Silt Trap 272m45

Silt trap A silt trap is a designated area where water that is contaminated with suspended sediment as a result of construction activity or water runoff is contained. While the water is in the trap, the sediment can settle to the bottom of the trap until it can be removed. These devices can be made using silt curtains, silt fences or a series of shallow ponds to naturally filter the sediment from the water before it reaches a stream or clean body of water. Environmental protection efforts, such as the silt trap, are often seen in conjunction with mining or construction. Activity from these industries can result in the production of grain-size particles, stone dust and other components that create suspended sediment when caught up in water runoff during rainfall. As the rainwater carries these particles and other pollutants to streams, rivers and lakes, the suspended sediment can cause a serious issue for the fish and other wildlife that inhabit these waters. In some cases, the silt trap might also serve an additional purpose. Particularly in the mining industry, it becomes the last opportunity to reclaim precious metal ores that otherwise might have been lost. Settling tables, sluices and gold pans are time-tested methods of reclaiming gold, and these methods all work on the same principles as a silt trap. Many mining companies that produce ore in areas where precious metals are found might also regularly remove the accumulated sediment in their traps and process it to reclaim the precious metals that can be found. 4) @jcraig - The sedimentation ponds you described are very good at sediment control. They are great places for wildlife, too. The problem is that they can be expensive. They can only be put in certain areas and cost some money to set up. Given a choice, the ordinary farmer doesn't care where the water goes if it costs him money. To this point, most of the sedimentation ponds have been installed as pilot projects by universities. I believe that strip mines do have regulations saying that they must have ponds, though. The nutrient runoff from farms is bad, but runoff from mines can be toxic to everything around it. Most of the pollution is a combination of the chemicals used to mine the ore as well as things used to separate the ore from rock. Sulfuric acid is often used to mine copper, and this has turned into a huge problem in Chile where copper is common. The sulfuric acid is extremely dangerous and leaks into the water supplies, because they don't have very good regulations in place to filter to mine runoff. 3) I used to live in central Illinois where farming is the major industry. One of the big problems there is that sediment and fertilizer from the fields ends up

running off into streams and ponds. A lot of the nutrients eventually end up in the Mississippi River and the Gulf of Mexico, which has caused some major problems. Something that they have started to do around the larger farms is putting in sedimentation ponds. Basically, once the water flows off of the field, it goes into the pond instead of the drainage pipes. The ponds aren't anything big. They just cover a relatively small area, but they work great from what I have been told. They have done a few studies and found that almost all of the nutrients and sediment gets filtered out in the pond so that only clean water ends up in the pipes. i think it is a great method of erosion and sediment control, and they should be more common. @cardsfan27 - A silt fence is a pretty common structure on most construction sites that are located on hilly areas. Basically, it is a black tarp-looking material that is put up like a fence around the building area. They work all right for temporary uses. They don't really filter anything like a pond would. Their main use is just to physically stop sediment from moving downhill. 2) For any construction project, they should have permits in place to do whatever they are doing. You could check with the city and see that they have the right permits. If the stream is a small one, the city probably makes its own regulations about what can and can't go into it. If it is a larger one, though, it make be regulated by the EPA. I wouldn't go snooping around the construction site, though, looking for these things. I'm sure the workers wouldn't appreciate that much. - jmc88 1) How exactly would you identify a silt trap if it were in place? I guess I could see the silt pond, but what would a silt fence look like? How effective are these things at actually stopping the silt from entering the water supply? I ask because there is a construction project going on in our town, and I get the feeling that the workers are not using the proper methods to stop material from getting into the stream that is nearby. I would like to get an idea of whether or not they are doing things the way they are supposed to. If they were violating the regulations, who would you call to report something like that? Would it be an issue that the city was supposed to take care of, or would that be something for a larger organization like the state or national EPA? Silt fence

