As general guidelines for constructing temporary bridges, clearing and excavation of the stream shores and bed should be kept to a minimum. Sufficient clearance should be provided for floating objects to pass under the bridge. Abutments should be parallel to the stream and on stable banks. If the stream is less than 8 feet wide at the point where a crossing is needed, no additional in stream supports should be used. If the crossing is to extend across a channel wider than 8 feet (as measured from top of bank to top of bank), the bridge should be designed with one in water support for each 8 feet of stream width.

A temporary bridge should be anchored by steel cable or chain on one side only to a stable structure on shore. Examples of anchoring structures include trees with a large diameter, large boulders, and steel anchors. By anchoring the bridge on one side only, there is a decreased risk of causing a downstream blockage or flow diversion if a bridge is washed out.

When constructing a culvert, filter cloth should be used to cover the streambed and streambanks to reduce settlement and improve the stability of the culvert structure. The filter cloth should extend a minimum of 6 inches and a maximum of 1 foot beyond the end of the culvert and bedding material. The culvert piping should not exceed 40 feet in length and should be of sufficient diameter to allow for complete passage of flow during peak flow periods. The culvert pipes should be covered with a minimum of 1 foot of aggregate. If multiple culverts are used, at least 1 foot of aggregate should separate the pipes.

Fords should be constructed of stabilizing material such as large rocks. Development Document for Construction and Development Proposed Effluent Guidelines June 2002 5 102 Effectiveness Both temporary bridges and culverts provide an adequate path for construction traffic crossing a stream or watercourse.

Limitations Bridges can be considered the greatest safety hazard of all temporary stream crossing structures if not properly designed and constructed. Bridges might also prove to be more costly in terms of repair costs and lost construction time if they wash out or collapse (Smolen et al., 1988).

The construction and removal of culverts are usually very disturbing to the surrounding area, and erosion and downstream movement of soils are often great. Culverts can also create obstructions to flow in a stream and inhibit fish migration. Depending on their size, culverts can be blocked by large debris in a stream and are therefore vulnerable to frequent blockage and washout.

If given a choice between building a bridge or a culvert as a temporary stream crossing, a bridge is preferred because of the relative minimal disturbance to streambanks and the opportunity for unimpeded flow through the channel. The approaches to fords often have high erosion potential. In addition, excavation of the streambed and approach to lay riprap or other stabilization material causes major stream disturbance. Mud and other debris are transported directly into the stream unless the crossing is used only during periods of low flow.

Maintenance Temporary stream crossings should be inspected at least once a week and after all significant rainfall events. If any structural damage is reported to a bridge or culvert, construction traffic should stop using the structure until appropriate repairs are made. Evidence of streambank erosion should be repaired immediately.

Fords should be inspected closely after major storm events to ensure that stabilization materials remain in place. If the material has moved downstream during periods of peak flow, the lost material should be replaced immediately.

Cost In general, temporary bridges are more expensive to design and construct than culverts. Bridges are also associated with higher maintenance and repair costs should they fail. Additional costs may accrue to the site team in terms of lost construction time if a temporary structure is washed out or otherwise fails.

Temporary bridging costs range as a function of the width of the bridge span and the duration of application. If the bridging is permanent, a mean cost of $50 per square foot for an 8 foot wide Development Document for Construction and Development Proposed Effluent Guidelines June 2002 5 103 steel arch bridge (no foundation costs included) can be used for conceptual cost estimation (R. S. Means, 2000). If rental bridging is employed, then rates are probably on the order of 20 to 50 percent of the bridge (permanent) cost, but will range based on the rental duration and mobilization distance.

<IP_ADDRESS>.8 DUST CONTROL General Description Dust control measures are practices that help reduce ground surface and air movement of dust from disturbed soil surfaces. Construction sites are good candidates for dust control measures because land disturbance from clearing and excavation generates a large amount of soil disturbance and open space for wind to pick up dust particles. To illustrate this point, research at construction sites has established an average dust emission rate of 1.2 tons/ acre/ month for active construction (WA Dept. of Ecology, 1992). These airborne particles pose a dual threat to the environment and human health. First, dust can be carried off site, thereby increasing soil loss from the construction area and increasing the likelihood of sedimentation and water pollution. Second, blowing dust particles can contribute to respiratory health problems and create an inhospitable working environment.

Applicability Dust control measures are applicable to any construction site where dust is created and there is the potential for air and water pollution from dust traveling across the landscape or through the air. Dust control measures are particularly important in arid or semiarid regions where soil can become extremely dry and vulnerable to transport by high winds.

Also, dust control measures should be implemented on all construction sites where there will be major soil disturbances or heavy construction activity, such as clearing, excavation, demolition, or excessive vehicle traffic. Earthmoving activities are the major source of dust from construction sites, but traffic and general disturbances can also be major contributors (WA Dept. of Ecology, 1992).

The specific dust control measures implemented at a site will depend on the topography, land cover, soil characteristics and amount of rainfall at the site.

Design and Installation Criteria When designing a dust control plan for a site, the amount of soil exposed will dictate the quantity of dust generation and transport. Therefore, construction sequencing and disturbing small areas at one time can greatly reduce problematic dust from a site. If land must be disturbed, additional temporary stabilization measures should be considered prior to disturbance. Development Document for Construction and Development Proposed Effluent Guidelines June 2002 5 104 A number of methods can be used to control dust from a site. The following is a brief list of control measures and their design criteria. Not all control measures will be applicable to a given site. The owner, operator, and contractors responsible for dust control at a site should determine which practices accommodate their needs based on specific site and weather conditions.

Sprinkling/ Irrigation: Sprinkling the ground surface with water until it is moist is an effective dust control method for haul roads and other traffic routes (Smolen et al., 1988). This practice can be applied to almost any site.

Vegetative Cover: In areas not expected to handle vehicle traffic, vegetative stabilization of disturbed soil is often desirable. Vegetative cover provides protection to surface soils and slows wind velocity at the ground surface, thus reducing the potential for dust to become airborne.

Mulch: Mulching can be a quick and effective means of dust control for a recently disturbed area (Smolen et al., 1988).

Wind Breaks: Wind breaks are barriers (either natural or constructed) that reduce wind velocity through a site and therefore reduce the possibility of picking up suspended particles. Wind breaks can be trees or shrubs left in place during site clearing or constructed barriers such as a wind fence, snow fence, tarp curtain, hay bale, crate wall, or sediment wall (USEPA, 1992).

Tillage: Deep tillage in large open areas brings soil clods to the surface where they rest on top of dust, preventing it from becoming airborne.

Stone: Stone can be an effective dust deterrent for construction roads and entrances.

Spray on Chemical Soil Treatments (palliatives): Examples of chemical adhesives include anionic asphalt emulsion, latex emulsion, resin water emulsions, and calcium chloride. Chemical palliatives should be used only on mineral soils. When considering chemical application to suppress dust, consideration should be taken as to whether the chemical is biodegradable or water soluble and what effect its application could have on the surrounding environment, including waterbodies and wildlife. Development Document for Construction and Development Proposed Effluent Guidelines June 2002 5 105 Table 5 23 shows application rates for some common spray on adhesives as recommended by Smolen et al. (1988).

Table 5 23. Application Rates for Spray On Adhesives Spray on Adhesive Water Dilution Type of Nozzle Application (gal/ acre)

Anionic Asphalt Emulsion 7: 1 Coarse spray 1,200 Latex Emulsion 12.5: 1 Fine spray 235 Resin in Water 4: 1 Fine spray 300 Source: Smolen et al., 1988.

Effectiveness Sprinkling/ Irrigation: Not available.

Vegetative Cover: Not available.

Mulch: Can reduce wind erosion by 80 percent.

Wind Breaks/ Barriers: For each foot of vertical height, an 8 to 10 foot deposition zone develops on the leeward side of the barrier. The barrier density and spacing will change its effectiveness at capturing windborne sediment.

Tillage: Roughening the soil can reduce soil losses by approximately 80 percent.

Stone: The sizes of the stone can affect the amount of erosion that will take place. In areas of high wind, small stones are not as effective as a 20 cm stone.

Spray on Chemical Soil Treatments (palliatives): Effectiveness of polymer stabilization methods ranges from 70 percent to 90 percent.

Limitations In areas where evaporation rates are high, water application to exposed soils may require near constant attention. If water is applied in excess, runoff may result from the site and possibly create conditions where vehicles could track mud onto public roads.

Chemical applications should be used sparingly and only on mineral soils (not high organic content soils) because their misuse can create additional surface water pollution from runoff or contaminate groundwater. Chemical applications might also present a health risk if excessive amounts are used. Development Document for Construction and Development Proposed Effluent Guidelines June 2002 5 106 Maintenance Because dust controls are dependent on specific site conditions, including the weather, inspection and maintenance are unique for each site. Generally, however, dust control measures involving application of either water or chemicals require more monitoring than structural or vegetative controls to remain effective. If structural controls are used, they should be inspected for deterioration on a regular basis to ensure they are still achieving their intended purpose.

Cost Chemical dust control measures can vary widely in cost depending on specific needs of the site and level of dust control desired. One manufacturer of a chloride product estimated a cost of $1,089 per acre for application to road surfaces, but cautioned that cost estimates without a specific site evaluation are rather inaccurate.

<IP_ADDRESS>.9 STORM DRAIN INLET PROTECTION Description Storm drain inlet protection measures are controls that help prevent soil and debris from on site erosion from entering storm drain drop inlets. Typically, these measures are temporary controls that are implemented prior to large scale disturbance of the surrounding site. These controls are advantageous because their implementation allows storm drains to be used during even the early stages of construction activities. The early use of storm drains during project development significantly reduces the occurrence of future erosion problems (Smolen et al., 1988).

Three temporary control measures to protect storm drain drop inlets are ° Excavation around the perimeter of the drop inlet ° Fabric barriers around inlet entrances ° Block and gravel protection Excavation around a storm drain inlet creates a settling pool to remove sediments. Weep holes protected by gravel are used to drain the shallow pool of water that accumulates around the inlet. A fabric barrier made of porous material erected around an inlet can create an effective shield to sediment while allowing water to flow into the storm drain. This type of barrier can slow runoff velocity while catching soil and other debris at the drain inlet. Block and gravel inlet protection uses standard concrete blocks and gravel to form a barrier to sediments while permitting water runoff through select blocks that are laid sideways. Development Document for Construction and Development Proposed Effluent Guidelines June 2002 5 107 In addition to the materials listed above, limited temporary storm water drop inlet protection can also be achieved with the use of straw bales or sandbags to create barriers to sediment.

For permanent storm drain drop inlet protection after the surrounding area has been stabilized, sod can be installed as a barrier to slow storm water entry to storm drain inlets and capture sediments from erosion. This final inlet protection measure can be used as an aesthetically pleasing way to slow storm water velocity near drop inlet entrances and remove sediments and other pollutants from runoff.

A new technology that uses an insert trap into the inlet itself has been developed (Adams et al., 2000). This technique showed good results on initial tests, trapping more than 50 percent of the incoming sediment in flows typical of those into urban storm drains. This technique is being further developed with a pending patent application.

Applicability All temporary controls should have a drainage area no greater than 1 acre per inlet. It is also important for temporary controls to be constructed prior to disturbance of the surrounding landscape. Excavated drop inlet protection and block and gravel inlet protection are applicable to areas of high flow where overflow is anticipated into the storm drain. Fabric barriers are recommended for smaller, relatively flat drainage areas (slopes less than 5 percent leading to the storm drain).

Temporary drop inlet control measures are often used in combination with each other and with other storm water control techniques.

Design and Installation Considerations Hydrologic Design Hydrologic computations are not necessary with present technologies. A specified limitation of 1 acre per inlet limits flow rates, dependent on local rainfall and runoff considerations.

Installation Criteria and Specifications The following criteria should be followed until future research establishes better techniques:

° With the exception of sod drop inlet protection, these controls should be installed before any soil disturbance in the drainage area.

° Excavation around drop inlets should be dug a minimum of 1 foot deep (2 feet maximum) with a minimum excavated volume of 35 cubic yards per acre disturbed. Side slopes leading to the inlet should be no steeper than 2: 1. The shape of the excavated area should be Development Document for Construction and Development Proposed Effluent Guidelines June 2002 5 108 designed such that the dimensions fit the area from which storm water is anticipated to drain. For example, the longest side of an excavated area should be along the side of the inlet expected to drain the largest area.

° Fabric inlet protection is essentially a filter fence placed around the inlet. The fabric asures should not be used as stand alone sediment control measures. To increase inlet protection effectiveness, these practices should be used in combination with other measures, such as small impoundments or sediment traps (USEPA, 1992). Temporary storm drain inlet protection is not intended for use in drainage areas larger than 1 acre. Generally, storm water inlet protection measures are practical for relatively low sediment and low volume flows.

Frequent maintenance of storm drain controls is necessary to prevent clogging. If sediment and other debris clog the water intake, drop intake control measures can actually cause erosion in unprotected areas.

Maintenance All temporary control measures must be checked after each storm event. To maintain the sediment capacity of the shallow settling pools created from these techniques, accumulated sediment should be removed from the area around the drop inlet (excavated area, around fabric barrier, or around block structure) when the sediment storage is reduced by approximately 50 percent. Additional debris should be removed from the shallow pools on a periodic basis.

