Erosion And Sediment Control Design Guide
Erosion and Sediment ControlDesign Guide2020 Edition
Erosion and Sediment Control Design GuideTable of ContentsIPREFACE . IIIVERSION HISTORY . II1.0 INTRODUCTION . 1‐12.0 EROSION, SEDIMENT, AND STORMWATER MANEGEMENT (ES2M) PROGRAM . 2‐13.0 EROSION AND SEDIMENT CONTROL STRATEGY. 3‐14.0 EROSION AND SEDIMENTATION PROCESS . 4‐15.0 DEVELOPING THE EROSION AND SEDIMENT CONTROL PLAN . 5‐16.0 SITE ASSESSMENT . 6‐17.0 GENERAL PRINCIPLES FOR AN EFFECTIVE EROSION AND SEDIMENT CONTROL PLAN . 7‐18.0 EROSION AND SEDIMENT CONTROL DESIGN GUIDELINES . 8‐18.1 SEDIMENT TRAPPING DEVICES . 8‐28.1.1 SILT FENCE, REINFORCED SILT FENCE, SUPER SILT FENCE . 8‐38.1.2 SEDIMENT BASIN/TRAP . 8‐58.1.3 INLET SEDIMENT CONTROL, DRAINAGE INLET/CURB INLET/CULVERT INLET . 8‐108.2 DEWATERING PRACTICES . 8‐138.2.1 PORTABLE SEDIMENT TANK . 8‐148.2.2 SUMP PIT . 8‐158.2.3 SKIMMER DEWATERING DEVICE . 8‐168.3 WATER CONTROL PRACTICES . 8‐178.3.1 CHECK DAM . 8‐188.3.2 TEMPORARY SLOPE DRAIN . 8‐208.4 SOIL STABILIZATION PRACTICES . 8‐218.4.1 VEGETATIVE STABILIZATION . 8‐22
Erosion and Sediment Control Design Guide8.4.2 STABILIZED CONSTRUCTION ENTRANCE . 8‐248.5 WATERWAY CONSTRUCTION PRACTICES . 8‐268.5.1 STILLING WELL . 8‐278.5.2 SANDBAG DIKE . 8‐288.5.3 SANDBAG DIVERSION . 8‐308.5.4 CHANNEL DIVERSION . 8‐328.5.5 TURBIDITY CURTAIN . 8‐348.6 POLLUTION PREVENTION PRACTICES . 8‐368.6.1 CONCRETE WASHOUT. 8‐379.0 REFERENCES . 9‐110.0 GLOSSARY . 10‐1
Erosion and Sediment Control Design GuideIPREFACEThis document provides guidelines for the design of erosion and sediment control practices for DelDOTconstruction projects. It was developed to provide a convenient resource for the analysis and design oferosion and sediment control measures for Erosion and Sediment Control Plans. The guide is intendedprimarily for use by designers but also provides valuable information for contractors and field personnel.Although it will provide direction in the analysis and design of standard erosion and sediment controlpractices, it does not preclude innovative or alternative designs as approved by the Stormwater Engineer.This design guide is intended to be a living document subject to periodic updates and revisions in responseto user feedback, changes in technology, and revisions to regulatory requirements. Inquiries andcomments may be sent to the DelDOT Stormwater Engineer. The most current version of this documentis located on the Department’s website: https://deldot.gov/Business/drc/index.shtml?dc stormwater.I
Erosion and Sediment Control Design GuideIIVERSION HISTORYVersion No.N/ADateApril 2020DescriptionInitial ImplementationII
Erosion and Sediment Control Design Guide1.0 INTRODUCTIONSoil erosion is a naturally occurring process by which the land’s surface is worn away by the action of wind,water, ice, and gravity. This natural and geologic erosion has been occurring at a relatively slow rate sincethe Earth was formed and it has been a tremendous factor in shaping our planet as we know it today.Both the rolling hills of the Piedmont and the broad expanse of the Coastal Plain are a result of the geologicerosion and sedimentation process in Delaware. Although geologic erosion is vital for maintainingenvironmental balance, construction activities can result in accelerated rates of erosion andsedimentation where soil surfaces are initially not revegetated. Vegetated cover plays a key role incontrolling erosion as it shields the soil surface from raindrop impact, provides a root system to hold soilparticles in place, maintains the soil’s capacity to absorb water, reduces runoff velocity, and removessubsurface water between storm events through the process of evapotranspiration. If bare soil surfacesare left non‐vegetated, the loss of these processes may result in an adverse impact to the environment,such as degradation of surface water quality, damage to adjacent land, and deterioration of aquatichabitat.Erosion and sediment control (E&S) measures are activities, practices, or a combination of practicesdesigned to protect an exposed soil surface, to prevent or reduce the release of sediment toenvironmentally sensitive areas, and to promote revegetation as soon as possible. The purpose of thisdocument is to provide design guidelines and considerations so that construction and maintenanceactivities are carried out in a manner to minimize erosion and sediment transport, particularly where thereare potential impacts to environmentally sensitive areas.The objectives of this guide include the following: Provide guidelines and procedures for selecting and designing erosion and sediment controlmeasures for Department projects.Provide a platform to assist with educating designers and construction personnel on erosionand sediment control design and analysis.1‐1
