Modeling Possible Cooling-Water Intake System Impacts on Ohio River Fish Populations

Abstract

To assess the possible impacts caused by cooling-water intake system entrainment and impingement losses, populations of six target fish species near power plants on the Ohio River were modeled. A Leslie matrix model was constructed to allow an evaluation of bluegill, freshwater drum, emerald shiner, gizzard shad, sauger, and white bass populations within five river pools. Site-specific information on fish abundance and length-frequency distribution was obtained from long-term Ohio River Ecological Research Program and Ohio River Sanitation Commission (ORSANCO) electrofishing monitoring programs. Entrainment and impingement data were obtained from 316(b) demonstrations previously completed at eight Ohio River power plants. The model was first run under a scenario representative of current conditions, which included fish losses due to entrainment and impingement. The model was then rerun with these losses added back into the populations, representative of what would happen if all entrainment and impingement losses were eliminated. The model was run to represent a 50-year time period, which is a typical life span for an Ohio River coal-fired power plant. Percent changes between populations modeled with and without entrainment and impingement losses in each pool were compared to the mean interannual coefficient of variation (CV), a measure of normal fish population variability. In 6 of the 22 scenarios of fish species and river pools that were evaluated (6 species × 5 river pools, minus 8 species/river pool combinations that could not be evaluated due to insufficient fish data), the projected fish population change was greater than the expected variability of the existing fish population, indicating a possible adverse environmental impact. Given the number of other variables affecting fish populations and the conservative modeling approach, which assumed 100% mortality for all entrained fish and eggs, it was concluded that the likelihood of impact was by no means assured, even in these six cases. It was concluded that in most cases, current entrainment and impingement losses at six Ohio River power plants have little or no effect at the population level.

The value of long-term environmental monitoring programs: an Ohio River case study

“…Based on these occurrences, it has generally been found that, “the populations of these species…are more likely to be affected by changes in factors such as habitat, water quality, and the occurrence of floods, droughts, and temperature extremes, rather than the minor changes resulting from entrainment-impingement losses” (Perry et al 2002). Short-term sampling studies, without the benefit of statistical analyses to determine relationships with weather and other phenomenon, would not reach these same conclusions.…”

“…Due to this need for water, most power plants are located on rivers, lakes, oceans, and other water bodies and, as a consequence, can impact nearby fish populations. For example, cooling-water intake systems have the potential to impact aquatic organisms through impingement and entrainment (Lohner et al 2000; Perry et al 2002; Barnthouse 2013). Impingement is the entrapment of aquatic organisms on intake screens, while entrainment is the passing of aquatic organisms through these screens into the power plant cooling system.…”

“…For example, the ORERP electrofishing database from 1977 to 2003, the ORSANCO electrofishing database from 1991 through 2003 and the ORSANCO lock chamber rotenone database from 1958 through 2003 have been used to assess the potential impacts of fish impingement on the river’s fish populations (Lohner et al 2000; Perry et al 2002). Several fish species were selected for evaluation and several life history parameters (age, growth, fecundity, and age-specific survival) were used to project the populations in different river pools forward for a 50-year time period with and without fish impingement.…”

“…Several fish species were selected for evaluation and several life history parameters (age, growth, fecundity, and age-specific survival) were used to project the populations in different river pools forward for a 50-year time period with and without fish impingement. The projected changes ranged from a 3 % decrease for white bass ( Morone chrysops ) in the Robert Byrd pool to a 57 % increase for freshwater drum ( Aplodinotus grunniens ) in the same pool when the effects of the power plants were removed (Perry et al 2002). Since caution must be used when interpreting such results, a comparison was also made between the predicted increase and the observed population variability as documented in the electrofishing data over the past several years.…”

Ichthyofauna in the upper Rhine River close to the city of Karlsruhe as determined by the analysis of fish impingement by cooling-water intakes of a power plant

“…Fish species preferring the surface part of the water body might be underrepresented. The aim of the companies operating power stations using the once through water cooling technology should, however, be to minimize the impact of impingement on the fish fauna as much as possible (Perry, Seegert, Vondruska, Lohner, & Lewis 2002;Super & Gordon 2002;Veil, Puder, Littleton, & Johnson 2002) and the use of closed-cycle cooling or dry cooling would be more protective of the fish community. The ichthyofauna in the northern part of the upper Rhine should also be observed in the future to follow its development especially with respect to endangered and migrating species.…”