Weep holes in excavated areas around inlets can become clogged and prevent water from draining from the shallow pools that form. Should this happen, unclogging the water intake may be difficult and costly.

Cost The cost of implementing storm drain drop inlet protection measures will vary depending on the control measure chosen. Generally, initial installation costs range from $50 to $150 per inlet, with an average cost of $100 (USEPA, 1993). Maintenance costs can be high (annually, up to 100 percent of the initial construction cost) because of frequent inspection and repair needs. The Southeastern Wisconsin Regional Planning Commission has estimated that the cost of installation of inlet protection devices ranges from $106 to $154 per inlet (SEWRPC, 1991).

<IP_ADDRESS>.10 POLYACRYLAMIDE (PAM)

General Description The term polyacrylamide (PAM) is a generic term that refers to a broad class of compounds. There are hundreds of specific PAM formulations, and all have unique properties that depend on polymer chain length and number and kinds of functional group substitutions along the chain. Development Document for Construction and Development Proposed Effluent Guidelines June 2002 5 109 PAMs are classified according to their molecular weight and ionic charge and are available in solid, granular, liquid, or emulsion forms.

PAM's effectiveness to prevent or reduce erosion is due to its affinity for soil particles, largely via coulombic and Van der Waals attraction. These surface attractions enhance particle cohesion, stabilizing soil structure against shear induced detachment and transport in runoff. In a soil application, PAM aggregates soil particles, increasing pore space and infiltration capacity, resulting in reduced runoff. These larger particle aggregates are less susceptible to raindrop and scour erosion, thus reducing the potential to mobilize sediments.

Applicability Because of ease in application, PAM is well suited as a short term erosion prevention BMP, especially for areas with limited access or steep slopes that hinder personnel from applying other cover materials. PAM can be used to augment other cover practice BMPs, though it can be effective when applied alone. Thus, the ease of application, low maintenance, and relatively low cost associated with PAM make it a practical solution to soil stabilization during construction.

Application Criteria PAM can be applied to soil through either a dry granular powder or a liquid spray form. Optimal application rates to prevent erosion on construction sites are generally less than 1 kg/ ha (about 1 lb/ ac) (Tobiason et al., 2000). However, the concentration required can vary for specific soil properties and construction phases. WDOT (2002) suggests a dosage of 60 mg/ L for roadway erosion and sediment control. This is higher than the rate recommended by the University of Nebraska for an agricultural application (10 parts per million). To put this into context, one half pound of PAM in1000 gallons of water results in a PAM concentration of 60 mg/ L, which treats 1 acre of exposed soil to WDOT recommendations.

Effectiveness A study performed in Dane County, Wisconsin, analyzed 15 small plots (1 meter x 1 meter) for runoff and sediment yield on a construction site. The study concluded that when a solution of PAM mix with mulch/ seeding was applied to dry soil and compared with the control (no PAMmix application to dry soil), an average reduction of 93 percent in sediment yield was found. An average reduction of 77 percent in sediment yield was the worst performing PAM treatment and occurred when PAM mix in solution was applied to moist soil. The application of dry PAM mix to dry soil reduced sediment by 83 percent and decreased runoff by 16 percent when compared to the control. The results show that regardless of the application method, PAM mix was effective in reducing sediment yield in the test plots (Roa Espinosa et al., 2000). Development Document for Construction and Development Proposed Effluent Guidelines June 2002 5 110 A second study performed in Washington analyzed the runoff from three different construction sites: an erosion control test facility, a highway construction site, and an airport runway. Table 5 24 summarizes the 225 samples analyzed in Tobiason et al. (2000).

Table 5 24. Turbidity Reduction Values from PAM Volume, m 3 Turbidity Reduction (%) Maximum 350 99.97 Median 285 97.6 Minimum 133 46 Limitations Currently PAMs are most commonly produced as dry granules. They completely dissolve and remain dissolved if mixed properly. If added too quickly or if not stirred vigorously the granules rapidly form nondissolvable gels on contact with water or collect in low turbulence areas as syrupy concentrations that dissolve slowly in an uncontrolled pattern over a period of hours or days (USDA, 1994).

In addition, when spilled on hard surfaces, PAM solutions are extremely slippery and hazardous to foot and vehicle traffic. PAM dust is highly hygroscopic and, if inhaled, could impair breathing. Certain neutral and cationic PAMs at very high exposure levels produce irritation in humans and are somewhat toxic to certain aquatic organisms; therefore, PAM should be used in strict compliance with state and federal label requirements.

Finally, although PAM is rather inexpensive, there are considerable infrastructure needs and operating costs; thus, sophisticated onsite polymer treatment systems may not be appropriate for certain projects.

Cost The cost of PAM ranges from $1.25 per pound to $5.00 per pound (Entry et al., 1999). The cost of PAM application depends on the system employed. PAM can be used in a centralized treatment system (e. g., at a sedimentation basin) to treat larger areas, or dispersed in granular or liquid form. In Tobiason et al. (2000), the startup costs for the batch treatment system amounted to $90,000. Monthly expenses averaged $18,000 for operations and maintenance and $13,000 for materials and equipment. The total costs for this phase totaled about $245,000, less than 1 percent of total construction costs. If dispersed through irrigation systems (for agriculture), the seasonal cost of PAM treatment is $9 to $15 per acre (Kay Shoemake, et. al., 2000), where a season probably requires between 5 and 10 applications.

For construction sites, it is more likely that PAM would be applied as an additive to the hydroseed mix and applied when final grade is established and cover vegetation is installed. Development Document for Construction and Development Proposed Effluent Guidelines June 2002 5 111 Based on a recent scan of the Internet, there are numerous suppliers who provide PAM as a low cost additive for hydroseeding, suggesting PAM application costs can be incorporated into that of hydroseeding ($ 540 to $700 per acre depending on which seed is applied). An additional cost would be incurred to sample site soils to customize the dosage and delivery mechanisms for individual sites. In addition, re application of PAM in granular or liquid form to areas with rill development (poor vegetation cover) would require additional funds. Where re application of granular PAM is used, R. S. Means (2000) suggests a cost of approximately $5 per 1000 square feet for spreading soil admixtures by hand. Development Document for Construction and Development Proposed Effluent Guidelines June 2002 5 112 5.1.6 SUMMARY The BMP information presented in sub section 5.1 is summarized in Tables 5 25 through 5 28.

Table 5 25. Summary of Information on Erosion Control and Prevention BMPs (Sub section <IP_ADDRESS>) BMP Type Physical Impact Mitigation Other Impacts Receiving Water Quality Downstream Impacts Planning/ Staging/ Scheduling Could be low cost. One data set shows 42% reduction in sediment yield due to planning/ staging/ scheduling. Requires additional advance planning and management. Impact could be evaluated with models as well as experimentally since several computer models are available. Could be low cost. Database is poor. No validated urban runoff models available for theoretical analysis of downstream impacts. Potential exists to modify existing models to make the analysis of downstream impacts on geomorphology. No good cause effect relationships available. Other impacts not evaluated.

Vegetative Stabilization Could be low cost Can be very effective in some cases with advance planning. Can be important on streambanks. Limited applicability in the active construction area. Complements other practices. Practice is seasonably dependent in most of nation. Impact could be evaluated with models as well as experimentally since several computer models are available. Could be low cost. Database is poor. No validated urban runoff models available for theoretical analysis of downstream impacts. Potential exists to modify existing models to make the analysis of downstream impacts on geomorphology. No good cause effect relationships available. Other impacts not evaluated.

Grass Lined Channels Long history of use in channels draining disturbed areas. Well established procedures for design and extensive database on stable designs under widely varied conditions. Some procedures are available, with limited validation, to obtain a first estimate of sediment trapping by grasslined channels. Limited database on trapping of sediment. Database is poor. No validated urban runoff models available for theoretical analysis of downstream impacts. Some potential exists to modify existing models to make the analysis of downstream impacts on geomorphology. No good cause effect relationships available. Database shows wide variations in effectiveness in trapping chemicals. Other impacts not evaluated. Development Document for Construction and Development Proposed Effluent Guidelines Table 5 25. Summary of Information on Erosion Control and Prevention BMPs (Sub section <IP_ADDRESS>) BMP Type Physical Impact Mitigation Other Impacts Receiving Water Quality Downstream Impacts June 2002 5 113 Seeding Low cost method for establishing vegetation. Occurs near the end of active construction. Requires significant time for establishment. Need a prepared seedbed. Good database on impact on soil erosion. Should be supported by other BMPs. Should not be evaluated as standalone practice, but as part of a system. Database is poor. No validated urban runoff models available for theoretical analysis of downstream impacts. Some potential exists to modify existing models to make the analysis of downstream impacts on geomorphology. No good cause effect relationships available. Other impacts not evaluated.

Sodding High cost method of establishing vegetation. Immediate stabilization. Requires significant management attention during establishment. Good database on impact on soil erosion. Very effective way of controlling erosion. Works well for grass waterways and other significant problems area. Should be supported by other BMPs. Should not be evaluated as standalone practice, but as part of a system. Database is poor. No validated urban runoff models available for theoretical analysis of downstream impacts. Some potential exists to modify existing models to make the analysis of downstream impacts on geomorphology. No good cause effect relationships available. Other impacts not evaluated.

Mulching Relatively low cost method of providing cover. Can be highly effective in reducing soil loss when properly anchored. Good database on impact on soil erosion. Variety of materials can be used. Installation is rapid. Not a stand alone practice. Due to interference with construction operations, the times that it can be used during active construction are limited. Database is poor. No validated urban runoff models available for theoretical analysis of downstream impacts. Some potential exists to modify existing models to make the analysis of downstream impacts on geomorphology. No good cause effect relationships available. Other impacts not evaluated. Development Document for Construction and Development Proposed Effluent Guidelines Table 5 25. Summary of Information on Erosion Control and Prevention BMPs (Sub section <IP_ADDRESS>) BMP Type Physical Impact Mitigation Other Impacts Receiving Water Quality Downstream Impacts June 2002 5 114 Erosion Control Matting /Geotextiles Cost is highly variable. Effectiveness in controlling sediment is variable depending on type material. Can provide immediate protection to exposed soils. Not a stand alone practice. Due to interference with construction operations, the times that it can be used during active construction are limited. Disposal is a significant problem and may require landfilling. Can be used for channel linings as stand alone or under riprap. Fair database on effectiveness in preventing erosion. Database is poor. No validated urban runoff models available for theoretical analysis of downstream impacts. Some potential exists to modify existing models to make the analysis of downstream impacts on geomorphology No good cause effect relationships available. Other impacts not evaluated.

Vegetative Buffer Strips Can be highly effective in trapping sediment. Effectiveness is well established and considerable data collected. Well validated models are available to predict the impacts of constructed filter strips on sediment trapping. Models are included in watershed stormwater and sediment models. Modifications needed for natural riparian zones. Require routine maintenance. May be most appropriate where sediment loads are relatively low. Database is poor. No validated urban runoff models available for theoretical analysis of downstream impacts. Some potential exists to modify existing models to make the analysis of downstream impacts on geomorphology No good cause effect relationships available. Other impacts not evaluated. Development Document for Construction and Development Proposed Effluent Guidelines Table 5 25. Summary of Information on Erosion Control and Prevention BMPs (Sub section <IP_ADDRESS>) BMP Type Physical Impact Mitigation Other Impacts Receiving Water Quality Downstream Impacts June 2002 5 115 Topsoiling Important in vegetative establishment. No protection until cover is established. Not a stand alone practice, but must be supported by other BMPs. No known information to describe effectiveness and cost not currently available. Database is poor. No validated urban runoff models available for theoretical analysis of downstream impacts. Some potential exists to modify existing models to make the analysis of downstream impacts on geomorphology No good cause effect relationships available. Other impacts not evaluated. Development Document for Construction and Development Proposed Effluent Guidelines June 2002 5 116 Table 5 26. Summary of Information on Erosion Control and Prevention BMPs (Sub section <IP_ADDRESS>)

BMP Type Physical Impact Mitigation Other Impacts Receiving Water Quality Downstream Impacts Earth Dike ° Used to protect down slope areas. ° Should be stabilized prior to use. ° Requires maintenance after every major storm. ° Can be significant source of sediment if not properly constructed. ° Little data available on its effectiveness as a BMP. ° Can be relatively inexpensive, depending on design. ° Not a stand alone procedure. No known information available. No known information available.

