3.2A – Construction – Structural and Permanent
Measuring design feature performance
- After construction has been completed and the site is permanently stabilized, reduce the average annual total suspended solids (TSS) loadings by 80 percent (for the purposes of this measure, an 80 percent TSS reduction is to be determined on an average annual basis); or reduce the post-development loadings of TSS so that the average annual TSS loadings are no greater than pre-development loadings.
- To the extent practicable, maintain post-development peak runoff rate and average volume at levels that are similar to pre-development levels.
Incorporate pollution prevention procedures into the operation and maintenance of roads, highways, and bridges to reduce pollutant loadings to surface waters.
Measuring design feature performance
In urban areas that do not meet the criteria to be covered under the NPDES storm water regulation, the NPS program requires that owners of new developments implement management practices to meet the requirements of the management measure described above. There are two parts to the requirement: first, runoff quality must be addressed by implementing treatment controls that remove at least 80 percent of the average annual TSS loadings in runoff. TSS is used as a measure of pollutant removal effectiveness because it is a common pollutant in urban runoff and is often associated with other pollutants such as nutrients and heavy metals. The second part of the management measure directs developers to implement practices to control the timing and volume of runoff leaving the site such that it mimics the hydrology of the site before development. The adverse impacts of increased hydraulic loadings to urban streams are well documented and include channel widening, aquatic and riparian habitat loss, increased pollutant loads, temperature impacts, and increased erosion of stream banks and streambeds, to name a few.
The NPS management measures do not specify a single method that should be used to achieve this level of pollutant removal, which allows developers flexibility in meeting both the 80 percent TSS removal and pre-development hydrology criteria. The types of technologies that can be used to achieve both criteria include detention ponds/vaults, retention ponds and wetlands, infiltration practices, filtration practices, open channel practices, and various proprietary practices, as described in the following:
Detention Ponds and Large-Scale Structural Controls:
- Temporary detention ponds or vaults that hold runoff and release it slowly but completely after a 72-hour or shorter period.
- Retention pond or wetlands in which a permanent pool of water is maintained and runoff is slowly released over time. Retention practices, by allowing water to stand for a longer period of time, achieve greater pollutant removal through settling and allow for biological uptake using wetland vegetation.
- Open channel practices, such as grassed swales, are commonly and effectively used to collect, convey, and infiltrate runoff, but they are not intended to drain large areas of impervious surfaces and therefore are typically implemented in combination with other practices.
Devices that fit into the storm water conveyance system:
- Infiltration practices, such as basins, trenches, and French drains that collect runoff and convey it through a porous matrix such as sand or organic filters and bioretention practices.
- Trash racks.
- Proprietary practices that are typically installed underground use mechanisms such as settling, absorption, and micro filtration as well as other mechanisms such as centrifugal force and gross filtration to remove solids and floatable debris.
Pollution prevention for the operation and maintenance of roads, highways, and bridges.
- Potholes and cracks in road surfaces and retaining walls should be repaired promptly to prevent further degradation of the road surface. When these activities, along with road expansion and repaving, disturb vegetated areas, the exposed soils should be protected from erosion using erosion and sediment controls (see Management Measure 1A) and denuded areas should be renegotiated using seed, mulch, or sod immediately after road work has been completed.
- When performing bridge maintenance activities, use enclosures, and containment and collection systems to collect pollutants. Recommended enclosures include free hanging enclosures, total structure enclosures, and negative pressure systems, and recommended containment and collection systems include: cofferdams, barges, containment booms, and vacuum sanders. A runoff control plan should be in place for each large project, and smaller projects should be governed by standard operating procedures to prevent contamination of storm flows and to control spills.
- Chemicals and abrasives used to prevent ice on road surfaces in winter should be stored on an impervious pad and covered to prevent runoff from carrying away any of the materials. Not only does this prevent runoff pollution, but it also preserves the materials for their intended use. Stockpiled deicing materials should not be stored in floodplains.
