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BMP Regulatory ComplianceBMP Selection for Regulatory 0 Compliance A proposed method for assessing and classifying current construction and postconstruction, structural best management practices. By David Woelkers and Marc S. Theisen ith the onset of the National Pollutant Discharge Elimination System Phase II stormwater rule requirements for con- struction and postconstruction best management practices (BMPs), profes- sionals, contractors, and end users are struggling to develop a systematic and logical method for se- lecting the appropriate BMPs to be integrated into the various construction phases of their projects. Currently, widespread confusion exists regarding selection of the best options for a particular site. As a result, many projects end up with inappro- priate BMPs for the applications and iissues that they are at- tempting to deal with. This article offers planners a proposed method for classifying BMPs and a process for selecting the most appropriate and cost - effective B'VIPs for their particular projects. Most regulators have two primary concerns that underlie stormwater requirements in the site -plan approval processes. These are the control of water quantity and treatment for quality both during and after the active construction phase. Water - quantity outputs from sites generally are limited to pre - development levels. Water -quality issues focus on reducing contaminants from runoff prior to their discharge from the site. Sediment is the most prevalent constituent of concern for receiving waters. Other problematic constituents typically in- clude nutrients, metals, hydrocarbons and other organic com- pounds, and bacteria. As a result, each site must be analyzed to determine specific application needs. Understanding what types of structural BMPs are available and how they interact with one another will help provide guidance in selecting the right mix for a specific site. According to EPAs Preliminary Data Summary of Urban Stormwater Best Management Practices, an urban storrrrwater BMP is a "technique, measure or structural control that is used for a given set of conditions to manage the quantity and im- prove the quality of storm water runoff in the most cost- effec- tive manner." With ongoing research, new BMPs are constantly emerging. In fact, the term "best management practices" would be more accurately phrased as "better management practices" because what is "best" varies with each application. To ensure maximum benefit is achieved, planners should assess and evaluate various BMPs for the pre construction, ac- tive constniction, and postconstruction phases to make sure their plans are approved in a timely and cost - effective manner and that they include the most appropriate BMPs for a specif- ic application. Phases of Construction Preconstruction The preconstruction phase requires a careful assessment of the specific site. The first step is to gain a clear understanding of what stormwater controls will be required by relevant stormwater regulations, local ordinances, and site -plan ap- proval processes. Nearly all regulations will require controls during the active construction phase to control sediment and limit runoff from the site to ensure minimum impacts on downstream receiving waters. The primary construction con- cern is sediment control, and a wide range of both temporary and permanent BMPs will be needed. Each application must be examined to determine site- specific needs for laying out the sequence of selecting both temporary and permanent BMPs. This sequence is commonly referred to as the "treat- ment train," and a clear understanding of all available options is critical for a successful site plan. Several factors must be considered in devising an effective classification of BMPs to assist planners and end users in the assessment and selection process. First is the proposed land use of a project. Possible uses include industrial, commercial, residential, and streets and highways. For each use, the specif- ic site application needs must be determined. Consideration should be given to whether the project is new or redevelop- ment and how much land will be available for BMP installa- tions. A detailed review of receiving -water concerns, along www.stormh2o.com with an analysis of the site's potential to generate pollutants of concern both during and after construction, also must be completed prior to BMP