Appendix 1 SESC Best Management Practices Guidance Sheets

Appendix 1 Sesc Best Management Practices Guidance Sheets-Free PDF

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SESC BMP Contents,Silt Fence I 3,Turbidity Curtain I 7. Storm Sewer Inlet Protection I 12,Access Road I 18. Check Dam I 24,Riprap Stabilized Outlet I 30,Rolled Erosion Control Products I 41. Diversions I 49,Sediment Basin I 54,Mulching I 65,Hyrdoseeding I 69. Dust Control I 73,Polyacrylamide PAM I 78,Appendix I 2.
Silt Fence,Definition, Silt fence is a perimeter sediment control device Generally silt fence is. constructed of porous woven geotextile fabric attached to wooden posts. Description and Purpose, Silt fence is a linear fence installed at the edge of earth disturbances The purpose. of silt fence is to protect downslope surface waters and properties by removing. suspended solids from runoff prior to leaving the site. The practice may also be called filter fence,Pollutant s controlled. Suspended solids,Treatment Mechanisms, Slowing and ponding of runoff water to promote settlement of suspended. Fabric provides some filtration of larger soil particles. Pollution Removal Efficiencies, Moderate to good removal of silt and sand particles if properly placed.
installed and maintained,Poor removal of clay particles. Companion and Alternative BMPs,Perimeter Controls Page BMP Guidebook. Storm Sewer Inlet Protection,Advantages and Disadvantages. Advantages,Relatively inexpensive,Easy to install,Readily available. Disadvantages, Poor effectiveness on fine sized soil particles such as clay.
May require frequent maintenance, Effective only for sheet runoff flow fails in concentrated flow areas due to. low permeability,Limited effectiveness at large sloping sites. Silt fence should be installed at the downslope edge of disturbed areas along a line. Appendix I 3, of equal elevation parallel to contour lines Place beyond the toe of steeper. slopes if possible to increase the ponding or settling effect. Table 1 Materials and properties for silt fence construction. Woven Min Min Grab Trapezoidal Min Max Apparent, Geotextile Hardwood Tensile Tear Strength Permittivity Opening Size. Fabric Post ASTM D ASTM D ASTM D ASTM D,Width Length 4632 4533 4491 4751.
24 36 100 lbs 45 lbs 0 1 sec 1 0 6 mm,36 48 100 lbs 45 lbs 0 1 sec 1 0 6 mm. Hardwood posts shall be a minimum of 1 1 8 x 1 1 8 thickness. Source Adapted from Michigan Department of Transportation 2003 Standard. Specifications for Construction,Additional materials. Metal Staples or nails for attaching lath and fabric to posts. Hardwood Lath 6 to 8 inches shorter than fabric width. Design Specifications, Fabric attached to post by stapling or nailing through lath and into hardwood. posts at a minimum of four locations evenly spaced along lath to prevent fabric. 6 inch loose bury flap unattached to post at bottom of lath. Maximum post spacing 10feet, Whenever possible place silt fence in flat areas at least 10 feet from the toe of. slopes silt fence is not an appropriate measure for placement on steep slopes. Maximum contributing drainage area is acre per 100 linear feet of fence. Performance Enhancers, Wider Fabric and longer posts ie 36 fabric and 48 posts.
Heavier posts ie 2 x 2,More frequent post spacing ie 6 5. Reinforcing mesh on fabric, Placing multiple parallel rows may provide a factor of safety. Construction Guidelines,Guidelines are in consecutive order. 1 Dig a 6 inch trench at equal elevation parallel to contour lines at the. downslope edge of earth disturbance avoid placement on steep slopes. 2 Unroll and extend silt fence along trench line Orient fence such that the posts. are down slope of the fabric and lath ie storm water will push the lath and. fabric against the post, 3 Turn end post 360 degrees so that fabric surrounds the post. Appendix I 4, 4 Pound end post into the ground at the downslope edge of the trench until the.