- Deicing materials should be selected and applied to cause minimal harm to the environment. Where areas might be sensitive to Salinization, alternatives to road salt, such as sand or any number of organic products that are currently on the market, can be used. Organic products should be avoided in areas that have low biochemical oxygen demand. Sand should not be used in areas with sediment problems such as excessive streambank scour or embedded gravels.
- When applying materials, care should be taken to apply only the amount of material that is required to provide a safe road surface. Local studies can be undertaken to determine the appropriate amount of deicing materials to be used for different road surfaces in different conditions and locations.
- Snow that is plowed from road surfaces should never be stockpiled on or near frozen surface waters or retention ponds. Once the snow and ice has melted, road surfaces should be swept or vacuumed to remove and reclaim sand, salt, or other deicing chemicals. This material can be recycled or disposed of in a locally approved manner.
Trash and Debris Removal
- Streets and parking lots should be periodically swept or vacuumed to remove trash and debris. The frequency with which each area or road is swept should depend on the quantity of trash that is seen over time. Areas that are heavily traveled or tend to attract litter should be swept more frequently. Also, areas that drain to sensitive receiving waters or areas that have known trash and debris problems should be swept more frequently.
- Anti-litter signage should be posted throughout the community, especially in places with known trash/debris problems. Litter and dumping laws should be strictly enforced, and the municipality should provide a hotline or other medium for citizens to report littering or dumping (see Management Measure 3.3, education and outreach).
- Bay Area Stormwater Management Agencies Association (BASMAA), New Development Program.
- California Department of Pesticide Regulation’s (DPR) Surface Water Protection Program protects human health and the environment by preventing pesticides from adversely affecting surface waters, by addressing both agricultural and nonagricultural sources of pesticide residues in surface waters. It has preventive and response components that reduce the presence of pesticides in surface waters.
- California Department of Transportation (Caltrans) Adopt-A-Highway Program provides an avenue for individuals, organizations, or businesses to help maintain sections of roadside within California’s State Highway System.
- California Department of Transportation, Division of Maintenance, Roadside Maintenance Program is responsible for vegetative control and the Adopt-a-Highway Program.
- California Department of Transportation, Division of Maintenance, Roadway Maintenance Program manages rehabilitation and maintenance of pavement and snow and ice control.
- California Coastal Commission, CCC Model Urban Runoff Program (MURP) is a "how-to" guide for addressing polluted urban runoff in small municipalities (with populations under 100,000) in California.
- Green Highway Partnership (GHP) is a voluntary, public/private initiative that is revolutionizing our nation's transportation infrastructure. Through concepts such as integrated planning, regulatory flexibility, and market-based rewards, GHP seeks to incorporate environmental streamlining and stewardship into all aspects of the highway lifecycle.
- SWRCB Storm Water Program, most urban runoff is regulated under the NPDES permitting program as point source discharges from municipally owned or operated separate storm sewer systems (MS4s). This program has requirements distinct from those of the NPS program, although the same set of management practices is appropriate for controlling pollutants from both storm water and nonpoint sources. The specific requirements for owners and operators of MS4s depend on the municipality’s or public entity’s population size and water quality concerns.
- USEPA and the National Sanitation Foundation, Environmental Technology Verification (ETV) develops testing protocols and verifies the performance of innovative technologies for environmental controls, including storm water treatment practices. It is a good source for determining the relative performance of new proprietary technologies.
- International Stormwater BMP Database provides access to information on BMP performance for studies conducted over the past 15 years. Users can search these data to assess the appropriateness for use of management practices under various conditions.
- Pacific Northwest Snowfighters Association provides resources on deicing and anti-icing products and practices.
- Bay Area Stormwater Management Agencies Association (BASMAA), Start at the Source: Design Guidance Manual for Stormwater Quality Protection this guidance manual is designed for planners and resource managers, and focuses on the importance of considering storm water quality in the early stages of planning and designing new land development projects. This manual reviews storm water management practices and provides technical information and case studies related to management practice implementation.