selection. Once a review of the land use and receiving -water con- cerns is completed, an assessment of the appropriate BMP op- tions can be evaluated. The wide range of BMP options can be organized into several classifications by determining what each BMP can accomplish. Many are designed to control ero- sion and contain sediment transport. These are particularly important in the active construction phase where site stabiliza- tion has not yet occurred. Some BMPs can and should be in- stalled before construction. Sediment containment devices, such as silt fences, continuous berms, and turbidity barriers, often are mandated and installed before construction com- mences. Other BMPs deal with. controlling the quantity of runoff that will occur as a result of construction activities and postconstruction changes in flow that will result from in- creased imperviousness on the completed site. Finally, many different types of BMPs focus on water quality by treating the runoff to reduce other pollutants that are generated during the construction and postconstruction phases. Another consideration is how maintenance will be per- formed over the long run. Planners need to think of BMP se- lection as a revolving process of installation, inspection, main- tenance, and enforcement (I2ME). Although this article focus- es on the selection aspects, decision- makers need to consider I2ME to ensure long -term performance of BMPs. Many tech- niques and technologies involve lower up -front costs, but in- stallation and maintenance costs over time must be factored into the equation. Many quality and quantity issues can be resolved through efficient site designs that incorporate practices that prevent the transport of water and pollutants from increasing as a re- sult of development. These preventive measures can greatly reduce the need for reactive designs and technologies that are needed to contain water and remove pollutants of concern. This article focuses on the organization and classification of structural BMPs and related stormwater treatment devices (SWTDs), which are structural or nonstructural BMPs that positively impact stormwater quality before, during, or after construction or construction - related land - disturbing activities. SWTDs might be temporary or permanent, depending on their desired application or function. SWTDs might be "proac- tive" or "reactive" in their approach or application. Examples of proactive SWTDs include erosion control practices, green roofs, vegetative filter strips, and rain barrels. Reactive tech- niques might employ sediment control practices, inline treat- ment devices, sedimentation ponds, and detention /retention systems. Active Construction Sediment Containment Systems The role of sediment control systems is to create conditions for sedimentation, allowing soil particles that are held in sus- pension to settle. When soil - particle transport mechanisms flow at slow rates, particles can settle out of suspension. How deposition occurs depends on several parameters. Sediment control systems generally are hydraulic controls that function by modifying the storm - runoff hydrograph and slowing water velocities, allowing for the deposition of sus- pended particles by gravity. Some of the more common r1�t((rfr�0,1\f J__ X RUNOFUl- JIIJ Passively treat all stormwater runoff cost - effectively -Complies with NPDES, 40 CFR 122.26 (1999) when used as Best Management Practice in storm water pollution prevention plans Captures hydrocarbons (TPH), total suspended solids (TSS), particulate heavy metals The Inceptor requires only biannual PolyDak filter replacement Retrofitted to any catch basin or curb inlet opening PolyDak filter captures particles greater than .044mm. Extremely hydrophobic allowing for high flow rates to be treated No excavation or alterations necessary PolyDak filter is non - hazardous solid waste Stainless steel unit construction lasts a lifetime Peaked -top design sheds debris Open -top design captures debris AML 11 uuLU 11Uf% 5, INC. stormdrains.com - 687 -7473 nment, One Storm Drain at a Time Circle #71 on Reader Service Card on S O L U T I O N S names for these structures are sediment basins, sediment ponds, and sediment traps. When designed correctly, sedi- ment containment systems should provide sufficient contain- ment storage volume to handle incoming waters, create uni- form flow zones within the containment storage volume for the deposition of suspended