Erosion and Sediment Control Design Guide2.0 EROSION, SEDIMENT, AND STORMWATER MANAGEMENT(ES2M) PROGRAMNPDES Permit ProgramThe Clean Water Act of 1972 gave the Environmental Protection Agency (EPA), and states which havedelegated authority by the EPA, the power to regulate point sources that discharge pollutants into watersof the United States through the National Pollutant Discharge Elimination System (NPDES) permitprogram. Point sources are generated from a variety of municipal and industrial operations, includingtreated wastewater, process water, cooling water, and stormwater runoff from drainage systems. TheNPDES permit program helps ensure that Delaware’s water bodies can meet their designated uses, suchas providing safe drinking water, being safe for swimming and fishing, and supporting aquatic life. In 1987,amendments to the Clean Water Act were passed that allowed the EPA to regulated non‐point sources,which includes stormwater runoff from construction sites.The NPDES permit limits the discharge of pollutants to protect the waters that receive them. The healthof a water body is measured by the attainment of its designated uses. For example, pollutants in awaterbody are considered to be eliminated once the potential pollutants in an NPDES discharge have beenreduced to levels that allow the receiving waters to meet their designated uses.Delegation AuthorityManagement of the NPDES permit program, except for pre‐treatment and federal facilities, is delegatedto the Department of Natural Resources and Environmental Control (DNREC) under Section 402 of theClean Water Act and State Law. The Program is managed by DNREC Division of Water under the SurfaceWater Discharges Section. The Sediment and Stormwater Program, managed by DNREC Division ofWatershed Stewardship, provides oversight of the statewide NPDES permit program regardingstormwater management and erosion and sediment control. Within its purview, DNREC has the authorityto delegate the implementation of the statewide sediment and stormwater program to conservationdistricts, counties, municipalities, and other state agencies. The Department has delegation of DNREC’sSediment and Stormwater Program elements. These elements are comprised of stormwatermanagement and Erosion and Sediment Control (E&S) Plan review, construction inspection, andmaintenance inspection for all Department projects.Department OversightDelaware’s Erosion and Sediment Control Program is regulated by Chapter 40 (Erosion and SedimentControl) of Title 7 (Conservation) of the Delaware Code. Under this law, the Department must ensure thatall Erosion and Sediment Control Plans adhere to the Delaware Sediment and Stormwater Regulations(DSSR).2‐1
Erosion and Sediment Control Design GuideEPANPDESStormwater ProgramStormwaterGeneral Permits(7 Del. C. Chapter 60)DNRECDivision of WaterSurface WaterDischarges SectionDNRECDiv. of Watershed StewardshipSediment and Stormwater (7 Del.C. Chapter 40)DelDOTStormwaterE&SNPDESConstruction Activities& MaintenanceConstructionNPDES Stormwater Program Management Oversight Flowchart2‐2
Erosion and Sediment Control Design Guide3.0 EROSION AND SEDIMENT CONTROL STRATEGYDepartment RequirementsThe Department requires that the E&S Plan be prepared by experienced individuals or firms. It is theexpectation that the contractor will perform the construction work in conformance with the approvedplan. Designers, contractors, and construction reviewers are required to meet various responsibilitiesconcerning environmental protection in order to ensure that the project design and delivery is incompliance with applicable environmental laws and regulations.Designer ResponsibilityThe designer has the responsibility to prepare the E&S Plan for the project. This plan is provided to thecontractor to implement approved erosion and sediment control measures. It is required that the E&SPlan be prepared by or under the supervision of a licensed Delaware Professional Engineer who isexperienced with designing erosion and sediment controls for Department projects. The plans must alsobe signed and sealed by a licensed Delaware Professional Engineer. In addition, it is strongly encouragedthat the designer visit the site prior to or while developing the E&S Plan to see firsthand any unique sitefeatures that may lead to erosion during construction, but which may not be easily recognizable based onfield survey or desktop information alone. Once the plan has been submitted for review, the designer willbe responsible for addressing any deficiencies prior to approval from the Stormwater Engineer.Contractor ResponsibilityThe contractor has the responsibility to ensure that all erosion and sediment control measures be installedand functioning as intended according to the approved E&S plan, Standard Construction Details, andStandard Specifications. The contractor must also repair