Environmental Review Toolkit
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Stormwater Best Management Practices in an Ultra-Urban Setting: Selection and Monitoring

6.3 The Scoping Phase

The scoping phase provides an initial screening analysis of potential structural and nonstructural BMPs. Structural BMPs are generally designed to remove constituents in stormwater runoff, whereas nonstructural measures focus on the prevention of source-related constituent-generating activities from contaminating stormwater (e.g., covering salt piles) and on the removal of constituents that might contaminate stormwater (e.g., streetsweeping). In the scoping phase, the ability of structural and nonstructural BMP options to meet management objectives is evaluated. The scoping phase may address the following questions:

  • Does the BMP address one or more management objectives?
  • Does the BMP provide both stormwater quantity and quality control?
  • Are data available on BMP effectiveness?
  • Is the BMP applicable to site conditions?
  • Does the nonstructural BMP help to reduce long-term structural BMP maintenance requirements?
  • Is the BMP costly to implement?
  • Does the BMP provide auxiliary benefits such as public education?

A number of different factors are used to evaluate BMPs in the scoping phase. Management goals and objectives, the characteristics of the site (in terms of constituent sources and types and general site characteristics), and the characteristics of the BMP provide the framework for evaluating the applicability of both structural and nonstructural BMPs.

6.3.1 Management Goals and Objectives

An effective ultra-urban stormwater management program focuses on meeting well-defined environmental protection goals and public needs in a cost-effective manner. In many cases, an ultra-urban management plan is designed to address multiple environmental and safety concerns at various scales ranging from site-specific to a larger watershed scale. The development and implementation of stormwater management plans are driven by a variety of conditions including public pressure, applicable regulations and policies, downstream impacts on sensitive resources, or a combination of any of these conditions. Within these plans, downstream impacts are usually expressed qualitatively in terms of objective statements such as "control of flooding conditions", "control of stream degradation and associated sediment loadings", "restoration of a water quality impairment", or "protection of aquatic habitat".

Meeting these multiple objectives may require that several potential BMP siting locations be identified and considered. Potential BMPs can be determined for each site location to form a comprehensive management action plan. These selected BMPs, as well as the overall management actions (whether at the site-specific drainage area or at the watershed scale), will contribute to achieving the predefined management objective(s). An in-depth understanding of stormwater management objectives prior to the selection of a BMP or combination of BMPs is essential to the development of a successful management plan. This understanding should facilitate the development of management objectives into measurable indicators or criteria that can be used to screen out nonapplicable BMPs. Table 45 provides a set of potential screening criteria that can be derived for different management objectives.

Typical stormwater management objectives applicable to ultra-urban settings include:

  1. Flood protection.
  2. Reduction in loadings of nonpoint source constituents.
  3. Measures for stabilization of downstream erosion to reduce sediment loading.
  4. Aesthetic enhancement.
  5. Public safety.
  6. Reduced public facilities maintenance costs.
  7. Provisions for recreation.

The numbers shown for each objective are included in the summary tables provided later in this chapter. The objectives provided here will be used to help illustrate which of these objectives may be achieved by the BMPs analyzed during the selection process.

Table 45. Example of How Management Objectives Can be Used to Derive Screening Criteria
Overall Goal Management Objective Measure Potential Evaluation Criteria
Environmental Protection Control of nonpoint source pollution Constituent loadings Maximize percent load reductions
Provide flood protection Peak flow Maintain peak flows at or lower than predevelopment conditions (generally 10- and 100-year storm event)
Protect floodplain areas from development
Control stream stability problems downstream Flow frequency
Flow duration
Reduce velocities and bottom shear stress below erosive levels
Reduce flow frequency and duration to mimic predevelopment levels

6.3.2 Site Characterization

Site characterization includes evaluation of the drainage area to identify runoff and constituent-generating activities and sources, and characterization of the magnitude and the areal extent of each source. Several procedures can be used to assess loadings from ultra-urban areas (USEPA, 1983), including highway runoff in particular (Driscoll et al., 1990), and to define probable impacts on receiving water bodies. Chapters 2 and 4 of this document describe additional site characterization elements that can assist in evaluating the runoff potential and source-specific loading. Characterization of dominant sources and constituents, definition of the constituent fate and transport pathways, and identification of the method and processes by which constituents enter stormwater runoff are key elements supporting the selection of appropriate ultra-urban BMPs.

