Impingement is the general term used for the collision of organisms with the filter screens protecting the water intakes. More loosely, it can also include weed and other debris caught on the screens. Typical fine screens have a mesh size of 5 or 10 mm, and will retain most adult fish and crustaceans. In many power stations impinged animals are killed in large numbers. Numbers of fish killed are typically in the hundreds of thousands to millions per year, while shrimps and prawns are impinged in millions of individuals per year.
The principal environmental concern relates to the loss of fish and the resulting damage to the local populations. Migratory species such as eels, salmonids, lampreys and shad may be especially vulnerable. Such problems are likely to be particularly marked in lakes or estuaries, and in coastal regions where direct-cooled power plants are concentrated. Read our LINKHEREfeature
which analyses the issue in British and Northern European waters. See also our LINKHEREreports on Hinkley Point
, where Pisces staff monitored fish and crustacean impingement every month for 39 years.
Pisces have acted as advisors to a variety of organisations on impingement, including Riverkeeper in the USA, and the Environment Agency, IFCA, Cefas and British Energy/EDF in the UK.
We have provided computer predictions of levels of fish impingement at proposed power station sites around the UK, using our own software
, which is based on many years of data of actual catches.
In 2019 we completed a 39-year monitoring program of fish impingement at Hinkley Point 'B' power station. We are continuing long-term monitoring programs (10 - 15 years so far) at other UK power stations.
Short-term monitoring programs
We are carrying out periodic short-term monitoring of fish impingement (including salmon/trout smolts and eels/elvers), entrainment, water quality, and the causes and impacts of CW discharge foaming, at a number of UK power stations, as well as other water abstractors.
Intensive impingement studies
We completed 4 years of intensive 24-hour impingement samples at 2 UK nuclear power plants, in connection with the proposals for new-build nuclear stations, providing an unparalleled volume of data on fish impingement.
Pisces is internationally recognised as expert
in the prediction and minimisation of impingement effects for both environmental and operational reasons - please contact us
for further information and assistance.
Software modelling & prediction
The PISCES (Predicting Inshore Saline Communities by Expert System) software package to predict fish impingement in cooling water intakes in N. European waters was developed by us, based on our unrivalled database on power station impingement, decades of monitoring data and the extensive experience of our staff. The PISCES expert system is available for lease or purchase - please contact us
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