particles, and discharge water at a controlled rate. When all runoff waters are captured, the efficiency of the containment system is nearly 100%. Retaining all runoff wa- ters from a construction site usually is impossible, however, because large containment areas and volumes are required. In addition, evaporation and infiltration might not be sufficient to drain the system before the next storm event occurs, which might cause flooding problems. Finally, retained waters might hamper maintenance of the system because removing cap- tured sediments becomes more complicated with the presence of water. Because of these concerns, rather than attempting to re- tain all runoff waters, a containment system should provide sufficient volume for capturing suspended particles while al- lowing discharge to occur. This provides the advantage of de- taining incoming runoff to control the discharge of suspended particles while not requiring large areas to store runoff wa- ters. Flooding problems from sequential storm events are re- duced because contained waters usually will be drained from the system between events. Finally, frequent maintenance is facilitated because the sediments do not remain saturated with water. If detaining runoff from construction sites is to be effective in removing suspended particles, contained waters must re- 7i�_ BAY AVER main long enough for the deposition of suspended particles within the system. Because outflow from the system will oc- cur, 100% reduction of all incoming suspended particles will not be possible. However, high efficiencies can occur for sedi- ment containment systems developed for design -size particles and are described in detail by Jerald S. Fifield in Designing for Effective Sediment and Erosion Control on Construction Sites (2001) and Field Manual on Sediment and Erosion Control Best Management Practices for Contractors and Inspectors (2002). Documentation on the effectiveness of containment sys- tems for trapping suspended solids is limited, and there are conflicting opinions on their actual effectiveness. If properly designed, constructed, inspected, and maintained, however, containment systems are effective in trapping sediment. This discussion focuses on selected manmade, nonstructur- al sediment - containment systems that act as barriers or filters. A barrier is any structure that obstructs or prevents the pas- sage of water. If runoff cannot pass through a barrier, then water will either be contained or flow over the structure. Commonly used manmade barrier devices include silt fences, continuous geotextile- wrapped berms, wattles, turbidity bar-n- ers, and geosynthetic silt dikes. Because their effectiveness is minimal for large runoff events, these devices must be careful- ly installed, and their usefulness generally is limited to low - volume flows from smaller storm events. As such, these sys- tems are typically only used and installed during the precon- struction and active- construction phases of a project. Appropriate places to use sediment control barriers include: • along sections of a site perimeter, • below disturbed areas subject to sheet and rill erosion, BaySavers cost effectively meets local and national stormwater requirements • Municipal, Commerical, Highway, Residential Projects . Customizable to your site conditions • Use under impervious areas, great as retrofits • Listed in the National BMP Database • Minimal head loss, large treatment flow range For Details Call 1- 800 - 229 -7283 BaySaver Stormwater Treatment Systems Your Best Value Per Treated CFS'" www.BaySaver.com Circle #36 on Reader Service Ccad '�'T • below the toe of exposed and erodi- ble slopes, • along the toe of stream and channel banks, • low -flow swales and ditches, • around area drains or inlets located in a sump. Turbidity barriers are used in low -flow streams, tidal areas, or lakes. Inappropriate places to use sediment control barriers include: • parallel to a contour when installed on a hillside; • in channels where concentrated flows occur, unless properly reinforced; • upstream or downstream of culverts where concentrated flows occur; • in front of or around inlets where concentrated flows occur and sump conditions do not exist; • in continuously flowing streams or ephemeral channels. Filtration Devices Other SWTDs used during active con- struction are designed to provide sedi- ment containment and /or filtration. These might include geotextile catch basin