BMP Selection Based on Site Characterization

The Alaska Marine Lines site, in Seattle, Washington, is an L-shaped property that fronts two waterways. The site was redeveloped to ship, handle, and store cargo containers. Due to the large amount of vehicular and forklift traffic in and around the cargo-handling area, the site was characterized as having high concentrations of petroleum-based contaminants. Sand filters were selected for stormwater treatment based on their proven ability to handle petroleum-based contaminants washed from paved surfaces. In addition, because limited area for the terminal required paving and using the entire upland area available, the sand filter system offered an effective and practical alternative to other BMP designs. Sand filters were conveniently sited along the perimeter of the L-shaped property to treat stormwater runoff entering the Duwamish Waterway (Horner and Horner, 1995).

6.3.3 Screening of Structural BMPs

The screening of structural BMPs is intended to eliminate those BMPs that are obviously impractical, implausible, or ineffective. It is unlikely that any single BMP will be able to completely meet all management objectives; trade-offs between cost and performance almost always occur. Often, more than one BMP will be necessary. The resources and effort required to evaluate these trade-offs make it desirable to remove from consideration any BMPs that do not fulfill -- or do not contribute significantly in combination with other BMPs to fulfilling -- management objectives. The nature and scope of the planned project, water quantity and quality management objectives, and any other limiting management objectives should be used to evaluate the suite of available structural BMPs.

Nature and Scope of Planned Project

The nature of a proposed project in an ultra-urban area often dictates which BMPs are impractical due to size or settings. For example, the placement of an elevated highway over a busy roadway in an ultra-urban setting may present an opportunity to retrofit small stormwater BMPs into an existing drainage system. Developing the list of feasible BMP options for this site would begin with a recognition of its key features, which are (1) limited available surface area, (2) limited airspace between the original roadway and the elevated roadway, and (3) the need to sustain the existing operability of the roadway during BMP installation and maintenance. It would be inappropriate to install area-intensive BMPs like ponds and wetlands at this site, so these can be quickly screened from further consideration. Small BMPs such as infiltration trenches and water quality inlet devices could be considered potentially feasible at this point in the process.

Table 46 indicates which BMPs are most compatible with the ultra-urban setting because of their relatively small footprint, design adaptability, and effectiveness in removing typical constituents from stormwater. It should be noted that BMPs that may not be compatible with ultra-urban settings do have applicability for roadway projects in less urban and nonurban settings where larger land areas are available and greater flexibility in siting BMPs exists.

Table 46. Primary Function of BMPs and Ability to Address Management Objectives
BMP Types Ultra-Urban Compatible Water Quantity Water Quality Constituent Removal Effectiveness
Suspended1 Dissolved1
Infiltration Trench yes no ••• ••º
Infiltration Basin no yes ••• ••º
Bioretention yes no ••• ••º
Extended Detention Wet Pond no yes ••º ••º
Wet Pond no yes ••º •••
Extended Detention Dry Pond no yes ••• ••º
Wetlands no no ••• •••
Underground Detention Tanks yes yes ººº ººº
Underground Sand Filters yes no ••• •ºº
Surface Sand Filters no no ••º •••
Organic Media Filters yes no ••• •••
Vegetated Swales yes no ••º ••º
Vegetated Filter Strips no no •ºº •ºº
Oil-Grit Separators yes no •ºº •ºº
Catch Basin Inserts yes no •ºº •ºº
Manufactured Systems yes no •ºº •ºº
Porous Pavement yes yes •ºº ••º
1Note: Suspended constituents include suspended solids as well as oil/grease, metals, nutrients, and trace organics associated with suspended solids. Dissolved constituents include soluble trace metals, nutrients, and trace organics.
ººº = None, •ºº = Low, ••º = Moderate, ••• = High.

