VANDINDVINDINGENS BETYDNING FOR DE ØKOLOGISKE FORHOLD I VANDLØB / The Effect of Reduced Discharge on the Ecology of Streams
Most Danish streams have their discharge reduced due to withdrawal of water for field irrigational purposes. Reduced discharge creates a deteriorated stream environment, that is reduced depth, reduced water velocity, increased sedimentation of oxygen consuming organic substances, reduced reaeration of oxygen, and larger temperature excursions. These factors combined with an improved light regime at the stream bottom may lead to an earlier development of the biological components: Benthic algae and macrophytes thus to impact the stream oxygen budget for a longer period than in the unaffected situation necessitating additional stream management; e.g. weed cutting and dredging of sediment.