inserts, geosynthetic drainage and curb inlet filters, geotextile tubes, and geotextile filter bags. These materials al- low water to flow through them while filtering or capturing sediment. Selecting the correct geotextile or fiber consisten- cy will reduce the possibility of blinding or clogging the device with excessive sediment. Appropriate places to use geosyn- thetic filters include in front of or around gutters and drain inlets where sump conditions exist and in areas of dewatering of detention /retention ponds or dredging of construction and /or in- dustrial spoils. Inappropriate places to use geosyn- thetic filters include in front of or around inlets where concentrated flows occur and sump conditions do not exist, in channels where concentrated flows occur, and in continuously flowing streams or ephemeral channels. Manmade geosynthetic SWTDs and filters have numerous advantages over traditional sediment control practices derived from natural materials. They usually are easier to transport, install, and maintain as compared to straw and hay bales or soil and rock structures. Manufacturing and fabrication consis- tencies enable the performance of geosynthetic devices to be more pre- dictable and generally superior to that of natural materials. In some cases these devices may be washed and reused. Postconstruction Postconstruction structural BMPs are techniques that can be used to address flow quantity control of and treatment for water quality through pollutant re- moval in wet - weather runoff. These BMPs can include site - specific engi- neered designs as well as proprietary systems. The challenge with any attempt to organize or classify BMPs by type or function is that many fit into multiple categories. In the interest of clarity, however, structural BMPs can be grouped into several classifications by function, including the following: • Infiltration systems • Detention systems • Retention systems • Vegetated systems • Filtration systems • Hydrodynamic separation systems These structural BMPs can be fur- ther organized into three primary types: vegetative techniques and open -space designs, designed structures, and manu- factured technologies. Table 1 shows a proposed classification of BMPs based Circle #50 on Reader Service Card 84 StormwOter • July /August 2003 www.stormh2o.com Table 2. Basic Functions of Stormwater Treatment Devices Sediment Containment is Silt Fences • Continuous Berms • Wattles is Drain Inlet Barriers • Channel Silt Dikes • Turbidity Barriers • Geotextile Fitter Bags • Geotextile Tubes Filtration is Catch Basin Inserts Type I — Geotextile Filtration Systems Type II — Multichamber Permanent Structures • Curb Inlet Filters Type I — Exterior - Geotextile Filtration Systems Type II — Interior - Multichamber Permanent Filtration Systems Separation • Hydrodynamic Separation Devices lnfi&adon • infiltration Chamber Systems Detention • Underground Piping Systems 0 Your guarantee that you're buying genuine Earth .Saver° Wattles. The Industry's Only Patented, Scientifically Tested Wattle Earth Saver Wattles (pre - manufactured fiber rolls) have been rigorously tested' and have performance specifications to substantiate product quality. • Proven waterqualityenhancement y' through measurable sediment reduction VIM, 4% • Certified, 100% weed -free . • Best management practice (BMF') — used =tea by CaITRANS, FHWA, USFS, USDA, and local municipalities • Meets federal and state OSHA safety standards '4,►A S,0 `� Insist that your distributor provide you with Q� `f genuine Earth Saver Wattles. 4+. !V www.earth- savers.com 1 -866- WATTLES • 1- 866- 928 -8537 s'on�ontro�Q��ao Quality & Service You Expect • Made in USA • Available Nationwide Reduce Slope Length • Capture Inlet Sediment Prevent Construction Sedimentation • Promote Revegetation • San Diego State university, Soil Erosion Research Laboratory Circle #54 on Ruder Service Card Table 1. Classification of Structural BMPs Ve etadve Rechniques and Open-Space Designs • Constructed Wetlands • Bioretention Systems • Swales is Filter Strips to Rain Gardens is Green Roofs Designed Structures • Porous Pavement • Below- Surface Chamber Systems • Infiltration Basins/Trenches • Dry Wells • Detention Basins • Oversized Pipes • Retention Ponds (Wet Ponds) • Design -Sand Fitters Manufactured or Propfietary Proprietary Technologies • Hydrodynamic Separator Systems • Filtration Systems Inline Filtration Systems Catch Basin Inserts — Long Term /Short