Table 47 provides the site considerations needed to evaluate the feasibility of various BMPs based on the nature and scope of proposed projects. This includes the percent of the drainage area that must be set aside for BMP installation and a consideration of whether the design is dependent on in situ soils. Both of these elements will impact on the screening of structural BMPs.

Table 47. Site Considerations for Structural BMPs
BMP Area Typically Served (ha) Area Required for BMP6 In Situ Soils Minimum Head Requirement 1 (m) Configuration Climate a SignificantFactor?2
Infiltration Trench 0.8-1.6 2-4% dependent 0.9-2.4 off-line/on-line Yes
Infiltration Basin 0.8-8.0 2-4% dependent 0.6-1.2 off-line Yes
Bioretention 0.4-20.0 4-10% independent3 0.6-1.2 off-line/on-line Yes
Detention Ponds 0.8 min 10-20% independent 0.9-1.8 off-line/on-line No
Wetlands 0.4 min 10% dependent 0.3-2.4 off-line/on-line Yes
Detention Tanks4 0.4-0.8 0.5-1% independent 1.5-2.4 off-line No
Underground Sand Filters 0.8-2.0 2-3% independent 0.3-2.4 off-line No
Surface Sand Filters 0.8-2.0 2-3% independent 1.5-2.4 off-line Yes
Organic Media Filters 0.8-2.0 2-3% independent 1.5-2.4 off-line Yes
Vegetated Swales 0.8-1.6 10-20% dependent 0.6-1.8 on-line Yes
Vegetated Filter Strips NA 25%5 dependent negligible on-line Yes
Oil-Grit Separators 0.4-0.8 < 1% independent 0.9-1.8 on-line No
Catch Basin Inserts < 0.4 None independent 0.3-0.6 on-line None
Manufactured Systems 0.4-4 None independent 1.2 on-line None
Porous Pavement 0.8-1.6 NA dependent NA NA NA

Adapted from Claytor and Schueler, 1996; Young et al., 1996; and others.
NA = Not Applicable or Not Available

  1. Either the depth of water in the typical design or the total drop in water level for flow-through designs.
  2. Climate issues to consider include prolonged drought and freeze periods.
  3. When equipped with an underdrain system.
  4. Based on storage of 12.7 mm (0.5 in) of runoff per acre of imperviousness.
  5. Minimum recommended for best treatment efficiency.
  6. Expressed as a percent of the total drainage area, can be modified to accommodate ultra-urban conditions.

Water Quantity and Quality Management Objectives

Local ordinances or state and federal regulations frequently mandate a design level of performance for both water quantity and quality management. For example, a proposed highway project may be required to manage stormwater runoff such that the 25-year peak runoff rate does not exceed the preconstruction condition (Driscoll et al., 1990; Young et al., 1996). The required flood protection and water quantity management for the highway would not be provided by BMPs like oil-grit separators and vegetated filter strips. While these BMPs can facilitate the process of flood protection by providing pretreatment of sediment and other constituents, they alone cannot fulfill the flood protection objectives. BMPs that are obviously unable to fulfill dictated management objectives related to water quantity can be identified using the information in Table 46 as primarily water quality BMPs, and screened out from further consideration. BMPs that can be utilized for pretreatment are supplementary water quality management measures and can be retained for further evaluation.

Water quality control is usually defined by identified pollutants of concern and the desired level of removal expected. Typical constituents of concern associated with management objectives include nitrogen and phosphorus, suspended sediments, and trace toxics such as heavy metals. For highways, an in-depth listing of constituents and their sources can be found in Tables 48 and 49. Due to high levels of imperviousness and road density, stormwater from ultra-urban areas will likely contain similar constituent loadings. Loadings for some constituents, particularly those associated with specialized commercial or industrial land use activities, however, may be significantly different. These specialized land use activities may include the introduction into stormwater of dissolved constituents that are more difficult to remove using structural BMPs.