Temporary Swale ° Effectively a grass lined drainage ditch with shallow side slopes. ° Can be applied in many areas, but use limited in arid areas. ° Contaminants that will harm vegetation, such as oils and greases, cannot be discharged to the system. ° Continuous water flow cannot be tolerated by the grass lining. ° Effectiveness depends on infiltration. Can be a problem of groundwater pollution with high water tables. ° Some studies show that they export bacteria. ° Some studies show high removal efficiency for TSS, fair for nutrients, are variable for metals. ° No general relationships available to predict the impact under widely varied climates and conditions, hence the effectiveness cannot be predicted for a given situation beyond the limited database. No known information available. No known information available. Development Document for Construction and Development Proposed Effluent Guidelines Table 5 26. Summary of Information on Erosion Control and Prevention BMPs (Sub section <IP_ADDRESS>)

BMP Type Physical Impact Mitigation Other Impacts Receiving Water Quality Downstream Impacts June 2002 5 117 Temporary Storm Drain Diversion (Pipe) ° Reroutes existing drainage systems. Primary benefit is to separate drainage water originating from undisturbed and construction and reduce the volume of water to be treated. ° Can be combined with other structures, such as sediment traps, and used for sediment trapping. ° Require little maintenance. ° Requires outlet stabilization. Can be a significant source of sediment without outlet stabilization. ° Can be costly, depending on size, installation, and removal. No known information available. No known information available.

Pipe Slope Drain ° Routes runoff from concentrated flow to stabilized areas. ° Can be very effective in eliminating gully erosion problems, if properly installed and maintained. ° Can be constructed from low cost corrugated PVC, but must be anchored or buried along slope. ° Needs to be checked frequently for sedimentation and other maintenance problems. No known information available. No known information available.

Stone Check Dams ° Reduces velocity of flow and prevents erosion. ° Stabilizes channel slope on steep sections by stairstepping. ° Can trap small percentages of sediment behind dam. ° Used for short periods of time where channel lining is impractical. ° Limited lab studies show high effectiveness, but very limited field studies show low trapping efficiency. ° Must be installed such that overtopping occurs over the rock fill and not around the perimeter. ° Should not be used in continuously flowing streams. ° Relatively expensive, if properly installed. ° Procedures for predicting impact of properly installed stone check dams are available and incorporated into watershed computer models. No known information available. No known information available. Development Document for Construction and Development Proposed Effluent Guidelines Table 5 26. Summary of Information on Erosion Control and Prevention BMPs (Sub section <IP_ADDRESS>)

BMP Type Physical Impact Mitigation Other Impacts Receiving Water Quality Downstream Impacts June 2002 5 118 Lined Waterways ° Designed for stability and capacity. ° Local rainfall runoff conditions and linings will influence channel dimensions. ° Require some maintenance during vegetative establishment. ° Not designed as sediment removal device, but to prevent channel erosion. No known information available. No known information available. Development Document for Construction and Development Proposed Effluent Guidelines June 2002 5 119 Table 5 27. Summary of Information on Erosion Control and Prevention BMPs (Sub section <IP_ADDRESS>) BMP Type Physical Impact Mitigation Other Impacts Receiving Water Quality Downstream Impacts Silt Fence Most widely recognized sediment control BMP. Frequently poorly installed with little design consideration. Maintenance is frequently poor, resulting in frequent failure. Frequent maintenance is required for proper operation. Laboratory studies show fair to good sediment trapping by filter fence, but limited field studies do not show the same results. Evaluations of installations show that failure is frequent, coming from undercutting of the fabric and subsequent gully erosion. Should not be installed where rocks and other hard surfaces prevent anchoring. No validated procedures are available to predict the effectiveness of the filter fence in trapping sediment, primarily because of the lack of validated relationships for predicting flow through the filter fence. Procedures for evaluating the anchoring requirements and support post requirements have not adequately accounted for variable soil strength conditions, resulting in frequent failure of the fence under loading. Database is poor. No validated urban runoff models available for theoretical analysis of downstream impacts. Some potential exists to modify existing models to make the analysis of downstream impacts on geomorphology No good cause effect relationships available. Other impacts not evaluated.

Super Silt fence Modification of standard silt fence to improve it structurally. No validation information is available. Recommended to be used where destruction of the silt fence will destroy critical areas. More expensive than standard silt fence. Database is poor. No validated urban runoff models available for theoretical analysis of downstream impacts. Some potential exists to modify existing models to make the analysis of downstream impacts on geomorphology. No good cause effect relationships available. Other impacts not evaluated. Development Document for Construction and Development Proposed Effluent Guidelines Table 5 27. Summary of Information on Erosion Control and Prevention BMPs (Sub section <IP_ADDRESS>) BMP Type Physical Impact Mitigation Other Impacts Receiving Water Quality Downstream Impacts June 2002 5 120 Straw Bale Dike Works by impounding water. Primary trapping mechanism is by settling behind straw bale dike. Information on performance is very limited with much variation in the limited data. Should not be used in waterways or as a perimeter control due to biodegradation. Idealized models of performance are available for systems that are properly installed. Database is poor. No validated urban runoff models available for theoretical analysis of downstream impacts. Some potential exists to modify existing models to make the analysis of downstream impacts on geomorphology No good cause effect relationships available. Other impacts not evaluated.

Sediment Traps Formed by excavation and/ or embankment. Can simplify stormwater control by trapping sediment at specific spots. Can be installed quickly and serve as short term solution to sediment trapping in small areas. May require cleanout. Detailed models as well as simplified design aids are available to predict performance in trapping sediment. Data on performance are available from both laboratory studies and field studies. Will likely control only the settleable solids unless enhanced settling is developed with chemical flocculation. Database is poor. No validated urban runoff models available for theoretical analysis of downstream impacts. Some potential exists to modify existing models to make the analysis of downstream impacts on geomorphology. Data for trapping nutrients are available, but show wide variation. General models of nutrient trapping are not available. Other impacts not evaluated. Development Document for Construction and Development Proposed Effluent Guidelines Table 5 27. Summary of Information on Erosion Control and Prevention BMPs (Sub section <IP_ADDRESS>) BMP Type Physical Impact Mitigation Other Impacts Receiving Water Quality Downstream Impacts June 2002 5 121 Sediment Basins Normally formed by construction of a dam. Stormwater detention basin may serve as sediment basin during construction. Can be used for any size watershed. May require cleanout. Data on performance are available both from laboratory studies and field studies. Will likely control only the settleable solids unless enhanced settling is developed with chemical flocculation. Most reliable and stable structure for obtaining high sediment trapping efficiency under widely varying conditions. Must consider dam safety issues since dam failure is a reasonable possibility. Structures are relatively large and can be expensive. Database is poor. No validated urban runoff models available for theoretical analysis of downstream impacts. Some potential exists to modify existing models to make the analysis of downstream impacts on geomorphology. Data for trapping nutrients are available, but show wide variation. General models of nutrient trapping are not available. Other impacts not evaluated. Development Document for Construction and Development Proposed Effluent Guidelines June 2002 5 122 Table 5 28. Summary of Information on Erosion Control and Prevention BMPs (Sub section <IP_ADDRESS>) BMP Type Physical Impact Mitigation Other Impacts Receiving Water Quality Downstream Impacts Stone Outlet Structures Porous outlet structure constructed of dumped rock, used as the outlet for earth dikes. Requires a stabilized outlet channel until the flow reaches a stable channel. Data on the effectiveness are limited to visual observations of field installations where failure was frequent due to poor installation. Models are available to predict the performance of stone outlets, but field data have not been collected to evaluate the accuracy of the model. No validated urban runoff models available for theoretical analysis of downstream impacts. Some potential exists to modify existing models to make the analysis of downstream impacts on geomorphology. General models of nutrient trapping are not available. Other impacts not evaluated.

Rock Outlet Protection Used to reduce velocity of flow in receiving channel and prevent scouring. Very effective when properly installed. Design procedures are well established. Maintenance is low, if properly installed. Should be inspected after high flows. No data on impact. No data available. No data available.

Sump Pit Used to dewater during excavation. Effectiveness not evaluated. Potential exists to theoretically evaluate the BMP's effectiveness in trapping sediment. Could be used at times other than storm flow, such as removal of groundwater flow. Database is poor. No validated urban runoff models available for theoretical analysis of downstream impacts. Some potential exists to modify existing models to make the analysis of downstream impacts on geomorphology. No data available.

Storm Drain Inlet Protection Used to trap sediment that would otherwise flow into storm drain inlet. Should be installed prior to land disturbance. Effectiveness in removing sediment has not been evaluated, but is thought to be low during construction. Potential exists to use computer models to evaluate effectiveness. Cost can be high for maintenance requirements. Should not be used as stand alone sediment control. Database is poor. No validated urban runoff models available for theoretical analysis of downstream impacts. Some potential exists to modify existing models to make the analysis of downstream impacts on geomorphology. No data available.

Sediment Tank Portable sediment trap. Flows are pumped in and out of the tank. Used where spaced is limited No effectiveness data are available. Expected to be relatively expensive. No data available. No data available. Development Document for Construction and Development Proposed Effluent Guidelines Table 5 28. Summary of Information on Erosion Control and Prevention BMPs (Sub section <IP_ADDRESS>) BMP Type Physical Impact Mitigation Other Impacts Receiving Water Quality Downstream Impacts June 2002 5 123 Stabilized Construction Entrance Used to minimize mud and sediment attached to motorized vehicles. Consists of an area that is covered with rocks over which all vehicles must drive. Can be combined with a wash station. Effective only if all entrances are maintained. Relatively expensive. Will not remove highly cohesive clays. No data available. No data available.

Stabilizes slopes and decreases runoff velocity. Can be incorporated into low impact development plans. Not effective when drainage patterns are altered. Not effective when vegetative areas on perimeter are destroyed. Practiced at virtually all construction sites. No data available on BMP effectiveness. No data available. No data available.

Temp Access Waterways Crossing Reduces risk to damaging streambed from construction equipment tracking. Can be a bridge, culvert, or ford. Bridges and culverts preferred, but more expensive. Data on effectiveness in reducing sediment are not available. No data available. No data available.

Dust Control Important in arid and semi arid regions. Applicable to any construction site. Construction and sequencing and limiting exposure area can reduce problems. Spray on adhesives are recommended. Water application may require near constant attention. Excess water may cause runoff or tracking of mud. Very limited effectiveness information available. Costs can vary widely, depending on local conditions. No data available. No data available. Development Document for Construction and Development Proposed Effluent Guidelines June 2000 5 124 5.2 REFERENCES Adams, J, J. Janatzen, D. Loudenslager. 2000. A Device to Alleviate Pollution from Urban Stormwater. Design Report, Biosystems and Agricultural Engineering, Oklahoma State University, Stillwater, OK.

ASCE. 1999, National Stormwater Best Management Practices (BMP) Database, prepared by the Urban Water Resources Research Council of the American Society of Civil Engineers, prepared for the US EPA, Office of Science and Technology, Washington, DC. http:// www. bmpdatabase. org Barfield, B. J. 2000. Presentation on Nonpoint Source Sediment and Stormwater. University of Puerto Rico, San Juan, PR.

Barfield, B. J., Barnhisel, R. I., Powell, J. C., Hirschi, M. C., and Moore, I. D. 1983. Erodibilities and Eroded Size Distribution of Western Kentucky Mine Spoil and Reconstructed Topsoil. Final Report for Title III. Institute for Mining and Minerals Research, University of Kentucky, Lexington, KY.

Barfield, B. J., and Clar, M. 1985. Development of New Design Criteria for Sediment Traps and Basins. Prepared for the Maryland Resource Administration. Annapolis, MD, pp. 33.

Barfield, B. J., Haan, C. T., Stevens, E., and Hayes, J. C., K. F. Holbrook. 2001. "Engineering Design Aids for Sediment Control Practices," Proceedings of the International Symposium on Soil Erosion Research for the 21 st Century. January 3 5, 2001. Honolulu, Hawaii. Symposium Sponsored and Published by American Society of Agricultural Engineers. St. Joseph, MI.

Barfield, B. J. and Hayes, J. C. 1992. Unpublished Results of Field Evaluation of Sediment Controls in South Carolina Construction Operations. Biosystems and Agricultural Engineering, Oklahoma State University, Stillwater, OK.

Barfield, B. J. and Hayes, J. C. 1999. Unpublished Results of Field Evaluation of Sediment Controls in Louisville, KY Construction Operations. Biosystems and Agricultural Engineering, Oklahoma State University, Stillwater, OK Barfield, B. J., Hayes, J. C., Fogle, A. W., and Kranzler, K. A. 1996. "The SEDIMOT III  Model of Watershed Hydrology and Sedimentology," Proceedings of Fifth Federal Interagency Sedimentation Conference, Las Vegas, NV. 1996. Development Document for Construction and Development Proposed Effluent Guidelines June 2000 5 125 Barfield, B. J., Moore, I. D., and Williams, R. G. 1979. "Sediment Yield in Surface Mined Watersheds," Proceedings Symposium on Surface Mine Hydrology, Sedimentology, and Reclamation. College of Engineering, University of Kentucky, Lexington, KY.

Barrett, M. E., Kearney, J. E., McCoy, T. G., Malina, J. F., Charbeneau, R. J. and Ward, G. H. 1995. An Evaluation of the Use and Effectiveness of Temporary Sediment Controls. Technical Report CRWR 261, Center for Research in Water Resources, The University of Texas at Austin, Austin, TX 78712.

Benik, S. R., B. N. Wilson, D. D. Biesboer, B. Hanse, and D. Stenlund. 1998. The Efficacy of Erosion Control Products at a MN/ DOT Construction Site. Paper No. 982156, American Society of Agricultural Engineers, St. Joseph, MI Blench, T. 1970. Regime Theory Design of Canals with Sand Beds. Proceedings of the American Society of Civil Engineers. 96( IR2): 205 213.

