Les efforts pour enlever les sédiments contaminés dans une section de la rivière Saranac près de Plattsburgh va commencer ce printemps. On prévoit enlever 39,200 tonnes cubes de sédiments et de rive contaminée avec du goudron de houille venant de l'usine de gaz de houille qui occupait l'adresse de Saranac Street pendant des décennies. Pendant plus de 60 ans, un volume considérable de goudron de houille a pénétré le sol sablonneux et s'est fait un chemin vers la rivière Saranac.
Les ingénieurs ont passé les quelques dernières années à nettoyer le sol contaminé de la propriété à côté du site: les plaintes d'odeurs et des craintes pour la santé ont changé les habitudes de certains voisins, mais le travail terminé l'automne passé aura enlevé 151,970 tonnes de sols contaminés par le goudron qui se serait retrouvé éventuellement dans la rivière Saranac et le lac Champlain.
Le prochain projet de nettoyer la rivière devrait durer 3 ans, et se limitera entre les mois de mai et septembre pour réduire l'impact sur les populations de poissons durant le printemps et l'automne. Durant l'été, un passage à poissons sera construit. Le creusage de sédiments du fond de la rivière se fera à sec entre deux barrrages qui couperont la circulation de l'eau pour éviter le lessivage des sédiments en aval. Un canal temporaire continuera d'alimenter le lac en eau et l'aspect de la rivière devra être restaurer à la fin de la saison. Le canal temporaire sera navigable, mais un sentier de portage sera aménagé pour les amateurs de canot et de kayac.
Plusieurs stations de prélèvement de spécimens d'air seront installés pour connaître la qualité de l'air dans la région, où se trouvent une école et un terrain de soccer. Les sédiments contaminés enlevés du fond de la rivière seront asséchés sur place pour être ensuite envoyé à un site d'enfouissement approuvé pour les produits toxiques. Les travailleurs essayeront de redonner à la rivière nettoyée un aspect naturel en aménageant des fosses à poissons et des grosses roches où les poissons peuvent s'abriter. Des photos digitales seront archivées avant le début des travaux afin d'aider les travailleurs à remettre la rivière dans son aspect original à la fin des travaux.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"Saranac River cleanup to begin this spring
PLATTSBURGH — Efforts to remove contaminated sediment along a section of the Saranac River near downtown Plattsburgh will begin this spring. The Department of Environmental Conservation is overseeing plans to remove an estimated 39,200 cubic tons of sediments and riverbank contaminated with coal tar from a manufactured-gas plant that operated for decades at the Saranac Street location.
“A considerable volume of coal tar leaked into the sandy soil and eventually found its way into the Saranac River over a 60-year period,” DEC Project Manager Lech Dolata said during a public hearing at Stafford Middle School. “We’ve looked at several plans and have come up with an option we feel benefits everyone — the fish, the residents, the school.”
Engineers have spent the past few years cleaning contaminated soil from the property adjacent to the work site and had to occasionally adjust activities when concerns of foul odors or other health issues arose from area residents or nearby Stafford Middle School. That project, which ended last fall, helped remove 151,970 tons of tar-contaminated soils, materials that would have eventually made their way into the Saranac and Lake Champlain.
The upcoming river phase of the project is expected to take three years, with activities in the river itself limited to May through September to reduce the project’s impact on the spring and fall spawning runs for the fish populations. “Our design provides for a fish passage (during those months of activity),” Dolata said. “The option we’ve selected requires excavation under dry conditions to prevent the re-distribution of contaminants down river.”That means workers will place dams above and below the work site to stop the river flow while contaminated sediment between the dams is removed.
A temporary canal will be built around the work site to provide a continued flow of river water to the lake, but the project requires that workers return the river to its original condition before work ends for the season. Warning signs will be placed above and below the temporary dams. A portage will be installed for canoeists and kayakers moving up and down the river, though Dolata said the temporary passage should be navigable as well.
Air quality will be monitored throughout the work seasons, with a minimum of six monitoring stations located around the site. Two monitors will also be in place at Stafford Middle School: one at the school’s main air intake and a second at the soccer field. Those stations will monitor both dust particles and vapor levels in the air. The school’s air system also has 54 carbon air filters capable of filtering out volatile substances. Excavated sediment will be treated on site to remove water, and the dry sediment will then be shipped off site to a licensed hazardous-waste landfill.
Workers will attempt to restore the river to its original state, including the replacement of large boulders and deep pools that give fish resting and hiding spots. Digital mapping of the river bottom before work will give workers a snapshot to help return the river to its natural setting, Dolata said. Also, surveys will continue on the Saranac River below the work site to determine how much coal tar has made its way downstream and what kind of remedies may be needed for those portions of the lake.
Gas was manufactured at the Saranac Street site from 1896 to 1944 by the Plattsburgh Light, Heat and Power Co. and from 1944 to 1960 by New York State Gas and Electric. Gas produced from the plant was used for lighting, cooking, heating and other purposes. NYSEG has been investigating and working on correcting the site since 1976 and signed an agreement with DEC in 1994 to remove the contamination. NYSEG is not required to release figures on the overall cost of the project, Dolata said, but he estimated the cost for Phase 2 at between $13 million and $20 million."
Excerpts from article written by Jeff Meyers for pressrepublican.com here: http://www.pressrepublican.com/evening/local_story_050160048.html?start:int=30
No comments:
Post a Comment