DOT plans to replace guardrails on stretch of road in Keene Valley
By Phil Brown
Motorists should expect slowdowns on Route 73 this summer while work crews replace guardrail on a 15-mile stretch of road.
The work will begin in June and conclude in the fall, according to the state Department of Transportation.
DOT is replacing self-oxidizing guardrails (brown in color) with galvanized steel ones, which are stronger. The state had installed brown ones in the Adirondack Park for aesthetic reasons: they blend in better with the woodsy surroundings.
Numerous guardrails are to be replaced along the highway between Keene Valley and the junction with Route 9 in North Hudson. Generally, the crews will work between 7 a.m. and 5 p.m. Mondays through Thursdays. Motorists should expect lane closures on these days.
Last week, DOT installed steel stakes along Route 73 in Chapel Pond Pass to prevent people from parking along the road near the Roaring Brook Falls trailhead. DOT also blocked two pull-offs where rock climbers used to park to access cliffs in the pass. DOT’s actions, which were not publicized in advance, were roundly criticized in online forums, especially by climbers.
The guardrail crews have put up white survey flags and marked the road in front of Chapel Pond Slab, one of the Park’s most popular climbing venues. Climbers often park on the shoulder there. However, DOT says the project “is not expected to impact any existing parking locations for climbers at the Chapel Pond Slab.”
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It is true that self-oxidizing steel guardrails do not have the same lifespan as do galvanized guardrails. Although the aesthetic of the brown guardrails is in keeping with the Adirondacks woods and color themes, they also offer an advantage in not shedding zinc contamination to nearby waters.
Zinc is often the most prevalent heavy metal contaminant in highway runoff. Being adjacent to relatively pristine waters of Beede and Roaring Brooks flowing to the Ausable and to the North and South Branches of the Boquet flowing in the other direction, I would hope that the decision to use galvanized steel considered the potential impacts on water quality and zinc accumulation in fish in these sensitive waters.
I’ve used the self-oxidizing guardrails along route 73 as an example of a forward thinking means of limiting introduction of zinc into pristine waters in reviews of stormwater runoff analyses of other highway projects. It would be unfortunate if the DOT has decided to replace the self-oxidizing guardrails with galvanized steel guardrails without due consideration of potential adverse impacts associated with zinc as noted.
Thank You Mr. Hart
Hello Thomas Hart,
The amount of zinc used to protect steel structures from corrosion is small compared to the structure itself and the addition of zinc into waterways after storm events or on an average annual basis is even smaller. As the galvanized steel weathers over time, zinc corrosion products (zinc oxide, zinc hydroxide, zinc carbonate) may be added to the existing background level of zinc in the water, but only on a very temporary basis. Even if there are multiple sources of zinc on a river, the dilution factor and suspended solids removal is such the natural background level of zinc is relatively unchanged approximately 2500 feet downstream from each zinc source.
Many case studies have shown, this addition of zinc to the water environment does not cause the background level of zinc to exceed the criterion level defined
by the U.S. Federal Clean Water Act as the amount of zinc in water causing toxicity to aquatic organisms.
The American Galvanizers Association publishes a free white paper containing six case studies and information addressing common misconceptions:
https://galvanizeit.org/education-and-resources/publications/zinc-in-the-water-environment-white-paper
Thank you Alana Fossa for the actual science explaining the real-world impacts of the materials in question as opposed to the previous comment which was simply loaded with potentially fear inducing “sciencey” speak that so many these days fall for.
Relative load levels from metal contaminants in storm water according to the Transportation Research Board’s Bridge Stormwater Runoff and Treatment Report (Taylor et al. 2014) compiled over 11,000 sample results from the Highway Runoff Database and the National Stormwater Quality Database. The data uniformly documents Zinc as the most prevalent contaminant. A value of 0.33 mg/L of Zinc is reported which is much higher than Copper (0.082 mg/L) or Lead (0.062 mg/L). More toxic contaminants like Chromium, Cadmium and Cyanide run at levels at 100th the amount of Zinc.
Contaminant loads in sediment tend to mirror the relative levels found in highway runoff.
Using a lethal level dose as the protective measure is the absolutely wrong metric here. A better metric is whether the the existing water and sediment contaminant level is low in these rivers, and if they are relatively pristine, what the impact of introducing new levels of contaminant may mean. It’s like the commercial asking if you’re ok with your drinking water having a safe level of lead contamination. In these Adirondack rivers, the affect of metals, including zinc, have heightened toxicity based on the relatively high levels of acidified snowpack runoff.
At issue here is whether the effort has been taken by NYS DOT’s environmental section to determine if a linear source of zinc represented by miles of guide rail replacement has an adverse impact on river water quality running adjacent to the highways. I hope that due diligence was done prior to making the decision to move forward.