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Kingston Ash Slide

Ecological Investigations

Last Updated November 14, 2011


After dredging more than 3.5 million cubic yards of ash from the Emory River, TVA estimates that there could be 250,000 to 400,000 cubic yards of residual ash still in the river system.  TVA is conducting several types of investigations to evaluate the potential ecological effects of that ash. Study results will help determine how to address the residual ash.

The CERCLA non-time-critical process requires that different alternatives be evaluated and compared in a river Engineering Evaluation/Cost Analysis (EE/CA).  Alternatives have not yet been developed for the river EE/CA, but may include removing some or most of the remaining ash, leaving it in the river for natural processes to alleviate ecological effects, capping the ash in place, or any combination of these three actions.  However, in order to develop and compare the alternatives, more information is needed.

TVA designed a monitoring program to study effects on local wildlife and the ecosystem.  In addition, an integrated research team consisting of TVA scientists and independent, nationally-recognized Federal research institutes and universities is assessing potential effects on wildlife.

Ecological investigations will address specific research questions, as stated in the monitoring plan:

  • Will further ash removal release hazardous legacy materials that were present in the river bottom prior to the ash spill?
  • Will further ash removal disturb the habitat of bottom-dwelling organisms that have returned to the area since the completion of dredging?
  • Will storm flows move remaining ash downstream?
  • To what extent is residual ash mixing with or being covered by natural river sediments?
  • Are ash constituents in chemical forms that can be absorbed by plants, animals, insects, etc?
  • Are chemical changes occurring to ash constituents that may change their potential biological impacts?
  • How significant is the potential for adverse ecological effects?


Ecosystem Monitoring

An ecosystem is a community of organisms and its environment functioning as a whole.  At the Kingston Recovery Project, TVA is monitoring the ecosystem on a sub-organism, individual, population and community level to determine if any adverse effects have occurred because of the spill.


Monitoring Objectives


  • Measure metal concentrations in fish reproductive organs and other tissues
  • Evaluate ovaries of fish for reproductive condition
  • Measure components in blood that indicate whether fish kidneys and gills are functioning well
  • Relate effects seen at the sub-organism level to potential effects on individual organisms


  • Measure metal concentrations in whole fish/fish fillets and eggs from tree swallow, great blue heron, Canada goose, osprey, turtles, and frogs, and compare each with values published in scientific literature that have been associated with adverse effects on organisms
  • Evaluate anomalies (disease incidence, skeletal deformities, etc.)  in individuals as compared to pre-spill results
  • Measure feathers and tarsus (lower leg) length of tree swallow nestlings to determine whether sub-lethal effects are occurring
  • Relate effects seen at the organism level to potential population effects


  • Evaluate clutch size (number of eggs produced at a single time), hatching and fledgling success (success leaving the nest for the first time) in tree swallows and turtles
  • Measure reproductive success of fish exposed to ash in the laboratory
  • Measure changes in sport fish population size distributions that might indicate lower survival or spawning success as a result of the ash spill
  • Relate effects seen at the population level to potential community dynamics


  • Measure the fish and benthic macroinvertebrate (invertebrates large enough to be seen without a microscope) community richness and density
  • Evaluate the health of the fish and benthic macroinvertebrate communities
  • Relate effects in one community to those seen throughout the river system



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