- California Department of Transportation (Caltrans), Statewide Storm Water Quality Practice Guidelines, section 5 of this manual describes treatment practices that Caltrans has approved (biofiltration swales and strips, infiltration basins, detention devices, traction sand traps, dry weather flow diversion, and linear radial device and inclined screens) and the process by which the practices are selected, sited, sized, designed, and implemented to minimize environmental impact.
- California Department of Transportation (Caltrans), Statewide Storm Water Management Program prevents the adverse effects of storm water runoff from Caltrans roadways and facilities. This program provides a comprehensive effort to preserve and improve water quality in California.
- California Department of Transportation, Guidance Manual: Stormwater Monitoring Protocols, Second Edition covers the entire process of storm water monitoring, with sections that describe the following topics: purpose and objectives; site, constituent, and monitoring method and equipment selection; sampling and analysis plan development; installation and maintenance of equipment; training; logistics; sample collection; quality assurance/quality control (QA/QC); preparation of laboratory samples and analytical methods, QA/QC data evaluation, and data reporting protocols.
- California Environmental Resources Evaluation System (CERES), California Watershed Portal provides the information and tools to support local watershed planning, restoration, monitoring, and education. CERES and WITS are programs of the California Resources Agency.
- Caltrans, BMP Retrofit Pilot Studies for modifying existing infrastructure such as facilities and highways to address water quality. A number of different management practices are being studied, including biofiltration, infiltration basins and trenches, catch basin inserts, detention basins, and media filters.
- Center for Watershed Protection Snow, Road Salt and the Chesapeake Bay examines what happens to the salts and other chemicals applied to the roads in the winter and what is known about their impact on the environment. The paper addresses the environmental impacts of salt and includes ways to reduce the use of salt.
- City of Los Angeles, Stormwater Program has two major elements – Pollution Abatement and Flood Control. Pollution Abatement involves compliance with federal regulations, and in essence, constitutes the model program components (i.e., Public Education, Inspection/Enforcement, Illicit Discharges/Illicit Connections, Program Compliance) while Flood Control is essential for the protection of life and property.
- Computational Hydraulics International, PCSWMM, this tool is a graphical decision support system used for EPA’s SWMM program to better facilitate storm water management modeling. This program helps simplify the complexities of large and small storm water modeling projects and is ideal for solving problems ranging from BMP installations to continuous hydrology. The application can be purchased at the site, and technical support is also available.
- Contra Costa County, Clean Water Program, Start at the Source Design Guidance Manual for Stormwater Quality Protection and other resources, guidebooks and reference documents written by or supported by the Clean Water Program.
- Delaware Department of Natural Resources and Environmental Control Green Technology: The Delaware Urban Runoff Management Approach is a technical manual that reviews impacts of urban runoff on stream ecosystems and riparian zones. The manual presents how green technology management practices can effectively address these impacts and how to properly design the most appropriate management practice. The document includes chapters on construction and testing specifications, design standards and specifications, landscaping standards and specifications, summaries of standards for management practices, and a set of typical details for each type of management practice.
- Federal Highway Administration, Manual of Practices for an Effective Anti-Icing Program: A Guide for Highway Winter Maintenance Personnel was written to guide maintenance managers in developing a systematic and efficient practice for maintaining roads in the best conditions possible during a winter storm. It describes the significant factors that should be understood and must be addressed in an anti-icing program, with the recognition that the development of the program must be based on the specific needs of the site or region within its reach. It focuses on the weather information, materials, and methods that will best address site conditions such as level of service, highway agency resources, climatological conditions, and traffic.
- NOAA, Alternatives for Coastal Development, One Site, Three Scenarios illustrates three different development scenarios created for a residential area in coastal Georgia. The analysis calculates and compares economic, environmental, and social indicators. Environmental factors considered in the analysis include vegetated buffers, impervious surface, and pollutant runoff.
