TRANSPORTATION - BTS - Bureau of Transportation Statistics

landfills, or it can be dumped in certain disposal sites in open waters. Contaminated material,on the other hand, may have to be treated to reduce its toxicity and managed usingunique methods, increasing the costs of navigational dredging. Contaminants include heavymetals and other pollutants, such as dioxins and polychlorinated biphenyl (PCBs), that havebeen discharged into water and air. Contributing sources are industrial facilities within portsand upstream and nonpoint sources, such as transportation and agriculture. Contaminantsreduce or injure fish and wildlife populations. Improper disposal of contaminated materialcan present costly environmental and human health risks.Keys to the FutureContinued vigilance will be vital to reducing and reusing the many and varied types of solidwaste generated by the transportation sector. Pressure to reduce and reuse solid waste willemanate from landfill capacity problems and NIMBY (“not in my back yard”) sentiments, butalso will be spurred on by technological innovations that reduce the amount of waste producedand which make recycling solid waste easier and more cost effective.Land-Use and Habitat Effects of TransportationThe effects of transportation on land use and habitat include the impact of transportation onwetlands, the introduction of invasive species into ecosystems by transportation, and transportationand land-use interactions.Wetlands: Since the early 1800s, the United States has lost or converted more than half of thewetlands that existed prior to European settlement. About 100 million acres of wetlandsremain in the contiguous 48 states. Some states, such as California, Indiana, and Iowa, havelost more than 90 percent of their original wetlands. Much of this loss resulted from agriculture,urbanization, and infrastructure construction. In the 1960s and early 1970s, wetlandloss was estimated at approximately 450,000 acres per year, primarily due to agriculturalactivities [USEPA 1996]. According to the U.S. Department of Agriculture resource inventories,the wetlands’ rate of loss has, subsequently, declined to approximately 100,000 acres per year,not including those created or preserved through wetland restoration activities and programs,and now amounts to less than 50,000 acres per year. ISTEA and TEA-21 provided expandedfunding for wetlands banking, which allows the mitigation of several or many projects at onelocation by combining funds to establish and manage larger wetlands complexes. Thisenhances wetlands functions and improves management while controlling costs.Data on annual wetlands losses due to alltransportation projects are not available, butthose caused by federally funded highwayconstruction have been available since 1996.Between 1,100 and 2,400 acres have beenconverted or lost annually since then (table 5-7).This represents less than 10 percent of theestimated total national loss or conversion andhas been compensated at a rate of about 2.3 to 1,exceeding USDOT’s performance standard of 1.5to 1 [USDOT 1999]. In other words, wetlands arebeing replaced at more than twice the rate of lossin the federal-aid highway program.Table 5-7Wetlands Loss and Replacement forFederal-Aid Highways: 1996-991996199719981999Acresimpacted1,5681,6991,1672,354Acresreplaced3,5544,4842,5575,409Recoveryratio2.3:12.6:12.2:12.3:1Target1.0:11.0:11.5:11.5:1Source: U.S. Department of Transportation, Federal HighwayAdministration, Connecting America: 1999 Report to theNation, available at http://www.fhwa.dot.gov/reports/1999annual/, as of Sept. 25, 2000.5-46