Britton, S. L., Robinson, K. M., and Barfield, B. J. 2001. Modeling the Effectiveness of Silt Fence. Proceedings 7th Federal Interagency Sedimentation Conference, Reno, NV.

Brown, W. and D. Caraco. 1997. "Muddy Water In  Muddy Water Out?". Article No. 52 in The Practice of Watershed Protection. Center for Watershed Protection, Ellicott City, MD. 2000. http:// www. stormwatercenter. net Brown, W. and T. Schueler. 1997. The Economics of Stormwater BMPs in the Mid Atlantic Region. Prepared for: Chesapeake Research Consortium. Edgewater, MD. Center for Watershed Protection, Ellicott City, MD.

Brown, W., D. Caraco, R. Claytor, P. Hinkle, H. Y. Kwon, T. Schueler, C. Swann, and J. Zielinski. 1998. Better Site Design: A Handbook for Changing Development Rules in Your Community. Prepared by Center for Watershed Protection, Ellicott City, MD, for the Site Planning Roundtable.

Caraco, D. S. 1997. "Keeping Soil in Its Place." Article No. 55 in The Practice of Watershed Protection. Center for Watershed Protection, Ellicott City, MD. 2000. http:// www. stormwatercenter. net CWP. 1996. Design of Stormwater Filtering Systems. Prepared for Chesapeake Research Consortium, Solomons, MD, and U. S. EPA Region 5, Chicago, IL, by Center for Watershed Protection, Ellicott City, MD.

Chang, H. H. 1988. Fluvial Processes in River Engineering. Wiley Interscience, New York, 432 p. Development Document for Construction and Development Proposed Effluent Guidelines June 2000 5 126 Claytor, R. 1997. "Practical Tips for Construction Site Phasing." Article No. 54 in The Practice of Watershed Protection. Center for Watershed Protection, Ellicott City, MD. 2000. http:// www. stormwatercenter. net Corish, K. 1995. Clearing and Grading Strategies for Urban Watersheds. Environmental Land Planning Series. Publ. No. 95704. Metropolitan Washington Council of Governments, Washington, DC. http:// www. mwcog. org.

Coyle, J. J. (USDA). 1979. "Grassed Waterways and Outlets". Engineering Field Manual for Conservation Practices. U. S. Department of Agriculture, Soil Conservation Service (SCS). Ch 7. p. 7 7.

Dorman, M. E., J. Hartigan, R. F. Steg and T. Quasebarth. 1989. Retention, Detention and Overland Flow for Pollutant Removal from Highway Stormwater Runoff. Vol. 1. Research Report. Federal Highway Administration. FHWA/ RD 89/ 202. Also in: "Performance of Grassed Swales along East Coast Highways." Article No. 114 in The Practice of Watershed Protection. Center for Watershed Protection, Ellicott City, MD. 2000. http:// www. stormwatercenter. net Ellis, B. 1998. A Further Guide to Swales: Costs of Operation and Maintenance. PERMEATE. Scottish Environmental Protection Agency, Stirling, Scotland. http:// www. sepa. org. uk/ guidance/ scontrol/ swales. htm Entry, J. A., and R. E. Sojka. 1999. Polyacrylamide Application to Soil Reduces the Movement of Microorganisms in Water. In 1999 Proceedings of the International Irrigation Show, Irrigation Association, Orlando, FL, November 9, 1999, pp. 93 99.

Ettinger, C. E. and J. E. Lichty. 1979. Evaluation of Performance Capability of Surface Mine Sediment Ponds. Final Report on Contract Number 68 03 2677, Industrial Environmental Research Laboratory.

Faircloth, W. 1999. "Searching for a Practical, Efficient, Economical Sediment Basin." In Proceeding of the 30 th Conference of the International Erosion Control Association, Nashville, TN, Feb. 22 26, pp. 272 282.

Fifield, J. 2000. Designing for Effective Sediment and Erosion Control on Construction Sites. Forester Press, Santa Barbara, CA.

Fisher, L. S. and Jarrett, A. R. 1984. "Sediment Retention Efficiency of Synthetic Filter Fabric". Transactions of the American Society of Agricultural Engineers. 30( 1): 82 89. Development Document for Construction and Development Proposed Effluent Guidelines June 2000 5 127 Foster, G. R., Young, R. A., and Neibling, W. H. 1985. "Sediment Composition for Nonpoint Source Pollution Analyses." Transaction of the American Society of Agricultural Engineers. 28( 1): 133 146.

Goldberg. 1993. Dayton Avenue Swale Biofiltration Study. Seattle Engineering Department, Seattle, WA.

Griffin, M. L., Barfield, B. J., and Warner, R. C. 1985. "Laboratory Studies of Dead Storage in Sediment Ponds". Transactions of the American Society of Agricultural Engineers. 28( 3): 799 804.

Haan, C. T., Barfield, B. J., and Hayes, J. C. 1994. Design Hydrology and Sedimentology for Small Catchments. Academic Press, San Diego, CA.

Harding, M. V. 1990. Erosion Control Effectiveness: Comparative Studies of Alternative Mulching Techniques. Environmental Restoration, pp. 149 156, as cited in USEPA. 1993. Guidance Specifying Management Measures for Sources of Nonpoint Pollution in Coastal Waters. EPA 840 B 92 002. U. S. Environmental Protection Agency, Office of Water, Washington, DC.

Harper, H. 1988. Effects of Stormwater Management Systems on Groundwater Quality. Final Report. Environmental Research and Design, Inc. Prepared for Florida Department of Environmental Regulation. Also in: "Runoff and groundwater dynamics of two swales in Florida. Article No. 113 in The Practice of Watershed Protection. Center for Watershed Protection, Ellicott City, MD. 2000. http:// www. stormwatercenter. net Hayes, J. C., B. J. Barfield and R. I. Barnhisel. 1984. Performance of Grass Filters under Laboratory and Field Conditions. Transactions of the American Society of Agricultural Engineers 27( 5): 1321 1331.

Hayes, J. C. and Barfield, B. J. 1995. "Engineering Aids and Design Guidelines for Control of Sediment in South Carolina". In South Carolina Stormwater and Sediment Control Handbook for Land Disturbance Activities. South Carolina Department of Health and Environmental Control. Columbia, SC.

Hayes, J. C., Akridge, A. L., Barfield, B. J. and Holbrook, K. F. 2001. "Simplifying Design of Sediment Controls in Jefferson County, Kentucky". In Proceedings of Soil Erosion Research for the 21st Century: An International Symposium and Exhibition, Honolulu, HI, January 2001. Sponsored by the American Society of Agricultural Engineers. Development Document for Construction and Development Proposed Effluent Guidelines June 2000 5 128 Herrera, N. M. and G. K. Felton. 1991. "Hydraulics of Flow through a Rockfill Dam Using Sediment Free Water." Transactions of the American Society of Agricultural Engineers. 34( 3): 871 875.

Heyer, T. No Date. Vegetative Measures for Streambank Stabilization. U. S. Department of Agriculture, Forest Service, St. Paul, MN.

Hirschi, M. C. 1981. "Efficiency of Small Sediment Controls." Unpublished Agricultural Engineering File Report, Agricultural Engineering, University of Kentucky, Lexington, KY. (Details of the report are given in Chapter 9 of Haan et al, 1994).

Holbrook, K. F., Hayes, J. C. and Barfield, B. J., and A. W. Fogle. 1998. "Engineering Aids and Design Guidelines for Control of Sediment in South Carolina," In Proceedings of the International Erosion Control Association Conference. February 1998.

IDNR. 1992. Indiana Handbook for Erosion Controls in Developing Areas, Guidelines for Protecting Water Quality through the Control of Soil and Erosion and Sedimentation on Construction Sites. Division of Soil Conservation, Indiana Department of Natural Resources, Indianapolis, IN.

Jarrett, A. 1999. "Designing Sedimentation Basins for Better Sediment Capture". In Proceeding of the 30 th Conference of the International Erosion Control Association, Nashville, TN, Feb. 22 26, pp. 218 233.

Kay Shoemake, J, M. Watwood, R. Sojka, and R. Lentz. 2000. "Soil Amidase Activity in Polyacrylamide (PAM) Treated Soils and Potential Activity toward Common Amide Containing Agrochemicals". Biology and Fertility of Soils 31( 2): 183 186.

Kercher, W. C., J. C. Landon and R. Massarelli. 1983. "Grassy Swales Prove Cost Effective for Water Pollution Control. Public Works 16: 53 55.

Knisel, W. G., ed. 1980. CREAMS: A Field Scale Model for Chemicals, Runoff, and Erosion from Agricultural Management Systems. U. S. Department of Agriculture, Conservation Research Report No. 26, 640 pp.

Koon, J. 1995. Evaluation of Water Quality Ponds and Swales in the Issaquah/ East Lake Sammamish Basins. King County Surface Water Management and Washington Department of Ecology, Seattle, WA.

Kouwen, N. 1990. Silt Fences to Control Sediment on Construction Sites. Technical Publication MAT 90 03, Research and Development Branch, Ontario Ministry of Transportation, 1201 Wilson Avenue, Downsview, Ontario, Canada M3M 1J8. Development Document for Construction and Development Proposed Effluent Guidelines June 2000 5 129 Lane, E. W. 1955. "The Importance of Fluvial Geomorphology in Hydraulic Engineering". Proceedings of the American Society of Civil Engineers, 81: 1 17.

Leopold, Luna B., M. Gordon Wolman, and John P. Miller, 1964. Fluvial Processes in Geomorphology. Dover Publications, Inc. Mineola, NY.

Lindley, M., B. J. Barfield, J. Ascough, B. N. Wilson, and E. Stevens. 1998. "The Surface Impoundment Element for WEPP". Transactions of the American Society of Agricultural Engineers. 41( 3): 555 564.

Masters, A., K. A. Flahive, S. Mostaghimi, D. Vaughan, A. Mendez, M. Peterie, S. Radke. 2000. A Comparative Investigation of the Effectiveness of Polyacrylamide (PAM) for Erosion Control in Urban Areas. Paper No. 002176, American Society of Agricultural Engineers, St. Joseph, MI, pp. 21.

McBurnie, J. C., Barfield, B. J., Clar, M. L. and Shaver, E. 1990. "Maryland Sediment Detention Pond Design Criteria and Performance". Applied Engineering in Agriculture. 6( 2): 167 173.

MDE. 1994. Maryland Standards and Specifications for Soil Erosion and Sediment Control. Water Management Administration, Maryland Department of the Environment, Soil Conservation Service, and State Soil Conservation Committee, Baltimore, MD.

NAHB. No Date. NAHB Research Center Storm Water Runoff & Nonpoint Source Pollution Control Guide for Builders and Developers. National Association of Home Builders, Washington, DC.

NCDNR. 1988. North Carolina Erosion and Sediment Control Planning and Design Manual. North Carolina Sedimentation Control Commission, the North Carolina Department of Natural Resources and Community Development, and the North Carolina Agricultural Extension Service, Raleigh, NC.

Oakland, P. H. 1983. "An Evaluation of Stormwater Pollutant Removal through Grassed Swale Treatment." In Proceedings of the International Symposium of Urban Hydrology, Hydraulics and Sediment Control, H. J. Sterling, Lexington, KY.

Occoquan Watershed Monitoring Laboratory. 1983. Final Report: Metropolitan Washington Urban Runoff Project. Prepared for the Metropolitan Washington Council of Governments. Manassas, VA. Development Document for Construction and Development Proposed Effluent Guidelines June 2000 5 130 Pitt, R. and J. McLean. 1986. Toronto Area Watershed Management Strategy Study: Humber River Pilot Watershed Project. Ontario Ministry of Environment and Energy, Toronto, Ontario, Canada.

Roa Espinosa, A., G. D. Bubenzer, and E. S. Miyashita. 2000. Sediment and Runoff Control on Construction Sites Using Four Application Methods of Polyacrylamide Mix. National Conference on Tools for Urban Water Resource Management and Protection, Chicago, IL, February 7 10, 2000, pp. 278 .

Renard, K. G., Foster G. R., Weesies, G. A., McCool, KD. K. and Yoder D. C. 1994. Predicting Soil Erosion by Water— A Guide to Conservation Planning with the Revised Universal Soil Loss Equation (RUSLE). Agricultural Research Service Publication, U. S. Department of Agriculture.

Rosgen, D. L., 1996. Applied River Morphology. Wildland Hydrology, Pagosa Springs, CO.

Seattle Metro and Washington Department of Ecology. 1992. Biofiltration Swale Performance: Recommendations and Design Considerations. Publication No. 657. Water Pollution Control Department, Seattle, WA. Also in: Watershed Protection Techniques. Fall 1994 1( 3): 117 119.

SCDHEC. 1995. South Carolina Stormwater Management and Sediment Reductions Regulations. In South Carolina Stormwater Management and Sediment Control Sedimentology Resource, South Carolina Department of Health and Environmental Control. Columbia, SC.

Schumm, S. A. 1977. The Fluvial System. John Wiley and Sons, New York. 338 pp.

Simons, D. B., and M. L. Albertson, 1960. "Uniform Water Conveyance Channels in Alluvial Material." Proceedings of the American Society of Civil Engineers. 86( HY5): 33 71.