- Pitt et al. 2004. National Stormwater Quality Database (NSQD, version 1.1), this research paper presents preliminary findings of a USEPA-sponsored project to assemble and analyze monitoring data collected over nearly a ten-year period from more than 200 municipalities throughout the country. In addition to the analysis, the project will provide recommendations for improving future NPDES monitoring efforts. Some of the issues that are being examined with these data include the occurrence and magnitude of first-flushes, the effects of different sampling methods on stormwater quality data, trends in stormwater quality over time, the effects of infrequent wrong data in large databases, appropriate methods to handle values that are below detection limits, and the necessary sampling effort needed to characterize stormwater quality. Related articles are also available at this site.
- Residential Streets, prepared by the American Society of Civil Engineers, the National Association of Home Builders, and the Urban Land Institute, discusses design considerations for residential streets based on their function and their place in the neighborhood. The publication presents guidance on street widths, speeds, pavement types, streetscapes, rights-of-way, intersections, and drainage systems. It can be ordered online at amazon.com or other online booksellers.
- San Diego County, Project Clean Water is a watershed-based approach to integrating regional efforts at improving water quality. The project includes the development of technical guidance for watershed-based urban runoff programs, education and outreach, and the development of a repository for water quality information in the region.
- San Diego County, Project Clean Water, Existing Residential Areas Model Program Guidance outlines a number of management practices appropriate for existing residential development, as well as an implementation strategy.
- SWRCB, Model Urban Runoff Program was developed by the City of Monterey, in conjunction with the City of Santa Cruz, Monterey Bay National Marine Sanctuary, California Coastal Commission, Association of Monterey Bay Area Governments (AMBAG), and Woodward-Clyde Consultants. The program provides guidance to small municipalities that need to meet NPDES Phase II requirements.
- U.S. Department of Transportation, Federal Highway Administration, Stormwater Best Management Practices in an Ultra-Urban Setting: Selection and Monitoring this manual provides guidance on storm water management in developed urban areas that have limited space for treatment practices. The intent is to promote technology that is cost-effective and low-maintenance for the ultra-urban environment.
- USEPA, National Menu of Best Management Practices for Storm Water Phase II, Post-Construction Storm Water Management in New Development and Redevelopment Fact Sheets guidance for small NPDES-regulated municipalities details several site design practices to reduce the amount of storm water generated on a development site and to disconnect impervious surfaces from the municipal separate storm sewer system. Especially useful for this management measure are the fact sheets listed under "On-lot Treatment" and "Better Site Design."
- USEPA, National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas, in Chapter 5 of this manual describes the different types of treatment controls, including design and maintenance considerations, cost, and effectiveness.
- Washington Department of Transportation, Roadside Manual this manual is to provide guidance on roadside maintenance, including planning, design, construction, and maintenance. The manual has information on sustainable roadsides, environmental functions, wetlands, water quality, parking area design, erosion control, contour grading, soil bioengineering, and vegetative restoration concepts.
Maxted, J.R., and Scoggins, M. 2004: The ecological response of small streams to stormwater and stormwater controls in Austin, Texas USA. Prepared by the Watershed Management Institute for the United States Environmental Protection Agency, Office of Water, Office of Science and Technology, Washington DC; Cooperative Agreement 9701)
Metropolitan Washington Council of Governments. 1987. Controlling Urban Runoff: A Practical Manual for Planning and Designing Urban BMPs. Metropolitan Washington Council of Governments, Washington, DC.
National Research Council, Transportation Research Board. 2000. Primer: Study of the Environmental Impact of Construction and Repair Materials on Surface and Ground Waters. National Academy Press, Washington, DC.
San Francisco RWQCB. 1998. Erosion and Sediment Control Field Manual. San Francisco Regional Water Quality Control Board, San Francisco, CA.
Sansalone, J.J., and S.G. Buchberger. 1997. Partitioning and First Flush of Metals in Urban Roadway Storm Water. Journal of Environmental Engineering 123(2): 134–143.
USEPA. 2005. National Management Measures to Control Nonpoint Source Pollution from Urban Areas. EPA 841-B-05-004. U.S. Environmental Protection Agency, Washington, DC. Downloaded on March 3, 2008.
California Department of Transportation. 1998. Maintenance Manual: Volume 1. California Department of Transportation, Sacramento, CA.