G Michael Fitch

Environmental Life-Cycle Assessment of Winter Maintenance Treatments for Roadways

Departments of Transportation (DOTs) rely heavily on chloride-based treatments for winter road maintenance despite the well- documented effects of these chemicals on infrastructure and the environment. Proposed alternative treatments have yet to be widely adopted because of economic and technical limitations that are largely outside of the control of the DOT. This work explores the application of winter maintenance chemicals with a life-cycle approach to understand which actions a DOT can take to reduce the negative life-cycle environmental impacts of these activities. Three representative treatments and/or best management practices are compared: conventional rock salt, calcium magnesium acetate (CMA), and preemptive treatments of roadways with a brine of salt and/or CMA. The results conclusively show that CMA, which has been widely touted as an environmentally preferable, if more expensive, alternative to chloride-based treatments, has considerably higher environmental impacts over its entire life cycle. Most of these burdens are associated with the upstream production processes required to generate the CMA. The salt-based treatments consume considerably less water, energy, and generate fewer greenhouse gases and biochemical oxygen demand in receiving waters. Applying the chloride chemicals as a brine rather than in the dry form results in important reductions in all environmental impacts over the entire life cycle. This result is consistent for a variety of climate conditions (e.g., representative of coastal, piedmont, and mountain climates) considered for this study, which used historical weather data from Virginia. Because DOTs can affect appreciable improvements in efficiency by using brines, sensitivity analysis identifies the activities specifically resulting in the most important environmental improvement on a systems basis. The DOT-controlled steps with the greatest potential for improvement include reducing the energy consumed for the salt application process and implementing practices that reduce total storm water runoff to reduce chloride loading. DOI: 10.1061/(ASCE)TE.1943-5436.0000453.

Recycling of Salt-Contaminated Storm Water Runoff for Brine Production at Virginia Department of Transportation Road-Salt Storage Facilities

A large part of the Virginia Department of Transportations (DOT) maintenance effort comprises the implementation of its anti-icing program. Earlier research confirmed that Virginia DOT captures a large volume of salt-laden storm water runoff at its 300-plus salt storage facilities throughout the state and that disposal options for this water are limited and costly. Although Virginia DOT is implementing recommended management options to reduce the quantity of salt water captured, this research was undertaken to determine the possibility of recycling salt-contaminated storm water runoff for brine production. Laboratory and field tests were conducted using bench-scale brine generation equipment. In the laboratory phase, brine was produced by using tap water, applying different hydraulic retention times and temperatures. Storm water runoff from a storage pond without any previous treatment was used in the field phase. Results show that the optimum conditions for brine production are low hydraulic retention time (high flow rates) and high temperatures. The total suspended solids present in the storm water runoff did not diminish the quality of brine in the field tests. Economic and environmental benefits can be obtained by applying this recycling strategy.

Impact of Vegetation Management on Vegetated Roadsides and Their Performance as a Low-Impact Development Practice for Linear Transportation Infrastructure

Water quality improvement, constituent mass transport mitigation, and the hydraulic performance of vegetated roadsides were evaluated over 16 storm events for two vegetated roadside strips along Lorton Road in Fairfax County, Virginia. Automated, flow-weighted sampling practices were employed to develop composite samples and event mean concentrations representative of an entire storm event. Lorton Road and two vegetated roadside strips were monitored for flow rate and flow volume to determine hydraulic performance. Collected samples were analyzed for 13 water quality constituents: total suspended solids, total nitrogen, nitrates, phosphate, oil and grease, chemical oxygen demand, total coliform bacteria, Escherichia coli, cadmium, chromium, copper, lead, and zinc. Varying vegetation management practices were employed at each vegetated strip to determine the impact of vegetation management on vegetated roadside performance. The managed and unmanaged vegetated strips achieved a mean peak flow reduction of 76.3% and 89.5%, respectively, while achieving a mean total flow reduction of 80.7% and 87.3%, respectively. The relatively high degree of stormwater infiltration and reduced flow velocity allowed for moderate to high mass loading mitigation for each of the 13 water quality constituents monitored. A sign test analysis of the constituent mass load data revealed that the effluents of both vegetated strips were statistically lower than those of the Lorton Road runoff for all 13 constituents and both hydraulic parameters. The unmanaged vegetated strip effluent had statistically lower peak flows and mass loads of total nitrogen, phosphate, copper, and zinc compared with those of the managed vegetated strip.

Nonpublic Funding Options Available to Virginia Department of Transportation for Interstate Safety Rest Areas

In 2009, 19 Virginia Interstate safety rest areas (SRAs) were closed for a savings of approximately

Characterization and Environmental Management of Storm Water Runoff from Road Salt Storage Facilities

9 million per year for the Virginia Department of Transportation. These closures were opposed by those concerned with the possible effects on traveler safety, tourism dollars, and the commonwealths business reputation. Virginias SRAs were reopened in the spring of 2010, but not before the Virginia General Assembly passed House Joint Resolution 126 and Senate Joint Resolution 99 in early 2010 to investigate new and feasible nonpublic funding options for the continued operation of Virginias SRAs. Federal law (Title 23, U.S. Code, Section 111: agreements relating to use of and access to rights-of-way on the Interstate system) prohibits federal-aid highways from offering any type of commerce for “serving motor vehicle users” at SRAs located on the Interstate Highway System right-of-way unless the establishment was in existence before 1960 and is owned by a state. Accordingly, commercial enterprises in Virginia and elsewhere are located at Interstate interchanges, and changes to the aforementioned federal code are consistently opposed. The nonpublic funding options presented were identified through a review of state and federal law, surveys of Virginia rest area users, interviews with industry groups, an assessment of initiatives by state departments of transportation for Interstate SRA funding, and questionnaires distributed to these state agencies. In the short term, simple options include the expansion of vending items, indoor advertising, and facility sponsorship. Complex options include relocating facilities under regional management and commercial facilities outside the Interstate right-of-way. In the long term, modification of the provisions of Title 23, U.S. Code, Section 111, or the repeal of Title 23, U.S. Code, Section 301: Freedom from tolls, would allow states additional nonpublic funding for Interstate SRAs.