Smiley, J., and C. T. Haan. 1976. "The Dam Problem of Urban Hydrology". Proceedings of the National Symposium on Urban Hydrology, Hydraulics, and Sediment Control. College of Engineering, University of Kentucky, Lexington, KY.

Smolen, M. D., D. W. Miller, L. C. Wyall, J. Lichthardt, and A. L. Lanier. 1988. Erosion and Sediment Control Planning and Design Manual. North Carolina Sedimentation Control Commission and North Carolina Department of Natural Resources and Community Development, Raleigh, NC. Development Document for Construction and Development Proposed Effluent Guidelines June 2000 5 131 Snodgrass, W. J., B. W. Kilgour, L. Leon, N. Eyles, J. Parish, and D. R. Barton. 1998. "Applying Ecological Criteria for Stream Biota and an Impact Flow Model for Evaluation of Sustainable Urban Water Resources in Southern Ontario". In: Sustaining Urban Water Resources in the 21st Century. Proceedings for an Engineering Foundation Conference. Edited by A. C. Rowney, P. Stahre, and L. A. Roesner. Malmo, Sweden. September 7 12 1997.

Stahre, P., and B. Urbonas. 1990. Stormwater Detention For Drainage, Water Quality, and CSO Management. Prentice Hall, Englewood Cliffs, NJ.

SWRPC. 1991. Costs of Urban Nonpoint Source Water Pollution Control Measures. Technical report no. 31. Southeastern Wisconsin Regional Planning Commission, Waukesha, WI.

Tobiason, S., D. Jenkins, E. Molash, and S. Rush. 2000. "Polymer Use and Testing for Erosion and Sediment Control on Construction Sites: Recent experience in the Pacific Northwest". In: Proceedings of Conference 31. International Erosion Control Association. Palm Spring, CA, February 21 25, 2000, pp. 41 52.

Tapp, J. S., and Barfield, B. J. 1986. "Modeling the Flocculation Process in Sediment Ponds". Transactions American Society of Agricultural Engineers. 29( 3): 741 747.

Tapp, J. S., Barfield, B. J., and Griffin, M. L. 1981. Predicting Suspended Solids Removal in Pilot Scale Sediment Ponds Utilizing Chemical Flocculation. Research Report IMMR 81/ 063, Institute for Mining and Minerals Research, University of Kentucky, Lexington, KY.

UNEP. 1994. Guidelines for Sediment Control Practices in the Insular Caribbean. CEP Technical Report No. 32. UNEP Caribbean Environment Programme, Kingston, Jamaica. http:// www. cep. unep. org/ pubs/ techreports/ tr32en/ content. html USAF. 1998. USAF Landscape Design: Erosion Control Measures. U. S. Air Force, St. Paul, MN. http:// www. afcee. brooks. af. mil/ ldg/ s18erosioncontrol/ c03process. html USDOT. 1995. Best Management Practices for Erosion and Sediment Control. Report No. FHWA FLP 94 005. Eastern Federal Lands Highway Design, U. S Department of Transportation, Sterling, VA.

USDA and NRCS, 1985. National Engineering Handbook. Natural Resources Conservation Service, Soil Conservation Services. Development Document for Construction and Development Proposed Effluent Guidelines June 2000 5 132 USEPA. 1971. Control of Sediment Resulting from Construction of Highways and Land Development. U. S. Environmental Protection Agency, Washington, DC.

USEPA. 1992. Storm Water Management for Construction Activities: Developing Pollution Prevention Plans and Best Management Practices. EPA 832 R 92 005. U. S. Environmental Protection Agency, Office of Water, Washington, DC.

USEPA. 1992. Storm Water Management for Industrial Activities: Developing Pollution Prevention Plans and Best Management Practices. EPA 832 R 92 006. U. S. Environmental Protection Agency, Office of Water, Washington, DC.

USEPA. 1993. Guidance Specifying Management Measures for Sources of Nonpoint Pollution in Coastal Waters. EPA 840 B 92 002. U. S. Environmental Protection Agency, Office of Water, Washington, DC.

USEPA. 2000. Urban Nonpoint Source Management Measure Guidance  Draft. U. S. Environmental Protection Agency, Office of Water, Washington, DC.

Vanderwel, D. and S. Abday. 1998. An Introduction to Water Erosion Control. Alberta, Agriculture, Food and Rural Development, Alberta, Canada.

VDCR. 1995. Virginia Erosion & Sediment Control Field Manual. Second Edition. Virginia Department of Conservation and Recreation, Division of Soil and Water Conservation, Richmond, VA.

VDCR. 2001. Virginia Erosion and Sediment Control Law, Regulations, and Certification Regulations. Virginia Department of Conservation and Recreation, Division of Soil and Water Conservation, Richmond, VA.

Wang, T., D. Spyridakis, B. Mar and R. Horner. 1981. Transport, Deposition and Control of Heavy Metals in Highway Runoff. FHWA WA RD 39 10. Department of Civil Engineering. University of Washington, Seattle, WA.

Ward, A. D., Haan, C. T., and Barfield, B. J. 1977. Simulation of the Sedimentology of Sediment Detention Basins. Research Report No. 103, Water Resources Research Institute, University of Kentucky, Lexington, KY.

Ward, A. D., Haan, C. T., and Tapp, J. S. 1979. The DEPOSITS Sedimentation Pond Design Manual. OISTL, Institute for Mining and Minerals Research, University of Kentucky, Lexington, KY. Development Document for Construction and Development Proposed Effluent Guidelines June 2000 5 133 Washington State Department of Ecology (WDEC). 1992. Stormwater Management Manual for the Puget Sound Basin. Technical Manual. Washington State Department of Ecology, Olympia, WA.

Welborn, C., and J. Veenhuis. 1987. Effects of Runoff Controls on the Quantity and Quality of Urban Runoff in Two Locations in Austin, TX. U. S. Geological Survey Water Resources Investigations Report. 87 4004, pp. 88.

Williams, J. R. No Date. "Sediment Yield Prediction with Universal Equation Using Runoff Energy Factor". Present and Prospective Technology for Predicting Sediment Yields and Sources. Publication ARS S 40, Agricultural Research Service, U. S. Department of Agriculture, Washington, DC.

Wilson, B. N., and Barfield, B. J. 1984. "A Sediment Detention Pond Model Using CSTRS Mixing Theory." Transactions American Society of Agricultural Engineers. 27( 5): 1339 1344.

Wilson, B. N., Barfield, B. J., and Moore, I. D. 1982. A Hydrology and Sedimentology Watershed Model. Department of Agricultural Engineering, University of Kentucky, Lexington, KY.

Wischmeier, W. H. and D. D. Smith. 1965. Predicting Rainfall Erosion Losses From Cropland East of the Rocky Mountains Guide for Selection of Practices for Soil and Water Conservation. U. S. Department of Agriculture, Agricultural Handbook No. 282. 47 pp.

Wishowski, J. M., Mamo, M., and Bubenzer, G. D. 1998. Trap Efficiencies of Filter Fabric Fence. Paper No 982158, American Society of Agricultural Engineers, St. Joseph, MI.

Wyant, D. C. 1980. Evaluation of Filter Fabric for Use as Silt Fences. VA Highway and Transportation Research Council, Richmond, VA.

WYDEQ. 1999. Urban Best Management Practices for Nonpoint Source Pollution. Point and Nonpoint Source Programs, Water Quality Division, Wyoming Department of Environmental Quality, Cheyenne, WY. http:// deq. state. wy. us/ wqd/ watershed/ 92171. pdf Yousef, Y., M. Wanielista, H. Harper, D. Pearce and R. Tolbert. 1985. Best Management Practices: Removal of Highway Contaminants by Roadside Swales. Final report. University of Central Florida. Florida Department of Transportation. Orlando, FL. Also in: "Pollutant Removal Pathways in Florida Swales". Watershed Protection Techniques. Fall 1995. 2( 1): 299 301. Development Document for Construction and Development Proposed Effluent Guidelines June 2000 5 134 Yu, S., S. Barnes and V. Gerde. 1993. Testing of Best Management Practices for Controlling Highway Runoff. Virginia Transportation Research Council. FHWA/ VA 93 R16, pp. 60. Also in: Performance of Grassed Swales Along East Coast Highways. Article No. 114 in The Practice of Watershed Protection. Center for Watershed Protection, Ellicott City, MD. 2000. http:// www. stormwatercenter. net Development Document for Construction and Development Proposed Effluent Guidelines June 2002 6 1 SECTION 6: REGULATORY DEVELOPMENT AND RATIONALE In this section, the methodology used by EPA to develop regulatory options for the construction and land development industry is described. EPA methodology first evaluated the pollutants discharged from the industry and evaluated existing Federal, State and local control strategies designed to manage impacts. Based on this analysis, EPA was able to identify several key components of existing regulatory strategies that would be applicable for national effluent guidelines regulations and develop regulatory options around these existing strategies. Following development of regulatory options, EPA evaluated the costs and environmental benefits of several options and determined the appropriate option for proposal based on factors such as total costs, monetized and non monetized environmental benefits, ease of implementation, industry financial impacts, and industry acceptance. The following sections describe the components of this process involving identification of impacts, evaluation of available control strategies, and formulation of regulatory options. Costs of regulatory options are discussed in Section 7 of this document while a description of the environmental benefits estimation and industry financial analyses can be found in the other supporting documents of this regulation (USEPA, 2002 and 2002a).

6.1 IDENTIFICATION OF INDUSTRY IMPACTS In developing effluent guidelines for controlling storm water discharges associated with construction and land development activities, EPA identified pollutants that are attributable to the industry. In addition to pollutants discharged from construction sites and from long term storm water discharges, EPA also looked at the broader range of environmental impacts that the land development process influences and that could potentially be addressed under effluent guidelines regulations. These categories include physical impacts to receiving streams due to the increased frequency of high flow rates and associated discharge of sediment, as well as thermal impacts to receiving waters due to the increased temperature of storm water discharges.

These analyses helped EPA to develop regulatory options and associated estimates of costs and benefits for temporary erosion and sediment controls. This approach allowed for the evaluation of different combinations of regulatory options when developing an overall regulatory strategy for this industry, with different combinations addressing various impact areas.

6.1.1 Pollutant Indicators When determining which pollutants to assess, EPA applied the following priorities for construction storm water discharges:

° Focus on pollutants directly attributable to the industry, using indicator pollutants where necessary; Development Document for Construction and Development Proposed Effluent Guidelines June 2002 6 2 ° Focus on pollutants most commonly encountered under most settings, (i. e., not to preconstruction site contamination issues or accidental discharges); ° Focus on pollutants that are most manageable given the current suite of available technologies; and ° Focus on pollutants that can be addressed under the authority of effluent guidelines.

EPA conducted an extensive evaluation of the literature to identify pollutants present in storm water discharges from construction and land development sites. While the literature contains extensive information on pollutants present in storm water discharges from urban areas, there were little data available on pollutants present in storm water discharges from construction sites during the active construction phase other than for sediment, TSS and turbidity. This is not surprising, since construction site storm water management is primarily concerned with the control of solids from exposed soil areas. There is the potential for other pollutants to be discharged from construction sites depending on factors such as prior land uses. For example, if the prior land use was agriculture, there is the potential for discharge of pollutants such as nutrients and pesticides. Likewise, areas of redevelopment that occur on sites where previous land uses included industry could discharge pollutants such as organics and metals. In addition, pollutants such as metals and nutrients can be present in native site soils, and could be discharged from construction sites. However, EPA was not able to identify sufficient data in the literature to warrant development of controls specific to pollutants other than sediment, TSS and turbidity in storm water discharges from construction sites. Some literature suggests that pollutants adhere to sediment so regulating TSS should also act as a control for other pollutants.

There are extensive data in the literature describing pollutants present in storm water discharges from urban areas. The most comprehensive evaluation of urban storm water was the Nationwide Urban Runoff Program (NURP) (USEPA, 1983). While somewhat dated, the NURP results are still valid, and serve as a primary means of characterizing urban runoff pollutants. In addition to NURP, a variety of other analyses conducted over the past 20 years have contributed greatly to the understanding of pollutants present in urban storm water runoff. Literally thousands of references can be found in the literature summarizing hundreds of studies evaluating urban runoff pollutant levels. As a result, there are sufficient data available to identify the major pollutants expected to be discharged from new land development activities. Based on these data sources, EPA identified sediments (measured as TSS), nutrients and metals as pollutants of concern for this industry. EPA also evaluated the inclusion of organics, pesticides, and bacteria as potential pollutants of concern, but the literature indicates that control of these pollutants through conventional storm water management strategies is potentially much more difficult, and that there are little data linking their presence in storm water discharges directly with new land development activities. Source control may factor greatly into controlling these pollutant sources.

Although EPA identified a number of pollutants of concern for this industry, EPA did not develop regulatory options specifically targeted at controlling each of these individual pollutants. Development Document for Construction and Development Proposed Effluent Guidelines 1 Not all pollutant indicators listed above are directly used by EPA in its benefits assessment, or in developing the C& D effluent guidelines. Nevertheless, EPA has collected data to estimate all of the measures for potential future consideration of this and other industries/ activities.

