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Environmental Best Practices
The earlier an opportunity exists in the project delivery process using environmental best practices, the more is benefited. For instance, best practices employed in the planning phase have more potential for environmental benefit than practices included in the design phase, which have more potential benefit than best practices used during construction or those relating specifically to materials. There are several other strategies that are being developed by FLH.
Planning
Transportation planning and use of management strategies.
- Thoughtful planning emphasizes transportation solutions and alternative transportation modes that move people most efficiently with regard to energy consumption and other resources.
- Developing facilities that allow and encourage non-motorized transportation for frequent trips between destinations of short distances (i.e. within the developed facilities of National Parks) reduces energy and air pollution.
- Management Strategies:
- Congestion managed strategies results in fuel savings, less vehicle wear and tear, and less use of alternative, indirect routes.
- Safety managed strategies reduces the damage and replacement of vehicles and parts, and lowers the need for emergency response and resources for victim care.
- Pavement and Bridge managed strategies emphasizes solutions that extend the service life of pavements, roadway materials, bridges, and tunnels resulting in lower need of raw materials and resources for future road reconstruction.
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Design
- Remote sensing technologies such as aerial photography, satellite imagery, and LiDAR reduce the amount of time and ground disturbing activities needed for survey and mapping activities.
- Context sensitive design techniques result in a reduction of the footprint and intrusiveness of our projects, resulting in less environmental impact. Using lesser standards, where appropriate, results in less overall disturbance, excavation, and embankment, and less need for revegetation and erosion control items. Click here for FLH/CSD examples.
- Laying lightly on the land. Through careful design, with attention to techniques for "laying lightly on the land", and for cut and fill minimization during the design process, the area of new disturbances are kept to a minimum, resulting in less vegetation removal and erosion, and less excavation and embankment materials handled and hauled, which results in environmental benefits and substantial energy savings.
- Quality design processes. Use of high-technology interactive highway design software results in evaluation of more alternatives and more detailed evaluation of impacts. State-of-the-art survey and mapping techniques, combined with latest design software, allows higher levels of precision in the design process, and results in a more precise "fit" of the designed facility to the existing environment, with reduced overall disturbances.
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Construction
- Quality construction techniques. Use of appropriate specifications for construction practices results in extended service life and reduced need in the future for rehabilitation of reconstruction of the constructed facility.
- Site-specific revegetation planning, design, and construction using a diverse mix of native species. Utilize available expertise from soil scientists and botanists to select revegetation techniques appropriate to the individual project, and within site-specific locations. Use knowledge and experience of local revegetation experts to incorporate the most successful proven techniques and materials.
- Clean all equipment prior to entering or re-entering construction areas to minimize the spread or introduction of non-native vegetation.
- Recent use of pay factors and measurement of ride quality has resulted in increased pavement smoothness, which results in less fuel consumption for the facility users. Modest improvements in pavement smoothness result in large accumulated savings in fuel consumption over the long run.
- Application of dust palliatives (33.5 KB, PDF*) on graded areas and interim aggregate courses uses less water, resulting in less water treatment required of municipal supply, less pumping and tanker truck hauling, and related impacts.
- Erosion Control:
- Use latest, most effective erosion control devices to reduce impacts to adjacent environment. Use of more efficient erosion control devices (i.e. excelsior logs in lieu of straw bales) results in less quantity of product. Use renewable and biodegradable revegetation and erosion control product materials such as straw, aspen wood fibers, coconut fibers, etc. for erosion control mats and sediment logs.
- Recycling slash for revegetation and erosion control. Chipping and mulching existing vegetation from the clearing for re-use as mulch (in lieu of imported materials). Transplanting existing plants instead of importing container stock. Use of local native materials (i.e. brush barriers, wattles) for erosion control.
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Materials and Pavements
- Conserving and Recycling (Click here for FHWA's official policy on recycling):
- Efficient use of materials conserved from the roadway excavation. Material investigations, evaluation, and designation during the design process allow for efficient use of in-situ materials. Such investigations identify opportunities for conservation and careful use of quality materials selected from the prism excavation for topsoil, subgrade topping, riprap, etc.; and results in more effective revegetation, reduced need for thicker courses of imported aggregate, and surfacing materials, etc. Further evaluation during the actual construction activity, and flexible methods of payment, also allows the construction staff and contractor to make use of these opportunities.
- Pavement Recycling - Existing asphalt pavement and aggregate base materials are pulverized, conserved, and recycled as base materials for new asphalt paving on essentially every Park Road and Parkways surfacing project. This reduces the need for extraction of new aggregate material and the energy required for producing it; thus reducing the fuel and other materials consumed during transportation of surfacing materials imported from distant sources.
- Efficient, quality pavement design and pavement manufacturing processes (Superpave) reduces the overall thickness (quantity) of pavement structural section by improving the strength and stability of asphalt pavement mixtures.
- Use porous asphalt pavement and concrete. These pavements will support traffic and allow turf growth in parking areas, pull-outs, and shoulders.
- Use aggregate-topsoil with turf instead of paved shoulders.
- Re-using "bag house fines". Capturing these particulates at the batch plant reduces air pollution, and re-introduction of the fines in the asphalt mixture makes use of an otherwise waste byproduct.
- Revised aggregate gradation bands. Our newest specifications (FP-96 English (2,686 KB, PDF*) or Metric) typically allow for use of local State specifications for gradation of asphalt mixtures, which reduces the amount of re-processing and additional crushing and handling of aggregate materials. This also reduces the need to mobilize additional crusher plants, solely for our projects.
- Use of "high range" retardants in concrete mixtures has resulted in reducing the need to establish temporary batch plants close to the project site. Instead, existing commercial concrete batch plants can be used, which reduces the impacts of setting up a temporary plant within a more sensitive environmental setting. The haul of aggregate and cement is typically the same in either case.
- Use of alternatives to cutback asphalts for prime coats. The cutback asphalts contain high volatile organic compounds (VOC's), which contribute to air pollution. In certain metropolitan areas these asphalts are not allowed, and are not being used in rural areas anymore.
- Elimination of hazardous solvents. We no longer use TCA, TCE, Methylene Chloride solvents for asphalt mix tests. Instead, we are using biodegradable solvents for asphalt testing.
- Use of Sulphur as an asphalt additive and extender. Our most recent project at Lake Meade NRA allowed the use of Sulphur in polymer-sulphur modified asphalt, which reduces the amount of required liquid asphalt, making use of an otherwise waste product.
- Use of blended hydraulic cements. An example is a recent project in Zion NP which specifications allowed the use of fly ash, blast furnace slag etc. to be added to the cement, which is an effective use of an otherwise waste byproduct.
- Use of wood guardrail posts in lieu of steel utilizes a renewable resource in lieu of permanent extraction of ore.
- Retaining wall materials. Simulated stone results in more efficient use of local commercial materials and reduces need for quarrying natural stone materials and associated transportation costs from distant sources or more sensitive areas.
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Operations
- Alternative Fuels - Propane is being used for bus transit vehicles in Zion NP, resulting in less air pollution.
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Other Suggested Strategies
- A technology deployment initiative is underway to evaluate the effects of more efficient use of asphalt materials, such as eliminating prime coats and percentages of asphalt in mix designs.
- Salvaging and scrapping for re-processing existing metal culverts, signs, guardrails, retaining wall materials, etc. that are otherwise hauled to landfill sites.
- Use recycled plastic material for traffic control devices (drums, cones, etc.) and for drainage features (culvert pipes, underdrains, and geocomposite sheet drains).
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