%0 Generic
%A Salgado, J
%A Shilland, EM
%A Battarbee, RW
%C London, UK
%D 2013
%F discovery:10114767
%I UCL Environmental Change Research Centre
%N 156
%T A review of liming as a technique for protecting salmonid fish populations in acidified surface waters
%U https://discovery.ucl.ac.uk/id/eprint/10114767/
%X Liming is a common technique that has been used in many countries to raise the alkalinity  of acidified surface waters and alleviate some of the damaging effects of acidification on  salmonid fish populations.  The most common liming substance used is calcite, a calcium carbonate compound that is  relatively inexpensive, available in different particle sizes and dissolves relatively quickly.  It can be applied directly to streams or lakes or it can be applied to catchment soils. When  applied to catchment soils its effect can be long-lasting but it can cause significant  damage to those catchment plant and animal communities that are naturally adapted to  acidic conditions. When applied directly to surface waters its effect can be immediate but  applications need to be continuous or frequently repeated to counter downstream dilution  and loss.  For streams the most effective method is to use an automatic doser controlled by pHmeasuring sensors upstream and downstream of the doser to enable the exact quantity of  lime needed to be added to the water body. Although effective this is an expensive  method and one that needs to be maintained continuously for several years until the  critical load exceedance has been eliminated. An alternative or complementary method is  partial catchment liming by targeting water sources and selected wetlands to minimise  damage to catchment vegetation.  Liming can be very effective in restoring and protecting salmonid fish populations, but if  over-applied it can lead to unwanted increases in alkalinity and productivity that may  produce symptoms of eutrophication and unwanted changes in the composition of plant  and algal communities downstream.