Table 48. Constituents and Sources in Highway Runoff
Constituent Source
Particulate Pavement wear, vehicles, atmospheric deposition, maintenance activities
Nitrogen, Phosphorus Atmospheric deposition and fertilizer application
Lead Leaded gasoline from auto exhausts and tire wear
Zinc Tire wear, motor oil, and grease
Iron Auto body rust, steel highway structures such as bridges and guardrails, and moving engine parts
Copper Metal plating, bearing and brushing wear, moving engine parts, brake lining wear, fungicides and insecticides
Cadmium Tire wear and insecticide application
Chromium Metal plating, moving engine parts, and brake lining wear
Nickel Diesel fuel and gasoline, lubricating oil, metal plating, bushing wear, brake lining wear, and asphalt paving
Manganese Moving engine parts
Cyanide Anti-caking compounds used to keep deicing salts granular
Sodium, Calcium, Chloride Deicing salts
Sulphates Roadway beds, fuel, and deicing salts
Petroleum Spill, leaks, antifreeze and hydraulic fluids, and asphalt surface leachate

 

Table 49. Constituents of Highway Runoff, Ranges of Average Values Reported in the Literature
Constituent Concentration
(mg/L unless indicated)
Load
(kg/ha/year)
Load
(kg/ha/event)
Solids
Total 437 - 1147   58.2
Dissolved 356 148  
Suspended 45 - 798 314 - 11,862 1.84 - 107.6
Volatile, dissolved 131    
Volatile, suspended 4.3 - 79 45 - 961 .89 - 28.4
Volatile, total 57 - 242 179 - 2518 10.5
Metals (totals)
Zinc .056 - .929 .22 - 10.4 .004 - .025
Cadmium ND - .04 .0072 - .037 .002
Arsenic .058    
Nickel .053 .07  
Copper .022 - 7.0333 .03 - 4.67 .0063
Iron 2.429 - 10.3 4.37 - 28.81 .56
Lead .073 - 1.78 .08 - 21.2 .008 - .22
Chromium ND - .04 .012 - .1 .0031
Magnesium 1.062    
Mercury, x 103 3.22 .007 .0007
Nutrients
Ammonia, total as N .07 - .22 1.03 - 4.6  
Nitrite, total as N .013 - 2.5    
Nitrate, total as N .306 - 1.4    
Nitrite + Nitrate .15 - 1.636 .8 - 8 .078
Organic, total as N .965 - 2.3    
TKN .335 - 55 1.66 - 31.95 .17
Nitrogen, total as N 4.1 9.8 .02 - .32
Phosphorus, total as P .113 - .998 .6 - 8.23  
Miscellaneous
Total coliforms organisms/100 mL 570 - 62000    
Fecal coliforms organisms/100 mL 50 - 590    
Sodium   1.95  
Chloride 4.63 - 1344    
Total organic carbon 24 - 77 31.3 - 342.1 .88 - 2.35
Chemical oxygen demand 14.7 - 272 128 - 3868 2.9 - 66.9
Biological oxygen demand (5 day) 12.7 - 37 30.6 - 164 .98
Polyaromatic hydrocarbon (PAH)   .005 - .018  
Oil and grease 2.7 - 27 4.85 - 767 .09 - .16
Source: Barrett, et al., 1995.

Most structural BMPs rely on sedimentation and infiltration/filtration processes to remove constituents from stormwater. These practices may have a limited effect when dealing with dissolved and highly mobile constituents. The removal effectiveness of structural BMPs on a wide range of potentially harmful, primarily trace organic constituents is not known. Some structural BMPs such as wetland complexes may achieve the removal of dissolved nutrients through biochemical processes such as the nitrification of nitrate-nitrogen or through temporary storage of nutrients in plant tissue. Typical constituents of stormwater runoff, their primary transport phase and their control mechanisms are provided in Tables 48, 49, and 50. The ability of a structural BMP to meet constituent removal criteria depends on the removal mechanisms inherent in its design. Table 46 categorizes BMPs on their general ability to remove two broad categories of pollutants -- suspended constituents and dissolved constituents. Suspended constituents include suspended solids as well as those constituents that can be removed by physical processes (e.g., sedimentation and filtration) including oil and grease, metals, nutrients, and trace organics associated with suspended solids.

