
Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...

 requires ESCs on sites of 5000 sq ft (464.5 m²) or more. The sediment controls must be installed before the beginning of land disturbance (i.e. land clearing, grubbing and grading
Land grading
Grading in civil engineering and construction is the work of ensuring a level base, or one with a specified slope, for a construction work such as a foundation, the base course for a road or a railway, or landscape and garden improvements, or surface drainage...

) and must be maintained during the entire disturbance phase of construction.

See also

  • Certified Professional in Erosion and Sediment Control (CPESC)
    Certified Professional in Erosion and Sediment Control is a qualification indicating the holder has educational training, expertise and experience in controlling erosion and sedimentation, and met certification standards....

  • Geotechnical engineering
    Geotechnical engineering
    Geotechnical engineering is the branch of civil engineering concerned with the engineering behavior of earth materials. Geotechnical engineering is important in civil engineering, but is also used by military, mining, petroleum, or any other engineering concerned with construction on or in the ground...

  • Geotextile
    Geotextiles are permeable fabrics which, when used in association with soil, have the ability to separate, filter, reinforce, protect, or drain...

  • Nonpoint source pollution
    Nonpoint source pollution
    Nonpoint source pollution refers to both water and air pollution from diffuse sources. Nonpoint source water pollution affects a water body from sources such as polluted runoff from agricultural areas draining into a river, or wind-borne debris blowing out to sea. Nonpoint source air pollution...

  • Stormwater
    Stormwater is water that originates during precipitation events. It may also be used to apply to water that originates with snowmelt that enters the stormwater system...

  • Universal Soil Loss Equation
    Universal Soil Loss Equation
    The Universal Soil Loss Equation is a mathematical model used to describe soil erosion processes.Erosion models play critical roles in soil and water resource conservation and nonpoint source pollution assessments, including: sediment load assessment and inventory, conservation planning and design...

External links

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