top of the 6 bury flap is at ground elevation, 5 Continue to pound in posts consecutively starting with post adjacent to the end. already installed Assure fabric is as taught as possible. 6 Join consecutive rolls by rolling end posts similar to Item 3 above Cross over. the end posts or place them side by side and roll them 180 or 360 degrees. Drive the end posts together, 7 Backfill the trench and compact If possible leave a compacted ridge of soil. along the upslope edge of the fabric,Alternative Construction. 1 In situations where the bury flap cannot be trenched in backfill and compact. over the bury flap note less effective and more prone to failure. 2 In some cases it may be advantageous to construct silt fence in the field i e. fabric posts and lath come separate and must be put together The same. construction guidelines apply, 3 Silt fence installation machines may make the process of installing silt fence. easier The machines slice the fabric into the ground then posts and lath are. manually installed,Monitoring, Silt Fence should be inspected at least weekly immediately before a forecasted.
runoff event and after each runoff event from rain or snowmelt Look for fabric. tears post failure undermining sediment build up overtopping side cutting. around the silt fence and areas damaged by construction activities. Maintenance, Fabric tears post failures vehicle damage and or undermining should be. repaired immediately, Sediment build up should be removed when it reaches 1 3 to 1 2 the height of. the silt fence above ground elevation, Overtopping and side cutting are signs that the silt fence is either not. appropriately placed or that additional measures are necessary due to site runoff. conditions, REMOVE THE SILT FENCE ONCE THE SITE IS STABLIZED WITH PERMANENT. SESC MEASURES,References, Michigan Department of Transportation 2003 Standard Specifications for.
Construction, Oakland County Michigan Water Resources Commissioner Individual Soil Erosion. and Sedimentation Details SP 2 Silt Fence,Appendix I 5. Exhibit 1 Silt fence construction and installation diagram. SPACING 10 MAX, Source Adapted from Oakland County Michigan Erosion Control Manual. Appendix I 6,Turbidity Curtain,Definition, A flexible impermeable barrier used to trap sediment in water bodies This curtain. is generally weighted at the bottom to ensure that sediment does not travel under. the curtain which is supported at the top through a flotation system Staked. curtains are available for applications with very limited exposure to water flow or. wave action,Description and Purpose, To prevent the migration of sediment from a work site in a water environment into.
the larger body of water, The practice may also be called turbidity barrier silt curtain. Pollutant s controlled,Suspended Solids,Treatment Mechanisms. Advantages and Disadvantages,Advantages, Allows for containment of sediment laden water within a work area. Protects contained water from turbulence allowing particles to fall out of. suspension,Disadvantages, Can fail when subjected to significant water flows or wave action. Cannot be used as a filter across stream flow, Possible mobilization of fine sized settled particles after removal.
A turbidity curtain is generally used when construction activity occurs within a. waterbody or along its shoreline and is of short duration generally less than one. month Curtains are used in calm water surfaces Turbidity curtains are not to. be used across flowing watercourses,General Characteristics. Turbidity curtains should be oriented parallel to the direction of flow. For sites not subject to heavy wave action the curtain height shall provide. sufficient slack to allow the top of the curtain to rise to the maximum. expected high water level including waves while the bottom maintains. continuous contact with the bottom of the water body The bottom edge of. Appendix I 7, the curtain shall have a weight system capable of holding the bottom of the. curtain down and conforming to the bottom of the water body so as to. prohibit escape of turbid water under the curtain, For sites subject to heavy wave action the curtain height shall provide. sufficient slack to allow the top of the curtain to rise to the maximum. expected high water level including waves while the bottom remains 1 foot. above the bottom The weight system shall hold the lower edge of the. curtain in place so as to allow 1 foot of clearance above the bottom at mean. low water so that the curtain does not stir up sediment by repeatedly. striking the bottom, The curtain should be constructed of nonwoven material. Materials should be of bright colors when applicable to attract attention of. boaters or swimmers using areas near the work site. Rope or cable with floats, Premanufactured Turbidity Barrier generally woven geotextile with polymer.