Table 50. General Transport and BMP Removal Processes for Selected Constituents
Constituents Primary Transport Phase(s) Primary Control Mechanisms
Suspended Solids
(TSS, VSS)
Particulate Sedimentation (adsorption, settling, precipitation)
Physical filtration
Nutrients
(TP, OP, TKN, NH3, NO3)
Particulate/Dissolved Sedimentation
Physical filtration
Adsorption
Bioaccumulation
Trace Metals
(Zn, Dc, As, Ni, Cu, Pb, Cr)
Particulate/Dissolved Sedimentation
Physical filtration
Adsorption
Trace Organics
(PAHs)
Particulate/Dissolved Sedimentation
Physical filtration
Adsorption
Biodegradation
Oil and Grease Particulate Adsorption
Filtration
Sedimentation
Biodegradation
Bacteria
(Total, Fecal)
Particulate Physical filtration
Sedimentation
Decay (die-off)

Dissolved constituents that are predominately removed through adsorption and biochemical processes include the soluble phases of metals, nutrients, and trace organic constituents. The actual removal performance of individual BMPs will be highly dependent on their hydraulic design and the hydrologic conditions encountered during stormwater treatment. Screening out BMPs that are obviously ineffective for targeted pollutants facilitates the selection of an effective BMP. Detailed information on the demonstrated removal effectiveness of BMPs for specific constituents is provided in Table 51.

Table 51. Pollutant Removal Effectiveness (%)
BMP TSS TP TN NO3 Metals Bacteroa Oil & Grease TPH References
Infiltration Trench1 75 - 99 50 - 75 45 - 70 NA 75 - 99 75 - 98 NA 75 Young et al. (1996)
Infiltration Basin1 75 - 99 50 - 70 45 - 70 NA 50 - 90 75 - 98 NA 75 Young et al. (1996)
Bioretention1 75 50 50 NA 75 - 80 NA NA 75 Prince George's County (1993)
Detention Ponds 46 - 98 20 - 94 28 - 50 24 - 60 24 - 89 NA NA NA City of Austin (1990);
City of Austin (1995);
Harper & Herr (1993);
Gain (1996);
Martin & Smoot (1986);
Young et al. (1996);
Yu & Benetlmouffok (1988);
Yu et al. (1993 & 1994)
Wetlands 65 25 20 NA 35 - 65 NA NA NA USEPA (1993)
Detention Tanks NA NA NA NA NA NA NA NA  
Underground Sand Filters 70 - 90 43 - 70 30 - 50 NA 22 - 91 NA NA NA Bell et al. (1995);
Horner & Horner (1995);
Young et al. (1996)
Surface Sand Filters 75 - 92 27 - 80 27 - 71 0 - 23 33 - 91 NA NA NA City of Austin (1990);
Welborn & Veenhuis (1987)
Organic Media Filters 90 - 95 49 55 NA 48 - 90 90 90 90 Claytor and Schueler (1996);
Steward (1992);
Stormwater Management (1994)
Vegetated Swales 30 - 90 20 - 85 0 - 50 NA 0 - 90 NA 75 NA City of Austin (1995);
Claytor and Schueler (1996);
Kahn et al. (1992);
Yousef et al. (1985);
Yu & Kaighn (1995);
Yu et al. (1993 & 1994)
Vegetated Filter Strips 27 - 70 20 - 40 20 - 40 NA 2 - 80 NA NA NA Yu & Kaighn (1995);
Young et al. (1996)
Oil-Grit Separators 20 - 40 < 10 < 10 NA < 10 NA 50 - 80 NA Young et al. (1996)
Catch Basin Inserts NA NA NA NA NA NA up to 90 NA King County
Manufactured Systems NA NA NA NA NA NA up to 96 NA Bryant et al. (1995)
Porous Pavement 82 - 95 60 - 71 80 - 85 NA 33 - 99 NA NA NA MWCOG (1983);
Hogland et al. (1987);
Young et al. (1996)
NA = Not Applicable or Not Available. Removal efficiencies may be based on either mass balance or average concentration calculations. The values may originate from evaluation of multiple events or from long-term monitoring. Ranges are provided wherever possible.
1 Based on capture of 12.7 mm (0.5 in) of runoff volume. Effectiveness directly related to volume of captured runoff.