or replace any damaged erosion and sedimentcontrols, address site deficiencies, and notify the E&S Engineer of areas where additional erosion andsediment controls may be required but not included on the approved E&S Plan. The Contractor mayamend the approved E&S Plan per the approval of the E&S Engineer.E&S Reviewer/Certified Construction Reviewer (CCR) ResponsibilityThe E&S Inspector or CCR has the responsibility to report on contractor adherence to the approved E&SPlan by coordinating with the Department, designer, and contractor. The reviewer is also responsible forconducting weekly E&S inspections, preparing inspection reports, and attending preconstruction andprogress meetings. Rain event E&S inspections are required on projects that have a Notice of Intent (NOI).Other duties may include performing and documenting vegetative evaluations, water quality and soilsampling/testing, and stormwater facility construction. The CCR shall function under the direction of alicensed Delaware Professional Engineer.3‐1
Erosion and Sediment Control Design Guide4.0 EROSION AND SEDIMENTATION PROCESSErosionErosion is a geological process in which earthen materials are worn away by naturally occurring agentsthrough the detachment and transport of soil materials from one location to another, usually at a lowerelevation. Natural agents such as wind and water are primarily responsible for this phenomenon but theextent to which erosion occurs can be considerably accelerated by construction activities. Although winderosion is a common occurrence on construction projects, water is the predominant agent of erosion andsediment transport. As a result, methods of limiting water erosion and sediment transport will be theprincipal focus of this design guide.TypesThe four types of erosion that result from water include raindrop, sheet, rill and gully, and stream andchannel.Raindrop ErosionSheet ErosionRill and GullyErosionStream andChannel ErosionSee Appendix for image sources1. Raindrop (splash) erosion is the movement of soil particles caused by the direct impact ofraindrops on unprotected exposed soil surfaces.2. Sheet erosion is the movement of soil particles by runoff flowing over the ground surface as anunconcentrated thin sheet layer. Erosion is caused by shear stresses associated with water flow.3. Rill and gully erosion are the movement of soil particles due to the concentration of runoff indepressions (rills) in the ground surface. The erosion potential is significantly greater than sheetflow due to the increased velocity and flow depth. Additional increases in velocity and flow depthfurther increase the erosion potential which may gradually enlarge the rills into gullies.Depressions or channels with a depth of 4‐inches or less are considered rills. These channels runparallel to each other but may converge at some points. Once the channel depth exceeds 4‐inches, they begin to form gullies where the width, depth, and flow strength become much moresignificant.4. Stream and channel erosion are the movement of soil particles on the bed and banks of streamsand channels due to concentrated runoff. Scouring, another facet of channel erosion, occursalong channels where eddies form as a result of sudden expansion, contraction, or change in flowdirection. Scouring may lead to rapid soil loss from the channel bed or side slopes.4‐1
Erosion and Sediment Control Design GuideTypes of Water ErosionFactors Affecting ErosionErosion occurs as a result of several interacting factors and processes. The four main factors thataffect erosion are: ClimateSoilVegetationTopographyClimateAlthough the regional climate remains relatively consistent throughout the state, storm event durationand intensity may vary for a given return period based on the location of the project site. Rainfall eventsof greater duration and intensity are more likely to increase the potential for erosion on any given site.The climate of a location indirectly determines the amount of annual precipitation, the length of thegrowing season, and other factors that affect plant growth and the extent of vegetative cover. In addition,the climate may have a long‐term effect on topography, especially in reference to wind eroded gullyformation in certain areas of the state. Soil characteristics are also affected by climate. Arid terrain withintermittent intense rainfall events can lead to erosive environments.4‐2