Design Specifications, The turbidity curtain shall be located beyond the lateral limits of the. construction site and firmly anchored in place, The alignment should be set as close to the work area as possible but not so. close as to be disturbed by construction equipment. The height of the curtain should be designed to account for expected wave. action and water level fluctuations as a result of storm events At a. minimum the curtain height should be 20 percent greater than the depth of. The area that the turbidity curtain protects shall not contain large culverts or. drainage outlets which may cause the curtain to fail during flow events. If water depths 2 feet and flow at the designed alignment is minimal the. toe can be anchored in place by staking Exhibit 1 Shallow. When water is greater than 2 feet deep or where high flow exists the. Turbidity Curtain Deep design must be used Exhibit 1. Hard armor ie concrete barriers may be necessary to protect the curtain. on the upstream side in certain flowing water applications. Construction Guidelines, 8 Assure that all necessary permits for work within a water of the state are. obtained from the DEQ Water Resources Division prior to starting work. 9 The area of proposed installation of the curtain shall be inspected for obstacles. and impediments that could damage the curtain or impair its effectiveness to. retain sediment, 10 All construction materials shall be removed so they cannot enter the water body. Appendix I 8, 11 Shallow installations can be made by securing the curtain by staking rather than.
using a flotation system, 12 Supplemental anchors of the turbidity curtain toe shall be used as needed. depending on water surface disturbances such as boats and wave action by. Monitoring, 1 The turbidity curtain shall be inspected daily and repaired or replaced. immediately, 2 If the curtain is oriented in a manner that faces the prevailing winds frequent. checks of the anchorage shall be made, 3 While inspecting look for areas where turbid water is escaping into the larger. water body,Maintenance, It is not normally necessary to remove sediment deposited behind the curtain.
but when necessary removal is usually done by hand prior to removal of the. barrier All removed silt is stabilized away from the water body. The barrier shall be removed by carefully pulling it toward the construction site. to minimize the release of attached sediment, Any floating construction or natural debris shall be immediately removed to. prevent damage to the curtain,References, Michigan Department of Transportation 2006 Soil Erosion Sedimentation Control. Manual Michigan Department of Management and Budget 2003 Soil Erosion and. Sedimentation Control Guidebook,Appendix I 9,Turbidity Curtain. Appendix I 10, Source Adapted from Michigan Department of Transportation 2006 Soil Erosion. Sedimentation Control Manual and Michigan Department of Management and. Budget 2003 Soil Erosion and Sedimentation Control Guidebook. Appendix I 11,Storm Sewer Inlet Protection,Definition.
Storm sewer inlet protection consists of a sediment filter or an impounding area. around or upstream of a storm sewer drop inlet or curb catch basin. Description and Purpose, Storm sewer inlet protection measures temporarily pond runoff before it enters the. storm sewer allowing sediment to settle or remove sediment by filtering. The practice may also be called Storm Sewer Inlet Protection or Inlet Protection. Pollutant s controlled,Suspended Solids,Treatment Mechanisms. Settling of sediment through detention,Filtration of sediment. Pollution Removal Efficiencies, Varies with soil type on site and type of inlet protection selected. Companion and Alternative BMPs,Silt fence,Sediment basins.
Advantages and Disadvantages,Advantages, Will reduce the amount of sediment entering the storm sewer system. potentially extending the time until maintenance is needed. In many cases provides a last chance to remove suspended particles from. Areas requiring protection are easy to identify during both planning and. construction,Disadvantages, Requires an adequate area for water to pond without encroaching into. portions of the site where active construction is occurring or onto roadways. subject to traffic, Inlet protection usually requires other methods of temporary protection to. prevent sediment laden storm water and non storm water discharges from. entering the storm sewer system, Sediment removal may be difficult in high flow conditions or if runoff is. heavily sediment laden,Frequent maintenance is required.
Table 1 Materials and properties for silt fence construction Woven Geotextile Fabric Width Min Hardwood Post Length Min Grab Tensile ASTM D 4632 Min Trapezoidal Tear Strength ASTM D 4533 Min Permittivity ASTM D 4491 Max Apparent Opening Size ASTM D 4751 24 36 100 lbs 45 lbs 0 1 sec 1 0 6 mm 36 48 100 lbs 45 lbs 0 1 sec 1 0 6 mm Hardwood posts shall be a minimum of 1 1 8

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