Other Management Objectives

Initial screening of the suite of available BMPs can also be performed based on elements that are not related to the performance of the BMP. For example, fiscal management objectives such as providing stormwater management for a specified dollar amount or a percentage of the total project cost can serve as a means to remove high-cost BMPs from further consideration. Table 52 indicates the relative cost for various BMPs, and the BMP Fact Sheets (see Chapter 3) contain additional cost-estimating data that can be used to generate budgetary cost estimates. A final comparative analysis of costs for recommended BMP alternatives is completed in the final selection phase.

Table 52. Relative Rankings of Cost Elements and Effective Life of Structural BMP Options
BMP Capital Costs O&M Costs Effective Life1
Infiltration Trench Moderate to High Moderate 10 - 15 years
Infiltration Bench Moderate Moderate 5 - 10 years before dee tilling required
Bioretention Moderate Low 5 - 20 years2
Detention Ponds Moderate Low 20 - 50 years
Wetlands Moderate to High Moderate 20 - 50 years
Detention Tanks Moderate to High High 50 - 100 years
Underground Sand Filters High High 5 - 20 years
Surface Sand Filters Moderate Moderate 5 - 20 years
Organic Media Filters High High 5 - 20 years
Vegetated Swales Low to Moderate Low 5 - 20 years
Vegetated Filter Strips Low Low 20 - 50 years
Oil-Grit Separators Moderate High 50 - 100 years
Catch Basin Inserts Low Moderate to High 10 - 20 years
Manufactured Systems Moderate Moderate 50 - 100 years
Porous Pavement Low Moderate 15 - 20 years
Adapted from Young et al. (1996); Claytor and Schueler (1996); USEPA (1993); and others
NA = Not Applicable or Not Available
1 Assumes regular maintenance, occasional removal of accumulated materials, and removal of any clogged media.
2 As a relatively new BMP, the effective life is uncertain. It is reasonable to assume an effective life at least as long as a vegetated swale.

6.3.4 Screening Nonstructural BMPs

Nonstructural BMPs provide a flexible method of protecting water quality and improving water resources. Improper handling, use, and disposal of materials in an ultra-urban environment may generate a range of constituents that can contaminate nearby waterways. Contamination of stormwater runoff can often be prevented through the use of nonstructural BMPs, such as covering deicing materials, employee training, and minimizing the use of hazardous products. This is particularly true for a wide range of potentially harmful trace organic constituents that can be prevented from contaminating stormwater through the implementation of nonstructural BMPs. An added benefit to their use is that maintenance requirements for downstream structural BMPs may be reduced.

Nonstructural measures can include activities ranging from pesticide and fertilizer management to chemical storage practices (Young et al., 1996). The nonstructural BMPs that can be applied in both ultra-urban and highway areas can be grouped into six general categories:

  • Litter and debris control.
  • Education and training.
  • Landscaping and vegetated practices.
  • Chemical handling and storage.
  • Containment and diversion.
  • Pesticide and fertilizer management.

The methods or techniques that fall under these categories can be implemented to address constituents at a variety of spatial scales for a specific site or at community or watershed scales. In addition, nonstructural BMPs have little, if any, space requirements, making their use ideal for ultra-urban areas. Screening procedures for nonstructural BMPs require an analysis of specific constituent-generating activities or practices within a drainage area that may contribute constituents to stormwater and an assessment of their ability to qualitatively meet management objectives if controlled.

Analysis of Constituent-Generating Activities

The analysis of constituent-generating activities in a drainage area focuses on the feasibility of practices that avoid the exposure of any potential constituent-generating activity to stormwater. These practices may reduce the need for any structural treatment BMP by altering, enclosing, covering, or segregating the activity. Many industrial facilities include this analysis in their Storm Water Pollution Prevention Plans required for NPDES permits (see Section 3.9, Other Nonstructural BMPs). A flow chart that identifies constituent pathways, and both existing and potential management measures is a useful tool to help identify and assess potential nonstructural BMPs. Each nonstructural BMP, for example, uses a specific constituent removal process or mechanism. For nonstructural BMPs, the processes or mechanisms used to remove constituents include:

  • Prevention (elimination) of an activity (e.g., pesticide use).