June 2002 6 3 Instead, EPA chose to develop regulatory options using an indicator pollutant, TSS. While TSS levels may not be directly correlated with all pollutants of concern, it is certainly the most widely reported parameter in the literature due to its relative ease of collection and low cost. In addition, design of management systems for the control of TSS will likely result in control of pollutants such as sediment, nutrients and metals that are present in the solid phase (attached to sediments). The one pollutant of concern that may not have a strong correlation with TSS is turbidity, since particles that contribute to turbidity may not be removed through conventional storm water management practices that control TSS. Particles that contribute to turbidity may be of such a fine grain that they will not be removed by the mechanisms whereby most BMPs operate, mainly settling and filtration.

EPA's assessment of pollutant loadings for the industry was based on mathematical models. These models were developed using analyses prepared by EPA for the NPDES Phase II rulemaking (USEPA, 1999), established hydrologic principles and storm water monitoring data from the literature. EPA estimated annual loadings with and without effluent guidelines from construction site storm water discharges using 225 site models which varied based on location, site size and site slope. In its assessment of the industry, EPA elected to use the estimated land area constructed annually in the nation for the contiguous states, based on the National Resources Inventory (NRI)( USDA, 2000). EPA did not develop estimates of pollutant loadings for Alaska, Hawaii, and the U. S. territories, due to a several factors, such as a lack of rainfall data and lack of data on annual land development. However, due to the small amount of development that occurs in these areas, the omission of these areas from the analysis is not expected to contribute a significant error to EPA's national estimates.

In developing pollutant loadings of the land development industries, a distinction was made between primary pollutant loadings (e. g., discharge of sediments from disturbed ground surfaces) and secondary pollutant loadings (e. g., loadings resulting from accelerated erosion of streams caused by increased high flows from urbanized land uses). This distinction was made because studies focusing on the impacts of land development have sometimes neglected the secondary pollutant loadings that result when changes to hydrology cause downstream channels to become unstable. The secondary pollutant loadings that occur year after year from increased stream flows have not been well inventoried. 1 Development Document for Construction and Development Proposed Effluent Guidelines 2 Not all physical/ habitat measures listed above are directly used by EPA in its benefits assessment, or in developing the C& D effluent guidelines. Nevertheless, EPA has collected data to estimate all of the measures for potential future consideration of this and other industries/ activities.

June 2002 6 4 6.1.2 Physical/ Habitat Indicators In addition to assessing impacts of the construction and land development industry due to discharge of pollutants in storm water, EPA also developed a methodology for assessing the physical and habitat impacts caused by changes in hydrology and stream flow. Land development activities cause significant alterations in the natural hydrologic regime of developing watersheds. The removal of vegetation, the compaction of soils by construction equipment and the construction of impervious surfaces such as roads, driveways and buildings causes a marked increase in the total volume and peak flow rate of storm water discharges as compared to forested, open and agricultural land uses. As a result, streams receiving storm water discharges will frequently undergo significant channel alterations in order to adjust to the altered hydrologic regime. This alteration results in mobilization of high quantities of sediment and associated water quality problems.

EPA's assessment attempted to develop an impacts time line, predicting when certain impacts will occur. Due to its relatively short duration, construction impacts (or benefits) were assumed to occur within a single year. The assessment of long term impacts was based on the 30 year period immediately following conversion into urban land use. This includes characterization of physical/ habitat impacts related to hydrologic changes (e. g., increased flooding and stream erosion) and changes in runoff characteristics (e. g., runoff thermal signature). In its modeling effort, EPA made assumptions that simplify (spatial and temporally) land development, compressing the period required for land to reach "build out." EPA performed sensitivity evaluations to verify that these simplifications do not distort or abrogate its assessment of potential environmental impacts.

Physical/ Habitat Measures Estimated by EPA 2 include:

° Miles of stream urbanized (located within the area urbanized nationally in a single year) ° Number of new stream crossings expected to become fish migration barriers ° Acres of stream habitat lost to new stream crossings ° Acres of stream side area flooded by the 100 year rainfall event ° Tons of stream bank/ bed sediment removed as a result of increased high flow rate frequency A detailed discussion of EPA's environmental assessment methodology and results is presented in other supporting documents of this rule (USEPA, 2002 and 2002a). Development Document for Construction and Development Proposed Effluent Guidelines June 2002 6 5 6.2 DEVELOPMENT OF REGULATORY OPTIONS In developing effluent guidelines for the construction and development industries, EPA evaluated a variety of state and local programs to identify various management strategies and regulatory components that would be applicable on a national basis. For erosion and sediment control and other temporary BMPs, EPA considered a series of regulatory options. These options are designed to control the discharge of sediment, storm water and other pollutants from sites when construction is taking place. EPA considered a range of options that incorporate varying levels of management and various control strategies. Because long term storm water management is beyond the scope of the controls proposed by EPA, the following discussion only presents information related to options for controlling storm water during the active phase of construction.

The following discussion presents various options that EPA considered.

Codify the EPA Construction General Permit EPA considered an option that would essentially codify the provisions contained in EPA's construction general permit (CGP) (USEPA, 1998) as minimum national standards for erosion and sediment control (i. e., for all states, not only those with EPA as permitting authority) for sites of 5 acres or more of disturbed land. Requirements include preparing a Storm Water Pollution Prevention Plan (SWPPP) or equivalent, provisions for installing and sizing sediment basins on sites with more than 10 acres of disturbed land, requirements for providing cover on exposed soil areas within 14 days after construction activity has ceased, and installation and maintenance of other erosion and sediment control practices and other temporary BMPs on all construction sites, such as silt fencing, seeding and mulching, diversion dikes and berms, sediment traps, storm drain inlet protection, channel liners, erosion control blankets and mats, stabilized construction entrances, litter, trash and debris control, discarded building material control, and concrete truck wash water control.

Numerical Design Requirements EPA considered an option that would establish numerical requirements for the design of sediment basins and traps based on local or regional rainfall patterns and site specific soil types. This options could be similar to existing requirements designed for managing storm water discharges, where sediment controls are sized based on a specified rainfall return frequency (such as the 2 year, 24 hour storm), or a specified runoff frequency (such as the 90th percentile runoff event).

Numerical Pollutant Removal Requirements EPA considered options that would contain numerical requirements for the removal of specific pollutants from construction site runoff. EPA initially considered targeting a variety of pollutants Development Document for Construction and Development Proposed Effluent Guidelines June 2002 6 6 including sediment, TSS, turbidity, nutrients, metals and other priority pollutants, however there are little data available supporting the feasibility of controlling pollutants other than sediment (or associated indicator parameters such as TSS, turbidity, total suspended sediment, or settleable solids). This option could be expressed as either a percent removal through sediment controls (such as sediment basins or traps), or as a total site reduction (incorporating consideration of sheet flow and diffuse runoff in addition to discrete conveyances). In addition to establishing numerical requirements for the control of sediment, EPA preliminarily considered establishing requirements for removing fine grained and slowly or non settleable particles contained in construction site runoff (such as turbidity). This option would likely have relied primarily on chemical treatment of soils or construction site runoff using polymers or coagulants such as alum in order to prevent the non settleable fractions of solids from being transported off site.

Discharge Monitoring EPA considered the inclusion of monitoring requirements for evaluating the effectiveness of erosion and sediment controls. Monitoring of storm water discharges from construction sites could be used to evaluate the effectiveness of individual sediment controls (such as sediment basins), or monitoring the receiving water above and below construction sites. Monitoring requirements could be incorporated with any of the previously discussed regulatory options considered.

Inspection and Certification EPA considered an option that includes mandatory site inspection, maintenance and reporting provisions by site owners and operators in order to improve confidence in the implementation and performance of construction site erosion and sediment controls. These certification provisions may be accomplished either through self inspection by a qualified employee of the owner and operator (such as a professional engineer or person trained in erosion and sediment control techniques) or inspection by a third party (such as a consulting firm). The certification provisions would consist of a checklist type certification form that the permittee would be required to complete at various stages of the project to certify that the provisions contained in the permittee's SWPPP are being implemented. In addition, the permittees would be required to conduct periodic inspections in order to confirm that the permittee is conducting the maintenance necessary to maintain the functionality of BMPs. The specific activities requiring certification include: SWPPP preparation; installation of perimeter controls and sediment controls; site inspections every 14 days; final stabilization of exposed soils and removal of temporary erosion & sediment controls. The certification and inspection forms would be retained on the site, and made available to the permitting authority and the public upon request. Development Document for Construction and Development Proposed Effluent Guidelines June 2002 6 7 6.3 REGULATORY OPTIONS DEVELOPED FOR THE PROPOSED RULE 6.3.1 Option 1  Inspection and Certification Option 1 proposed by EPA would establish the site inspection and certification provisions discussed above as minimum requirements for all construction sites subject to the NPDES storm water regulations. This includes sites from 1 up to 5 acres that will be required to obtain a permit once the Phase II regulations are implemented and sites 5 acres or greater that are required to obtain a permit under the Phase I regulations. The permittee would be required to conduct periodic inspections and provide certifications as to certain activities (such as SWPPP preparation, BMP installation, periodic maintenance, etc.). Under this option, these inspections and certifications would be performed by a qualified professional, such as a registered professional engineer or person trained in erosion and sediment control. The permittee may provide self certifications if qualified.

The specific inspection and certification provisions can be found in the proposed rule language and are summarized below:

Site log book. The permittee would be required to maintain a record of site activities in a site log book. The specific requirements and information contained in the log book consists of the following:

(1) A copy of the site log book would be required to be maintained on site and be made available to the permitting authority upon request. EPA recommends that the permittee also make a copy of the site log book available to the public upon request within a reasonable period;

(2) In the site log book, the permittee shall certify, prior to the commencement of construction activities, that any plans required by the permit meet all Federal, State, Tribal and local erosion and sediment control requirements and are available to the permitting authority;

(3) The permittee would be required to have a qualified professional conduct an assessment of the site prior to groundbreaking and certify that the appropriate BMPs described in plans required by the permit have been adequately designed, sized and installed to ensure overall preparedness of the site for initiation of groundbreaking activities. The permittee would be required to record the date of initial groundbreaking in the site log book. The permittee would also be required to identify and conduct any soil stabilization and BMP maintenance requirements identified in the permit within 48 hours of their identification;

(4) The permittee would be required to post at the site, in a publicly accessible location, a summary of the site inspection activities on a monthly basis. EPA recommends that the permittee provide contact information for obtaining a copy of the site inspection log book; Development Document for Construction and Development Proposed Effluent Guidelines June 2002 6 8 Site Inspections. The permittee or designated agent of the permittee (such as a consultant, subcontractor, or third party inspection firm) would be required to conduct regular inspections of the site and record the results of such inspection in the site log book. Specific inspection provisions include:

(1) After initial groundbreaking, permittees would be required to conduct site inspections at least every 14 calendar days and within 24 hours of the end of a storm event of 0.5 inches or greater. These inspections would be required to be conducted by a qualified professional. During each inspection, the permittee or designated agent would be required to conduct the following activities and record the following information:

(i) Indicate the extent of all disturbed site areas and drainage pathways. Indicate site areas that are expected to undergo initial disturbance or significant site work within the next 14 day period; (ii) Indicate all areas of the site that have undergone temporary or permanent stabilization; (iii) Indicate all disturbed site areas that have not undergone active site work during the previous 14 day period; (iv) Inspect all sediment control practices and note the approximate degree of sediment accumulation as a percentage of the sediment storage volume (for example 10 percent, 20 percent, 50 percent, etc.). Note all sediment control practices in the site log book that have sediment accumulation of 50 percent or more; and (v) Inspect all erosion and sediment control BMPs and note compliance with any maintenance requirements such as verifying the integrity of barrier or diversion systems (e. g., earthen berms or silt fencing) and containment systems (e. g., sediment basins and sediment traps). Identify any evidence of rill or gully erosion occurring on slopes and any loss of stabilizing vegetation or seeding/ mulching. Document in the site log book any excessive deposition of sediment or ponding water along barrier or diversion systems. Note the depth of sediment within containment structures, any erosion near outlet and overflow structures, and verify the ability of rock filters around perforated riser pipes to pass water.

(2) Prior to filing of the Notice of Termination or the end of permit term, the permittee or designated agent would be required to conduct a final site erosion and sediment control inspection. The inspector would be required to certify that the site has undergone final stabilization as required by the permit and that all temporary erosion and sediment controls (such as silt fencing) not needed for long term erosion control have been removed. Development Document for Construction and Development Proposed Effluent Guidelines June 2002 6 9 6.3.2 Option 2  Codify EPA CGP Requirements with Site Inspection and Certification Provisions Option 2 proposed by EPA would require the permittee to prepare a storm water pollution prevention plan (SWPPP) and implement the erosion and sediment controls contained in the EPA CGP. In addition, the permittee would be required to conduct periodic site inspections and provide certifications in a site log book. This option would only apply to sites with 5 or more acres of disturbed land. The details of this option can be found in the proposed rule language and are summarized below:

General Erosion and Sediment Controls Each SWPPP would be required to include a description of appropriate controls designed to retain sediment on site to the extent practicable. These general erosion and sediment controls would be required to be included in the SWPPP described below. The SWPPP would be required to include a description of interim and permanent stabilization practices for the site, including a schedule of when the practices will be implemented. Stabilization practices may include:

(1) Establishment of temporary or permanent vegetation;

(2) Mulching, geotextiles, or sod stabilization;

(3) Vegetative buffer strips;

(4) Protection of trees and preservation of mature vegetation.