Erosion and Sediment Control Design GuideSoilSoil characteristics that have been identified as primarily affecting soil erodibility are particle sizedistribution and texture, cohesiveness, permeability, and fibrous organic matter content. In general, soilscontaining high proportions of silt and very fine sand are usually the most erodible. Erodibility typicallydecreases as the cohesiveness of the soil increases. However, once eroded, clays are easily transported.Well‐graded gravel and predominantly gravel mixtures with trace amounts of silt are the least erodiblesoils. The ability of soil to absorb rainfall or surface runoff is best characterized by its permeability. Thepotential for erosion is reduced if the soil tends to absorb rainfall or surface runoff as this decreases thevolume of water available to cause sheet or rill and gully erosion. However, after a prolonged period ofhot and dry weather, there may be a lag time between the onset of rainfall and the start of infiltrationdue to the unsaturated nature of the exposed surface soils. In this event, the initial amount of runoff maybe significant. Overall, topsoil can be effective in reducing or preventing erosion due to its permeabilityand fibrous nature of its organic material.VegetationIn nature, the extent of vegetative cover largely determines the level of erosion that takes place on land.Vegetative cover is a very durable and highly effective erosion control measure. It achieves its objectiveby shielding the ground from direct rainfall impact, improving soil permeability, reducing runoff velocity,and holding soil particles in place with a root structure from living and dead vegetation (topsoil). Becausevegetative cover is so effective in controlling soil erosion, it is usually the primary choice for long‐termerosion control.TopographyTopography refers to the shape, length, inclination, and aspect of a slope. The length and inclination arecritical factors with longer and steeper slopes producing greater soil erosion. Slope also affects soilerosion. For example, in Delaware, south‐facing slopes tend to dry faster and have a better growingregime than north‐facing slopes since slopes on the south side tend to receive more direct sunlight. Theshape of a slope also influences the potential extent of erosion. Concave slopes with less inclination atthe base are generally less erodible than convex slopes.4‐3
Erosion and Sediment Control Design GuideSedimentation is the deposition of soil particles previously held in suspension by flowing water. Thephenomenon of sedimentation occurs at those locations experiencing a reduction in flow velocity.Initially, the larger particles settle out and, as the flow velocity continues to decrease, the smallerparticles settle, eventually leaving only the clay sized particles. These particles are the smallest andthe last to be deposited. Sedimentation can also occur in slow
Erosion and Sediment Control Design Guide 4‐1 4.0 EROSION AND SEDIMENTATION PROCESS Erosion Erosion is a geological process in which earthen materials are worn away by naturally occurring agents
outline the principles of erosion and sediment control, give guidelines to minimise erosion and sedimentation for plantation forestry and provide specifications and standards for erosion and sediment control practices. They replace the July 2000 Erosion and Sediment Control Guidelines for Forestry Operations. We need guidelines because: 1.
WATERSHED MANAGEMENT ORDINANCE TECHNICAL GUIDANCE MANUAL 5/26/2020 4.1 GENERAL SOIL EROSION AND SEDIMENT CONTROL REQUIREMENTS PAGE 4-2 4.1 GENERAL SOIL EROSION AND SEDIMENT ONTROL REQUIREMENTS §400.1 of the WMO requires erosion and sediment control practices for all projects, rega
Mar 07, 2020 · Chapter 7 - Erosion and Sediment Control Section 7D-1 - Design Criteria 2 Revised: 2013 Edition B. Erosion Control The key to successful erosion and sediment control on construction sites is the prevention of erosion. The simplest way to keep sediment from
A number of east coast jurisdictions have sediment and erosion control manuals which address factors influencing erosion and sedimentation. The following is reproduced from the “1983 Maryland Standards and Specifications for Soil Erosion and Sediment Control”, (Reference 1).
NDDOT Erosion & Sediment Control - Construction Course Wind Erosion and Deposition 29 Erosion Facts (USDA NRCS Soil Quality - Urban Technical Note No. 1 "Erosion and Sedimentation on Construction Sites") Construction sites can erode at a rate of 100 to 500 tons/acre/year 100 times greater than cropland 2,000 times greater than woodlands 30
Erosion is the detachment and movement of soil particles by wind, water, and gravity. Natural erosion (geologic erosion) is a process that occurs slowly over millions of years. Geologic erosion has shaped the landscape around us. Accelerated erosion is NOT
CONTENTS Erosion and Sediment Control Principles 4 Kerbside Turf Strip (SD 6-13) 28 Standard Erosion and Sediment Control Symbols (ES 01) 5 Stabilised Site Access (SD 6-14) 30 . Lay rock following the drawing and according to table 5.2 of Landcom (2004; pg 5-24) and with a minimum size of Ø70mm 4. Ensure that any concrete or riprap used for .
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