Term Exterior Treatments • Stormwater Underground Storage Tanks • Fabricated Underground Piping Systems • Sediment Containment Devices drain your WATER not your budget:: • GREATER INFLOW AREA THAN PIPE • HIGHER FLOW CAPACITY THAN PIPE • NO CLOGGING - EASY TO INSTALL • PROTECTS WATERPROOFING • HALF THE COST OF STONE & PIPE AWD pnifaGncated drains are manufactured from a formed plastic core covered on one or both sides with a geotext* fitter fabric. The fabric allows liquids or gases to tte efficiently collected into the drain core and transported out through designated drainage exits. OOOO tai BETTER �. BEST 6— 6. s. Dian Zit TMI Orzn 1 Dn fW slits Oran 1 mt.1—xii, N s-, Orain Pip• 6 Scone /ii+iKWAi RAIIV 9aiPRein �'• AIM ER ©RA1Ni5h eet U—in I OTALLIIiiiiiiRAINa "sheet oral" 0 AmauCANWcKli commRAT1ory alDY AM!•rt ea•/ IYaww.N[ !•1a0, ue. oe a•aFwara��o•a�e -ezaa s.: �o. auc -Deco ..w..r.,..lv..wla.sa.. a.roe.a.a..w....axr..x•.a Circle #81 on Reader Service Card 86 Stormwater • July//August 2003 1 www.stormh2o.com on type and function and provides exam- ples of each type. Remember that many BN1Ps serve multiple functions. For a broad overview of the types and functions of structural and nonstructural BMP types, see "Preparing for the Storm: BMP Selection for Phase II Compliance" (Stormwater Buyers Guide 2002, www.forester. net /sw 0105_preporinq.htlnl� ). A clear under- standing of the postconstruction BMP options will help clarify the assessment and selection process for meeting active construction and postconstruction re- quirements. The balance of this article presents a proposed matrix system for selecting appropriate manufactured stormwater treatment devices for specif- ic site application needs during all phas- es of the construction process. Functions of Manufactured SWTDs Basic functions of manufactured SWTDs can be grouped into five major cate- gories. These are sediment containment, filtration, separation, infiltration, and un- derground detention. Although it is be- yond the scope of this article to describe and classify all the types of BMPs that might be used to fulfill these functions, various manufactured SWTDs may be grouped by primary function, as shown in Table 2. Once the function required of an SWTD has been determined, it is time to consider when and where it should be employed. Failure to properly install an SWTD in the correct location or se- quence of a land - disturbing activity might result in failure or compromised performance. After the appropriate application or function of the required stormwater treatments has been determined, these parameters may be coupled to facilitate selection of the most appropriate SWTD. "fable 3 presents a matrix that combines function with construction phases for identifying potential SWTDs for selec- tion consideration. Finally, where to use an SWTD must be considered. Although it is beyond the scope of this article to present specific site locations for the vast potential vari- ances of SWTD applications, Table 4 presents a matrix coupling site location with the various construction phases. Combining Tables 3 and 4 might help end users make informed decisions when considering SWTDs for various functions, construction phases, and site locations. Phase II- Stormwater Treatment Solved! tr � l l l r QQ One company providing full range of innovative 'CSh'`j'd ® treatment products for stormwater compliance. • Independent university performance evaluations show 91% TSS annualized removal • Proven pretreatment for stormwater storage structures Aqua- FilterTM Treatment System • Filters greater than 80% of fine sediment,TPH, Phosphorus, and certain metals • Captures floatable oil, debris and sediment in urban stormwater runoff Aqua- SwirITM Concentrator • Engineered for your site's needs and Contractor recommended for new & retrofit installations • Strong, durable, lightweight and leak proof HDPE construction perASTM standards • Each product has a patented modular design and arrives on the job site assembled for installation Use our Project Design Assistant (PDA) at www.aquashieldinc.com for proper specifying, AutoCAD drawings for quick permitting, and communication with local sales representatives. Corporate Office (888) 344 -9044 Circle #57 on Reader Service Card Aqua- Guard"m Catchbasin Insert ETV EPA's Environmental Technology Venfication Program Avoid Fines!° Get compliant with the surprisingly �® affordable, closed -loop wash rack from Riveer. 