EPA recommends that all controls be properly selected and installed in accordance with sound engineering practices and, when feasible, manufacturer's specifications.

Sediment Controls Operators would be required to design and install structural controls to divert flows from exposed soils, store flows or otherwise limit runoff and the discharge of pollutants from exposed areas and to describe controls in the SWPPP. These controls are as follows:

(1) For common drainage locations that serve an area with 10 or more acres disturbed at one time, the operator would be required to provide a temporary (or permanent) sediment basin that provides storage for a calculated volume of runoff from a 2 year, 24 hour storm from each disturbed acre drained, or equivalent control measures, where attainable until final stabilization of the site. Where no such calculation has been performed, the operator would be required to provide a temporary (or permanent) sediment basin providing 3,600 cubic feet Development Document for Construction and Development Proposed Effluent Guidelines June 2002 6 10 feet of storage per acre drained, or equivalent control measures, where attainable until final stabilization of the site. When computing the number of acres draining into a common location it is not necessary to include flows from off site areas and flows from on site areas that are either undisturbed or have undergone final stabilization where such flows are diverted around both the disturbed area and the sediment basin.

(2) In determining whether a sediment basin is attainable, the operator may consider factors such as site soils, slope, available area on site, etc. In any event, the operator would be required to consider public safety, especially as it relates to children, as a design factor for the sediment basin. Use of alternative sediment controls would be required where site limitations preclude a safe basin design.

(3) For portions of the site that drain to a common location and have a total contributing drainage area of less than 10 acres, the operator would be required to consider installation of sediment traps or other sediment control devices.

(4) Where neither a sediment basin nor equivalent controls are attainable due to site limitations, the operator would be required to install silt fences, vegetative buffer strips or equivalent sediment controls for all down slope boundaries of the construction area and for those side slope boundaries deemed appropriate for individual site conditions.

Pollution Prevention Measures The operator would be required to implement the following pollution prevention measures:

(1) The operator would be required to prevent litter, construction chemicals, and construction debris from becoming a pollutant source in storm water discharges; and (2) The operator would be required to contain construction and building materials in appropriate storage areas and manage the materials to prevent contamination of storm water runoff.

Storm Water Pollution Prevention Plan Permittees would be required to compile Storm Water Pollution Prevention Plans (SWPPPs) prior to groundbreaking at any construction site. In areas where EPA is not the permit authority, operators may be required to prepare documents that may serve as the functional equivalent of a SWPPP. Such alternate documents would satisfy the requirements for a SWPPP so long as they contain the necessary elements of a SWPPP. A SWPPP would be required to incorporate the following information: Development Document for Construction and Development Proposed Effluent Guidelines June 2002 6 11 (1) A narrative description of the construction activity, including a description of the intended sequence of major activities that disturb soils on the site (Major activities include any clearing, grubbing, excavating, grading, soil stockpiling, and utilities and infrastructure installation, or any other activity that results in significant disturbance of soils.);

(2) A general location map (e. g., portion of a city or county map) and a site map. The site map shall include descriptions of the following:

(i) Drainage patterns and approximate slopes anticipated after major grading activities; (ii) The total area of the site and the area of the site that is expected to be disturbed by excavation, clearing, grading and other construction activities during the life of the permit; (iii) Areas that will not be disturbed; (iv) Locations of erosion and sediment controls identified in the SWPPP; (v) Locations where stabilization practices are expected to occur; (vi) Locations of off site material, waste, borrow or equipment storage areas; (vii) Surface waters (including wetlands); and (viii) Locations where storm water discharges to a surface water;

(3) A description of available data on soils present at the site;

(4) A description of BMPs to be used to control pollutants in storm water discharges during construction (5) A description of the general timing (or sequence) in relation to the construction schedule when each BMP is to be implemented;

(6) An estimate of the pre development and post construction runoff coefficients of the site;

(7) The name( s) of the receiving water( s);

(8) Delineation of SWPPP implementation responsibilities for each site owner or operator;

(9) Any existing data that describe the storm water runoff characteristics at the site (such as data that may be collected during a site assessment), and Updating the SWPPP The operator would be required to amend the SWPPP and corresponding erosion and sediment control BMPs whenever: Development Document for Construction and Development Proposed Effluent Guidelines June 2002 6 12 (1) There is a change in design, construction, or maintenance that is expected to have a significant effect on the discharge of pollutants; or (2) Inspections or investigations by site operators, local, State, Tribal or Federal officials indicate that any BMPs described in the SWPPP are ineffective in eliminating or significantly minimizing pollutant discharges.

Site Log Book/ Certification The operator would be required to maintain a record of site activities in a site log book, as part of the SWPPP. The site log book shall be maintained as follows:

(1) A copy of the site log book would be required to be maintained on site and be made available to the permitting authority upon request. EPA recommends that the operator make a copy of the site log book available to the public upon request within a reasonable period;

(2) In the site log book, the operator would be required to certify, prior to the commencement of construction activities, that the SWPPP meets all Federal, State and local erosion and sediment control requirements and is available to the permitting authority;

(3) The operator would be required to have a qualified professional conduct an assessment of the site prior to groundbreaking and certify that the appropriate BMPs and erosion and sediment controls described in the SWPPP have been adequately designed, sized and installed to ensure overall preparedness of the site for initiation of groundbreaking activities. The operator would be required to record the date of initial groundbreaking in the site log book. The operator would be required to certify that the site inspections, soil stabilization activities, and maintenance activities required by the proposed rule have been satisfied within 48 hours of actually meeting such requirements;

(4) The operator would be required to post at the site, in a publicly accessible location, a summary of the site inspection activities on a monthly basis. EPA recommends that the operator provide contact information for obtaining a copy of the SWPPP and a copy of the site inspection log book;

Site Inspections The operator or designated agent of the operator (such as a consultant, subcontractor, or thirdparty inspection firm) would be required to conduct regular inspections of the site and record the results of such inspection in the site log book. The specific activities that would require inspection and certification are: Development Document for Construction and Development Proposed Effluent Guidelines June 2002 6 13 (1) After initial groundbreaking, operators would be required to conduct site inspections at least every 14 calendar days and within 24 hours of the end of a storm event of 0.5 inches or greater. These inspections would be required to be conducted by a qualified professional. During each inspection, the operator or designated agent would be required to record the following information:

(i) On a site map, indicate the extent of all disturbed site areas and drainage pathways. Indicate site areas that are expected to undergo initial disturbance or significant site work within the next 14 day period; (ii) Indicate on a site map all areas of the site that have undergone temporary or permanent stabilization; (iii) Indicate all disturbed site areas that have not undergone active site work during the previous 14 day period; (iv) Inspect all sediment control practices and note the approximate degree of sediment accumulation as a percentage of the sediment storage volume (for example 10 percent, 20 percent, 50 percent, etc.). Record all sediment control practices in the site log book that have sediment accumulation of 50 percent or more; and (v) Inspect all erosion and sediment control BMPs and record all maintenance requirements such as verifying the integrity of barrier or diversion systems (earthen berms or silt fencing) and containment systems (sediment basins and sediment traps). Identify any evidence of rill or gully erosion occurring on slopes and any loss of stabilizing vegetation or seeding/ mulching. Document in the site log book any excessive deposition of sediment or ponding water along barrier or diversion systems. Record the depth of sediment within containment structures, any erosion near outlet and overflow structures, and verify the ability of rock filters around perforated riser pipes to pass water.

(2) Prior to filing of the Notice of Termination or the end of permit term, a final site erosion and sediment control inspection would be required to be conducted by the operator or designated agent. The inspector would be required to certify that the site has undergone final stabilization using either vegetative or structural stabilization methods and that all temporary erosion and sediment controls (such as silt fencing) not needed for long term erosion control have been removed.

Stabilization The operator would be required to initiate stabilization measures as soon as practicable in portions of the site where construction activities have temporarily or permanently ceased, but in no case more than 14 days after the construction activity in that portion of the site has temporarily or permanently ceased. This provision would not apply in the following instances: Development Document for Construction and Development Proposed Effluent Guidelines June 2002 6 14 (1) Where the initiation of stabilization measures by the 14th day after construction activity temporarily or permanently ceased is precluded by snow cover or frozen ground conditions, the operator shall initiate stabilization measures as soon as practicable; (2) Where construction activity on a portion of the site is temporarily ceased, and earthdisturbing activities will be resumed within 21 days, temporary stabilization measures need not be initiated on that portion of the site. (3) In arid areas (areas with an average annual rainfall of 0 to 10 inches), semi arid areas (areas with an average annual rainfall of 10 to 20 inches), and areas experiencing droughts where the initiation of stabilization measures by the 14th day after construction activity has temporarily or permanently ceased is precluded by seasonably arid conditions, the operator shall initiate stabilization measures as soon as practicable.

Maintenance The operator would be required to remove accumulated sediment from sediment traps and ponds identified as having sediment accumulation greater than 50 percent to restore the original design capacity,

6.3.3 Option 3  No Regulation EPA also considered an option that would not establish effluent guidelines requirements for this industry.

6.4 REFERENCES USDA. 2000. 1997 National Resources Inventory. U. S. Department of Agriculture, Natural Resources Conservation Service. Washington, DC. http:// www. nrcs. usda. gov/ technical/ NRI/

USEPA. 1983. Final Report of the Nationwide Urban Runoff Program. U. S. Environmental Protection Agency. Washington DC.

USEPA. 1998. Reissuance of NPDES General Permits for Storm Water Discharges from Construction Activities. (" Construction General Permit.") Federal Register, Vo. 63, No. 31, p. 7858. February 17, 1998. Washington, DC. http:// cfpub. epa. gov/ npdes/ stormwater/ cpermit. cfm? program_ id= 6 USEPA. 1999. Economic Analysis of the Final Phase II Storm Water Rule. U. S. Environmental Protection Agency. Washington, DC. Development Document for Construction and Development Proposed Effluent Guidelines June 2002 6 15 USEPA. 2002. Economic Analysis of Proposed Effluent Limitation Guidelines and New Source Performance Standards for the Construction and Development Category; May 2002. EPA 821 R 02 008. http:// www. epa. gov/ waterscience/ guide/ construction/

USEPA. 2002a. Environmental Assessment for Proposed Effluent Limitation Guidelines and New Source Performance Standards for the Construction and Development Category; May 2002. EPA 821 R 02 009. http:// www. epa. gov/ waterscience/ guide/ construction/ Development Document for Construction and Development Proposed Effluent Guidelines June 2002 7 1 SECTION 7: APPROACH TO ESTIMATING COSTS 7.1 OVERVIEW This section describes EPA's methodology for estimating compliance costs associated with implementing the regulatory options proposed for the construction and land development effluent limitation guidelines (ELG). EPA estimated three distinct cost categories: (1) erosion and sediment control (ESC) costs, including design, installation, operation, and maintenance; (2) administrative costs to permittees for activities such as site inspections and certification activities; and (3) administrative costs to permit authorities to incorporate the effluent guidelines requirements into general permits. Costs contained in categories (1) and (2) are expected to be borne directly by the construction and development industry.

Costs were evaluated individually for 24 site size class and land use types. EPA developed a series of model sites for each land use/ site size class and estimated costs of proposed options for each of these model sites. Using estimates of the population of new construction acreage developed using data from the USDA's National Resources Inventory (NRI), the U. S. Census Bureau, EPA's NPDES Storm Water Phase II rulemaking, and other national data sources (described in Section 3 of this document), EPA summed the model site costs to the national level. A description of this methodology is presented in the Economic Analysis document (USEPA, 2002).

The total costs of the proposed rule options are presented in Table 7 1.

Table 7 1. Total Costs of Proposed Rule Options Option Annual Cost (millions 2000 dollars)

1  Inspection and Certification sites

1 acre 126 2  Codify EPA Construction General Permit (CGP) with Inspection and Certification sites

5 acres 502 3  No Regulation 0 7.2 METHODS FOR ESTIMATING EROSION AND SEDIMENT CONTROL COSTS 7.2.1 OVERVIEW EPA used four land use types to account for variations in construction operations and associated ESCs employed for various development types. For each land use type, EPA evaluated six site size classes to account for economies of scale that might occur with certain best management practice (BMP) design and installation costs (some BMPs are employed only if the site size is Development Document for Construction and Development Proposed Effluent Guidelines June 2002 7 2 greater than a threshold value). EPA also considered regional cost adjustments due to variations in labor, supply, and material costs (see Table 7 2). EPA used an industry standard reference to establish appropriate adjustment factors for regional compliance costs (R. S. Means, 2000).