  • Change in process to minimize the constituent loss (e.g., optimize salt application).

  • Segregation of the constituent from the stormwater runoff to prevent its loss (e.g., berms to control spills).

  • Education and training about the proper use and disposal of materials (e.g., employee training programs).

Table 53 provides a listing of potential nonstructural BMPs and their associated constituent removal processes.

Table 53. Nonstructural BMPs and Their Constituent Removal Mechanisms
BMP Removal Mechanism Management Objective Addressed1
1 2 3 4 5 6 7
Ultra-Urban Areas
Litter and Debris Control  
Property maintenance Process   ♦◊     ♦◊ ♦◊ ♦◊
Proper dumpster placement Segregation   ♦♦     ♦♦   ♦♦
Parking lot sweeping Process   ♦♦ ♦◊ ♦◊ ♦◊   ♦♦
Frequent storm drain maintenance Process   ♦◊       ♦◊  
Stream cleanups Process ♦◊ ♦◊ ♦◊ ♦♦ ♦◊ ♦◊  
Education and Training  
Storm drain stenciling Education
Prevention
  ♦◊         ♦♦
Employee education Education   ♦◊       ♦◊ ♦♦
Landscaping/Vegetated Practices  
Landscaping/groundskeeping programs Process   ♦♦     ♦◊   ♦◊
Chemical Handling and Storage  
Covered raw material storage Prevention   ♦♦     ♦◊ ♦◊ ♦◊
Hazardous materials handling and disposal Prevention   ♦♦       ♦◊ ♦◊
Spill control plans Process   ♦♦       ♦♦  
Proper hazardous materials and chemical storage Process   ♦♦       ♦♦ ♦◊
Containment and Diversion  
Covered fueling stations Prevention   ♦♦          
Loading dock covers and proper location Prevention   ♦♦          
Elimination of non-stormwater discharges and connections Process   ♦♦       ♦◊  
Highways
Litter and Debris Control  
Road maintenance Process   ♦♦ ♦◊   ♦◊    
Streetsweeping Process   ♦♦ ♦◊ ♦◊ ♦◊    
Adopt-A-Road program Process     ♦◊   ♦◊   ♦♦
Adopt-A-Stream program Process
Education
♦◊ ♦◊ ♦◊ ♦◊ ♦◊ ♦◊ ♦♦
Pesticide/Fertilizer Management  
Pesticide application control Process
Education
  ♦♦       ♦◊ ♦♦
Landscaping/Vegetated Practice  
Mowing reduction Process   ♦◊   ♦♦ ♦◊   ♦♦
Containment and Diversion  
Sediment and erosion control Process ♦◊ ♦♦ ♦♦   ♦◊    
Chemical Handling and Storage  
Road salt application and storage Process   ♦♦     ♦◊ ♦◊ ♦◊
Municipal fleet maintenance Process   ♦♦          
Proper hazardous materials use storage Process   ♦♦       ♦◊ ♦◊
1 (1) Flood protection, (2) Water quality, (3) Stream stability, (4) Recreation, (5) Aesthetics, (6) Public safety, (7) Cost.
♦◊ = Possible, ♦♦ = Likely.

Ability to Meet Management Objectives

Potential nonstructural BMPs are also screened on their ability to achieve management objectives. This can be done on an individual or combined basis. Table 53 illustrates the nonstructural BMPs that have the potential to address the seven management objectives identified previously (see Section 6.3.1).

Management Objectives for Ultra-Urban Areas

Due to chronic flooding and excess constituent loadings from stormwater within a highly urbanized section of the Lake Olive, Florida, drainage basin, the city of Orlando proposed to divert a portion of the stormwater runoff to nearby Lake Lawsona. In addition to this diversion, the city requested that a system be developed and designed that could provide both underground storage and treatment of the stormwater to reduce constituent loads entering Lake Lawsona (Dyer, Riddle, Mills, & Precourt, 1996).

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Questions and feedback should be directed to Susan Jones (Susan.Jones@dot.gov, 202-493-2139) and Marcel Tchaou (Marcel.Tchaou@dot.gov, 202-366-4196).

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