888.857.7304 www.cyclonator.com sales @riveer.com Circle #38 on Reader Service Card www.siormh2o.com I July /August 2003 - StorMWCLter 87 Table 3. Function and Typical Construction Phase(s) for Applying Manufactured Stormwater Treatment Devices Function Construction Phase Preconstruction Active Construction Postconstruction Sediment Containment Silt Fences Silt Fences Catch Basin Inserts — Type II Continuous Berms Continuous Berms Curb Inlet Filters — Type II Turbidity Barriers Turbidity Barriers Hydrodynamic Separation Devices Catch Basin Inserts — Types I and Il Drain Inlet Barriers Curb Inlet Filters —Types I and II Channel Silt Dikes Geotextile Filter Bags Geotextile Tubes Filtration Catch Basin Inserts — Type II Catch Basin Inserts — Type II Curb Inlet Filters — Type II Curb Inlet Filters — Type II Geotextile Filter Bags Geotextile Filter Bags Geotextile Tubes Geotextile Tubes Hydrodynamic Separation Devices Separation Hydrodynamic Separation Devices Infiltration Infiltration Chamber Systems Detention Underground Piping Systems Best Management Products, Inc Affordable (Phase 2 Stormwater Options Reduce Trash, Floatables, Oil and Grit BMP Solutions for the Real World Ah (800) 504 8008 www.binpinc.com U.S. PATENT #6,126,817 - Circle #46 on Reader Service Crud CULTEC, Inc. Quality Stormwater & Wastewater Management Systems RECHARGER TM • CONTACTOR HVLV TM STORMFILTERTM CULTEC, Inc. 1- 800 -4- CULTEC P.O. Box 280 www.cultec.com 878 Federal Road Brookfield, CT 06804 custservice @cultec.com U.S. Patent No 5,087 151 U.S. Patent No 5,419.838. U.S. Patent No, 6.322.286 81. Other U.S. and Foreign patents. Other U.S. patents pending. RECHARGER ". CONTACTOR', STORMFILTER'° 8 HVLV"' are trade names of CULTEC, Inc. © 2003 CULTEC, Inc. All rights reserved. Circle #76 on Reader Service Ccud 88 StoIInwateI • July /August 2003 1 www.stormh2o.com Table 4. Site Location and Typical Phase(s) of Construction for Applying Manufactured Stormwater Treatment Devices Site Location Construction Phase Preconstruction Active Construction Postconstruction Perimeter Silt Fences Silt Fences Continuous Berms Continuous Berms Catch Basin Inlet, Catch Basin Inserts — Types I and II Catch Basin Inserts —Type II Curb Inlet Drain Inlet Barriers Curb Inlet Filters — Type II Curb Inlet Filters —Types I and II Hydrodynamic Separation Devices Hydrodynamic Separation Devices Channel Channel Silt Dikes Slopes Silt Fences Silt Fences Continuous Berms Continuous Berms Wattles Wattles Waterway Turbidity Barriers Turbidity Barriers Geotextile Tubes Geotextile Tubes Sediment Basin/Trap Geotextile Fitter Bags Geotextile Filter Bags Below Impervious Surfaces Infiltration Chamber Systems Infiltration Chamber Systems Underground Piping Systems Underground Piping Systems Conclusion To ensure that regulators, planners, engineers, and contrac- tors have a clear picture of what techniques and measures can be used in the various construction phases for proper BMP management, a solid understanding of the options is essential. By classifying the various sediment controls and postconstruction BMPs into proper applications, stormwater professionals are far more likely to develop efficient yet cost- effective stormwater plans for specific projects. A thor- ough understanding of the installation, inspection, mainte- ANEW STANDARD IN I SPILL COLLECTION HAS Yk Y' AM i' 111111111•:. +n' The nexv standard,is the Century HDPE Envtropan�. Designed by railroad.people, the HDPE Enviropan� ` t offers the most advanced and innovative technology to l allroad spill call c.tton .; nufacture,d taut bf.`didr high - impact resistent High - Density Polyethylene, the Century Enviorpane can meetyouurspili collection needs. Your Railroad Spill Collfecjioln:Pan;Source HDPE ENWIROPANli Call 1-800-527'5232, Ext. 118 �., e -miff: sales @cennn -ygrp.com or visit u§, at wwwx. ntUrygtp.cotra Circle #77 on Reader Service Ccad www.stormh2o.com nance, and enforcement requirements also will result in a more comprehensive and realistic cost analysis of the pro- ject. The result will be cleaner water and a more satisfied general public. V David Woelkers is president of Hydro Compliance Manage- ment Inc. in Whitmore Lake, MI. Marc S. Theisen, M.S., CPESC, is director of business development with SI Geosolu- tions in Chattanooga, TN. Substantial input for this article was received from Jerald S. Fifield, Ph.D., CPESC. Circle # 101 on Reader Service Card July /August 2003 • Stormwater