The costing analysis started by allocating the estimated annual construction acreage and number of model sites developed in Section 4 (see Table 4 21) for one of 19 EPA developed ecoregions shown in Figure 7 1 (see the Environmental Assessment supporting document (EPA, 2002a) for a complete description of the EPA ecoregions). Matrices of standard BMP quantities for the technology based option (Option 2) were developed for the various model site sizes using the NPDES Phase II economic analysis (USEPA, 1999) and the Agency's engineering judgement. By multiplying the two matrices, the total quantity of BMPs for all of the model sites was determined. EPA estimated the unit costs of each BMP element using R. S. Means (2000), and data from "The Economics of Stormwater Treatment: An Update" from the Center for Watershed Protection's (CWP's) book entitled The Practice of Watershed Protection (Schueler, 2000). Regional costs were adjusted using cost adjustment factors from R. S. Means (2000), and data were summed across the different site size categories to determine engineering costs at the national level. Additional costs for factors such as design and contingencies (described in the Economic Analysis) were added to these national costs to arrive at the national cost figures presented in Table 7 1. All costs presented are incremental over current costs to the industry from existing Federal and State requirements.

EPA used a similar approach to estimate administrative costs to permittees for conducting the site inspection and certification provisions contained in Options 1 and 2. EPA estimated the number of site inspections needed and the hours required for conducting site inspections and certifications for each of the model site sizes. By multiplying these hour estimates by a professional labor rate, EPA was able to estimate the total administrative costs to permittees. Similarly, EPA estimated the administrative costs to permitting authorities to revise general permits to incorporate the effluent guideline requirements by multiplying the estimated hours per entity by the number of entities to arrive at the national costs. Development Document for Construction and Development Proposed Effluent Guidelines June 2002 7 3

      Figure 7 1. EPA Ecoregions Source: Composited from Omernik, 1987. Development Document for Construction and Development Proposed Effluent Guidelines June 2002 7 4 Table 7 2. Regional Compliance Cost Adjustment Factors EPA Hydrologic Region Regional Compliance Cost Adjustment Factor 1 0.855 2 0.984 3 0.900 4 0.782 5 0.857 6 0.858 7 0.870 8 1.032 9 0.877 10 0.996 11 0.810 12 0.854 13 0.936 14 0.908 15 1.094 16 1.129 17 1.052 18 1.046 19 1.052 Source: EPA hydrologic regions are composited from Omernik, 1987. Regional compliance cost adjustment factors are computed based on city data from R. S. Means, 2000.

7.2.2 EROSION AND SEDIMENT CONTROL COSTS In this analysis, EPA has built upon a number of previous assessments of ESC practices, including the Economic Analysis of the Final Phase II Storm Water Rule (USEPA, 1999). EPA estimated types and quantities of ESC BMPs that are commonly employed under baseline conditions during construction activities to mitigate impacts from construction site runoff for 24 land use/ site size class models. In addition, in its analysis EPA estimated that requirements Development Document for Construction and Development Proposed Effluent Guidelines June 2002 7 5 contained in existing State construction general permit requirements (or, in the non authorized states, the region specific EPA construction general permits (CGPs) would be fully implemented. Although Phase II is not fully implemented at this time, the requirements will be implemented by the time final action is taken on these proposed effluent guidelines. Furthermore, as proposed Option 2 (the only option for which EPA is establishing technology based requirements) addressed only sites with 5 or more acres of disturbed land, the timing of Phase II implementation is not an issue.

EPA took a model site approach to estimating the baseline ESC usage and quantities of materials, as well as design costs and operation and maintenance (O& M) costs that are expected to be applicable given a range of physical conditions (1 to 7 percent land slopes and different soil types). Table 7 3 lists the construction site BMPs included in the baseline analysis for various site sizes. To establish baseline BMP usage, EPA started with the model site estimates generated during the Phase II rulemaking, scaling up the BMP quantities to sites larger than 5 acres, and adding sediment basins for larger sites. In the final costing analysis of this option, costs for BMPs for sites less than 5 acres were eliminated, consistent with the proposed regulatory requirements for Option 2.

Table 7 3. Construction Site ESC BMP Descriptions and Site Thresholds ESC BMP Description Applicable Site Sizes for ESC BMP Quantity Estimates Silt Fence, Diversion Dike, Construction Entrances, Stone Check Dams > 1 acre Mulch > 1 acre Sediment Traps > 1 acre and < 10 acres Polyacrylamide (PAM) > 1 acres Sediment Basins

10 acres BMP Installation and SWPPP Certifications

1 acre Site Inspections

1 acres To determine costs of the regulatory options, EPA first evaluated a variety of State construction general permits and erosion and sediment control regulations and found that many States have requirements similar to those contained in the EPA construction general permit, which is the Development Document for Construction and Development Proposed Effluent Guidelines 1 Although EPA attempted to obtain comprehensive information, the Agency was not able to verify the presence of the specific components in Table 7 4 for all States. As a result, the absence of an entry does not necessarily mean that the State does not currently have an equivalent requirement.

June 2002 7 6 basis for the requirements contained in Option 2 (see Table 7 4) 1 . In evaluating existing State programs, EPA specifically examined the major provisions contained in Option 2, namely sediment basins designed to provide 3,600 cubic feet per acre of storage; requirements for stabilization of exposed soil areas within 14 days of reaching final grade; and site inspections at least every 14 days. In addition, EPA evaluated whether the annual precipitation in each State is less than 20 inches, since the soil stabilization requirements are linked to this condition. In the final analysis of national costs, EPA adjusted the estimates of the national costs for the effluent guidelines to account for States with programs equivalent to EPA's proposed options. Table 7 5 summarizes the percentage of national costs eliminated due to equivalent State programs. This is only applicable to Option 2, as EPA has not determined that a significant number of States have requirements equivalent to Option 1.

It is expected that on some construction sites there will be some portion of land with steeper slopes and more erosive soils, which will require more intensive management if built upon than is assumed by EPA's model. Also, a State with less than 20 inches of annual rainfall was considered to be equivalent to a State that has the 14 day cover requirement when assessing overall equivalence. Local regulations may require use of ESCs that are more stringent than the Phase I and II requirements. However, EPA expects that the BMPs selected to develop its model sites are representative of baseline conditions for the majority of construction activity across the nation. Development Document for Construction and Development Proposed Effluent Guidelines June 2002 7 7 Table 7 4. Components of Existing State Erosion and Sediment Control Requirements a State Minimum of 3,600 Cubic Feet per Acre Sediment Basin Requirement Inspections Required at Least Every 14 Days 14 Day or Less Stabilization Requirement States with Less than 20 Inches of Precipitation Per Year Alabama Alaska Yes Yes Yes Arizona Yes Yes Yes Yes Arkansas California Yes Yes Yes Colorado Yes Connecticut Yes Yes Yes Delaware District of Columbia Florida Georgia Hawaii Idaho Yes Illinois Yes Indiana Iowa Yes Yes Yes Kansas Kentucky Louisiana Maine Maryland Massachusetts Yes Yes Yes Michigan Minnesota Development Document for Construction and Development Proposed Effluent Guidelines State Minimum of 3,600 Cubic Feet per Acre Sediment Basin Requirement Inspections Required at Least Every 14 Days 14 Day or Less Stabilization Requirement States with Less than 20 Inches of Precipitation Per Year June 2002 7 8 Mississippi Missouri Montana Yes Yes Nebraska Nevada Yes New Hampshire Yes Yes Yes New Jersey New Mexico Yes Yes Yes Yes New York North Carolina North Dakota Yes Ohio Yes Yes Oklahoma Yes Oregon Pennsylvania Yes Yes Yes Rhode Island South Carolina Yes Yes Yes South Dakota Yes Yes Yes Yes Tennessee Yes Yes Yes Texas Yes Yes Yes Utah Yes Yes Yes Yes Vermont Virginia Yes Yes Yes Washington West Virginia Yes Yes Wisconsin Development Document for Construction and Development Proposed Effluent Guidelines State Minimum of 3,600 Cubic Feet per Acre Sediment Basin Requirement Inspections Required at Least Every 14 Days 14 Day or Less Stabilization Requirement States with Less than 20 Inches of Precipitation Per Year June 2002 7 9 Wyoming Yes Yes a. Information is accurate as of May 2002 Table 7 5. State Acreage Equivalent to Proposed Option 2 Equivalent State Acreage for Sites >5 acres Percent of Annual (> 5 acre) Developed Acreage Equivalent Option 2 755,500 41 Once EPA estimated the quantities of ESC BMPs for the model sites, the total baseline cost of BMP installation was calculated from unit costs provided by R. S. Means (2000) and cost curves from "The Economics of Stormwater Treatment: An Update" (Schueler, 2000). R. S. Means provides national average unit costs that include materials, installation, and labor. Typically, users of R. S. Means adjust the national unit costs up or down to obtain their local estimates based on city specific adjustment factors provided by R. S. Means. As described previously, EPA developed and used the regional adjustment factors in Table 7 2 to customize unit costs on an ecoregion basis, not on a city basis. To compute region specific unit costs from the national average value, city specific adjustment factors provided by R. S. Means were converted into ecoregion values. First, State average adjustment factors were estimated based on the values for cities they contained. Then ecoregion values were computed based on area weighting for those states that fell within each ecoregion.

Although R. S. Means is expected to accurately estimate the as built cost for a particular element, in certain cases it might underestimate the cost that a developer or ultimate property owner might need to pay a contractor to construct a particular element. This is due to additional site specific cost factors that a contractor may build into a bid package, such as contingencies, allowances for change orders, additional time and labor for unseen delays due to weather, unanticipated problems with soils, etc. However, for the majority of projects, R. S. Means is expected to provide accurate cost information. In addition, EPA adjusted for contingency costs in its analysis of economic impacts to the industry (see the Economic Analysis document for a description of this methodology).

In calculating the total costs for erosion and sediment control activities, EPA added estimated design, operation, and maintenance costs. Table 7 6 shows design and O& M costs as a fraction of the capital cost of ESC BMPs. These cost ratios were obtained from published sources such Development Document for Construction and Development Proposed Effluent Guidelines June 2002 7 10 as the CWP report and from the Agency's engineering judgement.

In evaluating the proposed rule options, EPA used the model site approach to first determine the baseline compliance costs, then to modify BMP sizing and BMP quantities to assess the incremental costs of regulatory options of the proposed rule. The resulting suite of BMPs evaluated by EPA in establishing costs of the proposed rule are listed in Table 7 7, along with their unit costs. Appendix B contains additional tables indicating EPA's estimates of the standard quantity needed for each BMP listed in Table 7 7, for each land use type and site size. In addition, Appendix B indicates, for key BMPs, the number of equal size BMPs of a single type that EPA estimates will be needed to serve a single site (i. e., a single 200 acre site will be served by four equal size sediment basins, each of which manages 50 acres).

Table 7 6. Construction ESC BMP Design and Operation and Maintenance Costs as a Percentage of Capital Costs Costed Items Effective Life in Years Design Costs as Percent of Construction Cost Estimated O& M as Percent of Original Installation Costs Silt Fence 1 6% 100%

Diversion Dike 1 6% 10%

Mulch 1 6% 2%

Construction Entrance 1 6% 5%

Stone Check Dam 1 6% 5%

Sediment Trap 1 6% 20%

Sediment Basin 1 6% 25%

Polyacrylamide (PAM) 1 6% 0 Development Document for Construction and Development Proposed Effluent Guidelines June 2002 7 11 Table 7 7. Evaluated Construction Site BMPs that Augment the Suite of Baseline BMPs BMP Description Costing Rationale Erosion and Sediment Controls Sediment Basins for Sites

10 acres Standardization to 3,600 cubic feet of storage per watershed acre. Cost based on equation for installing permanent dry detention pond, computed from the equation: [8.16 x (volume required, cu. ft./ number of ponds per site size) 0.78 ] (Schueler, 2000).

Mulch Mulching of any denuded surface would be required within 14 days of reaching final grade, resulting in more frequent mulching of a portion of the site acreage. Cost of mulching is estimated to be $0.23 per square yard for materials/ installation (R. S. Means). For sites larger than 1 acre, mulching is based on the total site acreage less the area where structures are being built (estimated as the site impervious coverage). The maximum coverage for single family and multifamily residential development is 50% of the total site area, assuming the remaining acreage is maintained as open space and/ or permanent vegetation/ cover is installed.

Polyacrylamide (PAM) EPA estimates that a single application of PAM would be used as a temporary stabilization method until final cover can be installed. PAM was estimated to be appropriate for only 20% of construction sites due to physical constraints. PAM is costed at $200 per acre treated based on a survey of commercial vendors and the assumption that its application is similar to that of herbicide for soil treatment ($ 0.04 per square yard based on spraying from truck) (R. S. Means). The acreage treated is equal to the site size times the ultimate impervious area, to a maximum of 50% of the site size.

Site Administration BMPs Site Certifications For each site, certification activities include certification of storm water pollution prevention plan (SWPPP) completion, certification of BMP installations, and certification of final stabilization prior to filing of the notice of termination (NOT). Certification adds an estimated cost of approximately $11 per acre for Options 1 and 2.

Site Inspections For each 10 acre unit in the total site, incremental inspection activities over baseline are: (a) post BMP installation; (b) once during building; and (c) at end of construction (prior to filing of the NOT). Inspection adds an estimated cost of approximately $45 per acre for Options 1 and 2.