A silt fence, sometimes (misleadingly) called a "filter fence,"[citation needed] is a temporary sediment control device used on construction sites to protect water quality in nearby streams, rivers, lakes and seas from sediment (loose soil) in stormwater runoff. Silt fences are widely used on construction sites in North America and elsewhere, due to their low cost and simple design.[1] However, their effectiveness in controlling sediment can be limited, due to problems with poor installation, proper placement, and/or inadequate maintenance.[2] Silt fences are often perimeter controls, typically used in combination with sediment basins and sediment traps, as well as erosion controls, which are designed to retain sediment in place where soil is being disturbed by construction processes (i.e., land grading and other earthworks). A typical fence consists of a piece of synthetic filter fabric (also called a geotextile) stretched between a series of wooden or metal fence stakes along a horizontal contour level. The stakes are installed on the downhill side of the fence, and the bottom edge of the fabric can be trenched into the soil and backfilled on the uphill side, although it is quite difficult to move the trenched "spoil" from the downside to the upside of the trench. The design/placement of the silt fence should create a pooling of runoff, which then allows sedimentation to occur. Water can seep through the silt fence fabric, but the fabric often becomes "blocked off" with fine soil particles (all sediment-retention devices have this challenge, and none of them "filter" storm water for very long).[citation needed] A few hours after a storm event, the fabric can be "disturbed" in order to dislodge the fines, and allow clean water to flow through. Depending on the protected watershed and erosion, larger soil particles will settle out, ultimately filling the silt fence to the top of the structure; requiring another silt fence above or below it (creating a new ponding area), or for the silt fence to be removed, the sediment removed or spread out, and a new fence installed. The fence is not designed to concentrate or channel stormwater. The fence is installed on a site before soil disturbance begins, and is placed down-slope from the disturbance area. Sediment is captured by silt fences primarily through ponding of water and settling, rather than filtration by the fabric. Sand and silt tends to clog the fabric, and then the sediments settle in the temporary pond.[6]:p.6–9 [7]:p.7–46 Some government jurisdictions in the United States recommend or require the use of a reinforced fence, sometimes called a "super" silt fence or an enhanced silt fence, on some construction sites. This design uses filter fabric reinforced by a wire mesh or chain link fence. The metal backing gives the fence increased strength to resist the weight of soil and water which may be trapped by the fence in a large drainage area, and discourages construction site operators from driving vehicles over the fence.[8] However, an improper installation of a super silt fence can create an inadvertent sediment basin

when the filter fabric becomes clogged. This typically causes flooding and increased downstream pollution. Most super silt fence specifications are outdated, requiring the trenching installation method, which has been shown to be highly susceptible to "washing out" under the fabric due to improper back-filling and inadequate compaction.[citation needed] Silt fence fabrics (geotextiles) tested in laboratory settings have shown to be effective at trapping sediment particles.[11]:45–47 Although there have been few field tests of silt fences installed at construction sites, these tests have shown generally poor results.[11]:27–31, 53–55 (Effectiveness testing involved measurements for both total suspended solids and turbidity.) Other studies and articles about silt fence usage and practice document problems with installation and maintenance, implying poor performance.[12] Since 1998, static slicing the material into the ground has proven to be the most efficient and most effective installation method because slicing maintains the soil on both sides of the fence, and is conducive to proper compaction—which is critical to performance, as well.[citation needed] In 2000 the U.S. Environmental Protection Agency (EPA) co-sponsored silt fence efficacy field research through its Environmental Technology Verification Program, and in general, the report found the static slicing method to be highly effective, and efficient.[13] Silt fence effectiveness is best determined by how many hundreds of pounds of sediment are contained behind a given silt fence after a storm event, and not turbidity, etc. as sediment-retention is the end goal, and not a water-quality measurement used in erosion control, for instance.[citation needed] Silt fences may perform poorly for a variety of reasons, including improper location (e.g. placing fence where it will not pond runoff water), improper installation (e.g. failure to adequately embed and backfill the lower edge of fabric in the soil) and lack of maintenance—fabric falling off of the posts, or posts knocked down. A silt fence top-full of sediment may need maintenance/replacement, but it is a huge success.[6]:p.6–10 The fabric may become damaged with holes and tears if construction materials are stored next to or on top of the fence. During various phases of construction at a site, a silt fence may be removed relocated and reinstalled multiple times. [11]:30–31 It may be difficult to maintain effectiveness of a silt fence under such operating conditions. Location of fences in areas with high flows may lead to fence failures when the installation is not adequately back-filled and properly compacted, and/or the post-spacing is inadequate.[7]:p.7–46 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. Sediment basins are

typically used on construction sites of 5 acres (20,000 m2) or more, where there is sufficient room. They are often used in conjunction with erosion controls and other sediment control practices. On smaller construction sites, where a basin is not practical, sediment traps may be used.[1] Essential sediment abundance is prevalent in the construction industry which gives insight to future endeavors. In essence lateral buckling occurs under traverse load or at critical loads. On some construction projects, the sediment basin is cleaned out after the soil disturbance (earth-moving) phase of the project, and modified to function as a permanent stormwater management system for the completed site, either as a detention basin or a retention basin.[2] A sediment trap is a temporary device installed 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 trap is basically an embankment built along a waterway or low-lying area on the site. They are typically installed at the perimeter of a site and above storm drain inlets, to keep sediment from entering the drainage system. Sediment traps are commonly used on small construction sites, where a sediment basin is not practical. Sediment basins are typically used on construction sites of 5 acres (20,000 m2) or more, where there is sufficient room.[3] Sediment traps are installed before land disturbance (earth moving, grading) begins on a construction site. The traps are often used in conjunction with erosion controls and other sediment control practices.[4]